Owing to the rapid development of new energy technologies such as lithium batteries, photovoltaics, and display semiconductors, higher requirements have been imposed for the average power, pulse energy, and pulse duration of lasers. Pulsed lasers, with average power levels in kilowatts and pulse energies in millijoules, have been researched and developed extensively. Currently, pulsed lasers are implemented via two different implementations: direct oscillator power amplification and main oscillator power amplification (MOPA). The former directly increases the power and energy of the laser oscillator, and as the power and energy increase continuously, an increase in the risk of intracavity damage limits the further power scaling of the laser. The latter rod- or slab-amplification technology affects the beam quality of the laser as the power increases. In this study, a laser system combining disk regeneration pre-amplification technology and disk multipass amplification technology is proposed, with the laser pulse output exhibiting a pulse duration of less than 6.8 ps, an average output power of 1102 W, an optical efficiency of 50.1%, a beam quality factor M² of less than 1.4, and a power stability of 1.29% obtained at a repetition rate of 1 MHz. Additionally, under a repetition rate of 100 kHz, the maximum output pulse energy is 8.23 mJ and the M² is less than 1.5.

In this study, MOPA technology based on the domestic 30 MHz fiber seed is adopted. The seed repetition rate is decreased to 1 MHz and the fiber seed is injected into the disk-regeneration gain module, which results in a laser output of 151 W. Subsequently, the fiber seed is injected into the disk multipass gain module for main amplification, and an average power output of 1102 W is realized. The output pulse duration is less than 6.8 ps, the optical efficiency is 50.1%, the M² is less than 1.4, and the power stability is 1.29%. The output power is 823 W and the maximum pulse energy is 8.23 mJ under a repetition rate of 100 kHz.

The kilowatt laser system obtains a picosecond pulsed laser with a power level of 151 W and a repetition rate of 1 MHz through regenerative pre-amplification. Additionally, it injects the fiber seed into the main amplifier for amplification. The disk crystal diameter used in the main amplifier is 19 mm, the radius of curvature is 50 m, the thickness is 100 μm, and the doped mass fraction is 10%; additionally, the disk crystal is water cooled at 25 °C. The pump source is a fiber-coupled semiconductor laser with a center wavelength of 969 nm and a maximum output power of 3000 W. The distance between the disk and mirror is approximately 0.5 m. The reflective mirrors of the amplifier are plane mirrors, and the laser is self-imaged through the disk crystal thermal lens to form a self-reproduction mode.

In this study, using a domestically produced disk gain module, a seed source, and a pump gain module, a picosecond pulse laser output with a M² better than 1.4, a maximum power of 1102 W, a pulse duration of 6.8 ps, and an optical-to-optical conversion efficiency of 50.1% is obtained at a repetition rate of 1 MHz. Meanwhile, a laser pulse output with M² better than 1.5, an average power of 823 W, and a maximum pulse energy of 8.23 mJ is obtained at a repetition rate of 100 kHz.