环形光源在干涉仪系统中的应用

Application of ring source in interferometer

介绍了一种新的环形光源技术来抑制干涉仪系统的本征噪声以提高信噪比。阐述了环形光源抑制干涉仪系统本征噪声的原理,根据条纹对比度和需抑制噪声空间频率的要求,推导得到了环形光源的外半径和内半径。通过与传统的点光源对比实验表明:环形光源模式系统的本征噪声峰谷值小于点光源模式,且没有明显的牛顿环噪声,本征噪声的功率谱密度在空间频率小于2.5 mm-1时小于点光源的1/10,系统信噪比在空间频率小于2 mm-1时大于点光源的两倍。

To suppress intrinsic noise and improve signal-to-noise in the interferometric system, a new light source named ring source is described. The reason that the ring source can reduce the intrinsic noise while preserving the fringe contrast of the interferogram is given. Using the fringe contrast and the spatial frequency of the intrinsic noise, the outer and inner radii of the ring source are obtained. Experiments of comparing with traditional point source show that ring source can suppress coherent noise effectively and preserve the fringe contrast. The power spectral density of intrinsic noise is less than one tenth that of point source at spatial frequency less than 2.5 mm^-1 and the signal-to-noise ratio is more than twice that of point source at spatial frequency less than 2 mm^-1.