dispersion (waves)

AGREE

AGREE

Il gruppo di ricerca di Geofisica applicata della "Sapienza" Università di Roma - Dipartimento di Ingegneria Civile Edile e Ambientale - AGREE (Applied Geophysics in Rome for civil and Environmental Engineering) si occupa da decenni di sviluppi teorici e avanzamenti sperimentali delle tecniche d’indagine geofisica per applicazioni ingegneristiche, tra cui la tutela ambientale, la difesa del suolo, la valutazione dei rischi naturali ed antropici, la diagnosi di strutture, infrastrutture e del patrimonio culturale.
Le principali linee di ricerca riguardano:

Seeded intermodal four-wave mixing in a highly multimode fiber

We experimentally and theoretically investigate the process of seeded intermodal four-wave mixing in a graded-index multimode fiber, pumped in the normal dispersion regime. By using a fiber with a 100-μm core diameter, we generate a parametric sideband in the C-band (1530-1565 nm), hence allowing the use of an erbium-based laser to seed the mixing process. To limit nonlinear coupling between the pump and the seed to low-order fiber modes, the waist diameter of the pump beam is properly adjusted. We observe that the superimposed seed stimulates the generation of new spectral sidebands.

Terahertz modal analysis of a grounded liquid-crystal cell and Its application as a tunable cavity antenna

The complex mode spectra of a grounded anisotropic dielectric slab (GADS) excited by a horizontal magnetic dipole are presented in the low THz range. A liquid crystal mixture with high birefringence, low dispersive behavior and moderate losses at THz frequencies is selected as anisotropic layer. The dispersion curves of the complex modes (in both the surface-wave and leaky-wave regime) supported by the GADS are compared to those supported by the equivalent isotropic grounded dielectric slab GDS with the ordinary and the extraordinary components of the liquid crystal permittivity tensor.

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