Optical characteristics of VCSEL pumped microchip lasers

Vertical-cavity surface-emitting lasers (VCSELs) have been used to opticall y 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 VCS EL. The microchip laser operates in a fundamental Gaussian mode of 40-50 mu m diameter for a range of pump sizes from 10 to 50 mum with a threshold pum p power proportional to the pump size. These characteristics indicate that the mode formation is controlled by gain-induced refractive index changes w ithin a cavity that is positively detuned from the atomic resonance. Stable , Gaussian mode formation is also achieved when directly pumping the microc hip lasers with no intervening optics. (C) 2001 Elsevier Science B.V. All r ights reserved.