Sugawara Y, Wright O B, Matsuda O, Takigahira M, Tanaka Y, Tamura S, Gusev V E
Department of Applied Physics, Faculty of Engineering, Hokkaido University, Sapporo 060-8628, Japan.
Phys Rev Lett. 2002 May 6;88(18):185504. doi: 10.1103/PhysRevLett.88.185504. Epub 2002 Apr 18.
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 TeO(2). Surface phonon refraction and concentration in a minute gold pyramid is also revealed.
我们提出了一种用于在高达1GHz频率下对表面声子聚焦和色散进行成像的新方法，该方法利用超快光学激发和检测。以微米级横向分辨率获得了从各向同性和各向异性固体上的点源发出的相干表面声子波包的动画。我们解析了LiF（100）平面上的圆角方形波前，并在TeO₂的（001）平面中发现了具有异常高群速度的伪表面波传播的孤立区域。还揭示了微小金金字塔中的表面声子折射和聚集现象。
