Laboratoire Matière et Systèmes Complexes

In phononic crystals, the propagation of acoustic waves does not follow the same rules as in standard homogeneous media [1,2]. In particular, absolute band gaps can exist, making phononic crystals promissing candidates for applications such as acoustic filters, silent blocks or waves guides [3]. They can also exhibit resonant tunneling [4] or sub-wavelength imaging [5].

Cristal phononique de bulles

Deux couches d’inclusions gazeuses dans un milieu élastique. Les diamètres sont 78µm, le pas du réseau 200µm.

Among all the components one can think of to create a phononic crystal, the case of air bubbles in a liquid has been shown to be a very promissing choice. Theories predict indeed that crystals with air inclusions in a liquid exhibit the widest band gaps ever reported [6,7]. But the practical implementation is difficult: generating equally sized bubbles arranged on a crystal lattice is not an easy task.

We have designed phononic crystals of bubbles using soft lithography techniques. Transmission measurements confirm the existence of wide and deep minima of transmission [8]. Interestingly, the first minimum is due to the combined effect of Bragg reflections (Bragg gap, BG) and bubble resonances (hybridization gap, HG).

 [1] M. S. Kushwaha, P. Halevi, G. Martinez, L. Dobrzynski, and B. Djafari-Rouhani, Phys. Rev. B 49, 2313 (1994).
 [2] F. R. Montero de Espinosa, E. Jiménez, and M. Torres, Phys. Rev. Lett. 80, 1208 (1998).
 [3] A. Khelif, A. Choujaa, S. Benchabane, B. Djafari-Rouhani, and V. Laude, Applied Physics Letters 84, 4400 (2004).
 [4] F. V. D. Biest, A. Sukhovich, A. Tourin, J. H. Page, B. A. van Tiggelen, Z. Liu, and M. Fink, Europhysics Letters 71, 63 (2005).
 [5] A. Sukhovich, B. Merheb, K. Muralidharan, J. O. Vasseur, Y. Pennec, P. A. Deymier, and J. H. Page, Physical Review Letters 102, 154301 (2009).
 [6] M. S. Kushwaha, B. Djafari-Rouhani, and L. Dobrzynski, Physics Letters A 248, 252 (1998).
 [7] M. Kafesaki, R. S. Penciu, and E. N. Economou, Phys. Rev. Lett. 84, 6050 (2000).
 [8] V. Leroy, A. Bretagne, M. Fink, H. Willaime, P. Tabeling, A. Tourin, Applied Physic Letters 95 171904 (2009). (pdf)

COLLABORATIONS:
 Institut Langevin, Paris, France (A. Bretagne, M. Fink, A. Tourin)
 Laboratoire MMN, Paris, France (P. Tabeling, H. Willaime)