| 摘要 |
PURPOSE:To provide a method for generating an ultrasonic wave on a solid sample using laser having relatively low output. CONSTITUTION:A laser light source 10 emits a laser beam 12 of frequency f1. The beam 12 is split by a beam splitter 14 into two beams 1, 2. One beam 2 is shifted by a frequency deltaf through a frequency shifter 16. These beam 1, 2 impinge on a microtarget region P on the surface 20a of a solid sample at incident angles of theta1, theta2, respectively. The beams 1, 2 are combined in the target region P and interfere each other. When the frequency difference between the first and second beams 1, 2, and the incident angles theta1, theta2 satisfy the following relationship; C.deltaf=V.f1.¦(sintheta1-sintheta2)¦, ultrasonic wave is generated on the surface 20a of solid sample (C represents the speed of light, and V represents the propagation phase speed of ultrasonic wave on the surface of solid sample). |
