Details of Grant 

EPSRC Reference:	GR/S81209/01
Title:	PLATFORM: Optical Gain & Recombination in Structured Laser Materials
Principal Investigator:	Blood, Professor P
Other Investigators:	Westwood, Dr D Summers, Professor H Smowton, Professor PM
Researcher Co-Investigators:	Dr JD Thomson
Project Partners:
Department:	School of Physics and Astronomy
Organisation:	Cardiff University
Scheme:	Platform Grants (Pre-FEC)
Starts:	14 March 2004	Ends:	13 March 2008	Value (£):	448,876
EPSRC Research Topic Classifications:	Optical Devices & Subsystems
EPSRC Industrial Sector Classifications:	Electronics Pharmaceuticals and Biotechnology
Related Grants:
Panel History:
Summary on Grant Application Form
The reliable design of diode lasers depends upon accurate knowledge of the relations between optical gain, carrier density and recombination rates and fundamentally these are controlled by the distribution of electrons among the energy states of the system. Quantum dot lasers have very low threshold currents and could also offer improvements in high power and high speed lasers. However there is considerable evidence to show that the carrier distributions cannot necessarily be described by the quasi thermal Fermi-Dirac distributions usually used in laser gain calculations and that the behaviour of a specific system depends critically upon the inhomogeneous broadening of the spectra due to the size distribution of dots. This project aims to use the segmented contact technique to study gain and emission spectra of quantum dot systems, and in particular to extract the population inversion spectrum to determine the carrier distributions. The method will be applied to a variety of conventional self-assembled dots systems and an optically pumped system will be set up in order to investigate colloidal and molecular dot systems with properties which are better controlled. This will open the prospect of engineering dots systems to obtain specific characteristics, tailored to particular requirements. The method can also be used to measure optical waveguide loss and will be applied to redemitting lasers structures embodying patterned structures for reflectors and guiding, with the aim of mating improved devices for photodynamic therapy.
Key Findings
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Potential use in non-academic contexts
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Organisation Website:	http://www.cf.ac.uk