Researchers have nearly doubled the continuous output power of a type of laser called a terahertz quantum cascade laser, with potential applications in medical imaging, airport security and more. The results were published in AIP Advances. Terahertz radiation sits between microwaves and infrared light on the electromagnetic spectrum. It is relatively low-energy and can penetrate materials such as clothing, wood, plastic and ceramics.
The unique qualities of terahertz radiation make it an attractive candidate for imaging, but the ability to produce and control terahertz waves has lagged behind technology for radio, microwave and visible light. Recently, scientists have made rapid progress on a technology to produce terahertz light, called a quantum cascade laser or QCL.
First author Dr. Wang Xuemin from the China Academy of Engineering Physics and colleagues focused on even further increasing the output power of terahertz QCLs, especially in the mode in which the laser output power is continuous. By optimizing the material growth and manufacturing process for terahertz QCLs, Wang and his team made a laser with a record output power of up to 230 milliwatts in continuous wave mode, beating the previous record of 138 milliwatts.
The new laser can also be used in air, Wang said, which is a challenge for lower-powered lasers since particles in the air can scatter or absorb the laser light before it reaches its target. Wang is hopeful that future improvements could bring the laser’s continuous power above one watt, a level previously only attained by terahertz QCLs in pulsed wave mode.
Source: Asian Scientist