Measurement of R Line Fluorescence in Ruby Using the Diamond Anvil Cell at Low Temperature

Using our custom-built high-pressure cryostat we have performed the measurements of the R line fluorescence of ruby in the diamond anvil cell from room temperature down to 90 K. The maximum pressure was 11.1 GPa. By computer curve fitting, different equations have been found for functions of wavenumber versus temperature between ambient pressure and 2.7 GPa. The changes of the shape and linewidth of R lines were observed.