Method for acquiring space-time-frequency information of ultra-short pulse laser far-field focal spot

Abstract

The invention discloses an ultra-short pulse laser far-field focal spot space-time-frequency information acquisition method, and aims to solve the technical problem that chromatic aberration of an existing transmission-type amplification imaging system causes change of far-field focal spot distribution of amplification imaging relative to a target point position. The method comprises: acquiring interference images of a focal plane position, at least one positive defocusing position and at least one negative defocusing position of a measured ultra-short pulse laser through an interference imaging spectrometer; respectively processing each interference image by adopting an interference spectrum imaging technology to obtain corresponding focal spot intensity space-frequency information; reconstructing far-field focal spot space phase two-dimensional information under each frequency in the measured ultra-short pulse laser through a phase recovery technology based on all the obtained focalspot intensity space-frequency information; and finally, reconstructing the obtained two-dimensional information of the spatial phases of all the far-field focal spots according to the size sequence of the frequency to obtain time-space-frequency information of the far-field focal spot phases of the ultra-short pulse laser.

Description

technical field [0001] The invention relates to a method for acquiring time-space-frequency information of an ultrashort pulse laser far-field focal spot. Background technique [0002] Since the ultrashort pulse laser has wide spectral characteristics, the beam passes through multiple transmission elements (especially the lens elements) in the device during transmission, which will cause large chromatic aberration. This chromatic aberration will expand the laser far-field focal spot of the target point to several times the diffraction limit, which is not conducive to the pursuit of a laser focal spot near the diffraction limit. At the same time, the introduction of residual chromatic aberration also reduces the convergence ability of the far-field focal spot. Accurate measurement of ultrashort pulse laser far-field focal spot is the premise of in-depth precision physical experiments. Through accurate measurement results, further optimization of the beam is formed, thereby gr...

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Problems solved by technology

[0004] The present invention aims to solve the technical problem that the chromatic aberration of the transmission magnification imaging system in the prior art will cause the far-field focal spot distribution of the magnified imaging to change relative to the far-field focal spot position of the target point, and provides an ultra-short Method for Acquiring Time-Space-Frequency Information of Pulsed Laser Far-field Focal Spot

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