基于宽带受激辐射的纳米光学成像技术研究

Optical nanoscopy with a resolution beyond the conventional diffraction barrier, a big advance in biomedical optical imaging technologies, will certainly give rise to vital breakthrough in biomedical researches. However, the performance of existing nanoscopy is still need to be improved, including its imaging speed, and feasibility for non-fluorescent samples. The project introduces stimulated emission of wideband light for optical superresolution, using spectral domain optical coherence tomography for parallel high-sensitive signal detection. The proposed novel optical nanoscopy can achieve fast optical imaging at a resolution of sub-hundred nanometers for both non-fluorescent chromophores and fluorescent samples. Based on theoretical analysis, we design and build the proposed system, test the performance of the constructed system and conduct several related biomedical researches. The implementation of the project not only realizes nanoscopy of non-fluorescent samples for the first time, laying foundation for further development of label-free optical nanoscopy and extending its application in biomedical researches, but also provides a novel concept for enhancement of imaging speed for optical nanoscopy.

超衍射极限的纳米光学成像技术，是生物医学光学成像技术的重要进展，必将推动生物医学研究的重大突破。然而，现有纳米光学成像技术在性能上仍存在不足，如成像速度尚需提高、不能针对非荧光样品等。本项目提出基于宽带光受激辐射的纳米超分辨光学成像机制，引入基于谱域光学相干层析技术的高灵敏度并行探测方法，以期实现对非荧光色团和常规荧光样品的亚百纳米分辨的快速成像。本项目在理论分析的基础上，设计并搭建纳米分辨光学成像系统，测试该新型纳米光学成像技术在实际中的成像效果，并开展相关的生物医学应用研究。本项目的实施将首次实现对于非荧光样品的超分辨显微成像，为非荧光标记纳米光学显微术的发展奠定基础，扩大纳米光学成像技术在生物医学研究中的应用，同时也为显著提高纳米光学成像技术的成像速度提供一种全新的思路。

本项目从样品特性、光场调控、信号探测三方面对成像系统的分辨率、信噪比、成像速度等进行了全局优化，发展了纳米光学超分辨成像技术。基于谱域OCT的相干探测与泵浦探测下的调制解调方法，实现了微弱受激辐射增量信号的高灵敏度获取。建立了基于受激辐射信号的OCT成像方法, 在实现传统散射成像的同时, 实现荧光样品和非荧光样品的分子成像。此外，优化了谱域OCT系统的性能。搭建了集成的纳米光学显微系统，并编写了仿真软件和硬件控制及数据处理软件，发展了几种提高系统工作稳定性和成像速度的方法，并推广到实际应用中，实现对多种对生物和材料样品的超分辨光学成像。同时，研制了系列在体成像OCT探头，发展了OCT功能成像技术，开展了生物医学成像应用研究。项目执行期间取得授权中国发明专利23件，中国软件著作权1件，并申请中国发明专利11件；发表学术论文74篇，包括Physical Review Letters, ACS Nano, Optica, Journal of Cerebral Blood Flow & Metabolism等重要国际期刊的论文。