Ultrafast digital speckle system based on pulse laser and experimental method

Abstract

The invention discloses an ultrafast digital speckle system based on pulse laser and an experiment method. The system comprises a pulse laser, a spectroscope, a reflector group, a beam expander group, loading equipment and an ultrafast camera which are sequentially arranged along a light path. The spectroscope is used for splitting laser output by the pulse laser into two beams of laser with equal light intensity; the ultrafast camera is used for shooting digital speckle images; the frame rate of the ultrafast camera is consistent with the repetition frequency of the laser, and the exposure time of the system is consistent with the picosecond-order full width at half maximum of the laser output by the pulse laser. According to the invention, the time resolution of a material strain field is improved to picosecond magnitude, so that the digital speckle technology can be well applied to high-strain-rate scenes such as fracture and impact; fast moving feature points on the test piece can be clearly shot, and the test precision of the digital speckle technology is greatly improved; and the frame rate of the ultrafast camera and the frame rate of the picosecond laser are set to be the same value, so that an equipment synchronization program commonly existing in the laser pulse test process is saved.

Description

technical field [0001] The invention relates to the technical field of optics and digital images, in particular to an ultrafast digital speckle system and an experimental method based on pulsed laser. Background technique [0002] The digital speckle technology calculates its displacement by tracking the position of a certain feature point in the two images before and after the surface deformation of the object, and then integrates the displacement characteristics of all the feature points on the specimen to obtain the strain field of the specimen. As a non-contact testing method, it is widely used in civil engineering, material properties, non-destructive testing and other research fields. With the development of social economy, more and more engineering needs to study the whole process environmental strain diagram under the condition of high strain rate (such as blasting and impact). [0003] Currently, digital speckle techniques use continuous light sources. When applie...

AI Technical Summary

Problems solved by technology

When applied to a scene with an ultra-high strain rate, the feature points on the specimen will be severely blurred, resulting in inaccurate or even impossible calculation results when the displacement characteristics of all feature points on the specimen are integrated and calculated.

Images