Science.gov

Sample records for optical activity laser

  1. Active polarimeter optical system laser hazard analysis.

    SciTech Connect

    Augustoni, Arnold L.

    2005-07-01

    A laser hazard analysis was performed for the SNL Active Polarimeter Optical System based on the ANSI Standard Z136.1-2000, American National Standard for Safe Use of Lasers and the ANSI Standard Z136.6-2000, American National Standard for Safe Use of Lasers Outdoors. The Active Polarimeter Optical System (APOS) uses a pulsed, near-infrared, chromium doped lithium strontium aluminum fluoride (Cr:LiSAF) crystal laser in conjunction with a holographic diffuser and lens to illuminate a scene of interest. The APOS is intended for outdoor operations. The system is mounted on a height adjustable platform (6 feet to 40 feet) and sits atop a tripod that points the beam downward. The beam can be pointed from nadir to as much as 60 degrees off of nadir producing an illuminating spot geometry that can vary from circular (at nadir) to elliptical in shape (off of nadir). The JP Innovations crystal Cr:LiSAF laser parameters are presented in section II. The illuminating laser spot size is variable and can be adjusted by adjusting the separation distance between the lens and the holographic diffuser. The system is adjusted while platform is at the lowest level. The laser spot is adjusted for a particular spot size at a particular distance (elevation) from the laser by adjusting the separation distance (d{sub diffuser}) to predetermined values. The downward pointing angle is also adjusted before the platform is raised to the selected operation elevation.

  2. Laser-heating-based active optics for synchrotron radiation applications.

    PubMed

    Yang, Fugui; Li, Ming; Gao, Lidan; Sheng, Weifan; Liu, Peng; Zhang, Xiaowei

    2016-06-15

    Active optics has attracted considerable interest from researchers in synchrotron radiation facilities because of its capacity for x-ray wavefront correction. Here, we report a novel and efficient technique for correcting or modulating a mirror surface profile based on laser-heating-induced thermal expansion. An experimental study of the characteristics of the surface thermal deformation response indicates that the power of a milliwatt laser yields a bump height as low as the subnanometer scale and that the variation of the spot size modulates the response function width effectively. In addition, the capacity of the laser-heating technique for free-form surface modulation is demonstrated via a one-dimensional surface correction experiment. The developed method is a promising new approach toward effective x-ray active optics coupled with at-wavelength metrology techniques.

  3. Optical Properties of Active Regions in Terahertz Quantum Cascade Lasers

    NASA Astrophysics Data System (ADS)

    Dyksik, M.; Motyka, M.; Rudno-Rudziński, W.; Sęk, G.; Misiewicz, J.; Pucicki, D.; Kosiel, K.; Sankowska, I.; Kubacka-Traczyk, J.; Bugajski, M.

    2016-07-01

    In this work, AlGaAs/GaAs superlattice, with layers' sequence and compositions imitating the active and injector regions of a quantum cascade laser designed for emission in the terahertz spectral range, was investigated. Three independent absorption-like optical spectroscopy techniques were employed in order to study the band structure of the minibands formed within the conduction band. Photoreflectance measurements provided information about interband transitions in the investigated system. Common transmission spectra revealed, in the target range of intraband transitions, mainly a number of lines associated with the phonon-related processes, including two-phonon absorption. In contrast, differential transmittance realized by means of Fourier-transform spectroscopy was utilized to probe the confined states of the conduction band. The obtained energy separation between the second and third confined electron levels, expected to be predominantly contributing to the lasing, was found to be ~9 meV. The optical spectroscopy measurements were supported by numerical calculations performed in the effective mass approximation and XRD measurements for layers' width verification. The calculated energy spacings are in a good agreement with the experimental values.

  4. Active mode-locked lasers and other photonic devices using electro-optic whispering gallery mode resonators

    NASA Technical Reports Server (NTRS)

    Matsko, Andrey B. (Inventor); Ilchenko, Vladimir (Inventor); Savchenkov, Anatoliy (Inventor); Maleki, Lutfollah (Inventor)

    2006-01-01

    Techniques and devices using whispering gallery mode (WGM) optical resonators, where the optical materials of the WGM resonators exhibit an electro-optical effect to perform optical modulation. Examples of actively mode-locked lasers and other devices are described.

  5. Actively mode-locked fiber laser using acousto-optic modulator

    NASA Astrophysics Data System (ADS)

    Nikodem, Michal P.; Sergeant, Hendrik; Kaczmarek, Pawel; Abramski, Krzysztof M.

    2008-12-01

    In recent years we have observed growing interest in mode-locked fiber lasers. Development of erbium doped fiber (EDF) amplifiers and WDM technique made 3rd telecommunication window extremely interesting region for ultrafast optics. The main advantages of fiber lasers i.e. narrow linewidth and wide gain bandwidth make them very attractive sources in various applications. In this paper we present an actively mode-locked erbium doped fiber ring laser. Modelocking is obtained using an acousto-optic modulator (AOM) coupled into the laser cavity. The impact of different parameters (e.g. light polarization, modulation frequency) is investigated. We study mechanisms of controlling the wavelength of the laser.

  6. Laser optical disk position encoder with active heads

    NASA Technical Reports Server (NTRS)

    Osborne, Eric P.

    1991-01-01

    An angular position encoder that minimizes the effects of eccentricity and other misalignments between the disk and the read stations by employing heads with beam steering optics that actively track the disk in directions along the disk radius and normal to its surface is discussed. The device adapts features prevalent in optical disk technology to the application of angular position sensing.

  7. Complex Active Optical Networks as a New Laser Concept.

    PubMed

    Lepri, Stefano; Trono, Cosimo; Giacomelli, Giovanni

    2017-03-24

    Complex optical networks containing one or more gain sections are investigated, and the evidence of lasing action is reported; the emission spectrum reflects the topological disorder induced by the connections. A theoretical description compares well with the measurements, mapping the networks to directed graphs and showing the analogies with the problem of quantum chaos on graphs. We show that the interplay of chaotic diffusion and amplification leads to an emission statistic with characteristic heavy tails: for different topologies, an unprecedented experimental demonstration of Lévy statistics expected for random lasers is here provided for a continuous-wave pumped system. This result is also supported by a Monte Carlo simulation based on the ray random walk on the graph.

  8. Complex Active Optical Networks as a New Laser Concept

    NASA Astrophysics Data System (ADS)

    Lepri, Stefano; Trono, Cosimo; Giacomelli, Giovanni

    2017-03-01

    Complex optical networks containing one or more gain sections are investigated, and the evidence of lasing action is reported; the emission spectrum reflects the topological disorder induced by the connections. A theoretical description compares well with the measurements, mapping the networks to directed graphs and showing the analogies with the problem of quantum chaos on graphs. We show that the interplay of chaotic diffusion and amplification leads to an emission statistic with characteristic heavy tails: for different topologies, an unprecedented experimental demonstration of Lévy statistics expected for random lasers is here provided for a continuous-wave pumped system. This result is also supported by a Monte Carlo simulation based on the ray random walk on the graph.

  9. Efficient high repetition rate electro-optic Q-switched laser with an optically active langasite crystal

    PubMed Central

    Ma, Shihui; Yu, Haohai; Zhang, Huaijin; Han, Xuekun; Lu, Qingming; Ma, Changqin; Boughton, Robert I.; Wang, Jiyang

    2016-01-01

    With an optically active langasite (LGS) crystal as the electro-optic Q-switch, we demonstrate an efficient Q-switched laser with a repetition rate of 200 kHz. Based on the theoretical analysis of the interaction between optical activity and electro-optic property, the optical activity of the crystal has no influence on the birefringence during Q-switching if the quarter wave plate used was rotated to align with the polarization direction. With a Nd:LuVO4 crystal possessing a large emission cross-section and a short fluorescence lifetime as the gain medium, a stable LGS Q-switched laser was designed with average output power of 4.39 W, corresponding to a slope efficiency of 29.4% and with a minimum pulse width of 5.1 ns. This work represents the highest repetition rate achieved so far in a LGS Q-switched laser and it can provide a practical Q-switched laser with a tunable high repetition rates for many applications, such as materials processing, laser ranging, medicine, military applications, biomacromolecule materials, remote sensing, etc. PMID:27461819

  10. Efficient high repetition rate electro-optic Q-switched laser with an optically active langasite crystal

    NASA Astrophysics Data System (ADS)

    Ma, Shihui; Yu, Haohai; Zhang, Huaijin; Han, Xuekun; Lu, Qingming; Ma, Changqin; Boughton, Robert I.; Wang, Jiyang

    2016-07-01

    With an optically active langasite (LGS) crystal as the electro-optic Q-switch, we demonstrate an efficient Q-switched laser with a repetition rate of 200 kHz. Based on the theoretical analysis of the interaction between optical activity and electro-optic property, the optical activity of the crystal has no influence on the birefringence during Q-switching if the quarter wave plate used was rotated to align with the polarization direction. With a Nd:LuVO4 crystal possessing a large emission cross-section and a short fluorescence lifetime as the gain medium, a stable LGS Q-switched laser was designed with average output power of 4.39 W, corresponding to a slope efficiency of 29.4% and with a minimum pulse width of 5.1 ns. This work represents the highest repetition rate achieved so far in a LGS Q-switched laser and it can provide a practical Q-switched laser with a tunable high repetition rates for many applications, such as materials processing, laser ranging, medicine, military applications, biomacromolecule materials, remote sensing, etc.

