Laser beam monitoring system

DOEpatents

Weil, B.S.; Wetherington, G.R. Jr.

Laser beam monitoring systems include laser-transparent plates set at an angle to the laser beam passing therethrough and light sensor for detecting light reflected from an object on which the laser beam impinges.

Airborne laser sensors and integrated systems

NASA Astrophysics Data System (ADS)

Sabatini, Roberto; Richardson, Mark A.; Gardi, Alessandro; Ramasamy, Subramanian

2015-11-01

The underlying principles and technologies enabling the design and operation of airborne laser sensors are introduced and a detailed review of state-of-the-art avionic systems for civil and military applications is presented. Airborne lasers including Light Detection and Ranging (LIDAR), Laser Range Finders (LRF), and Laser Weapon Systems (LWS) are extensively used today and new promising technologies are being explored. Most laser systems are active devices that operate in a manner very similar to microwave radars but at much higher frequencies (e.g., LIDAR and LRF). Other devices (e.g., laser target designators and beam-riders) are used to precisely direct Laser Guided Weapons (LGW) against ground targets. The integration of both functions is often encountered in modern military avionics navigation-attack systems. The beneficial effects of airborne lasers including the use of smaller components and remarkable angular resolution have resulted in a host of manned and unmanned aircraft applications. On the other hand, laser sensors performance are much more sensitive to the vagaries of the atmosphere and are thus generally restricted to shorter ranges than microwave systems. Hence it is of paramount importance to analyse the performance of laser sensors and systems in various weather and environmental conditions. Additionally, it is important to define airborne laser safety criteria, since several systems currently in service operate in the near infrared with considerable risk for the naked human eye. Therefore, appropriate methods for predicting and evaluating the performance of infrared laser sensors/systems are presented, taking into account laser safety issues. For aircraft experimental activities with laser systems, it is essential to define test requirements taking into account the specific conditions for operational employment of the systems in the intended scenarios and to verify the performance in realistic environments at the test ranges. To support the development of such requirements, useful guidelines are provided for test and evaluation of airborne laser systems including laboratory, ground and flight test activities.

Laser system using ultra-short laser pulses

DOEpatents

Dantus, Marcos [Okemos, MI; Lozovoy, Vadim V [Okemos, MI; Comstock, Matthew [Milford, MI

2009-10-27

A laser system using ultrashort laser pulses is provided. In another aspect of the present invention, the system includes a laser, pulse shaper and detection device. A further aspect of the present invention employs a femtosecond laser and binary pulse shaping (BPS). Still another aspect of the present invention uses a laser beam pulse, a pulse shaper and a SHG crystal.

Injection locked oscillator system for pulsed metal vapor lasers

DOEpatents

Warner, Bruce E.; Ault, Earl R.

1988-01-01

An injection locked oscillator system for pulsed metal vapor lasers is disclosed. The invention includes the combination of a seeding oscillator with an injection locked oscillator (ILO) for improving the quality, particularly the intensity, of an output laser beam pulse. The present invention includes means for matching the first seeder laser pulses from the seeding oscillator to second laser pulses of a metal vapor laser to improve the quality, and particularly the intensity, of the output laser beam pulse.

Fourier Transform Spectrometer System

NASA Technical Reports Server (NTRS)

Campbell, Joel F. (Inventor)

2014-01-01

A Fourier transform spectrometer (FTS) data acquisition system includes an FTS spectrometer that receives a spectral signal and a laser signal. The system further includes a wideband detector, which is in communication with the FTS spectrometer and receives the spectral signal and laser signal from the FTS spectrometer. The wideband detector produces a composite signal comprising the laser signal and the spectral signal. The system further comprises a converter in communication with the wideband detector to receive and digitize the composite signal. The system further includes a signal processing unit that receives the composite signal from the converter. The signal processing unit further filters the laser signal and the spectral signal from the composite signal and demodulates the laser signal, to produce velocity corrected spectral data.

Attacking the information access problem with expert systems

NASA Technical Reports Server (NTRS)

Ragusa, James M.; Orwig, Gary W.

1991-01-01

The results of applications research directed at finding an improved method of storing and accessing information are presented. Twelve microcomputer-based expert systems shells and five laser-optical formats have been studied, and the general and specific methods of interfacing these technologies are being tested in prototype systems. Shell features and interfacing capabilities are discussed, and results from the study of five laser-optical formats are recounted including the video laser, compact, and WORM disks, and laser cards and film. Interfacing, including laser disk device driver interfacing, is discussed and it is pointed out that in order to control the laser device from within the expert systems application, the expert systems shell must be able to access the device driver software. Potential integrated applications are investigated and an initial list is provided including consumer services, travel, law enforcement, human resources, marketing, and education and training.

Laser device

DOEpatents

Scott, Jill R [Idaho Falls, ID; Tremblay, Paul L [Idaho Falls, ID

2007-07-10

A laser device includes a target position, an optical component separated a distance J from the target position, and a laser energy source separated a distance H from the optical component, distance H being greater than distance J. A laser source manipulation mechanism exhibits a mechanical resolution of positioning the laser source. The mechanical resolution is less than a spatial resolution of laser energy at the target position as directed through the optical component. A vertical and a lateral index that intersect at an origin can be defined for the optical component. The manipulation mechanism can auto align laser aim through the origin during laser source motion. The laser source manipulation mechanism can include a mechanical index. The mechanical index can include a pivot point for laser source lateral motion and a reference point for laser source vertical motion. The target position can be located within an adverse environment including at least one of a high magnetic field, a vacuum system, a high pressure system, and a hazardous zone. The laser source and an electro-mechanical part of the manipulation mechanism can be located outside the adverse environment. The manipulation mechanism can include a Peaucellier linkage.

Laser device

DOEpatents

Scott, Jill R.; Tremblay, Paul L.

2004-11-23

A laser device includes a target position, an optical component separated a distance J from the target position, and a laser energy source separated a distance H from the optical component, distance H being greater than distance J. A laser source manipulation mechanism exhibits a mechanical resolution of positioning the laser source. The mechanical resolution is less than a spatial resolution of laser energy at the target position as directed through the optical component. A vertical and a lateral index that intersect at an origin can be defined for the optical component. The manipulation mechanism can auto align laser aim through the origin during laser source motion. The laser source manipulation mechanism can include a mechanical index. The mechanical index can include a pivot point for laser source lateral motion and a reference point for laser source vertical motion. The target position can be located within an adverse environment including at least one of a high magnetic field, a vacuum system, a high pressure system, and a hazardous zone. The laser source and an electro-mechanical part of the manipulation mechanism can be located outside the adverse environment. The manipulation mechanism can include a Peaucellier linkage.

Laser And Nonlinear Optical Materials For Laser Remote Sensing

NASA Technical Reports Server (NTRS)

Barnes, Norman P.

2005-01-01

NASA remote sensing missions involving laser systems and their economic impact are outlined. Potential remote sensing missions include: green house gasses, tropospheric winds, ozone, water vapor, and ice cap thickness. Systems to perform these measurements use lanthanide series lasers and nonlinear devices including second harmonic generators and parametric oscillators. Demands these missions place on the laser and nonlinear optical materials are discussed from a materials point of view. Methods of designing new laser and nonlinear optical materials to meet these demands are presented.

Dynamically variable spot size laser system

NASA Technical Reports Server (NTRS)

Gradl, Paul R. (Inventor); Hurst, John F. (Inventor); Middleton, James R. (Inventor)

2012-01-01

A Dynamically Variable Spot Size (DVSS) laser system for bonding metal components includes an elongated housing containing a light entry aperture coupled to a laser beam transmission cable and a light exit aperture. A plurality of lenses contained within the housing focus a laser beam from the light entry aperture through the light exit aperture. The lenses may be dynamically adjusted to vary the spot size of the laser. A plurality of interoperable safety devices, including a manually depressible interlock switch, an internal proximity sensor, a remotely operated potentiometer, a remotely activated toggle and a power supply interlock, prevent activation of the laser and DVSS laser system if each safety device does not provide a closed circuit. The remotely operated potentiometer also provides continuous variability in laser energy output.

Fiber Lasers and Amplifiers for Space-based Science and Exploration

NASA Technical Reports Server (NTRS)

Yu, Anthony W.; Krainak, Michael A.; Stephen, Mark A.; Chen, Jeffrey R.; Coyle, Barry; Numata, Kenji; Camp, Jordan; Abshire, James B.; Allan, Graham R.; Li, Steven X.;

Exhaust Plume Measurements of 15-Pound BATES (Ballistic Test and Evaluation System) Motors.

DTIC Science & Technology

1985-06-01

laser transmissometer measurements as a plume... System 7 3 AFRPL Laser Transmission/Scattering Measurement System During Motor Firing 8 4 Laser Scattering Detector Schematic 9 5 Laser Scattering... measurement goals. The instrumentation includes a multi -wavelength, single line-of-sight IR-E/A system , a UV emission spectrometer, an exhaust

Coherent Laser Radar System Theory.

DTIC Science & Technology

1987-11-05

This program is aimed at developing a system theory for the emerging technology of multifunction coherent CO2 laser radars. It builds upon previous...work funded by U.S. Army Research Office contract DAAG29-80-K-0022. Keywords include: Laser radar theory, Radar system theory , and Laser speckle.

Electric motor for laser-mechanical drilling

DOEpatents

Grubb, Daryl L.; Faircloth, Brian O.; Zediker, Mark S.

2015-07-07

A high power laser drilling system utilizing an electric motor laser bottom hole assembly. A high power laser beam travels within the electric motor for advancing a borehole. High power laser drilling system includes a down hole electrical motor having a hollow rotor for conveying a high power laser beam through the electrical motor.

Ultra-fast laser system

DOEpatents

Dantus, Marcos; Lozovoy, Vadim V

2014-01-21

A laser system is provided which selectively excites Raman active vibrations in molecules. In another aspect of the present invention, the system includes a laser, pulse shaper and detection device. A further aspect of the present invention employs a femtosecond laser and binary pulse shaping (BPS). Still another aspect of the present invention uses a laser beam pulse, a pulse shaper and remote sensing.

Laser power conversion system analysis, volume 2

NASA Technical Reports Server (NTRS)

Jones, W. S.; Morgan, L. L.; Forsyth, J. B.; Skratt, J. P.

1979-01-01

The orbit-to-ground laser power conversion system analysis investigated the feasibility and cost effectiveness of converting solar energy into laser energy in space, and transmitting the laser energy to earth for conversion to electrical energy. The analysis included space laser systems with electrical outputs on the ground ranging from 100 to 10,000 MW. The space laser power system was shown to be feasible and a viable alternate to the microwave solar power satellite. The narrow laser beam provides many options and alternatives not attainable with a microwave beam.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Grubb, Daryl L.; Faircloth, Brian O.; Zediker, Mark S.

A high power laser drilling system utilizing an electric motor laser bottom hole assembly. A high power laser beam travels within the electric motor for performing a laser operation. A system includes a down hole electrical motor having a hollow rotor for conveying a high power laser beam having a wavelength less than 1060 nm through the electrical motor.

Radiation beam calorimetric power measurement system

DOEpatents

Baker, John; Collins, Leland F.; Kuklo, Thomas C.; Micali, James V.

1992-01-01

A radiation beam calorimetric power measurement system for measuring the average power of a beam such as a laser beam, including a calorimeter configured to operate over a wide range of coolant flow rates and being cooled by continuously flowing coolant for absorbing light from a laser beam to convert the laser beam energy into heat. The system further includes a flow meter for measuring the coolant flow in the calorimeter and a pair of thermistors for measuring the temperature difference between the coolant inputs and outputs to the calorimeter. The system also includes a microprocessor for processing the measured coolant flow rate and the measured temperature difference to determine the average power of the laser beam.

Target isolation system, high power laser and laser peening method and system using same

DOEpatents

Dane, C. Brent; Hackel, Lloyd A.; Harris, Fritz

2007-11-06

A system for applying a laser beam to work pieces, includes a laser system producing a high power output beam. Target delivery optics are arranged to deliver the output beam to a target work piece. A relay telescope having a telescope focal point is placed in the beam path between the laser system and the target delivery optics. The relay telescope relays an image between an image location near the output of the laser system and an image location near the target delivery optics. A baffle is placed at the telescope focal point between the target delivery optics and the laser system to block reflections from the target in the target delivery optics from returning to the laser system and causing damage.

Tunable solid state lasers for remote sensing; Proceedings of the Conference, Stanford University, CA, October 1-3, 1984

NASA Technical Reports Server (NTRS)

Byer, R. L. (Editor); Trebino, R. (Editor); Gustafson, E. K. (Editor)

1985-01-01

Papers are presented on solid-state lasers for remote sensing, diode-pumped Nd:YAG lasers, and tunable solid-state-laser systems. Topics discussed include titanium-sapphire tunable laser systems, the performance of slab geometry, and the development of slab lasers. Consideration is given to garnet host solid-state lasers, the growth of lasers and nonlinear materials, and nonlinear frequency conversion and tunable sources.

Detection technique of targets for missile defense system

NASA Astrophysics Data System (ADS)

Guo, Hua-ling; Deng, Jia-hao; Cai, Ke-rong

2009-11-01

Ballistic missile defense system (BMDS) is a weapon system for intercepting enemy ballistic missiles. It includes ballistic-missile warning system, target discrimination system, anti-ballistic-missile guidance systems, and command-control communication system. Infrared imaging detection and laser imaging detection are widely used in BMDS for surveillance, target detection, target tracking, and target discrimination. Based on a comprehensive review of the application of target-detection techniques in the missile defense system, including infrared focal plane arrays (IRFPA), ground-based radar detection technology, 3-dimensional imaging laser radar with a photon counting avalanche photodiode (APD) arrays and microchip laser, this paper focuses on the infrared and laser imaging detection techniques in missile defense system, as well as the trends for their future development.

Laser-Induced Damage Threshold and Certification Procedures for Optical Materials

NASA Technical Reports Server (NTRS)

1997-01-01

This document provides instructions for performing laser-induced-damage-threshold tests and pass-fail certification tests on optical materials used in pulsed-laser systems. The optical materials to which these procedures apply include coated and uncoated optical substrates, laser crystals, Q-switches, polarizers, and other optical components employed in pulsed-laser systems.

Computer simulation of a multiple-aperture coherent laser radar

NASA Astrophysics Data System (ADS)

Gamble, Kevin J.; Weeks, Arthur R.

1996-06-01

This paper presents the construction of a 2D multiple aperture coherent laser radar simulation that is capable of including the effects of the time evolution of speckle on the laser radar output. Every portion of a laser radar system is modeled in software, including quarter and half wave plates, beamsplitters (polarizing and non-polarizing), the detector, the laser source, and all necessary lenses. Free space propagation is implemented using the Rayleigh- Sommerfeld integral for both orthogonal polarizations. Atmospheric turbulence is also included in the simulation and is modeled using time correlated Kolmogorov phase screens. The simulation itself can be configured to simulate both monostatic and bistatic systems. The simulation allows the user to specify component level parameters such as extinction ratios for polarizing beam splitters, detector sizes and shapes. orientation of the slow axis for quarter/half wave plates and other components used in the system. This is useful from a standpoint of being a tool in the design of a multiple aperture laser radar system.

Laser ablation system, and method of decontaminating surfaces

DOEpatents

Ferguson, Russell L.; Edelson, Martin C.; Pang, Ho-ming

1998-07-14

A laser ablation system comprising a laser head providing a laser output; a flexible fiber optic cable optically coupled to the laser output and transmitting laser light; an output optics assembly including a nozzle through which laser light passes; an exhaust tube in communication with the nozzle; and a blower generating a vacuum on the exhaust tube. A method of decontaminating a surface comprising the following steps: providing an acousto-optic, Q-switched Nd:YAG laser light ablation system having a fiber optically coupled output optics assembly; and operating the laser light ablation system to produce an irradiance greater than 1.times.10.sup.7 W/cm.sup.2, and a pulse width between 80 and 170 ns.

Apparatus and method to enhance X-ray production in laser produced plasmas

DOEpatents

Augustoni, Arnold L.; Gerardo, James B.; Raymond, Thomas D.

1992-01-01

Method and apparatus for generating x-rays for use in, for instance, x-ray photolithography. The method of generating x-rays includes the steps of providing a target and irradiating the target with a laser system which produces a train of sub-pulses to generate an x-ray producing plasma. The sub-pulses are of both high intensity and short duration. The apparatus for generating x-rays from a plasma includes a vacuum chamber, a target supported within the chamber and a laser system, including a short storage time laser.

Nike Facility Diagnostics and Data Acquisition System

NASA Astrophysics Data System (ADS)

Chan, Yung; Aglitskiy, Yefim; Karasik, Max; Kehne, David; Obenschain, Steve; Oh, Jaechul; Serlin, Victor; Weaver, Jim

2013-10-01

The Nike laser-target facility is a 56-beam krypton fluoride system that can deliver 2 to 3 kJ of laser energy at 248 nm onto targets inside a two meter diameter vacuum chamber. Nike is used to study physics and technology issues related to laser direct-drive ICF fusion, including hydrodynamic and laser-plasma instabilities, material behavior at extreme pressures, and optical and x-ray diagnostics for laser-heated targets. A suite of laser and target diagnostics are fielded on the Nike facility, including high-speed, high-resolution x-ray and visible imaging cameras, spectrometers and photo-detectors. A centrally-controlled, distributed computerized data acquisition system provides robust data management and near real-time analysis feedback capability during target shots. Work supported by DOE/NNSA.

Laser technologies in ophthalmic surgery

NASA Astrophysics Data System (ADS)

Atezhev, V. V.; Barchunov, B. V.; Vartapetov, S. K.; Zav'yalov, A. S.; Lapshin, K. E.; Movshev, V. G.; Shcherbakov, I. A.

2016-08-01

Excimer and femtosecond lasers are widely used in ophthalmology to correct refraction. Laser systems for vision correction are based on versatile technical solutions and include multiple hard- and software components. Laser characteristics, properties of laser beam delivery system, algorithms for cornea treatment, and methods of pre-surgical diagnostics determine the surgical outcome. Here we describe the scientific and technological basis for laser systems for refractive surgery developed at the Physics Instrumentation Center (PIC) at the Prokhorov General Physics Institute (GPI), Russian Academy of Sciences.

Precision laser processing for micro electronics and fiber optic manufacturing

NASA Astrophysics Data System (ADS)

Webb, Andrew; Osborne, Mike; Foster-Turner, Gideon; Dinkel, Duane W.

2008-02-01

The application of laser based materials processing for precision micro scale manufacturing in the electronics and fiber optic industry is becoming increasingly widespread and accepted. This presentation will review latest laser technologies available and discuss the issues to be considered in choosing the most appropriate laser and processing parameters. High repetition rate, short duration pulsed lasers have improved rapidly in recent years in terms of both performance and reliability enabling flexible, cost effective processing of many material types including metal, silicon, plastic, ceramic and glass. Demonstrating the relevance of laser micromachining, application examples where laser processing is in use for production will be presented, including miniaturization of surface mount capacitors by applying a laser technique for demetalization of tracks in the capacitor manufacturing process and high quality laser machining of fiber optics including stripping, cleaving and lensing, resulting in optical quality finishes without the need for traditional polishing. Applications include telecoms, biomedical and sensing. OpTek Systems was formed in 2000 and provide fully integrated systems and sub contract services for laser processes. They are headquartered in the UK and are establishing a presence in North America through a laser processing facility in South Carolina and sales office in the North East.

Femtosecond laser-electron x-ray source

DOEpatents

Hartemann, Frederic V.; Baldis, Hector A.; Barty, Chris P.; Gibson, David J.; Rupp, Bernhard

2004-04-20

A femtosecond laser-electron X-ray source. A high-brightness relativistic electron injector produces an electron beam pulse train. A system accelerates the electron beam pulse train. The femtosecond laser-electron X-ray source includes a high intra-cavity power, mode-locked laser and an x-ray optics system.

Development of a US Gravitational Wave Laser System for LISA

NASA Technical Reports Server (NTRS)

Camp, Jordan B.; Numata, Kenji

2015-01-01

A highly stable and robust laser system is a key component of the space-based LISA mission architecture.In this talk I will describe our plans to demonstrate a TRL 5 LISA laser system at Goddard Space Flight Center by 2016.The laser system includes a low-noise oscillator followed by a power amplifier. The oscillator is a low-mass, compact 10mW External Cavity Laser, consisting of a semiconductor laser coupled to an optical cavity, built by the laser vendorRedfern Integrated Optics. The amplifier is a diode-pumped Yb fiber with 2W output, built at Goddard. I will show noiseand reliability data for the full laser system, and describe our plans to reach TRL 5 by 2016.

Laser Ranging in Solar System: Technology Developments and New Science Measurement Capabilities

NASA Astrophysics Data System (ADS)

Sun, X.; Smith, D. E.; Zuber, M. T.; Mcgarry, J.; Neumann, G. A.; Mazarico, E.

2015-12-01

Laser Ranging has played a major role in geodetic studies of the Earth over the past 40 years. The technique can potentially be used in between planets and spacecrafts within the solar system to advance planetary science. For example, a direct measurement of distances between planets, such as Mars and Venus would make significant improvements in understanding the dynamics of the whole solar system, including the masses of the planets and moons, asteroids and their perturbing interactions, and the gravity field of the Sun. Compared to the conventional radio frequency (RF) tracking systems, laser ranging is potentially more accurate because it is much less sensitive to the transmission media. It is also more efficient because the laser beams are much better focused onto the targets than RF beams. However, existing laser ranging systems are all Earth centric, that is, from ground stations on Earth to orbiting satellites in near Earth orbits or lunar orbit, and to the lunar retro-reflector arrays deployed by the astronauts in the early days of lunar explorations. Several long distance laser ranging experiments have been conducted with the lidar in space, including a two-way laser ranging demonstration between Earth and the Mercury Laser Altimeter (MLA) on the MESSENGER spacecraft over 24 million km, and a one way laser transmission and detection experiment over 80 million km between Earth and the Mars Orbiting Laser Altimeter (MOLA) on the MGS spacecraft in Mars orbit. A one-way laser ranging operation has been carried out continuously from 2009 to 2014 between multiple ground stations to LRO spacecraft in lunar orbit. The Lunar Laser Communication Demonstration (LLCD) on the LADEE mission has demonstrated that a two way laser ranging measurements, including both the Doppler frequency and the phase shift, can be obtained from the subcarrier or the data clocks of a high speed duplex laser communication system. Plans and concepts presently being studied suggest we may be on the cusp of demonstrating interplanetary laser ranging to bring the future of solar system geodesy and geodyamics into reality.

Construction and testing of a Scanning Laser Radar (SLR), phase 2

NASA Technical Reports Server (NTRS)

Flom, T.; Coombes, H. D.

1971-01-01

The scanning laser radar overall system is described. Block diagrams and photographs of the hardware are included with the system description. Detailed descriptions of all the subsystems that make up the scanning laser radar system are included. Block diagrams, photographs, and detailed optical and electronic schematics are used to help describe such subsystem hardware as the laser, beam steerer, receiver optics and detector, control and processing electronics, visual data displays, and the equipment used on the target. Tests were performed on the scanning laser radar to determine its acquisition and tracking performance and to determine its range and angle accuracies while tracking a moving target. The tests and test results are described.

Improved pulse laser ranging algorithm based on high speed sampling

NASA Astrophysics Data System (ADS)

Gao, Xuan-yi; Qian, Rui-hai; Zhang, Yan-mei; Li, Huan; Guo, Hai-chao; He, Shi-jie; Guo, Xiao-kang

2016-10-01

Narrow pulse laser ranging achieves long-range target detection using laser pulse with low divergent beams. Pulse laser ranging is widely used in military, industrial, civil, engineering and transportation field. In this paper, an improved narrow pulse laser ranging algorithm is studied based on the high speed sampling. Firstly, theoretical simulation models have been built and analyzed including the laser emission and pulse laser ranging algorithm. An improved pulse ranging algorithm is developed. This new algorithm combines the matched filter algorithm and the constant fraction discrimination (CFD) algorithm. After the algorithm simulation, a laser ranging hardware system is set up to implement the improved algorithm. The laser ranging hardware system includes a laser diode, a laser detector and a high sample rate data logging circuit. Subsequently, using Verilog HDL language, the improved algorithm is implemented in the FPGA chip based on fusion of the matched filter algorithm and the CFD algorithm. Finally, the laser ranging experiment is carried out to test the improved algorithm ranging performance comparing to the matched filter algorithm and the CFD algorithm using the laser ranging hardware system. The test analysis result demonstrates that the laser ranging hardware system realized the high speed processing and high speed sampling data transmission. The algorithm analysis result presents that the improved algorithm achieves 0.3m distance ranging precision. The improved algorithm analysis result meets the expected effect, which is consistent with the theoretical simulation.

Closed cycle electric discharge laser design investigation

NASA Technical Reports Server (NTRS)

Baily, P. K.; Smith, R. C.

1978-01-01

Closed cycle CO2 and CO electric discharge lasers were studied. An analytical investigation assessed scale-up parameters and design features for CO2, closed cycle, continuous wave, unstable resonator, electric discharge lasing systems operating in space and airborne environments. A space based CO system was also examined. The program objectives were the conceptual designs of six CO2 systems and one CO system. Three airborne CO2 designs, with one, five, and ten megawatt outputs, were produced. These designs were based upon five minute run times. Three space based CO2 designs, with the same output levels, were also produced, but based upon one year run times. In addition, a conceptual design for a one megawatt space based CO laser system was also produced. These designs include the flow loop, compressor, and heat exchanger, as well as the laser cavity itself. The designs resulted in a laser loop weight for the space based five megawatt system that is within the space shuttle capacity. For the one megawatt systems, the estimated weight of the entire system including laser loop, solar power generator, and heat radiator is less than the shuttle capacity.

Apparatus and method to enhance X-ray production in laser produced plasmas

DOEpatents

Augustoni, A.L.; Gerardo, J.B.; Raymond, T.D.

1992-12-29

Method and apparatus for generating x-rays for use in, for instance, x-ray photolithography is disclosed. The method of generating x-rays includes the steps of providing a target and irradiating the target with a laser system which produces a train of sub-pulses to generate an x-ray producing plasma. The sub-pulses are of both high intensity and short duration. The apparatus for generating x-rays from a plasma includes a vacuum chamber, a target supported within the chamber and a laser system, including a short storage time laser. 8 figs.

Systems and assemblies for transferring high power laser energy through a rotating junction

DOEpatents

Norton, Ryan J.; McKay, Ryan P.; Fraze, Jason D.; Rinzler, Charles C.; Grubb, Daryl L.; Faircloth, Brian O.; Zediker, Mark S.

2016-01-26

There are provided high power laser devices and systems for transmitting a high power laser beam across a rotating assembly, including optical slip rings and optical rotational coupling assemblies. These devices can transmit the laser beam through the rotation zone in free space or within a fiber.

Flight demonstration of laser diode initiated ordnance

NASA Technical Reports Server (NTRS)

Boucher, Craig J.; Schulze, Norman R.

1995-01-01

A program has been initiated by NASA Headquarters to validate laser initiated ordnance in flight applications. The primary program goal is to bring together a team of government and industry members to develop a laser initiated ordnance system having the test and analysis pedigree to be flown on launch vehicles. The culmination of this effort was a flight of the Pegasus launch vehicle which had two fin rockets initiated by this laser system. In addition, a laser initiated ordnance squib was fired into a pressure bomb during thrusting flight. The complete ordnance system comprising a laser diode firing unit, fiber optic cable assembly, laser initiated detonator, and laser initiated squib was designed and built by The Ensign Bickford Company. The hardware was tested to the requirements of the Pegasus launch vehicle and integrated into the vehicle by The Ensign Bickford Company and the Orbital Sciences Corporation. Discussions include initial program concept, contract implementation, team member responsibilities, analysis results, vehicle integration, safing architecture, ordnance interfaces, mission timeline and telemetry data. A complete system description, summary of the analyses, the qualification test results, and the results of flight are included.

Performance calculation and simulation system of high energy laser weapon

NASA Astrophysics Data System (ADS)

Wang, Pei; Liu, Min; Su, Yu; Zhang, Ke

2014-12-01

High energy laser weapons are ready for some of today's most challenging military applications. Based on the analysis of the main tactical/technical index and combating process of high energy laser weapon, a performance calculation and simulation system of high energy laser weapon was established. Firstly, the index decomposition and workflow of high energy laser weapon was proposed. The entire system was composed of six parts, including classical target, platform of laser weapon, detect sensor, tracking and pointing control, laser atmosphere propagation and damage assessment module. Then, the index calculation modules were designed. Finally, anti-missile interception simulation was performed. The system can provide reference and basis for the analysis and evaluation of high energy laser weapon efficiency.

Performance of the upgraded Orroral laser ranging system

NASA Technical Reports Server (NTRS)

Luck, John M.

1993-01-01

The topics discussed include the following: upgrade arrangements, system prior to 1991, elements of the upgrade, laser performance, timing system performance, pass productivity, system precision, system accuracy, telescope pointing and future upgrades and extensions.

Programmable phase plate for tool modification in laser machining applications

DOEpatents

Thompson Jr., Charles A.; Kartz, Michael W.; Brase, James M.; Pennington, Deanna; Perry, Michael D.

2004-04-06

A system for laser machining includes a laser source for propagating a laser beam toward a target location, and a spatial light modulator having individual controllable elements capable of modifying a phase profile of the laser beam to produce a corresponding irradiance pattern on the target location. The system also includes a controller operably connected to the spatial light modulator for controlling the individual controllable elements. By controlling the individual controllable elements, the phase profile of the laser beam may be modified into a desired phase profile so as to produce a corresponding desired irradiance pattern on the target location capable of performing a machining operation on the target location.

Method and system for homogenizing diode laser pump arrays

DOEpatents

Bayramian, Andrew James

2016-05-03

An optical amplifier system includes a diode pump array including a plurality of semiconductor diode laser bars disposed in an array configuration and characterized by a periodic distance between adjacent semiconductor diode laser bars. The periodic distance is measured in a first direction perpendicular to each of the plurality of semiconductor diode laser bars. The diode pump array provides a pump output propagating along an optical path and characterized by a first intensity profile measured as a function of the first direction and having a variation greater than 10%. The optical amplifier system also includes a diffractive optic disposed along the optical path. The diffractive optic includes a photo-thermo-refractive glass member. The optical amplifier system further includes an amplifier slab having an input face and position along the optical path and separated from the diffractive optic by a predetermined distance. A second intensity profile measured at the input face of the amplifier slab as a function of the first direction has a variation less than 10%.

Method and system for homogenizing diode laser pump arrays

DOEpatents

Bayramian, Andy J

2013-10-01

An optical amplifier system includes a diode pump array including a plurality of semiconductor diode laser bars disposed in an array configuration and characterized by a periodic distance between adjacent semiconductor diode laser bars. The periodic distance is measured in a first direction perpendicular to each of the plurality of semiconductor diode laser bars. The diode pump array provides a pump output propagating along an optical path and characterized by a first intensity profile measured as a function of the first direction and having a variation greater than 10%. The optical amplifier system also includes a diffractive optic disposed along the optical path. The diffractive optic includes a photo-thermo-refractive glass member. The optical amplifier system further includes an amplifier slab having an input face and position along the optical path and separated from the diffractive optic by a predetermined distance. A second intensity profile measured at the input face of the amplifier slab as a function of the first direction has a variation less than 10%.

Portable remote laser sensor for methane leak detection

NASA Technical Reports Server (NTRS)

Grant, W. B.; Hinkley, E. D., Jr. (Inventor)

1984-01-01

A portable laser system for remote detection of methane gas leaks and concentrations is disclosed. The system transmitter includes first and second lasers, tuned respectively to a wavelength coincident with a strong absorption line of methane and a reference wavelength which is weakly absorbed by methane gas. The system receiver includes a spherical mirror for collecting the reflected laser radiation and focusing the collected radiation through a narrowband optical filter onto an optial detector. The filter is tuned to the wavelength of the two lasers, and rejects background noise. The output of the optical detector is processed by a lock-in detector synchronized to the chopper, and which measures the difference between the first wavelength signal and the reference wavelength signal.

Laser spark distribution and ignition system

DOEpatents

Woodruff, Steven [Morgantown, WV; McIntyre, Dustin L [Morgantown, WV

2008-09-02

A laser spark distribution and ignition system that reduces the high power optical requirements for use in a laser ignition and distribution system allowing for the use of optical fibers for delivering the low peak energy pumping pulses to a laser amplifier or laser oscillator. An optical distributor distributes and delivers optical pumping energy from an optical pumping source to multiple combustion chambers incorporating laser oscillators or laser amplifiers for inducing a laser spark within a combustion chamber. The optical distributor preferably includes a single rotating mirror or lens which deflects the optical pumping energy from the axis of rotation and into a plurality of distinct optical fibers each connected to a respective laser media or amplifier coupled to an associated combustion chamber. The laser spark generators preferably produce a high peak power laser spark, from a single low power pulse. The laser spark distribution and ignition system has application in natural gas fueled reciprocating engines, turbine combustors, explosives and laser induced breakdown spectroscopy diagnostic sensors.

Formation of propagation invariant laser beams with anamorphic optical systems

NASA Astrophysics Data System (ADS)

Soskind, Y. G.

2015-03-01

Propagation invariant structured laser beams play an important role in several photonics applications. A majority of propagation invariant beams are usually produced in the form of laser modes emanating from stable laser cavities. This work shows that anamorphic optical systems can be effectively employed to transform input propagation invariant laser beams and produce a variety of alternative propagation invariant structured laser beam distributions with different shapes and phase structures. This work also presents several types of anamorphic lens systems suitable for transforming the input laser modes into a variety of structured propagation invariant beams. The transformations are applied to different laser mode types, including Hermite-Gaussian, Laguerre-Gaussian, and Ince-Gaussian field distributions. The influence of the relative azimuthal orientation between the input laser modes and the anamorphic optical systems on the resulting transformed propagation invariant beams is presented as well.

Design and Development of a Package for a Diluted Waveguide Electro-Absorption Modulator

DTIC Science & Technology

2008-11-01

the coupling efficiency. A design including mechanical, optical and RF elements was developed. A Newport Laser Welding system was utilized for...results, a design including mechanical, optical and RF elements was developed. A Newport Laser Welding system was utilized for fiber placement and...fixation. The laser welding techniques were customized in order to meet the needs of the EAM package design. Keywords: Electroabsorption

VSF Measurements and Inversion for RaDyO

DTIC Science & Technology

2012-09-30

near-surface waters, including the surf zone. APPROACH MASCOT (Multi-Angle SCattering Optical Tool) has a 30 mW 658 nm laser diode source...in Santa Barbara Channel are provided in Fig. 1. Despite the widespread use of polarized laser sources across a diversity of Navy applications, this...operations that rely on divers, cameras, laser imaging systems, and active and passive remote sensing systems. These include mine countermeasures, harbor

Control, Filtering and Prediction for Phased Arrays in Directed Energy Systems

DTIC Science & Technology

2016-04-30

adaptive optics. 15. SUBJECT TERMS control, filtering, prediction, system identification, adaptive optics, laser beam pointing, target tracking, phase... laser beam control; furthermore, wavefront sensors are plagued by the difficulty of maintaining the required alignment and focusing in dynamic mission...developed new methods for filtering, prediction and system identification in adaptive optics for high energy laser systems including phased arrays. The

Optical air data systems and methods

NASA Technical Reports Server (NTRS)

Spaeth, Lisa G. (Inventor); O'Brien, Martin (Inventor); Tang, Shoou-yu (Inventor); Acott, Phillip E. (Inventor); Caldwell, Loren M. (Inventor)

2011-01-01

Systems and methods for sensing air includes at least one, and in some embodiments three, transceivers for projecting the laser energy as laser radiation to the air. The transceivers are scanned or aligned along several different axes. Each transceiver receives laser energy as it is backscattered from the air. A computer processes signals from the transceivers to distinguish molecular scattered laser radiation from aerosol scattered laser radiation and determines air temperatures, wind speeds, and wind directions based on the scattered laser radiation. Applications of the system to wind power site evaluation, wind turbine control, traffic safety, general meteorological monitoring and airport safety are presented.

Laser systems configured to output a spectrally-consolidated laser beam and related methods

DOEpatents

Koplow, Jeffrey P [San Ramon, CA

2012-01-10

A laser apparatus includes a plurality of pumps each of which is configured to emit a corresponding pump laser beam having a unique peak wavelength. The laser apparatus includes a spectral beam combiner configured to combine the corresponding pump laser beams into a substantially spatially-coherent pump laser beam having a pump spectrum that includes the unique peak wavelengths, and first and second selectively reflective elements spaced from each other to define a lasing cavity including a lasing medium therein. The lasing medium generates a plurality of gain spectra responsive to absorbing the pump laser beam. Each gain spectrum corresponds to a respective one of the unique peak wavelengths of the substantially spatially-coherent pump laser beam and partially overlaps with all other ones of the gain spectra. The reflective elements are configured to promote emission of a laser beam from the lasing medium with a peak wavelength common to each gain spectrum.

Laser beam delivery at ELI-NP

DOE PAGES

Ursescu, Daniel; Cheriaux, G.; Audebert, P.; ...

2017-01-01

The Laser Beam Delivery (LBD) system technical design report covers the interface between the High Power Laser System (HPLS) and the experiments, together with the pulse quality management. Here, the laser transport part of the LBD has a number of subsystems as follows: the beam transport lines for the six main outputs of HPLS, the additional short and long pulses and the synchronization system including the timing of the laser pulses with the Gamma Beam System (GBS) and the experiments on femtosecond timescale. Pulse quality management, discussed further here, consist in the generation and delivery of multiple HPLS pulses, coherentmore » combining of the HPLS arms, laser pulse diagnostics on target, laser beam dumps, shutters and output energy adaption.« less

Design of a solar-pumped frequency-doubled 532 nm Nd:YVO4 laser

NASA Astrophysics Data System (ADS)

Kittiboonanan, P.; Putchana, W.; Deeudomand, M.; Ratanavis, A.

2017-09-01

During the last year we have made progresson a development of a frequency-doubled 532 nm Nd:YVO4 laser pumped by solar light. The research aimed to demonstrate solar pumped lasers consisting of the optically contracted Nd:YVO4 crystal and KTP crystal with a system of laser mirrors deposited onto crystal sides. The Cassegrain reflector is used as the configuration. This solar pumped laser system is appealing for a variety applications including laser communication, imaging and defense applications.

Fiber lasers and amplifiers for science and exploration at NASA Goddard Space Flight Center

NASA Technical Reports Server (NTRS)

Krainak, Michael A.; Abshire, James; Allan, Graham R.; Stephen Mark

2005-01-01

We discuss present and near-term uses for high-power fiber lasers and amplifiers for NASA- specific applications including planetary topography and atmospheric spectroscopy. Fiber lasers and amplifiers offer numerous advantages for both near-term and future deployment of instruments on exploration and science remote sensing orbiting satellites. Ground-based and airborne systems provide an evolutionary path to space and a means for calibration and verification of space-borne systems. We present experimental progress on both the fiber transmitters and instrument prototypes for ongoing development efforts. These near-infrared instruments are laser sounders and lidars for measuring atmospheric carbon dioxide, oxygen, water vapor and methane and a pseudo-noise (PN) code laser ranging system. The associated fiber transmitters include high-power erbium, ytterbium, neodymium and Raman fiber amplifiers. In addition, we will discuss near-term fiber laser and amplifier requirements and programs for NASA free space optical communications, planetary topography and atmospheric spectroscopy.

Tunable solid-state laser technology for applications to scientific and technological experiments from space

NASA Technical Reports Server (NTRS)

Allario, F.; Taylor, L. V.

1986-01-01

Current plans for the Earth Observing System (EOS) include development of a lidar facility to conduct scientific experiments from a polar orbiting platforms. A recommended set of experiments were scoped, which includes techniques of atmospheric backscatter (Lidar), Differential Absorption Lidar (DIAL), altimetry, and retroranging. Preliminary assessments of the resources (power, weight, volume) required by the Eos Lidar Facility were conducted. A research program in tunable solid state laser technology was developed, which includes laser materials development, modeling and experiments on the physics of solid state laser materials, and development of solid state laser transmitters with a strong focus on Eos scientific investigations. Some of the system studies that were conducted which highlight the payoff of solid state laser technology for the Eos scientific investigations will be discussed. Additionally, a summary of some promising research results which have recently emerged from the research program will be presented.

Laser-Ultrasonic Testing and its Applications to Nuclear Reactor Internals

NASA Astrophysics Data System (ADS)

Ochiai, M.; Miura, T.; Yamamoto, S.

2008-02-01

A new nondestructive testing technique for surface-breaking microcracks in nuclear reactor components based on laser-ultrasonics is developed. Surface acoustic wave generated by Q-switched Nd:YAG laser and detected by frequency-stabilized long pulse laser coupled with confocal Fabry-Perot interferometer is used to detect and size the cracks. A frequency-domain signal processing is developed to realize accurate sizing capability. The laser-ultrasonic testing allows the detection of surface-breaking microcrack having a depth of less than 0.1 mm, and the measurement of their depth with an accuracy of 0.2 mm when the depth exceeds 0.5 mm including stress corrosion cracking. The laser-ultrasonic testing system combined with laser peening system, which is another laser-based maintenance technology to improve surface stress, for inner surface of small diameter tube is developed. The generation laser in the laser-ultrasonic testing system can be identical to the laser source of the laser peening. As an example operation of the system, the system firstly works as the laser-ultrasonic testing mode and tests the inner surface of the tube. If no cracks are detected, the system then changes its work mode to the laser peening and improves surface stress to prevent crack initiation. The first nuclear industrial application of the laser-ultrasonic testing system combined with the laser peening was completed in Japanese nuclear power plant in December 2004.

Advances in laser technology and fibre-optic delivery systems in lithotripsy.

PubMed

Fried, Nathaniel M; Irby, Pierce B

2018-06-08

The flashlamp-pumped, solid-state holmium:yttrium-aluminium-garnet (YAG) laser has been the laser of choice for use in ureteroscopic lithotripsy for the past 20 years. However, although the holmium laser works well on all stone compositions and is cost-effective, this technology still has several fundamental limitations. Newer laser technologies, including the frequency-doubled, double-pulse YAG (FREDDY), erbium:YAG, femtosecond, and thulium fibre lasers, have all been explored as potential alternatives to the holmium:YAG laser for lithotripsy. Each of these laser technologies is associated with technical advantages and disadvantages, and the search continues for the next generation of laser lithotripsy systems that can provide rapid, safe, and efficient stone ablation. New fibre-optic approaches for safer and more efficient delivery of the laser energy inside the urinary tract include the use of smaller-core fibres and fibres that are tapered, spherical, detachable or hollow steel, or have muzzle brake distal fibre-optic tips. These specialty fibres might provide advantages, including improved flexibility for maximal ureteroscope deflection, reduced cross section for increased saline irrigation rates through the working channel of the ureteroscope, reduced stone retropulsion for improved stone ablation efficiency, and reduced fibre degradation and burnback for longer fibre life.

Photoluminescence-based quality control for thin film absorber layers of photovoltaic devices

DOEpatents

Repins, Ingrid L.; Kuciauskas, Darius

2015-07-07

A time-resolved photoluminescence-based system providing quality control during manufacture of thin film absorber layers for photovoltaic devices. The system includes a laser generating excitation beams and an optical fiber with an end used both for directing each excitation beam onto a thin film absorber layer and for collecting photoluminescence from the absorber layer. The system includes a processor determining a quality control parameter such as minority carrier lifetime of the thin film absorber layer based on the collected photoluminescence. In some implementations, the laser is a low power, pulsed diode laser having photon energy at least great enough to excite electron hole pairs in the thin film absorber layer. The scattered light may be filterable from the collected photoluminescence, and the system may include a dichroic beam splitter and a filter that transmit the photoluminescence and remove scattered laser light prior to delivery to a photodetector and a digital oscilloscope.

Mitigating intrinsic defects and laser damage using pulsetrain-burst (>100 MHz) ultrafast laser processing

NASA Astrophysics Data System (ADS)

McKinney, Luke; Frank, Felix; Graper, David; Dean, Jesse; Forrester, Paul; Rioblanc, Maxence; Nantel, Marc; Marjoribanks, Robin

2005-09-01

Ultrafast-laser micromachining has promise as an approach to trimming and 'healing' small laser-produced damage sites in laser-system optics--a common experience in state-of-the-art high-power laser systems. More-conventional approaches currently include mechanical micromachining, chemical modification, and treatment using cw and long-pulse lasers. Laser-optics materials of interest include fused silica, multilayer dielectric stacks for anti-reflection coatings or high-reflectivity mirrors, and inorganic crystals such as KD*P, used for Pockels cells and frequency-doubling. We report on novel efforts using ultrafast-laser pulsetrain-burst processing (microsecond bursts at 133 MHz) to mitigate damage in fused silica, dielectric coatings, and KD*P crystals. We have established the characteristics of pulsetrain-burst micromachining in fused silica, multilayer mirrors, and KD*P, and determined the etch rates and morphology under different conditions of fluence-delivery. From all of these, we have begun to identify new means to optimize the laser-repair of optics defects and damage.

Suppression of Laser Shot Noise Using Laser-Cooled OptoMechanical Systems

DTIC Science & Technology

2010-04-22

that this device will be able to demonstrate squeezing in a fairly short time . Background: The goal of this effort was to create laser light with...The public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing...REPORT Final report on Seedling project: "Suppression of Laser Shot Noise Using Laser -Cooled Opto-Mechanical Systems" 14. ABSTRACT 16. SECURITY

Active imaging system with Faraday filter

DOEpatents

Snyder, James J.

1993-01-01

An active imaging system has a low to medium powered laser transmitter and receiver wherein the receiver includes a Faraday filter with an ultranarrow optical bandpass and a bare (nonintensified) CCD camera. The laser is locked in the vicinity of the passband of the Faraday filter. The system has high sensitivity to the laser illumination while eliminating solar background.

Active imaging system with Faraday filter

DOEpatents

Snyder, J.J.

1993-04-13

An active imaging system has a low to medium powered laser transmitter and receiver wherein the receiver includes a Faraday filter with an ultranarrow optical bandpass and a bare (nonintensified) CCD camera. The laser is locked in the vicinity of the passband of the Faraday filter. The system has high sensitivity to the laser illumination while eliminating solar background.

Applications of lasers and electro-optics

NASA Astrophysics Data System (ADS)

Tan, B. C.; Low, K. S.; Chen, Y. H.; Ahmad, Harith; Tou, T. Y.

Supported by the IRPA Programme on Laser Technology and Applications, many types of lasers have been designed, constructed and applied in various areas of science, medicine and industries. Amongst these lasers constructed were high power carbon dioxide lasers, rare gas halide excimer lasers, solid state Neodymium-YAG lasers, nitrogen lasers, flashlamp pumped dye lasers and nitrogen and excimer laser pumped dye lasers. These lasers and the associated electro-optics system, some with computer controlled, are designed and developed for the following areas of applications: (1) industrial applications of high power carbon dioxide lasers for making of i.c. components and other materials processing purposes -- prototype operational systems have been developed; (2) Medical applications of lasers for cancer treatment using the technique of photodynamic therapy -- a new and more effective treatment protocol has been proposed; (3) agricultural applications of lasers in palm oil and palm fruit-fluorescence diagnostic studies -- fruit ripeness signature has been developed and palm oil oxidation level were investigated; (4) development of atmospheric pollution monitoring systems using laser lidar techniques -- laboratory scale systems were developed; and (5) other applications of lasers including laser holographic and interferometric methods for the non destructive testing of materials.

Computer laser system for prevention and treatment of dental diseases: new methods and results

NASA Astrophysics Data System (ADS)

Fedyai, S. G.; Prochonchukov, Alexander A.; Zhizhina, Nina A.; Metelnikov, Michael A.

1995-05-01

We report results of clinical application of the new computer-laser system. The system includes hardware and software means, which are applied for new efficient methods of prevention and treatment of main dental diseases. The hardware includes a laser physiotherapeutic device (LPD) `Optodan' and a fiberoptic laser delivery system with special endodontic rigging. The semiconductor AG-AL-AG laser diode with wavelengths in the spectral range of 850 - 950 nm (produced by Scientific-Industrial Concern `Reflector') is used as a basic unit. The LPD `Optodan' and methods of treatment are covered by Russian patent No 2014107 and certified by the Russian Ministry of Health. The automated computer system allows us to examine patients quickly and to input differential diagnosis, to determine indications (and contraindications), parameters and regimen of laser therapy, to control treatment efficacy (for carious -- through clinical indexes of enamel solubles, velocity of demineralization and other tests; for periodontal diseases trough complex of the periodontal indexes with automated registry and calculation). We present last results of application of the new technique and methods in treatment of dental diseases in Russian clinics.

Method for generating a plasma wave to accelerate electrons

DOEpatents

Umstadter, D.; Esarey, E.; Kim, J.K.

1997-06-10

The invention provides a method and apparatus for generating large amplitude nonlinear plasma waves, driven by an optimized train of independently adjustable, intense laser pulses. In the method, optimal pulse widths, interpulse spacing, and intensity profiles of each pulse are determined for each pulse in a series of pulses. A resonant region of the plasma wave phase space is found where the plasma wave is driven most efficiently by the laser pulses. The accelerator system of the invention comprises several parts: the laser system, with its pulse-shaping subsystem; the electron gun system, also called beam source, which preferably comprises photo cathode electron source and RF-LINAC accelerator; electron photo-cathode triggering system; the electron diagnostics; and the feedback system between the electron diagnostics and the laser system. The system also includes plasma source including vacuum chamber, magnetic lens, and magnetic field means. The laser system produces a train of pulses that has been optimized to maximize the axial electric field amplitude of the plasma wave, and thus the electron acceleration, using the method of the invention. 21 figs.

Method for generating a plasma wave to accelerate electrons

DOEpatents

Umstadter, Donald; Esarey, Eric; Kim, Joon K.

1997-01-01

The invention provides a method and apparatus for generating large amplitude nonlinear plasma waves, driven by an optimized train of independently adjustable, intense laser pulses. In the method, optimal pulse widths, interpulse spacing, and intensity profiles of each pulse are determined for each pulse in a series of pulses. A resonant region of the plasma wave phase space is found where the plasma wave is driven most efficiently by the laser pulses. The accelerator system of the invention comprises several parts: the laser system, with its pulse-shaping subsystem; the electron gun system, also called beam source, which preferably comprises photo cathode electron source and RF-LINAC accelerator; electron photo-cathode triggering system; the electron diagnostics; and the feedback system between the electron diagnostics and the laser system. The system also includes plasma source including vacuum chamber, magnetic lens, and magnetic field means. The laser system produces a train of pulses that has been optimized to maximize the axial electric field amplitude of the plasma wave, and thus the electron acceleration, using the method of the invention.

Mobile terawatt laser propagation facility (Conference Presentation)

NASA Astrophysics Data System (ADS)

Shah, Lawrence; Roumayah, Patrick; Bodnar, Nathan; Bradford, Joshua D.; Maukonen, Douglas; Richardson, Martin C.

2017-03-01

This presentation will describe the design and construction status of a new mobile high-energy femtosecond laser systems producing 500 mJ, 100 fs pulses at 10 Hz. This facility is built into a shipping container and includes a cleanroom housing the laser system, a separate section for the beam director optics with a retractable roof, and the environmental control equipment necessary to maintain stable operation. The laser system includes several innovations to improve the utility of the system for "in field" experiments. For example, this system utilizes a fiber laser oscillator and a monolithic chirped Bragg grating stretcher to improve system robustness/size and employs software to enable remote monitoring and system control. Uniquely, this facility incorporates a precision motion-controlled gimbal altitude-azimuth mount with a coudé path to enable aiming of the beam over a wide field of view. In addition to providing the ability to precisely aim at multiple targets, it is also possible to coordinate the beam with separate tracking/diagnostic sensing equipment as well as other laser systems. This mobile platform will be deployed at the Townes Institute Science and Technology Experimental Facility (TISTEF) located at the Kennedy Space Center in Florida, to utilize the 1-km secured laser propagation range and the wide array of meteorological instrumentation for atmospheric and turbulence characterization. This will provide significant new data on the propagation of high peak power ultrashort laser pulses and detailed information on the atmospheric conditions in a coastal semi-tropical environment.

An All-Solid-State High Repetiton Rate Titanium:Sapphire Laser System For Resonance Ionization Laser Ion Sources

NASA Astrophysics Data System (ADS)

Mattolat, C.; Rothe, S.; Schwellnus, F.; Gottwald, T.; Raeder, S.; Wendt, K.

2009-03-01

On-line production facilities for radioactive isotopes nowadays heavily rely on resonance ionization laser ion sources due to their demonstrated unsurpassed efficiency and elemental selectivity. Powerful high repetition rate tunable pulsed dye or Ti:sapphire lasers can be used for this purpose. To counteract limitations of short pulse pump lasers, as needed for dye laser pumping, i.e. copper vapor lasers, which include high maintenance and nevertheless often only imperfect reliability, an all-solid-state Nd:YAG pumped Ti:sapphire laser system has been constructed. This could complement or even replace dye laser systems, eliminating their disadvantages but on the other hand introduce shortcomings on the side of the available wavelength range. Pros and cons of these developments will be discussed.

Injection locking of a high power ultraviolet laser diode for laser cooling of ytterbium atoms

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hosoya, Toshiyuki; Miranda, Martin; Inoue, Ryotaro

2015-07-15

We developed a high-power laser system at a wavelength of 399 nm for laser cooling of ytterbium atoms with ultraviolet laser diodes. The system is composed of an external cavity laser diode providing frequency stabilized output at a power of 40 mW and another laser diode for amplifying the laser power up to 220 mW by injection locking. The systematic method for optimization of our injection locking can also be applied to high power light sources at any other wavelengths. Our system does not depend on complex nonlinear frequency-doubling and can be made compact, which will be useful for providing light sources formore » laser cooling experiments including transportable optical lattice clocks.« less

Development of laser transmission system

NASA Astrophysics Data System (ADS)

Song, Jiawu; Zhang, Yulan; Yang, Jiandong; Zhang, Xinming

1998-08-01

This paper discusses a light transfer system of therapeutic machine using carbon-dioxide laser. This system is based on imitating human being arm motion principle, consists of optical cardans mainly and can move in three-D space freely. Through it carbon-dioxide laser (which wavelength is 10.6 micrometer) is reflected, focused or diverged and transferred to the different therapeutic part of body to realize the purpose of cutting operation, gasification, cauterization and irradiation. This system includes an indicating system using He-Ne laser, by which carbon-dioxide laser can arrive therapeutic part accurately. This system possesses some advantages e.g. an accurate transfer, large moving range, small power consumption, high power density and easy operation. At present the occupancy in home market of this kind laser transfer system products is over 95%. Some products have been exported to other countries.

Method and system for compact, multi-pass pulsed laser amplifier

DOEpatents

Erlandson, Alvin Charles

2014-11-25

A laser amplifier includes an input aperture operable to receive laser radiation having a first polarization, an output aperture coupled to the input aperture by an optical path, and a polarizer disposed along an optical path. A transmission axis of the polarizer is aligned with the first polarization. The laser amplifier also includes n optical switch disposed along the optical path. The optical switch is operable to pass the laser radiation when operated in a first state and to reflect the laser radiation when operated in a second state. The laser amplifier further includes an optical gain element disposed along the optical path and a polarization rotation device disposed along the optical path.

NASA three-laser airborne differential absorption lidar system electronics

NASA Technical Reports Server (NTRS)

Allen, R. J.; Copeland, G. D.

1984-01-01

The system control and signal conditioning electronics of the NASA three laser airborne differential absorption lidar (DIAL) system are described. The multipurpose DIAL system was developed for the remote measurement of gas and aerosol profiles in the troposphere and lower stratosphere. A brief description and photographs of the majority of electronics units developed under this contract are presented. The precision control system; which includes a master control unit, three combined NASA laser control interface/quantel control units, and three noise pulse discriminator/pockels cell pulser units; is described in detail. The need and design considerations for precision timing and control are discussed. Calibration procedures are included.

Design and characterization of a novel power over fiber system integrating a high power diode laser

NASA Astrophysics Data System (ADS)

Perales, Mico; Yang, Mei-huan; Wu, Cheng-liang; Hsu, Chin-wei; Chao, Wei-sheng; Chen, Kun-hsein; Zahuranec, Terry

2017-02-01

High power 9xx nm diode lasers along with MH GoPower's (MHGP's) flexible line of Photovoltaic Power Converters (PPCs) are spurring high power applications for power over fiber (PoF), including applications for powering remote sensors and sensors monitoring high voltage equipment, powering high voltage IGBT gate drivers, converters used in RF over Fiber (RFoF) systems, and system power applications, including powering UAVs. In PoF, laser power is transmitted over fiber, and is converted to electricity by photovoltaic cells (packaged into Photovoltaic Power Converters, or PPCs) which efficiently convert the laser light. In this research, we design a high power multi-channel PoF system, incorporating a high power 976 nm diode laser, a cabling system with fiber break detection, and a multichannel PPC-module. We then characterizes system features such as its response time to system commands, the PPC module's electrical output stability, the PPC-module's thermal response, the fiber break detection system response, and the diode laser optical output stability. The high power PoF system and this research will serve as a scalable model for those interested in researching, developing, or deploying a high power, voltage isolated, and optically driven power source for high reliability utility, communications, defense, and scientific applications.

Recycling of laser and plasma radiation energy for enhancement of extreme ultraviolet sources for nanolithography

NASA Astrophysics Data System (ADS)

Sizyuk, V.; Sizyuk, T.; Hassanein, A.; Johnson, K.

2018-01-01

We have developed comprehensive integrated models for detailed simulation of laser-produced plasma (LPP) and laser/target interaction, with potential recycling of the escaping laser and out-of-band plasma radiation. Recycling, i.e., returning the escaping laser and plasma radiation to the extreme ultraviolet (EUV) generation region using retroreflective mirrors, has the potential of increasing the EUV conversion efficiency (CE) by up to 60% according to our simulations. This would result in significantly reduced power consumption and/or increased EUV output. Based on our recently developed models, our High Energy Interaction with General Heterogeneous Target Systems (HEIGHTS) computer simulation package was upgraded for LPP devices to include various radiation recycling regimes and to estimate the potential CE enhancement. The upgraded HEIGHTS was used to study recycling of both laser and plasma-generated radiation and to predict possible gains in conversion efficiency compared to no-recycling LPP devices when using droplets of tin target. We considered three versions of the LPP system including a single CO2 laser, a single Nd:YAG laser, and a dual-pulse device combining both laser systems. The gains in generating EUV energy were predicted and compared for these systems. Overall, laser and radiation energy recycling showed the potential for significant enhancement in source efficiency of up to 60% for the dual-pulse system. Significantly higher CE gains might be possible with optimization of the pre-pulse and main pulse parameters and source size.

Research and Development of Laser Diode Based Instruments for Applications in Space

NASA Technical Reports Server (NTRS)

Krainak, Michael; Abshire, James; Cornwell, Donald; Dragic, Peter; Duerksen, Gary; Switzer, Gregg

1999-01-01

Laser diode technology continues to advance at a very rapid rate due to commercial applications such as telecommunications and data storage. The advantages of laser diodes include, wide diversity of wavelengths, high efficiency, small size and weight and high reliability. Semiconductor and fiber optical-amplifiers permit efficient, high power master oscillator power amplifier (MOPA) transmitter systems. Laser diode systems which incorporate monolithic or discrete (fiber optic) gratings permit single frequency operation. We describe experimental and theoretical results of laser diode based instruments currently under development at NASA Goddard Space Flight Center including miniature lidars for measuring clouds and aerosols, water vapor and wind for Earth and planetary (Mars Lander) use.

