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Metallic copper Cu and bimetallic copper–silver CuAg nanoparticles (NPs) are generated by the ablation of copper bulk target in water and aqueous Ag colloidal solution, respectively. The experiments were performed using nanosecond Nd:YAG laser operating at 1064 nm. The generated NPs are characterized by UV–vis absorption spectroscopy, laser-induced breakdown spectroscopy, dynamic light scattering and scanning electron microscopy. The conducted investigations can be summarized as follows: (i) CuAg NPs colloidal solution possess the absorption in UV–vis spectral region, which can be attributed to the Cu-component; (ii) the primary bimetallic CuAg NPs have near uniform dimensions with diameter of about 15 nm, and as a rule, they are grouped into larger agglomerates without defined morphology; (iii) the obtained Cu NPs have mainly spherical form with average diameters up to 20 nm. Both types of NPs show a tendency towards the formation of large agglomerates with different morphology. Bimetallic NPs show the plasmon resonance in the vicinity of 640 nm with a good coincidence with formation of the colloidal solution of pure Cu NPs. The results also demonstrate that the core–shell structure (Ag-rich core/Cu-rich shell) is important for the formation of the bimetallic NPs, also agreeing very well with theory.

We describe a new type of photonic material inspired by a Diachrysia chrysitis moth, whose nano-structured wings exhibit a prominent golden color. This is a layered photonic structure with a large refractive index contrast, whose alternating layers are rough at the nanoscale level. Theoretical analysis shows that the scattering and interference interact to enhance the local field within the layers and increase the absorption of the material, particularly in the UV-blue part of the spectrum. Theory is experimentally verified using holographically manufactured Bragg gratings in the dichromated-pullulan (DCP). Alternating air-pullulan layers are produced and held in place by sparsely separated nano-pillars. Air voids are filled with 20-100 nm diameter spherical nanoparticles which act as scatterers. Such materials, with a high refractive index contrast and nano-scale scatterers, are important for achieving large reflectance and a broad spectrum, with scattering as an additional mechanism for spectral control.

The interaction of an Er, Yb, Cr-glass laser, operating at 1540 nm wavelength and a pulse duration of 40 ns, with Ni/Ti multilayer thin films has been studied. Five (Ni/Ti) bilayers deposited by DC ion sputtering on Si(100) wafers to a total thickness of about 180 nm were treated with laser fluences of about 6.4 and 8.8 J cm −2 . Single and multi-pulse laser irradiation was done at normal incidence in air, water and ethanol ambients. The composition and surface morphology were monitored by particle-induced x-ray emission, Rutherford backscattering spectrometry (RBS), scanning electron microscopy and profilometry. Most of the absorbed laser energy was rapidly transformed into heat, producing intensive modifications of composition and morphology on the target surface. The results show an increase in surface roughness, formation of parallel periodic surface structures, appearance of hydrodynamic features and ablation of surface material. RBS analysis revealed that laser modification induced inter-mixing between the components of individual Ni and Ti layers, with indications of the formation of NiTi intermetallic compounds. An interesting finding is the morphological changes dominant in the Si substrate, whereas the Ni/Ti multilayer structure has mainly undergone changes in the chemical composition.