MURRAY HILL, N. J., Oct. 20 -- Scientists at Lucent Technologies' R&D department, at Bell Labs in Murray Hill, N.J., have constructed the longest reaching semiconductor laser ever made in the photonics industry, said Lucent. The laser reaches to the far IR region and belongs to a group of quantum cascade lasers that were invented at Bell Labs for sensitive chemical analysis and diagnostic applications. Such lasers could be used to detect minute traces of pollutants in the stratosphere and in medical and combustion diagnostics, said Federico Capasso, physical research vice president at Bell Labs and a part of the research team that designed the laser. They could detect chemical concentrations of a few parts per billion.