Unexpected spin alkali atoms unlock MRI possibilities
It has long been known that atoms can have one of several values of electron spin that are defined by quantum theory. Research conducted at the Laboratory for Optical Physics and Engineering (LOPE) by Professor James Gary Eden, alumnus J.D. Hewitt (MSEE '10, PhD '13), and post-doctoral researcher Andrey Mironov has demonstrated an optical process by which the electron spin of the alkali metals, such as cesium and rubidium, can be specified. Eden is the Intel Alumni Endowed Chair in Electrical and Computer Engineering and is affiliated with the Coordinated Science Lab (CSL) and Micro and Nano Technology Lab (MNTL).
By laser illumination of a mixture of alkali metal vapor and rare gas atoms, it is now possible to produce alkali atoms with certain degrees of spin, but not others. This process was unexpected, but appears to be of considerable value for biomedical imaging techniques, such as Magnetic Resonance Imaging (MRI).
These findings are described in a paper published in Physical Review Letters entitled “Spin Polarization of Rb and Cs np2P3/2 (n=5, 6) Atoms by Circularly Polarized Photoexcitation of a Transient Diatomic Molecule.”
Spin polarized alkali atoms interact with and can transfer polarization to noble gases such as helium or xenon. When the spin is transferred, it is given to the patient to inhale. This process is typically used for imaging the lungs, but can be used on any part of the human body that a gas can enter.
“We believe that there are several interesting applications of these excited polarized alkali atoms and are pursuing research to learn more about them. It could be used in quantum memory; we hope to check this soon”, said Mironov.
In addition to this, Mironov and Eden are also currently conducting research to prove that this method can be used to increase the emission efficiency of lasers or to realize new types of atomic clocks.
The LOPE was established in the early 1950s by the last student of Marie Curie, Professor Ladislas Goldstein. Eden is the third director. His group often pursues an eclectic mix of research topics that frequently combine physics, physical chemistry, optics and photonics.
Mironov describes their approach towards research as very unique in that it is driven by the “outlook of a hobbyist.” He believes that it is this temper that often inspires their success in research.