Excitation of ruby fluorescence at multimegabar pressures

We demonstrate the excitation of strong rubp fluorescence at multimegabar pressures by red incident radiation. We have studied the ruby R(1) and N-2 lines to 251 GPa and measured the R(1) line intensity as a function of pump wavelength. This new method of exciting ruby fluorescence enables easy pressure determination at pressures beyond the 250 GPa limit previously predicted by Ruoff. (C) 1996 American Institute of Physics.