A Study Of The Dual-wavelength Alternating Output Laser Based On The Same EO Q-Switched Voltage

The dual-wavelength laser has a wide range of applications in laser communication,laser ranging,differential absorption radar and other fields.At present,the generation of dual-wavelength laser is mainly focused on the simultaneous output of two wavelengths.However,the two-wavelength laser cannot achieve the effect of separation in the time domain,which greatly limits the application of dual-wavelength laser in laser medicine,laser spectrum and other fields.At the same time,the dual-wavelength laser alternating output technology can be fully utilized in the field of laser fat melting.For example,the laser at 1064 nm band can be used to destroy adipose tissue in a larger range,while the laser at 1320 nm band can absorb the tissue near the action point.The alternating output laser of the two bands can produce higher fat decomposition efficiency in order to achieve the best liposuction effect.In addition,Nd:YAG crystal has the advantages of low threshold and high efficiency,and it is the preferred laser gain material for producing 1319 nm and 1064 nm bands.In this paper,the alternating output of 1319 nm and 1064 nm dual-wavelength pulse laser based on the same electro-optic(EO)Q-switched voltage is studied and discussed theoretically and experimentally.In terms of the theory: based on the four-level model of Nd:YAG gain medium,the principle and physicochemical properties of 1319 nm and 1064 nm laser output from Nd:YAG crystal are analyzed.At the same time,the voltage-increased and voltage-decreased modes in the resonant cavity based on the same EO Q-switched voltage are discussed respectively.According to the dual-wavelength EO Q-switched theory,the dual-wavelength alternating output rate equation under the same EO Q-switched voltage is established.The alternating output at 200 ?s interval phenomenon and output characteristic trend of dual-wavelength laser are simulated by Matlab simulation software in accordance with the calculation of 1319 nm and 1064 nm ?/4 voltage corresponding to RTP EO Q-switched crystal,the comparison of loss and gain in each resonant cavity and the alternating output time sequence relationship.In addition,through the focal length formula of the side-pumped thermal lens,the changing trend of the thermal lens focal length of the crystal under a certain total dissipative power is obtained.Finally,the stable region of 1319 nm straight cavity and 1064 nm folded cavity is simulated with ABCD matrix,which provides a theoretical basis for subsequent experiments.In terms of the experiment: based on the theory and experimental design,the experiments of 1319 nm and 1064 nm single-wavelength laser output and dual-wavelength alternating output based on the same EO Q-switched voltage are respectively verified.The1319 nm and 1064 nm dual-wavelength laser output at 200 ?s intervals is achieved at the repetition frequency and the same EO Q-switched voltage of 5 Hz and 1000 V,respectively.Its output characteristics are as follows: when the maximum pump current is90 A for 1319 nm and 70 A for 1064 nm,the single pulse energy and pulse width of 1319 nm is 42.37 m J and 15.88 ns,respectively,and the single pulse energy and pulse width of1064 nm is 43.60 m J and 14.58 ns,respectively.Within 30 minutes,the energy stability of the single pulse is 4.2 % and 3.6 % of 1319 nm and 1064 nm,respectively.Through the experimental results,it is proved that the dual-wavelength laser can be alternately Q-switched by the same Q-switched voltage to realize the alternating output of dual-wavelength laser.