Research On Self Mode-locking Tm:YAP Solid State Laser Based On Kerr Lens Effects

Ultra-short pulses have the characteristics of high time resolution,high spatial resolution,high bandwidth and possibility of high intensity.Ultra-short pulse technology is an important means to study in the micro-world and explain the new ultra-fast process in disciplines such as physics,chemistry,biology,optoelectronics and laser spectroscopy.Self-mode locking is an important technique for obtaining ultra-short pulses.In this thesis,the self-mode-locking operation of two-mirror and five-mirror lasers is successfully realized by using the Kerr lens effect of Tm:YAP crystal.We use Mathematica to simulate the intracavity distribution of the spot radius,the relationship between the thermal focal length of the laser crystal and the intracavity optical power,the relationship between the intracavity spot radius and the thermal focal length of the laser crystal in the two-mirror and five-mirror cavities.Through the analysis of the simulation results,the position of the laser crystal in the self-mode-locked laser is confirmed,which ensures that the mode matching between the pump light and the intracavity light in the crystal can meet the requirements of the self-mode-locked laser during the experiment.On the basis of software simulation,two-mirror and five-mirror cavities are set up for experiment.By adjusting the resonator,the pump light and the intracavity light have a good mode matching,both two-mirror-cavity and five-mirror-cavity lasers have achieved self-mode-locked operation.The pulse width of the output laser is about 600 ps,the repetition frequency is about 468 MHz,the center wavelength of the laser spectrum is 1943 nm,the lasing efficiencies of the laser are 15.9% and 19.7% respectively with output mirrors of 4% and 6% transmittance in the two-mirror-cavity laser.The pulse width of the output laser is about 6 ns,the center wavelength of the laser spectrum is 1937 nm,the lasing efficiency of the laser is 10.1% with output mirror of 4% transmittance in the five-mirror-cavity laser.