Next generation photonic memory devices are light-written, ultrafast and energy efficient

All-optical switching. Data is stored in the form of 'bits', which contains digital 0 (North Poles down) or
 1 (North Poles up). Data writing is achieved by 'switching' the direction of the poles via the application of short laser pulses (in red).
Credit: Eindhoven University of Technology

Lighting is the most energy-efficient way of moving information. However, the light shows a large extent: it is difficult to store.

 As a matter of fact, the data centers mainly depend on the magnetic hard drive. However, in these hard drives, information is transferred to an energy cost which is exploding nowadays. 

Researchers at the Institute of Photographic Integration of the Eindhoven Institute of Technology (TU / E) have developed a 'hybrid technique' that shows the benefits of both light and magnetic hard drives.

 The Ultra-Short (Femtosecond) light pulses allow the data to be written directly into magnetic memory in a fast and highly energy-efficient manner.

 Apart from this, as soon as the information is written (and stored), it leaves the empty space so that the empty memory domain can be filled with new data. 

read more: High-speed supernova reveals earliest moments of a dying star

This research published in Nature Communications promises to revolutionize the data storage process in the future Photonic Integrated Circuits.

The data is stored in the hard drive as 'bits', small magnetic domains with north and south pole. 

The direction of these poles ('magnetization') determines whether the bits have digital 0 or 1.

 The direction of magnetization of related writing is achieved by 'switching'.

Synthetic Ferrimagnetes

Traditionally, switching occurs when the external magnetic field is applied, which will apply the direction of the pole either upwards (1) or below (0). 

Alternatively, switching can be achieved through the application of a small (femtosecond) laser pulse, which is called all-optical switching and results in more efficient and very fast storage of data.

Ph.D. candidate Mark Lelyau of Applied Physics Department of TU / E: 'All-optical switching for data storage has been known for nearly a decade.

 When the most promising material for magnetic light devices - all-optical switching was first seen in ferromagnetic materials - this research area has given a lot of boosts.

 'However, in these materials, many laser pulses are required for switching of magnetism and, thus, long data writing time.

Store data one thousand times faster

Under the guidance of Reinoud Lavrijsen and Bert Koopmans were able to obtain all-optical switching in synthetic ferrimagnets - a material system that is highly suitable for Spintronic data applications - using single femtosecond laser applications, thus writing data Exploitation of high velocity. And reduce energy consumption.

So how does all-optical switching compare modern magnetic storage technologies? Laliou: "The switching of magnetization direction by using single pulse all-optical switching is in the order of a picosecond, which is about 100 to 1000 times faster than possible with today's technology. 

Also, as the optical information is stored In magnetic bits without the need for energy-cost electronics, this photonic has a lot of potential for future use in integrated circuits. "

Writing 'On-the-Fly' Data

In addition, integrated all-optical switching with the so-called racetrack memory - a magnetic wire through which data is efficiently transported using an electric current in the form of magnetic bits.


 In this system, magnetic bits are used continuously by using light and are immediately carried with electrical current through the wire, leaving space for empty magnetic bits and, thus, new data to be stored.

Koopmans: Without any intermediate electronic steps, copying information between light and magnetic racetrack, on the fly, "this" is similar to extending from one moving the high-speed train to another. Photonic Thalys' to 'Magnetic ICE'. 

'Without any interference, you will understand the huge increase in the consumption and energy consumption that can be achieved in this way.'

What will happen next? This research was done on the micrometric wires. In the future, small appliances on the nanometer scale should be designed for better integration on chips.

 Apart from this, while working towards the final integration of photonic memory devices, the Physics of the nanostructural group is currently busy investigating the read-out of the magnetic data, which can also be done all-optically.