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• The application of DMD in two techniques of phase and amplitude modulation were summarized. • Three wavefront shaping techniques were summarized. • Four typical methods for improving the signal-to-noise ratio in PAWS were summarized. • Four methods that push the boundaries of the acoustical limit in PAWS were summarized. In recent years, wavefront shaping technology has made it possible to refocus scattered photons through turbid media. The utilization of photoacoustic signal as feedback for wavefront shaping offers non-invasive and deep-penetrating advantages, making it increasingly attractive in the field of biomedical research. However, due to the short decorrelation time of scattered light in living biological tissues, demonstrating the technique in vivo remains challenging. Digital Micromirror Devices (DMD) with their various modulation modes and high refresh rates hold great potential in addressing this challenge and have been widely employed in Photoacoustic Guided Wavefront Shaping (PAWS) applications. This paper presents the fundamental principles of using photoacoustic signal as feedback to guide wavefront shaping and highlights the advantages of PAWS in biological tissue imaging. Furthermore, a comparative analysis of three commonly used spatial light modulators in PAWS is provided, along with an overview of the three main techniques employed in wavefront shaping. Additionally, methods for improving the signal-to-noise ratio and imaging resolution in PAWS are summarized, followed by a discussion on potential future directions for this field. [ABSTRACT FROM AUTHOR]

• An innovative quaternary hybrid light modulation (QHLM) based projection display is proposed. • A quaternary spatial light modulator is constructed by illuminating two parallel digital micro-mirror devices (DMDs) with different light intensities. • The quaternary digit-plane decomposition and the pixel-level alignment of two DMDs are realized. • The prototype is designed and implemented to verify that the QHLM can achieve 16-bit projection at 220 fps. Conventional spatial light modulators (SLM) can only be used for projecting 8-bit or 10-bit images at normal frame rate. Therefore, commercial high dynamic range (HDR) displays typically focus on boosting the contrast while neglecting to raise the bit-depth. Existing methods for high bit-depth display generally rely on stacking two SLMs to modulate the outgoing beam twice, namely multiplicative modulation, resulting in many troubles such as low optical efficiency, difficulty in pixel-level alignment, and complex image rendering algorithm. In this paper, an innovative quaternary hybrid light modulation (QHLM) based projection display is proposed and realized. By illuminating two parallel digital micro-mirror devices (DMDs) with different light intensities, the quaternary digit-planes (QDs) with four gray levels are able to be modulated rapidly. Aiming at this ability, the quaternary pulse width modulation (QPWM) is incorporated with the quaternary light-intensity modulation (QLM) to fundamentally improve the modulation efficiency compared to the binary light modulation mode. Furthermore, the quaternary digit-plane decomposition (QDD) based image splitting algorithm is adopted to split a high bit-depth image into two images that drive two DMDs respectively. The prototype is designed and built to verify the feasibility of the QHLM based projection display. The experimental results demonstrate that the prototype can project 16-bit images at 220 fps. Through additive modulation of two DMDs in parallel, the QHLM entirely avoids the drawbacks of multiplicative modulation. As a completely different technology, the QHLM has a great potential for HDR projection applications. [ABSTRACT FROM AUTHOR]

Spatial light modulators (SLMs) are versatile devices used for optical studies. These instruments have a wide area of application in photonics. Additionally, SLMs have potential utility in different applications, such as biomedical applications, laser based surgery for precise cutting and as optical tweezers to separate cells in a petri container. However, the high cost of SLM devices prevents their widespread use in many areas, including industrial areas and scientific research laboratories. This paper demonstrates how to design a digital light processor (DLP) based low-cost SLM and describes how to obtain structured electromagnetic waves with the designed SLM. Therefore, this research was undertaken to design and produce a low-cost SLM device for optical applications. For this purpose, two prerequisites had to be fulfilled, the first was to use suitable components of a projection device with DLP-based digital micro-mirror device (DMD), and the second was to eliminate unnecessary SLM components from the system. Finally, holographic images reflected on the SLM screen were created by using Mathematica software program to change the amplitude and phase of the electromagnetic waves in order to obtain the structured electromagnetic waves. [ABSTRACT FROM AUTHOR]

