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We demonstrated experimentally an opportunity to form space grating patterns in Ag3AsS3 semiconductor crystals under an influence of coherent femtosecond (195 fs) laser beams. The observation of the laser stimulated gratings has been performed using a cw He–Ne laser with power about 15 mW at 1150 nm wavelength. The photoinducing femtosecond laser with pulse duration about 190 fs and frequency 65 MHz bandpass has been used in the two-beam coherent regime at wavelength 1045 nm. The set of dichroic mirrors, polarizers, and lenses have been applied to form two space-separated beams, which interact with the studied Ag3AsS3 trigonal single crystals. The treatment has been performed during additionally applied dc-electrical strength equal to about 8 kV/cm with a frequency about 20 kHz directed perpendicularly to the optical axis. The monitoring of the photo-thermal effects and photo-destruction have been done using the optical fiber spectrometer Ocean Optics with spectral resolution 1 nm.

In this paper, we present a novel design and an optical simulation of a flat concentrator photovoltaic (CPV) system for electric vehicle application. The sunlight concentration component is comprised of a planar waveguide integrated dichroic mirror-coated cone prisms and a mirror-coated lens array. Sunlight reflects firstly at the mirror-coated lens array and then strikes the cone prism of the planar waveguide. The prisms are coated by the dichroic mirrors to divide the solar spectrum into two bands. The low-energy band is transmitted and reaches the GaInAsP/GaInAs dual-junction solar cells. The mid-energy band is reflected at the prism surface and coupled inside the waveguide. The exit port of the waveguide is attached with GaInP/GaAs dual-junction solar cells. The simulation results demonstrated a maximum electricity conversion efficiency of 32.88% at the high concentration ratio. The system thickness is 35 mm, which is as thin as the conventional flat photovoltaic panel and system allow for a lateral sun-tracking mechanism. This is suitable for installation on the vehicle's roof. The results showed that the presented flat CPV system is a new approach for a highly efficient application of solar energy to the electrical vehicle.

The majority of pharmaceuticals currently in circulation are chiral compounds; mostly sold as equimolar mixtures of two enantiomers. Albeit, they have identical chemical structures, the human body metabolizes each enantiomer by separate pathways due to their different handedness. Hence, one isomer may exhibit the intended pharmaceutical effect, whereas the other exists as an inactive impurity or, occasionally, may engender undesirable side-effects and toxicity, like in the Softenon disaster which caused circa one thousand congenital disabilities (International Union of Crystallography, 2016). Therefore, it is imperative to promote chiral separation and analysis of chiral drugs in pharmaceutical manufacture to eliminate the undesirable enantiomer (Nguyen, He, & Pham-Huy, 2006). Recently, plasmonic-enhanced metamaterials have been shown to amplify the subtle circular dichroic effects of chiral molecules by many orders of magnitude, making enantioselective assays more precise by amplifying the CD signal, enabling discrimination of nuanced spectral features, never seen before (Nguyen et al., 2006). This paper advances the sensitivity of CD spectroscopy by studying a newly designed chiral woodpile nanostructure that uses plasmon-generated superchiral near fields to enhance the dissymmetry of chiral molecules and magnify their chiroptical effects. Simulated to outperform gammadion arrays proposed by competitor papers by 1206 %, it empowers increased measurement precision in the assessment of enantiomeric excess in the quality management of drug manufacture, increasing safety. Furthermore, it may potentially lead to earlier detection of diseases such as HIV and other viruses. Lastly, for the first time, this paper proposes a revolutionary but intuitive mechanism to explain the generation of the superchiral near field of a plasmonic-enhanced nanostructure. Shown to corroborate with simulation, it provides a more profound understanding of the underlying mechanisms beyond just the ‘plasmon-plasmon coupling’ which preceding works have already discussed. This knowledge opens up new avenues to develop nanostructures with even stronger circular dichroic properties. Article DOI: https://dx.doi.org/10.20319/mijst.2019.52.0119 This work is licensed under the Creative Commons Attribution-Non-commercial 4.0 International License. To view a copy of this license, visit http://creativecommons.org/licenses/by-nc/4.0/ or send a letter to Creative Commons, PO Box 1866, Mountain View, CA 94042, USA.

A short pitch cholesteric liquid crystal (CLC) acts as one-dimensional photonic crystals. It was widely studied for electro-optical switching devices. Although it was proposed for a switchable smart window, its spectral characteristics have critical limitations for window applications. In this report, we present dichroic-dye-doped short pitch CLC films, suitable for switchable window applications. The spectral limitations of a conventional CLC film in the voltage-off screening states were resolved by combining two different approaches of doping dichroic dye and increasing film thickness. Although each adjustment showed insufficient improvements, the implementation of a combined approach resulted in a drastically enhanced shielding performance in the voltage-off state, desirable for privacy windows. The increased film thickness promoted both the scattering focal conic and reflective multi-domain planar configurations for two different voltage-off states. The modified planar configuration caused a specific colored reflection with some turbidities. Furthermore, the dichroic dyes in both states effectively absorbed transmitting and scattered lights, resulting in the dark gray focal conic state and opaque colored reflection in the multi-domain planar state. Such combined efforts brought a great synergetic effect for enhancing a shielding efficiency. As a result, spectral properties of the voltage-off screening states were greatly different from the conventional CLC films, which show a milky white and tinted color, respectively, in a bright environment. The spectral performances of three switchable states were dramatically improved for the application of electrically switchable smart windows. The dichroic-dye-doped CLC films may be usefully adopted for switchable ultraviolet and heat windows if the cholesteric pitch and dichroic dyes are optimized for the corresponding wavelengths of electromagnetic radiation.

We accomplished controlling mechanochromic properties of propionylated hydroxypropyl cellulose (PHPC)/synthetic polymer cholesteric liquid crystalline (ChLC) composites by combining PHPC bearing residual hydroxyl groups with various synthetic polymers. The presence of hydroxyl groups contributed to the effective immoibilization of ChLC structure in the composites by allowing the “moderate” compatibility as well as hydrogen bonding between PHPC and diverse synthetic polymers. The obtained composite films exhibited not only wide-ranging color change but also circular dichroic inversion by applying the compressive stress. A recovery of the color and circular dichroism was realized through post thermal treatments. A level of the stress and temperature for expressing these properties was successfully manipulated by varying combined synthetic polymers. Hence, our present work can give a designing guideline for the cellulose-based mechanochromic materials with extensive physical properties.

The circular dichroism in cholesteric liquid crystals (CLCs) has been studied in the absorption bands of dissolved dichroic dyes possessing both the positive and negative linear dichroism. The circular dichroism is studied depending on the position of CLC selective reflection band with respect to the dye absorption band. The induced circular dichroism due to dye absorption is compared to intrinsic CLC circular dichroism due to the light diffraction from the periodic chiral structure.

