Development of IR Laser Induced Breakdown Spectroscopy employing a Mercury Cadmium Telluride Array Detector
Technical Report,01 Feb 2015,30 Sep 2016
Hampton University Hampton United States
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New instrumentation including an eye-safe laser and a mercury cadmium telluride MCT array detector-spectrometer system were purchased and tested for infrared laser-induced breakdown spectroscopy IR-LIBS experiments. Conventional LIBS is limited to atomic type transitions in the UV-VIS-NIR region 0.2-1 m. It is well known, however, that molecules exhibit spectroscopic signatures in the long-wavelength IR region. In this project, the IR LIBS 2-12 m facility at HU was extended to include an eye-safe laser operating at 1.5 m for comparative studies using a conventional 1.064 m Nd YAG laser. In addition, a MCT array detector with 128 elements was incorporated into the IR LIBS setup for atomic and molecular IR LIBS of solid-state samples relevant for CBE sensing applications. In comparison to the single element MCT detector, the new MCT array system allowed the rapid detection of IR LIBS emission signatures from several potassium compounds incl. KCl, KClO3, KClO4. Time-resolved IR LIBS studies, however, revealed that the longer-lived molecular emissions exhibited rather weak signal strength. Comparative LWIR LIBS studies of several solid-state samples were performed using a NdYAG laser at 1.064 m and the new eye-safe laser operating at 1.574 m. Under the same experimental conditions, the IR LIBS emissions using an eye-safe laser exhibited nearly identical LIBS signatures but with slightly reduced intensity compared to 1.064 m laser excitation.
- Test Facilities, Equipment and Methods