基于相干衰减器的半高斯激光束的产生实验研究

摘要

根据之前的理论分析(Yaling Yin,et al,Opt.Commun.281(22),5511 (2008)),实验上设计了一个由相干衰减器和锋利薄刀片构成的产生无衍射条纹的纯净半高斯激光束的简单光学装置.装置中相干衰减器由两片有机玻璃片和一片塑料薄膜构成,并由马达驱动,该相干衰减器可以有效降低激光场的相干度.实验中,选择氦-氖激光作为实验光源,在传输位置z=0.5 cm处获得了品质因子QSGB=1∶16.42的无衍射条纹的纯净半高斯激光束.实验结果显示,产生的半高斯激光束的品质因子随着传输距离的增加而减少,产生的半高斯激光束的陡峭上升沿的宽度与入射高斯光束的波长和束腰半径无关,这与之前的理论计算结果一致.实验上产生的半高斯激光束因为具有非对称性的强度分布、优良的空间传输特性,所以在现代光学中有广泛的应用.%Based on our former theoretical analysis [Yaling Yin,et al,Opt.Commun.281(22),5511 (2008)],we experimentally design a simple optical device to generate a neat semi-Gaussian laser beam (SGB) without diffraction fringes by using a coherence attenuator and a thin sharp blade.The coherence attenuator is composed of two organic glasses and a piece of plasticfilm rotated by a motor,which can efficiently decrease the coherence of the laser field.In the experiment,we useHe-Ne laser as light source and obtain a 632.8 nm neat SGB without diffraction fringes with a quality factor QsGB =1 ∶ 16.42 at the propagating position z =0.5 cm.The experimental results show that the generated SGB's quality factor decreases with the increasing of the propagating distance.The ascent border width of the generated SGB is independent on the waist radius and wavelength of the incident Gaussian beam,which corresponds well with the theoretical analysis.Our generated SGB can be widely used in modern optics for its asymmetric intensity profile and good propagating properties.