Actively And Passively Q-switched 1.617 ?m Er:YAG Laser Resonantly Pumped By Diode

The 1.617?m high-energy Q-switched pulse laser located in the“eye-safe”waveband has wide application and development prospects in the fields of laser ranging,remote sensing,laser radar and mid-infrared laser generation.At present,resonant pumping Er:YAG crystal by a semiconductor laser diode?LD?is one of the most effective way to efficiently obtain a 1.617?m laser.In this paper,the experimental methods of obtaining 1.617?m pulsed laser are studied based on active and passive Q-switching.By using 1532 nm LD as the resonant pump source,1.617?m pulsed lasers with high stability,high efficiency,high energy and narrow pulse width are obtained by active and passive Q-switching,respectively.The main contents include:?1?Using the 1532 nm LD as the resonant pump source,the 1.617?m pulsed Er:YAG laser is achieved based on the voltage-on-type rubidium titanyl phosphate?RTP?electro-optic Q-switching.Experimentally,the variation of the output pulse width of the Er:YAG Q-switched laser with the incident pump power at 100 Hz,500Hz,1 kHz and 2 kHz pulse repetition frequency is investigated.As the pump power increases,the pulse width of the laser generally decrease,and the narrowest pulse width is about 70 ns.Accordingly,the output pulse energy increases with the increase of pump power,and the maximum pulse energy is about 4.7 mJ.?2?Using the 1532 nm LD as the resonant pump source,the 1.617?m pulsed Er:YAG laser is achieved based on Cr²⁺:ZnSe crystal passive Q-switching.Firstly,the saturable absorption parameters of Cr²⁺:ZnSe are measured.The results show that the Cr²⁺:ZnSe crystal has excellent saturable absorption at 1.617?m.Then,the output characteristics of the laser with the output coupler transmittance of 10%and 20%are studied.When the output coupler transmittance is 20%,the Q-switched Er:YAG laser operated at 1.617?m.The Q-switched Er:YAG yields the maximum output pulse repetition frequency,the maximum pulse energy,and the minimum pulse width of1.656 kHz,0.3 mJ,and 330 ns,respectively.The timing jitter of the pulse is less than2%,which indicates that the laser operated in a very stable Q-switching state.