Intrinsic Resonance Research Articles

Transition from Phononic to Geometrical Mie Modes Measured in Single Subwavelength Polar Dielectric Spheres

Spherical dielectric resonators are highly attractive for light manipulation, thanks to their intrinsic electric and magnetic resonances. Here, we present measurements of the mid-infrared far-field thermal radiation of single subwavelength dielectric spheres deposited on a gold substrate, of radii ranging from 1 to 2.5 μm, which agree quantitatively with simulated absorption cross sections. For SiO2 microspheres, we evidence the excitation of both surface phonon-polariton (SPhP) modes and geometrical electric and magnetic Mie modes. The transition from a phonon-mode-dominated to a Mie-mode-dominated emission spectrum is observed, with a threshold radius of ∼1.5 μm. We also show that the presence of the metallic substrate augments the computed spheres absorption cross-section due to increased local field enhancement, arising from the near-field interaction of the spheres oscillating charges with their image in the metallic mirror. In contrast, measurements of single subwavelength SPhP-inactive PTFE spheres reveal that the mid-infrared response of such lossy spheres is dominated by their bulk absorption. Our results demonstrate how engineering the geometrical and dielectric properties of subwavelength scatterers can enable the control of thermal emission near room temperature, with exciting perspectives for applications such as radiative cooling.

Abstract 3919: MosaicNeedles: A tool for large-scale proteomics combining antibodies and aptamers

Abstract Proteomics have the potential to transform biomarker discovery, diagnostics, and personalized medicine as it provides functional and actionable information linked to disease phenotypes. However, mass spectrometry (MS) – based proteomics has not been possible at large scale due to limited dynamic range, complex workflow and high experimental cost per sample. Antibody-based methods, although widely used in targeted proteomics for their better sensitivity, have been limited to the profiling of a few hundred selected proteins, partly due to the limited availability of antibody pairs. NanoMosaic has demonstrated antibody-aptamer sandwich assays on the MosaicNeedle࣪ platform. This expands the content size from a few hundred to a few thousand, achievable in one reaction with high sensitivity and specificity and low cross-reactivity. MosaicNeedles࣪ are densely integrated nanoneedle sensors fabricated on a planar substrate. 94,000 sensors with more than 2 billion total nanoneedles can be integrated on to a standard SBS plate, which can also be grouped into 96, 384 or 1536 formats. Each sensor contains an array of nanoneedles, dedicated to detecting one analyte of interest. All nanoneedles comprising the same sensor are functionalized with the same capture antibodies or aptamers. At low analyte concentration, the binding of proteins to the nanoneedles follows a Poisson distribution. Therefore, statistically, no more than one molecule is bound per nanoneedle. A further addition of aptamers or antibodies will form a sandwich complex with the target analyte. Since each of the nanoneedles has an intrinsic optical resonance spectrum and will red-shift as the sandwich complex forms on its surface, the number of analytes can be quantitated by simply counting the number of nanoneedles that display a color change. At high analyte concentration, each nanoneedle has more than one analyte, so the number of analytes can be calculated by averaging the spectrum shifts of all nanoneedles. This combined single molecule counting (digital) and spectrum shift (analog) analysis allows the platform to detect both high abundance and low abundance protein analytes in one reaction. We have demonstrated that the aptamer-antibody assay on the MosaicNeedle࣪ platform achieves better sensitivity than the well-developed antibody-pair assay. It also achieves larger dynamic range and alleviates the antibody cross-reactivity by refining aptamers during the SELEX process. The scalability in manufacturing nanoneedles combined with the low sample requirement and no fluorescent labeling all help to drive down the cost-per-protein to enable large-scale, unbiased proteomics. We envision researchers will use MosaicNeedle࣪ platform for both the upstream target discovery phase and then transfer seamlessly to the downstream validation phase by building customized and targeted panels for proteins of high interest that emerge from the discovery phase. Citation Format: Qimin Quan, Alaina Kaiser, Joshua Ritchey, Joe Wilkinson, John Geanacopoulos, John Boyce. MosaicNeedles: A tool for large-scale proteomics combining antibodies and aptamers [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3919.

Efficient Prevention of Aspergillus flavus Spores Spread in Air Using Plasmonic Ag-AgCl/α-Fe2O3 under Visible Light Irradiation.

