4. A spatial phase modulator shapes the wavefront of the incident light before it reaches the opaque object. The wavefront generated by the phase modulator is designed to perfectly match the scattering sample, like a key matches a lock.

5. Inside the sample, light is scattered hundreds of times. However, for this very special wavefront, scattering now makes that the transmitted light is in phase. The light leaves the object as a focused laser beam.

6. The opaque object now acts as a lens! The sharp focus was measured to be a thousand times more intense than the diffuse transmission.

I.M. Vellekoop and A.P. Mosk
Focusing coherent light through opaque strongly scattering media
Opt. Lett. 32, 2309-2311 (2007) (pdf 392 kb)

This work is part of the research program of the "Stichting voor Fundamenteel Onderzoek der Materie (FOM)", which is financially supported by the "Nederlandse Organisatie voor Wetenschappelijk Onderzoek NWO"

The animation is created by Edwin van der Pol

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