Raman spectra of culet face of diamond anvils and application as optical pressure sensor to high temperatures

The shift in frequency of the first-order Raman band of diamond with changing pressure and temperature was calibrated for application as a Raman spectroscopic pressure sensor in diamond anvil cells to 800 K and 106 GPa. The pressure dependence is nearly linear at pressures below 40 GPa. However, deviation of the pressure dependence from the linear equation has been confirmed at higher pressures. The frequency decreases with increasing temperature at ambient pressure. The temperature dependence is small with an increasing pressure, as determined from experiments conducted along isotherms up to 106 GPa. The relationship between the shift of this band and temperature can be described by a polynomial equation. Therefore, this pressure sensor has the advantage that it is not necessary to mix any additional calibration materials with the samples in the diamond anvil cell experiments. (C) 2014 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution 3.0 Unported License.