Laser beam

Engineers and applied physicists have laid the foundations for a new type of "plug and play" laser - the Raman injection laser - and in the process, several key innovations in laser technology.

The device combines the advantages of nonlinear optical devices and semiconductor injection lasers with a compact design, and may one day lead to wide-ranging applications in imaging and detection.

Published in the February 24th issue of Nature, the proof of concept model was developed by Mariano Troccoli, Ertugrul Cubukcu and Federico Capasso of the Harvard University Division of Engineering and Applied Sciences working with Alexey Belyanin of Texas A&M University and Deborah L. Sivco and Alfred Y. Cho of Bell Laboratories, Lucent Technologies. The finding was supported in part by Texas A&M's Telecommunications and Informatics Task Force Initiative.

Conventional Raman lasers depend on a fundamental phenomenon in physics called the Raman effect - the change in the frequency of monochromatic light (such as a laser) when it passes through a substance. When light from an intense exciting laser beam, known as the "pump," deflects off the molecules of certain materials, some of the incident photons lose part of their energy. As a result, a secondary laser beam with a frequency shifted from that of the exciting laser emerges from the material.