Optimization of an object shape to achieve extremal axial optical force in a standing wave

0335079 - ÚPT 2010 RIV US eng C - Konferenční příspěvek (zahraniční konf.)
Trojek, Jan - Karásek, Vítězslav - Zemánek, Pavel
Optimization of an object shape to achieve extremal axial optical force in a standing wave.
Optical Trapping and Optical Micromanipulation VI. (Proceedings of SPIE Vol. 7400). Bellingham: SPIE, 2009, 74000L: 1-11. ISBN 978-0-8194-7690-6. ISSN 0277-786X.
[Optical Trapping and Optical Micromanipulation /6./. San Diego (US), 02.08.2009-06.08.2009]
Grant CEP: GA MŠMT(CZ) LC06007; GA MŠMT OC08034
Výzkumný záměr: CEZ:AV0Z20650511
Klíčová slova: optical force * nonspherical objects * analytical calculations * numerical computations * coupled dipole method
Kód oboru RIV: BH - Optika, masery a lasery

We consider prolate objects of cylindrical symmetry with radius periodically modulated along the axial direction and we present a theoretical study of optimized objects shapes resulting in up to tenfold enhancement of the axial optical force in comparison with the original unmodulated object shape. We obtain analytical formulas for the axial optical force acting on low refractive index objects where the light scattering by the object is negligible. Numerical results based on the coupled dipole method support the previous simplified analytical conclusions and they are also presented for objects with higher refractive indices. The objects are trapped in a standing wave, that offers many useful advantages in comparison to single beam trapping, especially for submicrometer size particles. It provides axial force stronger by several orders of magnitude, much higher axial trap stiffness, and spatial confinement of particles with higher refractive index.
Trvalý link: http://hdl.handle.net/11104/0179652