A method and apparatus for remotely monitoring properties of gases and plasmas, and surface and sub-surface properties of materials, is disclosed. A laser beam is focused at a desired region within a gas, plasma, or material (e.g., solid or liquid) to be analyzed, generating an ionized sample region or a localized, enhanced free carrier region. A beam of microwave radiation is directed toward the ionized sample region or the free carrier region, and the microwave radiation is scattered. The scattered microwave radiation is received by a microwave receiver, and is processed by a microwave detection system to determine properties of the gas, plasma, or material, including surface and sub-surface properties.