Optomechanics of Metasurfaces

Polarization Optomechanics
Mechanical (a) and Electromagnetic (b) simulations of the optomechanical metasurface, which can be used for polarization modulation (c) and optical spring effect based polarimetry (d)

The class of photonic artificial devices has shown extraordinary capabilities in reproducing and then surpassing many light-based effects found in natural world. Among the others, chiral metasurfaces have shown dichroism amplitudes even larger than the ones in chiral bio-molecules. Combining metasurfaces with mechanical elements , we add a dynamic component to the static properties of the device. To this end, we designed and fabricated a minimal-shape metasurface by patterning holes in a GaAs membrane [1]. By activating the fundamental mechanical mode through piezo-actuation, we can modulate the polarization in non-trivial path on the Poincaré sphere surface, at a frequency of ~ 350 kHz with an amplitude exceeding 0.5 rad. Employing the back-action of light on the mechanical resonator, we can control its amplitude and peak frequency by changing the polarization state of impinging laser light. Producing a distinct set of values for each polarization, a probe of the mechanical resonance returns a fast, full polarimetry of light , inaugurating a completely novel technique of polarization-based optics [2]. The potential of working with the versatile GaAs offers several perspectives in combining polarization optomechanics with active light emitting elements in heterostructured quantum-wells or employing the natural material piezoelectricity for an improved control of the mechanical coherent motion without the need of external actuators.

[1] SS. Zanotto, G. Mazzamuto, F. Riboli, G. Biasiol, G. C. La Rocca, A. Tredicucci and A. Pitanti Photonic bands, superchirality, and inverse design of a chiral minimal metasurface , Nanophotonics (2019)

[2] S. Zanotto, A. Tredicucci, D. Navarro-Urrios, M. Cecchini, G. Biasiol, D. Mencarelli, L. Pierantoni and A. Pitanti, Optomechanics of dielectric chiral metasurfaces , Adv. Opt. Mat. (2020)


[Ended in February 2020]


  • Dr. Daniel Navarro-Urrios, University of Barcelona
  • Dr. Marco Cecchini, CNR - Istituto Nanoscienze, NEST Lab., Pisa
  • Dr. Giorgio Biasiol, CNR - Istituto Officina dei Materiali, Trieste