Near-field optical tweezers based on micron tapered fiber

The evanescent field intensity distribution of the fiber was analyzed both theoretically and experimentally(z=10nm,100nm,500nm,1 000nm),and the manipulation of micron fiber optical tweezers for microspheres was studied in experiment.In the experiment,a singlemode optical fiber with a diameter of 125μm was transformed into a tapered fiber with a 2μm diameter at the minimum waist.When the laser light was launched into the fiber,due to the evanescent field of the tapered fiber,the polystyrene microspheres with a diameter of 3μm could keep balanced state,and the nearby microspheres were attracted onto the fiber surface and rolled at the speed of 5.3μm/s in the direction of light propagation.This experiment traps the microspheres and verifies the mechanical effect of the fiber optical tweezers.The non-contact,non-destructive manipulation of fiber optical tweezers for microspheres has potential applications in the field of biosensors.