To understand the mesoscale mechanisms responsible for the behavior of heterogeneous materials and to validate models, it is important to experimentally measure the deformation and temperature fields at the microstructure level. So far, there has been no methods that can yield such measurements simultaneously for dynamic experiments. Here, we report the development of a novel capability for simultaneous time- and space-resolved recording of both fields over the same microstructure area of a sample with micron-level spatial resolutions and microsecond time resolutions. Referred to as MINTED (Microscale In-situ Imaging of Dynamic Temperature and Deformation Fields), the system cohesively integrates a high-speed visible light (VL) camera and a state-of-the-art high-speed infrared (IR) camera via a custom-designed dichroic beam splitter-lens assembly. The combined VL and IR images allow the deformation fields to be obtained through digital image correlation (DIC) and the temperature fields over the same area to be obtained through pixel-level calibration of the differing emissivities of heterogeneous constituents in microstructures. Experiments are conducted on granular sucrose in a Kolsky bar [or split-Hopkinson pressure bar (SHPB)] environment, yielding both microstructure level fields along with overall material response. The strain and temperature fields provide detailed first-time insight into the processes of fracture, friction, shear localization, and hotspot development in the microstructures.

We present a study of the magnetic properties of a single-phase Dy0.2Nd0.8CrO3 compound. Interestingly, a negative exchange bias (EB) effect is observed for a wide range of temperature and, below T = 5 K, a small positive EB is also noticed, which is accompanied by a crossing of the Zero Field Cooling and Field Cooling (ZFC-FC) curves. Moreover, in contrast to many results reported in the literature, we do not verify a magnetic reversal, not even at low magnetic fields. The X-ray magnetic circular dichroism results show clear evidences of a dichroic signal for Cr L2,3 edges at T = 30 K under a magnetic field of H = 4 T. Our results suggest that a ferromagnetic ordering of the Cr3+ and the long-range ordering for the Nd3+ can play an important role in the observation of the positive EB in this compound.

Dichroic circular polarizers (DCP) represent an important group of optical filters that transfer only that part of the incident light with the desired polarization state and absorb the remainder. However, DCPs are usually bulky and exhibit significant optical loss. Moreover, the integration of these kinds of DCP devices can be difficult and costly as different compositions of chemicals are needed to achieve the desired polarization status. Circular polarizers based on metasurfaces require only thin films in the order of hundreds of nanometers but are limited by their sensitivity to angle of incidence. Furthermore, few existing solutions offer broadband operation in the visible range. By using computational simulations, this paper proposes and analyses a plasmonic DCP structure operating in the visible, from 400 nm to 700 nm which overcomes these drawbacks. The resulting circular dichroism transmission (CDT) is more than 0.9, and the maximum transmission efficiency is greater than 78% at visible wavelengths. These CDT characteristics are largely independent of angle of incidence up to angles of 80 degrees.

Recently, the field of laser radiation detection LRD has witnessed a great development in the past three decades; there has been a great development in the field of semiconducting devices and optical systems to achieve high-performance LRD. Many important applications mainly depend on LRD in Civilian and military fields, like LIDAR systems, remote sensing, optical fiber communication system, and in military application laser-guided bomb LGB and laser warning receiver LWS. In all these applications, the laser sensors are chosen according to the requirements of the application in terms of sensitivity, a field of view, and the speed of the sensor's response in terms of converting the optical signal into electrical. In this paper, three-channel dichroic beam splitters, sky cameras, and a main optical system are utilized to identify the wavelengths of the incident laser radiation in the far-field. The optical system is designed to give a high-quality monochromatic image of LIDAR receivers and neglect a background noise from sunlight. The main contribution of This optical system is to reduce the electronic components and increase the optical components to enhancement the signal-to-noise ratio to achieve more than 50 dB in clear weather conditions of a LIDAR receiver by using the dichroic beam splitter technique with a sky cameras detector.

In multiphoton ionization of atoms, elliptical dichroism may arise in the photoelectron angular distributions due to the interference of the possible ionization pathways. We here consider the interaction of atoms with an elliptically polarized biharmonic ($\ensuremath{\omega} + 2\ensuremath{\omega}$) field which simultaneously allows one- and two-photon ionization of the atoms. The interference between these two ionization pathways introduces contributions to the elliptical dichroism in addition to the dichroism that arises from the two-photon ionization alone. We show that these additional dichroism contributions can lead to a stronger dichroism in comparison to the one arising from two-photon ionization only. We present a relativistic analysis of the corresponding photoelectron angular distributions and discuss individual contributions to the dichroic phenomena. Detailed computations have been performed for biharmonic ionization of neutral helium atoms.

Over the last decade, lasers with low quantum defects have attracted special attention as they can provide generation of ultra-short pulses simultaneously with high average power. The quantum defect is due to the difference between the energy of the pump and emitting photons. To minimise the thermal load in a laser and provide a wide bandwidth of emission often requires laser crystals with ultra-low quantum defect, having a difference between the pump and the emission wavelength of only a few tens of nm. For example, in the frequently used end-pumping of Yb: crystalline media, the dichroic mirror of the resonator has to exhibit a steep spectral change of reflection to pass the pump and simultaneously to reflect the emission wavelength. The overlap between absorption and luminescence bands in these lasers is a challenge for well-established dielectric coating technology, especially at high laser powers. The recently developed concept of optical metasurfaces based on a single layer of dielectric nanostructures can provide high-reflectivity over a broad spectral range [1] – [2] . However, the application of a metasurface as a mirror with pronounced dichroic properties in power-scalable lasers has not been studied so far. Here we demonstrate the design and implementation of metasurface mirror with a steep spectral change of its reflection. The single-mode stable diode pumped Yb-laser operation has been achieved using this dichroic metasurface mirror (DMM) as a pump cavity mirror.

Thanks to their excellent thermal and spectral properties [1] and the possibility to pump them by high-power diodes, Yb-doped gain materials have revolutionized many application areas in ultrafast science [2] . However, laser oscillators based on those gain materials have so far been severely limited in power and efficiency for operation in the sub-30-fs regime [3] , [4] . Standard collinearly-pumped Yb-doped bulk laser oscillators use dichroic mirrors with a high transmission for the pump at around 980 nm and a high reflectivity at the lasing wavelengths. This leads to a strongly varying group delay dispersion (GDD) and limits the expansion of the optical spectrum towards short wavelengths [3] . Furthermore, to reach higher power levels, increased output coupling is required, resulting in a stronger population inversion. For common broadband Yb-doped gain materials such as Yb:CALGO, this shifts the gain maximum towards shorter wavelengths until reaching the spectral edge of the dichroic mirrors. Both reasons set a severe limitation to fully exploit the available gain bandwidth for the generation of even shorter pulses and hinder further power scaling of Yb-doped bulk oscillators in the few-cycles regime. Here, we show that we can overcome these spectral and power limitations by using a novel pump mirror design relying on cross-polarized optical pumping.

