Abstract: We report on lenses that operate over the visible wavelength band from 450 nm to beyond 700 nm, and other lenses that operate over a wide region in the near-infrared from 650 nm to beyond 1000 nm. Lenses were recorded in liquid crystal polymer layers only a few micrometers thick, using laser-based photoalignment and UV photopolymerization. Waveplate lenses allowed focusing and defocusing laser beams depending on the sign of the circularity of laser beam polarization. Diffraction efficiency of recorded waveplate lenses was up to 90% and contrast ratio was up to 500:1.

Abstract: Planar metasurface based quarter-wave plates offer various advantages over conventional waveplates in terms of compactness, flexibility and simple fabrication; however they offer very narrow bandwidth of operation. Here, we demonstrate a planar terahertz (THz) metasurface capable of linear to circular polarization conversion and vice versa in a wide frequency range. The proposed metasurface is based on horizontally connected split ring resonators and is realized on an ultrathin (0.05λ) zeonor substrate. The fabricated quarter waveplate realizes linear to circular polarization conversion in two broad frequency bands comprising 0.64–0.82 THz and 0.96–1.3 THz with an insertion loss ranging from −3.9 to −10 dB. By virtue of ultrathin sub wavelength thickness, the proposed waveplate design is well suited for application in near field THz optical systems. Additionally, the proposed metasurface design offers novel transmission phase characteristics that present further opportunities to realize dynamic polarization control of incident waves.

Abstract: We propose to use a super-structured waveplate (called an S-waveplate) for vectorial optical vortex filtering, and experimentally demonstrate the radial Hilbert transform and selective edge enhancement. Based on the Jones calculus of polarization states and Fourier analysis, we calculate and analyze the point spread function of an optical 4-f system including an S-waveplate filter having the vectorial vortex of topological charge 1 (TC = 1). Numerical simulations and optical experiments demonstrate that a vectorial optical vortex filter can be used to implement selective edge enhancement with an analyzer before the output plane. The edge enhancement can be obtained even when the center of the filter is off-axis or the illuminating light is non-monochromatic.

Abstract: We describe the development of an ambient-temperature continuously-rotating half-wave plate (HWP) for study of the Cosmic Microwave Background (CMB) polarization by the POLARBEAR-2 (PB2) experiment. Rapid polarization modulation suppresses 1/f noise due to unpolarized atmospheric turbulence and improves sensitivity to degree-angular-scale CMB fluctuations where the inflationary gravitational wave signal is thought to exist. A HWP modulator rotates the input polarization signal and therefore allows a single polarimeter to measure both linear polarization states, eliminating systematic errors associated with differencing of orthogonal detectors. PB2 projects a 365-mm-diameter focal plane of 7,588 dichroic, 95/150 GHz transition-edge-sensor bolometers onto a 4-degree field of view that scans the sky at ~ 1 degree per second. We find that a 500-mm-diameter ambient-temperature sapphire achromatic HWP rotating at 2 Hz is a suitable polarization modulator for PB2. We present the design considerations for the PB2 HWP, the construction of the HWP optical stack and rotation mechanism, and the performance of the fully-assembled HWP instrument. We conclude with a discussion of HWP polarization modulation for future Simons Array receivers.

Abstract: Planar periodic plasmonic structures encased in a magnetic host revealed an unexpected polarization transformation. In the proposed thin periodic gold–garnet layer, the near fields strongly modify (enhance) the magneto-optical response of garnet. We show that the configuration of near fields in the magnetized layer can be engineered so that the layer converts the linear polarization to elliptical (or circular) or rotates the plane of polarization over a large angle in the transmission (or Faraday) geometry. Since the helicity of elliptically (circularly) polarized light (or the polarization rotation angle) is altered by reversing the magnetization of garnet, the considered plasmonic structure acts as a tunable wave plate.

Abstract: We proposed spectroscopic ellipsometry employing dual-optical-comb spectroscopy. We demonstrated the ellipsometric evaluation of a high-order quarter waveplate and a SiO 2 thin film standard with the spectral resolution of 48 MHz.

