Bilenca Alberto, Cao Jing, Colice Max, Ozcan Aydogan, Bouma Brett, Raftery Laurel, Tearney Guillermo
Harvard Medical School and Wellman Center for Photomedicine, Massachusetts General Hospital, 50 Blossom St., BAR 720, Boston, Massachusetts 02114, USA.
Ann N Y Acad Sci. 2008;1130:68-77. doi: 10.1196/annals.1430.038.
The use of fluorescence radiation is of fundamental importance for tackling measurement problems in the life sciences, with recent demonstrations of probing biological systems at the nanoscale. Usually, fluorescent light-based tools and techniques use the intensity of light waves, which is easily measured by detectors. However, the phase of a fluorescence wave contains subtle, but no less important, information about the wave; yet, it has been largely unexplored. Here, we introduce the concept of fluorescence interferometry to allow the measurement of phase information of fluorescent light waves. In principle, fluorescence interferometry can be considered a unique form of optical low-coherence interferometry that uses fluorophores as a light source of low temporal coherence. Fluorescence interferometry opens up new avenues for developing new fluorescent light-based imaging, sensing, ranging, and profiling methods that to some extent resemble interferometric techniques based on white light sources. We propose two experimental realizations of fluorescence interferometry that detect the interference pattern cast by the fluorescence fields. This article discusses their measurement capabilities and limitations and compares them with those offered by optical low-coherence interferometric schemes. We also describe applications of fluorescence interferometry to imaging, ranging, and profiling tasks and present experimental evidences of wide-field cross-sectional imaging with high resolution and large range of depth, as well as quantitative profiling with nanometer-level precision. Finally, we point out future research directions in fluorescence interferometry, such as fluorescence tomography of whole organisms and the extension to molecular interferometry by means of quantum dots and bioluminescence.
荧光辐射的应用对于解决生命科学中的测量问题至关重要，近期已有在纳米尺度探测生物系统的相关证明。通常，基于荧光的工具和技术利用光波强度，其易于被探测器测量。然而，荧光波的相位包含关于该波的细微但同样重要的信息；然而，这方面在很大程度上尚未得到探索。在此，我们引入荧光干涉测量的概念，以实现对荧光光波相位信息的测量。原则上，荧光干涉测量可被视为一种独特形式的光学低相干干涉测量，它使用荧光团作为低时间相干性的光源。荧光干涉测量为开发新型基于荧光的成像、传感、测距和轮廓分析方法开辟了新途径，这些方法在某种程度上类似于基于白光源的干涉技术。我们提出了两种荧光干涉测量的实验实现方式，用于检测荧光场产生的干涉图样。本文讨论了它们的测量能力和局限性，并将其与光学低相干干涉测量方案的测量能力和局限性进行了比较。我们还描述了荧光干涉测量在成像、测距和轮廓分析任务中的应用，并展示了具有高分辨率和大深度范围的宽场横截面成像以及纳米级精度的定量轮廓分析的实验证据。最后，我们指出了荧光干涉测量未来的研究方向，例如全生物体的荧光断层扫描以及借助量子点和生物发光向分子干涉测量的扩展。
