Disc Laser Output Characteristics And Ase

The diode-pumped solid-state disc-laser is topics of current interest, which plays an important role in the study of high-power lasers and is of great potential and broad perspective in application. Starting from the rate equation of disc laser, In this dissertation, the research results on dynamical characteristics of high-power solid-state multi-disc laser resonators, discrepancies of the thermal focal length of discs and the ASE in high-power laser resonators are presented.Recent advances of diode-pumped disc-laser are reviewed .The power-scalable experiment schemes and related results are analyzed. Some problems for practical application are discussed too. The models of one-disc lasers are introduced in two different mediums. The general calculating methods of ASE for laser amplifiers are introduced. Based on the above theory and methods, the main works of this thesis are listed as follows:By using the concept of equivalent resonators, dynamical characteristics of high-power solid-state multi-disc laser resonators are analyzed. The general expressions for g* -parameters (equivalent g-parameters) and equivalent resonator length of multi-disc resonators are derived which permit us to obtain the dynamical characteristic curve and critical refractive powers on the g* -parameter diagram for multi-disc resonators and to illustrate their dynamical characteristics with numerical examples. The dynamic characteristics of multi-disc symmetric plane-plane resonators are analyzed in detail. It is shown that for two types of multi-disc symmetric plane-plane resonators, the characteristic curve on the g -parameter diagram is a straight line passing through the origin. If there are small discrepancies of the thermal focal length of discs, the characteristic curve is no longer a straight line. However, by a suitable adjustment of the distances between the mirrors and discs, the curve becomes again a straight line. Therefore, the discrepancies of the thermal focal length can be compensated in such a way, and the relevant mathematical formulas are also given.Introducing the concept of la (the average transporting distance of beams in the disc laser) and modifying the rate equation, a model to predict the outputpower and optical efficiency is presented, in which the ASE (Amplified Spontaneous Emission) is considered. The output power and optical efficiency of different resonator parameters and pump power have been analyzed with numerical calculation. It is shown that, because of the large diameter disc and low reflectivity output mirror of high power disc lasers, its ASE is more obvious than that of low power lasers. Based on this work we have given detailed analyses of the influences of different resonator factors on ASE and the measures to decrease ASE are suggested. The results obtained in this paper are useful for the design of high-power solid-state lasers resonators.