Son et lumière in twisted space

Xinglin Zeng, a postdoc in Birgit Stiller's group at our institute, has recently reported the first observation of stimulated Brillouin scattering in the "twisted space" of chiral photonic crystal fibre (PCF). Drawn from a spinning preform, chiral PCF consists of a multi-helix of hollow channels swirling around a central glass core. This structure imposes a twist on the guided light, making possible novel studies of the interaction between circularly polarized light and microwave sound. Above a certain laser power, an intense acoustic wave is excited in the core, which reflects light backwards with a frequency down-shift in the 10 GHz range.

 “In twisted PCF, strict selection rules result in opposite circular polarization states for the forward and backward waves”, says Zeng. “The results open up new opportunities for chiral optomechanics, with potential applications in quantum optics, fiber sensing, optical tweezers, Brillouin gyroscopes and lasers” says Stiller.

(1) Experimental Set-up. (C) Birgit Stiller / Max Planck Institute for the Science of Light

(2) Visualisation of light-sound interaction in chiral photonic crystal fibre. Arrows are circular polarisation states (C) Xinglin Zeng / Max Planck Institute for the Science of Light



Stimulated Brillouin scattering in chiral photonic crystal fiber, Xinglin Zeng, Wenbin He, Michael H. Frosz, Andreas Geilen, Paul Roth, Gordon K. L. Wong, Philip St.J. Russell, Birgit Stiller, DOI: 10.1364/PRJ.443706, Photonics Research, 2022.

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