High-speed fiber-coupled terahertz time-domain spectroscopy system using a bias-free plasmonic source

Area of Science:

• Optics and Photonics
• Spectroscopy
• Materials Science

Background:

• Terahertz time-domain spectroscopy (THz-TDS) is a powerful technique for material characterization.
• Existing THz-TDS systems often face limitations in speed and portability.
• Development of compact, high-speed THz-TDS systems is crucial for advanced sensing applications.

Purpose of the Study:

• To demonstrate a high-speed, fiber-coupled THz-TDS system.
• To utilize a bias-free plasmonic terahertz source for improved system performance.
• To showcase the system's capability for rapid material analysis.

Main Methods:

• A compact femtosecond fiber laser oscillator powering dual-branch fiber amplifiers.
• A polarization-maintaining, fiber-coupled optical delay line for precise temporal control.
• A bias-free plasmonic terahertz source and detector integrated into a robust platform.

Main Results:

• Achieved a peak dynamic range of 81 dB and bandwidth > 3.5 THz at 3.75 Hz scan rate.
• Fiber amplifiers operated in self-similar regime, mitigating pulse distortion and dispersion.
• Demonstrated rapid quantification of pharmaceutical tablet porosity and density.

Conclusions:

• The developed THz-TDS system offers high speed and dynamic range.
• The system's compact and robust design facilitates practical sensing applications.
• This technology enables efficient characterization of material properties, including pharmaceutical formulations.