High-power Lda-pumped Solid-state Laser Amplifier Research

Diode Pumped Solid-State Laser(DPSSL) leads the development of the solid-state laser, which is the only kind of laser can satisfy the needs of IFE with about 10Hz repetition frequency, MJ grade energy and tens ns per pulse, 10% conversion efficiency, high reliability and low cost. High power diode array, pump coupling technology and thermal management are the key technology cells of DPSSL. Among them, the high power diode array is the core parts; whether pump coupling design that reasonable efficiently, is influencing the increasing benefit ability and the uniformity of increasing benefit of the system; the thermal effect is the key obstacle that DPSSL heads to high-efficiency and high light beam quality with high repeated frequency operation.From the diode laser array-pumped solid-state energy transfer mechanism, a systematic theoretical study and three-dimensional solid modeling simulation on the optical parameter of diode array, the alignment method of stacks, coupling efficiency , the energy deposition of laser medium, the laser amplifier, the thermal management etc. And through the establishment of a 24kW high-power diode array-pumped neodymium glass laser amplifier experiment carried out research and checked the procedures, made a series of important results, including:1) The establishment of a Monte Carlo method used to describe the light of diode array (bar) light-emitting solid model with a divergence angle of shaft speed, transmission power, optical properties such as light-emitting area, on the basis of the diode bar Model along the fast axis direction is stacked diode array model, m×n array of rank shall be pumped by the diode array model;2) Based on three-dimensional ray-tracing model of the pump coupling and large-caliber high-power diode array end-pumped solid-state laser amplifier coupling a new way - laser diode array stack arranged to be spherical, planar array of laser axis rotation speed of the turn with 90°(rotating windmill order), hollow silver-plated stainless steel (or aluminum) duct coupled to the coupling of simulation methods to study the gain medium and the coupling of the energy deposition efficiency of coupling the output field uniformity and transmission, etc., within the gain medium in which energy deposition could be used as the gain performance analysis and thermal management within the initial heat distribution, which can be used as an analysis of optimization of the pump coupling arguments;3) We studied the DPSSL thermal effects, based on ray-tracing inside the heat source distribution and the finite element method to establish the thermal management of three-dimensional solid model and simulation of the gain medium in the direct phase change materials with water-cooled heat sinks under the three-dimensional cooling temperature distribution, as well as clamping the gain medium on the medium thermal stress distribution and deformation distribution, starting from the thermal management of the optimized design DPSSL;4) We established a 24kW high-power diode array pumped Nd glass laser amplifier system, carried out DPSSL pump coupling, thermal management and gain performance of the experimental research and simulation of the calibration procedure. Experimental studies have shown that the pump coupling efficiency was 71.7%, the pump operates in a 5mm output coupling transmission efficiency of 85%, maximum one-way for the small-signal gain of 1.29 times the maximum small-signal gain coefficient of 0.42cm^-1, heat steady-state wave-front distortion when PV value is 0.92λ, wavefront aberration RMS value of 0.1λ,. We established the use of simulation procedures, the theoretical calculation of coupling efficiency was 90%; pump coupling 5mm output field in the transmission efficiency of 89%; simulation achieved thermally-induced wavefront aberration, in line with theexperimental gain curve.