I3.2 - High power DFB laser diodes for gas sensing in rough environments
- SENSOR+TEST Conferences 2009
2009-05-26 - 2009-05-28
Congress Center Nürnberg
- Proceedings OPTO 2009 & IRS² 2009
- IRS² 3 - Spectroscopy
- W. Zeller, M. Legge, M. Fischer, J. Seufert, J. Koeth - nanoplus Nanosystems and Technologies GmbH, Gerbrunn, Germany
- 239 - 241
Recent years have seen a considerable increase of laser based gas and liquid sensing including fields of application in medical analytics, environmental monitoring or process control. The significant success of tunable laser diode spectroscopy (TDLS) in these areas is based particularly on its sophisticated detection limits in the range of ppm to ppb. Suitable lasers are an essential prerequisite of this technological approach. Typical devices for example used for H2O or OH sensing operate at emission wavelengths in the 2.6 - 2.7 μm range due to the very intense absorption features of both water and hydroxide in this wavelength range. Such laser diodes have typical output power levels of 1-3 mW.
In harsh environments characterized e.g. by high dust loads however, the level of particle contamination leads to substantial loss in signal due to Rayleigh-scattering of the light. In this case, TDLS application requirements include a high laser output power. Therefore it can be advisable to trade more intense absorption features for higher laser output power and use corresponding laser diodes at shorter emission wavelengths.