Abstract: We describe the development of an ambient-temperature continuously-rotating half-wave plate (HWP) for study of the Cosmic Microwave Background (CMB) polarization by the POLARBEAR-2 (PB2) experiment. Rapid polarization modulation suppresses 1/f noise due to unpolarized atmospheric turbulence and improves sensitivity to degree-angular-scale CMB fluctuations where the inflationary gravitational wave signal is thought to exist. A HWP modulator rotates the input polarization signal and therefore allows a single polarimeter to measure both linear polarization states, eliminating systematic errors associated with differencing of orthogonal detectors. PB2 projects a 365-mm-diameter focal plane of 7,588 dichroic, 95/150 GHz transition-edge-sensor bolometers onto a 4-degree field of view that scans the sky at $\sim$ 1 degree per second. We find that a 500-mm-diameter ambient-temperature sapphire achromatic HWP rotating at 2 Hz is a suitable polarization modulator for PB2. We present the design considerations for the PB2 HWP, the construction of the HWP optical stack and rotation mechanism, and the performance of the fully-assembled HWP instrument. We conclude with a discussion of HWP polarization modulation for future Simons Array receivers.

Abstract: A Au nanofin array embedded in SiO2 was designed and fabricated to achieve an achromatic half waveplate with high transmittance at visible wavelengths. On the basis of the waveguide theory of nanogaps and the Fresnel reflection theory, nanofin array is calculated to have ideal properties for an achromatic half-waveplate in the visible band from 560 to 660 nm with the transmittance of around 50%. A Au nanofin array with a height of 830 nm and a period of 400 nm was fabricated through a sidewall-deposition process and overcoating with spin on glass. The polarization microscopy results showed that both transmittance greater than 50% and retardation of 165° at broadband wavelengths ranging from 600 to 800 nm were simultaneously achieved. It was also demonstrated that retardation had little dependence on the incident angle.

Abstract: Polarization topological order of a cylindrical vector beam (CVB) can be defined as the repetition number of 360° polarization state change along the azimuthal axis, with its sign denoting the rotating direction of the polarization In order to detect CVBs with different order, a miniaturized polymer grating is proposed and demonstrated The grating is almost pure phase modulated and polarization independent The CVB modes with different orders or with the same order but opposite sign can easily be separated by adding a quarter wave plate and a polarizer The experimental results are consistent with the theoretical predictions, thus validating our proposed method

Abstract: A novel method for very high resolution measurement of roll angle on a transparent plate is developed theoretically and tested experimentally. The new optical configuration is based on the interferometric readout of phase shift accumulated on the double passage through half wave plate, together with a careful control of polarization state by means of quarter wave plate, and optimizing the tilt of the folding mirror. Sensitivity to roll angle is greatly enhanced and a gain coefficient exceeding 700 is found theoretically, based on Jones' matrix analysis, with a 6-fold increase respect to previous results. In the experimental setup, at the optimum 36° incidence to retroreflector, we measured a gain coefficient of 340. Correspondingly, with an interferometer phase meter resolving 0.01°, a roll-angle resolution 0.1-arc sec is attained.

Abstract: A head mounted display (HMD) includes a display and a pancake lens block. The display with a circular polarizer, comprised of an initial linear polarizer and a first quarter-waveplate with polarizer transmission axis 45° from the waveplate fast axis, emits polarized light. The pancake lens includes a partial reflector, a second quarter-waveplate, and a beam splitting polarizer. The pancake lens receives polarized light from the display. Light propagating through the pancake lens undergoes multiple reflections and transmissions achieved by coordinating changes in polarization of light through these optical elements. To mitigate parasitic light from degrading image quality of the HMD, the fast axis orientation of the first quarter-waveplate is oriented 90° relative to the fast axis orientation of the second quarter-waveplate, and thus the transmission axis of the first polarizer is oriented 90° relative to the transmission axis of the beam splitting polarizer.