Aspergillus flavus is a kind of widespread fungi that can produce carcinogenic, teratogenic, and mutagenic secondary metabolites known as aflatoxins. Aspergillus flavus mainly spread through the means of fungal spores in air, thus preventing the spores spread is an effective strategy to control aflatoxins contamination from source. Herein, a rapid and efficient control way to prevent the spread of Aspergillus flavus spores in air was demonstrated. Ag-AgCl nanoparticles were combined with tetrahedral α-Fe2O3 to form plasmonic composites that presented 93.65 ± 1.53% prevention rate of Aspergillus flavus spores under 50 min visible light irradiation. The efficient activity was attributed to the synergy effect of Ag including intrinsic disinfection, electron sink, and localized surface plasmon resonance effect, which were proven by photoelectric characterization, density functional theory, and finite difference time domain methods. The calculated work functions of α-Fe2O3, Ag, and AgCl were 3.71, 4.52, and 5.38 eV, respectively, which could accelerate photoinduced carrier transfer through Ag during photoreaction. Moreover, it was found that the intrinsic disinfection of Ag and hydroxyl radical from photocatalytic reaction were the main factors to the prevention of Aspergillus flavus spores, which resulted in the destruction of spore structure and the leakage of intracellular protein with 62.15 ± 2.63 μg mL-1. Most important, it was proven that the composites also showed high activity (90.52 ± 1.26%) to prevent Aspergillus flavus spore spread in the storage process of peanuts. These findings not only provided useful information for an efficient and potential strategy to prevent Aspergillus flavus contamination but also could be as a reference in toxic fungi control.

Proteogenomic detection of circulating biomarkers for clinical oncology.

e15010 Background: Circulating biomarkers have the potential to detect cancer in its earliest stages and monitor patients in remission. The integration of proteogenomics in circulating biomarkers may transform the molecular diagnostics of cancer and accelerate basic and clinical oncology research. Proteomics bridges the gaps of functional information lost due to post-transcriptional and post-translational modifications in a genomic approach. A recent study showed that adding just 8 protein biomarkers to a panel of circulating DNA biomarkers increased the diagnostic accuracy up to 98% sensitivity and 99% specificity. However, the proteogenomic approach normally requires the use of multiple different assay technologies and laboratory workflows, including mass spectrometry. Methods: MosaicNeedles are densely integrated nanoneedle sensors fabricated on a planar substrate that integrates proteogenomic analysis in one platform. 94,000 sensors with more than 2 billion total nanoneedles can be integrated on to a standard SBS plate, which can be configured into 96, 384 or 1536 well format. Each sensor contains an array of nanoneedles, dedicated to detecting one analyte of interest. All nanoneedles comprising the same sensor are functionalized with the same capture probes. The capture probe can be either an antibody for protein detection or an oligonucleotide with a specific target sequence to a DNA fragment, mRNA, or miRNA of interest. Results: At low analyte concentration, the binding of proteins to the nanoneedles follows a Poisson distribution. Therefore, statistically, no more than one molecule is bound per nanoneedle. A further addition of aptamers or antibodies will form a sandwich complex with the target analyte. Since each of the nanoneedles has an intrinsic optical resonance spectrum and will red-shift as the sandwich complex forms on its surface, the number of analytes can be quantitated by simply counting the number of nanoneedles that display a color change. At high analyte concentration, each nanoneedle has more than one analyte, so the number of analytes can be calculated by averaging the spectrum shifts of all nanoneedles. This combined single molecule counting (digital) and spectrum shift (analog) analysis allows the platform to detect both high abundance and low abundance protein analytes in one reaction. A 10,000-plex study can be achieved with a total of 2.5 billion nanoneedles on a 50mm by 50mm consumable. In this consumable, a 2,000-plex proteome and 8,000 cell-free DNA fragments can be detected. Conclusions: A full proteogenomic quantification can be performed on the NanoMosaic platform in one reaction with high sensitivity and large dynamic range. It simplifies the workflow and allows users to integrate proteomic and genomic information to discover new circulating biomarkers.

