Photonic Crystal Structure Research Articles

High-power, stable single-mode CW operation of 1550 nm wavelength InP-based photonic-crystal surface-emitting lasers

1550 nm wavelength photonic-crystal surface-emitting lasers (PCSELs) are attractive for optical communication and eye-safe sensing applications. In this study, we present InP-based PCSELs featuring a double-lattice photonic-crystal structure designed for high-power single-mode operation at a wavelength of 1550 nm. These PCSELs demonstrate output powers exceeding 300 mW under continuous-wave conditions at 25 °C. Additionally, highly stable single-mode oscillation with a side-mode suppression ratio of over 60 dB is verified at temperatures from 15 °C to 60 °C. Measurement and simulation of photonic band structures reveal the impacts of the threshold gain margin and optical coupling coefficient on the single-mode stability.

Research on sensing characteristics of microfluidic sensor based on photonic crystal fiber

To address the challenges associated with sample injection into the air hole of photonic crystal fiber (PCF) and collimation, in this paper, we assemble a single-mode photonic crystal single-mode fiber structure sensor chip based on the Mach–Zehnder interference principle using microfluidic chip processing technology. The sensing principle is analyzed mathematically and the sensing characteristics are verified theoretically and experimentally. The temperature sensitivity of the sensor is −1.3325 nm °C−1, and the refractive index sensitivity is 1666.2 nm RIU−1. This structure solves the difficulty of filling and coupling PCFs. Furthermore, it introduces a novel research methodology for the design and assembly of high-performance biosensors based on PCFs.

The role of pores in structure of polyethylenglycol diacrylate based‐inverse opal photonic crystal in binding protein applicable to optical biosensor

AbstractHere, the role of pores in the structure of inverse opal photonic crystals (IOPC) in binding proteins in comparison with their parent photonic crystal (PC) templates has been investigated. For this purpose, polyethyleneglycol diacrylate (PEGDA) coated with SiO2‐based PC (PEGDA/SiO2‐based PC) and PEGDA‐based IOPC were attached with fluorophore Alexa 488, which is a polyclonal secondary antibody, to investigate their fluorescence emission. Scanning electron microscopy (SEM) images showed face centered cubic (fcc) packing of the PEGDA/SiO2‐based PC. And it remained after the formation of PEGDA‐based IOPC. The presence of 3‐aminopropyl triethoxysilane (APTES) and Alexa 488 that immobilized the PEGDA‐based PC and PEGDA‐based IOPC was recognized by the appearance of bands at 850, 1175, and a dominant increase in the band at 1750 cm−1. Those were attributed to (N─H) wagging, (C─N) stretching, and (C═O) stretching vibrations, respectively. Reflectance spectra showed a blue shift of the Bragg photonic band gap of the PEGDA‐based IOPC in comparison with that of the PEGDA/SiO2‐based PC. The fluorescence images showed a significant increase in the fluorescence intensity of PEGDA‐based IOPC owing to the resonance effect. These obtained results indicated the role of pores in structure of PEGDA‐based IOPC in improvement of the attachment of Alexa 488 protein.

Design and fabrication of a coupled high-Q photonic nanocavity system with large coupling coefficients.

In a previous work, we demonstrated a coupled cavity system where photons in one storage cavity can be transferred to another storage cavity at an arbitrary time by applying a voltage pulse to a third cavity placed in a p-i-n junction. In this work, we demonstrate methods to improve the transfer efficiency and photon lifetimes of such a coupled system. Firstly, we designed a photonic-crystal structure that achieves a large coupling coefficient without reducing the radiation quality factor compared to the previously proposed structure: The photonic-crystal design was changed to a more symmetric configuration to suppress radiation losses and then optimized using an automatic structure tuning method based on the Covariance Matrix Adaptive Evolutional Strategy (CMAES). Here we added two improvements to achieve an evolution toward the desired direction in the two-dimensional target parameter space (spanned by the coupling coefficient and the inverse radiation loss). Secondly, to improve the experimental cavity quality factors, we developed a fabrication process that reduces the surface contamination associated with the fabrication of the p-i-n junction: We covered the photonic structure with a SiO2 mask to avoid the contamination and the electrode material was changed from Al to Au/Cr to enable cleaning by a weak acid. Owing to these improvements of the cavity design and the fabrication process, the obtained system provides coupling strengths that are about three times stronger and photon lifetimes that are about two times longer, compared to the previously reported system.

Ultra-fast and compact optical Galois field adder based on the LPhC structure and phase shift keying.

