Non-Diffracting Light Wave: Fundamentals and Biomedical Applications

Abstract

The light propagation in the medium normally experiences diffraction, dispersion, and scattering. Studying the light propagation is a century-old problem as the photons may attenuate and wander. We start from the fundamental concepts of the non-diffracting beams, and examples of the non-diffracting beams include but are not limited to the Bessel beam, Airy beam, and Mathieu beam. Then, we discuss the biomedical applications of the non-diffracting beams, focusing on linear and nonlinear imaging, e.g., light-sheet fluorescence microscopy and two-photon fluorescence microscopy. The non-diffracting photons may provide scattering resilient imaging and fast speed in the volumetric two-photon fluorescence microscopy. The non-diffracting Bessel beam and the Airy beam have been successfully used in volumetric imaging applications with faster speed since a single 2D scan provides information in the whole volume that adopted 3D scan in traditional scanning microscopy. This is a significant advancement in imaging applications with sparse sample structures, especially in neuron imaging. Moreover, the fine axial resolution is enabled by the self-accelerating Airy beams combined with deep learning algorithms. These additional features to the existing microscopy directly realize a great advantage over the field, especially for recording the ultrafast neuronal activities, including the calcium voltage signal recording. Nonetheless, with the illumination of dual Bessel beams at non-identical orders, the transverse resolution can also be improved by the concept of image subtraction, which would provide clearer images in neuronal imaging.

Self-healing of structured light: a review

“…2(a)), Mathieu modes [45] (Fig. 2(b)), parabolic modes [46], and other general nondiffracting structured modes [47][48][49].…”

Calculation of a diffraction-free beam with the given transverse intensity distribution using an iterative algorithm

“…The increased interest in the development and formation of new types of diffraction-free beams is associated with their huge success in various applications, including microscopy, laser structuring, information coding, and metrology [26][27][28][29][30][31][32][33] . Diffraction-free beams play a special role in holographic optical tweezers for controlled laser manipulation of an ensemble of microparticles.…”

Terahertz structured light: nonparaxial Airy imaging using silicon diffractive optics

“…Structured electromagnetic fields have been shown to be viable in a variety of applications such as communication, metrology, and light-matter interactions 1,2 . Most advances are due to the rapid development of socalled nondiffracting electromagnetic beams 3 which nowadays are applicable for a broad selection of wavelengths extending from visible 4 to terahertz (THz) ranges 5 . Such popularity is caused by intriguing properties like diffraction and dispersion resistance 6 , selfhealing 7,8 , self-acceleration [9][10][11] , etc.…”