ELOIS VISWIR is a science-grade, smallsat compatible, pushbroom hyperspectral payload covering the entire VISWIR spectral range (400-2450 nm) with over 200 contiguous 10 nm wide spectral bands. Its unique all reflective optical design enables covering a 70 km swath with 35 m ground sampling distance (GSD), while guaranteeing high imaging performances across the full field of view. At the core of the instrument, the spectrometer formula expands upon AMOS’ state of the art Offner-based ELOIS VNIR long-slit spectrometer [1], including key features such as built-in slit de-magnification, and the use of a fine-tuned freeform diffraction grating enabling the appropriate compensation of the optical aberrations affecting the fast, F/2.1 focal plane. Besides its excellent imaging performances and advanced control of distortions, the ELOIS VISWIR delivers unparalleled throughput in a single optical chain thanks to the inclusion of leading-edge technical solutions including a broadband multi-blazed freeform diffraction grating, a variable dichroic beam-splitter plate, and high efficiency order sorting filters. In this paper, we discuss these key ingredients in the optical design of the ELOIS VISWIR spectrometer and report the optical performances of the manufactured optical components.

International audience; Localized surface plasmon resonance (LSPR) of metal nanoparticles are widely used to develop plasmonic sensors, which permit to detect minute amounts of molecular compounds. Two methods of measurements are commonly used. The first most common mode, which investigates the shift in wavelength of the LSPR induced by the analyte, requires the use of high-resolution monochromators. The second mode, based on self-reference or perfect absorbing systems, measures the changes of the signal intensity, and requires the use of sophisticated samples elaborated by lithography techniques. In this article, we adapt the very sensitive transmittance anisotropy spectroscopy technique with anisotropic plasmonic gold films, formed of slightly elongated nanoparticles easily elaborated by grazing deposition on microscopy glass slides. These films display two different LSPR, caused by their morphological anisotropy, as a function of the light polarization. Working at a single wavelength, we experimentally demonstrate an ultrahigh sensitivity to bulk refractive index sensing, with a resolution below delta_n=10-4 . The factor of merit (FoM*), defined for intensity-based plasmonic sensors, reaches the outstanding value of 23 000, which is due to the null optical anisotropy signal initially measured, thus granting an enhanced optical contrast when changing the RI. Furthermore, sensitivity down to four avidin molecules per square micron of the sample is theoretically shown, which offers a promising route towards easily made ultra-sensitive miniaturized plasmonic sensors, compatible with microfluidic systems, without the need for a monochromator.

The absolute configuration of chiral 2-aryl and 2-aryloxy propionic acids, which are among the most common chiral environmental pollutants, has been readily and reliably established by either electronic circular dichroism spectroscopy or optical rotation measurements employing suitably designed 4,4′-disubstituted biphenyl probes. In fact, the 4,4′-biphenyl substitution gives rise to a red shift of the diagnostic electronic circular dichroism signal of the biphenyl A band employed for the configuration assignment, removing its overlap with other interfering dichroic bands and allowing its clear sign identification. The largest A band red shift, and thus the most reliable results, are obtained by employing as a probe the 4,4′-dinitro substituted biphenylazepine 3c. The method was applied to the absolute configuration assignment of 2-arylpropionic acids ibuprofen (1a), naproxen (1b), ketoprofen (1c) and flurbiprofen (1d), as well as to the 2-aryloxypropionic acids 2-phenoxypropionic acid (2a) and 2-naphthoxypropionic acid (2b). This approach, allowing us to reveal the sample’s absolute configuration by simple optical rotation measurements, is potentially applicable to online analyses of both the enantiomeric composition and absolute configuration of these chiral pollutants.

Soiling effects influence the output of solar thermal plants, significantly causing unwanted transmittance, reflectance, and absorbance losses. Research is needed to identify what type of reflective surfaces are best suited for semitropical climates, such as the southeastern United States. This paper initially presents a review of several concentrating solar power (CSP) reflector testbeds used to analyze the soiling effects of various reflective materials. A soiling testbed is developed for this study that comprised six sets of reflective surfaces mounted at a fixed tilt of 30 degrees: three sets of thin-film surfaces and three sets of glass types. Two generations of 3M solar mirror film (SMF), 3M SMF 1100 and 3M SMF 2020, were used along with Konica Minolta SMF, silvered Corning Willow Glass, a dichroic cold mirror, and a standard mirror. Results show that the 3M SMF 2020 and Konica Minolta SMF performed the best during regular cleaning intervals, whereas the silvered Corning Willow Glass gave the best performance if only cleaned naturally. The other glass types showed the least average loss due to soiling throughout this study but gave the lowest performance for specular reflection.

Fluorescence standards allow for quality control and for the comparison of data sets across instruments and laboratories in applications of quantitative fluorescence. For example, users of microscopy core facilities expect a homogenous and time-invariant illumination and a uniform detection sensitivity, which are prerequisites for quantitative imaging analysis, particle tracking or fluorometric pH or Ca2+-concentration measurements. Similarly, confirming the three-dimensional (3-D) resolution of optical sectioning micro-scopes prior to volumetric reconstructions calls for a regular calibration with a standardised point source. Typically, the test samples required for such calibration measurements are different ones, and they depend much on the very microscope technique used. Also, the ever-increasing choice among these techniques increases the demand for comparison and metrology across instruments. Here, we advocate and demonstrate the multiple uses of a surprisingly versatile and simple 3-D test sample that can complement existing and much more expensive calibration samples: simple commercial tissue paper labelled with a fluorescent highlighter pen. We provide relevant sample characteristics and show examples ranging from the sub-µm to cm scale, acquired on epifluorescence, confocal, image scanning, two-photon (2P) and light-sheet microscopes.Graphical abstractPyranine-labeled tissue paper, imaged upon 405-nm epifluorescence excitation through a 455LP LP dichroic and 465LP emission filter. Objective ×20/NA0.25. Overlaid are the normalised absorbance (dashed) and emission spectra (through line), respectively. In the present work we show that this “primitive” and inexpensive three-dimensional (3-D) test sample is a surprisingly versatile and powerful tool for quality assessment, comparison across microscopes as well as routine metrology for optical sectioning techniques, both for research labs and imaging core facilities.Research highlights-highlighter-pen marked tissue paper is a surprisingly powerful and versatile test sample for 3-D fluorescence microscopies-standard tissue paper presents features ranging from 400 nm to centimetres-our sample can simultaneously be used for testing intensity, field homogeneity, resolution, optical sectioning and image contrast-it is easy to prepare, versatile, photostable and inexpensive

