Berlin 2015 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 24: Focus Session: Functional Semiconductor Nanowires II (organized by HL)

TT 24.1: Invited Talk

Monday, March 16, 2015, 15:00–15:30, EW 201

Light-matter interaction in wire cavities - from Purcell effect to Bose-Einstein condensates — •Rüdiger Schmidt-Grund — Universität Leipzig, Inst. für Exp. Physik II, Leipzig, Germany

I will discuss effects emerging in different regimes of light-matter interaction in, basically, ZnO-based nano- and micro-wire cavities of various type. The superior crystal quality along with very smooth surfaces of that self-organized structures allows for the observation of bosonic quantum effects like parametric mixing and multi-mode bosonic final state stimulation respective Bose-Einstein condensation (BEC), which in particular benefit from the rich mode structure of such cavities.

Depending on the photonic confinement strength lasing arises gained by electron-hole plasmas [1], from coherent photonic states fed by stimulated exciton-phonon scattering [2], and from BECs of exciton-polaritons [3]. Further, lateral conformal coating with concentric distributed Bragg reflector (DBR) shells prevents lateral losses and causes Purcell enhancement of the states lifetime in typical micropillar cavities [4]. The involved photonic modes are of one-dimensional Fabry-Perot and Whispering-Gallery type. In bare wires, usually modes of only one of these types can be observed. In DBR coated nano-wire cavities, both can coexist being at the same time in the strong and weak coupling regime with the electronic system.

[1] C. Czekalla et al, phys. stat. sol. b 247, 1282 (2010). [2] T. Michalsky et al, Appl. Phys. Lett. 105, 211106 (2014). [3] C.P. Dietrich et al, Phys. Rev. B: Rapid Comm. (2015). [4] T. Jakubczy et al, ACS Nano 8, 9970 (2014).