2016 Fiscal Year Annual Research Report
Subwavelength acoustic imaging using kHz-GHz extraordinary transmission
| Project/Area Number |
16F16786
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| Research Institution | Hokkaido University |
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Principal Investigator |
O・B Wright 北海道大学, 工学研究院, 教授 (90281790)
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| Co-Investigator(Kenkyū-buntansha) |
DEVAUX THIBAUT 北海道大学, 工学研究院, 外国人特別研究員
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| Project Period (FY) |
2016-11-07 – 2019-03-31
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| Keywords | extraordinary / transmission / metamaterial / audio / ultrasonics / sound |
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| Outline of Annual Research Achievements |
We have demonstrated an Extraordinary-Transmission (ET)-based scanning acoustic microscope based on membrane resonance (MR) in the audio (up to 20 kHz) range (wavelength ~1-10 mm) with deeply sub-wavelength (<lamba/30) resolution. The microscope has a plastic membrane of diameter around 1 cm working at around 1000 Hz. We confirmed operation for topography measurement up to 15 mm distance. Linear scans were made of several materials to confirm lambda/20 resolution. We have also done simulations on GHz ET of longitudinal waves in nanoscale silicon bridges and confirmed the principle works with grooves at the input side. Similar simulations of GHz ET for surface acoustic waves have also been successful.
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| Current Status of Research Progress |
Current Status of Research Progress
2: Research has progressed on the whole more than it was originally planned.
Reason
We constructed and tested the audio version of our ET microscope and verified the operation. In addition GHz simulations of ET in solids was successful.
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| Strategy for Future Research Activity |
ET-based microscope: We will demonstrate an ET-based scanning acoustic microscope with two-dimensional imaging. We hope to improve the lateral resolution to lambda/30. Extension to multi-tip scanning for rapid operation and in-liquid operation will be sought.
SAW investigations: Based on the geometries selected, we intend to fabricate structures in Si using FIB (focused ion beam) milling as well as SAW imaging experiments.
Longitudinal wave investigations: Guided by new simulations on more realistic materials, we will use ~100 GHz longitudinal waves to excite thin film structures based on tungsten-film transducers and silica or aluminium films. Near-field ET-based GHz acoustic sensing will be attempted for longitudinal waves, with experimental testing of the detection of adsorbed nanoparticles.
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