We present analytical and numerical results on the formation properties of leaky stop band in one-dimensional photonic lattices. At second band, one edge mode suffers radiation loss generating guided-mode resonance whereas other becomes a non-leaky bound-state continuum. show that frequency location edge, correspondingly is determined by superposition Bragg processes generated first two Fourier harmonics spatial dielectric constant modulation. closed-band state, we discover an analytic...

Abstract When two nonorthogonal resonances are coupled to the same radiation channel, avoided crossing arises and a bound state in continuum (BIC) appears with appropriate conditions parametric space. This paper presents numerical analytical results on properties of BIC due guided-mode one-dimensional (1D) leaky-mode photonic lattices slab geometry. In symmetric up-down mirror symmetry, Friedrich–Wintgen BICs infinite lifetime accompanied by crossings coupling between guided modes transverse...

Abstract Bound states in the continuum (BICs) theoretically have ability to confine electromagnetic waves limited regions with infinite radiative quality ( Q ) factors. However, practical experiments, resonances can only exhibit finite factors due unwanted scattering losses caused by fabrication imperfections. Recently, it has been shown that ultrahigh‐ guided‐mode (GMRs), which are robust imperfections, be realized merging multiple BICs momentum space. This study analytically and...

Abstract Unidirectional light emission from planar photonic structures is highly advantageous for a wide range of optoelectronic applications. Recently, it has been demonstrated that unidirectional guided resonances (UGRs) can be realized by utilizing topological polarization singularities in momentum space. However, the practical application these emitters limited due to their intricate geometric configurations, requiring special efforts with high‐cost fabrication processes. In this study,...

We show that line defects can give rise to the bending and splitting of self-collimated beams in two-dimensional photonic crystals from equifrequency contour calculations finite-difference time-domain simulations. The power ratio between two split be controlled systematically by varying radii rods or holes defect. also controllable useful steering flow light crystal integrated circuits.

We propose a method to design antireflection structures minimize the reflection of light beams at interfaces between two-dimensional photonic crystal and homogeneous dielectric. The parameters optimal structure give zero can be obtained from one-dimensional coating theory finite-difference time-domain simulations. examine performance Mach-Zehnder interferometer utilizing self-collimated in crystals with without introduced. It is shown that significantly improves device.

We present a novel, electromagnetically induced transparency system based on guided-mode resonances and numerically demonstrate its transmission characteristics through finite-difference time-domain simulations. The is composed of two planar dielectric waveguides subwavelength grating. It shown that by coupling the resonant guide modes with low- high-quality factor, narrow window generated inside broad background dip produced resonance. Our work could provide another efficient way toward...

Abstract Highly stable and bright single‐photon emitters at room temperature are fundamental components of quantum information technologies, which support advanced applications such as computing, communication, sensing. A key challenge in realizing these technologies is the creation efficient sources capable emitting across a broad spectral range. While defect‐based materials diamond, SiC, 2D III‐nitrides show significant promise, broadband extraction remains considerable obstacle, often...

A two-dimensional photonic crystal asymmetric Mach-Zehnder filter (AMZF) based on the self-collimation effect is studied by numerical simulations and experimental measurements in microwave region. self-collimated beam effectively controlled employing line-defect splitters mirrors. The measured transmission spectra at two output ports of AMZF sinusoidally oscillate with phase difference pi frequency range. Position peaks dips can be varying size defect rod perfect mirrors, therefore this used...

We present a tunable notch filter having wide terahertz (THz) frequency range and low-pass (LPF) 0.78 THz cutoff frequency. Single slit multiple slits are positioned at the center of air gaps in tapered parallel-plate waveguides (TPPWG) to obtain LPF, respectively. The has dispersion-free low-loss transverse magnetic (TM) mode. Q factor was proved be 138, resonant is easily by adjusting between TPPWG. On other hand, cut off LPF determined using Bragg stop band, which depends on period....

Conventional photonic lattices, such as metamaterials and crystals, exhibit various interesting physical properties that are attributed to periodic modulations in lattice parameters. In this study, we introduce novel types of namely Fourier-component-engineered metasurfaces, do not possess the first Fourier harmonic component We demonstrate these metasurfaces support continuous high-$Q$ bound states near second stop bands. The concept engineering components provides a new method manipulate...

We present two photonic systems that make it possible to realize polarization-independent electromagnetically induced transparency based on guided-mode resonances. Each system is composed of planar dielectric waveguides and a two-dimensional crystal. Using finite-difference time-domain simulations, we demonstrate by coupling the resonances with low- high-quality factors, narrow window generated inside broad background transmission dip produced also show time delay occurs when light beams...

