Fig. 1. Femtosecond laser direct writing of Tm∶YAP waveguide. (a) Optical transmission micrograph of cladding waveguide fabricated in Tm∶YAP crystal; spatial 2D distributions of micro-photoluminescence (μ-PL) (b) intensity, (c) shift, and (d) bandwidth obtained from the cladding waveguide cross section, and the μ-PL analysis is conducted in the dashed frame in Fig. 1(a)

Fig. 2. Optical properties of Tm∶YAP cladding waveguide and NbSe₂ thin film. (a) Transmittance of fabricated Tm∶YAP cladding waveguide in different polarizations; (b) relative output laser power under optical pumping at different wavelengths; (c) linear absorption spectrum and (d) 2 μm I-scanning measurement result of NbSe₂ thin film

Fig. 3. Laser performance of Tm∶YAP Q-switched mode-locked waveguide. (a) Relationship between output laser power and pump power under TE and TM polarizations, the insets show the near-field modal profiles under two different polarizations; (b) wavelength tuning of laser emission under optical pumping with different polarizations (TE, 45°, and TM from left to right); (c) Q-switched envelope sequences, and the inset shows a single Q-switched envelope; (d) mode-locked trains; (e) RF spectrum