Quantized optical near-field interactions measured with a superconducting nanowire detector

TL;DR

This paper demonstrates direct measurement of quantum optical near-field interactions using a superconducting nanowire detector, enabling high-resolution imaging and sensing at the quantum level.

Contribution

It introduces a novel method employing a superconducting nanowire detector to directly measure quantum near-field interactions with high spatial resolution.

Findings

Near-field interactions are well described by evanescent source fields.

The method achieves single-photon sensitivity in near-field measurements.

No significant probe-sample coupling observed in the measurements.

Abstract

The quantum nature of optical near-fields is interesting from a theoretical perspective and of importance for practical applications, such as high-resolution imaging, sensing and antenna-coupled quantum light sources. In this work we use a custom-designed superconducting nanowire single-photon detector (SNSPD) to directly read out the near-field interaction between source and detector. We use a subwavelength-sized aperture at the end of an optical fiber to record spatial near-field maps and to measure the distance dependence of the optical near-field interaction. Our measurements can be well described by a superposition of evanescent source fields with no noticeable probe-sample coupling. Our approach can be used for further studies of quantum near-field interactions and for the development of near-field imaging techniques with single quantum sensitivity.