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

• Published in: Applied physics letters Vol. 108; no. 7
• Main Authors: Mayer, B., Janker, L., Rudolph, D., Loitsch, B., Kostenbader, T., Abstreiter, G., Koblmüller, G., Finley, J. J.
• Format: Journal Article
• Language: English
• Published: Melville American Institute of Physics 15.02.2016
• Subjects: Aluminum gallium arsenides; Applied physics; Continuous radiation; Dependence; Emission analysis; Excitation; Gallium arsenide; Laser beam heating; Lasing; Nanowires; Refractivity
• ISSN: 0003-6951; 1077-3118
• DOI: 10.1063/1.4942506

We demonstrate single-mode continuous wave (cw) lasing from individual GaAs-AlGaAs core-shell 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 4 K, we observe a ∼4× lower equivalent pump power for cw-excitation and a lower minimum lasing linewidth of ∼200 μeV, 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 ∼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 red-shifted lasing peak emission at high excitation levels.