Within the framework of recently proposed approach to view lasing in open microcavities as a linear eigenproblem for Maxwell equations with exact boundary and radiation conditions, we study correspondence between modal thresholds field overlap coefficients. Macroscopic gain is introduced into cavity material within active region via "active" imaginary part refractive index. Each eigenvalue constituted two positive numbers, namely, wavenumber threshold value gain. This yields clear insight...

We study numerically the effect of periodicity on plasmon-assisted scattering and absorption visible light by infinite finite gratings circular silver nanowires. The grating is a convenient object analysis because possibility to reduce problem one period. use well-established method partial separation variables however make an important improvement casting resulting matrix equation Fredholm second-kind type, which guarantees convergence. If wires have sub-wavelength radii, then two types...

This article reviews the nature and history of discovery high-quality natural modes existing on periodic arrays many subwavelength scatterers; such can be viewed as specific periodically structured open resonators. These grating (GMs), like any other modes, give rise to associated resonances in electromagnetic-wave scattering absorption. Their complex wavelengths are always located very close (but not exactly at) well-known Rayleigh anomalies (RAs), determined only by period angle incidence....

We study the lasing eigenvalue problems for a periodic open optical resonator made of an infinite grating circular dielectric cylinders standing in free space, E- and H-polarization modes. If possessing "negative-absorption" refractive index, such model chain quantum wires gain material under pumping. The initial-guess values frequencies are provided by plane-wave scattering problems. demonstrate new effect: existence specific eigenmodes that have low threshold even if optically very thin.

This paper considers the scattering of an H-polarized plane wave by a freestanding periodic grating that contains two circular cylinders on each period, one made silver and other dielectric. If such is deeply subwavelength wires, reflection transmission coefficients demonstrate both plasmon resonances. To clarify them, we also discuss similar gratings either or dielectric wires only. However, main attention paid to associated lasing eigenvalue problem for pumped become quantum i.e., obtain...

We study the scattering of H-polarized plane wave by a freestanding periodic grating that contains two circular cylinders on single period, one made silver and another dielectric. The reflection transmission coefficients for such demonstrate several types resonances including plasmons resonances. Besides, we analyze associated eigenvalue problem where dielectric are so-called quantum wires, i.e. have "negative-absorption" or "active" refractive index. comparison eigensolutions modes active...

By the method of analytical regularization (MAR) we understand a family techniques casting electromagnetic boundary-value problems to Fredholm second-kind infinite- matrix equations, with or without intermediate stage second kind integral equation (IE). This approach possesses many merits however is rarely used in computational optics and photonics. In optical, infrared THz ranges, perfect electrical conductor (PEC) condition cannot be approximate even noble-metal scatterers. Therefore for...

An infinite dielectric wire grating in free space is known to possess very high-Q resonances at the frequencies close Rayleigh anomalies.Still a practical implementation of such resonator may require its embedding slab.In this paper, it shown that can bring additional improvement Q-factors.A slab with symmetrically embedded dielectric-wire investigated under normal incidence plane waves.Accurate numerical solutions are derived for E-and H-polarization cases.Associated eigenvalue problems...

Periodic structures possess a specific feature, there is set of high quality resonances near to the wavelength equal grating period and their Q-factors rise higher if becomes sparser. Making from silver elements brings other - surface-plasmon ones appearing in visible-light band. We investigate interaction between plasmon scattering absorption by infinite gratings circular cylinders thin strips, for E H-polarization cases.

In this paper, we study the scattering of H-polarized plane wave by an infinite periodic chain silver circular cylinders standing in free space. The problem is reduced to a matrix equation with favourable features using method partial separation variables. visible-light band, demonstrate interesting interaction two types resonances: localized surface plasmons nanosize and specific grating-type resonance near wavelength equal period.

In this paper, we study the scattering and eigenvalue problems for a periodic open optical resonator that is an infinite chain of active circular cylindrical quantum wires standing in free space. The problem solved by method partial separation variables. differs from first one absence incident field presence ldquoactive propertiesrdquo cylinders yields frequencies thresholds lasing.

Widely used in photonics vertical cavity surface emitting lasers (VCSEL) commonly have quantum wells as active regions. Besides many advantages of that model we propose enhancing its properties by replacing a well with periodically structured wires. Thus the specific high Q-factor grating resonances consisting placed circular cylinders [1,2] can be combined those VCSEL-type resonator. In latter device, two distributed Bragg reflectors (DBR) sandwiching middle forge high-intensity field...

Scattering of a plane wave from silver nanowire grating embedded into dielectric slab is investigated using Maxwellian formalism, to determine and distinguish effects caused by the structure periodicity presence wires which entail plasmon resonances. Comparison two polarizations provided. Common use gives an opportunity maintain effectiveness resonance while variation refractive index allows managing wavelength resonance.

Scattering of a normally incident plane wave by dielectric slab with air-filled periodic inclusions circular cylinder form is investigated. Comparison the related homogeneous problem shows presence modes associated inclusions. The corresponding resonances are sharp. Lasing threshold and real-valued lasing frequency then sought introducing negative imaginary part into refractive index to develop laser eigenvalue (LEP). dependencies on geometrical parameters found, indicate that have high efficiency.

The electromagnetic properties of a circular silver nanowire grating placed over dielectric slab are investigated using the Maxwell formalism. scattering analyzed for normally incident H-polarized plane wave. lasing studied same configuration however refractive index is assumed having negative imaginary part. modes compared in terms thresholds.

Periodic wire grating in free space has very high-Q resonances at the frequencies close to Rayleigh anomalies. We discuss a further enhancement of that effect by sandwiching between two distributed Bragg reflectors (DBRs).

One of fundamental problems electro-magnetics is the scattering a plane wave from grating infinite circular dielectric cylinders (wires). Lord Rayleigh was apparently one first researchers who formulated it in XIX century. We consider associated lasing eigenvalue problem and focus our attention on asymptotic approximations eigenvalues for large values ratio period to wire radius. Classification modes located near anomalies given.

Although still underestimated in computational optics and photonics, the conversion of electromagnetic field problems to Fredholm second kind integral equations (IEs), also called analytical regularization, finally second-kind infinite-matrix has many remarkable merits. We discuss them at background specific features material properties metals dielectrics optical range.

The electromagnetic properties of a silver nanowire grating embedded into dielectric slab are investigated, using Maxwellian formalism, to determine and distinguish effects caused by the structure periodicity presence wires which entail plasmon resonances. interaction these two gives an opportunity control qualitative characteristics resonance while variation refractive index allows managing its wavelength.

This paper reviews the history of discovery and study nature high-quality natural modes existing on periodic arrays sub-wavelength scatterers as specific periodically structured open resonators. Here, can be finite infinite, their elements dielectric metallic. These grating (G-modes), like any other modes, are "parents" corresponding resonances in electromagnetic-wave scattering absorption. In cross-sections, they usually observed Fano-shape (double-extremum) resonances, while absorption...

An infinite grating of identical dielectric or metal cylinders strips illuminated by a plane wave has high-quality optical resonances near the Rayleigh anomalies [1-16]. These are present for any periodic 2-D structures and have striking properties as their Q-factors increase if period becomes larger. Besides, in such resonance domain high-intensity scattered field occupies very wide along grating. In this paper we investigate configuration where slab an air holes inside it. This structure...