The concept of surface impedance has been widely used in electromagnetic theory of scattering. Fo... more The concept of surface impedance has been widely used in electromagnetic theory of scattering. For a 2D scattering problem the impedance Z(x) on a surface ∑ can be defined as (1) where E║ and H║ represent the components of the electric and magnetic fields tangential to surface ∑, x is a coordinate on the surface and n^ the unit vector normal to it. If Z(x) is known, eq. (1) can be used as a boundary condition exactly equivalent to Maxwell’s, but since it is defined in terms of the fields this knowledge requires the complete solution of the scattering problem.
We present here experimental evidence of the existence of a distinct band pattern in the diffuse ... more We present here experimental evidence of the existence of a distinct band pattern in the diffuse background generated by the scattering of light on a microrough diffraction grating for both polarizations of the incident light. This sort of pattern («diffuse light bands») has been previously observed and studied for p-polarized incidence, but not for s-polarized. The band structure possesses similar features for both polarizations. The pattern for p-polarized incident light can be explained in terms of surface plasmon interaction with the random roughness existing on the grating; however, the mechanisms that generate the band structure for s-polarized incidence cannot be as easily identified
ABSTRACT Novel nanofabrication techniques are capable of producing nanoparticles with controled s... more ABSTRACT Novel nanofabrication techniques are capable of producing nanoparticles with controled structures which include small clusters, self-assembled particles, quantum dots, vesicles, etc. The non-linear optical scattering of these structures are important for applications, and can be used for their physical characterization. The second harmonic (SH) field radiated by a single small spherical particle has surface and bulk, dipolar and quadrupolar contributions of similar intensities and is strongly dependent of the local environment of the particle [1], in contrast to the linear case. In this work we calculate the nonlinear scattering by particle aggregates and we investigate the effects on the SH generation of the disorder induced field fluctuations and of the localization of light. We acknowledge the partial support from DGAPA-UNAM (grant IN110999), Conacyt (31120-E and 26651-E), CIP and UBACyT. [1] Vera L. Brudny, Bernardo S. Mendoza, and W. Luis Mochán, Phys. Rev. B 62, 11152 (2000).
Frontiers in Optics 2004/Laser Science XXII/Diffractive Optics and Micro-Optics/Optical Fabrication and Testing, 2004
ABSTRACT The propagation of evanescent pulses under the conditions of frustrated internal reflect... more ABSTRACT The propagation of evanescent pulses under the conditions of frustrated internal reflection (FTIR) may appear as superluminal and non-causal, but only if it is treated as a 1D tunneling phenomenon. When its 3D nature is fully accounted for, it may be simply explained through a subluminal causal theory.
We calculate the optical second harmonic (SH) radiation generated by small spheres made up of a h... more We calculate the optical second harmonic (SH) radiation generated by small spheres made up of a homogeneous centrosymmetric material illuminated by inhomogeneous electromagnetic fields with arbitrary transverse and longitudinal spatial variations. We obtain expressions for the hyperpolarizabilities of the particles in terms of the multipolar bulk susceptibilities and dipolar surface susceptibilities of their constitutive material. We employ the resulting response
... 5,6 OPTICS COMMUNICATIONS 1 May 1991 Spectral impurity in gratings due to surface plasmon sca... more ... 5,6 OPTICS COMMUNICATIONS 1 May 1991 Spectral impurity in gratings due to surface plasmon scattering Vera L. Brudny and Ricardo A. Depine ... Impurities are usually classified as Rowland and Lyman ghosts, satellites, grass, diffuse scatter and surface plasmon scattering. ...
An electromagnetic field forced to vary along a plane with a spatial scale d much smaller than it... more An electromagnetic field forced to vary along a plane with a spatial scale d much smaller than its free space wavelength λ decays exponentially along its normal with a decay length ∼d. This decay, similar to that of the wavefunction of tunneling electrons, has allowed the development of scanning near‐field optical microscopes (SNOMs), reminiscent of scanning tunneling and atomic force microscopes, which have been able to resolve structures in the nanometer scale. However, existing SNOMs are unable to determine the depth below the surface from which the optical signals arise due to the monotonic decay of the optical evanescent probe fields. In this paper we study the optical second harmonic generation (SHG) produced by mixing of the evanescent fields produced by a SNOM tip. We show that employing an appropriately spatially‐patterned tip, a non‐monotonic non‐linear probing field may be produced which has a maximum at a given distance beyond the tip, yielding a novel microscopy which m...
