Optical manipulation of particles of all shapes and sizes (Vol. 46 No. 2)

Ellipsoidal particle levitating at the optical beam waist, with its long axis aligned to the beam axis. Credit: B. M. Mihiretie et al.

A new study of how particles may respond to the mechanical effects of light helps improve optical manipulation and remote sensing of non-spherical particles.

Manipulation of small objects by light has gained in popularity in the past few years. Now, scientists have performed the first systematic analysis of the behaviour of ellipsoidal particles manipulated by laser beams. The work shows that such particles are constantly moving in and out of the reach of an optical beam, creating oscillations. These findings have been obtained by the authors. This work could help understand the unusual behaviour of rod-like particles manipulated by optical tweezers. Ultimately, the theoretical part of this work could contribute numerical models of how complicated shapes and large sizes scatter laser light. Numerous applications exist in fluid engineering and remote sensing methods.

B. M. Mihiretie, P.Snabre, J.-C. Loudet and B. Pouligny, "Optically driven oscillations of ellipsoid particles. Part I: Experimental observations", Eur. Phys. J. E 37, 124 (2014)

J.C. Loudet, B. M. Mihiretie and B. Pouligny, "Optically driven oscillations of ellipsoidal particles. Part II: Ray-Optics calculations", Eur. Phys. J. E 37, 125 (2014)