A non-invasive optical measurement system comprises an optical source for generating source light, and an interferometer for splitting the source light into sample light and reference light, delivering the sample light into an anatomical structure, resulting in physiological-encoded signal light that exits the anatomical structure, and combining the signal light and the reference light into at least three phase-modulated interference light patterns. The optical path lengths of the respective source light and sample light match within a coherence length of the source light. The system further comprises at least three optical detectors configured for respectively detecting the interference light patterns, and a processor configured for determining a time-lapsed complex field of the signal light based on the interference light patterns, determining a decorrelation speed of the time-lapsed complex field of the signal light, and identifying a physiological event in the anatomical structure based on the determined decorrelation speed of the signal light.
