2022 article

A Nanophotonic Interferometer for small particle detection


By: A. Ghaffari, K. Do n, S. Kashani n, K. Weninger n & R. Riehn n

author keywords: zero mode waveguide; sub-wavelength aperture; interferometer
Source: Web Of Science
Added: November 7, 2022

The transmission of light through sub-wavelength apertures (zero-mode waveguides, ZMW) in metal films is wellexplored. It introduces both an amplitude modulation as well as a phase shift to the transmitted oscillating electromagnetic field. We propose a nanophotonic interferometer by bringing two zero-mode waveguides in proximity and monitoring the distribution of light in the back-focal plane of the collecting microscope objective. We demonstrate that both an asymmetry induced by the binding of a quantum dot in one of the two ZMW, as well as a asymmetry in ZMW diameter yield qualitatively similar deflection patterns. Using ZMW pairs with diameter asymmetries, we find that the complex pattern of the transmitted light can be quantified through a scalar measure of asymmetry along the symmetry axis of the aperture pair. We find that this scalar asymmetry is a monotonous function of the diameter difference of the two apertures.