TY - JOUR A1 - Yuan, Huan A1 - Gornushkin, Igor B. A1 - Gojani, Ardian A1 - Wang, X. H. A1 - Rong, Ming Zhe T1 - Laser-induced plasma imaging for low-pressure detection JF - Optics Express N2 - A novel technique based on laser induced plasma imaging is proposed to measure residual pressure in sealed containers with transparent walls, e.g. high voltage vacuum interrupter in this paper. The images of plasma plumes induced on a copper target at pressure of ambient air between 10−2Pa and 105Pa were acquired at delay times of 200ns, 400ns, 600ns and 800ns. All the plasma images at specific pressures and delay times showed a good repeatability. It was found that ambient gas pressure significantly affects plasma shape, plasma integral intensities and expansion dynamics. A subsection characteristic method was proposed to extract pressure values from plasma images. The method employed three metrics for identification of high, intermediate and low pressures: the distance between the target and plume center, the integral intensity of the plume, and the lateral size of the plume, correspondingly. The accuracy of the method was estimated to be within 15% of nominal values in the entire pressure range between 10−2Pa and 105Pa. The pressure values can be easily extracted from plasma images in the whole pressure range, thus making laser induced plasma imaging a promising technique for gauge-free pressure detection. KW - Laser induced plasma KW - LIBS KW - Plasma modeling KW - Plasma diagnostics PY - 2018 DO - https://doi.org/10.1364/OE.26.015962 SN - 1094-4087 VL - 26 IS - 12 SP - 15962 EP - 15971 PB - Optical Society of America under the terms of the OSA Open Access Publishing Agreement AN - OPUS4-45219 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -