Large-aperture optical element secondary exposure phase measuring device and measuring method

Abstract

The invention discloses a large-aperture optical element secondary exposure phase measuring device and measuring method. The method comprises the following steps: focusing coherent light emitted by a laser after the coherent light passes through a beam expander, forming scattered light spots by a random phase plate after the focused coherent light passes through a focal point, and recording first scattered light spots by a light spot detector; tightly attaching a large-aperture optical element to the front side of a focusing lens, recording second scattered light spots by the light spot detector, performing iterative computation by a computer through the recorded scattered light spots to obtain illuminating light field distribution on the random phase plate, calculating light field distribution on the surface of the focusing lens by using a Fresnel diffraction integral formula, solving light field distribution on the surface of the focusing lens by recovering diffracted light spots recorded by secondary exposure respectively, and solving phase difference, namely the phase difference of a large-aperture optical element to be measured. The large-aperture optical element secondary exposure phase measuring device is not limited to the size of the light spot detector, is low in environmental influence, is simple in structure, is high in measuring resolution, and meets the requirement on the phase measurement of the large-aperture optical element.

Description

technical field [0001] The invention relates to the technical field of phase measurement of a large-diameter optical element of a high-power laser device, in particular to a phase measurement device and method for realizing a phase measurement of a large-diameter optical element by using secondary exposure. technical background [0002] In high-power laser devices, there are thousands of large-aperture optical components on the laser transmission and amplification links. Precise measurement of the phase of large-aperture optical components is crucial to the overall performance of the laser driver. The quality of large-aperture optical components Good or bad is even related to the success or failure of the final physical experiment. Theoretically speaking, the characteristics of these optical components can be precisely measured with a large-aperture interferometer, but there are many difficult problems in actual measurement. For example, if a large-aperture interferometer i...

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Problems solved by technology

[0003] Aiming at the above-mentioned problems of phase measurement of large-diameter optical elements, the present invention proposes a phase measurement device for large-diameter optical elements, which uses a spot detector to record two scattered light spots, and performs iterative calculation by a computer to realize phase measurement of large-diameter optical elements. The method is not limited by the size of the spot detector, less affected by the environment, the device structure is simple, the measurement resolution is high, and it meets the requirements of phase measurement of large-aperture optical elements

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