KEYWORDS: 3D displays, 3D image reconstruction, Far-field diffraction, Digital imaging, Holography, Computer generated holography, Field emission displays, Holograms, 3D modeling, Digital holography
The widespread use of holographic VR/AR devices are limited by bulky refractive and diffractive optics. To address these problems, a NED system combining the 3D CGH based on Fraunhofer diffraction and a metalens with 5 mm diameter as an eyepiece is proposed in this paper. Because of the capability of wavefront shaping in a subwavelength scale, the metalens eyepiece surly facilitates lightening the CGH-NED systems. Experiments are carried out for this design, where Fraunhofer diffraction with digital lens phases of different focal lengths are applied, and the metalens transforms the holographic reconstructed 3D image into virtual image to realize NED. The metalens eyepiece composed of silicon nitride anisotropic nanofins is fabricated with the diffraction efficiency and field of view for 532 nm incidence of 15.7% and 31°, respectively. Our work combining of CGH and metalens may provide a promising solution in future for computer-generated holographic 3D portable display.
As novel planar structures, the metasurfaces exhibit the unprecedented capability to manipulate the amplitude, phase, and polarization of electromagnetic waves. Therefore, metasurface is designed to apply to metalens, holography, nanoprinting display, encryption, and so on. It is very interesting and meaningful work to integrate bifocal metalens and nanoprinting images into a single metasurface. A method is proposed to combine propagation phase and geometric phase, as well as Malus's law to realize the function of the bifocal metalens and clear nanoprinting display in the near field which can be observed at a certain polarization. This original design expands the functional integration of metasurface and improves applications in image displays, optical storage, augmented reality, virtual reality, and many other related fields.
Metasurface optical elements such as metalenses have drawn great attentions for their capabilities of manipulating wavefront versatilely and miniaturizing traditional optical devices into ultrathin counterparts, and multi-functional metasurfaces such as bifocal metalenses have attracted tremendous interests due to their potential in system integration. In this paper, an approach to design polarization-dependent bifocal metalenses which are able to independently generate longitudinally or transversely bifocal spots under the incidence of circularly polarized light with arbitrary ellipticity is proposed and demonstrated by full-wave simulations. When the designed devices are illuminated with elliptically polarized lights at wavelength of 532 nm, both of the helicity-multiplexed bifocal spots appear simultaneously, and the relative intensity of both focal spots can be tuned in terms of the ellipticity of the polarization state. In addition, a polarization-independent metalens based on geometric phase modulation is illustrated and the focusing efficiency of it maintains stable ignoring the polarization state of the incident waves, which could be of vital importance in real applications. This design is of enormous potential of being applied in real compact optical systems such as imaging, display, microscopy, tomography, optical data storage and so on.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.