Browse Topic: Lasers

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Observers for Laser Safety in the Navigable AirspaceARP5535B (Current)11/26/2025
This document applies to safety observers or spotters involved with the use of outdoor laser systems. It may be used in conjunction with SAE Aerospace Standard (AS4970) “Human Factors Considerations for Outdoor Laser Operations in the Navigable Airspace.” Additional control measures may be applicable and are listed in ANSI Z136.6.
G10T Laser Safety Hazards Committee
Development of Magnesium Laser Powder Bed Fusion to Manufacture Light-weight Components for Vertical Lift ApplicationsF-0077-2021-168145/10/2021
ABSTRACT
Smit, Marc, Hoen-Velterop,  Ludmila, Montero-Sistiaga,  Maria, Paesano, Antonio
Impact of Fog Particles on 1.55 μm Automotive LiDAR Sensor Performance: An Experimental Study in an Enclosed Chamber2021-01-00814/6/2021
To achieve full automation in self-driving vehicles, environmental perception sensing accuracy is critically important. However, ambient particles in adverse weather like foggy, rainy, or snowy conditions can significantly scatter the incident laser beam, and therefore contaminate the intensity and accuracy of light detection and ranging (LiDAR) sensors. Especially compared to the rapidity of technology development in self-driving vehicles, there is a significant lack of documented research on LiDAR systems with wavelength longer than 1 μm for application in Advanced Driver-Assistance Systems. In this work, experimental studies were performed with a state-of-the-art 1.55 μm wavelength automotive-grade LiDAR system in a controlled laboratory fog chamber. The goal of the research is to correlate laser attenuation and the optical properties of fog particles. In this work, a thorough multistep procedure for LiDAR data analysis is presented including spatial averaging of the object measurement and characterizing the temperature effect on a LiDAR intensity parameter. Fog particle density is measured by a commercial visibility sensor instrument. Assuming a constant extinction coefficient and backscatter coefficient, a simple analytical model is derived that correlates LiDAR reflectance and extinction coefficient measured by visibility sensor. Results show that the correlation coefficient between LiDAR and visibility sensor data is 0.98 and the R-squared value of linear fitting is 0.96. By comparing the LiDAR original signal and the model, the Root-Mean-Squared Deviation is 0.007, meaning the model performs very well for predicting LiDAR reflectance in the controlled environment. Furthermore, although the returned signal strength is attenuated, the LiDAR can measure the target with a visibility range lower than six meters.
Zhan, Lu, Northrop, William F.
Research on Automatic Joint Calibration Method of Multi 3D-LIDARs and Inertial Measurement Unit2021-01-00704/6/2021
In the field of automatic driving, the combination of 3D LIDAR and inertial measurement unit (IMU) is a common sensor configuration scheme in laser point-cloud localization, high-precision map making and point-cloud target detection. So it is critical to calibrate LIDAR and IMU accurately. At present, due to the large volume and high cost of 3D LIDAR with high-line-number(Such as 64 lines or 128 lines), the configuration scheme of using multiple low-line-number 3D LIDARs appears in the automatic driving vehicle sensing system. However, the common calibration methods are not suitable for multi 3D LIDARs and IMU parameters calibration on autonomous vehicle, which have the disadvantages of cumbersome implementation and low accuracy. In this paper, a joint calibration test platform composed of dual LIDARs and IMU is assembled, and a method of precise automatic calibration based on GPS/RTK data is proposed. Firstly, the initial parameters of the main 3D LIDAR and IMU are obtained by hand-eye calibration method, and then the motion distortion of the point cloud are removed by using the pose information. After global and local optimization of nearest neighbor error, the conversion parameters from the main LIDAR to IMU are obtained. Then, the remaining LIDARs are calibrated with the main LIDAR by combining coarse registration and fine registration, and finally realize the automatic calibration of external parameters of the entire system. The experimental results show that the proposed method has high calibration accuracy for the system composed of multiple 3D LIDARs and IMU, and the calibration effect is stable.
