A remote gain controlled and polarization angle tunable Doppler backward scattering reflectometer

2021 ◽  
Vol 92 (6) ◽  
pp. 063513
Author(s):  
J. Wen ◽  
Z. B. Shi ◽  
W. L. Zhong ◽  
Z. C. Yang ◽  
Z. J. Yang ◽  
...  
Keyword(s):  
Polarization Angle

Mitigating the Effects of Non-Linear Distortion Using Polarizers in Microwave Photonic Link

2019 ◽  
Vol 0 (0) ◽  
Author(s):  
Sarika Singh ◽  
Sandeep K. Arya ◽  
Shelly Singla
Keyword(s):  
Dynamic Range ◽  
Extinction Ratio ◽  
Polarization Angle ◽  
Third Order ◽  
Microwave Photonic ◽  
Linear Behavior ◽  
Spurious Free Dynamic Range ◽  
Non Linear ◽  
Intermodulation Distortions ◽  
Insertion Losses

AbstractA scheme to suppress nonlinear intermodulation distortion in microwave photonic (MWP) link is proposed by using polarizers to compensate inherent non-linear behavior of dual-electrode Mach-Zehnder modulator (DE-MZM). Insertion losses and extinction ratio have also been considered. Simulation results depict that spurious free dynamic range (SFDR) of proposed link reaches to 130.743 dB.Hz2/3. A suppression of 41 dB in third order intermodulation distortions and an improvement of 15.3 dB is reported when compared with the conventional link. In addition, an electrical spectrum at different polarization angles is extracted and 79^\circ is found to be optimum value of polarization angle.

scholarly journals Predicting the broad-lines polarization emitted by supermassive binary black holes

2019 ◽  
Vol 623 ◽  
pp. A56 ◽  
Author(s):  
D. Savić ◽  
F. Marin ◽  
L. Č. Popović
Keyword(s):  
Black Holes ◽  
Emission Lines ◽  
Polarization Angle ◽  
Broad Line ◽  
Line Profiles ◽  
Binary Black Holes ◽  
True Nature ◽  
Line Shapes ◽  
Highly Sensitive ◽  
Balmer Lines

Context. Some Type-1 active galactic nuclei (AGN) show extremely asymmetric Balmer lines with the broad peak redshifted or blueshifted by thousands of km s−1. These AGN may be good candidates for supermassive binary black holes (SMBBHs). The complex line shapes can be due to the complex kinematics of the two broad line regions (BLRs). Therefore other methods should be applied to confirm the SMBBHs. One of them is spectropolarimetry. Aims. We rely on numerical modeling of the polarimetry of binary black holes systems, since polarimetry is highly sensitive to geometry, in order to find the specific influence of supermassive binary black hole (SMBBH) geometry and dynamics on polarized parameters across the broad line profiles. We apply our method to SMBBHs in which both components are assumed to be AGN with distances at the subparsec scale. Methods. We used a Monte Carlo radiative transfer code that simulates the geometry, dynamics, and emission pattern of a binary system where two black holes are getting increasingly close. Each gravitational well is accompanied by its own BLR and the whole system is surrounded by an accretion flow from the distant torus. We examined the emission line deformation and predicted the associated polarization that could be observed. Results. We modeled scattering-induced broad line polarization for various BLR geometries with complex kinematics. We find that the presence of SMBBHs can produce complex polarization angle profiles φ and strongly affect the polarized and unpolarized line profiles. Depending on the phase of the SMBBH, the resulting double-peaked emission lines either show red or blue peak dominance, or both the peaks can have the same intensity. In some cases, the whole line profile appears as a single Gaussian line, hiding the true nature of the source. Conclusions. Our results suggest that future observation with the high resolution spectropolarimetry of optical broad emission lines could play an important role in detecting subparsec SMBBHs.

Uncalibrated photometric stereo refined by polarization angle

2021 ◽  
Vol 28 (1) ◽  
pp. 119-133
Author(s):  
Daisuke Miyazaki ◽  
Shuhei Hashimoto
Keyword(s):  
Photometric Stereo ◽  
Polarization Angle

scholarly journals Novel Two-Dimensional Layered MoSi2Z4 (Z = P, As): New Promising Optoelectronic Materials

Nanomaterials ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 559
Author(s):  
Hui Yao ◽  
Chao Zhang ◽  
Qiang Wang ◽  
Jianwei Li ◽  
Yunjin Yu ◽  
...  
Keyword(s):  
Optical Absorption ◽  
Incident Light ◽  
Optoelectronic Devices ◽  
Large Family ◽  
Middle Layer ◽  
Optoelectronic Device ◽  
First Principles Calculation ◽  
Polarization Angle ◽  
Two Dimensional ◽  
Conducting Materials

