Institute of Applied Physics of the Russian Academy of Sciences, 46 Uljanova St., 603950 Nizhny Novgorod, Russia.
Sensors (Basel). 2021 Sep 13;21(18):6142. doi: 10.3390/s21186142.
We propose a laser optoacoustic method for the complex characterization of crude oil pollution of the water surface by the thickness of the layer, the speed of sound, the coefficient of optical absorption, and the temperature dependence of the Grüneisen parameter. Using a 532 nm pulsed laser and a 1-100 MHz ultra-wideband ultrasonic antenna, we have demonstrated the capability of accurate (>95%) optoacoustic thickness measurements in the 5 to 500-micron range, covering 88% of slicks observed during 2010 oil spill in the Gulf of Mexico. In the thermal relaxation regime of optoacoustic measurements, the value of optical absorption coefficient (30 mm) agreed with the data of independent spectrophotometric measurements, while the sound speed (1430 m/s) agreed with the tabular data. When operating in a nonlinear regime, the effect of local deformation of the surface of the oil film induced by heating laser radiation was revealed. The dose-time parameters of laser radiation ensuring the transition from the thermal relaxation regime of optoacoustic generation to nonlinear one were experimentally investigated. The developed OA method has potential for quantitative characterization of not only the volume, but also the degree and even the type of oil pollution of the water surface.
我们提出了一种激光光声方法，用于通过层厚、声速、光吸收系数以及 Grüneisen 参数的温度依赖性来复杂地表征水面原油污染。我们使用 532nm 脉冲激光和 1-100MHz 超宽带超声天线，证明了在 5 至 500 微米范围内进行精确（>95%）光声厚度测量的能力，覆盖了 2010 年墨西哥湾溢油事件中观察到的 88%的浮油。在光声测量的热弛豫阶段，光学吸收系数（30mm）的值与独立分光光度测量数据一致，而声速（1430m/s）与表格数据一致。当在非线性状态下运行时，揭示了由激光辐射加热引起的油膜表面局部变形的影响。实验研究了确保光声产生从热弛豫状态过渡到非线性状态的激光辐射剂量-时间参数。所开发的 OA 方法具有定量表征水面不仅体积，而且还可以定量表征污染程度甚至污染类型的潜力。
