Optical absorption and stimulated emission of neodymium in yttrium orthosilicate

A spectroscopic investigation of the biaxial crystal yttrium orthosilicate doped with Nd/sup 3+/(Nd/sup 3+/:Y/sub 2/SiO/sub 5/) has been performed. Spectrally and orientationally resolved emission cross sections necessary for the evaluation of laser performance on the Nd/sup 3+/ /sup 4/F/sub 3/2/-/sup 4/I/sub 9/2/ and /sup 4/F/sub 3/2-//sup 4/I/sub 11/2/ transitions 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: Omega /sub 2/-3.34*10/sup -20/ cm/sup 2/, Omega /sub 4/=4.35*10/sup -20/ cm/sup 2/, and Omega /sub 6/=5.60*10/sup -20/ cm/sup 2/. These Judd-Ofelt intensity parameter values are significantly different from those previously reported by A.M. Tkachuk et al. Using these intensity parameters, the Nd/sup 3+/ /sup 4/F/sub 2/ metastable state lifetime is predicted to be 225 mu s. Measured low Nd concentration /sup 4/F/sub 3/2/ lifetimes of 214 mu s indicate a high radiative quantum efficiency. Because of the Stark level splitting of the Nd/sup 3+/ /sup 4/F/sub 3/2/ and /sup 4/I/sub 9/2/ manifolds, laser operation at twice one of the Cs atomic resonance filter acceptance wavelengths is possible.<
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