Martin Šiler, Pavel Zemánek
Single beam optical tweezers hold particles behind the focal plane due to the high gradients of optical intensity present in a focused laser beam. However, description of this optical field based on a vectorial theory of diffraction reveals that the high intensity focal area is accompanied by several secondary maxima on the optical axis as well as by a structure of rings away of the optical axis. Such a structure can be found in beams exhibiting spherical aberrations as well as in beams where aberration is corrected. Here, we discuss possibility to use these secondary maxima of aberration-corrected beams as the optical traps. We present the properties of such traps created by objective lenses of various numerical apertures that are focusing plane waves.
DOI
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