This PDF file contains the front matter associated with SPIE Proceedings Volume 13487 including the Title Page, Copyright information, Table of Contents, and Conference Committee information.

We obtain an enhanced phase-contrast image of biological samples from the single-shot X-ray phase-contrast imaging technique by using weighted mean filter imaging processing. The center-weighted mean filter is applied to Moiré-less 1stharmonic image restored by Fourier-transform phase-retrieval method. Consequently, the quality of X-ray differential phase-contrast image is drastically improved. The signal-to-noise ratio has been enhanced at least 25.9 % by the enhancement process with the weight value of 1.3. The enhancement of phase information can be explained by the behavior of weight filter in the complex domain.

In this study, we developed a reusable glucose fiber sensor to measure the phase difference produced by the chemical reaction between glucose and glucose oxidase (GOx). The proposed method provides a linear measurement range of glucose concentration from 10 mg/dl to 550 mg/dl, and the best resolution of the proposed method is better than 1 mg/dl. The average relative standard deviation (RSD) is better than 6% which satisfied the criteria of the point-of-care devices.

Experimental measurement of polarization states of the light is crucial in the fundamental and applied optics. However, propagation of coherent light through scattering media generates a random coherent noise known as laser speckle, which obscures the polarization states of the incident light. In this paper, we present a new holography technique to evaluate the Generalized Stokes parameters of the random field, and then use the Generalized Stokes parameters to extract polarization states of the incident beam.

We demonstrate longitudinal drug response imaging of tumor spheroids by integrating a spheroid cultivation chamber and the dynamic optical coherence tomography (DOCT) microscope. The cultivation chamber supports the spheroids with 5% of CO₂ and a temperature of 37°C. In contrast to our previous cross-sectional time-course imaging method, this newly integrated system enables longitudinal time-course imaging of a single sample, and hence enables high-time-resolution imaging of a living sample. It successfully revealed the fine temporal and spatial responses of human breast cancer (MCF-7 cell-line) spheroids to paclitaxel (PTX) and doxorubicin hydrochloride (DOX).

We sought effective height positions at the center part of the nucleus of a living HeLa cell using a bio-Raman microscope, expecting to define the internal state of the living cell. Bio-Raman Non-negative matrix factorization (bio-Raman NMF) was used to provide meaningfully decomposed spectra from complicated Raman spectra of living cells. The heightdependent Raman spectra were successfully and meaningfully factorized into 3 Raman spectral components. All the 3 components seemed effective to define the internal state of a cell.

Nitroxoline is a broad-spectrum drug that effectively treats urinary tract infections (UTIs) without causing a fever. Therefore, estimating the concentrations of nitroxoline spiked in human serum is worth investigating. This study introduces an efficient spectrophotometric method for quantifying nitroxoline in diverse matrices, including bulk samples, Nibiol® tablets, and human serum samples spiked with nitroxoline. This method offers a direct, user-friendly, rapid, and rigorously validated approach for determining nitroxoline content in these various sample types. The investigation was carried out within the framework of a B-R universal buffer system, varying both pH levels and solvent compositions. Optimal outcomes were achieved at a pH of 7, utilizing a 40% (v/v) ethanol solution. The Beer-Lambert law was observed to hold within a concentration range from 5x10^-7 to 1x10^-4 mol L^-1, with a detection limit for nitroxoline in bulk samples established at 1.5x10^-7 mol L^-1. The proposed methodology was effectively applied to quantify nitroxoline in tablet formulations. Comparative analysis between the results obtained through the suggested approach and those derived from standard methodologies demonstrated a favorable concordance. Notably, the excipients present in the tablet formulations did not introduce any interference in the measurements. Furthermore, a limit of detection (LOD) of 1.2x10^-6 mol L^-1 was achieved when analyzing human serum samples spiked with nitroxoline. This approach offers enhanced sensitivity and cost-effectiveness relative to previously described spectrophotometric techniques, rendering it a viable choice for quantifying nitroxoline.

In this study, we trained various pretrained convolutional neural networks to classify Chest X-Ray images. The training dataset consisted of 65 Chest X-Ray images obtained from clinical treatment and classified by expert radiologists. The objective was to differentiate between patients suitable for hyperbaric oxygen therapy and those who are not. The pretrained convolutional neural network architectures we employed included GoogLeNet, ResNet, and VGGNet. Optimal training demonstrated that all pretrained models achieved 100% accuracy on the validation dataset. Results from Grad Class activation mapping indicated that these pretrained models tended to focus on features present in clean lung images. Considering training time, model size, and feature extraction efficiency, GoogLeNet emerged as the most suitable choice for clinical application.

