Nanometric laser trapping of microbubbles based on nanostructured substrates

Laser trapping near the surface of a nanostructured substrate is demonstrated. Stable microbubbles with radii of 1–20 μm have been created and manipulated with sub-micron precision by a focused laser beam in an immersion oil covering arrays of pairs of gold nanopillars deposited on a glass substrate. The threshold for bubble creation and trapping characteristics depended on near-field coupling of nanopillars. The nanometric laser tweezers showed giant trapping efficiency of Q ∼ 50 for the trapped microbubbles.