Optical characterization of Nd3+ doped sulphide glasses

Optical properties of chalcogenide glasses doped with Nd3+ are presented in the paper with a brief description of the samples preparation. In these glasses, low electronegativity ligands (Na+) are used to improve the optical properties. Large transition strengths are observed in these materials and from these we calculate an emission cross-section of 8 +/- 0.3 X 10(-20) cm(2) at 1.08 mu m with a full width at half medium of 35 nm. For 0.8 +/- 0.05 X 10(20) Nd3+ ions/cm(3) the experimental lifetime is 110 +/- 3 mu s, in good agreement with the calculated value revealing the absence of non-radiative de-excitation. From the spectroscopic parameters, the laser threshold in cw laser operation is calculated to be larger than 300 mW for a 96% output mirror reflectivity. At that power, in our configuration, thermal lensing effects prevent laser oscillation.