Sensing response characterization of a micro-holographic sensor and its kinetics simulation

Area of Science:

• Materials Science
• Optical Sensors
• Environmental Monitoring

Background:

• Existing environmental sensors often lack the required sensitivity and response speed.
• Photopolymer-based holographic gratings offer potential for high-performance sensing applications.
• Developing micro-holographic sensors can lead to more compact and efficient detection systems.

Purpose of the Study:

• To develop a photopolymer-based micro-holographic sensor for enhanced environmental factor detection.
• To characterize the response rate and sensitivity of the micro-holographic grating sensor.
• To propose a theoretical model for understanding grating formation and sensing mechanisms.

Main Methods:

• Fabrication of a micro-holographic grating using interference of counter-propagating beams in a photopolymer.
• Measurement of sensor response rate and peak wavelength shift upon exposure to relative humidity and ethanol vapor.
• Development of a diffusion model with nonlocal response to describe grating behavior and sensing.

Main Results:

• The sensor achieved a response rate of 0.171 nm/s for relative humidity and 0.03 nm/s for ethanol vapor.
• Maximum peak wavelength shifts of 51.2 nm (humidity) and 8.9 nm (ethanol) were observed within 5 minutes.
• A minimum detectable ethanol vapor concentration of 10 ppm was achieved with a sensitivity of 0.179 nm/ppm.

Conclusions:

• The developed photopolymer micro-holographic sensor demonstrates high sensitivity and rapid response for environmental monitoring.
• A theoretical diffusion model accurately describes the grating formation and sensing characteristics.
• This technology holds promise for accelerating the development of practical holographic sensing elements.