"Cooperatively-enhanced atomic dipole forces in optically trapped nanodiamond containing NV centres in liquid"
University of Technology, Sydney
Thursday, 21 September 2017, h. 11:00
Sala Wataghin, Physics Department, via P. Giuria 1, Torino
We report on a new regime for optical trapping of diamond nanoparticles in liquid. While holding a nanodiamond (~150 nm) containing many NV centres (~103) at the focus of classical optical tweezers, we use a second laser slightly detuned from the dipole transition of the NVs. We measure a change in trap stiffness of ~10%. Remarkably, we show that our results must include collective effects - "superradiance" - between colour centres, which has never been reported before for solid-state systems at room temperature of the type Dicke proposed in 1954. We discuss how these resonant forces depend on (and can be enhanced by) the type, number, dipole strength and spectral linewidth of the centres.