Recently, color generation in resonant nanostructures have been intensively studied. Despite of their exciting progresses, the structural colors are usually generated by the plasmonic resonances of metallic nanoparticles. Due to the inherent plasmon damping, such plasmonic nanostructures are usually hard to create very distinct color impressions. Here we utilize the concept of metasurfaces to produce all-dielectric, low-loss, and high-resolution structural colors. We have fabricated TiO2 metasurfaces with electron-beam lithography and a very simple lift-off process. The optical characterizations showed that the TiO2 metasurfaces with different unit sizes could generate high reflection peaks at designed wavelengths. The maximal reflectance was as high as 64% with full width at half-maximum (fwhm) around 30 nm. Consequently, distinct colors have been observed in bright field and the generated colors covered the entire visible spectral range. The detailed numerical analysis shows that the distinct colors wer...

All-Dielectric Full-Color Printing with TiO2 Metasurfaces

Formation, adhesion, and accumulation of ice, snow, frost, glaze, rime, or their mixtures can cause severe problems for solar panels, wind turbines, aircrafts, heat pumps, power lines, telecommunication equipment, and submarines. These problems can decrease efficiency in power generation, increase energy consumption, result in mechanical and/or electrical failure, and generate safety hazards. To address these issues, the fundamentals of interfaces between liquids and surfaces at low temperatures have been extensively studied. This has lead to development of so called “icephobic” surfaces, which possess a number of overlapping, yet distinctive, characteristics from superhydrophobic surfaces. Less attention has been given to distinguishing differences between formation and adhesion of ice, snow, glaze, rime, and frost or to developing a clear definition for icephobic, or more correctly pagophobic, surfaces. In this review, we strive to clarify these differences and distinctions, while providing a comprehensive definition of icephobicity. We classify different canonical families of icephobic (pagophobic) surfaces providing a review of those with potential for scalable and robust development.

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Durable and scalable icephobic surfaces: similarities and distinctions from superhydrophobic surfaces.

By doping an organic compound functioning as an electron donor (hereinafter referred to as donor molecules) into an organic compound layer contacting a cathode, donor levels can be formed between respective LUMO (lowest unoccupied molecular orbital) levels between the cathode and the organic compound layer, and therefore electrons can be injected from the cathode, and transmission of the injected electrons can be performed with good efficiency. Further, there are no problems such as excessive energy loss, deterioration of the organic compound layer itself, and the like accompanying electron movement, and therefore an increase in the electron injecting characteristics and a decrease in the driver voltage can both be achieved without depending on the work function of the cathode material.

Light Emitting Device

To move beyond colorant-based pigmentation display technologies, a variety of photonic and plasmonic crystal based structures have been designed and applied as colour filters. Nanostructure based colour filtering offers increased efficiencies, low power consumption, slim dimensions, and enhanced resolution. However, incident angle tolerance still needs to be improved. In this work, we propose a new scheme through localized resonance in metallic nanoslits by light funneling. Angle insensitive colour filters up to ±80 degrees have been achieved, capable of wide colour tunability across the entire visible band with pixel size beyond the diffraction limit (~λ/2). This work opens the door to angle insensitive manipulation of light with structural filtering.

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Angle-Insensitive Structural Colours based on Metallic Nanocavities and Coloured Pixels beyond the Diffraction Limit

Inspired by the self-cleaning and water-repellent properties of plants and animals in the natural world, superhydrophobic and superoleophobic materials develop quickly, and are of great interest in academic and industrial areas. Although various chemicals have been used, silanes and silicones play very important roles in the preparation of superhydrophobic and superoleophobic materials. Approximately 25% of the literature about superhydrophobic and superoleophobic materials is based on silanes and silicones. Thus, we believe that an exhaustive literature review from the viewpoint of silane and silicone chemistry is now pertinent to give an overview of the recent progress about their roles in the preparation of superhydrophobic and superoleophobic materials. First of all, we hope to overview the roles of silanes and silicones in constructing micro-/nanostructures, decreasing the surface energy and/or as binders for the fabrication of superhydrophobic and superoleophobic surfaces. We will then focus on the roles of silanes and silicones in the formation of superhydrophobic and superoleophobic particles, sponges and aerogels. In the conclusions, we will summarize the roles of silanes and silicones in forming superhydrophobic and superoleophobic materials, and the challenges in the field. Overall, this review will hopefully help readers to use silanes and silicones dexterously in the design of novel superhydrophobic and superoleophobic materials.

