Fourier transform plasmon resonance spectrometer

Abstract

Nanophotonics is an emerging field of research aiming to control interaction of light with matter in nanometer scale. Electrons localized on metallic nanoparticles generate localized plasmon oscillations with interesting optical properties that can be used for various sensing applications. Spectroscopic sensing using plasmonic particles could provide more detailed information, however it requires bulky spectrometers which limits its applications. In this thesis, a nanometer scale Fourier Transform Plasmon Resonance (FTPR) spectrometer is presented. FTPR spectrometer consists of a nanometer slit-grove or slit-ridge plasmon interferometer with varying optical path. The inherent coherence of the surface plasmons propagating through the sub-wavelength holes yield high contrast spatial interference pattern. FTPR spectrometer converts this spatial interference pattern in to spectroscopic information using Fast Fourier Transform (FFT) algorithm. In our design, there is no need for a bulky dispersive spectrometer or dispersive optical elements. We anticipate that high sensitivity of surface plasmons together with spectroscopic information and nanometer dimensions provides new avenues for plasmonic sensors.