Improving Polymer's Ability to Capture Light

Guest_Jim_* - April 1, 2013 05:21AM in Science & Technology

The ability to produce laser light is very valuable for photonic technologies, as laser light consists of a pure frequency. Producing these photons at low powers however is not always easy, but the polymer, MEH-PPV, could help if it did not leak so much light. Researchers at North Carolina State University have found a way to seal the polymer's holes and this should reduce the energy needed to create laser light by 50%.

Most people think of 'laser' as just a word, but it is actually a fairly descriptive acronym for the lasing process. Light Amplification by Stimulate Emission of Radiation, LASER, means that a signal of light is amplified by releasing additional photons that reinforce it. This happens naturally in some materials as energized electrons will drop energy levels, releasing a photon of the same frequency as that which stimulated the electron to fall. As the photons have the same frequency, the signal is amplified by the additional photons.

The MEH-PPV polymer is a low cost material capable of lasing that can be integrated with silicon electronics but has the critical flaw of letting photons escape, which means there are fewer photons to form the laser and fewer to trigger the emission of more. What the researchers have done is sandwiched it between materials with matching indices of refraction so that what light escapes is reflected back in, and by keeping more photons in the material, less energy is needed to initiate lasing.

Source: North Carolina State University