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A dual-band (mid- and long-wave infrared) polarization-selective plasmonic absorber was designed and numerically investigated. This absorber traps definite polarization light and reflects light that is perpendicular to the polarization direction. It is extremely sensitive to polarization angle and can keep robustness to oblique incidence. The extinction rate does not reduce when the incident angle is even near 80°and rate value keeps above 130 for both resonance peaks. The absorber can respond to mid- and long-wave infrared atmospheric windows simultaneously and achieve near-unity absorption at 3.3 μ m and 9.8 μ m for specific polarization under normal radiation. The resonance condition is tuned by altering the geometric design. Owing to its high absorptivity and fine polarization properties, the absorber combines the advantages of a light absorber and a polarizer, and can be utilized in an uncooled infrared polarization detector, which simplify the optical system design and avoid the polarization information reconstruction error caused by the misplacement between the polarizer and the pixel.

A compact, high extinction ratio TM-pass polarizer based on hollow hybrid plasmonic waveguide (HPW) is proposed and investigated. With the optimized tapered structure and plasmonics induced optical confinement, the incident transverse magnetic (TM) mode goes through the hollow HPW with relatively low loss, while the transverse electric (TE) mode is cut-off. For a compact 4 μ m long on-chip TM-pass polarizer, the extinction ratio is as high as 57.7 dB at the central wavelength 1550 nm. Benefiting from the hollow plasmonic structure, the corresponding propagation loss is only 0.145 dB/ μ m and the device exhibits large fabrication tolerance. In addition, the extinction ratio >34 dB and insertion loss

An inline fiber optic birefringence enhanced accelerometer (FOBEA) which applies one polarizer and a ten-meter high birefringence fiber wrapped on a transducer cylinder is proposed. Birefringence of polarized modes in panda polarization maintaining fiber (PMF) is enhanced by fiber coating and cylinders of different parameters. Accelerometers with copper cylinder (FOBEA-1) and polyurethane cylinder (FOBEA-2) are fabricated, the tested average sensitivities are 1.06rad/g (20-3800 Hz) and 16.97 rad/g (20-2000 Hz). The experimental results show the birefringence gain of FOBEA-1 is in good consistent with theoretical calculation of 1.07 and an additional birefringence gain of FOBEA-2 is 5.52 because the polyurethane cylinder works as fiber coating with the thickness of 1.21 mm. Temperature crosstalk is also investigated.

We propose a polarization modulator (PolM) -based optical vector network analyzer (OVNA) with extended measurement bandwidth. The combined use of the PolM, a polarization controller (PC) and a polarizer performs phase-and-intensity hybrid modulation of optical signal with double-sideband (DSB) modulation. The ratio between phase and intensity modulations is controlled by the PC, leading to different modulation formats. The frequency response of a device-under-test (DUT) can be obtained by processing the results of two measurements under two arbitrarily different modulation formats. The significance of this work lies in that the measurement of a DUT with bandpass response can be simply achieved, which is a huge challenge for the conventional single-sideband (SSB)-based OVNAs. In addition, the measurement bandwidth is doubled compared with the conventional SSB-based OVNA. Moreover, the PolM-based OVNA can avoid the bias drifting problem using conventional Mach–Zehnder modulator (MZM)-based scheme. The proposed method is theoretically and experimentally demonstrated. A proof-of-concept experiment is carried out and a DUT with bandpass response is successfully measured using the proposed scheme.

This paper presents a process for the fabrication of subwavelength bilayer metal wire grid polarizers and describes the performance characterization of polarizers that were produced using the proposed method. These polarizers have a period of 278 nm and were fabricated on flexible plastic substrates using nanoimprint lithography followed by an aluminum deposition process. Transmission efficiency in excess of 0.55 and an extinction ratio of more than 32 dB were achieved in the visible range when the aluminum layer thickness of the polarizer was 70 nm. When a polarization analyzer with a six-channel sensor prototype was tested, an average error of 0.2002°was obtained, with a maximum error of 1.105°and a standard deviation of 0.7255°. The proposed fabrication method will be suitable for many applications in optics, including the manufacture of compound eye structures.

