Quantum optical signal processing in diamond

TL;DR

This paper demonstrates spectral manipulation of single photons stored in a room-temperature diamond crystal, enabling frequency tuning and bandwidth control, advancing integrated quantum photonic technologies.

Contribution

It introduces a method for coherent spectral control of single photons in diamond, including frequency tunability and bandwidth modulation, using a modified quantum memory.

Findings

Achieved storage of 723.5 nm photons with 4.1 nm bandwidth in diamond.

Demonstrated frequency tunability over 4.2 times the input bandwidth.

Showed bandwidth modulation between 0.5 to 1.9 times the input bandwidth.

Abstract

Controlling the properties of single photons is essential for a wide array of emerging optical quantum technologies spanning quantum sensing, quantum computing, and quantum communications. Essential components for these technologies include single photon sources, quantum memories, waveguides, and detectors. The ideal spectral operating parameters (wavelength and bandwidth) of these components are rarely similar; thus, frequency conversion and spectral control are key enabling steps for component hybridization. Here we perform signal processing of single photons by coherently manipulating their spectra via a modified quantum memory. We store 723.5 nm photons, with 4.1 nm bandwidth, in a room-temperature diamond crystal; upon retrieval we demonstrate centre frequency tunability over 4.2 times the input bandwidth, and bandwidth modulation between 0.5 to 1.9 times the input bandwidth. Our results demonstrate the potential for diamond, and Raman memories in general, to be an integrated platform for photon storage and spectral conversion.