| Tm:YAP mode-locked lasers have been able to output lasers near the 2mm band due to the unique energy level structure of Tm3+in the Tm:YAP laser crystal,and have received more and more attention in recent years.The laser near the 2mm band is located near the absorption peak of water molecules,which is also a relatively safe band for the human eye,and is in an atmospheric window with a relatively high transmittance,and has a characteristic spectrum of many important molecules.Compared with lasers of other wavelengths,2mm lasers are widely used in medical,remote sensing,optical communication,military and other fields due to their unique properties.In view of the important application and research value of the laser in the 2mm band,the main research content of the Tm:YAP mode-locked laser in this article includes the following aspects:1.Research on Tm:YAP laser crystals:Tm:YAP laser crystals are anisotropic crystals with different spectral characteristics in different tangential directions;Tm:YAP laser crystals thermal lens effect study,different pump powers The influence of the spot radius and other factors on the focal length of the crystal thermal lens is calculated numerically.2.Analysis of the mode locking principle of semiconductor saturable mirrors?SESAMs?and carbon nanotubes.In the study of the continuous Tm:YAP laser rate equation and the passive mode-locking rate equation based on SESAM,only the pulse energy in the resonant cavity is greater than the minimum pulse energy required for continuous mode-locking operation to achieve continuous mode-locked pulse output.The lasers of straight cavity and folded cavity are researched separately.The MATLAB software is combined with the matrix equation to simulate and analyze the stable region and the change of the laser spot radius in the cavity to optimize the design of the resonant cavity.3.The dispersion compensation problem of Tm:YAP laser crystal is studied.According to the refractive index equation of Tm:YAP laser crystal,the dispersion compensation is numerically calculated by MATLAB software,and the grating pair is optimized.In the band around 2mm,the dispersion of the Tm:YAP laser crystal becomes negative dispersion instead of the near infrared positive dispersion.For the dispersion compensation of the Tm:YAP laser crystal,we need to use a device that generates positive dispersion to perform dispersion compensation.4.The experimental study of Tm:YAP mode-locked laser,based on the transfer matrix,was simulated using MATLAB software.The stable region of the resonant cavity of Tm:YAP mode-locked laser under different pump powers,and the variation of the spot radius in the resonant cavity. |
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