Using angle-resolved photoelectron spectroscopy (ARPES), we investigate the surface electronic structure of the magnetic van der Waals compounds MnBi_{4}Te_{7} and MnBi_{6}Te_{10}, the n=1 and 2 members of a modular (Bi_{2}Te_{3})_{n}(MnBi_{2}Te_{4}) series, which have attracted recent interest as intrinsic magnetic topological insulators. Combining circular dichroic, spin-resolved and photon-energy-dependent ARPES measurements with calculations based on density functional theory, we unveil complex momentum-dependent orbital and spin textures in the surface electronic structure and disentangle topological from trivial surface bands. We find that the Dirac-cone dispersion of the topologial surface state is strongly perturbed by hybridization with valence-band states for Bi_{2}Te_{3}-terminated surfaces but remains preserved for MnBi_{2}Te_{4}-terminated surfaces. Our results firmly establish the topologically nontrivial nature of these magnetic van der Waals materials and indicate that the possibility of realizing a quantized anomalous Hall conductivity depends on surface termination.

An important step towards the commercialization of quantum technology is the miniaturization of nowadays tabletop setups. The Hanbury Brown-Twiss (HBT) configuration is an important building block in many quantum optics experiments. Within this contribution, we present and compare different concepts for realizing a miniaturized, fiber-coupled HBT configuration, which will be robust and adjustment free. The design process is based on ray tracing simulations, with the aim of finding the best compromise regarding the level of miniaturization and detection efficiency. As an application example, the detection of the luminescence of two different charge states of nitrogen vacancy (NV) centers in diamond is used. For this reason, in contrast to the actual HBT experiment, a dichroic beam splitter is used.

Context Polarisation is a decisive method to study the inner region of active galactic nuclei (AGNs) since, unlike classical imaging, it is not affected by contrast issues. When coupled with high angular resolution (HAR), polarisation can help to disentangle the location of the different polarising mechanisms and then give insight into the physics taking place in the core of AGNs. Aims We obtained a new data set of HAR polarimetric images of the archetypal Seyfert 2 nucleus of NGC 1068 observed with SPHERE/VLT. We aim in this paper to present the polarisation maps and to spatially separate the location of the polarising mechanisms, thereby deriving constraints on the organisation of the dust material in the inner region of this AGN. Methods With four new narrow-band images between the visible and the near-infrared combined with older broad-band observations, we studied the wavelength dependence of the polarisation properties from 0.7 to 2.2 μm of three selected regions within the inner 2″ surrounding the central engine. We then compared these measurements to radiative transfer simulations of scattering and dichroic absorption processes, using the Monte Carlo code MontAGN. Results We establish a detailed table of the relative importance of the polarising mechanism as a function of aperture and wavelength. We are able to separate the dominant polarising mechanisms in the three regions of the ionisation cone, the extended envelope of the torus, and the very central bright source of the AGN. Thus, we estimate the contribution of the different polarisation mechanisms to the observed polarisation flux in these regions. Dichroic absorption is estimated to be responsible for about 99% of the polarised flux coming from the photo-centre. However, this contribution would only be restricted to this location because the double-scattering process would be the most important contributor to polarisation in the equatorial plane of the AGN and single scattering is dominant in the polar outflow bi-cone. Conclusions Even though results are in good agreement with larger apertures measurements, the variety of situations with different mechanisms at play highlights the importance of spatial resolution for the interpretation of polarisation measurements. We also refine the estimation of the integrated optical depth in the visible of the obscuring structure to a range of 20−100, constraining the geometry of the inner region of this AGN., Astronomy & Astrophysics, 648, ISSN:0004-6361, ISSN:1432-0746

Laser beam scanners (LBS) are an emerging micro-display technology for augmented reality (AR) head-mounted displays (HMD), enabling small-form-factor and low-power display units with large field of view (FOV) and daylight-bright luminance, that are compatible with a large range of optical combiner technologies such as waveguide or holographic combiners. We have developed an ultra-compact and lightweight LBS comprising an integrated laser module, a single 2D micro-electro-mechanical systems (MEMS) mirror, and a molded interconnect device (MID). The compact integrated laser module contains red, green, and blue (RGB) semiconductor laser diodes (LDs) and a common system of microlenses for beam collimation, all enclosed in a single hermetically sealed package. The three LDs are mounted onto a single submount using a novel high-precision laser die bonding technique. This high-precision LD placement allows the use of collimation lenses that collimate all three laser beams simultaneously in contrast to separate lenses with additional active alignment steps for each color. No additional optical components such as mirrors and dichroic beam combiners are required—instead, the color channels are overlapped on a pixel-by-pixel basis by a “software beam combination” laser pulse timing algorithm. Both laser module and MEMS mirror are assembled on an MID with printed circuit board (PCB), which is connected to a driver board including video interface. We also give an outlook to future generations of fully mass manufacturable LBS systems with even smaller form factor.

Future manned missions to the Moon would require an uplink channel significantly broader in frequency than the ones presently used in S and X band. For this reason, the European Space Agency is considering to upgrade its 35-m deep space antennas to include an uplink channel also in K-Band (22.55-23.15 GHz). This paper addresses a solution where dichroic mirrors are used to accomplish this task. In particular, two solutions based on different manufacturing technologies are thoroughly compared taking into account different perspectives. Mirror designs and simulated results, for both dichroic mirrors and Beam Waveguide optics, are presented.

Nonlinear optics, and particularly second harmonic generation (SHG), is increasingly used in many modern disciplines from material characterization in physical sciences to bio-imaging in medicine and optical signal processing in information technology. We present a theoretical analysis providing a strong estimate for the energy-integrated SHG response. Requirements of symmetry in time and space are fully respected in the calculation, and estimates of natural and magnetic circular dichroic signals are superior to previous ones. Like symmetry requirements are traced in the amplitude for magnetic neutron scattering, which includes all axial and polar (Dirac) contributions. Our method of working, in terms of spherical multipoles and implementation of symmetry, could be of use in a variety of other probes of electronic properties.

Flat optics allow the production of integrated, lightweight, portable and wearable optical devices. In this work we propose a flat optics design platform that employs concepts from evolutionary algorithms to deep learning with convolutional neural networks, and demonstrate a general design framework that can furnish an arbitrarily designed system response in as little as 50nm of silicon. The proposed framework is fundamental for our most recent experimental paper, in which we present a plethora of high efficiency devices, including, but not limited to: polarizing beam splitters, dichroic mirrors and metasurfaces for a novel 2-pixel display technology.

