Multiple-quantum-well laser emits CW at 2.7 µm up to -39°C
Researchers at the David Sarnoff Research Center (Princeton, NJ) have demonstrated 2.7-µm CW operation of multiple-quantum-well (MQW) diode lasers at operating temperatures up to 234 K (-39°C). The InGaAsSb/AlGaAsSb devices were grown by molecular-beam epitaxy. Such mid-IR diode lasers may be used as sources for trace-gas sensing because, in general, the absorption strengths of many molecules increase by orders of magnitude moving from near- to mid-IR wavelengths. At the longer wavelengths the fundamental absorption bands of the molecules can be probed, as opposed to the weaker overtones and combination bands present at shorter wavelengths.
According to Sarnoff researcher Ray Martinelli, these MQW devices tend to operate in a dominant single mode over well-defined temperature and current intervals and are, therefore, potentially useful sources in laser absorption spectroscopy. Thermoelectric coolers can be used to reach the operating temperature of 234 K. The InGaAsSb/AlGaAsSb lasers are already being commercialized by Sarnoff for gas-sensing applications.
