Terahertz surface plasmon sensor for distinguishing gasolines

Area of Science:

• Physics
• Materials Science
• Chemistry

Background:

• Gasoline octane numbers are critical for engine performance and fuel quality.
• Accurate and rapid methods for distinguishing fuel types are essential for the petroleum industry.
• Terahertz (THz) spectroscopy offers unique capabilities for material analysis due to its sensitivity to molecular vibrations and electronic properties.

Purpose of the Study:

• To develop and demonstrate a sensitive sensor for differentiating gasolines based on their octane numbers.
• To investigate the use of terahertz surface plasmon (SP) waves for fuel analysis.
• To establish a reliable method for distinguishing between 93# and 97# octane gasolines.

Main Methods:

• Fabrication of a thin metal sheet with a periodic hole array as a terahertz surface plasmon (SP) sensor.
• Experimental measurement of terahertz transmission spectra of 93# and 97# octane gasolines using the SP sensor.
• Analysis of changes in permittivity, refractive index, and absorption coefficients of gasolines interacting with the sensor's surface waves.

Main Results:

• The terahertz SP sensor exhibited high sensitivity to changes in the dielectric properties (permittivities) of the gasoline samples.
• Distinct differences in the interaction of 93# and 97# gasolines with the sensor's surface waves were observed.
• A frequency shift of 6 GHz in the transmission peaks was achieved, enabling clear distinction between the two octane numbers.

Conclusions:

• The developed terahertz surface plasmon sensor is effective and reliable for distinguishing between different gasoline octane numbers.
• The sensor's sensitivity to permittivity variations allows for accurate fuel analysis.
• This technology holds significant potential for applications in the petroleum industry, particularly in quality control and fuel authentication.