This PDF file contains the front matter associated with SPIE Proceedings Volume 13187, including the Title Page, Copyright information, Table of Contents, and Conference Committee information.

We study the form and shape of the interferometric patterns obtained in a small angle rotationally shearing interferometer (iRSI) and compare them to those obtained in the traditional Mach-Zehnder interferometer (MZI). We concentrate on low order rotationally asymmetric aberrations, tilt, astigmatism, and coma. We find that the iRSI rotates the interferometric pattern by the angle p/(2l), where l is the second summation index of the wavefront polynomial. Thus, the interferometric patterns for the tilt and coma are rotated by 90 degrees, while those for astigmatism by only 45 degrees, relative to those of the MZI. Additionally, when the experimenter wishes to implement a rotation of the interference pattern in the IRSI, he / she needs to incorporate a relative change of the infinitesimal rotation (dj) from some (δφ)_min to (δφ)_max. However, the true derivative function is accomplished only for an infinitesimal shear angle.

Mechanical stimuli are regulators not only in cells but also in the extracellular matrix activity, with special reference to collagen bundles composition, amount and distribution. Collagen, the major protein in human tissues, contributes to the tissues mechanical properties including ductility under tension and also compressive behavior. However, how mechanical forces in these tissues are translated to mechanotransduction pathways - that ultimately drive the biological response - remains unknown. In this context, 3D imaging methods are necessary to capture the increased complexity that can arise due to high levels of anisotropy and out-of-plane motion, particularly in the disorganized, injured states. An interesting method for 3D imaging and quantitative analysis of collagenous tissues has spread in recent years: it is based on the unique characteristics of synchrotron radiation; it overcome the intrinsic limitations of both histology, achieving only a 2D characterization, and conventional tomographic approaches, poorly resolving the collagenous tissues. In this research, the focus has been placed on our recent researches based on the exploitation of synchrotron-based phase-contrast tomography for the investigation human collagenous tissue physio-pathologies, but also to study the outcome of different tissue-engineering strategies. Encouraging results proved that synchrotron-based imaging is suitable to access and quantify human collagenous tissues. Moreover, with the support of neural networks and deep learning, it is possible to quantify structures in synchrotron phase-contrast images that were not distinguishable before. In particular, collagen bundles can be identified by their orientation and not only by their physical densities, as was made possible using conventional thresholding segmentation techniques. Localised changes in fiber orientation, curvature and strain may involve changes in regional strain transfer and mechanical function, with consequent clinical implications. The comprehension of these kinetics can foster the discovery of therapeutic approaches for the maintaining or re-establishment of correct tissue tensions, as a key to successful and regulated tissues remodeling/repairing and wound healing.

Possibilities of geometric phase using in low-coherence polarization-sensitive tomography tasks for noninvasive diagnostics of surface (subsurface) layers of transparent biological media (samples and tissues) are considered. Determination of the object fields’ geometric phase in the modified Mach-Zehnder interferometer allows one to reproduce the geometric structure (optical axis/collagen orientation) of birefringent biological medium. Polarization-interference noninvasive approach of diagnostics the collagen orientation structure of thin nanosized surface tissue layers is proposed at the first time. It is shown, that taking into account the information about top (surface) layer structure can significantly improve the accuracy of deeper (subsurface) layers parameters estimation. The proposed solution is a unique feature that is not accessible in classical polarization-sensitive techniques of information recovery on tissue structure.

With the aim of applying complex master/slave interferometry (CMSI) to polarizationsensitive optical coherence tomography (PS-OCT) for birefringent tomographic measurements of biological tissue, we present the impact of temperature instability on an all-fiber-based depth-encoded PS-OCT system and the practicality of temperature control for birefringence measurements. In our PS-OCT system, two orthogonally polarized interrogating beams were separated to a depth of approximately 1 mm using a 5-meter long polarization-maintaining fiber (PMF) as a passive delay unit, which is susceptible to temperature instability. The variation in resolution and delay due to temperature change of PMF were investigated. Furthermore, it is shown that tomographic birefringence can be measured under temperature-controlled operation utilizing the advantages of CMSI. We found that changes to the location of generated masks caused by an emerging temperature drift between the channels can be corrected with our presented characterization.

