Aberration correction for real-time measurements in adaptive confocal microscope
Microscopic techniques with high spatial and temporal resolution are required
for measuring biological cells and tissues. Confocal microscopy is an established
technique, which is based on a pinhole detection that introduces optical sectioning
abilities. The usage of microscope objectives with high numerical aperture allows
achieving high spatial resolution, but simultaneously increases the impact
of systematic aberrations. These aberrations add to sample induced aberrations
and limit the achievable resolution of a confocal microscope. Aberrations can be
addressed by using adaptive optical elements. Furthermore adaptive elements
allow for fast scanning. In the preparatory work we successfully verified, that two
adaptive lenses, one in the illumination and the second in the detection path, allow
for the first time, to create axial scans with homogeneous axial resolution
over the whole depth-range. The aim of the proposal is to create a fully-adaptive
confocal microscope, which enables both fast scanning and high spatial resolution
due to aberration correction. For this purpose novel adaptive lenses with integrated
aberration correction will be developed and used to create the axial
scanning. These lenses enable to compensate for both symmetric (spherical, defocus)
und asymmetric (astigmatism, coma)-aberrations our confocal microscope.
Integrated pressure sensors allow controlling the focal length of the adaptive
lens. For lateral scanning adaptive prisms are used, which promise to create
fast lateral scans with less aberrations and compact setup. Using the novel adaptive
devices opens up the possibility to miniaturize the confocal setup and to create
a compact and hand-held microscope. As a first test paradigm, the new confocal
microscope will be used to identify thyroid gland disruptors in Zebrafish embryos.
Staff: K. Philipp
Period: 03/15 - 03/19
Partner: Universität Freiburg, Prof. Wallrabe; UFZ Leibzig, Dr. Stefan Scholz
Fluoreszenzaufnahmen der Schilddrüse von transgenen Zebrabärblingsembryonen ohne (a) und mit (b) Korrektur sphärischer Aberrationen. Aufnahme des gesamten Embryos, Dimensionen sind ca (1.5x5) mm2 (c). Intensitätsprofile entlang spezifischer Zeilen (d). Die Aufnahmen erfolgten 110 Stunden nach der Befruchtung.
K. Philipp, A. Smolarski, N. Koukourakis, A. Fischer, M. Stürmer, U. Wallrabe, J. Czarske “Volumetric HiLo microscopy employing an electrically tunable lens”, Opt. Express 24(13), 15029-15041 (2016).
K. Philipp, F. Lemke, S. Scholz, U. Wallrabe, M. C. Wapler, N. Koukourakis, J. W. Czarske. "Diffraction-limited axial scanning in thick biological tissue employing an aberration
correcting adaptive lens." arXiv preprint arXiv:1811.11457 (2018).