The authors present a new concept for a spectrometer
adapted to low light level, high-speed operation and low spectral resolution.
It is based on a spatially modulated Mach-Zehnder Fourier transform
interferometer, with a new arrangement to record the fringes. The
interferogram is sensed by the use of a focal plane array tilted with
respect to the fringe axis. This technique allows oversampling of the
fringe pattern, which eliminates spectral aliasing that occurs with the
conventional configuration. It extends the free spectral and dynamic