Simultaneous microscopic imaging of elastic and thermal anisotropy

Abstract

Simultaneous imaging of elastic and thermal properties of anisotropic materials with micron (lateral) and nanometer (depth) resolution is presented. This approach employs an ultrafast laser for the generation and detection of thermal and acoustic waves. Demonstrations involving the visualization of thermal waves and surface acoustic waves are presented for single crystal quartz and fused silica substrates sputter coated with chromium films. These images dramatically reveal and contrast the symmetry of thermal and elastic properties and compare favorably with theoretical prediction. This hybrid approach shows great promise to investigate fundamental properties of materials and interfaces on both a low-frequency (elastic wave) and a high-frequency (phonon diffusion) scale.