Crystal growth, thermal and laser properties of neodymium-doped strontium fluorapatite

In this paper, the neodymium-doped strontium fluorapatite crystal has been grown by the Czochralski method. The data of thermal expansion and specific heat of the crystal have been measured. The thermal expansion coefficients along X and Z direction are alpha(1) = 11.4 x 10(-6)/K and alpha(3) = 12.3 x 10(-6)/K respectively. The specific heat is 110 cal/mol.K at 330 K. The measured absorption spectra from 400 nm to 850 nm show that the crystal has absorption peaks around 805.5 nm, and the absorption coefficients at 805.5 nm are 16.05 cm(-1) and 5.59 cm(-1) for pi and sigma polarization respecti vely. The polarization fluorescence spectra at room temperature show that t he strongest fluorescence is centered at 1058.8 nm. The lifetime of F-4(3/2 ) is 175 mu s for 1 at.% Nd3+ doped in the crystal. The laser at 1058.8 nm is demonstrated pumped by a 3W cw laser diode at 805.5 nm, and the slope ef ficiency is 31.7%.