INP/AIGALNP QUANTUM DOT LASERS FOR 650-780NM EMISSION

Project: Research

Description

This project is about the development of a new material with nanoscale features that has properties that go beyond those of existing materials and will enable a number of applications that require light sources with properties that are not currently available. The applications include photodynamic therapy, which is a cancer treatment in which singlet (reactive) oxygen is generated at a specific location by using high power light with a photon energy sufficient to disassociate the oxygen molecule; DVD based optical storage, that requires dual wavelength sources to ensure backwards compatibility in new systems and which is necessary to support the semiconductor wafer manufacturing base within the UK; optical sensing, one form of which requires dual wavelength sources; and fluorescence lifetime studies, that are used, for example, for monitoring biological processes. We aim to demonstrate working devices that utilise this quantum dot material for these specific applications but also to investigate and demonstrate the basic material properties and the basic material and device physics to allow an even broader range of applications in the future. We will employ new strategies to grow material with the particular properties we require, we will characterise this material with a range of advanced experimental techniques, some of which we will develop particularly for this purpose, and will report on the properties of the material and the operation of working devices with new functionality.

Key findings

This project was part of a collaboration with the Universities of Sheffield and Cardiff. The overall project was about the development of a new material with nanoscale features with properties that go beyond those of existing materials to enable a number of applications that require light sources that are not currently available. The applications include photodynamic therapy, which is a cancer treatment in which singlet (reactive) oxygen is generated at a specific location by using high power light with a photon energy sufficient to disassociate the oxygen molecule; DVD based optical storage, that requires dual wavelength sources to ensure backwards compatibility in new systems and which is necessary to support the semiconductor wafer manufacturing base within the UK; optical sensing, one form of which requires dual wavelength sources; and fluorescence lifetime studies, that are used, for example, for monitoring biological processes.

The aim of this project was to demonstrate working devices that utilise indium phosphide (InP) quantum dot (QD) material and to investigate and demonstrate the basic material properties and the basic material and device physics. The objective specific to the Strathclyde part of the project was to investigate the use of InP QD active regions in vertical external cavity surface emitting lasers (VECSELs). In more detail:

1. VECSEL structures were designed to incorporate InP QD active regions.
2. VECSEL structures were grown by the project partners at Sheffield.
3. The VECSEL structures were characterised at Strathclyde and at the facilities of project partners at Cardiff University via reflectivity, photoluminescence and time-resolved photoluminescence.
4. Continuous wave operation of an InP QD VECSEL was demonstrated at Strathclyde. This laser achieved broadly tunable emission at novel wavelengths between 715 and 755nm. The laser was presented at an international conference and was reported in peer-reviewed journal Optics Express.
5. In addition to the original objectives, an InP QD VECSEL structure was used to modelock a Ti:sapphire laser. This result was reported in peer-reviewed journal IEEE Photonics Technology Letters.
StatusFinished
Effective start/end date1/10/0730/09/10

Funding

  • EPSRC (Engineering and Physical Sciences Research Council): £132,925.00

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indium phosphides
surface emitting lasers
quantum dots
cavities
lasers
wavelengths
oxygen
compatibility
therapy
light sources
manufacturing
cancer
wafers
life (durability)
fluorescence
physics
photons
continuous radiation
molecules
sapphire