Fig. 1. Absorption spectrum of Pr–Nd glass. Resonant wavelength is 807 nm, whose absorption rate is 1.311. Nonresonant wavelengths are 775 and 720 nm, whose absorption rates are 0.118 and 0.066, respectively.

Fig. 2. Schematic of setup used for fs laser microprocessing.

Fig. 3. AFM image of micro-holes fabricated by fs laser with resonant wavelength of 807 nm.

Fig. 4. Comparison of depths processed on Pr–Nd glass and fused silica by fs laser with a single pulse at different wavelengths: (a) 720 nm; (b) 775 nm; (c) 807 nm. (d) Overall contrast between 720 and 807 nm.

Fig. 5. SLI matching micro-holes processed by resonant wavelength of 807 nm and the corresponding Keldysh parameter γ.