实时测量表面形貌的正弦调制半导体激光干涉仪

Sinusoidal Phase Modulating Laser Diode Interferometer for Real-Time Surface Profile Measurement

设计了一种实时测量表面形貌的正弦相位调制半导体激光干涉仪,对其抗干扰的实时测量原理进行了分析.在该正弦相位调制干涉仪中,利用高速图像传感器探测干涉信号,该干涉信号通过信号处理电路实时鉴相得到被测表面所对应的相位分布,即可实时获得待测量物体的表面形貌.在实验中,测量了楔形光学平板的表面形貌,测量点为30×30个,测量时间小于10 ms,重复测量精度为4.3 nm.实验结果表明该正弦相位调制干涉仪的有效性.

The optical interferometry for the surface profile measurement, with an ability of high-accuracy and non-contact measurement, has a wide application in industrial production and scientific research. In this paper, a sinusoidal phase modulating（SPM） interferometer to realize real-time surface profile measure- ment is proposed,and its measurement principle is analyzed theoretically. In the SPM interferometer, the interference signal is detected by a high speed image sensor based on a low-speed CCD and discriminated by a signal processing circuit to obtain the phase of each measurement point on the surface. In experiments, the surface profile of an optical wedge was measured by the interferometer. For 30× 30 measuring points, the measurement time is less than 10 ms, Repeatability of the measurement is 5.2 nm. The usefulness of the interferometer is verified by the experimental results.