Laser remote sensing of underwater objects

Wojtanowski, J.; Mierczyk, Zygmunt; Zygmunt, Marek

doi:10.1117/12.799779

Cited by 5 publications

(5 citation statements)

References 3 publications

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“…The value of z e for our NCF was calculated using the following parameters: excitation wavelength of 785 nm, Raman frequency ranging from 0 cm −1 to 2020 cm −1 (corresponding to 785 nm–933 nm for the 785 nm wavelength excitation). The absorption coefficients for the low-concentration mixed solutions of ethanol and water were approximately determined on the basis of that of pure water, which are 2.5 dB/m at the excitation wavelength (785 nm) and 4.5 dB/m at the Raman frequency (933 nm) [ 38 , 39 ]. The confinement loss of the NCF was analyzed utilizing the COMSOL Multiphysics software, and the 0.0077 dB/m and 0.027 dB/m at 785 nm and 933 nm were numerically calculated for the NCF fully filled with the mixed solutions.…”

Section: Numerical Analysismentioning

confidence: 99%

Microfluidic Raman Sensing Using a Single Ring Negative Curvature Hollow Core Fiber

Wang

Gao

et al. 2021

Biosensors

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A compact microfluidic Raman detection system based on a single-ring negative-curvature hollow-core fiber is presented. The system can be used for in-line qualitative and quantitative analysis of biochemicals. Both efficient light coupling and continuous liquid injection into the hollow-core fiber were achieved by creating a small gap between a solid-core fiber and the hollow-core fiber, which were fixed within a low-cost ceramic ferrule. A coupling efficiency of over 50% from free-space excitation laser to the hollow core fiber was obtained through a 350 μm-long solid-core fiber. For proof-of-concept demonstration of bioprocessing monitoring, a series of ethanol and glucose aqueous solutions at different concentrations were used. The limit of detection achieved for the ethanol solutions with our system was ~0.04 vol.% (0.32 g/L). Such an all-fiber microfluidic device is robust, provides Raman measurements with high repeatability and reusability, and is particularly suitable for the in-line monitoring of bioprocesses.

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Section: Numerical Analysismentioning

confidence: 99%

Microfluidic Raman Sensing Using a Single Ring Negative Curvature Hollow Core Fiber

Wang

Gao

et al. 2021

Biosensors

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“…Most substances are large enough to be Mie scatterers (Wojtanowski et al, 2008) and, thus, scatter quite uniformly across the visible spectrum (Piech and Walker, 1971). However, the amount of scattering and spectral absorption of mineral particles is still very different from phytoplankton (Fig.…”

Section: Spectral Response Of Water With (In)organic Constituentsmentioning

confidence: 99%

“…Besides being the frequency-doubled version of the conventional 1064 nm laser (Wojtanowski et al, 2008), the information above clearly indicates that this laser wavelength has a very good chance to maximally penetrate different water bodies, hit the bottom of the water body, and return an echo to the airborne receiver. .…”

Section: The Green Laser Solutionmentioning

confidence: 99%

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Airborne laser bathymetry – detecting and recording submerged archaeological sites from the air

Doneus

Doneus²,

Briese

et al. 2013

Journal of Archaeological Science

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A new generation of airborne bathymetric laser scanners utilises short green laser pulses for high resolution hydrographic surveying in very shallow waters. The paper investigates its use for the documentation of submerged archaeological structures, introducing the concept of airborne laser bathymetry and focussing on a number of challenges this novel technology still has to face. Using this method, an archaeological pilot study on the northern Adriatic coast of Croatia has revealed sunken structures of a Roman villa. The results demonstrate the potential of this novel technique to map submerged archaeological structures over large areas in high detail in 3D, for the first time providing the possibility for systematic, large-scale archaeological investigation of this environment. The resulting maps will provide unique means for underwater heritage management.

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“…High-speed photography in water is complicated and expensive due to the light compensation and protection needed. Large-area real-time detection and motion parameter acquisition are critical for short-range defense and a characteristic analysis of high-speed projectile motion [8][9][10][11][12][13][14]. To overcome the above limits in short-range detection, an underwater light barrier with laser transmitting and receiving integration is proposed.…”

Section: Introductionmentioning

confidence: 99%

Velocity Measurement of a Highspeed Underwater Projectile With Laser Barriers

2021

IEEE Access

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To improve the precision of velocity measurements for high-speed underwater projectiles and meet the requirements for device terminal alarms, a method for identifying and measuring high-speed underwater projectiles with a large-area laser barrier was proposed. The absorption of laser transmission underwater and the relationship between scattering and suspended particles were simulated and analyzed. An optical system consisting of a waterproof modulated laser transceiver probe, multifiber transmission and a retroreflector was designed to decrease the large optical energy dissipation. The laser beam was expanded to form a triangular barrier with a Powell prism. The fiber array surrounding the prism receives the reflected laser light from the retroreflector. The other end of the optical fiber is coupled to a PIN-PD detector through a narrowband filter. The output electric signal is then processed by an amplifier, demodulator and low-pass filter. The shortcomings of traditional split-type and multielement optical structures in water were effectively overcome by this compact integrated probe structure, and the effective area was expanded to 2 m×2 m. The velocity of high-speed underwater steel balls and lead blocks, the simulated projectiles, was acquired accurately to verify the feasibility of velocity measurement for highspeed underwater projectiles with laser barriers.

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Laser remote sensing of underwater objects

Cited by 5 publications

References 3 publications

Microfluidic Raman Sensing Using a Single Ring Negative Curvature Hollow Core Fiber

Microfluidic Raman Sensing Using a Single Ring Negative Curvature Hollow Core Fiber

Airborne laser bathymetry – detecting and recording submerged archaeological sites from the air

Velocity Measurement of a Highspeed Underwater Projectile With Laser Barriers

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