In the electromagnetic spectrum, terahertz frequency range lies between microwaves and infrared. Terahertz wave can be detected without damaging the material to be analyzed under the premise of plastic, clothing, semiconductors and art materials, etc., it can also be used to analyze the stars the formation and composition of the planet's atmosphere.
Currently using visible vertical external cavity surface emitting laser (VECSEL) has been widely used to generate high-energy beam, but this technique is not applicable to previously terahertz frequency range. Associate Professor of the University of California, Los Angeles, led by electrical engineering Benjamin Williams ` Development of the first team in the terahertz frequency range of VECSEL. findings recently published in the (Applied Physics Letters) on.
In order to emit high-energy beam VECSEL terahertz frequency range, developed with the Williams team called a 'super-reflective front surface mirror' means VECSEL. This device is so named because it contains a large number of tiny by the array antenna coupled laser cavity consisting of, so that when the terahertz wave passes this array will 'see' not see the laser cavity, it will be reflected back, like being an ordinary mirror reflecting back the same.
'Taking over the material surface and the laser combine for the first time.' Williams said, this method only allows the laser in the THz frequency range of the output more power, but also a high-quality laser beam, and metamaterials It allows researchers to use laser beams to further designed to generate the desired polarization, shape and frequency.
A member of one of the research, first author Xu Luyao (phonetic) further explained: 'by super material surface as part of the outer chamber, we can not only improve the shape of the laser beam, but also through different external cavity design to a laser band to new features such as you can to maximize output power and efficiency of the laser. By using the stand-alone wire polarizer or filter as a second reflecting surface, we simply rotating polarizer. '