Digital micro-mirror devices (DMDs) have been deployed in many optical applications. As compared to spatial light modulators (SLMs), they are characterized by their much faster refresh rates (full-frame refresh rates up to 32 kHz for binary patterns) compared to 120 Hz for most liquid crystal SLMs. DMDs however can only display binary, unipolar patterns and utilize temporal modulation to represent with excellent accuracy multiple gray-levels in display applications. We used the built-in time domain dynamic range representation of the DMD to project 8-bit complex-fields. With this method, we demonstrated 8-bit complex field modulation with a frame time of 38.4 ms (around 0.15 s for the entire complex-field). We performed phase conjugation by compensating the distortions incurred due to propagation through free-space and a scattering medium. For faster modulation speed, an electro-optic modulator was used in synchronization with the DMD in an amplitude modulation mode to create grayscale patterns with frame rate ~ 833 Hz with display time of only 1.2 ms instead of 38.4 ms for time multiplexing gaining a speed up by a factor of 32. [ABSTRACT FROM AUTHOR]

Digital micromirror devices (DMDs) are spatial light modulators that employ the electro-mechanical movement of miniaturized mirrors to steer and thus modulate the light reflected off a mirror array. Their wide availability, low cost and high speed make them a popular choice both in consumer electronics such as video projectors, and scientific applications such as microscopy. High-end fluorescence microscopy systems typically employ laser light sources, which by their nature provide coherent excitation light. In super-resolution microscopy applications that use light modulation, most notably structured illumination microscopy (SIM), the coherent nature of the excitation light becomes a requirement to achieve optimal interference pattern contrast. The universal combination of DMDs and coherent light sources, especially when working with multiple different wavelengths, is unfortunately not straight forward. The substructure of the tilted micromirror array gives rise to a blazed grating, which has to be understood and which must be taken into account when designing a DMD-based illumination system. Here, we present a set of simulation frameworks that explore the use of DMDs in conjunction with coherent light sources, motivated by their application in SIM, but which are generalizable to other light patterning applications. This framework provides all the tools to explore and compute DMD-based diffraction effects and to simulate possible system alignment configurations computationally, which simplifies the system design process and provides guidance for setting up DMD-based microscopes. This article is part of the Theo Murphy meeting 'Super-resolution structured illumination microscopy (part 1)'. [ABSTRACT FROM AUTHOR]

Flexible and fast control of the phase and amplitude of coherent light, enabled by digital micromirror devices (DMDs) and spatial light modulators, has been a driving force for recent advances in optical tweezers, nonlinear microscopy, and wavefront shaping. In contrast, engineering spatially partially coherent light remains widely elusive due to the lack of tools enabling a joint analysis and control sequence. Here, we report an approach to coherence engineering that combines a quasi-monochromatic, thermal source and a DMD together with a ptychographic scanning microscope. The reported method opens up new routes to low-cost coherence control, with applications in micromanipulation, nanophotonics, and quantitative phase contrast imaging. [ABSTRACT FROM AUTHOR]

We present an experimental off-axis optical holographic scheme employing a digital micromirror device (DMD) as projecting media instead of a liquid crystal spatial light modulator (SLM). The DMD allows projecting information through light reflection. We perform holographic recording in the Fourier and the Fresnel domains under similar experimental configurations to test our experimental scheme and verify the DMD performance as a binary amplitude SLM. For the digital holographic recovery process of Fourier holograms, we applied a non-linear modification that allows reducing the degradation in the recovered data. We also implement a multiplexing protocol enabling the packaging of an entire holographic dynamic scene into a single data. Furthermore, we use QR codes as information containers to achieve noise-free information recovery after holographic reconstruction. Experimental results demonstrate the viability and versatility of a DMD in an experimental holographic scheme. [ABSTRACT FROM AUTHOR]

