OPTICAL-ABSORPTION AND STIMULATED-EMISSION OF NEODYMIUM IN YTTRIUM ORTHOSILICATE

A spectroscopic investigation of the biaxial crystal yttrium orthosilicate doped with Nd3+ (Nd3:Y2SiO5) has been performed. Spectrally and orientationally resolved emission cross sections necessary for the evaluation of laser performance on the Nd3+ 4F3/2-4I9/2 and 4F3/2-4I11/2 transistions have been determined. The Judd-Ofelt theory has been applied to measured values of optical absorption line strengths to obtain the orientation averaged intensity parameters: Ω2 = 3.34 · 10 −20cm2, Ω4 = 4.35 · 10−20 cm2, and Ω6 = 5.60 · lO−20 cm2. These Judd-Ofelt intensity parameter values are significantly different than those previously reported by Tkachuk et al. [1]. Using these intensity parameters, the Nd3+ 4F3/2 metastable state lifetime is predicted to be 225 μs. Measured low Nd concentration 4F3/2 lifetimes of 214 μs indicate a high radiative quantum efficiency. Because of the fortuitous Stark level splitting of the Nd3+ 4F3/2 and 4I9/2 manifolds, laser operation at twice one of the Cs atomic resonance filter acceptance wavelengths is possible. © 1990 IEEE