Propagation of light pulses in a chirped-pulse-amplification laser

TLDR

The study investigates the propagation and compression of broadband pulses in a CPA laser, including the effect of gain saturation. The analysis models pulse evolution by treating amplifier gain as a function of instantaneous frequency, accounting for gain narrowing, self‑phase‑modulation, and gain saturation. Experimental results from an Nd:glass CPA laser system agree with theory, and both experiment and theory show that self‑phase‑modulation significantly shapes the compressed pulse even at low cumulative B‑integral values (B≤2).

Abstract

The propagation and compression of a broadband pulse in a chirped-pulse-amplification (CPA) laser is studied. Gain narrowing and self-phase-modulation (SPM) are the main mechanisms that modulate the final compressed pulse temporally and spectrally. The effect of gain saturation is also investigated. Due to the large chirp of this type of laser pulse, the power gain of the amplifier can be treated as a function of instantaneous frequency to simplify the analysis. Experimental results from an Nd:glass CPA laser system are in good agreement with the theory. Both experimental and theoretical results show that SPM can play an important role in determining the final shape of the compressed pulse, even at relatively low values of the cumulative B-integral, B<or=2.<<ETX>>