著者

Sugawara Y. Wright O. B. Matsuda O. Takigahira M. Tanaka Y. Tamura S. Gusev2 V. E.

出版者

American Physical Society

雑誌

PHYSICAL REVIEW LETTERS (ISSN:00319007)

巻号頁・発行日

vol.88, no.18, pp.185504, 2002-04-18

被引用文献数

106

---

We present a new method for imaging surface phonon focusing and dispersion at frequencies up to 1 GHz that makes use of ultrafast optical excitation and detection. Animations of coherent surface phonon wave packets emanating from a point source on isotropic and anisotropic solids are obtained with micron lateral resolution. We resolve rounded-square shaped wave fronts on the (100) plane of LiF and discover isolated pockets of pseudosurface wave propagation with exceptionally high group velocity in the (001) plane of TeO2. Surface phonon refraction and concentration in a minute gold pyramid is also revealed.

著者

Hurley D. H. Wright O. B. Matsuda O. Shinde S. L.

出版者

American Institute of Physics

雑誌

Journal of Applied Physics (ISSN:00218979)

巻号頁・発行日

vol.107, no.2, pp.023521, 2010-01-15

被引用文献数

23

---

We use ultrashort optical pulses to microscopically image carrier and thermal diffusion in two spatial dimensions in pristine and mechanically polished surfaces of crystalline silicon. By decomposing changes in reflectivity in the latter sample into a transient component that varies with delay time and a steady-state component that varies with pump chopping frequency, the influence of thermal diffusion is isolated from that of carrier diffusion and recombination. Additionally, studies using carrier injection density as a parameter are used to clearly identify the carrier recombination pathway.