High-precision methods and devices for in situ measurements of thermally induced aberrations in optical elements

Abstract

An optical system that comprises two devices for remote measurements, a broadband optical interferometer and a scanning Hartmann sensor, is described. The results of simultaneous measurements with both devices and the results of numerical modeling of sample surface heating are presented.

Interferometry based technique for intensity profile measurements of far IR beams

“…It should be noted that an alternative measurement of the CO 2 -laser irradiation profile was performed by means of a chink diaphragm scanning the beam that is directed at the bolometric power meter. Such a measurement was described by Zelenogorsky [9]. It is significant that this method expects a rather long measuring time (time for shift of the diaphragm plus responding time of the power meter in each point) apart from averaging the profile along the direction of the chink.…”

“…The reflected beams are spatially matched in a wavefront conjugation unit 11 that consists of two semitransparent mirrors 12 and 13. Unwanted reflections from the conjugation unit 11 are filtered out by an angular This interferometer makes phase-modulated measurements of the optical thickness of a sample with record-breaking accuracy ͑ϳ͞1000͒ [9]. To achieve this, the path-length difference between interfering rays is mechanically varied using displacement of the mirror 12 in the conjugation unit 11 (see Fig.…”

TSAG-based cryogenic Faraday isolator

“…Optical power of thermal lens was measured using phase-shift interferometric method described in [33]. Experimental setup is shown in Fig.…”

“…To find spatial distribution of phase distortion series of interferograms with different positions of the mirror 3 were recorded, after that interferometric pictures were processed by the algorithm proposed in [33]. Profiles of the phase distortion were recorded without heating radiation and with heating radiation at several power levels.…”

Interference scheme with transverse shift of beams for remote precision monitoring of parameters of optical elements

“…Previously, remote-monitoring interference schemes allowing one to perform high-accuracy measurements of the optical thicknesses of elements by using the rays reflected from two faces of an element were proposed in [5,6]. One of such schemes is shown in Sec.…”