Nonlinear optical nanoscope with depth resolution. [Proceedings of SPIE 5622, 524 (2004)]. W. Lui... more Nonlinear optical nanoscope with depth resolution. [Proceedings of SPIE 5622, 524 (2004)]. W. Luis Mochan, Catalina Lopez-Bastidas, Jesus A. Maytorena, Bernardo S. Mendoza, Vera L. Brudny. Abstract. Existing optical scanning ...
Since optical second harmonic generation (SHG) is strongly supressed within centrosymmetric syste... more Since optical second harmonic generation (SHG) is strongly supressed within centrosymmetric systems but not close to their surfaces, it has been used as the basis of a powerful spectroscopy for the study of flat surfaces. Not much attention, however, has so far been paid to SHG from non planar surfaces. In this paper we develop a theory for the SHG from small spherical particles made of homogeneous isotropic media, assuming that the selvedge is thin compared to the radius, so that it is locally charcterized by the flat surface nonlinear response. The polarization induced at opposite sides of the surface do not cancel each other when the polarizing local field is inhomogeneous. Thus, a net nonlinear dipole is induced, whose contribution to the radiated field is comparable and might even dominate over the nonlinear quadrupolar radiation. We calculate the spectrum and the radiation pattern from an overlayer of particles grown over a flat surface. We identify structures in the spectrum ...
ABSTRACT Based on simple magnetic dipolium model, we calculate the surface susceptibility tensor ... more ABSTRACT Based on simple magnetic dipolium model, we calculate the surface susceptibility tensor χS that characterizes the second harmonic response from centrosymmetric magnetic material. The possibility of having enhanced or reduced magnetic moments at the surface is incorporated. Certain magnetization-induced tensor components are found to be sensitive to the surface magnetization while others depend only on its bulk value.
The concept of surface impedance has been widely used in electromagnetic theory of scattering. Fo... more The concept of surface impedance has been widely used in electromagnetic theory of scattering. For a 2D scattering problem the impedance Z(x) on a surface ∑ can be defined as (1) where E║ and H║ represent the components of the electric and magnetic fields tangential to surface ∑, x is a coordinate on the surface and n^ the unit vector normal to it. If Z(x) is known, eq. (1) can be used as a boundary condition exactly equivalent to Maxwell’s, but since it is defined in terms of the fields this knowledge requires the complete solution of the scattering problem.
We present here experimental evidence of the existence of a distinct band pattern in the diffuse ... more We present here experimental evidence of the existence of a distinct band pattern in the diffuse background generated by the scattering of light on a microrough diffraction grating for both polarizations of the incident light. This sort of pattern («diffuse light bands») has been previously observed and studied for p-polarized incidence, but not for s-polarized. The band structure possesses similar features for both polarizations. The pattern for p-polarized incident light can be explained in terms of surface plasmon interaction with the random roughness existing on the grating; however, the mechanisms that generate the band structure for s-polarized incidence cannot be as easily identified
ABSTRACT Novel nanofabrication techniques are capable of producing nanoparticles with controled s... more ABSTRACT Novel nanofabrication techniques are capable of producing nanoparticles with controled structures which include small clusters, self-assembled particles, quantum dots, vesicles, etc. The non-linear optical scattering of these structures are important for applications, and can be used for their physical characterization. The second harmonic (SH) field radiated by a single small spherical particle has surface and bulk, dipolar and quadrupolar contributions of similar intensities and is strongly dependent of the local environment of the particle [1], in contrast to the linear case. In this work we calculate the nonlinear scattering by particle aggregates and we investigate the effects on the SH generation of the disorder induced field fluctuations and of the localization of light. We acknowledge the partial support from DGAPA-UNAM (grant IN110999), Conacyt (31120-E and 26651-E), CIP and UBACyT. [1] Vera L. Brudny, Bernardo S. Mendoza, and W. Luis Mochán, Phys. Rev. B 62, 11152 (2000).