Zhang, Jinghua, He, Rui, Wu, Jian, Li, Shuai, Chen, Xuesong, Du, Zhiqiang, Chen, Guosheng, Chen, Zhicheng
High-Resolution Circumferential Tire Tread Three-Dimensional Profiling Using Laser Section Technique and Photometric Stereo Technique02-13-01-00013/16/2020
This article presents an approach for circumferential tire tread profiling using Laser Section (LS) technique and Photometric Stereo (PS) technique. The proposed approach uses a digital camera as the only data acquisition device, and one laser line generator and sixteen 5 mm white LEDs to provide different lighting conditions. LS technique uses the illumination of the laser line generator to measure the depth profile of one cross section of the tire surface, while PS technique utilizes the difference of the appearance of the tire surface under different lighting conditions to recover the geometry information of the tire tread with pixel resolution. The fusion of the two techniques results in a high-resolution three-dimensional (3D) profiling of the tire tread. A system to apply the proposed approach was developed, with the necessary calibration steps explained, with a step motor for circumferential measurement. The performance of the proposed approach was validated with a 225/60R16 tire using the system. As shown in the experimental result, the proposed approach has successfully measured the circumferential tire tread profiling with 31 μm spatial resolution.
Song, Mengyu, Furukawa, Tomonari
In-Process Hole and Fastener Inspection Using a High-Accuracy Laser Sensor2020-01-00153/10/2020
Electroimpact has produced a new in-process inspection system for use on drilling and fastening systems. The system uses a high-accuracy, non-contact, laser system to measure the flushness of installed fasteners. The system is also capable of measuring part normality and providing feedback to the machine for correction. One drawback to many automatic inspection systems is measurement error. Many sources of measurement error exist in a production environment, including drilling chips, lubrication, and fastener head markings. Electroimpact’s latest system can create a visualization of the measured fastener for the operator to interpret. This allows the operator to determine the cause of a failed measurement, thus reducing machine downtime due to false negatives.
Luker, Zachary, Stansbury, Erin
Remote, Noninvasive Cardiac Activity Tracer (RENCAT)TBMG-361773/1/2020
NASA Langley Research Center has developed a novel laser vibrometer sensor for monitoring cardiac activities remotely and non-invasively — specifically, heart functions of valve/chamber opening and closing cycles (cardiac cycles). The device provides precise magnitude and timing information, non-invasively and away from the heart region without interference by patient garments.
Researchers Generate Terahertz Laser with Laughing GasTBMG-361473/1/2020
Terahertz waves have frequencies higher than microwaves and lower than infrared and visible light. Where optical light is blocked by most materials, terahertz waves can pass straight through, similar to microwaves. If they were fashioned into lasers, terahertz waves might enable “T-ray vision,” with the ability to see through clothing, book covers, and other thin materials. Such technology could produce crisp, higher-resolution images than microwaves, and be far safer than X-rays.
Researchers Hope to Make Needle Pricks for Diabetics a Thing of the PastTBMG-362403/1/2020
Patients with diabetes have to test their blood sugar levels several times a day to make sure they are not getting too high or too low. Studies have shown that more than half of patients don’t test often enough, in part because of the pain and inconvenience of the needle prick.
Laser Welding ‘Clear-on-Clear’ Plastics for Medical ApplicationsTBMG-362723/1/2020
Through a new process, it is now possible to laser-weld two optically clear plastic parts made of a wide range of polymer materials for medical applications. This innovation combines patented Branson Simultaneous Through-Transmission Infrared® (STTIr®) laser welding technology from Emerson with precision ultrasonic spray deposition technology from Sono-Tek to open up new design possibilities for the makers of medical devices, drug-delivery systems, and in-vitro testing products.
Marubeni Citizen-Cincom Opens New Technical CenterTBMG-362733/1/2020
Marubeni Citizen-Cincom Inc. (MCC) has opened a new technical center in Agawam, MA. The company is holding a ribbon cutting and grand opening celebration March 9. An open house will follow to introduce the company’s new L12 Type X and the new 12 mm laser cutting and welding machine. A variety of Cincom sliding headstock and Miyano fixed headstock lathes will be on display as well. The event will also include technical seminars presented by Sandvik, Esprit, and Gen Swiss.
