3:30 PM - 5:00 PM
[PEM15-P10] Development of a narrow-band optical filter for daytime/thermospheric observations with a Na lidar at Tromsoe (2)
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.