High-resolution Optical System Research Articles

Layer-level fabrication of continuous functionally graded materials (cFGMs) via Powder Bed Fusion – Laser Beam technology

Multi-material fabrication of metals through Additive Manufacturing (AM) processes is attracting more and more attention in recent years. This work presents a novel methodology that enables the fabrication of continuous functionally graded materials (cFGMs) at the layer level using Powder Bed Fusion – Laser Beam (PBF-LB) technology. This has been achieved by designing and building a customized powder separation system that can be easily installed on a currently operating PBF-LB system with a blade/roller-based powder spreading technique (extremely limited for layer-level multi-material fabrication). This technique overcomes one of the main drawbacks of AM multi-material fabrication by properly joining materials with very different mechanical properties and low compatibility, thus extending the productive capacity of this technology. Two steels, AISI 316 L and 18 Ni Maraging 300, with different physical, chemical and mechanical properties, were used to study the applicability and verify the proposed methodology. A high-resolution optical system was used to monitor, layer by layer, the different laser-matter interactions given by the different materials and thus the presence of a graded transition zone between them. Results in terms of statical mechanical properties, microstructure, chemical analysis and optical monitoring showed that the proposed solution is reliable and cost-effective, paving the way for future applications.

Condensates of magnetoexcitations in quantum Hall dielectrics

The formation and spreading in real space of dense ensembles of photoexcitations in integer and fractional quantum Hall dielectrics with filling factors ν = 2 and ν = 1/3 is visualized using a high-aperture high-resolution optical system. A comparative analysis of the correlation between the transport properties and the spatial coherence of these ensembles is carried out.

Quantitative assessment of chlorine gas inhalation injury based on endoscopic OCT and spectral encoded interferometric microscope imaging with deep learning.

Chlorine exposure can cause severe airway injuries. While the acute effects of chlorine inhalation are well-documented, the structural changes resulting from the post-acute, high-level chlorine exposure remain less understood. Airway sloughing is one of the standards for doctors to evaluate the lung function. Here, we report the application of a high-resolution swept-source optical coherence tomography system to investigate the progression of injury based on airway sloughing evaluation in a chlorine inhalation rabbit model. This system employs a 1.2mm diameter flexible fiberoptic endoscopic probe via an endotracheal tube to capture in vivo large airway anatomical changes before and as early as 30minafter acute chlorine exposure. We conducted an animal study using New Zealand white rabbits exposed to acute chlorine gas (800 ppm, 6min) during ventilation and monitored them using optical coherence tomography (OCT) for 6h. To measure the volume of airway sloughing induced by chlorine gas, we utilized deep learning for the segmentation task on OCT images. The results showed that the volume of chlorine induced epithelial sloughing on rabbit tracheal walls initially increased, peaked around 30min, and then decreased. Furthermore, we utilized a spectral encoded interferometric microscopy system to study ex vivo airway cilia beating dynamics based on Doppler shift, aiding in elucidating how chlorine gas affects cilia beating function. Cilia movability and beating frequency were decreased because of the epithelium damage. This quantitative approach has the potential to enhance the diagnosis and monitoring of injuries from toxic gas inhalation and to evaluate the efficacy of antidote treatments for these injuries.

Design and Evaluation of ScanCap: A Low-Cost, Reusable Tethered Capsule Endoscope with Blue-Green Illumination Imaging for Unsedated Screening and Early Detection of Barrett's Esophagus.

