Sodium temperature lidar based on injection seeded Nd:YAG pulse lasers using a sum-frequency generation technique

Abstract

Abstract:We report on a sodium (Na) temperature lidar based on two injection seeded Nd:YAG pulse lasers using single-pass sum-frequency generation. The laser power at 589 nm is 400 mW (40 mJ per pulse at a repetition rate of 10 Hz) and the pulse width is 22 nsec FWHM. The narrowband laser tuned to the Doppler broadened Na D 2 spectrum enables us to measure the temperature of the mesopause region (80-115 km). This solid-state transportable system demonstrated high performance and capability at Syowa Station in Antarctica for 3 years and at Uji in Japan for an additional year without any major operational troubles. resonance radiation generated in single-pass sum-frequency generation with periodically poled lithium niobate," ©2011 Optical Society of America

A thermospheric Na layer event observed up to 140 km over Syowa Station (69.0°S, 39.6°E) in Antarctica

“…Comparison of signal intensities at periods during (black) and before (blue) the thermospheric Na layer event, which were obtained at two laser frequencies of (a) the Na D 2 a peak and (b) the minimum between Na D 2 a and D 2 b peaks [cf. Kawahara et al , ]. It should be noted that the background count, defined as averaged count from 160 to 200 km, are subtracted.…”

“…The Na lidar at Syowa Station [cf. Kawahara et al , , , ] was regularly operated in 2000–2002 with the two‐frequency technique [cf. She et al , ] that was able to measure neutral temperature and Na density.…”

Relationship between Na layer and CNA variations observed at Syowa, Antarctic

“…Na lidar observations were carried out, as a part of the Japanese Antarctic Research Expedition (JARE) observations, at Syowa ( 69.0 • S , 39.6 • E ) in Antarctica between 2000and 2002(cf. Kawahara et al 2002, 2011. In this laser remote sensing, laser pulses tuned to the Na D 2 line (589 nm) were transmitted vertically, and it induced Na resonance scattering in Na layers above Syowa.…”

Mesostratospheric Lidar for the Heliogeophysical Complex

“…Одним из перспективных вариантов получения зондирующего излучения с параметрами, обеспечивающими необходимую область перестройки и ширину спектра излучения, является суммирование частот Nd:YAG-лазера с длинами волн излучения 1064 и 1319 нм [Kawahara et al, 2011]. Оценки показывают, что в ночное время определение температуры с погрешностью 1-2 K на высотах от 85 до 105 км с помощью метода резонансного рассеяния в парах натрия может осуществляться при времени накопления сигнала порядка 30 мин.…”