UC San Diego researchers develop optical switching for data storage
- Optical switching could soon make data storage more than 1,000 times faster by using engineered light instead of traditional magnetic fields.
- In standard hard drives, tiny magnetic regions represent the 1s and 0s of digital information.
- To bypass this physical barrier, the UC San Diego team redesigned the light itself rather than inventing a new material.
Optical switching could soon make data storage more than 1,000 times faster by using engineered light instead of traditional magnetic fields. Researchers at the University of California San Diego published these findings in Nature Communications, detailing an approach that shrinks laser beams to unprecedented scales to control magnetic memory density.
Overcoming Thickness Constraints in Magnetic Layers
In standard hard drives, tiny magnetic regions represent the 1s and 0s of digital information. Switching these states usually requires an external magnetic field, which consumes significant energy and limits writing speeds. Previous attempts at optical switching were restricted to ultra-thin magnetic stacks containing no more than three layers.
According to study senior author Abdoulaye Ndao, a professor in the Department of Electrical and Computer Engineering at the UC San Diego Jacobs School of Engineering, prior experiments revealed that expanding the material beyond three layers halted optical switching. Consequently, a strict limitation was placed on the overall thickness of the magnetic material, which in turn restricted its capacity for long-term memory retention.
Engineering Light at the Microscale
To bypass this physical barrier, the UC San Diego team redesigned the light itself rather than inventing a new material. By shaping and shrinking an ultrafast laser beam to dimensions tens of orders of magnitude smaller than previous methods, the researchers successfully induced optical switching in a thicker magnetic material composed of nine alternating layers of platinum and cobalt.
We’ve optically engineered the light to change the physics that’s happening in the material at the micro- and nanoscale, said study first author Muhammad Waleed Khalid, an electrical and computer engineering Ph.D. student in Ndao’s research group.
The method concentrates energy onto a tiny area using multiple ultrafast pulses. Initial pulses heat a microscopic zone to reverse its magnetic orientation, while subsequent laser pulses expand the switched region until stability is reached.
Khalid explained that utilizing a customized laser enabled them to precisely tailor the beam’s dimensions and geometry. This flexibility opened avenues to investigate deeper physical principles unattainable through standard beam lasers.
Pathways to Commercialization
The collaboration combined expertise from optics and thin-film magnetic materials, uniting Ndao’s research group with Eric Fullerton, an expert in thin-film magnetic materials, professor of electrical and computer engineering, and chemical and nano engineering at UC San Diego. Despite proving that optical switching works in thicker films without relying on specific light polarization, practical hurdles remain.
The current setup relies on a specialized ultrafast laser that cannot yet be easily integrated into standard computer chips. Moving forward, the research team is investigating alternative magnetic materials compatible with more accessible lasers and aiming to shrink the laser beam down to a few hundred nanometers.