Transition from the ballistic to the snake regime of a femtosecond laser through a turbid medium via Monte Carlo simulation

Abstract

We study the transition from the ballistic to the snake regime of a femtosecond laser through a turbid medium via Monte Carlo simulation. The results show that the transition depth of the ballistic to the snake regime of a femtosecond laser through a turbid medium is close to the surface of the scattering volume. The transition process depends on the scattering coefficient of the turbid medium. Unlike the decay of the intensities of the ballistic photons governed by Beer–Lambert law, the intensities of the snake photons first increase with an increase of the thickness of the turbid medium and then decrease with a further increase of the thickness, for all scattering coefficients ranging from 10 to 20 cm−1. Further, we study the balance point of the intensity of the ballistic photons and the snake photons, which also depends on the scattering coefficient and the half-acceptance angle. The transmission depth corresponding to the transition balance point decreases with an increase of the scattering coefficient. In addition, for the transition balance point, the product of the transmission depth and scattering coefficient is approximately a constant (∼2) for a specific simulation configuration.

Computational ghost imaging through a dynamic scattering medium based on a convolutional neural network from simulation

“…According to the central limit theorem, if a noise is generated by the superposition of many mutually independent noise sources, this noise obeys the Gaussian distribution. In addition, we found that the effect of noise on ghost imaging mainly comes from the rise and fall characteristics rather than the average value according to equation (2). Therefore, we may try to add different intensities of Gaussian white noise to the LIS to simulate different conditions of actual experimental environment.…”

“…passing through the scattering medium will be highly scattered and diffused into a complex speckle pattern, which makes it difficult to establish the point-to-point relationship [1,2]. Many methods have been proposed to overcome or make use of scattering effects, such as adaptive optics [3], wavefront shaping [4], correlation imaging [1,5], multiphoton fluorescence imaging [6] and optical coherence tomography [7].…”