Investigation on the differential impact of argon on the transmission performance of the atomic Faraday filter operating in the potassium yellow doublet

Abstract

In our research, we conducted a detailed analysis of the impact and causes of argon (Ar) as a buffer gas on the transmission characteristics of K-FADOF at the wavelenght of 767 nm and 770 nm. The experimental findings indicate that the incorporation of Ar has a profound effect on reshaping the spectral transmission of both the D1 and D2 lines. Notably, as the argon pressure rises, the sidebands of the D2 line are significantly subdued, while intriguingly, its central peak retains a transmission level of 40 %. Simultaneously, there is a general degradation in the transmission efficiency of the D1 line, which can be attributed to its formation mechanism mirroring that of the D2 line’s sidebands, making it susceptible to suppression by argon. The strategy of introducing argon to modulate the transmission spectrum not only provides valuable insights for the design of high-performance 770 nm K-FADOF but is also applicable to Na-FADOF, aiding in the design of high-performance filters that can effectively suppress mutual interference caused by the mere 0.6 nm wavelength difference between their yellow doublets.