Faserphotonik

We present results from the development of plasmonic chips for surface enhanced Raman spectroscopy (SERS). Our technological approach is based on the patterning of a resist film (PMMA) on a quartz substrate by electron beam lithography. The samples consist of periodic arrays of square shaped dots with lateral sizes around 300 nm, a period of 400 nm, and a height of 120 nm. This patterned surface is covered with a 10 nm Al2O3 film and a 40 nm Ag film. The electromagnetic field distribution as a function of the wavelength and incidence angle was simulated. The results show that field enhancements in the order of 10 can be achieved at 488 nm excitation wavelength. The SERS effect of the samples was investigated experimentally using crystal violet as a model analyte substance. The enhancement shows a good reproducibility and the values are consistent with the simulations.