Usually additive manufactured metal parts are showing a different mechanical behavior compared to conventionally produced parts used the same material. Apart from process-related macroscopic part imperfections (pores, surface roughness, etc.) the microstructure has a decisive influence on the mechanical properties of the materials. Thus, in order to optimize mechanical properties of metal parts...

Peak-to-average power ratio reduction in OFDM using antenna arrays (MIMO OFDM) is considered. In particular, a generalisation of selected mapping (SLM), we call it directed SLM (dSLM), is introduced. It is shown that, in contrast to schemes proposed in literature, dSLM utilises the potential offered by MIMO transmission. As a result, the complementary distribution function of the PAR exhibits a...

The hybrid technology which combines a thin layer of ferroelectric liquid crystal directly on top of a CMOS backplane has provided a hybrid technology for spatial light modulators which has already reached a mature stage of development. Devices of around 10 pixels are under construction. The use of devices in a number of systems has already been demonstrated.

Vortices of different charges are embedded in a wavefront that has quadratic phase variation, and the intensity distribution near the focal plane is studied. This method may be useful in realizing complicated beam profiles. We have experimentally demonstrated the generation of vortex arrays having integer as well as fractional topological charges that produce different intensity profiles at the...

We report experimental studies of spatial optical solitons in a nonlinear glass waveguide. Spatial solitons are self-trapped beams that propagate without diffraction. We demonstrate the formation of spatial solitons, and we investigate interactions between them. At high intensities two-photon absorption is observed to lead to the breakup of solitons. A beam propagation method is used to simulat...

We propose a method to acquire compressed measurements for efficient video reconstruction using a single-pixel camera. The method is suitable for implementation using a single-pixel detector, along with a digital micromirror device or other types of spatial light modulators. Conventional implementations of single-pixel cameras are able to spatially compress the signal, but the compressed measur...

Among the many additive manufacturing (AM) processes for metallic materials, selective laser melting (SLM) is arguably the most versatile in terms of its potential to realize complex geometries along with tailored microstructure. However, the complexity of the SLM process, and the need for predictive relation of powder and process parameters to the part properties, demands further development o...

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Building on the mathematical breakthroughs of compressive sensing (CS), we developed a 2D spectrometer system that incorporates a spatial light modulator and a single detector. For some wavelengths outside the visible spectrum, when it is too expensive to produce the large detector arrays, this scheme gives us a better solution by using only one pixel. Combining this system with the “smashed fi...

The layer-by-layer building methodology used within the powder bed process of Selective Laser Melting facilitates control over the degree of melting achieved at every layer. This control can be used to manipulate levels of porosity within each layer, effecting resultant mechanical properties. If specifically controlled, it has the potential to enable customisation of mechanical properties or de...