Interferometer step scanning systems and methods

摘要

In some embodiments, the pathlength difference (retardation) in a step scanning infrared (IR) spectrometer interferometer is maintained under AC servomechanism (servo) control for a first period (66) following a step change (62), and under DC servo control for a second period (68) following the first period (66). Data is acquired (70) during and/or after the DC servo control period. Switching off the AC servo control prior to data acquisition allows limiting the dither-frequency noise that could otherwise affect signals of interest, particularly in fast-time-scale applications such as high-speed time-resolved spectroscopy (TSR). A mirror position control circuit controls a mirror position stepping as well as switching a mirror servo control from AC to DC.