Precision and resolution in laser direct microstructuring with bursts of picosecond pulses

NASA Astrophysics Data System (ADS)

Mur, Jaka; Petkovšek, Rok

2018-01-01

Pulsed laser sources facilitate various applications, including efficient material removal in different scientific and industrial applications. Commercially available laser systems in the field typically use a focused laser beam of 10-20 μm in diameter. In line with the ongoing trends of miniaturization, we have developed a picosecond fiber laser-based system combining fast beam deflection and tight focusing for material processing and optical applications. We have predicted and verified the system's precision, resolution, and minimum achievable feature size for material processing applications. The analysis of the laser's performance requirements for the specific applications of high-precision laser processing is an important aspect for further development of the technique. We have predicted and experimentally verified that maximal edge roughness of single-micrometer-sized features was below 200 nm, including the laser's energy and positioning stability, beam deflection, the effect of spot spacing, and efficient isolation of mechanical vibrations. We have demonstrated that a novel fiber laser operating regime in bursts of pulses increases the laser energy stability. The results of our research improve the potential of fiber laser sources for material processing applications and facilitate their use through enabling the operation at lower pulse energies in bursts as opposed to single pulse regimes.

Laser diode initiated detonators for space applications

NASA Technical Reports Server (NTRS)

Ewick, David W.; Graham, J. A.; Hawley, J. D.

1993-01-01

Ensign Bickford Aerospace Company (EBAC) has over ten years of experience in the design and development of laser ordnance systems. Recent efforts have focused on the development of laser diode ordnance systems for space applications. Because the laser initiated detonators contain only insensitive secondary explosives, a high degree of system safety is achieved. Typical performance characteristics of a laser diode initiated detonator are described in this paper, including all-fire level, function time, and output. A finite difference model used at EBAC to predict detonator performance, is described and calculated results are compared to experimental data. Finally, the use of statistically designed experiments to evaluate performance of laser initiated detonators is discussed.

Yb:FAP and related materials, laser gain medium comprising same, and laser systems using same

DOE Office of Scientific and Technical Information (OSTI.GOV)

Krupke, William F.; Payne, Stephen A.; Chase, Lloyd L.

An ytterbium doped laser material remarkably superior to all others, including Yb:YAG, comprises Ytterbium doped apatite (Yb:Ca.sub.5 (PO.sub.4).sub.3 F) or Yb:FAP, or ytterbium doped crystals that are structurally related to FAP. The new laser material is used in laser systems pumped by diode pump sources having an output near 0.905 microns or 0.98 microns, such as InGaAs and AlInGaAs, or other narrowband pump sources near 0.905 microns or 0.98 microns. The laser systems are operated in either the conventional or ground state depletion mode.

Yb:FAP and related materials, laser gain medium comprising same, and laser systems using same

DOE Office of Scientific and Technical Information (OSTI.GOV)

Krupke, W.F.; Payne, S.A.; Chase, L.L.

An ytterbium doped laser material remarkably superior to all others, including Yb:YAG, comprises ytterbium doped apatite (Yb:Ca[sub 5](PO[sub 4])[sub 3]F) or Yb:FAP, or ytterbium doped crystals that are structurally related to FAP. The new laser material is used in laser systems pumped by diode pump sources having an output near 0.905 microns or 0.98 microns, such as InGaAs and AlInGaAs, or other narrowband pump sources near 0.905 microns or 0.98 microns. The laser systems are operated in either the conventional or ground state depletion mode. 9 figures.

Yb:FAP and related materials, laser gain medium comprising same, and laser systems using same

DOEpatents

Krupke, W.F.; Payne, S.A.; Chase, L.L.; Smith, L.K.

1994-01-18

An ytterbium doped laser material remarkably superior to all others, including Yb:YAG, comprises ytterbium doped apatite (Yb:Ca[sub 5](PO[sub 4])[sub 3]F) or Yb:FAP, or ytterbium doped crystals that are structurally related to FAP. The new laser material is used in laser systems pumped by diode pump sources having an output near 0.905 microns or 0.98 microns, such as InGaAs and AlInGaAs, or other narrowband pump sources near 0.905 microns or 0.98 microns. The laser systems are operated in either the conventional or ground state depletion mode. 9 figures.

Yb:FAP and related materials, laser gain medium comprising same, and laser systems using same

DOE Office of Scientific and Technical Information (OSTI.GOV)

Krupke, W.F.; Payne, S.A.; Chase, L.L.

An ytterbium doped laser material remarkably superior to all others, including Yb:YAG, comprises ytterbium doped apatite (Yb:Ca{sub 5}(PO{sub 4}){sub 3}F) or Yb:FAP, or ytterbium doped crystals structurally related to FAP. The new laser material is used in laser systems pumped by diode pump sources having an output near 0.905 microns or 0.98 microns, such as InGaAs and AlInGaAs, or other narrowband pump sources near 0.905 microns or 0.98 microns. The laser systems are operated in either the conventional or ground state depletion mode.

The fast and accurate 3D-face scanning technology based on laser triangle sensors

NASA Astrophysics Data System (ADS)

Wang, Jinjiang; Chang, Tianyu; Ge, Baozhen; Tian, Qingguo; Chen, Yang; Kong, Bin

2013-08-01

A laser triangle scanning method and the structure of 3D-face measurement system were introduced. In presented system, a liner laser source was selected as an optical indicated signal in order to scanning a line one times. The CCD image sensor was used to capture image of the laser line modulated by human face. The system parameters were obtained by system calibrated calculated. The lens parameters of image part of were calibrated with machine visual image method and the triangle structure parameters were calibrated with fine wire paralleled arranged. The CCD image part and line laser indicator were set with a linear motor carry which can achieve the line laser scanning form top of the head to neck. For the nose is ledge part and the eyes are sunk part, one CCD image sensor can not obtain the completed image of laser line. In this system, two CCD image sensors were set symmetric at two sides of the laser indicator. In fact, this structure includes two laser triangle measure units. Another novel design is there laser indicators were arranged in order to reduce the scanning time for it is difficult for human to keep static for longer time. The 3D data were calculated after scanning. And further data processing include 3D coordinate refine, mesh calculate and surface show. Experiments show that this system has simply structure, high scanning speed and accurate. The scanning range covers the whole head of adult, the typical resolution is 0.5mm.

A Multi-Component Automated Laser-Origami System for Cyber-Manufacturing

NASA Astrophysics Data System (ADS)

Ko, Woo-Hyun; Srinivasa, Arun; Kumar, P. R.

2017-12-01

Cyber-manufacturing systems can be enhanced by an integrated network architecture that is easily configurable, reliable, and scalable. We consider a cyber-physical system for use in an origami-type laser-based custom manufacturing machine employing folding and cutting of sheet material to manufacture 3D objects. We have developed such a system for use in a laser-based autonomous custom manufacturing machine equipped with real-time sensing and control. The basic elements in the architecture are built around the laser processing machine. They include a sensing system to estimate the state of the workpiece, a control system determining control inputs for a laser system based on the estimated data and user’s job requests, a robotic arm manipulating the workpiece in the work space, and middleware, named Etherware, supporting the communication among the systems. We demonstrate automated 3D laser cutting and bending to fabricate a 3D product as an experimental result.

Evaluation of OH laser-induced fluorescence techniques for supersonic combustion diagnostics

NASA Technical Reports Server (NTRS)

Quagliaroli, T. M.; Laufer, G.; Krauss, R. H.; Mcdaniel, J. C., Jr.

1992-01-01

The limitations on application of dye laser and narrowband tunable KrF excimer laser systems to planar OH fluorescence measurements in supersonic combustion test facilities are examined. Included in the analysis are effects of collisional quenching, beam absorption, fluorescence trapping, and signal strengths on achievable measurement accuracy using several excitation and detection options for either of the two laser systems. Dye-based laser systems are found to be the method of choice for imaging OH concentrations less than 10 exp 15 per cu cm, while the KrF based systems provide significant reduction in measurement ambiguity for concentrations in excess of 10 exp 15 per cu cm.

Mitigation of Laser Beam Scintillation in Free-Space Optical Communication Systems Through Coherence-Reducing Optical Materials

NASA Technical Reports Server (NTRS)

Renner, Christoffer J.

2005-01-01

Free-space optical communication systems (also known as lasercom systems) offer several performance advantages over traditional radio frequency communication systems. These advantages include increased data rates and reduced operating power and system weight. One serious limiting factor in a lasercom system is Optical turbulence in Earth's atmosphere. This turbulence breaks up the laser beam used to transmit the information into multiple segments that interfere with each other when the beam is focused onto the receiver. This interference pattern at the receiver changes with time causing fluctuations in the received optical intensity (scintillation). Scintillation leads to intermittent losses of the signal and an overall reduction in the lasercom system's performance. Since scintillation is a coherent effect, reducing the spatial and temporal coherence of the laser beam will reduce the scintillation. Transmitting a laser beam through certain materials is thought to reduce its coherence. Materials that were tested included: sapphire, BK7 glass, fused silica and others. The spatial and temporal coherence of the laser beam was determined by examining the interference patterns (fringes) it formed when interacting with various interferometers and etalons.

Power beaming research at NASA

NASA Technical Reports Server (NTRS)

Rather, John D. G.

1992-01-01

NASA's current research activities to evaluate laser power beaming systems are summarized with regard to their applications of greatest interest. Key technical certainties and uncertainties pertaining to laser power beaming systems appropriate for space applications are quantified. A path of development is presented that includes maturation of key technology components for reliable laser and millimeter wave power beaming systems during the 1990s.

Off-line-locked laser diode species monitor system

NASA Technical Reports Server (NTRS)

Lee, Jamine (Inventor); Goldstein, Neil (Inventor); Richtsmeier, Steven (Inventor); Bien, Fritz (Inventor); Gersh, Michael (Inventor)

1995-01-01

An off-line-locked laser diode species monitor system includes: reference means for including at least one known species having a first absorption wavelength; a laser source for irradiating the reference means and at least one sample species having a second absorption wavelength differing from the first absorption wavelength by a predetermined amount; means for locking the wavelength of the laser source to the first wavelength of the at least one known species in the reference means; a controller for defeating the means for locking and for displacing the laser source wavelength from said first absorption wavelength by said predetermined amount to the second absorption wavelength; and a sample detector device for determining laser radiation absorption at the second wavelength transmitted through the sample to detect the presence of the at least one sample species.

Analysis of Technology for Compact Coherent Lidar

NASA Technical Reports Server (NTRS)

Amzajerdian, Farzin

1997-01-01

In view of the recent advances in the area of solid state and semiconductor lasers has created new possibilities for the development of compact and reliable coherent lidars for a wide range of applications. These applications include: Automated Rendezvous and Capture, wind shear and clear air turbulence detection, aircraft wake vortex detection, and automobile collision avoidance. The work performed by the UAH personnel under this Delivery Order, concentrated on design and analyses of a compact coherent lidar system capable of measuring range and velocity of hard targets, and providing air mass velocity data. The following is the scope of this work. a. Investigate various laser sources and optical signal detection configurations in support of a compact and lightweight coherent laser radar to be developed for precision range and velocity measurements of hard and fuzzy targets. Through interaction with MSFC engineers, the most suitable laser source and signal detection technique that can provide a reliable compact and lightweight laser radar design will be selected. b. Analyze and specify the coherent laser radar system configuration and assist with its optical and electronic design efforts. Develop a system design including its optical layout design. Specify all optical components and provide the general requirements of the electronic subsystems including laser beam modulator and demodulator drivers, detector electronic interface, and the signal processor. c. Perform a thorough performance analysis to predict the system measurement range and accuracy. This analysis will utilize various coherent laser radar sensitivity formulations and different target models.

System and Method for Generating a Frequency Modulated Linear Laser Waveform

NASA Technical Reports Server (NTRS)

Pierrottet, Diego F. (Inventor); Petway, Larry B. (Inventor); Amzajerdian, Farzin (Inventor); Barnes, Bruce W. (Inventor); Lockard, George E. (Inventor); Hines, Glenn D. (Inventor)

2017-01-01

A system for generating a frequency modulated linear laser waveform includes a single frequency laser generator to produce a laser output signal. An electro-optical modulator modulates the frequency of the laser output signal to define a linear triangular waveform. An optical circulator passes the linear triangular waveform to a band-pass optical filter to filter out harmonic frequencies created in the waveform during modulation of the laser output signal, to define a pure filtered modulated waveform having a very narrow bandwidth. The optical circulator receives the pure filtered modulated laser waveform and transmits the modulated laser waveform to a target.

System and Method for Generating a Frequency Modulated Linear Laser Waveform

NASA Technical Reports Server (NTRS)

Pierrottet, Diego F. (Inventor); Petway, Larry B. (Inventor); Amzajerdian, Farzin (Inventor); Barnes, Bruce W. (Inventor); Lockard, George E. (Inventor); Hines, Glenn D. (Inventor)

2014-01-01

A system for generating a frequency modulated linear laser waveform includes a single frequency laser generator to produce a laser output signal. An electro-optical modulator modulates the frequency of the laser output signal to define a linear triangular waveform. An optical circulator passes the linear triangular waveform to a band-pass optical filter to filter out harmonic frequencies created in the waveform during modulation of the laser output signal, to define a pure filtered modulated waveform having a very narrow bandwidth. The optical circulator receives the pure filtered modulated laser waveform and transmits the modulated laser waveform to a target.

Application of lasers and pulsed power to coating removal

NASA Astrophysics Data System (ADS)

Young, Chris M.; Moeny, William M.; Curry, Randy D.; McDonald, Ken; Bosma, John T.

1995-03-01

Lasers and other pulsed power systems are uniquely suited for removal of coatings from a wide variety of substrates. Coatings which can be removed by these systems include paint, adhesives, epoxies, dips, rust, scale, and bird droppings. Suitable substrates include wood, metal, cloth, stone, ceramic, plastics, and even skin. These systems have the advantage over chemical stripping or mechanical abrasion in that the substrate is left virtually unharmed and in many cases the residue is reduced to a form that is more easily disposed of without toxic byproducts or expensive refurbishment. Furthermore, laser and other pulsed power based systems can be operated using only local containment without the need for special operator protective gear or complete enclosure of the substrate structure. Additional advantages are gained in these systems because they typically combine multiple removal mechanisms for greater effectiveness. For example, pulsed lasers create rapid heating of the coating. This rapid heating can result in chemical breakdown of the coating, thermomechanical stress induced dislocation, shock wave agitation, and physical ablation. This paper presents some of the latest research findings on coating removal using these systems. A comparative survey of the system technology, effectiveness, cost, and application is presented. Also presented is a survey of the commercial potential for the systems. Systems which are presented include lasers (CW, pulsed, Infrared, UV, etc.), flashlamps, electro-cathodic debonders, electron beams, and glow discharges.

The simulation study on optical target laser active detection performance

NASA Astrophysics Data System (ADS)

Li, Ying-chun; Hou, Zhao-fei; Fan, Youchen

2014-12-01

According to the working principle of laser active detection system, the paper establishes the optical target laser active detection simulation system, carry out the simulation study on the detection process and detection performance of the system. For instance, the performance model such as the laser emitting, the laser propagation in the atmosphere, the reflection of optical target, the receiver detection system, the signal processing and recognition. We focus on the analysis and modeling the relationship between the laser emitting angle and defocus amount and "cat eye" effect echo laser in the reflection of optical target. Further, in the paper some performance index such as operating range, SNR and the probability of the system have been simulated. The parameters including laser emitting parameters, the reflection of the optical target and the laser propagation in the atmosphere which make a great influence on the performance of the optical target laser active detection system. Finally, using the object-oriented software design methods, the laser active detection system with the opening type, complete function and operating platform, realizes the process simulation that the detection system detect and recognize the optical target, complete the performance simulation of each subsystem, and generate the data report and the graph. It can make the laser active detection system performance models more intuitive because of the visible simulation process. The simulation data obtained from the system provide a reference to adjust the structure of the system parameters. And it provides theoretical and technical support for the top level design of the optical target laser active detection system and performance index optimization.

Modern retinal laser therapy

PubMed Central

Kozak, Igor; Luttrull, Jeffrey K.

2014-01-01

Medicinal lasers are a standard source of light to produce retinal tissue photocoagulation to treat retinovascular disease. The Diabetic Retinopathy Study and the Early Treatment Diabetic Retinopathy Study were large randomized clinical trials that have shown beneficial effect of retinal laser photocoagulation in diabetic retinopathy and have dictated the standard of care for decades. However, current treatment protocols undergo modifications. Types of lasers used in treatment of retinal diseases include argon, diode, dye and multicolor lasers, micropulse lasers and lasers for photodynamic therapy. Delivery systems include contact lens slit-lamp laser delivery, indirect ophthalmocope based laser photocoagulation and camera based navigated retinal photocoagulation with retinal eye-tracking. Selective targeted photocoagulation could be a future alternative to panretinal photocoagulation. PMID:25892934

Compact Hybrid Laser Rod and Laser System

NASA Technical Reports Server (NTRS)

Pierrottet, Diego F. (Inventor); Busch, George E. (Inventor); Amzajerdian, Farzin (Inventor)

2017-01-01

A hybrid fiber rod includes a fiber core and inner and outer cladding layers. The core is doped with an active element. The inner cladding layer surrounds the core, and has a refractive index substantially equal to that of the core. The outer cladding layer surrounds the inner cladding layer, and has a refractive index less than that of the core and inner cladding layer. The core length is about 30 to 2000 times the core diameter. A hybrid fiber rod laser system includes an oscillator laser, modulating device, the rod, and pump laser diode(s) energizing the rod from opposite ends. The rod acts as a waveguide for pump radiation but allows for free-space propagation of laser radiation. The rod may be used in a laser resonator. The core length is less than about twice the Rayleigh range. Degradation from single-mode to multi-mode beam propagation is thus avoided.

Development and Fabrication of a Space Hardened Nd(3+) YAG Laser Transmitter System for Orbital Range and Altitude Control

DTIC Science & Technology

1975-05-06

YAG system, to. be able to operate’in a ground launched satellite. ) Study was conducted to identify and eliminate all sources of laser degradation...further studies and the design of the space-hardened Laser Transmitter.I The study included such topics as general interferometer stability, internally...generated perturbances, external perturbations and their effects on the I’ laser stability. Further study covered the Laser Crystal parameters such as

Opto-mechanical system design of test system for near-infrared and visible target

NASA Astrophysics Data System (ADS)

Wang, Chunyan; Zhu, Guodong; Wang, Yuchao

2014-12-01

Guidance precision is the key indexes of the guided weapon shooting. The factors of guidance precision including: information processing precision, control system accuracy, laser irradiation accuracy and so on. The laser irradiation precision is an important factor. This paper aimed at the demand of the precision test of laser irradiator，and developed the laser precision test system. The system consists of modified cassegrain system, the wide range CCD camera, tracking turntable and industrial PC, and makes visible light and near infrared target imaging at the same time with a Near IR camera. Through the analysis of the design results, when it exposures the target of 1000 meters that the system measurement precision is43mm, fully meet the needs of the laser precision test.

Infrared laser system

DOEpatents

Cantrell, Cyrus D.; Carbone, Robert J.; Cooper, Ralph S.

1977-01-01

An infrared laser system and method for isotope separation may comprise a molecular gas laser oscillator to produce a laser beam at a first wavelength, Raman spin flip means for shifting the laser to a second wavelength, a molecular gas laser amplifier to amplify said second wavelength laser beam to high power, and optical means for directing the second wavelength, high power laser beam against a desired isotope for selective excitation thereof in a mixture with other isotopes. The optical means may include a medium which shifts the second wavelength high power laser beam to a third wavelength, high power laser beam at a wavelength coincidental with a corresponding vibrational state of said isotope and which is different from vibrational states of other isotopes in the gas mixture.

Infrared laser system

DOEpatents

Cantrell, Cyrus D.; Carbone, Robert J.; Cooper, Ralph

1982-01-01

An infrared laser system and method for isotope separation may comprise a molecular gas laser oscillator to produce a laser beam at a first wavelength, Raman spin flip means for shifting the laser to a second wavelength, a molecular gas laser amplifier to amplify said second wavelength laser beam to high power, and optical means for directing the second wavelength, high power laser beam against a desired isotope for selective excitation thereof in a mixture with other isotopes. The optical means may include a medium which shifts the second wavelength high power laser beam to a third wavelength, high power laser beam at a wavelength coincidental with a corresponding vibrational state of said isotope and which is different from vibrational states of other isotopes in the gas mixture.

Ceramic Laser Materials

PubMed Central

Sanghera, Jasbinder; Kim, Woohong; Villalobos, Guillermo; Shaw, Brandon; Baker, Colin; Frantz, Jesse; Sadowski, Bryan; Aggarwal, Ishwar

2012-01-01

Ceramic laser materials have come a long way since the first demonstration of lasing in 1964. Improvements in powder synthesis and ceramic sintering as well as novel ideas have led to notable achievements. These include the first Nd:yttrium aluminum garnet (YAG) ceramic laser in 1995, breaking the 1 KW mark in 2002 and then the remarkable demonstration of more than 100 KW output power from a YAG ceramic laser system in 2009. Additional developments have included highly doped microchip lasers, ultrashort pulse lasers, novel materials such as sesquioxides, fluoride ceramic lasers, selenide ceramic lasers in the 2 to 3 μm region, composite ceramic lasers for better thermal management, and single crystal lasers derived from polycrystalline ceramics. This paper highlights some of these notable achievements. PMID:28817044

Laser Technology in Interplanetary Exploration: The Past and the Future

NASA Technical Reports Server (NTRS)

Smith, David E.

2000-01-01

Laser technology has been used in planetary exploration for many years but it has only been in the last decade that laser altimeters and ranging systems have been selected as flight instruments alongside cameras, spectrometers, magnetometers, etc. Today we have an active laser system operating at Mars and another destined for the asteroid Eros. A few years ago a laser ranging system on the Clementine mission changed much of our thinking about the moon and in a few years laser altimeters will be on their way to Mercury, and also to Europa. Along with the increased capabilities and reliability of laser systems has came the realization that precision ranging to the surface of planetary bodies from orbiting spacecraft enables more scientific problems to be addressed, including many associated with planetary rotation, librations, and tides. In addition, new Earth-based laser ranging systems working with similar systems on other planetary bodies in an asynchronous transponder mode will be able to make interplanetary ranging measurements at the few cm level and will advance our understanding of solar system dynamics and relativistic physics.

Video Guidance Sensor System With Integrated Rangefinding

NASA Technical Reports Server (NTRS)

Book, Michael L. (Inventor); Bryan, Thomas C. (Inventor); Howard, Richard T. (Inventor); Roe, Fred Davis, Jr. (Inventor); Bell, Joseph L. (Inventor)

2006-01-01

A video guidance sensor system for use, p.g., in automated docking of a chase vehicle with a target vehicle. The system includes an integrated rangefinder sub-system that uses time of flight measurements to measure range. The rangefinder sub-system includes a pair of matched photodetectors for respectively detecting an output laser beam and return laser beam, a buffer memory for storing the photodetector outputs, and a digitizer connected to the buffer memory and including dual amplifiers and analog-to-digital converters. A digital signal processor processes the digitized output to produce a range measurement.

Laser paint removal

NASA Astrophysics Data System (ADS)

Mallets, T.

1983-12-01

The Laser Paint Stripper program is a three phase effort which includes: feasibility demonstration; prototype optimization; and implementation at our Air Logistic Centers (depots) by FY88. Major technical areas that make up the automated system include: (1) laser device with power and uptime to handle the number and size of aircraft (F-16 vs C-5A); (2) the beam transport and manipulation system; (3) controls for beam/aircraft safety, alignment, and surface condition sensors; (4) integration software; and (5) cleanup of residue products.

Mobile lidar system for environmental monitoring

NASA Astrophysics Data System (ADS)

Zhao, Guangyu; Lian, Ming; Li, Yiyun; Duan, Zheng; Zhu, Shiming; Svanberg, Sune

2018-04-01

A versatile mobile remote sensing system for multidisciplinary environmental monitoring tasks on the Chinese scene is described. The system includes a 20 Hz Nd:YAG laser-pumped dye laser, optical transmitting/receiving systems with a 30 cm and a 40 cm Newtonian telescope, and electronics, all integrated in a laboratory, installed on a Jiefang truck. Results from field experiments on atomic mercury DIAL mapping and remote laser-induced fluorescence and break-down spectroscopy are given.

Light-Directed Ranging System Implementing Single Camera System for Telerobotics Applications

NASA Technical Reports Server (NTRS)

Wells, Dennis L. (Inventor); Li, Larry C. (Inventor); Cox, Brian J. (Inventor)

1997-01-01

A laser-directed ranging system has utility for use in various fields, such as telerobotics applications and other applications involving physically handicapped individuals. The ranging system includes a single video camera and a directional light source such as a laser mounted on a camera platform, and a remotely positioned operator. In one embodiment, the position of the camera platform is controlled by three servo motors to orient the roll axis, pitch axis and yaw axis of the video cameras, based upon an operator input such as head motion. The laser is offset vertically and horizontally from the camera, and the laser/camera platform is directed by the user to point the laser and the camera toward a target device. The image produced by the video camera is processed to eliminate all background images except for the spot created by the laser. This processing is performed by creating a digital image of the target prior to illumination by the laser, and then eliminating common pixels from the subsequent digital image which includes the laser spot. A reference point is defined at a point in the video frame, which may be located outside of the image area of the camera. The disparity between the digital image of the laser spot and the reference point is calculated for use in a ranging analysis to determine range to the target.

System and method of infrared matrix-assisted laser desorption/ionization mass spectrometry in polyacrylamide gels

DOEpatents

Haglund, Jr., Richard F.; Ermer, David R.; Baltz-Knorr, Michelle Lee

2004-11-30

A system and method for desorption and ionization of analytes in an ablation medium. In one embodiment, the method includes the steps of preparing a sample having analytes in a medium including at least one component, freezing the sample at a sufficiently low temperature so that at least part of the sample has a phase transition, and irradiating the frozen sample with short-pulse radiation to cause medium ablation and desorption and ionization of the analytes. The method further includes the steps of selecting a resonant vibrational mode of at least one component of the medium and selecting an energy source tuned to emit radiation substantially at the wavelength of the selected resonant vibrational mode. The medium is an electrophoresis medium having polyacrylamide. In one embodiment, the energy source is a laser, where the laser can be a free electron laser tunable to generate short-pulse radiation. Alternatively, the laser can be a solid state laser tunable to generate short-pulse radiation. The laser can emit light at various ranges of wavelength.

Shape memory polymer (SMP) gripper with a release sensing system

DOEpatents

Maitland, Duncan J.; Lee, Abraham P.; Schumann, Daniel L.; Silva, Luiz Da

2000-01-01

A system for releasing a target material, such as an embolic coil from an SMP located at the end of a catheter utilizing an optical arrangement for releasing the material. The system includes a laser, laser driver, display panel, photodetector, fiber optics coupler, fiber optics and connectors, a catheter, and an SMP-based gripper, and includes a release sensing and feedback arrangement. The SMP-based gripper is heated via laser light through an optic fiber causing the gripper to release a target material (e.g., embolic coil for therapeutic treatment of aneurysms). Various embodiments are provided for coupling the laser light into the SMP, which includes specific positioning of the coils, removal of the fiber cladding adjacent the coil, a metal coating on the SMP, doping the SMP with a gradient absorbing dye, tapering the fiber optic end, coating the SMP with low refractive index material, and locating an insert between the fiber optic and the coil.

ICESat-2 laser technology development

NASA Astrophysics Data System (ADS)

Edwards, Ryan; Sawruk, Nick W.; Hovis, Floyd E.; Burns, Patrick; Wysocki, Theodore; Rudd, Joe; Walters, Brooke; Fakhoury, Elias; Prisciandaro, Vincent

2013-09-01

A number of ICESat-2 system requirements drove the technology evolution and the system architecture for the laser transmitter Fibertek has developed for the mission.. These requirements include the laser wall plug efficiency, laser reliability, high PRF (10kHz), short-pulse (<1.5ns), relatively narrow spectral line-width, and wave length tunability. In response to these requirements Fibertek developed a frequency-doubled, master oscillator/power amplifier (MOPA) laser that incorporates direct pumped diode pumped Nd:YVO4 as the gain media, Another guiding force in the system design has been extensive hardware life testing that Fibertek has completed. This ongoing hardware testing and development evolved the system from the original baseline brass board design to the more robust flight laser system. The final design meets or exceeds all NASA requirements and is scalable to support future mission requirements.

Free-space laser communication technologies II; Proceedings of the Meeting, Los Angeles, CA, Jan. 15-17, 1990

NASA Technical Reports Server (NTRS)

Begley, David L. (Editor); Seery, Bernard D. (Editor)

1990-01-01

Various papers on free-space laser communication technologies are presented. Individual topics addressed include: optical intersatellite link experiment between the earth station and ETS-VI, the Goddard optical communications program, technologies and techniques for lasercom terminal size, weight, and cost reduction, laser beam acquisition and tracking system for ETS-VI laser communication equipment, analog dividers for acquisition and tracking signal normalization, fine pointing mechanism using multilayered piezoelectric actuator for optical ISL system, analysis of SILEX tracking sensor performance, new telescope concept for space communication, telescope considered as a very high gain antenna, design of compact transceiver optical systems for optical intersatellite links, ultralightweight optics for laser communications, highly sensitive measurement method for stray light and retroreflected light, depolarization effects on free space laser transceiver communication systems, in-orbit measurements of microaccelerations of ESA's communication satellite Olympus, high-performance laser diode transmitter for optical free space communication, diode-pumped Nd:host laser transmitter for intersatellite optical communications, single-frequency diode-pumped laser for free-space communication.

New developments in laser-based photoemission spectroscopy and its scientific applications: a key issues review

NASA Astrophysics Data System (ADS)

Zhou, Xingjiang; He, Shaolong; Liu, Guodong; Zhao, Lin; Yu, Li; Zhang, Wentao

2018-06-01

The significant progress in angle-resolved photoemission spectroscopy (ARPES) in last three decades has elevated it from a traditional band mapping tool to a precise probe of many-body interactions and dynamics of quasiparticles in complex quantum systems. The recent developments of deep ultraviolet (DUV, including ultraviolet and vacuum ultraviolet) laser-based ARPES have further pushed this technique to a new level. In this paper, we review some latest developments in DUV laser-based photoemission systems, including the super-high energy and momentum resolution ARPES, the spin-resolved ARPES, the time-of-flight ARPES, and the time-resolved ARPES. We also highlight some scientific applications in the study of electronic structure in unconventional superconductors and topological materials using these state-of-the-art DUV laser-based ARPES. Finally we provide our perspectives on the future directions in the development of laser-based photoemission systems.

EGR distribution and fluctuation probe based on CO2 measurements

DOEpatents

Parks, II, James E.; Partridge, Jr., William P.; Yoo, Ji Hyung

2015-06-30

A diagnostic system having a laser, an EGR probe, a detector and a processor. The laser may be a swept-.lamda. laser having a sweep range including a significant CO.sub.2 feature and substantially zero absorption regions. The sweep range may extend from about 2.708 .mu.m to about 2.7085 .mu.m. The processor may determine CO.sub.2 concentration as a function of the detector output signal. The processor may normalize the output signal as a function of the zero absorption regions. The system may include a plurality of EGR probes receiving light from a single laser. The system may include a separate detector for each probe. Alternatively, the system may combine the light returning from the different probes into a composite beam that is measured by a single detector. A unique modulation characteristic may be introduced into each light beam before combination so that the processor can discriminate between them in the composite beam.

Apparatus, system, and method for laser-induced breakdown spectroscopy

DOEpatents

Effenberger, Jr., Andrew J; Scott, Jill R; McJunkin, Timothy R

2014-11-18

In laser-induced breakdown spectroscopy (LIBS), an apparatus includes a pulsed laser configured to generate a pulsed laser signal toward a sample, a constructive interference object and an optical element, each located in a path of light from the sample. The constructive interference object is configured to generate constructive interference patterns of the light. The optical element is configured to disperse the light. A LIBS system includes a first and a second optical element, and a data acquisition module. The data acquisition module is configured to determine an isotope measurement based, at least in part, on light received by an image sensor from the first and second optical elements. A method for performing LIBS includes generating a pulsed laser on a sample to generate light from a plasma, generating constructive interference patterns of the light, and dispersing the light into a plurality of wavelengths.

Microoptoelectromechanical system (MOEMS) based laser

DOEpatents

Hutchinson, Donald P.

2003-11-04

A method for forming a folded laser and associated laser device includes providing a waveguide substrate, micromachining the waveguide substrate to form a folded waveguide structure including a plurality of intersecting folded waveguide paths, forming a single fold mirror having a plurality of facets which bound all ends of said waveguide paths except those reserved for resonator mirrors, and disposing a pair of resonator mirrors on opposite sides of the waveguide to form a lasing cavity. A lasing material is provided in the lasing cavity. The laser can be sealed by disposing a top on the waveguide substrate. The laser can include a re-entrant cavity, where the waveguide substrate is disposed therein, the re-entrant cavity including the single fold mirror.

Evaluation of a satellite laser ranging technique using pseudonoise code modulated laser diodes

NASA Technical Reports Server (NTRS)

Ball, Carolyn Kay

1987-01-01

Several types of Satellite Laser Ranging systems exist, operating with pulsed, high-energy lasers. The distance between a ground point and an orbiting satellite can be determined to within a few centimeters. A new technique substitutes pseudonoise code modulated laser diodes, which are much more compact, reliable and less costly, for the lasers now used. Since laser diode technology is only now achieving sufficiently powerful lasers, the capabilities of the new technique are investigated. Also examined are the effects of using an avalanche photodiode detector instead of a photomultiplier tube. The influence of noise terms (including background radiation, detector dark and thermal noise and speckle) that limit the system range and performance is evaluated.

The selective and efficient laser ion source and trap project LIST for on-line production of exotic nuclides

NASA Astrophysics Data System (ADS)

Wendt, Klaus; Gottwald, Tina; Hanstorp, Dag; Mattolat, Christoph; Raeder, Sebastian; Rothe, Sebastian; Schwellnus, Fabio; Havener, Charles; Lassen, Jens; Liu, Yuan

2010-02-01

Laser ion sources based on resonant excitation and ionization of atoms are well-established tools for selective and efficient production of radioactive ion beams. A recent trend is the complementary installation of reliable state-of-the-art all solid-state Ti:Sapphire laser systems. To date, 35 elements of the Periodic Table are available at laser ion sources by using these novel laser systems, which complements the overall accessibility to 54 elements including use of traditional dye lasers. Recent progress in the field concerns the identification of suitable optical excitation schemes for Ti:Sapphire laser excitation as well as technical developments of the source in respect to geometry, cavity material as well as by incorporation of an ion guide system in the form of the laser ion source trap LIST.

High efficient bone ablation with diode pumped Erbium and Thulium lasers including different delivery fibers: a comparative in vitro study

NASA Astrophysics Data System (ADS)

Stock, Karl; Hausladen, Florian; Stegmayer, Thomas; Wurm, Holger

2018-02-01

Er:YAG lasers (3μm) allow efficient bone ablation caused by the strong absorption in water. Unfortunately, there are only a few and comparable expensive fiber materials for this wavelength available which are suitable for high laser power. The bone ablation efficiency of the Tm:YAG laser is minor (2μm) but inexpensive silica fibers can be used. The aim of this study was to investigate the bone ablation, using novel diode pumped high power Er:YAG (laser power 40W) and Tm:YAG laser system (60W) and adaptive fiber delivery systems. Expected advantage of these lasers is the longer lifetime of the fibers because of the high repetition rate and low pulse energy compared to the flash lamp pumped laser systems. The bare fiber output ends of a sapphire fiber (Er:YAG laser) and of a silica fiber (Tm:YAG laser) were attached under water and a water filled container including the fixed sample (bovine bone slices) was moved by a computer controlled translation stage. In a second set-up we provided a focusing unit and appropriate water spray unit. The generated cut kerfs were analyzed by light microcopy and laser scanning microscopy. The results show that with the diode pumped Er:YAG laser and sapphire fiber a particular high efficient bone ablation (> 0.16mm2/J) is possible both with bare fiber under water and focusing unit with water spray. The higher power of the Tm:YAG laser also results in high ablation rates but causes enlarged thermal damages. In conclusion, this study demonstrates that efficient bone ablation is possible with both diode pumped laser systems. In terms of efficiency the Er:YAG laser is outstanding. The Tm:YAG laser also allows fast bone ablation, provided that the thermal impact is limited by effective cooling and high movement velocity of the laser spot, for example by using an automatic scanner.

Nanodissection of human chromosomes and ultraprecise eye surgery with nanojoule near-infrared femtosecond laser pulses

NASA Astrophysics Data System (ADS)

Koenig, Karsten; Riemann, Iris; Krauss, Oliver; Fritzsche, Wolfgang

2002-04-01

Nanojoule and sub-nanojoule 80 MHz femtosecond laser pulses at 750-850 nm of a compact titanium:sapphire laser have been used for highly precise nanoprocessing of DNA as well as of intracellular and intratissue compartments. In particular, a mean power between 15 mW and 100 mW, 170 fs pulse width, submicron distance of illumination spots and microsecond beam dwell times on spots have been used for multiphoton- mediated nanoprocessing of human chromosomes, brain and ocular intrastromal tissue. By focusing the laser beam with high numerical aperture focusing optics of the laser scan system femt-O-cut and of modified multiphoton scanning microscopes to diffraction-limited spots and TW/cm2 light intensities, precise submicron holes and cuts have been processed by single spot exposure and line scans. A minimum FWHM cut size below 70 nm during the partial dissection of the human chromosome 3 was achieved. Complete chromosome dissection could be performed with FWHM cut sizes below 200 nm. Intracellular chromosome dissection was possible. Intratissue processing in depths of 50 - 100micrometers and deeper with a precision of about 1micrometers including cuts through a nuclei of a single intratissue cell without destructive photo-disruption effects to surrounding tissue layers have been demonstrated in brain and eye tissues. The femt-O-cut system includes a diagnostic system for optical tomography with submicron resolution based on multiphoton- excited autofluorescence imaging (MAI) and second harmonic generation. This system was used to localize the intracellular and intratissue targets and to control the effects of nanoprocessing. These studies show, that in contrast to conventional approaches of material processing with amplified femtosecond laser systems and (mu) J pulse energies, nanoprocessing of materials including biotissues can be performed with nJ and sub-nJ high repetition femtosecond laser pulses of turn-key compact lasers without collateral damage. Potential applications include highly precise cell and embryo surgery, gene diagnostics and gene therapy, intrastromal refractive surgery, cancer therapy and brain surgery.

Feedback stabilization system for pulsed single longitudinal mode tunable lasers

DOEpatents

Esherick, Peter; Raymond, Thomas D.

1991-10-01

A feedback stabilization system for pulse single longitudinal mode tunable lasers having an excited laser medium contained within an adjustable length cavity and producing a laser beam through the use of an internal dispersive element, including detection of angular deviation in the output laser beam resulting from detuning between the cavity mode frequency and the passband of the internal dispersive element, and generating an error signal based thereon. The error signal can be integrated and amplified and then applied as a correcting signal to a piezoelectric transducer mounted on a mirror of the laser cavity for controlling the cavity length.

Multiple pass laser amplifier system

DOEpatents

Brueckner, Keith A.; Jorna, Siebe; Moncur, N. Kent

1977-01-01

A laser amplification method for increasing the energy extraction efficiency from laser amplifiers while reducing the energy flux that passes through a flux limited system which includes apparatus for decomposing a linearly polarized light beam into multiple components, passing the components through an amplifier in delayed time sequence and recombining the amplified components into an in phase linearly polarized beam.

Method and apparatus for laser-controlled proton beam radiology

DOEpatents

Johnstone, Carol J.

1998-01-01

A proton beam radiology system provides cancer treatment and proton radiography. The system includes an accelerator for producing an H.sup.- beam and a laser source for generating a laser beam. A photodetachment module is located proximate the periphery of the accelerator. The photodetachment module combines the H.sup.- beam and laser beam to produce a neutral beam therefrom within a subsection of the H.sup.- beam. The photodetachment module emits the neutral beam along a trajectory defined by the laser beam. The photodetachment module includes a stripping foil which forms a proton beam from the neutral beam. The proton beam is delivered to a conveyance segment which transports the proton beam to a patient treatment station. The photodetachment module further includes a laser scanner which moves the laser beam along a path transverse to the cross-section of the H.sup.- beam in order to form the neutral beam in subsections of the H.sup.- beam. As the scanning laser moves across the H.sup.- beam, it similarly varies the trajectory of the proton beam emitted from the photodetachment module and in turn varies the target location of the proton beam upon the patient. Intensity modulation of the proton beam can also be achieved by controlling the output of the laser.

Method and apparatus for laser-controlled proton beam radiology

DOEpatents

Johnstone, C.J.

1998-06-02

A proton beam radiology system provides cancer treatment and proton radiography. The system includes an accelerator for producing an H{sup {minus}} beam and a laser source for generating a laser beam. A photodetachment module is located proximate the periphery of the accelerator. The photodetachment module combines the H{sup {minus}} beam and laser beam to produce a neutral beam therefrom within a subsection of the H{sup {minus}} beam. The photodetachment module emits the neutral beam along a trajectory defined by the laser beam. The photodetachment module includes a stripping foil which forms a proton beam from the neutral beam. The proton beam is delivered to a conveyance segment which transports the proton beam to a patient treatment station. The photodetachment module further includes a laser scanner which moves the laser beam along a path transverse to the cross-section of the H{sup {minus}} beam in order to form the neutral beam in subsections of the H{sup {minus}} beam. As the scanning laser moves across the H{sup {minus}} beam, it similarly varies the trajectory of the proton beam emitted from the photodetachment module and in turn varies the target location of the proton beam upon the patient. Intensity modulation of the proton beam can also be achieved by controlling the output of the laser. 9 figs.

Perspectives of using the 223-nm wavelength of the KrCl excimer laser for refractive surgery and for the treatment of some eye diseases

NASA Astrophysics Data System (ADS)

Bagayev, Sergei N.; Chernikh, Valery V.; Razhev, Alexander M.; Zhupikov, Andrey A.

2000-06-01

The new surgical UV ophthalmic laser system Medilex based on the KrCl (223 nm) excimer laser for refractive surgery was created. The comparative analysis of using the UV ophthalmic laser systems Medilex based on the ArF (193 nm) and the KrCl (223 nm) excimer lasers for the correction of refractive errors was performed. The system with the radiation wavelength of 223 nanometer of the KrCl excimer laser for refractive surgery was shown to have several medical and technical advantages over the system with the traditionally used radiation wavelength of 193 nanometer of the ArF excimer laser. In addition the use of the wavelength of 223 nanometer extends functional features of the system, allowing to make not only standard for this type systems surgical and therapeutic procedures but also to treat such ocular diseases as the glaucoma and herpetic keratities. For the UV ophthalmic laser systems Medilex three variations of the beam delivery system including special rotating masks and different beam homogenize systems were developed. All created beam delivery systems are able to make the correction of myopia, hyperopia, astigmatism and myopic or hyperopic astigmatism and may be used for therapeutic procedures. The results of the initial treatments of refractive error corrections using the UV ophthalmic laser systems Medilex for both photorefractive keratectomy (PRK) and LASIK procedures are presented.

Systems and methods for laser assisted sample transfer to solution for chemical analysis

DOEpatents

Van Berkel, Gary J.; Kertesz, Vilmos; Ovchinnikova, Olga S.

2014-06-03

Systems and methods are described for laser ablation of an analyte from a specimen and capturing of the analyte in a dispensed solvent to form a testing solution. A solvent dispensing and extraction system can form a liquid microjunction with the specimen. The solvent dispensing and extraction system can include a surface sampling probe. The laser beam can be directed through the surface sampling probe. The surface sampling probe can also serve as an atomic force microscopy probe. The surface sampling probe can form a seal with the specimen. The testing solution including the analyte can then be analyzed using an analytical instrument or undergo further processing.

Systems and methods for laser assisted sample transfer to solution for chemical analysis

DOEpatents

Van Berkel, Gary J.; Kertesz, Vilmos; Ovchinnikova, Olga S.

2015-09-29

Systems and methods are described for laser ablation of an analyte from a specimen and capturing of the analyte in a dispensed solvent to form a testing solution. A solvent dispensing and extraction system can form a liquid microjunction with the specimen. The solvent dispensing and extraction system can include a surface sampling probe. The laser beam can be directed through the surface sampling probe. The surface sampling probe can also serve as an atomic force microscopy probe. The surface sampling probe can form a seal with the specimen. The testing solution including the analyte can then be analyzed using an analytical instrument or undergo further processing.

Systems and methods for laser assisted sample transfer to solution for chemical analysis

DOEpatents

Van Berkel, Gary J; Kertesz, Vilmos; Ovchinnikova, Olga S

2013-08-27

Systems and methods are described for laser ablation of an analyte from a specimen and capturing of the analyte in a dispensed solvent to form a testing solution. A solvent dispensing and extraction system can form a liquid microjunction with the specimen. The solvent dispensing and extraction system can include a surface sampling probe. The laser beam can be directed through the surface sampling probe. The surface sampling probe can also serve as an atomic force microscopy probe. The surface sampling probe can form a seal with the specimen. The testing solution including the analyte can then be analyzed using an analytical instrument or undergo further processing.

The laser micro-machining system for diamond anvil cell experiments and general precision machining applications at the High Pressure Collaborative Access Team

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hrubiak, Rostislav; Sinogeikin, Stanislav; Rod, Eric

We have designed and constructed a new system for micro-machining parts and sample assemblies used for diamond anvil cells and general user operations at the High Pressure Collaborative Access Team, sector 16 of the Advanced Photon Source. The new micro-machining system uses a pulsed laser of 400 ps pulse duration, ablating various materials without thermal melting, thus leaving a clean edge. With optics designed for a tight focus, the system can machine holes any size larger than 3 μm in diameter. Unlike a standard electrical discharge machining drill, the new laser system allows micro-machining of non-conductive materials such as: amorphousmore » boron and silicon carbide gaskets, diamond, oxides, and other materials including organic materials such as polyimide films (i.e., Kapton). An important feature of the new system is the use of gas-tight or gas-flow environmental chambers which allow the laser micro-machining to be done in a controlled (e.g., inert gas) atmosphere to prevent oxidation and other chemical reactions in air sensitive materials. The gas-tight workpiece enclosure is also useful for machining materials with known health risks (e.g., beryllium). Specialized control software with a graphical interface enables micro-machining of custom 2D and 3D shapes. The laser-machining system was designed in a Class 1 laser enclosure, i.e., it includes laser safety interlocks and computer controls and allows for routine operation. Though initially designed mainly for machining of the diamond anvil cell gaskets, the laser-machining system has since found many other micro-machining applications, several of which are presented here.« less

A Pilot Study of Skin Resurfacing Using the 2,790-nm Erbium:YSGG Laser System.

PubMed

Rhie, Jong Won; Shim, Jeong Su; Choi, Won Seok

2015-01-01

The erbium:yttrium scandium gallium garnet (Er:YSGG) laser differs from other laser techniques by having a faster and higher cure rate. Since the Er:YSGG laser causes an appropriate proportion of ablation and coagulation, it has advantages over the conventional carbon dioxide (CO2) laser and the erbium-doped yttrium aluminum garnet (Er:YAG) laser, including heating tendencies and explosive vaporization. This research was conducted to explore the effects and safety of the Er:YSGG laser. Twenty patients participated in the pilot study of a resurfacing system using a 2,790-nm Er:YSGG laser. All patients received facial treatment by the 2,790-nm Er:YSGG laser system (Cutera) twice with a 4-week interval. Wrinkle reduction, reduction in pigment inhomogeneity, and improvement in tone and texture were measured. Study subjects included 15 women and five men. Re-epithelization occurred in all subjects 3 to 4 days after treatment, and wrinkle reduction, reduction in pigment inhomogeneity, and improvement in tone and texture within 6 months of treatment. The 2,790-nm YSGG laser technique had fewer complications and was effective in the improvement of scars, pores, wrinkles, and skin tone and color with one or two treatments. We expect this method to be effective for people with acne scars, pore scars, deep wrinkles, and uneven skin texture and color.

A Pilot Study of Skin Resurfacing Using the 2,790-nm Erbium:YSGG Laser System

PubMed Central

Rhie, Jong Won; Choi, Won Seok

2015-01-01

Background The erbium:yttrium scandium gallium garnet (Er:YSGG) laser differs from other laser techniques by having a faster and higher cure rate. Since the Er:YSGG laser causes an appropriate proportion of ablation and coagulation, it has advantages over the conventional carbon dioxide (CO2) laser and the erbium-doped yttrium aluminum garnet (Er:YAG) laser, including heating tendencies and explosive vaporization. This research was conducted to explore the effects and safety of the Er:YSGG laser. Methods Twenty patients participated in the pilot study of a resurfacing system using a 2,790-nm Er:YSGG laser. All patients received facial treatment by the 2,790-nm Er:YSGG laser system (Cutera) twice with a 4-week interval. Wrinkle reduction, reduction in pigment inhomogeneity, and improvement in tone and texture were measured. Results Study subjects included 15 women and five men. Re-epithelization occurred in all subjects 3 to 4 days after treatment, and wrinkle reduction, reduction in pigment inhomogeneity, and improvement in tone and texture within 6 months of treatment. Conclusions The 2,790-nm YSGG laser technique had fewer complications and was effective in the improvement of scars, pores, wrinkles, and skin tone and color with one or two treatments. We expect this method to be effective for people with acne scars, pore scars, deep wrinkles, and uneven skin texture and color. PMID:25606490

Method and system to measure temperature of gases using coherent anti-stokes doppler spectroscopy

DOEpatents

Rhodes, Mark

2013-12-17

A method of measuring a temperature of a noble gas in a chamber includes providing the noble gas in the chamber. The noble gas is characterized by a pressure and a temperature. The method also includes directing a first laser beam into the chamber and directing a second laser beam into the chamber. The first laser beam is characterized by a first frequency and the second laser beam is characterized by a second frequency. The method further includes converting at least a portion of the first laser beam and the second laser beam into a coherent anti-Stokes beam, measuring a Doppler broadening of the coherent anti-Stokes beam, and computing the temperature using the Doppler broadening.

An update on the use of laser technology in skin vaccination

PubMed Central

Chen, Xinyuan; Wang, Ji; Shah, Dilip; Wu, Mei X

2014-01-01

Vaccination via skin often induces stronger immune responses than via muscle. This, in line with potential needle-free, painless delivery, makes skin a very attractive site for immunization. Yet, despite decades of effort, effective skin delivery is still in its infant stage and safe and potent adjuvants for skin vaccination remain largely undefined. We have shown that laser technologies including both fractional and non-fractional lasers can greatly augment vaccine-induced immune response without incurring any significant local and systemic side effects. Laser illumination at specific settings can accelerate the motility of antigen-presenting cells or trigger release of ‘danger’ signals stimulating the immune system. Moreover, several other groups including the authors explore laser technologies for needle-free transcutaneous vaccine delivery. As these laser-mediated resurfacing technologies are convenient, safe and cost-effective, their new applications in vaccination warrant clinical studies in the very near future. PMID:24127871

Remote sensing of atmospheric pressure and sea state using laser altimeters

NASA Technical Reports Server (NTRS)

Gardner, C. S.

1985-01-01

Short-pulse multicolor laser ranging systems are currently being developed for satellite ranging applications. These systems use Q-switched pulsed lasers and streak-tube cameras to provide timing accuracies approaching a few picoseconds. Satellite laser ranging systems have been used to evaluate many important geophysical phenomena such as fault motion, polar motion and solid earth tides, by measuring the orbital perturbations of retroreflector equipped satellites. Some existing operational systems provide range resolution approaching a few millimeters. There is currently considerable interest in adapting these highly accurate systems for use as airborne and satellite based altimeters. Potential applications include the measurement of sea state, ground topography and atmospheric pressure. This paper reviews recent progress in the development of multicolor laser altimeters for use in monitoring sea state and atmospheric pressure.

Systems efficiency and specific mass estimates for direct and indirect solar-pumped closed-cycle high-energy lasers in space

NASA Technical Reports Server (NTRS)

Monson, D. J.

1978-01-01

Based on expected advances in technology, the maximum system efficiency and minimum specific mass have been calculated for closed-cycle CO and CO2 electric-discharge lasers (EDL's) and a direct solar-pumped laser in space. The efficiency calculations take into account losses from excitation gas heating, ducting frictional and turning losses, and the compressor efficiency. The mass calculations include the power source, radiator, compressor, fluids, ducting, laser channel, optics, and heat exchanger for all of the systems; and in addition the power conditioner for the EDL's and a focusing mirror for the solar-pumped laser. The results show the major component masses in each system, show which is the lightest system, and provide the necessary criteria for solar-pumped lasers to be lighter than the EDL's. Finally, the masses are compared with results from other studies for a closed-cycle CO2 gasdynamic laser (GDL) and the proposed microwave satellite solar power station (SSPS).

A Catalog of Performance Objectives and Performance Guides for Laser Systems Technician for the Job Titles of Laser Technician D.O.T. 019.181-010, Laser Systems Technician D.O.T.-N/A.

ERIC Educational Resources Information Center

Pennsylvania State Dept. of Education, Harrisburg. Bureau of Vocational and Technical Education.

This catalog lists and describes the tasks performed by a laser technician and standards for their performance. Each duty contains performance objectives for related tasks. Included in the objectives are standards that must be met and conditions for performance of the tasks. Performance guides provided for each objective identify the conditions…

Imaging laser radar for high-speed monitoring of the environment

NASA Astrophysics Data System (ADS)

Froehlich, Christoph; Mettenleiter, M.; Haertl, F.

1998-01-01

In order to establish mobile robot operations and to realize survey and inspection tasks, robust and precise measurements of the geometry of the 3D environment is the basis sensor technology. For visual inspection, surface classification, and documentation purposes, however, additional information concerning reflectance of measured objects is necessary. High-speed acquisition of both geometric and visual information is achieved by means of an active laser radar, supporting consistent range and reflectance images. The laser radar developed at Zoller + Froehlich (ZF) is an optical-wavelength system measuring the range between sensor and target surface as well as the reflectance of the target surface, which corresponds to the magnitude of the back scattered laser energy. In contrast to other range sensing devices, the ZF system is designed for high-speed and high- performance operation in real indoor and outdoor environments, emitting a minimum of near-IR laser energy. It integrates a single-point laser measurement system and a mechanical deflection system for 3D environmental measurements. This paper reports details of the laser radar which is designed to cover requirements with medium range applications. It outlines the performance requirements and introduces the two-frequency phase-shift measurement principle. The hardware design of the single-point laser measurement system, including the main modulates, such as the laser head, the high frequency unit and the signal processing unit are discussed in detail. The paper focuses on performance data of the laser radar, including noise, drift over time, precision, and accuracy with measurements. It discusses the influences of ambient light, surface material of the target, and ambient temperature for range accuracy and range precision. Furthermore, experimental results from inspection of tunnels, buildings, monuments and industrial environments are presented. The paper concludes by summarizing results and gives a short outlook to future work.

Personal medical information system using laser card

NASA Astrophysics Data System (ADS)

Cho, Seong H.; Kim, Keun Ho; Choi, Hyung-Sik; Park, Hyun Wook

1996-04-01

The well-known hospital information system (HIS) and the picture archiving and communication system (PACS) are typical applications of multimedia to medical area. This paper proposes a personal medical information save-and-carry system using a laser card. This laser card is very useful, especially in emergency situations, because the medical information in the laser card can be read at anytime and anywhere if there exists a laser card reader/writer. The contents of the laser card include the clinical histories of a patient such as clinical chart, exam result, diagnostic reports, images, and so on. The purpose of this system is not a primary diagnosis, but emergency reference of clinical history of the patient. This personal medical information system consists of a personal computer integrated with laser card reader/writer, color frame grabber, color CCD camera and a high resolution image scanner optionally. Window-based graphical user interface was designed for easy use. The laser card has relatively sufficient capacity to store the personal medical information, and has fast access speed to restore and load the data with a portable size as compact as a credit card. Database items of laser card provide the doctors with medical data such as laser card information, patient information, clinical information, and diagnostic result information.

Technology assessment of high pulse energy CO(2) lasers for remote sensing from satellites

NASA Technical Reports Server (NTRS)

Hess, R. V.; Brockman, P.; Schryer, D. R.; Miller, I. M.; Bair, C. H.; Sidney, B. D.; Wood, G. M.; Upchurch, B. T.; Brown, K. G.

1985-01-01

Developments and needs for research to extend the lifetime and optimize the configuration of CO2 laser systems for satellite based on remote sensing of atmospheric wind velocities and trace gases are reviewed. The CO2 laser systems for operational satellite application will require lifetimes which exceed 1 year. Progress in the development of efficient low temperature catalysts and gas mixture modifications for extending the lifetime of high pulse energy closed cycle common and rare isotope CO2 lasers and of sealed CW CO2 lasers is reviewed. Several CO2 laser configurations are under development to meet the requirements including: unstable resonators, master oscillator power amplifiers and telescopic stable resonators, using UV or E-beam preionization. Progress in the systems is reviewed and tradeoffs in the system parameters are discussed.

Compact DFB laser modules with integrated isolator at 935 nm

NASA Astrophysics Data System (ADS)

Reggentin, M.; Thiem, H.; Tsianos, G.; Malach, M.; Hofmann, J.; Plocke, T.; Kneier, M.; Richter, L.

2018-02-01

New developments in industrial applications and applications under rough environmental conditions within the field of spectroscopy and quantum technology in the 935 nm wavelength regime demand new compact, stable and robust laser systems. Beside a stable laser source the integration of a compact optical isolator is necessary to reduce size and power consumption for the whole laser system. The integration of a suitable optical isolator suppresses back reflections from the following optical system efficiently. However, the miniaturization of the optics inside the package leads to high optical power density levels that make a more detailed analysis of the components and their laser damage threshold necessary. We present test results on compact stable DFB laser sources (butterfly style packages) with newly integrated optical isolators operating around 935 nm. The presented data includes performance and lifetime tests for the laser diodes as well as package components. Overall performance data of the packaged laser diodes will be shown as well.

Lasers in endodontics: an overview

NASA Astrophysics Data System (ADS)

Frentzen, Matthias; Braun, Andreas; Koort, Hans J.

2002-06-01

The interest in endodontic use of dental laser systems is increasing. Developing laser technology and a better understanding of laser effects widened the spectrum of possible endodontic indications. Various laser systems including excimer-, argon+-, diode-, Nd:YAG-, Er:YAG- and CO2-lasers are used in pulp diagnosis, treatment of hypersensitivity, pulp capping, sterilization of root canals, root canal shaping and obturation or apicoectomy. With the development of new delivery systems - thin and flexible fibers - for many different wavelengths laser applications in endodontics may increase. Since laser devices are still relatively costly, access to them is limited. Most of the clinical applications are laser assisted procedures such as the removing of pulp remnants and debris or disinfection of infected root canals. The essential question is whether a laser can provide improved treatment over conventional care. To perform laser therapy in endodontics today different laser types with adopted wavelengths and pulse widths are needed, each specific to a particular application. Looking into the future we will need endodontic laser equipment providing optimal laser parameters for different treatment modalities. Nevertheless, the quantity of research reports from the last decade promises a genuine future for lasers in endodontics.

