Study On Power Balance Of Dual Frequency Laser Based On Thermal Effect Of Neodymium-doped Medium

Microchip dual-frequency lasers?DFLs?are of great interests due to their potential applications in radio frequency?RF?metrology,holographic interferometer and doppler lidar.Nd³⁺doped laser materials,which are appreciated for their large emission cross sections?ECSs?and broadband ground-state absorption cross section spectra,are the ideal gain media for the microchip DFLs.In this paper,based on the dual-frequency laser output,the dual-frequency laser with Nd:GdVO₄ and Nd:YVO₄ integrated resonators was built to study the thermal effects of Nd:GdVO₄and Nd:YVO₄ dual-details as follows:?1?Based on the dual longitudinal mode output of the laser,the influence of thermal effect on the crystal of the laser medium is studied.The formula of the wavelength shift rate of the dual-frequency microdata laser is deduced and proved.It is proved that as the temperature increases,the central wavelength of the output laser of the microchip laser changes linearly with temperature.?2?The temperature characteristics of the emission spectra of Nd:GdVO₄ and Nd:YVO₄crystals were experimentally investigated.According to the corresponding relationship between the emission cross-section spectrum and laser wavelength,the influence of temperature on the output spectra of Nd:GdVO₄ and Nd:YVO₄ dual-frequency laser was further studied.The experimental results show that the emission spectrum of Nd:GdVO₄ and Nd:YVO₄ crystal shifts red-shifted with the rise of central wavelength and the peak of emission cross section decreases,and both of them have a quasi-linear relationship with the temperature in the studied temperature range.The wavelength of the microchip dual-frequency laser also shows a linear redshift with increasing temperature,but the two-frequency speration remains unchanged.The power balance of the dual-frequency laser components changes under the common redshift of the crystal emission cross-section spectrum and the laser spectrum.The output power balance of Nd:GdVO₄dual-frequency laser is less affected by temperature.And its dual-frequency laser power is more ideal.?3?Based on the FL formula,the model of power balance mechanism of microchip laser is established and elaborated,focusing on the relationship between pump power and heat sink temperature at power balance.Experimental results show that the laser diode laser power constant,Nd:GdVO₄ and Nd:YVO₄ dual-frequency laser chip laser medium crystal temperature is constant.?4?Based on the power balance mechanism of dual-frequency microchip laser,the relationship between pump power and heat sink temperature is further studied.The experimental results show that the power of the three dual-frequency lasers is adjusted when the pumping power is increased.The mode-hop of Nd:GdVO₄ dual-frequency lasers does not occur,the power product increases steadily,the center wavelength change rate is small,and the stability is good.And Nd:GdVO₄ laser is the ideal power tunable dual-frequency laser.