Active control of a plasmonic metamaterial for quantum state engineering

TL;DR

This paper demonstrates the active control of a plasmonic metamaterial in the quantum regime, enabling tunable quantum channels for quantum state engineering through temperature modulation of gold nanorod arrays.

Contribution

It introduces an experimental method for actively controlling a quantum plasmonic metamaterial using external laser heating, advancing beyond passive systems.

Findings

Polarization response tunable by up to 33%

Experimental results match theoretical model predictions

Active control enables flexible quantum state engineering

Abstract

We experimentally demonstrate the active control of a plasmonic metamaterial operating in the quantum regime. A two-dimensional metamaterial consisting of unit cells made from gold nanorods is investigated. Using an external laser we control the temperature of the metamaterial and carry out quantum process tomography on single-photon polarization-encoded qubits sent through, characterizing the metamaterial as a variable quantum channel. The overall polarization response can be tuned by up to 33% for particular nanorod dimensions. To explain the results, we develop a theoretical model and find that the experimental results match the predicted behavior well. This work goes beyond the use of simple passive quantum plasmonic systems and shows that external control of plasmonic elements enables a flexible device that can be used for quantum state engineering.