Good survey of the literature of photon correlations for spectroscopy, imaging, etc. The field would benefit from the bundler:

To date, SPDC light is the most common light source in quantum-optics experiments, in general, and a frequent one for quantum-based imaging and sensing schemes, in particular.

Interesting further references:

1. [32] quantitative microscopy for fluorescent microscopes.
2. [33-36] counting by photon statistics (CoPS).

1. [51] Small pixelated detector array.
2. [20, 52-53] n-photon correlation for multiply excited states.
3. [64] Temporal-frequency correlations.
4. [6, 66] single-photon pixelated detectors for photon correlation spectrometers
5. [67-69] enhanced isolation of SPDC photon pairs by multidimensional spectrotemporal-correlation measurements.
6. [70-72] Metrology with multiphoton states.
7. [74] Optical centroid measurements.