Microstructured Phononic Crystal Isolates from Ultrasonic Mechanical Vibrations

Abstract

The functioning of many micro-electromechanical devices with parts oscillating at high frequencies require isolation from external vibration. Phononic crystals, presenting band-gaps in the dispersion spectrum, i.e., interval of frequency in which propagating waves are attenuated, can provide an effective solution for vibration shielding at the microscale. In the present work, we design—through numerical simulations—a 3D phononic crystal with a micrometric unit cell able to work as vibration isolator for a micro system. We exploit the direct writing technique based on two-photon polymerization to realize three prototypes of different dimensions. Experimental measurements performed with a Michelson interferometer demonstrate the effectiveness of the proposal.

Phonon Engineering of Micro‐ and Nanophononic Crystals and Acoustic Metamaterials: A Review

“…Although such an effort can be easily transitioned to the microscale, as has been done in photonic crystals and MMs, [ 124–127 ] curiously, it has been only sporadically implemented in PnCs and AMMs at the same length scale. One of the closest examples is realized by Zega et al [ 128 ] who designed 3D PnCs at the microscale with a large bandgap with a gap to the midgap ratio of 134.87% and confirmed its existence with experiment, as shown in Figure . Nonetheless, this study was not a direct result of topology optimization; instead, the configuration was inspired by the topologically optimized 3D PnCs composed of a single material endowed with an ultrawide complete bandgap investigated by D’Alessandro et al [ 99 ] Hence, the design of PnCs and AMMs at the microscale will benefit tremendously from the various proposed topology optimization methods to achieve desired properties, which have been demonstrated to be helpful at the macroscale PnCs and AMMs, as well as microscale photonic crystals.…”

“…Despite the importance and ubiquity of nonlinearity in microscale PnCs and AMMs, a deep understanding of their nonlinear behaviors and applications is still lacking. In this section, some common nonlinearities that have been intensively [128] Copyright 2022, The Authors, published by MDPI. investigated in periodic materials are summarized.…”

“…c) Nondimensional transmission diagram computed on a 2 Â 2 Â 3 PnC. a-d) Reproduced under the terms of the CC-BY Creative Commons Attribution 4.0 International license (https:// creativecommons.org/licenses/by/4.0) [128]. Copyright 2022, The Authors, published by MDPI.…”

Homogenization and metamaterials: an effective alliance

“…The fabrication of metamaterials, often periodic, with complex microstructure, is nowadays possible thanks to significant technological advances in micro-lithography, three-dimensional printing and multi-photon polymerization (Zega et al (2022), Cang et al (2022)).…”