| 研究実績の概要 |
The research topics on RTD was mainly investigated and it was successfully demonstrated for many imaging applications. The applicant proposed a novel way of using the RTD device as a THz transceiver based on its special oscillating property, which can greatly reduce the cost for both THz source and detector. Beside of the 2D imaging application and detection of small displacements, the proposed RTD transceiver was further introduced for fast 2D imaging system with beam scanning. However, due to the complicity of RTD device the RTD oscillating frequency cannot be controlled ideally. The range resolution was low due to the limited bandwidth of ~300MHz. In this case, the RTD transceiver cannot fully replace the conventional multiplier for high-resolution 3D imaging application.
Alternatively, we turned to the photonic imaging technique using UTC-PD instead of electronic multiplier for achieving fast data acquisition speed. A frequency-modulated continuous-wave photonic radar system was presented in the 300-GHz band. The proposed system can obtain a 6-dB bandwidth of 120 GHz for achieving a range resolution of ~1.3 mm. To obtain the desired 3D information, the array imaging technique was introduced to the proposed system for achieving 3D imaging, which was not bounded by the fixed focal distance of a focus lens. It can provide a spatial resolution of ~1.5 mm within a 3D imaging range up to ~300 mm. Notably, the data acquisition speed was reduced from second-order to ~1ms, which make it possible for realizing the real-time 3D imaging in the future.
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