Widely tunable single-photon source from a carbon nanotube in the Purcell regime

TL;DR

This paper demonstrates a widely tunable single-photon source using a carbon nanotube in a repositionable fiber micro-cavity, achieving significant Purcell enhancement and broad spectral tuning, advancing quantum communication technologies.

Contribution

It introduces a novel method to tune single-photon emission over a 4 THz range using a carbon nanotube in a micro-cavity, with detailed characterization and enhanced emission properties.

Findings

Achieved up to 6-fold Purcell enhancement.

Locked single-photon emission over a 4 THz bandwidth.

Observed efficient emission funneling into the cavity mode.

Abstract

Single-Wall Carbon Nanotubes (SWNTs) are among the very few candidates for single-photon sources operating in the telecom bands since they exhibit large photon antibunching up to room temperature. However, coupling a nanotube to a photonic structure is highly challenging because of the random location and emission wavelength in the growth process. Here, we demonstrate the realization of a widely tunable single-photon source by using a carbon nanotube inserted in an original repositionable fiber micro-cavity : we fully characterize the emitter in the free-space and subsequently form the cavity around the nanotube. This brings an invaluable insight into the emergence of quantum electrodynamical effects. We observe an efficient funneling of the emission into the cavity mode with a strong sub-Poissonian statistics together with an up to 6-fold Purcell enhancement factor. By exploiting the cavity feeding effect on the phonon wings, we locked the single-photon emission at the cavity frequency over a 4~THz-wide band while keeping the mode width below 80~GHz. This paves the way to multiplexing and multiple qubit coupling.