纳米分辨率的扫描探针光声显微镜

With the development of life science and nano technology, there is a stronger demand on detection of physical/chemical properties and function with nano resolution more than topography imaging for soft cells and hard nano-devices, which have complex 3D spatial distribution of physical and chemical properties and nano feature sizes. Photoacoustic (PA) effect can offer the information of sample’s optical, thermal, thermal-elastic and elastic properties, while SPM can offer a near-field scanning detection platform with ultra-high resolution beyond Rayleigh diffraction limit. It’s possible to realize the detection of physical/chemical properties and function with nano resolution from combination of PA effect and SPM. In this proposal, based on the theoretical study of contrast mechanism of PA imaging with nano resolution, SPM will be integrated with multi-wavelength pulsed lasers with high repetition rate, delay trigger element, home-made optical fiber guide and sample stage to implement synchronization of laser pulse and SPM probe scanning and get data on acoustic frequency dimension using frequency sweeping and phase locking. Finally, the scanning probe photo-acoustic microscopy with nano resolution will be developed, accomplishing imaging and detection of structure, physical/chemical properties and function of soft cells and hard nano-devices as representative samples.

随着生命科学和纳米技术的发展，物理化学特性在三维空间有复杂分布、且精细结构特征尺寸在纳米尺度的细胞“软”组织和纳米器件“硬”材料已不再局限于形貌检测，而是都有实现纳米分辨率的物性和功能检测的强烈需求。光声效应可以综合反映材料的吸收光谱、热学特性、热弹特性和弹性等性质，扫描探针显微镜（SPM）可以提供高分辨率的突破衍射极限的近场扫描检测平台，因此将两者结合有可能实现纳米分辨率的材料物性和功能检测。本申请拟以纳米分辨率光声成像的反差机理理论研究为基础，融合高重复频率的多波长脉冲激光源、触发延时控制单元、自制光纤导光系统、自制试样台与SPM系统，实现激光脉冲与SPM的二维高速扫描的同步，发展扫频锁相的技术以在声频率维度上获取光声信号，建成纳米分辨率的扫描探针光声显微镜，并实现 “软”的细胞组织和“硬”的纳米器件两类具有纳米结构的代表性试样的结构、物性和功能检测。

形貌、结构和半导体材料的非辐射复合特性的同时、原位、高分辨率检测至今仍是集成电路检测的一大难题，脉冲光声扫描检测成像是可能的解决方案之一。本项目提出了全新的近场光声检测理论和扫描近场光声显微术，在理论上探讨了分别在近场和远场时半导体和金属的光声源激发机制，探讨了多层复杂介质中光声源特征和传播的理论，以及微弱声信号的接收、精准标定与成像方法；研制了扫描近场光声显微镜以及非平面声场的光学CT成像和标定系统，实现了集成电路的形貌、结构和载流子动态特性的同时、原位、高分辨率检测。项目研究成果也同样适用于闪烁体和激光晶体的特性检测，可服务于高能辐射探测领域和高性能激光研发领域。