Single-Mode Phononic Wire

Abstract

Photons and electrons transmit information to form complex systems and networks. Phonons on the other hand, the quanta of mechanical motion, are often considered only as carriers of thermal energy. Nonetheless, their flow can also be molded in fabricated nanoscale circuits. We design and experimentally demonstrate wires for phonons by patterning the surface of a silicon chip. Our device eliminates all but one channel of phonon conduction, allowing coherent phonon transport over millimeter length scales. We characterize the phononic wire optically, by coupling it strongly to an optomechanical transducer. The phononic wire enables new ways to manipulate information and energy on a chip. In particular, our result is an important step towards realizing on-chip phonon networks, in which quantum information is transmitted between nodes via phonons.

Lithium niobate piezo-optomechanical crystals

“…Electrical contacts between on-chip electrodes and aluminum wires are made with ultrasonic wire-bonding. Tapered optical mode converters are patterned on the LN layer with efficiency η ∼ 50% for coupling the OMCs to a lensed fiber [9]. Fig.…”

“…Optomechanical crystals (OMC) provide a powerful platform for engineering interactions between photons and phonons. Colocalizing optical and mechanical modes allows light to control and readout mechanical motion, leading to a large variety of quantum optomechanical experiments [1-5] and enabling routing and transduction of classical and quantum signals between microwave-frequency phonons and optical photons [6][7][8][9][10]. Silicon optomechanical crystals have strong coupling rates but lack intrinsic piezoelectricity [11].…”

Coupling a Superconducting Quantum Circuit to a Phononic Crystal Defect Cavity

“…In our scheme, only one mechanical mode, the localized mode, plays a role in the coupling. This removes any loss associated with inefficient mode conversion and scattering into spurious acoustic modes, e.g., arising from the multiple polarizations guided by the nanobeam [33]. Since there is only a single acoustic resonance present in the device at the frequency of interest, we are able to achieve efficient and tunable coupling that is robust to fabrication imperfections.…”

Polarization mode hybridization and conversion in phononic wire waveguides

“…It is anticipated that the strength of these interactions can be greatly enhanced by using phononic strip waveguides of subwavelength cross-section or phononic wires, to confine phonon fields 11,12 . Such high-confinement phononic circuits could perform functions that complement electronic and photonic circuits, at operation frequencies matching that of microwave and wavelengths matching that of optical signals [13][14][15][16][17] .Similar to optical waveguides which support orthogonal polarization transverse-electrical (TE) and transverse-magnetic (TM) modes, phononic waveguides support two types of phonon modes: the vertically polarized (with dominant out-of-plane motion) Rayleighlike mode and the horizontally polarized (with dominant in-plane motion) Love-like mode. While the Rayleighlike mode is piezoelectrically active and has been extensively studied in literature and more commonly utilized in today's RF signal processing devices 2,18 , the Love-like mode is particularly interesting for building high quality factor (Q) acoustic resonators and for sensing applications due to their relative immunity to air and fluid damping 4,19-21 .…”

“…It is anticipated that the strength of these interactions can be greatly enhanced by using phononic strip waveguides of subwavelength cross-section or phononic wires, to confine phonon fields 11,12 . Such high-confinement phononic circuits could perform functions that complement electronic and photonic circuits, at operation frequencies matching that of microwave and wavelengths matching that of optical signals [13][14][15][16][17] .…”