Carbon nanotubes have recently proven to be promising nano-emitters for future single-photon sources in the telecom wavelengths [1,2,3]. Coupling the nanotube to a micro-cavity brings a invaluable handle to control single-photon emission, regarding the rate, the yield, the directionnality and the extraction. All those features are related to the so-called Purcell effect that results from the interaction of a quasi-two-level system with a high Q and low mode-volume optical cavity. In carbon nanotubes though, the situation is slightly more complex due to the intimate coupling of the excitonic levels with the acoustic phonon bath, resulting in the well-known phonon wings [4]. This additional degree of freedom brings a very rich physics that can be exploited to enlarge the bandwidth of the source in view of multiplexing. A consequence of the non-Markovian decoherence induced by the phonon bath is the asymetry between the phonon-assisted absorption and emission processes. Using those transitions in the Purcell regime can lead to an enhanced single-photon efficiency above the standard limit imposed by the emitter and cavity intrinsic losses. We developped a widely tunable cavity technique, based on laser-engineered optical fibers to investigate this effect. We measure the single-photon emission properties both in the cw and time-resolved modes and explain the strong asymetry of the efficiency with respect to the detuning.

[1] A. Jeantet et al., Phys. Rev. Lett. 116, 247402 (2016)

[2] S. Khasminskaya et al., Nat. Phot. 10, 727 (2016)

[3] X. Ma, et al., Nat. Mat. 10, 671 (2015)

[4] F. Vialla et al., Phys. Rev. Lett. 113, 057402 (2013)