In recent times, spatial light modulators have become a common tool in optics laboratories as well as industrial environments for shaping the spatial structure of a light beam. Although these devices are often easy to use, their high cost has limited their use in many undergraduate laboratories. However, in recent years the progress in developing more cost-effective projectors has led to affordable spatial light modulators in the form of so-called Digital Micromirror Devices (DMD). This reduction in price, as well as their simple employment, make such devices increasingly suitable for use in undergraduate instructional laboratories to demonstrate optical effects and the shaping of light fields. Here, we show one of the most cost-effective ways to make a DMD available, namely, turning a projector evaluation module into a computer-controlled spatial light modulator. We explain the underlying functioning and how this low-cost spatial light modulator can be used in undergraduate laboratories. We further characterize the efficiency of the device for the most commonly used laser wavelengths and demonstrate various exemplary optics experiments suitable for undergraduate laboratories ranging from single and multi-slit diffraction to optical Fourier transformations. Finally, we show that by using amplitude holography, the device can generate transverse spatial modes, e.g., Laguerre-Gaussian beam, which are one of the most commonly used spatially structured beams. [ABSTRACT FROM AUTHOR]

There is an ongoing technological revolution in the field of biomedical instruments. Consequently, high performance healthcare devices have led to remarkable economic developments in the medical hardware industry. Until now, nearly all optical bio-imaging systems are based on the 2-dimensional imaging chip architecture. In fact, recent developments in digital micromirror devices (DMDs) are gradually making their way from conventional optical projection displays into biomedical instruments. As an ultrahigh-speed spatial light modulator, the DMD may offer a range of new applications including real-time biomedical sensing or imaging, as well as orientation tracking and targeted screening. Given its short history, the use of DMD in biomedical and healthcare instruments has emerged only within the past decade. In this paper, we first provide an overview by summarizing all reported cases found in the literature. We then critically analyze the general pros and cons of using DMD, specifically in terms of response speed, stability, accuracy, repeatability, robustness, and degree of automation, in relation to the performance outcome of the designated instrument. Particularly, we shall focus our discussion on the use of Micro-Electro-Mechanical System (MEMS)-based devices in a set of representative instruments including the surface plasmon resonance biosensor, optical microscopes, Raman spectrometers, ophthalmoscopes, and the micro stereolithographic system. Finally, the prospects of using the DMD approach in biomedical or healthcare systems and possible next generation DMD-based biomedical devices are presented. [ABSTRACT FROM AUTHOR]

The non-separability between the spatial and polarization Degrees of Freedom (DoF) of complex vector light fields has drawn significant attention in recent times. Key to this is its remarkable similarities with quantum entanglement, with quantum-like effects observed at the classical level. Crucially, this parallelism enables the use of quantum tools to quantify the coupling between the spatial and polarization DoFs, usually implemented with polarization-dependent spatial light modulators, which requires the splitting of the vector mode into two orthogonal polarization components. Here, we put forward an alternative approach that relies on the use of Digital Micromirror Devices (DMDs) for a fast, cheap, and robust measurement, while the polarization-independent nature of DMDs enables a reduction in the number of required measurements by 25%. We tested our approach experimentally on cylindrical vector modes with arbitrary degrees of non-separability, of great relevance in a wide variety of applications. Our technique provides a reliable way to measure in real time the purity of vector modes, paving the way for a wide variety of applications where the degree of non-separability can be used as an optical sensor. [ABSTRACT FROM AUTHOR]

The results of the laboratory experiments are presented for synthesis of the I m -Bessel correlated beams by a Spatial Light Modulator (SLM) and a Digital Micromirror Device (DMD) as well as for their interactions with atmospheric turbulence simulated by either an SLM or a mixed-air turbulent chamber. The synthesis procedure of these beams relies on the incoherent superposition of their coherent modes being Laguerre-Gaussian (LG) functions having a variable radial mode and a fixed azimuthal mode carrying the Orbital Angular Momentum (OAM). As a result of such construction the correlation functions of these random beams have separable phase carrying the OAM with the index inherited from the coherent modes. The coherence states of these beams are controlled by the distribution of weights of the coherent modes in superposition, varying from perfectly coherent to nearly incoherent. We explore the effects of the cycling rates of the SLM and the DMD used for source synthesis on the average intensity and the scintillation index of the generated beams having different OAM indices and coherence states after propagation in atmospheric turbulence. Our analysis indicates that for fairly incoherent beams with sufficiently large OAM index and high cycling rates the atmospheric turbulence can be efficiently mitigated. [ABSTRACT FROM AUTHOR]

