title: Percolation-enhanced generation of terahertz pulses by optical rectification on ultrathin gold films.
abstract: Emission of pulses of electromagnetic radiation in the terahertz range is observed when ultrathin gold films on glass are illuminated with femtosecond near-IR laser pulses. A distinct maximum is observed in the emitted terahertz amplitude from films of average thickness just above the percolation threshold. Our measurements suggest that the emission is through a second-order nonlinear optical rectification process, enhanced by the excitation of localized surface plasmon hot spots on the percolated metal film.
authors: Optics Research Group, Department of Imaging Science and Technology, Faculty of Applied Sciences, Delft University of Technology, Lorentzweg 1, 2628 CJ Delft, The Netherlands. G.Ramakrishnan@tudelft.nl
authors: Gopakumar
authors: G
authors: Ramakrishnan
authors: Paul C M
authors: PC
authors: Planken