Science News
from research organizations

Researchers Bend Light Through Waveguides In Colloidal Crystals

Date:
January 9, 2008
Source:
University of Illinois at Urbana-Champaign
Summary:
Researchers have achieved optical waveguiding of near-infrared light through features embedded in self-assembled, three-dimensional photonic crystals. Applications for the optically active crystals include low-loss waveguides, low-threshold lasers and on-chip optical circuitry.
Share:
       
Total shares:  
FULL STORY

Researchers at the University of Illinois are the first to achieve optical waveguiding of near-infrared light through features embedded in self-assembled, three-dimensional photonic crystals. Applications for the optically active crystals include low-loss waveguides, low-threshold lasers and on-chip optical circuitry.
Credit: Photo by L. Brian Stauffer

Researchers at the University of Illinois are the first to achieve optical waveguiding of near-infrared light through features embedded in self-assembled, three-dimensional photonic crystals. Applications for the optically active crystals include low-loss waveguides, low-threshold lasers and on-chip optical circuitry.

Key to the fabrication technique -- which uses multi-photon polymerization and a laser scanning confocal microscope -- is a self-assembled, colloidal material that exhibits a photonic band gap, said Paul Braun, a University Scholar and professor of materials science and engineering.

In previous work, reported in 2002, Braun's research group was the first to show that through multi-photon polymerization they could embed a polymer feature inside a silicon dioxide, self-assembled colloidal crystal.

Braun and his team demonstrate actual optical activity in waveguides and cavities created in their colloidal crystals.

"Taking our earlier work as a starting point, we built upon recent advances in theory and computation, improvements in materials growth techniques, and better colloidal crystallization capabilities to produce this new photonic material," said Braun, who also is affiliated with the university's Beckman Institute, Frederick Seitz Materials Research Laboratory, and Micro and Nanotechnology Laboratory.

To make their optically active devices, the researchers begin by assembling a colloidal crystal of uniform silica spheres that are 900 nanometers in diameter. After removing the solvent, the researchers fill the spaces between the spheres with a photoactive monomer. Then they shine laser light through a microscope and into the crystal, polymerizing the monomer at the desired locations.

Next, they remove the unpolymerized liquid, and then fill the structure with silicon. Finally, they etch away the silica spheres, leaving the desired optical features embedded in a three-dimensional photonic crystal.

"Using spheres 900 nanometers in diameter creates a band gap at 1.5 microns, which is the wavelength used by the telecommunications industry for transmissions through fiber-optical cables," Braun said. "Creating these waveguides by coupling colloidal assembly and multi-photon polymerization is simpler and less expensive than conventional fabrication techniques, especially for large-area photonic crystals."

This research has been accepted for publication in Nature Photonics, and is posted on the journal's Web site.

With Braun, co-authors of the paper are Stephanie A. Rinne, a postdoctoral fellow at the Beckman Institute, and Florencio García-Santamaría, a postdoctoral research associate in the department of materials science and engineering.

The work was funded by the U.S. Army Research Office, National Science Foundation and the U.S. Department of Energy.


Story Source:

The above story is based on materials provided by University of Illinois at Urbana-Champaign. Note: Materials may be edited for content and length.


Cite This Page:

University of Illinois at Urbana-Champaign. "Researchers Bend Light Through Waveguides In Colloidal Crystals." ScienceDaily. ScienceDaily, 9 January 2008. <www.sciencedaily.com/releases/2008/01/080107121928.htm>.
University of Illinois at Urbana-Champaign. (2008, January 9). Researchers Bend Light Through Waveguides In Colloidal Crystals. ScienceDaily. Retrieved May 22, 2015 from www.sciencedaily.com/releases/2008/01/080107121928.htm
University of Illinois at Urbana-Champaign. "Researchers Bend Light Through Waveguides In Colloidal Crystals." ScienceDaily. www.sciencedaily.com/releases/2008/01/080107121928.htm (accessed May 22, 2015).

Share This Page:


Matter & Energy News
May 22, 2015

Latest Headlines
updated 12:56 pm ET