Study on Polarization Distribution of Polarization Encoder in Oblique Incidence

Principle of polarization encoding based on electro-optic effect of LiNbO3 crystal is analyzed, effact on polarization encoding optical field effects is studied when the incident light direction changes. Theoretical calculations show that, with the angle between the direction of incident laser beam and the main axis of LiNbO3 crystal increases, rotation angle of polarization ellipse remain unchanged,but ellipticity changes at any other position except in the center of the encoder,at the top and bottom of encoder,polarization state changes from circularly polarized to elliptically polarized,at other position of the encoder, polarization states are still elliptically polarized light but with different ellipticity angle. Experiment measurement results are in accord with ones of the calculation.

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Formation of half-period surface relief gratings in azobenzene containing polymer films

Applied Physics B ◽

10.1007/s00340-020-07500-w ◽

2020 ◽

Vol 126 (9) ◽

Author(s):

Joachim Jelken ◽

Carsten Henkel ◽

Svetlana Santer

Keyword(s):

Polymer Film ◽

Polymer Films ◽

Surface Relief ◽

Incident Light ◽

Glassy State ◽

Polarized Light ◽

Half Period ◽

Polarization Distribution ◽

Linearly Polarized ◽

Set Up

Abstract We study the peculiar response of photo-sensitive polymer films irradiated with a certain type of interference pattern where one interfering beam is S-polarized, while the second one is P-polarized. The polymer film, although in a glassy state, deforms following the local polarization distribution of the incident light, and a surface relief grating (SRG) appears whose period is half the optical one. All other types of interference patterns result in the matching of both periods. The topographical response is triggered by the alignment of photo-responsive azobenzene containing polymer side chains orthogonal to the local electrical field, resulting in a bulk birefringence grating (BBG). We investigate the process of dual grating formation (SRG and BBG) in a polymer film utilizing a dedicated set-up that combines probe beam diffraction and atomic force microscopy (AFM) measurements, and permits acquiring in situ and in real-time information about changes in local topography and birefringence. We find that the SRG maxima appear at the positions of linearly polarized light (tilted by 45° relative to the grating vector), causing the formation of the half-period topography. This permits to inscribe symmetric and asymmetric topography gratings with sub-wavelength period, while changing only slightly the polarization of one of the interfering beams. We demonstrate an easy generation of sawtooth profiles (blazed gratings) with adjustable shape. With these results, we have taken a significant step in understanding the photo-induced deformation of azo-polymer films.

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Electrical tuning of the polarization state of light using graphene-integrated anisotropic metasurfaces

Philosophical Transactions of The Royal Society A Mathematical Physical and Engineering Sciences ◽

10.1098/rsta.2016.0061 ◽

2017 ◽

Vol 375 (2090) ◽

pp. 20160061 ◽

Cited By ~ 12

Author(s):

Shourya Dutta-Gupta ◽

Nima Dabidian ◽

Iskandar Kholmanov ◽

Mikhail A. Belkin ◽

Gennady Shvets

Keyword(s):

Tilt Angle ◽

Incident Light ◽

Polarization State ◽

Dynamic Control ◽

Single Layer ◽

Single Layer Graphene ◽

Dynamic Polarization ◽

Reflected Light ◽

Electro Optic ◽

The Way

Plasmonic metasurfaces have been employed for moulding the flow of transmitted and reflected light, thereby enabling numerous applications that benefit from their ultra-thin sub-wavelength format. Their appeal is further enhanced by the incorporation of active electro-optic elements, paving the way for dynamic control of light's properties. In this paper, we realize a dynamic polarization state generator using a graphene-integrated anisotropic metasurface (GIAM) that converts the linear polarization of the incident light into an elliptical one. This is accomplished by using an anisotropic metasurface with two principal polarization axes, one of which possesses a Fano-type resonance. A gate-controlled single-layer graphene integrated with the metasurface was employed as an electro-optic element controlling the phase and intensity of light polarized along the resonant axis of the GIAM. When the incident light is polarized at an angle to the resonant axis of the metasurface, the ellipticity of the reflected light can be dynamically controlled by the application of a gate voltage. Thus accomplished dynamic polarization control is experimentally demonstrated and characterized by measuring the Stokes polarization parameters. Large changes of the ellipticity and the tilt angle of the polarization ellipse are observed. Our measurements show that the tilt angle can be changed from positive values through zero to negative values while keeping the ellipticity constant, potentially paving the way to rapid ellipsometry and other characterization techniques requiring fast polarization shifting. This article is part of the themed issue ‘New horizons for nanophotonics’.

