Nanoscale optical trap for fluorescent nanoparticles

Optical trapping has offered new potentialities in the manipulation of bacteria, living cells, organelles, or microparticles in micrometric volumes. Its extension to the nanometer scale may create exceptional opportunities in many areas of science. We report here the trapping of a single 100 nm radius particle in a nanometric volume. The trapping relies on stimulated emission of the fluorescent particle in the evanescent wave of a totally reflected Arago spot on a glass-liquid interface. The trapping volume is a 200 nm height and 125 nm radius cylinder. Such a nano-trap, aside from applications in nano-physics, may echo the needs of life scientists to manipulate ever-smaller biological samples.