Influences Of DPL Thermal Effect On Resonant Cayity Stability

In this paper, end-pumped mode with fundamental mode Gaussian beam is used.The paper mainly deals with calculation of temperature distribution in the laser crystal,thermal lens focal length and thickness, the maximum length of the resonator when theresonator is stable. The effect of the pumped power, doping concentration, pumpedbeam radius on the crystal temperature distribution is analysied. The article comparestwo mode, one is only considering the radial heat dissipation and the other isconsidering the radial heat dissipation and axial heat dissipation.The variation of thermallens focal length, thermal lens thickness, thermal lens position with pump power isdiscussed when there are two segment of the gain medium, three segment of the gainmedium,four segment of the gain medium,In this part, the laser crystal is divided intomany small segments, the thermal lens in each segment can be equivalent to the ideallens,the group of ideal lens is equivalent to an actual thick lens according to the theoryof lens combination.Also The variation of the maximum resonantor length when theresonantor is stable with radias and pumped power of the pumed beam is discussed inthis paper.In this part the situation of two segment of the gain medium, three segment ofthe gain medium,four segment of the gain medium is analysied, In this part,the length ofthe resonantor is set as variable, using transmission matrix and the theory of resonatorstability, the relationship of the resonantor length and the resonantor stability isdiscussed when the pump radius, pump power is changed.This paper studies the relationship of laser crystal temperature gradient andpumping source, cooling condition, especially dielectric crystal length, using the thinlens combination method and the equivalent thick thermal lens method. This paperpresents equivalent thick lens of the thermal lens, the method to define thick lens andcorresponding parameters. Through analysis and digital simulation ways we get usefulconclusion: effect of heat on the resonator stability depends not only on the thermal lensequivalent focal length, but also depends on the length of absorbing medium.