Single-nanoparticle detection with slot-mode photonic crystal cavities


Wang C, Quan Q, Kita S, Li Y, Loncar M. Single-nanoparticle detection with slot-mode photonic crystal cavities [Internet]. Appl. Phys. Lett. 2015;106:261105.
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Optical cavities that are capable for detecting single nanoparticles could lead to great progress in early stage disease diagnostics and the study of biological interactions on the single-molecule level. In particular, photonic crystal (PhC) cavities are excellent platforms for label-free single-nanoparticle detection, owing to their high quality (Q) factors and wavelength-scale modal volumes. Here, we demonstrate the design and fabrication of a high-Q (>104) slot-mode PhC nanobeam cavity, which is able to strongly confine light in the slotted regions. The enhanced light-matter interaction results in an order of magnitude improvement in both refractive index sensitivity (439 nm/RIU) and single-nanoparticle sensitivity compared with conventional dielectric-mode PhC cavities. Detection of single polystyrene nanoparticles with radii of 20 nm and 30 nm is demonstrated in aqueous environments (DO), without additional laser and temperature stabilization techniques.

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Last updated on 10/30/2015