  11. Some results in laser optics

    NASA Astrophysics Data System (ADS)

    Timus, Clementina A.; Medianu, Rares V.; Georgescu, Claudian; Georgescu, Geo

    1996-05-01

    The experience in laser optics in the Laser Department of the Institute of Atomic Physics began with the development of the first He-Ne laser in Romania in 1962 (2 years later than the world's first). Optical polishing and optical coating technology have been developed primarily for the visible and IR ranges, with a continual effort to improve them to increase the quality of optical components and the implicit reliability of the lasers. Ever-increasing attention has had to be paid to the investigation, by optical and nonoptical methods, to characterize optical coatings. The correlation of coating characteristics with the deposition technologies could enable the improvement of the technology parameters. Since all the lasers and the applications are equipped with optical components realized in our laboratory, the observations of the users have been important in the activity of improving the quality of optics.

  12. Active lamp pulse driver circuit. [optical pumping of laser media

    NASA Technical Reports Server (NTRS)

    Logan, K. E. (Inventor)

    1983-01-01

    A flashlamp drive circuit is described which uses an unsaturated transistor as a current mode switch to periodically subject a partially ionized gaseous laser excitation flashlamp to a stable, rectangular pulse of current from an incomplete discharge of an energy storage capacitor. A monostable multivibrator sets the pulse interval, initiating the pulse in response to a flash command by providing a reference voltage to a non-inverting terminal of a base drive amplifier; a tap on an emitter resistor provides a feedback signal sensitive to the current amplitude to an inverting terminal of amplifier, thereby controlling the pulse amplitude. The circuit drives the flashlamp to provide a squarewave current flashlamp discharge.

  13. Active eye-tracking for an adaptive optics scanning laser ophthalmoscope

    PubMed Central

    Sheehy, Christy K.; Tiruveedhula, Pavan; Sabesan, Ramkumar; Roorda, Austin

    2015-01-01

    We demonstrate a system that combines a tracking scanning laser ophthalmoscope (TSLO) and an adaptive optics scanning laser ophthalmoscope (AOSLO) system resulting in both optical (hardware) and digital (software) eye-tracking capabilities. The hybrid system employs the TSLO for active eye-tracking at a rate up to 960 Hz for real-time stabilization of the AOSLO system. AOSLO videos with active eye-tracking signals showed, at most, an amplitude of motion of 0.20 arcminutes for horizontal motion and 0.14 arcminutes for vertical motion. Subsequent real-time digital stabilization limited residual motion to an average of only 0.06 arcminutes (a 95% reduction). By correcting for high amplitude, low frequency drifts of the eye, the active TSLO eye-tracking system enabled the AOSLO system to capture high-resolution retinal images over a larger range of motion than previously possible with just the AOSLO imaging system alone. PMID:26203370

  14. Active eye-tracking for an adaptive optics scanning laser ophthalmoscope.

    PubMed

    Sheehy, Christy K; Tiruveedhula, Pavan; Sabesan, Ramkumar; Roorda, Austin

    2015-07-01

    We demonstrate a system that combines a tracking scanning laser ophthalmoscope (TSLO) and an adaptive optics scanning laser ophthalmoscope (AOSLO) system resulting in both optical (hardware) and digital (software) eye-tracking capabilities. The hybrid system employs the TSLO for active eye-tracking at a rate up to 960 Hz for real-time stabilization of the AOSLO system. AOSLO videos with active eye-tracking signals showed, at most, an amplitude of motion of 0.20 arcminutes for horizontal motion and 0.14 arcminutes for vertical motion. Subsequent real-time digital stabilization limited residual motion to an average of only 0.06 arcminutes (a 95% reduction). By correcting for high amplitude, low frequency drifts of the eye, the active TSLO eye-tracking system enabled the AOSLO system to capture high-resolution retinal images over a larger range of motion than previously possible with just the AOSLO imaging system alone.

  15. Actively mode-locked fiber ring laser by intermodal acousto-optic modulation.

    PubMed

    Bello-Jiménez, M; Cuadrado-Laborde, C; Sáez-Rodríguez, D; Diez, A; Cruz, J L; Andrés, M V

    2010-11-15

    We report an actively mode-locked fiber ring laser. A simple and low-insertion-loss acousto-optic modulator driven by standing flexural waves, which couples core-to-cladding modes in a standard single-mode optical fiber, is used as an active mechanism for mode locking. Among the remarkable features of the modulator, we mention its high modulation depth (72%), broad bandwidth (187 GHz), easy tunability in the optical wavelength, and low insertion losses (0.7 dB). The narrowest optical pulses obtained were of 95 ps time width, 21 mW peak power, repetition rate of 4.758 MHz, and 110 mW of pump power.

  16. Short cavity active mode locking fiber laser for optical sensing and imaging

    NASA Astrophysics Data System (ADS)

    Lee, Hwi Don; Han, Ga Hee; Jeong, Syung Won; Jeong, Myung Yung; Kim, Chang-Seok; Shin, Jun Geun; Lee, Byeong Ha; Eom, Tae Joong

    2014-05-01

    We demonstrate a highly linear wavenumber- swept active mode locking (AML) fiber laser for optical sensing and imaging without any wavenumber-space resampling process. In this all-electric AML wavenumber-swept mechanism, a conventional wavelength selection filter is eliminated and, instead, the suitable programmed electric modulation signal is directly applied to the gain medium. Various types of wavenumber (or wavelength) tunings can be implemented because of the filter-less cavity configuration. Therefore, we successfully demonstrate a linearly wavenumber-swept AML fiber laser with 26.5 mW of output power to obtain an in-vivo OCT image at the 100 kHz swept rate.

  17. Active optics: variable curvature mirrors for ELT laser guide star refocusing systems

    NASA Astrophysics Data System (ADS)

    Challita, Zalpha; Hugot, Emmanuel; Madec, Fabrice; Ferrari, Marc; Le Mignant, David; Vivès, Sébastien; Cuby, Jean-Gabriel

    2011-10-01

    The future generation of Extremely Large Telescopes will require a complex combination of technologies for adaptive optics (AO) systems assisted by laser guide stars (LGS). In this context, the distance from the LGS spot to the telescope pupil ranges from about 80 to 200 km, depending on the Sodium layer altitude and the elevation of the telescope. This variation leads to a defocusing effect on the LGS wave-front sensor which needs to be compensated. We propose an active mirror able to compensate for this variation, based on an original optical design including this active optics component. This LGS Variable Curvature Mirror (LGS-VCM) is a 120 mm spherical active mirror able to achieve 820 μm deflection sag with an optical quality better than 150 nm RMS, allowing the radius of curvature variation from F/12 to F/2. Based on elasticity theory, the deformation of the metallic mirror is provided by an air pressure applied on a thin meniscus with a variable thickness distribution. In this article, we detail the analytical development leading to the specific geometry of the active component, the results of finite element analysis and the expected performances in terms of surface error versus the range of refocalisation. Three prototypes have been manufactured to compare the real behavior of the mirror and the simulations data. Results obtained on the prototypes are detailed, showing that the deformation of the VCM is very close to the simulation, and leads to a realistic active concept.

