A SOLUTION TO BASE-LINE UNCERTAINTY DUE TO MCT DETECTOR NONLINEARITY IN FT-IR

High-sensitivity mercury-cadmium-teluride (MCT) detectors have generally been used in low-light experiments and where quantitation was not essential. These restrictions were commonly believed to be associated with the nonlinear response of the detectors due to intrinsic limitations of the detection process. Recent preamplifier and bias circuit designs have made significant gains in reducing and, in the case of the broad-band MCTs, virtually eliminating the nonlinear character of these detectors in typical FT-IR applications. This improvement in performance in achieved through a change in detector biasing from constant current to constant voltage.