为实现用小口径面形干涉仪完成对大口径光学镜面面形的检测,发展了斜入射检测方法,增大投射到待测镜上光斑的尺寸,从而增大干涉仪检测的镜面口径范围。推导了斜入射法检测平面反射镜面形的公式,并考虑了此方法可能引入的误差。对尺寸为124 mm×42 mm的平面反射镜分别在垂直和不同斜入射角条件下进行了测量,垂直入射时测得镜子工作表面面形起伏高度均方根(RMS)和峰谷(PV)值分别为16.3 nm和67.8 nm,斜入射时测得镜子工作表面的面形起伏高度RMS和PV值分别为16.8 nm和68.7 nm,相对误差分别为3%和0.9%,可以满足第三代同步辐射光束线的要求。 In order to realize the detection of large-aperture optical specular shape with a small aperture surface interferometer, an oblique incidence detection method is developed to increase the size of the spot projected onto the mirror to be measured, thereby increasing the specular aperture range detected by the interferometer. The formula for detecting the plane mirror profile by oblique incidence method is deduced, and the error that this method may introduce is considered. The plane mirrors measuring 124 mm × 42 mm were measured under normal and different oblique incident angles respectively. The RMS and the valley (PV) of the working surface were measured at the vertical incidence, The values ​​of RMS and PV were respectively 16.8 nm and 68.7 nm and the relative errors were 3% and 0.9%, respectively, at the oblique incidence of the mirror, which can meet the third generation of synchronization Requirements for radiation beamline.