Partial coherence and amplified internal energy when thermal radiation is sourced within matter

Photons excited into ground state modes at finite temperature display partitioning among photon phases, lifetimes and distances travelled since creation. These distributions set the distance from an interface a created photon has some chance of emission. Excited photons have phase velocity set by their mode’s propagation index n which sets mode density then internal energy contribution. All photons that strike an interface obliquely if emitted are refracted, and their exit intensities are irreversible except when weak internal attenuation occurs. Attenuation index k near zero degrees is small, so reversibility is approximate. As temperature rises refraction of exiting photons varies. Total emission remains reversible after transitioning through a nonequilibrium state with no other heat inputs. In equilibrium the densities of excitations that create and annihilate photons are in balance with photon densities, and emissivity dependent on n, k, temperature, and internal incident direction. Exit intensities from pure water and crystalline silica are modelled. They contain strong resonant intensities, and match data accurately. Intrinsic resonances formed within liquids and compounds are due to photon modes hybridising with localized excitations, including molecular oscillations and the anharmonic component of lattice distortions. They explain the many resonant spectral intensities seen in remote sensing. Each hybrid oscillator is a photonic virtual bound state whose energy fluctuates between levels separated by hf. Other features addressed are radiance when solid angle changes at exit, anomalous refraction, thermal recycling of internally reflected photons, fluxes within multilayers, and enhanced internal heat flux from phonon drag by photon density gradients under an external temperature gradient.

Improving broadband absorption and transparent properties for microwave metamaterial via stimulating bimodal effect with induced water substrate

In this paper, a frequency selective microwave absorber is designed and demonstrated with water as the substrate layer, which realizes >90% absorption in the frequency range of 7.3–20 GHz and 73.6% light transparent in the spectrum range of 400–800 nm. The improved absorption is believed to be attributed to the synergy between the intrinsic resonance of the ITO metasurface and the new resonance excited by the substrate water layer. Particularly, the light transparence of the absorber is improved with the introduced water layer. Therefore, the proposed absorber shows excellent comprehensive performances for high optical transparent microwave broadband absorbers.

Possible solution for the integer resonance crossing problem of GeV-class isochronous Fixed-Field Alternating Gradient accelerators

Fixed-Field Alternating Gradient accelerators (FFAG, also known as FFA) are promising candidates for next-generation GeV-class proton driver with average beam power of several megawatts. In isochronous accelerators, radial tunes are approximately increasing with beam energy in a linear way, and thus the integer resonance crossing problem becomes the major bottleneck of GeV-class isochronous FFAG design. In 2019, China Institute of Atomic Energy (CIAE) proposed an isochronous FFAG conceptual design with capability of producing 2GeV/6MW continuous wave (CW) proton beam. However, this conceptual design shows that the beam size is blown up at high energy region due to the third harmonic magnetic field caused by imperfections. The reason is that the integer resonance vr=3 causes a large coherent oscillation, and this large amplitude is not compatible with the following third order intrinsic resonance 3vr=10. In order to correct the large coherent motion before reaching the 3vr=10 resonance, we propose an idea of integer resonance suppressor (IRS) which intentionally introduces the third harmonic magnetic field. Our calculation shows that third harmonic field of 10Gs is acceptable with proper IRS settings, meaning that the requirements of magnet manufacture and installation can be relaxed. The increased imperfection tolerances will make magnet manufacture and installation much easier.

Thermal Switching of Near-Field Radiative Heat Transfer Between Nanoparticles via Multilayered Surface Modes

We theoretically demonstrate near-field radiative thermal switching between two nanoparticles located above a multilayered slab. We propose a multilayered structure composed of $\mathrm{Si}\mathrm{C}$ and the phase transition material ${\mathrm{VO}}_{2}$. The high tunability of the multilayered structure enables the active modulation of surface polaritons when combined with the phase transition feature of ${\mathrm{VO}}_{2}$, overcoming the intrinsic resonance of the thermal radiation of ${\mathrm{VO}}_{2}$. Utilizing this feature, the surface polaritons enormously excited at the particle's resonant frequency above the multilayer can be switched on or off, resulting in the efficient modulation of heat flux between nanoparticles. The effects of interparticle distance and multilayer parameters on thermal switching ratios are investigated. We demonstrate that the multilayer with metallic ${\mathrm{VO}}_{2}$ can significantly inhibit the heat flux between particles as a result of the destructive interference between direct and reflected waves. The excited surface modes above the multilayer with insulating ${\mathrm{VO}}_{2}$ can still improve the heat flux between nanoparticles, resulting in a thermal switching ratio of ${10}^{\ensuremath{-}5}$ at the particle resonant frequency at a large interparticle distance.

Highly sensitive methane detection based on light-induced thermoelastic spectroscopy with a 2.33 µm diode laser and adaptive Savitzky-Golay filtering.