Polarized Fourier transform infrared FTIR spectroscopy has been used extensively to monitor orientation for polymer quality control and optimized the mechanical properties. In the manufacturing process, using an in-line portable spectrometer would be a great advantage providing near real-time feedback during polymer production processes including temperature, and drawing/stretching. The goal is to let the chains within a polymer disentangle and become more systematic/oriented with predictable properties. In this work, we present a measurement technique using microelectromechanical system (MEMS) based polarization controlled Fourier transform spectrometer in the extended near-infrared used to monitor the polymer quality. The spectrometer is operating in the wavelength range of 1300 nm to 2600 nm (about 3846 cm-1 to 7692 cm-1) with a spectral resolution of 66 cm-1. The polarized-FTIR data were collected for a commercial plastic CD sleeve with thickness of about 1 mm in transmission mode. An ultra-broadband wire grid linear polarizer is used, inserted in the light path and rotated 360o in steps 10o. The polarizer orientation is kept in the same position for both background and sample measurements. The dichroic ratios of different absorption bands have been determined with the polarizer oriented parallel and perpendicular to a reference direction. The orientation quality of the polymer can be detected from the dichroic ratio with dichroic ratio equals to one representing an isotropic material. Comparison with a benchtop device is conducted showing good agreement. The presented solution paves the way for a low-cost and portable device for on-line polymer quality control.

Multimodal imaging is an advantageous method to increase the accuracy of disease classification. As an example, we and others have shown that optical coherence tomography images and fluorescence spectroscopy contain complementary information that can increase the sensitivity and specificity for cancer detection. A common challenge in multimodal imaging is image co-registration. The different images are often taken with separate imaging setups, making it challenging to precisely image the same tissue area or co-register the images computationally. To solve this problem, we have developed a co-registered multimodal imaging system that images the same tissue location with reflectance, multi-photon, and optical coherence microscopy. The co-registration mechanism is a dual-clad fiber that integrates with a scanning microscope or scanning endoscope, collecting all three signals using the same optical path. In the current implementation, optical coherence tomography utilizes a 1300 nm super luminescent diode, multi-photon signals are excited by a custom femtosecond 1400 nm fiber laser producing two- and three-photon signals in the 460-900 nm band, and reflectance imaging operates at 561 nm. The system separates the different signals using fiber wavelength division multiplexers, a dual-clad fiber coupler, and dichroic mirrors to deliver the different signals to the corresponding detector. This wavelength selection enables the system to work passively, meaning that there is no need for devices such as filter wheels. Using the scanning microscope configuration, we have obtained multimodal images of ex-vivo ovine ovary tissue.

International audience; We study laser-induced contamination (LIC) as a potential cause of optical losses and laser-induced damage of optical components for ultrashort pulse lasers with high average power in the MHz regime. Our work is conducted on dichroic mirrors designed for maximum reflection at 515 nm operated in ambient air. Based on the development of an experimental set-up for real-time monitoring of LIC and accelerated test protocols, we have conducted a parametric study on LIC development and studied its growth dynamics and morphology. We show that LIC is a main limitation of short-wavelength, high average power fs/ps lasers, with the formation of nanometric highly absorbing layers of carbonate compounds on the laser footprint, with evidence of thermal effects. It is also found that the last layer of the stack, at the interface between air and coating stack, is critical in the LIC growth which can open some perspectives for limitation of this effect.

Exploring 2D ultrawide bandgap semiconductors (UWBSs) will be conductive to the development of next-generation nanodevices, such as deep-ultraviolet photodetectors, single-photon emitters, and high-power flexible electronic devices. However, a gap still remains between the theoretical prediction of novel 2D UWBSs and the experimental realization of the corresponding materials. The cross-substitution process is an effective way to construct novel semiconductors with the favorable parent characteristics (e.g., structure) and the better physicochemical properties (e.g., bandgap). Herein, a simple case is offered for rational design and syntheses of 2D UWBS GaPS4 by employing state-of-the-art GeS2 as a similar structural model. Benefiting from the cosubstitution of Ge with lighter Ga and P, the GaPS4 crystals exhibit sharply enlarged optical bandgaps (few-layer: 3.94 eV and monolayer: 4.50 eV) and superior detection performances with high responsivity (4.89 A W-1 ), high detectivity (1.98 × 1012 Jones), and high quantum efficiency (2.39 × 103 %) in the solar-blind ultraviolet region. Moreover, the GaPS4 -based photodetector exhibits polarization-sensitive photoresponse with a linear dichroic ratio of 1.85 at 254 nm, benefitting from its in-plane structural anisotropy. These results provide a pathway for the discovery and fabrication of 2D UWBS anisotropic materials, which become promising candidates for future solar-blind ultraviolet and polarization-sensitive sensors.

The red emission of Eu3+ ions embedded in glasses containing copper with distinct plasmonic properties is reported. Either a photoluminescence (PL) enhancement or quenching is manifested depending on whether the nanocomposite is dichroic (scatters red but transmits blue) or not (ruby-colored). In addition, Eu3+ emission in the dichroic glass is indicated to be either enhanced or quenched depending on the excitation wavelength. The glasses consisting of barium–phosphate matrix co-doped with Cu and Eu were obtained by thermal processing. Characterizations were then performed by Fourier transform-infrared spectroscopy, UV/Vis optical absorption, PL spectroscopy with decay dynamics assessment, and light scattering measurements. The latter were conducted for the first time on plasmonic metal nanocomposite glasses, aiming to clarify the origin of the distinct optical properties. It is supported that favorable conditions for the PL enhancement are achieved when the emission of Eu3+ ions can benefit from light scattering by plasmonic Cu particles. However, an excitation energy transfer from Eu3+ to Cu nanoparticles via interband transitions leading to the PL quenching should be minimized.

A new, to the best of our knowledge, output coupler (OC) with enhancement of the cavity reflectivity is proposed to remarkably elevate the output powers and efficiencies of diode-pumped N d : G d V O 4 / K G W Raman yellow-orange lasers. The cavity reflectivity is effectively increased by using the double-sided dichroic coating on the OC. In comparison with the conventional single-sided coating, the conversion efficiency can be boosted from 15% to 26.3% in the experiment of a yellow laser at 578.8 nm, and the maximum output power can be increased from 5.7 to 10.5 W in the quasi-continuous-wave mode with 50% duty cycle and frequency of 500 Hz. Furthermore, in the operation of an orange laser at 588 nm, the maximum output power can be improved from 5.6 to 7.0 W by replacing the conventional OC with the new one.