Abstract: The invention provides a closed-loop detection method of an atomic gyroscope on the basis of photoelastic modulation. The closed-loop detection method comprises the following steps: a Faraday actuator is placed in front of a 1/4 wave plate and a photoelastic modulator; detection laser passes through a polarizer, a Faraday modulator, an alkali-metal gas chamber, the 1/4 wave plate, the photoelastic modulator and an analyzer in sequence, a fast axis of the 1/4 wave plate and an optical axis of the polarizer are in the same direction, a fast axis of the photoelastic modulator and the optical axis of the polarizer form a 45-degree angle, and the analyzer and the optical axis of the polarizer form a 90-degree angle; a deflection angle of the closed-loop Faraday actuator is controlled by a PID (Proportion Integration Differentiation) controller, the output of a lock-phase amplifier is kept to be zero, and at the same time, the rotating angle to be detected is read out by an output angle of the closed-loop Faraday actuator. The closed-loop detection method provided by the invention has the advantages that the rotating angle to be detected is only related to the rotating angle of the closed-loop Faraday actuator and is not related to the light intensity and the photoelastic modulation amplitude, so that the influence of parameter fluctuation on a detection system is isolated on the principle, a scale factor of the closed-loop photoelastic modulation detection is easily stabilized, and the detection accuracy of the atomic gyroscope is improved.

Abstract: Calibration of the polarimeter system is one of the key elements to determine the overall measurement accuracy. The anisotropic reflection and transmission properties of the mesh beam splitters can easily distort the polarization state of the circularly polarized beams. Using a rotating crystal quartz λ/2-waveplate to replace the plasma can effectively allow us to obtain the ratio of the measured Faraday rotation angle to the known rotation angle of the waveplate. This ratio is used to estimate the calibration factor for each chord to be accurately determined and help to minimize distortions introduced by the wire-mesh beam splitters. With the novel configuration optimization, the distortion of polarization state is effectively eliminated.

Abstract: We present the design of a circular polarization imager for imaging in rainy conditions, which is free from image calibration and correction before obtaining the orthogonal-state contrast image. The system employed a quarter wave plate in front of two Wollaston Prisms (WPs) to capture circularly polarized information and to acquire two orthogonally polarized images simultaneously on the charge coupled device (CCD). Along with the WPs, a reimaging part with multiaperture structure composed of two separate specialized reimaging modules, were implemented to make sure the two orthogonally polarized intensity images are exactly indicating the same scene. Exploiting circularly polarized information provides advantages over a linear polarization imaging system when considering the turbulence of media and illumination. Substantial data have demonstrated the effects of the novel designed polarization imaging system.

Abstract: The quasi-optical modulation of linear polarization at millimeter and sub-millimeter wavelengths can be achieved by using rotating half wave plates (HWPs) in front of polarization sensitive detectors. Large operational bandwidths are required when the same device is meant to work simultaneously across different frequency bands. Previous realizations of half wave plates, ranging from birefringent multi-plate to mesh-based devices, have achieved bandwidths of the order of 100%. Here we present the design and the experimental characterization of a reflective HWP able to work across bandwidths of the order of 150%. The working principle of the novel device is completely different from any previous realization and it is based on the different phase-shift experienced by two orthogonal polarizations respectively reflecting off an electric conductor and off an artificial magnetic conductor.

Abstract: The invention discloses a device for achieving a minitype CPT atomic clock physical system. The device comprises a Bias-Tee, a VCSEL, a first quarter wave plate, an atomic gas chamber, a second quarter wave plate, a polarization beam splitter, a first photoelectric detector and a second photoelectric detector. The invention further discloses a method for achieving the minitype CPT atomic clock physical system. Elliptically-polarized light is adopted for resonance with atom CPT, and difference detection is conducted on the optical rotation effect generated by the resonance. According to the device and method for achieving the minitype CPT atomic clock physical system, background noise generated by optical frequency components which do not interact with atoms in multi-color light output by the VCSEL and conversion noise generated by light interacting with the atoms due to light frequency jitter which is converted into signal amplitude jitter through action with the atoms are eliminated, and the signal to noise ratio of CPT resonance signals is greatly increased; in addition, the device and the method further have the advantages that the influence on the obtained CPT resonance signals by environment magnetic field intensity fluctuation is small, and laser frequency stabilization can be easily achieved through an achieved atomic clock.

