Real‐time sampling electronics for double modulation experiments with Fourier transform infrared spectrometers

Michael J. Green, Barbara J. Barner, Robert M. Corn
1991 Review of Scientific Instruments  
A novel synchronous real-time analog sampling method for obtaining the sum and difference interferograms in double modulation Fourier transform infrared absorption experiments is described, and the application of this sampling methodology to polarization-modulation FTIR measurements of thin films at metal surfaces is demonstrated. A quadratic approximation of the b,ackground signal is used to calculate the difference interferogram. The demodulation of a test waveform with the real-time sampling
more » ... electronics reveals how the bandwidth limitations of previous double modulation experiments on FTIR interferometers that employed lock-in amplifiers have been eliminated.
doi:10.1063/1.1142462 fatcat:jtbdvm2ahzhxbl26y6lj2scnce