This work aims to implement 3D microstructures that generate light with orbital
angular momentum towards applications in Biophotonics.
Over the past few decades, 3D printing has established itself as the most versatile
technology with effortless adaptability. Parallel to this, the concept of miniaturiza tion has seen tremendous growth irrespective of the field and has become an estab lished trend motivated by the need for compact, portable and multi-function devices.
Therefore, when these two concepts get together, i.e., 3D printing of miniaturized
objects, it could lead to an exciting path with endless opportunities. When it comes
to optics, miniaturized 3D printing offers the potential to create compact optical
micro-systems and exhibits a way to manufacture freeform µ-optics. In particular,
two-photon lithography (TPL) is a cutting edge 3D printing technology that has re cently demonstrated groundbreaking solutions for optics as it offers high resolution
with a great degree of flexibility. With a TPL 3D printer, it is possible to fabricate
complex µ-optical elements and employ them for compelling applications.
In recent years, light with orbital angular momentum (OAM), or ”twisted” light,
has captured the interests of several researchers due to its inspiring applications. Tra ditionally, to generate OAM beams, one would require bulk, table-top optics, restrict ing their applications to over-the-table setup. An alternative approach of OAM beam
generation is through µ-structures over the fiber, as they can open up new opportu nities, especially in Bioscience, and facilitate in-vivo operations. In particular, this
probe-like setup can be used for processes such as optical trapping, high-resolution
microscopy, etc. Hence, I propose the development of a novel approach with un precedented capabilities for generating OAM beams right from single-mode optical
fibers, by transforming its Gaussian-like output beam by using complex 3D printed
microstructures. In this document, I will showcase designs and results on generating
Bessel beams (both zeroth- and high-order) and high-NA converging beams (with
and without OAM) for optical trapping from the fiber. Remarkably, I achieved the
first-ever fiber-based high-order Bessel beam generation and the first-ever fiber optical
tweezers with OAM.
|Date of Award||Nov 2021|
|Original language||English (US)|
- Biological, Environmental Science and Engineering
|Supervisor||Carlo Liberale (Supervisor)|
- 3D printing
- Orbital angular momentum
- Bessel beams
- fiber optical tweezers
- miniaturized optical systems