Experimental identification of vacuum heating at femtosecond-laser-irradiated metal surfaces

Abstract

The existence of a vacuum heating (VH) contribution to absorption of high-intensity ultrafast laser pulses at solid targets has been predicted. The absorption occurs when electrons are drawn from a metallic surface by an intense, obliquely incident p-polarized laser field with Lλ2≳1014Wμm2, and driven back to the surface with approximately the quiver velocity. Simulations predict that this is an important absorption mechanism for both discrete surfaces and density gradients of scale length L≲xasc, where xasc= eE/mw2is the electron quiver amplitude.