Laser heating of aqueous samples on a micro-optical-electro-mechanical system

DOEpatents

Beer, Neil Reginald; Kennedy, Ian

2013-12-17

A system of heating a sample on a microchip includes the steps of providing a microchannel flow channel in the microchip; positioning the sample within the microchannel flow channel, providing a laser that directs a laser beam onto the sample for heating the sample; providing the microchannel flow channel with a wall section that receives the laser beam and enables the laser beam to pass through wall section of the microchannel flow channel without being appreciably heated by the laser beam; and providing a carrier fluid in the microchannel flow channel that moves the sample in the microchannel flow channel wherein the carrier fluid is not appreciably heated by the laser beam.

Laser heating of aqueous samples on a micro-optical-electro-mechanical system

DOEpatents

Beer, Neil Reginald; Kennedy, Ian

2013-02-05

A system of heating a sample on a microchip includes the steps of providing a microchannel flow channel in the microchip; positioning the sample within the microchannel flow channel, providing a laser that directs a laser beam onto the sample for heating the sample; providing the microchannel flow channel with a wall section that receives the laser beam and enables the laser beam to pass through wall section of the microchannel flow channel without being appreciably heated by the laser beam; and providing a carrier fluid in the microchannel flow channel that moves the sample in the microchannel flow channel wherein the carrier fluid is not appreciably heated by the laser beam.

Multiplex electric discharge gas laser system

NASA Technical Reports Server (NTRS)

Laudenslager, James B. (Inventor); Pacala, Thomas J. (Inventor)

1987-01-01

A multiple pulse electric discharge gas laser system is described in which a plurality of pulsed electric discharge gas lasers are supported in a common housing. Each laser is supplied with excitation pulses from a separate power supply. A controller, which may be a microprocessor, is connected to each power supply for controlling the application of excitation pulses to each laser so that the lasers can be fired simultaneously or in any desired sequence. The output light beams from the individual lasers may be combined or utilized independently, depending on the desired application. The individual lasers may include multiple pairs of discharge electrodes with a separate power supply connected across each electrode pair so that multiple light output beams can be generated from a single laser tube and combined or utilized separately.

High-energy laser weapons: technology overview

NASA Astrophysics Data System (ADS)

Perram, Glen P.; Marciniak, Michael A.; Goda, Matthew

2004-09-01

High energy laser (HEL) weapons are ready for some of today"s most challenging military applications. For example, the Airborne Laser (ABL) program is designed to defend against Theater Ballistic Missiles in a tactical war scenario. Similarly, the Tactical High Energy Laser (THEL) program is currently testing a laser to defend against rockets and other tactical weapons. The Space Based Laser (SBL), Advanced Tactical Laser (ATL) and Large Aircraft Infrared Countermeasures (LAIRCM) programs promise even greater applications for laser weapons. This technology overview addresses both strategic and tactical roles for HEL weapons on the modern battlefield and examines current technology limited performance of weapon systems components, including various laser device types, beam control systems, atmospheric propagation, and target lethality issues. The characteristics, history, basic hardware, and fundamental performance of chemical lasers, solid state lasers and free electron lasers are summarized and compared. The elements of beam control, including the primary aperture, fast steering mirror, deformable mirrors, wavefront sensors, beacons and illuminators will be discussed with an emphasis on typical and required performance parameters. The effects of diffraction, atmospheric absorption, scattering, turbulence and thermal blooming phenomenon on irradiance at the target are described. Finally, lethality criteria and measures of weapon effectiveness are addressed. The primary purpose of the presentation is to define terminology, establish key performance parameters, and summarize technology capabilities.

11-kW direct diode laser system with homogenized 55 × 20 mm2 Top-Hat intensity distribution

NASA Astrophysics Data System (ADS)

Köhler, Bernd; Noeske, Axel; Kindervater, Tobias; Wessollek, Armin; Brand, Thomas; Biesenbach, Jens

2007-02-01

In comparison with other laser systems diode lasers are characterized by a unique overall efficiency, a small footprint and high reliability. However, one major drawback of direct diode laser systems is the inhomogeneous intensity distribution in the far field. Furthermore the output power of current commercially available systems is limited to about 6 kW. We report on a diode laser system with 11 kW output power at a single wavelength of 940 nm aiming for customer specific large area treatment. To the best of our knowledge this is the highest output power reported so far for a direct diode laser system. In addition to the high output power the intensity distribution of the laser beam is homogenized in both axes leading to a 55 x 20 mm2 Top-Hat intensity profile at a working distance of 400 mm. Homogeneity of the intensity distribution is better than 90%. The intensity in the focal plane is 1 kW/cm2. We will present a detailed characterization of the laser system, including measurements of power, power stability and intensity distribution of the homogenized laser beam. In addition we will compare the experimental data with the results of non-sequential raytracing simulations.

High average power laser using a transverse flowing liquid host

DOEpatents

Ault, Earl R.; Comaskey, Brian J.; Kuklo, Thomas C.

2003-07-29

A laser includes an optical cavity. A diode laser pumping device is located within the optical cavity. An aprotic lasing liquid containing neodymium rare earth ions fills the optical cavity. A circulation system that provides a closed loop for circulating the aprotic lasing liquid into and out of the optical cavity includes a pump and a heat exchanger.

Soviet chemical laser research: pulsed lasers. Report for 1963--1970

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ksander, Y.

1971-11-01

The document reviews Soviet work on pulsed chemical lasers published in the open litarature in 1963-1970. Whereas U. S. research combines the approaches of physics, quantum electrodynamics, and aerodynamics, Soviet laser research is heavily (and expertly) oriented to understanding the chemical reactions. They prefer pulsed to cw systems, concentrating on kinetics of vibrationally excited diatomic systems. The documents describe gas lasers with discharge, photolytic, and other initiation and includes research on HN/sub 3/ + CO/sub 2/ mixtures, and means of controlling reaction rates by resonant coupling and selective heating. The report also proposes a laser based on photorecombination of atoms.

CO2 lasers and applications II; Proceedings of the Third European Congress on Optics, The Hague, Netherlands, Mar. 12-14, 1990

NASA Technical Reports Server (NTRS)

Opower, Hans (Editor)

1990-01-01

Recent advances in CO2 laser technology and its applications are examined. Topics discussed include the excitation of CO2 lasers by microwave discharge, a compact RF-excited 12-kW CO2 laser, a robotic laser for three-dimensional cutting and welding, three-dimensional CO2-laser material processing with gantry machine systems, and a comparison of hollow metallic waveguides and optical fibers for transmitting CO2-laser radiation. Consideration is given to an aerodynamic window with a pump cavity and a supersonic jet, cutting and welding Al using a high-repetition-rate pulsed CO2 laser, speckle reduction in CO2 heterodyne laser radar systems, high-power-laser float-zone crystal growth, melt dynamics in surface processing with laser radiation, laser hardfacing, surface melting of AlSi10Mg with CO2 laser radiation, material processing with Cu-vapor lasers, light-induced flow at a metal surface, and absorption measurements in high-power CW CO2-laser processing of materials.

The Recovery of Optical Quality after Laser Vision Correction

PubMed Central

Jung, Hyeong-Gi

2013-01-01

Purpose To evaluate the optical quality after laser in situ keratomileusis (LASIK) or serial photorefractive keratectomy (PRK) using a double-pass system and to follow the recovery of optical quality after laser vision correction. Methods This study measured the visual acuity, manifest refraction and optical quality before and one day, one week, one month, and three months after laser vision correction. Optical quality parameters including the modulation transfer function, Strehl ratio and intraocular scattering were evaluated with a double-pass system. Results This study included 51 eyes that underwent LASIK and 57 that underwent PRK. The optical quality three months post-surgery did not differ significantly between these laser vision correction techniques. Furthermore, the preoperative and postoperative optical quality did not differ significantly in either group. Optical quality recovered within one week after LASIK but took between one and three months to recover after PRK. The optical quality of patients in the PRK group seemed to recover slightly more slowly than their uncorrected distance visual acuity. Conclusions Optical quality recovers to the preoperative level after laser vision correction, so laser vision correction is efficacious for correcting myopia. The double-pass system is a useful tool for clinical assessment of optical quality. PMID:23908570

Compact atom interferometer using single laser

NASA Astrophysics Data System (ADS)

Chiow, Sheng-Wey; Yu, Nan

2017-04-01

Atom interferometer (AI) based sensors exhibit precision and accuracy unattainable with classical sensors, thanks to the inherent stability of atomic properties. The complexity of required laser system and the size of vacuum chamber driven by optical access requirement limit the applicability of such technology in size, weight, and power (SWaP) challenging environments, such as in space. For instance, a typical physics package of AI includes six viewports for laser cooling and trapping, two for AI beams, and two more for detection and a vacuum pump. Similarly, a typical laser system for an AI includes two lasers for cooling and repumping, and two for Raman transitions as AI beam splitters. In this presentation, we report our efforts in developing a miniaturized atomic accelerometer for planetary exploration. We will describe a physics package configuration having minimum optical access (thus small volume), and a laser and optics system utilizing a single laser for the sensor operation. Preliminary results on acceleration sensitivity will be discussed. We will also illustrate a path for further packaging and integration based on the demonstrated concepts. This research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration.

A Virtual Blind Cane Using a Line Laser-Based Vision System and an Inertial Measurement Unit

PubMed Central

Dang, Quoc Khanh; Chee, Youngjoon; Pham, Duy Duong; Suh, Young Soo

2016-01-01

A virtual blind cane system for indoor application, including a camera, a line laser and an inertial measurement unit (IMU), is proposed in this paper. Working as a blind cane, the proposed system helps a blind person find the type of obstacle and the distance to it. The distance from the user to the obstacle is estimated by extracting the laser coordinate points on the obstacle, as well as tracking the system pointing angle. The paper provides a simple method to classify the obstacle’s type by analyzing the laser intersection histogram. Real experimental results are presented to show the validity and accuracy of the proposed system. PMID:26771618

Laser fusion neutron source employing compression with short pulse lasers

DOEpatents

Sefcik, Joseph A; Wilks, Scott C

2013-11-05

A method and system for achieving fusion is provided. The method includes providing laser source that generates a laser beam and a target that includes a capsule embedded in the target and filled with DT gas. The laser beam is directed at the target. The laser beam helps create an electron beam within the target. The electron beam heats the capsule, the DT gas, and the area surrounding the capsule. At a certain point equilibrium is reached. At the equilibrium point, the capsule implodes and generates enough pressure on the DT gas to ignite the DT gas and fuse the DT gas nuclei.

Self-mixing laser diode included in scanning microwave microscope to the control of probe nanodisplacement

NASA Astrophysics Data System (ADS)

Usanov, D. A.; Skripal, A. V.; Astakhov, E. I.; Dobdin, S. Y.

2018-04-01

The possibilities of self-mixing interferometry for measuring nanodisplacement of a probe included in a near-field scanning microwave microscope have been considered. The features of the formation of a laser interference signal at current modulation of the wavelength of laser radiation have been investigated. Experimental responses of a semiconductor laser system included in scanning microwave microscope to control nanodisplacement of the probe have been demonstrated.To register the nanodisplacement of the probe, it is proposed to use the method of determining the stationary phase of a laser interference signal by low-frequency spectrum of a semiconductor laser. The change of the amplitudes of the spectral components in the spectrum of the interference signal due to creation of the standing wave in the external resonator of the laser self-mixing system has been shown. The form of the interference signal at current modulation of the radiation wavelength was experimentally obtained when the probe moves with a step of 80 nm. The results of measuring nanodisplacements of an electromagnetic translator STANDA 8MVT40-13 have been demonstrated. Deviation of the nanodisplacement of the proposed method does not exceed 15%.

Spike processing with a graphene excitable laser

PubMed Central

Shastri, Bhavin J.; Nahmias, Mitchell A.; Tait, Alexander N.; Rodriguez, Alejandro W.; Wu, Ben; Prucnal, Paul R.

2016-01-01

Novel materials and devices in photonics have the potential to revolutionize optical information processing, beyond conventional binary-logic approaches. Laser systems offer a rich repertoire of useful dynamical behaviors, including the excitable dynamics also found in the time-resolved “spiking” of neurons. Spiking reconciles the expressiveness and efficiency of analog processing with the robustness and scalability of digital processing. We demonstrate a unified platform for spike processing with a graphene-coupled laser system. We show that this platform can simultaneously exhibit logic-level restoration, cascadability and input-output isolation—fundamental challenges in optical information processing. We also implement low-level spike-processing tasks that are critical for higher level processing: temporal pattern detection and stable recurrent memory. We study these properties in the context of a fiber laser system and also propose and simulate an analogous integrated device. The addition of graphene leads to a number of advantages which stem from its unique properties, including high absorption and fast carrier relaxation. These could lead to significant speed and efficiency improvements in unconventional laser processing devices, and ongoing research on graphene microfabrication promises compatibility with integrated laser platforms. PMID:26753897

Some emerging applications of lasers

NASA Astrophysics Data System (ADS)

Christensen, C. P.

1982-10-01

Applications of lasers in photochemistry, advanced instrumentation, and information storage are discussed. Laser microchemistry offers a number of new methods for altering the morphology of a solid surface with high spatial resolution. Recent experiments in material deposition, material removal, and alloying and doping are reviewed. A basic optical disk storage system is described and the problems faced by this application are discussed, in particular those pertaining to recording media. An advanced erasable system based on the magnetooptic effect is described. Applications of lasers for remote sensing are discussed, including various lidar systems, the use of laser-induced fluorescence for oil spill characterization and uranium exploration, and the use of differential absorption for detection of atmospheric constituents, temperature, and humidity.

Compensating For Movement Of Eye In Laser Surgery

NASA Technical Reports Server (NTRS)

Juday, Richard D.

1991-01-01

Conceptual system for laser surgery of retina includes subsystem that tracks position of retina. Tracking signal used to control galvanometer-driven mirrors keeping laser aimed at desired spot on retina as eye moves. Alternatively or additionally, indication of position used to prevent firing of laser when eye moved too far from proper aiming position.

Facilities to Support Beamed Energy Launch Testing at the Laser Hardened Materials Evaluation Laboratory (LHMEL)

NASA Astrophysics Data System (ADS)

Lander, Michael L.

2003-05-01

The Laser Hardened Materials Evaluation Laboratory (LHMEL) has been characterizing material responses to laser energy in support of national defense programs and the aerospace industry for the past 26 years. This paper reviews the overall resources available at LHMEL to support fundamental materials testing relating to impulse coupling measurement and to explore beamed energy launch concepts. Located at Wright-Patterson Air Force Base, Ohio, LHMEL is managed by the Air Force Research Laboratory Materials Directorate AFRL/MLPJ and operated by Anteon Corporation. The facility's advanced hardware is centered around carbon dioxide lasers producing output power up to 135kW and neodymium glass lasers producing up to 10 kilojoules of repetitively pulsed output. The specific capabilities of each laser device and related optical systems are discussed. Materials testing capabilities coupled with the laser systems are also described including laser output and test specimen response diagnostics. Environmental simulation capabilities including wind tunnels and large-volume vacuum chambers relevant to beamed energy propulsion are also discussed. This paper concludes with a summary of the procedures and methods by which the facility can be accessed.

Report on the lunar ranging at McDonald Observatory. [spark gap configuration and photomultiplier system

NASA Technical Reports Server (NTRS)

Silverberg, E. C.

1977-01-01

Range measurements to an accuracy of 5 cm were achieved following improvements in the laser oscillator configuration and the photomultiplier system. Modifications to the laser include a redesigned pockel cell mount to eliminate stressing of the cell crystal; an improved electrically triggered spark gap for sharpening the electrical pulse; the use of a brewster plate in the cavity to eliminate pre-pulsing; improved alignment for the oscillator system; and increased cavity lifetime through thin film polarizer technology. Laser calibration data are presented along with the lunar laser operations log for June to October 1977.

National Ignition Facility Laser System Performance

DOE PAGES

Spaeth, Mary L.; Manes, Kenneth R.; Bowers, M.; ...

2017-03-23

The National Ignition Facility (NIF) laser is the culmination of more than 40 years of work at Lawrence Livermore National Laboratory dedicated to the delivery of laser systems capable of driving experiments for the study of high-energy-density physics. Although NIF was designed to support a number of missions, it was clear from the beginning that its biggest challenge was to meet the requirements for pursuit of inertial confinement fusion. Meeting the Project Completion Criteria for NIF in 2009 and for the National Ignition Campaign (NIC) in 2012 included meeting the NIF Functional Requirements and Primary Criteria that were established formore » the project in 1994. Finally, during NIC and as NIF transitioned to a user facility, its goals were expanded to include requirements defined by the broader user community as well as by laser system designers and operators.« less

[The development of a distribution system for medical lasers and its clinical application].

PubMed

Okae, S; Ishiguchi, T; Ishigaki, T; Sakuma, S

1991-02-25

We developed a new laser beam generator system which can deliver laser beam to multiple terminals in distant clinical therapy rooms. The system possesses the distribution equipment by which Nd-YAG laser power is distributed to 8 output terminals under the computer control. Distributed laser beam is delivered to each distant terminal with clinical informations through the optical fiber. In the fundamental studies, possibility of distant transportation of laser beam (30 m) only with 10% loss of energy and without dangerous heating at the connection parts was shown. There seems to be no disadvantage associated with distribution laser beam. In the clinical study, the system was applied to five patients with the symptoms including hemosputum, esophageal stenosis, hemorrhage, lip ulcer and pain. Clinical usefulness of the system was proved. The advantages of the system are as follows: 1. Benefit of cost reduction due to multiple use of single laser source. 2. No necessity of transport of the equipment. 3. No requirement of a wide space to install the equipment in the distant room. 4. Efficient management and maintenance of the system by centralization. Further improvements, e.g., simultaneous use at multiple terminals and elongation of transportation up to 340 m, make the system more useful for clinical application.

Study on the high-frequency laser measurement of slot surface difference

NASA Astrophysics Data System (ADS)

Bing, Jia; Lv, Qiongying; Cao, Guohua

2017-10-01

In view of the measurement of the slot surface difference in the large-scale mechanical assembly process, Based on high frequency laser scanning technology and laser detection imaging principle, This paragraph designs a double galvanometer pulse laser scanning system. Laser probe scanning system architecture consists of three parts: laser ranging part, mechanical scanning part, data acquisition and processing part. The part of laser range uses high-frequency laser range finder to measure the distance information of the target shape and get a lot of point cloud data. Mechanical scanning part includes high-speed rotary table, high-speed transit and related structure design, in order to realize the whole system should be carried out in accordance with the design of scanning path on the target three-dimensional laser scanning. Data processing part mainly by FPGA hardware with LAbVIEW software to design a core, to process the point cloud data collected by the laser range finder at the high-speed and fitting calculation of point cloud data, to establish a three-dimensional model of the target, so laser scanning imaging is realized.

Imaging System With Confocally Self-Detecting Laser.

DOEpatents

Webb, Robert H.; Rogomentich, Fran J.

1996-10-08

The invention relates to a confocal laser imaging system and method. The system includes a laser source, a beam splitter, focusing elements, and a photosensitive detector. The laser source projects a laser beam along a first optical path at an object to be imaged, and modulates the intensity of the projected laser beam in response to light reflected from the object. A beam splitter directs a portion of the projected laser beam onto a photodetector. The photodetector monitors the intensity of laser output. The laser source can be an electrically scannable array, with a lens or objective assembly for focusing light generated by the array onto the object of interest. As the array is energized, its laser beams scan over the object, and light reflected at each point is returned by the lens to the element of the array from which it originated. A single photosensitive detector element can generate an intensity-representative signal for all lasers of the array. The intensity-representative signal from the photosensitive detector can be processed to provide an image of the object of interest.

Evaluation and design of non-lethal laser dazzlers utilizing microcontrollers

NASA Astrophysics Data System (ADS)

Richardson, Keith Jack

Current non-lethal weapons suffer from an inability to meet requirements for uses across many fields and purposes. The safety and effectiveness of these weapons are inadequate. New concepts have provided a weapon utilizing lasers to flashblind a target's visual system. Minimal research and testing have been conducted to investigate the efficiency and safety of these weapons called laser dazzlers. Essentially a laser dazzler is comprised of a laser beam that has been diverged with the use of a lens to expand the beam creating an intensely bright flashlight. All laser dazzlers to date are incapable of adjusting to external conditions automatically. This is important, because the power of these weapons need to change according to distance and light conditions. At long distances, the weapon is rendered useless because the laser beam has become diluted. At near distances, the weapon is too powerful causing permanent damage to the eye because the beam is condensed. Similarly, the eye adapts to brightness by adjusting the pupil size, which effectively limits the amount of light entering the eye. Laser eye damage is determined by the level of irradiance entering the eye. Therefore, a laser dazzler needs the ability to adjust output irradiance to compensate for the distance to the target and ambient light conditions. It was postulated if an innovative laser dazzler design could adjust the laser beam divergence then the irradiance at the eye could be optimized for maximum vision disruption with minimal risk of permanent damage. The young nature of these weapons has lead to the rushed assumptions of laser wavelengths (color) and pulsing frequencies to cause maximum disorientation. Research provided key values of irradiance, wavelength, pulsing frequency and functions for the optical lens system. In order for the laser dazzler to continuously evaluate the external conditions, luminosity and distance sensors were incorporated into the design. A control system was devised to operate the mechanical components meeting calculated values. Testing the conceptual laser dazzlers illustrated the complexities of the system. A set irradiance value could be met at any distance and light condition, although this was accomplished by less than ideal methods. The final design included two lasers and only one optical system. The optical system was only capable of providing constant irradiance of one laser or the other allowing only single laser operation. For dual laser operation, the optical system was calibrated to offset the losses of each laser as distance was changed. Ultimately, this provided a constant combined irradiance with a decreasing green irradiance and increasing red irradiance as distance was increasing. Future work should include enhancements to the mechanical components of the laser dazzler to further refine accuracy. This research was intended to provide a proof of concept and did so successfully.

Ranging Apparatus and Method Implementing Stereo Vision System

NASA Technical Reports Server (NTRS)

Li, Larry C. (Inventor); Cox, Brian J. (Inventor)

1997-01-01

A laser-directed ranging system for use in telerobotics applications and other applications involving physically handicapped individuals. The ranging system includes a left and right video camera mounted on a camera platform, and a remotely positioned operator. The position of the camera platform is controlled by three servo motors to orient the roll axis, pitch axis and yaw axis of the video cameras, based upon an operator input such as head motion. A laser is provided between the left and right video camera and is directed by the user to point to a target device. The images produced by the left and right video cameras are processed to eliminate all background images except for the spot created by the laser. This processing is performed by creating a digital image of the target prior to illumination by the laser, and then eliminating common pixels from the subsequent digital image which includes the laser spot. The horizontal disparity between the two processed images is calculated for use in a stereometric ranging analysis from which range is determined.

Compact Laser System for Field Deployable Ultracold Atom Sensors

NASA Astrophysics Data System (ADS)

Pino, Juan; Luey, Ben; Anderson, Mike

2013-05-01

As ultracold atom sensors begin to see their way to the field, there is a growing need for small, accurate, and robust laser systems to cool and manipulate atoms for sensing applications such as magnetometers, gravimeters, atomic clocks and inertial sensing. In this poster we present a laser system for Rb, roughly the size of a paperback novel, capable of generating and controlling light sufficient for the most complicated of cold atom sensors. The system includes >100dB of non-mechanical, optical shuttering, the ability to create short, microsecond pulses, a Demux stage to port light onto different optical paths, and an atomically referenced, frequency agile laser source. We will present data to support the system, its Size Weight and Power (SWaP) requirements, as well as laser stability and performance. funded under DARPA

Analytical Study on Flight Performance of a RP Laser Launcher

NASA Astrophysics Data System (ADS)

Katsurayama, H.; Ushio, M.; Komurasaki, K.; Arakawa, Y.

2005-04-01

An air-breathing RP Laser Launcher has been proposed as the alternative to conventional chemical launch systems. This paper analytically examines the feasibility of SSTO system powered by RP lasers. The trajectory from the ground to the geosynchronous orbit is computed and the launch cost including laser-base development is estimated. The engine performance is evaluated by CFD computations and a cycle analysis. The results show that the beam power of 2.3MW per unit initial vehicle mass is optimum to reach a geo-synchronous transfer orbit, and 3,000 launches are necessary to redeem the cost for laser transmitter.

Synchronized femtosecond laser pulse switching system based nano-patterning technology

NASA Astrophysics Data System (ADS)

Sohn, Ik-Bu; Choi, Hun-Kook; Yoo, Dongyoon; Noh, Young-Chul; Sung, Jae-Hee; Lee, Seong-Ku; Ahsan, Md. Shamim; Lee, Ho

2017-07-01

This paper demonstrates the design and development of a synchronized femtosecond laser pulse switching system and its applications in nano-patterning of transparent materials. Due to synchronization, we are able to control the location of each irradiated laser pulse in any kind of substrate. The control over the scanning speed and scanning step of the laser beam enables us to pattern periodic micro/nano-metric holes, voids, and/or lines in various materials. Using the synchronized laser system, we pattern synchronized nano-holes on the surface of and inside various transparent materials including fused silica glass and polymethyl methacrylate to replicate any image or pattern on the surface of or inside (transparent) materials. We also investigate the application areas of the proposed synchronized femtosecond laser pulse switching system in a diverse field of science and technology, especially in optical memory, color marking, and synchronized micro/nano-scale patterning of materials.

CO laser angioplasty system: efficacy of manipulatable laser angioscope catheter

NASA Astrophysics Data System (ADS)

Arai, Tsunenori; Kikuchi, Makoto; Mizuno, Kyoichi; Sakurada, Masami; Miyamoto, Akira; Arakawa, Koh; Kurita, Akira; Nakamura, Haruo; Takeuchi, Kiyoshi; Utsumi, Atsushi; Akai, Yoshiro

1992-08-01

A percutaneous transluminal coronary angioplasty system using a unique combination of CO laser (5 micrometers ) and As-S infrared glass fiber under the guidance of a manipulatable laser angioscope catheter is described. The ablation and guidance functions of this system are evaluated. The angioplasty treatment procedure under angioscope guidance was studied by in vitro model experiment and in vivo animal experiment. The whole angioplasty system is newly developed. That is, a transportable compact medical CO laser device which can emit up to 10 W, a 5 F manipulatable laser angioscope catheter, a thin CO laser cable of which the diameter is 0.6 mm, an angioscope imaging system for laser ablation guidance, and a system controller were developed. Anesthetized adult mongrel dogs (n equals 5) with an artificial complete occlusion in the femoral artery and an artificial human vessel model including occluded or stenotic coronary artery were used. The manipulatability of the catheter was drastically improved (both rotation and bending), therefore, precise control of ablation to expand stenosis was obtained. A 90% artificial stenosis made of human yellow plaque in 4.0 mm diameter in the vessel was expanded to 70% stenosis by repetitive CO laser ablations of which total energy was 220 J. All procedures were performed and controlled under angioscope visualization.

The Nike Laser Facility and its Capabilities

NASA Astrophysics Data System (ADS)

Serlin, V.; Aglitskiy, Y.; Chan, L. Y.; Karasik, M.; Kehne, D. M.; Oh, J.; Obenschain, S. P.; Weaver, J. L.

2013-10-01

The Nike laser is a 56-beam krypton fluoride (KrF) system that provides 3 to 4 kJ of laser energy on target. The laser uses induced spatial incoherence to achieve highly uniform focal distributions. 44 beams are overlapped onto target with peak intensities up to 1016 W/cm2. The effective time-averaged illumination nonuniformity is < 0 . 2 %. Nike produces highly uniform ablation pressures on target allowing well-controlled experiments at pressures up to 20 Mbar. The other 12 laser beams are used to generate diagnostic x-rays radiographing the primary laser-illuminated target. The facility includes a front end that generates the desired temporal and spatial laser profiles, two electron-beam pumped KrF amplifiers, a computer-controlled optical system, and a vacuum target chamber for experiments. Nike is used to study the physics and technology issues of direct-drive laser fusion, such as, hydrodynamic and laser-plasma instabilities, studies of the response of materials to extreme pressures, and generation of X rays from laser-heated targets. Nike features a computer-controlled data acquisition system, high-speed, high-resolution x-ray and visible imaging systems, x-ray and visible spectrometers, and cryogenic target capability. Work supported by DOE/NNSA.

Laser Development for Interferometry in Space

NASA Technical Reports Server (NTRS)

Numata, Kenji; Camp, Jordan

2012-01-01

We are developing a laser (master oscillator) and optical amplifier for interferometric space missions, including the gravitational-wave missions NGO and OpTIIX experiment on the international space station. Our system is based on optical fiber and semiconductor laser technologies, which have evolved dramatically in the past decade. We will report on the latest status of the development work, including noise measurements and space qualification tests.

Stimulated Brillouin scattering mirror system, high power laser and laser peening method and system using same

DOEpatents

Dane, C Brent [Livermore, CA; Hackel, Lloyd [Livermore, CA; Harris, Fritz B [Rocklin, CA

2007-04-24

A laser system, such as a master oscillator/power amplifier system, comprises a gain medium and a stimulated Brillouin scattering SBS mirror system. The SBS mirror system includes an in situ filtered SBS medium that comprises a compound having a small negative non-linear index of refraction, such as a perfluoro compound. An SBS relay telescope having a telescope focal point includes a baffle at the telescope focal point which blocks off angle beams. A beam splitter is placed between the SBS mirror system and the SBS relay telescope, directing a fraction of the beam to an alternate beam path for an alignment fiducial. The SBS mirror system has a collimated SBS cell and a focused SBS cell. An adjustable attenuator is placed between the collimated SBS cell and the focused SBS cell, by which pulse width of the reflected beam can be adjusted.

Solar-pumped lasers for space power transmission

NASA Technical Reports Server (NTRS)

Taussig, R.; Bruzzone, C.; Nelson, L.; Quimby, D.; Christiansen, W.

1979-01-01

Multi-Megawatt CW solar-pumped lasers appear to be technologically feasible for space power transmission in the 1990s time frame. A new concept for a solar-pumped laser is presented which utilizes an intermediate black body cavity to provide a uniform optical pumping environment for the lasant, either CO or CO2. Reradiation losses are minimized with resulting high efficiency operation. A 1 MW output laser may weigh as little as 8000 kg including solar collector, black body cavity, laser cavity and ducts, pumps, power systems and waste heat radiator. The efficiency of such a system will be on the order of 10 to 20%. Details of the new concept, laser design, comparison to competing solar-powered lasers and applications to a laser solar power satellite (SPS) concept are presented.

Implementing New Methods of Laser Marking of Items in the Nuclear Material Control and Accountability System at SSC RF-IPPE: An Automated Laser Marking System

DOE Office of Scientific and Technical Information (OSTI.GOV)

Regoushevsky, V I; Tambovtsev, S D; Dvukhsherstnov, V G

2009-05-18

For over ten years SSC RF-IPPE, together with the US DOE National Laboratories, has been working on implementing automated control and accountability methods for nuclear materials and other items. Initial efforts to use adhesive bar codes or ones printed (painted) onto metal revealed that these methods were inconvenient and lacked durability under operational conditions. For NM disk applications in critical stands, there is the additional requirement that labels not affect the neutron characteristics of the critical assembly. This is particularly true for the many stainless-steel clad disks containing highly enriched uranium (HEU) and plutonium that are used at SSC RF-IPPEmore » for modeling nuclear power reactors. In search of an alternate method for labeling these disks, we tested several technological options, including laser marking and two-dimensional codes. As a result, the method of laser coloring was chosen in combination with Data Matrix ECC200 symbology. To implement laser marking procedures for the HEU disks and meet all the nuclear material (NM) handling standards and rules, IPPE staff, with U.S. technical and financial support, implemented an automated laser marking system; there are also specially developed procedures for NM movements during laser marking. For the laser marking station, a Zenith 10F system by Telesis Technologies (10 watt Ytterbium Fiber Laser and Merlin software) is used. The presentation includes a flowchart for the automated system and a list of specially developed procedures with comments. Among other things, approaches are discussed for human-factor considerations. To date, markings have been applied to numerous steel-clad HEU disks, and the work continues. In the future this method is expected to be applied to other MC&A items.« less

Laser heating of aqueous samples on a micro-optical-electro-mechanical system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Beer, Neil Reginald; Kennedy, Ian

2013-12-17

A system of heating a sample on a microchip includes the steps of providing a microchannel flow channel in the microchip; positioning the sample within the microchannel flow channel, providing a laser that directs a laser beam onto the sample for heating the sample; providing the microchannel flow channel with a wall section that receives the laser beam and enables the laser beam to pass through wall section of the microchannel flow channel without being appreciably heated by the laser beam; and providing a carrier fluid in the microchannel flow channel that moves the sample in the microchannel flow channelmore » wherein the carrier fluid is not appreciably heated by the laser beam.« less

Novel atmospheric extinction measurement techniques for aerospace laser system applications

NASA Astrophysics Data System (ADS)

Sabatini, Roberto; Richardson, Mark

2013-01-01

Novel techniques for laser beam atmospheric extinction measurements, suitable for manned and unmanned aerospace vehicle applications, are presented in this paper. Extinction measurements are essential to support the engineering development and the operational employment of a variety of aerospace electro-optical sensor systems, allowing calculation of the range performance attainable with such systems in current and likely future applications. Such applications include ranging, weaponry, Earth remote sensing and possible planetary exploration missions performed by satellites and unmanned flight vehicles. Unlike traditional LIDAR methods, the proposed techniques are based on measurements of the laser energy (intensity and spatial distribution) incident on target surfaces of known geometric and reflective characteristics, by means of infrared detectors and/or infrared cameras calibrated for radiance. Various laser sources can be employed with wavelengths from the visible to the far infrared portions of the spectrum, allowing for data correlation and extended sensitivity. Errors affecting measurements performed using the proposed methods are discussed in the paper and algorithms are proposed that allow a direct determination of the atmospheric transmittance and spatial characteristics of the laser spot. These algorithms take into account a variety of linear and non-linear propagation effects. Finally, results are presented relative to some experimental activities performed to validate the proposed techniques. Particularly, data are presented relative to both ground and flight trials performed with laser systems operating in the near infrared (NIR) at λ = 1064 nm and λ = 1550 nm. This includes ground tests performed with 10 Hz and 20 kHz PRF NIR laser systems in a large variety of atmospheric conditions, and flight trials performed with a 10 Hz airborne NIR laser system installed on a TORNADO aircraft, flying up to altitudes of 22,000 ft.

Potential efficiencies of open- and closed-cycle CO, supersonic, electric-discharge lasers

NASA Technical Reports Server (NTRS)

Monson, D. J.

1976-01-01

Computed open- and closed-cycle system efficiencies (laser power output divided by electrical power input) are presented for a CW carbon monoxide, supersonic, electric-discharge laser. Closed-system results include the compressor power required to overcome stagnation pressure losses due to supersonic heat addition and a supersonic diffuser. The paper shows the effect on the system efficiencies of varying several important parameters. These parameters include: gas mixture, gas temperature, gas total temperature, gas density, total discharge energy loading, discharge efficiency, saturated gain coefficient, optical cavity size and location with respect to the discharge, and supersonic diffuser efficiency. Maximum open-cycle efficiency of 80-90% is predicted; the best closed-cycle result is 60-70%.

Phase-locked bifrequency Raman lasing in a double-Λ system

NASA Astrophysics Data System (ADS)

Alaeian, Hadiseh; Shahriar, M. S.

2018-05-01

We show that it is possible to realize simultaneous Raman lasing at two different frequencies using a double-Λ system pumped by a bifrequency field. The bifrequency Raman lasers are phase-locked to one another and the beat-frequency matches the energy difference between the two metastable ground states. Akin to a conventional Raman laser, the bifrequency Raman lasers are expected to be subluminal. As such, these are expected to be highly stable against perturbations in cavity length and have quantum noise limited linewidths that are far below that of a conventional laser. Because of these properties, the bifrequency Raman lasers may find important applications in precision metrology, including atomic interferometry and magnetometry. The phase-locked Raman laser pair also represent a manifestation of lasing without inversion, albeit in a configuration that produces a pair of nondegenerate lasers simultaneously. This feature may enable lasing without inversion in frequency regimes not accessible using previous techniques of lasing without inversion. To elucidate the behavior of this laser pair, we develop an analytical model that describes the stimulated Raman interaction in a double-Λ system using an effective two-level transition. The approximation is valid as long as the excited states adiabatically follow the ground states, as verified by numerical simulations. The effective model is used to identify the optimal operating conditions for the bifrequency Raman lasing process. This model may also prove useful in other potential applications of the double-Λ system, including generation of squeezed light and spatial solitons.

Optical air data systems and methods

NASA Technical Reports Server (NTRS)

Caldwell, Loren M. (Inventor); Tang, Shoou-Yu (Inventor); O'Brien, Martin J. (Inventor)

2009-01-01

A method for remotely sensing air outside a moving aircraft includes generating laser radiation within a swept frequency range. A portion of the laser radiation is projected from the aircraft into the air to induce scattered laser radiation. Filtered scattered laser radiation, filtered laser radiation, and unfiltered laser radiation are detected. At least one actual ratio is determined from data corresponding to the filtered scattered laser radiation and the unfiltered laser radiation. One or more air parameters are determined by correlating the actual ratio to at least one reference ratio.

Optical air data systems and methods

NASA Technical Reports Server (NTRS)

Caldwell, Loren M. (Inventor); O'Brien, Martin J. (Inventor); Tang, Shoou-Yu (Inventor)

2011-01-01

A method for remotely sensing air outside a moving aircraft includes generating laser radiation within a swept frequency range. A portion of the laser radiation is projected from the aircraft into the air to induce scattered laser radiation. Filtered scattered laser radiation, filtered laser radiation, and unfiltered laser radiation are detected. At least one actual ratio is determined from data corresponding to the filtered scattered laser radiation and the unfiltered laser radiation. One or more air parameters are determined by correlating the actual ratio to at least one reference ratio.

Single element laser beam shaper

DOEpatents

Zhang, Shukui [Yorktown, VA; Shinn, Michelle D [Newport News, VA

2005-09-13

A single lens laser beam shaper for converting laser beams from any spatial profile to a flat-top or uniform spatial profile. The laser beam shaper includes a lens having two aspheric surfaces. The beam shaper significantly simplifies the overall structure in comparison with conventional 2-element systems and therefore provides great ease in alignment and reduction of cost.

Polarization feedback laser stabilization

DOEpatents

Esherick, Peter; Owyoung, Adelbert

1988-01-01

A system for locking two Nd:YAG laser oscillators includes an optical path for feeding the output of one laser into the other with different polarizations. Elliptical polarization is incorporated into the optical path so that the change in polarization that occurs when the frequencies coincide may be detected to provide a feedback signal to control one laser relative to the other.

Insights on correlation dimension from dynamics mapping of three experimental nonlinear laser systems.

PubMed

McMahon, Christopher J; Toomey, Joshua P; Kane, Deb M

2017-01-01

We have analysed large data sets consisting of tens of thousands of time series from three Type B laser systems: a semiconductor laser in a photonic integrated chip, a semiconductor laser subject to optical feedback from a long free-space-external-cavity, and a solid-state laser subject to optical injection from a master laser. The lasers can deliver either constant, periodic, pulsed, or chaotic outputs when parameters such as the injection current and the level of external perturbation are varied. The systems represent examples of experimental nonlinear systems more generally and cover a broad range of complexity including systematically varying complexity in some regions. In this work we have introduced a new procedure for semi-automatically interrogating experimental laser system output power time series to calculate the correlation dimension (CD) using the commonly adopted Grassberger-Proccacia algorithm. The new CD procedure is called the 'minimum gradient detection algorithm'. A value of minimum gradient is returned for all time series in a data set. In some cases this can be identified as a CD, with uncertainty. Applying the new 'minimum gradient detection algorithm' CD procedure, we obtained robust measurements of the correlation dimension for many of the time series measured from each laser system. By mapping the results across an extended parameter space for operation of each laser system, we were able to confidently identify regions of low CD (CD < 3) and assign these robust values for the correlation dimension. However, in all three laser systems, we were not able to measure the correlation dimension at all parts of the parameter space. Nevertheless, by mapping the staged progress of the algorithm, we were able to broadly classify the dynamical output of the lasers at all parts of their respective parameter spaces. For two of the laser systems this included displaying regions of high-complexity chaos and dynamic noise. These high-complexity regions are differentiated from regions where the time series are dominated by technical noise. This is the first time such differentiation has been achieved using a CD analysis approach. More can be known of the CD for a system when it is interrogated in a mapping context, than from calculations using isolated time series. This has been shown for three laser systems and the approach is expected to be useful in other areas of nonlinear science where large data sets are available and need to be semi-automatically analysed to provide real dimensional information about the complex dynamics. The CD/minimum gradient algorithm measure provides additional information that complements other measures of complexity and relative complexity, such as the permutation entropy; and conventional physical measurements.

Insights on correlation dimension from dynamics mapping of three experimental nonlinear laser systems

PubMed Central

McMahon, Christopher J.; Toomey, Joshua P.

2017-01-01

Background We have analysed large data sets consisting of tens of thousands of time series from three Type B laser systems: a semiconductor laser in a photonic integrated chip, a semiconductor laser subject to optical feedback from a long free-space-external-cavity, and a solid-state laser subject to optical injection from a master laser. The lasers can deliver either constant, periodic, pulsed, or chaotic outputs when parameters such as the injection current and the level of external perturbation are varied. The systems represent examples of experimental nonlinear systems more generally and cover a broad range of complexity including systematically varying complexity in some regions. Methods In this work we have introduced a new procedure for semi-automatically interrogating experimental laser system output power time series to calculate the correlation dimension (CD) using the commonly adopted Grassberger-Proccacia algorithm. The new CD procedure is called the ‘minimum gradient detection algorithm’. A value of minimum gradient is returned for all time series in a data set. In some cases this can be identified as a CD, with uncertainty. Findings Applying the new ‘minimum gradient detection algorithm’ CD procedure, we obtained robust measurements of the correlation dimension for many of the time series measured from each laser system. By mapping the results across an extended parameter space for operation of each laser system, we were able to confidently identify regions of low CD (CD < 3) and assign these robust values for the correlation dimension. However, in all three laser systems, we were not able to measure the correlation dimension at all parts of the parameter space. Nevertheless, by mapping the staged progress of the algorithm, we were able to broadly classify the dynamical output of the lasers at all parts of their respective parameter spaces. For two of the laser systems this included displaying regions of high-complexity chaos and dynamic noise. These high-complexity regions are differentiated from regions where the time series are dominated by technical noise. This is the first time such differentiation has been achieved using a CD analysis approach. Conclusions More can be known of the CD for a system when it is interrogated in a mapping context, than from calculations using isolated time series. This has been shown for three laser systems and the approach is expected to be useful in other areas of nonlinear science where large data sets are available and need to be semi-automatically analysed to provide real dimensional information about the complex dynamics. The CD/minimum gradient algorithm measure provides additional information that complements other measures of complexity and relative complexity, such as the permutation entropy; and conventional physical measurements. PMID:28837602

The 10 micrometer transmitter

NASA Technical Reports Server (NTRS)

1976-01-01

The design, fabrication tests, and engineering model components of a 10.6 mum wideband transceiver system are reported. The effort emphasized the transmitter subsystem, including the development of the laser, the modulator driver, and included productization of both the transmitter and local oscillator lasers. The transmitter subsystem is functionally compatible with the receiver engineering model terminal, and has undergone high data rate communication system testing against that terminal.

Tunable diode-laser absorption measurements of methane at elevated temperatures

NASA Astrophysics Data System (ADS)

Nagali, V.; Chou, S. I.; Baer, D. S.; Hanson, R. K.; Segall, J.

1996-07-01

A diode-laser sensor system based on absorption spectroscopy techniques has been developed to monitor CH4 nonintrusively in high-temperature environments. Fundamental spectroscopic parameters, including the line strengths of the transitions in the R(6) manifold of the 2 nu 3 band near 1.646 mu m, have been determined from high-resolution absorption measurements in a heated static cell. In addition, a corrected expression for the CH 4 partition function has been validated experimentally over the temperature range from 400 to 915 K. Potential applications of the diode-laser sensor system include process control, combustion measurements, and atmospheric monitoring.

NASA ground-based and space-based laser ranging systems

NASA Technical Reports Server (NTRS)

Fitzmaurice, M. W.

1978-01-01

Laser ranging is expected to help unlock the mysteries of the earthquake phenomenon by producing unique results of crustal motions of the Earth. The current state of the art and future projections are presented, including principal applications and characteristics of typical systems.

Laser metrology and optic active control system for GAIA

NASA Astrophysics Data System (ADS)

D'Angelo, F.; Bonino, L.; Cesare, S.; Castorina, G.; Mottini, S.; Bertinetto, F.; Bisi, M.; Canuto, E.; Musso, F.

2017-11-01

The Laser Metrology and Optic Active Control (LM&OAC) program has been carried out under ESA contract with the purpose to design and validate a laser metrology system and an actuation mechanism to monitor and control at microarcsec level the stability of the Basic Angle (angle between the lines of sight of the two telescopes) of GAIA satellite. As part of the program, a breadboard (including some EQM elements) of the laser metrology and control system has been built and submitted to functional, performance and environmental tests. In the followings we describe the mission requirements, the system architecture, the breadboard design, and finally the performed validation tests. Conclusion and appraisals from this experience are also reported.

Modular approach to achieving the next-generation X-ray light source

NASA Astrophysics Data System (ADS)

Biedron, S. G.; Milton, S. V.; Freund, H. P.

2001-12-01

A modular approach to the next-generation light source is described. The "modules" include photocathode, radio-frequency, electron guns and their associated drive-laser systems, linear accelerators, bunch-compression systems, seed laser systems, planar undulators, two-undulator harmonic generation schemes, high-gain harmonic generation systems, nonlinear higher harmonics, and wavelength shifting. These modules will be helpful in distributing the next-generation light source to many more laboratories than the current single-pass, high-gain free-electron laser designs permit, due to both monetary and/or physical space constraints.

Preclinical investigations of articular cartilage ablation with femtosecond and pulsed infrared lasers as an alternative to microfracture surgery

NASA Astrophysics Data System (ADS)

Su, Erica; Sun, Hui; Juhasz, Tibor; Wong, Brian J. F.

2014-09-01

Microfracture surgery is a bone marrow stimulation technique for treating cartilage defects and injuries in the knee. Current methods rely on surgical skill and instrumentation. This study investigates the potential use of laser technology as an alternate means to create the microfracture holes. Lasers investigated in this study include an erbium:YAG laser (λ=2.94 μm), titanium:sapphire femtosecond laser system (λ=1700 nm), and Nd:glass femtosecond laser (λ=1053 nm). Bovine samples were ablated at fluences of 8 to 18 J/cm2 with the erbium:YAG laser, at a power of 300±15 mW with the titanium:sapphire femtosecond system, and at an energy of 3 μJ/pulse with the Nd:glass laser. Samples were digitally photographed and histological sections were taken for analysis. The erbium:YAG laser is capable of fast and efficient ablation; specimen treated with fluences of 12 and 18 J/cm2 experienced significant amounts of bone removal and minimal carbonization with saline hydration. The femtosecond laser systems successfully removed cartilage but not clinically significant amounts of bone. Precise tissue removal was possible but not to substantial depths due to limitations of the systems. With additional studies and development, the use of femtosecond laser systems to ablate bone may be achieved at clinically valuable ablation rates.

Preclinical investigations of articular cartilage ablation with femtosecond and pulsed infrared lasers as an alternative to microfracture surgery.

PubMed

Su, Erica; Sun, Hui; Juhasz, Tibor; Wong, Brian J F

2014-09-01

Microfracture surgery is a bone marrow stimulation technique for treating cartilage defects and injuriesin the knee. Current methods rely on surgical skill and instrumentation. This study investigates the potential useof laser technology as an alternate means to create the microfracture holes. Lasers investigated in this study include an erbium:YAG laser (λ = 2.94 μm), titanium:sapphire femtosecond laser system (λ = 1700 nm), and Nd:glass femtosecond laser (λ = 1053 nm). Bovine samples were ablated at fluences of 8 to 18 J∕cm2 with the erbium:YAG laser, at a power of 300 ± 15 mW with the titanium:sapphire femtosecond system, and at an energy of 3 μJ∕pulse with the Nd:glass laser. Samples were digitally photographed and histological sections were taken for analysis. The erbium:YAG laser is capable of fast and efficient ablation; specimen treated with fluences of 12 and 18 J∕cm2 experienced significant amounts of bone removal and minimal carbonization with saline hydration. The femtosecond laser systems successfully removed cartilage but not clinically significant amounts of bone. Precise tissue removal was possible but not to substantial depths due to limitations of the systems. With additional studies and development, the use of femtosecond laser systems to ablate bone may be achieved at clinically valuable ablation rates.

Laser safety research and modeling for high-energy laser systems

NASA Astrophysics Data System (ADS)

Smith, Peter A.; Montes de Oca, Cecilia I.; Kennedy, Paul K.; Keppler, Kenneth S.

2002-06-01

The Department of Defense has an increasing number of high-energy laser weapons programs with the potential to mature in the not too distant future. However, as laser systems with increasingly higher energies are developed, the difficulty of the laser safety problem increases proportionally, and presents unique safety challenges. The hazard distance for the direct beam can be in the order of thousands of miles, and radiation reflected from the target may also be hazardous over long distances. This paper details the Air Force Research Laboratory/Optical Radiation Branch (AFRL/HEDO) High-Energy Laser (HEL) safety program, which has been developed to support DOD HEL programs by providing critical capability and knowledge with respect to laser safety. The overall aim of the program is to develop and demonstrate technologies that permit safe testing, deployment and use of high-energy laser weapons. The program spans the range of applicable technologies, including evaluation of the biological effects of high-energy laser systems, development and validation of laser hazard assessment tools, and development of appropriate eye protection for those at risk.

Fixed-wavelength H2O absorption spectroscopy system enhanced by an on-board external-cavity diode laser

NASA Astrophysics Data System (ADS)

Brittelle, Mack S.; Simms, Jean M.; Sanders, Scott T.; Gord, James R.; Roy, Sukesh

2016-03-01

We describe a system designed to perform fixed-wavelength absorption spectroscopy of H2O vapor in practical combustion devices. The system includes seven wavelength-stabilized distributed feedback (WSDFB) lasers, each with a spectral accuracy of  ±1 MHz. An on-board external cavity diode laser (ECDL) that tunes 1320-1365 nm extends the capabilities of the system. Five system operation modes are described. In one mode, a sweep of the ECDL is used to monitor each WSDFB laser wavelength with an accuracy of  ±30 MHz. Demonstrations of fixed-wavelength thermometry at 10 kHz bandwidth in near-room-temperature gases are presented; one test reveals a temperature measurement error of ~0.43%.

Low Cost Multi-Sensor Robot Laser Scanning System and its Accuracy Investigations for Indoor Mapping Application

NASA Astrophysics Data System (ADS)

Chen, C.; Zou, X.; Tian, M.; Li, J.; Wu, W.; Song, Y.; Dai, W.; Yang, B.

2017-11-01

In order to solve the automation of 3D indoor mapping task, a low cost multi-sensor robot laser scanning system is proposed in this paper. The multiple-sensor robot laser scanning system includes a panorama camera, a laser scanner, and an inertial measurement unit and etc., which are calibrated and synchronized together to achieve simultaneously collection of 3D indoor data. Experiments are undertaken in a typical indoor scene and the data generated by the proposed system are compared with ground truth data collected by a TLS scanner showing an accuracy of 99.2% below 0.25 meter, which explains the applicability and precision of the system in indoor mapping applications.

Fiber laser platform for highest flexibility and reliability in industrial femtosecond micromachining: TruMicro Series 2000

NASA Astrophysics Data System (ADS)

Jansen, Florian; Kanal, Florian; Kahmann, Max; Tan, Chuong; Diekamp, Holger; Scelle, Raphael; Budnicki, Aleksander; Sutter, Dirk

2018-02-01

In this work we present an ultrafast laser system distinguished by its industry-ready reliability and its outstanding flexibility that allows for real-time process-inherent parameter. The robust system design and linear amplifier architecture make the all-fiber series TruMicro 2000 ideally suited for passive coupling to hollow-core delivery fibers. In addition to details on the laser system itself, various application examples are shown, including welding of different glasses and ablation of silicon carbide and silicon.

Ponderomotive phase plate for transmission electron microscopes

DOEpatents

Reed, Bryan W [Livermore, CA

2012-07-10

A ponderomotive phase plate system and method for controllably producing highly tunable phase contrast transfer functions in a transmission electron microscope (TEM) for high resolution and biological phase contrast imaging. The system and method includes a laser source and a beam transport system to produce a focused laser crossover as a phase plate, so that a ponderomotive potential of the focused laser crossover produces a scattering-angle-dependent phase shift in the electrons of the post-sample electron beam corresponding to a desired phase contrast transfer function.

Laser angle measurement system

NASA Technical Reports Server (NTRS)

Pond, C. R.; Texeira, P. D.; Wilbert, R. E.

1980-01-01

The design and fabrication of a laser angle measurement system is described. The instrument is a fringe counting interferometer that monitors the pitch attitude of a model in a wind tunnel. A laser source and detector are mounted above the mode. Interference fringes are generated by a small passive element on the model. The fringe count is accumulated and displayed by a processor in the wind tunnel control room. Optical and electrical schematics, system maintenance and operation procedures are included, and the results of a demonstration test are given.

Laser therapy in the treatment of urological diseases

NASA Astrophysics Data System (ADS)

Nelius, T.; de Riese, W. T.; Reiher, F.; Filleur, S.; Allhoff, E. P.

2006-02-01

Applications of lasers (light amplification by stimulated emission of radiation) in various disciplines of medicine including Urology are well developed. Urology is among the medical specialties that apply many different types of laser systems to treat a broad spectrum of clinical conditions ranging from genital, bladder and urethral tumors to the treatment of benign prostate hyperplasia (BPH), urethral strictures, and stones. The specific application of various laser systems depends on the characteristics of the laser itself, delivery media for the beams, laser-tissue interaction and the desired effect. These complex conditions require an intensive and continuous exchange of information between non-medical researchers and physicians to verify "what is currently technically possible and what is medically needed". Only this exchange can lead to the development of new laser systems. While lasers have become the treatment of choice in some conditions, they could not, despite excellent clinical results, replace conventional therapy options in others. Nonetheless, the use and the introduction of lasers of different wavelengths forces urologists to keep step with the fast developing laser technology. This paper reviews current indications for clinical laser applications relevant to urology and the advantages and disadvantages of using lasers for the management of various urological lesions.

Experimental and clinical standards, and evolution of lasers in neurosurgery.

PubMed

Devaux, B C; Roux, F X

1996-01-01

From initial experiments of ruby, argon and CO2 lasers on the nervous system so far, dramatic progress was made in delivery systems technology as well as in knowledge of laser-tissue interaction effects and hazards through various animal experiments and clinical experience. Most surgical effects of laser light on neural tissue and the central nervous system (CNS) are thermal lesions. Haemostasis, cutting and vaporization depend on laser emission parameters--wavelength, fluence and mode--and on the exposed tissues optical and thermal properties--water and haemoglobin content, thermal conductivity and specific heat. CO2 and Nd-YAG lasers have today a large place in the neurosurgical armamentarium, while new laser sources such as high power diode lasers will have one in the near future. Current applications of these lasers derive from their respective characteristics, and include CNS tumour and vascular malformation surgery, and stereotactic neurosurgery. Intracranial, spinal cord and intra-orbital meningiomas are the best lesions for laser use for haemostasis, dissection and tissue vaporization. Resection of acoustic neuromas, pituitary tumours, spinal cord neuromas, intracerebral gliomas and metastases may also benefit from lasers as accurate, haemostatic, non-contact instruments which reduce surgical trauma to the brain and eloquent structures such as brain stem and cranial nerves. Coagulative lasers (1.06 microns and 1.32 microns Nd-YAG, argon, or diode laser) will find an application for arteriovenous malformations and cavernomas. Any fiberoptic-guided laser will find a use during stereotactic neurosurgical procedures, including image-guided resection of tumours and vascular malformations and endoscopic tumour resection and cysts or entry into a ventricle. Besides these routine applications of lasers, laser interstitial thermotherapy (LITT) and photodynamic therapy (PDT) of brain tumours are still in the experimental stage. The choice of a laser in a neurosurgical operating room implies an evaluation of the laser use (applications, frequency), of the available budget and costs--including purchase, maintenance and staff training--, and material that will be necessary: unit, peripherals, safety devices and measures, training programme. Future applications of lasers in neurosurgery will come from technological advances and refined experimental applications. The availability of new wavelength, tunable, small sized and "smart" laser units, will enlarge the thermal and non-thermal interactions between laser energy and neural tissue leading to new surgical applications. Tissue photo-ablation, photohynamic therapy using second generation of photosensitizers, updated thermotherapy protocols, are current trends for further use of lasers in neurosurgery.

Ruggedized microchannel-cooled laser diode array with self-aligned microlens

DOEpatents

Freitas, Barry L.; Skidmore, Jay A.

2003-11-11

A microchannel-cooled, optically corrected, laser diode array is fabricated by mounting laser diode bars onto Si surfaces. This approach allows for the highest thermal impedance, in a ruggedized, low-cost assembly that includes passive microlens attachment without the need for lens frames. The microlensed laser diode array is usable in all solid-state laser systems that require efficient, directional, narrow bandwidth, high optical power density pump sources.

Real-time laser cladding control with variable spot size

NASA Astrophysics Data System (ADS)

Arias, J. L.; Montealegre, M. A.; Vidal, F.; Rodríguez, J.; Mann, S.; Abels, P.; Motmans, F.

2014-03-01

Laser cladding processing has been used in different industries to improve the surface properties or to reconstruct damaged pieces. In order to cover areas considerably larger than the diameter of the laser beam, successive partially overlapping tracks are deposited. With no control over the process variables this conduces to an increase of the temperature, which could decrease mechanical properties of the laser cladded material. Commonly, the process is monitored and controlled by a PC using cameras, but this control suffers from a lack of speed caused by the image processing step. The aim of this work is to design and develop a FPGA-based laser cladding control system. This system is intended to modify the laser beam power according to the melt pool width, which is measured using a CMOS camera. All the control and monitoring tasks are carried out by a FPGA, taking advantage of its abundance of resources and speed of operation. The robustness of the image processing algorithm is assessed, as well as the control system performance. Laser power is decreased as substrate temperature increases, thus maintaining a constant clad width. This FPGA-based control system is integrated in an adaptive laser cladding system, which also includes an adaptive optical system that will control the laser focus distance on the fly. The whole system will constitute an efficient instrument for part repair with complex geometries and coating selective surfaces. This will be a significant step forward into the total industrial implementation of an automated industrial laser cladding process.

A comparison of the physics of Gas Tungsten Arc Welding (GTAW), Electron Beam Welding (EBW), and Laser Beam Welding (LBW)

NASA Technical Reports Server (NTRS)

Nunes, A. C., Jr.

1985-01-01

The physics governing the applicability and limitations of gas tungsten arc (GTA), electron beam (EB), and laser beam (LB) welding are compared. An appendix on the selection of laser welding systems is included.

NASA Lidar system support and MOPA technology demonstration

NASA Technical Reports Server (NTRS)

Laughman, L. M.; Capuano, B.; Wayne, R. J.

