1. Apparatus for detecting a pulse of light energy comprising: at least one pixel for accumulating a first photocharge at a first sample time, said at least one pixel also accumulating a second photocharge at a second sample time; means for storing said first photocharge and said second photocharge; means for differentially combining said first photocharge and said second photocharge to detect said pulse of light energy, said differentially combining means including at least two sample and hold circuits for sampling said first photocharge and said second photocharge respectively, at least one of said two sample and hold circuits being clocked at one-half a frequency at which said storing means is clocked; and a single substrate upon which said at least one pixel for accumulating said first photocharge, said at least one pixel for accumulating said second photocharge, said storing means and said differentially combining means are formed.