In this study, we propose a novel, to the best of our knowledge, all-optical Galois field (AOGF) adder that utilizes logic all-optical XOR gates. The design is founded on optical beams' constructive and destructive interference phenomenon and incorporates the phase shift keying technique within a two-dimensional linear photonic crystal (2D-LPhC) structure. The suggested AOGF adder comprises eight input ports and four output ports. We employ the finite difference time domain (FDTD) procedure to obtain the electric field distribution in this structure. The FDTD simulation results of the proposed AOGF adder demonstrate that the minimum and maximum values of the normalized power at ON and OFF states (P 1,min, P 0,max) for the output ports are 95% and 1.7%, respectively. Additionally, we obtain different functional parameters, including the ON-OFF contrast ratio, rise time, fall time, and total footprint, which are measured at 17.47dB, 0.1ps, 0.05ps, and 147µm 2, respectively.

Optical Spectra of a Photonic Crystal Structure with Graphene Layers

Optical Spectra of a Photonic Crystal Structure with Graphene Layers

Spectral Characteristics of a Photonic Crystal Structure with a Monolayer of Metal Nanoparticles

Spectral Characteristics of a Photonic Crystal Structure with a Monolayer of Metal Nanoparticles

Realization of Jackiw–Rebbi zero-energy modes at photonic crystal domain walls: Emergence of polarization-indiscriminate surface states

The Jackiw–Rebbi model is a relativistic quantum model credited with the theoretical predictions of zero-energy bound states and charge fractionalization prior to the discovery of topological insulators and the fractional quantum Hall effect. In this work, we demonstrate a photonic equivalent of the Jackiw–Rebbi model by resorting to photonic crystal band structure engineering. Specifically, our photonic realization employs two spatial inversion symmetric binary photonic crystals exhibiting complementary signs of differential effective mass parameter (δm) for their second bandgaps. Their concatenation manifests a step discontinuity in the spatial profile of the effective mass parameter, forming a domain wall at the photonic crystal interface. Upon analyzing the reflectance spectra of the concatenated photonic crystal structure, we find a midgap surface state localized at this domain wall. Furthermore, much in agreement with the Jackiw–Rebbi zero-energy solution, the materialized photonic surface state also exhibits a zero-energy character in a differential energy space corresponding to the δm parameter, which has been quantified experimentally. Crucially, the conceived zero-energy mode amounts to the observation of a peculiar surface state with polarization-indiscriminate dispersion that can help realize all-angle polarization neutral optics.

Bio‐Inspired Camouflage Skin with Photonic Crystal Structure and Size‐Confinement Effect

AbstractCamouflage skin holds immense potential for a variety of advanced applications, such as artificial intelligence, soft robotics, and flexible/wearable electronics. Currently, most existing materials for constructing camouflage skin are mainly based on inorganic materials with an inverse opal scaffold, which significantly limits their further development because of the poor mechanical properties and environmental instability. Inspired by rana slvaticas, a new type of camouflage skin based on one‐dimentional (1D) photonic crystal (PC) gel is designed and synthesized, which combines the advantages of 1D PC structures with 3D flexible gels in a single skin device. Taking advantage of the unique structures, the resulting camouflage skins demonstrated attractive properties, including excellent mechanical performance, self‐adaptive camouflage capabilities, and long‐term stability in ambient conditions. Specifically, the camouflage skin can quickly recognize and match the background by modulating the optical signals of external stimuli. The synergistic effect of the glycerol, the dodecyl glycerol itaconate (DGI), and the nano‐space structures altogether contribute to the outstanding long‐term environmental stability of the camouflage skin. Overall, by combining the bio‐inspired concept and molecular engineering strategy, camouflage skin based on PC gels is synthesized, which greatly enriched the application and development in the smart skins field.

Development of axion haloscopes for high-mass search at CAPP

The axion offers a well-motivated solution to two fundamental questions in modern physics: the strong CP problem and the dark matter mystery. Cavity haloscopes, exploiting resonant enhancement of photon signals, provide the most sensitive searches for axion dark matter in the microwave region. However, current experimental sensitivities are limited to the O(100)μeV range, while recent theoretical predictions for the axion mass favor up to O(102)μeV, suggesting the need of new experimental approaches that are suitable for higher mass regions. CAPP has developed/proposed several haloscopes effective for high-mass axion searches based on new cavity concepts and practical tuning mechanisms. They are characterized by large detection volumes and/or high quality factors at high frequencies, achieved by partitioning a single cavity into multiple cells, exploiting higher-order resonant modes, and constructing dielectric photonic crystal structures. Improving on the dish antenna haloscope scheme, a horn antenna array has also been proposed for volume-efficient broadband search in the THz region. We review these haloscope designs for sensitive search in the high-mass regions and discuss their impacts on future experiments.

