TY - JOUR
T1 - Extraordinarily large permittivity modulation in zinc oxide for dynamic nanophotonics
AU - Saha, Soham
AU - Dutta, Aveek
AU - DeVault, Clayton
AU - Diroll, Benjamin T.
AU - Schaller, Richard D.
AU - Kudyshev, Zhaxylyk
AU - Xu, Xiaohui
AU - Kildishev, Alexander
AU - Shalaev, Vladimir M.
AU - Boltasseva, Alexandra
N1 - Funding Information:
This work was performed in part at the Center for Nanoscale Materials, a U.S. Department of Energy Office of Science User Facility, and supported by the U.S. Department of Energy, Office of Science, under Contract No. DE-AC02-06CH11357. Part of this work was also supported by the Air Force Office of Scientific Research through Award Nos. FA9550-18-1-0002, and FA9550-19-S-0003. The authors acknowledge the support of the U.S. Department of Energy, Office of Basic Energy Sciences, Division of Materials Sciences and Engineering, under Award No. DE-SC0017717 (sample preparation), Office of Naval Research Grant N00014-18-1-2481, and DARPA/DSO Extreme Optics and Imaging (EXTREME) program HR00111720032.
Publisher Copyright:
© 2020
PY - 2021/3
Y1 - 2021/3
N2 - The dielectric permittivity of a material encapsulates the essential physics of light-matter interaction into the material's local response to optical excitation. Photo-induced modulation of the permittivity can enable an unprecedented level of control over the phase, amplitude, and polarization of light. Therefore, the detailed dynamic characterization of technology-relevant materials with substantially tunable optical properties and fast response times is a crucial step to realize tunable optical devices. This work reports on the extraordinarily large permittivity changes in zinc oxide thin films (up to −3.6 relative change in the real part of the dielectric permittivity at 1600 nm wavelength) induced by optically generated free carriers. We demonstrate broadband reflectance modulation up to 70% in metal-backed oxide mirrors at the telecommunication wavelengths, with picosecond-scale relaxation times. The epsilon near zero points of the films can be dynamically shifted from 8.5 µm to 1.6 µm by controlling the pump fluence. The modulation can be selectively enhanced at specific wavelengths employing metal-backed zinc oxide disks while maintaining picosecond-scale switching times. This work provides insights into the free-carrier assisted permittivity modulation in zinc oxide and could enable the realization of novel dynamic devices for beam-steering, polarizers, and spatial light modulators.
AB - The dielectric permittivity of a material encapsulates the essential physics of light-matter interaction into the material's local response to optical excitation. Photo-induced modulation of the permittivity can enable an unprecedented level of control over the phase, amplitude, and polarization of light. Therefore, the detailed dynamic characterization of technology-relevant materials with substantially tunable optical properties and fast response times is a crucial step to realize tunable optical devices. This work reports on the extraordinarily large permittivity changes in zinc oxide thin films (up to −3.6 relative change in the real part of the dielectric permittivity at 1600 nm wavelength) induced by optically generated free carriers. We demonstrate broadband reflectance modulation up to 70% in metal-backed oxide mirrors at the telecommunication wavelengths, with picosecond-scale relaxation times. The epsilon near zero points of the films can be dynamically shifted from 8.5 µm to 1.6 µm by controlling the pump fluence. The modulation can be selectively enhanced at specific wavelengths employing metal-backed zinc oxide disks while maintaining picosecond-scale switching times. This work provides insights into the free-carrier assisted permittivity modulation in zinc oxide and could enable the realization of novel dynamic devices for beam-steering, polarizers, and spatial light modulators.
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U2 - 10.1016/j.mattod.2020.10.023
DO - 10.1016/j.mattod.2020.10.023
M3 - Article
AN - SCOPUS:85097077252
VL - 43
SP - 27
EP - 36
JO - Materials Today
JF - Materials Today
SN - 1369-7021
ER -