scholarly journals Metasurface Holography in the Microwave Regime

Photonics ◽  
2021 ◽  
Vol 8 (5) ◽  
pp. 135
Author(s):  
Guanyu Shang ◽  
Zhuochao Wang ◽  
Haoyu Li ◽  
Kuang Zhang ◽  
Qun Wu ◽  
...  
Keyword(s):  
Data Storage ◽  
Research Field ◽  
Optical Data Storage ◽  
Optical Data ◽  
Optical Fields ◽  
Holographic Imaging ◽  
Wide Range ◽  
Critical Issues ◽  
Optical Applications ◽  
Microwave Regime

Hologram technology has attracted a great deal of interest in a wide range of optical fields owing to its potential use in future optical applications, such as holographic imaging and optical data storage. Although there have been considerable efforts to develop holographic technologies using conventional optics, critical issues still hinder their future development. A metasurface, as an emerging multifunctional device, can manipulate the phase, magnitude, polarization and resonance properties of electromagnetic fields within a sub-wavelength scale, opening up an alternative for a compact holographic structure and high imaging quality. In this review paper, we first introduce the development history of holographic imaging and metasurfaces, and demonstrate some applications of metasurface holography in the field of optics. We then summarize the latest developments in holographic imaging in the microwave regime. These functionalities include phase- and amplitude-based design, polarization multiplexing, wavelength multiplexing, spatial asymmetric propagation, and a reconfigurable mechanism. Finally, we conclude briefly on this rapidly developing research field and present some outlooks for the near future.

TEM Specimen Preparation Techniques and Analysis of Photo-Thermo-Refractive Glasses (PTRG)

2001 ◽  
Vol 7 (S2) ◽  
pp. 432-433
Author(s):  
H. Francois-Saint-Cyr ◽  
K. Elshot ◽  
P. Le Coustumer ◽  
X. Bourrat ◽  
K. Richardson ◽  
...  
Keyword(s):  
Data Storage ◽  
Refractive Index Change ◽  
Optical Data Storage ◽  
Optical Data ◽  
Specimen Preparation ◽  
Active Components ◽  
Index Change ◽  
Transmission Electron ◽  
Optical Applications ◽  
Underlying Mechanisms

Due to their ability to undergo a refractive index change (Δn) induced by appropriate UV irradiation and thermal development, Photo-Thermo-Refractive (PTR) glasses are candidate materials for use in optical applications such as hologram recording, optical data storage, or spectral filters. Although this induced index modulation (Δn) has been characterized in terms of its optical ramifications, glass scientists are working to understand more clearly, the underlying mechanisms associated with the photo-induced crystallization process. For example, the phase, concentration and size of crystals responsible for the induced index change, the diffusion and growth process leading to the resultant optical behavior, and the precise role of the active components of PTR glasses, has yet to be completely elucidated. Numerous techniques have been employed to address these questions and this paper reports results of sample preparation and analysis of PTR glasses using Transmission Electron Microscopy (TEM).

scholarly journals Active analog tuning of the phase of light in the visible regime by bismuth-based metamaterials

Nanophotonics ◽  
2020 ◽  
Vol 9 (4) ◽  
pp. 885-896 ◽  
Author(s):  
Marina Garcia-Pardo ◽  
Eva Nieto-Pinero ◽  
Amanda K. Petford-Long ◽  
Rosalia Serna ◽  
Johann Toudert
Keyword(s):  
Data Storage ◽  
Optical Memory ◽  
Visible Spectral Region ◽  
Optical Data Storage ◽  
Optical Data ◽  
Photonic Switching ◽  
Active Analog ◽  
Wide Range ◽  
Analog Approach ◽  
Solid Liquid

AbstractThe active and analog tuning of the phase of light by metamaterials is needed to boost the switching performance of photonic devices. However, demonstrations of this type of tuning in the pivotal visible spectral region are still scarce. Herein, we report the active analog tuning of the phase of visible light reflected by a bismuth (Bi)-based metamaterial, enabled by a reversible solid-liquid transition. This metamaterial, fabricated by following a lithography-free approach, consists of two-dimensional assemblies of polydisperse plasmonic Bi nanostructures embedded in a refractory and transparent aluminum oxide matrix. The analog tuning of the phase is achieved by the controlled heating of the metamaterial to melt a fraction of the nanostructures. A maximum tuning of 320° (1.8 π) is observed upon the complete melting of the nanostructures at 230°C. This tuning is reversible by cooling to 25°C. In addition, it presents a wide hysteretic character due to liquid Bi undercooling. This enables the phase achieved by this analog approach to remain stable over a broad temperature range upon cooling and until re-solidification occurs around 100°C. Therefore, Bi-based metamaterials are endowed with analog optical memory capabilities, which are appealing for a wide range of applications, including optical data storage with enhanced information density or bistable photonic switching with a tunable “on” state.

