Fig. 1. (a) Schematic diagram of the VECSEL system; (b) distributions of the refractive index of each layer and the optical field within the gain chip.

Fig. 2. (a) Relationships between the In content and thickness of quantum wells when its emitting wavelength is 970, 975, 980 nm; (b) the gain spectra of different quantum wells with the same gain peak wavelength of 980 nm; (c) the valence subband structures of InGaAs QWs corresponding to a wavelength of 980 nm (HH1, the first heavy hole subband; LH1, the first light hole subband.).

Fig. 3. (a) The change of gain peak with the carrier density within quantum wells when the gain peak wavelength is 980 nm; (b) the change of material gain with the operating temperature.

Fig. 4. (a) The gain spectra and (b) the gain peak wavelength of 5 nm InGaAs quantum well at different opera-ting temperatures.

Fig. 5. (a) The gain spectra of InGaAs quantum well with different barrier layers; (b) the gain peak changing with the carrier density for different structures.

Fig. 6. The measured reflection spectra of the gain chip when the optical incident angle is 0°, 40°, and 70°.

Fig. 7. (a) The output power of VECSEL and (b) the lasing wavelength changing with the pump power, with the output mirror reflectivity of 99.1%, 97.7%, and 96.3%.

Fig. 8. The divergence angles of VECSEL along the orthogonal direction, inserted is the measured 2D optical spot pattern.