Spintronics for long-distance telecommunications

In a collaborative effort spanning continents, a team of scientists that includes Professor Jian-Ping Wang has successfully modulated magnetic information using electrical pulses while converting it into a polarized light signal. Details of the work are described in the journal Nature in an article titled, “Controlling the helicity of light by electrical magnetization switching.” The spintronics-based discovery has the potential to revolutionize long-distance optical telecommunications. 

In spintronics, information is represented by the spin of electrons and the direction of their magnetization. However the removal of the electrons from the material results in the loss of the spin information. The research team has overcome this limitation by deploying light as a spin carrier, where the spin of electrons is transferred to photons. The phenomenon of spin-orbit interaction (which is, interestingly enough, also responsible for the loss of spin information when electrons are moved outside the material) makes it possible to transfer the spin information from electrons to photons. The circular polarization of light called helicity is instrumental in this bearing of information. The researchers have successfully demonstrated the use of electrical pulses to change the helicity of light thereby allowing for spin information of electrons to now be carried by photons. Filling in the missing link that allows for information transfer from electrons to photons is particularly significant for potential applications such as next generation information and communication technologies that are not only ultrafast but also highly energy efficient. 

Commenting on the research and his contribution, Distinguished McKnight Professor and Robert F. Hartmann chair Jian-Ping Wang says, “It is great to see spin-orbit-torque materials be among the  enablers to demonstrate this first ever spin-photon device. We are glad to be part of this large team to try out different spin-orbit-torque materials.”

Read the details of the study at Nature

The team comprised scientists from the following institutions: Institut Jean Lamour, Université de Lorraine, CNRS, UMR 7198, Nancy, France; Laboratoire Albert Fert, CNRS, Thales, Université Paris-Saclay, Palaiseau, France; Université de Toulouse, INSA-CNRS-UPS, LPCNO, Toulouse, France; Université Paris-Saclay, CNRS, Centre de Nanosciences et de Nanotechnologies, Palaiseau, France; Photonics and Terahertz Technology, Ruhr-Universität Bochum, Bochum, Germany; Key Laboratory of Semiconductor Materials Science, Institute of Semiconductors, Chinese Academy of Sciences, Beijing, China; College of Materials Science and Opto-Electronic Technology, University of Chinese Academy of Sciences, Beijing, China; Platform Photonics Research Center, National Institute of Advanced Industrial Science and Technology, Tsukuba, Japan; Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing, China; Chemistry and Nanoscience Center, National Renewable Energy Laboratory, Golden, CO, USA; Department of Physics, University at Buffalo, State University of New York, Buffalo, NY, USA, and Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, MN, USA.