Berlin 2012 – scientific programme
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O: Fachverband Oberflächenphysik
O 85: Plasmonics and nanooptics V
O 85.7: Talk
Friday, March 30, 2012, 12:00–12:15, MA 005
Detecting low concentrations of pollutant chemicals in water by SERS:Combining optimised nanoparticle ensembles and SERDS — •R. Ossig1, Y.-H. Kwon2,3, H.D. Kronfeldt2, and F. Hubenthal1 — 1Institut für Physik and CINSaT, Universität Kassel, Germany — 2Technische Universität Berlin, Institut für Optik und Atomare Physik, Germany — 3Institute of Lasers, Academy of Sciences, Unjong District, Pyongyang, DPR Korea
We present recently performed surface enhanced Raman spectroscopy (SERS) measurements using the combination of optimised silver nanoparticle (NP) ensembles and shifted excitation Raman difference spectroscopy (SERDS) to perform trace analysis of pollutant chemicals in water. The silver NPs were prepared under ultrahigh vacuum conditions on quartz substrates. The microsystem diode laser used is capable to generate two slightly different emission wavelengths (Δλ≈ 0.5 nm) with a spectral width of ≈ 10 pm, which is ideal for SERDS. To tune the surface plasmon resonance frequency of the NP ensembles in the vicinity of the excitation wavelength of the used diode laser, the morphology of the NPs was varied to obtain the optimal values for the investigated molecule-excitation wavelength combination. In this contribution we demonstrate, that optimising the optical properties of the silver NPs is essential for the detection of low pollutant concentrations. While for plasmon resonances in the vicinity of the excitation wavelength a low limit of detection in the order of 2 µ m/l, is obtained, slightly off resonance NP ensembles yield a limit of detection that is at least 10 times higher.