Heat focusing by phononic nanostructures
Masahiro NOMURA1, Roman ANUFRIEV1
Phonon engineering is expected to achieve a breakthrough in thermal management technology in solids. In macroscopic systems, thermal conduction is diffusive and difficult to control. However, in mesoscopic systems, the ballistic property of thermal phonons enables more advanced heat conduction control. In this article, we demonstrate a method to control the direction of heat flow using silicon membranes with arrays of holes. The arrays of holes form phonon fluxes oriented in the same direction. We also demonstrate “thermal lens” nanostructures, in which the emitted thermal phonons converge at the focal point. These demonstrations raise the idea of ray phononics because of some similarity to ray optics. Advanced technology in photonics may serve as a good model for phonon engineering.
- 1 Institute of Industrial Science, The University of Tokyo