High-energy broadband Nd: Glass regenerative amplifier with coated birefringent filter for the high-power laser facilities

The regenerative amplifier is an important component of the high-power laser facility. A high-energy broadband Nd: glass regenerative amplifier with an energy of 34.1 mJ and a bandwidth of 4.3 nm was demonstrated using an intra-cavity specially coated birefringent filter (CBRF). This letter proposes a design scheme for a CBRF that can control the flat-top area of gain spectrum of the regenerative amplifier, which has been studied theoretically and experimentally. The transmittance of the specially coated BRF was tested in this experiment. The amplifier output spectrum had a flexible control ability and long-term stability. It can be applied to support high-energy broadband amplification in inertial confinement fusion (ICF) facilities, and can also be extended to other broadband amplification system to support high-energy picosecond petawatt laser facilities.