Very recently, two new two-dimensional (2D) layered semi-conducting materials MoSi2N4 and WSi2N4 were successfully synthesized in experiments, and a large family of these two 2D materials, namely MA2Z4, was also predicted theoretically (Science, 369, 670 (2020)). Motivated by this exciting family, in this work, we systematically investigate the mechanical, electronic and optical properties of monolayer and bilayer MoSi2P4 and MoSi2As4 by using the first-principles calculation method. Numerical results indicate that both monolayer and bilayer MoSi2Z4 (Z = P, As) present good structural stability, isotropic mechanical parameters, moderate bandgap, favorable carrier mobilities, remarkable optical absorption, superior photon responsivity and external quantum efficiency. Especially, due to the wave-functions of band edges dominated by d orbital of the middle-layer Mo atoms are screened effectively, the bandgap and optical absorption hardly depend on the number of layers, providing an added convenience in the experimental fabrication of few-layer MoSi2Z4-based electronic and optoelectronic devices. We also build a monolayer MoSi2Z4-based 2D optoelectronic device, and quantitatively evaluate the photocurrent as a function of energy and polarization angle of the incident light. Our investigation verifies the excellent performance of a few-layer MoSi2Z4 and expands their potential application in nanoscale electronic and optoelectronic devices.

scholarly journals Constraints on Lorentz Invariance Violation with Multiwavelength Polarized Astrophysical Sources

Galaxies ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 44
Author(s):  
Qi-Qi Zhou ◽  
Shuang-Xi Yi ◽  
Jun-Jie Wei ◽  
Xue-Feng Wu
Keyword(s):  
Gamma Ray ◽  
Lorentz Invariance ◽  
Polarized Light ◽  
Polarization Plane ◽  
Polarization Angle ◽  
Intrinsic Polarization ◽  
Frequency Dependent ◽  
Invariance Violation ◽  
Linearly Polarized ◽  
Order Of Magnitude

Possible violations of Lorentz invariance (LIV) can produce vacuum birefringence, which results in a frequency-dependent rotation of the polarization plane of linearly polarized light from distant sources. In this paper, we try to search for a frequency-dependent change of the linear polarization angle arising from vacuum birefringence in the spectropolarimetric data of astrophysical sources. We collect five blazars with multiwavelength polarization measurements in different optical bands (UBVRI). Taking into account the observed polarization angle contributions from both the intrinsic polarization angle and the rotation angle induced by LIV, and assuming that the intrinsic polarization angle is an unknown constant, we obtain new constraints on LIV by directly fitting the multiwavelength polarimetric data of the five blazars. Here, we show that the birefringence parameter η quantifying the broken degree of Lorentz invariance is limited to be in the range of −9.63×10−8<η<6.55×10−6 at the 2σ confidence level, which is as good as or represents one order of magnitude improvement over the results previously obtained from ultraviolet/optical polarization observations. Much stronger limits can be obtained by future multiwavelength observations in the gamma-ray energy band.

Effect Analysis of Polarization Aberration in the Non-Line-of-Sight Azimuth Transmission

2021 ◽  
Author(s):  
Zhiyong Yang ◽  
Junchen Song ◽  
Wei Cai ◽  
Danqiu Qiao ◽  
Gaoxiang Lu
Keyword(s):  
Normal Incidence ◽  
Transmission Error ◽  
Transmission System ◽  
Line Of Sight ◽  
Polarization Angle ◽  
Effect Analysis ◽  
Polarized Beam ◽  
Polarization Maintaining ◽  
Selection Of ◽  
Non Line Of Sight

Abstract Focusing on the problem that the polarization aberration caused by the non-normal incidence of the polarized beam affects the accuracy of the azimuth transmission during the fiber coupling process of the non-line-of-sight azimuth transmission system, this paper starts from the principle of non-line-of-sightazimuth transmission. The polarization aberration relation of the lens-fiber combined interface is established based on the Fresnel formulafor the attenuation difference between the horizontal and vertical electric vectors. Further, the azimuth solution model affected by polarization aberration is established. Numerical simulation results show that in non-normal incidence, no polarization aberration will occur when the polarization angle between the incident ray and incident surface is 0° or 90°. Otherwise, the polarization aberration changes toward the incident surface, and the azimuth transmission error will increase with the increase of the polarization aberration. Last, the optimization measures are proposed. This is of great significancefor further improvement of the azimuth transmission system based on polarization-maintaining fibers, the selection of the instrument,and the improvement of the system measurement accuracy.

Theoretical study of micro-structure fabrication by multi-beam laser interference lithography with different polarization combinations

2021 ◽  
pp. 2150459
Author(s):  
Xiangxian Wang ◽  
Tianxu Jia ◽  
Jiankai Zhu ◽  
Yingwen Su ◽  
Liping Zhang ◽  
...  
Keyword(s):  
Manufacturing Industry ◽  
Structural Parameters ◽  
Interference Lithography ◽  
Polarization Angle ◽  
Laser Interference Lithography ◽  
Laser Interference ◽  
Micro Structure ◽  
Periodic Patterns ◽  
Beam Laser ◽  
Micro Structures

In this study, we systematically and comprehensively investigated the influence of polarization angle on the fabrication of micro-structures by multi-beam laser interference lithography. Using theoretical analysis and simulation, we studied the effect of different polarization combinations, i.e. transverse electric (TE) and transverse magnetic (TM) polarization combinations, on the characteristics of the micro-structures fabricated by three-, four-, and six-beam laser interference lithography. We successfully obtained micro-structures with different periodic patterns such as honeycomb dots, quasi-elliptic dots, different square dots, and quasi-triangular dots. The simulation results illustrate that polarization affects the formation of interference patterns, pattern contrasts, and periods. The methods discussed herein are simple, low cost, and allow excellent control over structural parameters, and hence are useful for the micro-structure manufacturing industry.

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