Quantum Tomography of the Photon-Plasmon Conversion Process in a Metal Hole Array

TL;DR

This paper presents a comprehensive quantum process tomography of photon-plasmon conversion in a metal hole array, revealing detailed amplitude and phase information crucial for advancing quantum plasmonic devices.

Contribution

It provides the first complete quantum characterization of photon-plasmon conversion, enabling better understanding for on-chip quantum plasmonic applications.

Findings

Reconstructed the process tensor of photon-plasmon conversion.

Extracted amplitude and phase information of the process.

Demonstrated fundamental quantum process for future plasmonic circuits.

Abstract

In the past decades, quantum plasmonics has become an active area due to its potential applications in on-chip plasmonic devices for quantum information processing. However, the fundamental physical process, i.e., how a quantum state of light evolves in the photon-plasmon conversion process, has not been clearly understood. Here, we report a complete characterization of the plasmon-assisted extraordinary optical transmission process through quantum process tomography. By inputting various coherent states to interact with the plasmonic structure and detecting the output states with a homodyne detector, we reconstruct the process tensor of the photon-plasmon conversion process. Both the amplitude and phase information of the process are extracted, which explains the evolution of the quantum-optical state after the coupling with plasmons. Our experimental demonstration constitutes a fundamental block for future on-chip applications of quantum plasmonic circuits.