Photonic Crystal Defect Research Articles

Advanced dry etching of GaAs/AlGaAs multilayer wafer with InAs quantum dot for circular defect in photonic crystal laser

We previously proposed the circular defect in two-dimensional photonic crystal (CirD) laser based on a GaAs/AlGaAs multilayer wafer, which is fabricated by dry etching. This CirD laser uses InAs quantum dot (QD) layers as the gain medium, but this inhibits vertical dry etching. We improved the dry etching process by introducing three QD layers and three-step dry etching for fabricating the CirD laser. As a result, CirD structures with good etching profiles could be fabricated and excellent optical properties were obtained. We observed lasing by a CirD laser fabricated by deep etching under photoexcitation measurement for the first time.

Employing metamaterial and Ti3C2Tx (MXene) material for cancer cells detection using defective 1D photonic crystal

Employing metamaterial and Ti3C2Tx (MXene) material for cancer cells detection using defective 1D photonic crystal

Highly boosted trace-amount terahertz vibrational absorption spectroscopy based on defect one-dimensional photonic crystal.

Although terahertz (THz) spectroscopy demonstrates great application prospects in the fields of fingerprint sensing and detection, traditional sensing schemes face unavoidable limitations in the analysis of trace-amount samples. In this Letter, a novel, to the best of our knowledge, absorption spectroscopy enhancement strategy based on a defect one-dimensional photonic crystal (1D-PC) structure is proposed to achieve strong wideband terahertz wave-matter interactions for trace-amount samples. Based on the Fabry-Pérot resonance effect, the local electric field in a thin-film sample can be boosted by changing the length of the photonic crystal defect cavity, so that the wideband signal of the sample fingerprint can be greatly enhanced. This method exhibits a great absorption enhancement factor, of about 55 times, in a wide terahertz frequency range, facilitating the identification of different samples, such as thin α-lactose films. The investigation reported in this Letter provides a new research idea for enhancing the wide terahertz absorption spectroscopy of trace samples.

Pressure Sensing of Symmetric Defect Photonic Crystals Composed of Superconductor and Semiconductor in Low-Temperature Environment

We theoretically investigate the defect mode transmittance of light waves in superconductor–semiconductor photonic crystals and its pressure-sensing dependence. The photonic crystal is composed of alternating superconducting and semiconducting slabs and a defect locates at the center of this structure. Two trapezoid waveguides are fixed at both sides of the crystal, which induces the hydrostatic pressure applied and beams transmitted simultaneously. The resonant wavelength variation in the defect mode is directly proportional to the pressure applied on the system in the near-IR region, which can be utilized for linear pressure sensors in the cryogenic environment. Pressure sensitivity reaches a high value of 2.6 nm/GPa, which is higher than that in the study based on the reflection spectra. The sensitivity coefficient may be modulated by the environment temperature as well. This study has potential regarding pressure-light-wave sensors.

Tunable Fano resonance in coupled topological one-dimensional photonic crystal heterostructure and defective photonic crystal

In this paper, we theoretically investigate the transmission properties of a structure composed of a topological one-dimensional photonic crystal (1D PhC) heterostructure and a conventional 1D PhC containing indium-antimonide (InSb) as a defect layer using the transfer matrix method. The phenomenon of Fano resonance can be achieved by coupling the defect mode with the topological edge state mode, which is supported by the topological PhC. The numerical results show that a narrow Fano resonance is observed in the transmission spectrum of the structure in the presence of the external magnetic field applied to the InSb defect layer. The optical properties of the InSb defect layer, and, therefore, the Fano resonance, can be dynamically controlled by changing the applied external magnetic field. The results obtained with the proposed structure reveal that the magnetic field has the greatest influence on controlling the optical properties of the Fano resonance. These findings could be beneficial for optical devices such as optical filters, sensors, and optical switches.

Temperature Sensing Based on Defect Mode of One-Dimensional Superconductor-Semiconductor Photonic Crystals

Based on the transfer-matrix method, we theoretically explore the transmission and reflection properties of light waves in a one-dimensional defective photonic crystal composed of superconductor (HgBa2Ca2Cu3O8+δ) and semiconductor (GaAs) layers. The whole system is centrosymmetric and can generate a defect transmission peak in the photonic band gap. We study the effect of the temperature on the defect mode. Results obtained show that the defect mode shifts to the lower frequency regions as the value of the environmental temperature increases, and the resonance of the defect mode can be strengthened further as the number of periods increases. In addition, our findings reveal that the central wavelength of the defect mode increases with the increase in the environmental temperature and it presents a nearly linear relationship between the central wavelength of the defect mode and the temperature in cryogenic environments. Therefore, we can use the temperature response of the defect mode to detect the temperature. It is hoped that this study has potential applications for the development of cryogenic sensors with high sensitivity.