The paper offers a new approach associated with the use of luminescent carbon nanoparticles for the studies of super-smooth surfaces (Rq~4–5 nm). Fluorescent nanoparticles can serve as highly-sensitive probes of the object surface inhomogeneities, realizing a contactless version of the atomic-force profilometry. Using structured light for particles’ fluorescence excitation enables to resolve the fine structural units of the surface relief in the nanometer range. The use of nanoparticles as a probe makes it possible to circumvent the spatial-resolution limitations of optical systems dictated by the classical wave-optics concepts (Rayleigh limit).

Interferometric methods are characterized by high measurement accuracy, and the use of fiber optics allows to be used in hard-to-reach areas. Fiber optic interferometry offers a promising capability to operate in real-time monitoring of metal surface in interacting components. This study uses a fiber optic interferometer as an instrument to estimate the surface conditions and displacement. The proposed solution allows evaluating the distance of the fiber optic end from the material surface to determine the distance and surface condition. Measurements were made in the range of 10-500 μm with a step of 10 μm. Stainless steel samples after sliding friction test were measured. The proposed sensor makes it possible to evaluate the degrees of abrasion of the various surfaces of the interacting components in machines.

Although Titanium and its alloys are generally used for the manufacturing of dental implant abutments, they are typically prone to bacterial infection, due to their implantation in the transgingival region. In close contact with the soft surrounding tissue, the surface may be functionalized in order to improve connective tissue cells adhesion while preventing bacterial penetration at the interface. Ultrafast laser processing of dental implants has demonstrated the potential to obtain unique surface features, down to the nanoscale. With this study, we introduce the possibility to generate laser-induced periodic surface structures (LIPSS) by picosecond laser processing, with periodicity of about 500 nm on large-scale surfaces, in a contamination-free approach. By changing the applied laser dose, different surface coloring of TiAl6V4 samples is obtained due to a gradual surface oxidation, as revealed by depth-profile compositional analyses. In the same time, an increase of the irradiation dose induced the formation of thicker oxide layers, the oxygen content increasing up to ten times. The response of human mesenchymal stem cells (hMSCs) in contact with laser processed surfaces was evaluated to assess samples cytocompatibility. It was demonstrated that large-scale, uniform LIPSS distributed on whole TiAl6V4 surface are beneficial to hMSCs viability and proliferation.

Recently, multi-junction (MJ) solar cells have been researched extensively, due to their potential of achieving improved performance and a higher efficiency as compared to single-junction cells. Various architectures were proposed, and different simulation programs were employed in their analysis. In this paper, we characterized and simulated a high-efficiency GaInP/InGaAs/Ge solar cell, using the software Solcore, a Python-based library. We obtained the I-V characteristics of the cell, at illumination and dark conditions, respectively, and at different temperatures, the carrier density characteristics, and the external quantum efficiency as a function of the wavelength. We estimated the electrical parameters (open-circuit voltage, short-circuit intensity, fill factor and power conversion efficiency) as a function of the temperature (from 0 to 90°C) and of the base layer thickness, comparatively, for several single-junction cells, two alternatives of two-junction cells and the three-junction solar cell. As compared to previous research attempts in the field, we used a different software approach, we evaluated different parameter variations and obtained improved results for the efficiency of the cell. The proposed solar cell can be further improved by the optimization of the junction thickness and modification of doping levels in the layers.