We report a 1 × N hybrid radio frequency (RF) photonic splitter with arbitrary phase shift and amplitude ratio using a dual-polarization dual-parallel Mach Zehnder modulator (DP-DPMZM). The DP-DPMZM is properly set to generate an orthogonally polarized single-sideband (SSB) modulated optical signal. By controlling a polarization controller (PC) and a polarizer (Pol.) that cascaded behind the modulator, an RF photonic splitter with arbitrary phase and amplitude ratio can be realized. Compared with previous reported works, the proposed RF splitter can be operated in a wide bandwidth since no optical or electrical filters are involved. The proposed scheme is theoretically analyzed and experimentally verified.

We report the propagation properties of polarized terahertz (THz) waves in a liquid crystal (LC) cell with subwavelength metallic gratings to produce transmissive THz elements with electrical tunability. One-dimensional metallic gratings, which can be used both as transparent electrodes and linear polarizers in the THz regime, were fabricated on the quartz glass substrates of the LC cell. The substrates with and without the metallic grating showed almost identical transmission spectra for a linearly polarized THz wave whose electric field was parallel to the grating vector. We fabricated a 90 ∘ -twisted nematic LC cell using the two substrates with the metallic grating and examined its transmission spectra in the THz regime. During these measurements, we applied a voltage to the LC via the metallic gratings. We calculated in detail the transmission spectra and its voltage dependence based on the effective medium theory for subwavelength structures, the continuum theory of twisted nematic LCs, and the optical constants of the LC in the THz regime. The observed spectra agreed well with theoretical simulations. These results demonstrate that LC cells with subwavelength metallic gratings are useful as active THz elements in applications such as attenuators and polarization rotators.

We developed an interferometric system capable of generate four interferograms simultaneously with independent phase shifts employing modulation by polarization. The proposed system consists of three coupled interferometers: A polarized Mach–Zehnder interferometer (PMZI) which generates a primary pattern with crossed polarizations, coupled to two Michelson systems that serve as replicators of the primary pattern. In the proposed system, coupled three interferometers which generate four interference patterns with π /2 phase shifts. The four interference patterns can be detected simultaneously carrying a controllable phase shift by placing a linear polarizer in each replica obtained. To show the novelty and usage of the developed system on phase varying information temporal stability is presented and experimental results for static and dynamic variations.

In this paper, a novel scheme to employ one external polarization division multiplexing Mach–Zehnder Modulator (PDM-MZM) and one polarizer to generate millimeter-wave four-level pulse amplitude modulation (PAM4) signal is proposed without the usage of expensive and power hungry digital-to-analog converter (DAC). Firstly, we theoretically derive the generation conditions for the mm-wave PAM4 signal scheme. Based on this cost-effective scheme, 6 Gbaud PAM4 signal carried by 84 GHz millimeter-wave transmission over 15 km single-mode fiber (SMF-28) with only 0.5 dB power penalty without any CD compensation is experimentally demonstrated. Furthermore, VPI simulation software is employed to numerically simulate the mm-wave PAM4 signal generation and explore the influences of polarization rotation of the polarizer and direct current (DC)-Bias on the performance of generated W-band signals. In a word, it would be a promising scheme for future 5G short-reach intensity modulation and direct detection (IM/DD) system.

Active transverse electric and transverse magnetic pass polarizers with lengths of only 1.92 μ m and 5.95 μ m based on silicon waveguides and phase change material VO2 films are theoretically demonstrated. The optical characteristics of the polarizers are simulated by using finite difference mode simulation. By controlling the phase state of VO2 film, the polarizers can realize the regulation of TE and TM polarizations. The insertion losses of both polarizers are less than 2.2 dB in the insulating state. When trigger to the metallic state, the unwanted polarization attenuation exceeds 21.07 dB while insertion losses are kept below 0.71 dB at a center wavelength of 1550 nm. Both polarizers have a high extinction ratio in the operating bandwidth of 200 nm. This provides a new way for polarizers based on VO2 film and silicon waveguide.

A novel CMOS-compatible polarizer with tilted polarization angle is proposed and theoretically analyzed. It is the first time, to the best of our knowledge, that an on-chip polarizer with polarization angle other than 0°or 90°is investigated. The polarizer consists of a waveguide, a cladding etched trench and a metal strip. The trench and metal break the symmetry of the waveguide structure and rotate the polarization axes, while the metal also attenuates the specific polarization component. The proposed polarizer is comprehensively investigated from design to fabrication tolerance and 3 different cases with polarization angle 30°, 45°and 60°are demonstrated. The simulated results reveal that extinction ratio as large as 20 dB at 1550 nm can be achieved with excess loss as low as 1 dB, over 100 nm wavelength range. Furthermore, the Monte Carlo analysis shows the feasibility of the proposed polarizer in terms of practical fabrication.

