Silicon radiation at a shock compression pressure of $68$ GPa and during unloading into a vacuum

In this study, the brightness temperatures of silicon shock-compressed to a pressure of $P = 68$ GPa and the evolution of its temperature during unloading are measured. The measurements were carried out in the infrared range $\Delta \lambda_1 = 1.1$–$1.7~\mu$m, in which silicon is optically transparent, and in the visible range $\Delta \lambda_2 = 0.32$–$1.06~\mu$m. The isentropic unloading of shock-compressed silicon into a vacuum is accompanied by an anomalous increase in the observed temperature.