光学元件表面的数字全息在线检测

针对光学元件表面质量在线检测的特点,设计了基于数字全息的三维再现检测系统.该系统采用离轴光路,避开了被测元件的光轴,在数字全息再现过程中应用倾斜相差补偿技术去除了由于离轴检测引入的倾斜相位畸变.在检测过程中,利用围绕光轴旋转被测元件的方法来改变入射照明光方向矢量和相应的观察方向,实现了多照明矢量合成孔径技术的应用,扩展了系统的检测距离,提高了系统分辨率.同时,多照明角度下检测数据的叠加,还有效地抑制了检测过程中出现的散斑噪声对结果准确度的影响.通过对分辨率板、高精度玻璃反射镜的检测实验,验证了该系统在光学元件表面检测中的作用.当记录距离为40 cm时,其分辨率能够达到10 μm,满足光学元件表面检测的需要.

Digital holographic on-line detection of optic component surface

An on-line 3D detection system for optic component surface measurement was designed based on digital holography.An off-axis structure was chosen to evade the optical axis of a test object and the tilt phase compensation was used to eliminate the tilted phase distortion caused by an off-axis optic path.In this system,the illuminating angle and view direction could be changed by rotating the object around the optical axis,by which the recording distance was increased and the resolution was improved using synthetic aperture technique.Meanwhile,the superposition of reconstruction images could decrease the effect of speckle noise on the reconstructed distribution.The proposed method is experimentally validated by a resolution test target and an optic mirror,and it shows that the 2D resolution of the system has been 10 μm at a recording distance of 40 cm and the system noise also be suppressed effectively.