The aim of this paper is to characterize, simulate and optimize the performance characteristics of an organic solar cell. The software resource SCAPS-1D was used to evaluate the characteristics of this organic solar cell, for different values of the most representative device performance parameters (such as the thickness of the organic layer and of the other layers that make up the solar cell, the intensity of light incident on the surface of the device, the electron affinity, etc.) and of the parameters that model the factors that diminish its performance (the density of defects that can appear inside the absorber material, and the effects of increasing the working temperature). The structure of the photovoltaic device was modeled, and characteristics and quantities such as I-V (intensity vs. voltage) characteristic in light and dark conditions, respectively, open-circuit voltage, short-circuit intensity, fill factor, power conversion efficiency and others were simulated and interpreted. By a careful choice of parameters, an improvement of the efficiency of the cell was obtained, from 10.17% to 16.93%. The proposed solar cell can be further optimized by modifying other parameters and properties of the cell layers, while maintaining a good stability performance of the solar cell.

This paper has as a purpose the characterization, simulation (with SCAPS-1D software) and optimization of the performance characteristics of a perovskite solar cell (PSC). The performance of the cell was evaluated by interpreting the results based on the influence of characteristics such as the thickness of the layers, the temperature, the density of defects that may appear inside the absorbing material and at the interfaces, etc. Following the simulations, optimal parameters were determined, which led to a value of 23.49% for the power conversion efficiency (PCE), which is the highest compared to other MAPbI₃-based PSCs simulated with SCAPS-1D that we found in recent literature. The performance of the proposed perovskite solar cell could be further improved by choosing other types of perovskites, and by variations of other characteristics and parameters of the layers.

The authors propose the development of a three-degree-of-freedom hand vibration compensation device, featuring a compliant mechanical structure incorporating three stack-type piezoelectric actuators. Inspired by the Stewart-type mobile platform, the system employs this design to manipulate a laser beam in two directions. Moreover, it facilitates an optimal axial stroke, ensuring precise laser beam focusing. This paper details the comprehensive process, encompassing modeling, simulation, and experimental trials, of a compliant mechanical amplifier designed for powering an innovative laser scalpel prototype. The active tremor damping capability of the proposed system is thoroughly examined, shedding light on its potential applications in medical settings. The authors employed a mechatronic approach, integrating mathematical models, MATLAB simulations and finite element analysis (FEA). Mathematical models were utilized to capture the static deformation of the compliant mechanical structure, providing a theoretical foundation for the subsequent stages of development. MATLAB simulations were then conducted to validate and refine the theoretical models, ensuring their accuracy in representing the system's behavior under various conditions. To further enhance the robustness of the design, finite element analysis (FEA) was employed to validate the structural integrity and performance of the proposed device. This simulation tool allowed for a detailed examination of stress distribution, deformation patterns, and overall mechanical response, guiding refinements to optimize the system's functionality. Expanding upon this, the research underscores the significance of mitigating hand tremors in surgical procedures, emphasizing the practical implications of the developed device.

The article proposes the creation of an image processing application dedicated to laser spot detection, along with an experimental setup designed for the scrutiny of laser spot control. In the conclusive phase of testing the optomechatronic device, a specialized setup was intricately crafted for the precise analysis of the laser spot's position. This experimental arrangement involves the device projecting a laser spot onto graph paper positioned 1.5m away. Horizontally positioned on the shaker, controlled vibrations are imparted to the base of the laser scalpel prototype. A high-resolution video camera captures the laser spot's movement at 2160p and 60 frames per second. Following the tests, MATLAB is employed for video processing, revealing the nuances of the laser spot's motion. The initial test introduces a 10 Hz sinusoidal signal to the shaker, inducing oscillations in the laser spot on the graph paper. A brief video, comprising around 660 frames, is recorded, and subsequently processed to validate the optical processing procedure. This comprehensive methodology establishes a robust foundation for assessing the device's performance, ensuring precise compensation for induced vibrations during laser operation. The experimental findings highlight the efficacy of the proposed mechanism in augmenting the precision and stability of laser-based tools, thereby laying the groundwork for advancements in minimally invasive medical interventions.