An active transverse electric (TE) pass polarizer with ultra-low insertion loss (IL) is proposed based on asymmetrical directional coupler consisting of a silicon waveguide and a silicon hybrid waveguide with phase change material of Ge 2 Sb 2 Te 5 (GST). The tunability of the polarizers relies on the considerable change of the optical properties of the GST between the amorphous and crystalline phases. We numerically demonstrate a 5.5- μ m-long active polarizer has an ultra-high IL of above 28 dB for the unwanted transverse magnetic (TM) mode and the ultra-low IL of as little as 0.12 dB for TE mode with the crystalline phase of GST. When trigger to the amorphous phase, the device nearly exhibits transparent with the negligible IL for TE/TM mode. The proposed device possesses a broadband of ∼ 200 nm with a high extinction ratio (ER) as well as relative large fabrication tolerance.

An active optical switch based on polarization-tuned guided-mode resonance filter (GMRF) for the optical communication wave band is experimentally demonstrated. The proposed active optical switch consists of a linear polarizer, a twisted nematic liquid crystal (TN-LC) polarization rotator and a GMRF from top to bottom. Two fabricated optical switches exhibit high resonance peaks with wavelengths around 1310 and 1550 nm in the voltage-off status. In the voltage-on status, weak light signals without resonance peaks pass through the optical switches. Thus light signal can be tuned by controlling the applied voltage on the TN-LC of the optical switch.

A compact static birefringent spectral range enhanced Fourier transform imaging spectrometer (SEFTIS) is presented. The key component of the proposed SEFTIS is a new static dual-path birefringent interferometer formed by a polarizer, a Wollaston prism and a modified Glan–Taylor prism. Without any moving elements, it produces two independent interference patterns for two wavebands detections simultaneously, thereby providing at least twice the width of the original working spectral range. Compared with previous spectral range enhanced imaging spectrometers, the developed sensor highly reduces the complexity and alignment difficulty of the system. Theory and experimental prototype working in 400–1700 nm are described in detail.

The polarization transmission of bi-layer nanowire polarizer is analyzed physically by using equivalent medium theory and Fabry–Perot resonate theory. The principal of the two theories are explained briefly. The analyzation of grating period, duty cycle and metal height on polarization transmission can be also applied to other type of nanowire polarizers. The critical period of the grating is given. The effects of the grating parameters on polarization performance are analyzed systematically on physical level. The extraordinary optical transmission of TM and specially TE polarization light through bi-layer nanowire grating is analyzed. The analyzation of the polarization transmission mechanism will be helpful for the design and fabrication of the gratings with good polarization properties.

In this paper, we have proposed a chirped microwave waveform generation scheme with septupled carrier frequency and increased time-bandwidth product (TBWP) by using two cascaded optical polarization modulators (PolMs) and an interleaver (IL). In the scheme, the first PolM is driven by a radio frequency (RF) signal followed by an IL to generate orthogonally-polarized + 3rd and − 4th-order sidebands. Then the other PolM driven by a parabolic signal is used to introduce the parabolic phase difference between the two tones. Subsequently, a photodiode (PD) with an optical polarizer is used to beat the two orthogonally-polarized optical tones for generating the frequency septupled chirped microwave signal. In order to increase the TBWP, the parabolic signal is segmented into multi-pieces to increase the bandwidth of the generated signal; and phase encoding or stretching the parabolic signal is used to increase the temporal duration. Simulation results show that chirped microwave waveform with the carrier frequency of 70 GHz, bandwidth of 29.49 GHz, TBWP of 19859.40 is generated by dealing with the electrical parabolic driving signal, which matches well with the theoretical analysis. The generated linearly chirped signals with high-frequency and large-TBWP is expected to the range resolution and detection range when used in radar system.

