Fiber-integrated microcavities for efficient generation of coherent acoustic phonons
Fiber-integrated microcavities for efficient generation of coherent acoustic phonons
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DOI：
10.1063/5.0026959
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发表时间：
2020-11-02
影响因子：
4
通讯作者：
Lanzillotti-Kimura, N. D.
中科院分区：
文献类型：
--
作者：
Ortiz, O.;Pastier, F.;Lanzillotti-Kimura, N. D.
相干声子产生的光学泵浦探测实验，使平面异质结构，等离子体共振器，微柱和纳米线在纳米尺度上的声学特性的研究。将泵浦和探测聚焦在样品的同一点上是泵浦-探测实验的关键部分。这在小物体的情况下尤其重要。该技术的实际实施的主要实际挑战是时空重叠的稳定性、聚焦的再现性和光学模式匹配条件。在这项工作中，我们解决了这三个挑战的情况下，平面和微柱optophononic腔。我们将所研究的样品集成到单模光纤中，从而提高了对聚焦光学器件的需求，以激发和检测相干声学声子。在我们的样品中实现的至少66%的反射率对比度使我们能够在至少一整天内观察到稳定的相干声子信号，并且在1 μ W的极低激发功率下观察到信号。单片样品结构是可运输的，并且可以提供进行可再现的即插即用实验的手段。
Coherent phonon generation by optical pump-probe experiments has enabled the study of acoustic properties at the nanoscale in planar heterostructures, plasmonic resonators, micropillars, and nanowires. Focalizing both the pump and the probe on the same spot of the sample is a critical part of pump-probe experiments. This is particularly relevant in the case of small objects. The main practical challenges for the actual implementation of this technique are stability of the spatiotemporal overlap, reproducibility of the focalization, and optical mode matching conditions. In this work, we solve these three challenges for the case of planar and micropillar optophononic cavities. We integrate the studied samples to single mode fibers lifting the need for focusing optics to excite and detect coherent acoustic phonons. The resulting reflectivity contrast of at least 66% achieved in our samples allows us to observe stable coherent phonon signals over at least a full day and signals at an extremely low excitation power of 1 mu W. The monolithic sample structure is transportable and could provide a means to perform reproducible plug-and-play experiments.