Advances in consumer display screen technologies have historically been adapted by researchers across the fields of optics as they can be used as electronically controlled spatial light modulators (SLMs) for a variety of uses. The performance characteristics of such SLM devices based on liquid crystal (LC) and digital micromirror device (DMD) technologies, in particular, has developed to the point where they are compatible with increasingly sensitive instrumental applications, for example, Raman spectroscopy. Spatial light modulators provide additional flexibility, from modulation of the laser excitation (including multiple laser foci patterns), manipulation of microscopic samples (optical trapping), or selection of sampling volume (adaptive optics or spatially offset Raman spectroscopy), to modulation in the spectral domain for high-resolution spectral filtering or multiplexed/compressive fast detection. Here, we introduce the benefits of different SLM devices as a part of Raman instrumentation and provide a variety of recent example applications which have benefited from their incorporation into a Raman system. [ABSTRACT FROM AUTHOR]

An ultrafast spectrum programmable femtosecond laser may enhance the performance of a wide variety of scientific applications, e.g., multi-photon imaging. In this paper, we report a digital micromirror device (DMD)-based ultrafast pulse shaper, i.e., DUPS, for femtosecond laser arbitrary amplitude shaping — the first time a programmable binary device reported to shape the amplitudes of ultrafast pulses spectrum at up to 32 kHz rate over a broad wavelength range. The DUPS is highly efficient, compact, and low cost based on the use of a DMD in combination with a transmission grating. Spatial and temporal dispersion introduced by the DUPS is compensated by a quasi-4-f setup and a grating pair, respectively. Femtosecond pulses with arbitrary spectrum shapes, including rectangular, sawtooth, triangular, double-pulse, and exponential profile, have been demonstrated in our experiments. A feedback operation process is implemented in the DUPS to ensure a robust and repeatable shaping process. The total efficiency of the DUPS for amplitude shaping is measured to be 27%. [ABSTRACT FROM AUTHOR]

We have proposed an approach for rapid generation of perfect vortex beam without side lobes through a digital micromirror device (DMD). Employing this method, the amplitude and phase of far field can be controlled indirectly by changing the rotation state of each unit on the DMD. The perfect vortex beams of equal rings diameter independent of their topological charges are generated commendably and the side lobes are avoided. Moreover, we have demonstrated rapid switching among the generated orbital angular momentum modes at the speed of 10 kHz, which is much faster than that of the usual method realized by spatial light modulators (SLMs). The proposed method is very beneficial for the optical communication and trapping or manipulating the small particle based on orbital angular momentum modes. [ABSTRACT FROM AUTHOR]

Large angle, nonmechanical beam steering is demonstrated at 4.62 µm using the digital light processing technology. A 42-deg steering range is demonstrated, limited by the field-of-view of the recollimating lens. The measured diffraction efficiency is 8.1% on-axis and falls-off with a sin² dependence with the steering angle. However, within the 42-deg steering range, the power varied less than 25%. The profile of the steered laser beam is Gaussian with a divergence of 5.2 mrad. Multibeam, randomly addressable beam steering, is also demonstrated. [ABSTRACT FROM AUTHOR]

We demonstrate a simple illumination system based on a digital mirror device which allows for fine control over the power and pattern of illumination. We apply this to localization microscopy (LM), specifically stochastic optical reconstruction microscopy (STORM). Using this targeted STORM, we were able to image a selected area of a labelled cell without causing photo-damage to the surrounding areas of the cell. [ABSTRACT FROM AUTHOR]

