Uncooled CMOS terahertz imager using a metamaterial absorber and pn diode

Area of Science:

• Terahertz (THz) imaging
• Metamaterial absorbers
• Semiconductor device physics

Background:

• Terahertz imaging offers unique capabilities for non-destructive testing and security screening.
• Existing THz imagers are often expensive, bulky, or require cryogenic cooling.
• Advancements in metamaterials and CMOS fabrication present opportunities for compact and cost-effective THz imaging solutions.

Purpose of the Study:

• To demonstrate a low-cost, uncooled terahertz imager.
• To integrate a broadband THz metamaterial absorber with a diode microbolometer sensor.
• To validate the imager's capability for stand-off imaging applications.

Main Methods:

• Fabrication of a terahertz imager using a standard 180 nm CMOS process.
• Integration of a broadband THz metamaterial absorber with a pn junction diode microbolometer sensor.
• Monolithic integration of the absorber array within the CMOS fabrication layers.
• Demonstration of imaging through transmission and reflection using the developed imager.

Main Results:

• Successful fabrication of a low-cost, uncooled terahertz imager.
• Demonstration of monolithic integration of metamaterial absorbers and sensors.
• Acquisition of transmission and reflection images of a metallic object concealed in an envelope.
• Validation of the imager's suitability for stand-off detection.

Conclusions:

• A cost-effective, uncooled terahertz imager can be realized using standard CMOS processes.
• Monolithic integration of metamaterial absorbers and microbolometer sensors is feasible and beneficial.
• The developed terahertz imager shows promise for practical stand-off imaging applications.