Pressure sensor based on flexible photonic crystal membrane.

Area of Science:

• Photonics
• Biomedical Engineering
• Materials Science

Background:

• Intraocular pressure (IOP) monitoring is crucial for glaucoma management.
• Existing IOP sensors face challenges with size, invasiveness, and biocompatibility.
• Development of minimally invasive, accurate pressure sensors is an ongoing need.

Purpose of the Study:

• To demonstrate a novel, flexible optical pressure sensor for potential intraocular pressure (IOP) measurement.
• To investigate the use of nanostructured Bragg gratings for remote optical pressure sensing.
• To evaluate the sensor's performance characteristics, including its limit of detection and pressure range.

Main Methods:

• Fabrication of a periodically nanostructured Bragg grating waveguide on a 50 µm polydimethylsiloxane (PDMS) membrane.
• Utilizing deformation of the photonic crystal membrane under pressure changes.
• Remote optical readout of guided mode resonance shifts observed as color changes via a camera.
• Employing crossed polarization filters to enhance resonance visibility.
• Calculating pressure from green color channel intensity changes using a calibration curve.

Main Results:

• The sensor operates based on the deformation of a nanostructured Bragg grating waveguide.
• Pressure changes induce shifts in guided mode resonances, visualized as color changes.
• The sensor demonstrated a measurable pressure range of 2000 Pa to 4000 Pa.
• A limit of detection (LOD) of 160 Pa was estimated.
• Crossed polarization filters significantly improved the visibility of optical resonances.

Conclusions:

• The developed optical pressure sensor shows promise for IOP monitoring due to its small size and biocompatibility.
• The remote optical readout mechanism allows for non-invasive pressure sensing.
• The sensor's performance, including its LOD, supports its potential as an implantable device for glaucoma management.