See-Through Aerial Concave Display by Use of Fresnel Lens and AIRR with Polarization Modulation

2019 ◽  
pp. 150
Author(s):  
Shuto Hatsumi ◽  
Kazuki Shimose ◽  
Masaki Yasugi ◽  
Hirotsugu Yamamoto
Keyword(s):  
Fresnel Lens ◽  
Polarization Modulation

Far-Infrared Fresnel Lens for Thermal Imaging

2013 ◽  
Vol 133 (7) ◽  
pp. 274-279
Author(s):  
Tomoyuki Takahata ◽  
Kiyoshi Matsumoto ◽  
Isao Shimoyama
Keyword(s):  
Thermal Imaging ◽  
Far Infrared ◽  
Fresnel Lens

scholarly journals Neuro-Inspired Computing with Spin-VCSELs

2021 ◽  
Vol 11 (9) ◽  
pp. 4232
Author(s):  
Krishan Harkhoe ◽  
Guy Verschaffelt ◽  
Guy Van der Sande
Keyword(s):  
Processing Speed ◽  
Delay Time ◽  
High Speed ◽  
State Of The Art ◽  
Polarization Modulation ◽  
Time Interval ◽  
Computing Technique ◽  
High Modulation ◽  
Short Time ◽  
Modulation Speed

Delay-based reservoir computing (RC), a neuromorphic computing technique, has gathered lots of interest, as it promises compact and high-speed RC implementations. To further boost the computing speeds, we introduce and study an RC setup based on spin-VCSELs, thereby exploiting the high polarization modulation speed inherent to these lasers. Based on numerical simulations, we benchmarked this setup against state-of-the-art delay-based RC systems and its parameter space was analyzed for optimal performance. The high modulation speed enabled us to have more virtual nodes in a shorter time interval. However, we found that at these short time scales, the delay time and feedback rate heavily influence the nonlinear dynamics. Therefore, and contrary to other laser-based RC systems, the delay time has to be optimized in order to obtain good RC performances. We achieved state-of-the-art performances on a benchmark timeseries prediction task. This spin-VCSEL-based RC system shows a ten-fold improvement in processing speed, which can further be enhanced in a straightforward way by increasing the birefringence of the VCSEL chip.

scholarly journals Electrical Tuning of Fresnel Lens in Reflection

ACS Photonics ◽  
2021 ◽  
Author(s):  
Christopher Damgaard-Carstensen ◽  
Martin Thomaschewski ◽  
Fei Ding ◽  
Sergey I. Bozhevolnyi
Keyword(s):  
Fresnel Lens

scholarly journals Spin Laser Local Oscillators for Homodyne Detection in Coherent Optical Communications

Micromachines ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 573
Author(s):  
Nobuhide Yokota ◽  
Hiroshi Yasaka
Keyword(s):  
Spin Polarization ◽  
Optical Communications ◽  
Injection Locking ◽  
Optical Data ◽  
Cavity Surface ◽  
Orthogonal Polarization ◽  
Linear Birefringence ◽  
Polarization Modulation ◽  
Homodyne Detection ◽  
Local Oscillators

We numerically investigate spin-controlled vertical-cavity surface-emitting lasers (spin-VCSELs) for local oscillators, which are based on an injection locking technique used in coherent optical communications. Under the spin polarization modulation of an injection-locked spin-VCSEL, frequency-shifted and phase-correlated optical sidebands are generated with an orthogonal polarization against the injection light, and one of the sidebands is resonantly enhanced due to the linear birefringence in the spin-VCSEL. We determine that the peak strength and peak frequency in the spin polarization modulation sensitivity of the injection-locked spin-VCSEL depend on detuning frequency and injection ratio conditions. As a proof of concept, 25-Gbaud and 16-ary quadrature amplitude modulation optical data signals and a pilot tone are generated, and the pilot tone is used for the injection locking of a spin-VCSEL. An orthogonally-polarized modulation sideband generated from the injection-locked spin-VCSEL is used as a frequency-shifted local oscillator (LO). We verify that the frequency-shifted LO can be used for the homodyne detection of optical data signals with no degradation. Our findings suggest a novel application of spin-VCSELs for coherent optical communications.

