Adaptive quantum optics

Could photons, light particles, really condense and how will this ‘liquid light’ behave then? Condensed light is an example of a ‘Bose-Einstein condensate’: the theory has been there for 100 years, but University of Twente researchers now demonstrate the effect even at room temperature. For this, they created a microsize mirror with channels in which photons actually ‘flow’ like a liquid. In these channels, the photons try to stay together as group by choosing the path that leads to the lowest losses and thus, in a way, demonstrate ‘social behaviour’. The results are published in Nature Communications.

Twente researchers have -in cooperation with scientists from ARCNL- investigated the imaging capacities of special kind of optical fibers with a round core.

AQO researchers Matthijs Velsink and Pepijn Pinkse together with Lyuba Amitonova from ARCNL & VU published a new method for creating an ultrashort temporal focus at a particular position at the output facet of a multimode optical fiber. The position of the ultrashort focus is only determined by the temporal shape of the input pulse. Changing that pulse shape allows scanning the focus at the output, e.g. to probe a scene by raster scanning the ultrashort pulse. The researchers demonstrated raster scanning along a square grid, but in principle every shape is possible, e.g. the following smiley, which is imaged via nonlinear medium to only show the position of the ultrashort pulses. The result is published in the journal Optics Express.

What is the exact path of light inside a highly scattering material like white paint? This is a question that is impossible to answer, as the particles inside the paint are distributed randomly. This, at the same time, is a very attractive property for applying photonics in non-hackable security applications. Still, you would like to have a look inside, to see what is happening. For this reason, researchers of the University of Twente (MESA+ Institute), built a light scattering microcube that is both random and controlled. Contradictory as it seems, this is a way to exactly know what is happening inside. The research results are in Advanced Optical Materials.