Single-beam trapping using laser beams focused by low and high numerical apertures: angular spectrum approach

0434439 - ÚPT 2015 RIV US eng C - Conference Paper (international conference)
Šiler, Martin - Brzobohatý, Oto - Jákl, Petr - Karásek, Vítězslav - Zemánek, Pavel
Single-beam trapping using laser beams focused by low and high numerical apertures: angular spectrum approach.
Complex Light and Optical Forces VIII. (Proceedings of SPIE 8999). Bellingham: SPIE, 2014, 899904:1-8. ISBN 9780819499127. ISSN 0277-786X.
[Complex Light and Optical Forces /8./. San Francisco (US), 04.02.2014-06.02.2014]
R&D Projects: GA ČR GPP205/12/P868; GA MŠMT ED0017/01/01; GA MŠMT EE2.4.31.0016; GA MŠMT(CZ) LO1212
Institutional support: RVO:68081731
Keywords : optical tweezers * optical force calculation * focused beam * angular spectrum * multiple trapping locations
Subject RIV: BH - Optics, Masers, Lasers

Single beam optical tweezers hold particles behind the focal plane due to the highly focused laser beam. However, even moderately focused beams may stably confine particles of high refractive index contrast and sizes up to half wavelength. This is caused by the fact that the light structure near focus is complex even for such moderately focused beams. The intensity profile consists of several axial oscillations as well as off-axis lobes or rings which enhance trapping. Moreover, side lobes provide another multiple trapping sites for small sized particles. The properties of these traps will be analyzed theoretically by means of Generalized Lorenz-Mie Scattering theory.
Permanent Link: http://hdl.handle.net/11104/0238500