New Method Detects Defects in 2D MaterialsTBMG-362483/1/2020
Researchers have developed a technique to quickly and sensitively characterize defects in 2D materials used in sensors and electronics. Their solution is to use laser light combined with a phenomenon called second harmonic generation, in which the frequency of the light shone on the material reflects at double the original frequency. Add to this a technique called dark field imaging, in which extraneous light is filtered out so that defects shine through.
Atoms Can Receive Common Communications SignalsTBMG-359862/1/2020
A new type of sensor was developed that uses atoms to receive commonly used communications signals. Cesium atoms were used to receive digital bits (1s and 0s) in the most common communications format used in cellphones, Wi-Fi, and satellite TV. In this format, called phase shifting or phase modulation, radio signals or other electromagnetic waves are shifted relative to one another over time. The information (or data) is encoded in this modulation. The method works across a wide range of frequencies.
SPIE Photonics West 2020 PreviewTBMG-357591/1/2020
The technical conference and exhibition returns to The Moscone Center in San Francisco, February 1 through February 6, offering attendees the opportunity to explore the latest innovations in lasers, photonics, optics, optoelectronics, biophotonics, biomedical optics, 3D printing and more. As in the past, the event will once again kick off with BiOS, the world’s largest biomedical optics conference, before transitioning into the Photonics West conference and exhibition. Last year’s event hosted more than 22,000 attendees and put the products and services of over 1,400 exhibitors on display. More than 5,200 technical papers and 65 course and workshop options will be available to conference participants throughout the week.
Additive Manufacturing of Precision Optics at Micro and NanoscaleTBMG-357631/1/2020
In optical manufacturing, additive manufacturing (AM), as an advanced manufacturing method, has been gaining interest because of its capabilities in the fabrication of extremely complex shapes. Applications of AM in the fabrication of single optical components (e.g. optical crystal) or systems (e.g. the making of an eagle eye) at the microscale or macroscale level have been the focus of recent developments. AM is an especially good fit for products that require a high level of customization.
Laser-Based System Detects Fires Even in Dusty, Harsh EnvironmentsTBMG-357561/1/2020
Researchers have developed a new laser-based system that offers an efficient and low-cost way to detect fires in challenging environments such as industrial facilities or large construction sites. With further development, the system could eventually detect fires that are more than a kilometer away. It could be used in a variety of industries such as waste management facilities, power supply plants, food processing factories, and textile factories.
Microchip Produces High-Contrast OCT ImageryTBMG-357581/1/2020
Scientists at Columbia University, New York, have used a microchip to map the back of the eye for disease diagnosis. The interference technology used in the microchip — like bat sonar but using light instead of sound waves — has been around for a little while. However, this is the first time that technical obstacles have been overcome to fabricate a miniature device able to capture high quality images.
Free-Space Fiber Optic Laser RodTBMG-3570012/1/2019
NASA's Langley Research Center has developed a compact, highly efficient, multi-purpose laser rod. This system employs a modular laser design with highly efficient and compact components. The laser consists of distinct building blocks to achieve wavelengths of 1.0, 1.5, and 2.0 microns. Amplifier modules are based on a novel hybrid fiber rod concept. By confining the otherwise highly divergent pump radiation to a small channel via total internal reflection at a moderately high numerical aperture interface, the low-brightness diodes can pump with high power density over a moderately long absorption path, thereby achieving highly efficient pump absorption.
Photonic Switch Increases Speed and Efficiency of Light Through Optical FibersTBMG-3570612/1/2019
A photonic switch was developed that can control the direction of light passing through optical fibers faster and more efficiently than ever. This optical “traffic cop” could improve how information travels through high-performance supercomputers used for artificial intelligence and other data-intensive applications.
