Fluorescent Bulk Waveguide Sensor in Porous Glass: Concept, Fabrication, and Testing

Area of Science:

• Materials Science
• Photonics
• Chemical Sensing

Background:

• Nanoporous materials offer unique environments for chemical and physical reactions.
• Optical waveguides are crucial for light manipulation in sensing applications.
• Detecting small molecules within nanoporous structures presents a significant challenge.

Purpose of the Study:

• To introduce and validate a new concept of bulk waveguides (BWGs) fabricated within porous glass (PG) for sensing applications.
• To demonstrate the capability of these BWGs to detect chemical reactions, specifically the presence of small molecules.
• To quantify the sensitivity of the developed sensing elements.

Main Methods:

• Fabrication of bulk waveguides (BWGs) inside porous glass (PG) using laser direct writing.
• Impregnation of PG plates with rhodamine 6G indicator.
• Measurement of spectral characteristics of the output signal to assess sensing performance.
• Quantification of sensitivity based on peak shift in fluorescence spectrum relative to refractive index changes.

Main Results:

• Successfully fabricated BWGs within PG using laser direct writing.
• Demonstrated the sensitivity of the BWG to ethanol molecules captured by the PG.
• Quantified the sensitivity of the peak shift in the fluorescence spectrum to the solution's refractive index as 6250 ± 150 nm/RIU.

Conclusions:

• The developed BWGs within PG serve as effective sensing elements for interrogating nanoporous materials.
• This technology shows promise for detecting chemical reactions and small molecules within nanopores.
• The high sensitivity achieved indicates potential for advanced sensing technologies in photonics and chemical detection.