基于负折射率声透镜的亚波长分辨率光声实时成像方法

基于负折射率材料的信号处理技术为光声图像的研究提供了新的思路。光声成像是一种全新的非破坏性生物光子技术,是一种基于生物组织内光吸收差异的成像方法。然而,当前的光声成像方法主要依靠传感器扫描工作,而传感器阵列有其固有的缺点,导致实时性较差,因此,普通的光声成像方式具有一定的局限性。但是,利用具有负折射率的声透镜特性(如聚焦、滤波、定向等)构成的成像方式可以解决普通光声成像中的这些局限性问题。本文在对负折射率声透镜的负质量响应和负折射率成像进行优势分析后,提出了利用声透镜改变当前扫描成像的方法。模拟分析实验结果表明,所设计的声透镜直接成像方案达到了预期效果,透镜成像后像点的声压分布与吸收体原始的声压分布基本一致。此外,0.6倍波长的实验图像结果说明本文实现了亚波长的光声成像效果。

Direct and real-time sub-wavelength resolution photoacoustic imaging method based on acoustic lens with negative refractive index

The signal processing technology based on material with negative refractive index provides researchers with the latest ideas.As a new nondestructive bio-photonic technology,photoacoustic tomography is a kind of imaging method based on the differences of optical absorption within the biological organization.However,photoacoustic tomography by the scanning sensor or by the sensors array at present has its inherent disadvantages that may lead to poor real-time performance and high cost in the imaging process.The characteristics of acoustic lens with negative refractive index such as focusing,filtering and directional control on acoustic wave,are very suitable for solving the problem in photoacoustic tomography.With an analysis on the nega-tive quality response of acoustic lens and the advantages of negative refractive imaging,we proposed an approach using the lens to change the current photoacoustic imaging methods.The experiment showed that the imaging effectiveness of photoacoustic tomography by the designed lens is very impressive that the pressure distribution of the absorber is basically consistent with the image of the absorber.In addition,the result of 0.6 times wavelength in the experimental image is demonstrated on sub-wave-length photoacoustic imaging through the lens designed in this work.