Widely tunable compact terahertz gas lasers.

Area of Science:

• Physics
• Spectroscopy
• Laser Technology

Background:

• The terahertz (THz) region of the electromagnetic spectrum remains underutilized due to limitations in existing radiation sources.
• Developing compact, tunable, and bright THz sources is crucial for advancing scientific research and technological applications.

Purpose of the Study:

• To introduce a novel, compact, and widely frequency-tunable source of bright terahertz radiation.
• To demonstrate the potential for generating THz radiation across a broad spectral range using molecular gases.

Main Methods:

• Utilized a gas-phase molecular laser system optically pumped by a quantum cascade laser.
• Investigated rotational population inversions in molecular gases to achieve lasing.
• Identified key molecular parameters for optimizing THz laser performance.

Main Results:

• Demonstrated a widely tunable THz source with 37 lasing lines spanning 0.251 to 0.955 THz using nitrous oxide.
• Achieved narrow kilohertz linewidths for all demonstrated laser lines.
• Projected the possibility of achieving laser lines over 1 THz with milliwatt power levels from various molecular gases.

Conclusions:

• The developed quantum cascade laser-pumped molecular gas laser offers a versatile and powerful solution for THz generation.
• This approach significantly expands the accessibility and tunability of THz sources, paving the way for new applications.
• The findings suggest that numerous molecular gases can be engineered to lase across the THz spectrum with high power and tunability.