A system for monitoring and control of processes based on IR fibers and tunable diode lasers

In numerous cases the technique of Fiberoptic Evanescent Wave Spectroscopy (FEWS) offers great advantages over regular IR spectroscopic methods. It provides an easy way for measuring the absorption spectra of highly absorbing or highly scattering samples. With FEWS one can perform measurements in situ and in real time and this is potentially useful for measurements on biological samples or for the monitoring of chemical reactions. Several types of IR spectroscopy systems: a Fourier Transform IR(FTIR) system, tunable lead salt lasers (M) which were operated continuously (CW) and a tunable CO2 laser are discussed as FEWS system.