Photoacoustically Generated Ultrasound for Light Guiding inside Transparent and Scattering Media

The guiding or focusing of light, crucial in many applications, often relies on bulky optical elements that are difficult to place in delicate mediums like biological tissue. Scattering further complicates the control of light within non-homogeneous media, restricting operating beyond 1 mm of depth. A promising solution involves shaped ultrasound to induce refractive index gradients within the tissue, acting as embedded lenses or waveguides. Our approach uses photoacoustic generation of pressure waves within the medium allowing light guiding without the geometrical constraints typical of transducers