scholarly journals A Diamagnetic-Loop-Based Beam Radius Monitor (BRM)

2021 ◽  
Author(s):  
Horace Smith ◽  
William Broste ◽  
Carl Ekdahl
Keyword(s):  
Beam Radius ◽  
Diamagnetic Loop

scholarly journals A Broadband High-Diffraction-Efficiency Electro-Optic Bragg Deflector Based on Monolithic Dual-Grating Periodically-Poled Lithium Niobate

Photonics ◽  
2021 ◽  
Vol 8 (7) ◽  
pp. 242
Author(s):  
An-Chung Chiang ◽  
Yuan-Yao Lin ◽  
Shou-Tai Lin ◽  
Yen-Yin Lin
Keyword(s):  
Lithium Niobate ◽  
Wave Theory ◽  
Beam Radius ◽  
Acceptance Angle ◽  
Periodically Poled ◽  
Periodically Poled Lithium Niobate ◽  
Electro Optic ◽  
Recent Developments ◽  
Strong Focusing ◽  
Grating Design

Electro-optic (EO) Bragg deflectors have been extensively used in a variety of applications. Recent developments show that bandwidths and deflection efficiencies, as well as angular bandwidths, would significantly limit the utilization of EO Bragg deflectors, especially for applications which need strong focusing, such as intra-cavity applications. In this paper, we introduce a broadband EO Bragg deflector based on periodically-poled lithium niobate with a monolithic dual-grating design. We analyzed the deflection properties of this device by using a modified coupled wave theory and showed that this device can be still efficient for a small beam radius under strong focusing, whereas a single-grating one becomes very inefficient. Using a 1064-nm laser beam with a 100-μm beam radius, we obtained a 74% deflection efficiency with a 190-V bias voltage with a 0.5-mm-thick and 7.5-mm-long dual-grating sample. The acceptance angle for the Bragg condition of this device is as large as a few tens of mrad. The potential bandwidth of this device exceeds 500 nm if the proper operation region is chosen.

scholarly journals High Precision Position Measurement Method for Laguerre-Gaussian Beams Using a Quadrant Detector

Sensors ◽  
2018 ◽  
Vol 18 (11) ◽  
pp. 4007 ◽  
Author(s):  
Qian Li ◽  
Jiabin Wu ◽  
Yunshan Chen ◽  
Jingyuan Wang ◽  
Shijie Gao ◽  
...  
Keyword(s):  
Maximum Error ◽  
Least Square ◽  
New Method ◽  
Beam Radius ◽  
Engineering Practice ◽  
Gaussian Beams ◽  
Good Prospect ◽  
Position Measurement ◽  
Beam Position ◽  
Mean Square Errors

In this paper, we propose a new method to improve the position measurement accuracy for Laguerre-Gaussian beams on a quadrant detector (QD). First, the error effects of the detector diameter and the gap size are taken into account, and the position error compensation factor is introduced into the conventional formula. Then, in order to reduce the number of parameters, the concept of effective radius is proposed. Thus, a new analytical expression is obtained with a best fit using the least square method. It is verified by simulation that this approach can reduce the maximum error by 97.4% when the beam radius is 0.95 mm; meanwhile, the root mean square errors under different radii are all less than 0.004 mm. The results of simulation show that the new method could effectively improve the accuracy of the QD measurement for different radii. Therefore, the new method would have a good prospect in the engineering practice of beam position measurements.

Z -scan technique through beam radius measurements

2003 ◽  
Vol 76 (1) ◽  
pp. 83-86 ◽  
Author(s):  
G. Tsigaridas ◽  
M. Fakis ◽  
I. Polyzos ◽  
P. Persephonis ◽  
V. Giannetas
Keyword(s):  
Beam Radius

scholarly journals Study of a non-intrusive electron beam radius diagnostic

1997 ◽  
Author(s):  
T.J.T. Kwan ◽  
B.G. DeVolder ◽  
J.C. Goldstein ◽  
C.M. Snell
Keyword(s):  
Electron Beam ◽  
Beam Radius

scholarly journals Thermal Analysis of Cornea Heated with Terahertz Radiation

2019 ◽  
Vol 9 (5) ◽  
pp. 917
Author(s):  
Wenquan Liu ◽  
Yuanfu Lu ◽  
Rongbin She ◽  
Guanglu Wei ◽  
Guohua Jiao ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Thermal Analysis ◽  
Terahertz Radiation ◽  
Thermal Effects ◽  
Thermal Damage ◽  
Treatment Approach ◽  
Thz Radiation ◽  
Beam Radius ◽  
Corneal Tissue ◽  
Temperature Distributions

We numerically investigate the thermal effects in a cornea illuminated by terahertz radiation. By modifying the bioheat and Arrhenius equations, we studied the heat-transfer and temperature distributions in the corneal tissue, and evaluated the potential thermal damage. The influence of the beam radius and power density are discussed. We also estimated the effective cornea-collagen shrinkage region, and evaluated the degree of thermal damage in the cornea. We expect this work to open up a novel effective and safe thermal-treatment approach based on THz radiation for cornea reshaping in the field of ophthalmology.

scholarly journals Time evaluation of diamagnetic loop and Mirnov oscillations in a major plasma disruption and comparison with a normal shot

2018 ◽  
Vol 9 (1) ◽  
pp. 55-59 ◽  
Author(s):  
R. Sadeghi ◽  
Mahmood Ghoranneviss ◽  
M. K. Salem
Keyword(s):  
Plasma Disruption ◽  
Diamagnetic Loop ◽  
Time Evaluation

scholarly journals Transient fields produced by a cylindrical electron beam flowing through a plasma

2012 ◽  
Vol 30 (3) ◽  
pp. 497-507
Author(s):  
Marie-Christine Firpo
Keyword(s):  
Magnetic Field ◽  
Electron Beam ◽  
Laplace Transform ◽  
Control Parameter ◽  
Bessel Functions ◽  
Skin Depth ◽  
The Other ◽  
Beam Radius ◽  
Equilibrium Situation ◽  
Detailed Computation

AbstractThe out-of-equilibrium situation in which an initially sharp-edged cylindrical electron beam, that could, e.g., model electrons flowing within a wire, is injected into a plasma is considered. A detailed computation of the subsequently produced magnetic field is presented. The control parameter of the problem is shown to be the ratio of the beam radius to the electron skin depth. Two alternative ways to address analytically the problem are considered: one uses the usual Laplace transform approach, the other one involves Riemann's method in which causality conditions manifest through some integrals of triple products of Bessel functions.

scholarly journals Detection of a Semi-Rough Target in Turbulent Atmosphere by an Electromagnetic Gaussian Schell-Model Beam

2019 ◽  
Vol 9 (14) ◽  
pp. 2790
Author(s):  
Xiaofei Li ◽  
Yuefeng Zhao ◽  
Xianlong Liu ◽  
Yangjian Cai
Keyword(s):  
Inverse Problem ◽  
Atmospheric Turbulence ◽  
Turbulent Atmosphere ◽  
Incident Beam ◽  
Radar System ◽  
Equivalent Model ◽  
Laser Radar ◽  
Beam Radius ◽  
Tensor Method ◽  
Set Up

The interaction of an electromagnetic Gaussian Schell-model beam with a semi-rough target located in atmospheric turbulence was studied by means of a tensor method, and the corresponding inverse problem was analyzed. The equivalent model was set up on the basis of a bistatic laser radar system and a rough target located in a turbulent atmosphere. Through mathematical deduction, we obtained detailed information about the parameters of the semi-rough target by measuring the beam radius, coherence radius of the incident beam and the polarization properties of the returned beam.

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