Molecular nitrogen is often used as a buffer gas in cells with alkali metals due to its known ability to quench resonant fluorescence. It is widely accepted that the suppression of spontaneous emission decreases the width of coherent population trapping resonance. However, our recent results have not confirmed this positive action of molecular nitrogen within the typical range of ⁸⁷Rb concentrations and buffer gas pressures. On the opposite, we have observed the negative influence of quenching, the decrease of contrast of the coherent population trapping resonance in σ⁺–σ⁺ configuration. In this Letter, we further confirm these results implementing the Ramsey spectroscopy, and compare the characteristics of the central fringe in nitrogen and neon, and show that the latter provides a significantly better contrast-to-width ratio.

由于已知分子氮具有淬灭共振荧光的能力，因此通常在含有碱金属的细胞中用作缓冲气体。人们普遍认为，自发发射的抑制会减小相干布居捕获共振的宽度。然而，我们最近的结果尚未证实分子氮在⁸⁷ Rb 浓度和缓冲气体压力的典型范围内的这种积极作用。相反，我们观察到淬灭的负面影响，即 σ ⁺ –σ ⁺配置中相干布居捕获共振的对比度降低。在这封信中，我们进一步证实了拉姆齐光谱的这些结果，并比较了氮和氖的中心条纹特征，并表明后者提供了明显更好的对比度宽度比。