@article {5101,
	title = {Fluorescence imaging beyond the ballistic regime by ultrasound-pulse-guided digital phase conjugation.},
	journal = {Nature Photonics},
	volume = {6},
	year = {2012},
	month = {2012 Aug},
	pages = {657},
	abstract = {<p>Fluorescence imaging has revolutionized biomedical research over the past three decades. Its high molecular specificity and unrivalled single-molecule-level sensitivity have enabled breakthroughs in a number of research fields. For in vivo applications its major limitation is its superficial imaging depth, a result of random scattering in biological tissues causing 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 three-dimensional localized sound{\textendash}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.</p>
},
	doi = {doi:10.1038/nphoton.2012.205},
	author = {Si, Ke and Fiolka, Reto and Cui, Meng}
}