Unidirectional transmission analysis of all-optical routers with asymmetric structured photonic crystals based on FDTD

The unidirectional transmission behavior of photonic crystal (PC) consisting of defect pairs is investigated by the finite-difference time-domain (FDTD) method. By selecting the appropriate size proportion of the constitutional PC defects and changing the power intensity of the incident light, the transmission contrast as well as the maximum transmission can be significantly improved. The simulation results are supported by the coupled-mode theory(CMT). This conclusion provides a reference for the design of an all-optical router with low insertion loss.

The role of the defect in photonic crystals based on WS2 or WSe2 monolayers: a vision on how to achieve high quality factor and wavelength adjustability in defect modes

The role of the defect in photonic crystals based on WS2 or WSe2 monolayers: a vision on how to achieve high quality factor and wavelength adjustability in defect modes

Investigating wavelength bandwidth of orthogonal lattice waveguide for circular defect in two-dimensional photonic crystal (CirD) lasers

To achieve wavelength division multiplexing of optical communications for short distances, we have theoretically investigated a photonic crystal waveguide we call an orthogonal lattice waveguide (OLW), which may have a communication wavelength bandwidth of about 20 nm. In this paper, we fabricate CirD laser structures with air-cladding layers and OLWs of different cavity radii. We confirm that the light emitted from the OLW is the light generated in the cavity. OLW has a wavelength bandwidth of about 20 nm, which agrees with the results of our previous theoretical study. The wavelength shift is about 4 nm when the radius of the circular defect cavity increases by 0.01 a, where a is the lattice constant.

Sensing and Detection Capabilities of One-Dimensional Defective Photonic Crystal Suitable for Malaria Infection Diagnosis from Preliminary to Advanced Stage: Theoretical Study

In the present research work we have examined the biosensing capabilities of one-dimensional photonic crystals with defects for the detection and sensing of malaria infection in humans by investigating blood samples containing red blood cells. This theoretical scheme utilizes a transfer matrix formulation in addition to MATLAB software under normal incidence conditions. The purpose of considering normal incidence is to rule out the difficulties associated with oblique incidence. We have examined the performance of various structures of cavity layer thicknesses 1000 nm, 2200 nm, 3000 nm and 5000 nm. The comparison between the performances of various structures of different cavity thickness helps us to select the structure of particular cavity thicknesses giving optimum biosensing performance. Thus, the proper selection of cavity thickness is one of the most necessary requirements because it also decides how much volume of the blood sample has to be poured into the cavity to produce results of high accuracy. Moreover, the sensing and detection capabilities of the proposed design have been evaluated by examining the sensitivity, figure of merit and quality factor values of the design, corresponding to optimum cavity thickness.

Rod and slit photonic crystal microrings for on-chip cavity quantum electrodynamics

Abstract Micro-/nanocavities that combine high quality factor (Q) and small mode volume (V) have been used to enhance light–matter interactions for cavity quantum electrodynamics (cQED). Whispering gallery mode (WGM) geometries such as microdisks and microrings support high-Q and are design- and fabrication-friendly, but V is often limited to tens of cubic wavelengths to avoid WGM radiation. The stronger modal confinement provided by either one-dimensional or two-dimensional photonic crystal defect geometries can yield sub-cubic-wavelength V, yet the requirements on precise design and dimensional control are typically much more stringent to ensure high-Q. Given their complementary features, there has been sustained interest in geometries that combine the advantages of WGM and photonic crystal cavities. Recently, a “microgear” photonic crystal ring (MPhCR) has shown promise in enabling additional defect localization ( > $ > $ 10× reduction of V) of a WGM, while maintaining high-Q ( ≈ 1 0 6 ) $(\approx 1{0}^{6})$ and other WGM characteristics in ease of coupling and design. However, the unit cell geometry used is unlike traditional PhC cavities, and etched surfaces may be too close to embedded quantum nodes (quantum dots, atomic defect spins, etc.) for cQED applications. Here, we report two novel PhCR designs with “rod” and “slit” unit cells, whose geometries are more traditional and suitable for solid-state cQED. Both rod and slit PhCRs have high-Q ( > 1 0 6 ) $( > 1{0}^{6})$ with WGM coupling properties preserved. A further ≈10× reduction of V by defect localization is observed in rod PhCRs. Moreover, both fundamental and 2nd-order PhC modes co-exist in slit PhCRs with high Qs and good coupling. Our work showcases that high-Q/V PhCRs are in general straightforward to design and fabricate and are a promising platform to explore for cQED.

