Ultra-sensitive measurement of mechanical displacements with photonic gears

Event Details

  • Date:
  • Venue: ICFO - SMR
  • Address: Mediterranean Technology Park Av. Carl Friedrich Gauss, 3, 08860 Castelldefels
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ICFO Seminar


by Vincenzo d’Ambrosio, Universita’ Degli Studi Di Napoli Federico II


Accurately measuring mechanical displacements is essential for a vast portion of current technologies. Several optical techniques accomplish this task, allowing for non-contact sensing even below the diffraction limit. Structured light can be a resource for enhanced sensing purposes as for instance in the “photonic gears”. This technique enables a boost of the sensitivity in roll angle measurements thanks to a bidirectional mapping between the polarization state and a properly tailored vectorial mode of a paraxial light beam. Similarly, ultra-sensitive measurements of a transverse displacement can be performed by mapping it into the polarization rotation of a laser beam. By exploiting this technique, dubbed “linear photonic gears”, we measured, in ordinary ambient conditions, the relative shift between two objects with a resolution of 400 pm. We argue that a resolution of 50 pm should be achievable with existing state-of-the-art technologies. Our single-optical-path scheme is intrinsically stable and it could be implemented as a compact sensor, using cost effective integrated optics.