scholarly journals Microwave Photonic Devices Based on Liquid Crystal on Silicon Technology

2019 ◽  
Vol 9 (2) ◽  
pp. 260 ◽  
Author(s):  
Ruiqi Zheng ◽  
Erwin Chan ◽  
Xudong Wang ◽  
Xinhuan Feng ◽  
Bai-Ou Guan

This paper reviews the recent developments in microwave photonic devices based on liquid crystal on silicon (LCOS) technology. The operation principle, functions and important specifications of an LCOS based optical processor are described. Three microwave photonic devices, which are microwave photonic notch filters, phase shifters and couplers, reported in the past five years are focused on in this paper. In addition, a new multi-function signal processing structure based on amplitude and phase control functions in conjunction with a power splitting function in a commercial LCOS based optical processor is presented. It has the ability to realize multiple time -shifting operations and multiple frequency-independent phase shifting operations at the same time and control multiple RF signal amplitudes, in a single unit. The results for the new multi-function microwave photonic signal processor demonstrate multiple tunable true time delay and phase shifting operations with less than 3 dB amplitude variation over a very wide frequency range of 10 to 40 GHz.

Author(s):  
Roberto Fernandez ◽  
Sergi Gallego ◽  
Francisco J. Martinez ◽  
Andres Marquez ◽  
Inmaculada Pascual ◽  
...  

Crystals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 605
Author(s):  
Ayushi Rastogi ◽  
Fanindra Pandey ◽  
Rajiv Manohar ◽  
Shri Singh

We report the effect of the doping of Cd1−xZnxS/ZnS core/shell quantum dots (CSQDs) in nematic liquid crystal p-methoxybenzylidenep-decylaniline (MBDA) at 0.05 wt/wt%, 0.1 wt/wt%, 0.15 wt/wt%, 0.2 wt/wt%, 0.25 wt/wt%, and 0.3 wt/wt% concentrations of CSQDs in MBDA. Dielectric parameters with and without bias with respect to frequency have been investigated. The change in electro-optical parameters with temperature has also been demonstrated. The increase in the mean dielectric permittivity was found due to the large dipole moment of CSQDs, which impose stronger interactions with the liquid crystal molecules. The dielectric anisotropy changes sign on doping CSQDs in MBDA liquid crystal. It was concluded that the CSQD doping noticeably increased the dielectric permittivity of nematic MBDA in the presence of an electric field. The doping of CSQDs in nematic MBDA liquid crystal reduced the ion screening effect effectively. This phenomenon is attributed to the competition between the generated ionic impurities during the assembling process and the ion trapping effect of the CSQDs. The rotational viscosity of nematic liquid crystal decreased with increasing concentration of the CSQDs, with a faster response time observed for the 0.05 wt/wt% concentration. The birefringence of the doped system increased with the inclusion of CSQDs in MBDA. These results find application in the field of display devices, phase shifters, LC – gratings, TIR waveguide, industries, and projectors.


2011 ◽  
Vol 20 (04) ◽  
pp. 477-484 ◽  
Author(s):  
HUNG-CHUN LIN ◽  
MING-SYUAN CHEN ◽  
YI-HSIN LIN

An electrically tunable liquid-crystal-on-silicon (LCOS)-based pico projection system based on a liquid crystal lens adopting a liquid crystal and polymer composite film (LCPCF) is demonstrated. The LC lens consists of two built-in sub-lenses: one is an electrically tunable focusing lens controlled by a LC layer and the other is a fixed focused LCPCF lens. The electrically tunable focusing range of the pico projection system is 200 cm to ~7 cm when the voltage is from 0 to 35 Vrms. The image performance is also demonstrated. The related optical analysis is discussed. This study opens a new window for electrically tunable focusing pico projection system.


2006 ◽  
Vol 24 (4) ◽  
pp. 1546-1551 ◽  
Author(s):  
Karen Hendrix ◽  
Kim Tan ◽  
Markus Duelli ◽  
David Shemo ◽  
Markus Tilsch

Sensors ◽  
2021 ◽  
Vol 21 (3) ◽  
pp. 967
Author(s):  
Zhen Zeng ◽  
Zexiao Li ◽  
Fengzhou Fang ◽  
Xiaodong Zhang

Phase compensation is a critical step for the optical measuring system using spatial light modulator (SLM). The wavefront distortion from SLM is mainly caused by the phase modulation non-linearity and non-uniformity of SLM’s physical structure and environmental conditions. A phase modulation characteristic calibration and compensation method for liquid crystal on silicon spatial light modulator (LCoS-SLM) with a Twyman-Green interferometer is illustrated in this study. A method using two sequences of phase maps is proposed to calibrate the non-uniformity character over the whole aperture of LCoS-SLM at pixel level. A phase compensation matrix is calculated to correct the actual phase modulation of the LCoS-SLM and ensure that the designed wavefront could be achieved. Compared with previously known compensation methods, the proposed method could obtain the phase modulation characteristic curve of each pixel on the LCoS-SLM, rather than a mono look-up table (LUT) curve or multi-LUT curves corresponding to an array of blocks over the whole aperture of the LCoS-SLM. The experiment results show that the phase compensation precision could reach a peak-valley value of 0.061λ in wavefront and this method can be applied in generating freeform wave front for precise optical performance.


2002 ◽  
Vol 41 (Part 1, No. 7A) ◽  
pp. 4577-4585 ◽  
Author(s):  
Kuan-Hsu Fan Chiang ◽  
Shin-Tson Wu ◽  
Shu-Hsia Chen

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