scholarly journals Dichroic Circular Polarizers Based on Plasmonics for Polarization Imaging Applications

Nanomaterials ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 2145
Author(s):  
Junyan Zheng ◽  
Xin He ◽  
Paul Beckett ◽  
Xinjie Sun ◽  
Zixin Cai ◽  
...  
Keyword(s):  
Incident Light ◽  
Polarization State ◽  
Optical Loss ◽  
Optical Filters ◽  
Transmission Efficiency ◽  
Visible Range ◽  
Angle Of Incidence ◽  
Polarization Imaging ◽  
Visible Wavelengths ◽  
Maximum Transmission

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

scholarly journals A Thermal Tuning Meta-Duplex-Lens (MDL): Design and Characterization

Nanomaterials ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 1135 ◽  
Author(s):  
Ning Xu ◽  
Yaoyao Liang ◽  
Yuan Hao ◽  
Min Mao ◽  
Jianping Guo ◽  
...  
Keyword(s):  
Phase Change ◽  
Phase Change Material ◽  
Electromagnetic Waves ◽  
Incident Light ◽  
Polarization State ◽  
Transmission Efficiency ◽  
Metallic State ◽  
Phase Gradient ◽  
Storage Devices ◽  
Change Material

Multifunctional metasurfaces play an important role in the development of integrated optical paths. However, some of the realizations of current multifunctional metasurface devices depend on polarization selectivity, and others change the polarization state of the outgoing light. Here, based on vanadium dioxide (VO2) phase change material, a strategy to design a meta-duplex-lens (MDL) is proposed and numerical simulation calculations demonstrate that at low temperature (about 300 K), VO2 behaves as a dielectric so that the MDL can act as a transmission lens (transmission efficiency of 87.6%). Conversely, when VO2 enters the metallic state (about 355 K), the MDL has the ability to reflect and polymerize electromagnetic waves and works as a reflection lens (reflection efficiency of 85.1%). The dielectric waveguide and gap-surface plasmon (GSP) theories are used in transmission and reflection directions, respectively. In order to satisfy the coverage of the phase gradient in the range of 2π in both cases, we set the antenna as a nanopillar with a high aspect ratio. It is notable that, via symmetrical antennas acting in concert with VO2 phase change material, the polarization states of both the incident light and the outgoing light are not changed. This reversible tuning will play a significant role in the fields of imaging, optical storage devices, communication, sensors, etc.

scholarly journals Polarization-Independent Metasurface Lens Based on Binary Phase Fresnel Zone Plate

Nanomaterials ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 1467
Author(s):  
Xing Li ◽  
Jing Tang ◽  
Jonathan Baine
Keyword(s):  
Fresnel Zone ◽  
Incident Light ◽  
Polarization State ◽  
Zone Plate ◽  
Visible Range ◽  
Fresnel Zone Plate ◽  
Binary Phase ◽  
Nanophotonic Devices ◽  
Potential Applications ◽  
Polarization Independent

Based on the binary phase Fresnel zone plate (FZP), a polarization-independent metasurface lens that is able to focus incident light with any polarization state, including circular, linear, and elliptical polarizations, has been proposed and investigated. We demonstrate that the metasurface lens consisting of metal subwavelength slits can operate in a wide bandwidth in the visible range, and has a higher focusing efficiency than that of an amplitude FZP lens without phase modulation. A multi-focus FZP metasurface lens has also been designed and investigated. The proposed lens can provide potential applications in integrated nanophotonic devices without polarization limitations.

scholarly journals Electrostatically Tuned Optical Filters Based on Hybrid Plasmonic-Dielectric Thin Films for Hyperspectral Imaging

Micromachines ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 767
Author(s):  
Ahmed Abdelghfar ◽  
Mohamed A. Mousa ◽  
Bassant M. Fouad ◽  
Ahmed H. Saad ◽  
Noha Anous ◽  
...  
Keyword(s):  
Hyperspectral Imaging ◽  
Optical Filter ◽  
Optical Filters ◽  
Medical Diagnostics ◽  
Visible Range ◽  
Crop Monitoring ◽  
Tunable Optical Filter ◽  
Wide Range ◽  
Fabry Perot ◽  
Maximum Transmission