Esophageal carcinoma is the sixth-leading cause of cancer death worldwide. A precursor to esophageal adenocarcinoma (EAC) is Barrett's Esophagus (BE). Early-stage diagnosis and treatment of esophageal neoplasia (Barrett's with high-grade dysplasia/intramucosal cancer) increase the five-year survival rate from 10% to 98%. BE is a global challenge; however, current endoscopes for early BE detection are costly and require extensive infrastructure for patient examination and sedation. We describe the design and evaluation of the first prototype of ScanCap, a high-resolution optical endoscopy system with a reusable, low-cost tethered capsule, designed to provide high-definition, blue-green illumination imaging for the early detection of BE in unsedated patients. The tethered capsule (12.8 mm diameter, 35.5 mm length) contains a color camera and rotating mirror and is designed to be swallowed; images are collected as the capsule is retracted manually via the tether. The tether provides electrical power and illumination at wavelengths of 415 nm and 565 nm and transmits data from the camera to a tablet. The ScanCap prototype capsule was used to image the oral mucosa in normal volunteers and ex vivo esophageal resections; images were compared to those obtained using an Olympus CV-180 endoscope. Images of superficial capillaries in intact oral mucosa were clearly visible in ScanCap images. Diagnostically relevant features of BE, including irregular Z-lines, distorted mucosa, and dilated vasculature, were clearly visible in ScanCap images of ex vivo esophageal specimens.

Optical method to preserve residual hearing in patients receiving a cochlear implant

IntroductionWorldwide, thousands of patients with severe to profound hearing loss restore their hearing with cochlear implant (CI) devices. Newer developments in electrode design and manufacturing and a better understanding of cochlear mechanics allow for conserving critical structures, often translating into serviceable residual hearing and improving device performance. Monitoring insertion speed and intraluminal pressure helps mitigate some of these challenges. However, the information becomes available after irreparable damage has occurred.MethodsWe developed and tested a high-resolution optical system to navigate the intricate anatomy of the cochlea during electrode insertion. The miniaturized optical system was integrated in conventional cochlear implants electrode arrays and custom-made cochlear probes. Electrode insertion were conducted in eight cadaveric human temporal bones and video recordings were acquired. Micro-computed tomography (μCT) scans were performed to evaluate the position of the modified electrode arrays.ResultsFull insertions of the modified CI electrode were successfully conducted and verified by μCT scans. Video recordings of the cochlear structures visible in scala tympani were acquired, and no scala migration was detected.DiscussionSurgeons can now follow the CI electrode's path during its insertion and reduce cochlear damage through early interventions and steering of the CI electrode. Our device will be compatible with robotic platforms that are already available to insert these electrodes.

Low-cost high-resolution distributed optical fiber system for spectrophotometric analysis of liquid samples: Application to detection of azo dyes

A distributed optical fiber system for spectrophotometric analysis of liquid samples based on light diffusing fiber (LDF) is presented. The sensor is based on a high-density white light emitting diode (LED) strip, which is side coupled to a glass based light-diffusing fiber (LDF) that acts as distributed optical receiver. The light emitted from a single LED propagates through the sample medium, is collected by the LDF and is then detected at the end of the fiber by a mini spectrometer. By sequentially turning on one LED at a time, the system permits the spectrophotometric analysis of the sample medium along the entire fiber length. This approach is capable of a continuous monitoring of absorbance spatial profile of liquid sample in the whole visible spectrum with a single low-cost spectrometer. The experimental results confirm the possibility of distributed measurements with a spatial resolution of about 12 mm over 1 m of measurement range. The approach has been successfully employed to the distributed detection and localization of azo dyes in water with a limit of detection lower than 1 ppm.

Condensates of the Magnetoexcitations in Quantum Hall Dielectrics

A high-resolution large-aperture optical system is used to visualize the formation and spreading in real space of dense photoexcitation ensembles in integer and fractional quantum Hall dielectrics at filling factors ν = 2 and ν = 1/3. A comparative analysis is performed of the correlation between the transport properties and spatial coherence of these ensembles.

