Optical access to the large volume, high pressure environment

A new technique of gaining optical access to the large volume, high pressure environment using optical fibers is reported. High pressure experiments of light transmission through optical fibers brought out through the gasket region in optically opaque, solid medium cubic anvil pressure cells have been performed in a large volume cubic apparatus. Photographic records of the transmitted light signal, taken at constant pressure settings, demonstrate optical continuity up to pressures of 12 kbar on metal tube-encased fibers. Progressive degradation in light intensity is observed with increasing pressure. Time exposure photographs taken during loading track the movement of the fiber in the gasket during extrusion. At pressures above 14 kbar, the maximum pressure of optical continuity through a fiber in this study, microbending of the fiber in the gasket region causes fracture and termination of the optical path. (C) 1998 American Institute of Physics. [S0034-6748(98)00207-X].