Supervisor: Badreddine ASSOUAR
The laboratory began working on the research theme of phononic crystals and acoustic metamaterials in 2006. These are artificial structures or materials with frequency band gaps for elastic or acoustic waves and overall are called: band gaps. The idea underpinning our research was to propose and then study new concepts and structures using both theoretical/digital and experimental approaches. We study locally resonant phononic crystals (LRPC) operating in sonic and hypersonic regimes with a view to using the subwavelengths inherent to LRPCs to develop low frequency (sonic insulation, insulation in aerospace and aeronautic systems, etc.), and high frequency applications (highly selective filtering, waveguiding, demultiplexing, sensors, etc.). Such structures may be micro- or nano-structured for high frequency applications or macroscopic (millimetric) for use at low frequencies. This homothety regarding dimensions enables the study of the physical phenomena and mechanisms which underpin these artificial materials in different frequency regimes and also the effective use of their unique properties which are only found in nature (negative refractive index, negative effective mass density, negative elastic modulus, etc.).
Fig.1: Example of a plate-type metamaterial with cylinders (resonators) made of silicone rubber and tungsten.
There are two branches to these studies. Firstly we study LRPC or bi-dimensional acoustic metamaterials based on cylinders or included or incorporated into thin plates. Figure 1 shows an example made up of a thin plate of aluminium on which cylinders made of silicone rubber and tungsten are arranged. These macroscopic structures have band gaps ranging from 600 Hz to 3kHz according to geometric parameters. Figure 2 gives an example of experimental measurements made using Doppler vibrometry in waveguides created within these metamaterials where we used the subwavelength regime to both confine and guide these very low frequency elastic waves.
Fig.2: Experimental measurements made using Doppler vibrometry in two waveguides of different widths created in a plate-type metamaterial.
Alongside this work we are also studying how to effectively use the subwavelength regime for high frequency (>GHz) applications with a view to creating single-mode cavities and mono-mode waveguides simply by introducing a defect into the structure.
1. M. B. Assouar, M. Senesi, M. Oudich & al. Appl. Phys. Lett., 101 (2012) 173505.
2. M. Oudich & M. B. Assouar. Journal of Applied Physics, 112 (2012) 104509.
3. M. B. Assouar & M. Oudich. Applied Physics Letters, 100 (2012) 123506.
4. Y. Li, Z. Hou, M. Oudich & M. B. Assouar. J. Appl. Phys., 112 (2012) 023524.
5. M. Oudich & M. B. Assouar. Journal of Applied Physics, 111 (2012) 014505.
6. M. Oudich, M. Senesi, M. B. Assouar, M. Ruzzene & al. Phys. Rev. B, 84 (2011) 165136.
7. M. B. Assouar & M. Oudich. Applied Physics Letters, 99 (2011) 13505.
8. D. Bria, M. B. Assouar, M. Oudich, Y. Pennec & al. J. Appl. Phys., 109 (2011) 014507.
9. M. Oudich, M. B. Assouar & Z. Hou. Applied Physics Letters, 97 (2010) 193503.
10. M. Oudich, Y. Li, M. B. Assouar & Z. Hou. New Journal of Physics,12 (2010) 083049.
11. Y. Li, Z. Hou, X-J Fu & M. B. Assouar. Chinese Physics Letters, 27 (2010) 074303.
12. V. Laude, M. B. Assouar & Z. Hou. IEEE TUFFC , 57 (2010) 1649.
13. Z. Hou & M. B. Assouar. Springer Science and Business Media, 26 (2010) 325.
14. Z. Hou & M. B. Assouar. Journal of Physics D: Applied Physics, 42 (2009), 085103.
15. Z. Hou & M. B. Assouar. Journal of Physics D: Applied Physics, 41 (2008) 215102.
16. Z. Hou & M. B. Assouar. Journal of Physics D: Applied Physics, 41 (2008) 095103.
17. Z. Hou & M. B. Assouar. Physics Letters A, 372 (2008), 2091.
18. M. B. Assouar, B. Vincent, H. Moubchir. IEEE TUFFC, 55 (2008) 273.