Trace gas spectrometry using quantum cascade lasers

This project was initially the continuation of a previous PhD students work. This changed slightly to incorporate the initial steps of development of a new system. However the main underlying focus was the absorption of infrared light by molecular gases using a still relatively new light source. This thesis will present the results of experimental work carried out during studies on the detection of gases and the nonlinear optical effects that arise from the absorption of light from a rapid frequency swept laser. A bench mounted two channel quantum cascade laser absorption spectrometer was used during experiments to observe and reduce nonlinear effects that arise from tuning the lasers during the absorption of light by several atmospherically important gases. These gases include the oxides of nitrogen (nitrous oxide, nitrogen dioxide and nitric oxide), methane and ammonia. The pulsed laser systems used as part of the spectrometer have also been put to use performing measurements on gaseous hydrocarbon combustion (methane and ethylene flames), to determine the feasibility of making measurements within the combustion zone of a jet engine and in conjunction with a continuous wave device during pump-probe experiments at the Chemistry Department of Oxford University. A portable four channel spectrometer was used at the beginning of the project to make measurements of the exhaust fumes of diesel powered vehicles. It will also cover the initial steps and tests performed in the early stages of development of a continuous wave quantum cascade laser based spectrometer for high speed detection of trace gases.

Name dc:type.qualificationname

phd

Level dc:type.qualificationlevel

doctoral-pg

Grantor dc:publisher.institution

University of Strathclyde

Year dc:date.issued

2012

Author dc:creator

• Wilson, David

DOI

10.48730/5bba-g181

Identifier

T13324

OAI identifier oai:identifier

oai:strathclyde:0k225b07h