Trojak, Oliver and Woodhead, Christopher Stephen and Park, Suk-In and Dong Song, Jin and Young, Robert James and Sapienza, Luca (2018) Combined metallic nano-rings and solid-immersion lenses for bright emission from single InAs/GaAs quantum dots. Applied Physics Letters, 112: 221102. 221102-1-221102-4. ISSN 0003-6951
1801.07210.pdf - Accepted Version
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Abstract
Solid-state single-photon emitters are key components for integrated quantum photonic devices. However, they can suffer from poor extraction efficiencies, caused by the large refractive index contrast between the bulk material they are embedded in and air: this results in a small fraction (that can be as low as ﰀ0.1%) of the emitted photons reaching free-space collection optics. To overcome this issue, we present a device that combines a metallic nano-ring, positioned on the sam- ple surface and centered around the emitter, and an epoxy-based super-solid immersion lens, depos- ited above the ring devices. We show that the combined broadband lensing effect of the nano-ring and the super-solid immersion lens significantly increases the extraction of light emitted by single InAs/GaAs quantum dots into free space: we observe cumulative enhancements that allow us to estimate photon fluxes on the first collecting lens approaching 106 counts per second, from a single quantum dot in bulk. The combined broad-band enhancement in the extraction of light can be implemented with any kind of classical and quantum solid-state emitter and opens the path to the realisation of scalable bright devices. The same approach can also be implemented to improve the absorption of light, for instance, for small-area broadband photo-detectors.