基于声学超透镜的亚波长分辨率光声显微成像关键技术研究

The early diagnosis and identification of cardiovascular vulnerable plaque or cancer is a major issue related to the overall national health. Photoacoustic imaging technology relys on its high-quality imaging capabilities and high degree of biosecurity has been shows the advantage in this major issue. The development trend of photoacoustic microscopy imaging required to achieve the subwavelength ultra-high resolution imaging of microtissue, However, the current technology can not break through the "diffraction limit" in photoacoustic signal far-field imaging. It is difficult to achieve subwavelength resolution. The project research the transmitting law of evanescent wave proceed with the photoacoustic signal transmission medium, using the technical advantage of acoustic metamaterials in the near-field acoustic imaging, making acoustic superlens technology research suitable for photoacoustic microscopy near-field imaging , try using acoustic superlens change the current collection method of photoacoustic signal , trying to use acoustic superlens negative refraction near-field acoustic imaging characteristics to solving the problem of evanescent wave transmission and the bottleneck problem of photoacoustic signal "diffraction limit" in the development of photoacoustic imaging resolution technology. This project research the technology of near-field photoacoustic imaging resolution based on the negative refractive properties of acoustic superlens. lay the foundation of the near-field acoustic imaging mode research of photoacoustic microscopy imaging.

心脑血管易损斑块早期辨识，恶性肿瘤早期诊断与辨识是关系整体国民健康的重大课题，光声成像技术凭借优质的成像能力和高度的生物安全性已经在这个重大课题中显现了优势。光声显微成像发展趋势要求实现微小组织的亚波长超高分辨率成像，然而当前的分辨率技术无法突破目前光声信号远场成像中“衍射极限”的制约，很难实现亚波长分辨率。本项目从光声信号传输的介质入手研究倏逝波的传输规律，借鉴声学超材料在近场声成像的技术优势，进行适合于光声显微近场成像的声学超透镜技术研究，尝试利用声学超透镜改变当前的光声信号采集方法，试图用声学超透镜负折射率近场声成像特性解决倏逝波传输问题，解决目前光声成像分辨率技术发展中光声信号“衍射极限”的瓶颈问题。本项目是进行基于声学超透镜负折射率特性的近场光声成像分辨率技术研究，为光声显微成像的近场声成像方式研究奠定基础。

恶性肿瘤早期诊断与辨识是关系整体国民健康的重大课题，光声成像技术凭借优质的成像能力和高度的生物安全性已经在这个重大课题中显现了优势。光声显微成像发展趋势要求实现微小组织的亚波长超高分辨率成像，然而当前的分辨率技术无法突破目前光声信号远场成像中“衍射极限”的制约，很难实现亚波长分辨率。本项目的研究核心是进行声学超材料设计与分析。首先完成了声学超材料的结构、声阻抗等多参数对声学超材料性能的影响以及声学超材料带隙特性调制规律研究。其次，在研究中考虑到结构的优化设计及其参数变化(如复周期或多重周期结构、准周期结构、分形结构以及复杂散射体形状等)对带隙的调控影响研究。同时,还进行了倏逝波传输模式与声学超材料振动微单元本征模式的耦合效应研究，通过有限结构体的声学超材料中光声信号倏逝波传播与微单元本征模式的耦合效应研究，考察微单元本征局域共振模式的激发、声学倏逝波本征模式相耦合、分析增强光声倏逝波信号的规律，使得图像细节的倏逝波有效的传输，结合医学显微组织检测的需求，分析参数调节规律，探索基于有限结构体超材料的亚波长分辨率成像方法。对于我国光声显微成像技术的发展能起到一定的促进作用,并为相关设备的研发提供较为有力的理论支撑,具有一定的科学价值。