Design of large field of view and high-resolution compound eye optical system

Design of large field of view and high-resolution compound eye optical system

B-031 Digital Elisatotal 25-Hydroxyvitamin D

Abstract Evaluation of digital ELISA using a high-resolution computational optical system for measurement of total 25-hydroxyvitamin D Background Biomarkers such as vitamin D occur at very low concentrations in blood, and sensitive detection methods are required in order to measure them. It is difficult to accurately measure low-concentration biomarkers using conventional enzyme-linked immunosorbent assays (ELISA) with fluorescence staining. By developing a digital ELISA (DELISA, Small Machines, Seoul, Korea) platform, a low concentration substance was realized by analyzing the digitalized signal through a high-resolution computational optical system in a microfluidic chip. We evaluated DELISA for measurement of total 25-hydroxyvitamin D (25OHD) in a fluidic chip. Methods The sample with monoclonal antibody bead conjugates mixture was incubated for 20 min at 37°C, then 30 uL sample mixture was applied to inlet of the chip. After additional incubation for 2 min at room temperature and 2 min after sample application, 120 uL of washing buffer was applied onto the washing hole and the chip was incubated for 10 min. 25OHD molecules in the sample bond to magnetic beads coupled with anti-25OHD at the end of the membrane. Chips were inserted into DELISA, and 25OHD results were derived by analysis of the computational method of microscopic imaging, proportional to the concentration of 25OHD. Assay performance characteristics of the limit of detection (LoD), precision and analytical measurement interval (AMI) using Vitamin D Depleted, Low and High Serum (Molecular Depot, San Diego, CA) were determined according to the Clinical and Laboratory Standards Institute (CLSI) guidelines. 87 Samples for method comparison studies were obtained from routine clinical samples submitted for 2 OHD determination or from apparently healthy normal volunteers. The study was approved by the Institutional Review Board of Dongguk University Ilsan Hospital (202207024). Results LoD was 10.3 ng/mL and within-laboratory precision was 11, 12, and 10% coefficient of variation at 14.1, 56.6, and 113.2 ng/mL, respectively. The best fit polynomial was a cubic equation from 14.1 to 113.2 ng/mL and the difference between the third-order equation and the first-order equation at Level 3 and 4 concentrations was outside the non-linearity limit. Comparison with chemiluminescent assay (Elecsys Vitamin D total II, Roche Diagnostics, Mannheim, Germany) yielded a 0.904 of correlation coefficient and 0.921 slope in the range from 7.0 to 57.9 ng/mL. Conclusions The DELISA 25OHD assay has a suitable LoD and precision, however, it is necessary to improve the AMI at high concentration values and correlation with the automated analyzer.

An optical-based multipoint 3-axis pressure sensor with a flexible thin-film form.

Multipoint 3-axis tactile pressure sensing by a high-resolution and sensitive optical system provides rich information on surface pressure distribution and plays an important role in a variety of human interaction-related and robotics applications. However, the optical system usually has a bulky profile, which brings difficulties to sensor mounting and system integration. Here, we show a construction of thin-film and flexible multipoint 3-axis pressure sensor by optical methods. The sensor can detect the distribution of 3-axis pressure on an area of 3 centimeter by 4 centimeter, with a high-accuracy normal and tangential pressure sensing up to 360 and 100 kilopascal, respectively. A porous rubber is used as a 3-axis pressure-sensitive optical modulator to omit the thick and rigid focusing system without sacrificing the sensitivity. In addition, by integrating thin and flexible backlight and imager, the sensor has a total thickness of 1.5 milimeter, making it function properly even when bent to a radius of 18 milimeter.

Machine learning assisted cancer cell detection using strip waveguide Bragg gratings

An early cancer diagnosis has become necessary in the medical domain as it can facilitate a timely and appropriate treatment, providing for the clinical management of patients. This work proposes a rapid and inexpensive label-free bio-sensing platform based on Waveguide Bragg Gratings for cancer detection. The refractive index values of cancer cells are different from normal cells, which provide a different reflection spectrum when the sample is placed on the functionalized surface of the waveguide grating structure. We combine simulations from the effective index method, finite element method, and Transfer Matrix method of the Grating structure to optimize the sensing structure and employ a neural network model to predict whether a sample contains cancerous cells. The machine learning model provides excellent accuracy for high-resolution interrogator data, and the accuracy falls below 95% only when the resolution of the interrogator is taken as 0.9 nm, thereby eliminating the need for an expensive high-resolution optical Interrogator system. This, combined with the mass-scale production capability of the waveguide Bragg gratings using standard CMOS technology, paves the way towards combining nano-scale optical biosensing platforms and machine learning-based optimization techniques for early and low-cost label-free cancer detections.

