The diamond anvil cell (DAC) has been used extensively in the study of solids and liquids at high pressure. For liquids it is necessary to use a metal gasket to retain the sample between the anvil faces. The pressure experienced by the fluid can be measured by including a small fragment of ruby, the fluorescence spectrum of which is sensitive to pressure. Several experimental arrangements for observing Raman spectra from a DAC have been tried. For 0° scattering, in which the laser passes straight through the cell, scattered light can be collected with an off-axis elliptical mirror which focuses it onto the entrance slit of the monochromator. Another technique uses a small mirror 15° off normal incidence to the DAC by which the laser is focused onto the sample. A lens then collects the near 180° scattered light and brings it to a focus at the monochromator.
D. J. Gardiner, M. Bowden, J. Daymond, A. C. Gorvin, and M. P. Dare-Edwards, "A Raman Microscope Technique for Studying Liquids in a Diamond Anvil Cell," Appl. Spectrosc. 38, 282-284 (1984)