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

Area of Science:

• Atmospheric Physics
• Laser Spectroscopy
• Geophysics

Background:

• Accurate temperature measurements in the mesopause region (80-115 km) are crucial for understanding atmospheric dynamics.
• Existing lidar technologies face challenges in terms of portability, stability, and operational complexity.

Purpose of the Study:

• To develop and demonstrate a high-performance, transportable sodium (Na) temperature lidar system.
• To validate the system's capability for long-term, reliable atmospheric temperature measurements.

Main Methods:

• Utilized two injection-seeded Nd:YAG pulse lasers for sum-frequency generation at 589 nm.
• Employed a narrowband laser tuned to the Doppler-broadened Na D2 spectrum for temperature profiling.
• Developed a solid-state lidar system for enhanced portability and operational stability.

Main Results:

• Achieved a laser power of 400 mW at 589 nm (40 mJ/pulse, 10 Hz repetition rate, 22 nsec FWHM pulse width).
• Successfully measured mesopause region temperatures using the Na D2 spectrum.
• Demonstrated high performance and operational capability over 3 years in Antarctica and 1 year in Japan without major issues.

Conclusions:

• The developed sodium temperature lidar is a reliable and effective tool for mesopause region temperature measurements.
• The solid-state, transportable design offers significant advantages for atmospheric research in remote locations.
• The system's long-term stable operation confirms its suitability for continuous atmospheric monitoring.