[P-EM15] 太陽地球系結合過程の研究基盤形成

[PEM15-P10] TromsoのNa lidarに用いる昼間観測と熱圏観測のための超狭帯域フィルタの開発(3)

*川原 琢也¹、野澤 悟徳²、斎藤 徳人³、津田 卓雄⁴、川端 哲也²、和田 智之³、高橋 透⁵ (1.信州大学工学部、2.名古屋大学宇宙地球環境研究所、3.理化学研究所光量子工学研究センター、4.電気通信大学、5.国立研究開発法人 海上・港湾・航空技術研究所 電子航法研究所)

キーワード：ナトリウムライダー、磁気光学フィルタ

An ultra-narrowband magneto-optical filter, also called a Faraday dispersive filter, is being developed for the Na LIDAR receiver in Tromsø to enable thermonspheric observations and daytime observations in sunlit conditions. The filter consists of a heated Na cell between two crossed polarizers in a strong magnetic field, producing a transmission profile.

Currently, the following stages of development are underway:
1. A new Faraday filter is being built for the new lidar receiver. Its transmission profiles are being measured at RIKEN with a high resolution of a few MHz under different cell temperatures with magnetic fields of 170 mT. The measured transmission profiles are being compared with theoretical ones for validation.
2. A new sapphire cell is being developed for LIDAR daytime measurements. Commercially available glass-type Na cells corrode at high temperatures of over 150°C due to chemically active high-temperature Na atoms in the cell.
3. A thermal stability test of the transmission profiles has been conducted, assuming long-term observation. The filter transmission during observation is required for data analysis, so the transmission needs to be measured between observations.

Discussions on these topics are presented in the talk.