Terahertz 3D printed diffractive lens matrices for field-effect transistor detector focal plane arrays

• Published in: Optics express Vol. 24; no. 18; pp. 20119 - 20131
• Main Authors: Szkudlarek, Krzesimir, Sypek, Maciej, Cywiński, Grzegorz, Suszek, Jarosław, Zagrajek, Przemysław, Feduniewicz-Żmuda, Anna, Yahniuk, Ivan, Yatsunenko, Sergey, Nowakowska-Siwińska, Anna, Coquillat, Dominique, But, Dmytro B., Rachoń, Martyna, Węgrzyńska, Karolina, Skierbiszewski, Czesław, Knap, Wojciech
• Format: Journal Article
• Language: English
• Published: United States Optical Society of America - OSA Publishing 05.09.2016
• Subjects: General Physics; Physics
• ISSN: 1094-4087; 1094-4087
• DOI: 10.1364/OE.24.020119

We present the concept, the fabrication processes and the experimental results for materials and optics that can be used for terahertz field-effect transistor detector focal plane arrays. More specifically, we propose 3D printed arrays of a new type - diffractive multi-zone lenses of which the performance is superior to that of previously used mono-zone diffractive or refractive elements and evaluate them with GaN/AlGaN field-effect transistor terahertz detectors. Experiments performed in the 300-GHz atmospheric window show that the lens arrays offer both a good efficiency and good uniformity, and may improve the signal-to-noise ratio of the terahertz field-effect transistor detectors by more than one order of magnitude. In practice, we tested 3 × 12 lens linear arrays with printed circuit board THz detector arrays used in postal security scanners and observed significant signal-to-noise improvements. Our results clearly show that the proposed technology provides a way to produce cost-effective, reproducible, flat optics for large-size field-effect transistor THz-detector focal plane arrays.