Hybrid Bridgman anvil design: an optical window for in situ spectroscopy in large volume presses

The absence of in situ optical probes for large volume presses (LVPs) often limits their application to high-pressure materials research. In this article, we present a unique anvil/optical window design for use in LVPs, which consists of an inverted diamond anvil seated in a Bridgman-type anvil. A small cylindrical aperture through the Bridgman anvil ending at the back of diamond anvil allows optical access to the sample chamber and permits direct optical spectroscopy measurements, such as ruby fluorescence (in situ pressure) or Raman spectroscopy. The performance of this anvil design has been demonstrated by loading KBr to a pressure of 14.5 GPa.