Experimental generation of a neat semi Gaussian laser beam with a coherence attenuator

Abstract

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 plastic film rotated by a motor, which can efficiently decrease the coherence of the laser field. In the experiment, we use He-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.