[Display omitted] • The PEGMA brushes with arbitrary complex structures were fabricated via DMD-modulated Photo-ATRP reaction. • The growth of patterned PEGMA brushes could be regulated by adjusting the DMD light modulation parameter. • A functional surface with hydrophilic contrast was created. • The good selective BSA protein adsorption ability of the PEGMA brushes patterned surface allow the protein patterns with customized geometric feature were achieved. In the present work, programmable light pattern produced by digital micro-mirror device (DMD) spatial light modulator was employed to initiate the atom transfer radial polymerization (ATRP) for fabricating the patterned polymer brushes on the silicon substrate surface. Results from a series of characterization methods such as optical microscopy, 3D optical surface profiler, and X-ray photoelectron spectroscopy proved the poly (ethylene glycol) methyl acrylate (PEGMA) brushes with complex structures were successfully generated. The thickness of PEGMA brushes could be regulated by adjusting the DMD light modulation parameter including pattern size, gray value and exposure time. The contact angle measurements showed the PEGMA brushes could improve the hydrophilicity property of substrate surface. The antifouling property of the patterned surfaces with different shapes were tested, and the results indicated that the PEGMA brushes could effectively resist the adhesion of bovine serum albumin (BSA) protein, leading to the selective arrangement of protein. The reported method for generating the polymer brush patterns shows great potential for the manipulation of surface property in facilitating a range amount of applications from anti-biofouling coating, interface lubrication to biomimetic and smart surfaces. [ABSTRACT FROM AUTHOR]

The digital micromirror devices (DMDs) are widely used in various DLP® products. Since the DMDs were the first optical MEMS in mass production when Texas Instruments introduced the DMD-based digital display products to the market in 1996, there were no existing characterization tools and methods that could meet the specific needs of the DMDs. New characterization tools had to be built and methodologies had to be developed to fully assess the performance and robustness of the devices. Over the years, new commercial MEMS characterization tools have become available and some were adopted for DMD characterization. However, characterizing devices with millions of mirrors still remains challenging and requires unique solutions. In this paper, current static, dynamic, and optical characterization methods and tools used for DMD characterization will be presented. The array-based tilt angle measurement method using far-field diffraction patterns and the device-based operating space evaluation will be discussed in detail. [ABSTRACT FROM AUTHOR]

A digital micromirror device (DMD) acts as a spatial light modulator in a maskless photolithography system. Illuminated by coherent light, DMD performs as a two-dimensional diffraction grating because of its periodical internal structure. Diffraction efficiency is an important factor for evaluating the exposure doses. A diffraction model of DMD based on Fourier analysis demonstrates that errors of the DMD's manufacture and the precision of the machining of the optical mechanical structure affect the diffraction efficiency. Additionally, analysis of exposure results by the diffraction model of DMD in Tracepro explains the degradation of the exposure quality and is helpful for calibrating the direction of optical focusing. [ABSTRACT FROM AUTHOR]

• Digital micromirror device functions as both spatial and spectral modulator. • The experimental spectral resolution is 3.73 nm over the visible spectrum. • Real-time spectral video with a frame-rate up to 10Hz with compressive sampling. • With the potential to be easily extended to both ultraviolet and infrared. Spectral imaging technique, which retrieves both spatial and spectral information of a scene or an object, is an important tool in applications such as food inspection, vegetation monitoring and geographic remote sensing. Most spectral imaging systems have a complex system architecture, in which different components are used for different functions, limiting the efficiency of information retrieval. Here, we propose a hyperspectral imaging system with a simple architecture, where a multiplexing digital micromirror device functions both as a spatial light modulator for spatial imaging and a diffractive grating for spectral measuring simultaneously. The proof-of-principle system contains a group of lenses, a digital micromirror device and a one-dimensional detector array, and is capable of performing 128 × 128 pixel resolution hyperspectral imaging over the visible spectrum with an experimental 3.73 nm spectral resolution. Furthermore, by using a compressive sampling strategy, continuous real-time spectral video is performed with a frame-rate up to 10 Hz. The concise architecture of the proposed system, with the potential to be easily extended to both ultraviolet and infrared, offers an alternative scheme to manufacture low-cost, compact, hyperspectral imagers. [ABSTRACT FROM AUTHOR]

