Enhanced sensing performance from trapezoidal metallic gratings fabricated by laser interference lithography

Area of Science:

• Plasmonics
• Nanotechnology
• Sensor technology

Background:

• Nanograting-based plasmonic sensors offer real-time, label-free detection but often involve complex fabrication.
• Existing grating structures can limit practical applications due to fabrication challenges.

Purpose of the Study:

• To propose and fabricate a simplified 1D bilayer metallic grating with a trapezoidal profile for near-infrared plasmonic sensing.
• To evaluate the sensing performance of the fabricated trapezoidal grating for glucose detection.

Main Methods:

• Fabrication of a 1D bilayer metallic grating with a trapezoidal profile (633 nm period) over a 2.25 cm² area using laser interference lithography.
• Utilizing spectral interrogation and oblique incidence for enhanced sensor performance.
• Experimental validation using glucose detection to assess sensitivity and figure-of-merit.

Main Results:

• Successful fabrication of the trapezoidal nanograting structure.
• Achieved high sensitivity of up to 786 nm/RIU and a figure-of-merit of 30 for glucose detection.
• Demonstrated superior performance compared to traditional rectangular gratings, especially at oblique incidence.

Conclusions:

• The developed trapezoidal nanograting offers a cost-effective and easily fabricated platform for plasmonic sensing.
• This research advances the development of practical and high-performance sensing devices.
• The findings pave the way for broader applications of nanograting-based plasmonic sensors.