Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Tailored for Optical Applications

09.11.2007
Coordination polymers as materials with very high birefringence

When a calcite crystal is placed onto a printed page, the letters appear doubled. This is the result of a property called birefringence. Scientists at the Simon Fraser University in Canada have now developed a material that is among the most birefringent solids ever observed. As described in the journal Angewandte Chemie, this material is not a mineral, but rather a coordination polymer.

Refraction is the change in direction of a wave of light when it passes from air into water or a crystal. It is caused by a local change in the speed of propagation. In the case of birefringence, the light is divided into two perpendicularly polarized beams, which move at different speeds and exit the material shifted relative to each other. The source of this effect is a crystal lattice that has different optical properties along its various axes (anisotropy).

Birefringent optical components are usually made of calcite. The critical value for these applications is the difference in the refractive index of light in two directions in the crystal, the birefringence, which is 0.17 for calcite.

... more about:
»birefringence »birefringent

The team led by Daniel B. Leznoff and Zuo-Guang Ye has now produced a highly birefringent coordination polymer. Coordination polymers are one-, two-, or three-dimensional bridged metal complexes. The advantage to this type of compound is the limitless number of design possibilities: The individual components—metal center, chelating ligands, and bridging ligands—can be selected and combined almost at will to get the desired material properties.

Leznoff’s team, spearheaded in the lab by Michael J. Katz, decided to use a “terpy” ligand, a flat ring system consisting of three pyridine units (six-membered aromatic rings with one nitrogen atom), and lead as the metal center. The complexes are linked by linear bridging ligands made of a central silver or gold ion and two cyanide groups to form two-dimensional layers. If the central lead atom is replaced with manganese, one-dimensional ladder-like structures are formed. Within their crystals, however, the lead and manganese polymers have analogous arrangements: the terpy molecules are piled up plane-to-plane, perpendicular to the axis of crystal growth. This is clearly the crucial factor leading to the high birefringence, which reaches values from 0.43 to just under 0.4, significantly higher than those of the numerous inorganic birefringent materials.

Improved optical data storage and data transfer in communications technology are possible applications for such highly birefringent materials.

Author: Daniel B. Leznoff, Simon Fraser University (Canada), http://www.sfu.ca/leznoffgroup/

Title: Highly Birefringent Materials Designed Using Coordination-Polymer Synthetic Methodology

Angewandte Chemie International Edition 2007, 46, No. 46, 8804–8807, doi: 10.1002/anie.200702885

Daniel B. Leznoff | Angewandte Chemie
Further information:
http://www.sfu.ca/leznoffgroup/
http://pressroom.angewandte.org

Further reports about: birefringence birefringent

More articles from Life Sciences:

nachricht Bioenergy cropland expansion could be as bad for biodiversity as climate change
11.12.2018 | Senckenberg Forschungsinstitut und Naturmuseen

nachricht How glial cells develop in the brain from neural precursor cells
11.12.2018 | Universitätsmedizin der Johannes Gutenberg-Universität Mainz

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Topological material switched off and on for the first time

Key advance for future topological transistors

Over the last decade, there has been much excitement about the discovery, recognised by the Nobel Prize in Physics only two years ago, that there are two types...

Im Focus: Researchers develop method to transfer entire 2D circuits to any smooth surface

What if a sensor sensing a thing could be part of the thing itself? Rice University engineers believe they have a two-dimensional solution to do just that.

Rice engineers led by materials scientists Pulickel Ajayan and Jun Lou have developed a method to make atom-flat sensors that seamlessly integrate with devices...

Im Focus: Three components on one chip

Scientists at the University of Stuttgart and the Karlsruhe Institute of Technology (KIT) succeed in important further development on the way to quantum Computers.

Quantum computers one day should be able to solve certain computing problems much faster than a classical computer. One of the most promising approaches is...

Im Focus: Substitute for rare earth metal oxides

New Project SNAPSTER: Novel luminescent materials by encapsulating phosphorescent metal clusters with organic liquid crystals

Nowadays energy conversion in lighting and optoelectronic devices requires the use of rare earth oxides.

Im Focus: A bit of a stretch... material that thickens as it's pulled

Scientists have discovered the first synthetic material that becomes thicker - at the molecular level - as it is stretched.

Researchers led by Dr Devesh Mistry from the University of Leeds discovered a new non-porous material that has unique and inherent "auxetic" stretching...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

New Plastics Economy Investor Forum - Meeting Point for Innovations

10.12.2018 | Event News

EGU 2019 meeting: Media registration now open

06.12.2018 | Event News

Expert Panel on the Future of HPC in Engineering

03.12.2018 | Event News

 
Latest News

Electronic evidence of non-Fermi liquid behaviors in an iron-based superconductor

11.12.2018 | Physics and Astronomy

Topological material switched off and on for the first time

11.12.2018 | Materials Sciences

NIST's antenna evaluation method could help boost 5G network capacity and cut costs

11.12.2018 | Information Technology

VideoLinks
Science & Research
Overview of more VideoLinks >>>