Dual homodyne detection system for measuring asymmetric spectra in the far-infrared regime

A dual homodyne detection system for measuring scattered radiation from plasmas has been fabricated. The system is operative in the far‐infrared regime, and with it the power spectral distribution of the scattered radiation in the upper and lower sidebands with respect to the frequency of the incident wave can be obtained. Theory of operation and experimental results for simulated radiation fields are given.