1986-01-01

A series of lidar design and technology demonstration tasks in support of a CO2 lidar program is discussed. The first of these tasks is discussed in Section VI of this report under the heading of NASA Optical Lidar Design and it consists of detailed recommendations for the layout of a CO2 Doppler lidar incorporating then existing NASA optical components and mounts. The second phase of this work consisted of the design, development, and delivery to NASA of a novel acousto-optic laser frequency stabilization system for use with the existing NASA ring laser transmitter. The second major task in this program encompasses the design and experimental demonstration of a master oscillator-power amplifier (MOPA) laser transmitter utilizing a commercially available laser as the amplifier. The MOPA design including the low chirp master oscillator is discussed in detail. Experimental results are given for one, two and three pass amplification. The report includes operating procedures for the MOPA system.

Relay telescope including baffle, and high power laser amplifier utilizing the same

DOEpatents

Dane, C. Brent; Hackel, Lloyd; Harris, Fritz B.

2006-09-19

A laser system includes an optical path having an intracavity relay telescope with a telescope focal point for imaging an output of the gain medium between an image location at or near the gain medium and an image location at or near an output coupler for the laser system. A kinematic mount is provided within a vacuum chamber, and adapted to secure beam baffles near the telescope focal point. An access port on the vacuum chamber is adapted for allowing insertion and removal of the beam baffles. A first baffle formed using an alignment pinhole aperture is used during alignment of the laser system. A second tapered baffle replaces the alignment aperture during operation and acts as a far-field baffle in which off angle beams strike the baffle a grazing angle of incidence, reducing fluence levels at the impact areas.

NASA Space Laser Technology

NASA Technical Reports Server (NTRS)

Krainak, Michael A.

2015-01-01

Over the next two decades, the number of space based laser missions for mapping, spectroscopy, remote sensing and other scientific investigations will increase several fold. The demand for high wall-plug efficiency, low noise, narrow linewidth laser systems to meet different systems requirements that can reliably operate over the life of a mission will be high. The general trends will be for spatial quality very close to the diffraction limit, improved spectral performance, increased wall-plug efficiency and multi-beam processing. Improved spectral performance will include narrower spectral width (very near the transform limit), increased wavelength stability and or tuning (depending on application) and lasers reaching a wider range of wavelengths stretching into the mid-infrared and the near ultraviolet. We are actively developing high efficiency laser transmitter and high-sensitivity laser receiver systems that are suitable for spaceborne applications.

Satellite laser ranging work at the Goddard Space Flight Center

NASA Technical Reports Server (NTRS)

Mcgunigal, T. E.; Carrion, W. J.; Caudill, L. O.; Grant, C. R.; Johnson, T. S.; Premo, D. A.; Spadin, P. L.; Winston, G. C.

1975-01-01

Laser ranging systems, their range and accuracy capabilities, and planned improvements for future systems are discussed, the systems include one fixed and two mobile lasers ranging systems. They have demonstrated better than 10 cm accuracy both on a carefully surveyed ground range and in regular satellite ranging operations. They are capable of ranging to all currently launched retroreflector equipped satellites with the exception of Timation III. A third mobile system is discussed which will be accurate to better than 5 cm and will be capable of ranging to distant satellites such as Timation III and LAGEOS.

High data-rate atom interferometers through high recapture efficiency

DOEpatents

Biedermann, Grant; Rakholia, Akash Vrijal; McGuinness, Hayden

2015-01-27

An inertial sensing system includes a magneto-optical trap (MOT) that traps atoms within a specified trapping region. The system also includes a cooling laser that cools the trapped atoms so that the atoms remain within the specified region for a specified amount of time. The system further includes a light-pulse atom interferometer (LPAI) that performs an interferometric interrogation of the atoms to determine phase changes in the atoms. The system includes a controller that controls the timing of MOT and cooling laser operations, and controls the timing of interferometric operations to substantially recapture the atoms in the specified trapping region. The system includes a processor that determines the amount inertial movement of the inertial sensing system based on the determined phase changes in the atoms. Also, a method of inertial sensing using this inertial sensing system includes recapture of atoms within the MOT following interferometric interrogation by the LPAI.

High resolution angular sensor. [reducing ring laser gyro output quantization using phase locked loops

NASA Technical Reports Server (NTRS)

Gneses, M. I.; Berg, D. S.

1981-01-01

Specifications for the pointing stabilization system of the large space telescope were used in an investigation of the feasibility of reducing ring laser gyro output quantization to the sub-arc-second level by the use of phase locked loops and associated electronics. Systems analysis procedures are discussed and a multioscillator laser gyro model is presented along with data on the oscillator noise. It is shown that a second order closed loop can meet the measurement noise requirements when the loop gain and time constant of the loop filter are appropriately chosen. The preliminary electrical design is discussed from the standpoint of circuit tradeoff considerations. Analog, digital, and hybrid designs are given and their applicability to the high resolution sensor is examined. the electrical design choice of a system configuration is detailed. The design and operation of the various modules is considered and system block diagrams are included. Phase 1 and 2 test results using the multioscillator laser gyro are included.

A compact, inexpensive infrared laser system for continuous-wave optical stimulation of the rat prostate cavernous nerves

NASA Astrophysics Data System (ADS)

Perkins, William C.; Lagoda, Gwen A.; Burnett, Arthur L.; Fried, Nathaniel M.

2014-03-01

Optical nerve stimulation (ONS) has been commonly performed in the laboratory using high-power, pulsed, infrared (IR) lasers including Holmium:YAG, diode, and Thulium fiber lasers. However, the relatively high cost of these lasers in comparison with conventional electrical nerve stimulation (ENS) equipment may represent a significant barrier to widespread adoption of ONS. Optical stimulation of the prostate cavernous nerves (CN's) has recently been reported using lower cost, continuous-wave (CW), all-fiber-based diode lasers. This preliminary study describes further miniaturization and cost reduction of the ONS system in the form of a compact, lightweight, cordless, and inexpensive IR laser. A 140-mW, 1560-nm diode laser was integrated with a green aiming beam and delivery optics into a compact ONS system. Surface and subsurface ONS was performed in a total of 5 rats, in vivo, with measurement of an intracavernous pressure (ICP) response during CW laser irradiation for 30 s with a spot diameter of 0.7 mm. Short-term, CW ONS of the prostate CN's is feasible using a compact, inexpensive, batterypowered IR laser diode system. This ONS system may represent an alternative to ENS for laboratory studies, and with further development, a handheld option for ONS in the clinic to identify and preserve the CN's during prostate cancer surgery.

Water tunnel flow visualization using a laser

NASA Technical Reports Server (NTRS)

Beckner, C.; Curry, R. E.

1985-01-01

Laser systems for flow visualization in water tunnels (similar to the vapor screen technique used in wind tunnels) can provide two-dimensional cross-sectional views of complex flow fields. This parametric study documents the practical application of the laser-enhanced visualization (LEV) technique to water tunnel testing. Aspects of the study include laser power levels, flow seeding (using flourescent dyes and embedded particulates), model preparation, and photographic techniques. The results of this study are discussed to provide potential users with basic information to aid in the design and setup of an LEV system.

Theoretical studies of solar pumped lasers

NASA Technical Reports Server (NTRS)

Harries, Wynford L.

1990-01-01

One concept for collecting solar energy is to use large solar collectors and then use lasers as energy converters whose output beams act as transmission lines to deliver the energy to a destination. The efficiency of the process would be improved if the conversion could be done directly using solar pumped lasers, and the possibility of making such lasers is studied. There are many applications for such lasers, and these are examined. By including the applications first, the requirements for the lasers will be more evident. They are especially applicable to the Space program, and include cases where no other methods of delivering power seem possible. Using the lasers for conveying information and surveillance is also discussed. Many difficulties confront the designer of an efficient system for power conversion. These involve the nature of the solar spectrum, the method of absorbing the energy, the transfer of power into laser beams, and finally, the far field patterns of the beams. The requirements of the lasers are discussed. Specific laser configurations are discussed. The thrust is into gas laser systems, because for space applications, the laser could be large, and also the medium would be uniform and not subject to thermal stresses. Dye and solid lasers are treated briefly. For gas lasers, a chart of the various possibilities is shown, and the various families of gas lasers divided according to the mechanisms of absorbing solar radiation and of lasing. Several specific models are analyzed and evaluated. Overall conclusions for the program are summarized, and the performances of the lasers related to the requirements of various applications.

Wavefront control of high-power laser beams in the National Ignition Facility (NIF)

NASA Astrophysics Data System (ADS)

Zacharias, Richard A.; Bliss, Erlan S.; Winters, Scott; Sacks, Richard A.; Feldman, Mark; Grey, Andrew; Koch, Jeffrey A.; Stolz, Christopher J.; Toeppen, John S.; Van Atta, Lewis; Woods, Bruce W.

2000-04-01

The use of lasers as the driver for inertial confinement fusion and weapons physics experiments is based on their ability to produce high-energy short pulses in a beam with low divergence. Indeed, the focusability of high quality laser beams far exceeds alternate technologies and is a major factor in the rationale for building high power lasers for such applications. The National Ignition Facility (NIF) is a large, 192-beam, high-power laser facility under construction at the Lawrence Livermore National Laboratory for fusion and weapons physics experiments. Its uncorrected minimum focal spot size is limited by laser system aberrations. The NIF includes a Wavefront Control System to correct these aberrations to yield a focal spot small enough for its applications. Sources of aberrations to be corrected include prompt pump-induced distortions in the laser amplifiers, previous-shot thermal distortions, beam off-axis effects, and gravity, mounting, and coating-induced optic distortions. Aberrations from gas density variations and optic-manufacturing figure errors are also partially corrected. This paper provides an overview of the NIF Wavefront Control System and describes the target spot size performance improvement it affords. It describes provisions made to accommodate the NIF's high fluence (laser beam and flashlamp), large wavefront correction range, wavefront temporal bandwidth, temperature and humidity variations, cleanliness requirements, and exception handling requirements (e.g. wavefront out-of-limits conditions).

Solid state laser technology - A NASA perspective

NASA Technical Reports Server (NTRS)

Allario, F.

1985-01-01

NASA's program for developing solid-state laser technology and applying it to the Space Shuttle and Space Platform is discussed. Solid-state lasers are required to fulfill the Earth Observation System's requirements. The role of the Office of Aeronautics and Space Technology in developing a NASA tunable solid-state laser program is described. The major goals of the program involve developing a solid-state pump laser in the green, using AlGaAs array technology, pumping a Nd:YAG/SLAB crystal or glass, and fabricating a lidar system, with either a CO2 laser at 10.6 microns or a Nd:YAG laser at 1.06 microns, to measure tropospheric winds to an accuracy of + or - 1 m/s and a vertical resolution of 1 km. The procedures to be followed in order to visualize this technology plan include: (1) material development and characterization, (2) laser development, and (3) implementation of the lasers.

Accelerating the Kill Chain via Future Unmanned Aircraft

DTIC Science & Technology

2007-04-01

Controller JTRS Joint Tactical Radio System Lasercom Laser communications LDHD Low Density High Demand LEO Low Earth Orbit LGB Laser Guided Bomb...published the Unmanned Aircraft Systems Roadmap 2005 that included the terms Unmanned Aircraft System (UAS) and Unmanned Aircraft (UA). This...comprehensive publication used the term Unmanned Aircraft Systems when referring to the entire system and the term Unmanned Aircraft when referring only to the

Producing a Linear Laser System for 3d Modelimg of Small Objects

NASA Astrophysics Data System (ADS)

Amini, A. Sh.; Mozaffar, M. H.

2012-07-01

Today, three dimensional modeling of objects is considered in many applications such as documentation of ancient heritage, quality control, reverse engineering and animation In this regard, there are a variety of methods for producing three-dimensional models. In this paper, a 3D modeling system is developed based on photogrammetry method using image processing and laser line extraction from images. In this method the laser beam profile is radiated on the body of the object and with video image acquisition, and extraction of laser line from the frames, three-dimensional coordinates of the objects can be achieved. In this regard, first the design and implementation of hardware, including cameras and laser systems was conducted. Afterwards, the system was calibrated. Finally, the software of the system was implemented for three dimensional data extraction. The system was investigated for modeling a number of objects. The results showed that the system can provide benefits such as low cost, appropriate speed and acceptable accuracy in 3D modeling of objects.

The Solaris-Panoptes Global Network of Robotic Telescopes and the Borowiec Satellite Laser Ranging System for SST: A Progress Report

NASA Astrophysics Data System (ADS)

Konacki, M.; Lejba, P.; Sybilski, P.; Pawłaszek, R.; Kozłowski, S.; Suchodolski, T.; Słonina, M.; Litwicki, M.; Sybilska, A.; Rogowska, B.; Kolb, U.; Burwitz, V.; Baader, J.; Groot, P.; Bloemen, S.; Ratajczak, M.; Hełminiak, K.; Borek, R.; Chodosiewicz, P.; Chimicz, A.

We present an update on the preparation of our assets that consists of a robotic network of eight optical telescopes and a laser ranging station for regular services in the SST domain. We report the development of new optical assets that include a double telescope system, Panoptes-1AB, and a new astrograph on our Solaris-3 telescope at the Siding Spring Observatory, Australia. Progress in the software development necessary for smooth SST operation includes a web based portal and an XML Azure Queue scheduling for the network giving easy access to our sensors. Astrometry24.net our new prototype cloud service for fast astrometry, streak detection and measurement with precision and performance results is also described. In the laser domain, for more than a year, Space Research Centre Borowiec laser station has regularly tracked space debris cooperative and uncooperative targets. The efforts of the stations’ staff have been focused on the tracking of typical rocket bodies from the LEO regime. Additionally, a second independent laser system fully dedicated to SST activities is under development. It will allow for an increased pace of operation of our consortium in the global SST laser domain.

Laser-powered MHD generators for space application

NASA Technical Reports Server (NTRS)

Jalufka, N. W.

1986-01-01

Magnetohydrodynamic (MHD) energy conversion systems of the pulsed laser-supported detonation (LSD) wave, plasma MHD, and liquid-metal MHD (LMMHD) types are assessed for their potential as space-based laser-to-electrical power converters. These systems offer several advantages as energy converters relative to the present chemical, nuclear, and solar devices, including high conversion efficiency, simple design, high-temperature operation, high power density, and high reliability. Of these systems, the Brayton cycle liquid-metal MHD system appears to be the most attractive. The LMMHD technology base is well established for terrestrial applications, particularly with regard to the generator, mixer, and other system components. However, further research is required to extend this technology base to space applications and to establish the technology required to couple the laser energy into the system most efficiently. Continued research on each of the three system types is recommended.

Development, Calibration and Evaluation of a Portable and Direct Georeferenced Laser Scanning System for Kinematic 3D Mapping

NASA Astrophysics Data System (ADS)

Heinz, Erik; Eling, Christian; Wieland, Markus; Klingbeil, Lasse; Kuhlmann, Heiner

2015-12-01

In recent years, kinematic laser scanning has become increasingly popular because it offers many benefits compared to static laser scanning. The advantages include both saving of time in the georeferencing and a more favorable scanning geometry. Often mobile laser scanning systems are installed on wheeled platforms, which may not reach all parts of the object. Hence, there is an interest in the development of portable systems, which remain operational even in inaccessible areas. The development of such a portable laser scanning system is presented in this paper. It consists of a lightweight direct georeferencing unit for the position and attitude determination and a small low-cost 2D laser scanner. This setup provides advantages over existing portable systems that employ heavy and expensive 3D laser scanners in a profiling mode. A special emphasis is placed on the system calibration, i. e. the determination of the transformation between the coordinate frames of the direct georeferencing unit and the 2D laser scanner. To this end, a calibration field is used, which consists of differently orientated georeferenced planar surfaces, leading to estimates for the lever arms and boresight angles with an accuracy of mm and one-tenth of a degree. Finally, point clouds of the mobile laser scanning system are compared with georeferenced point clouds of a high-precision 3D laser scanner. Accordingly, the accuracy of the system is in the order of cm to dm. This is in good agreement with the expected accuracy, which has been derived from the error propagation of previously estimated variance components.

Polarization feedback laser stabilization

DOEpatents

Esherick, P.; Owyoung, A.

1987-09-28

A system for locking two Nd:YAG laser oscillators includes an optical path for feeding the output of one laser into the other with different polarizations. Elliptical polarization is incorporated into the optical path so that the change in polarization that occurs when the frequencies coincide may be detected to provide a feedback signal to control one laser relative to the other. 4 figs.

Out of the Lab...Into the Real World

NASA Technical Reports Server (NTRS)

1999-01-01

Big Sky Laser Technologies of Bozeman, MT is a developer of compact, ruggedized commercial and developmental laser systems, including small medical lasers and Lidars used in NASA tracking applications. Company engineers developing new laser products determined that NASA technology for detection and control of prelasing in a Q-switched laser would be of value to them in at least two of their product lines. Big Sky Laser's CFR-800 unit is based on NASA technology to which they obtained a non-exclusive patent.

High Average Power Raman Conversion in Diamond: ’Eyesafe’ Output and Fiber Laser Conversion

DTIC Science & Technology

2015-06-19

Eyesafe’ output and fiber laser conversion 5a. CONTRACT NUMBER FA2386-12-1-4055 5b. GRANT NUMBER Grant 12RSZ077_124055 5c. PROGRAM ELEMENT...generating 380 W was demonstrated using a 630 W Ybdoped fiber laser system. In each case the performance was unsaturated and limited by the available pump...converter for conventional high power laser technologies including Nd doped lasers and Yb-doped fiber lasers. Diamond’s power handling capability now

Lasers in tattoo and pigmentation control: role of the PicoSure(®) laser system.

PubMed

Torbeck, Richard; Bankowski, Richard; Henize, Sarah; Saedi, Nazanin

2016-01-01

The use of picosecond lasers to remove tattoos has greatly improved due to the long-standing outcomes of nanosecond lasers, both clinically and histologically. The first aesthetic picosecond laser available for this use was the PicoSure(®) laser system (755/532 nm). Now that a vast amount of research on its use has been conducted, we performed a comprehensive review of the literature to validate the continued application of the PicoSure(®) laser system for tattoo removal. A PubMed search was conducted using the term "picosecond" combined with "laser", "dermatology", and "laser tattoo removal". A total of 13 articles were identified, and ten of these met the inclusion criteria for this review. The majority of studies showed that picosecond lasers are an effective and safe treatment mode for the removal of tattoo pigments. Several studies also indicated potential novel applications of picosecond lasers in the removal of various tattoo pigments (eg, black, red, and yellow). Adverse effects were generally mild, such as transient hypopigmentation or blister formation, and were rarely more serious, such as scarring and/or textural change. Advancements in laser technologies and their application in cutaneous medicine have revolutionized the field of laser surgery. Computational modeling provides evidence that the optimal pulse durations for tattoo ink removal are in the picosecond domain. It is recommended that the PicoSure(®) laser system continue to be used for safe and effective tattoo removal, including for red and yellow pigments.

Active laser radar (lidar) for measurement of corresponding height and reflectance images

NASA Astrophysics Data System (ADS)

Froehlich, Christoph; Mettenleiter, M.; Haertl, F.

1997-08-01

For the survey and inspection of environmental objects, a non-tactile, robust and precise imaging of height and depth is the basis sensor technology. For visual inspection,surface classification, and documentation purposes, however, additional information concerning reflectance of measured objects is necessary. High-speed acquisition of both geometric and visual information is achieved by means of an active laser radar, supporting consistent 3D height and 2D reflectance images. The laser radar is an optical-wavelength system, and is comparable to devices built by ERIM, Odetics, and Perceptron, measuring the range between sensor and target surfaces as well as the reflectance of the target surface, which corresponds to the magnitude of the back scattered laser energy. In contrast to these range sensing devices, the laser radar under consideration is designed for high speed and precise operation in both indoor and outdoor environments, emitting a minimum of near-IR laser energy. It integrates a laser range measurement system and a mechanical deflection system for 3D environmental measurements. This paper reports on design details of the laser radar for surface inspection tasks. It outlines the performance requirements and introduces the measurement principle. The hardware design, including the main modules, such as the laser head, the high frequency unit, the laser beam deflection system, and the digital signal processing unit are discussed.the signal processing unit consists of dedicated signal processors for real-time sensor data preprocessing as well as a sensor computer for high-level image analysis and feature extraction. The paper focuses on performance data of the system, including noise, drift over time, precision, and accuracy with measurements. It discuses the influences of ambient light, surface material of the target, and ambient temperature for range accuracy and range precision. Furthermore, experimental results from inspection of buildings, monuments and industrial environments are presented. The paper concludes by summarizing results achieved in industrial environments and gives a short outlook to future work.

A model for a continuous-wave iodine laser

NASA Technical Reports Server (NTRS)

Hwang, In H.; Tabibi, Bagher M.

1990-01-01

A model for a continuous-wave (CW) iodine laser has been developed and compared with the experimental results obtained from a solar-simulator-pumped CW iodine laser. The agreement between the calculated laser power output and the experimental results is generally good for various laser parameters even when the model includes only prominent rate coefficients. The flow velocity dependence of the output power shows that the CW iodine laser cannot be achieved with a flow velocity below 1 m/s for the present solar-simulator-pumped CW iodine laser system.

Laser Scanning In Inspection

NASA Astrophysics Data System (ADS)

West, Patricia; Baker, Lionel R.

1989-03-01

This paper is a review of the applications of laser scanning in inspection. The reasons for the choice of a laser in flying spot scanning and the optical properties of a laser beam which are of value in a scanning instrument will be given. The many methods of scanning laser beams in both one and two dimensions will be described. The use of one dimensional laser scanners for automatic surface inspection for transmitting and reflective products will be covered in detail, with particular emphasis on light collection techniques. On-line inspection applications which will be mentioned include: photographic film web, metal strip products, paper web, glass sheet, car body paint surfaces and internal cylinder bores. Two dimensional laser scanning is employed in applications where increased resolution, increased depth of focus, and better contrast are required compared with conventional vidicon TV or solid state array cameras. Such examples as special microscope laser scanning systems and a TV compatible system for use in restricted areas of a nuclear reactor will be described. The technical and economic benefits and limitations of laser scanning video systems will be compared with conventional TV and CCD array devices.

Comparison between sequentional treatment with diode and alexandrite lasers versus alexandrite laser alone in the treatment of hirsutism.

PubMed

Nilforoushzadeh, Mohammad Ali; Naieni, Farahnaz Fatemi; Siadat, Amir Hossein; Rad, Leila

2011-11-01

Laser systems that are commonly used for the treatment of hirsutism include the ruby laser (694 nm), the diode laser (800 nm), the alexandrite laser (755 nm) and the Nd:YAG laser (1084 nm). The diode laser and alexandrite laser are considered effective in treatment of hirsutism in dark-skinned patients. The response of hairs to these laser systems is variable and not complete. In this study, we compared the efficacy of these two laser systems for permanent hair removal. This was a randomized, controlled clinical trial that was performed with women of the age range 15-45 years old. After obtaining informed consent, the samples were randomized into two groups using random allocation software. The first group was treated with alexandrite laser alone (four sessions, two months apart). The second group was treated sequentially with diode laser for the first two sessions and alexandrite laser for the next two sessions. Overall, 111 patients (57 patients in the alexandrite laser group and 54 patients in the sequential diode-alexandrite laser group) were evaluated. There was no significant difference regarding mean of hair reduction between the two groups during the courses of treatment. Except for the first session, there was no significant difference regarding percent of patient satisfaction between the two groups (P value >0.05). Comparison between the two groups showed no significant difference one month, three months and six months after the last treatment (P value >0.05). Regarding the results of our study, there is no significant difference between sequential treatment with diode and alexandrite lasers versus alexandrite laser alone in the treatment of hirsutism. We suggest that in further studies, the efficacy of sequential treatment with other laser systems is evaluated against single treatment methods.

Dual beam optical system for pulsed laser ablation film deposition

DOEpatents

Mashburn, D.N.

1996-09-24

A laser ablation apparatus having a laser source outputting a laser ablation beam includes an ablation chamber having a sidewall, a beam divider for dividing the laser ablation beam into two substantially equal halves, and a pair of mirrors for converging the two halves on a surface of the target from complementary angles relative to the target surface normal, thereby generating a plume of ablated material emanating from the target. 3 figs.

Dual beam optical system for pulsed laser ablation film deposition

DOEpatents

Mashburn, Douglas N.

1996-01-01

A laser ablation apparatus having a laser source outputting a laser ablation beam includes an ablation chamber having a sidewall, a beam divider for dividing the laser ablation beam into two substantially equal halves, and a pair of mirrors for converging the two halves on a surface of the target from complementary angles relative to the target surface normal, thereby generating a plume of ablated material emanating from the target.

Development and testing of laser Doppler system components for wake vortex monitoring. Volume 2: Scanner operations manual

NASA Technical Reports Server (NTRS)

Edwards, B. B.; Coffey, E. W.

1974-01-01

The theory and operation of the scanner portion of the laser Doppler system for detecting and monitoring aircraft trailing vortices in an airport environment are discussed. Schematics, wiring diagrams, component values, and operation and checkout procedures are included.

A novel fiber laser development for photoacoustic microscopy

NASA Astrophysics Data System (ADS)

Yavas, Seydi; Aytac-Kipergil, Esra; Arabul, Mustafa U.; Erkol, Hakan; Akcaalan, Onder; Eldeniz, Y. Burak; Ilday, F. Omer; Unlu, Mehmet B.

2013-03-01

Photoacoustic microscopy, as an imaging modality, has shown promising results in imaging angiogenesis and cutaneous malignancies like melanoma, revealing systemic diseases including diabetes, hypertension, tracing drug efficiency and assessment of therapy, monitoring healing processes such as wound cicatrization, brain imaging and mapping. Clinically, photoacoustic microscopy is emerging as a capable diagnostic tool. Parameters of lasers used in photoacoustic microscopy, particularly, pulse duration, energy, pulse repetition frequency, and pulse-to-pulse stability affect signal amplitude and quality, data acquisition speed and indirectly, spatial resolution. Lasers used in photoacoustic microscopy are typically Q-switched lasers, low-power laser diodes, and recently, fiber lasers. Significantly, the key parameters cannot be adjusted independently of each other, whereas microvasculature and cellular imaging, e.g., have different requirements. Here, we report an integrated fiber laser system producing nanosecond pulses, covering the spectrum from 600 nm to 1100 nm, developed specifically for photoacoustic excitation. The system comprises of Yb-doped fiber oscillator and amplifier, an acousto-optic modulator and a photonic-crystal fiber to generate supercontinuum. Complete control over the pulse train, including generation of non-uniform pulse trains, is achieved via the AOM through custom-developed field-programmable gate-array electronics. The system is unique in that all the important parameters are adjustable: pulse duration in the range of 1-3 ns, pulse energy up to 10 μJ, repetition rate from 50 kHz to 3 MHz. Different photocoustic imaging probes can be excited with the ultrabroad spectrum. The entire system is fiber-integrated; guided-beam-propagation rendersit misalignment free and largely immune to mechanical perturbations. The laser is robust, low-cost and built using readily available components.

New techniques for laser beam atmospheric extinction measurements from manned and unmanned aerospace vehicles

NASA Astrophysics Data System (ADS)

Sabatini, Roberto; Richardson, Mark

2013-03-01

Novel techniques for laser beam atmospheric extinction measurements, suitable for several air and space platform applications, are presented in this paper. Extinction measurements are essential to support the engineering development and the operational employment of a variety of aerospace electro-optical sensor systems, allowing calculation of the range performance attainable with such systems in current and likely future applications. Such applications include ranging, weaponry, Earth remote sensing and possible planetary exploration missions performed by satellites and unmanned flight vehicles. Unlike traditional LIDAR methods, the proposed techniques are based on measurements of the laser energy (intensity and spatial distribution) incident on target surfaces of known geometric and reflective characteristics, by means of infrared detectors and/or infrared cameras calibrated for radiance. Various laser sources can be employed with wavelengths from the visible to the far infrared portions of the spectrum, allowing for data correlation and extended sensitivity. Errors affecting measurements performed using the proposed methods are discussed in the paper and algorithms are proposed that allow a direct determination of the atmospheric transmittance and spatial characteristics of the laser spot. These algorithms take into account a variety of linear and non-linear propagation effects. Finally, results are presented relative to some experimental activities performed to validate the proposed techniques. Particularly, data are presented relative to both ground and flight trials performed with laser systems operating in the near infrared (NIR) at λ= 1064 nm and λ= 1550 nm. This includes ground tests performed with 10 Hz and 20 KHz PRF NIR laser systems in a large variety of atmospheric conditions, and flight trials performed with a 10 Hz airborne NIR laser system installed on a TORNADO aircraft, flying up to altitudes of 22,000 ft.

Fast Offset Laser Phase-Locking System

NASA Technical Reports Server (NTRS)

Shaddock, Daniel; Ware, Brent

2008-01-01

Figure 1 shows a simplified block diagram of an improved optoelectronic system for locking the phase of one laser to that of another laser with an adjustable offset frequency specified by the user. In comparison with prior systems, this system exhibits higher performance (including higher stability) and is much easier to use. The system is based on a field-programmable gate array (FPGA) and operates almost entirely digitally; hence, it is easily adaptable to many different systems. The system achieves phase stability of less than a microcycle. It was developed to satisfy the phase-stability requirement for a planned spaceborne gravitational-wave-detecting heterodyne laser interferometer (LISA). The system has potential terrestrial utility in communications, lidar, and other applications. The present system includes a fast phasemeter that is a companion to the microcycle-accurate one described in High-Accuracy, High-Dynamic-Range Phase-Measurement System (NPO-41927), NASA Tech Briefs, Vol. 31, No. 6 (June 2007), page 22. In the present system (as in the previously reported one), beams from the two lasers (here denoted the master and slave lasers) interfere on a photodiode. The heterodyne photodiode output is digitized and fed to the fast phasemeter, which produces suitably conditioned, low-latency analog control signals which lock the phase of the slave laser to that of the master laser. These control signals are used to drive a thermal and a piezoelectric transducer that adjust the frequency and phase of the slave-laser output. The output of the photodiode is a heterodyne signal at the difference between the frequencies of the two lasers. (The difference is currently required to be less than 20 MHz due to the Nyquist limit of the current sampling rate. We foresee few problems in doubling this limit using current equipment.) Within the phasemeter, the photodiode-output signal is digitized to 15 bits at a sampling frequency of 40 MHz by use of the same analog-to-digital converter (ADC) as that of the previously reported phasemeter. The ADC output is passed to the FPGA, wherein the signal is demodulated using a digitally generated oscillator signal at the offset locking frequency specified by the user. The demodulated signal is low-pass filtered, decimated to a sample rate of 1 MHz, then filtered again. The decimated and filtered signal is converted to an analog output by a 1 MHz, 16-bit digital-to-analog converters. After a simple low-pass filter, these analog signals drive the thermal and piezoelectric transducers of the laser.

LASER Tech Briefs, February 1995. Volume 3, No. 1

NASA Technical Reports Server (NTRS)

1995-01-01

Topics included in this issue of LASER Tech Briefs are: Electronic Components and Circuits. Electronic Systems, Physical Sciences, Materials, Mechanics, Fabrication, and Mathematics and Information Sciences, and

Systems and methods for imaging using radiation from laser produced plasmas

DOEpatents

Renard-Le Galloudec, Nathalie; Cowan, Thomas E.; Sentoku, Yasuhiko; Rassuchine, Jennifer

2009-06-30

In particular embodiments, the present disclosure provides systems and methods for imaging a subject using radiation emitted from a laser produced plasma generating by irradiating a target with a laser. In particular examples, the target includes at least one radiation enhancing component, such as a fluor, cap, or wire. In further examples, the target has a metal layer and an internal surface defining an internal apex, the internal apex of less than about 15 .mu.m, such as less than about 1 .mu.m. The targets may take a variety of shapes, including cones, pyramids, and hemispheres. Certain aspects of the present disclosure provide improved imaging of a subject, such as improved medical images of a radiation dose than typical conventional methods and systems.

Laser Development for Gravitational-Wave Interferometry in Space

NASA Technical Reports Server (NTRS)

Numata, Kenji; Camp, Jordan

2012-01-01

We are reporting on our development work on laser (master oscillator) and optical amplifier systems for gravitational-wave interferometry in space. Our system is based on the mature, wave-guided optics technologies, which have advantages over bulk, crystal-based, free-space optics. We are investing in a new type of compact, low-noise master oscillator, called the planar-waveguide external cavity diode laser. We made measurements, including those of noise, and performed space-qualification tests.

Laser Opto-Electronic Correlator for Robotic Vision Automated Pattern Recognition

NASA Technical Reports Server (NTRS)

Marzwell, Neville

1995-01-01

A compact laser opto-electronic correlator for pattern recognition has been designed, fabricated, and tested. Specifically it is a translation sensitivity adjustable compact optical correlator (TSACOC) utilizing convergent laser beams for the holographic filter. Its properties and performance, including the location of the correlation peak and the effects of lateral and longitudinal displacements for both filters and input images, are systematically analyzed based on the nonparaxial approximation for the reference beam. The theoretical analyses have been verified in experiments. In applying the TSACOC to important practical problems including fingerprint identification, we have found that the tolerance of the system to the input lateral displacement can be conveniently increased by changing a geometric factor of the system. The system can be compactly packaged using the miniature laser diode sources and can be used in space by the National Aeronautics and Space Administration (NASA) and ground commercial applications which include robotic vision, and industrial inspection of automated quality control operations. The personnel of Standard International will work closely with the Jet Propulsion Laboratory (JPL) to transfer the technology to the commercial market. Prototype systems will be fabricated to test the market and perfect the product. Large production will follow after successful results are achieved.

Inhibited-coupling HC-PCF based beam-delivery-system for high power green industrial lasers

NASA Astrophysics Data System (ADS)

Chafer, M.; Gorse, A.; Beaudou, B.; Lekiefs, Q.; Maurel, M.; Debord, B.; Gérôme, F.; Benabid, F.

2018-02-01

We report on an ultra-low loss Hollow-Core Photonic Crystal Fiber (HC-PCF) beam delivery system (GLO-GreenBDS) for high power ultra-short pulse lasers operating in the green spectral range (including 515 nm and 532 nm). The GLOBDS- Green combines ease-of-use, high laser-coupling efficiency, robustness and industrial compatible cabling. It comprises a pre-aligned laser-injection head, a sheath-cable protected HC-PCF and a modular fiber-output head. It enables fiber-core gas loading and evacuation in a hermetic fashion. A 5 m long GLO-BDS were demonstrated for a green short pulse laser with a transmission coefficient larger than 80%, and a laser output profile close to single-mode (M2 <1.3).

Intense laser beams; Proceedings of the Meeting, Los Angeles, CA, Jan. 23, 24, 1992

NASA Technical Reports Server (NTRS)

Wade, Richard C. (Editor); Ulrich, Peter B. (Editor)

1992-01-01

Various papers on intense laser beams are presented. Individual topics addressed include: novel methods of copper vapor laser excitation, UCLA IR FEL, lasing characteristics of a large-bore copper vapor laser (CVL), copper density measurement of a large-bore CVL, high-power XeCl excimer laser, solid state direct-drive circuit for pumping gas lasers, united energy model for FELs, intensity and frequency instabilities in double-mode CO2 lasers, comparison of output power stabilities of CO and CO2 lasers, increasing efficiency of sealed-off CO lasers, thermal effects in singlet delta oxygen generation, optical extraction from the chemical oxygen-iodine laser medium, generation and laser diagnostic analysis of bismuth fluoride. Also discussed are: high-Q resonator design for an HF overtone chemical lasers, improved coatings for HF overtone lasers, scaled atmospheric blooming experiment, simulation on producing conjugate field using deformable mirrors, paraxial theory of amplitude correction, potential capabilities of adaptive optical systems in the atmosphere, power beaming research at NASA, system evaluations of laser power beaming options, performance projections for laser beam power to space, independent assessment of laser power beaming options, removal of atmospheric CFCs by lasers, efficiency of vaporization cutting by CVL.

Long-Term Outcomes of Laser Prostatectomy for Storage Symptoms: Comparison of Serial 5-Year Followup Data between High Performance System Photoselective Vaporization and Holmium Laser Enucleation of the Prostate.

PubMed

Cho, Min Chul; Song, Won Hoon; Park, Juhyun; Cho, Sung Yong; Jeong, Hyeon; Oh, Seung-June; Paick, Jae-Seung; Son, Hwancheol

2018-06-01

We compared long-term storage symptom outcomes between photoselective laser vaporization of the prostate with a 120 W high performance system and holmium laser enucleation of the prostate. We also determined factors influencing postoperative improvement of storage symptoms in the long term. Included in our study were 266 men, including 165 treated with prostate photoselective laser vaporization using a 120 W high performance system and 101 treated with holmium laser enucleation of the prostate, on whom 60-month followup data were available. Outcomes were assessed serially 6, 12, 24, 36, 48 and 60 months postoperatively using the International Prostate Symptom Score, uroflowmetry and the serum prostate specific antigen level. Postoperative improvement in storage symptoms was defined as a 50% or greater reduction in the subtotal storage symptom score at each followup visit after surgery compared to baseline. Improvements in frequency, urgency, nocturia, subtotal storage symptom scores and the quality of life index were maintained up to 60 months after photoselective laser vaporization or holmium laser enucleation of the prostate. There was no difference in the degree of improvement in storage symptoms or the percent of patients with postoperative improvement in storage symptoms between the 2 groups throughout the long-term followup. However, the holmium laser group showed greater improvement in voiding symptoms and quality of life than the laser vaporization group. On logistic regression analysis a higher baseline subtotal storage symptom score and a higher BOOI (Bladder Outlet Obstruction Index) were the factors influencing the improvement in storage symptoms 5 years after prostate photoselective laser vaporization or holmium laser enucleation. Our serial followup data suggest that storage symptom improvement was maintained throughout the long-term postoperative period for prostate photoselective laser vaporization with a 120 W high performance system and holmium laser enucleation without any difference between the 2 surgeries. Also, more severe storage symptoms at baseline and a more severe BOOI predicted improved storage symptoms in the long term after each surgery. Copyright © 2018 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.

Preclinical investigations of articular cartilage ablation with femtosecond and pulsed infrared lasers as an alternative to microfracture surgery

PubMed Central

Su, Erica; Sun, Hui; Juhasz, Tibor; Wong, Brian J. F.

2014-01-01

Abstract. Microfracture surgery is a bone marrow stimulation technique for treating cartilage defects and injuries in the knee. Current methods rely on surgical skill and instrumentation. This study investigates the potential use of laser technology as an alternate means to create the microfracture holes. Lasers investigated in this study include an erbium:YAG laser (λ=2.94  μm), titanium:sapphire femtosecond laser system (λ=1700  nm), and Nd:glass femtosecond laser (λ=1053  nm). Bovine samples were ablated at fluences of 8 to 18  J/cm2 with the erbium:YAG laser, at a power of 300±15  mW with the titanium:sapphire femtosecond system, and at an energy of 3  μJ/pulse with the Nd:glass laser. Samples were digitally photographed and histological sections were taken for analysis. The erbium:YAG laser is capable of fast and efficient ablation; specimen treated with fluences of 12 and 18  J/cm2 experienced significant amounts of bone removal and minimal carbonization with saline hydration. The femtosecond laser systems successfully removed cartilage but not clinically significant amounts of bone. Precise tissue removal was possible but not to substantial depths due to limitations of the systems. With additional studies and development, the use of femtosecond laser systems to ablate bone may be achieved at clinically valuable ablation rates. PMID:25200394

System and method for laser assisted sample transfer to solution for chemical analysis

DOEpatents

Van Berkel, Gary J; Kertesz, Vilmos

2014-01-28

A system and method for laser desorption of an analyte from a specimen and capturing of the analyte in a suspended solvent to form a testing solution are described. The method can include providing a specimen supported by a desorption region of a specimen stage and desorbing an analyte from a target site of the specimen with a laser beam centered at a radiation wavelength (.lamda.). The desorption region is transparent to the radiation wavelength (.lamda.) and the sampling probe and a laser source emitting the laser beam are on opposite sides of a primary surface of the specimen stage. The system can also be arranged where the laser source and the sampling probe are on the same side of a primary surface of the specimen stage. The testing solution can then be analyzed using an analytical instrument or undergo further processing.

Possible role of laser phototherapy in laser immunotherapy

NASA Astrophysics Data System (ADS)

Hode, Tomas; Hode, Lars

2009-02-01

Laser immunotherapy is a promising cancer treatment method that induces antitumor immunity and appears to be effective both locally and systemically. In this context, an important factor is the overall state of the immune system, both locally and systemically. The success of any immunotherapy treatment depends on the balance between the local immunosuppressive forces induced by the tumor and the immune response of the host organism. Factors that influence this balance include heat-shock proteins (for example HSP70), transforming growth factor β (TGF-β), tumor necrosis factor α (TNF-α), interleukins, and more. Laser phototherapy, which is based on non-thermal photobiological processes, has been shown to modulate the body's own immune response, both locally and systemically, with a strong influence on for example cytokine production and heat-shock protein synthesis. Laser phototherapy may therefore be an important component in the overall efficacy of laser immunotherapy, and may tip the balance between the immunosuppressive and immunostimulatory forces in favor of immunostimulation.

New energy conversion techniques in space, applicable to propulsion

NASA Technical Reports Server (NTRS)

Hertzberg, A.; Sun, K. C.

1989-01-01

The powering of aircraft with laser energy from a solar power satellite may be a promising new approach to the critical problem of the rising cost of fuel for aircraft transportation systems. The result is a nearly fuelless, pollution-free flight transportation system which is cost-competitive with the fuel-conservative airplane of the future. The major components of this flight system include a laser power satellite, relay satellites, laser-powered turbofans and a conventional airframe. The relay satellites are orbiting optical systems which intercept the beam from a power satellite and refocus and redirect the beam to its next target.

Optical system for UV-laser technological equipment

NASA Astrophysics Data System (ADS)

Fedosov, Yuri V.; Romanova, Galina E.; Afanasev, Maxim Ya.

2017-09-01

Recently there has been an intensive development of intelligent industrial equipment that is highly automated and can be rapidly adjusted for certain details. This equipment can be robotics systems, automatic wrappers and markers, CNC machines and 3D printers. The work equipment considered is the system for selective curing of photopolymers using a UV-laser and UV-radiation in such equipment that leads to additional technical difficulties. In many cases for transporting the radiation from the laser to the point processed, a multi-mirror system is used: however, such systems are usually difficult to adjust. Additionally, such multi-mirror systems are usually used as a part of the equipment for laser cutting of metals using high-power IR-lasers. For the UV-lasers, using many mirrors leads to crucial radiation losses because of many reflections. Therefore, during the development of the optical system for technological equipment using UV-laser we need to solve two main problems: to transfer the radiation for the working point with minimum losses and to include the system for controlling/handling the radiation spot position. We introduce a system for working with UV-lasers with 450mW of power and a wavelength of 0.45 μm based on a fiber system. In our modelling and design, we achieve spot sizes of about 300 μm, and the designed optical and mechanical systems (prototypes) were manufactured and assembled. In this paper, we present the layout of the technological unit, the results of the theoretical modelling of some parts of the system and some experimental results.

Ultra-stable clock laser system development towards space applications.

PubMed

Świerad, Dariusz; Häfner, Sebastian; Vogt, Stefan; Venon, Bertrand; Holleville, David; Bize, Sébastien; Kulosa, André; Bode, Sebastian; Singh, Yeshpal; Bongs, Kai; Rasel, Ernst Maria; Lodewyck, Jérôme; Le Targat, Rodolphe; Lisdat, Christian; Sterr, Uwe

2016-09-26

The increasing performance of optical lattice clocks has made them attractive for scientific applications in space and thus has pushed the development of their components including the interrogation lasers of the clock transitions towards being suitable for space, which amongst others requires making them more power efficient, radiation hardened, smaller, lighter as well as more mechanically stable. Here we present the development towards a space-compatible interrogation laser system for a strontium lattice clock constructed within the Space Optical Clock (SOC2) project where we have concentrated on mechanical rigidity and size. The laser reaches a fractional frequency instability of 7.9 × 10 -16 at 300 ms averaging time. The laser system uses a single extended cavity diode laser that gives enough power for interrogating the atoms, frequency comparison by a frequency comb and diagnostics. It includes fibre link stabilisation to the atomic package and to the comb. The optics module containing the laser has dimensions 60 × 45 × 8 cm 3 ; and the ultra-stable reference cavity used for frequency stabilisation with its vacuum system takes 30 × 30 × 30 cm 3 . The acceleration sensitivities in three orthogonal directions of the cavity are 3.6 × 10 -10 /g, 5.8 × 10 -10 /g and 3.1 × 10 -10 /g, where g ≈ 9.8 m/s 2 is the standard gravitational acceleration.

A Modular Control Platform for a Diode Pumped Alkali Laser

NASA Astrophysics Data System (ADS)

Shapiro, J.; Teare, S.

Many of the difficulties of creating compact, high power laser systems can be overcome if the heat dissipating properties of chemical lasers can be combined with the efficiency of diode lasers. Recently, the novel idea of using solid state diode lasers to pump gaseous gain media, such as is done in diode pumped alkali lasers (DPALs), has been proposed and early experiments have shown promising results. However, a number of technical issues need to be overcome to realize high output power from these lasers. In order to achieve higher power, the efficiency of coupling between pump laser energy and the chemical cell must be increased, and eventually multiple high power diode pumps must be combined and synchronized so that their energy can pump the chemical cell. Additionally, an inter-cavity adaptive optics system may be a requirement to be able to propagate these lasers with high efficiency. DPAL systems are complex and require a significant amount of data fusion and active feedback to control and optimize their performance. There are a wide range of components including pump lasers, gain cells and monitoring points needed to study and refine the overall laser system. In support of this dynamic development environment, we have developed a hardware framework using commercial off the shelf (COTS) components which supports the rapid assembly of functional system blocks into a cohesive integrated system. Critical to this system are a simple communication protocol, industry standard communication pipes (USB, Bluetooth, etc), and flexible high level scripting. Simplifying the integration process has the benefit of allowing flexible "on the fly" modifications to adapt the system as needed and enhance available functionality. The modular nature of the architecture allows scalability and adaptability as more pieces are added to the system. Key components of this system are demonstrated for selected portions of a DPAL system using a USB backbone.

TOPSAT: Global space topographic mission

NASA Technical Reports Server (NTRS)

Vetrella, Sergio

1993-01-01

Viewgraphs on TOPSAT Global Space Topographic Mission are presented. Topics covered include: polar region applications; terrestrial ecosystem applications; stereo electro-optical sensors; space-based stereoscopic missions; optical stereo approach; radar interferometry; along track interferometry; TOPSAT-VISTA system approach; ISARA system approach; topographic mapping laser altimeter; and role of multi-beam laser altimeter.

Navigated Pattern Laser System versus Single-Spot Laser System for Postoperative 360-Degree Laser Retinopexy.

PubMed

Kulikov, Alexei N; Maltsev, Dmitrii S; Boiko, Ernest V

2016-01-01

Purpose . To compare three 360°-laser retinopexy (LRP) approaches (using navigated pattern laser system, single-spot slit-lamp (SL) laser delivery, and single-spot indirect ophthalmoscope (IO) laser delivery) in regard to procedure duration, procedural pain score, technical difficulties, and the ability to achieve surgical goals. Material and Methods . Eighty-six rhegmatogenous retinal detachment patients (86 eyes) were included in this prospective randomized study. The mean procedural time, procedural pain score (using 4-point Verbal Rating Scale), number of laser burns, and achievement of the surgical goals were compared between three groups (pattern LRP (Navilas® laser system), 36 patients; SL-LRP, 28 patients; and IO-LRP, 22 patients). Results . In the pattern LRP group, the amount of time needed for LRP and pain level were statistically significantly lower, whereas the number of applied laser burns was higher compared to those in the SL-LRP group and in the IO-LRP group. In the pattern LRP, SL-LRP, and IO-LRP groups, surgical goals were fully achieved in 28 (77.8%), 17 (60.7%), and 13 patients (59.1%), respectively ( p > 0.05). Conclusion . The navigated pattern approach allows improving the treatment time and pain in postoperative 360° LRP. Moreover, 360° pattern LRP is at least as effective in achieving the surgical goal as the conventional (slit-lamp or indirect ophthalmoscope) approaches with a single-spot laser.

Adaptive optics program update at TMT

NASA Astrophysics Data System (ADS)

Boyer, C.; Ellerbroek, B.

2016-07-01

The TMT first light AO facility consists of the Narrow Field Infra-Red AO System (NFIRAOS), the associated Laser Guide Star Facility (LGSF) and the AO Executive Software (AOESW). Design, fabrication and prototyping activities of the TMT first light AO systems and their components have significantly ramped up in Canada, China, France, and in the US. NFIRAOS is an order 60 x 60 laser guide star (LGS) multi-conjugate AO (MCAO) system, which provides uniform, diffraction-limited performance in the J, H, and K bands over 34 x 34 arc sec fields with 50 per cent sky coverage at the galactic pole, as required to support the TMT science cases. NFIRAOS includes two deformable mirrors, six laser guide star wavefront sensors, one high order Pyramid WFS for natural guide star AO, and up to three low-order, IR, natural guide star on-instrument wavefront sensors (OIWFS) and four on-detector guide windows (ODGW) within each client instrument. The first light LGSF system includes six sodium lasers to generate the NFIRAOS laser guide stars. In this paper, we will provide an update on the progress in designing, prototyping, fabricating and modeling the TMT first light AO systems and their AO components over the last two years. TMT is continuing with detailed AO modeling to support the design and development of the first light AO systems and components. Major modeling topics studied during the last two years include further studies in the area of pyramid wavefront sensing, high precision astrometry, PSF reconstruction for LGS MCAO, LGSF wavefront error budget and sophisticated low order mode temporal filtering.

Control system of an excitation power supply for fast axial flow CO2 lasersupda

NASA Astrophysics Data System (ADS)

Li, Bo; Jia, Xinting; Yuan, Hao; Gao, Yuhu; Wang, Youqing

2009-08-01

A switching power control system of fast axial flow CO2 lasers based on DSP is presented. The key techniques are described in detail, include the control principle, realization method and program design. The experiment showed that the system make the laser discharge stably and work in multi-mode. The discharge current can be adjusted from 3mA to 85mA continuously. 20-2000Hz frequency, 0-100% duty cycle laser pulse is achieved. The power supply can improve the processing efficiency and quality.

Ultrastable laser array at 633 nm for real-time dimensional metrology

NASA Astrophysics Data System (ADS)

Lawall, John; Pedulla, J. Marc; Le Coq, Yann

2001-07-01

We describe a laser system for very-high-accuracy dimensional metrology. A sealed-cavity helium-neon laser is offset locked to an iodine-stabilized laser in order to realize a secondary standard with higher power and less phase noise. Synchronous averaging is employed to remove the effect of the frequency modulation present on the iodine-stabilized laser. Additional lasers are offset locked to the secondary standard for use in interferometry. All servo loops are implemented digitally. The offset-locked lasers have intrinsic linewidths of the order of 2.5 kHz and exhibit a rms deviation from the iodine-stabilized laser below 18 kHz. The amplitude noise is at the shot-noise limit for frequencies above 700 kHz. We describe and evaluate the system in detail, and include a discussion of the noise associated with various types of power supplies.

Method and apparatus for controlling carrier envelope phase

DOEpatents

Chang, Zenghu [Manhattan, KS; Li, Chengquan [Sunnyvale, CA; Moon, Eric [Manhattan, KS

2011-12-06

A chirped pulse amplification laser system. The system generally comprises a laser source, a pulse modification apparatus including first and second pulse modification elements separated by a separation distance, a positioning element, a measurement device, and a feedback controller. The laser source is operable to generate a laser pulse and the pulse modification apparatus operable to modify at least a portion of the laser pulse. The positioning element is operable to reposition at least a portion of the pulse modification apparatus to vary the separation distance. The measurement device is operable to measure the carrier envelope phase of the generated laser pulse and the feedback controller is operable to control the positioning element based on the measured carrier envelope phase to vary the separation distance of the pulse modification elements and control the carrier envelope phase of laser pulses generated by the laser source.

Constructing a Laser Stabilization System for a Parity Non-Conservation Experiment with Francium

NASA Astrophysics Data System (ADS)

Dehart, A. C.; Gwinner, Gerald; Kossin, Michael; Behr, John; Gorelov, Alexandre; Kalita, Mukut; Pearson, Matthew; Aubin, Seth; Gomez Garcia, Eduardo; Orozco, Luis

2017-04-01

We are developing an experiment at TRIUMF to test the Standard model at low energies by measuring Parity Non-Conservation (PNC) effects in francium. Current efforts include preparations to study the 7s - 8s electric dipole (E1) forbidden transition in francium at 507 nm under the influence of an electric field. Fr has no stable isotope; therefore to frequency-stabilize our laser at 507 nm, we are developing a laser stabilization system by using the Pound-Drever-Hall technique with a Fabry-Perot cavity made of Ultra Low Expansion Glass (ULE) as our stable frequency reference. The system will stabilize a 1014 nm laser, which will be frequency doubled to 507 nm, before sending the light to our cold and trapped francium sample. We will report on our recent experiences with the laser stabilization system. Supported by NSERC, NRC/TRIUMF, DOE, NSF, CONACYT, Fulbright, and U. of Manitoba.

The airborne laser ranging system, its capabilities and applications

NASA Technical Reports Server (NTRS)

Kahn, W. D.; Degnan, J. J.; Englar, T. S., Jr.

1982-01-01

The airborne laser ranging system is a multibeam short pulse laser ranging system on board an aircraft. It simultaneously measures the distances between the aircraft and six laser retroreflectors (targets) deployed on the Earth's surface. The system can interrogate over 100 targets distributed over an area of 25,000 sq, kilometers in a matter of hours. Potentially, a total of 1.3 million individual range measurements can be made in a six hour flight. The precision of these range measurements is approximately + or - 1 cm. These measurements are used in procedure which is basically an extension of trilateration techniques to derive the intersite vector between the laser ground targets. By repeating the estimation of the intersite vector, strain and strain rate errors can be estimated. These quantities are essential for crustal dynamic studies which include determination and monitoring of regional strain in the vicinity of active fault zones, land subsidence, and edifice building preceding volcanic eruptions.

Vibration-tolerant narrow-linewidth semiconductor disk laser using novel frequency-stabilisation schemes

NASA Astrophysics Data System (ADS)

Hunter, Craig R.; Jones, Brynmor E.; Schlosser, Peter; Sørensen, Simon Toft; Strain, Michael J.; McKnight, Loyd J.

2018-02-01

This paper will present developments in narrow-linewidth semiconductor-disk-laser systems using novel frequencystabilisation schemes for reduced sensitivity to mechanical vibrations, a critical requirement for mobile applications. Narrow-linewidth single-frequency lasers are required for a range of applications including metrology and highresolution spectroscopy. Stabilisation of the laser was achieved using a monolithic fibre-optic ring resonator with free spectral range of 181 MHz and finesse of 52 to act as passive reference cavity for the laser. Such a cavity can operate over a broad wavelength range and is immune to a wide band of vibrational frequency noise due to its monolithic implementation. The frequency noise of the locked system has been measured and compared to typical Fabry-Perotlocked lasers using vibration equipment to simulate harsh environments, and analysed here. Locked linewidths of < 40 kHz have been achieved. These developments offer a portable, narrow-linewidth laser system for harsh environments that can be flexibly designed for a range of applications.

LASER Tech Briefs, Fall 1994. Volume 2, No. 4

NASA Technical Reports Server (NTRS)

1994-01-01

Topics in this issue of LASER Tech briefs include: Electronic Components and Circuits. Electronic Systems, Physical Sciences, Materials, Computer Programs, Fabrication Technology, Mathematics and Information Sciences, and Life Sciences

Development of Shanghai satellite laser ranging station

NASA Technical Reports Server (NTRS)

Yang, Fu-Min; Tan, De-Tong; Xiao, Chi-Kun; Chen, Wan-Zhen; Zhang, J.-H.; Zhang, Z.-P.; Lu, Wen-Hu; Hu, Z.-Q.; Tang, W.-F.; Chen, J.-P.

1993-01-01

The topics covered include the following: improvement of the system hardware; upgrading of the software; the observation status; preliminary daylight tracking capability; testing the new type of laser; and future plans.

System Model for MEMS based Laser Ultrasonic Receiver

NASA Technical Reports Server (NTRS)

Wilson, William C.

2002-01-01

A need has been identified for more advanced nondestructive Evaluation technologies for assuring the integrity of airframe structures, wiring, etc. Laser ultrasonic inspection instruments have been shown to detect flaws in structures. However, these instruments are generally too bulky to be used in the confined spaces that are typical of aerospace vehicles. Microsystems technology is one key to reducing the size of current instruments and enabling increased inspection coverage in areas that were previously inaccessible due to instrument size and weight. This paper investigates the system modeling of a Micro OptoElectroMechanical System (MOEMS) based laser ultrasonic receiver. The system model is constructed in software using MATLAB s dynamical simulator, Simulink. The optical components are modeled using geometrical matrix methods and include some image processing. The system model includes a test bench which simulates input stimuli and models the behavior of the material under test.

Laser-initiated ordnance for air-to-air missiles

NASA Technical Reports Server (NTRS)

Sumpter, David R.

1993-01-01

McDonnell Douglas Missile Systems Company (MDMSC) has developed a laser ignition subsystem (LIS) for air-to-air missile applications. The MDMSC subsystem is designed to activate batteries, unlock fins, and sequence propulsion system events. The subsystem includes Pyro Zirconium Pump (PZP) lasers, mechanical Safe & Arm, fiber-optic distribution system, and optically activated pyrotechnic devices (initiators, detonators, and thermal batteries). The LIS design has incorporated testability features for the laser modules, drive electronics, fiber-optics, and pyrotechnics. Several of the LIS have been fabricated and have supported thermal battery testing, integral rocket ramjet testing, and have been integrated into integral rocket ramjet flight test vehicles as part of the flight control subsystem.

Aerosol mass spectrometry systems and methods

DOEpatents

Fergenson, David P.; Gard, Eric E.

2013-08-20

A system according to one embodiment includes a particle accelerator that directs a succession of polydisperse aerosol particles along a predetermined particle path; multiple tracking lasers for generating beams of light across the particle path; an optical detector positioned adjacent the particle path for detecting impingement of the beams of light on individual particles; a desorption laser for generating a beam of desorbing light across the particle path about coaxial with a beam of light produced by one of the tracking lasers; and a controller, responsive to detection of a signal produced by the optical detector, that controls the desorption laser to generate the beam of desorbing light. Additional systems and methods are also disclosed.

Laser Ignition Technology for Bi-Propellant Rocket Engine Applications

NASA Technical Reports Server (NTRS)

Thomas, Matt; Bossard, John; Early, Jim; Trinh, Huu; Dennis, Jay; Turner, James (Technical Monitor)

2001-01-01

This viewgraph presentation gives an overview of laser ignition technology for bipropellant rocket engines applications. The objectives of this project include: (1) the selection test chambers and flows; (2) definition of the laser ignition setup; (3) pulse format optimization; (4) fiber optic coupled laser ignition system analysis; and (5) chamber integration issues definition. The testing concludes that rocket combustion chamber laser ignition is imminent. Support technologies (multiplexing, window durability/cleaning, and fiber optic durability) are feasible.

Proceedings of the Fourth Laser Hydrography Symposium at Defence Research Centre and Royal Australian Navy Hydrographic Office

NASA Astrophysics Data System (ADS)

Penny, M. F.; Phillips, D. M.

