Stoichiometric neodymium gain media for diode laser pumped solid state lasers

Abstract

Stoichiometric neodymium gain materials are attractive alternatives to lightly doped crystals such as Nd:YAG for the construction of diode laser pumped, solid state lasers. Following the initial demonstration of laser action in NPP, laser performance of a number of stoichiometric compounds was investigated. During the 1970s, efficient laser emission near 1050 and 1320 nm was observed from several different compounds with argon-ion laser, dye laser, LED, and diode laser pumping.1 More recently, we have taken advantage of the short pump absorption length (40-100 μm) of LNP to build highly efficient, close-coupled cube lasers.2 In these devices, a plane-parallel platelet of LNP with directly applied mirrors (cube laser) is pumped by close coupling it to the output facet of a diode laser array. An output power of 136 mW in a circular, Gaussian mode with simultaneous output at 1047 and 1055 nm has been obtained at an efficiency of 46% from an LNP C2 cube laser housed in a standard TO-3 diode laser package. A single frequency output power of 35 mW was obtained from the same laser by changing the pumping conditions. We believe that these results, combined with the body of work performed during the 1970s, indicate that stoichiometric neodymium compounds will play an important role in the development of future diode laser pumped, solid state lasers. The combination of intense, spectrally broad pump absorption lines, long excited state lifetimes, and large stimulated emission cross sections make stoichiometric Nd compounds ideally suited as gain media for a variety of different devices.