Dyadic Green’s Function for Multilayered Planar, Cylindrical, and Spherical Structures with Impedance Boundary Condition

The integral equation (IE) method is one of the efficient approaches for solving electromagnetic problems, where dyadic Green’s function (DGF) plays an important role as the Kernel of the integrals. In general, a layered medium with planar, cylindrical, or spherical geometry can be used to model different biomedical media such as human skin, body, or head. Therefore, in this chapter, different approaches for the derivation of Green’s function for these structures will be introduced. Due to the recent great interest in two-dimensional (2D) materials, the chapter will also discuss the generalization of the technique to the same structures with interfaces made of isotropic and anisotropic surface impedances. To this end, general formulas for the dyadic Green’s function of the aforementioned structures are extracted based on the scattering superposition method by considering field and source points in the arbitrary locations. Apparently, by setting the surface conductivity of the interfaces equal to zero, the formulations will turn into the associated problem with dielectric boundaries. This section will also aid in the design of various biomedical devices such as sensors, cloaks, and spectrometers, with improved functionality. Finally, the Purcell factor of a dipole emitter in the presence of the layered structures will be discussed as another biomedical application of the formulation.

Purcell enhancement of fluorescence from silicon-vacancy color centers in Mie-resonant luminescent diamond particles

Over the past two decades, nanosized diamond particles with various luminescent defects have found numerous applications in many areas from quantum technologies to medical science. The size and shape of diamond particles can affect drastically the luminescence of embedded color centers. Here we study diamond particles of 250–450 nm in size containing silicon-vacancy (SiV) centers. Using dark-field scattering spectroscopy, we found that fundamental Mie resonances are excited in the spectral range of interest. We then measured the fluorescence saturation curves under continuous excitation to estimate the effects of the excitation and Purcell factor enhancement on the luminescent properties of the studied particles. The results show that the saturation excitation intensity differs by several times for particles of different sizes which is well explained by the numerical model that takes into account both the Parcell factor enhancement and resonant excitation.

Switchable Purcell enhancement of photoluminescence by GST film

In the present paper perovskite radiation enhancement on crystalline GST film compared to amorphous one has been studied. The photonic local density of states has been calculated by angular spectrum representation of the dyadic Green’s function. The Purcell factor has been calculated for perovskite luminescent on both amorphous and crystalline GST film. Almost 80% enhancement has been observed at wavelength 950 nm for system with perovskite thickness 25 nm, GST thickness 110 nm.

Design of electrically driven single-photon source based on intra-cavity contacted microcavity with oxide-confined optical apertures emitting at 1.3 μm

We propose a hybrid microcavity design of a 1.3 μm range electrically driven single-photon source (SPS) consisting of two high-contrast dielectric distributed Bragg reflectors which surround a 3λ-thick semiconductor cavity with two intra-cavity contact layers and four 40-nm-thick oxide-confined apertures. According to 3D finite-difference time-domain modelling, the overall photon-extraction efficiency of ~74% and the Purcell factor of ~13 can be obtained by properly adjusting the position of oxide-confined apertures relative to the electric field of the fundamental optical mode. The studied SPS design also demonstrates a coupling efficiency of up to 13% within numerical aperture 0.12 in contrast to ~5% reached for a conventional semiconductor micropillar.

Dielectric nanoresonator for enhancement of 2D material photoluminescence

Nowadays the volume of transmitted information exponentially grows and requires the development of new telecommunication systems. Dielectric nanoresonators can be considered as a basic part of such systems to control the emission of the nanoscale source. Here we numerically investigated resonant dielectric nanoresonators for emission enhancements of 2D nanomaterials. We show that the radiative Purcell factor can achieve the value of up to 21 and 12 for the magnetic quadrupole and dipole responses, respectively. Also, we compare the directivity patterns for magnetic dipole and quadrupole resonances. The results obtained in this work can be applied in the development of optical chips and interfaces.

Investigation the dynamic of nano quantum cascade lasers with optoelectronics feedback

In this paper, a theoretical investigation of negative optoelectronic feedback study in Nano quantum cascade lasers is presented. The present rate equation model has been modified to include the nano laser factors such as the Purcell factor and the spontaneous emission factor. The results indicate that the present rate equation model can be using to study the effect of Purcell factor and the spontaneous emission factor on the negative optoelectronic feedback in Nano quantum cascade lasers. It is found that the increase in Purcell factor value leads to increase in photon number and decrease the carrier number in all quantum states. Also, the dynamic of photon number (S) tends to stable at constant value with the increase of Purcell effect i.e. there is small variation in photon number and carrier number( , , ). The decreases in enhanced spontaneous emission factor value leads to increases in carrier number and decreases the photon number and we note small variation in these values.

Anisotropic Purcell Factor Control of an Emitter in Graphene Under the Modulation of a Static Magnetic Field

Spontaneous emission control of emitters hold great promise for applications in pho-tonics and quantum optics. As a definition of the spontaneous emission lifetime of an atom or molecule, the Purcell factor of an emitter coupled with graphene plasmons by a static magnetic field is studied. The results show that the Purcell factor can be effectively modulated by the applying of external magnetic field to graphene at lower terahertz frequencies. In addition, in the presence of a magnetic field, the coupling between the graphene and emitter becomes stronger, which results in a strong enhancement of the emission of the emitter and the numerically calculated Purcell factor is increased. More specifically, the Purcell factor increases by almost an order of magnitude when the applied magnetic field is 10T. Moreover, the Purcell factor also depends on the polarization direction of the emitter, especially when the polarization direction of the emitter is parallel to the graphene plane, the Purcell factor will show anisotropy with the change of polarization angle. Bias of the applied magnetic field extends a new path for the realization of Purcell factor modulation based on graphene-emitter interaction, it may provides a promising application value for the design of the photo-magnetic based quantum devices.

Multipolar-sensitive engineering of magnetic dipole spontaneous emission with a dielectric nanoresonator antenna

We propose an axisymmetric silicon nanoresonator with designed tapered angle well for the extraordinary enhancement of the decay rate of magnetic dipole (MD) emitters. Due to the resonant coupling of a MD emitter and the MD mode of the subwavelength resonator, the Purcell factor (PF) can easily reach 500, which is significantly higher than the PF when using a silicon nanosphere of the same size. The PF and the resonance frequency are conveniently tuned through the resonator diameter and the taper angle of the blind hole. When supported by a metallic substrate, further enhancement ($$>10^3$$ > 10 3 ) of the MD spontaneous emission is triggered by an image-induced quadrupolar high-Q mode of the nanoantenna. For the sake of comparison we include a critical analysis of the canonical problem that considers a Si spherical shell. Our results might facilitate a novel strategy for promising realizations of chip-scale nanophotonic applications.