基于洛伦兹线型极光的上层大气风场探测模式研究

Study of the Detection Mode of Upper Atmospheric Wind Field Based on Lorentzian Profile Aurora

从洛伦兹线型极光的干涉强度、调制度与光程差的理论公式出发,用λ/4的步进光程差即“四强度法”获得一个波长范围内的4个干涉强度值,以实现基于洛伦兹线型极光的上层大气的风速、温度、压强等物理量的探测。提出用改形萨尼亚克成像干涉仪替代迈克耳孙干涉仪实现上层大气风场,给出了基准光程差的公式,并用四面角锥棱镜镀膜技术获得4个干涉强度值来同时探测上层大气风场的模式。最后在实验室将Kr灯557.0nm调整光束到一定宽度,对称地从顶角为60°的两面镀膜角锥棱镜的顶点入射,用768pixel×576pixel的CCD照相机接收到两个光斑的成像,这两个光斑的再复制就得到镀膜四面角锥棱镜在一个周期内的4个干涉强度光斑,从而获得上层大气风场。

Based on Lorentzian profile auroral theoretical formula of interference intensity, modulation and optical path difference (OPD), measurement of upper atmospheric wind field can be achieved. Four interference intensities are obtained by four-intensity way to detect upper atmosphere wind speed, temperature and pressure based on Lorentzian profile. The modified Sagnac interferometer (MSI) has been put forward to substitute Michelson interferometer for wind field; the benchmark optical path difference (OPD) formula of MSI has been presented. The technique of coating pyramid prism (CPP) has been put forward too. By the technique of coating pyramid prism's anti-reflection coating for three faces, four intensities can been obtained through stepped optical path difference of λ/4 at the same time. A simulation test has made: when the symmetrical light of Kr 557.0 nm to the two-faces CPP's vertex of 60° angle, there are two imager speckle patterns on the CCD camera of 768×576, copying the two imager speckle patterns there are four interference intensities in a periods, so Lorentzian profile auroral upper atmospheric wind field can be achieved.