In this work, we evaluated the feasibility of sapphire conductive cooling for short-pulse Ti:Sapphire (Ti:sa) laser amplifiers which suffers from thermal issues under high-repetition-rate and high-energy operation. Numerical heat transfer simulations of 100-TW class sapphire face-cooled Ti:sa gain modules operated around 300 W average powers are presented. The distributions of temperature, stress, strain, and birefringence in liquid cooled sapphire/Ti:sa/sapphire assembly are calculated by a finite element analysis. Based on these data, the thermal induced wave front distortions and depolarization are investigated for different repetition rates. We determine that sapphire face cooling concept holds a promise of achieving higher energies and repetition-rates in Ti:Sa amplifiers.
As the development of the laser-driven technology, the next generation of laser-driven device sets higher requirement for the repetition frequency. The higher repetition gives rise to thermal deposition, which induces thermo-optical effect, elasto-optical effect and bulk displacement. The thermal efficient management is an important approach to dissolve the thermal deposition. The quasi uniform distribution of heat medium is realized by helium cooling Nd:glass slab and the control of edge temperature. In the case, wavefront distortion and depolarization losses is obtained in experiment. Results said that both of them are improved greatly. At the same time, the distribution of temperature, stress and strain and stress birefringence in Nd:glass are analyzed by using finite element numerical simulation method. And the calculation results show that the wavefront distortion and depolarization losses match with the experimental results very well.
Diode-pumped solid state laser system based on cryogenic Yb:YAG active-mirror scheme are presented with recent energy output. With improved optical design, 6.05J/1Hz pulse energy is achieved and a conceptual design with 30J output energy is theoretical simulated. The doubling efficiency of YCa<sup>4</sup>O (BO<sup>3</sup>)(YCOB) crystal is also discussed in this paper.