真空紫外波段存在几个可用于研究电离层物理现象的重要光谱, 其中1356 nm的夜气辉是重要的探测谱段, 通过对该波段辐射强度的探测可反演出电离层电子密度(TEC)及F2层峰值电子密度。 夜气辉发射线中, 1304 nm的发射线与1356 nm光谱间隔很近, 发射强度与1356 nm强度相当, 因此, 要实现对1356 nm夜气辉探测需要抑制1304 nm气辉辐射。 分别对05和1 mm厚的真空紫外级别的氟化钡晶体窗口透过率随温度变化特性进行研究, 结果表明, 氟化钡晶体的短波截止波长随温度的升高向长波方向偏移, 在一定温度范围内, 氟化钡晶体可以很好地抑制1304 nm辐射, 并在1356 nm波段有较高的透过率。 与国外相关文献所报道的通过加热SrF2晶体来抑制1304 nm辐射的方式相比, 利用氟化钡晶体作为短波截止滤光片, 可以将1304 nm的杂散光完全抑制, 同时可以降低仪器功耗, 对于电离层光学遥感探测有着重要的意义。

Two VUV-grade BaF2 windows with 05 mm-thick and 1 mm-thick respectively were selected to study the transmittance variety with the temperature. The results show that the cutoff wavelength of BaF2 crystals will shift towards the long wave with the increase in temperature. In a certain temperature range, BaF2 crystals can depress 130.4nm radiation well, and also has a high transmittance at 1356 nm. Compared with the reported method in which SrF2 crystals can be applied to suppress 1304 nm stray light by heating, BaF2 crystal can inhibit the 1304 nm emission line completely, and thus reduce the power consumption of the device at the same time. This indicates that BaF2 crystals can play an important role in the ionosphere optical remote sensing detection.