We present what we believe to be a novel high-efficiency photonic crystal polarization beam splitter that consists of polarizing slab embedded in two-dimensional self-collimating square lattice air holes silicon. The with the same constant as background exhibits not only high reflection for transverse electric (TE) and transmission magnetic (TM) polarization, but also extinction ratios both two-polarization output channels. Moreover, common antireflection structures TE TM polarizations are...

The characteristics of terahertz (THz) modulation in organic copper phthalocyanine thin films deposited on a Si wafer were investigated by angle-dependent photoexcitation. We reveal that the efficiency THz reflects not only reflectivity undergo change complex refractive index due to photoexcitation but also laser-induced birefringence induced charge density grating direction normal polarization excitation beams.

Optical eigenstates with a high quality (Q) factor provide substantial advantages for broad spectrum of optical devices, particularly those demanding strong light–matter interactions. Recently, it has been demonstrated that ultrahigh-Q resonances can be realized in planar photonic structures by merging multiple bound states the continuum (BICs) momentum space. Photonic lattices thin-film geometry are known to support abundant TE-polarized and TM-polarized BICs. While prior research explored...

We propose a ring-type Fabry-Pérot filter (RFPF) based on the self-collimation effect in photonic crystals. The transmission characteristics of self-collimated beams are experimentally measured this structure and compared with results obtained simulations. Bending splitting mechanisms light by line defects introduced into RFPF used to control beam. Antireflection structures also employed at input output crystal interfaces order minimize coupling loss. Reflectance line-defect beam splitters...

We present a high-efficiency antireflection structure for both TE and TM polarizations in two-dimensional self-collimating square lattice photonic crystal consisting of air holes silicon. The design parameters the optimal can be obtained by using concept Fresnel coefficients finite-difference time-domain simulations. operating almost identical self-collimation frequencies two exhibits large reflection coefficient very small one polarization. In this case, also improve transmission To confirm...

The propagation characteristics of spoof surface plasmon modes are studied in both real and reciprocal spaces. From the metallic square lattice, we obtain constant frequency contours by directly measuring electric fields microwave regime. anisotropy measured contour supports presence negative refraction self-collimation which confirmed from fields. Additionally, demonstrate beam splitter splitting ratio self-collimated is controlled varying height rods.

External waves incident on a periodic metamaterial lattice couple to it at frequencies corresponding the leaky, or second, stop band. The resulting leaky-mode guided-mode resonance effects are useful in device design and spectral manipulation. Indeed, some of most important properties metamaterials associated with leaky stopband. Thus motivated, we treat band dynamics resonant photonic lattices. In particular, gap conditions for closure flips under multimode quantified. For symmetric...

The authors have experimentally demonstrated the bending and splitting phenomena of self-collimated microwave beams in a two-dimensional square lattice photonic crystal composed alumina rods. were achieved by introducing line defect crystal. power ratio two split can be controlled varying radii rods defect.

We experimentally confirm that the antireflection structures effectively minimize unnecessary reflections of self-collimated microwave beams at interfaces a two-dimensional photonic crystal, which is composed cylindrical alumina rods. Optimized design parameters for are obtained from one-dimensional coating theory and finite-difference time-domain simulations. Measured transmittance through crystal samples with without agree well simulation results. The measured results show an structure...

We propose a novel structure for achieving highly efficient beaming of self-collimated light from two-dimensional photonic crystals. The finite-difference time-domain simulations show that both enhanced transmission and directional emission beams crystals are achieved by using the bending splitting in crystals, also introducing an antireflection coating-like crystal collimator to exit surface structure. This is potentially important coupling into conventional optical fibers waveguides.

We demonstrate that surface waves in structured perfect electric conductor surfaces can be self-collimated using the finite-difference time-domain method. The self-collimation frequency is obtained from equi-frequency contours of a patterned with an array square holes. field patterns wave, periodic boundary conditions, show propagate almost no spreading. also phenomena observed for hybrid plasmon metal method Drude model. It shown silver achieved at frequencies infrared region.

Bound states in the continuum (BICs) and Fano resonances planar photonic lattices, including metasurfaces photonic-crystal slabs, have been studied extensively recent years. Typically, BICs are associated with second stop bands open at second-order <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" id="m1"> <mml:mrow> <mml:mi mathvariant="normal">Γ</mml:mi> </mml:mrow> </mml:math> point. This paper addresses fundamental properties of fourth band accompanied by...