M.S.B. Darby

Design and performance of a ZnSe tetra-prism for homogeneous substrate heating using a CO2 laser for pulsed laser deposition experiments.

We report on the design and performance of a ZnSe tetra-prism for homogeneous substrate heating using a continuous wave CO(2) laser beam in pulsed laser deposition experiments. We discuss here three potential designs for homogenizing prisms and use ray-tracing modeling to compare their operation to an alternative square-tapered beam-pipe design. A square-pyramidal tetra-prism design was found to be optimal and was subjected to modeling and experimental testing to determine the influence of interference and diffraction effects on the homogeneity of the resultant intensity profile produced at the substrate surface. A heat diffusion model has been used to compare the temperature distributions produced when using various different source intensity profiles. The modeling work has revealed the importance of substrate thickness as a thermal diffuser in producing a resultant homogeneous substrate temperature distribution.

Multi-beam pulsed laser deposition for advanced thin-film optical waveguides

We discuss our progress in the use of multiple laser beams and multiple targets for the pulsed laser deposition of thin films for waveguide laser and magneto-optic applications. In contrast to the more widely used single-beam/single-target geometries, having more than one laser-produced plume can allow tuning of the material properties and complex engineering of the deposited thin films. For optical applications - the majority of the work reported here - dopants can be selectively introduced, lattice mismatch and residual strain can be compensated, which is an important factor for successful growth of thin films of ~ tens of microns thickness, and refractive index values can be adjusted for fabrication of sophisticated waveguiding structures. We discuss mixed, layered, superlattice and Bragg reflector growth, which involve out-of-plane engineering of the film structure, and in-plane engineered geometries for designs relevant to thin-film disc lasing devices. Finally we briefly discuss our most recent use of multi-plume growth for magneto-optic thin films, which involves compositional tuning of final magnetic properties.

Emerging pulsed laser deposition techniques

The use of lasers for the deposition and processing of electronic and photonic materials is becoming increasingly widespread and advances in processing technology are reducing costs and increasing throughput. Laser deposition of photonic materials and laser processing techniques can produce high quality devices with novel properties. Part one covers laser deposition and growth of materials, including pulsed laser deposition and laser-induced self-assembly of semiconductors. Part two describes laser patterning and lithography techniques, such as 3D laser lithography. Part three looks at laser treatments to manipulate properties of photonic materials for applications such as optical storage, laser components, waveguides and displays.

Pulsed laser deposition of thick multilayer garnet films for cladding-pumped planar waveguide laser devices

We report progress in the pulsed laser deposition of thick multilayer Nd/sup 3+/-doped garnet films to be used as high-numerical-aperture cladding-pumped planar waveguide laser devices.