Near-field probing of strong light-matter coupling in single IR antennae

Quantum well intersubband polaritons are traditionally studied in large scale systems, over many wavelengths in size. In this presentation, we demonstrate that it is possible to detect and investigate intersubband polaritons in a single subwavelength nanoantenna in the IR frequency range. We observe polariton formation using a scattering-type near-field microscope and nano-FTIR spectroscopy. We will discuss near-field spectroscopic signatures of plasmonic antennae with and without coupling to the intersubband transition in quantum wells located underneath the antenna. Evanescent field amplitude spectra recorded on the antenna surface show a mode anti-crossing behavior in the strong coupling case. We also observe a corresponding strong-coupling signature in the phase of the detected field. We anticipate that this near-field approach will enable explorations of strong and ultrastrong light-matter coupling in the single nanoantenna regime, including investigations of the elusive effect of ISB polariton condensation

Apertureless optical near-field imaging of localized modes of silicon nanodisks

We measure near-field distributions of Mie-type optical modes of silicon nanodisks using apertureless near-field optical microscopy. Excellent agreement with numerical predictions is obtained, further enabling multipole analysis of the observed modes

Ir spectroscopic characterization of the thermally induced isomerization in carbon disulfide dimer anions

Contains fulltext : 99090.pdf (publisher's version ) (Closed access