Research progress of ultrashort pulse laser based on Yb:CaAlGdO₄ crystal

Ultrashort pulsed lasers with high peak and average power play a crucial role in various fields, including strong-field experiments, nonlinear frequency conversion, and laser-material interactions. The Yb:CaAlGdO₄ (Yb:CALGO) crystal stands out as a new-generation laser material, offering the broadest emission bandwidth and exceptional thermal conductivity, making it a prime candidate for generating high-power femtosecond pulses. An overview of the Yb:CALGO crystal is presented, followed by a review of ultrashort pulse oscillators and regenerative amplifiers based on Yb:CALGO developed both domestically and internationally and the key problems such as cavity structure design, crystal parameters, and pulse compression are analyzed. In the section on oscillators, two mode-locking techniques are discussed: semiconductor saturable absorber mirror mode-locking and Kerr-lens mode-locking. Finally, the research findings are summarized, and prospects for laser systems with higher power, greater energy, and shorter pulse durations are explored.