A portable shifted excitation Raman difference spectroscopy system: device and field demonstration. (14th June 2016)

• Record Type: Journal Article
• Authors: Maiwald, Martin; Müller, André; Sumpf, Bernd; Tränkle, Günther
• Is Part Of: Journal of Raman spectroscopy. Volume 47:Number 10(2016)
• Page Start: 1180
• Page End: 1184
• Publication Date: 2016-06-14
• Subjects: shifted excitation Raman difference spectroscopy -- SERDS -- 785 nm -- diode laser -- handheld probe; Raman spectroscopy -- Periodicals; 535.846
• DOI: 10.1002/jrs.4953
• Languages: English
• ISSNs: 0377-0486

Abstract

Abstract : In this paper, we present a portable shifted excitation Raman difference spectroscopy (SERDS) system applied in outdoor experiments. A dual‐wavelength diode laser emitting at 785 nm is used as excitation light source. The diode laser provides two individually controllable excitation lines at 785 nm with a spectral distance of about 10 cm −1 for SERDS. This monolithic light source is implemented into a compact handheld Raman probe. Both components were developed and fabricated in‐house. SERDS measurements are performed in an apple orchard, and apples and green apple leafs are used as test samples. For each excitation wavelength, a single Raman spectrum is measured with 50 mW at the sample. Strong background interference from ambient daylight and laser‐induced fluorescence obscure the Raman signals. SERDS efficiently separates the wanted Raman signals from the disturbing background signals. For the Raman spectroscopic investigations of green leafs, one accumulation with an exposure time of 0.2 s was used for each excitation wavelength to avoid detector saturation. An 11‐fold improvement of the signal‐to‐background noise is achieved using SERDS. The results demonstrate the suitability of the portable SERDS system for rapid outdoor Raman investigations. Copyright © 2016 John Wiley & Sons, Ltd. Abstract : A portable shifted excitation Raman difference spectroscopy (SERDS) system is applied in outdoor experiments. An in‐house developed Raman probe with an implemented dual‐wavelength diode laser at 785 nm is used for the investigations. Raman spectra of, for example, green leafs with 0.2 s integration time are presented. SERDS efficiently separates the Raman signals from fluorescence and daylight contributions with an 11‐fold improvement of the signal‐to‐background noise. The results demonstrate the suitability of the portable SERDS system for rapid outdoor Raman investigations.