The employment of high-pressure gases as a pressure-transmitting medium, sample, or
reactant for diamond anvil cell experiments is widespread. As a pressure transmitter, high-
pressure gases are crucial to forming quasi-hydrostatic compression atmospheres for
samples inside the uniaxially driven cell. We describe an optical design for forming high-
resolution images of the gasket and sample chamber of the diamond anvil cell under high
gas pressures in a gas loading apparatus. Our design is simple, is of low-cost, and may be …