Humidity Responsive Photonic Sensor based on a Carboxymethyl Cellulose Mechanical Actuator

Area of Science:

• Materials Science
• Photonics
• Sensor Technology

Background:

• Humidity fluctuations can impact material properties and sensor performance.
• Developing responsive materials for actuation is crucial for novel sensor designs.

Purpose of the Study:

• To develop a humidity-responsive actuator using carboxymethyl cellulose (CMC).
• To integrate this actuator into a photonic-based humidity sensor utilizing a fiber Bragg grating (FBG).

Main Methods:

• Fabrication of a humidity actuator by exploiting CMC's volume changes on a glass fiber substrate.
• Coating CMC onto an FBG-containing fiber optic to create a humidity sensor.
• Characterizing the sensor's response to varying relative humidity levels.

Main Results:

• The CMC-coated FBG actuator demonstrated significant mechanical strain in response to humidity.
• A large, linear shift in Bragg resonance wavelength was observed across a relative humidity range of 5% to 40%.
• The sensor achieved a measurement uncertainty of ±2% (k=1) within this humidity range.

Conclusions:

• The developed platform provides an intuitive and simple method for humidity sensing.
• The CMC-based photonic sensor offers a linear and precise response to humidity changes.
• This technology has potential applications in environmental monitoring and humidity control systems.