Raman gain in 12-microm NH(3)lasers

Area of Science:

• Molecular spectroscopy
• Laser physics
• Quantum optics

Background:

• Optically pumped molecular lasers are crucial for high-resolution spectroscopy.
• Ammonia (NH3) is a molecule with significant applications in various scientific fields.
• Understanding Raman processes is key to developing new laser technologies.

Purpose of the Study:

• To report the first observation of laser emission in ammonia (NH3) on the aP(6, 2) transition.
• To investigate the underlying Raman processes in optically pumped NH3 lasers.
• To validate theoretical models with experimental measurements of small-signal gain.

Main Methods:

• Utilizing a 9-microm CO(2) laser to pump the aR(4, 2) line of NH3.
• Employing a specific pump-emission pair to minimize ac Stark shifts and population transfer.
• Measuring small-signal gain to confirm the Raman process and compare with theoretical predictions.

Main Results:

• Achieved laser emission at 12.26 microm on the NH3 aP(6, 2) transition.
• Confirmed that the observed lasing mechanism is a Raman process.
• Demonstrated good agreement between experimental measurements and theoretical calculations of small-signal gain.

Conclusions:

• The study presents the first evidence of lasing in NH3 via a Raman process.
• The chosen experimental conditions effectively isolate and study Raman scattering in optically pumped lasers.
• The findings validate the theoretical understanding of Raman processes in molecular lasers and provide a foundation for future research.