Visual inspection for a highly reflective surface is commonly faced with a serious limitation, which is that useful information on geometric construction and textural defects is covered by a parasitic image due to specular highlights. In order to solve the problem, we propose an effective method for removing the parasitic image. Specifically, a digital micromirror device (DMD) camera for programmable imaging is first described. The strength of the optical system is to process scene ray before image formation. Based on the DMD camera, an iterative algorithm of modulated region selection, precise region mapping, and multimodulation provides removal of the parasitic image and reconstruction of a correction image. Finally, experimental results show the performance of the proposed approach. [ABSTRACT FROM AUTHOR]

Spatial light modulators (SLMs) have shown to be versatile tools for displays, but also for various applications in optical metrology since light can be individually directed and customized and thus they may serve as flexible masks or holograms. In contrast to SLMs based on liquid crystal on silicon or liquid crystal displays (LCDs), which allow tailoring phase and/or amplitude of a wavefront in transmission or reflection, digital micromirror devices (DMDs) offer highest reflectivity and allow precise as well as fastest guidance of light rays based on the fundamental reflection law. Here, we present and compare different approaches for simulating the diffractive pattern when applying a micromirror device for wavefront readout. The different simulation methods for calculating the diffraction pattern are based on Monte-Carlo simulations in combination with nonsequential ray tracing, on Fourier optics methods (Fourier transform, FT) and on complex digital holographic wavefront propagation. The wavefront measurement concept with the DMDs is based on selecting single subapertures of the wavefront under test and on measuring the wavefront slope consecutively in a scanning procedure. In contrast, in LCD-based approaches already shown in literature, the selection of subapertures and thus the scanning procedure is performed in transmission. The measurement concept and diffraction-based measurement errors of this method will be demonstrated for aspheric optics. Furthermore, different approaches for the prediction and reduction of the diffractive pattern--also based on holographic complex wave front propagation--will be described and characterized. [ABSTRACT FROM AUTHOR]

Commercial digital multimirror devices offer a cheap and effective alternative to more expensive spatial light modulators for ablation via beam shaping. Here we present femtosecond laser ablation using the digital multimirror device from an Acer C20 Pico Digital Light Projector and show ablation of complex features with feature sizes ranging from sub-wavelength (400 nm) up to ~30 µm. Simulations are presented that have been used to optimize and understand the experimentally observed resolution. [ABSTRACT FROM AUTHOR]

A homogeneous one-dimensional optical lattice is demonstrated by using a high-precision beam shaper based on a digital micro-mirror device (DMD) with an imaging system containing a pinhole low-pass filter (LPF). This system is capable of producing a high-quality flattop beam profile to form a standing-wave optical lattice with a 50 x 50 µm² flattop region. The periodic potential generated by the optical lattice confines ultracold atoms in Bose-Einstein condensate experiments. We conducted beam shaping tests at several wavelengths by implementing various coherent and incoherent light sources in the visible and infrared wavelength ranges. Experiments produced flattop and other well-controlled beam profiles with 0.2% to 0.26% root-mean-square (RMS) error after applying a digital LPF and nearly flat phase. Several concerns for the system design are presented. First, the energy requirement was determined by power conversion analysis and DMD diffraction efficiency simulation. In addition, a LabVIEW program was written to accelerate the speed of the iterative process for beam profile refinement. Finally, various camera calibrations improved the measurement accuracy. We achieved a 1.25% RMS error flattop beam with diameter of 70.4 µm at the atoms' plane. Other beam profile measurements in different diagnostic planes demonstrated a good intensity uniformity of the optical lattice. [ABSTRACT FROM AUTHOR]