In order to acquire the spatial polarization information in real time, a snapshot, mid-wave infrared, full-polarization-imaging system (SMWIFPIS) is proposed in this paper. Equal weight variance was used to optimize the polarization axis direction of the linear polarizer and the fast-axis azimuth angle of the wave plate in each channel to reduce the impact of the random intensity fluctuations in the infrared detector. A calibration method of the SMWIFPIS is proposed by investigating Fourier analysis method of a rotatable retarder fixed polarizer Stokes polarimeter (RRFPSP), which is used to improve the accuracy of polarization measurement. The calibration theory of the system is deduced. Finally, the correctness of the calibration method and the performance of the SMWIFPIS are proved by experiments. The experimental results show that the measurement accuracy of the SMWIFPIS is improved obviously through error calibration and compensation, which indicates that the effectiveness of the method is validated. The information measured by the SMWIFPIS is accurate.

A method is proposed for efficient, rotationally symmetric, tight mirror focusing of laser beams that is optimally matched to their thin-film linear-to-radial polarization conversion by a constant near-Brewster angle of incidence of the beams onto a polarizing element. Two optical systems and their modifications are considered that are based on this method and on the use of Toraldo filters. If focusing components of these systems operate in media with refractive indices equal to that of the focal region, they take the form of an axicon and an annular reflector generated by the revolution of an inclined parabola around the optical axis. Vectorial formulas for calculating the diffracted field near the focus of these systems are derived. Also presented are the results of designing a thin-film obliquely illuminated polarizer and a numerical simulation of deep UV laser beams generated by one of the systems and focused in an immersion liquid. The transverse and axial sizes of a needle longitudinally polarized field generated by the system with a simplest phase Toraldo filter were found to be 0.39 λ and 10.5 λ , with λ being the wavelength in the immersion liquid.

In this paper, an on-chip polarizer passing the transverse-magnetic mode and a polarization beam splitter are proposed. The polarizer achieves an extinction ratio exceeding 20 dB within a spectral range from 1500 nm to 1610 nm, and has a value of 24dB at 1550 nm with a coupling efficiency of 84%. By employing a specific wavelength of 1570 nm, the polarizer behaves as the polarization beam splitter with extinction ratio for the transverse-electric mode and the transverse-magnetic mode of 29dB and 24 dB, respectively. In addition, the coupling efficiency of 95.98% and 78.18% for above two polarizations, demonstrate that our approach has a potential to efficiently control coupling splitting ratio via silicon subwavelength grating.

A spectral pre-compensation method based on a novel polarization-encoded filter (PEF) with a single-pass configuration is proposed and investigated, which can support a broadband amplification in a high-gain Ti:Sapphire amplifier. The spectral filtering effect is realized by adopting cascaded half-wave plate, quarter-wave plate, quartz crystal and thin film polarizer in this novel filter. Jones calculus is used for theoretically analyzing the characteristics of the PEF. The theoretical analysis demonstrates the advantages of using the cascaded wave plates in the PEF. In the proof-of-principle experiment, we can observe that the use of a single-pass PEF before a high gain ( > 1 0 6 ) Ti:sapphire (Ti:Sa) regenerative amplifier (RA) can effectively suppress the spectral gain-narrowing effect. The full width at half maximum (FWHM) bandwidth of the amplified pulse increases from 16 nm to 43 nm, and the full bandwidth increases from 73 nm to 90 nm, respectively. After compression, the pulse duration is measured to be 26.9 fs. The PEF provides a practical and effective solution of suppressing the spectral gain-narrowing effect in high gain Ti:sapphire amplifiers.

The Y-type cavity tunable dual-wavelength laser (DWL) based on the Nd:GdVO4 and Nd:YVO4 crystals is demonstrated. The DWL consists of two end-pumped structures being joined by a polarizer and sharing one same output coupler. The two end-pumped structures generate the DWL beams at 1063 nm and 1064 nm with orthogonal polarizations, as well the two optical cavity lengths are 33 and 26 mm, respectively. The output powers of 1063 nm and 1064 nm laser linearly increase with the incident pump powers increasing, reach 598.73 mW and 601.04 mW with the corresponding slope efficiencies at 18.9% and 13.1%, where the incident pump powers are 7.11 and 6.86 W, respectively. The long term stability of output powers are measured less than 2.0% in 2 h. By independently adjusting the incident pump powers, the frequency separation of the DWL is tuned from 259.60 to 373.50 GHz, with the output power ratio from 0.08 to 13.77. Such a stable, tunable DWL is potential for optical terahertz waves generation.

