Optical-domain spectral super-resolution via a quantum-memory-based time-frequency processor

TL;DR

This paper introduces a quantum-memory-based spectral measurement technique that surpasses the Rayleigh limit in optical spectroscopy, achieving higher resolution with fewer photons by exploiting full spectral information.

Contribution

The authors develop a novel quantum-inspired measurement method using a quantum memory to perform time-inversion interferometry, enabling super-resolution in optical spectroscopy.

Findings

Achieves 15 kHz spectral resolution.

Uses 20 times fewer photons than conventional methods.

Outperforms traditional spectroscopy and heterodyne measurements.

Abstract

Existing super-resolution methods of optical imaging hold a solid place as an application in natural sciences, but many new developments allow for beating the diffraction limit in a more subtle way. One of the recently explored strategies to fully exploit information already present in the field is to perform a quantum-inspired tailored measurements. Here we exploit the full spectral information of the optical field in order to beat the Rayleigh limit in spectroscopy. We employ an optical quantum memory with spin-wave storage and an embedded processing capability to implement a time-inversion interferometer for input light, projecting the optical field in the symmetric-antisymmetric mode basis. Our tailored measurement achieves a resolution of 15 kHz and requires 20 times less photons than a corresponding Rayleigh-limited conventional method. We demonstrate the advantage of our technique over both conventional spectroscopy and heterodyne measurements, showing potential for application in distinguishing ultra-narrowband emitters, optical communication channels, or signals transduced from lower-frequency domains.