1981-03-01

At this Symposium, research on laser hydrography and related development programs currently in progress in the United States of America, Canada, and Australia, were reported. The depth sounding systems described include the US Airborne Oceanographic Lidar and Hydrographic Airborne Laser Sounder, the Canadian Profiling Lidar Bathymeter, and the Australian Laser Airborne Depth Sounder. Other papers presented research on blue-green lasers, theoretical modelling, position fixing, and data processing.

Ground-to-orbit laser propulsion: Advanced applications

NASA Technical Reports Server (NTRS)

Kare, Jordin T.

1990-01-01

Laser propulsion uses a large fixed laser to supply energy to heat an inert propellant in a rocket thruster. Such a system has two potential advantages: extreme simplicity of the thruster, and potentially high performance, particularly high exhaust velocity. By taking advantage of the simplicity of the thruster, it should be possible to launch small (10 to 1000 kg) payloads to orbit using roughly 1 MW of average laser power per kg of payload. The incremental cost of such launches would be of an order of $200/kg for the smallest systems, decreasing to essentially the cost of electricity to run the laser (a few times $10/kg) for larger systems. Although the individual payload size would be smaller, a laser launch system would be inherently high-volume, with the capacity to launch tens of thousands of payloads per year. Also, with high exhaust velocity, a laser launch system could launch payloads to high velocities - geosynchronous transfer, Earth escape, or beyond - at a relatively small premium over launches to LEO. The status of pulsed laser propulsion is briefly reviewed including proposals for advanced vehicles. Several applications appropriate to the early part of the next century and perhaps valuable well into the next millennium are discussed qualitatively: space habitat supply, deep space mission supply, nuclear waste disposal, and manned vehicle launching.

Single steady frequency and narrow-linewidth external-cavity semiconductor laser

NASA Astrophysics Data System (ADS)

Zhao, Weirui; Jiang, Pengfei; Xie, Fuzeng

2003-11-01

A single longitudinal mode and narrow line width external cavity semiconductor laser is proposed. It is constructed with a semiconductor laser, collimator, a flame grating, and current and temperature control systems. The one facet of semiconductor laser is covered by high transmission film, and another is covered by high reflection film. The flame grating is used as light feedback element to select the mode of the semiconductor laser. The temperature of the constructed external cavity semiconductor laser is stabilized in order of 10-3°C by temperature control system. The experiments have been carried out and the results obtained - the spectral line width of this laser is compressed to be less than 1.4MHz from its original line-width of more than 1200GHz and the output stability (including power and mode) is remarkably enhanced.

Nd:YAG development for spaceborne laser ranging system

NASA Technical Reports Server (NTRS)

Harper, L. L.; Logan, K. E.; Williams, R. H.; Stevens, D. A.

1979-01-01

The results of the development of a unique modelocked laser device to be utilized in future NASA space-based, ultraprecision laser ranger systems are summarized. The engineering breadboard constructed proved the feasibility of the pump-pulsed, actively modelocked, PTM Q-switched Nd:YAG laser concept for the generation of subnanosecond pulses suitable for ultra-precision ranging. The laser breadboard also included a double-pass Nd:YAG amplifier and provision for a Type II KD*P frequency doubler. The specific technical accomplishment was the generation of single 150 psec, 20-mJ pulses at 10 pps at a wavelength of 1.064 micrometers with 25 dB suppression of pre-and post-pulses.

Laser angle sensor

NASA Technical Reports Server (NTRS)

Pond, C. R.; Texeira, P. D.

1985-01-01

A laser angle measurement system was designed and fabricated for NASA Langley Research Center. The instrument is a fringe counting interferometer that monitors the pitch attitude of a model in a wind tunnel. A laser source and detector are mounted above the model. Interference fringes are generated by a small passive element on the model. The fringe count is accumulated and displayed by a processor in the wind tunnel control room. This report includes optical and electrical schematics, system maintenance and operation procedures.

Laser Transmitter Aims At Laser Beacon

NASA Technical Reports Server (NTRS)

Hemmati, Hamid; Lesh, James R.

1993-01-01

Transmitter part of developmental optical communication system. Compact, lightweight, partially-self-aiming laser transmitter built to verify some capabilities of developmental free-space optical communication system. Design capable of providing 0.5 Mbps data return over range equal to Moon-Earth distance. Breadboard of transmitting terminal constructed and tested in laboratory. Prototype transmitter includes receiving circuitry that keeps it aimed at beacon, once brought into initial alignment within about 1.7 degrees of line of sight to beacon.

Ring-laser gyroscope system using dispersive element(s)

NASA Technical Reports Server (NTRS)

Smith, David D. (Inventor)

2010-01-01

A ring-laser gyroscope system includes a ring-laser gyroscope (RLG) and at least one dispersive element optically coupled to the RLG's ring-shaped optical path. Each dispersive element has a resonant frequency that is approximately equal to the RLG's lasing frequency. A group index of refraction defined collectively by the dispersive element(s) has (i) a real portion that is greater than zero and less than one, and (ii) an imaginary portion that is less than zero.

High Average Power Laser Gain Medium With Low Optical Distortion Using A Transverse Flowing Liquid Host

DOEpatents

Comaskey, Brian J.; Ault, Earl R.; Kuklo, Thomas C.

2005-07-05

A high average power, low optical distortion laser gain media is based on a flowing liquid media. A diode laser pumping device with tailored irradiance excites the laser active atom, ion or molecule within the liquid media. A laser active component of the liquid media exhibits energy storage times longer than or comparable to the thermal optical response time of the liquid. A circulation system that provides a closed loop for mixing and circulating the lasing liquid into and out of the optical cavity includes a pump, a diffuser, and a heat exchanger. A liquid flow gain cell includes flow straighteners and flow channel compression.

Airborne laser systems for atmospheric sounding in the near infrared

NASA Astrophysics Data System (ADS)

Sabatini, Roberto; Richardson, Mark A.; Jia, Huamin; Zammit-Mangion, David

2012-06-01

This paper presents new techniques for atmospheric sounding using Near Infrared (NIR) laser sources, direct detection electro-optics and passive infrared imaging systems. These techniques allow a direct determination of atmospheric extinction and, through the adoption of suitable inversion algorithms, the indirect measurement of some important natural and man-made atmospheric constituents, including Carbon Dioxide (CO2). The proposed techniques are suitable for remote sensing missions performed by using aircraft, satellites, Unmanned Aerial Vehicles (UAV), parachute/gliding vehicles, Roving Surface Vehicles (RSV), or Permanent Surface Installations (PSI). The various techniques proposed offer relative advantages in different scenarios. All are based on measurements of the laser energy/power incident on target surfaces of known geometric and reflective characteristics, by means of infrared detectors and/or infrared cameras calibrated for radiance. Experimental results are presented relative to ground and flight trials performed with laser systems operating in the near infrared (NIR) at λ = 1064 nm and λ = 1550 nm. This includes ground tests performed with 10 Hz and 20 KHz PRF NIR laser systems in a variety of atmospheric conditions, and flight trials performed with a 10 Hz airborne NIR laser system installed on a TORNADO aircraft, flying up to altitudes of 22,000 ft above ground level. Future activities are planned to validate the atmospheric retrieval algorithms developed for CO2 column density measurements, with emphasis on aircraft related emissions at airports and other high air-traffic density environments.

Method and system for compact efficient laser architecture

DOEpatents

Bayramian, Andrew James; Erlandson, Alvin Charles; Manes, Kenneth Rene; Spaeth, Mary Louis; Caird, John Allyn; Deri, Robert J.

2015-09-15

A laser amplifier module having an enclosure includes an input window, a mirror optically coupled to the input window and disposed in a first plane, and a first amplifier head disposed along an optical amplification path adjacent a first end of the enclosure. The laser amplifier module also includes a second amplifier head disposed along the optical amplification path adjacent a second end of the enclosure and a cavity mirror disposed along the optical amplification path.

Laser focus compensating sensing and imaging device

DOEpatents

Vann, Charles S.

1993-01-01

A laser focus compensating sensing and imaging device permits the focus of a single focal point of different frequency laser beams emanating from the same source point. In particular it allows the focusing of laser beam originating from the same laser device but having differing intensities so that a low intensity beam will not convert to a higher frequency when passing through a conversion crystal associated with the laser generating device. The laser focus compensating sensing and imaging device uses a cassegrain system to fold the lower frequency, low intensity beam back upon itself so that it will focus at the same focal point as a high intensity beam. An angular tilt compensating lens is mounted about the secondary mirror of the cassegrain system to assist in alignment. In addition cameras or CCD's are mounted with the primary mirror to sense the focused image. A convex lens is positioned co-axial with the cassegrain system on the side of the primary mirror distal of the secondary for use in aligning a target with the laser beam. A first alternate embodiment includes a cassegrain system using a series of shutters and an internally mounted dichroic mirror. A second alternate embodiment uses two laser focus compensating sensing and imaging devices for aligning a moving tool with a work piece.

Laser focus compensating sensing and imaging device

DOEpatents

Vann, C.S.

1993-08-31

A laser focus compensating sensing and imaging device permits the focus of a single focal point of different frequency laser beams emanating from the same source point. In particular it allows the focusing of laser beam originating from the same laser device but having differing intensities so that a low intensity beam will not convert to a higher frequency when passing through a conversion crystal associated with the laser generating device. The laser focus compensating sensing and imaging device uses a Cassegrain system to fold the lower frequency, low intensity beam back upon itself so that it will focus at the same focal point as a high intensity beam. An angular tilt compensating lens is mounted about the secondary mirror of the Cassegrain system to assist in alignment. In addition cameras or CCD's are mounted with the primary mirror to sense the focused image. A convex lens is positioned co-axial with the Cassegrain system on the side of the primary mirror distal of the secondary for use in aligning a target with the laser beam. A first alternate embodiment includes a Cassegrain system using a series of shutters and an internally mounted dichroic mirror. A second alternate embodiment uses two laser focus compensating sensing and imaging devices for aligning a moving tool with a work piece.

Packaging of fiber lasers and components for use in harsh environments

NASA Astrophysics Data System (ADS)

Creeden, Daniel; Johnson, Benjamin R.; Jones, Casey; Ibach, Charles; Lemons, Michael; Budni, Peter A.; Zona, James P.; Marcinuk, Adam; Willis, Chris; Sweeney, James; Setzler, Scott D.

2016-03-01

High power continuous and pulsed fiber lasers and amplifiers have become more prevalent in laser systems over the last ten years. In fielding such systems, strong environmental and operational factors drive the packaging of the components. These include large operational temperature ranges, non-standard wavelengths of operation, strong vibration, and lack of water cooling. Typical commercial fiber components are not designed to survive these types of environments. Based on these constraints, we have had to develop and test a wide range of customized fiber-based components and systems to survive in these conditions. In this paper, we discuss some of those designs and detail the testing performed on those systems and components. This includes the use of commercial off-the-shelf (COTS) components, modified to survive extended temperature ranges, as well as customized components designed specifically for performance in harsh environments. Some of these custom components include: ruggedized/monolithic fiber spools; detachable and repeatable fiber collimators; low loss fiber-to-fiber coupling schemes; and high power fiber-coupled isolators.

A USPL functional system with articulated mirror arm for in-vivo applications in dentistry

NASA Astrophysics Data System (ADS)

Schelle, Florian; Meister, Jörg; Dehn, Claudia; Oehme, Bernd; Bourauel, Christoph; Frentzen, Mathias

Ultra-short pulsed laser (USPL) systems for dental application have overcome many of their initial disadvantages. However, a problem that has not yet been addressed and solved is the beam delivery into the oral cavity. The functional system that is introduced in this study includes an articulated mirror arm, a scanning system as well as a handpiece, allowing for freehand preparations with ultra-short laser pulses. As laser source an Nd:YVO4 laser is employed, emitting pulses with a duration of tp < 10 ps at a repetition rate of up to 500 kHz. The centre wavelength is at 1064 nm and the average output power can be tuned up to 9 W. The delivery system consists of an articulated mirror arm, to which a scanning system and a custom made handpiece are connected, including a 75 mm focussing lens. The whole functional system is compact in size and moveable. General characteristics like optical losses and ablation rate are determined and compared to results employing a fixed setup on an optical table. Furthermore classical treatment procedures like cavity preparation are being demonstrated on mammoth ivory. This study indicates that freehand preparation employing an USPL system is possible but challenging, and accompanied by a variety of side-effects. The ablation rate with fixed handpiece is about 10 mm3/min. Factors like defocussing and blinding affect treatment efficiency. Laser sources with higher average output powers might be needed in order to reach sufficient preparation speeds.

High-energy laser activities at MBDA Germany

NASA Astrophysics Data System (ADS)

Mohring, Bernd; Dietrich, Stephan; Tassini, Leonardo; Protz, Rudolf; Geidek, Franz; Zoz, Jürgen

2013-05-01

At MBDA Germany a concept for a high-energy laser weapon system is investigated, which is based on existing industrial laser sources. Due to the enormous progress in the field of high-power fiber lasers, commercial industrial fiber lasers are now available delivering a nearly-diffraction limited beam quality with power levels of up to 10 kW. By using a geometric beam coupling scheme, a number of individual high-power fiber laser beams are combined together using one common beam director telescope. A total laser beam power of more than 100 kW can be achieved, which is sufficient for an operational laser weapon system. The individual beams from the different lasers are steered by servo-loops using fast tip-tilt mirrors. This principle enables the concentration of the total laser beam power at one common focal point on a distant target, also allowing fine tracking of target movements and first-order compensation of turbulence effects on laser beam propagation. The proposed beam combination concept was demonstrated by using different experimental set-ups. A number of experiments were performed successfully to investigate laser beam target interaction and target fine tracking, also at large distances and at moving targets. Content and results of these investigations are reported, which demonstrate the complete engagement sequence for a C-RAM scenario. This includes subsequent steps of target acquisition by radar and IR optics, followed by large angle coarse tracking, active fine tracking and destruction of the target by the laser system. This successful implementation of geometric beam combining is an important step for the realization of a laser weapon system in the near future.

Study of application and key technology of the high-energy laser weapon in optoelectronic countermeasure

NASA Astrophysics Data System (ADS)

Qu, Zhou; Xing, Hao; Wang, Dawei; Wang, Qiugui

2015-10-01

High-energy Laser weapon is a new-style which is developing rapidly nowadays. It is a one kind of direction energy weapon which can destroy the targets or make them invalid. High-energy Laser weapon has many merits such as concentrated energy, fast transmission, long operating range, satisfied precision, fast shift fire, anti-electromagnetic interference, reusability, cost-effectiveness. High-energy Laser weapon has huge potential for modern warfare since its laser beam launch attack to the target by the speed of light. High-energy Laser weapon can be deployed by multiple methods such as skyborne, carrier borne, vehicle-mounted, foundation, space platform. Besides the connection with command and control system, High-energy Laser weapon is consist of high-energy laser and beam steering. Beam steering is comprised of Large diameter launch system and Precision targeting systems. Meanwhile, beam steering includes the distance measurement of target location, detection system of television and infrared sensor, adaptive optical system of Laser atmospheric distortion correction. The development of laser technology is very fast in recent years. A variety of laser sources have been regarded as the key component in many optoelectronic devices. For directed energy weapon, the progress of laser technology has greatly improved the tactical effectiveness, such as increasing the range and strike precision. At the same time, the modern solid-state laser has become the ideal optical source for optical countermeasure, because it has high photoelectric conversion efficiency and small volume or weight. However, the total performance is limited by the mutual cooperation between different subsystems. The optical countermeasure is a complex technique after many years development. The key factor to evaluate the laser weapon can be formulated as laser energy density to target. This article elaborated the laser device technology of optoelectronic countermeasure and Photoelectric tracking technology. Also the allocation of optoelectronic countermeasure was discussed in this article. At last, this article prospected the future development of high-energy laser.

Spectrally Tailored Pulsed Thulium Fiber Laser System for Broadband Lidar CO2 Sensing

NASA Technical Reports Server (NTRS)

Heaps, William S.; Georgieva, Elena M.; McComb, Timothy S.; Cheung, Eric C.; Hassell, Frank R.; Baldauf, Brian K.

2011-01-01

Thulium doped pulsed fiber lasers are capable of meeting the spectral, temporal, efficiency, size and weight demands of defense and civil applications for pulsed lasers in the eye-safe spectral regime due to inherent mechanical stability, compact "all-fiber" master oscillator power amplifier (MOPA) architectures, high beam quality and efficiency. Thulium fiber's longer operating wavelength allows use of larger fiber cores without compromising beam quality, increasing potential single aperture pulse energies. Applications of these lasers include eye-safe laser ranging, frequency conversion to longer or shorter wavelengths for IR countermeasures and sensing applications with otherwise tough to achieve wavelengths and detection of atmospheric species including CO2 and water vapor. Performance of a portable thulium fiber laser system developed for CO2 sensing via a broadband lidar technique with an etalon based sensor will be discussed. The fielded laser operates with approximately 280 J pulse energy in 90-150ns pulses over a tunable 110nm spectral range and has a uniquely tailored broadband spectral output allowing the sensing of multiple CO2 lines simultaneously, simplifying future potentially space based CO2 sensing instruments by reducing the number and complexity of lasers required to carry out high precision sensing missions. Power scaling and future "all fiber" system configurations for a number of ranging, sensing, countermeasures and other yet to be defined applications by use of flexible spectral and temporal performance master oscillators will be discussed. The compact, low mass, robust, efficient and readily power scalable nature of "all-fiber" thulium lasers makes them ideal candidates for use in future space based sensing applications.

Lasers in Apicoectomy: A Brief Review.

PubMed

Mohammadi, Zahed; Jafarzadeh, Hamid; Shalavi, Sousan; Kinoshita, Jun-Ichiro; Giardino, Luciano

2017-02-01

Since the invention of laser, various applications for lasers in endodontics have been proposed, such as disinfection of the root canal system, canal shaping, pulp diagnosis, and apico-ectomy. One of the major applications of laser in endodontics is apicoectomy. The aim of this article is to review the benefits and drawbacks of laser applications in apicoectomy, including effect on apical seal, effect on dentin permeability, effect on postsurgery pain, effect on crack formation, effect on root-end morphology, effect on treatment outcome, and connective tissue response to laser-treated dentin.

Laser Radar Study Using Resonance Absorption for Remote Detection Of Air Pollutants

NASA Technical Reports Server (NTRS)

Igarashi, Takashi

1973-01-01

A laser radar using resonance absorption has an advantage of increased detection range and sensitivity compared with that achieved by Raman or resonance back scattering. In this paper, new laser radar system using resonance absorption is proposed and results obtained from this laser radar system are discussed. NO2, SO2 gas has an absorption spectrum at 4500 A and 3000 A respectively as shown in Fig. 1. A laser light including at least a set of an absorption peak (lambda)1 and a valley (lambda)2 is emitted into a pollutant atmosphere. The light reflected with a topographical reflector or an atmospheric Mie scattering as distributed reflectors is received and divided into two wavelength components (lambda)1 and (lambda)2. The laser radar system used in the investigation is shown in Fig', 2 and consists of a dye laser transmitter, an optical receiver with a special monochrometer and a digital processer. Table 1 shows the molecular constants of NO2, and SO2 and the dye laser used in this experiment. In this system, the absolute concentration of the pollutant gas can be measured in comparison with a standard gas cell. The concentration of NO2, SO2 as low as 0.1 ppm have been measured at 100 m depth resolution. For a 1 mJ laser output, the observable range of this system achieved up to 300 m using the distributed Mie reflector. The capability and technical limitation of the system will be discussed in detail.

Evaluation of Analysis Conditions for Laser-Pulsed Atom Probe Tomography: Example of Cemented Tungsten Carbide.

PubMed

Peng, Zirong; Choi, Pyuck-Pa; Gault, Baptiste; Raabe, Dierk

2017-04-01

Cemented tungsten carbide has been analyzed using laser-pulsed atom probe tomography (APT). The influence of experimental parameters, including laser pulse energy, pulse repetition rate, and specimen base temperature, on the acquired data were evaluated from different aspects, such as mass spectrum, chemical composition, noise-to-signal ratio, and multiple events. Within all the applied analysis conditions, only 1 MHz pulse repetition rate led to a strong detector saturation effect, resulting in a largely biased chemical composition. A comparative study of the laser energy settings showed that an ~12 times higher energy was required for the less focused green laser of the LEAPTM 3000X HR system to achieve a similar evaporation field as the finer spot ultraviolet laser of the LEAPTM 5000 XS system.

Excimer lasers

NASA Technical Reports Server (NTRS)

Palmer, A. J.; Hess, L. D.; Stephens, R. R.; Pepper, D. M.

1977-01-01

The results of a two-year investigation into the possibility of developing continuous wave excimer lasers are reported. The program included the evaluation and selection of candidate molecular systems and discharge pumping techniques. The K Ar/K2 excimer dimer molecules and the xenon fluoride excimer molecule were selected for study; each used a transverse and capillary discharges pumping technique. Experimental and theoretical studies of each of the two discharge techniques applied to each of the two molecular systems are reported. Discharge stability and fluorine consumption were found to be the principle impediments to extending the XeF excimer laser into the continuous wave regime. Potassium vapor handling problems were the principal difficulty in achieving laser action on the K Ar/K2 system. Of the four molecular systems and pumping techniques explored, the capillary discharge pumped K Ar/K2 system appears to be the most likely candidate for demonstrating continuous wave excimer laser action primarily because of its predicted lower pumping threshold and a demonstrated discharge stability advantage.

Shuttle Laser Altimeter

NASA Technical Reports Server (NTRS)

Bufton, Jack L.; Harding, David J.; Garvin, James B.

1999-01-01

The Shuttle Laser Altimeter (SLA) is a Hitchhiker experiment that has flown twice; first on STS-72 in January 1996 and then on STS-85 in August 1997. Both missions produced successful laser altimetry and surface lidar data products from approximately 80 hours per mission of SLA data operations. A total of four Shuttle missions are planned for the SLA series. This paper documents SLA mission results and explains SLA pathfinder accomplishments at the mid-point in this series of Hitchhiker missions. The overall objective of the SLA mission series is the transition of the Goddard Space Flight Center airborne laser altimeter and lidar technology to low Earth orbit as a pathfinder for NASA operational space-based laser remote sensing devices. Future laser altimeter sensors will utilize systems and approaches being tested with SLA, including the Multi-Beam Laser Altimeter (MBLA) and the Geoscience Laser Altimeter System (GLAS). MBLA is the land and vegetation laser sensor for the NASA Earth System Sciences Pathfinder Vegetation Canopy Lidar (VCL) Mission, and GLAS is the Earth Observing System facility instrument on the Ice, Cloud, and Land Elevation Satellite (ICESat). The Mars Orbiting Laser Altimeter, now well into a multi-year mapping mission at the red planet, is also directly benefiting from SLA data analysis methods, just as SLA benefited from MOLA spare parts and instrument technology experience [5] during SLA construction in the early 1990s.

Means and method for capillary zone electrophoresis with laser-induced indirect fluorescence detection

DOEpatents

Yeung, Edward S.; Kuhr, Werner G.

1996-02-20

A means and method for capillary zone electrphoresis with laser-induced indirect fluorescence detection. A detector is positioned on the capillary tube of a capillary zone electrophoresis system. The detector includes a laser which generates a laser beam which is imposed upon a small portion of the capillary tube. Fluorescence of the elutant electromigrating through the capillary tube is indirectly detected and recorded.

Means and method for capillary zone electrophoresis with laser-induced indirect fluorescence detection

DOEpatents

Yeung, Edwards; Kuhr, Werner G.

1991-04-09

A means and method for capillary zone electrphoresis with laser-induced indirect fluorescence detection. A detector is positioned on the capillary tube of a capillary zone electrophoresis system. The detector includes a laser which generates a laser beam which is imposed upon a small portion of the capillary tube. Fluorescence of the elutant electromigrating through the capillary tube is indirectly detected and recorded.

Perspective on One Decade of Laser Propulsion Research at Air Force Research Laboratory

DOE Office of Scientific and Technical Information (OSTI.GOV)

Larson, C. William

The Air Force Laser Propulsion Program spanned nearly 10-years and included about 35-weeks of experimental research with the Pulsed Laser Vulnerability Test System of the High Energy Laser Systems Test Facility at White Sands Missile Range, New Mexico, WSMR/HELSTF/PLVTS. PLVTS is a pulsed CO2 laser that produces up to 10 kW of power in {approx}10 cm{sup 2} spot at wavelength of 10.6 microns. The laser is capable of a pulse repetition rate up to 25 Hz, with pulse durations of about 20 microseconds. During the program basic research was conducted on the production of propulsion thrust from laser energy throughmore » heating of air and ablation of various candidate rocket propellant fuels. Flight tests with an ablation fuel (Delrin) and air were accomplished with a model Laser Lightcraft vehicle that was optimized for propulsion by the PLVTS at its maximum power output, 10 kW at 25 Hz, 400 J/pulse. Altitudes exceeding 200-feet were achieved with ablation fuels. The most recent contributions to the technology included development of a mini-thruster standard for testing of chemically enhanced fuels and theoretical calculations on the performance of formulations containing ammonium nitrate and Delrin. Results of these calculations will also be reported here.« less

Perspective on One Decade of Laser Propulsion Research at Air Force Research Laboratory

NASA Astrophysics Data System (ADS)

Larson, C. William

2008-04-01

The Air Force Laser Propulsion Program spanned nearly 10-years and included about 35-weeks of experimental research with the Pulsed Laser Vulnerability Test System of the High Energy Laser Systems Test Facility at White Sands Missile Range, New Mexico, WSMR/HELSTF/PLVTS. PLVTS is a pulsed CO2 laser that produces up to 10 kW of power in ˜10 cm2 spot at wavelength of 10.6 microns. The laser is capable of a pulse repetition rate up to 25 Hz, with pulse durations of about 20 microseconds. During the program basic research was conducted on the production of propulsion thrust from laser energy through heating of air and ablation of various candidate rocket propellant fuels. Flight tests with an ablation fuel (Delrin) and air were accomplished with a model Laser Lightcraft vehicle that was optimized for propulsion by the PLVTS at its maximum power output, 10 kW at 25 Hz, 400 J/pulse. Altitudes exceeding 200-feet were achieved with ablation fuels. The most recent contributions to the technology included development of a mini-thruster standard for testing of chemically enhanced fuels and theoretical calculations on the performance of formulations containing ammonium nitrate and Delrin. Results of these calculations will also be reported here.

Laser development for optimal helicopter obstacle warning system LADAR performance

NASA Astrophysics Data System (ADS)

Yaniv, A.; Krupkin, V.; Abitbol, A.; Stern, J.; Lurie, E.; German, A.; Solomonovich, S.; Lubashitz, B.; Harel, Y.; Engart, S.; Shimoni, Y.; Hezy, S.; Biltz, S.; Kaminetsky, E.; Goldberg, A.; Chocron, J.; Zuntz, N.; Zajdman, A.

2005-04-01

Low lying obstacles present immediate danger to both military and civilian helicopters performing low-altitude flight missions. A LADAR obstacle detection system is the natural solution for enhancing helicopter safety and improving the pilot situation awareness. Elop is currently developing an advanced Surveillance and Warning Obstacle Ranging and Display (SWORD) system for the Israeli Air Force. Several key factors and new concepts have contributed to system optimization. These include an adaptive FOV, data memorization, autonomous obstacle detection and warning algorithms and the use of an agile laser transmitter. In the present work we describe the laser design and performance and discuss some of the experimental results. Our eye-safe laser is characterized by its pulse energy, repetition rate and pulse length agility. By dynamically controlling these parameters, we are able to locally optimize the system"s obstacle detection range and scan density in accordance with the helicopter instantaneous maneuver.

Satellite power system concept development and evaluation program. Volume 2: System definition

NASA Technical Reports Server (NTRS)

1981-01-01

The system level results of the system definition studies performed by NASA as a part of the Department of Energy/NASA satellite power system concept development and evaluation program are summarized. System requirements and guidelines are discussed as well as the major elements that comprise the reference system and its design options. Alternative system approaches including different system sizes, solid state amplifier (microwave) concepts, and laser power transmission system cost summaries are reviewed. An overview of the system analysis and planning efforts is included. The overall study led to the conclusion that the reference satellite power system concept is a feasible baseload source of electrical power and, within the assumed guidelines, the minimum cost per kilowatt is achieved at the maximum output of 5 gigawatts to the utility grid. Major unresolved technical issues include maximum allowable microwave power density in the ionosphere and performance/mass characteristics of laser power transmission systems.

Under-sampling in a Multiple-Channel Laser Vibrometry System

DOE Office of Scientific and Technical Information (OSTI.GOV)

Corey, Jordan

2007-03-01

Laser vibrometry is a technique used to detect vibrations on objects using the interference of coherent light with itself. Most vibrometry systems process only one target location at a time, but processing multiple locations simultaneously provides improved detection capabilities. Traditional laser vibrometry systems employ oversampling to sample the incoming modulated-light signal, however as the number of channels increases in these systems, certain issues arise such a higher computational cost, excessive heat, increased power requirements, and increased component cost. This thesis describes a novel approach to laser vibrometry that utilizes undersampling to control the undesirable issues associated with over-sampled systems. Undersamplingmore » allows for significantly less samples to represent the modulated-light signals, which offers several advantages in the overall system design. These advantages include an improvement in thermal efficiency, lower processing requirements, and a higher immunity to the relative intensity noise inherent in laser vibrometry applications. A unique feature of this implementation is the use of a parallel architecture to increase the overall system throughput. This parallelism is realized using a hierarchical multi-channel architecture based on off-the-shelf programmable logic devices (PLDs).« less

High energy diode-pumped solid-state laser development at the Central Laser Facility

NASA Astrophysics Data System (ADS)

Mason, Paul D.; Banerjee, Saumyabrata; Ertel, Klaus; Phillips, P. Jonathan; Butcher, Thomas; Smith, Jodie; De Vido, Mariastefania; Chekhlov, Oleg; Hernandez-Gomez, Cristina; Edwards, Chris; Collier, John

2016-04-01

In this paper we review the development of high energy, nanosecond pulsed diode-pumped solid state lasers within the Central Laser Facility (CLF) based on cryogenic gas cooled multi-slab ceramic Yb:YAG amplifier technology. To date two 10J-scale systems, the DiPOLE prototype amplifier and an improved DIPOLE10 system, have been developed, and most recently a larger scale system, DiPOLE100, designed to produce 100 J pulses at up to 10 Hz. These systems have demonstrated amplification of 10 ns duration pulses at 1030 nm to energies in excess of 10 J at 10 Hz pulse repetition rate, and over 100 J at 1 Hz, with optical-to-optical conversion efficiencies of up to 27%. We present an overview of the cryo-amplifier concept and compare the design features of these three systems, including details of the amplifier designs, gain media, diode pump lasers and the cryogenic gas cooling systems. The most recent performance results from the three systems are presented along with future plans for high energy DPSSL development within the CLF.

Three-dimensional laser window formation

NASA Technical Reports Server (NTRS)

Verhoff, Vincent G.

1992-01-01

The NASA Lewis Research Center has developed and implemented a unique process for forming flawless three-dimensional laser windows. These windows represent a major part of specialized, nonintrusive laser data acquisition systems used in a variety of compressor and turbine research test facilities. This report discusses in detail the aspects of three-dimensional laser window formation. It focuses on the unique methodology and the peculiarities associated with the formation of these windows. Included in this discussion are the design criteria, bonding mediums, and evaluation testing for three-dimensional laser windows.

Compound curvature laser window development

NASA Technical Reports Server (NTRS)

Verhoff, Vincent G.

1993-01-01

The NASA Lewis Research Center has developed and implemented a unique process for forming flawless compound curvature laser windows. These windows represent a major part of specialized, nonintrusive laser data acquisition systems used in a variety of compressor and turbine research test facilities. This report summarizes the main aspects of compound curvature laser window development. It is an overview of the methodology and the peculiarities associated with the formulation of these windows. Included in this discussion is new information regarding procedures for compound curvature laser window development.

Excimer laser calibration system.

PubMed

Gottsch, J D; Rencs, E V; Cambier, J L; Hall, D; Azar, D T; Stark, W J

1996-01-01

Excimer laser photoablation for refractive and therapeutic keratectomies has been demonstrated to be feasible and practicable. However, corneal laser ablations are not without problems, including the delivery and maintenance of a homogeneous beam. We have developed an excimer laser calibration system capable of characterizing a laser ablation profile. Beam homogeneity is determined by the analysis of a polymethylmethacrylate (PMMA)-based thin-film using video capture and image processing. The ablation profile is presented as a color-coded map. Interpolation of excimer calibration system analysis provides a three-dimensional representation of elevation profiles that correlates with two-dimensional scanning profilometry. Excimer calibration analysis was performed before treating a monkey undergoing phototherapeutic keratectomy and two human subjects undergoing myopic spherocylindrical photorefractive keratectomy. Excimer calibration analysis was performed before and after laser refurbishing. Laser ablation profiles in PMMA are resolved by the excimer calibration system to .006 microns/pulse. Correlations with ablative patterns in a monkey cornea were demonstrated with preoperative and postoperative keratometry using corneal topography, and two human subjects using video-keratography. Excimer calibration analysis predicted a central-steep-island ablative pattern with the VISX Twenty/Twenty laser, which was confirmed by corneal topography immediately postoperatively and at 1 week after reepithelialization in the monkey. Predicted central steep islands in the two human subjects were confirmed by video-keratography at 1 week and at 1 month. Subsequent technical refurbishing of the laser resulted in a beam with an overall increased ablation rate measured as microns/pulse with a donut ablation profile. A patient treated after repair of the laser electrodes demonstrated no central island. This excimer laser calibration system can precisely detect laser-beam ablation profiles. The calibration system correctly predicted central islands after excimer photoablation in a treated monkey cornea and in two treated human subjects. Detection of excimer-laser-beam ablation profiles may be useful for precise calibration of excimer lasers before human photorefractive and therapeutic surgery.

Spacecraft system study: A study to define the impact of laser communication systems on their host spacecraft

NASA Technical Reports Server (NTRS)

1984-01-01

The mutual influence of a laser communication system and its host spacecraft and the degree to which the mutual influence limited acquisition, tracking and pointing processes were investigated. A laser klink between a low earth orbiting (LEO) satellite and a geosynchronous earth orbiting (GEO) satellite was used as a baseline. The laser link between satellites was a generic channel transferring 500 Mbps data from the LEO to GEO using the GaAlAs laser as the laser light source. Major aspects of pointing and tracking with a satelliteborne optical system were evaluated including: (1) orbital aspects such as spacecraft relative motions, point ahead, and Sun snd Moon optical noise; (2) burst errors introduced by the electronic and optical noise levels; (3) servo system design and configurations, and the noise sources such as, sensor noise, base motion disturbances, gimbal friction torque noise; (4) an evaluation of the tracking and beacon link and the type of sensors used; (5) the function of the acquisition procedure and an evaluation of the sensors employed; and (6) an estimate of the size, weight and power needed for the satellite system.

Optically pumped isotopic ammonia laser system

DOEpatents

Buchwald, Melvin I.; Jones, Claude R.; Nelson, Leonard Y.

1982-01-01

An optically pumped isotopic ammonia laser system which is capable of producing a plurality of frequencies in the middle infrared spectral region. Two optical pumping mechanisms are disclosed, i.e., pumping on R(J) and lasing on P(J) in response to enhancement of rotational cascade lasing including stimulated Raman effects, and, pumping on R(J) and lasing on P(J+2). The disclosed apparatus for optical pumping include a hole coupled cavity and a grating coupled cavity.

Preliminary plan for a Shuttle Coherent Atmospheric Lidar Experiment (SCALE)

NASA Technical Reports Server (NTRS)

Fitzjarrald, D.; Beranek, R.; Bilbro, J.; Mabry, J.

1985-01-01

A study has been completed to define a Shuttle experiment that solves the most crucial scientific and engineering problems involved in building a satellite Doppler wind profiler for making global wind measurements. The study includes: (1) a laser study to determine the feasibility of using the existing NOAA Windvan laser in the Space Shuttle spacecraft; (2) a preliminary optics and telescope design; (3) an accommodations study including power, weight, thermal, and control system requirements; and (4) a flight trajectory and operations plan designed to accomplish the required scientific and engineering goals. The experiment will provide much-needed data on the global distribution of atmospheric aerosols and demonstrate the technique of making wind measurements from space, including scanning the laser beam and interpreting the data. Engineering accomplishments will include space qualification of the laser, development of signal processing and lag angle compensation hardware and software, and telescope and optics design. All of the results of this limited Spacelab experiment will be directly applicable to a complete satellite wind profiler for the Earth Observation System/Space Station or other free-flying satellite.

In vivo monitoring laser tissue interaction using high resolution Fourier-domain optical coherence tomography

NASA Astrophysics Data System (ADS)

Jo, Hang Chan; Shin, Dong Jun; Ahn, Jin-Chul; Chung, Phil-Sang; Kim, DaeYu

2017-02-01

Laser-induced therapies include laser ablation to remove or cut target tissue by irradiating high-power focused laser beam. These laser treatments are widely used tools for minimally invasive surgery and retinal surgical procedures in clinical settings. In this study, we demonstrate laser tissue interaction images of various sample tissues using high resolution Fourier-domain optical coherence tomography (Fd-OCT). We use a Q-switch diode-pumped Nd:YVO4 nanosecond laser (532nm central wavelength) with a 4W maximum output power at a 20 kHz repetition rate to ablate in vitro and in vivo samples including chicken breast and mouse ear tissues. The Fd-OCT system acquires time-series Bscan images at the same location during the tissue ablation experiments with 532nm laser irradiation. The real-time series of OCT cross-sectional (B-scan) images compare structural changes of 532nm laser ablation using same and different laser output powers. Laser tissue ablation is demonstrated by the width and the depth of the tissue ablation from the B-scan images.

Next-generation laser retroreflectors for GNSS, solar system exploration, geodesy, gravitational physics and earth observation

NASA Astrophysics Data System (ADS)

Dell'Agnello, S.; Boni, A.; Cantone, C.; Ciocci, E.; Martini, M.; Patrizi, G.; Tibuzzi, M.; Delle Monache, G.; Vittori, R.; Bianco, G.; Currie, D.; Intaglietta, N.; Salvatori, L.; Lops, C.; Contessa, S.; Porcelli, L.; Mondaini, C.; Tuscano, P.; Maiello, M.

2017-11-01

The SCF_Lab (Satellite/lunar/gnss laser ranging and altimetry Characterization Facility Laboratory) of INFNLNF is designed to cover virtually LRAs (Laser Retroreflector Arrays) of CCRs (Cube Corner Retroreflectors) for missions in the whole solar system, with a modular organization of its instrumentation, two redundant SCF (SCF_Lab Characterization Facilities), and an evolutionary measurement approach, including customization and potentially upgrade on-demand. See http://www.lnf.infn.it/esperimenti/etrusco/ for a general description.

Electrical and Optical Characterization System for IR Photodetectors

DTIC Science & Technology

2015-10-12

is marked using the red circles. The newly purchased equipment includes a fast HgCdTe ( MCT ) detector and a 1064 nm pulse laser. The new fast MCT ...signal-to- noise ratio. Figure 1. The block diagram of the upgraded TRPL system. The detector and laser are newly purchased. The chopper and lock...type-II superlattices (T2SL) based infrared photodetectors. Ga-free InAs/InAsSb T2SLs offer great advantages for MWIR and LWIR laser and detector

Vertical cavity surface emitting lasers based on InP and related compounds -- Bottleneck and corkscrew

DOE Office of Scientific and Technical Information (OSTI.GOV)

Iga, K.

1996-12-31

Vertical optical interconnects of LSI chips and circuit boards and multiple fiber systems may be the most interesting field related to SE lasers. From this point of view, the device should be small as possible. The future process technology for it including epitaxy and etching will drastically change the situation of SE lasers. Dome optical technologies are already introduced in various subsystems, but the arrayed microoptic technology would be very helpful for advanced systems.

Study on profile measurement of extruding tire tread by laser

NASA Astrophysics Data System (ADS)

Wang, LiangCai; Zhang, Wanping; Zhu, Weihu

1996-10-01

This paper presents a new 2D measuring system-profile measurement of extruding tire tread by laser. It includes the thickness measurement of extruding tire tread by laser and the width measurement of extruding tire tread using Moire Fringe. The system has been applied to process line of extruding tire tread. Two measuring results have been obtained. One is a standard profile picture of extruding tire tread including seven measuring values. Another one is a series of thickness and width values. When the scanning speed < 100mm/sec and total width < 800mm. The measuring errors of width < +/- 0.5mm. While the thickness range is < 40mm. The measuring errors of thickness < +/- 0.1mm.

Free-space laser communication technologies III; Proceedings of the Meeting, Los Angeles, CA, Jan. 21, 22, 1991

NASA Technical Reports Server (NTRS)

Begley, David L. (Editor); Seery, Bernard D. (Editor)

1991-01-01

The present volume on free-space laser communication technologies discusses system analysis, performance, and applications, pointing, acquisition, and tracking in beam control, laboratory demonstration systems, and transmitter and critical component technologies. Attention is given to a space station laser communication transceiver, meeting intersatellite links mission requirements by an adequate optical terminal design, an optical approach to proximity-operations communications for Space Station Freedom, and optical space-to-ground link availability assessment and diversity requirements. Topics addressed include nonmechanical steering of laser beams by multiple aperture antennas, a free-space simulator for laser transmission, heterodyne acquisition and tracking in a free-space diode laser link, and laser terminal attitude determination via autonomous star tracking. Also discussed are stability considerations in relay lens design for optical communications, liquid crystals for lasercom applications, and narrowband optical interference filters.

Cutaneous resurfacing with CO2 and erbium: YAG lasers: preoperative, intraoperative, and postoperative considerations.

PubMed

Alster, T S

1999-02-01

The development and integration of pulsed and scanned CO2 and erbium:YAG laser systems into mainstream surgical practice over the past years has revolutionized cutaneous resurfacing. These lasers are capable of delivering to skin high peak fluences to effect controlled tissue vaporization, while leaving an acceptably narrow zone of residual thermal damage. The inherent technological differences that exist between the two distant laser systems in terms of ablation depths, degree of thermal coagulation, and postoperative side-effects and complications guide patient selection and management. This article reviews the basic principles of CO2 and erbium:YAG laser resurfacing, including preoperative, intraoperative, and postoperative patient considerations. Side-effects and complications encountered after laser resurfacing are discussed with specific guidelines provided on their appropriate management. Anticipated future developments and cutting-edge research endeavors in cutaneous laser resurfacing are also briefly outlined.

Position and orientation tracking system

DOEpatents

Burks, Barry L.; DePiero, Fred W.; Armstrong, Gary A.; Jansen, John F.; Muller, Richard C.; Gee, Timothy F.

1998-01-01

A position and orientation tracking system presents a laser scanning appaus having two measurement pods, a control station, and a detector array. The measurement pods can be mounted in the dome of a radioactive waste storage silo. Each measurement pod includes dual orthogonal laser scanner subsystems. The first laser scanner subsystem is oriented to emit a first line laser in the pan direction. The second laser scanner is oriented to emit a second line laser in the tilt direction. Both emitted line lasers scan planes across the radioactive waste surface to encounter the detector array mounted on a target robotic vehicle. The angles of incidence of the planes with the detector array are recorded by the control station. Combining measurements describing each of the four planes provides data for a closed form solution of the algebraic transform describing the position and orientation of the target robotic vehicle.

Position and orientation tracking system

DOEpatents

Burks, B.L.; DePiero, F.W.; Armstrong, G.A.; Jansen, J.F.; Muller, R.C.; Gee, T.F.

1998-05-05

A position and orientation tracking system presents a laser scanning apparatus having two measurement pods, a control station, and a detector array. The measurement pods can be mounted in the dome of a radioactive waste storage silo. Each measurement pod includes dual orthogonal laser scanner subsystems. The first laser scanner subsystem is oriented to emit a first line laser in the pan direction. The second laser scanner is oriented to emit a second line laser in the tilt direction. Both emitted line lasers scan planes across the radioactive waste surface to encounter the detector array mounted on a target robotic vehicle. The angles of incidence of the planes with the detector array are recorded by the control station. Combining measurements describing each of the four planes provides data for a closed form solution of the algebraic transform describing the position and orientation of the target robotic vehicle. 14 figs.

Widely tunable (PbSn)Te lasers using etched cavities for mass production. [for infrared spectroscopic applications

NASA Technical Reports Server (NTRS)

Miller, M. D.

1980-01-01

Lead salt diode lasers are being used increasingly as tunable sources of monochromatic infrared radiation in a variety of spectroscopic systems. These devices are particularly useful, both in the laboratory and in the field, because of their high spectral brightness (compared to thermal sources) and wide spectral coverage (compared to line-tunable gas lasers). While the primary commercial application of these lasers has been for ultrahigh resolution laboratory spectroscopy, there are numerous systems applications, including laser absorbtion pollution monitors and laser heterodyne radiometers, for which diode lasers have great potential utility. Problem areas related to the wider use of these components are identified. Among these are total tuning range, mode control, and high fabrication cost. A fabrication technique which specifically addresses the problems of tuning range and cost, and which also has potential application for mode control, is reported.

Design and construction of a cost-efficient Arduino-based mirror galvanometer system for scanning optical microscopy

NASA Astrophysics Data System (ADS)

Hsu, Jen-Feng; Dhingra, Shonali; D'Urso, Brian

2017-01-01

Mirror galvanometer systems (galvos) are commonly employed in research and commercial applications in areas involving laser imaging, laser machining, laser-light shows, and others. Here, we present a robust, moderate-speed, and cost-efficient home-built galvo system. The mechanical part of this design consists of one mirror, which is tilted around two axes with multiple surface transducers. We demonstrate the ability of this galvo by scanning the mirror using a computer, via a custom driver circuit. The performance of the galvo, including scan range, noise, linearity, and scan speed, is characterized. As an application, we show that this galvo system can be used in a confocal scanning microscopy system.

Injection-seeded operation of a Q-switched Cr,Tm,Ho:YAG laser

NASA Technical Reports Server (NTRS)

Henderson, Sammy W.; Hale, Charley P.; Magee, James R.

1991-01-01

Single-frequency Tm,Ho:YAG lasers operating near 2 microns are attractive sources for several applications including eye-safe laser radar (lidar) and pumping of AgGaSe2 parametric oscillators for efficient generation of longer wavelengths. As part of a program to develop a coherent lidar system using Tm,Ho:YAG lasers, a diode laser-pumped tunable CW single-longitudinal-mode (SLM) Cr:Tm:Ho:YAG laser and a flashlamp-pumped single-transverse-mode Q-switched Cr,Tm,Ho:YAG laser were developed. The CW laser was used to injection-seed the flashlamp-pumped laser, resulting in SLM Q-switched output. Operational characteristics of the CW and Q-switched lasers and injection-seeding results are reported.

Design and Development of High-Repetition-Rate Satellite Laser Ranging System

NASA Astrophysics Data System (ADS)

Choi, Eun-Jung; Bang, Seong-Cheol; Sung, Ki-Pyoung; Lim, Hyung-Chul; Jung, Chan-Gyu; Kim, In-Yeung; Choi, Jae-Seung

2015-09-01

The Accurate Ranging System for Geodetic Observation ? Mobile (ARGO-M) was successfully developed as the first Korean mobile Satellite Laser Ranging (SLR) system in 2012, and has joined in the International Laser Ranging Service (ILRS) tracking network, DAEdeoK (DAEK) station. The DAEK SLR station was approved as a validated station in April 2014, through the ILRS station ¡°data validation¡± process. The ARGO-M system is designed to enable 2 kHz laser ranging with millimeter-level precision for geodetic, remote sensing, navigation, and experimental satellites equipped with Laser Retroreflector Arrays (LRAs). In this paper, we present the design and development of a next generation high-repetition-rate SLR system for ARGO-M. The laser ranging rate up to 10 kHz is becoming an important issue in the SLR community to improve ranging precision. To implement high-repetition-rate SLR system, the High-repetition-rate SLR operation system (HSLR-10) was designed and developed using ARGO-M Range Gate Generator (A-RGG), so as to enable laser ranging from 50 Hz to 10 kHz. HSLR-10 includes both hardware controlling software and data post-processing software. This paper shows the design and development of key technologies of high-repetition-rate SLR system. The developed system was tested successfully at DAEK station and then moved to Sejong station, a new Korean SLR station, on July 1, 2015. HSLR-10 will begin normal operations at Sejong station in the near future.

Low temperature monitoring system for subsurface barriers

DOEpatents

Vinegar, Harold J [Bellaire, TX; McKinzie, II Billy John [Houston, TX

2009-08-18

A system for monitoring temperature of a subsurface low temperature zone is described. The system includes a plurality of freeze wells configured to form the low temperature zone, one or more lasers, and a fiber optic cable coupled to at least one laser. A portion of the fiber optic cable is positioned in at least one freeze well. At least one laser is configured to transmit light pulses into a first end of the fiber optic cable. An analyzer is coupled to the fiber optic cable. The analyzer is configured to receive return signals from the light pulses.

Lessons Learned from the Advanced Topographic Laser Altimeter System

NASA Technical Reports Server (NTRS)

Garrison, Matt; Patel, Deepak; Bradshaw, Heather; Robinson, Frank; Neuberger, Dave

2016-01-01

The ICESat-2 Advanced Topographic Laser Altimeter System (ATLAS) instrument is an upcoming Earth Science mission focusing on the effects of climate change. The flight instrument passed all environmental testing at GSFC (Goddard Space Flight Center) and is now ready to be shipped to the spacecraft vendor for integration and testing. This presentation walks through the lessons learned from design, hardware, analysis and testing perspective. ATLAS lessons learned include general thermal design, analysis, hardware, and testing issues as well as lessons specific to laser systems, two-phase thermal control, and optical assemblies with precision alignment requirements.

Atmospheric lidar multi-user instrument system definition study

NASA Technical Reports Server (NTRS)

Greco, R. V. (Editor)

1980-01-01

A spaceborne lidar system for atmospheric studies was defined. The primary input was the Science Objectives Experiment Description and Evolutionary Flow Document. The first task of the study was to perform an experiment evolutionary analysis of the SEED. The second task was the system definition effort of the instrument system. The third task was the generation of a program plan for the hardware phase. The fourth task was the supporting studies which included a Shuttle deficiency analysis, a preliminary safety hazard analysis, the identification of long lead items, and development studies required. As a result of the study an evolutionary Lidar Multi-User Instrument System (MUIS) was defined. The MUIS occupies a full Spacelab pallet and has a weight of 1300 kg. The Lidar MUIS laser provides a 2 joule frequency doubled Nd:YAG laser that can also pump a tuneable dye laser wide frequency range and bandwidth. The MUIS includes a 1.25 meter diameter aperture Cassegrain receiver, with a moveable secondary mirror to provide precise alignment with the laser. The receiver can transmit the return signal to three single and multiple photomultiple tube detectors by use of a rotating fold mirror. It is concluded that the Lidar MUIS proceed to program implementation.

A Simple Laser Induced Breakdown Spectroscopy (LIBS) System for Use at Multiple Levels in the Undergraduate Chemistry Curriculum

ERIC Educational Resources Information Center

Randall, David W.; Hayes, Ryan T.; Wong, Peter A.

2013-01-01

A LIBS (laser induced breakdown spectroscopy) spectrometer constructed by the instructor is reported for use in undergraduate analytical chemistry experiments. The modular spectrometer described here is based on commonly available components including a commercial Nd:YAG laser and a compact UV-vis spectrometer. The modular approach provides a…

Laser diagnostics for NTP fuel corrosion studies

NASA Technical Reports Server (NTRS)

Wantuck, Paul J.; Butt, D. P.; Sappey, A. D.

1993-01-01

Viewgraphs and explanations on laser diagnostics for nuclear thermal propulsion (NTP) fuel corrosion studies are presented. Topics covered include: NTP fuels; U-Zr-C system corrosion products; planar laser-induced fluorescence (PLIF); utilization of PLIF for corrosion product characterization of nuclear thermal rocket fuel elements under test; ZrC emission spectrum; and PLIF imaging of ZrC plume.

Key techniques for space-based solar pumped semiconductor lasers

NASA Astrophysics Data System (ADS)

He, Yang; Xiong, Sheng-jun; Liu, Xiao-long; Han, Wei-hua

2014-12-01

In space, the absence of atmospheric turbulence, absorption, dispersion and aerosol factors on laser transmission. Therefore, space-based laser has important values in satellite communication, satellite attitude controlling, space debris clearing, and long distance energy transmission, etc. On the other hand, solar energy is a kind of clean and renewable resources, the average intensity of solar irradiation on the earth is 1353W/m2, and it is even higher in space. Therefore, the space-based solar pumped lasers has attracted much research in recent years, most research focuses on solar pumped solid state lasers and solar pumped fiber lasers. The two lasing principle is based on stimulated emission of the rare earth ions such as Nd, Yb, Cr. The rare earth ions absorb light only in narrow bands. This leads to inefficient absorption of the broad-band solar spectrum, and increases the system heating load, which make the system solar to laser power conversion efficiency very low. As a solar pumped semiconductor lasers could absorb all photons with energy greater than the bandgap. Thus, solar pumped semiconductor lasers could have considerably higher efficiencies than other solar pumped lasers. Besides, solar pumped semiconductor lasers has smaller volume chip, simpler structure and better heat dissipation, it can be mounted on a small satellite platform, can compose satellite array, which can greatly improve the output power of the system, and have flexible character. This paper summarizes the research progress of space-based solar pumped semiconductor lasers, analyses of the key technologies based on several application areas, including the processing of semiconductor chip, the design of small and efficient solar condenser, and the cooling system of lasers, etc. We conclude that the solar pumped vertical cavity surface-emitting semiconductor lasers will have a wide application prospects in the space.

Feasibility Study of Interstellar Missions Using Laser Sail Probes Ranging in Size from the Nano to the Macro

NASA Technical Reports Server (NTRS)

Malroy, Eric T.

2010-01-01

This paper presents the analysis examining the feasibility of interstellar travel using laser sail probes ranging in size from the nano to the macro. The relativistic differential equations of motion for a laser sail are set up and solved using the Pasic Method. The limitations of the analysis are presented and discussed. The requirements for the laser system are examined, including the thermal analysis of the laser sails. Black holes, plasma fields, atmospheric collisions and sun light are several methods discussed to enable the deceleration of the interstellar probe. A number of novel mission scenarios are presented including the embryonic transport of plant life as a precursor to the arrival of space colonies

Review of technological advancements in calibration systems for laser vision correction

NASA Astrophysics Data System (ADS)

Arba-Mosquera, Samuel; Vinciguerra, Paolo; Verma, Shwetabh

2018-02-01

Using PubMed and our internal database, we extensively reviewed the literature on the technological advancements in calibration systems, with a motive to present an account of the development history, and latest developments in calibration systems used in refractive surgery laser systems. As a second motive, we explored the clinical impact of the error introduced due to the roughness in ablation and its corresponding effect on system calibration. The inclusion criterion for this review was strict relevance to the clinical questions under research. The existing calibration methods, including various plastic models, are highly affected by various factors involved in refractive surgery, such as temperature, airflow, and hydration. Surface roughness plays an important role in accurate measurement of ablation performance on calibration materials. The ratio of ablation efficiency between the human cornea and calibration material is very critical and highly dependent on the laser beam characteristics and test conditions. Objective evaluation of the calibration data and corresponding adjustment of the laser systems at regular intervals are essential for the continuing success and further improvements in outcomes of laser vision correction procedures.

Modeling of ground based laser propagation to low Earth orbit object for maneuver

NASA Astrophysics Data System (ADS)

Smith, Liam C.; Allen, Jeffrey H.; Bold, Matthew M.

2017-08-01

The Space Environment Research Centre (SERC) endeavors to demonstrate the ability to maneuver high area to mass ratio objects using ground based lasers. Lockheed Martin has been leading system performance modeling for this project that includes high power laser propagation through the atmosphere, target interactions and subsequent orbital maneuver of the object. This paper will describe the models used, model assumptions and performance estimates for laser maneuver demonstration.

Development of a wavelength stabilized seed laser system for an airborne water vapour lidar experiment

NASA Astrophysics Data System (ADS)

Schwarzer, H.; Börner, A.; Fix, A.; Günther, B.; Hübers, H.-W.; Raugust, M.; Schrandt, F.; Wirth, M.

2007-09-01

At the German Aerospace Center an airborne multi-wavelength differential absorption LIDAR for the measurement of atmospheric water vapour is currently under development. This instrument will enable the retrieval of the complete humidity profile from the surface up to the lowermost stratosphere with high vertical and horizontal resolution at a systematic error below 5%. The LIDAR will work in the wavelength region around 935 nm at three different water vapour absorption lines and one reference wavelength. A major sub-system of this instrument is a highly frequency stabilized seed laser system for the optical parametrical oscillators which generate the narrowband high energy light pulses. The development of the seed laser system includes the control software, the electronic control unit and the opto-mechanical layout. The seed lasers are Peltier-cooled distributed feedback laser diodes with bandwidths of about 30 MHz, each one operating for 200 μs before switching to the next one. The required frequency stability is +/- 30 MHz ≅ +/- 10 -4 nm under the rough environmental conditions aboard an aircraft. It is achieved by locking the laser wavelength to a water vapour absorption line. The paper describes the opto-mechanical layout of the seed laser system, the stabilization procedure and the results obtained with this equipment.

Construction of a system for single-cell transgene induction in Caenorhabditis elegans using a pulsed infrared laser

PubMed Central

Churgin, Matthew A.; He, Liping; Murray, John I.; Fang-Yen, Christopher

2014-01-01

The spatial and temporal control of transgene expression is an important tool in C. elegans biology. We previously described a method for evoking gene expression in arbitrary cells by using a focused pulsed infrared laser to induce a heat shock response (Churgin et al 2013). Here we describe detailed methods for building and testing a system for performing single-cell heat shock. Steps include setting up the laser and associated components, coupling the laser beam to a microscope, and testing heat shock protocols. All steps can be carried out using readily available off-the-shelf components. PMID:24835576

Luminescent characteristics study of Mather-type dense plasma focus and applications to short-wavelength optical pumping. Final technical report, 1 May 1984-30 September 1985

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kim, K.K.

A Mather-type dense plasma focus (MDPF) system was designed, built, and tested specifically to study its luminescent characteristics and to assess its potential as a new light source of high-energy, short-wavelength lasers. The luminescence study of MDPF showed that the conversion efficiency from the electrical input to the optical output energies is at least 50%, up to the time the plasma compression is complete. Using the system, for the first time as an optical pump, laser activities were successfully obtained from a variety of liquid organic dyes. Diagnostic capabilities included an optical multichannel analyzer system complete with a computer control,more » a nitrogen-pumped tunable dye-laser system, a high-speed streak/framing camera, a digital laser energy meter, voltage and current probes, and a computer-based data-acquisition system.« less

Reversing the pump dependence of a laser at an exceptional point

PubMed Central

Brandstetter, M.; Liertzer, M.; Deutsch, C.; Klang, P.; Schöberl, J.; Türeci, H. E.; Strasser, G.; Unterrainer, K.; Rotter, S.

