Laser-Heated Diamond Anvil Cell Technique: Double-Sided Heating with Multimode Nd:YAG Laser

A new laser heating system has been set up to minimize the sample temperature gradients both radially and axially in a diamond anvil cell. A multimode Nd:YAG laser with a relatively flat top of intensity profile allows us to reduce the radial temperature gradient; the axial temperature gradient is minimized by heating samples at both sides. Three dimensional uniform temperatures of 1200 4000 K are obtained at high pressures in samples with 20 50 μm (radial) diameter and 10 50 μm (axial) thickness. The radial and axial variations and temporal fluctuations of temperatures in specified volumes are of similar order and within 1-4%, depending on the temperature range with higher temperature in larger temperature variations. This technique provides a relatively large sample volume in a more homogenous temperature distribution relative to previous techniques. This is especially useful for in situ X-ray studies at simultaneous high pressures and high temperatures.