In this study, we employed a dataset of 227 photographs of pressure injuries of various grades to train a range of pretrained convolutional neural network architectures for wound grade classification. These architectures included six types: GoogLeNet, ResNet18, ResNet50, ResNet101, VGG-19, and VGG-16. We fine-tuned parameters such as maximum batch size and maximum epochs to optimize resolution. Concurrently, we utilized the results from Gradient Class Activation Mapping to analyze the reasonableness of each optimized result. Our findings indicate that among the assessed architectures, GoogLeNet is the most suitable for clinical application in a comprehensive evaluation.

Ultrasound is a commonly used tool for diagnosing musculoskeletal disorders. However, interpreting musculoskeletal ultrasound images requires significant expertise due to the complexity of the anatomical structures involved. Developing such skills typically requires extensive training and experience under professional supervision. To streamline this learning process, we have developed an automated annotation system using deep learning neural networks. This system assists in the real-time identification of anatomical structures and has been successfully adapted for clinical use, improving the interpretation of musculoskeletal ultrasound images.

The global performance of RGB OLED displays depends on different factors, such as the emissive properties of the pixels, the illumination conditions, and human perception. In this paper, we present a new automated optical simulation workflow to couple the photonic simulation of the nano- and micro-structure of the pixels with the photometric simulation of the macroscopic display in an illumination scene. We then show a multi-objective optimization for simultaneously achieving high performance across competing metrics at the pixel nanoscale then simulate the display with a Human Vision model to understand the trade-offs at macro scale.

We propose improved ternary-composite-ceramic phosphors for warm-white laser lighting. The ceramic phosphors utilize a red phosphor; (Ba,Sr)₂Si₅N₈:Eu, a yellow phosphor; YAG:Ce, and a thermal conducting matrix. Two types of composite ceramics, Type A is more power-efficient and Type B is effective for more warm light. These composite ceramics have higher saturation input laser power than that of our previous one, in which Sr₂Si₅N₈ is used as for a red phosphor. These improved ceramic phosphors do not show saturation at least 4W pumping laser power, but our previous one does a tendency of saturation at this power. The improved ternary-composite-ceramic phosphors is very useful for warm white laser lighting.

Dirac semimetallic materials have emerged as promising candidates for advancing optoelectronic devices, owing to their distinctive properties in broadband response. Nevertheless, a noteworthy limitation resides in the thickness of these materials, which limits their light absorption capability and device responsivity. In this context, we introduce an experimental method for integrating PtTe₂ and nanostructured silicon. The introduction of pillar-structured silicon enhances the interaction between light and PtTe₂, thereby improving the device's photoresponsivity. Remarkably, under 1550 nm light irradiation, the devices with nanostructured silicon display a consistent and stable photoresponse, demonstrating an approximate 20-fold enhancement in photocurrent compared to the counterparts with planar silicon. This finding provides valuable insights for the development of high-performance optoelectronic devices.

In this paper, we report a novel application of the optical trapping of tracers (e.g., micro- or nanoscale particles) to investigate experimentally a microscale fluid flow induced around a microparticle. In particular, we focus on the thermoosmotic slip flows around a target microparticle fixed on a microchannel. The thermo-osmotic slip flows are creeping fluid flows near a solid surface induced by a temperature gradient of the fluid along the surfaces. By confining optically the tracer motions in a circular path around the circumference of a target microparticle immersed in a fluid with an inhomogeneous temperature field, we successfully visualize the flows induced around the target particle along its surface in a direction from the cold to the hot side. It is found that the magnitude of the observed creeping flow depends on the zeta potential of the target microparticles, i.e., the surface charge.

Orientation control of microparticles of irregular shape is highly needed in various fields such as cell surgery and microassembly. While a lot of techniques have been developed for rotating microparticles with optical tweezers, it is still a difficult task to control orientation (i.e. to stop rotation in a desired posture) of irregular particles with conventional optical tweezers since such particles’ motion with optical tweezers are complex. In this research, to accomplish the task, we propose a concept of adaptive optical tweezers, which realizes 3D orientation control of irregular microparticles by automatically adapting the illumination patterns to the observed shapes of microparticles in real time. In this paper, as a simple realization of adaptive optical tweezers, we report on “contour-shape” optical tweezers, which generate illumination patterns along observed contour shapes of microparticles in real time. Contour-shape optical tweezers are intended to trap irregular microparticles without out-of-plane rotation, which occurs with conventional optical tweezers of one-point illumination. With contour-shape optical tweezers, particles are illuminated only in edge parts, where optical responses can be approximated with those of spheres. Thus, it is expected that the torque applied to a particle is to be cancelled out throughout the particle, so that the particle stops out-of-plane rotation. In the experiment, polystyrene microparticles (~20μm) of irregular shape were trapped with out-of-plane rotation suppressed using contour-shape optical tweezers. This result suggests the feasibility of the concept of adaptive optical tweezers.

