Simulation of penetration depth of Bessel beams for multifocal optical coherence tomography

Abstract

Multifocal Bessel beam optical coherence tomography (MBOCT) combines the advantages of Bessel beam OCT and multifocal OCT to increase imaging depth. For MBOCT, the penetration depth of the Bessel beam in highly scattering biological tissue limits the final imaging depth. In this paper, we theoretically analyze the penetration depth of the Bessel beams with different parameters to explore which kind of Bessel beam is more suitable for MBOCT in a scattering medium. The finite-difference time-domain method is used to simulate the field distribution of Bessel beams in the medium. We find that the MBOCT for more focus based on a Bessel beam with a smaller Fresnel number N has higher penetration depth and light intensity when its lateral resolution is fixed. Moreover, the Bessel beam with N reversely closer to unity is more advantageous for penetrating the highly scattering medium for a certain imaging depth, and the Bessel beam has larger penetration depth when its lateral size is close to the size of the object to be imaged.

Noise insensitive volumetric fusion method for enhanced photoacoustic microscopy

“…For sample with intricate structure (such as cerebrovascular), accurately quantifying the variation of FWHM and SNR along depth direction is difficult. In addition, the depth of optical focus experiences a shift due to the variations in scattering and absorption of heterogeneous samples 37 . The focused boundary cannot be approximated as a single plane.…”

“…In addition, the depth of optical focus experiences a shift due to the variations in scattering and absorption of heterogeneous samples. 37 The focused boundary cannot be approximated as a single plane. Therefore, this approach is not applicable to turbid biological tissue and limited to transparent sample with weak absorption and scattering such as water.…”

Exploration for adequate non-diffractive beam generation in dense scattering media

“…Optical sensing methods have been widely developed for biomedical imaging 1 – 3 and environmental measurements 4 – 6 . As an example, optical coherence tomography (OCT) is a non-invasive ophthalmologic diagnostic technique that renders an in-vivo cross-sectional view of the dense scattering media such as biomedical tissues up to a depth of less than 2 mm 7 – 9 . On the other hand, for long-range sensing, lidar is widely used for measuring optical properties of atmospheric particles and molecules that have smaller concentrations than biomedical tissues 10 .…”

Imitation of optical coherence tomography images by wave Monte Carlo-based approach implemented with the Leontovich–Fock equation

“…23 Using the Maxwell equations for the OCT simulations is suitable for modeling complex (profiled) laser beams. [24][25][26][27][28][29] However, it is very time-consuming, even using parallel algorithms, [30][31][32] and requires allocation of massive computer resources that significantly limits the spatial area of interest.…”