Gain spectroscopy of a type-Ⅱ VECSEL chip

摘要

Using optical pump-white light probe spectroscopy, the gain dynamics is investigated for a vertical-external-cavity surface-emitting laser chip, which is based on a type-Ⅱ heterostructure. The active region of the chip consists of a GaAs/(GaIn)As/Ga(AsSb)/(GaIn)As/GaAs multiple quantum well. For this structure, a fully microscopic theory predicts a modal room temperature gain at a wavelength of 1170nm, which is confirmed by the experimental spectra. The results show a gain buildup on the type-Ⅱ chip that is delayed relative to that of a type-Ⅰ chip. This slower gain dynamics is attributed to a diminished cooling rate arising from the reduced electron-hole scattering.