Luminescence-based molecular scale logic circuits

Abstract We show how a half-adder logic circuit can be implemented on one molecule for a molecule exhibiting both S 1 →S 0 and S 2 →S 0 fluorescence. This is achieved by using both one photon S 0 →S 1 excitation and consecutive S 1 →S 2 excitation and establishing logic thresholds by utilizing the laser-induced photoquenching process. We present results pertaining to rhodamine and azulene molecules, in which, for the first time, an all optical half-adder logic circuit is implemented.