Yang Fan, Gyger Flavien, Godet Adrien, Chrétien Jacques, Zhang Li, Pang Meng, Beugnot Jean-Charles, Thévenaz Luc
Ecole Polytechnique Fédérale de Lausanne (EPFL), Group for Fibre Optics, CH-1015, Lausanne, Switzerland.
European Molecular Biology Laboratory, Heidelberg, Germany.
Nat Commun. 2022 Mar 17;13(1):1432. doi: 10.1038/s41467-022-29051-8.
Brillouin scattering has been widely exploited for advanced photonics functionalities such as microwave photonics, signal processing, sensing, lasing, and more recently in micro- and nano-photonic waveguides. Most of the works have focused on the opto-acoustic interaction driven from the core region of micro- and nano-waveguides. Here we observe, for the first time, an efficient Brillouin scattering generated by an evanescent field nearby a single-pass sub-wavelength waveguide embedded in a pressurised gas cell, with a maximum gain coefficient of 18.90 ± 0.17 mW. This gain is 11 times larger than the highest Brillouin gain obtained in a hollow-core fibre and 79 times larger than in a standard single-mode fibre. The realisation of strong free-space Brillouin scattering from a waveguide benefits from the flexibility of confined light while providing a direct access to the opto-acoustic interaction, as required in free-space optoacoustics such as Brillouin spectroscopy and microscopy. Therefore, our work creates an important bridge between Brillouin scattering in waveguides, Brillouin spectroscopy and microscopy, and opens new avenues in light-sound interactions, optomechanics, sensing, lasing and imaging.
布里渊散射已被广泛应用于先进的光子学功能，如微波光子学、信号处理、传感、激光等，最近还应用于微纳光子波导。大多数研究工作都集中在微纳波导核心区域驱动的光声相互作用上。在此，我们首次观察到在嵌入加压气室的单程亚波长波导附近，由倏逝场产生的高效布里渊散射，其最大增益系数为18.90±0.17 mW。该增益比空心光纤中获得的最高布里渊增益大11倍，比标准单模光纤中的增益大79倍。从波导实现强自由空间布里渊散射，得益于受限光的灵活性，同时提供了对光声相互作用的直接访问，这是布里渊光谱和显微镜等自由空间光声所需的。因此，我们的工作在波导中的布里渊散射、布里渊光谱和显微镜之间架起了一座重要的桥梁，并为光声相互作用、光机械学、传感、激光和成像开辟了新途径。
