<B>Abstract:</B>

Parametric amplifiers exploit a nonlinearity of a circuit to transfer power from a strong pump tone to a weak signal. If the nonlinearity is purely reactive, the amplifier need not add noise beyond what is required by quantum mechanical uncertainty. Indeed, microwave frequency Josephson parametric amplifiers have demonstrated sensitivity approaching the quantum limit, but are narrow band due to the need for resonant circuits. Wideband amplifiers are desirable as they allow for the processing of either rapidly varying signals or multiple narrowband signals encoded in a single communication channel. Here we show that highly efficient microwave frequency four-photon mixing can be achieved in a traveling wave device using the nonlinearity of the kinetic inductance. We demonstrate parametric gain in an unoptimized version of our device extending over 2 GHz on either side of an 11.56 GHz pump tone, confirming the principle of operation.

The large dynamic range of the device is consistent with many applications for which transistor amplifiers are currently used. Its simple, distributed layout suggests that this concept may extend to amplifiers optimized for use throughout the millimeter wave band.

Light refreshments will be served after the seminar.