Presentation Information
[PEM15-P10]Development of a narrow-band optical filter for daytime/thermospheric observations with a Na lidar at Tromsoe (2)
*Takuya Kawahara1, Keigo Kobayashi1, Shunsuke Nomura1, Satonori Nozawa2, Norihito Saito3, Takuo T. Tsuda4, Satoshi Wada3, Toru Takahashi5 (1.Faculty of Engineering, Shinshu University, 2.ISEE, Nagoya University, 3.Center for Advanced Photonics, RIKEN, 4.University of Electro-Communications, 5.Electronic Navigation Research Institute)
Keywords:
sodium lidar,Tromsoe,daytime observation
An ultra-narrowband magneto-optical filter is being developed for the Na lidar receiver in Tromsoe to aim daytime observations under sunlit conditions. The filter consists of a heated Na cell ( > 150 C) placed in a strong magnetic field ( > 120 mT) between two crossed polarizers. A combination of magnetic field and cell temperature provides one transmission profile. A Current stage is described below.
(1) High-temperature Na atoms in the cell are chemically active. Thus, a commercially available glass-type Na cell is unstable at a high temperature of more than 150 C. An original sapphire cell is especially under development for the lidar daytime measurement.
(2) The filter was constructed using a glass-type cell for the transmission measurement. The continuous light source at 589 nm was built by the sum frequency generation technique from narrowband 1064/1319 nm DFB lasers. The magnetic field at the cell place is 245 mT. The measured transmission profiles were compared with theoretical ones at several cell temperature conditions between 160 C and 190 C.
(3) The transmission profiles vary between a magnetic field and cell temperature combinations. The Na lidar observation needs absolute and precise laser frequency control and a precise transmission profile (resolution ~1MHz) of the optical filter of the receiver. The best profile for the lidar observation is discussed using theoretical calculations.
Discussions about these topics are presented.
(1) High-temperature Na atoms in the cell are chemically active. Thus, a commercially available glass-type Na cell is unstable at a high temperature of more than 150 C. An original sapphire cell is especially under development for the lidar daytime measurement.
(2) The filter was constructed using a glass-type cell for the transmission measurement. The continuous light source at 589 nm was built by the sum frequency generation technique from narrowband 1064/1319 nm DFB lasers. The magnetic field at the cell place is 245 mT. The measured transmission profiles were compared with theoretical ones at several cell temperature conditions between 160 C and 190 C.
(3) The transmission profiles vary between a magnetic field and cell temperature combinations. The Na lidar observation needs absolute and precise laser frequency control and a precise transmission profile (resolution ~1MHz) of the optical filter of the receiver. The best profile for the lidar observation is discussed using theoretical calculations.
Discussions about these topics are presented.