PRESSURE-DEPENDENCE OF THE FLUORESCENCE-SPECTRA OF THE SM-DOPED YAG TO 73 GPA

The pressure dependence of the fluorescence spectra of the Sm-doped YAG optical pressure sensor is studied against the ruby in the diamond anvil cell up to 73 GPa. The Y-2 band fluorescence excited by a 514.5 nm laser shows a linear pressure dependence of 0.32 +/- 0.01 nm/GPa to 73 GPa. The relative intensity of the Y-2 sub-band compared to the Y-1 shows a significant increase with increasing pressure. At high pressures, the overall integrated intensity of the Y band increases by an order of magnitude which is in contrast to the ruby R(1) line whose intensity decreases under identical conditions. X-ray diffraction studies show that the cubic phase of the YAG crystal is stable to 69 GPa and the volume compression is 17.9%. The increase in the fluorescence intensity of the Sm:YAG with increasing pressure has practical applications in the ultra high pressure/high temperature research.