Flat Helical Nanosieves

Abstract

Compact and miniaturized devices with flexible functionalities are always highly demanded in optical integrated systems. Plasmonic nanosieve has been successfully harnessed as an ultrathin flat platform for complex manipulation of light, including holography, vortex generation, and nonlinear processes. Compared with most of the reported single-functional devices, multifunctional nanosieves might find more complex and novel applications across nanophotonics, optics, and nanotechnology. Here, a promising roadmap for nanosievebased helical devices is experimentally demonstrated, which achieves full manipulations of optical vortices, including its generation, hybridization, spatial multiplexing, focusing and nondiffraction propagation, etc., by controlling the geometric phase of spin light via over 121 thousands of spatially rotated nanosieves. Thanks to such spin-conversion nanosieve helical elements, it is no longer necessary to employ the conventional two-beam interferometric measurement to characterize optical vortices, while the interference can be realized natively without changing any parts of the current setup. The proposed strategy makes the far-field manipulations of optical orbital angular momentum within an ultrathin interface viable and bridges singular optics and integrated optics. In addition, it enables more unique extensibility and flexibility in versatile optical elements than traditional phase-accumulated helical optical devices.

Recent Progress in Far-Field Optical Metalenses

“…In this case, similarly shaped nano-voids (Babinet-inverted, or complementary nano-antennas) have been milled in a thin metallic film, which provides a significantly higher signal-to-noise ratio [57]. More recently, helical devices composed of more than 121 thousands of spatially rotated nanosieves have been fabricated to achieve full manipulations of optical vortices by controlling the geometric phase of spin light, enabling for instance to create multifoci vortex lenses [58]. This approach has been also utilized in the development of innovative terahertz imaging systems.…”

A Spin‐Encoded All‐Dielectric Metahologram for Visible Light

“…Metasurfaces, the subwavelength‐thick counterparts of metamaterials with exceptional capabilities of tailoring the wavefront of light in any desired fashion, provide an attractive platform to realize CGHs. With sub‐wavelength nanoresonators, metasurfaces can spatially modulate the amplitude, phase, and polarization of incident light to realize high‐resolution holograms and can overcome problems like higher order diffraction and twin imaging. Therefore, metasurfaces offer remarkable promise in realizing both 2D and 3D imaging.…”

Spiral Photon Sieves Apodized by a Bessel-Like Window

“…So far, a large number of diffractive optical elements based on this type of multi-micropore structure have emerged, such as flat helical nanosieves [17] and ultrahighcapacity non-periodic photon sieves [18]. The amplitude, phase and polarization of the diffracted light field behind these multi-micropore structures can be effectively controlled by adjusting the geometry positions and sizes of individual holes with an excellent transmittance modulation window function or other algorithm.…”