This PDF file contains the front matter associated with SPIE Proceedings Volume 13109, including the Title Page, Copyright information, Table of Contents, and Conference Committee information.

Monolayers with closely packed molecules of amphiphilic EuTTA deposited on plasmonic metal demonstrate bright luminescence in contrast with diluted systems and theoretical predictions of full quenching. In order to better understand the role of intermolecular interactions and surface plasmons, we study the spontaneous emission in EuTTA ultra-thin films in dielectric and plasmonic environment. The emission kinetics in systems with closely packed emitters strongly differs from that in diluted emitters. The kinetics and spectra are very sensitive to the environment. Using multilayered structures, we were able to enhance the magnetic to electric dipole transition branching ratio by more than order of magnitude.

One-dimensional photonic crystals are commonly used as high-reflectivity mirrors, Bragg gratings, or for constructing vertical-cavity surface-emitting lasers (VCSELs). By extending periodicity to the spatiotemporal domain, spatiotemporal photonic crystals (STPCs) have enabled new methods of wave manipulation, supporting spatially decaying and temporally growing eigenstates. However, their scattering characteristics and precise gain control remain underexplored. Additionally, these non-Hermitian systems, which rely on parametric processes, are expected to exhibit distinct propagation phenomena. In this study, we constructed STPCs by applying sinusoidal perturbations in both space and time. Our findings reveal that introducing temporal perturbations can simultaneously induce the transitions of photonic bandgap-type and spontaneous PT-symmetry breaking. Moreover, the coherent effects between spatial and temporal perturbations can manipulate gain, enabling tunable devices such as cloaking-amplifiers.

We present an analytical model for Förster resonance energy transfer between donors and acceptors in the presence of a metal surface. We find that energy transfer to the metal results in a reduction of the Förster radius, leading to a suppression of concentration quenching for high molecule concentrations.

Significant photovoltages are induced by laser pulses in permalloy and permalloy-gold structures. The electric effects are maximized at the surface plasmon polariton conditions and depend on magnetic field with characteristic hysteresis. Both magneto-dependent and magnetically independent responses can be tuned with the structure geometry and composition.

This work shows the realization of highly efficient real-time ultraviolet photodetectors using the high band gap semiconductor amorphous indium gallium zinc oxide (a-IGZO). The presented phototransistors are characterized at room temperature with a continuous-wave laser at 226 nm. The characterization includes the detection efficiency (responsivity R) and the response time t_R. Spatially resolved measurements are enabled by the configuration of an active-matrix sensor array. Necessary switching transistors are produced simultaneously to the single-gate thin-film transistors acting as the photosensors. The functionality of the on-glass ultraviolet photosensor array is demonstrated by the determination of the beam waist of the 226nm laser.

We demonstrate Ge-on-Si avalanche photodiodes based on a separate absorption, charge, and multiplication structure using a novel double mesa structure. This double mesa structure effectively confines the electric field inside the diode, as confirmed through simulation data. This leads to a reduced contribution of charge carriers from interface states at the etched sidewalls to the dark current. The diodes exhibit a dark current reduction by a factor of 7 compared to a standard single mesa structure, while the optical properties remain unchanged. At a wavelength of 1310 nm, a maximum optical responsivity of 10.1 A/W, corresponding to a gain of 46, is achieved. Temperature-dependent dark current measurements showed an increase of the underlying activation energy from 0.13 eV to 0.28 eV. This results to a dark current of 0.14 nA at a temperature of 170 K and a bias voltage of 95 % V_BD, which is approximately 100 times smaller than that of the single mesa APDs at 12.7 nA.

We demonstrate an in situ, non-invasive measurement method to ensure stable manufacturing and quality control of integrated waveguides. This method assumes that the scattered light from a waveguide is proportional to the propagating light inside the waveguide. Consequently, we can estimate the waveguide losses by measuring the scattered light along the waveguide. We compare this newly demonstrated measurement method with state-of-the-art methods, including Fabry-Perot interferometry, Mach-Zehnder Interferometry, ring resonator interferometry, and the cut-back method. To validate our measurement method’s working principle, we fabricated multiple amorphous silicon waveguides and characterized them using both, the presented and the cut-back method. Both methods yielded comparable results, indicating losses of around 1 dB/cm. For further investigation, multiple measurements of the same sample were conducted, resulting in a standard deviation of 0.29 dB/cm to 0.60 dB/cm. These initial standard deviations are sufficient to verify the presented measurement method. However, we want to emphasize that the main source of these deviations is due to the used measurement setup, indicating that the method has potential for improvement. Nevertheless, we have demonstrated that an in situ, non-invasive measurement of integrated waveguide losses is possible.