  18. Gigashot Optical Laser Demonstrator

    SciTech Connect

    Deri, R. J.

    2015-10-13

    The Gigashot Optical Laser Demonstrator (GOLD) project has demonstrated a novel optical amplifier for high energy pulsed lasers operating at high repetition rates. The amplifier stores enough pump energy to support >10 J of laser output, and employs conduction cooling for thermal management to avoid the need for expensive and bulky high-pressure helium subsystems. A prototype amplifier was fabricated, pumped with diode light at 885 nm, and characterized. Experimental results show that the amplifier provides sufficient small-signal gain and sufficiently low wavefront and birefringence impairments to prove useful in laser systems, at repetition rates up to 60 Hz.

  19. Fiber optic laser rod

    DOEpatents

    Erickson, G.F.

    1988-04-13

    A laser rod is formed from a plurality of optical fibers, each forming an individual laser. Synchronization of the individual fiber lasers is obtained by evanescent wave coupling between adjacent optical fiber cores. The fiber cores are dye-doped and spaced at a distance appropriate for evanescent wave coupling at the wavelength of the selected dye. An interstitial material having an index of refraction lower than that of the fiber core provides the optical isolation for effective lasing action while maintaining the cores at the appropriate coupling distance. 2 figs.

  20. Optical characterization of femtosecond laser induced active channel waveguides in lithium fluoride crystals

    NASA Astrophysics Data System (ADS)

    Chiamenti, I.; Bonfigli, F.; Gomes, A. S. L.; Michelotti, F.; Montereali, R. M.; Kalinowski, H. J.

    2014-01-01

    We successfully realized broad-band light-emitting color center waveguides buried in LiF crystals by using femtosecond laser pulses. The characterization of the waveguides was performed by optical microscopy, photoluminescence spectra, loss measurements and near-field profiling. The experimental results show that the direct-writing fabrication process induces low-index contrast active channel waveguides: their wavelength-dependent refractive index changes, estimated from 10-3 to 10-4 depending on the writing conditions, allow supporting few modes at visible and near-infrared wavelengths.

  1. Optical characterization of femtosecond laser induced active channel waveguides in lithium fluoride crystals

    SciTech Connect

    Chiamenti, I.; Kalinowski, H. J.; Bonfigli, F.; Montereali, R. M.; Gomes, A. S. L.; Michelotti, F.

    2014-01-14

    We successfully realized broad-band light-emitting color center waveguides buried in LiF crystals by using femtosecond laser pulses. The characterization of the waveguides was performed by optical microscopy, photoluminescence spectra, loss measurements and near-field profiling. The experimental results show that the direct-writing fabrication process induces low-index contrast active channel waveguides: their wavelength-dependent refractive index changes, estimated from 10{sup −3} to 10{sup −4} depending on the writing conditions, allow supporting few modes at visible and near-infrared wavelengths.

  2. An actively Q-switched single-longitudinal-mode fiber laser with an optically pumped saturable absorber

    NASA Astrophysics Data System (ADS)

    Yun, Hyo-Geun; Lee, Seoung Hun; Lee, Min Hee; Kim, Kyong Hon

    2013-09-01

    We have demonstrated an actively Q-switched single-longitudinal-mode (SLM) erbium-doped fiber (EDF) ring laser by using an EDF saturable absorber modulated under an external laser pulse injection. A laser output of 1531.9 nm wavelength from a distributed-feedback laser diode was amplified with an EDF amplifier and modulated with an external electro-optical modulator, and the modulated signals were used as control pulses to saturate the EDF saturable absorber for the actively Q-switched ring-type fiber laser operation. Actively Q-switched 1542 nm wavelength laser pulses of 4.5 nJ pulse energy and of 4.0μs pulse width were achieved at a repetition rate of 100 Hz. When the Q-switched laser pulse energy was reduced to about 0.54 nJ by decreasing the gain-pump power used for exciting the ring cavity and the control-pulse beam power used for bleaching out the saturable absorber, the SLM laser pulses were achieved. Further improvement of the Q-switched SLM laser pulse output can be achieved simply by using an external laser amplifier and by shortening the cavity length with short pigtailed-fiber laser components, and thus the SLM laser pulses can be useful for various applications.

  3. A linear optical trap with active medium for experiments with high power laser pulses

    NASA Astrophysics Data System (ADS)

    Mohamed, Tarek; Andler, Guillermo; Schuch, Reinhold

    2015-02-01

    A linear optical trap for circulating high power laser pulses and tuning these pulses to high repetition frequency of several tens of MHz has been developed. A ns excimer pumped dye laser pulse has been injected with help of a Wollaston prism and a synchronized Pockels cell into an optical trap formed by two highly reflecting mirrors in a linear configuration. The test was done at λ = 580 nm, but the optical trap can be used without limitations in a broad band of optical wavelengths (400-700 nm). Power considerations give an increase of the efficiency of the optical trap of about 7 times compared to single passage of the laser pulse through the experimental section. The time structure of the trapped laser pulses can be controlled by changing the distance between the two high reflecting mirrors. The efficiency of the optical trap strongly depends upon optical losses. To compensate the optical losses, an amplifying cell was introduced, and the efficiency was about 60 times higher than that by single passage of the laser pulse through the experimental section.

  4. A linear optical trap with active medium for experiments with high power laser pulses.

    PubMed

    Mohamed, Tarek; Andler, Guillermo; Schuch, Reinhold

    2015-02-01

    A linear optical trap for circulating high power laser pulses and tuning these pulses to high repetition frequency of several tens of MHz has been developed. A ns excimer pumped dye laser pulse has been injected with help of a Wollaston prism and a synchronized Pockels cell into an optical trap formed by two highly reflecting mirrors in a linear configuration. The test was done at λ = 580 nm, but the optical trap can be used without limitations in a broad band of optical wavelengths (400-700 nm). Power considerations give an increase of the efficiency of the optical trap of about 7 times compared to single passage of the laser pulse through the experimental section. The time structure of the trapped laser pulses can be controlled by changing the distance between the two high reflecting mirrors. The efficiency of the optical trap strongly depends upon optical losses. To compensate the optical losses, an amplifying cell was introduced, and the efficiency was about 60 times higher than that by single passage of the laser pulse through the experimental section.

  5. Intracavity optical parametric oscillator pumped by an actively Q-switched Nd:YAG laser

    NASA Astrophysics Data System (ADS)

    Liu, Z. J.; Wang, Q. P.; Zhang, X. Y.; Liu, Z. J.; Wang, H.; Chang, J.; Fan, S. Z.; Ma, F. S.; Jin, G. F.

    2008-03-01

    A non-critically phase-matched KTiOPO4 optical parametric oscillator (OPO) intracavity pumped by a laser diode end-pumped acousto-optically Q-switchedNd:YAG laser is experimentally demonstrated. The highest average power is obtained at the pulse repetition rate (PRR) of around 15 kHz, which is different from the widely reported Nd:YVO4 laser pumped OPO in which the highest average power is obtained at a very high PRR, e.g. 80 kHz. With an incident laser diode power of 6.93 W and a pulse repetition rate of 15 kHz, an average signal power of 0.72 W is obtained with a peak power of 7.7 kW and an optical-to-optical conversion efficiency of 10.4%.

  6. Laser Rangefinder Optics

    NASA Astrophysics Data System (ADS)

    Roberts, D. Allan

    1986-07-01

    The optics in a laser rangefinder must perform three separate functions: transmitter divergence control, receiver energy collection, and aiming sensor imaging. In addition, boresight may need to be monitored. The design of these optics is driven primarily by the rangefinder packaging constraints, which limit both the external window size and the internal space available. System considerations such as range, target, propagation, package, and safety are used to determine the required optical apertures, fields, divergence, and resolution. Often, the total area of the transmitter, receiver, and sensor apertures cannot be accommodated by the front of the package, in which case functions must be combined. Sensor optics depend somewhat on the specific sensor (eye, TV, FLIR), but usually require the biggest possible aperture with near diffraction-limited performance. Laser beam expanders are usually some form of Galilean telescope, and often present serious Narcissus and damage problems. Receiver optics look simple, but narrow filters and small detectors can make them quite sophisticated. Boresight optics are sometimes required to monitor the alignment of the laser beam to the sensor reticle. Some specific design suggestions are made, with emphasis on those problems which are peculiar to laser range-finders. These designs emphasize high-power pulsed lasers and diffuse targets, since they are the most common and present some of the greatest challenges.

