Bending and twisting light’s polarization into a Möbius strip

01.01.2016, 00:00

Newsletter 9

If one end of a paper strip is twisted by 180° and both ends are glued together, a fascinating object is created – a Möbius strip. The introduction of a half-twist has striking consequences for the strip properties. For example, it has only one side and a single edge or boundary (see Figure). We all have already seen Möbius strips in the form of sculptures or drawings, or maybe have even constructed one ourselves. Nevertheless, it seems quite counterintuitive that these objects can also be formed by the polarization of light. A decade ago, Isaac Freund theoretically proposed the occurrence of these unusual optical topologies in interfering light beams. Recently, we proved the existence of optical polarization Möbius strips experimentally for the first time. In the lab, we focused a superposition of two polarized light beams tightly, resulting in the creation of nanoscopic versions of Möbius strips. We took advantage of a nano-probing technique developed in the group to measure the distribution of the electric field in the focal plane. By retrieving the local polarization ellipses from the electric field information, we unveiled the hidden Möbius strips formed by the ellipse axes (see arrows in Figure).

Contact: peter.banzer(at)mpl.mpg(dot)de
Group: Leuchs Division (InMik)
Reference: T. Bauer et al., Science 347, 964-966 (2015).