Visible-frequency asymmetric transmission devices incorporating a hyperbolic metamaterial

Abstract

Asymmetric electromagnetic transmission has been recently demonstrated using Lorentz-reciprocal devices, which exploit a variety of patterned structures of linear materials to break spatial inversion symmetry. However, nanofabrication challenges have so far precluded the fabrication of passive transmission structures with highly asymmetric responses at visible frequencies. Here we show that high-contrast asymmetric transmission of visible light can be provided by a planar device of wavelength-scale thickness incorporating a pair of nonsymmetric subwavelength gratings and a passive hyperbolic metamaterial engineered to display a transmission window centred at a lateral spatial frequency substantially exceeding the diffraction limit. Fabricated devices designed for operation at central wavelengths of 532 and 633 nm, respectively, display broadband, efficient asymmetric optical transmission with contrast ratios exceeding 14 dB. Owing to its planar configuration, small footprint and passive operation, this reciprocal transmission approach holds promise for integration within compact optical systems operating at visible frequencies.

Experimental demonstration of deflection angle tuning in unidirectional fishnet metamaterials at millimeter-waves

“…Asymmetric excitation of higher diffraction orders can be simply enabled in various volumetric and ultrathin structures by loading one of the interfaces with a grating-like structure. This strategy has successfully been realized in non-symmetric structures based on photonic crystals, [6][7][8][9]16 fishnet, 17 and multilayer metamaterials, 18 thin metallic gratings with slits, 10,19 and simple one-and twofraction gratings that contain Drude metals 7 or polar dielectrics. 20 Experimental results have been reported for acoustic, 9 microwave, 16,17 terahertz, 10 and optical 15,18 regimes.…”

Polarization State Manipulation of Electromagnetic Waves with Metamaterials and Its Applications in Nanophotonics

“…At optical waveband, asymmetric transmission can also be achieved, as shown in Figure 6c. The fabricated devices designed for operation at central wavelength of 532 and 633 nm, exhibit broadband, eicient asymmetric optical transmission with contrast ratios exceeding 14 dB [46]. The FDTD-simulated amplitude of the magnetic ield at an arbitrary time is shown in Figure 6d.…”

Nanophotonics-enabled smart windows, buildings and wearables

“…Angular selectivity in one layer first received major attention for windows [22,71] with oblique columnar films, and more recently special stacks of multiple very thin layers [72]. Such metamaterials can be treated as a single effective medium if they do not scatter, although photonic approaches enable additional tunability.…”