Embedded Fiber Optic Sensors (EFOS)TBMG-3569412/1/2019
Current laser interferometry pressure pulse detection techniques use the shock-induced change in index of refraction to track detonation and/or shock fronts in a single fiber optic by reflecting laser light off the boundary created between the unshocked material and the shocked material. This technique cannot be used in regimes where there isn't a strong enough shock front to reflect the laser light above the noise floor. Other embedded fiber techniques use a chirped fiber Bragg grating to track a shock position versus time by correlating a known spectrum of light to a calibrated position. These two systems use a single fiber and measure only time-of-arrival for a strong shock.
Mathematical Technique Quickly Tunes Next-Generation LensesTBMG-3548011/1/2019
Most of us know optical lenses as curved, transparent pieces of plastic or glass, designed to focus light for microscopes, spectacles, cameras, and more. For the most part, a lens’ curved shape has not changed much since it was invented many centuries ago.
Bringing Precision Anamorphic Micro-Optics to Consumer-Level Laser ApplicationsTBMG-3547511/1/2019
The use of laser light for precise illumination has been limited to high-end applications like optical lithography or small niche markets like measurement technologies. Now that such industries as automotive and consumer electronics are developing and ramping up the production of LIDAR and 3D sensors, laser illumination is scaling in a new direction. For imaging applications, optics made of polymers are already the first choice for such devices as smart cameras. But in order to deliver glass micro-optics with better performance and long-term stability, the cost structure of injection molded polymer optics needed to be addressed.
Researchers Turn off Backscattering, Aim to Improve Optical Data TransmissionTBMG-3547211/1/2019
Engineers at the University of Illinois have found a way to redirect misfit light waves to reduce energy loss during optical data transmission. In a study, researchers exploited an interaction between light and sound waves to suppress the scattering of light from material defects — which could lead to improved fiber optic communication.
Study on Effect of Laser Peening on Inconel 718 Produced by DMLS Technique *CSP Meta Testing 2*2019-28-014610/11/2019
In Additive manufacturing, Direct Metal Laser Sintering (DMLS) is a rapid manufacturing technique used for manufacturing of functional component. Finely powered metal is melted by using high-energy fiber laser, by Island principle strategy that produces mechanically and thermally stable metallic component with reduced stresses, thermal gradients and at high precision. Inconel is an austenitic chromium nickel-based superalloy often used in the applications which require high strength and temperature resistant. It can retain its properties at high temperature. An attempt is made to examine the effect of laser shot peening (LSP) on DMLS Inconel 718 sample. Microstructure shows elliptical shaped structure and formation of new grain boundaries. The surface roughness of the material has been increased due to the effect of laser shock pulse and ablative nature. Macro hardness increased to 13% on the surface. Depth wise microhardness was investigated, found to be 17% increase on the sub-layer of the material due to the effect of a hardened matrix formed by precipitation hardening and grain size refinement attributed by laser shock peening. SEM analysis shows larger grains are being refined into smaller grains. The residual stress analysis result shows compressive residual stress values have increased.
Navin Kumar, Nattudurai, Yadav, Aditya Chandrakant, Raja, Kumar, Prabhakaran, Subramanian, Naiju, Chooriyaparambil Damodaran, Kalainathan, Sivaperuman
Invisible Tags Write, Read, and Erase Using LightTBMG-3526910/1/2019
A method was developed that enables information to be contained in simple plastic foils with a thickness of less than 50 μm, which is thinner than a human hair. Organic luminescent molecules are introduced into the transparent plastic foils. In the beginning, these molecules are in an inactive, dark state; by locally using ultraviolet irradiation, it is possible to turn this dark state into an active, luminescent one.
Dynamic Microstructures Move by Light and TemperatureTBMG-3527010/1/2019
3D printing via direct laser writing involves a computer-controlled focused laser beam that acts as a pen and creates the desired structure in the printer ink — a photoresist. In this way, any three-dimensional form down to the size of a few micrometers can be created.
NIST Research Sparks New Insights on Laser WeldingTBMG-3537310/1/2019
On its surface, the work is deceptively simple: Shoot a high-power laser beam onto a piece of metal for a fraction of a second and see what happens. But researchers say the physics of laser welding is surprisingly complex. A better understanding of the interaction between laser and metal could give industry more control over laser welding, a technology that is becoming increasingly popular in manufacturing.
