Three-photon femtosecond pumped backwards lasing in argon

Area of Science:

• Atomic physics
• Laser physics
• Atmospheric science

Background:

• Backward lasing is a nonlinear optical phenomenon.
• Three-photon pumping offers a novel excitation pathway.
• Argon-based lasers have various applications.

Purpose of the Study:

• To demonstrate backwards lasing in atomic argon.
• To investigate three-photon pumping for argon excitation.
• To explore potential applications in atmospheric trace detection.

Main Methods:

• Utilized three-photon pumping with femtosecond and picosecond lasers.
• Excitation wavelength was in the vicinity of 261nm.
• Experiments were conducted in air mixtures with varying argon mole fractions (down to 10%).

Main Results:

• Successfully demonstrated backwards lasing in atomic argon.
• Achieved well-collimated, narrowband coherent emission at 1327nm.
• Confirmed lasing in low argon concentrations (10%).

Conclusions:

• Three-photon pumping is an effective method for backwards lasing in argon.
• The developed technique shows promise for standoff trace detection in the atmosphere.