Details of Grant 

EPSRC Reference:	EP/D032989/1
Title:	Novel Laser spectroscopy for chemical and environmental sensing
Principal Investigator:	Ewart, Professor P
Other Investigators:
Researcher Co-Investigators:
Project Partners:
Department:	Oxford Physics
Organisation:	University of Oxford
Scheme:	Standard Research (Pre-FEC)
Starts:	01 August 2005	Ends:	31 March 2006	Value (£):	27,122
EPSRC Research Topic Classifications:	Analytical Science Gas & Solution Phase Reactions
EPSRC Industrial Sector Classifications:	Chemicals Environment
Related Grants:
Panel History:
Summary on Grant Application Form
Lasers emit light that can be controlled such that its colour (frequency) can be adjusted to equal the natural oscillation frequency of molecules. When the laser light has precisely the same frequency as the molecules' oscillations it is absorbed by the molecules. Every molecule has a unique set of such resonance frequencies. By measuring these frequencies we find a unique finger print of the molecule. So when we find light is absorbed at these finger print frequencies we know precisely the type of molecule that is present. This technique is called absorption spectroscopy and is a powerful method for detecting substances created in chemical reactions or emitted as polluting gases into the atmosphere. A more sophisticated type of spectroscopy creates new laser beams when the light is resonant with a molecule - this is nonlinear spectroscopy. This kind of laser spectroscopy requires high power lasers whereas absorption spectroscopy can use low power lasers. Both types of spectroscopy are being developed in this research as they can be used in different situations. It is very important to control precisely the frequency (or wavelength) of the light used to form the absorption or the nonlinear spectrum and to be able to change it over a wide range to pick up all the finger print features. The Oxford group has build an extemely powerful laser that emits very precisely defined frequencies. Normally lasers that emit only single frequencies or single mode can be tuned over only a very narrow range of frequencies. This research will develop a new way of controlling the laser so that its single frequency can be varied in a controlled way over a wide range. The new system will use a method similar to that used to keep the laser in a CD player pointed precisely at the right part of the CD as it is played. The extended tuning range of the new laser will allow very precise spectra to be obtained of molecules that absorb only infra-red light. In fact most molecules aborb only infra-red light. The aim of the research is to find a way to detect molecules created during chemical reactions such as those that occur when fuels burn in air. This will help us to understand combustion and to make it more efficient and less polluting. More efficient combustion will save energy and reduce global warming. The second part of the work will develop an entirely new way of doing spectroscopy. Instead of using a laser with a single mode i.e. emitting only a single frequency, it uses a laser with many modes at different frequencies to detect absorption over a wide spectral range. This method is called MUMAS or multi-mode absorption spectroscopy. It has the potential to give high resolution and wide spectral range at the same time and so detect finger-print spectra easily and cheaply using diode lasers. This project will investigate the technique for detecting oxygen and carbon monoxide as well as the temperature of the gas.
Key Findings
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Potential use in non-academic contexts
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Organisation Website:	http://www.ox.ac.uk