Compact millimeter-wavelength Fourier-transform spectrometer.

We have constructed a Fourier-transform spectrometer (FTS) operating between 50 GHz and 330 GHz with minimum volume (355×260×64  ) and weight (5.9 kg) while maximizing optical throughput (100   ) and optimizing the spectral resolution (4 GHz). This FTS is designed as a polarizing Martin-Puplett interferometer with unobstructed input and output in which both input polarizations undergo interference.

Polarization properties of a broadband multi-moded concentrator.

We present the design and performance of a non-imaging concentrator for use in broadband polarimetry at millimeter through submillimeter wavelengths. A rectangular geometry preserves the input polarization state as the concentrator couples f/2 incident optics to a 2π sr detector. Measurements of the co-polar and cross-polar beams in both the few-mode and highly over-moded limits agree with a simple model based on mode truncation.