Analysis on preferential free running laser wavelength and performance modeling of Tm³⁺-doped YAP and YLF

The preferential free running laser wavelength at room temperature for different axes cuts of Tm³⁺-doped YAP and YLF is comparatively analyzed in this paper. The polarized gain spectrum of Tm:YAP and Tm:YLF with different product values of Tm³⁺-doped concentration and crystal length is theoretically calculated under various cavity output mirror transmissions. From the gain spectrum, it straightforwardly determines the preferential free running laser wavelength for a given light polarization. In addition, a rate equation model is further used to model and compare the laser output performance for both the free running and some common artificially selected oscillating wavelengths, including 1.99 and 1.94 μm of Tm:YAP, and 1.89, 1.91, and 1.94 μm of Tm:YLF, respectively. To achieve an expected laser oscillating wavelength with acceptable output performance, our analysis presented here is very beneficial for one to choose the most suitable axis cut of crystal.