First ‘metasurface’ high-power terahertz laser

Jan 17, 2016

A semiconductor laser that works at terahertz frequencies has been developed at UCLA Henry Samueli School of Engineering and Applied Science. 

The innovative project could help in developing lasers for space exploration, military applications, and law enforcement. The terahertz waves could be used to analyze clothing, semiconductors, plastics and other works of art without damaging the materials being examined.

Benjamin Williams and his team at UCLA have created the first vertical external cavity surface emitting laser that operates at terahertz range, also known as VECSEL. It would provide a route to have higher output powers with excellent beam quality in the terahertz range simultaneously. This approach will allow scientists to engineer the beam to have the desired shape, polarization and spectral properties. VECSEL is made up of an array of many small antenna laser cavities coupled together such that when a terahertz wave hits the array, it is reflected as if it were being reflected from a flat mirror and doesn’t see the cavities. 

For semiconductor lasers creating a beam that is straight and symmetrical over large distances and changing thermal conditions is challenging, but it’s quite possible for terahertz quantum cascade lasers that use metal laser cavities with dimensions much smaller than the wavelength. The researchers are working on several new designs to further advance the technology.

Source: http://nextbigfuture.com/2015/12/ucla-creates-terahertz-lasers-with.html