The present industry faces numerous challenges in terms of delivering complex products, fast, inexpensive, on time, and with a robust quality level. To achieve these requirements, more and more companies are adopting a strategical orientation toward automation lines. The paper is describing the integration in the traceability systems of flexible systems formed of 3D visions working in synergy with robots to achieve higher levels of autonomy in industrial automation, level 4, High Level Automation, and level 5 Full Automation. This integration is representing a new wave in product inspection and automation level, bringing full transparency under the control of Total Traceability Management (TTM) and assuring new performance levels in terms of quality, flexibility and costs. The increasing complexity of the logistical supply and distribution flow is a consequence of the increased complexity of a vehicle's equipment and components. Increased complexity of the logistics and supply process in values proves that 50 years ago 90% of the vehicle was produced in factories for an OEM (Original Equipment Manufacturer) and today 90% of the vehicle is produced by other suppliers. It is no longer enough to control your own processes and guarantee quality within the OEM factories. The entire logistics chain must deliver a high level of quality, because in the end the materials and assemblies that reach the OEM line must be compliant so that they can be assembled without problems and guarantee the level of quality and safety required for the vehicle. All this must be done under the conditions of flexible production with many customers at the same time, where each vehicle on the OEM assembly lines may differ from the previous or subsequent one in terms of consistent quality and exact delivery times, all in accordance with JIT/JIS principles and in accordance with the specifications in the supply contract with the respective customer.

The paper in question implicitly focusses on validating component eigen frequencies, modal shapes, and damping characteristics within a display base plate component by using experimental modal analysis (EMA) and finite element analysis (FEA). Following this, a 3D component modal simulation results obtained prior physical measurements was performed using Ansys software, extracting eigen frequencies and modal shapes. This fundamental engineering method together with a laser vibrometer monitoring system was used to investigate structures and systems dynamic behavior, understanding vibration phenomena, extracting linear elastic mechanical proprieties through direct measurements, aiding in evaluating base line design structural integrity with the purpose of optimizing the further design. Subsequently, the resonance frequencies obtained from both EMA and FEA were input into Ansys software to perform a comparative study using the Cross Modal Assurance Criterion (CrossMac) method, revealing the level of agreement between them. The comparative analysis revealed a significant correlation between the experimentally eigen frequencies obtained based on laser vibrometer monitoring and obtained by FEA, confirming the precision and utility of the CrossMac method in anticipating the modal characteristics of the tested component. The validation carried out through this method strengthens confidence in the combined approach of EMA with laser vibrometer monitoring and FEA, highlighting the importance of this combination, for a dynamical structural deeper behavior understanding and to strive towards its continual improvement to perfection.

Disruptive technologies have been defined as "new technologies" capable of significant changes in a certain field. Among all, additive manufacturing describes those technologies that build 3D objects by adding layer upon layer of material. Regardless of what a laboratory specializes in, there are chances that 3D printing will improve its processes and performance. 3D printing has also benefited microscopy, enabling the manufacture of microscope parts such as lens inserts, mounts, and objects such as microscopy chambers for storing samples. Generally, such applications allow laboratories to be less dependent on external services and suppliers. This article is presenting a review of the literature in the additive manufacturing field applications, mainly focused on the fine mechanics/optics and opto-mechatronics fields, as well as the authors experience in deriving actual examples of opto-mechanical and opto-mechatronics parts of laboratory instruments (mounts, positioning mechanism including compliant ones, etc.).

