Optical properties and laser performance of neodymium doped fluoroapatites SrxCa5-x(PO4)(3)F (x=0, 1, 2, 3, 4, and 5)

Nd doped fluoroapatites SrxCa5-x(PO4)(3)F (SxC5-x PF, x = 0, 1, 2, 3, 4, and 5) single crystals have been grown by the Czochralski technique. Their polarized absorption and emission spectra have been recorded at room temperature and used to calculate the absorption and stimulated emission cross sections. Broadening of the absorption and emission bands is observed for Nd3+ in the solid solutions SPF-CPF compared to Nd3+ in CPF or SPF. 1% Nd:SxC5-xPF, x = 0, 2, 3, 4, and 5, laser rods have been tested in a cavity longitudinally pumped by a 1 W AlGaAs laser diode and compared to Nd:YAG and Nd:YVO4 rods. All fluoroapatites exhibit very good laser performance with low thresholds and high slope efficiencies, higher than in the case of YAG and equal to the YVO4 samples. The dependance of the laser output power versus the diode temperature has also been measured for all materials. The laser output was found to be as sensitive to the diode temperature fluctuations for fluoroapatites as for YAG.