Acoustic Focusing Imaging Characteristics Based on Double Negative Locally Resonant Phononic Crystal

Abstract

To achieve high-efficiency and high-resolution acoustic focusing, we used artificial periodic acoustic structures composed of cell arrays to manipulate the acoustic transmission wave front, and used finite element software to simulate the acoustic field characteristics. We found that when focuses generated by arc-shaped acoustic excitation sources are incident on one side of the model, the energy will be localized within the structure to reduce its transmission loss, and then the high-resolution emission focus will be generated on the other side of the model. The magnitude of the acoustic pressure at the focus point will change with the frequency of the incident acoustic wave and will reach an extreme value at the resonant frequency. In addition, we explored the acoustic transmission characteristics of structures at different widths and found that it is only necessary to increase the width of the model by an integer multiple of half a wavelength to achieve low loss focusing effects at various distances. The acoustic phenomena studied in this paper may provide new methods for the application of photoacoustic signal detection, ultrasound medical imaging and ultrasonic nondestructive testing.

Keywords

• Acoustic focusing
• artificial structures
• local resonance