Automatic compact-volume design strategy for unobscured reflective optical systems based on conicoid surfaces

Off-axis reflective optical systems are frequently large in volume to avoid obscuration, and their subsequent optimizations are complex and time-consuming, resulting in volume reduction while sacrificing surface shape complexity. Therefore, this paper proposes an automatic small-volume high-resolution reflective optical system design strategy based on joint aberration model and a global simulated annealing algorithm (SA). The method establishes a comprehensive joint aberration-based imaging quality and volume-constrained evaluation function. Under the premise of ensuring the imaging quality, the volume reduction of two off-axis three-mirror reflective optical systems with large fields of view (FOVs) has been achieved greatly: (1) the volume of the systems with off-axis FOVs was compressed to 22.7% of the conventional method; (2) the volume of the systems with a small F-number, decenter and tilt was compressed to 28.3% of the conventional method, successfully achieving the volume compression of the off-axis reflective optical systems, proving the feasibility and simplicity of this method. This method is more scalable, starting with a conical surface, which can well realize the transition from simple to complex surfaces, providing the choice and comparison of surface types and contributing to the rapid estimation of the system volume.

OPTICAL-ELECTRONIC SYSTEM OF HIGH SPATIAL RESOLUTION WHEN OBSERVING REMOTE OBJECTS

Schematic solutions of an optoelectronic system for obtaining high spatial resolution when observing remote objects are studied, which allow obtaining high resolution of objects in the volume of the observed space, providing high accuracy in determining the coordinates and geometric features of objects in three-dimensional space. A hybrid system is considered for simultaneous registration of the entire set of rays from observed objects in a full solid angle by a high-resolution optical system together with a system for registering sets of different sets of ray directions from objects in the same observed space, which makes it possible to form a set of narrow layers of the observed space in range. To further improve the accuracy of obtaining coordinate and non-coordinate information of the observed objects, the images of narrow layers of space are expanded to the resolution of the first optical registration system by weighted substitution of the detail filters of the discrete wavelet transform. Integration in different digital information ranges is achieved by decomposing the image of the first digital source and each of the set of images of the second digital source into low-frequency and high-frequency components, separate processing of image components based on the principle of weighted summation for each pixel, and the formation of the resulting image. Computational experiments have been carried out showing the effectiveness of the proposed circuit solutions in determining the parameters of objects of interest.

Transport properties of magneto-excitations in integer and fractional quantum Hall insulators

Using a high-resolution optical system, we visualize and compare the real-space transport of the dense ensembles of photoexcitations in integer and fractional quantum Hall insulators at the filling factors ν=2 and ν=1/3. We analyze the correlation between the transport properties and spatial coherence of these ensembles.

A design of supporting structure for realizing large-field-of-view and high-resolution off-axis three-mirror optical system

A design of supporting structure for realizing large-field-of-view and high-resolution off-axis three-mirror optical system

The detection of cervical neoplasia via optical ımaging: a pilot clinical study.

The present study aims to develop a new high-resolution imaging system for the early diagnosis of cervical neoplasia based on increased vessel density of the cervical tissue. An optical device was developed to obtain high contrast and resolution images of vascular structures of the cervix in the present study. The device utilizes a telecentric lens to capture cervix images under light illumination with a wavelength of 550nm emitted from LEDs. Images were obtained using the telecentric lens with or without acetic acid application to the cervix. Image processing algorithms were used to contrast and extract the skeleton of the vascular structures on the cervix. In the evaluation of the vascular density, the cervical images were divided into 12 o'clock positions, and the fractal dimension of the vascularity was calculated for each dial area between the o'clock positions. The region with the largest fractal dimension was accepted as the region with the highest probability of lesion. The range of vessel sizes was split into small classes of "bins" for each dial area with the highest fractal dimension. To validate the system's success in differentiating between normal and HSIL lesions, forty five patients who underwent colposcopy and biopsy were included in a pilot study. The system correctly classified four HSIL cases out of five and failed to detect one HSIL case, achieving an accuracy rate of 97.8% with an 80% sensitivity and 100% specificity. The developed high-resolution optical imaging system may potentially be used in detecting cervical neoplasia just before the biopsy and reduce the number of false-positive cases.

