Optical characteristics of VCSEL pumped microchip lasers

Vertical-cavity surface-emitting lasers (VCSELs) have been used to optically pump a planar-cavity, Nd:YVO4 Microchip laser. Lasing was achieved with a minimum pump power of 0.8 mW from a 10 mum diameter, circular aperture VCSEL. The microchip laser operates in a fundamental Gaussian mode of 40-50 mum diameter for a range of pump sizes from 10 to 50 mum with a threshold pump power proportional to the pump size. These characteristics indicate that the mode formation is controlled by gain-induced refractive index changes within a cavity that is positively detuned from the atomic resonance. Stable, Gaussian mode formation is also achieved when directly pumping the microchip lasers with no intervening optics. (C) 2001 Elsevier Science B.V. All rights reserved.