Frontiers in Optics 2004/Laser Science XXII/Diffractive Optics and Micro-Optics/Optical Fabrication and Testing, 2004
ABSTRACT The propagation of evanescent pulses under the conditions of frustrated internal reflect... more ABSTRACT The propagation of evanescent pulses under the conditions of frustrated internal reflection (FTIR) may appear as superluminal and non-causal, but only if it is treated as a 1D tunneling phenomenon. When its 3D nature is fully accounted for, it may be simply explained through a subluminal causal theory.
We calculate the optical second harmonic (SH) radiation generated by small spheres made up of a h... more We calculate the optical second harmonic (SH) radiation generated by small spheres made up of a homogeneous centrosymmetric material illuminated by inhomogeneous electromagnetic fields with arbitrary transverse and longitudinal spatial variations. We obtain expressions for the hyperpolarizabilities of the particles in terms of the multipolar bulk susceptibilities and dipolar surface susceptibilities of their constitutive material. We employ the resulting response
... 5,6 OPTICS COMMUNICATIONS 1 May 1991 Spectral impurity in gratings due to surface plasmon sca... more ... 5,6 OPTICS COMMUNICATIONS 1 May 1991 Spectral impurity in gratings due to surface plasmon scattering Vera L. Brudny and Ricardo A. Depine ... Impurities are usually classified as Rowland and Lyman ghosts, satellites, grass, diffuse scatter and surface plasmon scattering. ...
An electromagnetic field forced to vary along a plane with a spatial scale d much smaller than it... more An electromagnetic field forced to vary along a plane with a spatial scale d much smaller than its free space wavelength λ decays exponentially along its normal with a decay length ∼d. This decay, similar to that of the wavefunction of tunneling electrons, has allowed the development of scanning near‐field optical microscopes (SNOMs), reminiscent of scanning tunneling and atomic force microscopes, which have been able to resolve structures in the nanometer scale. However, existing SNOMs are unable to determine the depth below the surface from which the optical signals arise due to the monotonic decay of the optical evanescent probe fields. In this paper we study the optical second harmonic generation (SHG) produced by mixing of the evanescent fields produced by a SNOM tip. We show that employing an appropriately spatially‐patterned tip, a non‐monotonic non‐linear probing field may be produced which has a maximum at a given distance beyond the tip, yielding a novel microscopy which m...
Nonlinear optical nanoscope with depth resolution. [Proceedings of SPIE 5622, 524 (2004)]. W. Lui... more Nonlinear optical nanoscope with depth resolution. [Proceedings of SPIE 5622, 524 (2004)]. W. Luis Mochan, Catalina Lopez-Bastidas, Jesus A. Maytorena, Bernardo S. Mendoza, Vera L. Brudny. Abstract. Existing optical scanning ...
Since optical second harmonic generation (SHG) is strongly supressed within centrosymmetric syste... more Since optical second harmonic generation (SHG) is strongly supressed within centrosymmetric systems but not close to their surfaces, it has been used as the basis of a powerful spectroscopy for the study of flat surfaces. Not much attention, however, has so far been paid to SHG from non planar surfaces. In this paper we develop a theory for the SHG from small spherical particles made of homogeneous isotropic media, assuming that the selvedge is thin compared to the radius, so that it is locally charcterized by the flat surface nonlinear response. The polarization induced at opposite sides of the surface do not cancel each other when the polarizing local field is inhomogeneous. Thus, a net nonlinear dipole is induced, whose contribution to the radiated field is comparable and might even dominate over the nonlinear quadrupolar radiation. We calculate the spectrum and the radiation pattern from an overlayer of particles grown over a flat surface. We identify structures in the spectrum ...
ABSTRACT Based on simple magnetic dipolium model, we calculate the surface susceptibility tensor ... more ABSTRACT Based on simple magnetic dipolium model, we calculate the surface susceptibility tensor χS that characterizes the second harmonic response from centrosymmetric magnetic material. The possibility of having enhanced or reduced magnetic moments at the surface is incorporated. Certain magnetization-induced tensor components are found to be sensitive to the surface magnetization while others depend only on its bulk value.
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