2014-01-01

When two resonant modes in a system with gain or loss coalesce in both their resonance position and their width, a so-called exceptional point occurs, which acts as a source of non-trivial physics in a diverse range of systems. Lasers provide a natural setting to study such non-Hermitian degeneracies, as they feature resonant modes and a gain material as their basic constituents. Here we show that exceptional points can be conveniently induced in a photonic molecule laser by a suitable variation of the applied pump. Using a pair of coupled microdisk quantum cascade lasers, we demonstrate that in the vicinity of these exceptional points the coupled laser shows a characteristic reversal of its pump dependence, including a strongly decreasing intensity of the emitted laser light for increasing pump power. PMID:24925314

Refractive Index Seen by a Probe Beam Interacting with a Laser-Plasma System

NASA Astrophysics Data System (ADS)

Turnbull, D.; Goyon, C.; Kemp, G. E.; Pollock, B. B.; Mariscal, D.; Divol, L.; Ross, J. S.; Patankar, S.; Moody, J. D.; Michel, P.

2017-01-01

We report the first complete set of measurements of a laser-plasma optical system's refractive index, as seen by a second probe laser beam, as a function of the relative wavelength shift between the two laser beams. Both the imaginary and real refractive index components are found to be in good agreement with linear theory using plasma parameters measured by optical Thomson scattering and interferometry; the former is in contrast to previous work and has implications for crossed-beam energy transfer in indirect-drive inertial confinement fusion, and the latter is measured for the first time. The data include the first demonstration of a laser-plasma polarizer with 85 %- 87 % extinction for the particular laser and plasma parameters used in this experiment, complementing the existing suite of high-power, tunable, and ultrafast plasma-based photonic devices.

Refractive Index Seen by a Probe Beam Interacting with a Laser-Plasma System.

PubMed

Turnbull, D; Goyon, C; Kemp, G E; Pollock, B B; Mariscal, D; Divol, L; Ross, J S; Patankar, S; Moody, J D; Michel, P

2017-01-06

We report the first complete set of measurements of a laser-plasma optical system's refractive index, as seen by a second probe laser beam, as a function of the relative wavelength shift between the two laser beams. Both the imaginary and real refractive index components are found to be in good agreement with linear theory using plasma parameters measured by optical Thomson scattering and interferometry; the former is in contrast to previous work and has implications for crossed-beam energy transfer in indirect-drive inertial confinement fusion, and the latter is measured for the first time. The data include the first demonstration of a laser-plasma polarizer with 85%-87% extinction for the particular laser and plasma parameters used in this experiment, complementing the existing suite of high-power, tunable, and ultrafast plasma-based photonic devices.

Initial experiments with a laser driven Stirling engine

NASA Technical Reports Server (NTRS)

Byer, R. L.

1976-01-01

Operation of a Beale free piston Stirling engine with a 40-W CO2 laser is described. Advantages of such a system include: closed-cycle operation, long life, inexpensive construction, and size scalability to 100 MW.

Hybrid Laser-Arc Welding of the High-Strength Shipbuilding Steels: Equipment and Technology

NASA Astrophysics Data System (ADS)

Turichin, G.; Kuznetsov, M.; Tsibulskiy, I.; Firsova, A.

Hybrid laser-arc welding (HLAW) allows getting weld joints with thickness up to 35 mm for one pass, provide good quality formation of joints, minimal thermal deformations, the productivity in 10 times more in comparison with arc welding. In addition, replacement arc welding to the HLAW allows economizing filler materials, shielding gas and consumable electricity more than 4 times. Therefore, HLAW is actually technology for basic engineering branches and especially for shipbuilding. The Institute of Laser and Welding Technologies (ILWT) developed laser and hybrid laser-arc welding technologies for different type of steels and alloys including high-strength shipbuilding steels. Also ILWT produced portal and robotic systems for HLAW process realization. Portal system for hybrid laser-arc welding of panels with dimensions 6x6 m using at the manufacturing of flat curvilinear sections in the shipbuilding is depicted in the article. Results of experimental researches of the hybrid laser-arc welding parameters influence on the formation and mechanical properties of weld joint are described at the publication also. Experimental part was made with using of the portal system.

Space Applications Industrial Laser System (SAILS)

NASA Technical Reports Server (NTRS)

Mccay, T. D.; Bible, J. B.; Mueller, R. E.

1993-01-01

A program is underway to develop a YAG laser based materials processing workstation to fly in the cargo bay of the Space Shuttle. This workstation, called Space Applications Industrial Laser System (SAILS), will be capable of cutting and welding steel, aluminum, and Inconel alloys of the type planned for use in constructing the Space Station Freedom. As well as demonstrating the ability of a YAG laser to perform remote (fiber-optic delivered) repair and fabrication operations in space, fundamental data will be collected on these interactions for comparison with terrestrial data and models. The flight system, scheduled to fly in 1996, will be constructed as three modules using standard Get-Away-Special (GAS) canisters. The first module holds the laser head and cooling system, while the second contains a high peak power electrical supply. The third module houses the materials processing workstation and the command and data acquisition subsystems. The laser head and workstation cansisters are linked by a fiber-optic cable to transmit the laser light. The team assembled to carry out this project includes Lumonics Industrial Products (laser), Tennessee Technological University (structural analysis and fabrication), Auburn University Center for Space Power (electrical engineering), University of Waterloo (low-g laser process consulting), and CSTAR/UTSI (data acquisition, control, software, integration, experiment design). This report describes the SAILS program and highlights recent activities undertaken at CSTAR.

Multi-Wavelength Laser Transmitter for the Two-Step Laser Time-of-Flight Mass Spectrometer

NASA Technical Reports Server (NTRS)

Yu, Anthony W.; Li, Steven X.; Fahey, Molly E.; Grubisic, Andrej; Farcy, Benjamin J.; Uckert, Kyle; Li, Xiang; Getty, Stephanie

2017-01-01

Missions to diverse Outer Solar System bodies will require investigations that can detect a wide range of organics in complex mixtures, determine the structure of selected molecules, and provide powerful insights into their origin and evolution. Previous studies from remote spectroscopy of the Outer Solar System showed a diverse population of macromolecular species that are likely to include aromatic and conjugated hydrocarbons with varying degrees of methylation and nitrile incorporation. In situ exploration of Titan's upper atmosphere via mass and plasma spectrometry has revealed a complex mixture of organics. Similar material is expected on the Ice Giants, their moons, and other Outer Solar System bodies, where it may subsequently be deposited onto surface ices. It is evident that the detection of organics on other planetary surfaces provides insight into the chemical and geological evolution of a Solar System body of interest and can inform our understanding of its potential habitability. We have developed a prototype two-step laser desorption/ionization time-of-flight mass spectrometer (L2MS) instrument by exploiting the resonance-enhanced desorption of analyte. We have successfully demonstrated the ability of the L2MS to detect hydrocarbons in organically-doped analog minerals, including cryogenic Ocean World-relevant ices and mixtures. The L2MS instrument operates by generating a neutral plume of desorbed analyte with an IR desorption laser pulse, followed at a delay by a ultraviolet (UV) laser pulse, ionizing the plume. Desorption of the analyte, including trace organic species, may be enhanced by selecting the wavelength of the IR desorption laser to coincide with IR absorption features associated with vibration transitions of minerals or organic functional groups. In this effort, a preliminary laser developed for the instrument uses a breadboard mid-infrared (MIR) desorption laser operating at a discrete 3.475 µm wavelength, and a breadboard UV ionization laser operating at a wavelength of 266 nm. The MIR wavelength was selected to overlap the C-H stretch vibrational transition of certain aromatic hydrocarbons, and the UV wavelength provides additional selectivity to aromatic species via UV resonance-enhanced multiphoton ionization effects. The use of distinct laser wavelengths allows efficient coupling to the vibrational and electronic spectra of the analyte in independent desorption and ionization steps, mitigating excess energy that can lead to fragmentation during the ionization process and leading to selectivity that can aid in data interpretation.

Injection seeded, diode pumped regenerative ring Nd:YAG amplifier for spaceborne laser ranging technology development

NASA Technical Reports Server (NTRS)

Coyle, D. Barry; Kay, Richard B.; Degnan, John J.; Krebs, Danny J.; Seery, Bernard D.

1992-01-01

A small, all solid state, regenerative ring amplifier designed as a prototype for space application is discussed. Novel features include dual side pumping of the Nd:YAG crystal and a triangular ring cavity design which minimizes the number of optical components and losses. The amplifier is relatively small (3 ns round trip time) even though standard optical elements are employed. The ring regeneratively amplifies a 100 ps single pulse by approximately 10(exp 5) at a repetition rate of 10 to 100 Hz. The amplifier is designed to be injection seeded with a pulsed, 100 ps laser diode at 1.06 microns, but another Nd:YAG laser system supplying higher pulse energies was employed for laboratory experiment. This system is a prototype laser oscillator for the Geoscience Laser Ranging System (GLRS) platform. Results on measurements of beam quality, astigmatism, and gain are given.

Experimental observation of different soliton types in a net-normal group-dispersion fiber laser.

PubMed

Feng, Zhongyao; Rong, Qiangzhou; Qiao, Xueguang; Shao, Zhihua; Su, Dan

2014-09-20

Different soliton types are observed in a net-normal group-dispersion fiber laser based on nonlinear polarization rotation for passive mode locking. The proposed laser can deliver a dispersion-managed soliton, typical dissipation solitons, and a quasi-harmonic mode-locked pulse, a soliton bundle, and especially a dark pulse by only appropriately adjusting the linear cavity phase delay bias using one polarization controller at the fixed pump power. These nonlinear waves show different features, including the spectral shapes and time traces. The experimental observations show that the five soliton types could exist in the same laser cavity, which implies that integrable systems, dissipative systems, and dark pulse regimes can transfer and be switched in a passively mode-locked laser. Our studies not only verify the numeral simulation of the different soliton-types formation in a net-normal group-dispersion operation but also provide insight into Ginzburg-Landau equation systems.

Relay telescope for high power laser alignment system

DOEpatents

Dane, C. Brent; Hackel, Lloyd; Harris, Fritz B.

2006-09-19

A laser system includes an optical path having an intracavity relay telescope with a telescope focal point for imaging an output of the gain medium between an image location at or near the gain medium and an image location at or near an output coupler for the laser system. A kinematic mount is provided within a vacuum chamber, and adapted to secure beam baffles near the telescope focal point. An access port on the vacuum chamber is adapted for allowing insertion and removal of the beam baffles. A first baffle formed using an alignment pinhole aperture is used during alignment of the laser system. A second tapered baffle replaces the alignment aperture during operation and acts as a far-field baffle in which off angle beams strike the baffle a grazing angle of incidence, reducing fluence levels at the impact areas.

2 micron femtosecond fiber laser

DOEpatents

Liu, Jian; Wan, Peng; Yang, Lihmei

2014-07-29

Methods and systems for generating femtosecond fiber laser pulses are disclose, including generating a signal laser pulse from a seed laser oscillator; using a first amplifier stage comprising an input and an output, wherein the signal laser pulse is coupled into the input of the first stage amplifier and the output of the first amplifier stage emits an amplified and stretched signal laser pulse; using an amplifier chain comprising an input and an output, wherein the amplified and stretched signal laser pulse from the output of the first amplifier stage is coupled into the input of the amplifier chain and the output of the amplifier chain emits a further amplified, stretched signal laser pulse. Other embodiments are described and claimed.

Ultra-short wavelength x-ray system

DOEpatents

Umstadter, Donald [Ann Arbor, MI; He, Fei [Ann Arbor, MI; Lau, Yue-Ying [Potomac, MD

2008-01-22

A method and apparatus to generate a beam of coherent light including x-rays or XUV by colliding a high-intensity laser pulse with an electron beam that is accelerated by a synchronized laser pulse. Applications include x-ray and EUV lithography, protein structural analysis, plasma diagnostics, x-ray diffraction, crack analysis, non-destructive testing, surface science and ultrafast science.

Laser interferometer for space-based mapping of Earth's gravity field

NASA Astrophysics Data System (ADS)

Dehne, Marina; Sheard, Benjamin; Gerberding, Oliver; Mahrdt, Christoph; Heinzel, Gerhard; Danzmann, Karsten

2010-05-01

Laser interferometry will play a key role in the next generation of GRACE-type satellite gravity missions. The measurement concepts for future missions include a heterodyne laser interferometer. Furthermore, it is favourable to use polarising components in the laser interferometer for beam splitting. In the first step the influence of these components on the interferometer sensitivity has been investigated. Additionally, a length stability on a nm-scale has been validated. The next step will include a performance test of an interferometric SST system in an active symmetric transponder setup including two lasers and two optical benches. The design and construction of a quasi-monolithic interferometer for comparing the interferometric performance of non-polarising and polarising optics will be discussed. The results of the interferometric readout of a heterodyne configuration together with polarising optics will be presented to fulfil the phase sensitivity requirement of 1nm/√Hz-- for a typical SSI scenario.

Dust-concentration measurement based on Mie scattering of a laser beam

PubMed Central

Yu, Xiaoyu; Shi, Yunbo; Wang, Tian; Sun, Xu

2017-01-01

To realize automatic measurement of the concentration of dust particles in the air, a theory for dust concentration measurement was developed, and a system was designed to implement the dust concentration measurement method based on laser scattering. In the study, the principle of dust concentration detection using laser scattering is studied, and the detection basis of Mie scattering theory is determined. Through simulation, the influence of the incident laser wavelength, dust particle diameter, and refractive index of dust particles on the scattered light intensity distribution are obtained for determining the scattered light intensity curves of single suspended dust particles under different characteristic parameters. A genetic algorithm was used to study the inverse particle size distribution, and the reliability of the measurement system design is proven theoretically. The dust concentration detection system, which includes a laser system, computer circuitry, air flow system, and control system, was then implemented according to the parameters obtained from the theoretical analysis. The performance of the designed system was evaluated. Experimental results show that the system performance was stable and reliable, resulting in high-precision automatic dust concentration measurement with strong anti-interference ability. PMID:28767662

Alignment system for SGII-Up laser facility

NASA Astrophysics Data System (ADS)

Gao, Yanqi; Cui, Yong; Li, Hong; Gong, Lei; Lin, Qiang; Liu, Daizhong; Zhu, Baoqiang; Ma, Weixin; Zhu, Jian; Lin, Zunqi

2018-03-01

The SGII-Up laser facility in Shanghai is one of the most important high-power laser facilities in China. It is designed to obtain 24 kJ (3ω) of energy with a square pulse of 3 ns using eight laser beams (two bundles). To satisfy the requirements for the safety, efficiency, and quality, an alignment system is developed for this facility. This alignment system can perform automatic alignment of the preamplifier system, main amplifier system, and harmonic conversion system within 30 min before every shot during the routine operation of the facility. In this article, an overview of the alignment system is first presented. Then, its alignment characteristics are discussed, along with the alignment process. Finally, experimental results, including the alignment results and the facility performance, are reported. The results show that the far-field beam pointing alignment accuracy is better than 3 μrad, and the alignment error of the near-field beam centering is no larger than 1 mm. These satisfy the design requirements very well.

Videodisc-Computer Interfaces.

ERIC Educational Resources Information Center

Zollman, Dean

1984-01-01

Lists microcomputer-videodisc interfaces currently available from 26 sources, including home use systems connected through remote control jack and industrial/educational systems utilizing computer ports and new laser reflective and stylus technology. Information provided includes computer and videodisc type, language, authoring system, educational…

Development of highly compact and low power consumption athermal military laser designators

NASA Astrophysics Data System (ADS)

Sijan, A.

2012-10-01

The utility of military lasers, particularly in the area of laser designation for laser-guided weapons, is well understood. Laser systems based on Nd:YAG have been fielded since the 1980's and over the last three decades have introduced incremental technology steps to improve performance and weight. The most recent technology step has been the introduction of athermal lasers based on laser-diode pumping of Nd:YAG and products are now emerging for use on the battlefield. The technical performance, efficiency, size, weight and power for these lasers, has been key to driving the new production designs. In this paper, we review the development of the laser designs and their introduction since the advent of laser designation. In particular, we compare the relative performance and characteristics over the evolution of fielded laser designators. Moreover, we will review the key building blocks for the design of athermal lasers and describe some critical design issues for engineering and productionisation of a military laser system, including removal of thermal lensing, novel diode-pumping schemes and robustness over the environment. These will be exemplified using results from the development of the SELEX Galileo Type 163 Laser Target Designators. These will cover not only technical performance, power and efficiency, but also thermal management, mass, volume, cost and overall complexity for manufacture.

Space Transfer Concepts and Analyses for Exploration Missions. Technical Directive 12: Beamed Power Systems Study

NASA Technical Reports Server (NTRS)

Eder, D.

1992-01-01

Parametric models were constructed for Earth-based laser powered electric orbit transfer from low Earth orbit to geosynchronous orbit. These models were used to carry out performance, cost/benefit, and sensitivity analyses of laser-powered transfer systems including end-to-end life cycle cost analyses for complete systems. Comparisons with conventional orbit transfer systems were made indicating large potential cost savings for laser-powered transfer. Approximate optimization was done to determine best parameter values for the systems. Orbit transfer flights simulations were conducted to explore effects of parameters not practical to model with a spreadsheet. The simulations considered view factors that determine when power can be transferred from ground stations to an orbit transfer vehicle and conducted sensitivity analyses for numbers of ground stations, Isp including dual-Isp transfers, and plane change profiles. Optimal steering laws were used for simultaneous altitude and plane change. Viewing geometry and low-thrust orbit raising were simultaneously simulated. A very preliminary investigation of relay mirrors was made.

Laser Journal

NASA Astrophysics Data System (ADS)

1991-12-01

The major results of an experimental study of a slab Nd:YAG laser are reported in the article; the laser was successfully developed by the authors. The major findings include the following: (1) a method for cooling the blended flowing air and water, as well the related experimental parameters; (2) by using a crossed lens cavity, the authors further improved the anomalous capability within the compensation cavity of the slab laser, as well as higher insensitivity of the system to maladjustment; and (3) a processing technique and major points of slab YAG laser medium.

Tenth Biennial Coherent Laser Radar Technology and Applications Conference

NASA Technical Reports Server (NTRS)

Kavaya, Michael J. (Compiler)

1999-01-01

The tenth conference on coherent laser radar technology and applications is the latest in a series beginning in 1980 which provides a forum for exchange of information on recent events current status, and future directions of coherent laser radar (or lidar or lader) technology and applications. This conference emphasizes the latest advancement in the coherent laser radar field, including theory, modeling, components, systems, instrumentation, measurements, calibration, data processing techniques, operational uses, and comparisons with other remote sensing technologies.

Visible Laser Research One Meter Device

DTIC Science & Technology

1980-01-01

OF THIS PAGE (" ol ~n Date Entered) ~z, TABLE OF CONTENTS Section Page List of Illustrations 3 I. INTRODUCTION 5 II. BACKGROUND 15 III. RESULTS 17 A...proven lasers are the excip!ex lasers which include the rare gas halides, halogens and mercury halides (see Table I). Of these exciplex systems, there...Stokes line routinpiy e- ported. (1) 5 Z::I~AVCO EVERETT TABLE I A SUMMARY OF EXCIPLEX LASERS AND THEIR LASING WAVELENGTHS EXCIPLEX , (B -+ X) nm ArF

Flow Visualization and Laser Velocimetry for Wind Tunnels

NASA Technical Reports Server (NTRS)

Hunter, W. W., Jr. (Editor); Foughner, J. T., Jr. (Editor)

1982-01-01

The need for flow visualization and laser velocimetry were discussed. The purpose was threefold: (1) provide a state-of-the-art overview; (2) provide a forum for industry, universities, and government agencies to address problems in developing useful and productive flow visualization and laser velocimetry measurement techniques; and (3) provide discussion of recent developments and applications of flow visualization and laser velocimetry measurement techniques and instrumentation systems for wind tunnels including the 0.3-Meter Transonic Cryogenic Tunnel.

Harmonically mode-locked erbium-doped waveguide laser

NASA Astrophysics Data System (ADS)

Fanto, Michael L.; Malowicki, John E.; Bussjager, Rebecca J.; Johns, Steven T.; Vettese, Elizabeth K.; Hayduk, Michael J.

2004-08-01

The generation of ultrastable picosecond pulses in the 1550 nm range is required for numerous applications that include photonic analog-to-digital converter systems and high-bit rate optical communication systems. Mode-locked erbium-doped fiber ring lasers (EDFLs) are typically used to generate pulses at this wavelength. In addition to timing stability and output power, the physical size of the laser cavity is of primary importance to the Air Force. The length of the erbium (Er)-doped fiber used as the gain medium may be on the order of meters or even tens of meters which adds complexity to packaging. However, with the recent advancements in the production of multi-component glasses, higher doping concentrations can be achieved as compared to silicate glasses. Even more recent is the introduction of Er-doped multi-component glass waveguides, thus allowing the overall footprint of the gain medium to be reduced. We have constructed a novel harmonically mode-locked fiber ring laser using the Er-doped multi-component glass waveguide as the gain medium. The performance characteristics of this Er-doped waveguide laser (EDWL) including pulse width, spectral width, harmonic suppression, optical output power, laser stability and single sideband residual phase noise will be discussed in this paper.

Modulated and continuous-wave operations of low-power thulium (Tm:YAP) laser in tissue welding

NASA Astrophysics Data System (ADS)

Bilici, Temel; Tabakoğlu, Haşim Özgür; Topaloğlu, Nermin; Kalaycıoğlu, Hamit; Kurt, Adnan; Sennaroglu, Alphan; Gülsoy, Murat

2010-05-01

Our aim is to explore the welding capabilities of a thulium (Tm:YAP) laser in modulated and continuous-wave (CW) modes of operation. The Tm:YAP laser system developed for this study includes a Tm:YAP laser resonator, diode laser driver, water chiller, modulation controller unit, and acquisition/control software. Full-thickness incisions on Wistar rat skin were welded by the Tm:YAP laser system at 100 mW and 5 s in both modulated and CW modes of operation (34.66 W/cm2). The skin samples were examined during a 21-day healing period by histology and tensile tests. The results were compared with the samples closed by conventional suture technique. For the laser groups, immediate closure at the surface layers of the incisions was observed. Full closures were observed for both modulated and CW modes of operation at day 4. The tensile forces for both modulated and CW modes of operation were found to be significantly higher than the values found by conventional suture technique. The 1980-nm Tm:YAP laser system operating in both modulated and CW modes maximizes the therapeutic effect while minimizing undesired side effects of laser tissue welding. Hence, it is a potentially important alternative tool to the conventional suturing technique.

Next generation diode lasers with enhanced brightness

NASA Astrophysics Data System (ADS)

Ried, S.; Rauch, S.; Irmler, L.; Rikels, J.; Killi, A.; Papastathopoulos, E.; Sarailou, E.; Zimer, H.

2018-02-01

High-power diode lasers are nowadays well established manufacturing tools in high power materials processing, mainly for tactile welding, surface treatment and cladding applications. Typical beam parameter products (BPP) of such lasers range from 30 to 50 mm·mrad at several kilowatts of output power. TRUMPF offers a product line of diode lasers to its customers ranging from 150 W up to 6 kW of output power. These diode lasers combine high reliability with small footprint and high efficiency. However, up to now these lasers are limited in brightness due to the commonly used spatial and coarse spectral beam combining techniques. Recently diode lasers with enhanced brightness have been presented by use of dense wavelength multiplexing (DWM). In this paper we report on TRUMPF's diode lasers utilizing DWM. We demonstrate a 2 kW and a 4 kW system ideally suited for fine welding and scanner welding applications. The typical laser efficiency is in the range of 50%. The system offers plug and play exchange of the fiber beam delivery cable, multiple optical outputs and integrated cooling in a very compact package. An advanced control system offers flexible integration in any customer's shop floor environment and includes industry 4.0 capabilities (e.g. condition monitoring and predictive maintenance).

Atmospheric effects on laser eye safety and damage to instrumentation

NASA Astrophysics Data System (ADS)

Zilberman, Arkadi; Kopeika, Natan S.

2017-10-01

Electro-optical sensors as well as unprotected human eyes are extremely sensitive to laser radiation and can be permanently damaged from direct or reflected beams. Laser detector/eye hazard depends on the interaction between the laser beam and the media in which it traverses. The environmental conditions including terrain features, atmospheric particulate and water content, and turbulence, may alter the laser's effect on the detector/eye. It is possible to estimate the performance of an electro-optical system as long as the atmospheric propagation of the laser beam can be adequately modeled. More recent experiments and modeling of atmospheric optics phenomena such as inner scale effect, aperture averaging, atmospheric attenuation in NIR-SWIR, and Cn2 modeling justify an update of previous eye/detector safety modeling. In the present work, the influence of the atmospheric channel on laser safety for personnel and instrumentation is shown on the basis of theoretical and experimental data of laser irradiance statistics for different atmospheric conditions. A method for evaluating the probability of damage and hazard distances associated with the use of laser systems in a turbulent atmosphere operating in the visible and NIR-SWIR portions of the electromagnetic spectrum is presented. It can be used as a performance prediction model for directed energy engagement of ground-based or air-based systems.

Soliton microcomb range measurement

NASA Astrophysics Data System (ADS)

Suh, Myoung-Gyun; Vahala, Kerry J.

2018-02-01

Laser-based range measurement systems are important in many application areas, including autonomous vehicles, robotics, manufacturing, formation flying of satellites, and basic science. Coherent laser ranging systems using dual-frequency combs provide an unprecedented combination of long range, high precision, and fast update rate. We report dual-comb distance measurement using chip-based soliton microcombs. A single pump laser was used to generate dual-frequency combs within a single microresonator as counterpropagating solitons. We demonstrated time-of-flight measurement with 200-nanometer precision at an averaging time of 500 milliseconds within a range ambiguity of 16 millimeters. Measurements at distances up to 25 meters with much lower precision were also performed. Our chip-based source is an important step toward miniature dual-comb laser ranging systems that are suitable for photonic integration.

Active solution of homography for pavement crack recovery with four laser lines.

PubMed

Xu, Guan; Chen, Fang; Wu, Guangwei; Li, Xiaotao

2018-05-08

An active solution method of the homography, which is derived from four laser lines, is proposed to recover the pavement cracks captured by the camera to the real-dimension cracks in the pavement plane. The measurement system, including a camera and four laser projectors, captures the projection laser points on the 2D reference in different positions. The projection laser points are reconstructed in the camera coordinate system. Then, the laser lines are initialized and optimized by the projection laser points. Moreover, the plane-indicated Plücker matrices of the optimized laser lines are employed to model the laser projection points of the laser lines on the pavement. The image-pavement homography is actively determined by the solutions of the perpendicular feet of the projection laser points. The pavement cracks are recovered by the active solution of homography in the experiments. The recovery accuracy of the active solution method is verified by the 2D dimension-known reference. The test case with the measurement distance of 700 mm and the relative angle of 8° achieves the smallest recovery error of 0.78 mm in the experimental investigations, which indicates the application potentials in the vision-based pavement inspection.

Development of three-axis inkjet printer for gear sensors

NASA Astrophysics Data System (ADS)

Iba, Daisuke; Rodriguez Lopez, Ricardo; Kamimoto, Takahiro; Nakamura, Morimasa; Miura, Nanako; Iizuka, Takashi; Masuda, Arata; Moriwaki, Ichiro; Sone, Akira

2016-04-01

The long-term objective of our research is to develop sensor systems for detection of gear failure signs. As a very first step, this paper proposes a new method to create sensors directly printed on gears by a printer and conductive ink, and shows the printing system configuration and the procedure of sensor development. The developing printer system is a laser sintering system consisting of a laser and CNC machinery. The laser is able to synthesize micro conductive patterns, and introduced to the CNC machinery as a tool. In order to synthesize sensors on gears, we first design the micro-circuit pattern on a gear through the use of 3D-CAD, and create a program (G-code) for the CNC machinery by CAM. This paper shows initial experiments with the laser sintering process in order to obtain the optimal parameters for the laser setting. This new method proposed here may provide a new manufacturing process for mechanical parts, which have an additional functionality to detect failure, and possible improvements include creating more economical and sustainable systems.

Multiscale spectral nanoscopy

DOEpatents

Yang, Haw; Welsher, Kevin

2016-11-15

A system and method for non-invasively tracking a particle in a sample is disclosed. The system includes a 2-photon or confocal laser scanning microscope (LSM) and a particle-holding device coupled to a stage with X-Y and Z position control. The system also includes a tracking module having a tracking excitation laser, X-Y and Z radiation-gathering components configured to detect deviations of the particle in an X-Y and Z directions. The system also includes a processor coupled to the X-Y and Z radiation gathering components, generate control signals configured to drive the stage X-Y and Z position controls to track the movement of the particle. The system may also include a synchronization module configured to generate LSM pixels stamped with stage position and a processing module configured to generate a 3D image showing the 3D trajectory of a particle using the LSM pixels stamped with stage position.

Design of a dual species atom interferometer for space

NASA Astrophysics Data System (ADS)

Schuldt, Thilo; Schubert, Christian; Krutzik, Markus; Bote, Lluis Gesa; Gaaloul, Naceur; Hartwig, Jonas; Ahlers, Holger; Herr, Waldemar; Posso-Trujillo, Katerine; Rudolph, Jan; Seidel, Stephan; Wendrich, Thijs; Ertmer, Wolfgang; Herrmann, Sven; Kubelka-Lange, André; Milke, Alexander; Rievers, Benny; Rocco, Emanuele; Hinton, Andrew; Bongs, Kai; Oswald, Markus; Franz, Matthias; Hauth, Matthias; Peters, Achim; Bawamia, Ahmad; Wicht, Andreas; Battelier, Baptiste; Bertoldi, Andrea; Bouyer, Philippe; Landragin, Arnaud; Massonnet, Didier; Lévèque, Thomas; Wenzlawski, Andre; Hellmig, Ortwin; Windpassinger, Patrick; Sengstock, Klaus; von Klitzing, Wolf; Chaloner, Chris; Summers, David; Ireland, Philip; Mateos, Ignacio; Sopuerta, Carlos F.; Sorrentino, Fiodor; Tino, Guglielmo M.; Williams, Michael; Trenkel, Christian; Gerardi, Domenico; Chwalla, Michael; Burkhardt, Johannes; Johann, Ulrich; Heske, Astrid; Wille, Eric; Gehler, Martin; Cacciapuoti, Luigi; Gürlebeck, Norman; Braxmaier, Claus; Rasel, Ernst

2015-06-01

Atom interferometers have a multitude of proposed applications in space including precise measurements of the Earth's gravitational field, in navigation & ranging, and in fundamental physics such as tests of the weak equivalence principle (WEP) and gravitational wave detection. While atom interferometers are realized routinely in ground-based laboratories, current efforts aim at the development of a space compatible design optimized with respect to dimensions, weight, power consumption, mechanical robustness and radiation hardness. In this paper, we present a design of a high-sensitivity differential dual species 85Rb/87Rb atom interferometer for space, including physics package, laser system, electronics and software. The physics package comprises the atom source consisting of dispensers and a 2D magneto-optical trap (MOT), the science chamber with a 3D-MOT, a magnetic trap based on an atom chip and an optical dipole trap (ODT) used for Bose-Einstein condensate (BEC) creation and interferometry, the detection unit, the vacuum system for 10-11 mbar ultra-high vacuum generation, and the high-suppression factor magnetic shielding as well as the thermal control system. The laser system is based on a hybrid approach using fiber-based telecom components and high-power laser diode technology and includes all laser sources for 2D-MOT, 3D-MOT, ODT, interferometry and detection. Manipulation and switching of the laser beams is carried out on an optical bench using Zerodur bonding technology. The instrument consists of 9 units with an overall mass of 221 kg, an average power consumption of 608 W (814 W peak), and a volume of 470 liters which would well fit on a satellite to be launched with a Soyuz rocket, as system studies have shown.

Novel Space-based Solar Power Technologies and Architectures for Earth and Beyond

NASA Technical Reports Server (NTRS)

Howell, Joe T.; Fikes, John C.; O'Neill, Mark J.

2005-01-01

Research, development and studies of novel space-based solar power systems, technologies and architectures for Earth and beyond are needed to reduce the cost of clean electrical power for terrestrial use and to provide a stepping stone for providing an abundance of power in space, i.e., manufacturing facilities, tourist facilities, delivery of power between objects in space, and between space and surface sites. The architectures, technologies and systems needed for space to Earth applications may also be used for in-space applications. Advances in key technologies, i.e., power generation, power management and distribution, power beaming and conversion of beamed power are needed to achieve the objectives of both terrestrial and extraterrestrial applications. Power beaming or wireless power transmission (WPT) can involve lasers or microwaves along with the associated power interfaces. Microwave and laser transmission techniques have been studied with several promising approaches to safe and efficient WPT identified. These investigations have included microwave phased array transmitters, as well as laser transmission and associated optics. There is a need to produce "proof-of-concept" validation of critical WPT technologies for both the near-term, as well as far-term applications. Investments may be harvested in near-term beam safe demonstrations of commercial WPT applications. Receiving sites (users) include ground-based stations for terrestrial electrical power, orbital sites to provide power for satellites and other platforms, future space elevator systems, space vehicle propulsion, and space to surface sites. This paper briefly discusses achieving a promising approach to the solar power generation and beamed power conversion. The approach is based on a unique high-power solar concentrator array called Stretched Lens Array (SLA) for both solar power generation and beamed power conversion. Since both versions (solar and laser) of SLA use many identical components (only the photovoltaic cells need to be different), economies of manufacturing and scale may be realized by using SLA on both ends of the laser power beaming system in a space solar power application. Near-term uses of this SLA-laser-SLA system may include terrestrial and space exploration in near Earth space. Later uses may include beamed power for bases or vehicles on Mars.

Proposed SLR Optical Bench Required to Track Debris Using 1550 nm Lasers

NASA Technical Reports Server (NTRS)

Shappirio, M.; Coyle, D. B.; McGarry, J. F.; Bufton, J.; Cheek, J. W.; Clarke, G.; Hull, S. M.; Skillman, D. R.; Stysley, P. R.; Sun, X.;

Mars Laser Communication Demonstration, Artist's Concept

NASA Technical Reports Server (NTRS)

2005-01-01

This illustration depicts a concept for operation of an optical communications system on NASA's Mars Telecommunications Orbiter. The orbiter is in development for launch in September 2009 with a payload including the spacecraft terminal of the Mars Laser Communication Demonstration Project. This project will also include an Earth-based terminal for two-way, high-data-rate communication using infrared light. The orbiter's primary communications with Earth will use radio frequencies. The laser demonstration is intended to build experience for use in decisions about possible use of optical communications by later missions.

Acousto-optic devices for operation with 2μm fibre lasers

NASA Astrophysics Data System (ADS)

Ward, J. D.; Stevens, G.; Shardlow, P. C.

2016-03-01

Fibre lasers operating in the 2μm region are of increasing interest for a range of applications, including laser machining and biomedical systems. The large mode area compared to 1μm fibre lasers combined with operation in an "eye-safe" region of the spectrum makes them particularly attractive. When developing fibre lasers at 1μm and 1·5μm manufacturers were able to call upon enabling technologies used by the telecoms industry, but at longer wavelengths, including 2μm, many such components are either unavailable or immature. We report on recent developments of Acousto-Optic Modulators and Tunable Filters that are specifically optimised for use with fibre systems operating at or around 2μm. AO devices are interesting due to their ability to conserve spatial-coherence, making them appropriate for use with single-mode optical fibres. We describe how the choice of interaction medium is an important consideration, particularly affecting the drive power and the polarisation behaviour of the device - the latter being an important parameter when used in a fibre system. We also describe two designs of AO Tunable Filter intended for laser tuning. Both designs have been demonstrated intracavity in 2μm fibre lasers. The first gives exceptionally narrow resolution (δλ/λ<0·1%). The second design is of a novel type of AOTF where a matched pair of AOTFs is configured to give a substantially net zero frequency-shift with little or no loss of pointing stability, any minor deviations in manufacture being self-compensated. Furthermore, small controlled frequency-shifts (up to about 10kHz) may be introduced with little or no detriment to the alignment of the system.

Linear laser diode arrays for improvement in optical disk recording for space stations

NASA Technical Reports Server (NTRS)

Alphonse, G. A.; Carlin, D. B.; Connolly, J. C.

1990-01-01

The design and fabrication of individually addressable laser diode arrays for high performance magneto-optic recording systems are presented. Ten diode arrays with 30 mW cW light output, linear light vs. current characteristics and single longitudinal mode spectrum were fabricated using channel substrate planar (CSP) structures. Preliminary results on the inverse CSP structure, whose fabrication is less critically dependent on device parameters than the CSP, are also presented. The impact of systems parameters and requirements, in particular, the effect of feedback on laser design is assessed, and techniques to reduce feedback or minimize its effect on systems performance, including mode-stabilized structures, are evaluated.

Optical characterization in wide spectral range by a coherent spectrophotometer

NASA Astrophysics Data System (ADS)

Sirutkaitis, Valdas; Eckardt, Robert C.; Balachninaite, Ona; Grigonis, Rimantas; Melninkaitis, A.; Rakickas, T.

2003-11-01

We report on the development and use of coherent spectrophotometers specialized for the unusual requirements of characterizing nonlinear optical materials and multilayer dielectric coatings used in laser systems. A large dynamic range is required to measure the linear properties of transmission, reflection and absorption and nonlinear properties of laser-induced damage threshold and nonlinear frequency conversion. Optical parametric oscillators generate coherent radiation that is widely tunable with instantaneous powers that can range from milliwatts to megawatts and are well matched to this application. As particular example a laser spectrophotometer based on optical parametric oscillators and a diode-pumped, Q-switched Nd:YAG laser and suitable for optical characterization in the spectral range 420-4500 nm is described. Measurements include reflectance and transmittance, absorption, scattering and laser-induced damage thresholds. Possibilities of a system based on a 130-fs Ti:sapphire laser and optical parametric generators are also discussed.

Solid state laser systems for space application

NASA Technical Reports Server (NTRS)

Kay, Richard B.

1994-01-01

Since the last report several things have happened to effect the research effort. In laser metrology, measurements using Michelson type interferometers with an FM modulated diode laser source have been performed. The discrete Fourier transform technique has been implemented. Problems associated with this technique as well as the overall FM scheme were identified. The accuracy of the technique is not at the level we would expect at this point. We are now investigating the effect of various types of noise on the accuracy as well as making changes to the system. One problem can be addressed by modifying the original optical layout. Our research effort was also expanded to include the assembly and testing of a diode pumped\\Nd:YAG laser pumped\\Ti sapphire laser for possible use in sounding rocket applications. At this stage, the diode pumped Nd:YAG laser has been assembled and made operational.

Free-space laser communication technologies IV; Proceedings of the 4th Conference, Los Angeles, CA, Jan. 23, 24, 1992

NASA Technical Reports Server (NTRS)

Begley, David L. (Editor); Seery, Bernard D. (Editor)

1992-01-01

Papers included in this volume are grouped under topics of receivers; laser transmitters; components; system analysis, performance, and applications; and beam control (pointing, acquisition, and tracking). Papers are presented on an experimental determination of power penalty contributions in an optical Costas-type phase-locked loop receiver, a resonant laser receiver for free-space laser communications, a simple low-loss technique for frequency-locking lasers, direct phase modulation of laser diodes, and a silex beacon. Particular attention is given to experimental results on an optical array antenna for nonmechanical beam steering, a potassium Faraday anomalous dispersion optical filter, a 100-Mbps resonant cavity phase modulator for coherent optical communications, a numerical simulation of a 325-Mbit/s QPPM optical communication system, design options for an optical multiple-access data relay terminal, CCD-based optical tracking loop design trades, and an analysis of a spatial-tracking subsystem for optical communications.

Infrared laser spectroscopic trace gas sensing

NASA Astrophysics Data System (ADS)

Sigrist, Markus

2016-04-01

Chemical sensing and analyses of gas samples by laser spectroscopic methods are attractive owing to several advantages such as high sensitivity and specificity, large dynamic range, multi-component capability, and lack of pretreatment or preconcentration procedures. The preferred wavelength range comprises the fundamental molecular absorption range in the mid-infared between 3 and 15 μm, whereas the near-infrared range covers the (10-100 times weaker) higher harmonics and combination bands. The availability of near-infrared and, particularly, of broadly tunable mid-infrared sources like external cavity quantum cascade lasers (EC-QCLs), interband cascade lasers (ICLs), difference frequency generation (DFG), optical parametric oscillators (OPOs), recent developments of diode-pumped lead salt semiconductor lasers, of supercontinuum sources or of frequency combs have eased the implementation of laser-based sensing devices. Sensitive techniques for molecular absorption measurements include multipass absorption, various configurations of cavity-enhanced techniques such as cavity ringdown (CRD), or of photoacoustic spectroscopy (PAS) including quartz-enhanced (QEPAS) or cantilever-enhanced (CEPAS) techniques. The application requirements finally determine the optimum selection of laser source and detection scheme. In this tutorial talk I shall discuss the basic principles, present various experimental setups and illustrate the performance of selected systems for chemical sensing of selected key atmospheric species. Applications include an early example of continuous vehicle emission measurements with a mobile CO2-laser PAS system [1]. The fast analysis of C1-C4 alkanes at sub-ppm concentrations in gas mixtures is of great interest for the petrochemical industry and was recently achieved with a new type of mid-infrared diode-pumped piezoelectrically tuned lead salt vertical external cavity surface emitting laser (VECSEL) [2]. Another example concerns measurements on short-lived species like nitrous acid (HONO) with a QCL-based QEPAS system where the small gas sampling volume and hence short gas residence time are of particular importance [3]. A true analysis of gas mixtures has been performed with a widely tunable DFG system in a medical application that could also be adapted to atmospheric species [4]. It is demonstrated that a laser-based narrowband system with broad tunability combined with an appropriate detection scheme is feasible for the chemical analysis of multi-component gas mixtures even with an a priori unknown composition. Most recent examples will further confirm the great potential of infrared laser-based devices for trace species sensing. References 1. D. Marinov and M.W. Sigrist: "Monitoring of road-traffic emission with mobile photoacoustic system", Photochem. and Photobiol. Sciences 2, 774-778 (2003) 2. J.M. Rey, M. Fill, F. Felder and M.W. Sigrist: "Broadly tunable mid-infrared VECSEL for multiple components hydrocarbons gas sensing", Appl. Phys. B 117, 935-939 (2014) 3. H. Yi, R. Maamary, X. Gao, M.W. Sigrist, E. Fertein, and W. Chen: "Short-lived species detection of nitrous acid by external-cavity quantum cascade laser based quartz-enhanced photoacoustic absorption spectroscopy", Appl. Phys. Lett. 106, 101109 (2015) 4. M. Gianella and M.W. Sigrist: "Chemical Analysis of Surgical Smoke by Infrared Laser Spectroscopy", Appl. Phys. B 109, 485-496 (2012)

Method for pulse control in a laser including a stimulated brillouin scattering mirror system

DOEpatents

Dane, C. Brent; Hackel, Lloyd; Harris, Fritz B.

2007-10-23

A laser system, such as a master oscillator/power amplifier system, comprises a gain medium and a stimulated Brillouin scattering SBS mirror system. The SBS mirror system includes an in situ filtered SBS medium that comprises a compound having a small negative non-linear index of refraction, such as a perfluoro compound. An SBS relay telescope having a telescope focal point includes a baffle at the telescope focal point which blocks off angle beams. A beam splitter is placed between the SBS mirror system and the SBS relay telescope, directing a fraction of the beam to an alternate beam path for an alignment fiducial. The SBS mirror system has a collimated SBS cell and a focused SBS cell. An adjustable attenuator is placed between the collimated SBS cell and the focused SBS cell, by which pulse width of the reflected beam can be adjusted.

Carbon Nanotube Activities at NASA-Johnson Space Center

NASA Technical Reports Server (NTRS)

Arepalli, Sivaram

2006-01-01

Research activities on carbon nanotubes at NASA-Johnson Space Center include production, purification, characterization and their applications for human space flight. In-situ diagnostics during nanotube production by laser oven process include collection of spatial and temporal data of passive emission and laser induced fluorescence from C2, C3 and Nickel atoms in the plume. Details of the results from the "parametric study" of the pulsed laser ablation process indicate the effect of production parameters including temperature, buffer gas, flow rate, pressure, and laser fluence. Improvement of the purity by a variety of steps in the purification process is monitored by characterization techniques including SEM, TEM, Raman, UV-VIS-NIR and TGA. A recently established NASA-JSC protocol for SWCNT characterization is undergoing revision with feedback from nanotube community. Efforts at JSC over the past five years in composites have centered on structural polymednanotube systems. Recent activities broadened this focus to multifunctional materials, supercapacitors, fuel cells, regenerable CO2 absorbers, electromagnetic shielding, radiation dosimetry and thermal management systems of interest for human space flight. Preliminary tests indicate improvement of performance in most of these applications because of the large surface area as well as high electrical and thermal conductivity exhibited by SWCNTs.

Safety approaches for high power modular laser operation

NASA Astrophysics Data System (ADS)

Handren, R. T.

1993-03-01

Approximately 20 years ago, a program was initiated at the Lawrence Livermore National Laboratory (LLNL) to study the feasibility of using lasers to separate isotopes of uranium and other materials. Of particular interest was the development of a uranium enrichment method for the production of commercial nuclear power reactor fuel to replace current more expensive methods. The Uranium Atomic Vapor Laser Isotope Separation (U-AVLIS) Program progressed to the point where a plant-scale facility to demonstrate commercial feasibility was built and is being tested. The U-AVLIS Program uses copper vapor lasers which pump frequency selective dye lasers to photoionize uranium vapor produced by an electron beam. The selectively ionized isotopes are electrostatically collected. The copper lasers are arranged in oscillator/amplifier chains. The current configuration consists of 12 chains, each with a nominal output of 800 W for a system output in excess of 9 kW. The system requirements are for continuous operation (24 h a day, 7 days a week) and high availability. To meet these requirements, the lasers are designed in a modular form allowing for rapid change-out of the lasers requiring maintenance. Since beginning operation in early 1985, the copper lasers have accumulated over 2 million unit hours at a greater than 90% availability. The dye laser system provides approximately 2.5 kW average power in the visible wavelength range. This large-scale laser system has many safety considerations, including high-power laser beams, high voltage, and large quantities (approximately 3000 gal) of ethanol dye solutions. The Laboratory's safety policy requires that safety controls be designed into any process, equipment, or apparatus in the form of engineering controls. Administrative controls further reduce the risk to an acceptable level. Selected examples of engineering and administrative controls currently being used in the U-AVLIS Program are described.

Imaging strategies for the study of gas turbine spark ignition

NASA Astrophysics Data System (ADS)

Gord, James R.; Tyler, Charles; Grinstead, Keith D., Jr.; Fiechtner, Gregory J.; Cochran, Michael J.; Frus, John R.

1999-10-01

Spark-ignition systems play a critical role in the performance of essentially all gas turbine engines. These devices are responsible for initiating the combustion process that sustains engine operation. Demanding applications such as cold start and high-altitude relight require continued enhancement of ignition systems. To characterize advanced ignition systems, we have developed a number of laser-based diagnostic techniques configured for ultrafast imaging of spark parameters including emission, density, temperature, and species concentration. These diagnostics have been designed to exploit an ultrafast- framing charge-coupled-device (CCD) camera and high- repetition-rate laser sources including mode-locked Ti:sapphire oscillators and regenerative amplifiers. Spontaneous-emission and laser-shlieren measurements have been accomplished with this instrumentation and the result applied to the study of a novel Unison Industries spark igniter that shows great promise for improved cold-start and high-altitude-relight capability as compared to that of igniters currently in use throughout military and commercial fleets. Phase-locked and ultrafast real-time imaging strategies are explored, and details of the imaging instrumentation, particularly the CCD camera and laser sources, are discussed.

LASER Tech Briefs, September 1993. Volume 1, No. 1

NASA Technical Reports Server (NTRS)

Schnirring, Bill (Editor)

1993-01-01

This edition of LASER Tech briefs contains a feature on photonics. The other topics include: Electronic Components and Circuits. Electronic Systems, Physical Sciences, Materials, Computer Programs, Mechanics, Machinery, Fabrication Technology, Mathematics and Information Sciences, Life Sciences and books and reports.

Source technology as the foundation for modern infra-red counter measures (IRCM)

NASA Astrophysics Data System (ADS)

Grasso, Robert J.

2010-10-01

Protection of military aircraft from IR guided threats is paramount to ensure the survivability of aircrews, platforms, and to ensure mission success. At the foundation of all IRCM systems is the source; that component that provides the in-band radiant energy required for threat defeat. As such, source technology has evolved with IRCM technology to encompass the evolving systems architectures that encompass IRCM: 1) "Hot Brick" omni-directional sources; 2) arc lamps, and; 3) lasers. Lasers, as IRCM sources continue to evolve to meet the challenges of ever-evolving threats, superior techniques, economy of installation, and superior source technology. Lasers represent the single greatest advance in IRCM source technology and continue to evolve to meet ever more sophisticated threats. And have been used with great effect in all modern IRCM systems; evolving from frequency doubled CO2 lasers, to solid state lasers with OPOs, to semiconductor lasers including Quantum Cascade Lasers (QCLs); these last devices represent the latest advance in IRCM source technology offering all-band coverage, architectural simplicity, and economy of scale. While QCLs represent the latest advance in IRCM laser technology, fiber lasers show much promise in addressing multi-band operation as well as the ability to be coherently combined to achieve even greater output capability. Also, ultra-short pulse lasers are evolving to become practical for IRCM applications. Stay tuned ......

FY14 LLNL OMEGA Experimental Programs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Heeter, R. F.; Fournier, K. B.; Baker, K.

In FY14, LLNL’s High-Energy-Density Physics (HED) and Indirect Drive Inertial Confinement Fusion (ICF-ID) programs conducted several campaigns on the OMEGA laser system and on the EP laser system, as well as campaigns that used the OMEGA and EP beams jointly. Overall these LLNL programs led 324 target shots in FY14, with 246 shots using just the OMEGA laser system, 62 shots using just the EP laser system, and 16 Joint shots using Omega and EP together. Approximately 31% of the total number of shots (62 OMEGA shots, 42 EP shots) shots supported the Indirect Drive Inertial Confinement Fusion Campaign (ICF-ID).more » The remaining 69% (200 OMEGA shots and 36 EP shots, including the 16 Joint shots) were dedicated to experiments for High- Energy-Density Physics (HED). Highlights of the various HED and ICF campaigns are summarized in the following reports.« less

Smart spectroscopy sensors: II. Narrow-band laser systems

NASA Astrophysics Data System (ADS)

Matharoo, Inderdeep; Peshko, Igor

2013-03-01

This paper describes the principles of operation of a miniature multifunctional optical sensory system based on laser technology and spectroscopic principles of analysis. The operation of the system as a remote oxygen sensor has been demonstrated. The multi-component alarm sensor has been designed to recognise gases and to measure gas concentration (O2, CO2, CO, CH4, N2O, C2H2, HI, OH radicals and H2O vapour, including semi-heavy water), temperature, pressure, humidity, and background radiation from the environment. Besides gas sensing, the same diode lasers are used for range-finding and to provide sensor self-calibration. The complete system operates as an inhomogeneous sensory network: the laser sensors are capable of using information received from environmental sensors for improving accuracy and reliability of gas concentration measurement. The sources of measurement errors associated with hardware and algorithms of operation and data processing have been analysed in detail.

Multiphoton microscopy system with a compact fiber-based femtosecond-pulse laser and handheld probe

PubMed Central

Liu, Gangjun; Kieu, Khanh; Wise, Frank W.; Chen, Zhongping

2012-01-01

We report on the development of a compact multiphoton microscopy (MPM) system that integrates a compact and robust fiber laser with a miniature probe. The all normal dispersion fiber femtosecond laser has a central wavelength of 1.06 μm, pulse width of 125 fs and average power of more than 1 W. A double cladding photonic crystal fiber was used to deliver the excitation beam and to collect the two-photon signal. The hand-held probe included galvanometer-based mirror scanners, relay lenses and a focusing lens. The packaged probe had a diameter of 16 mm. Second harmonic generation (SHG) images and two-photon excited fluorescence (TPEF) images of biological tissues were demonstrated using the system. MPM images of different biological tissues acquired by the compact system which integrates an FBFP laser, an DCPCF and a miniature handheld probe. PMID:20635426

FY15 LLNL OMEGA Experimental Programs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Heeter, R. F.; Baker, K. L.; Barrios, M. A.

In FY15, LLNL’s High-Energy-Density Physics (HED) and Indirect Drive Inertial Confinement Fusion (ICF-ID) programs conducted several campaigns on the OMEGA laser system and on the EP laser system, as well as campaigns that used the OMEGA and EP beams jointly. Overall these LLNL programs led 468 target shots in FY15, with 315 shots using just the OMEGA laser system, 145 shots using just the EP laser system, and 8 Joint shots using Omega and EP together. Approximately 25% of the total number of shots (56 OMEGA shots and 67 EP shots, including the 8 Joint shots) supported the Indirect Drivemore » Inertial Confinement Fusion Campaign (ICF-ID). The remaining 75% (267 OMEGA shots and 86 EP shots) were dedicated to experiments for High-Energy-Density Physics (HED). Highlights of the various HED and ICF campaigns are summarized in the following reports.« less

A solar-pumped Nd:YAG laser in the high collection efficiency regime

NASA Astrophysics Data System (ADS)

Lando, Mordechai; Kagan, Jacob; Linyekin, Boris; Dobrusin, Vadim

2003-07-01

Solar-pumped lasers can be used for space and terrestrial applications. We report on solar side-pumped Nd:YAG laser experiments, which included comprehensive beam quality measurements and demonstrated record collection efficiency and day long operation. A 6.75 m 2 segmented primary mirror was mounted on a commercial two-axis positioner and focused the solar radiation towards a stationary non-imaging-optics secondary concentrator, which illuminated a Nd:YAG laser rod. Solar side-pumped laser experiments were conducted in both the low and the high pumping density regimes. The low density system was composed of a 89 × 98-mm 2 aperture two-dimensional compound parabolic concentrator (CPC) and a 10-mm diameter 130-mm long Nd:YAG laser rod. The laser emitted up to 46 W and operated continuously for 5 h. The high density system was composed of a three-dimensional CPC with 98 mm entrance diameter and 24 mm exit diameter, followed by a two-dimensional CPC with a rectangular 24 × 33 mm 2 aperture. It pumped a 6-mm diameter 72 mm long Nd:YAG laser rod, which emitted up to 45 W. The results constitute a record collection efficiency of 6.7 W/m 2 of primary mirror. We compare the current results to previous solar side-pumped laser experiments, including experiments at higher pumping density but with low collection efficiency. Finally, we present a scaled up design for a 400 W laser pumped by a solar collection area of 60 m 2, incorporating simultaneously high collection efficiency and high pumping density.

A High-efficiency, Small, Solid-state Laser for Pyrotechnic Ignition

NASA Technical Reports Server (NTRS)

Yang, L. C.; Menichelli, V. J.

1973-01-01

A completely self-contained, small, neodymium laser has been designed and demonstrated for use in a pyrotechnic ignition system. A nominal 16 J of laser energy (1.06 micron wavelength, 1-ms duration) was achieved in a rectangular 10.5-X 15.1-X 25.4-cm package weighting 5.14 kg. This high energy-to-weight ratio is encouraging for laser applications in which specific energy efficiency (energy per unit weight or volume) is important. The laser design concepts are described, and some results on pyrotechnic ignition are given. Some details on a laser currently under construction, which will be 1/8 the size of the above laser, are included.

Picosecond laser welding of similar and dissimilar materials.

PubMed

Carter, Richard M; Chen, Jianyong; Shephard, Jonathan D; Thomson, Robert R; Hand, Duncan P

2014-07-01

We report picosecond laser welding of similar and dissimilar materials based on plasma formation induced by a tightly focused beam from a 1030 nm, 10 ps, 400 kHz laser system. Specifically, we demonstrate the welding of fused silica, borosilicate, and sapphire to a range of materials including borosilicate, fused silica, silicon, copper, aluminum, and stainless steel. Dissimilar material welding of glass to aluminum and stainless steel has not been previously reported. Analysis of the borosilicate-to-borosilicate weld strength compares well to those obtained using similar welding systems based on femtosecond lasers. There is, however, a strong requirement to prepare surfaces to a high (10-60 nm Ra) flatness to ensure a successful weld.

Improving the Reliability and Modal Stability of High Power 870 nm AlGaAs CSP Laser Diodes for Applications to Free Space Communication Systems

NASA Technical Reports Server (NTRS)

Connolly, J. C.; Alphonse, G. A.; Carlin, D. B.; Ettenberg, M.

1991-01-01

The operating characteristics (power-current, beam divergence, etc.) and reliability assessment of high-power CSP lasers is discussed. The emission wavelength of these lasers was optimized at 860 to 880 nm. The operational characteristics of a new laser, the inverse channel substrate planar (ICSP) laser, grown by metalorganic chemical vapor deposition (MOCVD), is discussed and the reliability assessment of this laser is reported. The highlights of this study include a reduction in the threshold current value for the laser to 15 mA and a degradation rate of less than 2 kW/hr for the lasers operating at 60 mW of peak output power.

High-efficiency high-brightness diode lasers at 1470 nm/1550 nm for medical and defense applications

NASA Astrophysics Data System (ADS)

Gallup, Kendra; Ungar, Jeff; Vaissie, Laurent; Lammert, Rob; Hu, Wentao

2012-03-01

Diode lasers in the 1400 nm to 1600 nm regime are used in a variety of applications including pumping Er:YAG lasers, range finding, materials processing, aesthetic medical treatments and surgery. In addition to the compact size, efficiency, and low cost advantages of traditional diode lasers, high power semiconductor lasers in the eye-safe regime are becoming widely used in an effort to minimize the unintended impact of potentially hazardous scattered optical radiation from the laser source, the optical delivery system, or the target itself. In this article we describe the performance of high efficiency high brightness InP laser bars at 1470nm and 1550nm developed at QPC Lasers for applications ranging from surgery to rangefinding.

Adiabatic Soliton Laser

NASA Astrophysics Data System (ADS)

Bednyakova, Anastasia; Turitsyn, Sergei K.

2015-03-01

The key to generating stable optical pulses is mastery of nonlinear light dynamics in laser resonators. Modern techniques to control the buildup of laser pulses are based on nonlinear science and include classical solitons, dissipative solitons, parabolic pulses (similaritons) and various modifications and blending of these methods. Fiber lasers offer remarkable opportunities to apply one-dimensional nonlinear science models for the design and optimization of very practical laser systems. Here, we propose a new concept of a laser based on the adiabatic amplification of a soliton pulse in the cavity—the adiabatic soliton laser. The adiabatic change of the soliton parameters during evolution in the resonator relaxes the restriction on the pulse energy inherent in traditional soliton lasers. Theoretical analysis is confirmed by extensive numerical modeling.

Structural Mineral Physics at Extreme Conditions

NASA Astrophysics Data System (ADS)

Chariton, S.; Dubrovinsky, L. S.; Dubrovinskaia, N.

2017-12-01

Laser heating techniques in diamond anvil cells (DACs) cover a wide pressure-temperature range - above 300 GPa and up to 5000 K. Recent advantages in on-line laser heating techniques resulted in a significant improvement of reliability of in situ X-ray powder diffraction studies in laser-heated DACs, which have become routine at a number of synchrotron facilities including specialized beam-lines at the 3rd generation synchrotrons. However, until recently, existing DAC laser-heating systems could not be used for structural X-ray diffraction studies aimed at structural refinements, i.e. measuring of the diffraction intensities, and not only at determining of lattice parameters. The reason is that in existing DAC laser-heating facilities the laser beam enters the cell at a fixed angle, and a partial rotation of the DAC, as required in monochromatic structural X-ray diffraction experiments, results in a loss of the target crystal and may be even dangerous if the powerful laser light starts to scatter in arbitrary directions by the diamond anvils. In order to overcome this problem we have develop a portable laser heating system and implement it at different diffraction beam lines. We demonstrate the application of this system for simultaneous high-pressure and high-temperature powder and single crystal diffraction studies using examples of studies of chemical and phase relations in the Fe-O system, transition metals carbonates, and silicate perovskites.

