Olching, Germany, Oct. 26, 2004--Laser Components GmbH has commercially introduced a terahertz quantum-cascade laser for both spectoscopic and security applications.
Until recently, the word "terahertz" was mostly used when referring to yet-to-come data-transmission rates in telecommunications. The development of experimental optoelectronic systems using terahertz radiation for weapons and explosives screening, however, has made a technically savvy segment of the public aware of the properties of terahertz radiation. In an edition of the German magazine Der Spiegel, the cover headline read, "Splitternackt auf dem Monitor," which translates as "Stark naked on the monitor."
The terahertz range covers approximately 0.1 to 10 THz; 1 THz is equivalent to 33 wave numbers, 300 µm, or 4 meV. Not only can terahertz radiation pick up spectroscopic resonances in gases, liquids, soft materials, and crystalline materials, but it is also transparent to a whole set of liquids and solids, allowing it too see through many opaque objects such as matchboxes, suitcases, and clothing.
Terahertz radiation is usually obtained through nonlinear effects (second-harmonic generation) or by means of an Auston switch and femtosecond stimulation. Direct terahertz sources, for example diode lasers based on quantum-cascade-laser (QCL) technology, were until recently mostly only available as laboratory prototypes. In April 2004, Laser Components and Alpes Lasers (Neuchâtel, Switzerland) teamed together to combine efforts to increase awareness and provide QCL terahertz products.
Starting in October 2004, a terahertz-laser module called the Quanta Tera will be commercially available from Laser Components; the first experiments with this new laser could be taking place before the end of the year.
The source comprises an existing Quanta OEM QCL driver module and a liquid-nitrogen-cooled QCL that supplies pulsed terahertz waves. Peak performance is in the milliwatt range, with the first wavelength recorded at 86 µm. An adapter couples the driver module to the laser.
The design and development team aimed to use existing proven components such as the Quanta driver module and simple unregulated dewars used with detectors. This keeps costs down, reduces project times, and makes the terahertz laser affordable to a broad group of users. An enhanced device could involve the use of a helium cryostat that would increase the power output tenfold and may also make continuous-wave operation possible, although this version would be quite pricey.