Remote sensing oil in water with an all-fiber underwater single-photon Raman lidar

Abstract

The detection of oil in water is of great importance for maintaining subsurface infrastructures such as oil pipelines. As a potential technology for oceanic application, an oceanic lidar has proved its advantages for remote sensing of optical properties and subsea materials. However, current oceanic lidar systems are highly power-consuming and bulky, making them difficult to deploy underwater to monitor oil in water. To address this issue, we have developed a compact single-photon Raman lidar by using a single-photon detector with high quantum efficiency and low dark noise. Due to the single-photon sensitivity, the detection of the relatively weak Raman backscattered signal from underwater oil was realized with a laser with a pulse energy of 1 µJ and a telescope with a diameter of 22.4 mm. An experimental demonstration was conducted to obtain the distance-resolved Raman backscatter of underwater oil of different thicknesses up to a distance of 12 m. The results indicate the single-photon Raman lidar’s potential for inspecting underwater oil pipelines.

GPU-Accelerated Monte Carlo Simulation for a Single-Photon Underwater Lidar

“…By improving the detection sensitivity to the single-photon level, single-photon lidar can achieve long-range and highprecision parameter detection while being compact and low power [6]. As a result, this system has been widely applied in atmospheric remote sensing [13][14][15], underwater target imaging [9], ship-mounted lidar [16], and, more recently, underwater lidar systems [6,17]. However, despite the development of single-photon underwater lidar systems, there is a lack of simulation techniques for accurately simulating their backscattered signals.…”

Underwater Single-Photon Lidar Equipped with High-Sampling-Rate Multi-Channel Data Acquisition System

“…Fortunately, the advent of single-photon detection technology has promoted the underwater deployment of lidar [13,14]. This technology enables lidar systems to achieve long detection ranges and high temporal-spatial resolution using only a low-pulse-energy laser and a small-aperture telescope, thereby realizing a compact, lightweight, and highly integrated design that facilitates deployment on underwater platforms, such as AUVs.…”

A perspective on single‐photon LiDAR systems

“…LiDAR 9 is more commonly used for general atmospheric observations, while Raman LiDAR 23 is employed when detailed knowledge of the atmospheric constituents is required. Single-photon LiDAR [24][25][26]27 takes LiDAR technology a step further. Single-photon LiDAR, also known as single-photon avalanche diode (SPAD) LiDAR or photoncounting LiDAR, simply uses single-photon detectors [28][29][30] to measure the time of flight of individual photons.…”

“…Single-photon detectors may be coupled not only with basic LiDAR but also with Raman LiDAR to enable the recognition of very weak Raman-scattered light, allowing for the measurement of trace gases and aerosols in the atmosphere, 26 or, recently, even oil leakages in the ocean, 27 with high precision. Importantly, single-photon LiDAR does not use a single-photon source to generate individual photons.…”

“…26 In the ocean, single-photon LiDAR can remotely distinguish various substances, identifying, for example, oil spills. 27 In a field application such as LiDAR, Raman LiDAR, or any other scattering-type application, a large number of photons are required to extract information associated with the scattering process, given the ambient noise associated with the process. The issue is that the greater the sensitivity of the detector, the more prone it will become to background noise, including the noise of the electronics required to build the detector.…”