In situ spectroscopy of high-power vertical-external-cavity surface-emitting lasers

Abstract

Spectroscopic techniques for an in situ analysis of vertical‐external‐cavity surface‐emitting lasers are presented and exemplary results are discussed. Spatially resolved photoluminescence is shown to provide access to the temperature distribution inside the active area of the laser chip. Both the shape and the size of the pump spot are found to strongly influence the thermal properties and the output power of the device. In addition, the temporal stability of a laser emitting at two distinct wavelengths is studied using single‐shot streak‐camera measurements. The collected data is evaluated via quantitative statistical analysis schemes identifying stable and unstable regimes of operation.

Optically pumped VECSELs: review of technology and progress

“…However, the spatial resolution was only 60 µm and, therefore, suitable only for relatively large pump spots. Later on, Chernikov et al measured the VECSEL temperature by collecting the PL emission from the gain element using a large aperture lens [213,214]. The main finding was that a uniform pump intensity distribution minimized the peak temperature in the VECSEL gain element, which permitted significantly higher output powers than were obtained with a Gaussian pump intensity distribution.…”