干涉成像系统传递函数的数值分析

？干涉仪系统传递函数能有效地表征系统相位成像的性能。通过假设干涉成像系统是复振幅的线性平移不变系统，模拟计算正弦相位光栅和相位台阶这两类标准相位物体的成像，确定干涉仪系统传递函数。数值分析结果表明：系统传递函数随着波像差的增加而减小；干涉成像系统对小幅度相位（远小于1rad）成像是近似线性的，而对大幅度相位(大于0.5rad）成像则是明显非线性的。当正弦相位的幅度为1时，系统传递函数在1/2和1/3截止频率处出现明显的急剧下降。高度为π/2的相位台阶成像时，系统传递函数随着空间频率的增加而缓慢地降低。theperformanceofphaseimagingininterferometricimagingsystemiswellcharacterizedbythesystemtransferfunction(stf).thestfoftheinterferometricimagingsystemisanalyzednumericallybyassumingthatthesystemislinearandshift-invariantforthecomplexfield.twostandardphaseobjects,？sinusoidalphasegratingandphasestep,？areemployedandsimulatedtodeterminethestf.numericalsimulationresultsshowthatthestfdecreasesasthewavefrontaberrationofinterferometricimagingsystemincreases.italsoshowsthattheinterferometricimagingsystemisapproximatelylinearforsmallphase(farlessthan1rad)butexplicitlynonlinearforlargephase(largerthan0.5rad).thestfhasavisibledropatonehalforonethirdofthecut-offfrequencyoftheimagingsystemwhentheamplitudeofsinusoidalphaseis1rad.foraphasestepwithaheightofπ/2rad,？thestfhasnovisibledropbutdecreasesslowlywiththeincreasingofspatialfrequency.theresultsprovideausefulguidancetothedesignofinterferometerandthemeasurementofstfandpowerspectrumdensityinexperiment.