Medical images have often unfocused zones that present a challenge for interpretation, as medical diagnosis is given through the optical inspection of the affected region. An algorithm that can adjust the contrast has been developed and presented in this paper. We inspired us from predatory birds, which can focus on the sole region of interest and chose wavelets as a useful mathematical tool. To prevent errors, due to under-exposed real-life images (which can mask medical features) we aimed to develop a reliable algorithm: we tried to improve the optical detection of Computed Tomograph - lung images. We combined a Contrast Limited Adaptive Histogram Equalization with a bihrink filter applied in the wavelet domain. Same as the tactics chosen by predatory birds, wavelets are adjustable devices with can zoom on the region we want to focus, adjusting accordingly the mother wavelet and the iterations level. The results obtained after filtering are accurate, the physiological features are better outlined, and have been graphically displayed for interpretation. As a conclusion, the study focuses on making the optical characteristics of the image better and to limit thus the necessity of contrast substances, which can lead to unnecessary complications (especially in elders and children).

Most animals see little or no color at all. The same fact applies to the Magnetic Resonance technique: the signals are located mostly in shadowy zones interrupted by few light zones. Therefore, the MRAs (Magnetic Resonance Angiograms) are hard to interpret by the physician. MRA offers an image of how the blood spreads through the vessels and organs of the body. Both physician and patient can see where the pathway followed by the blood is blocked. As prevention is better than curing, we focus on finding an algorithm to improve the image contrast and outline the regions of interest. We aim thus to allow an early detection of the illness. For our study, we applied a combined method on biomedical images, to improve their optical contrast: an edge detection algorithm and a strong Matlab contrast-enhancement method named Contrast Limited Adaptive Histogram Equalization. Thus, we should allow the detection of the vascular system or the edges of the organs and improve the chances of an accurate diagnosis. The resulted contrast improvements are visible, unmasking medical features (hidden through the low contrast of the image).

Machine learning algorithms traditionally rely on large datasets for high accuracy. However, advances in the field are now enabling the exploration of solutions in niche engineering areas with smaller datasets. This article reviews the challenges and solutions in working with small datasets, particularly in optoelectronics and biomedical engineering. In optoelectronics, small datasets are key for designing and validating photonic systems, as experiments with living tissues can be costly and complex. The article discusses optimizing photonic response simulations and system calibration using machine learning models that are effective with smaller datasets. In biomedical engineering, the focus is on 3D-printed tissue phantoms, which mimic living tissue properties for non-invasive validation of photonic devices in diagnostics. The study explores how small data techniques like transfer learning, bootstrapping, regularization, and K-fold cross-validation can improve interpretations from small datasets, enhance predictive capabilities, and address data scarcity issues.

Dental whitening is a popular method among patients who want to improve the aesthetics of their smile. It is a relatively inexpensive technique and it has a significant impact on the patient’s confidence. Because of the popularity of this procedure, the scope of modern techniques is to minimize both the duration and the eventual adverse effects, such as postoperative sensitivity. A review was performed in order to compare the effectiveness between in-office conventional bleaching treatment and laser activated bleaching. Another aim of the study was to assess the dental sensitivity following these techniques. Three patients were treated using in-office conventional and diode laser-activated bleaching methods. Even though multiple studies have been concluded that the sensitivity levels are not higher using the conventional method in comparison to modern methods, the postoperative sensibility is related to the concentration and the contact time of the bleaching agent. Therefore, we concluded that laser activated bleaching is not significantly more efficient than the conventional method. However, in comparison to the latter method, the former one minimizes the duration of the procedure and decreases the number of sessions, as well as the dose of bleaching agent. Thus, it causes a lower sensitivity to the patient.

children, especially those with neuro-motor impairments, as they have difficulty in following a form of education. In this paper, i will present the steps taken and the results obtained in the project I coordinated, Micro mobile garden 2.0 - Sensory nature, a project that offers a teaching model based on individual-centered education. This project uses playbased activities and elements of nature (water, earth, herbs) to improve sensory stimulation of children with disabilities. The project involves teachers from different fields, such as: painting/drawing, engineering, plant science and pedagogy. It is focused on the preparation of didactic material for the improvement of cognitive, motor and sensory skills of children with disabilities in a day center in Timișoara. The work makes the transition to the field of medical electronics in order to design the necessary equipment and to set up sensory environment and school designs necessary for the use of people with disabilities.