白光相衬实验

在相衬实验中,设相板中心波长使相板有π/2的相移,通过理论分析,得到:(1)单色光波长偏离相板中心波长越远,相衬像对比度越低;(2)准单色光相衬像对比度与谱带宽度及准单色光波长与相板中心波长偏移量有关;(3)在一定条件下,白光相衬像的光强分布与相应的单色光相衬像的光强分布一致.若选择合适的实验条件,可使像对比度取最大值.实验结果与理论一致.

THE WHITE LIGHT PHASE CONTRAST EXPERIMENT

Supposing that in the phase contrast experiment the central wavelength of a phase disk makes itself have a phase shift ofttttttttttttt/2, it is abtained in theoretical analysis that ( 1 ) the more the wavelength of monochromatic light deviates the central wavelength of the phase disk) the lower the visibility of the phase contrast image; ( 2 ) the visibility of the phase contrast image for quasimonochromatic light is related to the width of the spetrum and the deviation between the wavelength of the quasimonochromatic light and the central wavelength of the phase disk, and ( 3 ) intensity distribution of the phase contrast image of white light, in a given condition, is the same as one of the corresponding monochromatic light. With suitable experimental condition) the visibility of the image will reach its maximun. Experimental results prove principle explaining the white light phase contrast to be correct, the experimental method simple, the operation convenient, and the effect obvious.