Semiconductor Diode Laser Pumped Upconversion Laser
Original Publication Date: 1987-May-01
Included in the Prior Art Database: 2005-Feb-02
An upconversion laser, i.e., one operating at a wavelength shorter than that of the pump, consists of a rare earth laser medium that is longitudinally pumped by coherent infrared diode laser radiation. For most efficient use of the pump light two diode lasers should be used. The wavelengths of these narrow band diode lasers can be accurately tuned to match the spectrally narrow (typically 0.1-0.5nm) absorption transitions that are involved in the stepwise upconversion excitation. In a longi- tudinal pumping arrangement very high pump power densities can be achieved by tight focusing of the diode laser radiation. A dichroic beam splitter is used to extract the laser energy in a direction perpendicular to the laser axis.