Measurement of evanescent field by Michelson interferometer

We present a method to measure the evanescent field by Michelson interferometer. The optical fiber probe is glued on a piezoelectric bimorph, and the initial position between the tip and the sample surface is controlled based on shear force detection method. With the decrease of the voltage applied on the PZT tube, the tip-sample distance is controlled, at same time the optical intensity of evanescent field generated by total internal reflection is detected by a photomultiplier, the function of evanescent filed intensity-distance between probe and sample surface can be obtained. This kind of device is simple and easy to operate; also it has the advantage of high reliability.