Simple coherence measurement with a modified Lau interferometer

Abstract

We measure mutual intensity in quasi-monochromatic light. Our setup is simple, without a lens. A rotating grating and a one-dimensional receiver are the only pieces of hardware. The action of our system can be understood as that of a mock Lau interferometer.

Experimental determination of the intensity distribution across a source with a grating interferometer

“…For example, it does not suffer from chromatic aberrations and the use of lenses is not necessary. Hints for further improvements of resolution and performance of systems of this kind can be found in [21].…”

“…Similar procedures were also presented in [20,21], where a rotating grating was used to determine the degree of coherence of a partially coherent light field, but limited to the quasi-monochromatic case.…”

Application of wavelet filtering techniques to Lau interferometric fringe analysis for measurement of small tilt angles

“…have been reported by the author. In recent times, the use of Lau effect/interferometer for measurement of focal length [2], temperature [3,4], refractive index [5], parallelism of the plate [6], degree of coherence [7], small tilt angle [8], etc. has been reported.…”

Automated collimation testing in Lau interferometry using phase shifting technique

“…This conventional Lau set up has been modified by Patorski [2]. Lau set up and its modified form has been used for low-cost measurement of various physical variables such as focal length [3], temperature [4], small tilt angles [5], refractive index [6], parallelism of the plate [7], degree of coherence [8], etc. It has also been used for fabrication of array illuminators [9], theta-encoders [10] and for realization of refractometers for testing the eye-sight [11].…”