High performance biosensor composed of 1D defective photonic crystal for sensing and detection of distinguished blood components

High performance biosensor composed of 1D defective photonic crystal for sensing and detection of distinguished blood components

Design of Temperature Sensor Based on One-Dimensional Photonic Crystal Containing Si–BGO Layer

This paper describes the theoretical investigation of enhancement in temperature sensitivity using one-dimensional (1D) symmetric defective photonic crystal (PC) containing Si (Silicon) and Bi4Ge3O[Formula: see text] (Bismuth Germanate, BGO) material. The proposed sensor consists of a defect layer (air defect) sandwiched between two 1D-PCs with a symmetrical and asymmetrical structure composed of Si and BGO, respectively. Sensor performance has been evaluated by calculating the transmittance spectra of the proposed structure. In order to obtain the transmittance spectra, a transfer matrix method (TMM) is employed. The principle of temperature sensing is based on the shift in the resonant wavelength (or peak) of the transmission mode with a change in temperature. This is due to the temperature-dependent refractive index of the Si and BGO layers. Analysis of the transmittance spectra shows that temperature sensitivity of 1D-PC structure can be enhanced by using a symmetric defective PC with and without an external defect layer over asymmetric defective PC. It is found that symmetric defective PC with and without defect shows sensitivity equal to 0.173[Formula: see text]nm/[Formula: see text]C and 0.140[Formula: see text]nm/[Formula: see text]C, whereas asymmetric defective PC shows 0.125[Formula: see text]nm/[Formula: see text]C, for the same parameters. Further, the results show that symmetric defective 1D-PC (without the presence of any external defect layer) gives a higher [Formula: see text]-factor than a symmetric and asymmetric defective 1D-PC with an external defect layer. The proposed structure is cost-effective, easy to fabricate and compact in size.

A doped-polymer based porous silicon photonic crystal sensor for the detection of gamma-ray radiation.

In this research, a theoretical investigation of the one-dimensional defective photonic crystals is considered for the detection of gamma-ray radiation. Each unit cell of the considered one-dimensional photonic crystals (1D PhCs) is composed of two layers designed from porous silicon infiltrated by poly-vinyl alcohol polymer doped with crystal violet (CV) and carbol fuchsine (CF) dyes (doped-polymer) with different porosity. In addition, a single layer of doped-polymer is included in the middle of the designed 1D PhCs to stimulate the localization of a distinct resonant wavelength through the photonic band gap. In particular, the appearance of this resonant mode represents the backbone of our study towards the detection of γ-ray radiation with doses from 0 to 70 Gy. The Bruggeman's effective medium equation, the fitted experimental data to the refractive index of the doped-polymer, and the Transfers Matrix Method (TMM) serve as the mainstay of our theoretical treatment. The numerical findings provide significant contributions to some of the governing parameters such as the thicknesses of the considered materials on the performance of the presented sensor, the effect of incidence angle and the porosity of the considered materials on the resonance wavelength. In this regard, at optimum values of these parameters the sensitivity, quality factor, signal-to-noise ratio, detection limit, sensor resolution, and figure of merit that are obtained are 205.7906 nm RIU-1, 9380.483, 49.315, 2.05 × 10-5 RIU, 3.27 × 10-5, and 2429.31 RIU-1, respectively. Therefore, we believe that the suggested design could be of significant interest in many industrial, medical, and scientific applications.

Wavelength-control of multi-narrowband high absorbers using symmetric and asymmetric photonic crystals with two MoS2-based defects

Wavelength control of multi-narrowband absorbers plays a pivotal role in photonic devices. Such absorbers have been designed and constructed using highly absorbent layers. Ultra-thin layers of two-dimensional (2D) nanomaterials, such as MoS2, which are highly absorbent materials, have found attractive applications in photonics. In this study, defective photonic crystals (DPC) with two defects were formed by DMD with M and D indicating MoS2 and SiO2 layers, respectively. The calculation method used in this paper is the transfer matrix method (TMM). This paper proposes that symmetric and asymmetric DPCs with respect to each defect layer affect the number of defect modes, which ranges from one to four. Furthermore, changing the number of MoS2, defect positions, and thickness significantly impact the absorption, wavelength, and quality factor of the defect modes. In addition, changing the polarization and incident angle causes the wavelength of the defect modes to shift towards blue and changes the peak-to-peak distance. The distance between the defects provides wavelength adjustability, and the polarization and incident angle provide wavelength turnability. Moreover, changing the thickness of the D layer provides a redshift in the wavelength of the defect modes. The location of the defect layer, symmetry or asymmetry of DPCs affect the number and wavelength of defect modes. Increasing of distance between defects provides the same mechanism as a DPC with one defect. Also, photonic band gap does not depend on the thickness of the defect layer, the symmetry or asymmetry of the structure, periodicity of the top, middle, and bottom defect layer of DMD. This controllable design of multi-narrowband defect modes is likely to find numerous applications in multi-channel absorbers and sensors.

Eigenfunction and eigenmode-spacing statistics in chaotic photonic crystal graphs.

