We demonstrate the excitation of strong rubp fluorescence at multimega
bar 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 fu
nction of pump wavelength. This new method of exciting ruby fluorescen
ce enables easy pressure determination at pressures beyond the 250 GPa
limit previously predicted by Ruoff. (C) 1996 American Institute of P
hysics.