RESUMO
Single-photon sources are required for quantum technologies and can be created from individual atoms and atom-like defects. Erbium ions produce single photons at low-loss fiber optic wavelengths, but they have low emission rates, making them challenging to isolate reliably. Here, we tune the size of gold double nanoholes (DNHs) to enhance the emission of single erbium emitters, achieving 50× enhancement over rectangular apertures previously demonstrated. This produces enough enhancement to show emission from single nanocrystals at wavelengths not seen in our previous work, i.e., 400 and 1550 nm. We observe discrete levels of emission for nanocrystals with low numbers of emitters and demonstrate isolating single emitters. We describe how the trapping time is proportional to the enhancement factor for a given DNH structure, giving us an independent way to measure the enhancement. This shows a promising path to achieving single emitter sources at 1550 nm.
RESUMO
Double-nanoholes fabricated by colloidal lithography were used for trapping single colloidal particles and single proteins. A gap separation of 60 nm between the cusps of the double-nanohole was achieved in a gold film of 70 nm thickness sputter coated onglass. The cusp separation was reduced steadily down to 10 nm by plasma etching the colloidal particles prior to sputter coating. Scanning electron microscopy was used to locate a particular double-nanohole and it was registered for later microscopy experiments. 30 nm polystyrene particles, the rubisco protein and bovine serum albumin were trapped using a laser focused through the aperture. Compared to other methods that require top-down nanofabrication, this approach is inexpensive and produces high-quality samples.
