Sensitive and Compact Evanescent-Waveguide Optical Detector for Sugar Sensing in Commercial Beverages.

Area of Science:

• Photonics and Sensing
• Microelectronics
• Analytical Chemistry

Background:

• Refractive index sensing is crucial for analyte concentration determination.
• Existing methods often involve complex, bulky, and expensive optical setups.
• There is a need for compact, sensitive, and cost-effective refractive index sensors.

Purpose of the Study:

• To develop a compact and highly sensitive refractive index sensor.
• To utilize microelectronics for device miniaturization and cost reduction.
• To demonstrate the sensor's capability in analyzing real-world samples, such as beverages.

Main Methods:

• Leveraging changes in optical absorption of evanescent waves caused by the sample.
• Integrating sample-light interaction and detector onto a 1 cm² glass substrate using microelectronics.
• Employing a low-noise p-i-n hydrogenated amorphous silicon junction manufactured with four UV lithographic steps.

Main Results:

• Achieved high sensitivity with values of 32, 53, and 80 pA/% for different beverages.
• Demonstrated low limits of detection (LOD) of 47, 29, and 18 ppm.
• The sensor's performance is comparable to state-of-the-art methods but with a more compact and cost-effective design.

Conclusions:

• The developed sensor offers a compact, sensitive, and low-cost solution for refractive index sensing.
• Microelectronics integration enables miniaturization and efficient manufacturing.
• The sensor is effective for analyzing analyte concentrations in commercial beverages, showing promise for various applications.