包括有相位衍射光栅的干涉仪将光学精度引向高斜率的平面度测试。光栅将单光源输出分成两段光束，在测试中又将两股光束合并在一起。反射光束产生的干涉图与具有实际光源尺寸10倍波长的光源所产生的图形相等，从而提出系统“等效波长”的概念。光栅于涉仪的等效波长大于可见波? An interferometer including a phase diffraction grating directs optical accuracy to a high-slope flatness test. The grating splits the single light source output into two beams, which in turn combine the two beams together. The reflected light beam produces an interference pattern equal to the one produced by a light source with a wavelength of 10 times the actual light source size, giving rise to the concept of a system “equivalent wavelength.” Grating in the equivalent wavelength is greater than the visible wave?