Ultrasound light waveguiding to increase fluorescence of a hidden target

Detection, imaging and treatment of targets in deep tissues are severely limited by extremely small amount of light reaching them, with most losses due to light scattering in tissues. Ultrasound light waveguiding has been recently demonstrated as a promising technique to counteract scattering and increase the amount of light available at depth by recollecting scattered photons and guiding them further. Here we use this technique to increase the intensity of fluorescence, collected from a target hidden behind a 3 mm thick scattering phantom. Ultrasound light waveguide is set up in a phantom using a common linear array transducer arranged transversally to the light beam, and fluorescence is measured in transmission. We use a pulsed 532 nm light as an excitation source common for photoacoustic imaging and demonstrate ultrasound light waveguiding induced increase of detected fluorescence.