Structural Stability of Optofluidic Nanostructures in Flow-Through Operation.

Area of Science:

• Optofluidics
• Nanophotonics
• Mechanical Engineering

Background:

• Optofluidic sensors utilize periodic arrays of subwavelength apertures for surface plasmon resonance.
• These sensors function as both optical sensors and nanofluidic devices.
• Flow-through operation can lead to pressure differences, risking structural failure of the nanoapertures.

Purpose of the Study:

• To investigate the deflection and structural stability of nanohole array-based optofluidic sensors in flow-through mode.
• To determine the safe operating pressure limits for these optofluidic devices.

Main Methods:

• Experimental analysis of sensor deflection under pressure.
• Finite element method (FEM) simulations.
• Comparison with established theoretical models.

Main Results:

• Specific sensor regions exhibit deflection and high mechanical stress under applied pressure.
• Theoretical deflection values align with experimental data when considering an effective substrate area of 450 µm.
• Safe operation is predicted up to trans-membrane pressures of 20 psi, with deflections reaching approximately 20 μm.

Conclusions:

• Periodic nanostructures in optofluidic sensors can withstand significant pressure before failure.
• Understanding deflection and stress is crucial for designing robust optofluidic devices for flow-through applications.
• The study provides critical data for optimizing the structural integrity of nanohole array sensors.