We previously showed that large populations (<10, 000 cm<sup>-3</sup>) of self-induced cylindrical multimode waveguides spontaneously form when an incoherent white light field suffers modulation instability in a photopolymerizable medium. By deliberately modulating the optical field and employing multiple beams, we then generated a diverse range of waveguide lattices with 1-D, 2-D and 3-D geometries. Here, we describe the potential of this technique - optochemical organization – to provide an inexpensive, single-step, room temperature route to waveguide-inscribed planar architectures, which could serve as light-collecting, steering and focusing elements.
The ability to control both spin and charge degrees of freedom in semiconductor nanostructrures is at heart of spintronic and quantum information technologies. Magnetically-doped semiconductor nanowires have emerged as a promising platform for spintronics, which warrants the exploration of their synthesis, electronic structure, and magnetic properties. Here we demonstrate the preparation of manganese-doped GaN and SnO<sub>2</sub> nanowires by chemical vapor deposition and solvothermal methods, respectively. The investigation of both systems by electron microscopy and x-ray absorption spectroscopy at ensemble and single nanowire levels indicates that manganese dopants exist in a dual oxidation state, Mn<sup>2+</sup> and Mn<sup>3+</sup>, with Mn<sup>2+</sup> being the majority species. X-ray magnetic circular dichroism studies of individual nanowires suggest ferromagnetic interactions of manganese dopants, and the nanowire orientation-dependent magnetization owing to the magnetocrystalline anisotropy. The results of these studies demonstrate quantitative determination of the dopant electronic structure at the molecular level, and allow for a prediction of the magnetic properties of diluted magnetic semiconductor nanowires based on their orientation and geometry.