The statistical properties of wave chaotic systems of varying dimensionalities and realizations have been studied extensively. These systems are commonly characterized by the statistics of the eigenmode spacings and the statistics of the eigenfunctions. Here, we propose photonic crystal (PC) defect waveguide graphs as a physical setting for chaotic graph studies. Photonic crystal waveguides possess a dispersion relation for the propagating modes, which is engineerable. Graphs constructed by joining these waveguides possess junctions and bends with distinct scattering properties. We present numerically determined statistical properties of an ensemble of such PC graphs including both eigenfunction amplitude and eigenmode-spacing studies. Our proposed system is compatible with silicon nanophotonic technology and opens chaotic graph studies to a new community of researchers.

Intensity modulation mechanism of parity-time symmetric photonic crystal coupled resonators

In order to study the application of transmission enhancement effect in photonic crystals, a novel sensing structure based on parity-time (PT) symmetry is proposed, in which a circular resonant cavity is introduced into the defect photonic crystal. By introducing the resonant cavity into the one-dimensional periodic photonic crystal with defect layer, the electric field is better localized in it, and the intensity of structural transmittance is greatly improved, namely transmission enhancement.Unlike the traditional optical sensing detection, the change of resonance peak caused by the detection quantity in the transmission spectrum is much more significant than the shift of resonance wavelength position, so the transmittance is used as the direct detection quantity. Through simulation and reasonable design of various structural parameters, the peak transmittance of the structure comes 400.7, the sensitivity reaches 1.34 × 105 RIU−1, which dramatically improves the detection sensitivity and changes the principle that the traditional optical sensor takes the shift of resonance wavelength as the direct detection quantity, so that the PT symmetry principle can be better applied to the optical structure.

Tunable properties of the defect mode of a ternary photonic crystal with a high T C superconductor and semiconductor layers

Abstract The tuning of a defect mode in a photonic crystal (PC) is of high significance for filter and sensor applications. We here investigate the tuning of the defect mode of a defective ternary PC with a semiconductor and high critical-temperature superconductor layers. A ternary photonic crystal with the heterostructure (semiconductor/superconductor/dielectric) is assumed. The transfer matrix method is employed to investigate the transmission of transverse electric waves. The refractive indices of the semiconductor and superconductor layers can be tuned by changing the operating temperature and the hydrostatic pressure. The defect mode and transmission properties can be controlled by using the hydrostatic pressure, operating temperature, frequency and thicknesses of the heterostructure layers. The analysis is performed in the frequency range of 20–65 THz. The proposed structure can be utilized as a biosensor and a narrowband transmission peaks filter.

Detection of Hemoglobin Concentration Based on Defective One-Dimensional Photonic Crystals

The significance of the optical biosensor is its ability to detect biomolecules in their natural form. Among them, photonic crystal-based biosensors analyze the refractive index changes due to molecular interaction, and that is correlated to the sample concentration instead of sample mass. In this paper, we report the sensing performance of a one-dimensional photonic crystal-based sensor for the detection of hemoglobin concentration using an asymmetric periodic structure with a single defect. We have used the transfer matrix method to analyze the reflectance properties of the photonic crystal. The resonant dip in the spectra and its shift with hemoglobin concentration is the basis of our sensor design. The proposed sensor is efficient in sensing hemoglobin concentration, the sensitivity and other sensor parameters were derived numerically, and the obtained parameters are comparable to the many of the reported values of photonic crystal-based sensors. The dependence of the defect layer thickness on the position of resonant dips and sensitivity is also demonstrated in our work. The numerical results prove that these photonic crystal biosensors are simple, cost effective and highly accurate for detecting the hemoglobin concentration.

A new insight into defective one-dimensional dielectric-graphene photonic crystals

The transmission properties of a defective one-dimensional dielectric-graphene stack are investigated by employing the transfer matrix method in the THz frequency range. The structure containing silicon dioxide as a defect layer consists of polyethylene and graphene nano-layers arranged in the pattern of (AG) N D(GA) M . The effect of the iteration numbers on the defect mode properties is studied to optimize the transmission peak. Analyzing structure with optimal iteration numbers indicates that the full width of half maximum is highly decreased. Subsequently, the quality factor is substantially enhanced as the thickness of the defect layer increases. It is also discussed how several parameters such as the incident angle, the state of polarization, and the permittivity of the layers affect the defect mode’s behavior. Our findings show that only in the case of ϵ A < 3 one can obtain the localized defect mode at frequencies between 1 and 2 THz. We also study the transmission characteristics with a focus on the variation of permittivity of the constituent layers. By increasing the incident angle, the peak intensity for the TM-polarized wave grows slightly, while it decreases for the TE-polarized wave. However, these changes are more striking in the case of ϵ A = 1 as compared to those in the case of ϵ A = 2.25. Photonic devices utilizing such defective structures may find application in filters and sensors operating in the THz range.