Two-photon lidar technique for remote sensing of atomic oxygen

Area of Science:

• Atmospheric Science
• Laser Spectroscopy
• Remote Sensing

Background:

• Atomic oxygen is a key component of the mesosphere and lower thermosphere.
• Accurate measurement of atomic oxygen is crucial for understanding atmospheric dynamics and chemistry.
• Existing remote sensing techniques can be limited by absorption interference.

Purpose of the Study:

• To propose and evaluate a novel technique for remote sensing of atomic oxygen.
• To enable probing of the mesosphere and lower thermosphere without absorption interference.
• To determine the feasibility and expected accuracy of the proposed method.

Main Methods:

• Utilizing laser excitation of a two-photon transition for atomic oxygen.
• Employing excitation at 2256 Å and detecting fluorescence at 8447 Å.
• Calculating the two-photon excitation rate and its dependence on laser parameters.

Main Results:

• The proposed technique allows probing from 200 km down to 80 km with 1-km resolution.
• Expected accuracies are better than 10% under specific laser conditions.
• The method avoids interference from absorption, a limitation of other techniques.

Conclusions:

• Two-photon laser excitation offers a promising method for remote sensing of atomic oxygen.
• The technique is suitable for atmospheric profiling from spacecraft.
• High accuracy and resolution can be achieved with optimized laser systems.