Holey structured periodic arrays for subwavelength resolution

The resolution of a conventional imaging system is limited to half the wavelength by natural diffraction limit. To overcome the resolution limit it is important to get the information from the decaying evanescent waves, which is not possible with the conventional imaging system. This paper discusses holey structure metamaterial for achieving resolution beyond the diffraction limit. We experimentally demonstrate a subwavelength resolution of そ/η in the ultrasonic regime. Then a practical and cost-effective way of achieving this by plastic tubes is also demonstrated.