0000000000314195
AUTHOR
Tommi Hakala
Applications of light-matter interaction in nanosciences
In this thesis, light matter interaction in nanoscale has been studied from various aspects. The interaction between surface plasmon polaritons (SPPs) and optically active organic molecules (Rhodamine 6G, Sulforhodamine 101 and Coumarine 30) and semiconducting nanocrystals (quantum dots) is studied in the weak coupling regime. In particular, a photon-SPP-photon conversion with spatially separated inand outcoupling was demonstrated by using molecules. Also, a frequency downconversion for propagating SPPs was presented by utilization of vibrational relaxation of organic molecules. A strong coupling regime was reached for Rhodamine 6G (R6G) and SPP despite the broad absorption linewidth of R6G…
Absence of mutual polariton scatterings for strongly coupled surface plasmon polaritons and dye molecules with large Stokes shift
The understanding and control of the dynamics of hybrid modes consisting of strongly coupled surface plasmon polaritons and molecular excitations of dye molecules is of great timely interest, as it allows one to tailor interactions between optical signals as needed for active all-optical devices. Here we utilize dye molecules with an especially large Stokes shift to demonstrate the absence of mutual scatterings among the strongly coupled hybrid modes. We employ a quantum mechanical three-level model and show that the hybrid modes decay via dephasing and internal relaxation of the molecules to a fluorescing state of the dye, which can be used as a measure for the decay. Our results provide e…