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Design, Fabrication, and Experimental Characterization of Plasmonic Photoconductive Terahertz Emitters
Published on: July 8, 2013
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Injection-seeded terahertz-wave parametric generator with timing stabilized excitation for nondestructive testing
Hiroaki Minamide1, Kouji Nawata1, Yoshikiyo Moriguchi1
1RIKEN Center for Advanced Photonics (RAP), RIKEN, Aoba-ku, Sendai 980-0845, Japan.
The Review of Scientific Instruments
|October 2, 2021
Summary
A compact terahertz-wave parametric generator (TPG) achieves high performance for nondestructive inspection. This injection-seeded TPG offers a 70 kHz repetition rate and picosecond timing jitter, enabling clear imaging of enclosed samples.
Area of Science:
- Terahertz (THz) Photonics and Spectroscopy
- Nondestructive Testing and Evaluation
- Optical Engineering and Instrumentation
Background:
- Conventional injection-seeded terahertz-wave parametric generators (is-TPGs) have limitations in measurement performance for practical applications.
- Improving pulse repetition rate, timing jitter, and output power is crucial for advancing THz-based nondestructive inspection.
- Compact and efficient THz sources are needed to broaden the applicability of terahertz technology.
Purpose of the Study:
- To develop and present a compact, high-performance injection-seeded terahertz-wave parametric generator (is-TPG).
- To enhance the measurement capabilities of the is-TPG source for nondestructive inspection applications.
- To achieve significant improvements in pulse repetition rate, timing jitter, and THz output characteristics.
Main Methods:
- Designed a novel double-pass all-solid-state optical amplifier using a laser diode (LD) master oscillator.
- Developed an achromatic optical injection system reducing conventional path length by 40%.
- Integrated the pump laser source and THz-wave generation components into a compact, two-layer enclosure.
Main Results:
- Achieved a high pulse repetition rate of up to 70 kHz and low pulse timing jitter in the tens of picoseconds.
- Demonstrated excellent THz wave performance: maximum average output power of 20 µW, spectral linewidth of ~20 GHz, and tuning range of 1.7-3.0 THz.
- Successfully performed nondestructive imaging of an enclosed human hair sample using 2.1 THz waves, obtaining a clear image with spatial resolution near the THz wavelength.
Conclusions:
- The developed compact is-TPG significantly enhances measurement performance for nondestructive inspection.
- The system's improved parameters (high repetition rate, low jitter, stable output) enable high-resolution imaging of enclosed objects.
- This advancement paves the way for broader applications of THz technology in materials science, security, and quality control.
