A QUANTIZED-CURRENT STANDARD BASED ON COHERENT PI-PULSE EXCITATION OFA QUANTUM-DOT

A quantized-current standard tied to the frequency standard (I = ef) i s proposed based on coherent optical pi-pulse excitation of a quantum dot. Fluctuations in the current are calculated by averaging the quant um dot density matrix over the basis states of an incident coherent-st ate pi-pulse. The effects of a finite population lifetime (T1) and dip ole lifetime (T2) via an appropriate Markoff approximation are include d. We show that a quantized-photocurrent accuracy, (ef - [I])/ef, of 1 part in 10(4) at a current of I = 1.6 pA (f = 10 MHz) is possible in a semiconductor quantum dot system operating at 2 K. Such a device may be useful for the generation of photon number states in quantum optic s, i.e. the realization of a photon current standard.