3D structured Bessel beam polarization and its application to imprint chiral optical properties in silica

Abstract

Polarization plays a crucial role in light–matter interactions; hence its overall manipulation is an essential key to unlock the versatility of light manufacturing, especially in femtosecond laser direct writing. Existing polarization-shaping techniques, however, only focus on their manipulation in the transverse plane of light beams, i.e., two-dimensional control. In this paper, we propose a novel passive strategy that exploits a class of femtosecond laser written space varying birefringent elements to shape the polarization state along the optical path. As a demonstration, we generate a three-dimensional structured Bessel beam whose linear polarization state slowly evolves along the focus (typ. 90° within 60λ). Such a “helically polarized” Bessel beam allows imprinting “twisted nanogratings” in SiO2 glass which result in an extrinsic optical chirality at a micrometric scale and own a high optical rotation. Our work provides new perspectives for three-dimensional polarization manipulation and insights into applications in structured light, light–matter interaction, and chiral device fabrication.

Ultra-low-cost and high-fidelity NIR-II confocal laser scanning microscope with Bessel beam excitation and SiPM detection

“…In view of the high price of InGaAs detectors, it has been proposed to use low-cost silicon photomultiplier tube (SiPM) detectors instead, and the price of the detector module is only a few tenths of the InGaAs detectors while obtaining similar imaging results [19]. In microscopy, there have also been many studies that have reported improved lateral resolution by using a non-diffractive beam [32][33][34][35][36][37][38][39].…”

Single Shot Generation of High‐Aspect‐Ratio Nano‐Rods from Sapphire by Ultrafast First Order Bessel Beam

“…[10,11] Additionally, beams featuring polarization states that evolve during propagation have enabled the fabrication of chiral structures within the bulk of fused silica. [12] Optical vortices have also emerged as effective tools for manipulating laser-matter interaction. In Gaussian laser beams, the phase singularity is responsible for doughnut-shaped crosssections.…”

“…[ 10,11 ] Additionally, beams featuring polarization states that evolve during propagation have enabled the fabrication of chiral structures within the bulk of fused silica. [ 12 ]…”