研究目的
To demonstrate the effectiveness of supra-THz diagonal feedhorns and QCL devices for future space-borne ultra-high-frequency Earth-observing heterodyne radiometers.
研究成果
The integration of a 3.5 THz QCL with a waveguide and a dual diagonal feedhorn structure has demonstrated a very superior QCL beam profile when compared with unmounted devices. This work represents an important step toward the development of a new Earth observation mission, LOCUS, aimed at improving our understanding of climate change.
研究不足
The lengthy scan duration and low SNR suggested that enhancement of the system sensitivity is a higher priority. Further optical alignment adjustments are required.
1：Experimental Design and Method Selection:
The QCL was integrated into a waveguide cavity with a cross-section dimension of
2：16 × 08 mm2, machined into a copper block. Two identical diagonal feedhorns were also machined into the same block at each end of the waveguide. The block was gold plated to prevent corrosion and improve thermal heat sinking. Sample Selection and Data Sources:
The QCL used is based on a GaAs/AlGaAs phonon-assisted 'hybrid' design, processed into a 1-mm-long,
3：8-μm-wide Au–Au ridge-waveguide structure. List of Experimental Equipment and Materials:
A Golay detector mounted on a two-dimensional linear scanning system was used to measure the supra-THz emission intensity.
4：Experimental Procedures and Operational Workflow:
The QCL was cooled to ～60 K in a cw mode. The detector was located approximately 70 mm away from the feedhorn apertures, and a series of discretely sampled intensity measurements were made.
5：Data Analysis Methods:
Comparison of simulated and measured far-field antenna patterns was performed.
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