"NEC has been addressing the development of a highly sensitive real-time uncooled terahertz camera and the improvement in the sensitivity of terahertz array sensors since the development of a highly sensitive bolometer-type uncooled two-dimensional terahertz array sensor in April 2008," said Dr. Naoki Oda, Executive Engineer, Radio Application, Guidance and Electro-Optics Division, NEC. "Going forward, NEC will pursue the development and production of terahertz imaging equipment using the present results and contribute to a variety of fields such as non-destructive inspection, medicine/drug development, and illegal object detection."
To improve the sensitivity, NEC expands the length of the optical cavity structure from 3 - 4 μm of the conventional value to 15 μm, which is formed between a thick metallic layer (perfect reflector) on a readout integrated circuit and thin metallic layer (THz absorber) on a pixel:
|Conventional pixel used in the existing THz camera IR/V-T0831|
|New pixel structure with a thick SiN layer to extend optical cavity length|