Light-Sheet Skew Ray-Based Microbubble Chemical Sensor for Pb²⁺ Measurements

Area of Science:

• Optoelectronics
• Chemical Sensing
• Nanotechnology

Background:

• Lead contamination in water poses significant health risks.
• Accurate and sensitive detection methods for lead are crucial for environmental monitoring.
• Existing methods may lack sensitivity or specificity for trace lead detection.

Purpose of the Study:

• To develop and demonstrate a highly sensitive multimode fiber-based sensor for detecting trace lead in contaminated water.
• To enhance sensor performance using optical phenomena and nanomaterials.
• To achieve a detection limit significantly lower than established safety guidelines.

Main Methods:

• Utilizing a light sheet to excite skew rays within a multimode fiber for optimized light absorption.
• Incorporating an inline microbubble structure to focus skew rays and intensify the evanescent field.
• Employing gold nanoparticles functionalized with oxalic acid to amplify the evanescent field and enhance specificity for lead ions via localized surface plasmon resonance (LSPR).

Main Results:

• The proposed sensor demonstrated significantly enhanced absorption sensitivity.
• Achieved a low detection limit of 0.1305 ng/mL for lead ions.
• The detection limit is substantially lower than the World Health Organization's safety limit of 10 ng/mL.

Conclusions:

• The developed multimode fiber sensor offers a highly sensitive and specific method for detecting trace lead in water.
• The combination of optical focusing, evanescent field enhancement, and LSPR provides a robust sensing platform.
• This technology has potential applications in environmental monitoring and water quality assessment.