Optical spectroscopy and diode-pumped laser performance of Nd3+ in the CNGG crystal

We have exploited the broad absorption and emis-
sion bandwidth of the laser crystal Ca3(NbGa)2-xGa3O12 doped
with Nd to develop a tunable and mode locked diode-pumped
1-um laser. We also present the fluorescence and excitation
spectra at different crystal temperatures from 10 to 298 K. The
spontaneous transition probabilities, the branching ratios, and the
radiative lifetime are calculated by means of the Judd–Ofelt theory and compared with the experimental results. The stimulated emission cross-sections of the most important transitions have been calculated and compared with laser results. Employing a 2-W laser diode as a continuous-wave pump source, we have been able to tune the emission wavelength in the range 1053–1074 nm. Active mode-locking yielding pulses of 9.6, 18, and 19.7 ps at the three main emission peaks of 1058.6, 1061.2, and 1065.3 nm, respectively, was also demonstrated.