An optical spin micromotor

Zong Ping Luo, Yu Long Sun, Kai Nan An

Research output: Contribution to journalArticlepeer-review

63 Scopus citations


An optical spin micromotor operated by optical tweezers, described in the present study, converts radiant energy directly to mechanical energy. This conversion is of great practical and fundamental interest. The optical spin micromotor consists of a two-bead linkage. The large bead (2.0 μmi in diameter) is trapped by the optical tweezers and rotates around the laser beam axis. The small bead (0.94 μm in diameter) is partially coated with gold/palladium for generating the spin torque through the change of momentum from gradient radiation pressure of the same laser applied on the coated small bead. With a laser power of 29 mW at the sample plane, the spin speed averaged 158.8 ± 155.5 rpm (mean±standard deviation) and the torque was estimated as 101.9±99.8 pN nm. This optical spin micromotor will be useful in (1) providing a fundamental step toward developing optical-operated mechanical devices, (2) twisting macromolecules, and (3) generating vortex and shear force in medium at nanoscale.

Original languageEnglish (US)
Pages (from-to)1779-1781
Number of pages3
JournalApplied Physics Letters
Issue number13
StatePublished - Mar 27 2000

ASJC Scopus subject areas

  • Physics and Astronomy (miscellaneous)


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