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arXiv · 2208.06453

Observation of large spontaneous emission rate enhancement of quantum dots in a broken-symmetry slow-light waveguide

Hamidreza Siampour·Christopher O'Rourke·Alistair J. Brash·Maxim N. Makhonin·René Dost·Dominic J. Hallett·Edmund Clarke·Pallavi K. Patil·Maurice S. Skolnick·A. Mark Fox
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Abstract

Quantum states of light and matter can be manipulated on the nanoscale to provide a technological resource for aiding the implementation of scalable photonic quantum technologies [1-3]. Experimental progress relies on the quality and efficiency of the coupling between photons and internal states of quantum emitters [4-6]. Here we demonstrate a nanophotonic waveguide platform with embedded quantum dots (QDs) that enables both Purcell-enhanced emission and strong chiral coupling. The design uses slow-light effects in a glide-plane photonic crystal waveguide with QD tuning to match the emission frequency to the slow-light region. Simulations were used to map the chirality and Purcell enhancement depending on the position of a dipole emitter relative to the air holes. The highest Purcell factors and chirality occur in separate regions, but there is still a significant area where high values of both can be obtained. Based on this, we first demonstrate a record large radiative decay rate of 17 ns^-1 (60 ps lifetime) corresponding to a 20 fold Purcell enhancement. This was achieved by electric-field tuning of the QD to the slow-light region and quasi-resonant phonon-sideband excitation. We then demonstrate a 5 fold Purcell enhancement for a dot with high degree of chiral coupling to waveguide modes, substantially surpassing all previous measurements. Together these demonstrate the excellent prospects for using QDs in scalable implementations of on-chip spin-photonics relying on chiral quantum optics.

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Hamidreza Siampour, Christopher O'Rourke, Alistair J. Brash, Maxim N. Makhonin, René Dost, Dominic J. Hallett, Edmund Clarke, Pallavi K. Patil, Maurice S. Skolnick, A. Mark Fox. 2022-08-12. Observation of large spontaneous emission rate enhancement of quantum dots in a broken-symmetry slow-light waveguide. https://doi.org/10.1038/s41534-023-00686-9

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