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Study On Solid-state Laser Crystal Thermal Effect LD Pumped

Posted on:2015-02-27Degree:MasterType:Thesis
Country:ChinaCandidate:L F QiFull Text:PDF
GTID:2268330425495979Subject:Optics
Abstract/Summary:PDF Full Text Request
High power diode pumping all-solid-state lasers have recently attracted much moreinterest for their unique merits, such as long lifetime, compact structure, high stabilityand optical–optical conversion efficiency,etc. It employs diode laser as the pumpsource instead of conventional Helium or Xenon flashlamp, leading to a significantimprovement of efficiency, reliability and beam quality, and thus called the revolutionof the laser history. With the development of high power diode lasers, high powerDPSSL has become one of the main objectives of current research and developmentactivities within the laser community. Research of DPSSL has mainly concentrated onscaling of output power, while remaining of a high spatial beam quality. The mainproblem hindering scaling of diode-pumped solid-state lasers is heat deposition withinthe laser medium. Laser crystal is the core of diode-pumped all-solid-state lasers,which decide the output characteristics of laser. In recent years, in endeavoring to obtainhigher output powers from continuous-wave end-pumped solid-state lasers, one mustconsider thermal effects that will impact optical performance.The thermal effect of Nd:YVO4crystal rods induced by laser diode-pumped is alsoanalyzed theoretically in this paper, the more rational boundary conditions areestablished considering the distribution of laser beam in the crystal and the heatconvection between the side surface of the crystal and the coolant, as a result, the moreactual temperature field in the crystal is obtained, and simultaneously the influences ofcrystal radius and pimp power on thermal effect are calculated.The thermal effect of Nd:YAG crystal rods induced by laser diode-pumped is alsoanalyzed theoretically in this paper, the more rational boundary conditions areestablished considering the heat convection between the side surface of the crystal andthe coolant as well as the convective heat-transfer about the pumped surface, as a result,the more actual temperature field in the crystal is obtained, and simultaneously theinfluences of crystal radius and pimp power on thermal effect are calculated.The contents can be outlined as follows:1. Reviewed the history and progress of diode-pumped solid-state lasers; and analysed the characters of the diode-end-pumped solid-state laser, such as incentivemode, the way of pumping, the laser medium structure, the solid laser crystal materialsof LD-pumped.2. The cause of engendering and the disadvantage of laser crystal as well as themethed of reducing thermal effects was presented. On the basis of thermal conductivity,the equation of square and round laser crystal was established. We explain the theoryof focal length.3. The thermal effect of Nd:YVO4crystal rods induced by laser diode-pumped isalso analyzed theoretically in this paper, the more rational boundary conditions areestablished considering the distribution of laser beam in the crystal and the heatconvection between the side surface of the crystal and the coolant, as a result, the moreactual temperature field in the crystal is obtained, and simultaneously the influences ofcrystal radius and pimp power on thermal effect are calculated. The results show that thetemperature in the center and on the side surface of the crystal increases when theconvective heat-transfer about the side surface is considered. As increasing the pumppower and crystal radius, the temperature of the crystal increases, considering theconvective heat-transfer about the side surface, the temperature different is wider.4. The thermal conduct model of rectangular laser crystal was established,Considering the heat convection between the side surface of the crystal with the coolwater as well as the convective heat-transfer about the pumped surface, the morerational boundary conditions were established. Using finite element difference methodand Poisson equation, temperature field in the crystal is obtained. The results show theconvective heat-transfer about the pumped surface and the side surface of the crystalwould lead to more actual temperature field, the focal length is more coincide to theexperiment.
Keywords/Search Tags:Laser diode pumped all-solid=state lasers, thermal effect, anisotropycrystal, the same-sex, focal length
PDF Full Text Request
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