Three-dimensional phononic crystal with ultra-wide bandgap at megahertz frequencies

Phononic crystals have attracted wide attention in diverse scientific communities due to their ability efficiently reflect, focus, and guide acoustic elastic waves. Their use ultrasonic applications such as medical imaging, however, remains elusive since three-dimensional phononic with lattice constants the range of hundreds micrometers are required operate MHz ultrasound, smaller than what most additive manufacturing solutions can provide. This work presents a crystal cubic symmetry having an experimental ultra-wide complete bandgap extending from 0.6 7.5 MHz. Crystal specimens manufactured using two-photon lithography at microscale, constant 300 μm, characterized heterodyne interferometry.