The Simons Observatory (SO) will be a cosmic microwave background (CMB) survey experiment with three small-aperture telescopes and one large-aperture telescope, which will observe from the Atacama Desert in Chile. In total, SO will field over 60,000 transition-edge sensor (TES) bolometers in six spectral bands centered between 27 and 280 GHz in order to achieve the sensitivity necessary to measure or constrain numerous cosmological quantities, as outlined in The Simons Observatory Collaboration et al. (2019). The 6~m Large Aperture Telescope (LAT), which will target the smaller angular scales of the CMB, utilizes a cryogenic receiver (LATR) designed to house up to 13 individual optics tubes. Each optics tube is comprised of three silicon lenses, IR blocking filters, and three dual-polarization, dichroic TES detector wafers. The scientific objectives of the SO project require these optics tubes to achieve high-throughput optical performance while maintaining exquisite control of systematic effects. We describe the integration and testing program for the SO LATR optics tubes that will verify the design and assembly of the optics tubes before they are shipped to the SO site and installed in the LATR cryostat. The program includes a quick turn-around test cryostat that is used to cool single optics tubes and validate the cryogenic performance and detector readout assembly. We discuss the optical design specifications the optics tubes must meet to be deployed on sky and the suite of optical test equipment that is prepared to measure these requirements.

Orientation analysis of the β-sheet structure within films of the established recombinant spider silk protein eADF4(C16) was performed using a concept based on dichroic transmission- and attenuated total reflection-Fourier transform infrared spectroscopy, lineshape analysis, assignment of amide I components to specific vibration modes, and transition dipole moment directions of β-sheet structures. Based on the experimental dichroic ratio R, the order parameter S of β-sheet structures was calculated with respect to uniaxial orientation. Films of eADF4(C16) were deposited on untexturized (Si) and unidirectionally scratched silicon substrates (Si-sc) and post-treated with MeOH vapor. Freshly cast thin and thick eADF4(C16) films out of hexafluoroisopropanol featured β-sheet contents of ≈6%, which increased to >30% after MeOH post-treatment in dependence of time. Pseudo-first order folding kinetics were obtained, suggesting a transition from an unfolded to a folded state. In MeOH post-treated thin films with diameters in the nanometer range, a significant orientation of β-sheets was obtained regardless of the texturization of the silicon substrate (Si, Si-sc). This was rationalized by dichroic ratios of the amide I component at 1696 cm-1 assigned to the (0, π) mode of antiparallel β-sheet structures, whose transition dipole moment M is located in parallel to both β-sheet plane and chain direction. The calculated high molecular order parameter S ≈ 0.40 suggested vertically (out-of-plane) oriented antiparallel β-sheet stacks with tilt angles of γ ≈ 39° to the surface normal. Microscale (thick) films, in contrast, revealed low order parameters S ≈ 0. Scanning force microscopy on thin eADF4 films at silicon substrates showed dewetted polymer film structures rather at the micro-scale. These findings give new insights in the role of the β-sheet crystallite orientation for the mechanical properties of spider silk materials.

It is shown how soft X-ray nanospectroscopy maps of powders (particle size ∼200 nm) can be analyzed to quantitatively retrieve X-ray linear dichroism (XLD) parameters. A computational modeling procedure is described that can be used in conjunction with Monte Carlo simulations to prove statistical dissimilarity of XLD parameters between different samples., X-ray linear dichroism (XLD) is a fundamental property of many ordered materials that can for instance provide information on the origin of magnetic properties and the existence of differently ordered domains. Conventionally, measurements of XLD are performed on single crystals, crystalline thin films, or highly ordered nanostructure arrays. Here, it is demonstrated how quantitative measurements of XLD can be performed on powders, relying on the random orientation of many particles instead of the controlled orientation of a single ordered structure. The technique is based on a scanning X-ray transmission microscope operated in the soft X-ray regime. The use of a Fresnel zone plate allows X-ray absorption features to be probed at ∼40 nm lateral resolution – a scale small enough to probe the individual crystallites in most powders. Quantitative XLD parameters were then retrieved by determining the intensity distributions of certain diagnostic dichroic absorption features, estimating the angle between their transition dipole moments, and fitting the distributions with four-parameter dichroic models. Analysis of several differently produced ZnO powders shows that the experimentally obtained distributions indeed follow the theoretical model for XLD. Making use of Monte Carlo simulations to estimate uncertainties in the calculated dichroic model parameters, it was established that longer X-ray exposure times lead to a decrease in the amplitude of the XLD effect of ZnO.

The perylene bisimide derivative Paliogen Black (P-black) is proposed as a new chromogenic probe that shows visible (vis) and near-infrared (NIR) responses after mechanical solicitations of host linear low-density polyethylene (LLDPE) films. P-black is reported to display strong absorption in the vis spectrum and unusual reflective and cooling features in the NIR region. Uniaxial deformation of the 2.5, 5, and 10 wt% P-black/LLDPE films yields a dichroic absorption under polarized light with color variations attributed by the computational analysis to the distinct anisotropic behavior of the transition dipole moments of P-black chromophores. When LLDPE films are deformed, P-black aggregates reduce their size from ≈30-40 µm to ≈5-10 µm that, in turn, causes reflectivity losses of about 30-40% at the maximum elongation. This gives rise to warming of 5-6 °C of the locally oriented film placed in contact with a black substrate under the illumination with an IR lamp for 5 s. These features combined with the high sensitivity of the vis-NIR response toward mechanical solicitations render P-black as a new solution to detect uniaxial deformations of plastic films through both optical and thermal outputs.

Full list of authors: Dhillon, V. S.; Bezawada, N.; Black, M.; Dixon, S. D.; Gamble, T.; Gao, X.; Henry, D. M.; Kerry, P.; Littlefair, S. P.; Lunney, D. W.; Marsh, T. R.; Miller, C.; Parsons, S. G.; Ashley, R. P.; Breedt, E.; Brown, A.; Dyer, M. J.; Green, M. J.; Pelisoli, I.; Sahman, D. I. Wild, J.; Ives, D. J.; Mehrgan, L.; Stegmeier, J.; Dubbeldam, C. M.; Morris, T. J.; Osborn, J.; Wilson, R. W.; Casares, J.; Muñoz-Darias, T.; Pallé, E.; Rodríguez-Gil, P.; Shahbaz, T.; Torres, M. A. P.; de Ugarte Postigo, A.; Cabrera-Lavers, A.; Corradi, R. L. M.; Domínguez, R. D.; García-Alvarez, D., HiPERCAM is a portable, quintuple-beam optical imager that saw first light on the 10.4-m Gran Telescopio Canarias (GTC) in 2018. The instrument uses re-imaging optics and four dichroic beamsplitters to record us, gs, rs, is, zs (320-1060 nm) images simultaneously on its five CCD cameras, each of 3.1-arcmin (diagonal) field of view. The detectors in HiPERCAM are frame-transfer devices cooled thermo-electrically to 183 K, thereby allowing both long-exposure, deep imaging of faint targets, as well as high-speed (over 1000 windowed frames per second) imaging of rapidly varying targets. A comparison-star pick-off system in the telescope focal plane increases the effective field of view to 6.7 arcmin for differential photometry. Combining HiPERCAM with the world's largest optical telescope enables the detection of astronomical sources to gs ∼23 in 1 s and gs ∼28 in 1 h. In this paper, we describe the scientific motivation behind HiPERCAM, present its design, report on its measured performance, and outline some planned enhancements. © 2021 The Author(s) Published by Oxford University Press on behalf of Royal Astronomical Society., HiPERCAM was funded by the European Research Council under the European Union's Seventh Framework Programme (FP/20072013) under ERC-2013-ADG GrantAgreement no. 340040 (HiPERCAM), with additional funding for operations and enhancements provided by the Science and Technology Facilities Council (STFC). This paper is based on observations made with the Gran Telescopio Canarias, installed at the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofísica de Canarias, on the island of La Palma. SGP acknowledges the support of an STFC Ernest Rutherford Fellowship. PR-G and TMD acknowledge support from the State Research Agency (AEI) of the Spanish Ministry of Science, Innovation and Universities (MCIU), and the European Regional Development Fund (FEDER) under grant AYA2017-83383-P. MAPT and TM-D acknowledge support via Ram ' on y Cajal Fellowships RYC-2015-17854 and RYC-201518148., With funding from the Spanish government through the Severo Ochoa Centre of Excellence accreditation SEV-2017-0709.

