Diamond-based nanowire devices advance quantum science and technology

Washington, Feb 15 (ANI): A team of scientists at Harvard University has taken another step towards making applications based on quantum science and technology possible, by creating diamond-based nanowire devices.

The research was led by Marko Loncar, Assistant Professor of Electrical Engineering at the Harvard School of Engineering and Applied Sciences (SEAS).

His team found that the performance of a single photon source based on a light emitting defect (color center) in diamond could be improved by nanostructuring the diamond and embedding the defect within a diamond nanowire.

Scientists, in fact, first began exploiting the properties of natural diamonds after learning how to manipulate the electron spin, or intrinsic angular momentum, associated with the nitrogen vacancy (NV) color center of the gem.

The quantum (qubit) state can be initialized and measured using light. The color center "communicates" by emitting and absorbing photons.

The flow of photons emitted from the color center provides a means to carry the resulting information, making the control, capture, and storage of photons essential for any kind of practical communication or computation.

Gathering photons efficiently, however, is difficult since color-centers are embedded deep inside the diamond.

"This presents a major problem if you want to interface a color center and integrate it into real-world applications," said Loncar.

"What was missing was an interface that connects the nano-world of a color center with macro-world of optical fibers and lenses," he added.

The diamond nanowire device offers a solution, providing a natural and efficient interface to probe an individual color center, making it brighter and increasing its sensitivity.

The resulting enhanced optical properties increases photon collection by nearly a factor of ten relative to natural diamond devices.

"Our nanowire device can channel the photons that are emitted and direct them in a convenient way," said lead-author Tom Babinec, a graduate student at SEAS.

The new device offers a bright, stable source of single photons at room temperature, an essential element in making fast and secure computing with light practical.

Further, the diamond nanowire is designed to overcome hurdles that have challenged other state-of-the-art systems-such as those based on fluorescent dye molecules, quantum dots, and carbon nanotubes-as the device can be readily replicated and integrated with a variety of nano-machined structures.

The finding could lead to a new class of nanostructured diamond devices suitable for quantum communication and computing, as well as advance areas ranging from biological and chemical sensing to scientific imaging. (ANI)