Search results for "phononic crystals"
showing 3 items of 3 documents
Experimental Observation of a Large Low-Frequency Band Gap in a Polymer Waveguide
2018
The quest for large and low-frequency band gaps is one of the principal objectives pursued in a number of engineering applications, ranging from noise absorption to vibration control, and to seismic wave abatement. For this purpose, a plethora of complex architectures (including multiphase materials) and multiphysics approaches have been proposed in the past, often involving difficulties in their practical realization. To address the issue of proposing a material design that enables large band gaps using a simple configuration, in this study we propose an easy-to-manufacture design able to open large, low-frequency complete Lamb band gaps exploiting a suitable arrangement of masses and stif…
Fabrication of 3-D phononic crystals for thermal transport management
2016
Thermal transport is an important physical phenomenon, and it has recently become even more relevant for the reduction of energy losses and the increase of efficiency in novel devices based on thermoelectricity [1]. Significant reduction of thermal conduction was recently achieved by coherent modification of phonon modes [2], with the help of periodic phononic crystal structures. However, currently the experimental studies have only been performed for two-dimensional (2-D) nanostructures. Theoretically, the magnitude of control of thermal transport should be even stronger in three-dimensional (3-D) phononic crystal structures. For that reason, the question arises how to fabricate the desire…
Minimizing coherent thermal conductance by controlling the periodicity of two-dimensional phononic crystals
2019
Periodic hole array phononic crystals (PnC) can strongly modify the phonon dispersion relations, and have been shown to influence thermal conductance coherently, especially at low temperatures where scattering is suppressed. One very important parameter influencing this effect is the period of the structure. Here, we measured the sub-Kelvin thermal conductance of nanofabricated PnCs with identical hole filling factors, but three different periodicities, 4, 8, and 16 $\mu$m, using superconducting tunnel junction thermometry. We found that all the measured samples can suppress thermal conductance by an order of magnitude, and have a lower thermal conductance than the previously measured small…