Abstract

Excitons in suspended carbon nanotubes (CNT) constitute a promising alternative for both quantum optomechanics [1] and quantum photonics [2]. In both of these scenarios, it becomes important to understand their interactions with soft phonons. Here we focus on a CNT system where an inhomogeneous electric field induces strong exciton localisation, i.e. generates an optically active quantum dot, and induces a tunable parametric coupling of the exciton to the flexural modes of the nanotube mediated by deformation-potential interactions [1]. We calculate the corresponding phonon-broadened fluorescence spectra under weak laser excitation for large suspended CNT length. We show that, at low temperature, this regime realises the “localised” phase of a subohmic spin-boson model [3] with spectral density $J(\omega )\propto \sqrt{\omega }$, as evidenced by a “complete collapse” of the zero-phonon line (ZPL).

© 2015 IEEE