A double intracavity contacted structure developed at the University of California in Santa Barbara may lead to vertical-cavity surface-emitting lasers (VCSELs) that use lattice-matched distributed Bragg reflectors. Reporting in the March 5 issue of Applied Physics Letters, the research team described the successful fabrication of a 1560-nm VCSEL that features AlAsSb-based mirrors in an undercut mesa configuration.The team selectively etched an undercut aperture in the structure using a mixture of citric acid and hydrogen peroxide. The structure reduces heat in the device, enabling 1.05-mW, continuous-wave (CW) operation at 20 °C and CW operation up to 88 °C.