Fig. 1. Raman and fluorescence spectral ranges (excitation light wavelength is 266 nm)

Fig. 2. Baseline correction. (a) Morphological algorithm; (b) polynomial fitting algorithm

Fig. 3. Baseline correction based on morphology and polynomial joint

Fig. 4. Comparison of correction effects for different baselines using different methods. (a) Sine function; (b) Gaussian function;(c) Sigmoid function; (d) logarithmic function

Fig. 5. Influence of parameter setting on baseline correction effect

Fig. 6. Sample preparation and experimental device. (a) Sample preparation; (b) UV Raman spectroscopy setup

Fig. 7. Original spectra of potassium nitrate samples on different substrates

Fig. 8. Results of baseline correction of potassium nitrate powder on different substrates obtained by Mor+poly and airPLS algorithms. (a) Paper; (b) transparent acrylic sheet; (c) blue acrylic sheet; (d) metal aluminum