Coherent optical imaging through opaque layers

Scattering of light is usually seen as a nuisance in microscopy. Scattering limits the penetration depth and strongly deteriorates the achievable resolution. However, by gaining active spatial control over the optical wave front it is possible to manipulate the propagation of scattered light even far in the multiple scattering regime.[1–3] It was recently shown that in this way scattered light can even be exploited for perfect optical focussing.[4] These wave front shaping techniques pave the way for new microscopy methods based on strong light scattering.[5–8]