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Welcome to the Bio- and Nano-Photonics research group

Head of the Laboratory


       Prof. Dr. Alexander Rohrbach

Email: rohrbach(at)imtek.de

University of Freiburg
Department of Microsystems Engineering - IMTEK
Laboratory for Bio- and Nano-Photonics
Georges-Köhler-Allee 102
79110 Freiburg
TEL. ++49 761 203 7536
TEL. ++49 761 203 7548 (secretary)


Research goals

Living cells are fascinating microsystems. Therefore we develop novel techniques for laser optical microscopy and optical force based applications, to investigate the biophysics of living cells and of bio-mimetic systems based on their nano-mechanics and thermal fluctuations.


Our research group

Please click on the picture to see our group taking off due to non-conservative forces...


Selected Publications

L. Friedrich, A. Rohrbach
Surface imaging beyond the diffraction limit with optically trapped spheres
Nature Nanotechnology 2015, issue 10, pages 1064–1069

M. Koch, A. Rohrbach
Object adapted optical trapping and shape tracking of energy switching helical bacteria
Nature Photonics 2012, issue 6, pages 680 - 686

F. Fahrbach, A. Rohrbach
Propagation stability of self-reconstructing Bessel beams enables contrast-enhanced imaging in thick media
Nature Communications 2012, issue 3, page 632

F. Fahrbach, P. Simon, A. Rohrbach
Microscopy with self-reconstructing beams
Nature Photonics 2010 , issue 4, pages 780 - 785

H. Kress, E. H. K. Stelzer, D. Holzer, F. Buss, G. Griffiths, A. Rohrbach
Filopodia act as phagocytic tentacles and pull with discrete steps and a load-dependent velocity
PNAS 2007, issue 104, pages 11633 - 11638

A. Rohrbach
Stiffness of optical traps: Quantitative agreement between experiment and electromagnetic theory
PRL 2005, issue 95, pages 168102



New publication by Mathias Koch in Nature Scientific Reports "Single microtubules and small networks become significantly stiffer on short time-scales upon mechanical stimulation" ( >>> download pdf)

A. Rohrbach rejects call from other university and accepts stay offer from the University of Freiburg

New publication by Tobias Meinert in Nature Scientific Reports "Separation of ballistic and diffusive fluorescence photons in confocal Light-Sheet Microscopy of Arabidopsis roots" ( >>> download pdf)

New publication by Felix Jünger in Nature Scientific Reports "Fast, label-free super-resolution live-cell imaging using rotating coherent scattering (ROCS) microscopy" ( >>> download pdf)

New publication by Cristian Gohn-Kreuz in Optics Express "Light-sheet generation in inhomogeneous media using self-reconstructing beams and the STED-principle" ( >>> download pdf)

New publication by Benjamin Tränkle in Soft Matter "Interaction dynamics of two diffusing particles: contact times and influence of nearby surfaces" ( >>> download pdf)

New publication by Marc Blattmann in Nano Letters "Plasmonic Coupling Dynamics of Silver Nanoparticles in an Optical Trap" ( >>> download pdf)

Luis Köbele starts as a new PhD student in our lab.

New publication by Lars Friedrich in Nature Nanotechnology "Surface imaging beyond the diffraction limit with optically trapped spheres" ( >>> download pdf)

New publication by Felix Jünger in Biophysical Journal "Measuring local viscosities near membranes of living cells with photonic force microscopy" ( >>> download pdf)

Nicolas Schudell starts as a new PhD student in our lab.

Moritz Michelbach starts as a new bachelor student in our lab.

New publication by Felix Kohler in Biophysical Journal "Surfing along filopodia a particle transport revealed by molecular-scale fluctuation analyses" ( >>> download pdf)

Matthias Koch defends his PhD thesis successfully. Congrats, Dr. Koch!

New publication by Felix Kohler in Physical Review E: "Synchronization of elastically coupled processive molecular motors and regulation of cargo transport" ( >>> download pdf)

Yi Wei starts as a new bachelor student in our lab.

New publication by Matthias Koch in Optics Express: "How to calibrate an object-adapted optical trap for force sensing and interferometric shape tracking of asymmetric structures" ( >>> download pdf)

Iris Kuntz starts as a new diploma student in our lab.

Julian Roth starts as a new phd student in our lab.

New publication by Andreas Meinel in Soft Matter: "Induced phagocytic particle uptake into a giant unilamellar vesicle" ( >>> download pdf)

New publication by Markus Grießhammer in Optics Express: "5D-Tracking of a nanorod in a focused laser beam - a theoretical concept" ( >>> download pdf)

Dominic Ruh starts as PostDoc in our lab.

Rebecca Michiels starts as a new PhD student in our lab.

Benjamin Tränkle successfully defended his PhD thesis on "Interaktionsdynamik kolloidaler Partikel in beschränkten Volumina".

New publication by Philipp von Olshausen in Optics Letters: "Coherent total internal reflection dark-field microscopy: label-free imaging beyond the diffraction limit" ( >>> download pdf)

New publication by Philipp von Olshausen in Biophysical Journal: "Superresolution Imaging of Dynamic MreB Filaments in B. subtilis - A Multiple-Motor-Driven Transport?" ( >>> download pdf)

New publication by Hoda Moosavi in Applied Optics: "Feedback phase correction of Bessel beams in confocal line light-sheet microscopy: a simulation study" ( >>> download pdf)

Markus Grießhammer successfully defended his PhD thesis on "Interferometrisches Tracking und Manipulation von Nanorods mit optischen Pinzetten"

New publication by Fahrbach et al. in Optics Express: "Light-sheet microscopy in thick media using scanned Bessel beams and two-photon fluorescence excitation" ( >>> download pdf)

New publication by Fahrbach et al. in Optics Express: "Self-reconstructing sectioned Bessel beams offer submicron optical sectioning for large fields of view in light-sheet microscopy" ( >>> download pdf)

Tobias Meinert starts as a new PhD student in our group.

Felix Kohler successfully defended his PhD thesis on "Photonic force based investigations of filopodial dynamics and coupled molecular motors"


Keywords / Schlüsselwörter

Optics, Photonics, Biophysics, optical traps, optical tweezers, particle tracking, microscopy, light-sheet, self-reconstructing beams, Bessel beams, light propagation, BPM, scattering, superresolution, TIRF, fluorescence, STED, hydrodynamic coupling, fluctuation, diffusion, molecular motors, mechanics of the cytoskeleton, visco-elastic theory, phagocytes, filopodia, bacteria, cell wall, vesicles

Optik, Photonik, Biophysik, optische Fallen, optische Pinzetten, Partikeltracking, Mikroskopie, Lichtscheibe, selbstrekonstruierende Strahlen, Bessel-Strahlen, Lichtpropagation, BPM, Streuung, Superauflösung, TIRF, Fluoreszenz, STED, hydrodynamische Kopplung, Fluktuation, Diffusion, molekulare Motoren, Zytoskelett-Mechanik, Visko-elastische Theorie, Fresszellen, Filopodien, Bakterien, Zellwand, Vesikel

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