Programmable polarization-independent spectral phase compensation and pulse shaping by use of a single-layer liquid-crystal modulator

2006 ◽  
Vol 45 (20) ◽  
pp. 4858 ◽  
Author(s):  
C. G. Slater ◽  
D. E. Leaird ◽  
A. M. Weiner
Author(s):  
Veronika S. Bezruchenko ◽  
Alexander A. Muravsky ◽  
Anatoli A. Murauski ◽  
Alexander I. Stankevich ◽  
Uladzimir V. Mahilny

Author(s):  
Yanning Yuan ◽  
Yuchen Zhao ◽  
Xiaoli Xi

Abstract A single-layer ultra-wideband (UWB) stop-band frequency selective surface (FSS) has several advantages in wireless systems, including a simple design, low debugging complexity, and an appropriate thickness. This study proposes a miniaturized UWB stop-band FSS design. The proposed FSS structure consists of a square-loop and metalized vias that are arranged on a single layer substrate; it has an excellent angle and polarization-independent characteristics. At an incident angle of 60°, the polarization response frequencies of the transverse electric and magnetic modes only shifted by 0.003 f0 and 0.007 f0, respectively. The equivalent circuit models of the square-loop and metallized vias structure are analysed and the accuracy of the calculation is evaluated by comparing the electromagnetic simulation. The 20 × 20 array constitutes an FSS reflector with a unit size of 4.2 mm × 4.2 mm (less than one-twentieth of the wavelength of 3 GHz), which realizes an UWB quasi-constant gain enhancement (in-band flatness is <0.5 dB). Finally, the simulation results were verified through sample processing and measurement; consistent results were obtained. The FSS miniaturization design method proposed in this study could be applied to the design of passband FSS (complementary structure), antennas and filters, among other applications.


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.


2021 ◽  
Author(s):  
Brandon Vreeland ◽  
Comrun Yousefzadeh ◽  
Andre van Rynbach ◽  
Douglas Bryant ◽  
Philip J. Bos

2008 ◽  
Vol 39 (1) ◽  
pp. 236 ◽  
Author(s):  
Ravi K. Komanduri ◽  
Chulwoo Oh ◽  
Michael J. Escuti ◽  
D. Jason Kekas

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