Passive 77 GHz millimeter-wave sensor based on optical upconversion

Area of Science:

• Sensor Technology
• Millimeter-Wave (mmW) Systems
• Optical Detection

Background:

• Millimeter-wave (mmW) sensors offer unique imaging capabilities.
• Optical upconversion provides a novel detection method for mmW signals.
• Distributed aperture systems require efficient single-element sensor characterization.

Purpose of the Study:

• To build and characterize a passive millimeter-wave (mmW) sensor.
• To evaluate the performance of optical upconversion for mmW detection.
• To assess the sensor's suitability as an element in a distributed aperture system.

Main Methods:

• A single-pixel passive millimeter-wave (mmW) sensor operating at 77 GHz was constructed.
• Raster scanning was employed to generate images.
• Optical upconversion converted mmW signals to optical signals for detection.
• System performance was analyzed, including noise equivalent temperature difference and resolution.

Main Results:

• The sensor achieved a noise equivalent temperature difference of 0.5 K with a 1-second integration time.
• A diffraction-limited resolution of approximately 8 mrad was obtained.
• Representative images demonstrating mmW phenomenology were successfully acquired.

Conclusions:

• The developed passive mmW sensor with optical upconversion is effective for imaging.
• The sensor's performance metrics are suitable for distributed aperture systems.
• The technology shows promise for various sensing and imaging applications in the mmW spectrum.