Development of safe infrared gas lasers

NASA Astrophysics Data System (ADS)

Mainuddin; Singhal, Gaurav; Tyagi, R. K.; Maini, A. K.

2013-04-01

Infrared gas lasers find application in numerous civil and military areas. Such lasers are therefore being developed at different institutions around the world. However, the development of chemical infrared gas lasers such as chemical oxygen iodine lasers (COIL) involves the use of several hazardous chemicals. In order to exploit full potential of these lasers, one must take diligent care of the safety issues associated with the handling of these chemicals and the involved processes. The present paper discusses the safety aspects to be taken into account in the development of these infrared gas lasers including various detection sensors working in conjunction with a customized data acquisition system loaded with safety interlocks for safe operation. The developed safety schemes may also be implemented for CO2 gas dynamic laser (GDL) and hydrogen fluoride-deuterium fluoride (HF-DF) Laser.

Assessment of Laser-Driven Pulsed Neutron Sources for Poolside Neutron-based Advanced NDE – A Pathway to LANSCE-like Characterization at INL

DOE Office of Scientific and Technical Information (OSTI.GOV)

Roth, Markus; Vogel, Sven C.; Bourke, Mark Andrew M.

A variety of opportunities for characterization of fresh nuclear fuels using thermal (~25meV) and epithermal (~10eV) neutrons have been documented at Los Alamos National Laboratory. They include spatially resolved non-destructive characterization of features, isotopic enrichment, chemical heterogeneity and stoichiometry. The LANSCE spallation neutron source is well suited in neutron fluence and temporal characteristics for studies of fuels. However, recent advances in high power short pulse lasers suggest that compact neutron sources might, over the next decade, become viable at a price point that would permit their consideration for poolside characterization on site at irradiation facilities. In a laser-driven neutron sourcemore » the laser is used to accelerate deuterium ions into a beryllium target where neutrons are produced. At this time, the technology is new and their total neutron production is approximately four orders of magnitude less than a facility like LANSCE. However, recent measurements on a sub-optimized system demonstrated >10 10 neutrons in sub-nanosecond pulses in predominantly forward direction. The compactness of the target system compared to a spallation target may allow exchanging the target during a measurement to e.g. characterize a highly radioactive sample with thermal, epithermal, and fast neutrons as well as hard X-rays, thus avoiding sample handling. At this time several groups are working on laser-driven neutron production and are advancing concepts for lasers, laser targets, and optimized neutron target/moderator systems. Advances in performance sufficient to enable poolside fuels characterization with LANSCE-like fluence on sample within a decade may be possible. This report describes the underlying physics and state-of-the-art of the laser-driven neutron production process from the perspective of the DOE/NE mission. It also discusses the development and understanding that will be necessary to provide customized capability for characterization of irradiated fuels. Potential operational advantages compared to a spallation neutron source include reduced shielding complexity, reduced energy requirements, and a production target free of fission products. Contributors to this report include experts in laser-driven neutron production (Roth, Fernandez), laser design (Haefner, Siders, Leemans), laser target design (Glenzer), spallation target/moderator design (Mocko), neutron instrumentation and characterization applications (Vogel, Bourke).« less

Next generation laser for Inertial Confinement Fusion

DOE Office of Scientific and Technical Information (OSTI.GOV)

Marshall, C.D.; Beach, J.; Bibeau, C.

1997-07-18

We are in the process of developing and building the ``Mercury`` laser system as the first in a series of a new generation of diode-pumped solid-state Inertial Confinement Fusion (ICF) lasers at LLNL. Mercury will be the first integrated demonstration of a scalable laser architecture compatible with advanced high energy density (HED) physics applications. Primary performance goals include 10% efficiencies at 10 Hz and a 1-10 ns pulse with 1{omega} energies of 100 J and with 2{omega}/3{omega} frequency conversion.

Protective laser beam viewing device

DOEpatents

Neil, George R.; Jordan, Kevin Carl

2012-12-18

A protective laser beam viewing system or device including a camera selectively sensitive to laser light wavelengths and a viewing screen receiving images from the laser sensitive camera. According to a preferred embodiment of the invention, the camera is worn on the head of the user or incorporated into a goggle-type viewing display so that it is always aimed at the area of viewing interest to the user and the viewing screen is incorporated into a video display worn as goggles over the eyes of the user.

Rugged TDLAS system for High Energy Laser atmospheric propagation characterization

NASA Astrophysics Data System (ADS)

Perram, Glen; Rice, Christopher

2008-10-01

An active remote sensing instrument for the characterization of atmospheric absorption, scattering, and scintillation at several key high energy laser wavelengths is in development. The instrument is based on narrow band tunable diode lasers fiber coupled to a 12'' Ritchey-Chretien transmit telescope and a second receive telescope with visible or near infrared imager. For example, tunable diode lasers have been used to obtain absorption spectra in the laboratory for the Cs D2 lines near 852 nm and the oxygen X-b lines near 760 nm, key to the Diode Pumped Alkali Laser (DPAL) concept. Absorbencies of less than 0.5% are observable. Applications will be assessed including effects to HEL atmospheric propagation from molecular and aerosol absorption and scattering, Cn2 estimation from atmospheric turbulence, hazardous chemical emission detection, and laser communication interception from side scattering. The system will soon be deployed to a military laser test range to characterize path lengths of greater than 1 km.

Laser Ultrasonic System for On-Line Steel Tube Gauging

NASA Astrophysics Data System (ADS)

Monchalin, Jean-Pierre; Choquet, Marc; Padioleau, Christian; Néron, Christian; Lévesque, Daniel; Blouin, Alain; Corbeil, Christian; Talbot, Richard; Bendada, Abdelhakim; Lamontagne, Mario; Kolarik, Robert V.; Jeskey, Gerald V.; Dominik, Erich D.; Duly, Larry J.; Samblanet, Kenneth J.; Agger, Steven E.; Roush, Kenneth J.; Mester, Michael L.

2003-03-01

A laser-ultrasonic system has been installed on a seamless tubing production line of The Timken Company and is being used to measure on-line the wall thickness of tubes during processing. The seamless process consists essentially in forcing a mandrel through a hot cylindrical billet in rotation and typically results in fairly large wall thickness variations that should be minimized and controlled to respect specifications. The system includes a Q-switched Nd-YAG laser for generation of ultrasound by ablation, a long pulse very stable Nd-YAG laser for detection coupled to a confocal Fabry-Perot interferometer, a pyrometer to measure tube temperature and two laser Doppler velocimeters to measure the coordinates of the probing location at the tube surface. The laser, data acquisition and processing units are housed in a cabin off line and connected to a front coupling head located over the passing tube by optical fibers. The system has been integrated into the plant computer network and provides in real time thickness data to the plant operators. It allow much faster mill setups, has been used since its deployment for inspecting more than 100,000 tubes and has demonstrated very significant savings.

Magnetically switched power supply system for lasers

NASA Technical Reports Server (NTRS)

Pacala, Thomas J. (Inventor)

1987-01-01

A laser power supply system is described in which separate pulses are utilized to avalanche ionize the gas within the laser and then produce a sustained discharge to cause the gas to emit light energy. A pulsed voltage source is used to charge a storage device such as a distributed capacitance. A transmission line or other suitable electrical conductor connects the storage device to the laser. A saturable inductor switch is coupled in the transmission line for containing the energy within the storage device until the voltage level across the storage device reaches a predetermined level, which level is less than that required to avalanche ionize the gas. An avalanche ionization pulse generating circuit is coupled to the laser for generating a high voltage pulse of sufficient amplitude to avalanche ionize the laser gas. Once the laser gas is avalanche ionized, the energy within the storage device is discharged through the saturable inductor switch into the laser to provide the sustained discharge. The avalanche ionization generating circuit may include a separate voltage source which is connected across the laser or may be in the form of a voltage multiplier circuit connected between the storage device and the laser.

Controlled feasibility trial comparing the use of 1470nm and 940nm diode laser for the treatment of hyperplastic inferior nasal turbinates

NASA Astrophysics Data System (ADS)

Sroka, Ronald; Havel, Miriam; Leunig, Andreas; Betz, Christian S.

2012-02-01

Introduction: So far various laser systems have been used for volume reduction of hyperplastic nasal turbinates. In case of endonasal application, fiber controlled diode lasers are preferred due to reasons of cost and practicability. The aim of this clinical study was to compare the coagulative tissue effects using either λ=1470nm vs. λ=940nm emitting lasers in treatment of hyperplastic inferior nasal turbinates in an intraindividual manner. Patients and methods: This prospective, randomized, double-blind, clinical feasibility trial included 20 patients suffering from hyperplastic inferior nasal turbinates. In each case, one nasal cavity was treated using 1470nm laser at 4- 5W, the other one with 940nm laser at 12W. Treatment was performed endoscopically controlled in non-contact mode. Clinical presentation and patients symptoms were documented preoperatively and on day 1, 3, 7, 14 and 21 postoperatively using rhinomanometry, standardized questionnaires including SNOT 20 GAV (German adapted version), and separate endoscopic examination respectively. Results: None of the patients showed infections, hemorrhages or other complications occurred intra- or postoperatively. The mean operation time was significantly shorter using the 1470nm diode laser as compared to the 940nm laser, thus lower energy was applied. There was a significant reduction of nasal obstruction on day 21 postoperatively compared to the preoperative condition on both sides regardless of the laser system used. Evaluation of the SNOT-Scores as assessed before and three weeks after surgery showed significant subjective improvements. Conclusion: Compared with standard application of 940nm diode laser, 1470nm diode laser application provides an equivalent tissue reduction in shorter operation time using less total energy and a comparable relief of nasal obstruction postoperatively.

Laser beam alignment and profilometry using diagnostic fluorescent safety mirrors

NASA Astrophysics Data System (ADS)

Lizotte, Todd E.

2011-03-01

There are a wide range of laser beam delivery systems in use for various purposes; including industrial and medical applications. Virtually all such beam delivery systems for practical purposes employ optical systems comprised of mirrors and lenses to shape, focus and guide the laser beam down to the material being processed. The goal of the laser beam delivery is to set the optimum parameters and to "fold" the beam path to reduce the mechanical length of the optical system, thereby allowing a physically compact system. In many cases, even a compact system can incorporate upwards of six mirrors and a comparable number of lenses all needing alignment so they are collinear. One of the major requirements for use of such systems in industry is a method of safe alignment. The alignment process requires that the aligner determine where the beam strikes each element. The aligner should also preferably be able to determine the shape or pattern of the laser beam at that point and its relative power. These alignments are further compounded in that the laser beams generated are not visible to the unaided human eye. Such beams are also often of relatively high power levels, and are thereby a significant hazard to the eyes of the aligner. Obvious an invisible beam makes it nearly impossible to align laser system without some form of optical assistance. The predominant method of visually aligning the laser beam delivery is the use of thermal paper, paper cards or fluorescing card material. The use of paper products which have limited power handling capability or coated plastics can produce significant debris and contaminants within the beam line that ultimately damage the optics. The use of the cards can also create significant laser light scatter jeopardizing the safety of the person aligning the system. This paper covers a new safety mirror design for use with at various UV and Near IR wavelengths (193 nm to 1064 nm) within laser beam delivery systems and how its use can provide benefits covering eye safety, precise alignment and beam diagnostics.

Thulium fibre laser nerve stimulation and its application in human pain research

NASA Astrophysics Data System (ADS)

Warnaby, Catherine E.

Experimental pain induction, in combination with psychophysical and functional imaging techniques, allows the controlled study of the mechanisms, pathways and brain areas involved in the processing of noxious stimuli. Laser nerve stimulation provides an excellent stimulus that selectively activates the Adelta and C nociceptors with only low concurrent activity in the warmth system. Thulium fibre laser systems, operating near 2mum, offer several advantages over other pain stimulators including the CO[2] and Tm:YAG laser systems. These advantages include direct absorption at the location of the nociceptors, reduced likelihood of tissue damage, improved compatibility with fMRI, and wavelength tunability. The main aims of the thesis were to apply an initial thulium fibre laser system to pain activation studies in healthy subjects and confirm the potential advantages. A 1D finite difference photothermal model confirmed that thulium fibre laser radiation is absorbed throughout the expected location of the nociceptors and produces a lower surface temperature than CO[2] radiation. In order to produce a temperature rise of 9°C at 150mum, thulium radiation induces a surface temperature rise of 12°C compared to 21°C surface temperature rise using CO[2] radiation. The use of thulium fibre radiation greatly reduces the likelihood of tissue damage and first-degree burns when compared to CO[2] radiation. The spatial temperature gradient and the surface temperature rise were also found to be strongly dependent on the thulium fibre laser emission wavelength, which implies that wavelength tuning may be used to obtain the optimum stimulus wavelength in the 2mum region. The 5W initial fibre laser system was fully characterised before application to human pain studies and was shown to have excellent reproducibility of the stimulus parameters, with short-term and long-term deviations of the pulse energy of 5% and 8% of the mean respectively. The thulium fibre laser emits radiation over a 38nm wavelength range from 2.006-2.044mum. The initial system was used successfully to elicit painful sensations and laser evoked potentials (LEPs), which showed the expected dependence on the laser stimulus parameters. In agreement with the modelled results, beam diameters from 5-8mm for a 150ms pulse duration were found to elicit painful responses while minimising tissue damage. Psychophysical assessment of the pain threshold energy and energy density in ten volunteers, using the modified staircase technique and the method of constant stimuli, also showed the expected dependence on the laser beam diameter over this range. The topographical distribution of the LEPs elicited by the thulium fibre laser and a CO[2] pain stimulator were found to be very similar. However, statistically significant differences in the peak latencies of the LEP components were observed. The peak latency of the N2, P2 and P3 components elicited by the thulium fibre laser were found to be longer by 44ms, 52ms and 78ms respectively than those elicited by the CO[2] laser across five volunteers. These latency differences are believed to be due to the difference in beam diameter of the two stimuli, which produces an increase in local spatial summation for the CO[2] laser stimuli. The effectiveness of the thulium fibre laser as a controlled pain stimulator for human pain research has been confirmed. Using the current thulium fibre laser stimulation system, the optimum stimulus parameters are provided by a beam diameter of 6mm and a pulse duration of 150ms. However, further application of the current system to human pain research is limited by the available output power and the delivery of the thulium radiation to the subject. Suggestions are made for further work using an improved thulium fibre laser system with an increased output power of 20W, optical fibre delivery and wavelength tuning.

Laser micro machining of medical devices.

PubMed

Rausch, Y

2009-01-01

Excimer and increasingly ultra-short-pulsed lasers are important tools in the creation of microstructures and nanostructures. Capabilities of the latest systems are described, which include drilling 30-microm diameter holes in 50 to 100 microm thick metal foils and subsurface engraving of transparent materials.

Laser Communication Experiments with Artemis Satellite

NASA Astrophysics Data System (ADS)

Kuzkov, Sergii; Sodnik, Zoran; Kuzkov, Volodymyr

2013-10-01

In November 2001, the European Space Agency (ESA) established the world-first inter-satellite laser communication link between the geostationary ARTEMIS satellite and the low Earth orbiting (LEO) SPOT-4 Earth observation satellite, demonstrating data rates of 50 Mbps. In 2006, the Japanese Space Agency launched the KIRARI (OICETS) LEO satellite with a compatible laser communication terminal and bidirectional laser communication links (50 Mbps and 2 Mbps) were successfully realized between KIRARI and ARTEMIS. ESA is now developing the European Data Relay Satellite (EDRS) system, which will use laser communication technology to transmit data between the Sentinel 1 and 2 satellites in LEO to two geostationary satellites (EDRS-A and EDRS-C) at data rates of 1.8 Gbps. As the data handling capabilities of state-of-the-art telecommunication satellites in GEO increase so is the demand for the feeder-link bandwidth to be transmitted from ground. This is why there is an increasing interest in developing high bandwidth ground-to-space laser communication systems working through atmosphere. In 2002, the Main Astronomical Observatory (MAO) started the development of its own laser communication system for its 0.7m AZT-2 telescope, located in Kyiv, Ukraine. The work was supported by the National Space Agency of Ukraine and by ESA. MAO developed a highly accurate computerized tracking system for AZT-2 telescope and a compact laser communication package called LACES (Laser Atmosphere and Communication Experiments with Satellites). The LACES instrument includes a camera of the pointing and tracking subsystems, a receiver module, a laser transmitter module, a tip/tilt atmospheric turbulence compensation subsystem, a bit error rate tester module and other optical and electronic components. The principal subsystems are mounted on a platform, which is located at the Cassegrain focus of the AZT-2 telescope. All systems were tested with the laser communication payload on-board ARTEMIS and the data analysis was supported by the telemetry received from the ARTEMIS payload control centre in Redu (Belgium). Special attention was focused on the investigation of the impact of atmosphere turbulence on laser beam propagation, especially in cloudy conditions. A description of our telescope and ground based laser system as well as the experimental results will be presented.

Bringing PW-class lasers to XFELs (Conference Presentation)

NASA Astrophysics Data System (ADS)

Tomizawa, Hiromitsu

2017-06-01

Experimental researches using high power optical lasers combined with free electron lasers (FELs) open new frontiers in high energy density (HED) sciences. Probing and pumping capabilities are dramatically improved due to the brightness of the XFEL pulses with ultrafast duration. Besides, the peak intensities of Ti:sapphire laser Chirped Pulse Amplification (CPA) systems reach petawatt (PW)-class with operating in few tens of fs and commercially available at a few Hz of repetition rate. We have been developing an experimental platform for HED sciences using high power, high intensity optical lasers at the XFEL facility, SACLA.Currently, an experimental platform with a dual 0.5 PW Ti:Sapphire laser system is under beam commissioning for experiments combined with the SACLA's x-ray beam for research objectives that require more peak power in the optical laser pulses with a few tens of fs. The optical laser system is designed to deliver two laser beams simultaneously with the maximum power of 0.5 PW in each into a target chamber located in an experimental hutch 6 (EH6) at BL2, which was recently commissioned as a SACLA's 2nd hard x-ray beamline. A focusing capability using sets of compound refractive lenses will be applied to increase the x-ray fluence on the target sample. One of the most key issues for the integrated experimental platform is development of diagnostics that meets requirements both from the high power laser (e.g. resistance to harsh environments) and from the XFEL (e.g. adaptation to the available data acquisition system). The status and future perspective of the development including automatic laser alignment systems will be reported in the presentation. We will discuss the most promising and important new physics experiments that will be enabled by the combination of PW-class lasers and the world-class FEL's x-ray beam.

Performance comparison of supersonic ejectors with different motive gas injection schemes applicable for flowing medium gas laser

NASA Astrophysics Data System (ADS)

Singhal, G.; Subbarao, P. M. V.; Mainuddin; Tyagi, R. K.; Dawar, A. L.

2017-05-01

A class of flowing medium gas lasers with low generator pressures employ supersonic flows with low cavity pressure and are primarily categorized as high throughput systems capable of being scaled up to MW class. These include; Chemical Oxygen Iodine Laser (COIL) and Hydrogen (Deuterium) Fluoride (HF/DF). The practicability of such laser systems for various applications is enhanced by exhausting the effluents directly to ambient atmosphere. Consequently, ejector based pressure recovery forms a potent configuration for open cycle operation. Conventionally these gas laser systems require at least two ejector stages with low pressure stage being more critical, since it directly entrains the laser media, and the ensuing perturbation of cavity flow, if any, may affect laser operation. Hence, the choice of plausible motive gas injection schemes viz., peripheral or central is a fluid dynamic issue of interest, and a parametric experimental performance comparison would be beneficial. Thus, the focus is to experimentally characterize the effect of variation in motive gas supply pressure, entrainment ratio, back pressure conditions, nozzle injection position operated together with a COIL device and discern the reasons for the behavior.

Visual servoing of a laser ablation based cochleostomy

NASA Astrophysics Data System (ADS)

Kahrs, Lüder A.; Raczkowsky, Jörg; Werner, Martin; Knapp, Felix B.; Mehrwald, Markus; Hering, Peter; Schipper, Jörg; Klenzner, Thomas; Wörn, Heinz

2008-03-01

The aim of this study is a defined, visually based and camera controlled bone removal by a navigated CO II laser on the promontory of the inner ear. A precise and minimally traumatic opening procedure of the cochlea for the implantation of a cochlear implant electrode (so-called cochleostomy) is intended. Harming the membrane linings of the inner ear can result in damage of remaining organ functions (e.g. complete deafness or vertigo). A precise tissue removal by a laser-based bone ablation system is investigated. Inside the borehole the pulsed laser beam is guided automatically over the bone by using a two mirror galvanometric scanner. The ablation process is controlled by visual servoing. For the detection of the boundary layers of the inner ear the ablation area is monitored by a color camera. The acquired pictures are analyzed by image processing. The results of this analysis are used to control the process of laser ablation. This publication describes the complete system including image processing algorithms and the concept for the resulting distribution of single laser pulses. The system has been tested on human cochleae in ex-vivo studies. Further developments could lead to safe intraoperative openings of the cochlea by a robot based surgical laser instrument.

Physical modeling of 3D and 4D laser imaging

NASA Astrophysics Data System (ADS)

Anna, Guillaume; Hamoir, Dominique; Hespel, Laurent; Lafay, Fabien; Rivière, Nicolas; Tanguy, Bernard

2010-04-01

Laser imaging offers potential for observation, for 3D terrain-mapping and classification as well as for target identification, including behind vegetation, camouflage or glass windows, at day and night, and under all-weather conditions. First generation systems deliver 3D point clouds. The threshold detection is largely affected by the local opto-geometric characteristics of the objects, leading to inaccuracies in the distances measured, and by partial occultation, leading to multiple echos. Second generation systems circumvent these limitations by recording the temporal waveforms received by the system, so that data processing can improve the telemetry and the point cloud better match the reality. Future algorithms may exploit the full potential of the 4D full-waveform data. Hence, being able to simulate point-cloud (3D) and full-waveform (4D) laser imaging is key. We have developped a numerical model for predicting the output data of 3D or 4D laser imagers. The model does account for the temporal and transverse characteristics of the laser pulse (i.e. of the "laser bullet") emitted by the system, its propagation through turbulent and scattering atmosphere, its interaction with the objects present in the field of view, and the characteristics of the optoelectronic reception path of the system.

A handheld laser-induced fluorescence detector for multiple applications.

PubMed

Fang, Xiao-Xia; Li, Han-Yang; Fang, Pan; Pan, Jian-Zhang; Fang, Qun

2016-04-01

In this paper, we present a compact handheld laser-induced fluorescence (LIF) detector based on a 450 nm laser diode and quasi-confocal optical configuration with a total size of 9.1 × 6.2 × 4.1 cm(3). Since there are few reports on the use of 450 nm laser diode in LIF detection, especially in miniaturized LIF detector, we systematically investigated various optical arrangements suitable for the requirements of 450 nm laser diode and system miniaturization, including focusing lens, filter combination, and pinhole, as well as Raman effect of water at 450 nm excitation wavelength. As the result, the handheld LIF detector integrates the light source (450 nm laser diode), optical circuit module (including a 450 nm band-pass filter, a dichroic mirror, a collimating lens, a 525 nm band-pass filter, and a 1.0mm aperture), optical detector (miniaturized photomultiplier tube), as well as electronic module (including signal recording, processing and displaying units). This detector is capable of working independently with a cost of ca. $2000 for the whole instrument. The detection limit of the instrument for sodium fluorescein solution is 0.42 nM (S/N=3). The broad applicability of the present system was demonstrated in capillary electrophoresis separation of fluorescein isothiocyanate (FITC) labeled amino acids and in flow cytometry of tumor cells as an on-line LIF detector, as well as in droplet array chip analysis as a LIF scanner. We expect such a compact LIF detector could be applied in flow analysis systems as an on-line detector, and in field analysis and biosensor analysis as a portable universal LIF detector. Copyright © 2015 Elsevier B.V. All rights reserved.

Laser applications in surgery

PubMed Central

Azadgoli, Beina

2016-01-01

In modern medicine, lasers are increasingly utilized for treatment of a variety of pathologies as interest in less invasive treatment modalities intensifies. The physics behind lasers allows the same basic principles to be applied to a multitude of tissue types using slight modifications of the system. Multiple laser systems have been studied within each field of medicine. The term “laser” was combined with “surgery,” “ablation,” “lithotripsy,” “cancer treatment,” “tumor ablation,” “dermatology,” “skin rejuvenation,” “lipolysis,” “cardiology,” “atrial fibrillation (AF),” and “epilepsy” during separate searches in the PubMed database. Original articles that studied the application of laser energy for these conditions were reviewed and included. A review of laser therapy is presented. Laser energy can be safely and effectively used for lithotripsy, for the treatment of various types of cancer, for a multitude of cosmetic and reconstructive procedures, and for the ablation of abnormal conductive pathways. For each of these conditions, management with lasers is comparable to, and potentially superior to, management with more traditional methods. PMID:28090508

Low jitter RF distribution system

DOEpatents

Wilcox, Russell; Doolittle, Lawrence; Huang, Gang

2012-09-18

A timing signal distribution system includes an optical frequency stabilized laser signal amplitude modulated at an rf frequency. A transmitter box transmits a first portion of the laser signal and receive a modified optical signal, and outputs a second portion of the laser signal and a portion of the modified optical signal. A first optical fiber carries the first laser signal portion and the modified optical signal, and a second optical fiber carries the second portion of the laser signal and the returned modified optical signal. A receiver box receives the first laser signal portion, shifts the frequency of the first laser signal portion outputs the modified optical signal, and outputs an electrical signal on the basis of the laser signal. A detector at the end of the second optical fiber outputs a signal based on the modified optical signal. An optical delay sensing circuit outputs a data signal based on the detected modified optical signal. An rf phase detect and correct signal circuit outputs a signal corresponding to a phase stabilized rf signal based on the data signal and the frequency received from the receiver box.

A review of the development of optical countermeasures

NASA Astrophysics Data System (ADS)

Titterton, David H.

2004-12-01

Optical countermeasures have been used for several millenia to provide a defensive capability capability. The fundamental approach is to use an intense optical source to dazzle a sensor or distract an operator or target tracking system causing a weapon to miss its intended target. The development of the laser has provided a stimulus for anumber of soft-kill weapon systems used to enhance platform survivability and anti-air missile applications; in this case the laser may cause dazzle, or if the beam is sufficiently intense it may cause damage. Laser technology is also crucial for an aspect of directed energy weapons. The various aspects of optical countermeasures are considered in this paper, including defeat mechanisms of active and passive techniques. The review includes a historical perspective through to prospects for the future.

Progress in coherent laser radar

NASA Technical Reports Server (NTRS)

Vaughan, J. M.

1986-01-01

Considerable progress with coherent laser radar has been made over the last few years, most notably perhaps in the available range of high performance devices and components and the confidence with which systems may now be taken into the field for prolonged periods of operation. Some of this increasing maturity was evident at the 3rd Topical Meeting on Coherent Laser Radar: Technology and Applications. Topics included in discussions were: mesoscale wind fields, nocturnal valley drainage and clear air down bursts; airborne Doppler lidar studies and comparison of ground and airborne wind measurement; wind measurement over the sea for comparison with satellite borne microwave sensors; transport of wake vortices at airfield; coherent DIAL methods; a newly assembled Nd-YAG coherent lidar system; backscatter profiles in the atmosphere and wavelength dependence over the 9 to 11 micrometer region; beam propagation; rock and soil classification with an airborne 4-laser system; technology of a global wind profiling system; target calibration; ranging and imaging with coherent pulsed and CW system; signal fluctuations and speckle. Some of these activities are briefly reviewed.

Measurement of laser power for photo-triggered drug delivery in vivo

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, R.; Zhang, X. L.; Liu, F.

Thus far, despite many investigations have been carried out for photo-triggered drug delivery systems, most of them suffer from an intrinsic drawback of without real-time monitoring mechanism. Incident intensity of light is a feasible parameter to monitor the drug release profiles. However, it is difficult to measure the incident laser power irradiated onto the photo-triggered carriers in drug delivery systems during in vivo therapy. We design an online measurement method based on the fluorescence intensity ratio (FIR) technique through upconversion nanoparticles. FIR value varies with temperature of sample due to the thermal effect induced by the incident laser, which validatesmore » the laser power measurement. Effects of rare earth doping concentration, as well as experimental conditions including laser spots and wavelengths on the measurement behavior were also investigated.« less

Apparatus for controlling the scan width of a scanning laser beam

DOEpatents

Johnson, Gary W.

1996-01-01

Swept-wavelength lasers are often used in absorption spectroscopy applications. In experiments where high accuracy is required, it is desirable to continuously monitor and control the range of wavelengths scanned (the scan width). A system has been demonstrated whereby the scan width of a swept ring-dye laser, or semiconductor diode laser, can be measured and controlled in real-time with a resolution better than 0.1%. Scan linearity, or conformity to a nonlinear scan waveform, can be measured and controlled. The system of the invention consists of a Fabry-Perot interferometer, three CAMAC interface modules, and a microcomputer running a simple analysis and proportional-integral control algorithm. With additional modules, multiple lasers can be simultaneously controlled. The invention also includes an embodiment implemented on an ordinary PC with a multifunction plug-in board.

Apparatus for controlling the scan width of a scanning laser beam

DOEpatents

Johnson, G.W.

1996-10-22

Swept-wavelength lasers are often used in absorption spectroscopy applications. In experiments where high accuracy is required, it is desirable to continuously monitor and control the range of wavelengths scanned (the scan width). A system has been demonstrated whereby the scan width of a swept ring-dye laser, or semiconductor diode laser, can be measured and controlled in real-time with a resolution better than 0.1%. Scan linearity, or conformity to a nonlinear scan waveform, can be measured and controlled. The system of the invention consists of a Fabry-Perot interferometer, three CAMAC interface modules, and a microcomputer running a simple analysis and proportional-integral control algorithm. With additional modules, multiple lasers can be simultaneously controlled. The invention also includes an embodiment implemented on an ordinary PC with a multifunction plug-in board. 8 figs.

Comparison of 2 wavefront-guided excimer lasers for myopic laser in situ keratomileusis: one-year results.

PubMed

Yu, Charles Q; Manche, Edward E

2014-03-01

To compare laser in situ keratomileusis (LASIK) outcomes between 2 wavefront-guided excimer laser systems in the treatment of myopia. University eye clinic, Palo Alto, California, USA. Prospective comparative case series. One eye of patients was treated with the Allegretto Wave Eye-Q system (small-spot scanning laser) and the fellow eye with the Visx Star Customvue S4 IR system (variable-spot scanning laser). Evaluations included measurement of uncorrected visual acuity, corrected visual acuity, and wavefront aberrometry. One hundred eyes (50 patients) were treated. The mean preoperative spherical equivalent (SE) refraction was -3.89 diopters (D) ± 1.67 (SD) and -4.18 ± 1.73 D in the small-spot scanning laser group and variable-spot scanning laser group, respectively. There were no significant differences in preoperative higher-order aberrations (HOAs) between the groups. Twelve months postoperatively, all eyes in the small-spot scanning laser group and 92% in the variable-spot scanning laser group were within ±0.50 D of the intended correction (P = .04). At that time, the small-spot scanning laser group had significantly less spherical aberration (0.12 versus 0.15) (P = .04) and significantly less mean total higher-order root mean square (0.33 μm versus 0.40 μm) (P = .01). Subjectively, patients reported that the clarity of night and day vision was significantly better in the eye treated with the small-spot scanning laser. The predictability and self-reported clarity of vision of wavefront-guided LASIK were better with the small-spot scanning laser. Eyes treated with the small-spot scanning laser had significantly fewer HOAs. Copyright © 2014 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

Laser Threat Analysis System (LTAS)

NASA Astrophysics Data System (ADS)

Pfaltz, John M.; Richardson, Christina E.; Ruiz, Abel; Barsalou, Norman; Thomas, Robert J.

2002-11-01

LTAS is a totally integrated modeling and simulation environment designed for the purpose of ascertaining the susceptibility of Air Force pilots and air crews to optical radiation threats. Using LTAS, mission planners can assess the operational impact of optically directed energy weapons and countermeasures. Through various scenarios, threat analysts are able to determine the capability of laser threats and their impact on operational missions including the air crew's ability to complete their mission effectively. Additionally, LTAS allows the risk of laser use on training ranges and the requirement for laser protection to be evaluated. LTAS gives mission planners and threat analysts complete control of the threat environment including threat parameter control and placement, terrain mapping (line-of-site), atmospheric conditions, and laser eye protection (LEP) selection. This report summarizes the design of the final version of LTAS, and the modeling methodologies implemented to accomplish analysis.

Sensor fusion of cameras and a laser for city-scale 3D reconstruction.

PubMed

Bok, Yunsu; Choi, Dong-Geol; Kweon, In So

2014-11-04

This paper presents a sensor fusion system of cameras and a 2D laser sensorfor large-scale 3D reconstruction. The proposed system is designed to capture data on afast-moving ground vehicle. The system consists of six cameras and one 2D laser sensor,and they are synchronized by a hardware trigger. Reconstruction of 3D structures is doneby estimating frame-by-frame motion and accumulating vertical laser scans, as in previousworks. However, our approach does not assume near 2D motion, but estimates free motion(including absolute scale) in 3D space using both laser data and image features. In orderto avoid the degeneration associated with typical three-point algorithms, we present a newalgorithm that selects 3D points from two frames captured by multiple cameras. The problemof error accumulation is solved by loop closing, not by GPS. The experimental resultsshow that the estimated path is successfully overlaid on the satellite images, such that thereconstruction result is very accurate.

Target diagnostics for commissioning the AWE HELEN Laser Facility 100 TW chirped pulse amplification beam

DOE Office of Scientific and Technical Information (OSTI.GOV)

Eagleton, R. T.; Clark, E. L.; Davies, H. M.

2006-10-15

The capability of the HELEN laser at the Atomic Weapons Establishment Aldermaston has been enhanced by the addition of a short-pulse laser beam to augment the twin opposing nanosecond time scale beams. The short-pulse beam utilizes the chirped pulse amplification (CPA) technique and is capable of delivering up to 60 J on target in a 500 fs pulse, around 100 TW, at the fundamental laser wavelength of 1.054 {mu}m. During the commissioning phase a number of diagnostic systems have been fielded, these include: x-ray pinhole imaging of the laser heated spot, charged particle time of flight, thermoluminescent dosimeter array, calibratedmore » radiochromic film, and CR39 nuclear track detector. These diagnostic systems have been used to verify the performance of the CPA beam to achieve a focused intensity of around 10{sup 19} W cm{sup -2} and to underwrite the facility radiological safety system.« less

Effects of surgery, immunization, and laser immunotherapy on a non-immunogenic metastic tumor model

NASA Astrophysics Data System (ADS)

Chen, Wei R.; Huang, Zheng; Andrienko, Kirill; Stefanov, Stefan; Wolf, Roman F.; Liu, Hong

2006-08-01

Traditional local cancer treatment modalities include surgery and radiation, which has the immediate tumor response due to tumor removal or radiation induced cell death. However, such therapeutic approaches usually do not result in eradiation of tumors, particularly when treating metastatic tumors. In fact, local treatment of primary tumors may stimulate the growth and spread of remote metastasis. Commonly used systemic therapies include chemotherapy and immunotherapy, which target the dividing cells or the immune systems. However, in addition to the severe side effects, chemotherapy often suppresses the immune systems, hence lessening the host's ability to fight the disease. Immunotherapy, on the other hand, aims at educating and stimulating immune systems using either general immune enhancements or antigen-oriented specific immune stimulation. However, so far, the traditional immunotherapy has yielded only limited success in treating cancer patients. A different approach is needed. To combine the advantages of both local therapies for acute and targeted treatment responses and the systemic therapies for stimulation of the immune systems, laser immunotherapy was proposed to use selective photothermal therapy as the local treatment modality and the adjuvant-assisted immunotherapy for systemic control. Laser immunotherapy has show positive results in treating metastatic tumors. In this study, we conducted a comparative study using surgery, freeze-thaw immunization and laser immunotherapy in the treatment of metastatic rat mammary tumors. Our results showed that removal of the primary tumors was unsuccessful at changing the course of tumor progression. The tumor cell lysate immunization delayed the emergence of metastases but did not provide immunity against the tumor challenge. Laser immunotherapy, on the other hand, resulted in regression and eradication.

Galvanometer scanning technology for laser additive manufacturing

NASA Astrophysics Data System (ADS)

Luo, Xi; Li, Jin; Lucas, Mark

2017-02-01

A galvanometer laser beam scanning system is an essential element in many laser additive manufacturing (LAM) technologies including Stereolithography (SLA), Selective Laser Sintering (SLS) and Selective Laser Melting (SLM). Understanding the laser beam scanning techniques and recent innovations in this field will greatly benefit the 3D laser printing system integration and technology advance. One of the challenges to achieve high quality 3D printed parts is due to the non-uniform laser power density delivered on the materials caused by the acceleration and deceleration movements of the galvanometer at ends of the hatching and outlining patterns. One way to solve this problem is to modulate the laser power as the function of the scanning speed during the acceleration or deceleration periods. Another strategy is to maintain the constant scanning speed while accurately coordinating the laser on and off operation throughout the job. In this paper, we demonstrate the high speed, high accuracy and low drift digital scanning technology that incorporates both techniques to achieve uniform laser density with minimal additional process development. With the constant scanning speed method, the scanner not only delivers high quality and uniform results, but also a throughput increase of 23% on a typical LAM job, compared to that of the conventional control method that requires galvanometer acceleration and deceleration movements.

Edge technique for measurement of laser frequency shifts including the Doppler shift

NASA Technical Reports Server (NTRS)

Korb, Larry (Inventor)

1991-01-01

A method is disclosed for determining the frequency shift in a laser system by transmitting an outgoing laser beam. An incoming laser beam having a frequency shift is received. A first signal is acquired by transmitting a portion of the incoming laser beam to an energy monitor detector. A second signal is acquired by transmitting a portion of the incoming laser beam through an edge filter to an edge detector, which derives a first normalized signal which is proportional to the transmission of the edge filter at the frequency of the incoming laser beam. A second normalized signal is acquired which is proportional to the transmission of the edge filter at the frequency of the outgoing laser beam. The frequency shift is determined by processing the first and second normalized signals.

Chirped pulse inverse free-electron laser vacuum accelerator

DOEpatents

Hartemann, Frederic V.; Baldis, Hector A.; Landahl, Eric C.

2002-01-01

A chirped pulse inverse free-electron laser (IFEL) vacuum accelerator for high gradient laser acceleration in vacuum. By the use of an ultrashort (femtosecond), ultrahigh intensity chirped laser pulse both the IFEL interaction bandwidth and accelerating gradient are increased, thus yielding large gains in a compact system. In addition, the IFEL resonance condition can be maintained throughout the interaction region by using a chirped drive laser wave. In addition, diffraction can be alleviated by taking advantage of the laser optical bandwidth with negative dispersion focusing optics to produce a chromatic line focus. The combination of these features results in a compact, efficient vacuum laser accelerator which finds many applications including high energy physics, compact table-top laser accelerator for medical imaging and therapy, material science, and basic physics.

Semiconductor optoelectronic devices for free-space optical communications

NASA Technical Reports Server (NTRS)

Katz, J.

1983-01-01

The properties of individual injection lasers are reviewed, and devices of greater complexity are described. These either include or are relevant to monolithic integration configurations of the lasers with their electronic driving circuitry, power combining methods of semiconductor lasers, and electronic methods of steering the radiation patterns of semiconductor lasers and laser arrays. The potential of AlGaAs laser technology for free-space optical communications systems is demonstrated. These solid-state components, which can generate and modulate light, combine the power of a number of sources and perform at least part of the beam pointing functions. Methods are proposed for overcoming the main drawback of semiconductor lasers, that is, their inability to emit the needed amount of optical power in a single-mode operation.

Qualification and Testing of Quantum Cascade Lasers for Harsh Environments

NASA Astrophysics Data System (ADS)

Brauer, C. S.; Myers, T. L.; Cannon, B. D.; Anderson, C. G.; Crowther, B. G.; Hansen, S.

2014-12-01

Quantum cascade lasers (QCLs) offer the potential for the development of novel, laser-based instruments for both terrestrial and space applications. In order to withstand harsh conditions encountered in these environments, lasers must be robust, and rigorous testing is required before new systems can be utilized. A particular concern for space applications is the potential damage to laser performance caused by radiation exposure. While the effects of radiation exposure in diode lasers have been studied extensively, the effect on QCLs, which are fundamentally different from diode lasers, is not well known. We thus present work to quantify the performance of QCLs after exposure to moderate and high levels of radiation from different sources, including protons and gamma rays, to determine the effects of radiation damage.

A hybrid CATV/16-QAM-OFDM visible laser light communication system

NASA Astrophysics Data System (ADS)

Lin, Chun-Yu; Li, Chung-Yi; Lu, Hai-Han; Chen, Chia-Yi; Jhang, Tai-Wei; Ruan, Sheng-Siang; Wu, Kuan-Hung

2014-10-01

A visible laser light communication (VLLC) system employing a vertical cavity surface emitting laser and spatial light modulator with hybrid CATV/16-QAM-OFDM modulating signals over a 5 m free-space link is proposed and demonstrated. With the assistance of a push-pull scheme, low-noise amplifier, and equalizer, good performances of composite second-order and composite triple beat are obtained, accompanied by an acceptable carrier-to-noise ratio performance for a CATV signal, and a low bit error rate value and clear constellation map are achieved for a 16-QAM-OFDM signal. Such a hybrid CATV/16-QAM-OFDM VLLC system would be attractive for providing services including CATV, Internet and telecommunication services.

Dark solitons in laser radiation build-up dynamics.

PubMed

Woodward, R I; Kelleher, E J R

2016-03-01

We reveal the existence of slowly decaying dark solitons in the radiation build-up dynamics of bright pulses in all-normal dispersion mode-locked fiber lasers, numerically modeled in the framework of a generalized nonlinear Schrödinger equation. The evolution of noise perturbations to quasistationary dark solitons is examined, and the significance of background shape and soliton-soliton collisions on the eventual soliton decay is established. We demonstrate the role of a restoring force in extending soliton interactions in conservative systems to include the effects of dissipation, as encountered in laser cavities, and generalize our observations to other nonlinear systems.

Modeling of Adaptive Optics-Based Free-Space Communications Systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wilks, S C; Morris, J R; Brase, J M

2002-08-06

We introduce a wave-optics based simulation code written for air-optic laser communications links, that includes a detailed model of an adaptive optics compensation system. We present the results obtained by this model, where the phase of a communications laser beam is corrected, after it propagates through a turbulent atmosphere. The phase of the received laser beam is measured using a Shack-Hartmann wavefront sensor, and the correction method utilizes a MEMS mirror. Strehl improvement and amount of power coupled to the receiving fiber for both 1 km horizontal and 28 km slant paths are presented.

Naval Research Reviews. Volume XXXIII. Number 2,

DTIC Science & Technology

1981-01-01

and filler metal addition. ratio weld is a characteristic of a keyhole -produced The most distinctive feature of LB welding , weld . T /h III laser Ii...evolved from these radiation for precision operation, such as hole-drill- efforts include a 3kW CO. laser /workstation system ing, trimming, and welding ...asso- Laser Surface Modifications ciated with thick-section welding of naval structure and surface modification for improved corrosion and The high

COMPARISON OF RETINAL PATHOLOGY VISUALIZATION IN MULTISPECTRAL SCANNING LASER IMAGING.

PubMed

Meshi, Amit; Lin, Tiezhu; Dans, Kunny; Chen, Kevin C; Amador, Manuel; Hasenstab, Kyle; Muftuoglu, Ilkay Kilic; Nudleman, Eric; Chao, Daniel; Bartsch, Dirk-Uwe; Freeman, William R

2018-03-16

To compare retinal pathology visualization in multispectral scanning laser ophthalmoscope imaging between the Spectralis and Optos devices. This retrospective cross-sectional study included 42 eyes from 30 patients with age-related macular degeneration (19 eyes), diabetic retinopathy (10 eyes), and epiretinal membrane (13 eyes). All patients underwent retinal imaging with a color fundus camera (broad-spectrum white light), the Spectralis HRA-2 system (3-color monochromatic lasers), and the Optos P200 system (2-color monochromatic lasers). The Optos image was cropped to a similar size as the Spectralis image. Seven masked graders marked retinal pathologies in each image within a 5 × 5 grid that included the macula. The average area with detected retinal pathology in all eyes was larger in the Spectralis images compared with Optos images (32.4% larger, P < 0.0001), mainly because of better visualization of epiretinal membrane and retinal hemorrhage. The average detection rate of age-related macular degeneration and diabetic retinopathy pathologies was similar across the three modalities, whereas epiretinal membrane detection rate was significantly higher in the Spectralis images. Spectralis tricolor multispectral scanning laser ophthalmoscope imaging had higher rate of pathology detection primarily because of better epiretinal membrane and retinal hemorrhage visualization compared with Optos bicolor multispectral scanning laser ophthalmoscope imaging.

Advanced Energy Conversion Technologies and Architectures for Earth and Beyond

NASA Technical Reports Server (NTRS)

Howell, Joe T.; Fikes, John C.; Phillips, Dane J.; Laycock, Rustin L.; ONeill, Mark; Henley, Mark W.; Fork, Richard L.

2006-01-01

Research, development and studies of novel space-based solar power systems, technologies and architectures for Earth and beyond are needed to reduce the cost of clean electrical power for terrestrial use and to provide a stepping stone for providing an abundance of power in space, i.e., manufacturing facilities, tourist facilities, delivery of power between objects in space, and between space and surface sites. The architectures, technologies and systems needed for space to Earth applications may also be used for in-space applications. Advances in key technologies, i.e., power generation, power management and distribution, power beaming and conversion of beamed power are needed to achieve the objectives of both terrestrial and extraterrestrial applications. There is a need to produce "proof-ofconcept" validation of critical WPT technologies for both the near-term, as well as far-term applications. Investments may be harvested in near-term beam safe demonstrations of commercial WPT applications. Receiving sites (users) include ground-based stations for terrestrial electrical power, orbital sites to provide power for satellites and other platforms, future space elevator systems, space vehicle propulsion, and space surface sites. Space surface receiving sites of particular interest include the areas of permanent shadow near the moon s North and South poles, where WPT technologies could enable access to ice and other useful resources for human exploration. This paper discusses work addressing a promising approach to solar power generation and beamed power conversion. The approach is based on a unique high-power solar concentrator array called Stretched Lens Array (SLA) applied to both solar power generation and beamed power conversion. Since both versions (solar and laser) of SLA use many identical components (only the photovoltaic cells need to be different), economies of manufacturing and scale may be realized by using SLA on both ends of the laser power beaming system in a space solar power application. Near-term uses of this SLA-laser-SLA system may include terrestrial and space exploration in near Earth space. Later uses may include beamed power for bases or vehicles on Mars. Strategies for developing energy infrastructures in space which utilize this technology are presented. This dual use system produces electrical energy efficiently from either coherent light, such as from a highly coherent laser, or from conventional solar illumination. This allows, for example, supplementing solar energy with energy provided by highly coherent laser illumination during periods of low solar illumination or no illumination. This reduces the need for batteries and alternate sources of power. The capability of using laser illumination in a lowest order Gaussian laser mode provides means for transmitting power optically with maximum efficiency and precision over the long distances characteristic of space. A preliminary receiving system similar to that described here, has been produced and tested under solar and laser illumination. A summary of results is given.

Phase-sensitive optical coherence tomography-based vibrometry using a highly phase-stable akinetic swept laser source

DOE Office of Scientific and Technical Information (OSTI.GOV)

Applegate, Brian E.; Park, Jesung; Carbajal, Esteban

Phase-sensitive Optical Coherence Tomography (PhOCT) is an emerging tool for in vivo investigation of the vibratory function of the intact middle and inner ear. PhOCT is able to resolve micron scale tissue morphology in three dimensions as well as measure picometer scale motion at each spatial position. Most PhOCT systems to date have relied upon the phase stability offered by spectrometer detection. On the other hand swept laser source based PhOCT offers a number of advantages including balanced detection, long imaging depths, and high imaging speeds. Unfortunately the inherent phase instability of traditional swept laser sources has necessitated complex usermore » developed hardware/software solutions to restore phase sensitivity. Here we present recent results using a prototype swept laser that overcomes these issues. The akinetic swept laser is electronically tuned and precisely controls sweeps without any mechanical movement, which results in high phase stability. We have developed an optical fiber based PhOCT system around the akinetic laser source that had a 1550 nm center wavelength and a sweep rate of 140 kHz. The stability of the system was measured to be 4.4 pm with a calibrated reflector, thus demonstrating near shot noise limited performance. Using this PhOCT system, we have acquired structural and vibratory measurements of the middle ear in a mouse model, post mortem. The quality of the results suggest that the akinetic laser source is a superior laser source for PhOCT with many advantages that greatly reduces the required complexity of the imaging system.« less

Modelling and control for laser based welding processes: modern methods of process control to improve quality of laser-based joining methods

NASA Astrophysics Data System (ADS)

Zäh, Ralf-Kilian; Mosbach, Benedikt; Hollwich, Jan; Faupel, Benedikt

2017-02-01

To ensure the competitiveness of manufacturing companies it is indispensable to optimize their manufacturing processes. Slight variations of process parameters and machine settings have only marginally effects on the product quality. Therefore, the largest possible editing window is required. Such parameters are, for example, the movement of the laser beam across the component for the laser keyhole welding. That`s why it is necessary to keep the formation of welding seams within specified limits. Therefore, the quality of laser welding processes is ensured, by using post-process methods, like ultrasonic inspection, or special in-process methods. These in-process systems only achieve a simple evaluation which shows whether the weld seam is acceptable or not. Furthermore, in-process systems use no feedback for changing the control variables such as speed of the laser or adjustment of laser power. In this paper the research group presents current results of the research field of Online Monitoring, Online Controlling and Model predictive controlling in laser welding processes to increase the product quality. To record the characteristics of the welding process, tested online methods are used during the process. Based on the measurement data, a state space model is ascertained, which includes all the control variables of the system. Depending on simulation tools the model predictive controller (MPC) is designed for the model and integrated into an NI-Real-Time-System.

Methods for multi-material stereolithography

DOEpatents

Wicker, Ryan [El Paso, TX; Medina, Francisco [El Paso, TX; Elkins, Christopher [Redwood City, CA

2011-06-14

Methods and systems of stereolithography for building cost-efficient and time-saving multi-material, multi-functional and multi-colored prototypes, models and devices configured for intermediate washing and curing/drying is disclosed including: laser(s), liquid and/or platform level sensing system(s), controllable optical system(s), moveable platform(s), elevator platform(s), recoating system(s) and at least one polymer retaining receptacle. Multiple polymer retaining receptacles may be arranged in a moveable apparatus, wherein each receptacle is adapted to actively/passively maintain a uniform, desired level of polymer by including a recoating device and a material fill/remove system. The platform is movably accessible to the polymer retaining receptacle(s), elevator mechanism(s) and washing and curing/drying area(s) which may be housed in a shielded enclosure(s). The elevator mechanism is configured to vertically traverse and rotate the platform, thus providing angled building, washing and curing/drying capabilities. A horizontal traversing mechanism may be included to facilitate manufacturing between components of SL cabinet(s) and/or alternative manufacturing technologies.

Advances in detection of diffuse seafloor venting using structured light imaging.

NASA Astrophysics Data System (ADS)

Smart, C.; Roman, C.; Carey, S.

2016-12-01

Systematic, remote detection and high resolution mapping of low temperature diffuse hydrothermal venting is inefficient and not currently tractable using traditional remotely operated vehicle (ROV) mounted sensors. Preliminary results for hydrothermal vent detection using a structured light laser sensor were presented in 2011 and published in 2013 (Smart) with continual advancements occurring in the interim. As the structured light laser passes over active venting, the projected laser line effectively blurs due to the associated turbulence and density anomalies in the vent fluid. The degree laser disturbance is captured by a camera collecting images of the laser line at 20 Hz. Advancements in the detection of the laser and fluid interaction have included extensive normalization of the collected laser data and the implementation of a support vector machine algorithm to develop a classification routine. The image data collected over a hydrothermal vent field is then labeled as seafloor, bacteria or a location of venting. The results can then be correlated with stereo images, bathymetry and backscatter data. This sensor is a component of an ROV mounted imaging suite which also includes stereo cameras and a multibeam sonar system. Originally developed for bathymetric mapping, the structured light laser sensor, and other imaging suite components, are capable of creating visual and bathymetric maps with centimeter level resolution. Surveys are completed in a standard mowing the lawn pattern completing a 30m x 30m survey with centimeter level resolution in under an hour. Resulting co-registered data includes, multibeam and structured light laser bathymetry and backscatter, stereo images and vent detection. This system allows for efficient exploration of areas with diffuse and small point source hydrothermal venting increasing the effectiveness of scientific sampling and observation. Recent vent detection results collected during the 2013-2015 E/V Nautilus seasons will be presented. Smart, C. J. and Roman, C. and Carey, S. N. (2013) Detection of diffuse seafloor venting using structured light imaging, Geochemistry, Geophysics, Geosystems, 14, 4743-4757

Diode laser-induced tissue effects: in vitro tissue model study and in vivo evaluation of wound healing following non-contact application.

PubMed

Havel, Miriam; Betz, Christian S; Leunig, Andreas; Sroka, Ronald

2014-08-01

The basic difference between the various common medical laser systems is the wavelength of the emitted light, leading to altered light-tissue interactions due to the optical parameters of the tissue. This study examines laser induced tissue effects in an in vitro tissue model using 1,470 nm diode laser compared to our standard practice for endonasal applications (940 nm diode laser) under standardised and reproducible conditions. Additionally, in vivo induced tissue effects following non-contact application with focus on mucosal healing were investigated in a controlled intra-individual design in patients treated for hypertrophy of nasal turbinate. A certified diode laser system emitting the light of λ = 1470 nm was evaluated with regards to its tissue effects (ablation, coagulation) in an in vitro setup on porcine liver and turkey muscle tissue model. To achieve comparable macroscopic tissue effects the laser fibres (600 µm core diameter) were fixed to a computer controlled stepper motor and the laser light was applied in a reproducible procedure under constant conditions. For the in vivo evaluation, 20 patients with nasal obstruction due to hyperplasia of inferior nasal turbinates were included in this prospective randomised double-blinded comparative trial. The endoscopic controlled endonasal application of λ = 1470 nm on the one and λ = 940 nm on the other side, both in 'non-contact' mode, was carried out as an outpatient procedure under local anaesthesia. The postoperative wound healing process (mucosal swelling, scab formation, bleeding, infection) was endoscopically documented and assessed by an independent physician. In the experimental setup, the 1,470 nm laser diode system proved to be efficient in inducing tissue effects in non-contact mode with a reduced energy factor of 5-10 for highly perfused liver tissue to 10-20 for muscle tissue as compared to the 940 nm diode laser system. In the in vivo evaluation scab formation following laser surgery as assessed clinically on endonasal endoscopy was significantly reduced on 1,470 nm treated site compared to 940 nm diode laser treated site. Diode laser system (1,470 nm) induces efficient tissue effects compared to 940 nm diode laser system as shown in the tissue model experiment. From the clinical point of view, the healing process following non-contact diode laser application revealed to be improved using 1,470 nm diode laser compared to our standard diode laser practise with 940 nm. © 2014 Wiley Periodicals, Inc.

Synchronization of pulses from mode-locked lasers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Harvey, G.T.

A study of the synchronization of mode-locked lasers is presented. In particular, we investigate the timing of the laser output pulses with respect to the radio frequency (RF) signal driving the mode-locking elements in the laser cavity. Two types of mode-locked lasers are considered: a cw loss-modulated mode-locked argon ion laser; and a q-switched active-passive mode-locked Nd:YAG laser. We develop theoretical models for the treatment of laser pulse synchronization in both types of lasers. Experimental results are presented on a combined laser system that synchronizes pulses from both an argon ion and a Nd:YAG laser by using a common RFmore » signal to drive independent mode-lockers in both laser cavities. Shot to shot jitter as low as 18 ps (RMS) was measured between the output pulses from the two lasers. The theory of pulse synchronization for the cw loss-modulated mode-locked argon ion laser is based on the relationship between the timing of the mode-locked laser pulse (with respect to the peak of the RF signal) and the length of the laser cavity. Experiments on the argon laser include the measurement of the phase shift of the mode-locked pulse as a function of cavity length and intracavity intensity. The theory of synchronization of the active-passive mode-locked Nd:YAG laser is an extension of the pulse selection model of the active-passive laser. Experiments on the active-passive Nd:YAG laser include: measurement of the early noise fluctuations; measurement of the duration of the linear build-up stage (time between laser threshold and saturation of the absorber); measurement of jitter as a function of the mode-locker modulation depth; and measurement of the output pulse phase shift as a function of cavity length.« less

Laser ultrasonic multi-component imaging

DOEpatents

Williams, Thomas K [Federal Way, WA; Telschow, Kenneth [Des Moines, WA

2011-01-25

Techniques for ultrasonic determination of the interfacial relationship of multi-component systems are discussed. In implementations, a laser energy source may be used to excite a multi-component system including a first component and a second component at least in partial contact with the first component. Vibrations resulting from the excitation may be detected for correlation with a resonance pattern indicating if discontinuity exists at the interface of the first and second components.

The CSU Accelerator and FEL Facility

NASA Astrophysics Data System (ADS)

Biedron, Sandra; Milton, Stephen; D'Audney, Alex; Edelen, Jonathan; Einstein, Josh; Harris, John; Hall, Chris; Horovitz, Kahren; Martinez, Jorge; Morin, Auralee; Sipahi, Nihan; Sipahi, Taylan; Williams, Joel

2014-03-01

The Colorado State University (CSU) Accelerator Facility will include a 6-MeV L-Band electron linear accelerator (linac) with a free-electron laser (FEL) system capable of producing Terahertz (THz) radiation, a laser laboratory, a microwave test stand, and a magnetic test stand. The photocathode drive linac will be used in conjunction with a hybrid undulator capable of producing THz radiation. Details of the systems used in CSU Accelerator Facility are discussed.

Low-field MRI of laser polarized noble gas

NASA Technical Reports Server (NTRS)

Tseng, C. H.; Wong, G. P.; Pomeroy, V. R.; Mair, R. W.; Hinton, D. P.; Hoffmann, D.; Stoner, R. E.; Hersman, F. W.; Cory, D. G.; Walsworth, R. L.

1998-01-01

NMR images of laser polarized 3He gas were obtained at 21 G using a simple, homebuilt instrument. At such low fields magnetic resonance imaging (MRI) of thermally polarized samples (e.g., water) is not practical. Low-field noble gas MRI has novel scientific, engineering, and medical applications. Examples include portable systems for diagnosis of lung disease, as well as imaging of voids in porous media and within metallic systems.

Raster graphic helmet-mounted display study

NASA Technical Reports Server (NTRS)

Beamon, William S.; Moran, Susanna I.

