Multifrequency-resolved Hanbury Brown–Twiss effect
The Hanbury Brown–Twiss (HBT) effect holds a pivotal place in intensity interferometry and gave a seminal contribution to the development of quantum optics. To observe such an effect, both good spectral and timing resolutions are necessary. Most often, the HBT effect is observed for a single frequency at a time due to its limitations in dealing with multifrequencies simultaneously, halting and limiting some applications. Here, we report a fast and data-driven spectrometer built with a one-dimensional array of single-photon-sensitive avalanche diodes. We report observing the HBT effect for multiple frequencies at the same time. In particular, we observe the HBT effect for up to five lines of the Ne spectrum, but this can be improved upon to include more lines. Our work represents a major step in making spectral binning and multifrequency HBT more widely available. The technology we present can benefit both classical and quantum applications.