2020, Müller, André, Sumpf, Bernd

Compact nonlinear frequency conversion of a Y-branch distributed Bragg reflector (DBR) diode laser for alternating dual-wavelength laser emission at 532 nm is presented for the very first time. The developed light source, realized on a 5 × 25 mm2 micro-optical bench, is based on single-pass second harmonic generation of a 1064 nm Y-branch DBR diode laser in a periodically poled lithium niobate waveguide crystal with superimposed poling periods. Phase-matching is obtained by intrinsic wavelength stabilization of the laser and wavelength tuning by implemented heater elements above the DBR gratings. Obtained optical output powers of 5.6 mW at 532.45 nm and 6.7 mW at 531.85 nm are limited by central lobe power contents of 52% available for waveguide coupling. With a spectral performance showing narrowband emission with spectral widths of 0.01 nm (0.4 cm−1) limited by the spectral resolution of the spectrum analyzer and a spectral spacing of 0.6 nm (20 cm−1), the developed light source is suitable for applications such as Raman spectroscopy and shifted excitation Raman difference spectroscopy (SERDS). Separate electrical contacts of the Y-branch diode laser enable alternating operation at both wavelengths.

2019, Hesse, Ronald, Bundesmann, Carsten, Denecke, Reinhard

The improvement of the software UNIFIT 2020 from an analysis processing software for photoelectron spectroscopy (XPS) only to a powerful tool for XPS, Auger electron spectroscopy (AES), X-ray absorption spectroscopy (XAS), and Raman spectroscopy requires new additional programme routines. Particularly, the implementation of the analysis of Raman spectra needs a well-working automatic spike correction. The application of the modified discrete Laplace operator method allows for a perfect localization and correction of the spikes and finally a successful peak fit of the spectra. The theoretical basis is described. Test spectra allow for the evaluation of the presented method. A comparison of the original and spike-corrected real measurements demonstrates the high quality of the method used.