Comparison of laser-induced breakdown spectra of organic compounds with irradiation at 15 and 1064 μm

A comprehensive investigation of laser-induced breakdown spectroscopy (LIBS) at 1.500 microm of residues of six organic compounds (anthracene, caffeine, glucose, 1,3-dinitrobenzene, 2,4-dinitrophenol, and 2,4-dinitrotoluene) on aluminum substrates is presented and compared with LIBS at the Nd:YAG fundamental wavelength of 1.064 microm. The overall emission intensities were found to be smaller at 1.500 microm than at 1.064 microm, and the ratios of C(2) and CN molecular emissions to the H atomic emissions were observed to be less. Possible reasons for the observed differences in LIBS at 1.064 microm versus 1.500 microm are discussed.