Analytical theory of second harmonic generation from a nanowire with noncentrosymmetric geometry
Por:
Singla, Raksha, Luis Mochan, W.
Publicada:
14 mar 2019
Resumen:
We analytically investigate the effect of a noncentrosymmetric geometry
in the optical second harmonic (SH) generation from a nanowire made of a
centrosymmetric material, in the interior of which quadratic optical
processes are suppressed. We consider an infinite cylinder with a cross
section that is slightly deformed away from a circle and with a radius
much smaller than the wavelength. We calculate the induced linear and
nonlinear fields perturbatively in terms of the deformation parameter,
and we obtain the nonlinear dipolar and quadrupolar
hyperpolarizabilities, whose spectra we evaluate for metallic and
dielectric materials. We show that for very small deformations, the
dipolar contribution to the response competes with the quadrupolar term,
and may even be dominant. We explore the spectra of the
hyperpolarizability and identify the contributions to its structure for
metallic and dielectric nanowires. We also discuss the nature of the SH
radiation at various frequencies, and we find that it may be dominated
by the dipolar or the quadrupolar term, or that both may compete
yielding nonsymmetric radiation patterns. Our calculation may be
employed to assess, calibrate, and test numerical SH calculations.
Filiaciones:
Singla, Raksha:
Univ Nacl Autonoma Mexico, Inst Ciencias Fis, Apartado Postal 48-3, Cuernavaca 62251, Morelos, Mexico
Instituto de Ciencias Físicas, Universidad Nacional Autónoma de México, Apartado Postal 48-3, Cuernavaca, Morelos, 62251, Mexico
Luis Mochan, W.:
Univ Nacl Autonoma Mexico, Inst Ciencias Fis, Apartado Postal 48-3, Cuernavaca 62251, Morelos, Mexico
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