Photothermal trapping of dielectric particles by optical fiber-ring

The removal of dielectric particles and bacteria from water is an extremely important global issue, particularly, for drinking and sanitation. This work provides a demonstration of optical purification of water using an optical fiber-ring. The size of particles suspended in water for trapping is 2.08 mu m in diameter and the wavelength of light used for inducing photothermal effect is 1.55 mu m with a power of 97 mW. The fiber, 6 mu m in diameter, was formed to a racket-shaped ring with a minimum diameter of 167 mu m and a maximum one of 350 mu m. Experiment indicates that the particles moved toward the ring with the highest velocity of 4.2 mu m/s and are trapped/assembled in the center of the ring once the laser beam of 1.55-mu m wavelength was launched into the fiber. With a moving of the fiber-ring, the trapped/assembled particles were moved and the water can be purified by removal of the particles. (C)2011 Optical Society of America