Slow light bimodal interferometry in one-dimensional photonic crystal waveguides

Compact, wide bandwidth, multi-channel power dividers based on one-dimensional photonic crystal waveguides

We propose a compactly integrated transverse-magnetic (TM)-pass polarizer based on rectangular-shape onedimensional photonic-crystal silicon waveguide with an extremely high polarization extinction ratio of >30 dB and low insertion loss (~1 dB) over a broad wavelength range of 210 nm from 1,460 nm to 1,670 nm. The polarizer has been numerically simulated using three-dimensional finite-difference time-domain (3D FDTD) method. The optimum length of the proposed TM-pass polarizer is about 4 μm. At the 1,550 nm wavelength, the simulated polarization extinction ratio of the polarizer is 36 dB, and its corresponding insertion loss is about 1 dB.

Using cold atoms to simulate strongly interacting quantum systems represents an exciting frontier of physics. However, as atoms are nominally neutral point particles, this limits the types of interactions that can be produced. We propose to use the powerful new platform of cold atoms trapped near nanophotonic systems to extend these limits, enabling a novel quantum material in which atomic spin degrees of freedom, motion, and photons strongly couple over long distances. In this system, an atom trapped near a photonic crystal seeds a localized, tunable cavity mode around the atomic position. We find that this effective cavity facilitates interactions with other atoms within the cavity length, in a way that can be made robust against realistic imperfections. Finally, we show that such phenomena should be accessible using one-dimensional photonic crystal waveguides in which coupling to atoms has already been experimentally demonstrated.

We consider a one-dimensional photonic crystal (1DPC) composed of double-layered dielectrics. Electric permittivity and magnetic permeability of this crystal depends on the incident electromagnetic wave frequency. We suppose that three level atoms have been added to the second layer of each dielectric and this photonic crystal (PC) has been doped. These atoms can be added to the layer with different rates. In this paper, we have calculated and compared the band structure of the mentioned PC considering the effect of added atoms to the second layer with different rates through the Fresnel coefficients method. We find out that according to the effective medium theory, the electric permittivity of the second layer changes. Also the band structure of PC for both TE and TM polarizations changes, too. The width of bandgaps related to “zero averaged refractive index” and “Bragg” increases. Moreover, new gap branches appear in new frequencies at both TE and TM polarizations. In specific state, two branches of “zero permittivity” gap appear in the PC band structure related to TM polarization. With increasing the amount of the filling rate of total volume with three level atoms, we observe a lot of changes in the PC band structure.

The study is devoted to closed and transferred electromagnetic field in one-dimensional both transparent photonic crystals and crystals containing layers which absorb irradiation alternated by transparent layers. General theory of irrdiation closed inside the crystal is developed both in case transparent and adsorbing metallic photonic crystals in wide frequency range. True or absolute photonic gaps existing in the total reflection angle range are analyzed on the base of internal problem's analytical solution for 1D layered superlattices. We have investigated the frequency-angle diagrams for TM and TE photonic spectra trapped inside the whole reflection range for mesoscopic and macroscopic hierarchical 1D photonic crystals of varied topologies, geometry and materials. The effects of double refraction in binary multi-layered system and photon localization in finite periodic layered structures are investigated analytically and numerically. Energy storage and energy decay time in photonic crystals are considered with account for field amplitudes distribution inside the structure and angular band kinetics. The effect of sharp focusing of the butt-end emission for closed electromagnetic waves in 1D photonic crystals is discussed.

Omnidirectional narrow-band ultraviolet filtering based on one-dimensional defective photonic crystal containing hyperbolic metamaterial

A couple structure composed of one-dimension photonic crystal and meta-materials realized by composite right-/left-handed transmission line (CRLH TL) is constructed by using transmission line approach. The CRLH TL exhibits a broad left-handed passband, with anti-parallel phase and group velocities. Moreover, the left-handed passband can be adjusted by the L-C elements and the unit length. The one-dimension photonic crystal is made of alternating microstrip rings and microstrip line. And the photonic passband and the stopband are determined by the lattice constant. In this paper, the first and second passbands of the photonic crystal are of interest. The coupling characteristics between the left-handed metamaterial and the photonic crystal in the first passband closely resemble that in the second passband. It is clearly observed that the coupling characteristics between left-handed metamaterial and the photonic crystal in the two passbands are similar with that between the left-handed material and the right-handed material. The photonic crystal should be regarded as a right-handed material in (the first and second) passband.

