Physicists use optical vortex beams to control atomic ionization

A team of researchers at the University of Ottawa has made great strides in understanding the ionization of atoms and molecules, a fundamental process in physics that affects a variety of fields such as x-ray generation and plasma physics.

A study entitled “Orbital Angle Momentum Control of Strong Field Ionization in Atoms and Molecules” is published in Nature Communications.

Think about atoms, that is, all the building blocks around us. Sometimes they lose electrons and become charged particles (that is ionization). It happens in lightning, plasma television, and even in aurora. Until now, scientists thought that this process could only be controlled in a limited way.

Leaded by Rabi Bardwaj, a full professor in the Faculty of Physics in Utawa, PhD student Jean-Luc is working with Professors Ebrahim Karimi, Paul Corkum and Thomas Brabec to introduce innovative methods of controlling ionization using specially structured light beams.

Ionization is important in powerful field physics and attosecond science, where it explains how electrons escape from atomic bonds. Traditionally, it was understood that this process cannot be operated beyond certain limits. However, this new study challenges that concept.

“We have demonstrated that by using a light beam carrying angular momentum, we can precisely control how electrons are ejected from an atom,” explains Professor Bardwaji. “This discovery opens up new possibilities for enhancing technology in areas such as imaging and particle acceleration.”

This study was conducted for more than two years at Utawa’s advanced research complex. The team found that the dominant hand and characteristics of the optical vortex beam have a significant effect on the ionization rate. By adjusting the position of the “null intensity region” within the beam, they achieved selective ionization and introduced a new concept called photodichroism.

This work is based on the fundamental theory of the field and could revolutionize the way scientists approach ionization. This is not just a physics textbook. This could lead to better medical imaging, faster computers, and ways to learn more efficient materials. Controlling individual particles is particularly promising for quantum computing, where it is important.

Professor Bhardwaj said, “While changing the way we think about how we emit electrons has been challenging, our research proves that using advanced laser technology leads to new discoveries that impact both science and technology.”