Subwavelength line imaging using plasmonic waveguides

TL;DR

This paper demonstrates a plasmonic waveguide array capable of subwavelength imaging at near-infrared wavelengths, achieving high resolution and low losses through tapered channels and optimized couplers, with potential applications in high-resolution detection and writing.

Contribution

The study introduces a novel two-dimensional plasmonic waveguide design that enables subwavelength imaging with high resolution and low propagation losses, advancing near-infrared optical imaging technology.

Findings

Point sources separated by λ/15 are distinguishable.

Up to 90% of a point dipole's power couples into the device.

High-resolution imaging is achieved with low propagation losses.

Abstract

We investigate the subwavelength imaging capacity of a two-dimensional fanned-out plasmonic waveguide array, formed by air channels surrounded by gold metal layers for operation at near-infrared wavelengths, via finite element simulations. High resolution is achieved on one side of the device by tapering down the channel width while simultaneously maintaining propagation losses of a few dB. On the other, low-resolution side, output couplers are designed to optimize coupling to free space and to minimize channel cross talk via surface plasmons. Point sources separated by {\lambda}/15 can still be clearly distinguished. Moreover, up two 90% of the power of a point dipole is coupled to the device. Applications are high-resolution linear detector arrays and, by operating the device in reverse, high-resolution optical writing.