In this contribution, we present a high-speed, multiplex, grating spectrometer based on a spectral coding approach that is founded on principles of compressive sensing. The spectrometer employs a single-pixel InGaAs detector to measure the signals encoded by an amplitude spatial light modulator (digital micromirror device, DMD). This approach leads to a speed advantage and multiplex sensitivity advantage atypical for standard dispersive systems. Exploiting the 18.2 kHz pattern rate of the DMD, we demonstrated 4.2 ms acquisition times for full spectra with a bandwidth of 450 nm (5250–4300 cm−1; 1.9–2.33 µm). Due to the programmability of the DMD, spectral regions of interest can be chosen freely, thus reducing acquisition times further, down to the sub-millisecond regime. The adjustable resolving power of the system accessed by means of computer simulations is discussed, quantified for different measurement modes, and verified by comparison with a state-of-the-art Fourier-transform infrared spectrometer. We show measurements of characteristic polymer absorption bands in different operation regimes of the spectrometer. The theoretical multiplex advantage of 8 was experimentally verified by comparison of the noise behavior of the spectral coding approach and a standard line-scan approach. [ABSTRACT FROM AUTHOR]

• Encoding redundancy found in superpixel complex-amplitude modulation with a DMD • Novel data hiding scheme in the DMD binary pattern without extra cost • No damage to the original light field information after a lot of data is embedded • Favorable for copyright protection and secure data sending in holographic display A digital micromirror device (DMD) is conventionally an amplitude-type binary spatial light modulator. However, the complex-amplitude light modulation with a DMD can be achieved using a superpixel scheme. In the superpixel scheme, we notice that multiple different DMD local block patterns may correspond to the same complex-amplitude superpixel value. Based on this inherent encoding redundancy, a large amount of external data can be embedded into the DMD pattern without extra cost. Meanwhile, the original complex light field information carried by the DMD pattern is fully preserved and almost no quality degradation will be caused by the embedded data. This proposed data hiding or watermarking scheme is favorable for applications such as secure information transmission and copyright protection in holographic display. [ABSTRACT FROM AUTHOR]

We present spatial coherence measurements of partially coherent light in the far-field of incoherent sources with an experimental setup based on the Thompson–Wolf and Partanen–Turunen–Tervo experiments, to be performed in the context of a possible solar coherence measurement space instrument. The optical setup consists of a telescope to collimate light from a source, to diffract it by a digital micromirror device implementing a Young double-aperture interferometer in retroreflection mode, and finally to image the source into a two-dimensional sensor. Two multimode optical fibers with different diameters were used as incoherent sources and the results obtained for the spectral degree of coherence are compared to those expected from the van Cittert–Zernike theorem. [ABSTRACT FROM AUTHOR]

We present spatial coherence measurements of partially coherent light in the far-field of incoherent sources with an experimental setup based on the Thompson–Wolf and Partanen–Turunen–Tervo experiments, to be performed in the context of a possible solar coherence measurement space instrument. The optical setup consists of a telescope to collimate light from a source, to diffract it by a digital micromirror device implementing a Young double-aperture interferometer in retroreflection mode, and finally to image the source into a two-dimensional sensor. Two multimode optical fibers with different diameters were used as incoherent sources and the results obtained for the spectral degree of coherence are compared to those expected from the van Cittert–Zernike theorem. [ABSTRACT FROM AUTHOR]

Digital micromirror devices (DMDs) have become ubiquitous as spatial light modulators in the optics community, but ambiguity remains on how best to implement them in a laboratory environment. Here, we explicitly tackle the problem of generating high fidelity modes of structured light while maintaining optical efficiency. We present a theoretical characterization of the diffractive properties of the DMD, allowing us to motivate an alignment procedure that improves optical efficiency. We also present a set of best practice recommendations that cover aspects of DMD operation that are not immediately intuitive, these best practice recommendations ensure structured light is generated with the correct spatial profile and wavefront. We present experimental results that show efficiency improvements of up to 20%. Further, we demonstrate the creation of modes of structured light with fidelities in excess of 96%. The best practices presented here provide a pragmatic set of procedures for ensuring DMDs are used to their fullest potential. [ABSTRACT FROM AUTHOR]