Enhanced Confocal Fluorescence Microscope performance using a differential pinhole

While evaluating the performance of a microscope, one must consider not only the resolution but also SNR. The two criteria are each important to bio-imaging and interdependent such that attempts of optimising one generally tends to degrade the other. Here a novel detection scheme using an alternative pinhole geometry, a differential pinhole, is introduced. The scheme offers enhanced lateral as well as axial resolution resulting in an improved SNR-resolution tradeoff in a confocal fluorescence microscope. Up to 20 % resolution gain in either direction has been achieved and the performance enhancement has been demonstrated through computer simulations. The new detection scheme if used in conjunction with annular lens apertures could see further resolution gains.