Abstract: Surface plasmon polariton (SPP) sources and launchers are highly demanded in various applications of nanophotonics. Here, we propose a general approach that can realize complete control of the complex extinction ratio (including amplitude and phase) of any two linearly independent SPP modes excited by any elementary SPP excitation architecture just by manipulating the incident polarization state. In an optical system, it suffices to simply tune the orientation angles of a linear polarizer and a quarter wave plate, which may greatly simplify the design and application of SPP launchers and diversify their functionalities. As an example to show the broad application prospect of this method, we design and realize a metaline consisting of Δ-shaped plasmonic nanoantennas, which can effectively realize dual functionalities, i.e., the tunable directional SPP excitation at an arbitrarily chosen wavelength and the complete unidirectional SPP excitation over a broad bandwidth. This general approach can also be extended to the control of the complex extinction ratio of any two linearly independent excited modes in many other linear optical systems, such as two modes in a waveguide or two diffraction orders in a grating, over a broad bandwidth.

Abstract: The invention discloses an image-spectrum-polarization-state integrated obtaining apparatus and method. A front-end telescopic system, a lambda/4 wave plate for achromatism, a phase delay, a polarizing film array, a half-wave plate for achromatism, a Wollaston prism, a Savart polariscope, a phase delay, an analyzer LA, an imaging mirror group, and a plane array CCD are arranged from left to right by using a main optical axis as a center along a propagation direction of incident light. Two pairs of dual-channel complementary interferograms are obtained respectively at an upper subarea and a lower subarea of the CCD and the four interferograms are added to obtain target image; pure interference fringes are obtained by subtraction of the interferograms; and the pure interference fringes are added and subtracted to keep single-channel interference fringes and fourier transform is carried out to obtain traditional intensity spectrum and linear polarization spectrum information of a target. Channel filtering of optical path difference dimension is avoided during the spectrum recovery process; and the background noises are inhibited from the hardware.

Abstract: The invention provides a two-degree-of-freedom heterodyne grating interferometer displacement measurement system and method. The system comprises a double-frequency laser device, a grating interferometer, a measuring grating, a receiver and a signal processing unit. The grating interferometer comprises a lateral displacement light splitting prism, a polarization light splitting prism, a 1/4 wave plate, a reflecting mirror and an optical fiber coupler. The method realizes displacement measurement based on grating diffraction, the optical Doppler effect and the optical-beat frequency principle. Laser of the double-frequency laser device is incident to the interferometer and the measuring grating and then optical signals are outputted to the signal processing unit. When the interferometer and the measuring grating perform two-degree-of-freedom linear relative movement, the system can output two linear displacements; the measurement system adopts Littrow incident conditions, a measurement target has large passive movement tolerance and two linear displacements can be measured simultaneously so that precision can reach the nanoscale and higher scale; and the measurement system has advantages of short light path, small size, compact structure, low weight and low requirement for the measuring grating and is suitable for two-degree-of-freedom high-precision long-stroke displacement measurement.

Abstract: We present a novel comprehensive theory for the pump-to-probe interactions caused by the stimulated Raman scattering (SRS) in glass optical fibers. The developed theory applies to both the Raman gain with the undepleted pump assumption, and to the maximum loss induced by the Raman crosstalk (RXT loss). The latter is an effect that is the limiting propagation impairment in passive optical networks (PON). The main novelty of the paper is a rigorous mathematical analysis, describing the interaction of SRS with the polarization evolution due to polarization mode dispersion (PMD). The Raman gain (or the RXT loss) is modeled as a random process for which a comprehensive theory is developed, giving for the first time to our best knowledge, an exact closed-form expression for the mean and variance of the gain (or depletion), and a computationally efficient algorithm to numerically derive the gain probability density function. The developed theory is validated by the comparison with Monte Carlo analyses, based on the waveplate model for the optical fiber. The validation showed excellent agreement, confirming the validity of the developed theory. As an example of application, we used our theoretical results to analyze next-generation PON (NG-PON2) architectures, confirming that, in this scenario, RXT loss may be a limiting propagation effect.