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Synthesis of Zero-Birefringence Polymers Based on Positive and Negative Birefringence Polymer

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.428-429.111 ◽

2010 ◽

Vol 428-429 ◽

pp. 111-116

Author(s):

Wen Jun Yang ◽

Guo Zhu Liu ◽

Ji Min Wang ◽

Du Ling Xia

Keyword(s):

High Performance ◽

Incident Light ◽

Polarization State ◽

Polarized Light ◽

Optical Devices ◽

Polymer Chains ◽

Optical Polymers ◽

Orientation Degree ◽

Chain Orientation ◽

Extrusion Processing

Birefringence of a polymer is caused by polymer chain orientation during an injection-molding, extrusion processing or heat drawing. Birefringence of polymers degrades the performance of optical devices that require focusing by lenses or maintaining the polarization state of incident light. Optical polymers which exhibit no birefringence with any orientation of polymer chains are desirable to realize high performance optical devices that handle polarized light. In this study we demonstrate the random copolymerization method for synthesizing the zero-birefringence polymers in which positive and negative birefringence homopolymer are blended. We synthesize a polymer that exhibits no orientational birefringence with any orientation degree in a system that is composed of Methyl methacrylate/Styrene/Benzyl methacrylate.

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Multifunctional Metasurface Lens With Tunable Focus Based on Phase Transition Material

Frontiers in Physics ◽

10.3389/fphy.2021.651898 ◽

2021 ◽

Vol 9 ◽

Author(s):

Yongkang Song ◽

Weici Liu ◽

Xiaolei Wang ◽

Faqiang Wang ◽

Zhongchao Wei ◽

...

Keyword(s):

Phase Transition ◽

Light Field ◽

Focal Point ◽

Incident Light ◽

Polarization State ◽

Polarized Light ◽

Circularly Polarized Light ◽

Circularly Polarized ◽

Multiple Focus ◽

Linearly Polarized

Metasurfaces have powerful light field manipulation capabilities, which have been extensively studied in the past few years and have developed rapidly in various fields. At present, the focus of metasurface research has shifted to the tunable functionality. In this paper, a temperature-controllable multifunctional metasurface lens based on phase transition material is designed. First of all, by controlling the temperature of the desired working area and the polarization of the incident light, switching among multiple focus, single focus, and no focus at any position can be achieved, and the intensity and helicity of the output light can be adjusted. In addition, a polarization-sensitive intensity-tunable metalens based on the P-B phase principle is designed, when the incident light is linearly polarized light, left-handed circularly polarized light, or right-handed circularly polarized light, it has the same focal point but with different light field intensities. Therefore, the focused intensity can be tunable by the polarization state of the incident light.

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A twisted periscope arrangement for transporting elliptically polarized light without change in its polarization state

Review of Scientific Instruments ◽

10.1063/1.3518949 ◽

2010 ◽

Vol 81 (12) ◽

pp. 123102 ◽

Cited By ~ 6

Author(s):

Ashish Arora ◽

Sandip Ghosh

Keyword(s):

Polarization State ◽

Polarized Light ◽

Elliptically Polarized Light ◽

Elliptically Polarized

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Polarization-Sensitive Electro-Optic Sampling of Elliptically-Polarized Terahertz Pulses: Theoretical Description and Experimental Demonstration

Particles ◽

10.3390/particles2010006 ◽

2019 ◽

Vol 2 (1) ◽

pp. 70-89 ◽

Cited By ~ 1

Author(s):

Kenichi Oguchi ◽

Makoto Okano ◽

Shinichi Watanabe

Keyword(s):

