Picosecond cascadable inverter gate using second harmonic pumping

The possibility to realize one all-optical picosecond inverter or one NOR gate has been demonstrated several times. However, the difficult problem of cascading this device (i.e. to use one gate output for driving another gate) is still open. We report in this communication a first step towards simply cascadable logical NOR gates by demonstrating the possible operation of an all-optical inverter which uses an intermediate frequency doubling of the input signal. This implies that a cascadable all-optical NOR gate operating in an “effective” one-wavelength mode (i.e. with an intermediate frequency doubling) is possible. Experiments are carried out on a II–VI compound, namely CdSe, at liquid nitrogen temperature. The inverter operation is investigated around the wavelength 673 nm. The switching energy of the non-linear optical material in this work was 30 μJ/cm² at 337 nm (0.3 pJ/μm²).