High-Sensitivity Near-Infrared Upconversion Detector Using Hybrid Plasmonic-Photonic Structure

Area of Science:

• Materials Science
• Nanotechnology
• Optical Engineering

Background:

• Near-infrared (NIR) upconversion detectors enable direct imaging by converting NIR light to visible emission, recordable by standard cameras.
• Current detectors face limitations due to weak NIR absorption and nonlinear excitation dynamics, reducing conversion efficiency and device detectivity.

Purpose of the Study:

• To develop a camera-readable NIR upconversion detector with enhanced performance.
• To overcome the limitations of traditional lanthanide-doped upconversion detectors.

Main Methods:

• Integration of a UCNPs-PDMS microarray with cascaded plasmonic (Au nanorods) and photonic (microlens array) field-modulation elements.
• Utilized nanoscale near-field amplification and light concentration to boost upconversion luminescence.

Main Results:

• Achieved over 8-fold enhancement in raw upconversion luminescence.
• Reduced noise-equivalent irradiance (NEI) from 83.98 to 0.674 mW·cm⁻².
• Increased effective optical-readout specific detectivity from 2.17 × 10³ to 2.70 × 10⁵ Jones, a 124.6-fold improvement.

Conclusions:

• The developed cascaded hybrid architecture significantly enhances NIR upconversion detector performance.
• Demonstrated stable, quantitative optical-readout monitoring for time-lapse drying, validating its sensing capabilities.
• The detector offers a promising solution for advanced NIR imaging and sensing applications.