A laser complex amplitude measurement method and system based on coherent diffraction imaging

Abstract

The invention discloses a laser complex amplitude measuring method and system based on coherent diffraction imaging. The measuring method comprises the following steps: establishing an optical measuring system, wherein the optical measuring system comprises a laser, an optical attenuation group, an attenuator, a camera and a motorized translation stage; controlling the camera to move to a positionz1 by the motorized translation stage, and acquiring a D1 surface light spot image of the position z1 by the camera so as to acquire a first light spot image; controlling the camera to move to a position z2 at which the light spot size change can be seen clearly by the motorized translation stage, and acquiring a D2 surface light spot image of the position z2 by the camera so as to acquire a second light spot image; calculating an actual wavefront inclination of the laser; calculating complex amplitude of the first light spot image according to the actual wavefront inclination, an objective function and the second light spot image. The measuring method disclosed by the invention is high in sampling resolution and wide in dynamic range, and the laser complex amplitude can be accurately measured.

Description

technical field [0001] The invention relates to the field of laser complex amplitude measurement, in particular to a laser complex amplitude measurement method and system based on coherent diffraction imaging. Background technique [0002] The phase of the laser is reconstructed through the laser intensity information, so as to realize the measurement of the laser complex amplitude. The measurement method of the laser complex amplitude in the prior art: Although the Shaker-Hartmann wavefront sensor can perform a single sampling of the laser beam to measure the laser complex amplitude, the dynamic range is small and the sensitivity is low, and the reconstructed The phase resolution is based on the number of lenses, and the sampling resolution is low; the traditional interferometric detection method calculates the phase distribution from the interference fringe information, but due to the superposition of the object light and the reference light, the system structure is comple...

AI Technical Summary

Problems solved by technology

The measurement method of the laser complex amplitude in the prior art: Although the Shaker-Hartmann wavefront sensor can perform a single sampling of the laser beam to measure the laser complex amplitude, the dynamic range is small and the sensitivity is low, and the reconstructed The phase resolution is based on the number of lenses, and the sampling resolution is low; the traditional interferometric detection method calculates the phase distribution from the interference fringe information, but due to the superposition of the object light and the reference light, the system structure is complex, and the reference light is required to have High temporal coherence and spatial coherence, high requirements on the resolution of interference fringes and the cleanliness of experimental instruments, make the application of interferometry have many defects; although the classical phase recovery GS algorithm can be measured by two or more The data is iteratively calculated to restore the phase, but the constraints in the GS algorithm combine the actual optical system and the algorithm calculation will introduce errors into the algorithm, and the existence of errors will lead to the failure of the phase reconstruction, and the convergence speed of the GS algorithm increases with The increase of the number of times decreases greatly, and even stagnates, resulting in low measurement accuracy of the complex amplitude of the laser

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