Self-imaged optical bottle beam based optical tweezers systems

Abstract

Optical tweezers technique has aggrandized the light-matter interaction, whereby researchers have employed light forces from colloidal sciences to biomedical applications. There have been constant quests to integrate novel beams in tweezers system for myriads of novel applications. In this paper, we report optical tweezers system based on self-imaged optical bottle beams, which has some distinct advantages over other conventional beams like Gaussian, Laguerre-Gaussian and Bessel beams in few applications. A self-imaged bottle beam is obtained by superimposing two Bessel beams with varying radial wavevectors. A self-imaged bottle beam possesses three-dimensional intensity-null points along the propagation axis and by varying the radial wavevectors of the Bessel beams number of bottles; location of bottles and the dimension of the bottles can be pre-determined. Moreover, by dynamically varying the parameters of radial wavevector of interfering Bessel beams, the dynamic potential-well obtained are capable of transporting both high and low indices microparticle in conveyor-belt arrangement along the longitudinal axis. Bottle beams belongs to the family of propagation-invariant beams and hence inherent the propagation-invariance and self-reconstruction properties of Bessel beam together with three-dimensional trapping potential contrary to Bessel beam whereby the particles trapped in the central core are loosing defined in the longitudinal axis. Such bottle beams also holds promise applications in blue-detuned optical taps for the optical confinement of laser-cooled atoms in three-dimensional dark region.