Sensitivity-tunable optical sensors based on surface plasmon resonance and phase detection.

Area of Science:

• Optoelectronics
• Nanophotonics
• Sensor Technology

Background:

• Surface Plasmon Resonance (SPR) and Total Internal Reflection (TIR) are established optical sensing principles.
• Existing SPR sensors face limitations in sensitivity and tunability.
• Phase detection offers a sensitive method for analyzing optical signal changes.

Purpose of the Study:

• To enhance the sensitivity and tunability of optical sensors.
• To develop an improved sensor combining SPR and TIR principles.
• To achieve a high refractive index resolution for precise measurements.

Main Methods:

• Integration of a Surface Plasmon Resonance (SPR) device with a Total Internal Reflection (TIR) device.
• Incorporation of a quarter-wave-plate (QWP) before and after the sensor.
• Utilizing phase detection for signal analysis.
• Theoretical simulations and experimental verification of the sensor design.

Main Results:

• The novel sensor design optimizes the response curve and enhances sensitivity.
• Achieved a sensitivity-tunable optical sensor.
• Demonstrated a high resolving ability for refractive index of 1 x 10^-6 RI.
• Experimental results validated theoretical simulations.

Conclusions:

• The combined SPR-TIR approach with QWP and phase detection significantly improves optical sensor performance.
• The developed sensor offers tunable sensitivity and high refractive index resolution.
• This advancement holds potential for various applications requiring precise optical sensing.