Andrea Chiappini

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The modal dispersion of a whispering gallery mode (WGM) resonator is a very important parameter for use in all nonlinear optics applications. In order to tailor the WGM modal dispersion of a microsphere, we have coated a silica microsphere with a high-refractive-index coating in order to study its effect on the WGM modal dispersion. We used Er(3+) ions as a(More)
Er<sup>3&#x002B;</sup>-acticated silica-hafnia glass-ceramic waveguides were fabricated by bottom-up and top-down approaches. The pros and cons of the procedures in terms of optical, spectroscopic and structural properties are reported, in particular regarding attenuation coefficient, NIR emission, and local environment for the rare-earth ions. The results(More)
In the paper the analysis of luminescence emission in the VIS spectra range of fabricated multicomponent glasses doped with rare-earth ions and PMMA doped with dyes were presented. Up-conversion emission in: germanate glass co-doped with 0.5Yb<sub>2</sub>O<sub>3</sub>/0.75Eu<sub>2</sub>O<sub>3</sub> mol% under 976 nm excitation has been investigated.(More)
Coatings of spherical optical microresonators are widely employed for different applications. Here the effect of the thickness of a homogeneous coating layer on the coupling of light from a tapered fiber to a coated microsphere has been studied. Spherical silica microresonators were coated using a 70SiO(2)- 30HfO(2) glass doped with 0.3 mol% Er(3+) ions.(More)
This paper presents optical and spectroscopic assessment, as well as morphological and structural characterization of nanoscaled photonic structures: (i) rare earth-activated oxide and fluoride glass ceramics planar waveguides; (ii) Er<sup>3+</sup>-activated micro-nano silica spheres and core-shell-like structures; (iii) rf sputtering-fabricated planar(More)
Transparent glass-ceramics, activated by luminescent species, present an important class of photonic materials because their specific optical, spectroscopic and structural properties. Several top-down and bottom-up techniques have been developed for transparent glass ceramic fabrication. Among them, laser material processing plays an important role and many(More)
In this paper, we present a short review of the activity performed in developing glass-based photonic structures on the nano and micro scale, based on the sol-gel techniques and activated by rare earth ions. Optical and spectroscopic assessment of glass ceramic waveguides is discussed. Luminescence enhancement is demonstrated. Refractive index modulation(More)
Diamond is a promising platform for sensing and quantum processing owing to the remarkable properties of the nitrogen-vacancy (NV) impurity. The electrons of the NV center, largely localized at the vacancy site, combine to form a spin triplet, which can be polarized with 532 nm laser light, even at room temperature. The NV's states are isolated from(More)
Fabrication of confined structures, where light can be confined over nano or micro scale region is fantastic challenge for nano-science based technologies. Manufacture of such structures has become possible due to the opportunity delivered by nanotechnology, which opens the way to the study of new functional artificial materials and plasmonic structures,(More)
In this paper we report on the fabrication and the characterization of colloidal systems considering complementary structures such as ordered systems (opals) and disordered ones, with the goal of highlight the properties of these systems that permit to control the light propagation through interference phenomena. In the specific we will discuss three(More)