Laser manipulation and fixation of metal nanoparticles using optical fiber probe

摘要

A laser manipulation technique for metal nanoparticles using an optical fiber has been developed. A micro ball lens adhered onto the flattened end of the optical fiber focuses a light beam propagated through a core. An object is trapped in the focused beam. An electromagnetic field distribution was numerically simulated for validation of the focusing lens. Calculation including an Au nanoparticle indicated that the laser trapping would be possible with this method. In the experiment, trapping of Au particles with diameter of 200nm was achieved by using a light source (Nd-YAG: 1064nm). The maximum trapping efficiency attained in the focal region was estimated to be 5.4fN/mW. Additionally, the fixation of a manipulated particle onto a glass substrate was also demonstrated. With intensifying the laser power, a laser-trapped particle is fixed on the substrate. By repetition of the procedure of laser manipulation and fixation, alignment of Au nanoparticles was achieved.