Fig. 1. Layout of the TDFL-pumped Ho:YAG oscillator and amplifier system. (DM1, HT at 0.79 μm and HR at 1.91 μm; DM2, HT at 1.91 μm and HR at 2.09 μm; DM3, HT at p-polarized 2.09 μm and HR at 1.91 μm.)

Fig. 2. (Color online) Typical output spectra of TDFL1. (a) The pump current was set at 1.40, 1.60, and 1.90 A, respectively; (b) the pump current was set at 1.45, 1.65, and 1.98 A, respectively.

Fig. 3. (Color online) CW output characteristics of polarized the Ho:YAG oscillator. (a) The pump absorption efficiency of the Ho:YAG crystal, the CW output power, and the transmittance of DM3; (b) the beam quality measurement and spectrum of the output laser.

Fig. 4. (Color online) Pulsed output characteristics of the polarized Ho:YAG oscillator. (a) Pulse energy and pulse duration versus PRF with pump power of 51.6 W; (b) the pulse profiles at eight different PRFs.

Fig. 5. (Color online) Output characteristics of the polarized Ho:YAG amplifier. (a) Amplified output CW power versus pump power from TDFL2; (b) amplifier pulse energy and pulse duration versus PRF with TDFL1 power of 51.6 W and TDFL2 power of 37 W.

Fig. 6. Layout of the TDFL-pumped Ho:YAG oscillator and amplifier system. (DM4, T≈90% at 3–5 μm and HR at p-polarized 2.09 μm).

Fig. 7. (Color online) (a) Comparison of typical pump pulse profile and parametric pulse profile; (b) the beam quality measurement of parametric light.

Fig. 8. (Color online) (a) Total parametric output average power versus incident pump average power at a PRF of 3 kHz; (b) the beam quality measurements at three typical parametric pulse energies.