Terahertz spectroscopy plus analysis distinguishes gasoline mixtures

Nov. 5, 2013
It is important in the petroleum industry to be able to characterize different refined-oil mixtures, which include diesel/gasoline and gasoline/gasoline (different octane grades).

More Laser Articles

Terahertz spectroscopy plus analysis distinguishes gasoline mixtures

Top Photonics News: Oil and gas and photonics

Laser spectroscopy measures motor oil consumption

It is important in the petroleum industry to be able to characterize different refined-oil mixtures, which include diesel/gasoline and gasoline/gasoline (different octane grades); one way to do this is with terahertz time-domain spectroscopy, which takes advantage of the fact that different kinds of oil have different terahertz-frequency characteristics. However, in some instances, this approach has not been precise enough: for example, when testing mixtures of 90# and 97# gasoline, the absolute error between the real and fitted value was too large (25%). Now, researchers at Tianjin University (Tianjin, China) and North Automatic Control Technology Institute (Taiyuan, China) have improved this approach by subjecting it to a multiparameter combined analysis, which reduced the absolute error in the example case to 6%.

Terahertz time-domain waveforms of the samples were acquired using a mode-locked Ti:sapphire ultrafast laser to generate electron-hole pairs that created single-cycle terahertz pulses, which were then focused by parabolic optics to a 3.5 mm spot. Changing the relative time delay between a gated pulse and the detected pulse allowed the pulse shape to be mapped out. Absorption-
coefficient spectra of the sample (which was placed in a quartz cell) were taken. The analysis was based on four parameters, two time-related and the other two absorption-related. Eleven gasoline-mixture samples were tested. The researchers believe most types of oil mixtures can be tested this way. Contact Jian Li at [email protected].

About the Author

John Wallace | Senior Technical Editor (1998-2022)

John Wallace was with Laser Focus World for nearly 25 years, retiring in late June 2022. He obtained a bachelor's degree in mechanical engineering and physics at Rutgers University and a master's in optical engineering at the University of Rochester. Before becoming an editor, John worked as an engineer at RCA, Exxon, Eastman Kodak, and GCA Corporation.

Sponsored Recommendations

Advancing Neuroscience Using High-Precision 3D Printing

March 7, 2025
Learn how Cold Spring Harbor Laboratory Used High-Precision 3D Printing to Advance Neuroscience Research using 3D Printed Optical Drives.

From Prototyping to Production: How High-Precision 3D Printing is Reinventing Electronics Manufacturing

March 7, 2025
Learn how micro 3D printing is enabling miniaturization. As products get smaller the challenge to manufacture small parts increases.

Sputtered Thin-film Coatings

Feb. 27, 2025
Optical thin-film coatings can be deposited by a variety of methods. Learn about 2 traditional methods and a deposition process called sputtering.

What are Notch Filters?

Feb. 27, 2025
Notch filters are ideal for applications that require nearly complete rejection of a laser line while passing as much non-laser light as possible.

Voice your opinion!

To join the conversation, and become an exclusive member of Laser Focus World, create an account today!