The performances of devices based on two-dimensional (2D) materials are limited by their atomic thickness, which leads to ultraweak interactions between light and 2D materials and ultralow optical absorption. We propose an integrated all-fibre platform based on a side-polished fibre (SPF) and graphene/MoS2 (GM) film. A coated Au film can enhance the interaction between the transverse-magnetic-like (TM) mode and GM film owing to the light field confinement effect of the Au film. By coating the Au film, the light absorption by the GM film can be enhanced 4.25 times for the TM mode. Surprisingly, the GM film absorption in the transverse-electric-like (TE) mode is suppressed by the Au film. The coated Au film makes the all-fibre device, based on the GM film, a TE-passing polariser with an extinction ratio of 19.7 dB at 1550 nm, compared to an extinction ratio of 15.9 dB for the Au-film-coated SPF without GM film. The extinction ratio of the all-fibre device can be further increased by reducing the thickness of the Au film. These findings improve our understanding of the interaction between light and 2D materials and provide an effective method towards the development of polarisation-sensitive multi-functional all-fibre devices based on 2D materials.

We propose a novel optical asymmetric image encryption method based on amplitude reconstruction of elliptically polarized light, which is free from silhouette problem. The original image is analytically separated into two phase-only masks firstly, and then the two masks are encoded into amplitudes of the orthogonal polarization components of an elliptically polarized light. Finally, the elliptically polarized light propagates through a linear polarizer, and the output intensity distribution is recorded by a CCD camera to obtain the ciphertext. The whole encryption procedure could be implemented by using commonly used optical elements, and it combines diffusion process and confusion process. As a result, the proposed method achieves high robustness against iterative-algorithm-based attacks. Simulation results are presented to prove the validity of the proposed cryptography.

A novel multifold clock recovery structure with demultiplexing function based on a frequency-doubling optoelectronic oscillator (FD-OEO) incorporating a common commercial phase modulator (PM) is proposed and experimentally demonstrated. A special phase modulation is obtained thanks to polarization-sensitive feature of LiNbO 3 crystal of the PM. The special phase modulated signal is then split two parts connected by two pairs of polarization controllers (PCs) and polarizers to perform polarization interference and phase modulation to intensity modulation conversion. By controlling the PCs, the joint use of PC and polarizer in the loop is to guarantee an OEO with fundamental frequency self-oscillation, while the other outside of the OEO obtains frequency-doubled microwave signal at the output of the photodetector. Additionally, an optical filter can be inserted into the outside branch to only allow ± 2nd-order sidebands pass through and realize frequency quadrupling after beating at the PD. Therefore, a prescaled clock at 10 GHz, a line-rate clock at 20 GHz and a 40 GHz frequency-doubled clock can be extracted from the injection-locked OEO respectively when a 2 × 10 Gb ∕ s optical time division multiplexing (OTDM) data signal is injected. A twofold time division demultiplexing is demonstrated. Theoretical analysis is developed, which is validated by an experiment.

We theoretically analyze, a compact Bragg grating inscribed metal clad leaky ridge waveguide (MCLRW) as a refractive index sensor which can be integrated with other elements on a single chip. The grating is considered to be written in the photosensitive core. Using the quasi-TE mode of the structure, it is shown that a metal layer underneath the core enhances the evanescent field in the ambient region resulting in a significant increase in the ambient refractive index sensitivity. The obtained sensitivity and the figure of merit of the considered sensor structure are found to be almost 13–14 times higher than that of a ridge waveguide without any metal layer. Further, due to the higher modal loss of the quasi-TM mode, no in-line polarizer is required to assemble with the device. Effect of the loss due to metal layer on the peak reflectivity as well as bandwidth of the spectrum is also discussed.

The paper presents a novel design for terahertz (THz) free-space time domain electro-optic (EO) detection where the static birefringent phases of the two balanced arms are set close to zero but opposite to each other. Our theoretical and numerical analyses show this design has much stronger ability to cancel the optical background noise than both THz ellipsometer and traditional crossed polarizer geometry (CPG). Its optical modulation depth is about twice as high as that of traditional CPG, but about ten times as high as that of THz ellipsometer. As for the dynamical range, our improved design is comparable to the THz ellipsometer but obviously larger than the traditional CPG. Some experiments for comparing our improved CPG with traditional CPG agree well with the corresponding theoretical predictions. Our experiments also show that the splitting ratio of the used non-polarization beam splitter is critical for the performance of our design.

