Fig. 1. (a) The epitaxial structure of the gain chip, (b) the DBR reflectivity, surface-emitting PL spectrum, and laser spectrum, (c) the surface-emitting PL spectra under various temperatures, (d) the peak wavelengths of surface-emitting PL spectra versus temperatures, (e) the surface-emitting PL spectra under various pump powers, and (f) the peak wavelengths of surface-emitting PL spectra versus pump powers.

Fig. 2. (a) Schematic and (b) photograph of the experimental setup of the CW/SML UV SDL.

Fig. 3. The UV output powers of the CW SDL. The inset at the lower right corner is the spectrum of the UV laser.

Fig. 4. (a) Autocorrelation trace, (b) the mode-locked pulse train, and (c) the RF spectrum, including the second-, third-, and fourth-harmonics of the SML SDL.

Fig. 5. UV output powers versus pump powers of the SML SDL. The insets at the upper left corner and lower right corner are the M² factors of beam quality and the UV spectrum.