Biominerals such as seashells, corals skeletons, bone, and enamel are optically anisotropic crystalline materials with unique nano- and micro-scale organization that translates into exceptional macroscopic mechanical properties, providing inspiration for engineering new and superior biomimetic structures. Here we use particles of Seriatopora aculeata coral skeleton as a model and demonstrate, for the first time, x-ray linear dichroic ptychography. We map the aragonite (CaCO3) crystal c-axis orientations in coral skeleton with 35 nm spatial resolution. Linear dichroic phase imaging at the O K-edge energy shows strong polarization-dependent contrast and reveals the presence of both narrow (< 35{\deg}) and wide (> 35{\deg}) c-axis angular spread in sub-micrometer coral particles. These x-ray ptychography results were corroborated using 4D scanning transmission electron nano-diffraction on the same particles. Evidence of co-oriented but disconnected corallite sub-domains indicates jagged crystal boundaries consistent with formation by amorphous nanoparticle attachment. Looking forward, we anticipate that x-ray linear dichroic ptychography can be applied to study nano-crystallites, interfaces, nucleation and mineral growth of optically anisotropic materials with sub-ten nanometers spatial resolution in three dimensions.

The dichroic nature of Lycurgus cup glass exposed at British Museum and prepared by ancient roman glassmakers (IV c. AD) is still exciting the researchers minds and for this reason a series of replica glasses with optical properties and composition similar to Lycurgus cup glass has been prepared by secondary heat treatment. The glass microstructure has been investigated by SEM showing the occurrence of a phase separation in the form of droplets enriched with silica which crystallizes over time into the α-quartz. The phase separation is due to the Fe2+, Fe3+ and P2O5 species that could enter the glass batch occasionally as also made by Au and Ag nanoparticles (NPs). The NPs size has been estimated according to Mie theory. It has been proposed that the wine-red color in transmitted light is due to the absorption of light by the metal NPs, whereas the olive-green color of glass, in reflected light, is mainly caused by Fe2+ and Fe3+ absorption and Rayleigh scattering on droplets.

Time-dependent density functional theory (TDDFT) simulations are conducted on a series of chiral gold nanowires to explore whether an enhancement of circular dichroism at the plasmon resonance is possible and identify its quantum-mechanical origin. We find that in linear two-dimensional chiral nanowires the dichroic response is suppressed by destructive interference of nearly degenerate components with opposite signs, pointing to this phenomenon as a common and likely origin of the difficulty encountered so far in achieving a plasmonic CD response in experiment and suggesting nevertheless that these opposite components could be "decoupled" by using multiwall arrangements. In contrast, we predict a giant dichroic response for nanowires with three-dimensional helical coiling. We rationalize this finding via an electronic structure analysis of longitudinal and transversal plasmonic excitations and their coupling into chiral components, and we propose a simple formula for the chiral response as a function of structural parameters (nanowire length and coiling number).

Nanophotonic chiral antennas exhibit orders of magnitude higher circular dichroism (CD) compared to molecular systems. Merging magnetism and structural chirality at the nanometric level allows for the efficient magnetic control of the dichroic response, bringing exciting new prospects to active nanophotonic devices and magnetochirality. Here we devise macroscale enantiomeric magnetophotonic metasurfaces of plasmon and ferromagnetic spiral antennas. Mixed 2D- and 3D- chiral nanoantennas induce large CD response, where we identify reciprocal and non-reciprocal contributions. The simultaneous chiroptical and magneto-optical response in a wide spectral range with these metasurfaces delivers an attractive platform for the study of magnetochirality at the nanoscale. Exploring further this type of magnetophotonic metasurfaces allows the realization of high-sensitivity chiral sensors and prompts the design of novel macroscopic optical devices operating with polarized light., Main text: 5 pages, 3 figures. Supporting information: 6 pages, 6 figures

Metallic nanoparticles are small particles, with dimensions of less than 100 nm, which have unique characteristics. For example, the color of a nanoparticle solution is given by the surface plasmon resonance, in contrast to only absorbance of a molecule. Metallic nanoparticles have been used in the antiquity for the production of colored glass. Many of the medieval cathedral red windows are in fact, stained with gold nanoparticles. However, presenting just a red solution to a class and explaining that the solution contains gold nanoparticles can be disappointing as the red color can be obtained in many different ways without the need of nanoparticles. Something peculiar, like dichroism, can, on the other hand, shine the interest of an observer to the “nano-world”. Dichroic nanoparticles show different colors when illuminated from the front (scattering) or from the back (transmission). This effect is unique for nanoparticles and nanostructures in general and can generate the “WOW” effect in class or during public demonstrations. In this article we present a simple synthesis of dichroic silver and gold nanoparticles. Solutions of such nanoparticles are a stunning visual media for demonstrations, outreach and engaging audience in the “nano”world.

In this study, we analyzed angular-selective absorption in a guest&ndash, host liquid crystal (GHLC) cell for its application in smart windows. For reducing the energy consumption, angular-selective absorption is desired because the light transmitted through windows during the daytime is predominantly incident obliquely from direct sunlight. Owing to the absorption anisotropy of guest dichroic dyes, a GHLC cell can absorb the obliquely incident light, while allowing people to see through windows in a normal view. Therefore, the cell can provide a comfortable environment for occupants, and reduce the energy required for cooling by blocking the solar heat incident from the oblique direction. The GHLC cell can be switched between the transparent and opaque states for a normal view. The rising (falling) time was 6.1 (80.5) ms when the applied voltage was 10 V.

