T. T. Heikkila

Low-noise amplification and frequency conversion with a multiport microwave optomechanical device

  1. C. F. Ockeloen-Korppi,
  2. E. Damskägg,
  3. J.-M. Pirkkalainen,
  4. T. T. Heikkilä,
  5. F. Massel,
  6. and M. A. Sillanpää
High-gain amplifiers of electromagnetic signals operating near the quantum limit are crucial for quantum information systems and ultrasensitive quantum measurements. However, the existing
techniques have a limited gain-bandwidth product and only operate with weak input signals. Here we demonstrate a two-port optomechanical scheme for amplification and routing of microwave signals, a system that simultaneously performs high-gain amplification and frequency conversion in the quantum regime. Our amplifier, implemented in a two-cavity microwave optomechanical device, shows 41 dB of gain and has a high dynamic range, handling input signals up to 1013 photons per second, three orders of magnitude more than corresponding Josephson parametric amplifiers. We show that although the active medium, the mechanical resonator, is at a high temperature far from the quantum limit, only 4.6 quanta of noise is added to the input signal. Our method can be readily applied to a wide variety of optomechanical systems, including hybrid optical-microwave systems, creating a universal hub for signals at the quantum level.
arxiv pdf

Single-photon cavity optomechanics mediated by a quantum two-level system

  1. J.-M. Pirkkalainen,
  2. S. U. Cho,
  3. F. Massel,
  4. J. Tuorila,
  5. T. T. Heikkila,
  6. P. J. Hakonen,
  7. and M. A. Sillanpaa
Coupling electromagnetic waves in a cavity and mechanical vibrations via the radiation pressure of the photons is a promising platform for investigations of quantum mechanical properties
of motion of macroscopic bodies and thereby the limits of quantum mechanics [3,4]. A drawback is that the effect of one photon tends to be tiny, and hence one of the pressing challenges is to substantially increase the interaction strength towards the scale of the cavity damping rate. A novel scenario is to introduce into the setup a quantum two-level system (qubit), which, besides strengthening the coupling, allows for rich physics via strongly enhanced nonlinearities [5-8]. Addressing these issues, here we present a design of cavity optomechanics in the microwave frequency regime involving a Josephson junction qubit. We demonstrate boosting of the radiation pressure interaction energy by six orders of magnitude, allowing to approach the strong coupling regime, where a single quantum of vibrations shifts the cavity frequency by more than its linewidth. We observe nonlinear phenomena at single-photon energies, such as an enhanced damping due to the two-level system. This work opens up nonlinear cavity optomechanics as a plausible tool for the study of quantum properties of motion.
arxiv pdf