A stubborn crystal compound may enable better fiber optics and long range biological and chemical weapon detection systems, thanks to the tenacity of Northwestern University and Argonne National Laboratory scientists. The researchers used the ChemMatCARS beamline, the most powerful x-ray diffraction machine in the western hemisphere, to peer into the structure of the new wonder optical material.

The crystal compound previously kept scientists frustrated with its needle-like and difficult to study structure. However, part of the compound's promise lies within that structure because it makes it an ideal candidate for use in fiber optics. The compound is made from various elements including phosphorous, selenium and zirconium with the inclusion of one of cesium, potassium or rubidium, shown as (A)ZrPSe6 where A is one of the latter three.

“Like other such materials, this material has an electrically polarized structure,” explains Argonne scientist Mercouri Kanatzidis. “The incident light interacts with the electron cloud and in the process is disturbed. The disturbance changes the wavelength of the emitted light and creates two beams: the original and the second harmonic — a beam with half the wavelength and double the frequency.”

The crystal's physical structure and its high-power harmonic beam fit together with another of its properties, very high transparency, to produce a very promising new optical material.

The group's work has been published in a paper in the Journal of the American Chemical Society in issue 37 of this year.