Power/Performance Bits: Dec. 8

Light in lieu of wires
In a development that could eventually lead to computers that use optics rather than electricity to carry data, Stanford engineers have designed and built a prism-like device they call an ‘optical link’ that can split a beam of light into different colors and bend the light at right angles.

The optical link is a tiny slice of silicon etched with a pattern that resembles a bar code. When a beam of light is shined at the link, two different wavelengths of light split off at right angles to the input, forming a T shape. This is a big step toward creating a complete system for connecting computer components with light rather than wires, the researchers explained, since light can carry more data than a wire, and it takes less energy to transmit photons than electrons.

In previous work the team developed an algorithm that did two things: It automated the process of designing optical structures and it enabled them to create previously unimaginable, nanoscale structures to control light.

This tiny slice of silicon, etched in Jelena Vuckovic’s lab at Stanford with a pattern that resembles a bar code, is one step on the way toward linking computer components with light instead of wires. (Source: Stanford University)

Now, they are using the algorithm to design, build and test a link compatible with current fiber optic networks.

Spray-on power
According to researchers at the University of Toronto, before long, powering your tablet could be as simple as wrapping it in cling wrap as they have invented a new way to spray solar cells onto flexible surfaces using miniscule light-sensitive materials known as colloidal quantum dots (CQDs). They say this is a major step toward making spray-on solar cells easy and cheap to manufacture.

Solar-sensitive CQDs printed onto a flexible film could be used to coat all kinds of oddly shaped surfaces, from patio furniture to an airplane’s wing. A surface the size of your car’s roof wrapped with CQD-coated film would produce enough energy to power three 100-Watt light bulbs—or 24 compact fluorescents.

They call the system sprayLD, a play on the manufacturing process called ALD, short for atomic layer deposition, in which materials are laid down on a surface one atom-thickness at a time.

Until now, it was only possible to incorporate light-sensitive CQDs onto surfaces through batch processing—an inefficient, slow and expensive assembly-line approach to chemical coating. SprayLD blasts a liquid containing CQDs directly onto flexible surfaces, such as film or plastic, like printing a newspaper by applying ink onto a roll of paper. This roll-to-roll coating method makes incorporating solar cells into existing manufacturing processes much simpler, they added.