Expérimental et théorique
The past few years have witnessed impressive developments in optical sources capable of emitting light with non-trivial phase and/or polarization patterns, such as optical vortices. These structured beams are of interest in many scientific fields ranging from sub-diffraction imaging techniques to optical tweezers. Because structured beams are carved by carefully tailored interferences, their construction requires light possessing a high degree of coherence—typically light produced by a laser. One research direction pursued by our team is to achieve the same feat with sources of non-lasing light. Non-lasing light (e.g. light from the sun, from LEDs, from candles…) lacks of the coherence properties of lasers, meaning that it is not in principle possible to shape all the emitted photons into a single beam. Our strategy to overcome this fundamental limit is to hybridize a luminescent medium with a structured pattern (a “metasurface”). Rather than emitting random photons in free space, the luminescent medium will emit light with properties dictated by the metasurface. We have already validated these ideas for optical vortices and beams with azimutal polarization. The goal of this internship is to generalize these results to vortex knots and vortex links, which are beams with dark phase singularities that form non-trivial topologies such as interlaced or knotted loops. The work will include calculations, cleanroom fabrication and optical characterization.