Selective three-dimensional superposed Laguerre-Gaussian modes in c-cut Nd:YVO4 laser cavities

碩士 === 國立臺灣師範大學 === 物理學系 === 102 === The laser cavity system mentioned in the thesis is different from the traditional solid state laser. We can manipulate the pump offset to generate a variety of the laser beams with complex spatial structures. We investigate the geometric beams generated from a c-...

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Main Author: 賀政浩
Other Authors: 陸亭樺
Format: Others
Language:zh-TW
Published: 2014
Online Access:http://ndltd.ncl.edu.tw/handle/18463616787289225255
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spelling ndltd-TW-102NTNU51980232016-07-02T04:20:54Z http://ndltd.ncl.edu.tw/handle/18463616787289225255 Selective three-dimensional superposed Laguerre-Gaussian modes in c-cut Nd:YVO4 laser cavities 以摻釹釩酸釔雷射晶體產生Laguerre-Gaussian模態疊加之研究 賀政浩 碩士 國立臺灣師範大學 物理學系 102 The laser cavity system mentioned in the thesis is different from the traditional solid state laser. We can manipulate the pump offset to generate a variety of the laser beams with complex spatial structures. We investigate the geometric beams generated from a c-cut Nd:YVO4 laser. The Nd:YVO4 acts as a birefringence crystal. In this work, we focused on six spots of the circular geometric mode. In the far field, the structured laser beam is left-handed circularly polarized and right-handed circularly polarized at the same time. This particular property has many applications, like cold atom system. The phase retardation (δ) of a stable geometric mode can be derived by the birefringence theory. According to the birefringence property of Nd:YVO4, the effective refractive index neff can be calculated by the coefficient ne and no. It leads to get the refraction angle θ of the geometric mode. In the numerical simulation, we fit twelve orders of six spots of circular geometric modes and get the patterns. In the experiment we use the quarter-wave plate (QWP) and the linear plate(LP) to detect the laser polarization. Experimental results reveal that a geometric mode possesses circularly polarized states in opposite directions at the same time and the superposition of orthogonally polarized geometric beams can be generated systematically by controlling the off-axis magnitude. The numerical results have a good agreement with the experimental results. The research may make some contributions for the application of structured beams. 陸亭樺 2014 學位論文 ; thesis 55 zh-TW
collection NDLTD
language zh-TW
format Others
sources NDLTD
description 碩士 === 國立臺灣師範大學 === 物理學系 === 102 === The laser cavity system mentioned in the thesis is different from the traditional solid state laser. We can manipulate the pump offset to generate a variety of the laser beams with complex spatial structures. We investigate the geometric beams generated from a c-cut Nd:YVO4 laser. The Nd:YVO4 acts as a birefringence crystal. In this work, we focused on six spots of the circular geometric mode. In the far field, the structured laser beam is left-handed circularly polarized and right-handed circularly polarized at the same time. This particular property has many applications, like cold atom system. The phase retardation (δ) of a stable geometric mode can be derived by the birefringence theory. According to the birefringence property of Nd:YVO4, the effective refractive index neff can be calculated by the coefficient ne and no. It leads to get the refraction angle θ of the geometric mode. In the numerical simulation, we fit twelve orders of six spots of circular geometric modes and get the patterns. In the experiment we use the quarter-wave plate (QWP) and the linear plate(LP) to detect the laser polarization. Experimental results reveal that a geometric mode possesses circularly polarized states in opposite directions at the same time and the superposition of orthogonally polarized geometric beams can be generated systematically by controlling the off-axis magnitude. The numerical results have a good agreement with the experimental results. The research may make some contributions for the application of structured beams.
author2 陸亭樺
author_facet 陸亭樺
賀政浩
author 賀政浩
spellingShingle 賀政浩
Selective three-dimensional superposed Laguerre-Gaussian modes in c-cut Nd:YVO4 laser cavities
author_sort 賀政浩
title Selective three-dimensional superposed Laguerre-Gaussian modes in c-cut Nd:YVO4 laser cavities
title_short Selective three-dimensional superposed Laguerre-Gaussian modes in c-cut Nd:YVO4 laser cavities
title_full Selective three-dimensional superposed Laguerre-Gaussian modes in c-cut Nd:YVO4 laser cavities
title_fullStr Selective three-dimensional superposed Laguerre-Gaussian modes in c-cut Nd:YVO4 laser cavities
title_full_unstemmed Selective three-dimensional superposed Laguerre-Gaussian modes in c-cut Nd:YVO4 laser cavities
title_sort selective three-dimensional superposed laguerre-gaussian modes in c-cut nd:yvo4 laser cavities
publishDate 2014
url http://ndltd.ncl.edu.tw/handle/18463616787289225255
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