Mid-infrared femtosecond pulse laser

Abstract

The invention discloses a mid-infrared femtosecond pulse laser which comprises an ytterbium-doped fiber oscillator, a pulse stretcher, a spectrum shaping module, a crystal regenerative amplifier module, a pulse compressor, a second-order cascade nonlinear compressor module and a pulse internal difference frequency module which are arranged according to an optical path sequence. The ytterbium-doped fiber oscillator is used for generating initial laser pulses; the spectrum shaping module is used for performing spectrum shaping on the broadened laser pulse and generating a first laser pulse; the crystal regenerative amplifier module is used for amplifying the first laser pulse; the compressor module is used for carrying out nonlinear compression on the amplified and linearly compressed first laser pulse to generate a second laser pulse; the in-pulse difference frequency module is used for generating a third laser pulse of a middle infrared band from the second laser pulse through nonlinear conversion; and according to the invention, the structure of the laser is greatly simplified, the output efficiency of the pump pulse is improved, the wavelength tuning range of the mid-infrared femtosecond laser is expanded, and the cost of the mid-infrared femtosecond laser is reduced.

Description

technical field [0001] The invention relates to the field of solid-state ultrafast lasers, in particular to a mid-infrared femtosecond pulsed laser. Background technique [0002] Due to the lack of gain media in the mid-infrared band, nonlinear parametric down-conversion is the only way to generate femtosecond pulses in the mid-infrared, especially at wavelengths above 4 μm. Among them, the intra-pulse difference frequency does not need to construct signal pulses, which is a compact and simple technology for generating mid-infrared femtosecond pulses. However, the intra-pulse difference frequency requires that the pump pulses cover both the spectral range of the pump and signal pulses. Therefore, for a high-power Yb-doped laser, the prior art requires a pulse width <30 fs, which has not yet been realized by a relatively narrow-band Yb-doped laser amplifier. For existing high-power Yb-doped lasers, nonlinear compression must first be performed through hollow-core fibers ...

AI Technical Summary

Problems solved by technology

Due to the high difficulty of nonlinear compression coupling through hollow fiber and low output efficiency, the power capacity of photonic crystal fiber is limited. At the same time, the nonlinear compression based on hollow fiber and photonic crystal fiber needs to cooperate with expensive chirped mirrors for subsequent pulse compression.

This greatly increases the complexity of the mid-infrared femtosecond laser, limits the pulse energy and average power, and increases the cost

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