The optimal system for sub-wavelength point source localization

Sub-wavelength super-resolving systems are known to waste light. The aim of this communication is to analyze what is the optimal resolving system for sub-wavelength structures. Two criteria for optimization are considered whereas the optimization analysis is carried in the spirit of entropy consideration: Uniform light efficiency and minimal number of photons required for the resolving process. For large number of possible positions, the first process converges to the second one. A Gedanken experiment showing that the optimal positioning estimator can be implemented is suggested. (C) 2001 Published by Elsevier Science B.V.