宽频带部分相干光经光栅衍射的光谱变化现象

The Experimental Research on Spectral Change of Partially Coherent Light with Wide-Spectrum-Band Diffracted by a Grating

研究宽频带部分相干光经过光栅衍射后的光谱变化,探讨光谱变化与入射部分相干光的空间相干度、入射狭缝的宽度,以及观测点的位置等关系.结果表明,高斯-谢尔模型(GSM)光束经光栅衍射后,其±1级衍射光束不同位置处的光谱将发生变化,即有的点处光谱将发生红移,有的点处光谱将发生蓝移,并且衍射光束的衍射角与角频率成反比.此外,单缝缝宽越大,GSM光束传播距离越长,光谱宽度Γ值越大,即光谱越宽.最后,从理论上给予论证.

The spectral change of partially coherent light with wide-spectrum-band diffracted by a grating is investigated experimentally, and the influence of the degree of coherence of the incident partially coherent light, the width of the incident slit, and the location of the observation point on the spectral change is studied in detail. It is shown that, spectrum experiences change in different positions of the first order diffractive beam, which is formed as a Gaussian-Schell model （GSM） beam diffracted by a grating, i.e. spectrum is red-shifted in some observation points, and is blue shifted in other observation points, and the diffraction angle of the diffractive beam is inverse proportional to the angular frequency. Moreover, the wider the slit is, the wider spectrum is. Furthermore, spectral change of the first order diffractive beam of GSM beam is theoretically analyzed.