Since Pendry's theoretical proposition of the perfect lens, extensive researches have been carried out in the field by a
number of groups and various lenses and structures have been reported. In this article, we present and discuss light
transmission in a vertical multilayered metal-dielectric structure and a metal chain array consisting of silver spheres with
different diameters. For the incident wavelength of 660 nm, light can transmit a longer distance in the vertical multilayer
structure due to low transmission loss. For the metal nanoparticle chain structure with an incident wavelength of 508 nm,
the output light intensity can be greatly enhanced by adding a small sphere to the input end and output end, respectively
as it is believed to enhance the coupling of the field into the structure and decoupling of the field from the structure,
By means of introducing defect layers into multilayer structures composed by epsilon-negative material and mu-negative
material, the free modulation of single and double localized modes in <i>zero-φ<sub>eff</sub></i> gap is realized respectively through
adjusting the thickness of different kinds of defect layers in two designed structures. In addition, the defect modes in the
<i>zero-φ<sub>eff</sub></i> gap, being distinct from those in the Bragg gap, have the property of insensitivity to incident angle and
polarization in some degree, which would be applied widely in tunable omnidirectional filters.
The Fresnel integral is the most often used numerical method for hologram reconstruction in digital holography. However, reconstructed images with this method always include different aberrations because of the neglect of the fourth- and higher-order phase terms in the calculation. The characteristics of these aberrations induced by a Fresnel integral are studied numerically and theoretically. It is found that the quality of the reconstructed image can be degraded seriously by these induced aberrations, especially for small recording distance, and the required experimental conditions of the Fresnel integral used to obtain aberration-neglectable reconstructed images are also studied with Marechal's criteria.
According to heat conduction equations and especial boundary conditions, the photothermal emission distribution of two-layer thermally uniaxial thin films has been acquired in the cylindrical coordinate system by Hankel transformation and retransformation. Applying specific parameters to two-layer thermally uniaxial thin films, the ones are discussed. The larger are the ratios of longitudinal heat conductions and transverse ones of the thin films with high thermal diffusivity, the larger are the phase changes of the photothermal signals in the thin films. Neverthless, for the thin film with low thermal diffusion, the different ratios of longitudinal heat conductions and transverse ones are potty influences on photothermal signals. And, the smaller are optical absorption coefficients, the more evident are the influences on phases because of frequency changes.