Optical trapping of sub-10nm particles using plasmonic coaxial apertures

Stanford researchers have designed a powerful plasmonic coaxial aperture as a low-power optical trap for nanosized specimens, a regime that is inaccessible with the other designs. This device can stably trap dielectric particles smaller than 10 nm in diameter while keeping the trapping power level below 100 mW. By tapering the thickness of the coaxial dielectric channel, trapping can be extended to sub-2 nm particles. This design constrains particles at the surface of the aperture rather than inside, and allows further particle manipulation and processing. Such capability enables trapping and manipulation of single proteins such as enzymes, and possibly molecules as small as glucose.

Stage of Research

Inventors demonstrated that coaxial apertures with a 25 nm silica channel can trap particles as small as 5 nm while keeping the required power well below 100 mW. They have also designed an aperture that can trap specific chiral molecules.