van den Hooven Thomas J, Planken Paul C M
Advanced Research Center for Nanolithography (ARCNL), Science Park 106, 1098 XG Amsterdam, The Netherlands.
Van der Waals-Zeeman Institute, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands.
Photoacoustics. 2023 Apr 29;31:100497. doi: 10.1016/j.pacs.2023.100497. eCollection 2023 Jun.
We report on surface-plasmon-polariton-enhanced (SPP-enhanced), strain-wave-induced reflection and diffraction changes on a Au-covered, segmented grating. The segmented grating has a 6020 nm period, and its lines are segmented into 7 periods of a 430 nm period grating, which allows the excitation of SPPs. This grating has three SPP resonances at different optical wavelengths, for the same incident angle. Pump-pulse-induced strain waves are probed by measuring reflection and diffraction of a tunable probe pulse in a wavelength range that includes all three SPP resonances. Surface Acoustic Waves (SAWs) and Longitudinal Waves (LWs) are identified. When probing close to SPP resonances, the reflection changes from SAWs and LWs are strongly enhanced by factors of 23 and 36, respectively, compared with reflection changes observed when probing at off-resonance wavelengths. The relative SAW- and LW-induced diffraction changes are larger by additional factors of up to 3.3 and 2.6, respectively, compared to the reflection changes.
我们报道了在金覆盖的分段光栅上表面等离子体激元极化子增强（SPP增强）、应变波诱导的反射和衍射变化。该分段光栅的周期为6020 nm，其线条被分割成7个周期为430 nm的光栅周期，这使得能够激发表面等离子体激元。对于相同的入射角，该光栅在不同的光波长处有三个表面等离子体激元共振。通过测量可调谐探测脉冲在包括所有三个表面等离子体激元共振的波长范围内的反射和衍射来探测泵浦脉冲诱导的应变波。识别出了表面声波（SAW）和纵波（LW）。当在接近表面等离子体激元共振处进行探测时，与在非共振波长处探测时观察到的反射变化相比，表面声波和纵波引起的反射变化分别强烈增强了23倍和36倍。与反射变化相比，表面声波和纵波引起的相对衍射变化分别额外增大了高达3.3倍和2.6倍。
