Dynamic size tuning of multidimensional optically bound matter

0388101 - ÚPT 2013 RIV US eng C - Conference Paper (international conference)
Brzobohatý, Oto - Karásek, Vítězslav - Šiler, Martin - Zemánek, Pavel
Dynamic size tuning of multidimensional optically bound matter.
CPS 2012. 18th Czech-Polish-Slovak Optical Conference on Wave and Quantum Aspects of Contemporary Optics (Proceedings of SPIE Vol.8697). Bellingham: SPIE, 2012, 86970U: 1-10. ISBN 978-0-8194-9481-8.
[CPS 2012. Czech-Polish-Slovak Optical Conference on Wave and Quantum Aspects of Contemporary Optics /18./. Ostravice (CZ), 03.09.2012-07.09.2012]
R&D Projects: GA ČR GA202/09/0348; GA ČR GPP205/11/P294; GA MŠMT ED0017/01/01
Institutional support: RVO:68081731
Keywords : optical binding * optical tweezers * dual-beam trap * self-arrangement * colloids
Subject RIV: BH - Optics, Masers, Lasers

Optical binding presents an original method for self- arrangement of solid microparticles in liquid or air. The resulting equilibrium positions of the particles in an optically bound structure (OBS) are not only influenced by the spatial intensity profiles of the incident laser beams but also by the light scattered from all the bound particles. The inter-particle distances in OBSs can be externally modified by changing the refractive index of the medium or the spatial intensity distribution of the beams. Especially the last option is now well developed due to the technology of spatial light modulators (SLM). We utilized this tool to generate OBSs in counterpropagating laser beams having various spatial intensity profiles. In contrast to the previous methods, where OBSs were kept stationary without dynamic control, we modified dynamically the optical cage for self-arranged particles which led to enlargement or shrinking of the OBS. Using elaborate optical fields suitable for particular cases we demonstrated the size tunability of OBSs that were self-arranged along one, two or three dimensions. Compressing of the optical cage below a certain limit led to a collapse of the self-arranged micro-structures, thus indicating a phase transitions in such colloidal structures. Within a system of counter-propagating optical vortices we observed transfer of angular momentum of light to two-dimensional OBSs, revolving around the intrinsic on-axis phase singularity of the trapping beams.
Permanent Link: http://hdl.handle.net/11104/0217009