Abstract: Sensors, devices, apparatus, systems and methods for replacing microlens arrays with one or more switchable diffractive waveplate microlens arrays for providing measurements of wavefronts and intensity distribution in light beams with high spatial resolution with a single optical radiation sensor. The device acts like a conventional Shack-Hartmann wavefront sensor when the microlens array elements are in focusing state, and the device performs light beam intensity profile characterization acting as a beam profiler when the optical power of lens array elements is switched off.

Abstract: Diffractive waveplates and equivalent metasurfaces provide a promising path for applications in thin film beam steering, tunable lenses, and polarization filters. However, fixed metasurfaces alone are unable to be tuned electronically. By combining metasurfaces with tunable liquid crystals, we experimentally demonstrate a single layer device capable of electrically switching a diffractive waveplate design at a measured peak diffraction efficiency of 35%, and a minimum switching voltage of 10V. Furthermore, the nano-scale metasurface aligned liquid crystals are largely independent of variations in wavelength and temperature. We also present a computational analysis of the efficiency limits of liquid crystal based diffractive waveplates, and compare this analysis to experimental measurements.

Abstract: In this paper, a chiral metamaterial structure composed of a half-gammadion and H-shape is proposed, which can realize simultaneously dual-band asymmetric transmission (AT) of both linearly and circularly polarized waves in the microwave band. Numerical simulations show that the maximum AT of linearly and circularly polarized waves can reach 0.45 and 0.36 at the resonance frequency, respectively. Specifically, compared with the previous structures, the AT amplitude of the circularly polarized wave is enhanced further. Furthermore, the physical mechanism of polarization conversion of the linearly polarized wave is analyzed by the electric field distributions and the hybridized plasmon coupling modes of the circularly polarized wave are also analyzed based on the currents densities in top and bottom metallic layers in detail. The simulated results are in good agreement with the experimental and theoretical ones for the linearly and circularly polarized waves, respectively.

Abstract: The invention discloses a wave-plate detection device, comprising a light source, a polarizing arm, a sample platform for placing a wave plate to be detected, a polarization detection arm and a detector; the centers of the polarizing arm, the wave plate to be detected and the polarization detection arm are on the same line; the light emitted by the light source is polarized and modulated by the polarizing arm to become modulation polarizing light; the modulation polarization light couples the wave plate information through the wave plate to be detected, and then the modulation and polarization detection are performed on the modulation polarization light through the polarization detection arm; and then the processed modulation polarization light is received by the detector. The invention utilizes the Mueller matrix to establish the relation between the wave plate characteristic parameter and the Mueller matrix, adopts the Mueller matrix ellipsometer to measure the Mueller matrix spectroscopic data of the wave plate to be detected so as to further obtain the characteristic parameter spectral data of the wave plate to be detected. The invention obtains the all characteristic parameter spectral data of any wave plate from one time measurement, and the parameter spectral data comprise phase retardation, a fast axis azimuth, a fast-slow axis transmittance amplitude ratio angle and a depolarization index.

Abstract: The invention discloses a spatial light modulator-based dual-beam optical tweezers system. The system includes a laser, a first telescope system, a half wave plate, a first reflector, a spatial light modulator, a quarter-wave plate, a focusing lens, a second reflector, a second telescope system, an objective lens and a sample stage which are arranged sequentially along an optical path, wherein the half wave plate is used for adjusting the ratio of horizontal polarized light and vertical polarized light in a received beam, the first reflector is used for reflecting the received beam to a corresponding modulation area on the spatial light modulator, and the spatial light modulator is provided with two modulation areas loaded with different phase image information; the beam is subjected to phase modulation once, and then, the phase-modulated beam passes through the quarter-wave plate and the focusing lens, and thereafter is reflected by the second reflector; the reflected beam passes through the focusing lens and the quarter-wave plate again, and arrives at the other modulation region of the spatial light modulator, and thereafter, passes through the second telescope system and the objective lens sequentially, and arrives at the sample stage. With the spatial light modulator-based dual-beam optical tweezers system of the invention adopted, the application range of the optical tweezers can be greatly extended, and experiment accuracy can be improved.