In this manuscript, a highly sensitive methane (CH4) sensor based on light-induced thermoelastic spectroscopy (LITES) using a 2.33 µm diode laser with high power is demonstrated for the first time. A quartz tuning fork (QTF) with an intrinsic resonance frequency of 32.768kHz was used to detect the light-induced thermoelastic signal. A Herriot multi-pass cell with an effective optical path of 10 m was adopted to increase the laser absorption. The laser wavelength modulation depth and concentration response of this CH4-LITES sensor were investigated. The sensor showed excellent long term stability when Allan deviation analysis was performed. An adaptive Savitzky-Golay (S-G) filtering algorithm with χ2 statistical criterion was firstly introduced to the LITES technique. The SNR of this CH4-LITES sensor was improved by a factor of 2.35 and the minimum detection limit (MDL) with an integration time of 0.1 s was optimized to 0.5 ppm. This reported CH4-LITES sensor with sub ppm-level detection ability is of great value in applications such as environmental monitoring and industrial safety.

Piezo2-peripheral baroreceptor channel expressed in select neurons of the mouse brain: a putative mechanism for synchronizing neural networks by transducing intracranial pressure pulses.

Here we use immunohistochemistry to examine the expression of Piezo2 in neurons of the mouse dorsal root ganglia and brain. Whereas Piezo2 is expressed in the large majority (≥ 90%) of dorsal root ganglia neurons, Piezo2 expression is restricted to select neuron types in specific brain regions, including neocortical and hippocampal pyramidal neurons, cerebellar Purkinje cells and mitral cells of the olfactory bulb. Given the well-established role of Piezo2 as a low-threshold pressure sensor (i.e., ≤5 mmHg) in peripheral mechanosensation, including the regulation of breathing and blood pressure, its expression in central neurons has interesting implications. In particular, we hypothesize that Piezo2 provides neurons with an intrinsic resonance that promotes their entrainment by the normal intracranial pressure pulses (~5 mmHg) associated with breathing and cardiac cycles. The pressure-induced change in neural activity need only be very subtle to increase, for example, the robustness of respiration-entrained oscillations reported previously in widely distributed neuronal networks in both rodent and human brains. This idea of a "global brain rhythm" first arose from the effect of nasal airflow in activating mechanosensitive olfactory sensory neurons, which then synaptically entrain mitral cells within the olfactory bulb and through their projections, neural networks in other brain regions, including the hippocampus and neocortex. Our proposed, non-synaptic, intrinsic mechanism, where Piezo2 tracks the highly predictable and "metronome-like" intracranial pressure pulses-to date generally considered epiphenomena-would have the advantage that a physical force rapidly transmitted throughout the brain also contributes to this synchronization.

Local Spatial Polarization Induced Efficient Charge Separation of Squaraine‐Linked COF for Enhanced Photocatalytic Performance

AbstractThe efficiencies of semiconductor photocatalysis are always severely restricted by the rapid recombination of charge carriers in the bulk phase, while local polarization is an efficient scenario to conquer the above issue to boost the photocatalytic performance. Here, as a proof‐of‐concept demonstration, local charge polarization induced by the intrinsic zwitterionic resonance structure of photocatalysts is reported. A novel squaraine‐based covalent organic framework (SQ‐COF‐1) photocatalyst with an interesting zwitterionic resonance structure is creatively developed. Meanwhile, the comparison samples (SQ‐COF‐2 and PDA‐COF) based on similar COF structure with tunable local polarity are accordingly designed and prepared. The local charge polarization generated from the zwitterionic resonance structure profoundly redistributes and separates the charge carriers, as evidenced by experimental and theoretical results collectively. Benefiting by the largest local polarization, SQ‐COF‐1 exhibits superior visible‐light‐driven photocatalytic activities than SQ‐COF‐2, PDA‐COF, and commonly used polymeric carbon nitride photocatalyst. This work presents a local charge polarization protocol for engineering charge behavior to promote photocatalysis, which shows great promise for the future design of high‐performance photocatalytic materials.

Resonance analysis using a high frequency simulation method for dc-SQUID amplifiers

We performed high-frequency simulation to optimize the geometric size of dc-SQUID amplifiers and to remove their intrinsic resonance characteristics from the operating range. The aim is to eliminate distortions in the IVΦ characteristics that ensures low noise and stable operation over a large range of bias current. With this method, we designed and fabricated a dc-SQUID amplifier with two series-connected octagonal loops to achieve a robust operating performance. The measured results not only show smooth IVΦ characteristics without any distortion, but also demonstrate that the swing voltage is much larger than the corresponding voltage realized without this method at the same bias current. In addition, the white flux noise level as low as 1.7 μΦ0/√Hz was achieved at 0.1 K corresponding to a low current noise level of 15 pA/√Hz.

