Light transmission characteristic analyses of a laser screen in clear water based on the Monte Carlo method

In order to optimize the design of underwater light screens, the transmission process of the light beam in water is analyzed with the Monte Carlo method. The trajectories and power attenuation of emitted photons, propagating in different types of water from the light source towards the receiver with different initial light powers and transmission distances, are simulated and calculated. The output power can then be obtained to calculate the transmission ratio quantitatively. According to the simulated data, by using the curving fitting method, the exact expression of transmission ratio is derived, which is in the same form as the Beer-Lambert-Bouguer law. Meanwhile, experiments are conducted in a light screen with a vertical line beam laser in clear water to verify the simulations. The experimental results are in agreement with the simulated results, and the differences between them are within ±0.04. The presented results give insight into the design of underwater laser screens.