Radiation Cooling In Solid-state Lasers Dropped With Yb～(3+) And Pump Technology

Optical refrigeration in solid-state lasers, as a new concept, can reduce the heat generated in laser medium in a different approach. Radiation balanced lasers (RBL) are analyzed through numerical simulation in this thesis. In RBL, the heat generation in the gain medium is compensated by optical refrigeration. The main work of the thesis is as follows:1. Heat generation and thermal effects in solid-state lasers were summarized, along with the development of optical refrigeration which uses anti-Stokes fluorescence to realize cooling, and then the basic theories on RBL were represented. Yb:KGW was proposed as the candidate gain medium for RBL and wavelength condition must be satisfied in RBL;2. The pump and laser intensity distributions are plotted in RBL of Yb:KGW under both the single-pass amplifier and resonator cavity conditions;3. Side-pumped solid-state laser with low thermal loading was simulated numerically by ray-trace method, and the pump power distribution is calculated, under different conditions. Using the software ANSYS, we calculate the temperature distribution in medium. At last, the factors which affect the distribution of absorbed power and temperature are analyzed.The conclusions of this paper have some instructional meanings to design the pump source in radiation-balanced lasers and settle the contradictory between increasing the output power and keeping beam quality.