  7. Lasers for bio-optics

    NASA Astrophysics Data System (ADS)

    Sona, Alberto

    1992-03-01

    Lasers are being increasingly used in bioptics and in life sciences in general, especially for medical applications for therapy and diagnostics. Lasers are also broadly used in environment sciences to monitor atmospheric parameters and concentrations of molecular species of natural origin or coming from human activities such as the various kind of pollutants. The peculiar features of lasers exploited in these areas are mainly the capability of developing an action or performing a measurement without physical contact with the target and, if required, from a remote position with the assistance of suitable beam delivery systems such as telescopes, microscopes, or optical fibers. These features are directly related to the space and time coherence of the laser light and to the energy storage capability of the laser material which allow an extremely effective concentration of the beam energy in space, direction frequency, or time. A short description of the principle of operation and relevant properties of lasers are given and the most significant properties of the laser emission are briefly reviewed. Lasers for medical applications (mainly for therapy) will be mentioned, pointing out the specific property exploited for the various applications. Finally, examples of laser applications to the environmental sciences will be reported. A summary of the properties exploited in the various bio-optical applications is shown.

  8. Characterization of wavelength-swept active mode locking fiber laser based on reflective semiconductor optical amplifier

    NASA Astrophysics Data System (ADS)

    Lee, Hwi Don; Lee, Ju Han; Yung Jeong, Myung; Kim, Chang-Seok

    2011-07-01

    The static and dynamic characteristics of a wavelength-swept active mode locking (AML) fiber laser are presented in both the time-region and wavelength-region. This paper shows experimentally that the linewidth of a laser spectrum and the bandwidth of the sweeping wavelength are dependent directly on the length and dispersion of the fiber cavity as well as the modulation frequency and sweeping rate under the mode-locking condition. To achieve a narrower linewidth, a longer length and higher dispersion of the fiber cavity as well as a higher order mode locking condition are required simultaneously. For a broader bandwidth, a lower order of the mode locking condition is required using a lower modulation frequency. The dynamic sweeping performance is also analyzed experimentally to determine its applicability to optical coherence tomography imaging. It is shown that the maximum sweeping rate can be improved by the increased free spectral range from the shorter length of the fiber cavity. A reflective semiconductor optical amplifier (RSOA) was used to enhance the modulation and dispersion efficiency. Overall a triangular electrical signal can be used instead of the sinusoidal signal to sweep the lasing wavelength at a high sweeping rate due to the lack of mechanical restrictions in the wavelength sweeping mechanism.

  9. Active media inhomogeneities of gas flow lasers. I - Dust content of solid propellant combustion-driven GDL media. II - Gas flow optics of high power gas lasers

    NASA Astrophysics Data System (ADS)

    Borejsho, Anatolij S.; Leonov, Aleksandr F.; Militsyn, Yurij A.; Moshkov, Vladislav L.; Mal'Kov, Viktor M.

    1993-07-01

    This paper discusses some results obtained during our participation in various special-purpose projects for largescale gas lasers. One of most common problems for these systems is the presence of optical inhomogeneities (including solid particles) in the active media caused by both the processes of the media production and the features of gas flow through nozzle banks and cavities. Various optical methods were used to study the inhomogeneities in continuous wave gas dynamic, chemical, and pulsed photodissociating lasers. Solid propellant sources of working media for the gas dynamic lasers are also considered. Dust content of the laser media is discussed with a special consideration as one of the important problems for this type of gas laser.

  10. Soliton generation from an actively mode-locked fiber laser incorporating an electro-optic fiber modulator.

    PubMed

    Malmström, Mikael; Margulis, Walter; Tarasenko, Oleksandr; Pasiskevicius, Valdas; Laurell, Fredrik

    2012-01-30

    This work demonstrates an actively mode-locked fiber laser operating in soliton regime and employing an all-fiber electro-optic modulator. Nonlinear polarization rotation is utilized for femtosecond pulse generation. Stable operation of the all-fiber ring laser is readily achieved at a fundamental repetition rate of 2.6 MHz and produces 460 fs pulses with a spectral bandwidth of 5.3 nm.

  11. Optical and infrared lasers

    NASA Technical Reports Server (NTRS)

    Javan, A.

    1978-01-01

    Quantum mechanical predictions for the gain of an optically pumped CW FIR laser are presented for cases in which one or both of the pump and FIR transitions are pressure or Doppler broadened. The results are compared to those based on the rate equation model. Some of the quantum mechanical predictions are verified in CH3OH.

  12. High Prf Metal Vapor Laser Active Media For Visual And Optical Monitoring

    NASA Astrophysics Data System (ADS)

    Torgaev, S. N.; Trigub, M. V.; Evtushenko, G. S.; Evtushenko, T. G.

    2016-01-01

    In this paper the feasibility of using metal vapor lasers for visual and optical monitoring of fast processes is discussed. The theoretical calculations consistent with the experimental study have been performed. The possibility of visualizing objects with pulse repetition frequency of the brightness amplifier up to 60 kHz has been demonstrated. The visualization results of the corona discharge are also given.

  13. Optical fiber laser

    SciTech Connect

    Hakimi, F.; Po, H.; Snitzer, E.

    1987-07-14

    An optical fiber laser is described comprising: a gain cavity including a single mode optical fiber of given length having a core with a given index of refraction and a cladding surrounding the core and having an index of refraction lower than that of the core. The core comprises a host glass having incorporated a laser gain material with a fluorescence spectrum having at least one broadband region in which there is at least one peak emission line; filter means optically coupled to one end of the gain cavity and reflective to radiation emitted from the gain material over a predetermined wavelength interval about the peak emission line to provide feedback in the gain cavity; an etalon filter section butt coupled to the remaining end of the gain cavity optical fiber, the etalon filter section comprising a pair of filters spaced apart in parallel by a predetermined length of material transparent to any radiation emitted from the gain cavity. The predetermined length of the transparent material is such that the etalon filter section is no longer than the distance over which the wave train energy from the fiber core remains substantially planar so that the etalon filter section is inside the divergent region to enhance feedback in the gain cavity; and means for pumping energy into the gain cavity to raise the interval energy level such that only a small part of the ion population, corresponding to a predetermined bandwidth about the peak emission line, is raised above laser threshold. The laser emits radiation only over narrow lines over a narrow wavelength interval centered about the peak emission line.

  14. Informal Activities with Lasers, Lights, and Lenses: The Hands-On Optics Project

    NASA Astrophysics Data System (ADS)

    Pompea, S. M.; Sparks, C. E.; Sparks, R. T.

    2005-12-01

    The Hands-On Optics project began as a follow-up to the 2001 NSF planning grant "Optics Education -- A Blueprint for the 21st Century", which described the value of informal science programs in addressing the disconnect between the ubiquity of optics in everyday life and the noticeable absence of optics education in K-12 curricula and in informal science education programs. Key partners in the project are NOAO, SPIE-The International Society for Optical Engineering, and the Optical Society of America (OSA). The informal instructional materials created by the project are distributed through science centers nationwide and through the Mathematics, Engineering, Science Achievement Program (MESA) in a number of states, including Arizona, California, Washington, and Maryland. A key part of the project is the involvement, modeled after Project ASTRO, of optics professionals currently engaged in outreach activities and programs. Optics professionals (termed optics resource volunteers) are teamed with MESA and science center educators in implementing the program. These hands-on, high-interest, standards-connected activities and materials provide 6, three-hour-long optics activity modules that can be used in a variety of informal settings. We will describe the techniques used at NOAO to train educators, parents, and optics professionals who will work with the HOO activities as well as the different approaches needed for different informal education programs, ranging from Saturday programs, after-school programs, and science center programs. NOAO is developing the six modules and associated kits as well as competitions that have broad appeal to 12-year olds. Hands-On Optics: Making an Impact with Light (HOO) is a collaborative NSF-funded four-year informal science education program to excite students about science by actively engaging them in optics activities. NOAO is operated by the Association of Universities for Research in Astronomy (AURA), Inc. under cooperative

  15. Multiphysics modeling of non-linear laser-matter interactions for optically active semiconductors

    NASA Astrophysics Data System (ADS)

    Kraczek, Brent; Kanp, Jaroslaw

    Development of photonic devices for sensors and communications devices has been significantly enhanced by computational modeling. We present a new computational method for modelling laser propagation in optically-active semiconductors within the paraxial wave approximation (PWA). Light propagation is modeled using the Streamline-upwind/Petrov-Galerkin finite element method (FEM). Material response enters through the non-linear polarization, which serves as the right-hand side of the FEM calculation. Maxwell's equations for classical light propagation within the PWA can be written solely in terms of the electric field, producing a wave equation that is a form of the advection-diffusion-reaction equations (ADREs). This allows adaptation of the computational machinery developed for solving ADREs in fluid dynamics to light-propagation modeling. The non-linear polarization is incorporated using a flexible framework to enable the use of multiple methods for carrier-carrier interactions (e.g. relaxation-time-based or Monte Carlo) to enter through the non-linear polarization, as appropriate to the material type. We demonstrate using a simple carrier-carrier model approximating the response of GaN. Supported by ARL Materials Enterprise.

