Snapshot coherence-gated direct wavefront sensing for multi-photon microscopy

Journal article (2014)
Department
Delft Center for Systems and Control (Mechanical, Maritime and Materials Engineering) (TU Delft)
Copyright: © 2014 Optical Society of America
DOI: https://doi.org/doi:10.1364/OE.22.009715
Active or adaptive optics Imaging through turbid media Nonlinear microscopy Aberrations Tissue characterization Index measurements
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Published Date

15-04-2014

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Source:

Optics Express, 22 (8), 2014

ISSN:

1094-4087

Source:

http://www.opticsinfobase.org/oe/abstract.cfm?URI=oe-22-8-9715

Faculty

Mechanical, Maritime and Materials Engineering

Department

Delft Center for Systems and Control

Abstract

Deep imaging in turbid media such as biological tissue is challenging due to scattering and optical aberrations. Adaptive optics has the potential to compensate the tissue aberrations. We present a wavefront sensing scheme for multi-photon scanning microscopes using the pulsed, near-infrared light reflected back from the sample utilising coherence gating and a confocal pinhole to isolate the light from a layer of interest. By interfering the back-reflected light with a tilted reference beam, we create a fringe pattern with a known spatial carrier frequency in an image of the back-aperture plane of the microscope objective. The wavefront aberrations distort this fringe pattern and thereby imprint themselves at the carrier frequency, which allows us to separate the aberrations in the Fourier domain from low spatial frequency noise. A Fourier analysis of the modulated fringes combined with a virtual Shack-Hartmann sensor for smoothing yields a modal representation of the wavefront suitable for correction. We show results with this method correcting both DM-induced and sample-induced aberrations in rat tail collagen fibres as well as a Hoechst-stained MCF-7 spheroid of cancer cells.