Bending light

Spatially variant photonic crystals gently steer light around a 90-degrees corner. The plastic honeycomb has been 3D printed using a laser. Credit: Jennefir L. Digaum et al./Optics Express

Light goes straight (yes, I know, it follows the curved space-time) and bending it is not easy. Optical fibres are a way to bend light and plastic fibres, used for optical communication in the home (I have them) are particularly good at that. Yet, even plastic fibres cannot be bend too much otherwise the light simply jumps out of the fibre and you lose the signal.

Engineers are at work to create the future of computers where they want to use optical signals to dramatically decrease power consumption and interferences in chips thus increasing density and capacity.

We already have nano laser and nano detectors, but these are still a bit too big in the part needed to actually make them work. Also, connecting various parts of a chip requires the capability to bend the light at sharp angles.

These are the issues that researchers are trying to address.

At the University of Washington in cooperation with Stanford researchers have found a way to create nano lasers just 0.7nm thick that can be embedded in chip to modulate an optical signal. Their power consumption is also minuscole: just 27 nW (5 billions of them would consume the equivalent of the bulb lamp in your kitchen).

In parallel, at the University of Texas and at the University of Central Florida found a way to bend light in a very little space at 90° angles.

They managed to create a honeycomb made of plastic whose refraction index in each of the "combs" forces the light to bend. The honeycomb has been 3D printed using a laser to work at nanometre scale.

These two results are providing some of the tools needed to create optical computers, something we expect to see in the next decade. Not powerful as today's microprocessors but so much less power consuming. A cell phone with a battery lasting a full week is getting on sight!

Author - Roberto Saracco

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