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Quantitative Analysis of Photon Density of States for One-Dimensional Photonic Crystals in a Rectangular Waveguide
摘要： Light propagation in one-dimensional (1D) photonic crystals (PCs) enclosed in a rectangular waveguide is investigated in order to achieve a complete photonic band gap (PBG) while avoiding the difficulty in fabricating 3D PCs. This work complements our two previous articles (Phys. Rev. E) that quantitatively analyzed omnidirectional light propagation in 1D and 2D PCs, respectively, both showing that a complete PBG cannot exist if an evanescent wave propagation is involved. Here, we present a quantitative analysis of the transmission functions, the band structures, and the photon density of states (PDOS) for both the transverse electric (TE) and transverse magnetic (TM) polarization modes of the periodic multilayer heterostructure confined in a rectangular waveguide. The PDOS of the quasi-1D photonic crystal for both the TE and TM modes are obtained, respectively. It is demonstrated that a “complete PBG” can be obtained for some frequency ranges and categorized into three types: (1) below the cutoff frequency of the fundamental TE mode, (2) within the PBG of the fundamental TE mode but below the cutoff frequency of the next higher order mode, and (3) within an overlap of the PBGs of either TE modes, TM modes, or both. These results are of general importance and relevance to the dipole radiation or spontaneous emission by an atom in quasi-1D periodic structures and may have applications in future photonic quantum technologies.
关键词： TE,PDOS,photonic crystals,waveguide,photonic band gap,TM,complete PBG
更新于2025-09-11 14:15:04
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DESIGNING PLANE WAVE MODULATORS USING 1DPC NANOSTRUCTURE WITH R-GRIN DEFECT LAYER
摘要： In this paper, we introduce plane wave modulators that are designed using one-dimensional photonic crystals (1DPC) containing radial gradient refractive index (r-GRIN) defect layers. Three kinds of r-GRIN materials with di?erent refractive index distribution functions are applied in numerical analysis. The properties of the phase and intensity of the transmitted plane wave beam through proposed structures are studied using the transfer matrix method. Radially-dependent defect modes, modulated phase and intensity are obtained according to the refractive index distribution functions. The results are predictable by regarding the Bragg condition and destructive interference, which are the origins of the photonic band gap (PBG). Due to the radial-dependency of the defect layer’s refractive index, the rays passing through di?erent transverse positions experience di?erent optical pathways. Therefore, the defect modes and transmitted spectrum (phase and amplitude) vary transversely. This study demonstrates another ability of the arti?cial PC structures to design plane wave modulators and manipulate its phase and intensity.
关键词： radial gradient refractive index,transfer matrix method,one-dimensional photonic crystals,plane wave modulators,photonic band gap
更新于2025-09-04 15:30:14
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Light energy accumulation by cholesteric liquid crystal layer at oblique incidence
摘要： Oblique propagation of light through a planar layer of a cholesteric liquid crystal (CLC) is solved by Ambartsumian’s modified layer addition method. Two cases are considered, namely, the case when dielectric boundaries have a minimum influence on light transmission and the case when the CLC layer is in a vacuum. It is shown that in the first case a total internal reflection can happen for the fast eigen-mode at large incidence angles. New important features of light reflection (transmission) spectra, photonic density of states and accumulated energy density in the CLC layer are studied. The light localisation peculiarities in the CLC layer at oblique incidence is investigated too. It is shown that the light localisation for both the long-wavelength edge mode and the short-wavelength edge mode changes differently when the incidence angle changes. The obtained results can be used in the design of low-threshold lasers, in solar cell systems, in chiral photonics, in systems strongly absorbing light at certain wavelengths and when designing systems with absorption suppression created on the base of absorbing media, etc.
关键词： total internal reflection,Cholesteric liquid crystals,photonic band gap,light localisation
更新于2025-09-04 15:30:14
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NUMERICAL INVESTIGATION ON THE SPECTRAL PROPERTIES OF ONE-DIMENSIONAL TRIADIC-CANTOR QUASI-PERIODIC STRUCTURE
摘要： We numerically investigate the optical spectra of a photonic band gap material realized by one-dimensional Triadic-Cantor quasi-periodic structure. The studied system is composed of two elementary layers H and L with refractive indices nL = 1.45 (SiO2) and nH = 2.3 (T iO2), respectively. Analytical calculations using a trace and antitrace maps approach have been used to ?nd the re?ection and transmission theoretical expressions in visible range under quarter wavelength condition. In our results we present the e?ect of iteration order of Triadic-Cantor sequence on the optical properties of these multilayer systems, namely the photonic band gap behavior and the optical windows presence, which makes this type of structures good candidates for interesting applications in the ?eld of the nano-optical Engineering.
关键词： trace and antitrace maps,Triadic-Cantor,optical properties,quasi-periodic structure,photonic band gap
更新于2025-09-04 15:30:14