Characterizing conical refraction optical tweezers

Craig McDonald (Lead / Corresponding author), Craig McDougall, Edik U. Rafailov, David McGloin

Research output: Contribution to journalArticlepeer-review

16 Citations (Scopus)


Conical refraction occurs when a beam of light travels through an appropriately cut biaxial crystal. By focussing 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, focussing 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
Original languageEnglish
Pages (from-to)6691-6694
Number of pages5
JournalOptics Letters
Issue number23
Early online date24 Oct 2014
Publication statusPublished - 2014


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