Atomic spectroscopy on a chip
Kristina Kirby
Source: University of California, Santa Cruz
Atomic spectroscopy on a chip
http://www.nanowerk.com/news/newsid=2018.php
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(Nanowerk News) Researchers at the University of California, Santa
Cruz, have performed 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.
Atomic spectroscopy is a widely used technique with diverse
applications. Based on the interactions of light and matter,
spectroscopy is often used to identify substances by the wavelengths
of light they absorb or emit. Conventional systems have many large
components, whereas the compact, fully planar device developed at UCSC
enables the study of atoms and molecules on a chip-based platform with
integrated optics, said Holger Schmidt, associate professor of
electrical engineering.
Schmidt's group and his collaborators at Brigham Young University
described the first monolithically integrated, planar rubidium cell on
a chip in a paper published in the June issue of Nature Photonics. The
first author of the paper is Wenge Yang, a postdoctoral researcher in
Schmidt's lab at UCSC's Baskin School of Engineering.
According to Schmidt, potential applications for this technology
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," Schmidt said.
That project is already under way in Schmidt's lab. Other
applications, such as quantum information processing, are more long-
term goals, he said.
The key to the group's achievement is their development of hollow-core
optical waveguides based on antiresonant reflecting optical waveguide
(ARROW) principles. In previous publications, Schmidt and his
collaborators have described other uses of ARROW waveguides integrated
into chips using standard silicon fabrication technology.
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 is filled with rubidium
atoms. The resulting vapor cell is completely self-contained and has
an active cell volume about 80 million times smaller than a
conventional cell, Schmidt said.
"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.
In addition to its use in laser frequency stabilization, rubidium
vapor is widely used in quantum optics experiments and has been used
to slow the speed of light.
"Fundamental concepts in quantum information processing have been
demonstrated in principle using bulk rubidium systems. To be practical
you can't have big optical tables in all the places you would want to
use it, but now we can make this technology more compact and
portable," Schmidt said.
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http://www.nanowerk.com/news/newsid=2018.php
Source: University of California, Santa Cruz