Hu Xinhua, Chan C T, Zi Jian
Department of Physics, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China.
Phys Rev E Stat Nonlin Soft Matter Phys. 2005 May;71(5 Pt 2):055601. doi: 10.1103/PhysRevE.71.055601. Epub 2005 May 5.
We present a type of sonic crystal composed with an array of two-dimensional Helmholtz resonators, which in the long-wave regime have both a high relative acoustic refractive index n and at the same time, a small acoustic impedance Z mismatch with air for airborne sound. We analyze the n and Z of such sonic crystals by finite-difference time-domain simulations, and by mapping our results to a corresponding electromagnetic (EM) model, and we find that our Helmholtz resonant sonic crystal has a bigger effective magnetic permeability mu than the conventional rigid-cylinder sonic crystal in its EM counterpart. As a result, a thin convergent lens with very good focusing effect is demonstrated based on our crystal.
我们展示了一种由二维亥姆霍兹谐振器阵列组成的声子晶体，在长波区域，它具有高相对声折射率n，同时对于空气传播的声音而言，与空气的声阻抗Z失配较小。我们通过时域有限差分模拟分析了这种声子晶体的n和Z，并将结果映射到相应的电磁（EM）模型，我们发现我们的亥姆霍兹谐振声子晶体在其电磁对应物中比传统的刚性圆柱体声子晶体具有更大的有效磁导率μ。因此，基于我们的晶体展示了一种具有非常好聚焦效果的薄会聚透镜。
