Researchers from MIT, Harvard University, and the U.S. Army have built a compact device the size of a shoebox that works at room temperature to produce a terahertz laser with a frequency that can be tuned over a wide range. The big deal with the T-ray machine that the team has built is that it is the size of a shoebox.
Normally such machines require large, bulky setup and often have to operate at ultracold temperatures. The device that the researchers built uses off-the-shelf parts and is designed to generate terahertz waves by spinning up the energy of molecules in nitrous oxide or laughing gas.
The T-ray vision isn’t the only thing the terahertz waves may be useful for. Terahertz waves may also be usable for a form of wireless communication that carries information at a higher bandwidth than radar and can do so across distances that scientists can tune.
The device the team built uses an infrared source called a quantum cascade laser or QCL. This laser is a more recent development that is compact and tunable. When searching for gas, the team landed on nitrous oxide pumped into a pen-sized cavity. The team can create similar systems using other gas molecules like carbon monoxide and ammonia paired with a QCL matched to each gas.
The results of all the research has led to the confirmation of the universal concept of a terahertz laser source that can be broadly tunable across its entire rotational states when pumped by a continuously tunable QCL, according to researcher Fan Wang. The research was supported by the U.S. Army Research Office and the National Science Foundation.