The use of optical coherence for instrumentation devoted to CMB experiments

The thesis discusses the application of the concept of optical coherence to novel instrumentation dedicated to the study of CMB. The complex degree of mutual coherence is used to describe the performances of QUBIC (Q and U Bolometric Interferometer for Cosmology, http://www.qubic.org). An adding, single baseline, interferometer prototype, working in the WR10 waveguide band, has been tested to investigate the basic properties of mm-wavelength bolometric interferometry in a mm-wave laboratory. Moreover the performances of the optical combiner of the final instrument are investigated. The correct estimator (complex degree of mutual coherence) is defined and a simulation machine in ZEMAX to test systems is implemented and tested on a suitable system. Last part of the thesis focuses on the optical design of a Martin Pupplet Fourier transform spectrometer (where the complex degree of self coherence is measured) for the SAGACE ASI mission. A double coupled spectrometer is proposed, in order to increase its sensitivity compared to existing similar instruments, where half of the power is rejected.