The T-matrix method is among the most versatile, efficient, and widely used theoretical techniques for the numerically exact computation of electromagnetic scattering by homogeneous and composite particles, clusters of particles, discrete random media, and particles in the vicinity of an interface separating two half-spaces with different refractive indices. This paper presents an update to the comprehensive database of T-matrix publications compiled by us previously and includes the publications that appeared since 2007. It also lists several earlier publications not included in the original database.

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Comprehensive T-matrix reference database: A 2012-2013 update

T-matrix formulation and generalized Lorenz–Mie theories in spherical coordinates

We exploit the versatility provided by metal-dielectric composites to demonstrate controllable coherent perfect absorption (CPA) or anti-lasing in a slab of heterogeneous medium The slab is illuminated by coherent light from both sides, at the same angle of incidence and the conditions required for CPA are investigated as a function of the different system parameters Our calculations clearly elucidate the role of absorption as a necessary prerequisite for CPA We further demonstrate the controllability of the CPA frequency to the extent of having the same at two distinct frequencies even in presence of dispersion, rendering the realization of anti-lasers more flexible

Controllable coherent perfect absorption in a composite film

During the year 2008, we have been commemorating, in several places, the hundredth anniversary of the famous 1908-paper by Mie describing the interaction between an electromagnetic plane wave and a homogeneous sphere defined by its diameter d and its complex refractive index m . Due to the existence of a prior version by Lorenz, Mie's theory may also be named as Lorenz–Mie theory (LMT). The generalized Lorenz–Mie theory (GLMT) stricto sensu deals with the more general case when the illuminating wave is an arbitrary shaped beam (say: a laser beam) still interacting with a homogeneous sphere defined by its diameter d and its complex refractive index m . The name “GLMTs” is generically used to designate various variants for other particle shapes when the method of separation of variables is used. The present paper provides a review of the work accomplished in this generalized field during the last decade (the third decade). As a convenient selection criterion, only papers citing the work of the group of Rouen have been essentially used, with ISIweb of knowledge providing a database.

Generalized Lorenz-Mie theories, the third decade: A perspective

We report an experimental observation of slow light propagation in cold Rb atoms exhibiting cavity electromagnetically induced transparency (EIT). The steep slope of the atomic dispersion manifested by EIT reduces the light group velocity. The cavity filtering and feedback further contribute to the slowdown and delay of the light pulse propagation. A combination of the cavity and the EIT atomic system significantly improves the performance of the slow light propagation. A propagation time delay of ~200 ns was observed in the cavity and Rb EIT system, which is ~70 times greater than the time delay calculated for the light pulse propagation through the same Rb EIT system without the cavity.

Slow light with cavity electromagnetically induced transparency

We consider pulse propagation through a Fabry-Perot cavity with silver mirrors that contain macroscopic samples of resonant absorbers. We show that the pulse velocity can be tuned from subluminal to superluminal in a strongly coupled atom-cavity system. We delineate the effects of the interplay of cavity and absorbers. We demonstrate the saturation effects of pulse advancement with increasing mirror thickness and atomic damping.

https://www.prl.res.in/~library/Agarwal_GS_2004_4abst.pdf

Atomic absorbers for controlling pulse propagation in resonators.

We study pulse propagation through a periodic structure consisting of alternate layers of left-handed (LH) and right-handed (RH) materials. We demonstrate superluminal transit when the pulse carrier is chosen in the band gap, while the pulse tuned at the band-edge resonances exhibits subluminal velocities. The band-edge resonances, typical of the zero effective index band of the periodic structure, are shown to lead to larger group indices (as compared to usual Bragg band-edge resonances). We also demonstrate the existence of a generalized Hartman effect whereby the pulse advancement becomes insensitive to the number of periods.

https://iopscience.iop.org/article/10.1088/1464-4258/6/8/003/pdf

Subluminal and superluminal pulse propagation in a left-handed/right-handed periodic structure

We study symmetric and asymmetric stratified media with resonant absorbers to bring out the role of inversion symmetry and absorption. We show that both can be probed using the reflected fields for excitation of the structure from opposite sides. The phase asymmetry is shown to bear the signature of broken inversion symmetry in lossless systems, while losses in addition lead to the nonreciprocity in the intensity reflection coefficient. We demonstrate how reflected pulses from opposite ends can reveal both of the aspects through their shapes and delays. Moreover, we demonstrate a great flexibility in manipulating the pulse velocities mediated by the resonant atom-field interaction.

https://iopscience.iop.org/article/10.1088/1464-4266/6/12/011/pdf

Study of asymmetric multilayered structures by means of nonreciprocity in phases

We consider a system of two eccentric spheres, wherein an inclusion sphere is embedded in a larger sphere with a different refractive index. We demonstrate broken azimuthal degeneracy for non-axisymmetric illumination resulting in splittings in extinction peaks. The mode splitting and mixing effects are shown to be nonresonant, valid for all modes having sufficient quality factors. We demonstrate strong dependence of the splittings on the polarization of the incident light to the extent that one can diagnose the polarization characteristics of the whispering gallery mode. We show how a set of quantum numbers can be assigned to a given peak of the split resonances. We further investigate the field distribution in suitable coordinate planes in order to bring out the close relation between the magnetic quantum number, the polarization of the bisphere modes and that of incident light.

Broken azimuthal degeneracy with whispering gallery modes of microspheres

We consider pulse propagation through a two component composite medium (metal inclusions in a dielectric host) with or without cavity mirrors. We show that a very thin slab of such a medium, under conditions of localized plasmon resonance, can lead to significant superluminality with detectable levels of transmitted pulse. A cavity containing the heterogeneous medium is shown to lead to subluminal-to-superluminal transmission depending on the volume fraction of the metal inclusions. The predictions of phase time calculations are verified by explicit calculations of the transmitted pulse shapes. We also demonstrate the independence of the phase time on system width and the volume fraction under specific conditions.

V. S. C. Manga Rao

Papers

Atomic absorbers for controlling pulse propagation in resonators.

Subluminal and superluminal pulse propagation in a left-handed/right-handed periodic structure

Study of asymmetric multilayered structures by means of nonreciprocity in phases

Broken azimuthal degeneracy with whispering gallery modes of microspheres

Control of superluminal transit through a heterogeneous medium