Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
Opt Lett. 2011 Aug 1;36(15):2925-7. doi: 10.1364/OL.36.002925.
In a modification of a picosecond ultrasonic technique, a short acoustic pulse is launched into a liquid sample by a laser pulse absorbed in a semitransparent transducer film and is detected via coherent Brillouin scattering of a time-delayed probe pulse. With both excitation and probing performed from the transducer side, the arrangement is suitable for in vivo study of biological tissues. The signal is collected from a micrometer-thick layer next to the transducer and is not affected by the diffuse scattering of probe light deeper in the sample. The setup, utilizing a 33 nm thick single crystal SrRuO(3) transducer film, is tested on a full fat milk sample, with 11 GHz acoustic frequency recorded.
在一种皮秒超声技术的改进中，通过吸收在半透明换能器薄膜中的激光脉冲将短声脉冲发射到液体样品中，并通过延迟探测脉冲的相干布里渊散射进行检测。由于激发和探测都是从换能器一侧进行的，因此该装置适用于生物组织的体内研究。信号从靠近换能器的一微米厚的层中收集，并且不受样品深处探测光的漫散射的影响。该装置利用 33nm 厚的单晶 SrRuO3 换能器薄膜进行测试，在全脂牛奶样品上记录到 11GHz 的声频。
