Realization of pitch-rotational torque wrench in two-beam optical tweezers. (26th November 2021)

• Record Type: Journal Article
• Authors: Lokesh, Muruga; Vaippully, Rahul; Bhallamudi, Vidya P; Prabhakar, Anil; Roy, Basudev
• Is Part Of: Journal of physics communications. Volume 5:Number 11(2021)
• Publication Date: 2021-11-26
• Subjects: optical tweezers -- pitch rotation -- pitch rotational torque wrench; Physics -- Periodicals; 530.05
• DOI: 10.1088/2399-6528/ac3a96
• Languages: English
• ISSNs: 2399-6528

Abstract

Abstract: 3D Pitch (out-of-plane) rotational motion has been generated in spherical particles by maneuvering the laser spots of holographic optical tweezers. However, since the spherical particles, which are required to minimise drag are perfectly isotropic, a controllable torque cannot be applied with it. It remains free to spin about any axis even after moving the tweezers beams. It is here that we trap birefringent particles of about 3 μ m diameter in two tweezers beams and then change the depth of one of the beam foci controllably to generate a pitch rotational torque-wrench and avoid the free spinning of the particle. We also detect the rotation with newly developed pitch motion detection technique and apply controlled torques on the particle.