A team of researchers from Abdullah University of Science and Technology (KAUST) demonstrated generating Bessel Beams using a custom-engineered optical fiber.
Image Credits: Optica Publishing Group
The team has demonstrated generating Bessel Beams using a custom-engineered optical fiber fabricated with two photon lithography. The photon lithography enables 3D printing of intricate optical structures to beam-shaping elements. The design has three segments that align and transform the Gaussian beam into an annular beam and then to Bessel beam effectively.
The Bessel beams posses self-healing and diffraction free propagation properties. They can also carry different orbital angular momentum (OAM). These beams, also known as Vortex beams have a characteristic ring-like shape with a dark central region.
Despite the properties, creating these beams require bulk optical elements like cone-shaped axions or spatial light modulators.
“Generating Bessel beams using traditional techniques involves space-consuming, expensive optical elements that require precise alignment,” said Innem Reddy, a Ph.D. student in the research group. “By opting for a fiber-based solution, we can obtain a compact Bessel beam generator that is pre-aligned and can deliver these beams even in remote and confined spaces, such as endoscopic applications.”
The team has already used TPL to customize fibers for polarization of beam splitters, optical tweezers, and microlens assemblies.
“Fabricating ever more sophisticated optical devices on the end of optical fibers to empower them to deliver complex functionalities is one of the main research directions of our group,” said researcher Carlo Liberale, a research associate in bioscience at KAUST.
The researchers suggest that the same approach can be applied to multimode fibers to expand the mode of conversion and possibilities. This new way of converting Gaussian beams into Bessel Beams is anticipated to create a positive impact on applications including optical and quantum communications. These are also expected to make impact in fiber-based sensors, spectroscopy, optical trapping and microscopy.
