Broadband optical parametric amplification method and device based on cascaded crystal

Abstract

The invention belongs to the technical field of ultrafast laser, and discloses a broadband optical parametric amplification method and device based on a cascaded crystal. The broadband optical parametric amplification method comprises the following steps: dividing the initial femtosecond laser into two beams, wherein the weaker beam passes through a pre-amplification stage to generate broadband seed light of a near-infrared band; the stronger beam acts as pumping light. The pumping light adjusts the time delay through a time delay line to be synchronous with the seed light in a time domain, and the pumping light and the seed light are combined by a dichroic mirror and are input into the cascade crystal together for optical parametric amplification. The cascade crystal comprises three II-type phase-matched barium borate crystals, the thicknesses and the phase matching angles of the three II-type phase-matched barium borate crystals are different, and the three II-type phase-matched barium borate crystals are used for amplifying different wave bands of the seed light. Through the amplification of the cascaded crystal, a broadband idler frequency spectrum can be efficiently obtained in a middle infrared band, and then the broadband idler frequency spectrum is compressed by a pulse compressor to finally obtain an ultrashort idler frequency light pulse with a period magnitude and astable carrier envelope phase.

Description

technical field [0001] The invention relates to the field of ultrafast laser technology, in particular to a cascaded crystal-based broadband optical parametric amplification method and device. Background technique [0002] Period-level high-energy femtosecond laser pulses have broad application prospects in ultrafast optics and other fields. In recent years, thanks to the advantages of wide gain bandwidth, high frequency tunability, and no thermal effect accumulation of Optical Parametric Amplification (OPA), based on this technology, it has been widely used in visible light, near-infrared and mid-infrared bands. Period-level ultrashort laser pulses are generated within a tunable range. Therefore, the optical parametric amplification system has become the preferred solution for down-converting the frequency of Ti:Sapphire femtosecond lasers. [0003] Optical parametric amplification uses a beam of high-intensity, high-frequency pump light to amplify a beam of low-intensity...

AI Technical Summary

Problems solved by technology

In contrast, the nonlinear coefficient of the crystal under the condition of type II phase matching is high, which is beneficial to improve the energy conversion efficiency of the system, but limited by the bandwidth of the phase matching, the bandwidth of the output spectrum is often not as good as that of the type I phase matching

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