scholarly journals Diffraction efficiency of thin film holographic beam steering devices

2002 ◽  
Author(s):  
Charles M. Titus ◽  
John Pouch ◽  
Hung D. Nguyen ◽  
Felix Miranda ◽  
Philip J. Bos
Keyword(s):  
Thin Film ◽  
Diffraction Efficiency ◽  
Beam Steering

scholarly journals Diffraction Efficiency Enhanced Volume Holographic Gratings via Coupling Ag Thin Film

2019 ◽  
Vol 11 (1) ◽  
pp. 1-5
Author(s):  
Yunping Qiu ◽  
Zhuoya Zhu ◽  
Xiaodie Wang ◽  
Xin Wang ◽  
Yongming Tang ◽  
...  
Keyword(s):  
Thin Film ◽  
Diffraction Efficiency ◽  
Holographic Gratings

Design of multilevel thin-film phase gratings with optimized diffraction efficiency

1991 ◽  
Vol 16 (9) ◽  
pp. 684 ◽  
Author(s):  
Stefano Beretta ◽  
Massimo Cairoli
Keyword(s):  
Thin Film ◽  
Diffraction Efficiency

scholarly journals An Integrated Germanium-Based THz Impulse Radiator with an Optical Waveguide Coupled Photoconductive Switch in Silicon

Micromachines ◽  
2019 ◽  
Vol 10 (6) ◽  
pp. 367 ◽  
Author(s):  
Peiyu Chen ◽  
Mostafa Hosseini ◽  
Aydin Babakhani
Keyword(s):  
Thin Film ◽  
Optical Waveguide ◽  
Low Cost ◽  
Beam Steering ◽  
Optical Excitation ◽  
Silicon On Insulator ◽  
Excitation Wavelength ◽  
Coupling Mechanism ◽  
Photoconductive Switch ◽  
Silicon Lens

This paper presents an integrated germanium (Ge)-based THz impulse radiator with an optical waveguide coupled photoconductive switch in a low-cost silicon-on-insulator (SOI) process. This process provides a Ge thin film, which is used as photoconductive material. To generate short THz impulses, N++ implant is added to the Ge thin film to reduce its photo-carrier lifetime to sub-picosecond for faster transient response. A bow-tie antenna is designed and connected to the photoconductive switch for radiation. To improve radiation efficiency, a silicon lens is attached to the substrate-side of the chip. This design features an optical-waveguide-enabled “horizontal” coupling mechanism between the optical excitation signal and the photoconductive switch. The THz emitter prototype works with 1550 nm femtosecond lasers. The radiated THz impulses achieve a full-width at half maximum (FWHM) of 1.14 ps and a bandwidth of 1.5 THz. The average radiated power is 0.337 μ W. Compared with conventional THz photoconductive antennas (PCAs), this design exhibits several advantages: First, it uses silicon-based technology, which reduces the fabrication cost; second, the excitation wavelength is 1550 nm, at which various low-cost laser sources operate; and third, in this design, the monolithic excitation mechanism between the excitation laser and the photoconductive switch enables on-chip programmable control of excitation signals for THz beam-steering.

A V-Band Beam-Steering Antenna on a Thin-Film Substrate With a Flip-Chip Interconnection

2008 ◽  
Vol 18 (4) ◽  
pp. 287-289 ◽  
Author(s):  
Sanghyo Lee ◽  
Sangsub Song ◽  
Youngmin Kim ◽  
Jangsoo Lee ◽  
Chang-Yul Cheon ◽  
...  
Keyword(s):  
Thin Film ◽  
Flip Chip ◽  
Beam Steering ◽  
V Band ◽  
Film Substrate

Enhanced acousto-optic diffraction efficiency in a symmetric SrTiO_3/BaTiO_3/SrTiO_3 thin-film heterostructure

2000 ◽  
Vol 39 (31) ◽  
pp. 5847 ◽  
Author(s):  
Ranu Nayak ◽  
Vinay Gupta ◽  
Sreenivas Kondepudy
Keyword(s):  
Thin Film ◽  
Diffraction Efficiency

scholarly journals A Switchable Cholesteric Phase Grating with a Low Operating Voltage

Crystals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 100
Author(s):  
Ho-Jin Sohn ◽  
Seung-Won Oh ◽  
Yeongyu Choi ◽  
Seong-Min Ji ◽  
Tae-Hoon Yoon
Keyword(s):  
Diffraction Efficiency ◽  
Beam Steering ◽  
Cholesteric Liquid Crystal ◽  
Grating Period ◽  
Operating Voltage ◽  
Phase Grating ◽  
Cholesteric Phase ◽  
Potential Applications ◽  
Device Applications ◽  
Diffraction Optics

We demonstrate a simple fabrication method of a uniform-lying-helix (ULH) cholesteric liquid crystal (ChLC) cell for phase grating device applications. To utilize a stable ULH state, we set the pitches of ChLCs as half of the cell gap to obtain the fingerprint texture with homeotropic anchoring. With the given grating period, the diffraction efficiency of the ULH cell can be maximized by optimizing the cell gap. We found that the fabricated grating device can provide a large diffraction angle of 10° and a low operating voltage of 3 V with a diffraction efficiency of 30%. We expect potential applications of the device for diffraction optics, optical interconnects, and beam steering devices.

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