Frequency Domain ◽

Time Domain ◽

Probe Pulse ◽

Polarization State ◽

Frequency Component ◽

Phase Mismatch ◽

Pockels Effect ◽

Electro Optic ◽

Domain Description ◽

Elliptically Polarized

We review our recent works on polarization-sensitive electro-optic (PS-EO) sampling, which is a method that allows us to measure elliptically-polarized terahertz time-domain waveforms without using wire-grid polarizers. Because of the phase mismatch between the employed probe pulse and the elliptically-polarized terahertz pulse that is to be analyzed, the probe pulse senses different terahertz electric-field (E-field) vectors during the propagation inside the EO crystal. To interpret the complex condition inside the EO crystal, we expressed the expected EO signal by “frequency-domain description” instead of relying on the conventional Pockels effect description. Using this approach, we derived two important conclusions: (i) the polarization state of each frequency component can be accurately measured, irrespective of the choice of the EO crystal because the relative amplitude and phase of the E-field of two mutually orthogonal directions are not affected by the phase mismatch; and, (ii) the time-domain waveform of the elliptically-polarized E-field vector can be retrieved by considering the phase mismatch, absorption, and the effect of the probe pulse width. We experimentally confirm the above two conclusions by using different EO crystals that are used for detection. This clarifies the validity of our theoretical analysis based on the frequency-domain description and the usefulness of PS-EO sampling.

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Efficient Achromatic Broadband Focusing and Polarization Manipulation of a Novel Designed Multifunctional Metasurface Zone Plate

Nanomaterials ◽

10.3390/nano11123436 ◽

2021 ◽

Vol 11 (12) ◽

pp. 3436

Author(s):

Shaobo Ge ◽

Weiguo Liu ◽

Xueping Sun ◽

Jin Zhang ◽

Pengfei Yang ◽

...

Keyword(s):

Degrees Of Freedom ◽

Incident Light ◽

Polarization State ◽

Resonance Effect ◽

Optical Design ◽

Polarized Light ◽

Simulation Method ◽

Zone Plate ◽

Circularly Polarized Light ◽

Circularly Polarized

In this paper, comprehensively utilizing the diffraction theory and electromagnetic resonance effect is creatively employed to design a multifunctional metasurface zone plate (MMZP) and achieve the control of polarization states, while maintaining a broadband achromatic converging property in a near-IR region. The MMZP consists of several rings with fixed width and varying heights; each ring has a number of nanofins (usually called meta-atoms). The numerical simulation method is used to analyze the intensity distribution and polarization state of the emergent light, and the results show that the designed MMZP can realize the polarization manipulation while keeping the broadband in focus. For a specific design wavelength (0.7μm), the incident light can be converted from left circularly polarized light to right circularly polarized light after passing through the MMZP, and the focusing efficiency reaches above 35%, which is more than twice as much as reported in the literature. Moreover, the achromatic broadband focusing property of the MMZP is independent with the polarization state of the incident light. This approach broadens degrees of freedom in micro-nano optical design, and is expected to find applications in multifunctional focusing devices and polarization imaging.

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Full-parallax 3D display using time-multiplexing projection technology

Electronic Imaging ◽

10.2352/issn.2470-1173.2020.2.sda-100 ◽

2020 ◽

Vol 2020 (2) ◽

pp. 100-1-100-6

Author(s):

Takuya Omura ◽

Hayato Watanabe ◽

Naoto Okaichi ◽

Hisayuki Sasaki ◽

Masahiro Kawakita

Keyword(s):

Incident Light ◽

Polarization State ◽

3D Image ◽

3D Display ◽

Time Division Multiplexing ◽

3D Images ◽

Polarization Gratings ◽

Light Rays ◽

Time Division

We enhanced the resolution characteristics of a threedimensional (3D) image using time-division multiplexing methods in a full-parallax multi-view 3D display. A time-division light-ray shifting (TDLS) method is proposed that uses two polarization gratings (PGs). As PG changes the diffraction direction of light rays according to the polarization state of the incident light, this method can shift light rays approximately 7 mm in a diagonal direction by switching the polarization state of incident light and adjusting the distance between the PGs. We verified the effect on the characteristics of 3D images based on the extent of the shift. As a result, the resolution of a 3D image with depth is improved by shifting half a pitch of a multi-view image using the TDLS method, and the resolution of the image displayed near the screen is improved by shifting half a pixel of each viewpoint image with a wobbling method. These methods can easily enhance 3D characteristics with a small number of projectors.

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