| The Nd3+ has abundant transition in the near infrared band.By 808 nm pump,it can realize the infrared band laser with a variety of wavelengths,such as 0.9,1.06,1.1,1.3 and 1.4 μm,etc.These near-infrared lasers have been widely used in medical,industrial,optical communications,defense,military and other fields,which has brought great convenience to the world.Ion neodymium laser material variety,in addition to the traditional Nd:YAG single crystal materials,study of mixed crystal materials and laser showed vigorous development trend,many mixed crystal materials were developed in recent years.Nd:LuYAG crystal is the most important representatives of mixed crystal materials.Nd:LuYAG mixed crystals have the same excellent thermal optical and mechanical properties as Nd:YAG single crystal,such as strong absorption and emission spectra,as well as obvious multi-peak structure,which is beneficial to obtain high power output and multiple wavelength laser.Hybrid crystals tend to have wider absorption and emission spectra than monocrystalline crystals,so they are expected to obtain shorter laser pulses in Nd:LuYAG mixed crystals.In this paper,Nd:LuYAG mixed crystal was used as the laser gain medium,808 nm LD laser as pump source,constructed a typical linear double mirror resonator.By optimizing the operation,we obtained the continuous laser of Nd:LuYAG mixed crystals of 0.9 and 1.4 μm.Under the free running mode,single wavelength of 946 nm and multi-wavelength of 1442、1432 and 1415.7 nm were obtained,the corresponding maximum output laser power,slope efficiency and optical-to-optical efficiency were(5.64 W,52.5%,42.2%)and(1.71 W,17.1%,13.3%).When the glass plate is inserted into the laser cavity,we obtained dual-wavelength output of 939 and 946 nm laser and the single wavelength laser oouput of 939,and the single wavelength laser oouput of 1442、1432 and 1415.7 nm,respectively,the corresponding maximum output laser power and slope efficiency were(3.61 W,34.8%),(2.0 W,26.4%),(1.26 W,13%),(0.365W,4.2%)and(1.1 W,19.3%).Using the transmittance of 95%Cr4+:YAG crystal as the saturable absorber,we achieved 946 nm wavelength Nd:LuYAG mixed crystal Q-switching pulse laser output,the corresponding maximum average output power,narrowest pulse width,.maximum single pulse energy and maximum pulse peak power were 0.68 W,8.4 ns,12.3 kHz,55.3 μJ and 6.15 kW.By using the transmittance of 95%V3+:YAG crystal as the saturable absorber,we also achieved 946 nm wavelength Nd:LuYAG mixed crystal Q-switching pulse.laser output,the corresponding pulse laser parameter values were 0.43 W,0.13 mu s,23.8 kHz,18.1 μJ and 139.2 W.At the same time,we also study the theoretical research.First,we established the rate equation by introducing the principle of Q-switch,then analyzed the process of the passive-Q-switched of saturable absorber in detail.We also simulated the Q-switch laser output characteristic curve and calculated the pulse width and repetition frequency under different pump power numerically.Secondly,the thermal effect is the main limiting factors restricting high power laser,so the paper also analyzes the Nd:LuYAG the thermal lens effect of mixed crystal finally,using thermal distribution model,the Nd:LuYAG carried out simulation on the heating effect of the mixed crystal. |
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