C919 Trailing Edge Assembly Interchangeable Tooling2019-01-18809/16/2019
Traditional Trailing Edge (TE) assembly that utilise fixtures for accurate positioning of aircraft (a/c) parts do not allow for removal of specific tooling from the fixtures to travel with the TE, post assembly. Instead, the tooling that positions all the primary a/c assembly datums generally utilise precision pins of various sizes that index and clamp the a/c ribs. Often it is difficult to remove the pins post assembly before the spar can be taken out of the fixture. Use of hammers is common place to hit pins out of holes which is less than ideal considering the a/c parts can be fragile and the tooling is precision set. Also, the Main Assembly Fixture (MAJ) that will receive the TE will inevitably need to relocate some if not all the primary a/c ribs and therefore will most likely be subject to some amount of persuasion. Electroimpact have for many years used cup cone locators that allows static tooling to be temporarily ‘loosened’ and therefore made more compliant for pin insertion/removal, this has been successful to reduce the need for hammering, but doesn’t remove the necessity for extensive manual work to reclaim all the datums. The intent of this paper is to highlight how we, on the C919 project, have successfully designed and implemented the use of removable tooling that travels with the TE sub-assemblies into the main TE assembly fixture and similarly the same interchangeable and removable tooling travels with the completed TE and re-engages with identical tooling receivers in the MAJ. Providing a fast, efficient, reduced man-power and accurate means for building a TE and transfer into the MAJ.
Dineley, James
Improving Competitiveness of Additive Manufacturing Aerospace Serial Parts2019-01-19009/16/2019
The Powder Bed Fusion technology is exploding in aerospace industry, with various parts adapted to this process. But one of the main limiting factor to use it in the aircraft industry is quantity of parts that can be manufactured per machine within a year. As a major leader in the aerospace fastener industry, LISI AEROSPACE has a long experience in reducing wasted time. Two activities are developed in this article: Decreasing production time thanks to a support structure reduction and simulation Minimizing unproductive time between two consecutive batches, thanks to manufacturing change improvement (LEAN) We took the example of a serial aircraft part, produced on the CONCEPT LASER M1 machine. With these two activities, we save 253 minutes per production. Originally, we had 4 batches per week; after these activities, we can produce 5 batches per week.
Gas, Maxime, Rene-Corail, Alexis, Eyrignoux, Sebastien, Iker, Guillaume, Sudre, Stephane
3D Meta-Optics for High-Energy LasersTBMG-351189/1/2019
The scope of this research radically changed the way novel components are designed and fabricated for high-energy applications. This 3D Meta-Optics platform was, and is, essentially engineering the electromagnetic fields in 3D dielectric structures. The results have provided a class of transformational optical components that can be integrated at all levels throughout a high-energy laser system.
Simultaneous Imaging and Friction Measurement with an In-Situ TribometerTBMG-351219/1/2019
Different instruments are needed to study the interaction of contact surfaces at different length scales. Tribometers measure the coefficient of friction but they cannot image the microscale or nanoscale contact area. Atomic Force Microscope (AFM) techniques can image surfaces at smaller scales but they do not enable tests to be performed with probe materials (e.g., steel) and properties (e.g., roughness) needed to represent many important, realistic tribological applications. Removing a sample to change instruments can expose the region of interest to environmental contaminants, and can lead to changes in the physical and chemical properties of the sliding zone.