  16. Active linewidth-narrowing of a mid-infrared quantum cascade laser without optical reference.

    PubMed

    Tombez, L; Schilt, S; Hofstetter, D; Südmeyer, T

    2013-12-01

    We report on a technique for frequency noise reduction and linewidth-narrowing of a distributed-feedback mid-IR quantum cascade laser (QCL) that does not involve any optical frequency reference. The voltage fluctuations across the QCL are sensed, amplified and fed back to the temperature of the QCL at a fast rate using a near-IR laser illuminating the top of the QCL chip. A locking bandwidth of 300 kHz and a reduction of the frequency noise power spectral density by a factor of 10 with respect to the free-running laser are achieved. From 2 MHz for the free-running QCL, the linewidth is narrowed below 700 kHz (10 ms observation time).

  17. Study on measurement accuracy of active optics null test systems based on liquid crystal spatial light modulator and laser interferometer

    NASA Astrophysics Data System (ADS)

    Liu, Shijie; Xu, Longbo; Ma, Xiao; Zhang, Zhigang; Zhou, You; Lu, Qi; Bai, Yunbo; Shao, Jianda

    2017-06-01

    A common way to test high-quality aspherical lenses is to use a measurement system based on a set of null corrector and a laser interferometer. The null corrector can either be a combination of spherical lenses or be a computer generated hologram (CGH), which compensates the aspheric wave-front being tested. However, the null optics can't be repeatedly used once the shape of tested optics changes. Alternative active null correctors have been proposed based on dynamic phase modulator devices. A typical dynamic phase modulator is liquid crystal spatial light modulator (LCSLM), which can spatially change the refractive index of the liquid crystal and thus modify the phase of the input wave-front. Even though the measurement method based on LCSLM and laser interferometer has been proposed and demonstrated for optical testing several years ago, it still can't be used in the high quality measurement process due to its limited accuracy. In this paper, we systematically study the factors such as LCSLM structure parameters, encoding error and laser interferometer performance, which significantly affect the measurement accuracy. Some solutions will be proposed in order to improve the measurement accuracy based on LCSLM and laser interferometer.

  18. Interferometric ring lasers and optical devices

    DOEpatents

    Hohimer, J.P.; Craft, D.C.

    1995-03-14

    Two ring diode lasers are optically coupled together to produce tunable, stable output through a Y-junction output coupler which may also be a laser diode or can be an active waveguide. These devices demonstrate a sharp peak in light output with an excellent side-mode-rejection ratio. The rings can also be made of passive or active waveguide material. With additional rings the device is a tunable optical multiplexer/demultiplexer. 11 figs.

  19. Interferometric ring lasers and optical devices

    DOEpatents

    Hohimer, John P.; Craft, David C.

    1995-01-01

    Two ring diode lasers are optically coupled together to produce tunable, stable output through a Y-junction output coupler which may also be a laser diode or can be an active waveguide. These devices demonstrate a sharp peak in light output with an excellent side-mode-rejection ratio. The rings can also be made of passive or active waveguide material. With additional rings the device is a tunable optical multiplexer/demultiplexer.

  20. Optics and lasers: A compilation

    NASA Technical Reports Server (NTRS)

    1976-01-01

    A number of innovative devices and techniques in optics and related fields were presented. The following areas were covered: advances in laser and holography technology, articles on spectroscopy and general optics, new information in the area of photography.

  1. CONTROL OF LASER RADIATION PARAMETERS: Study of the spectral width of intermode beats and optical spectrum of an actively mode-locked three-mirror semiconductor laser

    NASA Astrophysics Data System (ADS)

    Zakharyash, Valerii F.; Kashirsky, Aleksandr V.; Klementyev, Vasilii M.; Kuznetsov, Sergei A.; Pivtsov, V. S.

    2005-09-01

    Various oscillation regimes of an actively mode-locked semiconductor laser are studied experimentally. Two types of regimes are found in which the minimal spectral width (~3.5 kHz) of intermode beats is achieved. The width of the optical spectrum of modes is studied as a function of their locking and the feedback coefficients. The maximum width of the spectrum is ~3.7 THz.

  2. Space simulators for laser optics

    NASA Technical Reports Server (NTRS)

    Gardner, Frank H.

    1988-01-01

    Different approaches that are being utilized to test laser optical systems are described. One of the most crucial areas in the testing phase is the stability of the laser optics mounted inside the space simulator. The thermal vacuum system, the refrigeration system, and the space simulator are discussed.

  3. High precision laser photometer for laser optics

    NASA Astrophysics Data System (ADS)

    Zhao, Yuan'an; Hu, Guohang; Cao, Zhen; Liu, Shijie; Zhu, Meiping; Shao, Jianda

    2017-06-01

    Development of laser systems requires optical components with high performance, and a high-precision double-beam laser photometer was designed and established to measure the optical performance at 1064nm. Double beam design and lock-in technique was applied to decrease the impact of light energy instability and electric noise. Pairs of samples were placed symmetrically to eliminate beam displacement, and laser scattering imaging technique was applied to determine the influence of surface defect on the optical performance. Based on the above techniques, transmittance and reflection of pairs of optics were obtained, and the measurement precision was improved to 0.06%. Different types of optical loss, such as total loss, volume loss, residual reflection and surface scattering loss, were obtained from the transmittance and reflection measurement of samples with different thickness. Comparison of optical performance of the test points with and without surface defects, the influence of surface defects on optical performance was determined. The optical performance of Nd-glass at 1064nm were measured as an example. Different types of optical loss and the influence of surface defects on the optical loss was determined.

  4. Acousto-optic laser optical feedback imaging.

    PubMed

    Jacquin, O; Glastre, W; Lacot, E; Hugon, O; Guillet de Chatellus, H; Ramaz, F

    2012-07-01

    We present a photon noise and diffraction-limited imaging method combining an imaging laser and ultrasonic waves. The laser optical feedback imaging (LOFI) technique is an ultrasensitive imaging method for imaging objects through or embedded within a scattering medium. However, LOFI performances are dramatically limited by parasitic optical feedback occurring in the experimental setup. In this Letter, we have tagged the ballistic photons by an acousto-optic effect in order to filter the parasitic feedback effect and to reach the theoretical and ultimate sensitivity of the LOFI technique. We present the principle and the experimental setup of the acousto-optic laser optical feedback imaging technique, and we demonstrate the suppression of the parasitic feedback.

  5. Optical characterization of InGaN/GaN quantum well active region of green laser diodes

    NASA Astrophysics Data System (ADS)

    Tian, Aiqin; Liu, Jianping; Zhang, Liqun; Ikeda, Masao; Fan, Xiaowang; Zhang, Shuming; Li, Deyao; Zhang, Feng; Wen, Pengyan; Cheng, Yang; Yang, Hui

    2017-01-01

    We performed the optical characterization of InGaN/GaN quantum well (QW) active regions of green laser diodes (LDs) with different threshold current densities by temperature-dependent photoluminescence (PL) analysis. The internal quantum efficiency (IQE) was evaluated to be 39 and 59% for green LDs with threshold current densities of 8.50 and 1.85 kA cm-2, respectively. Additional nonradiative recombination centers with an activation energy of 10 meV were found in the sample with the lower IQE, which is attributed to defects located at the interface of InGaN/GaN QWs.

