Researchers at NIST have developed a new method for polarizing helium-3 gas using spin-exchange optical pumping, achieving a record 88% polarization level. The technique involves using “chirped” volume Bragg gratings to spectrally narrow high-power diode array lasers, which improves the efficiency of the optical pumping process.
The increased polarization is expected to enhance the performance of neutron spin filters, which are used in various applications including medical imaging and nuclear physics research. However, the exact mechanism behind the improved polarization is still not fully understood, and further research is needed to push the limits of the spin-exchange optical pumping method and achieve 100% polarization.
The NIST team is continuing their efforts to study the relaxation processes, accurate polarization measurements, and optical pumping techniques to better understand and optimize the spin-exchange optical pumping method for various applications.
Keywords: Polarization, Neutron spin filters, Spin-exchange optical pumping, Alkali-metal atoms
