Tightly focused epimicroscope technique for submicrometer-resolved highly sensitive refractive index measurement of an optical waveguide

摘要

We introduce a very sensitive new configuration, to the best of our knowledge, in an optical microscope system that utilizes two detectors: one is to measure the power of a low reflected signal from a sample, and the other is only to monitor the confocal geometry of the system. With this new configuration, we could effectively remove measurement noise associated with small perturbation in measurement conditions such as surface curvature, tilt, and vibration in a microscope system. We have obtained a high-resolution relative index precision of 9 X 10~(-5) by employing this novel technique with two detectors.