title: Characterizing conical refraction optical tweezers.
abstract: Conical refraction occurs when a beam of light travels through an appropriately cut biaxial crystal. By focusing the conically refracted beam through a high numerical aperture microscope objective, conical refraction optical tweezers can be created, allowing for particle manipulation in both Raman spots, and in the Lloyd/Poggendorff rings. We present a thorough quantification of the trapping properties of such a beam, focusing on the trap stiffness, and how this varies with trap power and trapped particle location. We show that the lower Raman spot can be thought of as a single-beam optical gradient force trap, while radiation pressure dominates in the upper Raman spot, leading to optical levitation rather than trapping. Particles in the Lloyd/Poggendorff rings experience a lower trap stiffness than particles in the lower Raman spot, but benefit from rotational control.
authors.forename: C
authors.initials: C
authors.lastname: McDonald
authors.forename: C
authors.initials: C
authors.lastname: McDougall
authors.forename: E
authors.initials: E
authors.lastname: Rafailov
authors.forename: D
authors.initials: D
authors.lastname: McGloin