Integrated optical readout using a hybrid plasmonic directional coupler in water

Area of Science:

• Photonics
• Nanotechnology
• Biosensing

Background:

• Integrated polymer optical readouts are crucial for miniaturized cantilever-based sensors in lab-on-chip systems.
• Conventional readouts using end-fire coupling have limited sensitivity in the sub-micrometer deflection range due to waveguide mode profiles.

Purpose of the Study:

• To develop an integrated optical readout with improved sensitivity for sub-micrometer cantilever deflections.
• To enhance the performance of cantilever-based sensors for liquid-state chemical and biological measurements.

Main Methods:

• Proposed an integrated optical readout utilizing a hybrid plasmon directional coupler.
• The coupler combines a short-range surface plasmon waveguide with a polymer waveguide.
• Investigated the sensitivity of coupling length and propagation loss to cantilever deflection.

Main Results:

• The hybrid plasmon directional coupler demonstrates ultra-sensitivity to cantilever deflection in the sub-micrometer range.
• Achieved improved readout sensitivity compared to conventional methods.
• Showcased extended dynamic range by integrating an array of couplers on a single microcantilever.

Conclusions:

• The proposed hybrid plasmon directional coupler offers a significant advancement for high-sensitivity cantilever-based sensors.
• Enables the design of more compact and sensitive optical waveguide-based sensors for lab-on-chip applications in aqueous environments.