Reflectance thermometry in dynamic compression experiments

Ultrafast compression provides unique insights into material behavior at extreme conditions. Starting from ambient conditions, compressed samples can reach pressures of 1-100+ GPa, accompanied by temperature changes of 102-105 K, within 10-100 ns. Dynamic temperature measurements of these states provide a wealth of thermodynamic information but are challenging in single-event experiments. Optical pyrometry can be used in some situations but becomes infeasible below 1000 K. Instead of inferring temperature based on light emitted by a sample, we propose to measure dynamic temperature states based on light reflected from a sample. As an active measurement, reflectance thermometry yields measurable optical signals at any temperature, potentially with nanosecond time resolution.