Article

Fluorescence imaging beyond the ballistic regime by ultrasound pulse guided digital phase conjugation

Howard Hughes Medical Institute, Janelia Farm Research Campus, 19700 Helix Drive, Ashburn, Virginia, 20147, USA.
Nature Photonics (Impact Factor: 29.96). 10/2012; 6(10):657-661. DOI: 10.1038/nphoton.2012.205
Source: PubMed

ABSTRACT Fluorescence imaging has revolutionized biomedical research over the past three decades. Its high molecular specificity and unrivaled single molecule level sensitivity have enabled breakthroughs in a variety of research fields. For in vivo applications, its major limitation is the superficial imaging depth as random scattering in biological tissues causes exponential attenuation of the ballistic component of a light wave. Here we present fluorescence imaging beyond the ballistic regime by combining single cycle pulsed ultrasound modulation and digital optical phase conjugation. We demonstrate a near isotropic 3D localized sound-light interaction zone. With the exceptionally high optical gain provided by the digital optical phase conjugation system, we can deliver sufficient optical power to a focus inside highly scattering media for not only fluorescence imaging but also a variety of linear and nonlinear spectroscopy measurements. This technology paves the way for many important applications in both fundamental biology research and clinical studies.

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Available from: Reto Fiolka, Apr 07, 2015
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    • "Although the requirement for a direct optical access to the target was considered as the main limitation for applying wavefront shaping in practical scenarios, several approaches to overcome this apparent limitation have been investigated. These methods include using implanted guide-stars [5] [6], ultrasonic tagging of light [7] [8] [9], and the photoacoustic effect [10]. "
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