A MULTIPLEXED ALL-REFLECTIVE STATIC FOURIER TRANSFORM SPECTROMETER FOR SPACE-BASED APPLICATIONS

摘要

Static Fourier transform spectrometry is a not widely used spectroscopic technique, that can be particularly attractive for space-based applications in which only one emission line is analyzed. A key advantage over traditional dispersion methodologies, at the same resolving power and throughput, is the reduced instrumental volume and weight. This is due to the fact that the resolution power is not connected to the geometrical instrumental size, as in usual dispersion spectroscopy, but to the resolving power of the dispersive elements in the optical configuration. This peculiar property, considering the growing number of micro-satellite planned missions, can be a very attractive feature. Another important characteristics is the total absence of optical or mechanical moving parts: this assures the minimization of single-point failure-risk and consequently of costs. This instrument class, in visible range, usually reaches a resolution power of the order of 10~5. Consequently, assuming a reasonable number of sampling elements in the detector, the spectral band is limited to only a few nanometers: this explains why static Fourier transform spectrometry is presently the better choice only in limited number of spatial applications. The work here presented describes a possible optical configuration useful to increase the spectral band of these instruments. The improvement is of order of five-ten in band coverage and could greatly enlarge the applicability range of these spectrometers: for example to situations in which a medium spectral range visibility is needed, or in the not so rare cases in which simultaneous high resolution monitoring of correlated emission/absorption lines is required in not contiguous regions.