Development Of Standoff Laser-Induced Thermal (Infrared) Emission (LITE) System For Chemical and Biological Materials

Laser-induced breakdown spectroscopy (LIBS) has shown great promise for applications in chemical, biological and explosive (CBE) sensing [1-12]. Nearly all previous LIBS experiments were limited to measurements in the UV-VIS and NIR. However, molecules exhibit spectroscopic signatures in the MIR to FIR wavelength region from vibrational and rotational transitions. Therefore, an extension of LIBS to the IR region promises to provide information which can augment results from conventional UV-VIS LIBS measurements. Recently, we have demonstrated the first infrared LIBS emission signatures in the 3-5 um spectral region [13-16]. By adding the feature of laser energy control it can operate both as LIBS and Laser Induced Thermal Emission (LITE) technique/system. We propose a detailed study of IR LITE/LIBS in 1-12 um range for potential applications in CBE sensing. We will systematically irradiate CBE species (and related materials) with a laser at progressive energies and parameter settings to yield evaporation/desorption/vaporization or ablation, and capture the IR spectra of emitted photons. Particular attention will be noted for point (short range) and standoff dual use utility. We will develop a breadboard system and outline a roadmap for a field portable instrument. We will also develop a signature library from selected biological and chemical solid-state materials.