We report our evaluation of the spatial resolution of the Stokes camera WPI-200 (Photonic Lattice). We use an interferometer to create polarization fringes, and examine the recorded contrast as a function of spatial frequency. The recorded contrast values were lower than the theoretical value, but no significant dependence on spatial frequency was observed.

In biological membranes, lipids and proteins interact with each other to regulate their functions with complex structure. Manipulation techniques of molecular dynamics are desired to elucidate the regulation mechanism mediated by the interaction of membrane molecules. Optical trapping has been applied to study the biological molecular dynamics since it allows manipulation of biomolecules labeled with single μm-sized particle at the laser focal spot in solution. Due to the complex structure of biological membrane and weak optical trapping forces, it is difficult to investigate the effects of optical trapping on molecules in the biological membrane. In this study, a simple biological membrane model, the substrate-supported lipid bilayer (SLB), was used instead of the complex biological membrane. We investigated the diffusion properties of SLB in an optical trap to clarify the optical trapping dynamics of cell surface molecules. To evaluate the diffusion of lipid molecules, a fluorescent molecule, Texas Red conjugated lipid molecule (TR-PE), was mixed in SLB. The lateral diffusion of TR-PE in an optical trap was estimated by fluorescence correlation spectroscopy (FCS). The diffusion of TR-PE in SLB was slowed down with increasing laser power, suggesting that optical forces act slightly on the molecules in the lipid bilayer. Optical trapping has the potential to assemble molecules in biological membranes due to the difference in diffusion rate of molecules between inside and outside of the focal spot.

Optical vortices possess an orbital angular momentum (OAM). This is characterized by a topological charge (l ) associated with their helical wavefronts. Although difficult to observe directly, the OAM of optical vortices can be clarified by transferring it to materials. The OAM of optical vortices causes a physical "twist" in materials such as metal, silicon, photo-responsive polymer, and even liquid-phase resin. In recent studies, the fabrication of twisted metal nanoneedles melted by nanosecond optical vortex irradiation [1] and the helical polymer fiber formed via photopolymerization reaction by CW optical vortex irradiation [2] have been reported. By using femtosecond laser, photopolymerization occurs only at the focal spot due to two-photon absorption of ultraviolet (UV)-curable resin [3]. Femtosecond optical vortex irradiation resulted in the formation of microstructure that precisely reflect the distribution of electric field intensity [4]. However, the interactions between OAM of optical vortices and materials remain unclear. In this study, we utilize two-photon polymerization reaction of UV-curable resin by femtosecond optical vortex laser irradiation to evaluate the transfer mechanism of the OAM to materials.

Decades of research in the field of tissue engineering have allowed important findings to control cellular behaviors in the lab by designing artificial scaffolds. However, it is still challenging to engineer tissues (i.e. cell collectives with specific functions) that have intrinsic functions equivalent to those in our body. One key element in building such advanced functional tissues is the understanding of structure-cellular function correlations. Specifically, helical structures are seen in many of the tissues in our body, such as the helical structure of skeletal muscle fibers. Yet, no research has investigated the effects of helical structure on cell or tissue level functions due to the lack of technologies to design such helical scaffolds. Herein, we utilized a novel class of helical light field, referred to as an optical vortex, to realize the fabrication of helical scaffolds. By implementing the optical vortex in the photopolymerization of a biocompatible poly(ethylene glycol diacrylate) (PEGDA) scaffold, we expected that the orbital angular momentum of the optical vortex would transfer the helical structure on the fabricated PEGDA gels. Adopting the photo-initiated radical polymerization chemistry, we successfully created PEGDA gels using the optical vortex via single photon and two photon absorption. Although further characterizations are necessary, the helical PEGDA gels fabricated in this study will potentially provide a novel means to investigate how the helical structures affect cellular and tissue-level functions.

In recent years, nanostructures created using optical vortices have attracted much attention. However, the details of the nanostructure formation process have not yet been clarified. In this study, focusing on nanostructures formed by Laguerre-Gaussian beam irradiation, we investigated the assembly dynamics of nanoparticles (NPs) as a model to understand the formation process of chiral nanostructures. Analyzing the fluorescence intensity and areas at the laser focal spot, we evaluated the assembled structure of NPs. Furthermore, particle tracking analysis for NPs attracted to the focal spot from the outside was performed. As a result, NPs assembled in the x-y plane and stacked vertically, where NPs outside the laser focal spot were attracted to the toroidal potential well along the orbit and were eventually trapped.