Photonic Crystal Beam Splitter Electrode in Kesterite Tandem Solar Cells: A Numerical Approach

The majority of numerical research on kesterite tandem solar cells has predominantly focused on a two‐terminal (2T) configuration that utilizes an ideal tunnel junction. Herein, the performance of kesterite tandem solar cells by introducing a photonic crystal structure (1DPC) as intermediate layer in both three‐terminal (3T) and four‐terminal (4T) configurations is investigated. The photonic crystal (1DPC) is designed by stacking ITO and SiO2 layers with the terminal layer consisting of NiO. Optical properties of the 1DPC are modeled. This innovative approach offers several advantages. 1) The 1DPC selectively reflects lower wavelengths, effectively enhancing the short‐circuit current density (Jsc) of the top subcell, while the solar irradiance spectrum at higher‐wavelength optimum for the subcell is not affected. 2) The 1DPC serves as an intermediate electrode, needed for the 3T or 4T configuration. 3) Replacing the conventional Mo back contact with a NiO layer significantly boosts the open‐circuit voltage (Voc) of the top subcell. The findings demonstrate that these configurations exhibit higher performance compared to previously reported results. Furthermore, the utilization of 3T and 4T configurations, incorporating the 1DPC as an electrical beam splitter, provides an effective and accurate design compared to the 2T configuration using ideal tunnel junctions.

Double-Layer InSb Photonic Crystal Structure for Enhanced Nonreciprocal OTS and Its Potential in Extending the Measurement Range of Bivariate Sensors

Double-Layer InSb Photonic Crystal Structure for Enhanced Nonreciprocal OTS and Its Potential in Extending the Measurement Range of Bivariate Sensors

Design of all-optical AND gate based on a hybrid photonic crystal and plasmonic structure

Design of all-optical AND gate based on a hybrid photonic crystal and plasmonic structure

Modulation of the emission spectrum of rare-earth ions using inverse-designed photonic crystals cavities.

Rare-earth elements play an indispensable role in the optical communication and laser industries, due to their superior luminescent properties. Nevertheless, the selective enhancement and suppression of different emission bands during energy level transitions for multi-band emitting rare-earth ions presents a significant research challenge, which we aim to address. This study explores the potential of leveraging an inverse-designed dual-cavity photonic crystals structure to manipulate the emission spectrum, thereby facilitating the augmentation or suppression of distinct emission bands. We utilized a convolutional neural network model to establish the relationship between geometric parameters and the local density of states, forecasting the optimal cavity geometry parameters for achieving the desired modulation outcomes. This paper delineates the neural network's generalization capabilities, along with the modulation efficacy of the dual-cavity configuration, both confirmed through numerical validation. Our findings highlight the modulatory capacity of Dy3+ ions, which exhibit three emission spectrum in the visible range, to achieve pure color light emission within the devised cavity structure. Notably, our approach yielded enhancements of up to 2.79-fold and 2.81-fold in pure yellow and red light emissions respectively, compared to free space emissions. The single-sided emission enhancement reaches 16.28-fold for yellow light and 30.79-fold for red light. This emphasizes the transformative potential of this methodology in crafting rare-earth-based luminescent materials with meticulously engineered emission attributes.

Ultra-compact electro-optic phase modulator based on a lithium niobate topological slow light waveguide.

Electro-optic modulators (EOMs) are essential devices of optical communications and quantum computing systems. In particular, ultra-compact EOMs are necessary for highly integrated photonic chips. Thin film lithium niobate materials are a promising platform for designing highly efficient EOMs. However, EOMs based on conventional waveguide structures are at a millimeter scale and challenging to scale down further, greatly hindering the capability of on-chip integration. Here, we design an EOM based on lithium niobate valley photonic crystal (VPC) structures for the first time. Due to the high effective refractive index introduced by the strong slow light effect, the EOM can achieve an ultra-compact size of 4 μm×14 μm with a half-wave voltage of 1.4 V. The EOM has a high transmittance of 0.87 in the 1068 nm because of the unique spin-valley locking effect in VPC structures. The design is fully compatible with current nanofabrication technology and immune to fabrication defects. Therefore, it opens a new possibility in designing lithium niobate electro-optic modulators and will find broad applications in optical communication and quantum photonic devices.

