Lasers Could Be Used To Store Data

A new way to store data could be on the horizon. A team of scientists are hoping to make new storage devices with lasers.

Data that makes up your pictures and music saved on your computer is saved in binary. Data stored in binary can be stored magnetically, electronically or optically. The main way to do this is either by magnetising certain regions in a magnetic material north or south as little ‘mini’ magnets. Or electronically, by flipping the spin of electrons via a magnetic field. Electrons have an intrinsic spin which can be up or down. By putting the electrons in these states, you can save data as either ‘up’ or ‘down’.

Instead of using electrons, scientists from the SLAC National Accelerator Laboratory and the Massachusettes Institute of Technology (MIT) are using lasers to store information. By using pulses of light, a material can be flipped from one state to another and return to its original state. As a result, a wave of new-generation data storage devices could be in our homes and workplaces very soon. The results were recently published in Science Advances.

Instead of using the electron spin as the material property in question for storing binary information, the team of scientists used charge density waves. These are periodic changes in electronic charge distribution within the material. Tantalum disulphide was used in the recent study for its charge density wave properties. In this material, the density waves are oriented in the same direction, a state known as the alpha state.

With a flash of laser light, the alpha state converted into a beta state where some of the charge density waves shifted direction. Each of the states would be separated by domain walls. Surprisingly, with a second flash of the laser light, the domain walls would go away, and the material would return to a pure alpha state. The experiments were carried out at the SLAC National Accelerator Laboratory using thin samples of tantalum disulphide and SLAC’s ultrafast electron diffraction instrument. It is essentially a high-speed electron camera that can capture really fast processes, including the shifts in atomic structure of the tantalum disulphide when zapped with the laser. The electron camera could also tell the scientists how big the domains were and how they were dispersed through the material.

By varying the temperature of the sample, and the energy of the laser, the way in which the material shifted state could be fine-tuned. The team hope to further their study by experimenting with different laser pulse shapes and see if they can further fine tuning the formation of the domains. With this, the team will be well on their way to making laser based storage devices. Watch this space.

Credit: “Lasers could be used to store data”,, Meriam Berboucha, 28.10.2018, via MIT News.




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