| Autor: |
Helena Jelínková, Karel Nejezchleb, Jan Šulc, Karel Veselský |
| Rok vydání: |
2020 |
| Předmět: |
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| Zdroj: |
Solid State Lasers XXIX: Technology and Devices. |
| Popis: |
In this research we focused on experimental measurement and modeling of the thermal lens in the active medium of diode pumped solid-state lasers at low temperature. The numerical model included the temperature and stress distribution leading to change of the index of refraction distribution and bulging of the faces of active medium. Evaluation of the influence of the main thermomechanical and thermo-optical properties of the active medium is presented. The important dependence of these parameters on the temperature and the doping concentration which leads to nonlinear equations is emphasized. The numerical model is compared with commonly used simple analytical solution. The results of the simulations are confronted with the experimental results of the measurement of refractive power of thermal lens formed in diode pumped Yb:LuAG and Yb:YAG lasers. In the experiments the crystals with different doping concentration were longitudinally pumped by fiber coupled CW laser diode at 0.930 μm with the focal point 0.2 mm in diameter. The 38 mm long semi-hemispherical laser resonator was used. The output laser oscillation wavelength was 1.03 μm. The refractive power of thermal lens was estimated indirectly by measuring of change in the position of focused laser beam focal point. The measurement was performed for constant absorbed power of 10 W in temperature range from 80 up to 240 K. The experiments showed strong dependence of refractive power on doping concentration at higher temperatures and importance of temperature and doping concentration dependence of material parameters for simulation which is often neglected. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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