Abstract: We assessed the problem of low mixing efficiency caused by unstable signal polarization because of a moving reflector in a laser communication terminal with a periscopic scanner. A real-time polarization compensation method based on rotating waveplates is presented, which keeps the receiving signal light polarization at 45° linear polarized and improves system mixing efficiency. A geometric model of the laser communication terminal was first established, its polarization transmission characteristics were analyzed by three-dimensional polarization tracks, and a system polarization transmission matrix was calculated. The relationship between scan angle and polarization of the output signal was simulated. The connections between a polarization-compensating λ/4 waveplate and the λ/2 waveplate rotation angle and scan angle were established. These findings will pave the way for real-time polarization control technology for coherent free-space laser communications.

Abstract: The invention provides a lens and method for generating a vortex beam based on a reflecting super-surface, relates to a technology for generating the vortex beam based on a phase discontinuous super-surface, and aims at solving the problem that a traditional method for generating the vortex beam by a spiral phase wave plate is limited by the thickness when the wavelength is relatively large The lens comprises m*n periodically arranged phase change units, wherein each phase change unit comprises a substrate and a reversed Z-shaped metal layer located on the surface of the substrate; each reversed Z-shaped metal layer comprises a metal strip I, a metal strip II and an inclined strip; employing one side of each substrate as an x axis and the side adjacent to the side as a y axis, the included angle between the central line of the corresponding inclined strip and the y axis is theta; the formula is as shown in the specification, wherein l is the orbital angular momentum quantum number; and the formula is as shown in the specification Incident light, entering the lens, of a circularly polarized wave and abnormally reflected light generated when the circularly polarized wave vertically enters the lens are symmetrical about a normal line; a cross-polarized reflection wave is vertical to reflection of the lens; and the abnormal reflection angle is as shown in the specification The lens and the method are suitable for generating the vortex beam

Abstract: Optical properties of a metasurface which can be considered a monolayer of uniaxial metamaterials - parallel-plate and nanorod arrays – are investigated. It is shown that such metasurface acts as an ultimately thin sub-100 nm wave plate. This is achieved via an interplay of epsilon-near-zero and epsilon-near-pole behavior along different axes in the plane of the metasurface allowing for extremely rapid phase difference accumulation in very thin metasurface layers. These effects are shown to not be disrupted by non-locality and can be applied to the design of ultrathin wave plates, Pancharatnam-Berry phase optical elements and plasmon-carrying optical torque wrench devices.

Abstract: The invention belongs to the field of design projection equipment optical systems, particularly relates to a projection optical system improving a light utilization rate and projection brightness, andaims to solve the problem of low light utilization rate and complex system structure which exist in the prior art Polarized light P emitted by a laser source passes through a convergent mirror and is transmitted by a polarized beam splitter prism, polarized light P transmitted by the polarized beam splitter prism passes through a color wheel, an integral square rod and a relay lens group in sequence and is incident to a DMD, emergent light in a projection direction of the DMD is emergent through a project lens, emergent light in a non-projection direction of the DMD passes through a reflex lens group to obtain polarized light S, and polarized light S reflected by the polarized beam splitter prism and the polarized light P transmitted by the polarized beam splitter prism are coaxially incident to the color wheel; and the reflex lens group includes a total reflector A, a relay lens group B, a total reflector B and a 1/2 wave plate; and the emergent light in the non-projection directionof the DMD is sequentially reflected by the total reflector A and refracted by the relay lens group B and 1/2 wave plate to obtain polarized light S