Control of quantum interference between nonlinear optical absorption processes in semiconductors

We report the first experiments demonstrating Quantum Interference Control (QuIC) based on two nonlinear optical absorption processes in semiconductors. We use two optical beams of frequencies f and 3⁄2 f incident on AlGaAs, and measure the injection current due to the interference between 2- and 3-photon (2p-3p) absorption processes. We analyze the dependence of the QuIC current on the intensities, phases, and polarizations of the incident fields. One advantage of this scheme is that the bandwidth required is reduced similar to optical 2f-3f self-referencing [4]. Moreover, in contrast to the one-photon—two-photon QuIC scheme, where the absorption lengths of two fields mismatch due to the strong above-band gap single photon absorption of light at 2f, in 2p-3p QuIC, the absorption lengths of both f and 3⁄2 f fields are more than tens of microns because the photon energies of both light fields are below the band-gap energy. Single photon absorption is thus greatly suppressed, allowing the design of integrated devices using waveguides.