排序方式: 共有13条查询结果,搜索用时 15 毫秒
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非傍轴厄米-正弦-高斯光束的特性 总被引:1,自引:0,他引:1
为了研究厄米-正弦-高斯(HSiG)光束在非傍轴情形下受参量影响的特性,基于光强二阶矩理论,经过一系列复杂的数学计算,得出了非傍轴厄米-正弦-高斯光束的远场发散角、束腰宽度以及光束传输因子的解析式,并通过数值模拟,得到了它们与离心参量的关系。结果表明,在束腰宽度与波长比取值逐渐减小时,随着离心参量趋于0,当阶数为奇数和偶数时.发散角分别趋于63.435°和73.898°。束腰宽度和光束传输因子随参量的增加呈现较大的起伏,非傍轴情形下的光束传输因子取值与傍轴情况有很大的不同,其受参量影响不仅可以小于1,甚至趋于0。 相似文献
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The interaction of the Lissajous singularity and singular Lissajous line carried by non-paraxial polychromatic beams is studied. It has been found that with propagation the singular Lissajous line breaks into more than two Lissajous singularities, pairs creation and annihilation of Lissajous singularities, the handedness reversal and change in the degree of polarization of Lissajous singularities, as well as the change in the shape of Lissajous figures may take place. 相似文献
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标量衍射理论的非傍轴修正 总被引:1,自引:1,他引:0
当光束具有较大的发散角或光束束腰可与波长相比拟时,傍轴近似不再成立.用微扰级数法处理非傍轴光束的传播问题,数值计算发现,对受硬边光阑限制的光束,由于高频分量的贡献,当传输距离较大时,高阶级数解的修正效果不好,甚至失效,级数解的有效范围将受到很大限制.在标量衍射理论角谱表示的基础上,以平面波圆孔衍射为例,给出了衍射场的非傍轴修正解,得到的非傍轴修正解避免了级数解本身在数学上的发散性问题,并在一定条件下,可过渡到级数解,并且指出在近场或非傍轴区对傍轴解进行高阶修正的必要性和有效性. 相似文献
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Guoquan Zhou 《Journal of Modern Optics》2013,60(7):910-918
The non-paraxial TM polarized Gaussian beam, which approximately reduces to be a Gaussian TEM00 mode at the paraxial case, is the rigorous solution of Maxwell's equations for a confocal resonator. By means of mathematical techniques, the analytical expression in the source region has been derived without any approximation and expressed as a sum of the propagating part and the evanescent part. With some certain given values of the initial Gaussian half width w 0, the distributions of the squared modulus of the propagating part, the evanescent part, and the whole beam are depicted in the reference plane close to the source. When w 0 is small enough, the squared modulus of the non-paraxial TM polarized Gaussian beam is composed of two lobes, which results from the contribution of the evanescent wave. This research further reveals the difference of a non-paraxial TM polarized Gaussian beam from a non-paraxial Gaussian beam. 相似文献
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基于小衍射源和衍射远场的特点,简化了瑞利-索末菲标量衍射积分公式,并应用于分析非傍轴衍射光束的衍射远场总功率和光束传输因子特性。由于物理概念上的空间频谱的定义域局限在一定范围,基于此计算的非傍轴衍射光束的衍射远场总功率不满足能量守恒定律,基于此计算的非傍轴衍射光束的光束传输因子也与常识不符。当采用数学概念上的空间频谱分析上述特性时,两个符合常识的规律被重提,并以非傍轴基模高斯光束衍射远场总功率和光束传输因子的相对计算误差说明上述结论。 相似文献
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为了研究电场一定时,光束在非近轴条件下铌酸锂晶体的电光效应,采用折射率椭球张量的循环坐标变换方法,理论上推导了光轴正交截面上折射率分布的解析式,讨论了折射率、相位延迟以及透射率与光束入射方向之间的关系,并且进行了实验验证,取得了透过率随光束与光轴夹角α的实验数据。结果表明,y方向加电场时,入射光小角度偏转将引起x方向感应折射率以及光束透射率的明显变化,而y方向的感应折射率不变;光束与光轴的夹角α对铌酸锂晶体电光性能的影响远远大于光矢在x-y平面与x轴正半轴的夹角β对其的影响;x方向加电场时感应折射率同y方向加电场时类似,但此时相位延迟更小,在0°~0.4399°夹角范围内,前者的透过率变化较后者慢,并且在0.45°之后呈现出交替变化的规律,当夹角为0.5°,0.680°等位置时,它们具有相同的透过率。这一结果对利用角度调节以改善铌酸锂晶体的电光性能具有一定的指导意义。 相似文献
7.
Sivakumar Gayathri G. Sreevidya Varma Gagandeep Singh Bannur Nanjunda Shivananju S. Sridevi Siva Umapathy 《International Journal of Optomechatronics》2017,11(1):27-35
The reversible photostriction (photomechanical strain) in Ge35S65 chalcogenide thin film deposited by a solvent casting method has been monitored using a fiber Bragg grating (FBG) sensor. The shift in Bragg wavelength is used as a probing parameter to quantitatively measure the photoinduced strain arising because of structural modifications in these films under illumination. Exposure to band gap light (405?nm) and above band gap light (302 and 254?nm) leads to a reversible photostriction effect of the order of 100?µε. The present study shows that FBG sensors can be used to effectively measure the optomechanical actuation in chalcogenide films caused by the reversible photostriction effect in the visible and ultraviolet wavelength region. 相似文献
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非傍轴截断双曲余弦高斯光束的M2因子 总被引:3,自引:2,他引:1
基于功率密度的二阶矩方法,对非傍轴截断双曲余弦高斯(ChG)光束的束宽、远场发散角和M2因子进行了研究.数值计算结果表明,非傍轴截断ChG光束的M2因子不仅与截断参数δ、偏心参数α有关,而且与初始束腰宽度和波长之比w0/λ有关.在δ足够小时,M2因子可小于1.当δ→ 0时,远场发散角趋于渐近值63.435°.对于α=0(Ω0=0)和δ→∞的特例,我们的结果分别退化为非傍轴截断高斯光束和非傍轴无截断ChG光束的M2因子. 相似文献
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