Cavity Ring Down Spectroscopy (CRDS) is a highly sensitive spectroscopic technique for measurement and analysis of a sample by the scatter and absorption of light. It is widely used to identify the presence of analytes in gaseous samples down to the parts per trillion level. While CRDS is very sensitive, it is commonly hindered by the ability to rapidly extract information from complex absorption data. A new Fourier-transform based signal processing method developed at UNSW Canberra overcomes the performance limitations of existing methods affording real time analysis. This increase in processing performance increases the versatility of CRDS for a number of applications.
The technology can be used with pulsed and CW laser sources, and is specifically suited to the new quantum cascade lasers (QCL). Figure 1 shows pressure scans at two pulsed QCL wavelengths, and illustrates that that this technology can be used to monitor the gas species over a very large pressure range.
The technology can be used in conjunction with CRDS as well as well established techniques such as Fourier-Transform Infra-Red (FTIR) spectroscopy instruments to rapidly extract absorbance data from tens to hundreds of absorption features in a single spectrum. This approach can be added to existing FTIR spectrometers and does not alter the data collection process. For some spectral features, quantitative absorbance data may be obtained without the need of a background scan.
Our Fourier-transform based signal processing method affords real time analysis enabling application areas such as airport explosive detection.
The technology was developed by A/Professor Charles Harb and his team at UNSW Canberra. UNSW Innovations is responsible for the knowledge exchange and commercialisation of research and technologies developed at UNSW.
This technolgoy was recently licensed.