Tiny spectrometer offers precision laser calibration

May 11, 2007
Tiny spectrometer offers precision laser calibration
Photographed adjacent to an ordinary green pea, NIST's microfabricated spectrometer consists of a tiny container of atoms, a photodetector and miniature optics. Credit: Svenja Knappe/NIST

A tiny device for calibrating or stabilizing precision lasers has been designed and demonstrated at the National Institute of Standards and Technology. The prototype device could replace table-top-sized instruments used for laser calibration in atomic physics research, could better stabilize optical telecommunications channels, and perhaps could replace and improve on the precision of instrumentation used to measure length, chemicals or atmospheric gases.

The new spectrometer, described in the May 7 issue of Optics Express, is the latest in a NIST series of miniaturized optical instruments such as chip-scale atomic clocks and magnetometers. The spectrometer is about the size of a green pea and consists of miniature optics, a microfabricated container for atoms in a gas, heaters and a photodetector, all within a cube about 10 millimeters on a side. The package could be used to calibrate laser instruments, or, if a miniature laser were included in the device, could serve as a wavelength or frequency reference.

Most of the optical components are commercially available. The key to the device is a tiny glass-and-silicon container—designed and fabricated at NIST—that holds a small sample of atoms. The sample chambers were micromachined in a clean room and filled and sealed inside a vacuum to ensure the purity of the atomic gas, but they can be mass-produced from silicon wafers into much smaller sizes, requiring less power and potentially cheaper than the traditional blown-glass containers used in laboratories. Although shrinking container size creates some limitations, NIST scientists have accommodated these difficulties by adding special features, such as heaters to keep more atoms in the gas state. NIST tests predict that the stability and signal performance of the tiny, portable device can be comparable to standard table-top setups.

The instrument works by measuring the intensity of a laser beam after it interacts with the atoms. The amount of light absorbed at a particular wavelength produces a characteristic signature. NIST has demonstrated the spectrometer with rubidium and cesium atoms, which absorb light at infrared, near-visible wavelengths, commonly used in atomic physics research. Different atoms or molecules, such as potassium or iodine, could be used for different applications. Or, a waveguide could be added to the device to double the frequency to stabilize lasers used in fiber-optic telecommunications. The mini-spectrometer would offer greater precision than the physical references now used to separate fiber-optic channels, with the advantage that more channels might be packed into the same spectrum.

Citation: S.A. Knappe, H.G. Robinson and L. Hollberg. Microfabricated saturated absorption laser spectrometer. Optics Express. May 7, 2007.

Source: National Institute of Standards and Technology

Explore further: Research pair create two-atom molecules that are more than a thousand times bigger than typical diatomic molecules

Related Stories

Measuring tiny forces with light

August 25, 2016

Photons are bizarre: They have no mass, but they do have momentum. And that allows researchers to do counterintuitive things with photons, such as using light to push matter around.

NIST's compact gyroscope may turn heads

August 23, 2016

Shrink rays may exist only in science fiction, but similar effects are at work in the real world at the National Institute of Standards and Technology (NIST).

Recommended for you

Understanding nature's patterns with plasmas

August 23, 2016

Patterns abound in nature, from zebra stripes and leopard spots to honeycombs and bands of clouds. Somehow, these patterns form and organize all by themselves. To better understand how, researchers have now created a new ...

Light and matter merge in quantum coupling

August 22, 2016

Where light and matter intersect, the world illuminates. Where light and matter interact so strongly that they become one, they illuminate a world of new physics, according to Rice University scientists.

Stretchy supercapacitors power wearable electronics

August 23, 2016

A future of soft robots that wash your dishes or smart T-shirts that power your cell phone may depend on the development of stretchy power sources. But traditional batteries are thick and rigid—not ideal properties for ...

A new study looks for the cortical conscious network

August 26, 2016

New research published in the New Journal of Physics tries to decompose the structural layers of the cortical network to different hierarchies enabling to identify the network's nucleus, from which our consciousness could ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.