Mechanical Kerr Nonlinearity of Wave Propagation in an On-Chip Nanoelectromechanical Waveguide

Abstract

Nonlinearity is the key to introducing novel concepts in various technologies utilizing traveling waves. In contrast to the field of optics, where highly functional devices have been developed using optical Kerr nonlinearity 1-3 , such a nonlinear effect in acoustic devices has yet to be fully exploited. Here, we show that most fundamental nonlinear phenomena of self-phase modulation (SPM), cross-phase modulation (XPM) and four-wave mixing (FWM) caused by the acoustic Kerr effect are quantitatively characterized using a newly developed platform consisting of a planar nanoelectromechanical waveguide (NEMW). Combining the cutting-edge technology of a high crystalline quality NEMW with a piezoelectric interdigital transducer (IDT), we efficiently excite an intense and long-lived traveling wave sufficiently to induce and characterize acoustic nonlinearity. The observed nonlinear phenomena are precisely described by the model using the nonlinear Schrödinger (NLS) equation, so that this architecture enables the nonlinear dynamics to be perfectly tailored. The flexible and integratable platform extends the ability to manipulate acoustic wave propagation on a chip, thus offering the potential to develop highly functional devices and study novel nonlinear acoustics.

Experimental Demonstration of Dual‐Band Nano‐Electromechanical Valley‐Hall Topological Metamaterials

“…[ 30 ] The calculated spectrum of γ 0 in Figure 4c confirms that perfect phase matching can lead to enhanced SHG efficiency (black dot in Figure 4c). Since nano‐electromechanical systems with large mechanical nonlinearities have been reported, [ 31 ] we believe that the experimental realizations of second‐harmonic generation [ 32 ] and parametric down‐conversion [ 33 ] are within reach by using our nano‐electromechanical QVH topological insulators.…”

Tunnelling of transverse acoustic waves on a silicon chip

“…Previously, processes used to fabricate membranebased phononic devices have relied either on deepbackside etching [17,18] or on the use of wavelengthscale holes in the membrane to enable front-side etching [19,20]. For backside etching processes, the need to etch through a several hundred micron-thick substrate has limited both precision and feature size of the phononic components, while in the case of front-side etching, the wavelength-scale hole pattern [10,21,22] directly affects the dispersion relations of the guided modes, and limits the ability to fabricate arbitrary waveguide shapes.…”

Observation of chiral edge states in gapped nanomechanical graphene

“…Various graphene-related phenomena that are challenging in solid-state physics have been experimentally demonstrated in these synthetic metamaterials, such as Zitterbewegung oscillation ( 16 ), Klein tunneling ( 17 ), unconventional bearded edge states ( 12 ), and solitons ( 18 ). Among these photonic and phononic metamaterials, nanomechanical system with electrical tunability ( 19 ) and strong nonlinearity ( 20 ) is one of the most promising platforms to explore graphene-related physics. On this platform, high-frequency phonons can be generated, waveguided, routed, and detected with high efficiency and high speed.…”