Millimeter and Submillimeter Wave Spectroscopy

Rotational lines of several linear molecules have been measured with high precision in the region of 0.8-to 2.0-mm wavelength. The energy source for this region is a silicon crystal multiplier driven by a centimeter-wave klystron. A silicon crystal was also used as the detector. An evacuated bolometer detector was developed for the 3-mm wave region and was used to detect rotational lines down to 2.0 mm. Although its sensitivity is lower than that of the crystal detector, the bolometer will be useful for absolute power measurements in the shorter millimeter region.