Continuous wave lasing from individual GaAs-AlGaAs core-shell nanowires

We demonstrate single-mode continuous wave (cw) lasing from individual GaAs-AlGaAs coreshell nanowires (NWs) subject to optical excitation. By comparing the s-shaped input-output characteristics of cw-excited NW lasers with those obtained under pulsed excitation at 4K, we observe a similar to 4x lower equivalent pump power for cw-excitation and a lower minimum lasing linewidth of similar to 200 mu eV, indicative of the steady-state excitation conditions that result in improved temporal coherence of the emission. Analysis of the NW cavity length dependence of the mode characteristics reveals a clear inverse scaling behavior, with the spacing of Fabry-Perot modes corresponding to a group refractive index of similar to 8. Remarkably, when subject to cw excitation heating of the NW-lasers is found to be negligible, as verified by a constant lasing linewidth as well as the absence of redshifted lasing peak emission at high excitation levels. (C) 2016 AIP Publishing LLC.