Portable Shifted Excitation Raman Difference Spectroscopy for Agri- Photonics: From On-Site Precision Agriculture to Smart Farming

Portable shifted excitation Raman difference spectroscopy (SERDS) using two excitation wavelengths around 785 nm is applied for selected applications in the field of agri-photonics. In the presence of daylight and laser-induced fluorescence, SERDS effectively separates Raman signals of green apple leaves and soil substances with more than 10-fold improved signal-to-background-noise ratios. Major ingredients of bovine milk are clearly detected and identified. A quantitative determination of the fat content in milk is performed and shows a limit-of-detection of 0.1 g / 100 mL. These results show a great potential of portable SERDS for real-world applications, e.g., for precision agriculture and food monitoring.