Undergraduate research reveals how twisting light could uncover molecular handedness
By: Communications
A final-year undergraduate research project at the University of East Anglia (UEA) has resulted in a first-author journal publication, uncovering new ways that the twist of light can influence nonlinear optical processes.
The study, published in the Journal of the Optical Society of America B, is led by recent MPhys graduate Szymon Krukowski, alongside his project supervisor, Dr Kayn Forbes, from UEA's School of Chemistry, Pharmacy and Pharmacology.
Light is usually described in terms of its colour, intensity and polarisation. However, it can also be structured into optical vortices: beams whose wavefronts twist as they travel, carrying orbital angular momentum.
Krukowski and Forbes investigated whether this additional property could control a nonlinear optical process known as third-harmonic generation, in which three photons interact with a material to produce light at three times the original frequency.
Their theoretical research addresses a longstanding restriction in nonlinear optics. In liquids containing randomly oriented molecules, third-harmonic generation driven by circularly polarised plane waves is forbidden within the conventional electric-dipole description. By accounting for additional electric-field components that emerge when a structured beam is tightly focused, the researchers demonstrated theoretically how this process becomes possible.
Their calculations also predict that the generated light can acquire a distinctive vortex structure, demonstrating how the spin and orbital angular momentum of light can interact during nonlinear optical processes.
The researchers subsequently considered chiral molecules, which exist in left- and right-handed forms, much like our hands. Using molecular quantum electrodynamics, they predicted a new phenomenon termed third-harmonic vortex dichroism. This effect allows the nonlinear optical response to be controlled by reversing the direction in which the incoming light twists. Crucially, the response also depends on molecular handedness, potentially opening new opportunities for chiral spectroscopy and molecular identification.
The publication represents an outstanding achievement for Krukowski, whose research originated in his final-year undergraduate project at UEA. Working under the supervision of Forbes, he developed his project into original research of sufficient scientific significance to secure a first-author publication in an international, peer-reviewed journal.
This achievement highlights the exceptional research opportunities available to undergraduate students at UEA. Rather than simply studying established scientific concepts, students have the opportunity to work alongside active researchers, investigate unanswered scientific questions and contribute directly to advances in their fields.
Krukowski's success demonstrates how undergraduate research at UEA can extend well beyond the classroom, producing internationally recognised scientific publications and providing students with invaluable experience at the forefront of modern research.
Although experimental validation remains a future objective, the research establishes new theoretical possibilities for controlling nonlinear optical processes and investigating molecular chirality using the twist of light.
'Orbital angular momentum control of third-harmonic generation and vortex dichroism in isotropic media' can be found in the Journal of the Optical Society of America B.
Related Articles
Scientists discover surprising new way to control light
UEA scientists have uncovered a hidden property of light that allows it to twist, spin and behave differently - without mirrors, materials or special lenses.
Read more
Anti-aging drug Rapamycin extends lifespan as effectively as eating less
The anti-aging drug Rapamycin has the same life-extending effect as eating less, according to new research from UEA.
Read more
UEA produces England's most decorated early career pharmacists
UEA’s first graduates from the NQP-IP programme are the only pharmacists in England to gain triple recognition of the PGDip, Independent Prescriber, and RPS Credential, through an integrated programme redefining early career pharmacist training.
Read more