Compact chip-mounted terahertz laser will investigate interstellar medium

Terahertz radiation, which lies between visible light and microwaves in the electromagnetic spectrum, has many potential applications in imaging and detection, but its use has been hampered by the size and power consumption of the equipment needed to generate it. Electrical engineers from MIT in Boston have now published details of a method to etch low-power terahertz lasers onto microchips.

Led by Prof Qing Hu, the method is the culmination of two decades of research. Published in Nature Photonics, the paper explains how Hu and colleagues from Sandia National Laboratory and the University of Toronto refined the design on a type of device called a quantum cascade those that with distributed feedback.

Their major discovery was how to overcome an inherent drawback of this type of laser: they emit light out of the front and back of the substance used to generate the laser, known as the gain medium.