Continuous terahertz radiation based on an L-band 500  MHz step-stable two laser beat-frequency source.

Area of Science:

• Physics
• Spectroscopy
• Optical Engineering

Background:

• Continuous terahertz (THz) radiation sources are crucial for high-resolution spectroscopy.
• Existing THz sources often face limitations in stability, tunability, and precision.
• Maintaining polarization is essential for efficient generation and detection of THz waves.

Purpose of the Study:

• To present a novel continuous THz radiation system with enhanced stability and tunability.
• To demonstrate the system's capability for high-resolution spectroscopic analysis.
• To validate the precision frequency tuning and power stability of the generated THz waves.

Main Methods:

• Utilized an L-Band 500 MHz step-stable two laser beat-frequency source (TL-BFS) for THz generation.
• Employed an all-polarization-maintaining (PM) fiber link, including PM isolator, coupler, and EDFA.
• Excited an InGaAs photoconductive antenna (PCA) with TL-BFS to generate continuous THz radiation (0.1-2.7 THz).

Main Results:

• Achieved continuous THz radiation generation in the 0.1-2.7 THz range with stable polarization.
• Demonstrated power instability within 4% over 25 minutes and precise frequency consistency with TL-BFS intervals.
• Successfully detected a distinct absorption peak at 0.968 THz in tyrosine samples, confirming high-resolution spectroscopy capabilities.

Conclusions:

• The developed THz radiation system offers excellent tunability and stability.
• The system's high-precision 500 MHz frequency tuning is suitable for advanced spectroscopic applications.
• This technology enables high-resolution THz absorption spectroscopy, opening avenues for material analysis.