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Materials Science and Engineering

Iowa State University Patents

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Full-Text Articles in Physics

Metallic Layer-By-Layer Photonic Crystals For Linearly-Polarized Thermal Emission And Thermophotovoltaic Device Including Same, Jae-Hwang Lee, Kai-Ming Ho, Kristen P. Constant Jul 2016

Metallic Layer-By-Layer Photonic Crystals For Linearly-Polarized Thermal Emission And Thermophotovoltaic Device Including Same, Jae-Hwang Lee, Kai-Ming Ho, Kristen P. Constant

Iowa State University Patents

Metallic thermal emitters consisting of two layers of differently structured nickel gratings on a homogeneous nickel layer are fabricated by soft lithography and studied for polarized thermal radiation. A thermal emitter in combination with a sub-wavelength grating shows a high extinction ratio, with a maximum value close to 5, in a wide mid-infrared range from 3.2 to 7.8 μm, as well as high emissivity up to 0.65 at a wavelength of 3.7 μm. All measurements show good agreement with theoretical predictions. Numerical simulations reveal that a high electric field exists within the localized air space surrounded ...


Soft Lithography Microlens Fabrication And Array For Enhanced Light Extraction From Organic Light Emitting Diodes (Oleds), Wai Y. Leung, Joong-Mok Park, Zhengqing Gan, Kristen P. Constant, Joseph Shinar, Ruth Shinar, Kai-Ming Ho Jun 2014

Soft Lithography Microlens Fabrication And Array For Enhanced Light Extraction From Organic Light Emitting Diodes (Oleds), Wai Y. Leung, Joong-Mok Park, Zhengqing Gan, Kristen P. Constant, Joseph Shinar, Ruth Shinar, Kai-Ming Ho

Iowa State University Patents

Provided are microlens arrays for use on the substrate of OLEDs to extract more light that is trapped in waveguided modes inside the devices and methods of manufacturing same. Light extraction with microlens arrays is not limited to the light emitting area, but is also efficient in extracting light from the whole microlens patterned area where waveguiding occurs. Large microlens array, compared to the size of the light emitting area, extract more light and result in over 100% enhancement. Such a microlens array is not limited to (O)LEDs of specific emission, configuration, pixel size, or pixel shape. It is ...


Multi-Channel Polarized Thermal Emitter, Jae-Hwang Lee, Kai-Ming Ho, Kristen P. Constant Jul 2013

Multi-Channel Polarized Thermal Emitter, Jae-Hwang Lee, Kai-Ming Ho, Kristen P. Constant

Iowa State University Patents

A multi-channel polarized thermal emitter (PTE) is presented. The multi-channelPTE can emit polarized thermal radiation without using a polarizer at normal emergence. The multi-channel PTE consists of two layers of metallic gratings on a monolithic and homogeneous metallic plate. It can be fabricated by a low-cost soft lithography technique called two-polymer microtransfer molding. The spectral positions of the mid-infrared (MIR) radiation peaks can be tuned by changing the periodicity of the gratings and the spectral separation between peaks are tuned by changing the mutual angle between the orientations of the two gratings.


Manufacturing Method Of Photonic Crystal, In Sung Park, Tae Ho Lee, Jin Ho Ahn, Rana Biswas, Kristen P. Constant, Kai-Ming Ho, Jae-Hwang Lee Jan 2013

Manufacturing Method Of Photonic Crystal, In Sung Park, Tae Ho Lee, Jin Ho Ahn, Rana Biswas, Kristen P. Constant, Kai-Ming Ho, Jae-Hwang Lee

Iowa State University Patents

A manufacturing method of a photonic crystal is provided. In the method, a high-refractive-index material is conformally deposited on an exposed portion of a periodic template composed of a low-refractive-index material by an atomic layer deposition process so that a difference in refractive indices or dielectric constants between the template and adjacent air becomes greater, which makes it possible to form a three-dimensional photonic crystal having a superior photonic bandgap. Herein, the three-dimensional structure may be prepared by a layer-by-layer method.


Highly Directional Receiver And Source Antennas Using Photonic Band Gap Crystals, Rana Biswas, Gary L. Tuttle, Ekmel Ozbay, Burak Temelkuran, Mihail Sigalas, Kai-Ming Ho Jul 2003

Highly Directional Receiver And Source Antennas Using Photonic Band Gap Crystals, Rana Biswas, Gary L. Tuttle, Ekmel Ozbay, Burak Temelkuran, Mihail Sigalas, Kai-Ming Ho

Iowa State University Patents

A directional antenna made with photonic band gap structures has been presented. The directional antenna is formed with two photonic band gap structures oriented back to back and separated from each other by a distance to form a resonant cavity between the photonic band gap structures. An antenna element is placed in the resonant cavity. The resonant frequency of the cavity is tuned by adjusting the distance between the photonic band gap structures. The resonant cavity can be asymmetrical or symmetrical.


Method Of Making Active Magnetic Refrigerant, Colossal Magnetostriction And Giant Magnetoresistive Materials Based On Gd-Si-Ge Alloys, Karl A. Gschneidner Jr., Alexandra O. Pecharsky, Vitalij K. Pecharsky Jul 2003

Method Of Making Active Magnetic Refrigerant, Colossal Magnetostriction And Giant Magnetoresistive Materials Based On Gd-Si-Ge Alloys, Karl A. Gschneidner Jr., Alexandra O. Pecharsky, Vitalij K. Pecharsky

Iowa State University Patents

Method of making an active magnetic refrigerant represented by Gd5(SixGe1−x)4alloy for 0≦x≦1.0 comprising placing amounts of the commercially pure Gd, Si,and Ge charge components in a crucible, heating the charge contents under subambient pressure to a melting temperature of the alloy for a time sufficient to homogenize the alloy and oxidize carbon with oxygen present in the Gd charge component to reduce carbon, rapidly solidifying the alloy in the crucible, and heat treating the solidified alloy at a temperature below the melting temperature for a time effective to ...