Mid-IR plasmonics and photomodification with Ag films

P Nyga, Purdue Univ, Sch Elect & Comp Engn, Birck Nanotechnol Ctr
V. P. Drachev, Birck Nanotechnology Center, School of Electrical and Computer Engineering, Purdue University
Mark D. Thoreson, Birck Nanotechnology Center, Purdue University
V. M. Shalaev, Birck Nanotechnology Center and School of Electrical and Computer Engineering, Purdue University

Abstract

The optical properties of semicontinuous silver films have been studied in the mid infrared. The film extinction spectra are shown to be well tailored by the deposition conditions and post-fabrication photomodification with both nanosecond and picosecond laser pulses at 10.6 mu m. The photomodification results in a decrease of the extinction above the laser wavelength. We find that the induced changes in the optical responses of the films are both wavelength and polarization selective. This technique allows the creation of long-pass filters for the mid-IR range in accord with the earlier theory.