Researchers at the National Institute of Standards and Technology (NIST; Boulder, CO) have fabricated a prototype saturation-absorption spectrometer that is about the size of a green pea and consists of miniature optics, a microfabricated vapor cell, heaters, and a photodetector, all within a cube about 10 mm on a side. The system could be used to provide a stable optical frequency at 795, 780, 895, or 852 nm by locking a single-mode diode laser to an atomic transition in rubidium or cesium atoms, or to provide frequency stabilization of telecom lasers between 1540 and 1590 nm by adding a periodically poled lithium niobate waveguide, according to the researchers. It might also be extended to other atoms and molecules such as potassium or iodine.
Most of the optical components are commercially available and the sample chambers can be mass-produced from silicon wafers, requiring less power and potentially lower cost than the traditional blown-glass containers used in laboratories. Tests by NIST predict that the stability and signal performance of the tiny, portable device can be comparable to standard tabletop setups. Contact Svenja A. Knappe at [email protected].