Research On 1.13 μm Diode-pumped Ho:YAG Laser

As an important greenhouse gas,N₂O has drawn more and more attention from researchers.For the application of differential absorption detection of coherent light source with N₂O,we conducted a research on a tunable single-longitudinal-mode Ho:YAG laser pumped by a 1.13μm diode laser.The main contents and achievements of this thesis are as follows:1.Firstly,we investigated the influence of N₂O gas on global climate change,elaborated the research background and significance of this paper.Secondly,we compared the different pumping methods of holmium-doped laser,and we found that it is more convenient to achieve a compact Ho:YAG laser when using 1.13μm diode laser as pump source.Thirdly,we summarized the research progress of 2μm single-frequency laser at home and abroad.2.We used the quasi-three-level rate equation theory to simulate and analyze the output characteristics of Ho:YAG laser pumped by a 1.13μm diode laser.Using the model of end-pumped solid laser,we analyzed the thermal effect of Ho:YAG laser.The temperature distribution in Ho:YAG crystal and the relationship between the pump power and thermal lensing effect were simulated.The thermal lensing effect on the stability of the resonator was also discussed.3.We achieved the continuous Ho:YAG laser pumped by a 1.13μm diode laser.We studied the impact of different parameters on the Ho:YAG laser such as the working temperature of LD,radius curvature of input mirror,output coupler and length of resonator.By optimizing the parameters of Ho:YAG laser,with the output coupler of 2%,the maximum output power of the Ho:YAG laser is 376.5 m W,corresponding to a slope efficiency of 17.4%,and the central wavelength of the laser is 2129.6 nm.4.With two intracavity F-P etalons,we achieved a tunable single-longitudinal-mode Ho:YAG laser pumped by 1.13μm diode laser.With the output coupler of 2%,the maximum single-longitudinal-mode output power is 102 m W at 2129.6 nm.The wavelength is tuned from 2119.7-2131.5 nm,which is consistent overlaps with the absorption spectrum of N₂O.The power fluctuation of the SLM at 2129.6 nm was measured to be less than 1.2%（RMS）over a period of 30 minutes.The output beam is close to the fundamental transverse electromagnetic(TEM₀₀)mode with M² value of 1.29in the X-direction and 1.28 in the Y-direction.The tunable single-longitudinal-mode Ho:YAG laser presented in this paper has potential applications in the study of N₂O differential absorption detection.