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Materials Science and Engineering

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Air Force Institute of Technology

Faculty Publications

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2017

Articles 1 - 5 of 5

Full-Text Articles in Engineering

Use Of A Novel Infrared Wavelength-Tunable Laser Mueller-Matrix Polarimetric Scatterometer To Measure Nanostructured Optical Materials, Jason C. Vap, Stephen E. Nauyoks, Michael R. Benson, Michael A. Marciniak Oct 2017

Use Of A Novel Infrared Wavelength-Tunable Laser Mueller-Matrix Polarimetric Scatterometer To Measure Nanostructured Optical Materials, Jason C. Vap, Stephen E. Nauyoks, Michael R. Benson, Michael A. Marciniak

Faculty Publications

Nanostructured optical materials, for example, metamaterials, have unique spectral, directional, and polarimetric properties. Samples designed and fabricated for infrared (IR) wavelengths have been characterized using broadband instruments to measure specular polarimetric transmittance or reflectance as in ellipsometry or integrated hemisphere transmittance or reflectance. We have developed a wavelength-tunable IR Mueller-matrix (Mm) polarimetric scatterometer which uses tunable external-cavity quantum-cascade lasers (EC-QCLs) to tune onto and off of the narrowband spectral resonances of nanostructured optical materials and performed full polarimeteric and directional evaluation to more fully characterize their behavior. Using a series of EC-QCLs, the instrument is tunable over 4.37-6.54 μm wavelengths …

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Modeling Micro-Porous Surfaces For Secondary Electron Emission Control To Suppress Multipactor, James M. Sattler, Ronald Coutu Jr., Robert A. Lake, Tod V. Laurvick, Tyson C. Back, Steven. B. Fairchild Aug 2017

Modeling Micro-Porous Surfaces For Secondary Electron Emission Control To Suppress Multipactor, James M. Sattler, Ronald Coutu Jr., Robert A. Lake, Tod V. Laurvick, Tyson C. Back, Steven. B. Fairchild

Faculty Publications

This work seeks to understand how the topography of a surface can be engineered to control secondary electron emission (SEE) for multipactor suppression. Two unique, semi-empirical models for the secondary electron yield (SEY) of a micro-porous surface are derived and compared. The first model is based on a two-dimensional (2D) pore geometry. The second model is based on a three-dimensional (3D) pore geometry. The SEY of both models is shown to depend on two categories of surface parameters: chemistry and topography. An important parameter in these models is the probability of electron emissions to escape the surface pores. This probability …

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On-Chip, High-Sensitivity Temperature Sensors Based On Dye-Doped Solid-State Polymer Microring Lasers, Lei Wan, Hengky Chandrahalim, Cong Chen, Qiushu Chen, Ting Mei, Yuji Oki, Naoya Nishimura, Lingjie Jay Guo, Xudong Fan Aug 2017

On-Chip, High-Sensitivity Temperature Sensors Based On Dye-Doped Solid-State Polymer Microring Lasers, Lei Wan, Hengky Chandrahalim, Cong Chen, Qiushu Chen, Ting Mei, Yuji Oki, Naoya Nishimura, Lingjie Jay Guo, Xudong Fan

Faculty Publications

We developed a chip-scale temperature sensor with a high sensitivity of 228.6 pm/°C based on a rhodamine 6G (R6G)-doped SU-8 whispering-gallery mode microring laser. The optical mode was largely distributed in a polymer core layer with a 30 μm height that provided detection sensitivity, and the chemically robust fused-silica microring resonator host platform guaranteed its versatility for investigating different functional polymer materials with different refractive indices. As a proof of concept, a dye-doped hyperbranched polymer (TZ-001) microring laser-based temperature sensor was simultaneously developed on the same host wafer and characterized using a free-space optics measurement setup. Compared to TZ-001, the …

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Electron Paramagnetic Resonance Study Of Neutral Mg Acceptors In Β-Ga2O3 Crystals, Brant E. Kananen, Larry E. Halliburton, Elizabeth M. Scherrer, K. T. Stevens, G. K. Foundos, K. B. Chang, Nancy C. Giles Aug 2017

Electron Paramagnetic Resonance Study Of Neutral Mg Acceptors In Β-Ga2O3 Crystals, Brant E. Kananen, Larry E. Halliburton, Elizabeth M. Scherrer, K. T. Stevens, G. K. Foundos, K. B. Chang, Nancy C. Giles

Faculty Publications

Electron paramagnetic resonance (EPR) is used to directly observe and characterize neutral Mg acceptors (Mg0Ga) in a β-Ga2O3 crystal. These acceptors, best considered as small polarons, are produced when the Mg-doped crystal is irradiated at or near 77 K with x rays. During the irradiation, neutral acceptors are formed when holes are trapped at singly ionized Mg acceptors (Mg−Ga). Unintentionally present Fe3+ (3d5) and Cr3+ (3d3) transition-metal ions serve as the corresponding electron traps. The hole is localized in a nonbonding p orbital on a threefold-coordinated oxygen ion …

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Defect-Related Optical Absorption Bands In Cdsip2 Crystals, Elizabeth M. Scherrer, Brant T. Kananen, Eric M. Golden, F. Kenneth Hopkins, Kevin T. Zawilski, Peter G. Schunemann, Larry E. Halliburton, Nancy C. Giles Mar 2017

Defect-Related Optical Absorption Bands In Cdsip2 Crystals, Elizabeth M. Scherrer, Brant T. Kananen, Eric M. Golden, F. Kenneth Hopkins, Kevin T. Zawilski, Peter G. Schunemann, Larry E. Halliburton, Nancy C. Giles

Faculty Publications

When used as optical parametric oscillators, CdSiP2 crystals generate tunable output in the mid-infrared. Their performance, however, is often limited by unwanted optical absorption bands that overlap the pump wavelengths. A broad defect-related optical absorption band peaking near 800 nm, with a shoulder near 1 µm, can be photoinduced at room temperature in many CdSiP2 crystals. This absorption band is efficiently produced with 633 nm laser light and decays with a lifetime of ∼0.5 s after removal of the excitation light. The 800 nm band is accompanied by a less intense absorption band peaking near 1.90 µm. Data …

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