Coherent coupling between radio frequency, optical, and acoustic waves in piezo-optomechanical circuits (1508.01486v1)

Abstract: The interaction of optical and mechanical modes in nanoscale optomechanical systems has been widely studied for applications ranging from sensing to quantum information science. Here, we develop a platform for cavity optomechanical circuits in which localized and interacting 1550 nm photons and 2.4 GHz phonons are combined with photonic and phononic waveguides. Working in GaAs facilitates manipulation of the localized mechanical mode either with a radio frequency field through the piezo-electric effect, or optically through the strong photoelastic effect. We use this to demonstrate a novel acoustic wave interference effect, analogous to coherent population trapping in atomic systems, in which the coherent mechanical motion induced by the electrical drive can be completely cancelled out by the optically-driven motion. The ability to manipulate cavity optomechanical systems with equal facility through either photonic or phononic channels enables new device and system architectures for signal transduction between the optical, electrical, and mechanical domains.

• The paper introduces a GaAs platform that integrates 1550 nm optical photons and 2.4 GHz mechanical phonons through piezo-optomechanical circuitry.
• It employs both RF and optical drives to achieve coherent manipulation and demonstrates an acoustic interference effect akin to coherent population trapping.
• High optomechanical coupling (g0/2π ≈ 1.1 MHz) verifies the system’s sensitivity and paves the way for advanced quantum transduction applications.

Coherent Coupling in Piezo-Optomechanical Circuits

The paper "Coherent coupling between radio frequency, optical, and acoustic waves in piezo-optomechanical circuits" presents a detailed investigation into the integration of radio frequency (RF), optical, and acoustic domains in a piezo-optomechanical circuit framework. This paper is focused on using gallium arsenide (GaAs) as a platform due to its conducive properties for the integration of highly localized optical and mechanical modes with phononic and photonic waveguides.

Key Contributions

The research primarily revolves around the development of a platform that seamlessly integrates 1550 nm optical photons and 2.4 GHz mechanical phonons, utilizing both photonic and phononic waveguides. The novelty of this work lies in the manipulation and control of the mechanical resonator through either optical or RF means, facilitated by GaAs's strong photoelastic and piezoelectric effects.

A noteworthy highlight of the paper is the demonstration of an intriguing acoustic wave interference effect akin to atomic coherent population trapping. In this case, the mechanical motion induced by the electrical (RF) drive can be entirely canceled out by the optically-driven motion, showcasing a distinguished instance of coherent interaction that can be precisely modulated.

Experimental Setup and Findings

The experimental setup involves a GaAs nanobeam optomechanical crystal cavity, where the localized mechanical mode can be driven either through RF fields using interdigitated transducers (IDTs) or optically via photoelastic coupling. The system showcases an optomechanical coupling rate $g_{0}/2\pi \approx 1.1$ MHz, a value significantly higher than other piezo-optomechanical architectures, which magnifies the system's sensitivity and control capabilities.

Several experiments were conducted to validate the capabilities of this system:

• Phononic Waveguide Coupling: The paper demonstrates electrical input via IDTs converted efficiently to a propagating surface acoustic wave, coherently coupled to the optomechanical cavities.
• Coherent Manipulation and Detection: Using optical techniques, the researchers achieve coherent detection of mechanical motion with intracavity photon populations as low as one, proving the capability for precise control and experimental verification of quantum-limited sensitivities.
• Acoustic Coherent Population Trapping: By exploiting the phase and amplitude tuning of the RF drive, conditions were established for coherent mechanical state preparation. The complete suppression of mechanical resonator linewidth in the transmission spectrum (an acoustic analog to coherent population trapping) further verified the experimental control over the integrated system.

Implications and Future Directions

The successful coupling across these diverse domains on a single GaAs platform opens numerous avenues for signal processing and quantum information applications. The implications span from enhanced transduction mechanisms, increased integration of optomechanical systems with electronic circuits, to potentially new architectures for quantum networks.

Future research directions could explore optimized IDTs and more efficient routing geometries to further improve bidirectional waveform transduction efficiency and SMBS as an alternate acoustic energy source. Additionally, integrating quantum emitters like InAs/GaAs quantum dots may lead to hybrid systems exhibiting novel quantum mechanical phenomena, holding potential for breakthroughs in quantum communication and computation.

In conclusion, this work offers a significant step forward in the integration of RF, optical, and mechanical waves within a unified framework, presenting potential advancements and wide applicability in both classical and quantum technologies. The richness of coherent interactions facilitated by this platform underscores its promise for the development of next-generation optomechanical circuits.