1990-01-01

A design of a helmet mounted display system is presented, including a design specification and development plan for the selected design approach. The requirements for the helmet mounted display system and a survey of applicable technologies are presented. Three helmet display concepts are then described which utilize lasers, liquid crystal display's (LCD's), and subminiature cathode ray tubes (CRT's), respectively. The laser approach is further developed in a design specification and a development plan.

Conceptual design and issues of the laser inertial fusion test (LIFT) reactor—targets and chamber systems

NASA Astrophysics Data System (ADS)

Norimatsu, T.; Kozaki, Y.; Shiraga, H.; Fujita, H.; Okano, K.; Members of LIFT Design Team

2017-11-01

We present the conceptual design of an experimental laser fusion plant known as the laser inertial fusion test (LIFT) reactor. The conceptual design aims at technically connecting a single-shot experiment and a commercial power plant. The LIFT reactor is designed on a three-phase scheme, where each phase has specific goals and the dedicated chambers of each phase are driven by the same laser. Technical issues related to the chamber technology including radiation safety to repeat burst mode operation are discussed in this paper.

Next-generation laser for Inertial Confinement Fusion

DOE Office of Scientific and Technical Information (OSTI.GOV)

Marshall, C.D.; Deach, R.J.; Bibeau, C.

1997-09-29

We report on the progress in developing and building the Mercury laser system as the first in a series of a new generation of diode- pumped solid-state Inertial Confinement Fusion (ICF) lasers at Lawrence Livermore National Laboratory (LLNL). Mercury will be the first integrated demonstration of a scalable laser architecture compatible with advanced high energy density (HED) physics applications. Primary performance goals include 10% efficiencies at 10 Hz and a 1-10 ns pulse with 1 omega energies of 100 J and with 2 omega/3 omega frequency conversion.

Design, Qualification, and On Orbit Performance of the CALIPSO Aerosol Lidar Transmitter

NASA Technical Reports Server (NTRS)

Hovis, Floyd E.; Witt, Greg; Sullivan, Edward T.; Le, Khoa; Weimer, Carl; Applegate, Jeff; Luck, William S., Jr.; Verhapen, Ron; Cisewski, Michael S.

2007-01-01

The laser transmitter for the CALIPSO aerosol lidar mission has been operating on orbit as planned since June 2006. This document discusses the optical and laser system design and qualification process that led to this success. Space-qualifiable laser design guidelines included the use of mature laser technologies, the use of alignment sensitive resonator designs, the development and practice of stringent contamination control procedures, the operation of all optical components at appropriately derated levels, and the proper budgeting for the space-qualification of the electronics and software.

Ground-to-space optical power transfer. [using laser propulsion for orbit transfer

NASA Technical Reports Server (NTRS)

Mevers, G. E.; Hayes, C. L.; Soohoo, J. F.; Stubbs, R. M.

1978-01-01

Using laser radiation as the energy input to a rocket, it is possible to consider the transfer of large payloads economically between low initial orbits and higher energy orbits. In this paper we will discuss the results of an investigation to use a ground-based High Energy Laser (HEL) coupled to an adaptive antenna to transmit multi-megawatts of power to a satellite in low-earth orbit. Our investigation included diffraction effects, atmospheric transmission efficiency, adaptive compensation for atmospheric turbulence effects, including the servo bandwidth requirements for this correction, and the adaptive compensation for thermal blooming. For these evaluations we developed vertical profile models of atmospheric absorption, strength of optical turbulence (CN2), wind, temperature, and other parameters necessary to calculate system performance. Our atmospheric investigations were performed for CO2, 12C18O2 isotope, CO and DF wavelengths. For all of these considerations, output antenna locations of both sea level and mountain top (3.5 km above sea level) were used. Several adaptive system concepts were evaluated with a multiple source phased array concept being selected. This system uses an adaption technique of phase locking independent laser oscillators. When both system losses and atmospheric effects were assessed, the results predicted an overall power transfer efficiency of slightly greater than 50%.

The TMT Adaptive Optics Program

NASA Astrophysics Data System (ADS)

Ellerbroek, Brent

2011-09-01

We provide an overview of the Thirty Meter Telescope (TMT) AO program, with an emphasis upon the progress made since the first AO4ELT conference held in 2009. The first light facility AO system for TMT is the Narrow Field Infra-Red AO System (NFIRAOS), which will provide diffraction-limited performance in the J, H, and K bands over 18-30 arc sec diameter fields with 50% sky coverage at the galactic pole. This is accomplished with order 60x60 wavefront sensing and correction, two deformable mirrors conjugate to ranges of 0 and 11.2 km, 6 sodium laser guide stars in an asterism with a diameter of 70 arc sec, and three low order (tip/tilt or tip/tilt focus), infra-red natural guide star (NGS) wavefront sensors deployable within a 2 arc minute diameter patrol field. The first light LGS asterism is generated by the Laser Guide Star Facility (LGSF), which initially incorporates 6 20-25W class laser systems mounted to the telescope elevation journal, a mirror-based beam transfer optics system, and a 0.4m diameter laser launch telescope located behind the TMT secondary mirror. Future plans for additional AO capabilities include a mid infra-red AO (MIRAO) system to support science instruments in the 4-20 micron range, a ground-layer AO (GLAO) system for wide-field spectroscopy, a multi-object AO (MOAO) system for multi-object integral field unit spectroscopy, and extreme AO (ExAO) for high contrast imaging. Significant progress has been made in developing the first-light AO architecture since 2009. This includes the adoption of a new NFIRAOS opto-mechanical design consisting of two off-axis parabola (OAP) relays in series, which eliminates field distortion and also significantly simplifies the designs of the LGS wavefront sensors, optical source simulators, and turbulence generator subsystem. The design of the LGSF has also been interated, and has been simplfied by the relocation of the (smaller, gravity invarient) laser systems to the telescope elevation journal. Protoyping activities continue for laser systems, wavefront sensing detectors, and deformable mirrors; work on the associated detector and deformable mirror electronics has also been initiated. AO Performance estimates and error budgets have been further detailed. Some of the modeling topics which have received particular attention include turbulence (Cn2) profile estimation from LGS WFS measurements, sodium layer range tracking, PSF reconstruction for multi-conjugate AO, LGS fratricide, astrometry at the galactic center, and further optimizing sky coverage and the peformance of the tip/tilt and low-order NGS mode control loops. Finally, experiments and field tests continue at the University of British Columbia LIDAR facility to measure the spatial and temporal variability of the sodium layer, and to characterize the sodium coupling efficiency of candidate laser systems for TMT.

36 Years of Remote Oceanographic Laser Fluorosensing: Findings, Challenges and Pathways to Explore

NASA Astrophysics Data System (ADS)

Chekalyuk, A. M.

2009-12-01

Since its initial bright start in early 70s, the oceanographic applications of laser remote fluorosensing have been mostly driven by the enthusiastic laser geeks, who tried to transfer the recent technological advances from their laboratory breadboards to the real world. This communication provides an overview of the key milestones and advances in the oceanographic applications of remote laser fluorosensing that is used for qualitative and quantitative characterization of the key aquatic constituents, including chromophoric dissolved organic matter, phytoplankton pigments, their biomass, community structure, and photo-physiological status. The basic principles and analytical techniques, including fluorescence excitation and emission measurements, as well as active control over the media to retrieve additional information (“super-active remote sensing”), are briefly discussed and illustrated with examples of practical applications. The laser excitation sources (including solid state, tunable lasers and optical parametric oscillators) and signal detectors and analyzers (including multi-spectral and hyperspectral systems) are discussed. The advantages and limitations of various platforms (stationary settings, ships, airplanes, helicopters, unmanned autonomous vehicles (UAV), and satellites) are analyzed. The recent findings, methodological and technological developments in oceanographic applications of laser fluorescence indicate that there is a significant, still underexplored potential of remote fluorosensing that may provide new observational capabilities and serve as a useful tool for oceanographic research, bio-environmental monitoring, and validation of passive satellite retrievals.

Nanotube Activities at NASA-Johnson Space Center

NASA Technical Reports Server (NTRS)

Arepalli, Sivaram

2004-01-01

Nanotube activities at NASA-Johnson Space Center include production, purification, characterization as well as applications of single wall carbon nanotubes (SWCNTs). A parametric study of the pulsed laser ablation process is recently completed to monitor the effect of production parameters including temperature, buffer gas, flow rate, pressure, and laser fluence. Enhancement of production is achieved by rastering the graphite target and by increasing the target surface temperature with a cw laser. In-situ diagnostics during production included time resolved passive emission and laser induced fluorescence from the plume. The improvement of the purity by a variety of steps in the purification process is monitored by characterization techniques including SEM, TEM, Raman, UV-VIS-NIR and TGA. A recently established NASA-JSC protocol for SWCNT characterization is undergoing revision with feedback from nanotube community. Efforts at JSC over the past five years in composites have centered on structural polymer/nanotube systems. Recent activities broadened this focus to multifunctional materials, supercapacitors, fuel cells, regenerable CO2 absorbers, electromagnetic shielding, radiation dosimetry and thermal management systems of interest for human space flight. Preliminary tests indicate improvement of performance in most of these applications because of the large Surface area as well as high electrical and thermal conductivity exhibited by SWCNTs. Comparison with existing technologies and possible future improvements in the SWCNT materials sill be presented.

A New Patient Record System Using the Laser Card

PubMed Central

Brown, J.H.U.; Vallbona, Carlos

1988-01-01

A method of handling medical data in the form of patient records including physical findings such as x-rays has been devised using a laser card coupled to a p.c. for data input and output. A satisfactory software system which encompasses a formalized medical record system dealing with events rather than chronological order of entry has been devised and is now under test in a community health clinic. Future directions of the card research are discussed and expanded upon. ImagesFig. 7

Study of optical techniques for the Ames unitary wind tunnel: Digital image processing, part 6

NASA Technical Reports Server (NTRS)

Lee, George

1993-01-01

A survey of digital image processing techniques and processing systems for aerodynamic images has been conducted. These images covered many types of flows and were generated by many types of flow diagnostics. These include laser vapor screens, infrared cameras, laser holographic interferometry, Schlieren, and luminescent paints. Some general digital image processing systems, imaging networks, optical sensors, and image computing chips were briefly reviewed. Possible digital imaging network systems for the Ames Unitary Wind Tunnel were explored.

A compact, efficient, and lightweight laser head for CARLO®: integration, performance, and benefits

NASA Astrophysics Data System (ADS)

Deibel, Waldemar; Schneider, Adrian; Augello, Marcello; Bruno, Alfredo E.; Juergens, Philipp; Cattin, Philippe

2015-09-01

Ever since the first functional lasers were built about 50 years ago, researchers and doctors dream of a medical use for such systems. Today's technology is finally advanced enough to realize these ambitions in a variety of medical fields. There are well-established laser based systems in ophthalmology, dental applications, treatment of kidney stones, and many more. Using lasers presents more than just an alternative to conventional methods for osteotomies. It offers less tissue damage, faster healing times, comparable intervention duration and in consequence improves postoperative treatment of patients. However, there are a few factors that limit routine applications. These technical drawbacks include missing depth control and safe guiding of the laser beam. This paper presents the engineering and integration of a miniaturized laser head for a computer assisted and robot-guided laser osteotome (CARLO®), which can overcome the mentioned drawbacks. The CARLO® device ensures a safe and precise guidance of the laser beam. Such guidance also enables new opportunities and methods, e.g. free geometrical functional cuts, which have the potential to revolutionize bone surgery. The laser head is optimized for beam shaping, target conditioning, working distance, compactness and the integration of all other parts needed, e.g. CCD-cameras for monitoring and referencing, a visible laser for cut simulation, etc. The beam coming out of the laser system is conditioned in shape, energy properties and working distance with an optical arrangement to achieve the desired cutting performance. Here also parameters like optical losses, operating mode, optics materials and long-term stability have are taken into account.

Semiconductor Laser Multi-Spectral Sensing and Imaging

PubMed Central

Le, Han Q.; Wang, Yang

2010-01-01

Multi-spectral laser imaging is a technique that can offer a combination of the laser capability of accurate spectral sensing with the desirable features of passive multispectral imaging. The technique can be used for detection, discrimination, and identification of objects by their spectral signature. This article describes and reviews the development and evaluation of semiconductor multi-spectral laser imaging systems. Although the method is certainly not specific to any laser technology, the use of semiconductor lasers is significant with respect to practicality and affordability. More relevantly, semiconductor lasers have their own characteristics; they offer excellent wavelength diversity but usually with modest power. Thus, system design and engineering issues are analyzed for approaches and trade-offs that can make the best use of semiconductor laser capabilities in multispectral imaging. A few systems were developed and the technique was tested and evaluated on a variety of natural and man-made objects. It was shown capable of high spectral resolution imaging which, unlike non-imaging point sensing, allows detecting and discriminating objects of interest even without a priori spectroscopic knowledge of the targets. Examples include material and chemical discrimination. It was also shown capable of dealing with the complexity of interpreting diffuse scattered spectral images and produced results that could otherwise be ambiguous with conventional imaging. Examples with glucose and spectral imaging of drug pills were discussed. Lastly, the technique was shown with conventional laser spectroscopy such as wavelength modulation spectroscopy to image a gas (CO). These results suggest the versatility and power of multi-spectral laser imaging, which can be practical with the use of semiconductor lasers. PMID:22315555

Semiconductor laser multi-spectral sensing and imaging.

PubMed

Le, Han Q; Wang, Yang

2010-01-01

Multi-spectral laser imaging is a technique that can offer a combination of the laser capability of accurate spectral sensing with the desirable features of passive multispectral imaging. The technique can be used for detection, discrimination, and identification of objects by their spectral signature. This article describes and reviews the development and evaluation of semiconductor multi-spectral laser imaging systems. Although the method is certainly not specific to any laser technology, the use of semiconductor lasers is significant with respect to practicality and affordability. More relevantly, semiconductor lasers have their own characteristics; they offer excellent wavelength diversity but usually with modest power. Thus, system design and engineering issues are analyzed for approaches and trade-offs that can make the best use of semiconductor laser capabilities in multispectral imaging. A few systems were developed and the technique was tested and evaluated on a variety of natural and man-made objects. It was shown capable of high spectral resolution imaging which, unlike non-imaging point sensing, allows detecting and discriminating objects of interest even without a priori spectroscopic knowledge of the targets. Examples include material and chemical discrimination. It was also shown capable of dealing with the complexity of interpreting diffuse scattered spectral images and produced results that could otherwise be ambiguous with conventional imaging. Examples with glucose and spectral imaging of drug pills were discussed. Lastly, the technique was shown with conventional laser spectroscopy such as wavelength modulation spectroscopy to image a gas (CO). These results suggest the versatility and power of multi-spectral laser imaging, which can be practical with the use of semiconductor lasers.

Shaping propagation invariant laser beams

NASA Astrophysics Data System (ADS)

Soskind, Michael; Soskind, Rose; Soskind, Yakov

2015-11-01

Propagation-invariant structured laser beams possess several unique properties and play an important role in various photonics applications. The majority of propagation invariant beams are produced in the form of laser modes emanating from stable laser cavities. Therefore, their spatial structure is limited by the intracavity mode formation. We show that several types of anamorphic optical systems (AOSs) can be effectively employed to shape laser beams into a variety of propagation invariant structured fields with different shapes and phase distributions. We present a propagation matrix approach for designing AOSs and defining mode-matching conditions required for preserving propagation invariance of the output shaped fields. The propagation matrix approach was selected, as it provides a more straightforward approach in designing AOSs for shaping propagation-invariant laser beams than the alternative technique based on the Gouy phase evolution, especially in the case of multielement AOSs. Several practical configurations of optical systems that are suitable for shaping input laser beams into a diverse variety of structured propagation invariant laser beams are also presented. The laser beam shaping approach was applied by modeling propagation characteristics of several input laser beam types, including Hermite-Gaussian, Laguerre-Gaussian, and Ince-Gaussian structured field distributions. The influence of the Ince-Gaussian beam semifocal separation parameter and the azimuthal orientation between the input laser beams and the AOSs onto the resulting shape of the propagation invariant laser beams is presented as well.

Detection system of capillary array electrophoresis microchip based on optical fiber

NASA Astrophysics Data System (ADS)

Yang, Xiaobo; Bai, Haiming; Yan, Weiping

2009-11-01

To meet the demands of the post-genomic era study and the large parallel detections of epidemic diseases and drug screening, the high throughput micro-fluidic detection system is needed urgently. A scanning laser induced fluorescence detection system based on optical fiber has been established by using a green laser diode double-pumped solid-state laser as excitation source. It includes laser induced fluorescence detection subsystem, capillary array electrophoresis micro-chip, channel identification unit and fluorescent signal processing subsystem. V-shaped detecting probe composed with two optical fibers for transmitting the excitation light and detecting induced fluorescence were constructed. Parallel four-channel signal analysis of capillary electrophoresis was performed on this system by using Rhodamine B as the sample. The distinction of different samples and separation of samples were achieved with the constructed detection system. The lowest detected concentration is 1×10-5 mol/L for Rhodamine B. The results show that the detection system possesses some advantages, such as compact structure, better stability and higher sensitivity, which are beneficial to the development of microminiaturization and integration of capillary array electrophoresis chip.

Study on the effect of beam propagation through atmospheric turbulence on standoff nanosecond laser induced breakdown spectroscopy measurements.

PubMed

Laserna, J J; Reyes, R Fernández; González, R; Tobaria, L; Lucena, P

2009-06-08

We report on an experimental study of the effect of atmospheric turbulence on laser induced breakdown spectroscopy (LIBS) measurements. The characteristics of the atmosphere dictate specific performance constraints to this technology. Unlike classical laboratory LIBS systems where the distance to the sample is well known and characterized, LIBS systems working at several tens of meters to the target have specific atmospheric propagation conditions that cause the quality of the LIBS signals to be affected to a significant extent. Using a new LIBS based sensor system fitted with a nanosecond laser emitting at 1064 nm, propagation effects at distances of up to 120 m were investigated. The effects observed include wander and scintillation in the outgoing laser beam and in the return atomic emission signal. Plasmas were formed on aluminium targets. Average signal levels and signal fluctuations are measured so the effect of atmospheric turbulence on LIBS measurements is quantified.

Soliton microcomb range measurement.

PubMed

Suh, Myoung-Gyun; Vahala, Kerry J

2018-02-23

Laser-based range measurement systems are important in many application areas, including autonomous vehicles, robotics, manufacturing, formation flying of satellites, and basic science. Coherent laser ranging systems using dual-frequency combs provide an unprecedented combination of long range, high precision, and fast update rate. We report dual-comb distance measurement using chip-based soliton microcombs. A single pump laser was used to generate dual-frequency combs within a single microresonator as counterpropagating solitons. We demonstrated time-of-flight measurement with 200-nanometer precision at an averaging time of 500 milliseconds within a range ambiguity of 16 millimeters. Measurements at distances up to 25 meters with much lower precision were also performed. Our chip-based source is an important step toward miniature dual-comb laser ranging systems that are suitable for photonic integration. Copyright © 2018 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.

In situ industrial applications of optics; Proceedings of the Meeting, Brussels, Belgium, June 25-27, 1986

NASA Astrophysics Data System (ADS)

Ebbeni, Jean

Included in this volume are papers on real-time image enhancement by simple video systems, automatic identification and data collection via barcode laser scanning, the optimization of the cutting up of a strip of float glass, optical sensors for factory automation, and the use of a digital theodolite with infrared radiation. Attention is also given to ISIS (integrated shape imaging system), a new system for follow-up of scoliosis; optical diffraction extensometers; a cross-spectrum technique for high-sensitivity remote vibration analysis by optical interferometry; the compensation and measurement of any motion of three-dimensional objects in holographic interferometry; and stereoscreen. Additional papers are on holographic double pulse YAG lasers, miniature optic connectors, stress-field analysis in an adhesively bonded joint with laser photoelasticimetry, and the locking of the light pulse delay in externally triggered gas lasers.

High-power lasers for directed-energy applications.

PubMed

Sprangle, Phillip; Hafizi, Bahman; Ting, Antonio; Fischer, Richard

2015-11-01

In this article, we review and discuss the research programs at the Naval Research Laboratory (NRL) on high-power lasers for directed-energy (DE) applications in the atmosphere. Physical processes affecting propagation include absorption/scattering, turbulence, and thermal blooming. The power levels needed for DE applications require combining a number of lasers. In atmospheric turbulence, there is a maximum intensity that can be placed on a target that is independent of the initial beam spot size and laser beam quality. By combining a number of kW-class fiber lasers, scientists at the NRL have successfully demonstrated high-power laser propagation in a turbulent atmosphere and wireless recharging. In the NRL experiments, four incoherently combined fiber lasers having a total power of 5 kW were propagated to a target 3.2 km away. These successful high-power experiments in a realistic atmosphere formed the basis of the Navy's Laser Weapon System. We compare the propagation characteristics of coherently and incoherently combined beams without adaptive optics. There is little difference in the energy on target between coherently and incoherently combined laser beams for multi-km propagation ranges and moderate to high levels of turbulence. Unlike incoherent combining, coherent combining places severe constraints on the individual lasers. These include the requirement of narrow power spectral linewidths in order to have long coherence times as well as polarization alignment of all the lasers. These requirements are extremely difficult for high-power lasers.

An experimental investigation of 235 sub UF sub 6 fission produced plasmas. [gas handling system for use with nuclear pumped laser experiments

NASA Technical Reports Server (NTRS)

Miley, G. H.

1981-01-01

A gas handling system capable of use with uranium fluoride was designed and constructed for use with nuclear pumped laser experiments using the TRIGA research reactor. By employing careful design and temperature controls, the UF6 can be first transported into the irradiation chamber, and then, at the conclusion of the experiment, returned to gas cylinders. The design of the system is described. Operating procedures for the UF6 and gas handling systems are included.

Laser Microdissection and Atmospheric Pressure Chemical Ionization Mass Spectrometry Coupled for Multimodal Imaging

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lorenz, Matthias; Ovchinnikova, Olga S; Kertesz, Vilmos

2013-01-01

This paper describes the coupling of ambient laser ablation surface sampling, accomplished using a laser capture microdissection system, with atmospheric pressure chemical ionization mass spectrometry for high spatial resolution multimodal imaging. A commercial laser capture microdissection system was placed in close proximity to a modified ion source of a mass spectrometer designed to allow for sampling of laser ablated material via a transfer tube directly into the ionization region. Rhodamine 6G dye of red sharpie ink in a laser etched pattern as well as cholesterol and phosphatidylcholine in a cerebellum mouse brain thin tissue section were identified and imaged frommore » full scan mass spectra. A minimal spot diameter of 8 m was achieved using the 10X microscope cutting objective with a lateral oversampling pixel resolution of about 3.7 m. Distinguishing between features approximately 13 m apart in a cerebellum mouse brain thin tissue section was demonstrated in a multimodal fashion including co-registered optical and mass spectral chemical images.« less

Reflex ring laser amplifier system

DOEpatents

Summers, M.A.

1983-08-31

The invention is a method and apparatus for providing a reflex ring laser system for amplifying an input laser pulse. The invention is particularly useful in laser fusion experiments where efficient production of high-energy and high power laser pulses is required. The invention comprises a large aperture laser amplifier in an unstable ring resonator which includes a combination spatial filter and beam expander having a magnification greater than unity. An input pulse is injected into the resonator, e.g., through an aperture in an input mirror. The injected pulse passes through the amplifier and spatial filter/expander components on each pass around the ring. The unstable resonator is designed to permit only a predetermined number of passes before the amplified pulse exits the resonator. On the first pass through the amplifier, the beam fills only a small central region of the gain medium. On each successive pass, the beam has been expanded to fill the next concentric non-overlapping region of the gain medium.

Measuring the Refractive Index of a Laser-Plasma Optical System

NASA Astrophysics Data System (ADS)

Turnbull, D.; Goyon, C.; Pollock, B. B.; Mariscal, D.; Divol, L.; Ross, J. S.; Patankar, S.; Kemp, G. E.; Moody, J. D.; Michel, P. A.

2016-10-01

We report the first complete set of measurements of a laser-plasma optical system's refractive index, as seen by an independent probe laser beam, as a function of the relative wavelength shift between the two laser beams. Both the imaginary and real refractive-index components are found to be in good agreement with linear theory using plasma parameters measured by optical Thomson scattering and interferometry; the former is in contrast to previous work and has implications for cross-beam energy transfer in indirect-drive inertial confinement fusion, and the latter is measured for the first time. The data include the first demonstration of a laser-plasma polarizer with 85% to 87% extinction for the particular laser and plasma parameters used in this experiment, complementing the existing suite of high-power, tunable, and ultrafast plasma-based photonic devices. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

Method and apparatus for determining the physical properties of materials using dynamic light scattering techniques

NASA Technical Reports Server (NTRS)

Dhadwal, Harbans S. (Inventor)

1992-01-01

A system for determining the physical properties of materials through the use of dynamic light scattering is disclosed. The system includes a probe, a laser source for directing a laser beam into the probe, and a photodetector for converting scattered light detected by the probe into electrical signals. The probe includes at least one optical fiber connected to the laser source and a second optical fiber connected to the photodetector. Each of the fibers may adjoin a gradient index microlens which is capable of providing a collimated laser beam into a scattering medium. The position of the second optical fiber with respect to the optical axis of the probe determines whether homodyne or self-beating detection is provided. Self-beating detection may be provided without a gradient index microlens. This allows a very small probe to be constructed which is insertable through a hypodermic needle or the like into a droplet extending from such a needle. A method of detecting scattered light through the use of a collimated, Gaussian laser beam is also provided. A method for controlling the waist and divergence of the optical field emanating from the free end of an optical fiber is also provided.

The effect of optical system design for laser micro-hole drilling process

NASA Astrophysics Data System (ADS)

Ding, Chien-Fang; Lan, Yin-Te; Chien, Yu-Lun; Young, Hong-Tsu

2017-08-01

Lasers are a promising high accuracy tool to make small holes in composite or hard material. They offer advantages over the conventional machining process, which is time consuming and has scaling limitations. However, the major downfall in laser material processing is the relatively large heat affect zone or number of molten burrs it generates, even when using nanosecond lasers over high-cost ultrafast lasers. In this paper, we constructed a nanosecond laser processing system with a 532 nm wavelength laser source. In order to enhance precision and minimize the effect of heat generation with the laser drilling process, we investigated the geometric shape of optical elements and analyzed the images using the modulation transfer function (MTF) and encircled energy (EE) by using optical software Zemax. We discuss commercial spherical lenses, including plano-convex lenses, bi-convex lenses, plano-concave lenses, bi-concave lenses, best-form lenses, and meniscus lenses. Furthermore, we determined the best lens configuration by image evaluation, and then verified the results experimentally by carrying out the laser drilling process on multilayer flexible copper clad laminate (FCCL). The paper presents the drilling results obtained with different lens configurations and found the best configuration had a small heat affect zone and a clean edge along laser-drilled holes.

Laser hazards and safety in the military environment. Lecture series

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

The Lecture Series is intended to provide an understanding of the safety problems associated with the military use of lasers. The most important hazard is the inadvertent irradiation of the eye and so the series will include contributions from the physical and biological sciences, as well as from ophthalmologists. Those involved with laser safety come from many backgrounds -- from physics to engineering and from vision physiology to clinical ophthalmology and it is essential that each understands the contribution of the other. The lectures include an introductory part and from this, the more advanced aspects of each subject are covered,more » leading to the issues involved in the design of safety codes and the control of laser hazards. The final session deals with medical surveillance of laser personnel. The Series is of value to both military and civilian personnel involved with safety, whether they are concerned with land, sea or airborne laser systems. (GRA)« less

Combined pulsed dye and CO2 lasers in the treatment of angiolymphoid hyperplasia with eosinophilia.

PubMed

Sagi, Lior; Halachmi, Shlomit; Levi, Assi; Amitai, Dan Ben; Enk, Claes D; Lapidoth, Moshe

2016-08-01

Angiolymphoid hyperplasia with eosinophilia (ALHE) is an uncommon dermatosis of unknown etiology that manifests as characteristic red nodules and papules with a predilection for the scalp and periauricular region. Treatment is required for both esthetic and functional reasons, as lesions may ulcerate and bleed. Many treatment approaches have been reported, including excision, systemic medical approaches, topical or intralesional therapies, and non-invasive modalities including cryotherapy, electrosurgery, and laser. Treatments have exhibited variable efficacy, and the recurrence rate is 100 %. We report the combination of pulsed dye laser and CO2 laser in the treatment of ALHE in 14 patients. All patients exhibited clinical response after a mean of 2.4 ± 0.4 treatment sessions. The clinical efficacy of the combined treatment, together with its well-tolerated nature, render the use of pulsed dye laser in combination with CO2 laser, a viable treatment for debulking ALHE lesions. Ongoing maintenance treatments are needed to due to the high degree of relapse.

Mode Tracker for Mode-Hop-Free Operation of a Laser

NASA Technical Reports Server (NTRS)

Wysocki, Gerard; Tittel, Frank K.; Curl, Robert F.

2010-01-01

A mode-tracking system that includes a mode-controlling subsystem has been incorporated into an external-cavity (EC) quantum cascade laser that operates in a mid-infrared wavelength range. The mode-tracking system makes it possible to perform mode-hop-free wavelength scans, as needed for high-resolution spectroscopy and detection of trace gases. The laser includes a gain chip, a beam-collimating lens, and a diffraction grating. The grating is mounted on a platform, the position of which can be varied to effect independent control of the EC length and the grating angle. The position actuators include a piezoelectric stage for translation control and a motorized stage for coarse rotation control equipped with a piezoelectric actuator for fine rotation control. Together, these actuators enable control of the EC length over a range of about 90 m with a resolution of 0.9 nm, and control of the grating angle over a coarse-tuning range of +/-6.3deg and a fine-tuning range of +/-520 microrad with a resolution of 10 nrad. A mirror mounted on the platform with the grating assures always the same direction of the output laser beam.

What's New for Laser Orbital Debris Removal

NASA Astrophysics Data System (ADS)

Phipps, Claude; Lander, Mike

2011-11-01

Orbital debris in low Earth orbit (LEO) are now sufficiently dense that the use of space is threatened by runaway collision cascading. A problem predicted more than thirty years ago, the threat from debris larger than about 1cm is now a reality that we ignore at our peril. The least costly, and most comprehensive, solution is Laser Orbital Debris Removal (LODR). In this approach, a high power pulsed laser on the Earth creates a laser-ablation jet on the debris object's surface which provides the small impulse required to cause it to re-enter and burn up in the atmosphere. The LODR system should be located near the Equator, and includes the laser, a large, agile mirror, and systems for active detection, tracking and atmospheric path correction. In this paper, we discuss advances that have occurred since LODR was first proposed, which make this solution to the debris problem look quite realistic.

The BAPE 2 balloon-borne CO2

NASA Technical Reports Server (NTRS)

Degnan, J. J.; Walker, H. E.; Peruso, C. J.; Johnson, E. H.; Klein, B. J.; Mcelroy, J. H.

1972-01-01

The systems and techniques which were utilized in the experiment to establish an air-to-ground CO2 laser heterodyne link are described along with the successes and problems encountered when the heterodyne receiver and laser transmitter package were removed from the controlled environment of the laboratory. Major topics discussed include: existing systems and the underlying principles involved in their operation; experimental techniques and optical alignment methods which were found to be useful; theoretical calculations of signal strengths expected under a variety of test conditions and in actual flight; and the experimental results including problems encountered and their possible solutions.

Arbitrary temporal shape pulsed fiber laser based on SPGD algorithm

NASA Astrophysics Data System (ADS)

Jiang, Min; Su, Rongtao; Zhang, Pengfei; Zhou, Pu

2018-06-01

A novel adaptive pulse shaping method for a pulsed master oscillator power amplifier fiber laser to deliver an arbitrary pulse shape is demonstrated. Numerical simulation has been performed to validate the feasibility of the scheme and provide meaningful guidance for the design of the algorithm control parameters. In the proof-of-concept experiment, information on the temporal property of the laser is exchanged and evaluated through a local area network, and the laser adjusted the parameters of the seed laser according to the monitored output of the system automatically. Various pulse shapes, including a rectangular shape, ‘M’ shape, and elliptical shape are achieved through experimental iterations.

Laser Powered Launch Vehicle Performance Analyses

NASA Technical Reports Server (NTRS)

Chen, Yen-Sen; Liu, Jiwen; Wang, Ten-See (Technical Monitor)

2001-01-01

The purpose of this study is to establish the technical ground for modeling the physics of laser powered pulse detonation phenomenon. Laser powered propulsion systems involve complex fluid dynamics, thermodynamics and radiative transfer processes. Successful predictions of the performance of laser powered launch vehicle concepts depend on the sophisticate models that reflects the underlying flow physics including the laser ray tracing the focusing, inverse Bremsstrahlung (IB) effects, finite-rate air chemistry, thermal non-equilibrium, plasma radiation and detonation wave propagation, etc. The proposed work will extend the base-line numerical model to an efficient design analysis tool. The proposed model is suitable for 3-D analysis using parallel computing methods.

Frequency locking of compact laser-diode modules at 633 nm

NASA Astrophysics Data System (ADS)

Nölleke, Christian; Leisching, Patrick; Blume, Gunnar; Jedrzejczyk, Daniel; Pohl, Johannes; Feise, David; Sahm, Alexander; Paschke, Katrin

2018-02-01

This work reports on a compact diode-laser module emitting at 633 nm. The emission frequency can be tuned with temperature and current, while optical feedback of an internal DBR grating ensures single-mode operation. The laser diode is integrated into a micro-fabricated package, which includes optics for beam shaping, a miniaturized optical isolator, and a vapor cell as frequency reference. The achieved absolute frequency stability is below 10-8 , while the output power can be more than 10 mW. This compact absolute frequency-stabilized laser system can replace gas lasers and may be integrated in future quantum technology devices.

Using Stars to Align a Steered Laser System for Cosmic Ray Simulation

NASA Astrophysics Data System (ADS)

Krantz, Harry; Wiencke, Lawrence

2016-03-01

Ultra high energy cosmic rays (UHECRs) are the highest energy cosmic particles with kinetic energy above 1018eV . UHECRs are detected from the air shower of secondary particles and UV florescence that results from interaction with the atmosphere. A high power UV laser beam can be used to simulate the optical signature of a UHCER air shower. The Global Light System (GLS) is a planned network of ground-based light sources including lasers to support the planned space-based Extreme Universe Space Observatory (EUSO). A portable prototype GLS laser station has been constructed at the Colorado School of Mines. Currently the laser system uses reference targets on the ground but stars can be used to better align the beam by providing a complete hemisphere of targets. In this work, a CCD camera is used to capture images of known stars through the steering head optics. The images are analyzed to find the steering head coordinates of the target star. The true coordinates of the star are calculated from the location and time of observation. A universal adjustment for the steering head is determined from the differences between the two pairs of coordinates across multiple stars. This laser system prototype will also be used for preflight tests of the ESUO Super Pressure Balloon mission.

14- by 22-Foot Subsonic Tunnel Laser Velocimeter Upgrade

NASA Technical Reports Server (NTRS)

Meyers, James F.; Lee, Joseph W.; Cavone, Angelo A.; Fletcher, Mark T.

2012-01-01

A long-focal length laser velocimeter constructed in the early 1980's was upgraded using current technology to improve usability, reliability and future serviceability. The original, free-space optics were replaced with a state-of-the-art fiber-optic subsystem which allowed most of the optics, including the laser, to be remote from the harsh tunnel environment. General purpose high-speed digitizers were incorporated in a standard modular data acquisition system, along with custom signal processing software executed on a desktop computer, served as the replacement for the signal processors. The resulting system increased optical sensitivity with real-time signal/data processing that produced measurement precisions exceeding those of the original system. Monte Carlo simulations, along with laboratory and wind tunnel investigations were used to determine system characteristics and measurement precision.

The Modernization of a Long-Focal Length Fringe-Type Laser Velocimeter

NASA Technical Reports Server (NTRS)

Meyers, James F.; Lee, Joseph W.; Cavone, Angelo A.; Fletcher, Mark T.

2012-01-01

A long-focal length laser velocimeter constructed in the early 1980's was upgraded using current technology to improve usability, reliability and future serviceability. The original, free-space optics were replaced with a state-of-the-art fiber-optic subsystem which allowed most of the optics, including the laser, to be remote from the harsh tunnel environment. General purpose high-speed digitizers were incorporated in a standard modular data acquisition system, along with custom signal processing software executed on a desktop computer, served as the replacement for the signal processors. The resulting system increased optical sensitivity with real-time signal/data processing that produced measurement precisions exceeding those of the original system. Monte Carlo simulations, along with laboratory and wind tunnel investigations were used to determine system characteristics and measurement precision.

Integrated optical biosensor system (IOBS)

DOEpatents

Grace, Karen M.; Sweet, Martin R.; Goeller, Roy M.; Morrison, Leland Jean; Grace, Wynne Kevin; Kolar, Jerome D.

2007-10-30

An optical biosensor has a first enclosure with a pathogen recognition surface, including a planar optical waveguide and grating located in the first enclosure. An aperture is in the first enclosure for insertion of sample to be investigated to a position in close proximity to the pathogen recognition surface. A laser in the first enclosure includes means for aligning and means for modulating the laser, the laser having its light output directed toward said grating. Detection means are located in the first enclosure and in optical communication with the pathogen recognition surface for detecting pathogens after interrogation by the laser light and outputting the detection. Electronic means is located in the first enclosure and receives the detection for processing the detection and outputting information on the detection, and an electrical power supply is located in the first enclosure for supplying power to the laser, the detection means and the electronic means.

Miniature Tunable Laser Spectrometer for Detection of a Trace Gas

NASA Technical Reports Server (NTRS)

Christensen, Lance E. (Inventor)

2017-01-01

An open-path laser spectrometer (OPLS) for measuring a concentration of a trace gas, the OPLS including an open-path multi-pass analysis region including a first mirror, a second mirror at a distance and orientation from the first mirror, and a support structure for locating the mirrors, a laser coupled to the analysis region and configured to emit light of a wavelength range and to enable a plurality of reflections of the emitted light between the mirrors, a detector coupled to the analysis region and configured to detect a portion of the emitted light impinging on the detector and to generate a corresponding signal, and an electronic system coupled to the laser and the detector, and configured to adjust the wavelength range of the emitted light from the laser based on the generated signal, and to measure the concentration of the trace gas based on the generated signal.

A study on the clinical characteristics of treating nevus of Ota by Q-switched Nd:YAG laser.

PubMed

Yan, Liu; Di, Li; Weihua, Wang; Feng, Liu; Ruilian, Li; Jun, Zhou; Hui, Su; Zhaoxia, Ying; Weihui, Zeng

2018-01-01

The purpose of this study was to retrospectively analyze the clinical characteristics of treating nevus of Ota by Q-switched Nd:YAG laser in Laser Cosmetology Center of Department of Dermatology, the Second Hospital, Xi'an Jiaotong University. The data of 1168 patients of nevus of Ota were analyzed retrospectively, which included the correlation among lesion color, treatment sessions, sex, age, lesion types, and effect. The Q-switched (QS) Nd:YAG laser system had a higher number of treatment sessions which were positively associated with a better response to treatment. Other variables, including gender, age, the categorization of the lesion according to Tanino's classification, and the color of the lesion, were not associated with the response to treatment. The treatment of nevus of Ota with QS Nd:YAG laser is safe and effective, with rare complications.

A 3-component laser-Doppler velocimeter data acquisition and reduction system

NASA Technical Reports Server (NTRS)

Rodman, L. C.; Bell, J. H.; Mehta, R. D.

1985-01-01

A laser doppler velocimeter capable of measuring all three components of velocity simultaneously in low-speed flows is described. All the mean velocities, Reynolds stresses, and higher-order products can be evaluated. The approach followed is to split one of the two colors used in a 2-D system, thus creating a third set of beams which is then focused in the flow from an off-axis direction. The third velocity component is computed from the known geometry of the system. The laser optical hardware and the data acquisition electronics are described in detail. In addition, full operating procedures and listings of the software (written in BASIC and ASSEMBLY languages) are also included. Some typical measurements obtained with this system in a vortex/mixing layer interaction are presented and compared directly to those obtained with a cross-wire system.

Wideband 1.064 micrometer detector evaluation

NASA Technical Reports Server (NTRS)

Green, S. I.

1975-01-01

The performance of several candidate detectors for use as communications detectors in a 400 Mbps 1.064 micrometers laser communication system was evaluated. The results of communication system Bit Error Rate (BER) testing for the best detector of each type are summarized. Complete testing data of each type detector is presented. The 400 Mbps 1.064 micrometers communication system receiver test bed is described. The best communication system results for each detector type are included. Performance comparisons are made at 0.000001 BER, the specification level chosen for satellite laser communication links. The data is presented in two groups. The first indicates the best performance levels that can be expected on normal space laser communication system operation. The second cites the best performance levels which can be achieved by focusing the signal to diffraction limited spots on the photosensitive area.

The aero optics effect on near space laser communication optical system

NASA Astrophysics Data System (ADS)

Hu, Yuan; Fu, Yuegang; Jiang, Huilin

2013-08-01

With the developing of the space laser communication link, the performance index including higher transfer speed, extending transfer distance, and environmental adaptability, all ask the system accuracy and indexes improving. Special the developing near space platform, its environmental is extremes, the near space drone and other airplane flight speed is very quickly from the subsonic to supersonic. The aero optics effect caused by high speed will generate a thin turbulent air layer. It affects the performance of laser communication optical system by laser light vibration, deviation and so on, further more affects the performance of laser communication system working performance, even can't communication. Therefore, for achieving optical system indexes, we need do more research in optical system near space aero optics environmental adaptability. In this paper, near space link environmental characteristic are researched. And on the base of the aero optics theory, computer simulating method is applied to analyze the relationship among the altitude, the flight speed and the image dispersion. The result shows that, the aero optics effect cannot be ignored when the terminal is in low altitude or is moving with supersonic speed. The effect must be taken into considered from overall design. The result will provide the basis of research design.

Lidar instruments proposed for Eos

NASA Technical Reports Server (NTRS)

Grant, William B.; Browell, Edward V.

1990-01-01

Lidar, an acronym for light detection and ranging, represents a class of instruments that utilize lasers to send probe beams into the atmosphere or onto the surface of the Earth and detect the backscattered return in order to measure properties of the atmosphere or surface. The associated technology has matured to the point where two lidar facilities, Geodynamics Laser Ranging System (GLRS), and Laser Atmospheric Wind Sensor (LAWS) were accepted for Phase 2 studies for Eos. A third lidar facility Laser Atmospheric Sounder and Altimeter (LASA), with the lidar experiment EAGLE (Eos Atmospheric Global Lidar Experiment) was proposed for Eos. The generic lidar system has a number of components. They include controlling electronics, laser transmitters, collimating optics, a receiving telescope, spectral filters, detectors, signal chain electronics, and a data system. Lidar systems that measure atmospheric constituents or meteorological parameters record the signal versus time as the beam propagates through the atmosphere. The backscatter arises from molecular (Rayleigh) and aerosol (Mie) scattering, while attenuation arises from molecular and aerosol scattering and absorption. Lidar systems that measure distance to the Earth's surface or retroreflectors in a ranging mode record signals with high temporal resolution over a short time period. The overall characteristics and measurements objectives of the three lidar systems proposed for Eos are given.

MEMS scanner mirror based system for retina scanning and in eye projection

NASA Astrophysics Data System (ADS)

Woittennek, Franziska; Knobbe, Jens; Pügner, Tino; Dallmann, Hans-Georg; Schelinski, Uwe; Grüger, Heinrich

2015-02-01

Many applications could benefit from miniaturized systems to scan blood vessels behind the retina in the human eye, so called "retina scanning". This reaches from access control to sophisticated security applications and medical devices. High volume systems for consumer applications require low cost and a user friendly operation. For example this includes no need for removal of glasses and self-adjustment, in turn guidance of focus and point of attraction by simultaneous projection for the user. A new system has been designed based on the well-known resonantly driven 2-d scanner mirror of Fraunhofer IPMS. A combined NIR and VIS laser system illuminates the eye through an eye piece designed for an operating distance allowing the use of glasses and granting sufficient field of view. This usability feature was considered to be more important than highest miniaturization. The modulated VIS laser facilitates the projection of an image directly onto the retina. The backscattered light from the continuous NIR laser contains the information of the blood vessels and is detected by a highly sensitive photo diode. A demonstrational setup has been realized including readout and driving electronics. The laser power was adjusted to an eye-secure level. Additional security features were integrated. Test measurements revealed promising results. In a first demonstration application the detection of biometric pattern of the blood vessels was evaluated for issues authentication in.

Range Imaging without Moving Parts

NASA Technical Reports Server (NTRS)

Blair, J. Bryan; Scott, V. Stanley, III; Ramos-Izquierdo, Luis

2008-01-01

Range-imaging instruments of a type now under development are intended to generate the equivalent of three-dimensional images from measurements of the round-trip times of flight of laser pulses along known directions. These instruments could also provide information on characteristics of targets, including roughnesses and reflectivities of surfaces and optical densities of such semi-solid objects as trees and clouds. Unlike in prior range-imaging instruments based on times of flight along known directions, there would be no moving parts; aiming of the laser beams along the known directions would not be accomplished by mechanical scanning of mirrors, prisms, or other optical components. Instead, aiming would be accomplished by using solid-state devices to switch input and output beams along different fiber-optic paths. Because of the lack of moving parts, these instruments could be extraordinarily reliable, rugged, and long-lasting. An instrument of this type would include an optical transmitter that would send out a laser pulse along a chosen direction to a target. An optical receiver coaligned with the transmitter would measure the temporally varying intensity of laser light reflected from the target to determine the distance and surface characteristics of the target. The transmitter would be a combination of devices for generating precise directional laser illumination. It would include a pulsed laser, the output of which would be coupled into a fiber-optic cable with a fan-out and solid-state optical switches that would enable switching of the laser beam onto one or more optical fibers terminated at known locations in an array on a face at the focal plane of a telescope. The array would be imaged by the telescope onto the target space. The receiver optical system could share the aforementioned telescope with the transmitter or could include a separate telescope aimed in the same direction as that of the transmitting telescope. In either case, light reflected from the target would be focused by the receiver optical system onto an array of optical fibers matching the array in the transmitter. These optical fibers would couple the received light to one or more photodetector( s). Optionally, the receiver could include solid-state optical switches for choosing which optical fiber(s) would couple light to the photodetector(s). This instrument architecture is flexible and can be optimized for a wide variety of applications and levels of performance. For example, it is scalable to any number of pixels and pixel resolutions and is compatible with a variety of ranging and photodetection methodologies, including, for example, ranging by use of modulated (including pulsed and encoded) light signals. The use of fixed arrays of optical fibers to generate controlled illumination patterns would eliminate the mechanical complexity and much of the bulk of optomechanical scanning assemblies. Furthermore, digital control of the selection of the fiber-optic pathways for the transmitted beams could afford capabilities not seen in previous three-dimensional range-imaging systems. Instruments of this type could be specialized for use as, for example, proximity detectors, three-dimensional robotic vision systems, airborne terrain-mapping systems, and inspection systems.

Applications of optical sensing for laser cutting and drilling.

PubMed

Fox, Mahlen D T; French, Paul; Peters, Chris; Hand, Duncan P; Jones, Julian D C

2002-08-20

Any reliable automated production system must include process control and monitoring techniques. Two laser processing techniques potentially lending themselves to automation are percussion drilling and cutting. For drilling we investigate the performance of a modification of a nonintrusive optical focus control system we previously developed for laser welding, which exploits the chromatic aberrations of the processing optics to determine focal error. We further developed this focus control system for closed-loop control of laser cutting. We show that an extension of the technique can detect deterioration in cut quality, and we describe practical trials carried out on different materials using both oxygen and nitrogen assist gas. We base our techniques on monitoring the light generated by the process, captured nonintrusively by the effector optics and processed remotely from the workpiece. We describe the relationship between the temporal and the chromatic modulation of the detected light and process quality and show how the information can be used as the basis of a process control system.

Improved Main Shaft Seal Life in Gas Turbines Using Laser Surface Texturing

NASA Astrophysics Data System (ADS)

McNickle, Alan D.; Etsion, Izhak

2002-10-01

This paper presents a general overview of the improved main shaft seal life in gas turbines using laser surface texturing (LST). The contents include: 1) Laser Surface Texturing System; 2) Seal Schematic with LST applied; 3) Dynamic Rig Tests; 4) Surface Finish Definitions; 5) Wear Test Rig; 6) Dynamic Test Rig; 7) Seal Cross Section-Rig Test; and 8) Typical Test Results. This paper is in viewgraph form.

Cryogenic Eyesafer Laser Optimization for Use Without Liquid Nitrogen

DTIC Science & Technology

2014-02-01

liquid cryogens. This calls for optimal performance around 125–150 K—high enough for reasonably efficient operation of a Stirling cooler. We...state laser system with an optimum operating temperature somewhat higher—ideally 125–150 K—can be identified, then a Stirling cooler can be used to...needed to optimize laser performance in the desired temperature range. This did not include actual use of Stirling coolers, but rather involved both

A new concept in laser-assisted chemistry - The electronic-field representation

NASA Technical Reports Server (NTRS)

George, T. F.; Zimmerman, I. H.; Yuan, J.-M.; Laing, J. R.; Devries, P. L.

1977-01-01

Electronic-field representation is proposed as a technique for laser-assisted chemistry. Specifically, it is shown that several field-assisted chemical processes can be described in terms of mixed matter-field quantum states and their associated energies. The technique may be used to analyze the effects exerted by an intense laser on both bound and unbound molecular systems, and to investigate other field-induced effects including multiphoton processes, emission, and photodissociation.

Laser Research

NASA Technical Reports Server (NTRS)

1979-01-01

Eastman Kodak Company, Rochester, New York is a broad-based firm which produces photographic apparatus and supplies, fibers, chemicals and vitamin concentrates. Much of the company's research and development effort is devoted to photographic science and imaging technology, including laser technology. Eastman Kodak is using a COSMIC computer program called LACOMA in the analysis of laser optical systems and camera design studies. The company reports that use of the program has provided development time savings and reduced computer service fees.

Pulsed and CW adjustable 1942 nm single-mode all-fiber Tm-doped fiber laser system for surgical laser soft tissue ablation applications.

PubMed

Huang, Yize; Jivraj, Jamil; Zhou, Jiaqi; Ramjist, Joel; Wong, Ronnie; Gu, Xijia; Yang, Victor X D

2016-07-25

A surgical laser soft tissue ablation system based on an adjustable 1942 nm single-mode all-fiber Tm-doped fiber laser operating in pulsed or CW mode with nitrogen assistance is demonstrated. Ex vivo ablation on soft tissue targets such as muscle (chicken breast) and spinal cord (porcine) with intact dura are performed at different ablation conditions to examine the relationship between the system parameters and ablation outcomes. The maximum laser average power is 14.4 W, and its maximum peak power is 133.1 W with 21.3 μJ pulse energy. The maximum CW power density is 2.33 × 10⁶ W/cm² and the maximum pulsed peak power density is 2.16 × 10⁷ W/cm². The system parameters examined include the average laser power in CW or pulsed operation mode, gain-switching frequency, total ablation exposure time, and the input gas flow rate. The ablation effects were measured by microscopy and optical coherence tomography (OCT) to evaluate the ablation depth, superficial heat-affected zone diameter (HAZD) and charring diameter (CD). Our results conclude that the system parameters can be tailored to meet different clinical requirements such as ablation for soft tissue cutting or thermal coagulation for future applications of hemostasis.

Airborne water vapor DIAL system and measurements of water and aerosol profiles

NASA Technical Reports Server (NTRS)

Higdon, Noah S.; Browell, Edward V.

1991-01-01

The Lidar Applications Group at NASA Langley Research Center has developed a differential absorption lidar (DIAL) system for the remote measurement of atmospheric water vapor (H2O) and aerosols from an aircraft. The airborne H2O DIAL system is designed for extended flights to perform mesoscale investigations of H2O and aerosol distributions. This DIAL system utilizes a Nd:YAG-laser-pumped dye laser as the off-line transmitter and a narrowband, tunable Alexandrite laser as the on-line transmitter. The dye laser has an oscillator/amplifier configuration which incorporates a grating and prism in the oscillator cavity to narrow the output linewidth to approximately 15 pm. This linewidth can be maintained over the wavelength range of 725 to 730 nm, and it is sufficiently narrow to satisfy the off-line spectral requirements. In the Alexandrite laser, three intracavity tuning elements combine to produce an output linewidth of 1.1 pm. These spectral devices include a five-plate birefringent tuner, a 1-mm thick solid etalon and a 1-cm air-spaced etalon. A wavelength stability of +/- 0.35 pm is achieved by active feedback control of the two Fabry-Perot etalons using a frequency stabilized He-Ne laser as a wavelength reference. The three tuning elements can be synchronously scanned over a 150 pm range with microprocessor-based scanning electronics. Other aspects of the DIAL system are discussed.

Proceedings of Workshop on Laser Diagnostics in Fluid Mechanics and Combustion

NASA Astrophysics Data System (ADS)

1993-10-01

Proceedings of the Workshop on Laser Diagnostics in Fluid Mechanics and Combustion are presented. Topics included are: Accuracy of Laser Doppler Anemometry; Applications of Raman-Rayleigh-LIF Diagnostics in Combustion Research; Phase Doppler Anemometer Technique Concepts and Applications; CARS; Particle Image Velocimetry; Practical Consideration in the Use and Design of Laser Velocimetry Systems in Turbomachinery Applications; Phase Doppler Measurements of Gas-Particle Flow Through a Tube Bank; Degenerate Four Wave Mixing for Shock Tunnel Studies of Supersonic Combustion; Laser Induced Photodissociation and Fluorescence (LIPF) of Sodium Species Present in Coal Combustion; 3D Holographic Measurements Inside a Spark Ignition Engine; Laser Doppler Velocimeter Measurements in Compressible Flow; Bursting in a Tornado Vortex; Quantitative Imaging of OH and Temperature Using a Single Laser Source and Single Intensified Camera; and Laser Doppler Measurements Inside an Artificial Heart Valve.

Free-flying experiment to measure the Schawlow-Townes linewidth limit of a 300 THz laser oscillator

NASA Technical Reports Server (NTRS)

Byer, R. L.; Byvik, C. E.

1988-01-01

Recent advances in laser diode-pumped solid state laser sources permit the design and testing of laser sources with linewidths that approach the Schawlow-Townes limit of 1 Hz/mW of output power. Laser diode pumped solid state ring oscillators have been operated with CW output power levels of 25 mW at electrical efficiencies that exceed 6 percent. These oscillators are expected to operate for lifetimes that approach those of the laser diode sources which is now approaching 20,000 hours. The efficiency and lifetime of these narrow linewidth laser sources will enable space measurements of gravity waves, remote sensing applications (including local range rate and measurements), and laser sources for frequency and time standards. A free-flight experiment, 'SUNLITE', is being designed to measure the linewidth of this all-solid-state laser system.

Optimizing Frozen Sample Preparation for Laser Microdissection: Assessment of CryoJane Tape-Transfer System®

PubMed Central

Golubeva, Yelena G.; Smith, Roberta M.; Sternberg, Lawrence R.

2013-01-01

Laser microdissection is an invaluable tool in medical research that facilitates collecting specific cell populations for molecular analysis. Diversity of research targets (e.g., cancerous and precancerous lesions in clinical and animal research, cell pellets, rodent embryos, etc.) and varied scientific objectives, however, present challenges toward establishing standard laser microdissection protocols. Sample preparation is crucial for quality RNA, DNA and protein retrieval, where it often determines the feasibility of a laser microdissection project. The majority of microdissection studies in clinical and animal model research are conducted on frozen tissues containing native nucleic acids, unmodified by fixation. However, the variable morphological quality of frozen sections from tissues containing fat, collagen or delicate cell structures can limit or prevent successful harvest of the desired cell population via laser dissection. The CryoJane Tape-Transfer System®, a commercial device that improves cryosectioning outcomes on glass slides has been reported superior for slide preparation and isolation of high quality osteocyte RNA (frozen bone) during laser dissection. Considering the reported advantages of CryoJane for laser dissection on glass slides, we asked whether the system could also work with the plastic membrane slides used by UV laser based microdissection instruments, as these are better suited for collection of larger target areas. In an attempt to optimize laser microdissection slide preparation for tissues of different RNA stability and cryosectioning difficulty, we evaluated the CryoJane system for use with both glass (laser capture microdissection) and membrane (laser cutting microdissection) slides. We have established a sample preparation protocol for glass and membrane slides including manual coating of membrane slides with CryoJane solutions, cryosectioning, slide staining and dissection procedure, lysis and RNA extraction that facilitated efficient dissection and high quality RNA retrieval from CryoJane preparations. CryoJane technology therefore has the potential to facilitate standardization of laser microdissection slide preparation from frozen tissues. PMID:23805281

The technology on noise reduction of the APD detection circuit

NASA Astrophysics Data System (ADS)

Wu, Xue-ying; Zheng, Yong-chao; Cui, Jian-yong

2013-09-01

The laser pulse detection is widely used in the field of laser range finders, laser communications, laser radar, laser Identification Friend or Foe, et al, for the laser pulse detection has the advantage of high accuracy, high sensitivity and strong anti-interference. The avalanche photodiodes (APD) has the advantage of high quantum efficiency, high response speed and huge gain. The APD is particularly suitable for weak signal detection. The technology that APD acts as the photodetector for weak signal reception and amplification is widely used in laser pulse detection. The APD will convert the laser signal to weak electrical signal. The weak signal is amplified, processed and exported by the circuit. In the circuit design, the optimal signal detection is one key point in photoelectric detection system. The issue discusses how to reduce the noise of the photoelectric signal detection circuit and how to improve the signal-to-noise ratio, related analysis and practice included. The essay analyzes the mathematical model of the signal-to-noise ratio for photoelectric conversion and the noise of the APD photoelectric detection system. By analysis the bandwidth of the detection system is determined, and the circuit devices are selected that match the APD. In the circuit design separated devices with low noise are combined with integrated operational amplifier for the purpose of noise reduction. The methods can effectively suppress the noise, and improve the detection sensitivity.

Fundamental Studies of Ignition Process in Large Natural Gas Engines Using Laser Spark Ignition

DOE Office of Scientific and Technical Information (OSTI.GOV)

Azer Yalin; Bryan Willson

Past research has shown that laser ignition provides a potential means to reduce emissions and improve engine efficiency of gas-fired engines to meet longer-term DOE ARES (Advanced Reciprocating Engine Systems) targets. Despite the potential advantages of laser ignition, the technology is not seeing practical or commercial use. A major impediment in this regard has been the 'open-path' beam delivery used in much of the past research. This mode of delivery is not considered industrially practical owing to safety factors, as well as susceptibility to vibrations, thermal effects etc. The overall goal of our project has been to develop technologies andmore » approaches for practical laser ignition systems. To this end, we are pursuing fiber optically coupled laser ignition system and multiplexing methods for multiple cylinder engine operation. This report summarizes our progress in this regard. A partial summary of our progress includes: development of a figure of merit to guide fiber selection, identification of hollow-core fibers as a potential means of fiber delivery, demonstration of bench-top sparking through hollow-core fibers, single-cylinder engine operation with fiber delivered laser ignition, demonstration of bench-top multiplexing, dual-cylinder engine operation via multiplexed fiber delivered laser ignition, and sparking with fiber lasers. To the best of our knowledge, each of these accomplishments was a first.« less