Physicists Add 11 Colours to the Rainbow By Tearing Apart Atoms

By Andrew Tarantola on at

True, the pink is a lie. But a UC Santa Barbara research team has honestly just generated eleven new hues using lasers and ion cascades.

The team created the new colours by aiming a pair of lasers—one high-frequency, the other low-frequency—at a slab of semiconductor material, a gallium arsenide nanostructure. The high-frequency beam separates an electron from its host atom, generating what's known as an excitron (a bonded pair consisting of a negatively-charged electron and a positively-charged ion). The powerful, low frequency wave then accelerates the freed electron, which goes crashing into the electron-less atom in front of it. Since the electron has extra energy from the acceleration when it recombines with the ion in front of it, that energy is radiated as light. Previously unseen frequencies of light.

Physicists Add 11 Colors to the Rainbow By Tearing Apart Atoms

While the general public might not be ready yet to comprehend the colour blorange, this technique could prove quite useful in high-speed data transfers. As Ben Zaks, a UCSB doctoral student in physics and the paper's lead author, explained to Science Daily,

Think of your cable Internet. The cable is a bundle of fiber optics, and you're sending a beam with a wavelength that's approximately 1.5 microns down the line. But within that beam there are a lot of frequencies separated by small gaps, like a fine-toothed comb. Information going one way moves on one frequency, and information going another way uses another frequency. You want to have a lot of frequencies available, but not too far from one another.

The team hopes to eventually develop this technology to run, not on the free electron laser used in this experiment, but on a transistor operating at terahertz frequencies. "Our data indicates that we are modulating the near infrared laser at twice the terahertz frequency. This is where we could really see this working to increase the speed of optical modulation, which is how you get information down a cable line," Zecks said. [Science Daily - Image: Peter Allen, UCSB]