Bell Labs Builds Novel Semiconductor Laser Using Photonic Crystal

Researchers at Bell Labs have developed a novel semiconductor laser based on a photonic crystal that was made in collaboration with scientists from the New Jersey Nanotechnology Consortium, California Institute of Technology and Harvard University. Potential applications for the small, surface-emitting laser include advanced optical communications to sensitive chemical detectors. In particular, large arrays of devices might be produced on a single chip, each with its own designed emission properties.


Bell Labs said the development leverages its work in quantum cascade (QC) lasers, which are made by stacking many ultra thin atomic layers of standard semiconductor materials on top of each other. By varying the thickness of the layers, it is possible to select the particular wavelength at which a QC laser will emit light, allowing scientists to custom design a laser.


Unlike a QC laser, the new device uses a photonic crystal that enables it to emit photons perpendicular to the semiconductor layers, resulting in a laser that emits light through its surface. Photonic crystals are materials with repeating patterns spaced very close to one another, with separations between the patterns comparable to the wavelengths of light. When light falls on such a patterned material, the photons of light interact with it, and with proper design of the patterns, it is possible to control and manipulate the propagation of light within the material. Using an electron beam lithography facility at the New Jersey Nanotechnology Consortium, the researchers were able to superimpose a hexagonal photonic crystal pattern on the semiconductor layers that made the QC laser.


The research has been published on the Web by the journal Science.
http://www.lucent.com/press/1003/031031.nsa.htmlhttp://www.njnano.org