Wide-field Intensity Fluctuation Imaging

The temporal intensity fluctuations contain important information about the light source and light-medium interaction and are typically characterized by the intensity autocorrelation function, [Formula: see text]. The measurement of [Formula: see text] is a central topic in many optical sensing applications, ranging from stellar intensity interferometer in astrophysics, to fluorescence correlation spectroscopy in biomedical sciences and blood flow measurement with dynamic light scattering. Currently, [Formula: see text] at a single point is readily accessible through high-frequency sampling of the intensity signal. However, two-dimensional wide-field measurement of [Formula: see text] is still limited by camera frame rates. We propose and demonstrate a 2-pulse within-exposure modulation approach to break through the camera frame rate limit and obtain the quasi [Formula: see text] map in wide field with cameras of only ordinary frame rates.