Synthesis of rare earth hydroxide nanorods by room temperature reaction of oxide precursors with water

In this study, solid state chemical reaction of anhydrous chloride precursors with Na₂CO₃ has been used to manufacture composite powders of nanocrystalline rare earth oxide grains embedded within a matrix of NaCl. Subsequent washing of these powders with deionised water resulted in removal of the NaCl matrix and hydration of the oxide nanoparticles. In the case of Nd₂O₃ and Sm₂O₃, the hydration process yielded hydroxide nanorods. In contrast, washing of the Gd₂O₃ yielded a powder consisting of irregularly shaped nanoparticles of Gd₂O₃ and GdOOH. Analysis using high resolution transmission electron microscopy revealed that the Nd₂O₃ and Sm₂O₃ nanorods were not single crystals but were composed of crystalline subunits with a common á 0001 ñ \left\langle {0001} \right\rangle growth direction. The results obtained in this study demonstrate that rare earth hydroxide nanorods can be synthesised from oxide precursors without the need for hydrothermal processing at elevated temperature and pressure.     

Performance of conformal guided mode resonance filters

Guided mode resonance (GMR) filters are highly functional micro-optics capable of narrowband spectral filtering. GMR devices have previously been demonstrated on flat substrates using a wide range of materials and configurations. In this Letter, we apply a soft lithographic technique followed by the deposition of dielectric layers to generate GMR filters on a concave lens surface. Resonances of the resulting conformal GMR filters are experimentally measured and characterized, and the results are compared to the performance of similar GMR filters fabricated on flat surfaces.     

Scalable InP integrated wavelength selector based on binary search

We present an InP monolithically integrated wavelength selector that implements a binary search for selecting one from N modulated wavelengths. The InP chip requires only log(2)N optical filters and log(2)N optical switches. Experimental results show nanosecond reconfiguration and error-free wavelength selection of four modulated wavelengths with 2 dB of power penalty.     

Lexicodes over rings

In this paper, we consider the construction of linear lexicodes over finite chain rings by using a \(B\) -ordering over these rings and a selection criterion. As examples we give lexicodes over \(\mathbb Z _4\) and \(\mathbb F _2+u\mathbb F _2\) . It is shown that this construction produces many optimal codes over rings and also good binary codes. Some of these codes meet the Gilbert bound. We also obtain optimal self-dual codes, in particular the octacode.