Sensitivity analysis of a thin-film optical waveguide biochemical sensor using evanescent field absorption

Area of Science:

• Optoelectronics
• Biochemical Sensing
• Thin-film Technology

Background:

• Accurate measurement of aqueous biochemical concentrations is crucial for environmental monitoring and medical diagnostics.
• Existing sensors often have limitations in dynamic range or flexibility for varied applications.
• Thin-film optical waveguides offer potential for miniaturized and sensitive detection systems.

Purpose of the Study:

• To propose and investigate a multichannel thin-film optical waveguide sensor for high dynamic range biochemical concentration measurements.
• To analyze the sensor's sensitivity dependence on key physical parameters like interaction length and waveguide thickness.
• To present an efficient method for determining the absorption coefficient within the sensor system.

Main Methods:

• Fabrication of a multichannel thin-film optical waveguide sensor.
• Experimental investigation of sensor sensitivity using dye solutions and varying concentrations of carboxyhemoglobins.
• Systematic analysis of the relationship between sensitivity, interaction length, and waveguide thickness.
• Development and discussion of a method for absorption coefficient determination.

Main Results:

• The sensor demonstrates a high dynamic range for measuring aqueous biochemical concentrations.
• Sensor sensitivity is inversely proportional to waveguide thickness, indicating thinner films enhance sensitivity.
• Sensitivity is directly proportional to interaction length, allowing for tunable measurement ranges.
• Variability in interaction length provides flexibility for diverse concentration measurements.

Conclusions:

• The proposed thin-film optical waveguide sensor is a flexible and effective tool for biochemical concentration determination.
• The sensor's design allows for high dynamic range measurements adaptable to different analyte concentrations.
• The findings provide a foundation for developing advanced optical sensors for various analytical applications.