Isotope selective optical excitation of atoms is important for experiments with neutral atoms, metrology, and work with trapped ions, including quantum information processing. Polarization-enhanced absorption spectroscopy is used to frequency stabilize a tunable external cavity laser diode system at 398.9 nm for isotope selective photoionization of neutral Yb atoms. This spectroscopy technique is used to measure isotope resolved dispersive features from transitions within a see-through configuration ytterbium hollow-cathode discharge lamp. This Doppler-free dichroic polarization spectroscopy is realized by retro-reflecting a laser beam through the discharge and analyzing the polarization dependent absorption with balanced detection. The spectroscopy signal is recovered using lock-in detection of frequency modulation induced by current modulation of the external cavity laser diode. Here, we show an order of magnitude improvement in the long-term stability using polarization-enhanced absorption spectroscopy of Yb compared to polarization spectroscopy.

Gold nanoparticles depending on their shape and mixtures of multiple shapes can exhibit peculiar optical properties, including the dichroic effect typical of the Lycurgus cup, which has puzzled scientists for a long time. Such optical properties have been recently exploited in several fields such as paint technology, sensors, dichroic polarizers, display (LCD) devices, laser applications, solar cells and photothermal therapy among others. In this article, we have demonstrated a simple room temperature one-pot synthesis of gold sol displaying a dichroic effect using a slow reduction protocol involving only trisodium citrate as a reducing agent. We found that the dichroic gold sol can be easily formed at room temperature by reducing gold salt by trisodium citrate below a certain critical concentration. The sol displayed an orangish-brown color in scattered/reflected light and violet/blue/indigo/purple/red/pink in transmitted light, depending on the experimental conditions. With minor changes such as the introduction of a third molecule or replacing a small amount of water in the reaction mixture with ethanol, the color of the gold sol under transmitted light changed and a variety of shades of red, pink, cobalt blue, violet, magenta and purple were obtained. The main advantage of the proposed method lies in its simplicity, which involves the identification of the right ratio of the reactants, and simple mixing of reactants at room temperature with no other requirements. TEM micrographs displayed the formation of two main types of particles viz. single crystal gold nanoplates and polycrystalline faceted polyhedron nanoparticles. The mechanism of growth of the nanoplates and faceted polyhedron particles have been described by an enhanced diffusion limited aggregation numerical scheme, where it was assumed that both trisodium citrate and the gold ions in solution undergo a stochastic Brownian motion, and that the evolution of the entire system is regulated by a principle of energy minimization. The predictions of the model matched with the experiments with a good accuracy, indicating that the initial hypothesis is correct.

We study systematic effects from half-wave plates (HWPs) for cosmic microwave background (CMB) experiments using full-sky time-domain beam convolution simulations. Using an optical model for a fiducial spaceborne two-lens refractor telescope, we investigate how different HWP configurations optimized for dichroic detectors centred at 95 and 150 GHz impact the reconstruction of primordial B-mode polarization. We pay particular attention to possible biases arising from the interaction of frequency-dependent HWP non-idealities with polarized Galactic dust emission and the interaction between the HWP and the instrumental beam. To produce these simulations, we have extended the capabilities of the publicly available beamconv code. To our knowledge, we produce the first time-domain simulations that include both HWP non-idealities and realistic full-sky beam convolution. Our analysis shows how certain achromatic HWP configurations produce significant systematic polarization angle offsets that vary for sky components with different frequency dependence. Our analysis also demonstrates that once we account for interactions with HWPs, realistic beam models with non-negligible cross-polarization and sidelobes will cause significant B-mode residuals that will have to be extensively modelled in some cases.

The Star-Planet Activity Research CubeSat (SPARCS) is a 6U CubeSat under construction that is devoted to the photometric monitoring of M stars in the far-UV (FUV) and near-UV (NUV), to measure the time-dependent spectral slope, intensity and evolution of low-mass star high-energy radiation. We report on the progress made in the assembly, integration and test of the instrument payload at Arizona State University using a custom TVAC chamber and optical stimulus that provides calibration light sources and the custom contamination control environment that the FUV demands. The payload consists of a custom 90mm clear aperture telescope developed by Hexagon/Sigma Space, combined with a dichroic plate to separate the FUV and NUV beams developed by Teledyne Acton and Materion, married with twin focal plane array cameras separately optimized for their bandpasses as developed by JPL.

The Hector instrument is the new multi-object facility at the Anglo-Australian Telescope. It consists of new-format hexabundle IFU’s, complex robotic positioner with magnetic system, unique sky-fibre system, guiding system, optical cable and two spectrographs. Light is captured at the telescope prime focus by optical fiber imaging bundles (hexabundles) at f/3.25 and delivered to the spectrograph slit via ~50 m long fiber cable. At the spectrograph end, the fibers are reformatted into a curved slit relaying unconverted telescope input. The spectrograph optics includes fast collimators and cameras reimaging the slit onto 4k x 4k E2V detectors at f/1.3 with magnification 1/2.5. The challenge of good image quality with the large pupil size (180 mm) and the field of view (±12° at detector) was met by introduction of several aspheric surfaces in the all-refractive design. The blue and red arms, 372-591 nm and 571-778 nm, respectively, are implemented with the help of a dichroic beam splitter in the diverging beam followed by a collimating doublet lens for each arm. An upgrade is possible to the infra-red arm with the help of an additional dichroic beam splitter. The dispersers are asymmetric VPH gratings with slanted fringes optimised for the passband of each arm. Optical performance of the dichroic beamsplitter and gratings has been confirmed and complemented by in-house metrology. The spectrograph throughput is predicted based on transmittance of materials and coatings.

As larger and larger telescopes continue to come online and become operational the demand for large optical coatings such as Anti-Reflection (AR) coatings, Band Pass (BP) filters (wide & narrow), mirrors and Dichroic Beamsplitters (DBS) continues to grow. Materion’s Large Area Optics (LAO) laboratory provides capabilities matched by few other facilities in the world. With a demonstrated capability up to 1.4M we provide high performance optical interference filters in sizes much larger than those previously available. All components of the Materion LAO lab were custom designed and built to Materion performance requirements, including a large spectrophotometer, deposition system and substrate cleaning station. All in an ISO 6/7 clean room environment. Previous and current efforts include items for Large Synoptic Survey telescope (LSST), Very Large telescope (VLT), Hyper Suprime Camera (HSC), Visible Tunable Filter (VTF), SkyMapper Telescope as well as many others. This poster intends to demonstrate Materion capability and expertise.