Imprinted Polymer-Based Guided Mode Resonance Grating Strain Sensors.

Area of Science:

• Optoelectronics
• Materials Science
• Nanotechnology

Background:

• Optical sensors offer advantages for strain measurement, including non-contact readout and simplified packaging.
• Guided Mode Resonance (GMR) in polymer-based gratings presents a promising avenue for developing sensitive and cost-effective strain sensors.
• Existing GMR sensors require further development for practical, large-scale applications.

Purpose of the Study:

• To develop and characterize polymer-based GMR grating sensors for optical strain sensing applications.
• To investigate the feasibility of using a soft stamp imprinting technique for GMR grating fabrication.
• To determine the absolute strain sensitivity of the fabricated GMR sensors using integrated reference sensors.

Main Methods:

• Fabrication of GMR gratings using electron beam lithography and soft stamp imprinting on polymer foils.
• Integration of GMR gratings and Bragg grating waveguides on the same sensor foil for reference measurements.
• Optical characterization of the sensor foils under applied strain to measure resonance shifts.
• Calculation of absolute strain sensitivity by comparing GMR sensor response to reference sensor data.

Main Results:

• Successful fabrication of GMR gratings on 175 μm-thick polymer foils with resonance in the 850-900 nm range.
• Demonstration of non-contact, optical readout capabilities for the GMR sensors.
• Accurate determination of the absolute strain sensitivity of the GMR gratings as 1.02 ± 0.05 pm/μϵ at 870 nm.
• Validation of the GMR sensors' performance using integrated Bragg grating waveguides as references.

Conclusions:

• Polymer-based GMR gratings are effective and sensitive optical strain sensors.
• The developed fabrication method allows for cost-effective production of GMR strain sensors.
• The GMR sensors exhibit high absolute strain sensitivity, making them suitable for various monitoring applications.