Search Menu
Photonics Media Photonics Buyers' Guide Photonics EDU Photonics Spectra BioPhotonics EuroPhotonics Industrial Photonics Photonics Showcase Photonics ProdSpec Photonics Handbook
More News
Email Facebook Twitter Google+ LinkedIn Comments

Image Storage, but Not Without Delay

Photonics Spectra
Feb 2007
Slow and steady really does win, according to University of Rochester researchers. The group slowed images carried on photon pulses in a hot gas of atoms and then showed that the image information was preserved. As described in the Jan. 26 issue of Applied Physics Letters, this go-slow, all-optical image delay could find use in image processing, holography, optical pattern correlation, remote sensing and quantum information.

For example, image processing requires a buffer. One solution is to convert the image to its electronic equivalent, but because that demands lots of light, information is lost. Another solution is a long delay line, but that suffers from diffraction and space limitations. A small all-optical buffer, which the investigators’ technique enables, would solve these problems.

The researchers made use of the atomic resonances of cesium to slow light of a particular frequency. Such slow-light materials have a slow group velocity, the speed at which energy travels, because they are highly dispersive due to frequency-dependent absorption. An advantage to the cesium-based approach is that it requires only a single laser, unlike the multiple sources needed for other slow-light methods.

In one experiment, the scientists sent 2-ns light pulses with, on average, less than one photon each through a mask and a lens-based imaging system. Between the lenses sat a 10-cm cell full of hot cesium vapor. By changing the cesium’s temperature, the researchers produced a variable delay of up to 10 ns.

After the light pulses traversed the setup, the group captured them with a scanning optical fiber and a camera, taking many seconds to move across the entire array of positions. They did this for a delayed and nondelayed two-dimensional image of a pair of letters, demonstrating similar image fidelity and resolution no matter the delay.

So far, the group has achieved delays of up to 100 ns. Immediate plans are to slow dozens of pulses several milliseconds, but the eventual goal is to achieve far longer delays.

The technology of generating and harnessing light and other forms of radiant energy whose quantum unit is the photon. The science includes light emission, transmission, deflection, amplification and detection by optical components and instruments, lasers and other light sources, fiber optics, electro-optical instrumentation, related hardware and electronics, and sophisticated systems. The range of applications of photonics extends from energy generation to detection to communications and...
As We Go To PressatomsBasic ScienceBiophotonicsBreaking Newsnanophoton pulsesphotonicsPresstime BulletinUniversity of Rochester

Terms & Conditions Privacy Policy About Us Contact Us
back to top
Facebook Twitter Instagram LinkedIn YouTube RSS
©2018 Photonics Media, 100 West St., Pittsfield, MA, 01201 USA,

Photonics Media, Laurin Publishing
x Subscribe to Photonics Spectra magazine - FREE!
We use cookies to improve user experience and analyze our website traffic as stated in our Privacy Policy. By using this website, you agree to the use of cookies unless you have disabled them.