Infrared heterodyne solar radiometry.

An infrared heterodyne radiometer has sufficient sensitivity for application to high resolution spectrometric studies of the sun and the absorption of sunlight in the atmosphere. In the 10-micron region, the resolution can typically range from less than .0067/cm to .067/cm. The minimum detectable signal can approach 10 to the -24th power W/Hz. The infrared heterodyne radiometer (IHR) can also be used for atmospheric propagation studies at the emission frequencies of the CO2 laser for the examination of the feasibility of space-to-ground laser communication links.