LASER, OPTICAL, AND THERMOMECHANICAL PROPERTIES OF YB-DOPED FLUORAPATITE

The laser performance of Yb-doped fluorapatite (Ca5(PO4)3F or FAP), is assessed by employing a Ti:sapphire laser operating at 905 nm as the pump source. We have measured slope efficiencies to be as high as 79%; the residual decrement from the quantum defect-limited efficiency of 87% is accounted for by the presence of passive loss at the 1043-nm la ser wavelength. The important spectral properties of Yb:FAP were evalu ated, including the absorption and emission cross sections, excited-st ate lifetime, and ground-state energy-level splitting. The emission an d absorption cross sections of Yb3+ in FAP are found to be substantial ly larger than those of other Yb-doped media. The thermal, physical, a nd optical properties of the FAP host are reported as well.