Modal refractive index measurement in nanowire lasers-a correlative approach

We present a method to correlate multimodal measurements-namely optical spectroscopy and electron microscopy-over large ensembles of randomly distributed single nano-objects. Using an algorithmic approach derived from astrometry, a marker-free method of uniquely associating nano-objects characterised using multiple techniques is described. This approach is applied to nanolasers, enabling an experimental calculation of modal refractive index in sub-micron diameter nanowires. By matching the lasing spectrum and electron microscopy image of 13 nanowire lasers, the refractive index of the TE01 mode in GaAs/AlGaAs multiple-quantum well nanolasers is determined to be n(g) = 4.7 +/- 0.3.