Wide-field-of-view and high-resolution HiLo optical sectioning microscopy system

The predecessor of China Optics was China Optics and Applied Optics Digest, which was founded in 1985. At that time, it was the only retrieval journal in the field of optics in China. At the end of 2008, China Optics and Applied Optics Digest was renamed

Low error-sensitive design of small-sized high-resolution space camera optical system

Low error-sensitive design of small-sized high-resolution space camera optical system

Isolated superfused rats atrial model for the investigation of atrial fibrillation mechanisms and treatment

Abstract Background One of the major barriers to an improved mechanistic understanding of atrial fibrillation (AF), and thus in the pipeline of drug development, has been a lack of appropriate tissue models, especially in small animals. Aim We propose an advanced anatomical ex-vivo model based on rat atria for acute assessment of AF susceptibility. This novel model could yield a better understanding of arrhythmia mechanisms as well as the development of potential therapeutic strategies for the prevention or termination of atrial arrhythmias. Methods Wistar rats atria (N=25) were isolated, flattened and pinned to a custom-made silicon plate. Atria were superfused with an oxygenized Tyrode's solution. Tissues were then loaded with a voltage-sensitive dye and mapped using a high-resolution optical mapping system. AF was induced with 1uM carbamylcholine (N=23) coupled with pacing maneuvers and treated with 30uM Vernakalant (N=10) or 10uM Flecainide (N=10). Finally, the feasibility of a new ablation technique (electroporation) was evaluated. Results Optical mapping results suggested that the superfusion procedure led to a fast atrial recovery. Sinus activity was conserved for all atria for a long period. All the anatomical landmarks were clearly visualized. The acquired optical signals were analyzed during sinus rhythm and pacing, which allowed the creation of detailed activation maps and measurements of action potential duration (APD) and conduction velocity (CV) at different pacing rates. The resulting APD restitution curves revealed electrical excitation at high pacing rates (cycle length between 50ms and 300ms) with a relatively flattened curve. AF was successfully induced and optically mapping confirmed the presence of reentrant activity. AF was successfully treated using Vernacalant and Flecainide. Finally, we demonstrated the feasibility of a new ablation approach (electroporation) for creation of a continuous linear lesion serving as a functional block. Conclusion The isolated superfused atria model, coupled with voltage-sensitive dyes, can be utilized for long-term high-resolution functional imaging of the atria during sinus rhythm, pacing and arrhythmogenic activity. This allows the study of the atrial electrophysiological properties, the mechanisms involved in AF initiation, perpetuation, and termination as well as the study of drug and new ablation modalities. Funding Acknowledgement Type of funding sources: Public grant(s) – EU funding. Main funding source(s): European Research Council (ERC) Spontaneous activation of isolated atria

A stereoscopic optical system for objective quantification of the change in cumulative acne scar depth following various treatment interventions.

Current approaches for assessment of acne scars are subjective, including counting scar subtypes, subjective self-assessment, or scoring global acne scar severity. We aimed to validate accuracy and present initial data of a new, simple, non-contact, high-resolution 3D stereoscopic optical imaging system in the setting of acne scarring. Ten patients treated for acne scars in the dermo-esthetic outpatient clinics in our institution from July to December 2019 were recruited from medical files and completed by telephone interview. Each patient was assessed by the 3D imaging system, the Qualitative Scarring Grading Score (QSGS), and the patient's questionnaire for Self-assessment of Clinical Acne-Related Scars (SCARS) before and 4 weeks after a single intervention. Scar depth measured by the imaging system correlated significantly with the actual depth of printed surface depressions and the 3D optical imaging assessments. The changes in SCARS and 3D optical imaging assessments correlated significantly, but there were no correlations between changes in QSGS and 3D optical assessment measures, or between the QSGS and SCARS results. The new stereoscopic optical system is a reliable and practical objective method for assessing the cumulative depth of atrophic acne scars and monitoring treatment response. It is more sensitive, accurate, and informative than subjective scales.