光子学报, 2015, 44 (2): 0208001, 网络出版: 2015-02-15
光源相干度对Bessel光最大无衍射距离的影响
Effect of the Light Source Coherence on the Maximum Diffraction-free Distance of the Bessel Beam
光学分析 光学相干性 部分相干Bessel光 最大无衍射距离 相干长度 交叉谱密度 高斯谢尔模型 Optical analysis Optical coherence Partially coherent Bessel beams Maximum diffraction-free distance Coherence length Cross spectral density Gaussian Schell model
摘要
理论分析和实验研究了光源相干度对其产生的Bessel光最大无衍射距离的影响.以He-Ne激光器为光源, 用旋转毛玻璃法产生部分相干光, 经过扩束后再用轴棱锥法产生Bessel光束.通过移动旋转毛玻璃改变部分相干光的相干度, 测量其产生的Bessel光束的最大无衍射距离, 得到光源相干度与产生Bessel光束最大无衍射距离的关系.结果表明, 随着光源相干度的降低, Bessel光束最大无衍射距离明显变短, 当相干度g≈1下降为g=0.8时, 最大无衍射距离缩短了一半.用高斯-谢尔模型进行分析和模拟, 理论模拟结果与实验观察结果基本吻合.
Abstract
Theoretical analysis and experimental research was done on relation between the light source coherence degree and the maximum diffraction-free distance of the generated Bessel beam. A collimated partially coherent beam generated by a rotating ground glass illuminated by a He-Ne Laser was impinged on an axicon to generate partially coherent Bessel beam. Moving the position of a rotating ground glass to change the coherent degree of the light source, and measure the maximum diffraction-free distance of the generated Bessel beam with different coherence degree, the relation between the light source coherent degree and the maximum diffraction-free distance of the generated Bessel beam were obtained. A Gaussian shell model source was used in theoretical analysis and numerical simulation, the results show that the maximum diffraction-free distance suffers a rapid decline when the coherence degree decreased a little. If the coherence degree of the source decreased from g≈1 to g=0.8, the maximum diffraction-free distance will be only a half of the original, the experimental results is coincident with the theoretical analysis.
孙川, 何西, 林炳福, 姜妍, 庄其仁, 吴逢铁. 光源相干度对Bessel光最大无衍射距离的影响[J]. 光子学报, 2015, 44(2): 0208001. SUN Chuan, HE Xi, LIN Bing-fu, JIANG Yan, ZHUANG Qi-ren, WU Feng-tie. Effect of the Light Source Coherence on the Maximum Diffraction-free Distance of the Bessel Beam[J]. ACTA PHOTONICA SINICA, 2015, 44(2): 0208001.