Hanbury Brown–Twiss effect and thermal light ghost imaging: A unified approach

We compare the Hanbury Brown--Twiss (HBT) and the thermal light ghost imaging schemes in both near and far fields. Both effects arise as a result of the intensity fluctuations of the thermal light and we find that the essential physics behind the two effects is the same. The difference however is that, in the ghost imaging, large number of bits information of an object needs to be treated together, whereas, in the HBT, there is only one bit information required to be obtained. In the HBT experiment far field is used for the purpose of easy detection, while in the ghost image experiment near (or not far) field is used for good quality image.