  6. Laser optical displacement system

    NASA Astrophysics Data System (ADS)

    Starritt, Larry W.; Matthews, Larryl K.

    1995-04-01

    The current quality of our nations bridges is on a decline. There are roughly half a million highway bridges in the United States and out of the half a million more than 200,000 are deficient. With catastrophic failure of bridges causing the loss of life and property, the need for bridge inspection and maintenance is evident. When the Silver Bridge that crossed the Ohio River collapsed in December 1967, 46 people were killed. The failure to prevent the disaster was attributed to the poor inspection techniques used by the bridge inspectors. Current inspection techniques depend on humans being able to recognize structural imperfections without the aid of instrumentation. The Federal-Aid Highway Act of 1968 mandated both national bridge inspection standards and training for bridge inspectors. This act has encouraged the development of instruments that would allow inspectors to perform more complete inspections of bridges. To improve the quality of inspection and data, there is a great need for proven methods and instruments used to acquire data. The Laser Optical Displacement System (L.O.D.S.) developed at New Mexico State University by the Optical and Materials Science Lab is such a device. The L.O.D.S. has been tested and proven in both laboratory situations and in the field. This paper describes some of the methods that are now being used to measure deflections in bridges. Then, a description of the development and application of the L.O.D.S. unit is given.

  7. Laser peening with fiber optic delivery

    DOEpatents

    Friedman, Herbert W.; Ault, Earl R.; Scheibner, Karl F.

    2004-11-16

    A system for processing a workpiece using a laser. The laser produces at least one laser pulse. A laser processing unit is used to process the workpiece using the at least one laser pulse. A fiber optic cable is used for transmitting the at least one laser pulse from the laser to the laser processing unit.

  8. Optically biased laser gyro

    SciTech Connect

    Anderson, D.Z.; Chow, W.W.; Scully, M.O.; Sanders, V.E.

    1980-10-01

    We describe a four-mode ring laser that exhibits none of the mode-locking characteristics that plague laser gyros. This laser is characterized by a bias that changes sign with a change in the direction of rotation and prevents the counterpropagating modes from locking. A theoretical analysis explaining the experimental results is outlined.

  9. Wavelength-tunable 10 GHz actively harmonic mode-locked fiber laser based on semiconductor optical amplifier

    NASA Astrophysics Data System (ADS)

    Mao, Yan; Tong, Xinglin; Wang, Zhiqiang; Zhan, Li; Hu, Pan; Chen, Liang

    2015-12-01

    We demonstrate a widely wavelength-tunable actively mode-locked fiber laser based on semiconductor optical amplifier. Beneficiating from the actively mode-locking operation and the wavelength-tunable characteristics of a Fabry-Perot filter, different harmonic mode-locking orders, from the fundamental mode-locking order (18.9 MHz) to the 520th order (9.832 GHz), can be easily achieved. The spectral bandwidth corresponding to the fundamental repetition rate is 0.12 nm with the pulse duration of 9.8 ns, leading to the TBP value of 146, which is about 460 times the transform-limited value for soliton pulse. The highest repetition rate of the mode-locked pulses we obtained is 9.832 GHz, with a signal-to-noise ratio up to 50 dB. The theoretical transform-limited pulse duration is 21 ps. Meanwhile, the central wavelength can be continuously tuned over 43.4 nm range (1522.8-1566.2 nm). The higher repetition rate and the widely tuning wavelength range make the fiber laser to own great potential and promising prospects in areas such as optical communication and photonic analog-to-digital conversion (ADC).

  10. Lasers and Optics

    DTIC Science & Technology

    2013-03-05

    Develop in-house Quantum Cascade Laser technology at 4-5µm wavelength range – Generate high power from broad-area QCL devices – Explore novel novel...schemes to produce high brightness – Advance beam-combining strategies in QCLs – Transition high brightness QCL technology to AF and DoD users...DISTRIBUTION A: Approved for public release; distribution is unlimited. 22 • Quantum Cascade Laser ( QCL ) technology can produce compact laser sources

  11. Optically pumped rare-gas lasers

    SciTech Connect

    Mikheyev, P A

    2015-08-31

    The modern state of the research of a new promising optically pumped laser system with an active medium formed by metastable rare-gas atoms is briefly reviewed. The kinetics of these media is similar to that of laser media based on alkali metal vapour; however, the gas medium is inert. Metastable atoms can be produced in an electric discharge. As in alkali lasers, the specific laser power output under atmospheric pressure can be several hundreds of watts per 1 cm{sup 3}. The lasing wavelengths lie in the near-IR range and fall in the transparency window of the terrestrial atmosphere. This new concept makes it possible to develop a closed-cycle cw laser with megawatt power levels and high beam quality. (lasers)

  12. Optics assembly for high power laser tools

    DOEpatents

    Fraze, Jason D.; Faircloth, Brian O.; Zediker, Mark S.

    2016-06-07

    There is provided a high power laser rotational optical assembly for use with, or in high power laser tools for performing high power laser operations. In particular, the optical assembly finds applications in performing high power laser operations on, and in, remote and difficult to access locations. The optical assembly has rotational seals and bearing configurations to avoid contamination of the laser beam path and optics.

  13. Initial alignment method for free space optics laser beam

    NASA Astrophysics Data System (ADS)

    Shimada, Yuta; Tashiro, Yuki; Izumi, Kiyotaka; Yoshida, Koichi; Tsujimura, Takeshi

    2016-08-01

    The authors have newly proposed and constructed an active free space optics transmission system. It is equipped with a motor driven laser emitting mechanism and positioning photodiodes, and it transmits a collimated thin laser beam and accurately steers the laser beam direction. It is necessary to introduce the laser beam within sensible range of the receiver in advance of laser beam tracking control. This paper studies an estimation method of laser reaching point for initial laser beam alignment. Distributed photodiodes detect laser luminescence at respective position, and the optical axis of laser beam is analytically presumed based on the Gaussian beam optics. Computer simulation evaluates the accuracy of the proposed estimation methods, and results disclose that the methods help us to guide the laser beam to a distant receiver.

  14. Heterogeneously integrated microdisk lasers for optical interconnects and optical logic

    NASA Astrophysics Data System (ADS)

    Mechet, Pauline; Liu, Liu; Kumar, Rajesh; Huybrechts, Koen; Spuesens, Thijs; Roelkens, Günther; Geluk, Erik-Jan; de Vries, Tjibbe; Regreny, Philippe; Van Thourhout, Dries; Baets, Roel; Morthier, Geert

    2011-03-01

    Optical interconnect and optical packet switching systems could take advantage of small footprint, low power lasers and optical logic elements. Microdisk lasers, with a diameter below 10μm and fabricated in InP membranes with a high index contrast, offer this possibility at the telecom wavelengths. The lasers are fabricated using heterogeneous integration of InP membranes on silicon-on-insulator (SOI) passive waveguide circuits, which allows to combine the active elements with compact, high-index contrast passive elements. The lasing mode in such microdisk lasers is a whispering gallery mode, which can be either in the clockwise (CW) or counter clockwise direction (CCW) or in both. The coupling to the SOI wire waveguides is through evanescent coupling. Predefined, unidirectional operation can be achieved by terminating the SOI wires at one end with Bragg gratings. For all-optical flip-flops, the laser operation must be switchable between CW and CCW, using short optical pulses. Unidirectional operation in either direction is only possible if the coupling between CW and CCW direction is very small, requiring small sidewall surface roughness, and if the gain suppression is sufficiently large, requiring large internal power levels. All-optical flip-flops based on microdisk lasers with diameter of 7.5μm have been demonstrated. They operate with a CW power consumption of a few mW and switch in 60ps with switching energies as low as 1.8fJ. Operation as all-optical gate has also been demonstrated. The surface roughness is limited through optimized etching of the disks and the large internal power is obtained through good heat sink.

  15. Functional evaluation of hemodynamic response during neural activation using optical microangiography integrated with dual-wavelength laser speckle imaging

    PubMed Central

    Qin, Jia; Shi, Lei; Wang, Hequn; Reif, Roberto; Wang, Ruikang K.

