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A Random-displacement Measurement by Combining a Magnetic Scale and Two Fiber Bragg Gratings
Published on: September 30, 2019
Detecting nanometric displacements with optical ruler metrology
Guang Hui Yuan1, Nikolay I Zheludev2,3
1Centre for Disruptive Photonic Technologies, The Photonics Institute, SPMS, Nanyang Technological University, Singapore 637371, Singapore.
Abstract:
We introduce the optical ruler, an electromagnetic analog of a physical ruler, for nanoscale displacement metrology. The optical ruler is a complex electromagnetic field in which singularities serve as the marks on the scale. It is created by the diffraction of light on a metasurface, with singularity marks then revealed by high-magnification interferometric observation. Using a Pancharatnam-Berry phase metasurface, we demonstrate a displacement resolving power of better than 1 nanometer (λ/800, where λ is the wavelength of light) at a wavelength of 800 nanometers. We argue that a resolving power of ~λ/4000, the typical size of an atom, may be achievable. An optical ruler with dimensions of only a few tens of micrometers offers applications in nanometrology, nanomonitoring, and nanofabrication, particularly in the demanding and confined environment of future smart manufacturing tools.
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