The possibility of strong modification of the reflection spectrum in the photonic bandgap range of a one-dimensional photonic crystal using a dilute two-dimensional array (monolayer) of metal nanoparticles is demonstrated. It is shown that the reflection of electromagnetic wave can be completely suppressed by nanoparticles located in the surface dielectric layer. The dependence of the absorption and reflection spectra of hybrid photonic structure on the array parameters and on the shape of nanoparticles is studied. The obtained results can be used to create filters, polarizers and absorbers for predetermined frequencies in the visible and near-IR domains.
In this communication, we describe the operating principle of a polarization-sensitive dichroic filter consisting of a multilayered photonic structure with an embedded anisotropic composite layer. Our goal is to obtain two separate narrow passbands for two mutually orthogonal polarizations of light. To that effect, we propose to combine a photonic crystal structure with a two-dimensional array of spheroidal metallic nanoparticles. The former consists of two distributed Bragg reflectors surrounding a cavity layer that ensures the existence of narrow transmission peaks (defect modes) in the photonic bandgaps of the structure. The polarization sensitivity of transmittivity and reflectivity is provided by the rectangular array of spheroidal metallic nanoparticles embedded at the center of the cavity layer, in which the excitation of surface plasmon resonances depends on the relative orientations of the anisotropy axes of the nanoparticles and the polarization direction of the incoming light wave.
We show the possibility of polarization-selective amplification of a defect mode in an active photonic crystal through the excitation of surface plasmon resonance in a 2D periodic array of spheroidal metallic nanoparticles embedded in the structure. The array acts as a polarizer whose spectral characteristics depend on the shape of the nanoparticles and the periodicity of the array. The modal selectivity of the amplification is due to the strong dependence of the surface plasmon assisted light scattering by the nanoparticles on the relative orientations of their anisotropy axis and the polarization direction of the incoming light wave. We show that effective defect mode suppression, for a well-chosen polarization, can be achieved if the nanoparticles array is embedded in regions of high localization of the optical field.
Details of interaction between the blackbody radiation and neutral lithium atoms were studied in the temperature ranges
T = 100-2000 K. The rates of thermally induced decays, excitations and ionization were calculated for S-, P- and D-series
of Rydberg states in the Fues' model potential approach. The quantitative regularities for the states of the maximal
rates of blackbody-radiation-induced processes were determined. Approximation formulas were proposed for analytical
representation of the depopulation rates.
The probabilities of photoionization by the black-body radiation (BBR) were calculated for singlet and triplet S-, P-, and
D-Rydberg states of a neutral helium atom. The numerical values obtained on the basis of the Fues model potential for
states with the principal quantum number n ranging from 8 to 45 were used to derive a formula which not only reproduces
the asymptotical behavior of the ionization rate for n → ∞ but also describes exactly its maximums. The n-independent constants in this formula are determined by a third order polynomial in powers of the absolute temperature with coefficients
derived from the calculated data for the temperature range from 200 to 2000 K.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.