Coherent Generation of Photo-Thermo-Acoustic Wave from Graphene Sheets.

Yichao Tian, He Tian, Y L Wu, L L Zhu, L Q Tao, W Zhang, Y Shu, D Xie, Y Yang, Z Y Wei, X H Lu, Tian-Ling Ren, Chih-Kang Shih, Jimin Zhao

Index: Sci. Rep. 5 , 10582, (2015)

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Abstract

Many remarkable properties of graphene are derived from its large energy window for Dirac-like electronic states and have been explored for applications in electronics and photonics. In addition, strong electron-phonon interaction in graphene has led to efficient photo-thermo energy conversions, which has been harnessed for energy applications. By combining the wavelength independent absorption property and the efficient photo-thermo energy conversion, here we report a new type of applications in sound wave generation underlined by a photo-thermo-acoustic energy conversion mechanism. Most significantly, by utilizing ultrafast optical pulses, we demonstrate the ability to control the phase of sound waves generated by the photo-thermal-acoustic process. Our finding paves the way for new types of applications for graphene, such as remote non-contact speakers, optical-switching acoustic devices, etc.