New Photopolymers Based on Two-Photon Absorbing Chromophores and Application to Three-Dimensional Microfabrication and Optical Storage

1997 ◽  
Vol 488 ◽  
Author(s):  
B. H. Cumpston ◽  
J. E. Ehrlich ◽  
L. L. Erskin ◽  
A. A. Heikalt ◽  
Z.-Y. Hu ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Data Storage ◽  
Three Dimensional ◽  
Optical Data Storage ◽  
Photon Absorption ◽  
Transfer Reactions ◽  
Optical Data ◽  
Two Photon ◽  
Wide Range ◽  
Charge Transfer Reactions

AbstractMolecules exhibiting strong two-photon absorption hold great potential for a wide range of applications including two-photon fluorescence imaging, three-dimensional (3D) optical data storage, and 3D microfabrication. We have observed two-photon absorptivities as high as 1500×10− 50 cm4 s/photon in bis-donor diphenylpolyene derivatives that are correlated to simultaneous charge transfer from the end groups to the polyene bridge in the molecule. Many of these molecules are also excellent photoexcitable electron donors that can initiate charge-transfer reactions with acrylate monomers. Marcus theory is used to describe the efficiency of these charge-transfer reactions. Polymerization rates have also been measured and we show that these twophoton chromophores display increased sensitivity and recording speed over conventional UV photo-initiators. The fabrication of complex, three-dimensional structures by twophoton polymerization is demonstrated and discussed in the context of advanced photonic applications.

scholarly journals Broadband generation of perfect Poincaré beams via dielectric spin-multiplexed metasurface

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Mingze Liu ◽  
Pengcheng Huo ◽  
Wenqi Zhu ◽  
Cheng Zhang ◽  
Si Zhang ◽  
...  
Keyword(s):  
Angular Momentum ◽  
Visible Light ◽  
Data Storage ◽  
Topological Charge ◽  
Single Layer ◽  
Optical Data Storage ◽  
Optical Data ◽  
Charge Number ◽  
Optical Applications ◽  
Broadband Generation

AbstractThe term Poincaré beam, which describes the space-variant polarization of a light beam carrying spin angular momentum (SAM) and orbital angular momentum (OAM), plays an important role in various optical applications. Since the radius of a Poincaré beam conventionally depends on the topological charge number, it is difficult to generate a stable and high-quality Poincaré beam by two optical vortices with different topological charge numbers, as the Poincaré beam formed in this way collapses upon propagation. Here, based on an all-dielectric metasurface platform, we experimentally demonstrate broadband generation of a generalized perfect Poincaré beam (PPB), whose radius is independent of the topological charge number. By utilizing a phase-only modulation approach, a single-layer spin-multiplexed metasurface is shown to achieve all the states of PPBs on the hybrid-order Poincaré Sphere for visible light. Furthermore, as a proof-of-concept demonstration, a metasurface encoding multidimensional SAM and OAM states in the parallel channels of elliptical and circular PPBs is implemented for optical information encryption. We envision that this work will provide a compact and efficient platform for generation of PPBs for visible light, and may promote their applications in optical communications, information encryption, optical data storage and quantum information sciences.

scholarly journals Structural and optical properties of amorphous Si–Ge–Te thin films prepared by combinatorial sputtering

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
C. Mihai ◽  
F. Sava ◽  
I. D. Simandan ◽  
A. C. Galca ◽  
I. Burducea ◽  
...  
Keyword(s):  
Optical Properties ◽  
Data Storage ◽  
Optical Sensors ◽  
Material Selection ◽  
Functional Materials ◽  
Stability Study ◽  
Optical Data Storage ◽  
Optical Data ◽  
Structural And Optical Properties ◽  
Topological Constraint

AbstractThe lack of order in amorphous chalcogenides offers them novel properties but also adds increased challenges in the discovery and design of advanced functional materials. The amorphous compositions in the Si–Ge–Te system are of interest for many applications such as optical data storage, optical sensors and Ovonic threshold switches. But an extended exploration of this system is still missing. In this study, magnetron co-sputtering is used for the combinatorial synthesis of thin film libraries, outside the glass formation domain. Compositional, structural and optical properties are investigated and discussed in the framework of topological constraint theory. The materials in the library are classified as stressed-rigid amorphous networks. The bandgap is heavily influenced by the Te content while the near-IR refractive index dependence on Ge concentration shows a minimum, which could be exploited in applications. A transition from a disordered to a more ordered amorphous network at 60 at% Te, is observed. The thermal stability study shows that the formed crystalline phases are dictated by the concentration of Ge and Te. New amorphous compositions in the Si–Ge–Te system were found and their properties explored, thus enabling an informed and rapid material selection and design for applications.

scholarly journals Optical Isomerization and Photo-Patternable Properties of GeO2/Ormosils Organic-Inorganic Composite Films Doped with Azobenzene

Coatings ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 818
Author(s):  
Xuehua Zhang ◽  
Qian Wang ◽  
Shun Liu ◽  
Wei Zhang ◽  
Fangren Hu ◽  
...  
Keyword(s):  
Optical Waveguide ◽  
Data Storage ◽  
Optical Switching ◽  
Sol Gel ◽  
Composite Films ◽  
Optical Data Storage ◽  
Optical Data ◽  
Single Chip ◽  
Coating Method ◽  
Inorganic Composite

GeO2/organically modified silane (ormosils) organic-inorganic composite films containing azobenzene were prepared by combining sol-gel technology and spin coating method. Optical waveguide properties including the refractive index and thickness of the composite films were characterized by using a prism coupling instrument. Surface morphology and photochemical properties of the composite films were investigated by atomic force microscope and Fourier transform infrared spectrometer. Results indicate that the composite films have smooth and neat surface, and excellent optical waveguide performance. Photo-isomerization properties of the composite films were studied by using a UV–Vis spectrophotometer. Optical switching performance of the composite films was also studied under the alternating exposure of 365 nm ultraviolet light and 410 nm visible light. Finally, strip waveguides and microlens arrays were built in the composite films through a UV soft imprint technique. Based on the above results, we believe that the prepared composite films are promising candidates for micro-nano optics and photonic applications, which would allow directly integrating the optical data storage and optical switching devices onto a single chip.

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