4 Chirality and Antiferromagnetism in Optical Metasurfaces
81
Fig. 4.1 The summary
about the efficiency limits of
optical metasurfaces. The
limit for metasurfaces
supporting either electric or
magnetic resonance is 25%,
while the high aspect-ratio
dielectric and multilayer
metasurfaces have the
efficiency limit of 100%
current metasurface community. To achieve high efficiency, optical reflective metasurfacecs employ the gold (Au) at the near-infrared frequencies, silver (Ag) at the
visible wavelengths and aluminum (Al) at the ultrav-violet spectrum, while transmission metasurfaces prefer the silicon (Si) for the near-infrared light, titanium dioxide
(TiO 2 ), gallium nitride (GaN), silicon nitride (Si 3 N 4 ) and gallium phosphide (GaP)
for visible light, niobium pentoxide (Ni 2 O 5 ), hafnium dioxide (HfO 2 ) and diamond
for ultra-violet light. Figure 4.1 shows a brief summary about the efficiency limit of
optical metasurfaces with electric and magnetic resonances.
Optical devices demonstrated by metasurfaces are frequently called as metaoptics. Compared with traditional optics, meta-optics such as metalenses [33, 45, 46],
meta-holograms [37, 38, 43, 44, 47–50], meta-gratings [51–54], beam meta-splitters
[55, 56], vortex meta-generators [57, 58], meta-retroreflectors [59], meta-biosensors
[60] and image meta-processors [61] have the advantages of compact volume, polarization sensitivity, multiplexing functionality, large degree of freedom, high integration and light weight for portable devices. Benefitting from these novel properties,
meta-optics could be used in high-resolution imaging, display, nano-lasing, beam
shaping, information recognition, nonlinear optics, quantum physics, bio-sensing,
spectroscopy and augmented reality. Note that, this technology of optical metasurfaces is hunting for its killer-man applications where only meta-optics can solve the
relative problems so that the meta-devices cannot be substituted by others. Before
reaching this goal, we speculate that optical reconfigurable metasurfaces might be
the most important issue that should be steadily solved, although many intriguing
proposals [62–69] have been reported in a limited or imperfect functionality for the
practical usage.
81
Fig. 4.1 The summary
about the efficiency limits of
optical metasurfaces. The
limit for metasurfaces
supporting either electric or
magnetic resonance is 25%,
while the high aspect-ratio
dielectric and multilayer
metasurfaces have the
efficiency limit of 100%
current metasurface community. To achieve high efficiency, optical reflective metasurfacecs employ the gold (Au) at the near-infrared frequencies, silver (Ag) at the
visible wavelengths and aluminum (Al) at the ultrav-violet spectrum, while transmission metasurfaces prefer the silicon (Si) for the near-infrared light, titanium dioxide
(TiO 2 ), gallium nitride (GaN), silicon nitride (Si 3 N 4 ) and gallium phosphide (GaP)
for visible light, niobium pentoxide (Ni 2 O 5 ), hafnium dioxide (HfO 2 ) and diamond
for ultra-violet light. Figure 4.1 shows a brief summary about the efficiency limit of
optical metasurfaces with electric and magnetic resonances.
Optical devices demonstrated by metasurfaces are frequently called as metaoptics. Compared with traditional optics, meta-optics such as metalenses [33, 45, 46],
meta-holograms [37, 38, 43, 44, 47–50], meta-gratings [51–54], beam meta-splitters
[55, 56], vortex meta-generators [57, 58], meta-retroreflectors [59], meta-biosensors
[60] and image meta-processors [61] have the advantages of compact volume, polarization sensitivity, multiplexing functionality, large degree of freedom, high integration and light weight for portable devices. Benefitting from these novel properties,
meta-optics could be used in high-resolution imaging, display, nano-lasing, beam
shaping, information recognition, nonlinear optics, quantum physics, bio-sensing,
spectroscopy and augmented reality. Note that, this technology of optical metasurfaces is hunting for its killer-man applications where only meta-optics can solve the
relative problems so that the meta-devices cannot be substituted by others. Before
reaching this goal, we speculate that optical reconfigurable metasurfaces might be
the most important issue that should be steadily solved, although many intriguing
proposals [62–69] have been reported in a limited or imperfect functionality for the
practical usage.