This paper reports on SiGeSn/GeSn multi-quantum-well microdisk lasers. The fabrication of the devices includes a selective under-etching step, which enhances the guiding of the whispering gallery modes inside the cavity. Lasing occurs under different electrical pumping conditions with a very low threshold current and for long, quasi-continuous wave pulses compared to previously reported GeSn-based microdisk lasers. Furthermore, the lasing threshold current is reduced by a factor of ten compared to similar double-heterostructure devices.

Laser-based 3-D nanoprinting exemplified by two photon polymerization (TPP) has emerged as a practical route for additive manufacturing of sub-wavelength scale structures with broad applications in photonic packaging, nanofluidics, nanoelectromechanical systems, drug delivery, tissue engineering, and beyond. Conventional TPP relies on compound refractive lenses for light focusing. Here we present a novel alternative approach leveraging optical metalenses as the light manipulation element for versatile TPP fabrication. Using an inverse design algorithm, we show that the point spread function (PSF) of the metalens can be custom tailored to realize a variety of TPP writing modes, enabling fabrication of unconventional geometries difficult to process with traditional TPP. We demonstrated integration of metalenses with both commercial and home-built TPP systems, and experimentally implemented TPP to writing of 3-D polymer microstructures.

We demonstrate an optical method for sensitivity enhancement for LC resonant MM’s, using meta-plate which act as plasmonic enhancer by increasing the electric field concentration in the active area of the metasurface. This makes the MM resonance ultra-sensitive to the tiny changes of particle size/concentration under test spread on the metasurface, contributing to enhanced spectral shift (ΔF). The meta-plate also makes the Si substrate optically lossless and transparent in THz, enabling the full effect of MM resonance without any substrate losses in the transmission spectra. This work also demonstrates an extended concept of de-coupling MM-resonance from the substrate’s Fabry-Pérot (FP) oscillations by de-trapping of the THz radiation from the MM substrate, resulting in the improved quality-factor of the MM resonance and overall plasmonic enhancement on the metasurface. The plasmonic enhancer meta-plate increases the ΔF by eight-fold compared to MM’s fabricated on conventional Si substrates.

In previous work, we have introduced an analytical approach that utilizes the dispersion relation for an infinite periodic multilayer structure to predict the performance of finite multilayer structures. We have validated the accuracy of our predictions by demonstrating numerical agreement with other established simulation methods, such as the transfer matrix method, and through experimental confirmation. In this work, we employ dispersion relations to first illustrate that metallo-dielectric structures, as opposed to multilayer dielectric-dielectric structures, can efficiently yield a sharp-edge transmittance spectrum profile, with control over both sides of the bandpass cutoff edges. Our approach also enables the calculation of effective permittivity without relying on traditional homogenization techniques. Next, utilizing the concept of effective permittivity, we illustrate that increasing the thickness of specific dielectric layers within MD structures leads to narrower passbands without significant loss in transmission, demonstrating the potential of this approach for engineering the transmittance spectrum of bandpass filters in the visible and near-IR regions. The capability to achieve a sharp-edge filter with a limited number of layers further underscores the cost-effectiveness of such bandpass filters.

Perovskite quantum dots (PQDs) have a tunable emission wavelength by halide anions, as well as excellent blue light absorption, a very narrow full width at half maximum (FWHM), high color purity, and a wide color gamut, making them suitable for replacing traditional phosphors as backlight sources for white light emitting diodes (WLEDs). However, their practical application is limited by surface defects, poor stability, and the presence of heavy metals "lead (Pb)". This study prepared using the thermal injection method to reduce the Pb content through partial replacement with tin (Sn), Additionally, (3-Aminopropyl)triethoxysilane (APTES) was used to coating the perovskite quantum dots with SiO2,to enhance their stability. It was observed that the relative QY was extremely high, reaching up to 198%, with a Sn0.2-A (compared to 59% in literature). When adjusting different Pb-Sn ratios. After a period of time, the emission wavelength shifts by approximately 3 nm for Sn0.2-A and 1 nm for Sn0.5-A. Notably, the luminescence efficiency increases 1.7 times after two months. Both Sn0-A and Sn0.2-A maintain stable full-width at halfmaximum and improve efficiency (up to 1.4 times) after two months. Continuous irradiation for 60 minutes further enhances the efficiency of Sn0.2-A by 1.5 times. Therefore, tin-doped, silica-coated perovskite quantum dots effectively improve relative quantum efficiency and stability, reduce lead content, and present a more sustainable option for future market applications.

In recent years, research in optics and photonics produced many forms of structured light for different applications, such as optical trapping, telecommunication, and imaging. Generating such beams usually requires challenging control of phase, amplitude, and polarization, and often more than one phase plate is needed. Mounting such optical elements leads to lengthy alignment procedures, worsened by tight tolerances and complex beam shapes. Here we present a method for fabricating two aligned metalenses on the two surfaces of a substrate, halving therefore the degrees of freedom for alignment. Such method is shown to work for a device capable of multiplying the topological charge of an OAM beam.