We show the possibility of selective polarization generation in an amplifying photonic crystal structure via the use of an embedded film of a sub-wavelength thickness with uniformly oriented metallic elongated nanoparticles chaotically distributed in the volume of a semiconductor. Such nanocomposite polarizer presents a uniaxial crystal with different values of dielectric permittivity components along and perpendicular to the polar axis of the nanoparticles. Dispersion of the dielectric permittivity of the nanocomposite is defined by the concentration and shape factor of the nanoparticles. Wavelength dependence of imaginary part of the nanocomposite permittivity possesses a resonance behavior resulting from plasmon resonance in nanoparticles. We show that this allows, depending on the relative orientation of the nanocomposite anisotropy axis and the polarization direction of the light, to achieve the mode discrimination of the photonic structure in the vicinity of a resonance of one of the permittivity components, where the absorption of the nanocomposite layer is maximal. Also we vary the parameters of the nanocomposite polarizer to obtain the optimal conditions of optical generation at the given wavelength.

A microwave photonic phase shifter based on dual-polarization Mach-Zehnder modulator (DPol-MZM) is proposed and experimentally demonstrated in this paper. A polarization multiplexed double sideband (DSB) signal is produced by a DPol-MZM. An optical bandpass filter (OBPF) follows after the DPol-MZM to filter out the optical carrier and one sideband. The polarization multiplexed signal is converted into a linear polarization light by a polarizer (Pol), and then beat at a photodiode (PD) to obtain the phase shifted signal. Experiments are carried out, and a continuous phase shift from −180° to 180° over a wide microwave frequency range of 10–33 GHz can be achieved by changing the polarization state using a polarization controller (PC). We also studied the spurious free dynamic range (SFDR) in the experiments. The features of this proposed phase shifter are large operation bandwidth, full-range 360° phase shift, and simple structure.

A novel (to our knowledge) type of single-polarization (SP) coupler based on a dual-core photonic band-gap fiber (PBF) is proposed. The effects of structure parameters on the performance of this coupler are studied numerically based on the full vector finite element method (FEM). Finally, an optimal design with a length of 0.377 mm at the wavelength of 1.55 µm is achieved, and its implication in PBF-based fiber ring resonator (FRR), the effect of angular misalignment on the SP coupler are analyzed as well. When the SP coupler is incorporated into a PBF-based FRR, it functions as the power splitter and the polarizer simultaneously, and can extinct the secondary eigenstate of polarization (ESOP) propagating in the FRR. The mode field of SP coupler can match with the polarization-maintaining (PM) PBF with ultra-low temperature sensitivity proposed in previous study, and an all PM-PBF based FRR can be established, which is of great significance in suppressing the temperature-related polarization fluctuation and improving the long-term stability for RFOG, and the SP coupler has high angular misalignment tolerance as well.

In this paper, a novel method has been proposed for increasing the extinction ratio of a plasmonic waveguide polarizer. Aluminum was coated in a 20-micron multi-strip pattern on the top of a SU-8 waveguide to excite the surface plasmons. The simulation and experimental results showed that the extinction ratio of the multi-strip polarizer was more than those of single-strip polarizers with the same total aluminum-coated length due to the coupling loss between the Al-coated and uncoated regions and also the scattering at the edge of metal. This polarizer was characterized over a wide range of wavelengths and showed the high extinction ratios of 46 dB and 26.8 dB at the wavelengths of 1550 nm and 980 nm, respectively.

We present a tactical-grade interferometric fiber optic (IFOG) based on integrated optical chip (IOC). The chip comprises a light source, a photodiode , a polarizer, a double Y-junction and a phase modulator. By using a small-diameter sensing coil, and a signal-detection circuit, an IFOG based on IOC is realized. This allows for a significant reduction in the IFOG’s size, weight, power consumption and cost (SWaP-C). Preliminary performance data of a gyro prototype exhibits 0.12 deg/h bias instability over 1000 min. For the first time, to our knowledge, tactical-grade IFOG is realized based on integrated optical components except fiber coil.

