Holograms Can Improve Electronic Devices

Multiplicative use of sensors is generating huge amounts of data calling for ever-increasing storage requirements. Researchers are looking for newer memory devices capable of storing substantially more than the capability of current devices. Now a team of researchers has found new holographic memory devices that can offer unprecedented data storage capabilities in electronic devices.

Devices such as the holographic memory typically use optical beams to store data. The newer devices use spin waves instead. Spin waves are a collective oscillation of spins in magnetic materials and using them is advantageous in two ways. Spin wave devices are compatible with the conventional electronic devices – no need to convert electrons to light. Additionally, these operate at much shorter wavelengths compared to optical devices, which allows for manufacturing smaller electronic devices with greater storage capacity.

Researchers from the Russian Academy of Science and the Riverside Bourns College of Engineering, University of California, demonstrated the experimental feasibility of applying holographic techniques. They created a device, a magnonic holographic memory, by applying holographic techniques they developed in optics to magnetic structures. They were able to combine the advantages of wave-based information transfer with the magnetic data storage capabilities.

According to Alexander Khitun, the lead researcher and a research professor at UC riverside, the results of the experiment has thrown open a new field of research. This could profoundly affect the development of new memory and logic devices. The researchers have submitted a paper describing their findings to the journal Applied Physics Letters for publication.

Most people know of holography as being associated with driver’s license or paper currency where images are made from light. This technique is based on the wave nature of light. It uses interfering waves such as those between the object beam and the coherent background. However, this is only a small application of holography.

In 1940s, electron microscopes were the first to use holograms. After about a decade, optical holographic images became popular with the advent of lasers. Since then, wave interference techniques to produce holograms have significantly advanced. This includes microwave holography used in radar systems and acoustic holography used in seismic applications.

Research work related to holography has revealed it as a future data storing technology with enormous capacity for storing data along with the ability to read and write huge amounts of data simultaneously. For nine years, Khitun was trying to develop spin wave based logic circuits similar to those used in computers.

However, last year, Khitun finally decided it might not be necessary for the new device to replace the electronic circuits in a computer. Rather, the device could be made to complement the circuits. This was a critical moment for Khitun.

As outlined in their paper, the researchers conducted an experiment using a prototype device consisting of a 2-bit holographic memory. They aligned a pair of magnets symbolizing the memory elements, in various positions on the magnetic waveguides.

The magnetic field from the magnets affects the spin waves that propagate through the waveguide. At room temperature, when the researchers applied spin waves interference they got a clear picture, in which they were able to recognize the magnetic states of the magnets.