Large-area and transparent all-dielectric metasurfaces supporting photonic bound states in the continuum (BICs) offer several inherent advantages for highly sensitive biosensing applications. A BIC represents a unique mode within the energy spectrum of free-space waves that remains uncoupled with free-space radiation, resulting in a divergent radiative Q-factor and a topological singularity in reciprocal space. In this study, the synergistic combination of photonic crystal slabs (PhCS) supporting bound states in the continuum (BIC) with aptamers and molecularly imprinted polymers (MIPs) offers a groundbreaking approach to achieving ultrahigh sensitivity in detecting mycotoxins in wine and cytokines in artificial saliva. Mycotoxins, toxins produced by certain fungi, pose significant health risks when present in food and beverages like wine. Our research endeavors represent a significant step forward in the field of biosensing, offering a pathway toward the development of versatile, efficient, and reliable sensing platforms with broad applications across scientific, industrial, and societal domains.

We present breathalyzer-based prompt screening technology that can detect and screen multiple respiratory diseases using exhaled breath of a patient, collected on an LC resonant metasurface, demonstrating a spectral red-shift (ΔF). We categorized ΔF for multiple respiratory diseases, which do not overlap. This was physically possible by removing the constraint of detection limit in metamaterials, along with significant sensitivity enhancement physics. This work opens a whole new opportunity to detect and screen multiple lung and breath diseases with one simple and prompt breath test, owing to the multifold sensitivity enhancement physics.

Refractory materials, known for their exceptional thermal stability and robustness in extreme high-temperature conditions, have gained attention in recent years. These materials, including high-melting-point metals, such as titanium, tungsten, chromium, molybdenum, and tantalum, are ideal for applications demanding high-temperature resistance and durability. Here, we present the design of polyatomic refractory metastructures capable of achieving perfect absorptivity as well as near-unity emissivity. We design arrays of clustered refractory-metal nanodisks (tungsten and titanium) coupled to a same-metal backplane with dielectric spacers between the nanodisks and the backplane. Similarly, the spacer is made of refractory materials, silicon nitride and titania, respectively. By tuning the thickness of this spacer, our polyatomic metastructures achieve near-perfect absorptivity and nearunity emissivity across visible and near-infrared spectral ranges (0.4−2 μm). This work highlights the potential of refractory materials for high-performance absorbers and thermal emitters that are capable of withstanding extreme temperatures without compromising performance, thus paving the way for advancements in energy applications and high-temperature sensing.

In the realm of metamaterial research, the exploration of random structures presents an innovative path less traveled, compared to the conventional focus on periodic designs. Our study introduces a novel framework for generating random metamaterials using graph algorithms, which ensures connectivity and adaptability across a multitude of base shapes, such as cylinders, triangles, pyramids, and cubes. This flexibility enables the application of our designs across various domains, allowing for the investigation of properties including stiffness, density, and acoustic impedance. By leveraging graph algorithms in our framework, data representation and manipulation become more intuitive and efficient, facilitating the design process. Our approach demonstrates significant versatility in manipulating the macroscale and microscale elements of the designs, providing a tailored fit for specific applications. We present a series of designs, showcasing the ability to control and predict the material’s behavior under different conditions. The designs can be effectively implemented across various fields and subjected to multiple analytical studies, encompassing static, dynamic, and eigenfrequency assessments. Properties such as impedance, stiffness, density, and more can be explored, opening the door to a wide array of applications and potential innovations in metamaterial research. We illustrate the computational results for stiffness and acoustic impedance, highlighting the method’s efficacy through examples ranging from rod-based to cube-based designs. This framework not only paves the way for advancements in metamaterial research but also opens up new possibilities for innovation in fields requiring customized material properties.

Dynamic electromagnetic structures, which vary in both space and time, enable unique operational regimes and effects unattainable in static systems due to modal orthogonality constraints. This paper presents a theoretical framework for intermodal energy transfer in time-varying plasmonic structures. By identifying a suitable mechanism for permittivity modulation, we develop a time-domain formalism to analyze the evolution of the dielectric polarization density in the system. Through a perturbative approach, we derive closed-form solutions that describe the energy transfer between a directly excited dipolar mode and a higher-order subradiant mode. We also demonstrate that the modal amplitudes reach a steady state under optimal modulation conditions, which maximize the amplitude of the high-order mode. Finally, we propose a coherent control strategy to enhance the conversion efficiency to higher-order modes.

