Tiny Chip Could Solve Real-World Problems

Take the dime in your wallet. Now imagine a chip no larger than a fraction of that coin that can detect the faintest traces of thousands of different chemicals, using over 32 different infrared light-emitting lasers.

That chip, the brainchild of applied physics professor Federico Capasso, has seemingly limitless applications—in areas ranging from medicine to intelligence gathering.

Capasso has expanded upon the Quantum Cascade Laser that debuted in 1994 by combining an array of multiple lasers emitting light of varying wavelengths in a tiny, more portable chip.

“Using the array, you can choose to fire a laser wavelength that corresponds to a molecule’s absorption, and when you see how much light has been absorbed, you can see how much of that molecule is present,” said Benjamin G. Lee, Capasso’s research assistant.

This efficient and portable way to sense chemicals—toxic or benign—may make the largest waves in medicine as a noninvasive diagnostic device through “breath analysis.” Its high sensitivity can be manipulated to detect certain chemicals in the breath indicative of conditions including diabetes, ulcers, colon cancer, and cystic fibrosis.

Applications of the laser chip may radiate into environmental sciences, as it will soon monitor the changing concentrations of greenhouse gas emissions, Capasso said. He, along with atmospheric chemistry professor James G. Anderson, plans to collaborate with NASA to send lasers into the stratosphere to study the effects of global warming.

Although quantum cascade lasers are already used to study carbon dioxide concentrations, the new chip with the allows researchers to monitor many different gases at the same time, said research associate Mikhail A. Belkin.

The small laser chip may also be used for intelligence gathering in satellites and planes by detecting whether factories are releasing toxic compounds through their smoke.

“You can see if a factory is creating chemical weapons or not,” Belkin said.

In the pharmaceutical industry, the laser chip may be used to ensure that all pills conform to standards of chemical composition, rendering the current method obsolete, Belkin said.

These myriad real-world applications are exactly what the lasers’ developers said have been working for.

“A lot of the development from ’94 until now has been to make it so that it’s useful commercially,” Lee said.

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