Plasmonic enhancement of photo-acoustic inducedreflection changes

Publication date
DOI http://dx.doi.org/10.1364/ao.432659
Reference G. de Haan, V. Verrina, A.J.L. Adam, H. Zhang and P.C.M. Planken, Plasmonic enhancement of photo-acoustic inducedreflection changes, Appl.Opt. 60, 24: 7304-7313 (2021)
Group Light-Matter Interaction

In this paper, we report on surface-plasmon-resonance enhancement of the time-dependent reflection changes caused by laser-induced acoustic waves. We measure an enhancement of the reflection changes induced by several acoustical modes, such as longitudinal, quasi-normal, and surface acoustic waves, by a factor of 10–20. We show that the reflection changes induced by the longitudinal and quasi-normal modes are enhanced in the wings of the surface plasmon polariton resonance. The surface acoustic wave-induced reflection changes are enhanced on the peak of this resonance. We attribute the enhanced reflection changes to the longitudinal wave and the quasi-normal mode to a shift in the surface plasmon polariton resonance via acoustically induced electron density changes and via grating geometry changes.