Design and Evaluation of the Fresnel-Lens Based Solar Concentrator System Through a Statistical-Algorithmic Approach

2018 ◽  
Author(s):  
Hassan Qandil ◽  
Weihuan Zhao
Keyword(s):  
High Temperature ◽  
High Efficiency ◽  
Incident Light ◽  
Thermal Analyses ◽  
Solar Spectrum ◽  
Chromatic Aberration ◽  
Fresnel Lens ◽  
Optimum Number ◽  
Solar Concentrator ◽  
Receiver System

A novel non-imaging Fresnel-lens-based solar concentrator-receiver system has been investigated to achieve high-efficiency photon and heat outputs with minimized effect of chromatic aberrations. Two types of non-imaging Fresnel lenses, a spot-flat lens and a dome-shaped lens, are designed through a statistical algorithm incorporated in MATLAB. The algorithm optimizes the lens design via a statistical ray-tracing methodology of the incident light, considering the chromatic aberration of solar spectrum, the lens-receiver spacing and aperture sizes, and the optimum number of prism grooves. An equal-groove-width of the Poly-methyl-methacrylate (PMMA) prisms is adopted in the model. The main target is to maximize ray intensity on the receiver’s aperture, and therefore, achieve the highest possible heat flux and output concentration temperature. The algorithm outputs prism and system geometries of the Fresnel-lens concentrator. The lenses coupled with solar receivers are simulated by COMSOL Multiphysics. It combines both optical and thermal analyses for the lens and receiver to study the optimum lens structure for high solar flux output. The optimized solar concentrator-receiver system can be applied to various devices which require high temperature inputs, such as concentrated photovoltaics (CPV), high-temperature stirling engine, etc.

scholarly journals Spin-VCSELs with Local Optical Anisotropies: Toward Terahertz Polarization Modulation

2021 ◽  
Vol 15 (1) ◽  
Author(s):  
M. Drong ◽  
T. Fördös ◽  
H.Y. Jaffrès ◽  
J. Peřina ◽  
K. Postava ◽  
...  
Keyword(s):  
Polarization Modulation

scholarly journals Optical Performance of Single Point-Focus Fresnel Lens Concentrator System for Multiple Multi-Junction Solar Cells—A Numerical Study

Energies ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4301
Author(s):  
Yassir A. Alamri ◽  
Saad Mahmoud ◽  
Raya Al-Dadah ◽  
Shivangi Sharma ◽  
J. N. Roy ◽  
...  
Keyword(s):  
Solar Cells ◽  
Numerical Study ◽  
Single Point ◽  
Optical Element ◽  
Fresnel Lens ◽  
Electrical Performance ◽  
High Concentration ◽  
Three Dimensional Model ◽  
Optical Efficiency ◽  
Concave Lens

This paper investigates the potential of a new integrated solar concentrated photovoltaic (CPV) system that uses a solo point focus Fresnel lens for multiple multi-junction solar cells (MJSCs). The proposed system comprises of an FL concentrator as the primary optical element, a multi-leg homogeniser as the secondary optical element (SOE), a plano-concave lens, and four MJSCs. A three-dimensional model of this system was developed using the ray tracing method to predict the influence of aperture width, height, and position with respect to MJSCs of different reflective and refractive SOE on the overall optical efficiency of the system and the irradiance uniformity achieved on the MJSCs’ surfaces. The results show that the refractive homogeniser using N-BK7 glass can achieve higher optical efficiency (79%) compared to the reflective homogeniser (57.5%). In addition, the peak to average ratio of illumination at MJSCs for the reflective homogeniser ranges from 1.07 to 1.14, while for the refractive homogeniser, it ranges from 1.06 to 1.34, causing minimum effects on the electrical performance of the MJSCs. The novelty of this paper is the development of a high concentration CPV system that integrates multiple MJSCs with a uniform distribution of rays, unlike the conventional CPV systems that utilise a single concentrator onto a single MJSC. The optical efficiency of the CPV system was also examined using both the types of homogeniser (reflective and refractive).

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