Q-switching Of Character And Analysis The Reverse Saturable Characteristic Of Organic Material

Diode-pumped all-solid-state lasers(DPSL) has lots of advantages,such as compact structure, high stability and optical-optical conversion efficiency. It is widely used in national defence, photoelectron industry, communication, medical treatment and sanitation. Laser crystal is the core of diode-pumped all-solid-state lasers, which decide the output characteristics of laser. The characters of Cr4+:YAG crystal on Q-switching are introducing. At last we analysis the reverse saturable. The content of this dissertation is listed as below:1.The history and progress of diode-pumped solid-state lasers are reviewed; and the characters of the diode-end-pumped solid-state laser are presented; then the dissertation presents the crystals of fitting diode-end-pumped. To develop a kind of optieal-limited laser protection materials and based on the analysis of the prineiple and technology of laser protection and laser protection materials.2. The characters of Cr4+:YAG crystal on Q-switching are introducing, Based on the equation of velocity, a theoretical analysis and numerical simulating method considering the characteristic of the saturated absorber, which study on the output property of Nd:YVO4 and Nd:GdVO4 crystal.We discuss the influence on the output power if the thermal lenses is taken into account. The experimental results show that ,Output power with pump power is similar to a linear ,pulse width with the increase in pump power decreases along with the repetition rate of the pump power increases, both on the role of the increase in peak power remained unchanged, so peak power is also similar with the pump power increases linearly, when the pump power is 7.97W, the output laser power is 0.709W, pulse width is 48ns, the repetition rate is 38kHz and the peak power is 38.87kW, which is consistent with the theoretical value.3. A theoretical rate-equation simulates the instantaneous relationship of particles on each energy level, considering about the influence of laser pulse width at particles about absorption .If the pulse width is assimilated to the lifetimes of energy level. Dynamic result of reverse saturable absorption indicates that particles distribute at the energy level. Transmittance for various values of intensity is simulated with parameter of C60 and HITCI when excited state absorption cross section is larger than ground state's. The larger absorption cross section upper energy level can restrain saturation absorption as the intensity increased, then enhance performance of optical limiting. Therefore, nonlinear reverse saturable absorption is explained theoretically.