  In this work, sidebands suppression brought by buffer gas argon (Ar) in
cesium Faraday anomalous dispersion optical filter (FADOF) at 852 nm is
investigated. FADOF performances at different Ar pressures (0 torr, 1 torr, 5
torr and 10 torr) are compared, and a single-peak transmittance spectrum with
peak transmittance up to 80% is achieved at the high Ar pressure. A detailed
analysis shows that, this sidebands suppression comes from the depopulation
enhancement by the buffer gas. This result can be generalized to other FADOFs
with similar level structures such as the D2 lines of other alkali metal atoms.
