Microinterferometer For Distance Measurements

Abstract

Several embodiments of a microinterferometer are disclosed. A first embodiment of a microinterferometer for measuring the absolute distance to an object surface includes a substrate. The microinterferometer also includes a phase-sensitive, reflective diffraction grating formed on the substrate. The diffraction grating is configured to reflect a first portion of an incident light and transmit a second portion of the incident light, such that the second portion of the incident light is diffracted. The microinterferometer further includes a lens formed on the substrate for focusing the second portion of the incident light to a predetermined local distance, and a photo-detector for receiving interference patterns produced from the first portion of the incident light reflected from the diffraction grating and the second portion of the incident light reflected from the object surface.