This paper proposes a dual-function polarizer based on hybrid metasurfaces of vanadium dioxide (VO2) and Dirac semimetals (DSs). VO2’s insulator-to-metal phase transition capability is utilized to switch between transmission and reflection polarization conversion without reoptimizing the structure. When VO2 is used as a dielectric, the polarization converter operates in transmission mode, achieving a polarization conversion ratio (PCR) of over 90% at 4.29–6.39 THz. For VO2 in the metallic phase, it achieves reflection-type polarization conversion within a 1.32 THz frequency width, with PCR close to 100% It is also capable of dual-excitation control via adjustment of the Fermi level of DSs and conductivity of VO2.

In this paper, we theoretically and experimentally report an achiral dual-band metasurface with linear birefringence. The unit cell of the achiral metasurface consists of non-twisted Q-shape metallic ring resonators with a stub breaking the rotational symmetry. Moreover, due to the presence of the stub, we find the proposed metasurface emits dual-band circularly polarized wave with low transmission loss and high polarization extinction for a normal incident y-direction linearly polarized wave. We also systematically investigate the dependence of the electromagnetic response of the proposed structure on the geometric parameters. It is hoped that the proposed simple, easily fabricated model of achiral metasurface can be used in further polarization control applications

We report an absorber in the mid-infrared regime by using stacked metal-dielectric grating structure. The simulation results show that the minimal absorption magnitude is larger than 0.8 in the broadband range for angles up to 60° for TM polarization (magnetic field is parallel to grating grooves). At the same time, absorption for TE polarization (electric field is parallel to grating grooves) is negligible. Furthermore, such broadband absorption for TM polarization can be tuned by shrinking or enlarging the grating parameters. This absorber is a good candidate for potential applications such as polarization detectors and polarizers.

International audience; In this paper,we present a novel procedure for the synthesis of a filter having an arbitrarily specified amplitude transmittance. The filter configuration consists of N birefringent stages placed between a polarizer and an analyzer, with each stage containing an identical section and a variable section. An additional variable section is placed in front of the analyzer. The synthesis procedure is based on the resolution of a generalized nonlinear equation system directly deducted from the Jones matrix formalism to determine the angles of each stage, the angle of the analyzer and the phase shifts of the variable sections. A typical example of a 6-stage birefringent filter having an arbitrarily non-symmetric amplitude transmittance is shown and the opto-geometrical parameters are given to demonstrate the efficiency of the proposed synthesis procedure. The results obtained show an excellent agreement with those developed in the literature

A highly sensitive measurement of the displacement of an interferometer mirror based on spectral interferometry and Vernier effect is proposed and demonstrated. The displacement measurement employs two interferometers in tandem, an interferometer represented by a combination of a polarizer, a birefrigent quartz crystal and an analyzer, and a Michelson interferometer. In the setup the Vernier effect is generated and the resultant channeled spectrum is with the envelope which shifts with the displacement of the interferometer mirror. We analyze the new measurement method theoretically and show that the sensitivity of the displacement measurement based on the wavelength interrogation is substantially increased in comparison to a standard method with a Michelson interferometer. We also demonstrate the realization of the measurement setup in which the position of the interferometer mirror is controlled via a closed-loop piezo positioning system. Experimental results show that the displacement measurement can reach a sensitivity of 264 nm/μm, which is substantially increased in comparison to −34 nm/μm reached for a standard measurement.

A novel type of laser operated polymer composites based on orthorhombic δ-Bi 1− x Nd x B 3 O 6 powders (where x =0.025÷0.100) was prepared. The powders were synthesized by means of polymeric precursor method through the citrate way. They were analyzed using XRD, and HRTEM methods, then embedded into polyvinyl alcohol (PVA) photopolymer. During solidification the additional DC-electric field alignment was carried out. The composite films with thickness up to 0.4 mm were studied using the Senarmont method at wavelength of CW He–Ne laser 633 nm with simultaneous application of the DC-electric field at 50 kHz frequency possessing rectangular symmetrical form. As a source of photoinducing beam we used polarized 1064 nm Nd:YAG laser radiation and its power density was varied using a Glan prism polarizer. The linear electrooptical (EO) effect measurements were carried out during and after Nd:YAG laser treatment at different temperatures. The laser stimulated EO effect was explored versus the Nd 3+ content and temperature. It was shown that the Nd 3+ ion content plays the crucial role in the observed EO effect efficiency. The contribution of the piezo-electrical and piezo-optical phenomena as well as phonons in the observed effects is discussed.