Frequency-stabilized, three-frequency-shifted Nd:YAG laser at 372 nm for iron resonance fluorescence Doppler lidar.

Abstract

Single-mode, frequency-stabilized laser is a key component of a resonance fluorescence Doppler lidar, and the frequency of the laser emitting should be steadily locked on the resonance line of the metal atom. Here, a new Nd:YAG-based frequency-tripled source operating at 372 nm, which integrates an all-fiber-coupled seeder laser and an all-solid-state Nd:YAG laser, is developed for an iron resonance fluorescence Doppler lidar (Fe lidar). The saturation absorption spectrum of iodine near 558 nm is carried out for the first time, to our knowledge, to frequency stabilization, and the optical phase lock loop technique is used to realize the shift of seeder laser between three different frequencies. The seeder laser is injected into diode side-pumped Nd:YAG laser to generate a pulsed laser. An injection-seeded technique combined with an active cavity control technique (Ramp-fire) is applied to maintain resonance with the seeder laser and frequency stability of 864 kHz root mean square over 2 h is obtained. Laser power of about 1 W (∼16 mJ, 60 Hz) can be output after amplification and nonlinear frequency conversions. Lidar observation demonstrates that the developed source can be employed to profiling temperature and wind with high resolution and accuracy, and it can be a new choice for Fe lidar to observe atmospheric dynamics phenomena.