Fischer E, Dalhoff E, Heim S, Hofbauer U, Tiziani H J
Appl Opt. 1995 Sep 1;34(25):5589-94. doi: 10.1364/AO.34.005589.
We propose an interferometric method for measuring absolute distances larger than the wavelength. A laser diode is used as a light source. The principle of operation is based on multiple-wavelength interferometry that uses a modulated light source. This method uses the fact that the wavelength of light emitted by the laser diode can be varied by means of the injection current. The modulation of the injection current in combination with the optical heterodyne technique causes a high-frequency phase-modulated detector signal. The phase deviation of the signal is a measure of the optical path difference in the interferometer. By FM demodulation of the detector output with a phase-locked loop demodulator, the optical path difference can be determined directly without the classical ambiguity problem of interferometry. The measuring range in the experiments was limited to 50 mm by the maximum travel range of the used specimen translation stage. Because of the inherent light sensitivity of the method described, the rangefinder can be used for three-dimensional profile measurements on a wide variety of objects, even on diffuse scattering surfaces.
我们提出了一种用于测量大于波长的绝对距离的干涉测量方法。使用激光二极管作为光源。其工作原理基于使用调制光源的多波长干涉测量法。该方法利用了激光二极管发射的光的波长可通过注入电流来改变这一事实。注入电流的调制与光学外差技术相结合会产生高频相位调制的探测器信号。信号的相位偏差是干涉仪中光程差的一种度量。通过使用锁相环解调器对探测器输出进行调频解调，可以直接确定光程差，而不会出现传统干涉测量法中存在的模糊问题。在实验中，测量范围受所用样品平移台的最大行程限制，为50毫米。由于所述方法固有的光敏感性，该测距仪可用于对各种物体进行三维轮廓测量，甚至可用于漫散射表面。