Ultrafast Optics: Vector Cavity Lasers - Physics and Technology19AERP09_109/1/2019
Investigating the operation of fiber lasers where the vector nature of light propagation in the laser cavity is considered. Air Force Research Laboratory, Arlington, Virginia Fiber lasers have found widespread applications in industrial material processing, scientific research and military systems due to their advantages of easy maintenance, excellent stability, compact size and low cost. One characteristic of fiber lasers, compared to other types of lasers, is that strong light is confined to propagating a long distance in a fiber core that has a very small cross-sectional area. This has the consequence that the nonlinear light interaction with the matter has a very long length. This results in the strength of all nonlinear optical processes being strongly amplified. This means that a conventionally weak, nonlinear optical effect can become significant. Therefore, apart from the practical applications, fiber lasers also constitute an ideal platform for the exploration of various complex nonlinear dynamics. Previous studies on the operation of fiber lasers have revealed many interesting nonlinear optical phenomena. Studying these nonlinear optical effects has not only led to a better understanding of the operation of fiber lasers, but also has driven the performance of the fiber lasers to the extreme through exploiting features of the nonlinear optical effects for better laser operation. However, previous studies of fiber lasers have mainly focused on the simple scalar cavity lasers, which ignore the vector nature of light propagation in fibers. For many practical cases, e.g. a fiber laser with a polarization sensitive component in the cavity, this is justified as the existence of the polarization sensitive component fixes the polarization of light in the laser cavity. However, for the comprehensive understanding of the features of fiber lasers, the vector nature of light propagation in the cavity fibers has to be considered. Theoretical studies have shown that the vector light propagation in single mode fibers involves the nonlinear coupling between the two orthogonal polarization components of light, which could introduce a number of new nonlinear dynamics, such as various types of vector soliton formation, polarization domains and domain walls, and black-white vector solitons. The aim of this research project is to investigate the operation of fiber lasers with a quasi-vector cavity both numerically and experimentally. It is expected that through this study, a deep and comprehensive understanding of the operation of fiber lasers could be gained, and fiber lasers with novel features could be further developed.
Ultrafast Optics: Vector Cavity Lasers — Physics and TechnologyTBMG-351059/1/2019
Fiber lasers have found widespread applications in industrial material processing, scientific research and military systems due to their advantages of easy maintenance, excellent stability, compact size and low cost. One characteristic of fiber lasers, compared to other types of lasers, is that strong light is confined to propagating a long distance in a fiber core that has a very small cross-sectional area. This has the consequence that the nonlinear light interaction with the matter has a very long length. This results in the strength of all nonlinear optical processes being strongly amplified. This means that a conventionally weak, nonlinear optical effect can become significant. Therefore, apart from the practical applications, fiber lasers also constitute an ideal platform for the exploration of various complex nonlinear dynamics.
Optical Distance Measurement at Record-High SpeedTBMG-351629/1/2019
Scientists of Karlsruhe Institute of Technology (KIT) and École Poly-technique Fédérale de Lausanne (EPFL) have reported that they achieved the fastest distance measurement attained so far. The researchers demonstrated on-the-fly sampling of a gun bullet profile with micrometer accuracy. The experiment relied on a soliton frequency comb generated in a chip-based optical microresonator made from silicon nitride. Potential applications include real-time 3D cameras based on highly precise and compact LIDAR systems.
Mobile, Dual-Comb Device for Methane Leak DetectionTBMG-351459/1/2019
Accurately detecting, locating, and quantifying leaks of methane — the main component of natural gas and a major fuel source worldwide — is critically important for both environmental and economic reasons. Unfortunately, traditional methods are slow, labor-intensive, limited to small coverage areas, and expensive to operate over time.
Machine Vision Applications in Laser Measurement SystemsTBMG-351679/1/2019
Machine vision is a broad term with many applications and definitions, but at its most basic definition it is using an imager or camera along with software to inspect and analyze a real world object. In addition to the camera and software, machine vision systems usually include lighting, optics, and pass/fail mechanisms.
Laser-Pointing System Transmits Data from Tiny SatellitesTBMG-351549/1/2019
Since 1998, almost 2,000 shoebox-sized satellites known as CubeSats have been launched into space. Due to their small frame and the fact that they can be made from off-the-shelf parts, CubeSats are significantly more affordable to build and launch than traditional satellites that cost hundreds of millions of dollars.
Microrobots Activated by Laser Pulses for Treating TumorsTBMG-351539/1/2019
Microrobots that can deliver drugs to specific spots inside the body while being monitored and controlled from outside the body have been developed that also can treat tumors in the digestive tract.