Over the past decade, sub-wavelength diffractive optics has emerged as a promising field of research, offering attractive optical characteristics that allow for the manipulation of the amplitude and phase of incident light on flat surfaces. In particular, metalenses have shown strong potential to replace bulk refractive optical elements with ultra-thin planar platforms. In this study, we present a comparative analysis of wavefront aberration between sub-wavelength, nano-sized dielectric metalenses and commercial plano-convex (PCX) lenses at an infrared (IR) wavelength of 1,550 nm. We developed an off-axis interferometry system to observe the point-spread function (PSF) at the focal plane from phase-resolved interference patterns. The phase distribution across the wavefront was observed and calculated using Zernike polynomials. Additionally, we measured the focal spot size, modulation-transfer function (MTF), and Strehl ratio. Through this analysis, we found that the metalenses demonstrate diffraction-limited characteristics and are strongly competitive or even superior to the commercial PCX lenses in most metrics under the designed monochromatic wavelength.

Artificial neural networks (ANNs) are known to be a versatile tool for device optimization. This work proposes a method to optimize a polarization converter composed of T-shaped periodic resonators, inclined at 45 deg using an ANN. The result is compared with previous work conducted using CST simulation, demonstrating broadband and wide-angle reflective linear polarization conversion. Employing an ANN resulted to improved performance metrics, leading to increased fractional bandwidth of 7.6% for normal incident and 9.8% for 45° incident angle. The neural network achieved a mean square error (MSE) as low as 5.78 × 10⁻⁵, indicating high accuracy. This approach demonstrates the efficiency of ANNs in designing metasurfaces for a wide range of applications.

The realization of high Q EIT metasurface generally relies on the high degree of structural asymmetry by positional displacement of optically resonant structures. Here we demonstrate a high quality EIT metasurface without any displacement of constituent resonator elements.

The measurement of the concentration of nitrates in different solutions is of interest in industrial and biomedical applications. Due to this, it is proposed to work with resonant structures manufactured with microstrip technology which were designed as dielectric permittivity sensors. These devices depend on changes in the dielectric properties of the medium, so they can detect variations in the concentration of nitrates. Depending on the dielectric properties of the sample, the electrical response will be such that changes in the response can be related to variations in the percentage content of nitrates in the measured solutions. The increase in the dissolution of calcium, magnesium and potassium nitrates in water shows a clear and notable change in the resonance frequency with which it is possible to identify the percentage level of dissolution in the samples.

In recent decades, metasurface have been interested to seek the possibilities of replacing conventional optics such as lens, mirror, and antenna. However, it was quite time-intensive task to design meta-atoms of desired optical properties with traditional design methods, which initialize first and then conducting parametric sweeping for analyzing the structure. Here, we adopted the adaptive moment estimation optimization algorithm to inverse-design the meta-atoms which show similar cross-polarization efficiencies in the broadband visible light region (450nm–650nm). Furthermore, thanks to the metaatoms which utilizes Pancharatnam-Berry phase, we simply obtained the phase-delayed meta-atoms of out-of-phase condition without further calculations. Our future works of integrating every meta-atom into a meta-lens which shows broadband high transmission efficiencies with dispersion-limited behavior.

The high-resolution micro-display is essential component of augment reality and virtual reality devices. The mature fabrication and development of organic light emitting diodes (OLEDs) make the high-resolution micro-OLEDs. Metasurfaces are crucial part to realize the high-resolution micro-OLED. Non-color filter design with constant cavity length of each subpixel have been achieved by meta-mirror which consists of nanoscale silver pillars with distinct diameter and period for each subpixel. In this case, the meta-mirror only served to control the reflection phase, but by adding a dielectric layer to the meta-mirror, it can also function as an absorber. Through this idea, we designed a meta surface to function as a black matrix (BM) by implementing an absorber on the bottom mirror of micro-OLED and verified through simulations that it operates as a BM. From simulations, the designed absorber shows over 90% averaged absorption in whole visible range (400–750 nm) and we demonstrated that the proposed absorber can function as a BM in various designs, including the traditional BM design and the pantile diamond pixel design.

This study focuses on optimizing a Metal-Insulator-Metal (MIM) OLED structure as a plasmonic absorber for advanced micro-display applications. The MIM structure enhances the localized electromagnetic field and improves stability against refractive index variations in the planarization layer during fabrication. The optimization process involved 2D Rigorous Coupled-Wave Analysis (RCWA) simulation to identify resonant modes and parameter dependencies in nanostripe metasurfaces. Additionally, angle-resolved simulations were conducted to observe the spectra response under varying incident angles, demonstrating superior angular sensitivity at zero degrees compared to traditional cavity structures. Results show the MIM structure's superior stability and performance, maintaining consistent resonance conditions despite variations in the planarization layer. This makes the MIM-based approach ideal for high-precision micro-OLED applications.