APPARATUS FOR MEASURING PHYSICAL PROPERTIES OF A SAMPLE

摘要

An instrument for measuring a physical property of a sample by optically detecting the response of the sample to projection of an ultra-short optical pulse. A Sagnac common-path optical interferometer for measuring a physical property at a vertical input angle is provided. The interferometer is a two- arm Sagnac type and has three beam splitters. A sample (14) is excited by an ultra-short optical pulse, and changes of the strength and phase of the optical beam caused by the excitation are measured. Therefore it is possible to measure a physical property in a wide range such as the thickness of an object, a sound speed, or a thermal property.