Interferometer

Abstract

An interferometer including an analysis optical system including a retroreflector configured to reflect analysis light and a first light receiver configured to receive the analysis light and output a first light reception signal, the analysis optical system irradiating a sample with the analysis light and causing the analysis light to interfere; a length measuring optical system including a laser light source configured to output laser light, an optical modulator configured to modulate a frequency of the laser light by using a vibrator and add a modulation component to the laser light, and a second light receiver configured to receive the laser light containing the modulation component and a length measurement component generated when the retroreflector is irradiated with the laser light and output a second light reception signal, the length measuring optical system causing the laser light to interfere; and a driver configured to change a position of the retroreflector.

Dependencies are inferred from the claim text.