3D Meta-Optics for High-Energy Lasers19AERP09_099/1/2019
Engineering electromagnetic fields in 3D dielectric structures to change the way components are designed and fabricated for high-energy laser (HEL) applications. Air Force Research Laboratory, Arlington, Virginia The scope of this research radically changed the way novel components are designed and fabricated for high-energy applications. This 3D Meta-Optics platform was, and is, essentially engineering the electromagnetic fields in 3D dielectric structures. The results have provided a class of transformational optical components that can be integrated at all levels throughout a high-energy laser system. A Guided-Mode Resonance Filter (GMRF) is an optically resonant structure consisting of a subwavelength grating (SWG) and a high-index waveguide layer fabricated on a supporting substrate. The devices work based on the electromagnetic coupling of a narrow spectral band from the incident light, due to diffraction by the SWG into leaky waveguide modes, which in turn re-couples to the SWG, and exit the device from the incidence side. This effect results in high reflectance at the desired wavelength band of interest.
Light-Activated Micro-PumpTBMG-349198/1/2019
Even the smallest mechanical pumps have limitations, from the micro-fabrication techniques required to make them to the fact that there are limits on their size. A laser-driven photoacoustic microfluidic pump was developed that is capable of moving fluids in any direction without moving parts or electrical contacts. The pump uses a plasmonic quartz plate implanted with gold atoms to move liquids with a laser that generates an ultrasonic wave.
Virtual Biopsy Device Detects Skin TumorsTBMG-349808/1/2019
Using sound vibrations and pulses of near-infrared light, a new “virtual biopsy” device can quickly determine a skin lesion's depth and potential malignancy without using a scalpel. The first-of-its-kind experimental procedure, called vibrational optical coherence tomography (VOCT), creates a 3D map of the legion's width and depth under the skin with a tiny laser diode. It also uses soundwaves to test the lesion's density and stiffness since cancer cells are stiffer than healthy cells. An inch-long speaker applies audible soundwaves against the skin to measure the skin's vibrations and determine whether the lesion is malignant.
Laser Diode Based on Organic SemiconductorsTBMG-348017/1/2019
Researchers have demonstrated that a long-elusive kind of laser diode based on organic semiconductors is indeed possible, paving the way for the further expansion of lasers in applications such as biosensing, displays, healthcare, and optical communications.
Point Precision Is Critical in Medical Motion ControlTBMG-348157/1/2019
The language used by suppliers of technology solutions aimed at precision engineering applications is vague and, in some instances, confusing. The use of traditional language and words such as precision and resolution without any degree of qualification are just meaningless. This article analyzes the concept of precision. It explores new language for defining submicron- and nanometer-level accuracy for motion control and details why new standards are required to indicate the real levels of precision that different motion control solutions can achieve.
The Influence of SLD Drop Size Distributions on Ice Accretion in the NASA Icing Research Tunnel2019-01-20226/10/2019
An ice shape database has been created to document ice accretions on a 21-inch chord NACA0012 model and a 72-inch chord NACA 23012 airfoil model resulting from an exposure to a Supercooled Large Drop (SLD) icing cloud with a bimodal drop size distribution. The ice shapes created were documented with photographs, laser scanned surface measurements over a section of the model span, and measurement of the ice mass over the same section of each accretion. The icing conditions used in the test matrix were based upon previously used conditions on the same models but with an alternate approach to evaluation of drop distribution effects. Ice shapes resulting from the bimodal distribution as well as from equivalent monomodal drop size distributions were obtained and compared. Results indicate that the ice shapes resulting from the monomodal and bimodal drop size distributions had similar shapes, but the bimodal distributions had greater mass and volume measurements and icing limits that extended further back on the chord of the model.
