Zobrazeno 1 - 10
of 74
pro vyhledávání: '"Dirdal, Christopher A."'
A conventional refractive lens surface can act as a positive (converging) or negative (diverging) lens, but the same surface cannot act as both. We show that a geometric phase metasurface lens can have the unique property of acting both as a positive
Externí odkaz:
http://arxiv.org/abs/2402.02755
MEMS-tunable dielectric metasurface lens using thin-film PZT for large displacements at low voltages
Autor:
Dirdal, Christopher A., Thrane, Paul C. V., Dullo, Firehun T., Gjessing, Jo, Summanwar, Anand, Tschudi, Jon
Tunable focusing is a desired property in a wide range of optical imaging and sensing technologies but has tended to require bulky components which cannot be integrated on-chip and have slow actuation speeds. Recently, integration of metasurfaces int
Externí odkaz:
http://arxiv.org/abs/2112.10130
Autor:
Meng, Chao, Thrane, Paul C. V., Ding, Fei, Gjessing, Jo, Thomaschewski, Martin, Wu, Cuo, Dirdal, Christopher, Bozhevolnyi, Sergey I.
Optical metasurfaces (OMSs) have shown unprecedented capabilities for versatile wavefront manipulations at the subwavelength scale, thus opening fascinating perspectives for next generation ultracompact optical devices and systems. However, to date,
Externí odkaz:
http://arxiv.org/abs/2101.08834
Autor:
Dirdal, Christopher A., Jensen, Geir Uri, Angelskår, Hallvard, Thrane, Paul Conrad Vaagen, Gjessing, Jo, Ordnung, Daniel Alfred
We demonstrate the fabrication of diffraction-limited dielectric metasurface lenses for NIR by use of standard industrial high throughput silicon processing techniques: UV Nano Imprint Lithography (UV-NIL) combined with continuous Reactive Ion Etchin
Externí odkaz:
http://arxiv.org/abs/2004.11133
Publikováno v:
Phys. Rev. B 99, 064407 (2019)
We state and compare four different definitions of magnetic permeability for periodic, artificial media, or metamaterials. The connection between them, and properties in general, are discussed in detail, including causality, passivity, symmetry, asym
Externí odkaz:
http://arxiv.org/abs/1810.07996
Publikováno v:
IEEE Transactions on Antennas and Propagation, vol. 66, no. 11, pp. 6403-6407, Nov. 2018
The higher order multipoles above the electric quadrupole are commonly neglected in metamaterial homogenization. We show that they nevertheless can be significant when second order spatial dispersive effects, such as the magnetic response, are consid
Externí odkaz:
http://arxiv.org/abs/1701.01708
Publikováno v:
Phys. Rev. B 91, 134102 (2015)
Metamaterial effective parameters may exhibit freedom from typical dispersion constraints. For instance, the emergence of a magnetic response in arrays of split-ring resonators for long wavelengths cannot be attained in a passive continuous system ob
Externí odkaz:
http://arxiv.org/abs/1410.7158
Publikováno v:
Dirdal, C.A. & Skaar, J. Eur. Phys. J. B (2018) 91: 131
It is well known that the usual Kramers--Kronig relations for the relative permeability function $\mu(\omega)$ are not compatible with diamagnetism ($\mu(0)<1$) and a positive imaginary part ($\text{Im}\,\mu(\omega)>0$ for $\omega>0$). We demonstrate
Externí odkaz:
http://arxiv.org/abs/1410.5999
Publikováno v:
Phys. Rev. A 88, 033834 (2013)
We prove that all functions obeying the Kramers-Kronig relations can be approximated as superpositions of Lorentzian functions, to any precision. As a result, the typical text-book analysis of dielectric dispersion response functions in terms of Lore
Externí odkaz:
http://arxiv.org/abs/1307.7540
Autor:
Angelskår, Hallvard, Dirdal, Christopher Andrew, Tronstad, Tron Vedul, Kavli, Tom, Vogl, Andreas
Publikováno v:
In Ultrasonics July 2019 96:160-164