TY - JOUR
T1 - Interferometric Evanescent Wave Excitation of a Nanoantenna for Ultrasensitive Displacement and Phase Metrology
AU - Wei, Lei
AU - Zayats, Anatoly V.
AU - Rodríguez-Fortuño, Francisco J.
PY - 2018/11
Y1 - 2018/11
N2 - We propose a method for ultrasensitive displacement and phase measurements based on a nanoantenna illuminated with interfering evanescent waves. We show that with a proper nanoantenna design, tiny displacements and relative phase variations can be converted into changes of the scattering direction in the Fourier space. These sensitive changes stem from the strong position dependence of the orientation of the purely imaginary Poynting vector produced in the interference pattern of evanescent waves. Using strongly confined evanescent standing waves, high sensitivity is demonstrated on the nanoantenna's zero-scattering direction, which varies linearly with displacement over a wide range. With weakly confined evanescent wave interference, even higher sensitivity to tiny displacement or phase changes can be reached near a particular location. The high sensitivity of the proposed method can form the basis for many metrology applications. Furthermore, this concept demonstrates the importance of the imaginary part of the Poynting vector, a property that is related to reactive power and is often ignored in photonics.
AB - We propose a method for ultrasensitive displacement and phase measurements based on a nanoantenna illuminated with interfering evanescent waves. We show that with a proper nanoantenna design, tiny displacements and relative phase variations can be converted into changes of the scattering direction in the Fourier space. These sensitive changes stem from the strong position dependence of the orientation of the purely imaginary Poynting vector produced in the interference pattern of evanescent waves. Using strongly confined evanescent standing waves, high sensitivity is demonstrated on the nanoantenna's zero-scattering direction, which varies linearly with displacement over a wide range. With weakly confined evanescent wave interference, even higher sensitivity to tiny displacement or phase changes can be reached near a particular location. The high sensitivity of the proposed method can form the basis for many metrology applications. Furthermore, this concept demonstrates the importance of the imaginary part of the Poynting vector, a property that is related to reactive power and is often ignored in photonics.
UR - http://www.scopus.com/inward/record.url?scp=85056382754&partnerID=8YFLogxK
U2 - 10.1103/PhysRevLett.121.193901
DO - 10.1103/PhysRevLett.121.193901
M3 - Article
C2 - 30468596
AN - SCOPUS:85056382754
SN - 0031-9007
VL - 121
JO - Physical Review Letters
JF - Physical Review Letters
IS - 19
M1 - 193901
ER -