| 研究実績の概要 |
Our group is specialized in acoustic metamaterials and ultrafast phononics from audio to GHz frequencies. In particular, we have experience in picosecond ultrasonics and plasmonics in nanostructures, plasphonics, acoustic metamaterials, surface acoustic wave visualization with ultrashort optical pulses, ultrafast electronic and thermal diffusion, and nanoscale phonon detection using atomic force microscopy.
Research highlights have been as follows. First demonstration of: 1) surface acoustic wave real time imaging on solids, 2) interferometic detection of ultrafast surface motion of solids, 3) surface wave real time imaging on phononic crystals, 4) picosecond echo detection on semicondutor quantum wells, 5) picosecond shear phonon pulse detection in solids, 6) picosecond tracking of phonon pulses in nanostructures, 7) giant extraordinary transmission of acoustic waves in zero-mass metamaterials, 8) realisation of efficient air-to-water acoustic transmission, and demonstration of extraordinary transmission bulk longitudinal waves in solids.
|
| 現在までの達成度 (区分) |
現在までの達成度 (区分)
2: おおむね順調に進展している
理由
1. Metamaterial-based acoustic microscopy: With our scanning extraordinary-transmission-based acoustic microscope for deep subwavelength imaging, we have developed a theory of the phase response, showing that a pi phase change occurs as the frequency is scanned. This should help identify and image properties other than just the topography.
2. Metasurface for air-water acoustic transmission: We have experimented on our metasurface system of masses and springs of area 15 cm x 15 cm to achieve enhanced acoustic transmission from water to air, with an enhancement achieved equal to 16000 in intensity.
3. Metapillars and metaplates for broadband multimode vibration isolation: A perfect-bandgap metarod was demonstrated and extraordinary transmission in a nanorod demonstrated, and papers on these two studies were published, one in Applied Physics Letters and one in Sci. Adv., respectively.
4. Flexural metaplates: We have identified the behavior of metaplates with square- or triangular-lattice spirally-arranged slits as double chiral structures, and are preparing a journal paper on this subject.
5. Phoxonic metamaterials for new physics and applications: We have decided to combine microwave engineering with kHz acoustics to achieve our goals, and are now conducting simulations on a demonstrated double-negative electromagnetic metamaterial by the inclusion of an extra silicone layer for rendering it a phoxonic metamaterial.
|
| 今後の研究の推進方策 |
1. Metamaterial-based acoustic microscopy: With our scanning extraordinary-transmission-based acoustic microscope for deep subwavelength imaging, we will develop an analytical theory of the system based on the sonic Drexhage effect.
2. Metasurface for air-water acoustic transmission: We will experiment on a new floating metasurface system of masses and springs of area 50 cm x 50 cm in a swimming pool, and seek practical applications.
3. Metapillars and metaplates for broadband multimode vibration isolation: We will make a tapered metarod for broadband operation that can cut sound propagation in all modes.
4. Flexural metaplates: We will continue to write up our simulation results as a journal paper.
5. Phoxonic metamaterials for new physics and applications: We will, by simulation, attempt to demonstrate a triple negative phoxonic metamaterial based on a microwave double-negative metamaterial combined with a kHz acoustic negative-density metamaterial.
|
