Fast P‐doped silicon bolometer for detecting heat pulses

A new detector of ballistic phonons is presented. It is a P‐doped Si bolometer realized on top of a (100)Si crystal by ion implantation. The open circuit responsivity of the bolometer is 8000 V/W and the response time less than 50 ns. Time‐resolved spectra of ballistic phonons propagating in the same Si crystal along the 〈100〉 direction are reported.