Imaging and dispersion analysis of a diffractive optical element for infrared sensors
in: Optik (2013)
Diffractive optical elements like diffractive lenses are used in infrared sensors to combine spectral ﬁltering and focusing in a single optical element. Spectral resolution, dispersion, and imaging properties depend on the geometry of the setup. These dependencies are analyzed by ray tracing for different arrangements, using the local grating period of the DOE. An optimized setup for infrared gas measurements is presented that does not rely on ﬁlters, consisting only of an emitter, a detector and the DOE. Additionally the system’s point spread function is taken into account. It is calculated by an efficient implementation of the rayleigh-sommerfeld waveﬁeld propagation technique. A prototype, based on a two-level DOE, is presented and measurements conﬁrm the simulation results.