Carbon nanotubes have strong assets for future integrated single-photon sources since their working wavelength can easily be tuned to the telecom C band by choosing an appropriate diameter [1]. In addition, they show a pronounced antibunching both at low and room temperature[2,3]. Nevertheless, the practical implementation of such a single-photon source requires to embed the nanotube into a micro-cavity in order to funnel the emitted photons into a specific mode (and possibly to an optical fiber) and in order to beat the non-radiative recombination by means of Purcell brightening. In order to tackle the stringent spatial and spectral matching conditions, we developed a flexible micro-cavity design where the concave mirror is micro-engineered at the apex of a single mode optical fiber [4] that can be scanned at the surface of the back mirror where nanotubes has been deposited.

By doing so, we are able to observe, both by means of photon counting and time-resolved measurements a Purcell effect of the order of 6, which allows us to funnel 90% of the photons into the mode [5]. In addition, by exploiting the cavity feeding effect on the phonon side-bands, we are able to tune the source over a 5 THz spectral window while keeping a high spectral purity (80 GHz) and an anti-bunching rate better than 0.01.

[1] V. Ardizzone et al. Phys. Rev. B 91, 121410 (R) (2015)

[2] Hogele et al. Phys. Rev. Lett. 100, 217401 (2008)

[3] Ma et al. Nature nano. 10, 671 (2015)

[4] Hunger et al. N. J. Phys 12, 065038 (2010)

[5] Jeantet et al., arXiv1508:06297 (2015)