Potapczuk, Mark G., Tsao, Jen-Ching
Matrix-Free Assisted Laser Desorption Ionization Using Metal-Organic Frameworks19AERP06_106/1/2019
Army Research, Development and Engineering Command, Aberdeen Proving Ground, Maryland Matrix-assisted laser desorption/ionization (MALDI) is a soft ionization technique that is widely applied in the characterization of large biomolecules using various mass spectrometry (MS) analyzers, specifically, time-of-flight (TOF) analyzers. The MALDI process involves the deposition of an analyte solution onto a metal substrate before the addition of a matrix. The matrix/analyte dry spot is exposed to a UV laser, and the laser energy that is absorbed by the matrix/analyte is converted into heat energy that initiates charge transfer, which results in the desorption of the matrix and analyte molecules in ionized form. The positive ions are then accelerated through a vacuum into MS analyses. The MALDI process, however, lacks guiding systematic principles, which has resulted in mostly empirical work. For example, there is no universal matrix that can be used in the MALDI-MS analysis of biomolecules. Hundreds of compounds were assessed with several analytes and were given qualitative ratings. These variables were the products of differences in charge transfer efficiency between the matrix and analytes because of chemical and structural factors.
Matrix-Free Assisted Laser Desorption Ionization Using Metal-Organic FrameworksTBMG-345346/1/2019
Matrix-assisted laser desorption/ionization (MALDI) is a soft ionization technique that is widely applied in the characterization of large biomolecules using various mass spectrometry (MS) analyzers, specifically, time-of-flight (TOF) analyzers. The MALDI process involves the deposition of an analyte solution onto a metal substrate before the addition of a matrix. The matrix/analyte dry spot is exposed to a UV laser, and the laser energy that is absorbed by the matrix/analyte is converted into heat energy that initiates charge transfer, which results in the desorption of the matrix and analyte molecules in ionized form. The positive ions are then accelerated through a vacuum into MS analyses.
Retinas to Roadways: The Evolution of Optical Coherence TechnologyTBMG-346236/1/2019
Insight Photonic Solutions Lafayette, CO
Method Shrinks Objects to the NanoscaleTBMG-344085/1/2019
Existing techniques for creating nano-structures are limited in what they can accomplish. Etching patterns onto a surface with light can produce 2D nano-structures but doesn’t work for 3D structures. It is possible to make 3D nano-structures by gradually adding layers on top of each other, but this process is slow and challenging. And while methods exist that can directly 3D-print nanoscale objects, they are restricted to specialized materials like polymers and plastics that lack the functional properties necessary for many applications. Also, they can only generate self-supporting structures; for example, the technique can yield a solid pyramid, but not a linked chain or a hollow sphere.
Reconstruction of 3D Accident Sites Using USGS LiDAR, Aerial Images, and Photogrammetry2019-01-04234/2/2019
The accident reconstruction community has previously relied upon photographs and site visits to recreate a scene. This method is difficult in instances where the site has changed or is not accessible. In 2017 the United States Geological Survey (USGS) released historical 3D point clouds (LiDAR) allowing for access to digital 3D data without visiting the site. This offers many unique benefits to the reconstruction community including: safety, budget, time, and historical preservation. This paper presents a methodology for collecting this data and using it in conjunction with aerial imagery, and camera matching photogrammetry to create 3D computer models of the scene without a site visit. To determine accuracies achievable using this method, evidence locations solved for using only USGS LiDAR, aerial images and scene photographs (representative of emergency personnel photographs) were compared with known locations documented using total station survey equipment and ground-based 3D laser scanning. The data collected from three different site locations was analyzed, and camera matching photogrammetry was performed independently by 5 different individuals to locate evidence. On average, the resulting evidence for all three test sites was found to be within 3.0 inches (8cm) of known evidence locations with a standard deviation of 1.7 inches (4cm). To further evaluate the quality of the USGS LiDAR, a comparative point cloud analysis of the roadway surfaces was performed. On average, 85% of the USGS LiDAR points were found to be within .5 inches of the ground-based 3D scanning points.
Terpstra, Toby, Dickinson, Jordan, Hashemian, Alireza, Fenton, Stephen
The Teletenna — a Hybrid Telescope Antenna SystemTBMG-341784/1/2019
Innovators at NASA’s Glenn Research Center have developed a hybrid telescope antenna system — Teletenna — to deliver high-data-rate communication over great distances. Teletenna has the potential to benefit deep space missions and communications on Earth. By combining two very different communications systems — optics and radio frequency (RF) — Teletenna capitalizes on the benefits of each system while overcoming conflicting engineering requirements.
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