Using transfer matrix method, the optical transmission properties in one-dimensional (1-D) photonic crystal is analyzed. When the temperature varies, not only the refractive index of the optical medium is changed because of the thermo-optical effect, but also the thickness of the optical medium is changed due to the thermal-expansion effect. Thus, the structure of 1/4 wave-plate stack in original photonic crystal is destroyed and the band structure varies. In this work, the effects of the temperature variation on the first and second band gap in a 1-D photonic crystal are analyzed in detail. It is found that the changes of the starting wavelength, the cut-off wavelength and the forbidden band width depend linearly on the temperature.

One-dimensional dielectric photonic crystals (PCs) with complex substitutional defect layers, consisting of superconducting (SC) and dielectric sublayers are theoretically studied. The influence of the incidence angle on the photonic gap spectra is theoretically analyzed. The pronounced difference in the transmittivity spectra of the PCs with right-handed (RH) and left-handed (LH) positions of the superconducting defect sublayer with respect to the dielectric defect sublayer is demonstrated. It is observed that, for the case of RH SC defect sublayer, the position of the defect mode and the transmittivity at the defect mode frequency strongly depend on the thickness of the superconducting sublayer as well as on the temperature. But the defect modes of the PCs with LH SC defect sublayer are nearly invariant upon the change of the thickness of the superconducting sublayer and the temperature.

Multi-channel photonic bandgap engineering in hyperbolic graded index materials embedded one-dimensional photonic crystals

Defect mode properties in a one-dimensional photonic crystal

In this work, the guided modes of a photonic crystal polarization beam splitter (PC-PBS) are studied. We demonstrate that the transmission of a low-loss photonic crystal 120° waveguide bend integrated with the PBS will be influenced if the PBS is multi-moded. We propose a single-moded PC-PBS structure by introducing deformed structures, and it shows twice the enhancement of the transmission. This device with remarkable improvement of performance is promising in the use of photonic crystal integrated circuits design.

Weyl semimetals, a class of topological materials exhibits significant optical non-reciprocity without the need for an external magnetic field or high-intensity light sources. Adding Weyl semimetal layers to a one-dimensional photonic crystal as defect layers may improve the structure’s non-reciprocity. This study investigates the influence of chirping on the non-reciprocal temporal evolution of Gaussian pulses in a one-dimensional photonic crystal with double-layer defects composed of silicon dioxide and Weyl semimetal. Using the transfer matrix method and Fourier transform, we analyze the transmission spectrum and pulse dynamics under linear and quadratic chirping conditions. The structure exhibits a photonic band gap with two defect modes whose resonant frequencies shift depending on the incident direction (forward or backward), demonstrating strong optical non-reciprocity. Chirping induces rapid oscillations in the transmitted pulse profile, with quadratic chirping causing more pronounced distortions than linear chirping. While non-chirped pulses retain their shape, chirped pulses undergo compression, decompression, or multi-peak formation, depending on the chirp type and carrier frequency. The temporal evolution of pulses is highly sensitive to the incident direction and carrier frequency, with forward-propagating pulses tuned to defect modes showing compression, whereas backward-propagating pulses exhibit decompression or oscillatory tails. Quadratic chirping introduces stronger modifications to pulse profiles compared to linear chirping, highlighting its potential for advanced pulse shaping in non-reciprocal systems. These findings highlight the critical role of chirping in controlling pulse propagation in defective photonic crystals, offering insights for applications in optical isolation, signal processing, and tunable photonic devices.

The water content sensor in heavy oil based on one-dimensional photonic crystals

In present study, the effect of different defect layer refractive indices and thicknesses on group velocity has been studied in one-dimensional photonic crystal. It is found that the increase of refractive index, number of defects and defect layer thickness will induce the decrease of group velocity. Taking advantage of these results, a novel technique has been introduced to tune and control the slowing light in photonic crystal