Apr. 21, 2014
Development of a high-performance terahertz wave source and its detection technology
RIKEN No.: 06588, 07687, 07788
Inventors
Hiroaki Minamide, Tomofumi Ikari, Ruixiang Guo, Mikiko Saito, Takashi Notake and Hiromasa Ito (Tera-Photonics Team)
Background
In utilization of terahertz (THz) waves, development of a THz wave source which can deliver high performance and functions such as high output, operation at room temperature and variable frequency is strongly demanded. The inventors have been developing a high-performance THz wave techniques that can enable "variable frequency over a broad band," "high coherence" and "operation at room temperature" using nonlinear optical technology.
Fig.1: THz wave source with variable frequency utilizing nonlinear optical crystal
Summary
[Peak power/THz wave source]
In development of a desktop-sized photoinjection-type parametric THz wave source using lithium niobate as the inorganic nonlinear optical crystal, we successfully increased the output peak-to-peak value (peak power) to a high output of kilowatts (kW). This output corresponds to the output from large systems such as free electron laser.
Fig.2: kW output photoinjection-type parametric THz wave generator
[Single-crystal growth of organic nonlinear crystal and ultrawide frequency band THz wave generation]
Organic nonlinear crystals deliver high nonlinear optical coefficients and are under the spotlight as the crystals that may address wavelength conversion with high efficiency. In particular, we have proposed THz wave generation using DAST and BNA crystals and developed a method applying solution growing as a high-quality single crystal growth technique. We have been developing a source capable of instantly switching the generated frequency over the wide THz range from sub THz to several dozen THz by utilizing the well-developed lightwave technology, and succeeded in generating an ultrawide range of approximately 1 - 30THz to date.
Fig.3: Single-crystal BNA comparable to silicon quality
[THz wave detection with high sensitivity, high-speed response and room temperature operation]
We proposed a detection method which uses a high-sensitivity photodetector by converting the THz waves into light waves with application of nonlinear optical effect. High-sensitivity THz wave detection exceeding the cryogenic (4K) bolometer has been addressed. We have also developed a high-sensitivity THz wave detection technology which operates at room temperature through application of nonlinear optical technology.
Fig.4: THz wave generation detection system (left) and THz wave detection signal (right)
Merits
- Development of a desktop-sized, room temperature operation and high-output THz wave source
- Development of a high-quality, broadband THz wave source using BNA crystal
- THz wave detection with high sensitivity and room temperature operation
References
- 1.Japanese patent No.4609993
- 2.Japanese patent No.5240858
- 3.Japanese patent No.5660565