Ultra-wideband ultra-short pulse measuring device and measuring method based on two-dimensional material

Abstract

The invention discloses a non-collinear ultra-short pulse measuring device and measuring method capable of working in a wide spectrum band based on few-layer two-dimensional materials. According to the device, pulse light to be measured is divided into two paths through a first beam splitter; after being reflected by a corner reflector and a controllable delay angle, one path of the pulse light reaches a second beam splitter to be reflected; after passing through a first focusing lens, the light is obliquely focused on a few-layer nonlinear two-dimensional material with broadband response at an opposite included angle; after the light is reflected and passes through the same first focusing lens, a generated autocorrelation optical frequency-doubled signal light and other optical signals have separated spatial distribution characteristics, and the autocorrelation optical frequency-doubled signal light can be separated only by using a small-hole diaphragm. Autocorrelation optical frequency doubling signal light spectrum information under different time delays is recorded, and complete information of the pulse to be measured is restored after a certain iterative computation is carriedout by an FROG algorithm. According to the invention, the problem that different incident angles need to be adjusted for different incident wavelengths in the prior art can be solved, the ultra-fastpulse of a broadband can be measured, the pulse broadening caused by the thickness of a nonlinear material in the prior art is also avoided, and more accurate ultra-short pulse measurement is realized.

Description

technical field [0001] The invention relates to the technical field of laser pulse measurement, in particular to a two-dimensional material-based ultra-broadband ultra-short pulse measurement device and measurement method. Background technique [0002] Due to the extremely high light intensity and extremely short pulse width of the ultrashort pulse, it is widely used in the field of scientific research and precision processing. The progress of ultrashort pulse technology is inseparable from the development of pulse measurement technology. Since the space-time distribution of ultrashort pulse laser also has a major impact on the application of ultrashort pulse laser, in some applications we must accurately know the pulse laser The spatio-temporal characteristics in the process of generation, transmission and transformation can reveal its physical mechanism and establish a reasonable theoretical model. More and more studies have shown that the analytical study of the fine str...

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Problems solved by technology

[0004] The usual pulse measurement device uses a frequency doubling crystal as a nonlinear medium. This method needs to adjust different incident angles for different incident wavelengths to achieve the necessary phase matching of the frequency doubling crystal. Therefore, it is impossible to measure wide-wavelength lasers, and The existence of a certain thickness of the crystal will introduce dispersion to the measured pulse, resulting in pulse broadening and affecting the measurement accuracy

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