Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Researchers Trap Light, Improve Laser Potential of MEH-PPV Polymer

18.03.2013
Researchers from North Carolina State University have come up with a low-cost way to enhance a polymer called MEH-PPV’s ability to confine light, advancing efforts to use the material to convert electricity into laser light for use in photonic devices.

“Think of a garden hose. If it has holes in it, water springs out through a million tiny leaks. But if you can eliminate those leaks, you confine the water in the hose and improve the water pressure. We’ve plugged the holes that were allowing light to leak out of the MEH-PPV,” says Dr. Lewis Reynolds, a teaching associate professor of materials science and engineering at NC State and co-author of a paper describing the research.

MEH-PPV is a low-cost polymer that can be integrated with silicon chips, and researchers have long sought to use the material to convert electricity into laser light for use in photonic devices such as optical amplifiers and chemical sensors. However, attempts to do this have failed because the amount of electricity needed to generate laser light in MEH-PPV was so high that it caused the material to degrade.

Now researchers have developed an inexpensive way to confine more light in the material, which lowers the energy threshold needed to produce focused laser light by 50 percent. The researchers did this by sandwiching the MEH-PPV between two materials that have matching indices of refraction, efficiently reflecting light back into the MEH-PPV and preventing light from escaping. This results in lower thresholds for laser light.

“This approach is fairly inexpensive and could also be easily scaled up for large-scale processing,” Reynolds says.

The “sandwich” also makes the material more stable by limiting the MEH-PPV’s exposure to oxygen. This makes the material less subject to degradation due to photo-oxidation, which occurs when materials are exposed to both light and oxygen.

“This is a meaningful step forward for low-cost fabrication of these devices, but further optimization is required,” says Dr. Zach Lampert, a former Ph.D. student at NC State and lead author of the paper. “We’re working on that now.”

The paper, “Enhancement of optical gain and amplified spontaneous emission due to waveguide geometry in the conjugated polymer poly[2-methoxy-5-(2'-ethylhexyloxy)-p-phenylene vinylene],” is published online in Applied Physics Letters. The paper was co-authored by Dr. John Papanikolas of the University of North Carolina at Chapel Hill.

-shipman-

Note to Editors: The study abstract follows.

“Enhancement of optical gain and amplified spontaneous emission due to waveguide geometry in the conjugated polymer poly[2-methoxy-5-(2'-ethylhexyloxy)-p-phenylene vinylene]”

Authors: Zach E. Lampert and C. Lewis Reynolds, Jr., North Carolina State University; John M. Papanikolas University of North Carolina at Chapel Hill

Published: February 2013, Applied Physics Letters

Abstract: We report enhanced amplified spontaneous emission (ASE) and optical gain performance in a conjugated polymer (CP)-based thin film waveguide (WG) Si(100)/SiO2/poly[2-methoxy-5-(20-ethylhexyloxy)-p-phenylene vinylene] (MEH-PPV) by encapsulating the active layer with a transparent dielectric film of poly(methyl methacrylate) (PMMA). With index matched SiO2 and PMMA claddings, symmetric WGs are formed that exhibit increased mode confinement and reduced propagation loss enabling lower ASE threshold (40%) and higher optical gain (50%) compared to Si(100)/SiO2/MEH-PPV/air asymmetric WGs. An extremely large net gain coefficient of 500 cm_1 is achieved under picosecond pulse excitation, which is >4_ larger than values previously reported in the literature. Fabrication of symmetric WGs requires no complex processing techniques, thus offering a simple, low-cost approach for effectively controlling the ASE behavior of CP-based WGs and related optical devices.

Matt Shipman | EurekAlert!
Further information:
http://www.ncsu.edu

More articles from Physics and Astronomy:

nachricht Hope to discover sure signs of life on Mars? New research says look for the element vanadium
22.09.2017 | University of Kansas

nachricht Calculating quietness
22.09.2017 | Forschungszentrum MATHEON ECMath

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

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

Im Focus: The pyrenoid is a carbon-fixing liquid droplet

Plants and algae use the enzyme Rubisco to fix carbon dioxide, removing it from the atmosphere and converting it into biomass. Algae have figured out a way to increase the efficiency of carbon fixation. They gather most of their Rubisco into a ball-shaped microcompartment called the pyrenoid, which they flood with a high local concentration of carbon dioxide. A team of scientists at Princeton University, the Carnegie Institution for Science, Stanford University and the Max Plank Institute of Biochemistry have unravelled the mysteries of how the pyrenoid is assembled. These insights can help to engineer crops that remove more carbon dioxide from the atmosphere while producing more food.

A warming planet

Im Focus: Highly precise wiring in the Cerebral Cortex

Our brains house extremely complex neuronal circuits, whose detailed structures are still largely unknown. This is especially true for the so-called cerebral cortex of mammals, where among other things vision, thoughts or spatial orientation are being computed. Here the rules by which nerve cells are connected to each other are only partly understood. A team of scientists around Moritz Helmstaedter at the Frankfiurt Max Planck Institute for Brain Research and Helene Schmidt (Humboldt University in Berlin) have now discovered a surprisingly precise nerve cell connectivity pattern in the part of the cerebral cortex that is responsible for orienting the individual animal or human in space.

The researchers report online in Nature (Schmidt et al., 2017. Axonal synapse sorting in medial entorhinal cortex, DOI: 10.1038/nature24005) that synapses in...

Im Focus: Tiny lasers from a gallery of whispers

New technique promises tunable laser devices

Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...

Im Focus: Ultrafast snapshots of relaxing electrons in solids

Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!

When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...

Im Focus: Quantum Sensors Decipher Magnetic Ordering in a New Semiconducting Material

For the first time, physicists have successfully imaged spiral magnetic ordering in a multiferroic material. These materials are considered highly promising candidates for future data storage media. The researchers were able to prove their findings using unique quantum sensors that were developed at Basel University and that can analyze electromagnetic fields on the nanometer scale. The results – obtained by scientists from the University of Basel’s Department of Physics, the Swiss Nanoscience Institute, the University of Montpellier and several laboratories from University Paris-Saclay – were recently published in the journal Nature.

Multiferroics are materials that simultaneously react to electric and magnetic fields. These two properties are rarely found together, and their combined...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

“Lasers in Composites Symposium” in Aachen – from Science to Application

19.09.2017 | Event News

I-ESA 2018 – Call for Papers

12.09.2017 | Event News

EMBO at Basel Life, a new conference on current and emerging life science research

06.09.2017 | Event News

 
Latest News

Rainbow colors reveal cell history: Uncovering β-cell heterogeneity

22.09.2017 | Life Sciences

Penn first in world to treat patient with new radiation technology

22.09.2017 | Medical Engineering

Calculating quietness

22.09.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>