Microscopy with self-reconstructing beams

Although self-reconstructing beams have been the focus of many scientific studies over the past decade, hardly anything is known about their propagation and self-healing behaviour in a three-dimensional, inhomogeneous medium. The controlled reduction of scattering and beam spreading would enable a new illumination concept for light microscopes, particularly for those designed to look deep into scattering tissue. By investigating three different classes of refractive index inhomogeneity, using two large glass spheres, a cluster of smaller spheres and a piece of human skin, respectively, we show that beam self-reconstruction is indeed possible. We demonstrate that a Bessel beam is unexpectedly robust against deflection at objects, and we define measures for self-reconstruction in this context. We present a prototype of a microscope with self-reconstructing beams (MISERB) and show that a holographically shaped, scanned Bessel beam not only reduces scattering artefacts, but also simultaneously increases image quality and penetration depth in dense media.