A compact narrow-linewidth tunable UV Ti:sapphire laser developed by researchers at the Georgia Institute of Technology (Atlanta, GA) and Applied Technology Associates (Albuquerque, NM) replaces bulky, complex dye lasers or optical parametric oscillators for environmental sensing. Applications include sensing trace gases (ozone, hydrogen oxides, and nitrogen oxides, among others) using cavity-ringdown spectroscopy or laser-induced fluorescence.
The etalon-tuned laser’s 22 mm long crystal is pumped with light at 532 nm and is tunable in the fundamental through a range of 690 to 100 nm (with some changes in optics required). The output is intracavity frequency-doubled (for example, from 784 to 392 nm to sense formaldehyde), and can be externally mixed with the pump light to create shorter wavelengths (such as mixing 392 and 532 nm wavelengths to produce light at 226 nm to sense nitric oxide). During a 20-minute period, laser-power fluctuations over one-second time spans remained at just 5%-much lower than for dye lasers. An early version of this laser has already flown on NASA’s DC-8 airborne laboratory. Contact Anne Case at [email protected].