Medium resolution spectrometers based on silicon Fabry-Perot for polarimetric bolometer arrays in submillimeter astronomy, concepts and instrumental performance

Following the discoveries of the Herschel space telescope and the numerous observations in the submillimeter range of the interstellar medium (ISM), we are developing two cryogenic spectrometer concepts that can be integrated on a detector focal plane to understand the evolution of the various phases of the ISM. In this talk, we present the principle and measured performance of those two multi-wavelength Fabry-Perot. The first concept is an adjustable Fabry-Perot cavity with dielectric Bragg mirrors. This prototype, equipped with a piezoelectric mechanism is used to demonstrate the concept of a scanning Bragg mirror Fabry-Perot, enabling the spectrum around a line to be finely scanned without loss.

The second concept is a stationary array of Fabry-Perot made entirely of silicon. In this spectrometer, the cavity is made of microstructured silicon. By adjusting the size of the sub-wavelength structures, we change the optical index of the cavity and therefore the transmitted wavelength.