Intense thermal terahertz-to-infrared emission from random metallic nanostructures under femtosecond laser irradiation

• DOI: 10.1364/oe.23.014211
• Publication Date: 2015-05-21T16:23:48Z
• Authors: Liangliang Zhang; Kaijun Mu; Ji Zhao; Tong Wu; Hai Wang; Cunlin Zhang; X.-C. Zhang
• Keywords: 02 engineering and technology; 0210 nano-technology; 7. Clean energy

We report intense (~10 mW), ultra-broadband (~150 THz wide), terahertz-to-infrared, Gaussian-wavefront emission from nanopore-structured metallic thin films under femtosecond laser pulse irradiation. The proposed underlying mechanism is thermal radiation. nanostructures of the metal film are produced by random holes in substrate. Under pulse-train irradiation, we found dramatically enhanced optical absorption, with an absorptivity that was equal to as much 95% surface nanostructure, due both antireflection and dissipation excited plasmon polaritons into surface.