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Record-high sensitivity compact multi-slot sub-wavelength Bragg grating refractive index sensor on SOI platform
Optics Express
|September 29, 2020
Summary
This study presents a compact, high-sensitivity refractive index (RI) sensor using a multi-slot sub-wavelength Bragg grating. It achieves a record sensitivity of 730 nm/RIU, enabling efficient RI detection in various liquids.
Area of Science:
- Photonics and Optical Sensing
- Nanotechnology
- Materials Science
Background:
- Refractive index (RI) sensors are crucial for detecting changes in liquid mediums.
- Compact and highly sensitive sensors are needed for advanced applications.
- Bragg gratings offer potential for precise optical sensing.
Purpose of the Study:
- To investigate a high-sensitivity compact multi-slot sub-wavelength Bragg grating (BG) RI sensor.
- To optimize structural parameters for enhanced sensitivity and performance.
- To experimentally demonstrate a record-high sensitivity with a compact sensor design.
Main Methods:
- Utilized 3D finite-difference time-domain (FDTD) simulations for structural optimization.
- Focused on the first side-lobe of the BG stop-band as the sensing peak.
- Fabricated the sensor using the lift-off technique on SOI platforms.
Main Results:
- Achieved a record-high sensitivity of 730 nm/RIU.
- Demonstrated sensor functionality with various liquids (water, sugar solutions, acetone, IPA).
- Developed a compact sensor with a length of 9.5 µm and 3 dB transmission loss.
Conclusions:
- The multi-slot sub-wavelength Bragg grating sensor offers excellent RI sensing capabilities.
- The optimized design and fabrication process lead to high sensitivity and compactness.
- This sensor is suitable for diverse liquid analysis applications requiring precise RI measurement.
