Optical remote sensing techniques are essential to analyze distant targets, enabling nonintrusive quantification or identification of substances as well as monitoring of evolutive phenomena underlining dynamical physical processes.
Various techniques like light detection and ranging (lidar) are well established and even commercially available for various applications including atmospheric studies, environmental monitoring and cultural heritage preservation, among others. Lidar have also gained significant attention for consumer devices such as cellphone cameras and head mounted displays.
“The conventional lidar techniques can typically measure only one parameter or molecular compound because they employ a single-colour laser. However, simultaneous monitoring of multiple parameters is essential for the analysis of various industrial processes like combustion,” says Abba Saleh.
In his doctoral dissertation, Saleh developed a new lidar technique that uses a single laser comprising multiple colors, also known as “white laser”, to enable simultaneous measurement of multiple molecular compounds. The molecular compounds also exhibit a characteristic temperature dependent absorption at specific colors of the laser light, which is exploited by the technique to measure temperature.
Can be utilised in reducing combustion emissions and recycling plastic
One of the most promising applications for the technique is real-time monitoring of combustion gases, which was experimentally demonstrated in an industrial power plant together with Valmet Technologies Oy.
“Fast, reliable, and real-time measurement of combustion gases are prerequisites for optimisation of the combustion process. The technique reported in my work is well suited for this task”, says Saleh.
In addition to using this new technology to monitor air composition, Saleh also extend the technique to allow measurement of multiple molecular compounds of a solid target. This opened new possibility for identification of black plastic waste. This is also experimentally demonstrated in his research work together with VTT Technical Research Center of Finland.
“I hope that the various concepts developed in my doctoral dissertation along with the experimental validation sets the framework for future technologies,” he concludes.
Abba Saleh is originally from Nigeria and currently works as a researcher in Applied Optics group at Tampere University.
Public defence on Friday 15 September
The doctoral dissertation of MSc Abba Saleh in the field of Physics titled Supercontinuum Lidar for Spectroscopic Sensing Applications will be publicly examined at the Faculty of Engineering and Natural Sciences at Tampere University at 12 o’clock on Friday 15 September 2023 at Hervanta campus, Rakennustalo, auditorium RG202 (Korkeakoulunkatu 5, Tampere). The Opponent will be Associate Professor Florian Schmidt from UMEA University. The Custos will be Professor Juha Toivonen from the Faculty of Engineering and Natural Sciences at Tampere University.
The doctoral dissertation is available online.
The public defence can be followed via remote connection.
Photo: Mika Lonka