Laser wavelength influence on capture and delivery of polystyrene microspheres using nanofibers

Abstract

In the paper we study the effects of laser wavelength on capture and delivery of polystyrene microspheres using a nanofiber. Theoretical analysis shows that when the fiber diameter and the power of the laser are fixed, with the increase of the laser wavelength, the range and intensity of evanescent wave outside optical fiber become large and light gradient and scattering forces exerted on spheres also increase, which means that the ability to capture and transportation of spheres using nanofiber increases with the laser wavelength. The experimental phenomena and theoretical predictions are completely consistent with each other, when the lasers with three wavelengths are separately injected into the fiber with a diameter of 600 nm, with the increase of the wavelength, the critical power becomes small, and when the laser power is constant, with the increase of the wavelength, velocities of spheres also increase, showing that the ability to capture and transport the microsheres is enhanced.