Ultrafast acoustics in the middle UV range: coherent phonons at higher frequencies and in smaller objects.
We show that the propagation of coherent acoustic phonons generated by femtosecond optical excitation can be clearly resolved using a probe laser in the middle UV (MUV) range. The MUV probe is easily produced from a high-repetition-rate femtosecond laser and a homemade frequency tripler. We present various experimental results that demonstrate efficient and high frequency detection of acoustic phonons. Thus, we show that the MUV range offers a unique way to reach higher frequencies and probe smaller objects in ultrafast acoustics.
Institut d’Électronique, de Microélectronique et de Nanotechnologie, Unité Mixte de Recherche CNRS 8250,Avenue Poincaré BP 69, F-59652 Villeneuve d’Ascq Cedex, France.
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Ayrinhac
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Devos
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Le Louarn
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Mante
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Emery