Hypercholesterolemia diagnosis by a biosensor based on photonic crystal PANDA structure

Hypercholesterolemia diagnosis by a biosensor based on photonic crystal PANDA structure

Gamma radiation detector using Cantor quasi-periodic photonic crystal based on porous silicon doped with polymer

The measurement of patients’ dosages of radiation caused by medical diagnostics continues to be challenging. A Cantor sequence photonic crystal structure using porous silicon doped with a polymer of polyvinyl alcohol, carbol fuchsin and crystal violet (DPV) is proposed. The influence rules of geometrical and optical parameters such as the radiation doses, number of periods, porosity of porous layers, incident angle and thickness of layers are investigated using MATLAB based on the transfer matrix method. The transmittance of the Cantor sequence of a defective photonic crystal sensor under different conditions is investigated to select the optimum conditions. The proposed system recorded the accepted sensitivity of 0.265[Formula: see text]nm/Gy, FoM of 6.5[Formula: see text]Gy[Formula: see text], Q of 12,701, RS of [Formula: see text] and LoD of [Formula: see text] for gamma radiation. The suggested detector has simple design, accurate monitoring efficiency and immense potential for gamma radiation sensing.

Analysis of a Modified Y-Branch CWDM Demultiplexer Based on Photonic Crystal Structure

Analysis of a Modified Y-Branch CWDM Demultiplexer Based on Photonic Crystal Structure

Dual-band semi-Dirac cones in two-dimensional photonic crystal and zero-index material

<sec>Semi-Dirac cones, a type of unique dispersion relation, always exhibit a series of interesting transport properties, such as electromagnetic topological transitions and anisotropic electromagnetic transmission. Recently, dual-band semi-Dirac cones have been found in three-dimensional photonic crystals, presenting great potential in electromagnetic wave regulation. However, to the best of our knowledge, there has been no report on dual-band semi-Dirac cones and their applications in two-dimensional photonic crystals, and most of two-dimensional systems have only realized semi-Dirac cones at a single frequency. Therefore, we are to realize dual-band semi-Dirac cones in two-dimensional photonic crystals.</sec><sec>In this work, a type of two-dimensional photonic crystal that comprises a square lattice of elliptical cylinders embedded in air is proposed. By rotating the elliptical cylinders and adjusting their sizes appropriately, accidental degeneracy at two different frequencies is achieved simultaneously in the center of the Brillouin zone. Using <inline-formula><tex-math id="M2">\begin{document}${\boldsymbol{k}} \cdot {\boldsymbol{p}}$\end{document}</tex-math><alternatives><graphic specific-use="online" xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="18-20240800_M2.jpg"/><graphic specific-use="print" xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="18-20240800_M2.png"/></alternatives></inline-formula> perturbation theory, the dispersion relations near the two degenerate points are proved to be nonlinear in one direction, and linear in other directions. These results indicate that the double accidental degenerate points are two semi-Dirac points with different frequencies, and two different semi-Dirac cones, i.e. dual-band semi-Dirac cones, are realized simultaneously in our designed photonic crystal. More interestingly, the dual-band semi-Dirac cones exhibit opposite linear and nonlinear dispersion relation along the major axis and the minor axis of the ellipse, respectively. And our photonic crystal can be equivalent to an impedance-matched double-zero index material in the direction of linear dispersion and a single-zero index material in the direction of nonlinear dispersion, which is demonstrated by the perfect transmission in the straight waveguide and wavefront shaping capabilities of electromagnetic waves. Based on the different properties of the equivalent zero-refractive-indices near the frequencies of two semi-Dirac point, the designed Y-type waveguide can be used to realize frequency separation by leading out the plane waves of different frequencies along different ports. We believe that our work is meaningful in broadening the exploration of the band structures of two-dimensional photonic crystals and providing greater convenience for regulating electromagnetic waves.</sec>

A new magneto-optical phenomenon enhanced by Au nanoparticles on 3D Ni sub-microstructures.

We constructed a bio-structured surface-plasmonic/magneto-optic composite of ferromagnet metal Ni and noble metal Au. It was found that Ni Morpho menelaus (Mm) butterfly wings (BWs) with a natural photonic crystal structure have an apparent enhancement of light reflection under a 0.3 T magnetic field. Additional introduction of discrete Au particles helps further increase this magnetism-induced response. Compared with Mm-Ni-BWs, Mm-Ni-Au30-BWs' reflectance increases 5.3 times at 1944 nm. This investigation helps reveal and understand the effects of new micro-nanostructures on surface plasmon/magneto-optic coupling, benefiting future applications of biology sensors, chemical sensors, photonic chips, electrical communication systems, etc.