Measuring temperatures in a laser-heated diamond-anvil cell at Yale University

We describe a newly-built double-sided laser-heating system in the High-Pressure Diamond-Anvil Cell (DAC) Laboratory at Yale University. The system uses a single power-tunable 100W near-infrared fiber laser that is split into two beams and independently focused down to a ~20 μm spot on each side of the DAC. Temperature measurements are made using both the standard spectroradiometric method, which yields a 1-D temperature profile, and the recently developed four-color technique, which allows 2-D mapping of temperature and emissivity across the sample [Campbell, A. J., Rev. Sci. Inst., 79, 015108, 2008]. Simultaneous measurement of 1-dimensional spectroradometric and 2-dimensional four-color temperatures from the same sample yields a robust temperature map on one side of the sample while a second four-color measurement on the opposite side allows monitoring of temperature in three spatial dimensions as well as in time. Initial results document consistent temperature measurement by the two techniques. This system can be used to document melting in situ [as described by Campbell, 2008]. Additionally, this system can be used to map out temperature and corresponding temperature gradients for pressure- and temperature-quenched samples for chemical analysis in recovered samples.