Photoacoustically guided wavefront shaping for enhanced optical focusing in scattering media

Research output: Journal Publications and ReviewsRGC 21 - Publication in refereed journalpeer-review

261 Scopus Citations
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Author(s)

Detail(s)

Original languageEnglish
Pages (from-to)126-132
Journal / PublicationNature Photonics
Volume9
Issue number2
Online published19 Jan 2015
Publication statusPublished - Feb 2015
Externally publishedYes

Abstract

Non-invasively focusing light into strongly scattering media, such as biological tissue, is highly desirable but challenging. Recently, ultrasonically guided wavefront-shaping technologies have been developed to address this limitation. So far, the focusing resolution of most implementations has been limited by acoustic diffraction. Here, we introduce nonlinear photoacoustically guided wavefront shaping (PAWS), which achieves optical diffraction-limited focusing in scattering media. We develop an efficient dual-pulse excitation approach to generate strong nonlinear photoacoustic signals based on the Grueneisen relaxation effect. These nonlinear photoacoustic signals are used as feedback to guide iterative wavefront optimization. As a result, light is effectively focused to a single optical speckle grain on the scale of 5-7Î 1/4m, which is ~10 times smaller than the acoustic focus, with an enhancement factor of ~6,000 in peak fluence. This technology has the potential to benefit many applications that require a highly confined strong optical focus in tissue.

Citation Format(s)

Photoacoustically guided wavefront shaping for enhanced optical focusing in scattering media. / Lai, Puxiang; Wang, Lidai; Tay, Jian Wei et al.
In: Nature Photonics, Vol. 9, No. 2, 02.2015, p. 126-132.

Research output: Journal Publications and ReviewsRGC 21 - Publication in refereed journalpeer-review