The Characteristics of Ar and Cs Mixed Faraday Optical Filter Under Different Signal Powers

The characteristics of the 852 nm cesium Faraday anomalous dispersion optical filter with Ar-filled cesium cell under different signal powers are investigated. The transmittance spectra are measured by changing the input laser power from 0.05 to 10 mW (the irradiance from 12.03 to 2406.88 W/m
²
) and the buffer gas pressure from 1 to 10 torr. The spectra without the buffer gas are also measured. The results reveal the entirely different variations of the transmittance spectra for the cells with and without the buffer gas. For the cell without the buffer gas, the sidebands of the spectrum get higher and the bandwidth is broadened as the input power increases. However, for the cell with the buffer gas, the sidebands are suppressed and the bandwidth is reduced. A single-peak transmittance spectrum will be formed eventually. These phenomena are remarkable at relatively high pressures of Ar (5 and 10 torr), which may be very suitable for applications such as Faraday laser, optical frequency standard, laser frequency stabilization, and laser locking. The sidebands of the spectrum can also be used to restrict the high input laser power which may cause damage to the system.