Until now, it was thought impossible to distinguish the enantiomers of a chiral molecule using helical beams of light, thanks to a group of researchers from Wattawa.

For nearly 20 years, researchers believed it was impossible to distinguish the enantiomers of a chiral molecule using helical beams of light. Enantiomers are mirror images of a molecule that cannot be superimposed like our left and right hands and appear identical by simply changing its orientation. Also, molecules with symmetrical properties, such as achiral molecules, are not expected to be independent of light spirality.

Yet that’s what a group of researchers from the University of Ottawa did.

Professor Ravi Bhardwaj and Ph.D. led by a team. In collaboration with students Ashish Jain and Jean-Luc Begin, Professors Thomas Brabeck, Ebrahim Karimi of the Nexus Institute of Quantum Technology in Ottawa, and Paul Corkum, Head of the Canadian Department of Attosecond Photonics, have developed a new chiroptic technique to distinguish between the two. -overlapping mirror images of a chiral molecule. Its effectiveness can even be scaled and controlled using linearly polarized spiral light beams.

“Our understanding of the interaction of light and matter is mainly based on the propagation of uniformly polarized light and the predominance of dipole-active transitions between different quantum states of matter,” Jean-Luc Begin said. “High-order multi-domain effects are often overlooked. Our findings show their importance.”

Its main findings include:

• Increased chiral sensitivity can be observed directly using linearly polarized spiral light beams without any intermediaries.
• Differential absorption of left- and right-handed asymmetrical helical light can be observed even in achiral molecules that can be scaled and precisely controlled.
• Light absorption due to helicity results from the interaction of electric dipole and electric quadrupole moments and can be tuned by changing the laser polarization.

Ashish Jain added, “Detection of sensitized enantiomers is important in the pharmaceutical industry to eliminate the unwanted side effects of drugs.” “Furthermore, the proven control of spiral light-light-matter interactions potentially opens up new possibilities in spectroscopy, light-controlled molecular machines, optical switching, and ultrafast detection of magnetic materials.”