Miniaturized laser heterodyne radiometer for carbon dioxide, methane and carbon monoxide measurements in the atmospheric column

摘要

A method and apparatus for detecting trace gas concentrations in the atmosphere. An absorption signal is provided that includes collected sunlight that has undergone absorption by a trace gas. The absorption signal is mixed with laser light at a nearby frequency to the absorption signal. An amplitude of a resulting RF signal is proportional to the concentration of the trace gas.