Method and system for measuring the spatial coherence of a light source

Abstract

A method of measuring spatial coherence of a light source, in particular light from a laser, applicable in optical research and characterization of light sources, in which a light beam is uniformly illuminated by a spatial light modulator (2), on which a phase map composed of two symmetrical diffraction gratings is displayed, with a mask with circular apertures selecting fragments of the light field that propagate through a filtering system, the light beam is subsequently passed through a half-wave plate (6) controlling the division of light intensity after its further passage through a polarizing beam splitter (7), on which the components of the light beam are separated in such a way that one component is reflected by the polarizing beam splitter (7), and the other one passes through the polarizing beam splitter (7) without reflection and is subsequently turned back on mirrors (8,9) returns to the polarizing beam splitter and again passes through it without reflection, while behind the polarizing beam splitter (7) both components propagate along a common optical path and pass through a linear polarizer (10), which on the detector (11) controls the contrast of interference fringes created by the interference of light beams coming from different circular apertures of the spatial light modulator (2). The system for measuring the spatial coherence of a light source, composed of a lighting system and a detector, in front of which a linear polarizer controlling the contrast of interference fringes on said detector is located, is characterized in that behind the lighting system (1) there are located a spatial light modulator (2), a filtering system, behind which the polarizing beam splitter (7) is located,in front of which there is a half-wave plate (6) controlling the division of the light intensity after it passes through the polarizing beam splitter (7) and behind which there are mirrors (8, 9) that return one component of the light beam transmitted through it to it, as well as the said linear polarizer (10) and detector (11) on the common optical path of both components of the light beam,