Scientists demonstrate high performing room temperature nano laser
Scientists at Yokohama National University in Japan have built a highly efficient room-temperature nanometer-scale laser that produces stable, continuous streams of near-infrared laser light. The overall device has a width of several microns, while the part of the device that actually produces laser light has dimensions at the nanometer scale in all directions. The laser uses only a microwatt of power, one of the smallest operating powers ever achieved. This nanolaser design should be useful in future miniaturized circuits containing optical devices. The researchers present their nanolaser in the latest issue of Optics Express, an open-access journal published by the Optical Society of America (OSA). The laser is made of a semiconductor material known! as gallium indium arsenide phosphate (GaInAsP). The laser's small size and efficiency were made possible by employing a design, first demonstrated at the California Institute of Technology in 1999, known as a photonic-crystal laser. In this design, researchers drill a repeating pattern of holes through the laser material. This pattern is called a photonic crystal. The researchers deliberately introduced an irregularity, or defect, into the crystal pattern, for example by slightly shifting the positions of two holes. Together, the photonic crystal pattern and the defect prevent light waves of most colors (frequencies) from existing in the structure, with the exception of a small band of frequencies that can exist in the region near the defect.