    2014-01-01

    Abstract. Evaluation of spatiotemporal hemodynamic and metabolic responses during neural activation is crucial in studying brain function. We explore the use of a noninvasive multifunctional optical imaging system to measure these responses in a mouse brain upon electrically stimulated neural activation, with the cranium left intact. The system is developed by integrating an optical microangiography (OMAG) imaging system with a dual-wavelength laser speckle imaging (DW-LSI) system. The DW-LSI, running at an image acquisition speed of ∼100  Hz, is used to extract the large-scale two-dimensional map, revealing the localized response of blood flow, hemoglobin concentration, and metabolic rate of oxygen change. Guided by DW-LSI, the OMAG is, however, used to image the response of individual blood vessels with its unique depth-resolved capability. We show that the integrated system is capable of investigating neural activation, thus is potentially valuable in the preclinical study of the mechanism of neurovascular coupling. PMID:24549439

  16. Long-cavity all-fiber ring laser actively mode locked with an in-fiber bandpass acousto-optic modulator.

    PubMed

    Cuadrado-Laborde, C; Bello-Jiménez, M; Díez, A; Cruz, J L; Andrés, M V

    2014-01-01

    We demonstrate low-frequency active mode locking of an erbium-doped all-fiber ring laser. As the mode locker, we used a new in-fiber bandpass acousto-optic modulator showing 74% modulation depth, 3.7 dB power insertion losses, 4.5 nm of optical bandwidth, and 20 dB of nonresonant light suppression. The laser generates 330 ps mode-locked pulses over a 10 ns pedestal, at a 1.538 MHz frequency, with 130 mW of pump power.

  17. Optical pulse generation using fiber lasers and integrated optics

    SciTech Connect

    Wilcox, R.B.; Browning, D.F.; Burkhart, S.C.; VanWonterghem, B.W.

    1995-03-27

    We have demonstrated an optical pulse forming system using fiber and integrated optics, and have designed a multiple-output system for a proposed fusion laser facility. Our approach is an advancement over previous designs for fusion lasers, and an unusual application of fiber lasers and integrated optics.

  18. Coherent combining of fiber-laser-pumped frequency converters using all fiber electro-optic modulator for active phase control

    NASA Astrophysics Data System (ADS)

    Bourdon, P.; Durécu, A.; Canat, G.; Le Gouët, J.; Goular, D.; Lombard, L.

    2015-03-01

    Coherent beam combining (CBC) by active phase control could be useful for power scaling fiber-laser-pumped optical frequency converters like OPOs. However, a phase modulator operating at the frequency-converted wavelength is needed, which is non standard component. Fortunately, nonlinear conversion processes rely on a phase-matching condition correlating, not only the wave vectors of the coupled waves, but also their phases. This paper demonstrates that, using this phase correlation for indirect control of the phase, coherent combining of optical frequency converters is feasible using standard all-fibered electro-optic modulators. For the sake of demonstration, this new technique is experimentally applied twice for continuous wave second-harmonic-generator (SHG) combination: i) combining 2 SHG of 1.55-μm erbium-doped fiber amplifiers in PPLN crystals generating 775-nm beams; ii) combining 2 SHG of 1.064-μm ytterbium-doped fiber amplifiers in LBO crystals generating 532-nm beams. Excellent CBC efficiency is achieved on the harmonic waves in both these experiments, with λ/20 and λ/30 residual phase error respectively. In the second experiment, I/Q phase detection is added on fundamental and harmonic waves to measure their phase variations simultaneously. These measurements confirm the theoretical expectations and formulae of correlation between the phases of the fundamental and harmonic waves. Unexpectedly, in both experiments, when harmonic waves are phase-locked, a residual phase difference remains between the fundamen tal waves. Measurements of the spectrum of these residual phase differences locate them above 50 Hz, revealing that they most probably originate in fast-varying optical path differences induced by turbulence and acoustic-waves on the experimental breadboard.

  19. Electro-Optic Diffraction Grating Tuned Laser.

    DTIC Science & Technology

    The patent concerns an electro - optic diffraction grating tuned laser comprising a laser medium, output mirror, retro-reflective grating and an electro - optic diffraction grating beam deflector positioned between the laser medium and the reflective diffraction grating. An optional angle multiplier may be used between the electro - optic diffraction grating and the reflective grating.

  20. Optical resonator and laser applications

    NASA Technical Reports Server (NTRS)

    Taghavi-Larigani, Shervin (Inventor); Vanzyl, Jakob J. (Inventor); Yariv, Amnon (Inventor)

    2006-01-01

    The invention discloses a semi-ring Fabry-Perot (SRFP) optical resonator structure comprising a medium including an edge forming a reflective facet and a waveguide within the medium, the waveguide having opposing ends formed by the reflective facet. The performance of the SRFP resonator can be further enhanced by including a Mach-Zehnder interferometer in the waveguide on one side of the gain medium. The optical resonator can be employed in a variety of optical devices. Laser structures using at least one SRFP resonator are disclosed where the resonators are disposed on opposite sides of a gain medium. Other laser structures employing one or more resonators on one side of a gain region are also disclosed.

  1. Fiber optic and laser sensors VII

    SciTech Connect

    Udd, E.; De Paula, R.P.

    1989-01-01

    This book contains articles on fiber optic and laser sensors. Included are these topics: Fiber optic sensor development at universities, Fiber optic sensing techniques, Magnetics, and Acoustics and pressure sensors.

  2. Integration of active optical components

    NASA Astrophysics Data System (ADS)

    Wipiejewski, Torsten; Akulova, Yuliya A.; Fish, Gregory A.; Schow, Clint L.; Koh, Ping; Karim, Adil; Nakagawa, Shigeru; Dahl, Anders; Kozodoy, Peter; Matson, Alex; Short, Bradley W.; Turner, Chuck M.; Penniman, Steven; Larson, Michael C.; Coldren, Christopher W.; Coldren, Larry A.

    2003-06-01

    Integration of active optical components typically serves five goals: enhanced performance, smaller space, lower power dissipation, higher reliability, and lower cost. We are manufacturing widely tunable laser diodes with an integrated high speed electro absorption modulator for metro and all-optical switching applications. The monolithic integration combines the functions of high power laser light generation, wavelength tuning over the entire C-band, and high speed signal modulation in a single chip. The laser section of the chip contains two sampled grating DBRs with a gain and a phase section between them. The emission wavelength is tuned by current injection into the waveguide layers of the DBR and phase sections. The laser light passes through an integrated optical amplifier before reaching the modulator section on the chip. The amplifier boosts the cw output power of the laser and provides a convenient way of power leveling. The modulator is based on the Franz-Keldysh effect for a wide band of operation. The common waveguide through all sections minimizes optical coupling losses. The packaging of the monolithically integrated chip is much simpler compared to a discrete or hybrid solution using a laser chip, an SOA, and an external modulator. Since only one optical fiber coupling is required, the overall packaging cost of the transmitter module is largely reduced. Error free transmission at 2.5Gbit/s over 200km of standard single mode fiber is obtained with less than 1dB of dispersion penalty.

  3. Output optics for laser velocimeters

    NASA Technical Reports Server (NTRS)

    Lynch, Dana H. (Inventor); Gunter, William D. (Inventor); Mcalister, Kenneth W. (Inventor)

    1993-01-01

    Space savings are effected in the optical output system of a laser velocimeter. The output system is comprised of pairs of optical fibers having output ends from which a beam of laser light emerges, a transfer lens for each light beam, and at least one final (LV) lens for receiving the light passing through the transfer lenses and for focussing that light at a common crossing point or area. In order to closely couple the transfer lenses to the final lens, each transfer lens is positioned relative to the final lens receiving light therefrom such that the output waist of the corresponding beam received by the final lens from the transfer lens is a virtual waist located before the transfer lens.

  4. Optical materials for space based laser systems

    NASA Technical Reports Server (NTRS)

    Buoncristiani, A. M.; Armagan, G.; Byvik, C. E.; Albin, S.

    1989-01-01

    The design features and performance characteristics of a sensitized holmium laser applicable to differential lidar and Doppler windshear measurements are presented, giving attention to the optimal choice of sensitizing/activating dopant ions. This development of a 2-micron region eye-safe laser, where holmium is sensitized by either hulium or erbium, has called for interionic energy transfer processes whose rate will not result in gain-switched pulses that are excessively long for atmospheric lidar and Doppler windshear detection. The application of diamond films for optical component hardening is noted.

