報告題目：Picosecond laserultrasonics : principle and application
報 告 人：Prof.Osamu Matsuda, Division of Applied Physics, Faculty of Engineering,Hokkaido University, Japan
Absorption of subpicosecond laser pulses in a medium may generatepicosecond acoustic pulses therein. The propagation of generatedacoustic pulses can be monitored with delayed laser pulses through thetransient optical reflectance change. The technique is calledpicosecond laser ultrasonics and is used for the evaluation ofmultilayer structures in nano- or micrometer thicknesses as well asfor the evaluation of physical properties of materials. In this talk,some of our works to extend the applicability of laserpicosecond acoustics are introduced; the generation and detection ofsub-THz acoustic waves in semiconductor quantum wells, and thegeneration and detection of shear acoustic waves, and thesimultaneous evaluation of sound velocity and refractive index of atransparent medium with a grating structure.
Osamu Matsuda received M. Sci. (1988) andDr. Sci.(1991) degrees inPhysics both from Faculty ofScience, Osaka University, Japan. He wasa research associate in Osaka University from 1991 to 1998. Then hehas been an associate professor in Faculty of Engineering, Hokkaidouniversity, Japan since 1998 until now. He has been working on theoptical properties of amorphous semiconductors, picosecond laserultrasonics, time-resolved optical imaging of acoustic waves, phononiccrystals, phononicsmetamaterials, and ultrasonic force microscopes.He has published a series of influential articles in authoritative journals such as Physical Review Lettersand Physical Review B.Osamu Matsuda's research in this field is authoritative and leading.