ARROW principle enables atomic spectroscopy on a chip

Researchers at the University of California, Santa Cruz, and Brigham Young University (BYU; Provo, UT) have reported successful atomic spectroscopy with integrated optics on a chip for the first time, guiding a beam of light through a rubidium-vapor cell integrated into a semiconductor chip. Potential applications include frequency stabilization for lasers, gas-detection sensors, and quantum information processing. “To stabilize lasers, people use precision spectroscopy with bulk rubidium-vapor cells. We could build a little integrated frequency-stabilization chip that would do that more easily than a conventional frequency-stabilization circuit,” said Holger Schmidt, at UC Santa Cruz, who co-led the research effort with Aaron Hawkins of BYU.

The key to the researchers’ achievement is their development of hollow-core optical waveguides based on antiresonant reflecting optical-waveguide (ARROW) principles (see www.laserfocusworld.com/articles/218569). To perform atomic spectroscopy, the researchers incorporated rubidium reservoirs into a chip, connecting the reservoirs to hollow-core waveguides so that the optical beam path was filled with rubidium atoms. The resulting vapor cell was completely self-contained and had an active cell volume about 80 million times smaller than a conventional cell. “We used rubidium as a proof of principle, but this technique is applicable to any gaseous medium. So it has potentially far-reaching implications,” Schmidt said. Contact Holger Schmidt at [email protected].