The standard ISO 25178 includes the latest framework for the calibration, verification and performance specification of areal surface topography measuring instruments. The properties that are subject to a comprehensive calibration and directly contribute to the measurement uncertainty, are referenced as metrological characteristics. ISO 25178-600 describes the basic metrological characteristics that can be applied independently from the measuring principle. To map these characteristics, material measures as defined by ISO 25178-70 are applied. This standard defines 24 different types of material measures that, depending on the individual geometry, have been manufactured using a broad variety of subtractive and additive manufacturing technologies. As areal surface topography measurement is more complex than its profile equivalent, for a comprehensive calibration many metrological characteristics need to be determined. Using multiple case studies, we describe opportunities that the additive manufacturing technology via multi-photon polymerization provides for the implementation of the metrological characteristics framework. These case studies illustrate the versatility that additive manufacturing contributes for the generation of material measures and lead to strategies that allow an efficient implementation of a comprehensive areal calibration.

Water Jet Guided Laser (WJGL) processing uses high-pressure water jet as a waveguide for processing pulse laser. The processing laser is focused and coupled inside the water jet and delivered to the workpiece by total internal reflection (TIR). Therefore, monitoring how the laser propagates inside the water jet is important in maintaining quality processing. In this study, a novel evaluation method for the laser propagation characteristic in the water jet waveguide is suggested utilizing the distribution of Raman scattering which comes out from the water jet in response to the processing laser. In the experiment, the feasibility of this method was demonstrated by comparing it to a conventional evaluation method of water jet breakup and it was applied to the evaluation of laser propagation characteristic during the WJGL drilling process on SiC workpiece. From high-speed imaging of Raman scattering in the water jet, it was found that Raman scattering breaks in the middle of the water jet for most of the pulses once the drilling made certain progress. This breakdown in Raman scattering distribution could suggest that the processing laser did not reach the workpiece for those pulses and therefore that the workpiece was processed only intermittently. The potential for achieving more efficient processing, if such disturbance in the water jet could be controlled, was also suggested.

This study explores the modal sensitivity of a long reflective multimode optical fiber device for angle and temperature detection. Fabricated by splicing approximately 40 cm of multimode optical fiber (50/125), the device generates a random interference reflection spectrum, making wavelength sensitivity analysis impractical for angle detection estimation due to multiple modes. Nevertheless, Fourier phase analysis enables slight angle deflection detection. Three spectral Fourier components were examined, achieving a maximal sensitivity of 1.52 rad/° and a maximum angle variation of 3.4° in the multimode fiber. Thermal analysis indicates minimal temperature impact (0.0065 rad/°C). Strong sensitivity dependence on mode order was demonstrated, making this device appealing for applications requiring precise angle detection given its dimensions and signal analysis capabilities.

It is crucial in a wide range of applications based on optical fiber interference to precisely measure the length difference in optical fiber interferometers. In this article, a method of measuring the absolute length difference between two arms of optical fiber interferometer system based on the phase modulation of light source is proposed. This method enables accurate measurement of length differences and is suitable for both short-distance and long-distance optical fiber interference systems. Only an additional phase modulator needs to be added to realize the measurement, making it easily implementable for compensating and measuring absolute length difference of in-service optical fiber interferometer.

This paper investigates the feasibility of measuring surface form of freeform optics using non-contact multiwavelength interferometry. A bi-conic lens, which is one of the most fundamental freeform optics, was measured on a non-contact multiwavelength interferometer. This lens was characterized by two infinite (flat) radii of curvature along x- and ydirection and two aspheric terms along each direction. Peak-to-valley (PV), root mean square (RMS), and radius of curvature (RoC) parameters were evaluated to characterize the surface form of this lens. To evaluate the measurement repeatability, 5 consecutive measurements were performed on this lens, and it was observed that the standard deviation (3) of PV and RMS was around 29.3 nm and 3.8 nm respectively.

The demonstration of the Spin Hall Effect of Light (SHEL) observation by weak measurement has enabled exploration of the phenomenon in various fields including its application for precision measurement. The sensitivity of SHEL to the optical properties of the medium opens the possibility for precision measurement. Previously, SHEL ellipsometry has shown its potential as surface measurement. In this paper, SHEL ellipsometry is utilized to reconstruct flat optical windows fabricated from different material. Two different models of optical interface are used to solve the SHEL ellipsometry formula, based on air-glass model to retrieve pseudo refractive index value and based on effective medium approximation model to retrieve roughness approximation as effective thickness. This paper further exhibits SHEL potential for surface measurement of smooth surface objects.