Optical properties and thermal stability of AlCrON-based multilayer solar selective absorbing coating for high temperature applications

A multilayer coating comprising Cr as IR reflector, alternative AlCrN/AlCrON as absorber and AlCrO as anti-reflective layer has been designed and deposited on stainless-steel substrate by cathodic arc ion plating. It was found that the selectivity (α/ε) of multilayer coating was increased from 0.919/0.128 to 0.928/0.105 after annealing at 550 °C in vacuum for 2000 h. Microstructural analysis revealed the formation of nanocrystalline/amorphous composite structures in the AlCrN/AlCrON absorbers and AlCrO anti-reflective layer, which was beneficial to improve the thermal tolerance of the multilayer coating by restraining nanoparticles agglomeration and interface degradation. The enhancement in selectivity after vacuum annealing was ascribed to the partial recrystallization of the amorphous matrices, resulting in the formation of nitride nanoparticles, which can promote the intrinsic absorption due to the increase of optical path. However, the multilayer coating destabilized when annealed at 550 °C in air for 2000 h. Based on the microstructural characterization, the corresponding failure mechanism was attributed to the element migration between adjacent sublayers, structural relaxation of the amorphous matrix, and surface solute atoms segregation induced oxidation and coalescence of nanoparticles, which degenerated the intrinsic absorption and localized surface plasmon resonance of nanoparticles in AlCrN and AlCrON absorbers.

Highly Directive All-Dielectric Nanoantenna

A highly directive dielectric nanoantenna in an integrated chip may enable faster communication as their low losses and small size overcome the limitation of temperature enhancement and low data transfer rate. We optimize nanoantenna consist of Si-nanoblock in the near-infrared region to efficiently transfer a point dipole light to a highly directive light in the far-field region. We engineer the intrinsic electric and magnetic resonances of a Si-block nanoantenna by modifying and reducing its geometrical symmetry. We realize a pronounced enhancement of directivity by systematically inducing perturbation in the Silicon block so that both its reflection and rotational symmetries are broken. Finally, we retain the traditional method to increase resonance’s coupling to outer space by introducing substrate with an increasing refractive index. We find that the directivity has boosted rapidly.

Graft-Then-Shrink: Simultaneous Generation of Antifouling Polymeric Interfaces and Localized Surface Plasmon Resonance Biosensors.

Antifouling polymer coatings that are simple to manufacture are crucial for the performance of medical devices such as biosensors. "Grafting-to", a simple technique where presynthesized polymers are immobilized onto surfaces, is commonly employed but suffers from nonideal polymer packing leading to increased biofouling. Herein, we present a material prepared via the grafting-to method with improved antifouling surface properties and intrinsic localized surface plasmon resonance (LSPR) sensor capabilities. A new substrate shrinking fabrication method, Graft-then-Shrink, improved the antifouling properties of polymer-coated Au surfaces by altering graft-to polymer packing while simultaneously generating wrinkled Au structures for LSPR biosensing. Thiol-terminated, antifouling, hydrophilic polymers were grafted to Au-coated prestressed polystyrene (PS) followed by shrinking upon heating above the PS glass transition temperature. Interestingly, the polymer molecular weight and hydration influenced Au wrinkling patterns. Compared to Shrink-then-Graft controls, where polymers are immobilized post shrinking, Graft-then-Shrink increased the polymer content by 76% in defined footprints and improved the antifouling properties as demonstrated by 84 and 72% reduction in macrophage adhesion and protein adsorption, respectively. Wrinkled Au LSPR sensors had sensitivities of ∼200-1000 Δλ/ΔRIU, comparing favorably to commercial LSPR sensors, and detected biotin-avidin and desthiobiotin-avidin complexation in a concentration-dependent manner using a standard plate reader and a 96-well format.

