  This experiment reports a nontrivial third-order temporal correlation of
chaotic-thermal light in which the randomly radiated thermal light is observed
to have a 6-times greater chance of being captured by three individual
photodetectors simultaneously than that of being captured by three
photodetectors at different times (separated by the coherent time of
pseudo-thermal light), indicating a "three-photon bunching" effect. The
nontrivial correlation of thermal light is the result of multi-photon
interference.
