To get an information "bit" out of a photon activity, one could perhaps compare the phase angle of two photons.
Suppose that there was a reference photon in a known location, this photon energy would have a specific frequency and amplitude, then you would take another photon that was either in phase or out of phase with the reference photon and you would compare them and detect the amount of the difference in their phase angles.
The presence or absence of a specified phase angle would determine the "0" or "1" of the bit.
If you were only able to detect the difference between the photon phase angles to a one degree resolution then you would have the ability to detect only 360 "bits" of information per photon "storage" area.
If the photons were in the far ultraviolet or x-ray frequencies then their wavelength would be very short and you could pack a lot of information into a cubic millimeter area.

Since there are many mathematicians on the HZ, they would surely be able to figure out how many "bits" of information could be "stored" in this type of photon matrix at any specific phase angle resolution.

The technology for such a thing is not extremely far beyond our present technology.

Link to nanophotonics:

http://www.almaden.ibm.com/st/exploratory_technology/nanophotonics/index.shtml

Johannes