Researchers have developed a fast and energy-efficient laser writing method for producing high-density nanostructures in silica glass. These tiny structures can be used for long-term five-dimensional (5D) optical data storage at more than 10,000 times the density of Blu-ray Disc storage technology.
Yuhao Lei, a doctoral researcher at the University of Southampton, UK, said: “Individuals and organisations are generating increasingly larger datasets, and there is an urgent need for more efficient forms of data storage with high capacity, low energy consumption and longevity. Although cloud-based The system is more designed for temporary data, but we believe 5D data storage in glass could be useful for long-term data storage in national archives, museums, libraries or private organizations.”
In the study, published in the journal Optica, Lei and his colleagues describe the new method for writing data that contains two optical dimensions plus three spatial dimensions. This new method can write at 1 million voxels per second, which equates to about 230 kilobytes of data per second (over 100 pages of text).
“The physical mechanism we used is universal. Therefore, we anticipate that this energy-efficient writing method can also be used for fast nanostructuring in transparent materials for applications in three-dimensional integrated optics and microfluidics,” Lei said.
Although 5D optical data storage in transparent materials has been demonstrated before, writing data fast enough and high enough density has proven challenging for real-world applications. To overcome this hurdle, the researchers used a high repetition rate femtosecond laser to create tiny pits containing individual nanoscale structures, each measuring just 500 by 50 nanometers.
Instead of writing directly on glass using femtosecond lasers, the researchers used light to create an optical phenomenon known as near-field enhancement, in which several faint pulses of light are passed from one pulse to another. A nanoramera-like structure was created in the isotropic nanoworms produced by the microblast. Using near-field enhancement techniques to fabricate nanostructures minimizes thermal damage that is problematic for other methods using high repetition rate lasers.