Two-Path Solid-State Interferometry Using Ultra-Subwavelength 2D Plasmonic Waves

TL;DR

This paper demonstrates a novel on-chip Mach-Zehnder interferometer using ultra-subwavelength 2D plasmonic waves at microwave frequencies, achieving significantly higher resolution than traditional electromagnetic interferometers.

Contribution

It introduces a new solid-state interferometer based on 2D plasmonic waves with ultra-subwavelength confinement, scalable to higher frequencies and room temperature operation.

Findings

Achieved a plasmonic wave velocity of ~c/300.

Interferometer resolution is two orders of magnitude higher than electromagnetic counterparts.

Proof-of-concept demonstrated at microwave frequencies with potential for THz IR range.

Abstract

We report an on-chip solid-state Mach-Zehnder interferometer operating on two-dimensional (2D) plasmonic waves at microwave frequencies. Two plasmonic paths are defined with GaAs/AlGaAs 2D electron gas 80 nm below a metallic gate. The gated 2D plasmonic waves achieve a velocity of ~c/300 (c: free-space light speed). Due to this ultra-subwavelength confinement, the resolution of the 2D plasmonic interferometer is two orders of magnitude higher than that of its electromagnetic counterpart at a given frequency. This GHz proof-of-concept at cryogenic temperatures can be scaled to the THz IR range for room temperature operation, while maintaining the benefits of the ultra-subwavelength confinement.