| The eye-safe 2?um laser has a wide range of emerging scientific and technological applications in the fields of ranging,laser weapons,medical surgery,material processing and atmospheric sensing because of its location in the strong water absorption band and in the atmospheric output window,and 2 ?m lasers are also available.As a pump source for mid-infrared(3-5 ?m)OPOs.In view of the wide application of 2 um band lasers,the human eye safety 2 ?m band solid-state laser has been favored by many researchers since its appearance.The use of semiconductor laser or fiber laser pumping Tm3+,Ho3+,Tm3+ and Ho3+ co-doped laser materials to generate laser lasing is still the most direct and direct technical means for obtaining 2 um band lasers.In this thesis,the characteristics of Tm:LuAG,Tm:LuYO3 Tm:YSO and Tm:CYA crystals and ceramic materials doped with Tm3+ laser materials in the human eye are 2?m wavelength continuous wave laser,passive Q-switched laser and passive Q-switched laser Analysis.The research work of this thesis mainly includes the following three main parts:(1)Firstly,Tm:LuAG,Tm:LuYO3 and Tm:YSO three continuous wave laser experiments with Tm3+ laser materials are realized.For Tm:LuAG ceramic crystals,continuous wave lasers with laser wavelengths of 2016 nm were realized using output mirrors with transmittances of 10.3%and 8.1%respectively.The corresponding maximum output power and oblique efficiency were 2.41 W,35%And 2.64W,35.6%respectively.For the new Tm:LuYO3 ceramic crystal continuous wave experiment,using output mirrors with transmittances of 6.6%and 1.8%respectively,the laser wavelengths are all at 2050 nm,the maximum output power is 1.19 W and 1.55 W,respectively.and the oblique efficiencies are about 17.8%and 19.9%.For the Tm:YSO continuous wave laser experiment,four output mirrors with different transmittances are used,and the corresponding laser wavelength,maximum output power,oblique efficiency are(1976.0,2.64 W,28.3%),(1969.8,3.23 W,34.3%),(1972.9,2.37 W,25.6%)and(2044.6 nm,1.36 W,17.5%).(2)Then,the Cr2+:ZnSe crystal is inserted into the resonant cavity as a saturable absorber,thereby realizing a passive Q-switched laser experiment in the 2 ?m band.The maximum average power,the shortest pulse width,the maximum pulse energy and the maximum peak power of the Tm:LuAG passively Q-switched laser operating at 2016 nm are(1.06 W,277 ns,81.4 ?J,288 w)respectively.For the Tm:LuYO3 ceramic passive Q-switched laser experiment.The single-wavelength Q-switched operation at 2047 nm has a maximum average power,a shortest pulse width,a maximum pulse energy,and a maximum peak power of(0.54 W,120.3 ns,20.5 ?J,and 170.6 w),respectively,and a double of 1957 and 2047 nm.The maximum average power,the shortest pulse width,the maximum pulse energy,and the maximum peak power corresponding to the wavelength Q-switching are 0.92 W,151.6 ns,30.2 ?J,199.1 W,respectively.The maximum average power,the shortest pulse width,the maximum pulse energy,and the maximum peak power of the Tm:YSO passively Q-switched lasers operating at 1944 nm and 2022 nm were 0.74 W,78.3 ns,71.8 ?J,917.5 W and 0.31 W,101.3 ns,50.8?J,501.6 W respectively.These results indicate that Tm:LuAG,Tm:LuYO3 and Tm:YSO ceramics and crystal lasers are promising laser sources in the human eye safety spectral region.(3)Finally,the Tm:CYA crystal Q-switched mode-locked laser was realized.Among them,the maximum output power of continuous wave of Tm:CYA crystal running at 1957.33 nm is 3.16W,and the corresponding oblique efficiency is 20.2%.When the saturable absorber Cr2+:ZnSe is inserted into the cavity,the maximum average output power of the Q-switched mode-locked laser operating at 1194.85 nm is 818 mW,and the maximum pulse repetition rate and pulse energy of the Q-switched envelope are 13.1 KHz and At 63.7 ?J,the interval between the mode-locked pulse sequences developed under a single Q-switched envelope is approximately 8.3 ns,the corresponding repetition rate is 121 MHz,and the mode-locked pulse width is approximately 951 ps. |
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