We demonstrate the post-compression of the GW-level femtosecond pulse in a solid-state multi-pass cell (MPC) by the pre-chirp management method. When the laser pulse is positively pre-chirped, the 200 μJ 170 fs input pulse is compressed to 163 μJ 44 fs at the output, corresponding to a transmission of 81% and a pulse shortening factor of 3.86. When the laser pulse is negatively pre-chirped, the spectral evolution, as the pulse propagates in the MPC, is characterized and, eventually, the pulse duration is compressed to 51 fs, corresponding to a pulse shortening factor of 3.3. After the driving laser goes through the pre-chirp managed MPC device, the power stability and beam quality are almost preserved. The experimental results offer a viable path toward the post-compression of high-peak-power laser pulses.

Temporal contrast directly affects the interaction between ultraintense and ultrashort pulse lasers with matter. Seed laser sources with broad bandwidth and high temporal contrast are significant for overall temporal contrast enhancement. The technique of cascaded nonlinear processes with optical parametric amplification and second-harmonic generation is demonstrated for high temporal contrast seed source generation. Within 40 ps before the main pulse, the temporal contrast reaches over 1011. The pulse energy and duration of the high-contrast pulse are 112 μJ and 70 fs, respectively. Considering its high beam quality and stability, this laser source can serve as a high-quality seed for Nd:glass-based ultraintense and ultrashort pulse laser facilities.

We demonstrate the simultaneous temporal contrast improvement and pulse compression of a Yb-doped femtosecond laser via nonlinear elliptical polarization rotation in a solid state multi-pass cell. The temporal contrast is improved to 109, while the pulse is shortened from 181 to 36 fs, corresponding to a compression factor of 5. The output beam features excellent beam quality with M 2 values of 1.18 × 1.16. The total efficiency of the contrast enhancement system exceeds 50%. This technique will have wide applications in high temporal contrast ultra-intense femtosecond lasers.

We demonstrate a diode-pumped femtosecond Yb:CaGdAlO4 (Yb:CALGO) laser with a semiconductor saturable absorber mirror (SESAM) for stable mode-locking operation. A perfect beam profile is measured under 10 W output power with $M_{x}^{2}$ = 1.017 and $M_{y}^{2}$ = 1.016 in the horizontal and vertical directions, respectively. At the repetition rate of 71.66 MHz, the optical pulse duration is 247 fs and the pulse energy is 140 nJ at the central wavelength of 1041 nm, corresponding to a peak power of 0.56 MW. In addition, we also generate continuous wave (CW) power of more than 15 W with TEM00 mode, corresponding to an optical-to-optical efficiency of 44.1%.