Highly versatile fiber-based optical Fabry-Pérot gas sensor

Area of Science:

• Materials Science
• Chemical Sensing
• Optical Engineering

Background:

• Fiber-based optical sensors offer advantages in remote and harsh environment sensing.
• Fabry-Pérot (FP) interferometers are sensitive optical structures for various measurements.
• Developing versatile gas sensors requires adaptable sensing materials and robust optical designs.

Purpose of the Study:

• To develop a compact, versatile, and sensitive fiber-based optical Fabry-Pérot gas sensor.
• To demonstrate the sensor's capability to utilize various polymers for gas detection.
• To evaluate the sensor's performance with different volatile organic compounds.

Main Methods:

• Fabrication of an FP cavity by sequentially depositing silver and polymer layers on a fiber endface.
• Utilizing the spectral shift of the interference pattern in response to gas analyte exposure.
• Testing sensor response with polyethylene glycol (PEG) 400 and Norland Optical Adhesive (NOA) 81 polymers.
• Analyzing sensor performance for methanol, acetone, and hexanol vapors in continuous and pulsed modes.

Main Results:

• The fiber-based FP sensor demonstrated sensitivity to different gas analytes based on the polymer used.
• Sensitivity for methanol vapor was measured as 3.5 pm/ppm for PEG 400 and 0.1 pm/ppm for NOA 81.
• Detection limits were found to be on the order of 1-10 ppm for the tested analytes.
• The sensor showed distinct responses to methanol, acetone, and hexanol, highlighting its selectivity.

Conclusions:

• The developed fiber-based FP gas sensor is versatile, allowing the use of various polymers irrespective of their refractive index.
• The sensor exhibits high sensitivity and a low detection limit for volatile organic compounds.
• This technology holds promise for sensitive and adaptable gas sensing applications.