Related Experiment Video
Updated: May 16, 2026

High Resolution Phonon-assisted Quasi-resonance Fluorescence Spectroscopy
Published on: June 28, 2016
Determining phonon mean free paths from observations of quasiballistic thermal transport
1Division of Engineering and Applied Science, California Institute of Technology, Pasadena, California 91125, USA. aminnich@caltech.edu
Abstract:
The mean free paths (MFPs) of thermal phonons are mostly unknown in many solids. Recent work indicates that MFPs may be measured using experimental observations of quasiballistic thermal transport, but the precise relationship between the measurements and the MFP distribution remains unclear. Here, we present a method that can accurately reconstruct the MFP distribution from quasiballistic thermal measurements without any assumptions regarding the phonon scattering mechanisms. Our result will enable a substantially improved understanding of thermal transport in many solids, particularly thermoelectrics.
Related Concept Videos
Mean free path and Mean free time
IR Spectroscopy: Hooke's Law Approximation of Molecular Vibration
According to Hooke's law, the vibrational frequency is directly proportional to the...
Theory of Metallic Conduction
In this theory, Newton's second law of motion is used to determine the acceleration of an electron in the presence of an applied electric field. Then, its velocity is expressed via this acceleration.
An electron moves through the crystal, containing positive ions,...
The de Broglie Wavelength
Behavior of Gas Molecules: Molecular Diffusion, Mean Free Path, and Effusion
Speed of Sound in Solids and Liquids

