Abstract

A new method for determining the chirp of a femtosecond broadband IR laser pulse at a central wavelength of 2.5 μm, based on the generation of a spectral supercontinuum in the field of a spectrally limited femtosecond laser pulse, propagating in a single mode fiber based on chalcogenide glass, and subsequent noncollinear generation of radiation at summary frequency by spectrally limited and spectral broadened supercontinuum femtosecond pulses is proposed. The time dependences of the instantaneous frequency of a femtosecond broadband pulse, obtained both from the results of numerical integrations of the equation describing the process of spectral supercontinuum generation and from the results of two-dimensional distributions of dynamic spectrograms are presented. It is shown that the proposed method allows one to determine the chirp of a broadband femtosecond IR laser pulse, formed during the soliton propagation mode in a fiber, with a relative error of no more than 5%, but the chirp of a broadband femtosecond IR laser pulse, formed in the process of non-soliton propagation in a fiber, with a relative error of no more than 10%.The presented results can be used in the development of a nonlinear optical phase correlator for determination the phase and time profile of a femtosecond laser pulse in the mid-IR range.

中文翻译：

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确定红外范围内飞秒宽带激光脉冲the的非线性光学方法

摘要

基于在光谱受限的飞秒激光脉冲领域中产生的光谱超连续谱，在基于硫族化物的单模光纤中传播的方法，确定中心波长为2.5μm的飞秒宽带IR激光脉冲的the的新方法提出了通过频谱限制和频谱加宽的超连续飞秒飞秒脉冲随后在汇总频率处非共线辐射的提议。飞秒宽带脉冲瞬时频率的时间相关性，从描述光谱超连续谱生成过程的方程的数值积分结果和动态频谱图的二维分布结果中获得。