# 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.

## Key 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.

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Source: https://tomesphere.com/paper/1904.10652