Broadband emission from polycrystalline graphite

Visible radiation spectra of polycrystalline graphite under electrical and laser excitation is studied. It is shown that two different mechanisms of photon emission with a broadband spectrum are implemented in this material. The radiation arising as a result of resistive heating is thermal radiation, whose parameters are close to those of blackbody radiation. The laser-induced secondary radiation in the visible range is anti-Stokes luminescence. A red shift of the laser-induced radiation from fine-grained graphite with respect to the similar spectrum of a bulk sample is observed.