Quantum chemical insight into the effects of the local electron environment on T2*-based MRI

T2* relaxation is an intrinsic magnetic resonance imaging (MRI) parameter that is sensitive to local magnetic field inhomogeneities created by the deposition of endogenous paramagnetic material (e.g. iron). Recent studies suggest that T2* mapping is sensitive to iron oxidation state. In this study, we evaluate the spin state-dependence of T2* relaxation using T2* mapping. We experimentally tested this physical principle using a series of phantom experiments showing that T2* relaxation times are directly proportional to the spin magnetic moment of different transition metals along with their associated magnetic susceptibility. We previously showed that T2* relaxation time can detect the oxidation of Fe2+. In this paper, we demonstrate that T2* relaxation times are significantly longer for the diamagnetic, d10 metal Ga3+, compared to the paramagnetic, d5 metal Fe3+. We also show in a cell culture model that cells supplemented with Ga3+ (S = 0) have a significantly longer relaxation time compared to cells supplemented with Fe3+ (S = 5/2). These data support the hypothesis that dipole–dipole interactions between protons and electrons are driven by the strength of the electron spin magnetic moment in the surrounding environment giving rise to T2* relaxation.

Spontaneous Light Emission Assisted by Mie Resonances in Diamond Nanoparticles.

Spontaneous light emission is known to be affected by the local density of states and enhanced when coupled to a resonant cavity. Here, we report on an experimental study of silicon-vacancy (SiV) color center fluorescence and spontaneous Raman scattering from subwavelength diamond particles supporting low-order Mie resonances in the visible range. For the first time to our knowledge, we have measured the size dependences of the SiV fluorescence emission rate and the Raman scattering intensity from individual diamond particles in the range from 200 to 450 nm. The obtained dependences reveal a sequence of peaks, which we explicitly associate with specific multipole resonances. The results are in agreement with our theoretical analysis and highlight the potential of intrinsic optical resonances for developing nanodiamond-based lasers and single-photon sources.

Cavity and ground effects on a superconducting microstrip resonator

Superconducting planar-transmission-line resonators play an increasingly important role in applications such as astronomical detection and circuit quantum electrodynamics. When measuring the transmission response of an array of resonators, however, one often observes some spurious resonances besides the intrinsic ones. In this letter, the effect of the cavity accommodating a half-wavelength superconducting microstrip resonator is investigated. An attenuation pole associated with the intrinsic resonance of the half-wavelength resonator is clearly observed and found to be resulted from the mutual coupling between the microstrip resonator and the cavity. In addition, it is demonstrated that adding a superconducting ground layer for such a microstrip resonator can avoid the frequency shift owing to an ever-present thin air gap between the microstrip resonator and the cavity and can also improve the Q factor of the microstrip resonator.

From signal-based to comprehensive magnetic resonance imaging

We present and evaluate a new insight into magnetic resonance imaging (MRI). It is based on the algebraic description of the magnetization during the transient response—including intrinsic magnetic resonance parameters such as longitudinal and transverse relaxation times (T1, T2) and proton density (PD) and experimental conditions such as radiofrequency field (B1) and constant/homogeneous magnetic field (B0) from associated scanners. We exploit the correspondence among three different elements: the signal evolution as a result of a repetitive sequence of blocks of radiofrequency excitation pulses and encoding gradients, the continuous Bloch equations and the mathematical description of a sequence as a linear system. This approach simultaneously provides, in a single measurement, all quantitative parameters of interest as well as associated system imperfections. Finally, we demonstrate the in-vivo applicability of the new concept on a clinical MRI scanner.

An Accurate Integral Equation Formulation to Scattering of Periodic Grating Structures

Broadband wave transmission grating structures have potentials in many engineering applications. Theoretical predictions of the transmission spectra and near field characteristics of such structures are crucial for the understanding and design of wave functional gratings. However, accurate theoretical modeling of the wave interactions with such periodic grating structures turns out to be difficult, especially at near grazing incidence angles. In this paper, an efficient and accurate method to solve the scattering of periodic grating structures is proposed based upon integral equation formulations utilizing periodic lattice Green's functions. The method of moments is used to discretize the integral equation with the pulse basis function and the point matching scheme. The imaginary wavenumber extraction technique and the integral transformation approach are combined to efficiently and accurately evaluate the period Green's function. Meanwhile, an over-determined testing scheme on the integral equation is devised to overcome the intrinsic internal resonance of surface integral equations. Such strategy has significantly improved the numerical accuracy of the proposed approach. Calculation results are compared with Comsol simulations for various scenarios, and the proposed approach is found to be predicting physically sound results when Comsol fails at certain frequencies and incident angles. The proposed method is applicable to grating periodic structures of various shapes and it provides a useful reference and tool for researchers and designers.