Chen Yifan, Tsao Chieh, Cobb-Bruno Colburn, Utzat Hendrik
Opt Express. 2025 Feb 10;33(3):6514-6525. doi: 10.1364/OE.550522.
The inherent non-linearity of intensity correlation functions can be used to spatially distinguish identical emitters beyond the diffraction limit, as achieved, for example, in super-resolution optical fluctuation imaging (SOFI). Here, we propose a complementary concept based on spectral correlation functions, termed spectral fluctuation super-resolution (SFSR) imaging. Through theoretical and computational analysis, we show that spatially resolving time-frequency correlation functions in the image plane can improve the imaging resolution by a factor of 2 in most cases and up to twofold for strictly two emitters. This improvement is achieved by quantifying the degree of correlation in spectral fluctuations across the spatial domain. Experimentally, SFSR can be implemented using a combination of interferometry and photon-correlation measurements. The method works for non-blinking emitters and stochastic spectral fluctuations with arbitrary temporal statistics. This suggests its utility in super-resolution microscopy of quantum emitters at low temperatures, where spectral diffusion is often more pronounced than emitter blinking.
强度相关函数固有的非线性可用于在衍射极限之外对相同的发射体进行空间分辨，例如在超分辨率光学涨落成像（SOFI）中所实现的那样。在此，我们提出一种基于光谱相关函数的互补概念，称为光谱涨落超分辨率（SFSR）成像。通过理论和计算分析，我们表明在像平面中对时频相关函数进行空间分辨在大多数情况下可将成像分辨率提高2倍，对于严格的两个发射体可提高至两倍。这种提高是通过量化跨空间域的光谱涨落中的相关程度来实现的。在实验上，SFSR可使用干涉测量和光子相关测量的组合来实现。该方法适用于非闪烁发射体以及具有任意时间统计特性的随机光谱涨落。这表明它在低温下量子发射体的超分辨率显微镜成像中具有实用性，在低温下光谱扩散通常比发射体闪烁更为显著。
