The basic principle of the diamond indenter cell is very simple - by applying force to small areas, extremely high pressures are generated in accordance with the relationship p = F/A.

Schematic sketch of a diamond anvil cell (DAC) and microscope image of the sample chamber with sample and pressure calibrantsA cell of this type measures just a few centimetres in diameter and is constructed as follows: The centrepiece within the cell is formed by two opposing diamonds with a special cut - so-called diamond stamps. An extremely small sample space with a diameter of a few hundred micrometres is created between their flattened tips. The microscopically small sample is placed in a hydrostatic pressure medium.

Diamond as a material is particularly suitable for spectroscopic experiments in which the sample can be analysed directly - in situ - under ultra-high pressure conditions due to its extreme hardness and high optical transparency. Nowadays, there are a variety of models that can be used to set not only pressure but also temperature and conduct research in the ultra-low and high-temperature range. Depending on the geometry, pressures in the high GPa range and temperatures from liquid helium (-269 °C) to several 1000 °C can be generated. This makes it possible to create conditions similar to those inside the earth.

The precise control of pressure and temperature also makes it possible to extend known phase diagrams of different materials by orders of magnitude and thus explore new, exciting materials and their properties.