Regensburg 2016 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 18: Plasmonics and Nanooptics I: Microscopy
HL 18.7: Talk
Monday, March 7, 2016, 16:45–17:00, S054
Polarization sensitive scanning near field optical microscope on polymer thin films — •Jens Brauer1, Jinxin Zhan1, Petra Groß1, Christoph Lienau1, Daniel Trefz2, and Sabine Ludwigs2 — 1Carl von Ossietzky Universität, Oldenburg, Germany — 2Institut für Polymerchemie, Stuttgart, Germany
Currently there is a high need to investigate the relationship between structure and functionality of novel, polymer-based organic solar cell materials. Specfically information about local fluctuations of their optical properties, largely affecting the charge carrier mobility is needed [1]. For this, an optical imaging method is required with a spatial resolution in the order of the domain size, typically a few nanometers, or even below.
Here we present a technique to use near field optical microscopy to fulfill these requirements. We use a Titanium:Sapphire laser focused through the sample onto a sharp gold tip and collect the scattered near-field signal from the tip in a backscattering geometry. By applying a modulation to the tip with tens of kilohertz and using a lock-in amplifier after detection to demodulate the signal at the n-th harmonic we can significantly increase the signal to noise ratio. Changing the direction of the linear laser polarization enables us to determine the molecular orientation with a resolution of about 10 nm. In this talk we present a first demonstration by applying the technique to ordered and unordered thin film polymer samples.
[1] Brinkmann, M. et al.; ACS Nano 6, pp 10319-10326 (2012)