Demonstrating a Filter-Free Wavelength Sensor with Double-Well Structure and Its Application

Area of Science:

• Optoelectronics
• Photonics
• Biomedical Sensing

Background:

• Optical filters are traditionally used for wavelength detection in fluorescence applications.
• Existing methods can be bulky, expensive, and limit miniaturization.
• A need exists for compact, filter-free wavelength sensing solutions in bioanalytical fields.

Purpose of the Study:

• To develop and validate a filter-free wavelength sensor with a double-well structure.
• To propose a novel current ratio-based detection method using silicon absorption.
• To demonstrate the sensor's capability for fluorescence detection and quantification.

Main Methods:

• Optimization and simulation of impurity concentration for a double-well sensor structure.
• Fabrication and experimental validation of the proposed sensor.
• Development of a wavelength detection method based on the current ratio and silicon absorption coefficient.

Main Results:

• The fabricated sensor's performance was consistent with simulation results.
• Single wavelengths from 460-800 nm were successfully detected.
• Fluorescence from ALEXA488, 594, and 680 was accurately identified and quantified.
• The current ratio method enabled quantification across a wide wavelength band.

Conclusions:

• The proposed double-well structured sensor effectively detects wavelengths without optical filters.
• The current ratio method provides a viable approach for wavelength and fluorescence quantification.
• This technology holds promise for miniaturized, filter-free wavelength detection in biofield applications, including point-of-care testing (POCT).