Hyperspectral imaging has a wide range of uses, from medical diagnostics to crop monitoring; however, conventional hyperspectral imaging systems are relatively slow, bulky, and rather costly. In this paper, we present an inexpensive, compact tunable optical filter for hyperspectral applications. The filter is based on a Fabry-Pérot interferometer utilizing hybrid metallic-dielectric mirrors and actuated using a MEMS electrostatic actuator. The optical filter is designed using the transfer matrix method; then, the results were verified by an electromagnetic wave simulator. The actuator is based on a ring-shaped parallel plate capacitor and is designed using COMSOL Multiphysics. An actuation displacement of 170 nm was used, which is the required distance to tune the filter over the whole visible range (400–700 nm). There are two designs proposed for the optical filter: the first was optimized to provide maximum transmission and the other is optimized to have minimum full-width-half-maximum (FWHM) value. The first design has a maximum transmission percentage of 94.45% and a minimum transmission of 86.34%; while the minimum FWHM design had an average FWHM value of 7.267 nm. The results showed improvements over the current commercial filters both in transmission and in bandwidth.

scholarly journals Design of Polarization-Independent and Wide-Angle Broadband Absorbers for Highly Efficient Reflective Structural Color Filters

Materials ◽  
2019 ◽  
Vol 12 (7) ◽  
pp. 1050 ◽  
Author(s):  
Kyu-Tae Lee ◽  
Daeshik Kang ◽  
Hui Park ◽  
Dong Park ◽  
Seungyong Han
Keyword(s):  
High Efficiency ◽  
Incident Light ◽  
Polarization State ◽  
Visible Range ◽  
Broadband Absorption ◽  
Research Areas ◽  
Simple Strategy ◽  
Planar Structures ◽  
Color Filters ◽  
Polarization Independent

We propose a design of angle-insensitive and polarization-independent reflective color filters with high efficiency (>80%) based on broad resonance in a Fabry–Pérot cavity where asymmetric metal-dielectric-metal planar structures are employed. Broadband absorption properties allow the resonance in the visible range to remain nearly constant over a broad range of incident angles of up to 40° for both s- and p-polarizations. Effects of the angles of incidence and polarization state of incident light on the purity of the resulting colors are examined on the CIE 1931 chromaticity diagram. In addition, higher-order resonances of the proposed color filters and their electric field distributions are investigated for improved color purity. Lastly, the spectral properties of the proposed structures with different metallic layers are studied. The simple strategy described in this work could be adopted in a variety of research areas, such as color decoration devices, microscopy, and colorimetric sensors.

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

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.

Bilayer PMMA antireflective coatings via microphase separation and MAPLE

2020 ◽  
Vol 41 (2) ◽  
pp. 164-173
Author(s):  
Yunlong Guo ◽  
Shuzhen Ren
Keyword(s):  
Microphase Separation ◽  
Incident Light ◽  
Visible Range ◽  
Laser Evaporation ◽  
Antireflective Coatings ◽  
Porous Network ◽  
Cross Sectional ◽  
Polymer Thin Film ◽  
Deposition Parameters ◽  
Surface Morphologies

Abstract A poly(methyl methacrylate) (PMMA) bilayer antireflective coating (ARC) is designed based on polymeric microphase separation and matrix-assisted pulsed laser evaporation (MAPLE). The spin-coated layer shows subwavelength porous network structures, after phase separation via annealing and removal of the polystyrene (PS) phase, while the MAPLE deposited surface layer exhibits a biomimic moth-eye structure on glass to trap the incident light. The elaborate spin coated structure can be controlled flexibly by changing the ratio of mixture, annealing time and temperature, and the moth-eye structure can also be tuned by deposition parameters. The transmittance of the ARC presents a maximum of 95.64% and an average of 94.81% in visible range. The moth-eye structure on glass substrate formed by nanoglobules makes positive contributions to the improvement of transmittance according to UV–Vis result and simulation. The wetting motion of PMMA globules is observed as well by the comparison of AFM surface morphologies and cross-sectional profiles of globules on glass and polymer thin film. This work is a novel attempt to fabricate bilayer ARC with two different structures by a single polymeric material and will provide new route for fabrication of multilayer ARCs.

