A diamond anvil cell for advanced microscopic observations and its application to the study of crystal growth under pressure

A new type of diamond anvil cell has been designed for microscopic observations under pressure with high‐resolution and high‐magnification capability. The cell allows the use of objective lenses with working distances as small as 6 mm, resulting in a typical objective magnification of 40× (total magnification of ∼800×), and facilitating advanced microscopic techniques such as the differential interference method and the dark‐field method. The aberration by diamond can be reduced significantly by optimizing its thickness, with the use of objective lenses corrected for optical windows like quartz or glass. Pressure can be changed smoothly with the use of bellows without disturbing the observation. A microscopic observation system incorporating the present cell has been employed successfully to the study of crystal growth under pressure from an aqueous solution.