Fig. 2.

Remote identification of chemically similar samples. (A) Spontaneous Raman spectra of all of the chemicals where random Raman lasing has been observed. (B) Stimulated Raman spectra of similar chemicals taken at a distance of 400 m using a single laser pulse, illustrating that minute changes in the molecular makeup can be distinguished via SRS even with a relatively low resolution Ocean Optics USB2000 spectrometer with a spectral resolution of only 40 cm⁻¹. (C) The detected intensity from BaSO₄ as a function of distance from the sample the adjusted data are corrected for both mirror reflections and clipping losses. The error bars represent the SD of the 50 shot data set taken at each distance. (D) Distribution of the peak value of the stimulated Raman spectra fit using Gaussian statistics, illustrating that nearly identical chemicals are still distinguishable.