Device and method for dynamically measuring transparent material under femtosecond laser loading

Abstract

The invention belongs to the technical field of optical measurement, and particularly discloses a device and method for dynamically measuring a transparent material under femtosecond laser loading. The device comprises a femtosecond laser, an unpolarized beam splitter, a femtosecond pulse pumping module, and a picosecond pulse detection module, wherein thefemtosecond laser and the unpolarized beamsplitter are arranged in sequence; laser emitted by the femtosecond laser is divided into two paths of femtosecond pulse laser through the non-polarization beam splitter; one path enters a pump lightpath, after frequency multiplication by a light beam frequency multiplication unit, a single femtosecond pulse is obtained through a mechanical shutter, and the single femtosecond pulse enters a focusing lens and is focused in a to-be-measured sample; the other path of femtosecond pulse laser enters a detection light path and is broadened into linear chirped picosecond pulses by a chirped broadening unit, the linear chirped picosecond pulses are introduced into a to-be-detected sample through an imaging lens group, an excitation region is amplified and then enters an imaging spectrometer, anda CCD camera collects images in the imaging spectrometer. The space-time evolution process of structural modification in the transparent material under femtosecond laser loading can be obtained in asingle pulse.

Description

technical field [0001] The invention belongs to the technical field of optical measurement, and more specifically relates to a dynamic measurement device and method for transparent materials under femtosecond laser loading. Background technique [0002] When the femtosecond laser pulse is focused inside the transparent material, due to the extremely high energy density, ultra-short action time and limited action space, the structure and physical properties of the material in the focal area will be changed in the picosecond time range or even femtosecond time range . Due to its short action time, the heat generated by the laser has not yet been transmitted to the material lattice, and the loading is over, so it will not affect the material outside the focal area. Thanks to this, the femtosecond laser is widely used in the micro-processing industry, especially For transparent materials, precise fixed-point micromachining inside the material makes it widely used in the fields ...

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Problems solved by technology

However, the above two methods are based on multiple pulse measurements, which have high requirements on the stability of the experimental system, are easy to introduce system errors, and the measurement process is cumbersome and the measurement period is long.

Obviously, the above methods cannot satisfy the real-time in-situ measurement of the processing area during femtosecond laser processing.

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