Roles of silanes and silicones in forming superhydrophobic and superoleophobic materials

Reflective color filters using two-dimensional photonic crystals based on sub-wavelength gratings were proposed and constructed. Using low-cost nanoimprint lithography, an amorphous silicon layer was deposited through the low-temperature PECVD process and patterned into two-dimensional structures. The isolated amorphous silicon patterns were readily crystallized using a multi-shot excimer laser annealing at low energy. A study of the close relationship between color filter reflectance and silicon pattern crystallinity is introduced. Theoretical and experimental results show that the proposed color filters have high reflectance and, moreover, decrease the dependence on incident angle compared to one-dimensional photonic crystal color filters.

Two-dimensional photonic crystal color filter development

A heat assisted magnetic recording (HAMR) head and manufacturing method are provided. The HAMR head is mounted on a slider having an air-bearing surface (ABS) and includes a substrate; a recording unit formed on the substrate and having a stepped end; a waveguide located in a space formed by the stepped end; and a near field light emission (NFE) pole located adjacent to the recording unit and having an end located on a same plane as the ABS. The method includes forming a cladding layer on a substrate; forming a first metal layer on the cladding layer; etching a part of the first metal layer; forming a core layer on the etched region; forming a refraction part in a part of the core layer; forming a second metal layer the first metal layer and the core layer; and forming a recording unit on the second metal layer.

Heat assisted magnetic recording head and method of manufacturing the same

A heat assisted magnetic recording (HAMR) head is provided. The HAMR head is mounted in a slider having an ABS that faces a recording medium and illuminates light on the local area of the recording medium, and includes a recording unit that performs recording and a near field light emitter that illuminates near field light onto the local area of the recording medium, the near field light emitter including a light source, a waveguide, and a near field light emission (NFE) pole located between the recording unit and the waveguide, and which generates near field light that is illuminated on the recording medium using light transmitted through the waveguide.

Heat assisted magnetic recording head

Most current research on nanocomposites has focused on their bulk attributes, i.e., electrical, microwave, thermal, and mechanical properties. In practical applications, surface properties such as robustness against environmental contamination are critical design considerations if intrinsic properties are to be maintained. The aim of this research is to combine the bulk properties of nanocomposites with the superhydrophobic surface properties provided by imprinting techniques to create a single multi-functional system with enhanced bulk properties. We report the development of a highly conductive superhydrophobic nanotube composite, which is directly superimposed with a durable dual hole pattern through imprinting techniques. The dual hole pattern avoids the use of high slenderness ratio structures resulting in a surface which is robust against physical damage. Its stable superhydrophobic properties were characterized both theoretically and experimentally. By incorporating high aspect ratio carbon nanotubes (CNTs), the dual patterned composites can also be effectively used for anti-icing and deicing applications where their superhydrophobic surface suppresses ice formation and their quick electric heating response at low voltage eliminates remaining frost. In addition, superior electromagnetic interference (EMI) shielding effectiveness (SE) was attained, with one of the highest values ever reported in the literature.

Design of multi-functional dual hole patterned carbon nanotube composites with superhydrophobicity and durability

A metallic wave guide and a light delivery module are provided. The metallic waveguide includes a metal body formed of a conductive metal and having an aperture formed therethrough, the aperture having input and output ends. The aperture has a bent portion for changing a light traveling direction between the input and output ends, and a tapered portion between the bent portion and the output end. The tapered portion has a width that is gradually reduced toward the output end, and the aperture is formed in a C-shape by a ridge formed on an inner surface of the metal body.

90°-bent metallic waveguide having tapered c-shaped aperture, method of fabricating the waveguide, light delivery module including the waveguide, and heat assisted magnetic recording head having the waveguide

Jin-Seung Sohn

Papers

Two-dimensional photonic crystal color filter development

Heat assisted magnetic recording head and method of manufacturing the same

Heat assisted magnetic recording head

Design of multi-functional dual hole patterned carbon nanotube composites with superhydrophobicity and durability

90°-bent metallic waveguide having tapered c-shaped aperture, method of fabricating the waveguide, light delivery module including the waveguide, and heat assisted magnetic recording head having the waveguide