[18a-WL2_201-1~10] 3.11 Nanoscale optical science and near-field optics

9:00 AM - 9:15 AM JST(12:00 AM - 12:15 AM UTC)Presentation by Applicant for JSAP Young Scientists Presentation Award

[18a-WL2_201-1] Molecular Nonlinear Responses in Mid-Infrared Resonators and Vibrationally Selective Excitation in Sub-Nanometer Confinement

〇(PC)Nobuaki Oyamada¹, Zhiyuan Xie¹, Christophe Galland¹ (1.EPFL)

Keywords:

Mid-infrared plasmon cavity,Non-linear optical responce,Thermal plasmonics

We demonstrate vibrationally selective excitation of a molecular monolayer driven by plasmon-enhanced infrared light. Sum-frequency generation (SFG) from a self-assembled monolayer of 4-nitrothiophenol was measured using a dual plasmonic resonator combined with a narrow-linewidth (<0.5 cm^-1) quantum cascade infrared laser. The SFG intensity shows pronounced modulations that are highly sensitive to both IR and Raman activity, indicating selective excitation of specific vibrational modes under enhanced SFG conditions. Raman analysis based on the Bose-Einstein distribution reveals that modes with strong induced dipole moments exhibit population excitation corresponding to a vibrational temperature increase of nearly 100 K.