All day
Place: Instituto de Física, UNAM (México)
Luis Mochán (UNAM)
"Homogenization of multicomponent metamaterials"
Abstract:
Using techniques borrowed from QM, it is shown that the calculation of the macroscopic dielectric response of binary metamaterials, artificial systems made of small particles of an ordinary material embedded within another, may be mapped in the non-retarded regime into the calculation of the projected Green's function of an electron in a chain of atoms with only nearest neighbor interactions, and may be obtained through the evaluation of a continued fraction whose coefficients can be very efficiently computed. This technique may be generalized to multicomponent metamaterials and to systems with characteristic lengthscales comparable to the wavelength of light, for which retardation effects become important. Dispersion and dissipation can be accounted for. The resulting response depends independently on frequency and wavevector, i.e., it is non-local. As an application, the photonic band structure of a Reusch-Bouligand structure, a naturally ocurring photonic crystal consisting of a helicoidal stack of anisotropic thin layers, is computed. It is found to have band-gaps for circular polarized light of a certain helicity only. They explain the strong circularly-polarized, metallic-like reflections from the cuticle of certain insects.
Bio:
Luis Mochán obtained his PhD at the National University of México (UNAM), where he works since 1979.
He works on solid state and surface physics, optical properties of matter, and in particular, on linear and non-linear spectroscopies of surfaces and in optical properties of metamaterials. He has occasionally participated in other activities that have had some social repercusion, such as his investigation of the molecular detector used by the mexican armed forces. His science outreach activities include a kinetic art exposition that has been exhibited in half a dozen of museums besides public squares, universities and research institutes. He has received awards from the Mexican Academy of Science (AMC), the National University of México (UNAM), the Mexican Society for the Public Communication of Science and Technology (SoMeDiCyT), the Moshinsky Medal, the Tlacaélel prize, and he is a Fellow of the American Physical Society.
All day
Place: Instituto de Física, UNAM (México)
Luis Mochán (UNAM)
"Homogenization of multicomponent metamaterials"
Abstract:
Using techniques borrowed from QM, it is shown that the calculation of the macroscopic dielectric response of binary metamaterials, artificial systems made of small particles of an ordinary material embedded within another, may be mapped in the non-retarded regime into the calculation of the projected Green's function of an electron in a chain of atoms with only nearest neighbor interactions, and may be obtained through the evaluation of a continued fraction whose coefficients can be very efficiently computed. This technique may be generalized to multicomponent metamaterials and to systems with characteristic lengthscales comparable to the wavelength of light, for which retardation effects become important. Dispersion and dissipation can be accounted for. The resulting response depends independently on frequency and wavevector, i.e., it is non-local. As an application, the photonic band structure of a Reusch-Bouligand structure, a naturally ocurring photonic crystal consisting of a helicoidal stack of anisotropic thin layers, is computed. It is found to have band-gaps for circular polarized light of a certain helicity only. They explain the strong circularly-polarized, metallic-like reflections from the cuticle of certain insects.
Bio:
Luis Mochán obtained his PhD at the National University of México (UNAM), where he works since 1979.
He works on solid state and surface physics, optical properties of matter, and in particular, on linear and non-linear spectroscopies of surfaces and in optical properties of metamaterials. He has occasionally participated in other activities that have had some social repercusion, such as his investigation of the molecular detector used by the mexican armed forces. His science outreach activities include a kinetic art exposition that has been exhibited in half a dozen of museums besides public squares, universities and research institutes. He has received awards from the Mexican Academy of Science (AMC), the National University of México (UNAM), the Mexican Society for the Public Communication of Science and Technology (SoMeDiCyT), the Moshinsky Medal, the Tlacaélel prize, and he is a Fellow of the American Physical Society.