Characteristics of the S/N ratio of the beat note obtained from the frequency-mixing experiments between a CO2 and an H2O laser

Abstract

The S/N ratio of the beat note obtained from the frequency mixing between a 32 THz CO2 laser, a 10.7 THz H2O laser and a 22 GHz klystron is measured as a function of incident power of both lasers and the klystron on the W-Ni point contact diode. A maximum S/N ratio of 36 dB is obtained. It is found that the S/N ratio arises from the product of the contributions due to the incident power and the fifth coefficient of the current-voltage characteristic of the W-Ni diode. These characteristics are discussed qualitatively.