Researchers from Thales Corporate Research in Orsay, France, have developed a GaAs-based quantum cascade laser that operates at room temperature. Since their development in 1995, quantum cascade lasers have found applications in gas sensing and infrared spectroscopy. GaAs-based devices had been limited to operation at cryogenic temperatures, but the Thales group found that epi-side-down mounting improved thermal dissipation. The new 11.5-µm lasers, which were thermoelectrically cooled, produced an average power of 2.2 mW at 240 K and displayed lasing at temperatures up to 287 K. The team presented the results of its studies in May at CLEO 2001 in Baltimore.