Tailored Light Fields
A Novel Approach for Complex Optical Traps
![Massgeschneiderte LichtfelderSetup](/imperia/md/content/physik_ap/denz/_v/forschen/ma__geschneiderte_lichtfelder_setup.jpg)
Nanostructuring of surfaces through chemical techniques or self-organization in the form of collective arrangements of molecules is already established. In addition to this collective organization also individual manipulation and selection gets more and more important for the functionalization and three dimensional structuring of matter, so that new approaches are needed. With our tailored light fields we develop a novel approach, which offers light modes for individual issues by a high degree of flexibility.
As a complementary approach to holographic optical tweezers, we calculate special, transverse complex light modes, which can be displayed on liquid crystal modulators. Such tailored light fields are employed by us for the optical manipulation of extended three dimensional structures, as they are characterized by transverse diversity as well as by defined propagation properties. Currently, we focus on light fields in elliptical geometries, as by the additional degree of freedom of ellipticity they offer both a wider range of beam shapes and the inclusion of radial and Cartesian geometries.
Mathieu Beams
![Me M4](/imperia/md/content/physik_ap/denz/_v/forschen/me_m4.jpg)
Non-diffracting light fields, whose elliptic solutions are given by Mathieu beams, are of particular interest for multi- dimensional micromanipulation. They are characterized by their seemingly divergence-free propagation, which allows to generate extensive three-dimensional structures. In cooperation with the University of Glasgow, we recently demonstrated the arrangement of elongated and spherical microparticles in three dimensions by non-diffracting Mathieu beams. As a special highlight, we were able to directly visualize the three-dimensional particle arrangement by the implementation of tailored light fields in a stereoscopic microscope. Since the so-generated structures indicate promising applications, especially the manipulation of functionalized or geometrically complex materials is of significance.
Ince-Gaussian Beams
Self-similar light fields are a second class of modes, which are well suited for optical micromanipulation. As opposed to non-diffracting light fields, they show divergence while their transverse amplitude and phase distribution remains preserved in the far field. Ince-Gaussian beams also represent solutions in elliptical coordinates, so that because of their diversity of modes, microparticles can be organized two- and three-dimensionally in different configurations. Additionally, they are suited for the investigation of light and matter interactions, which find interdisciplinary attention. Our results so far come across very positive response, showing the growing importance of this issue.
Ince-Gaussian beams – our novel concept in optical micromanipulation
Contact person: Christina Alpmann
References:
- Advanced optical trapping by complex beam shaping
M. Woerdemann, C. Alpmann, M, Esseling, C. Denz
accepted for publication, published first online as Laser & Photon. Rev., 2013, 1-16 PDF - Three-dimensional Particle Control by Holographic Optical Tweezers
M. Woerdemann, C. Alpmann, C. Denz
in "Optical Imaging and Metrology - Advanced Technologies" (2012)
Eds. W. Osten, N. Reingand
Wiley Verlag, ISBN-10: 3-527-41064-3 - Light Fields Can Tailor the Microscopic World
M. Woerdemann, C. Alpmann, C. Denz
Opt. Photonik 7, 2012, 47–52 PDF - Tailored light fields: Nondiffracting and self-similar beams for optical structuring and organization
C. Alpmann, M. Boguslawski, P. Rose, M. Wördemann, C. Denz
Proc. SPIE 8274, 2012, 82740R PDF - Tailored Light Fields: A Novel Approach for Creating Complex Optical Traps
C. Alpmann, M. Woerdemann and C. Denz
OPN 22 (Optics in 2011), 2011, 28 PDF - Optical assembly of micro particles into highly ordered structures using Ince-Gaussian beams
M. Woerdemann , C. Alpmann, C. Denz
Appl. Phys. Lett. 98, 2011, 111101 PDF - Mathieu beams as versatile light moulds for 3D micro particle assemblies
Christina Alpmann, Mike Woerdemann, Cornelia Denz.
Optics Express, Vol. 18, 2010, 26084-26091 PDF