Thin slab and planar waveguide solid state lasers

This thesis studies the design, engineering and operation of a new type of solid state laser based on face pumping of optically thin slabs of gain medium by laser diode bars. The efficient pumping of thin slabs is achieved by multiple pass of the pump radiation in a rectangular geometry pumping chamber. Several gain media have been reviewed in order to select the material which yields the best possible results with this pumping system and maximizes the efficiency of the laser. Nd:glass and Nd:YAG have been selected to perform preliminary studies. The pumping sources have been characterized in order to obtain maximum effective absorption per pass. The design and engineering of the pumping chamber serves to minimize the losses per pass. Different cooling systems of the gain medium have been carefully designed and tested in experimental prototypes. The efficient injection of the pump radiation inside the chamber has been achieved with the introduction of the ''slotted mirror'' concept. As a result of the studies carded out for face pumping of thin slabs of gain media, a planar waveguide slab laser is presented. This waveguide is produced in a composite slab made up of a 200 #mu#m Nd:YAG core and undoped YAG as claddings. The system is operated with a pumping efficiency of up to 50%, optical-optical efficiency of 24%, high gain, and mode control in the waveguide direction of the slab. The thesis also describes a matrix method developed to carry out pumping efficiency calculations. Using this method, efficiencies of the order of 90% were obtained for Nd:glass slabs of 1.0 mm thickness, and as high as (50-60)% for Nd:YAG slabs as thin as 0.2 mm thick. (author)Available from British Library Document Supply Centre-DSC:DXN035751 / BLDSC - British Library Document Supply CentreSIGLEGBUnited Kingdo