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

2017 ◽  
Vol 375 (2090) ◽  
pp. 20160061 ◽  
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’.

scholarly journals DIGITAL IMAGE ANALYSIS OF THE VISIBLE REGION THROUGH SIMULATION OF ROCK ART PAINTINGS

2016 ◽  
Author(s):  
Berta Carrión-Ruiz ◽  
Silvia Blanco-Pons ◽  
Jose Luis Lerma
Keyword(s):  
Rock Art ◽  
Visible Region ◽  
Visible Spectrum ◽  
Principal Component ◽  
Optical Filters ◽  
Visible Range ◽  
Redundant Data ◽  
The Difference ◽  
Entire Visible Spectrum ◽  
New Research

Non-destructive rock art recording techniques are getting special attention in the last years, opening new research lines in order to improve the level of documentation and understanding of our rich legacy. This paper applies the principal component analysis (PCA) technique in images that include wavelengths between 400-700 nm (visible  range). Our approach is focused on determining the difference provided by the image processing of the visible region through four spectral images versus an image that encompasses the entire visible spectrum. The images were taken by means of optical filters that take specific wavelengths and exclude parts of the spectrum. Simulation of rock art is prepared in laboratory. For this purpose, three different pigments were made simulating the material composition of rock art paintings. The advantages of studying the visible spectrum in separate images are analysed. In addition, PCA is applied to each of the images to reduce redundant data. Finally, PCA is applied to the image that contains the entire visible spectrum and is compared with previous results. Through the results of the four visible spectral images one can begin to draw conclusions about constituent painting materials without using decorrelation techniques.

scholarly journals Unidirectional propagation of the Bloch surface wave excited by the spinning magnetic dipole in two-dimensional photonic crystal slab

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Li-Ming Zhao ◽  
Yun-Song Zhou
Keyword(s):  
Photonic Crystal ◽  
Surface Wave ◽  
Magnetic Dipole ◽  
Incident Light ◽  
Polarization State ◽  
Oscillation Period ◽  
Unit Cell ◽  
Average Spin ◽  
Component Wave ◽  
Bloch Surface Wave

AbstractThe photonic spin Hall effect (PSHE) can be realized in a photonic crystal (PC) slab, that is, the unidirectional Bloch surface wave can propagate along the surface of the PC slab under the excitation of elliptical polarized magnetic dipole. It is further proved that PSHE is caused by the interference of the component surface waves excited by the different components of the incident light, which is the so called component wave interference (CWI) theory. In addition, we also find that the spin of the surface wave oscillates periodically in space, and the oscillation period is a unit cell. In a unit cell, the average spin keeps the spin orbit locked. The results show that the spin separation can also be modulated by the position and the polarization state of the magnetic dipole.

scholarly journals Numerical Investigation of a Designed-Inlet Optofluidic Beam Splitter for Split-Angle and Transmission Improvement

Micromachines ◽  
2021 ◽  
Vol 12 (10) ◽  
pp. 1200
Author(s):  
Ting-Yuan Lin ◽  
Chih-Yang Wu
Keyword(s):  
Beam Splitter ◽  
Incident Light ◽  
Transmission Efficiency ◽  
Main Channel ◽  
Calcium Chloride Solution ◽  
Deionized Water ◽  
Flow Rate Ratio ◽  
Horizontal Line ◽  
Simulation And Experiment ◽  
Side Walls

The beam splitter is one of the important elements in optical waveguide circuits. To improve the performance of an optofluidic beam splitter, a microchannel including a two-stage main channel with divergent side walls and two pairs of inlet channels is proposed. Besides, the height of the inlets injected with cladding fluid is set to be less than the height of other parts of the microchannel. When we inject calcium chloride solution (cladding fluid) and deionized water (core fluid) into the inlet channels, the gradient refractive index (GRIN) developed in fluids flowing through the microchannel split the incident light beam into two beams with a larger split angle. Moreover, the designed inlets yield a GRIN distribution which increases the light collected around the middle horizontal line on the objective plane, and so enhances the transmission efficiency of the device. To demonstrate the performance of the proposed beam splitter, we use polydimethylsiloxane to fabricate the microchannel. The results obtained by simulation and experiment are compared to show the effectiveness of the device and the validity of numerical simulation. The influence of the microchannel geometry and the flow rate ratio on the performance of the proposed beam splitter is investigated.

Sign in / Sign up

Export Citation Format

Share Document