  5. Optical materials for space based laser systems

    NASA Technical Reports Server (NTRS)

    Buoncristiani, A. M.; Armagan, G.; Byvik, C. E.; Albin, S.

    1989-01-01

    The design features and performance characteristics of a sensitized holmium laser applicable to differential lidar and Doppler windshear measurements are presented, giving attention to the optimal choice of sensitizing/activating dopant ions. This development of a 2-micron region eye-safe laser, where holmium is sensitized by either hulium or erbium, has called for interionic energy transfer processes whose rate will not result in gain-switched pulses that are excessively long for atmospheric lidar and Doppler windshear detection. The application of diamond films for optical component hardening is noted.

  6. Adaptive optics for laser space debris removal

    NASA Astrophysics Data System (ADS)

    Bennet, Francis; Conan, Rodolphe; D'Orgeville, Celine; Dawson, Murray; Paulin, Nicolas; Price, Ian; Rigaut, Francois; Ritchie, Ian; Smith, Craig; Uhlendorf, Kristina

    2012-07-01

    Space debris in low Earth orbit below 1500km is becoming an increasing threat to satellites and spacecrafts. Radar and laser tracking are currently used to monitor the orbits of thousands of space debris and active satellites are able to use this information to manoeuvre out of the way of a predicted collision. However, many satellites are not able to manoeuvre and debris-on debris collisions are becoming a signicant contributor to the growing space debris population. The removal of the space debris from orbit is the preferred and more denitive solution. Space debris removal may be achieved through laser ablation, whereby a high power laser corrected with an adaptive optics system could, in theory, allow ablation of the debris surface and so impart a remote thrust on the targeted object. The goal of this is to avoid collisions between space debris to prevent an exponential increase in the number of space debris objects. We are developing an experiment to demonstrate the feasibility of laser ablation for space debris removal. This laser ablation demonstrator utilises a pulsed sodium laser to probe the atmosphere ahead of the space debris and the sun re ection of the space debris is used to provide atmospheric tip{tilt information. A deformable mirror is then shaped to correct an infrared laser beam on the uplink path to the debris. We present here the design and the expected performance of the system.

  7. 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.

  8. Airborne Visible Laser Optical Communications Program (AVLOC)

    NASA Technical Reports Server (NTRS)

    Ward, J. H.

    1975-01-01

    The design, development, and operation of airborne and ground-based laser communications and laser radar hardware is described in support of the Airborne Visible Laser Optical Communication program. The major emphasis is placed on the development of a highly flexible test bed for the evaluation of laser communications systems techniques and components in an operational environment.

  9. Magnetic optical activity in intense laser fields. I - Self-rotation and Verdet constant

    NASA Technical Reports Server (NTRS)

    Giraud-Cotton, S.; Kaftandjian, V. P.; Klein, L.

    1985-01-01

    The paper is concerned with the Faraday rotation and circular dichroism of dilute gases in longitudinal magnetic fields subject to strong radiation fields. In particular, magnetic fields are considered which produce Zeeman shifts much smaller than inverse collision times but which may be greater or smaller then the multipole relaxation times. Doppler broadening is considered, and explicit expressions are given for dipole transitions in a two-level system with arbitrary angular momentum for strong and weak magnetic fields. The same system is then studied as a function of the external magnetic-field strength with a fixed laser frequency. It is shown that this experimental arrangement, referred to as forward scattering, has certain advantages that are not present in the more usual magnetic rotation spectroscopy.

  10. Active Q-switching in an erbium-doped fiber laser using an ultrafast silicon-based variable optical attenuator.

    PubMed

    Chang, You Min; Lee, Junsu; Jhon, Young Min; Lee, Ju Han

    2011-12-19

    Presented herein is the use of an ultrafast Si-based variable optical attenuator (VOA) as a Q-switch for rare earth-doped fiber lasers. The ultrafast VOA is based on a forward-biased p-i-n diode integrated with a ridge waveguide, which was originally designed and optimized for WDM channel power equalization in optical communication systems. By incorporating a Si-based VOA with a transient time of ~410 ns into an erbium-doped fiber-based Fabry-Perot cavity it has been shown that stable Q-switched pulses possessing a temporal width of less than ~86 ns can be readily obtained at a repetition rate of up to ~1 MHz. The laser's peak power of ~38 W is shown to be obtainable at 20 kHz with a slope efficiency of ~21%.

  11. Semiconductor ring lasers as optical neurons

    NASA Astrophysics Data System (ADS)

    Coomans, W.; Gelens, L.; Mashal, L.; Beri, S.; Van der Sande, G.; Danckaert, J.; Verschaffelt, G.

    2012-06-01

    Semiconductor Ring Lasers (SRLs) are a modern class of semiconductor lasers whose active cavity is characterized by a circular geometry. This enables the laser to support two counterpropagating modes, referred to as the clockwise (CW) and the counterclockwise (CCW) mode. Semiconductor ring lasers have been shown to have a regime of operation in which they are excitable, when the linear coupling between the counterpropagating modes is asymmetric. This can be achieved by increasing the reflection of, for example, the CW mode into the CCW mode. This will stabilize lasing in the CCW mode. In the excitable regime, the SRL will fire optical pulses (spikes) in the CW mode as a response to noise perturbations. In this contribution we experimentally and theoretically characterize these spikes. Our experiments reveal a statistical distribution of the characteristics of the optical pulses that is not observed in regular excitable systems. In particular, an inverse correlation exists between the pulse amplitude and duration. Numerical simulations and an interpretation in an asymptotic phase space confirm and explain these experimentally observed pulse characteristics [L. Gelens et al., Phys. Rev. A 82 063841, 2010]. We will also theoretically consider asymmetric SRLs coupled through a single bus waveguide. This is a first step towards an integrated optical neural network using semiconductor ring lasers as building blocks. We will show that for weak coupling, excitatory excursions still persist due to the similar phase space structure. Moreover, the coupled SRLs can excite pulses in each other and can thus function as communicating neurons [W. Coomans et al., Phys. Rev. E 84 036209, 2011]. This type of neural network can be fully integrated on chip and does not suffer from the drawback of needing extra-cavity measures, such as optical injection or saturable absorbers.

  12. Compact active mirror laser (CAMIL)

    NASA Astrophysics Data System (ADS)

    Vetrovec, John

    2002-03-01

    This work presents concept and scaling considerations for a solid-state laser with a gain medium disk operating in the active mirror mode. The disk is of composite construction formed by bonding undoped optical medium to the peripheral edges of a gain medium disk. Pump diode arrays are placed around the perimeter of the composite disk and pump light is injected into the undoped edge. With proper choice of lasant doping, diode placement and diode divergence, a uniform laser gain can be achieved across large portions of the disk. To mitigate thermal deformations, the gain medium disk is pressure-clamped to a rigid, cooled substrate. Effective reduction of thermo-optical distortions makes this laser suitable for operation at high-average power.

  13. ELEMENTS OF LASER SETUPS: Characteristics of Cornu depolarisers made from quartz and paratellurite optically active crystals

    NASA Astrophysics Data System (ADS)

    Bagan, V. A.; Davydov, B. L.; Samartsev, I. E.

    2009-01-01

    Cornu depolarisers made from quartz and paratellurite crystals have been studied. Numerical calculations and experimental data demonstrate that such depolarisers make it possible to significantly alleviate the major drawback to birefringent wedge depolarisers: the strong dependence of the polarisation of the output beam on the input polarisation orientation. We have examined the polarisation extinction ratio in the depolarisers as a function of the rotatory power of the crystals, depolariser length, beam diameter, and power distribution across the beam, and have determined the angle between the circularly polarised output beams in the far field. Data on the optical rotatory power of quartz and paratellurite crystals have been systematized, and the results have been used to derive dispersion formulas for these materials in the visible and near-IR spectral regions.

  14. Utilizing laser interference lithography to fabricate hierarchical optical active nanostructures inspired by the blue Morpho butterfly

    NASA Astrophysics Data System (ADS)

    Siddique, Radwanul H.; Faisal, Abrar; Hünig, Ruben; Bartels, Carolin; Wacker, Irene; Lemmer, Uli; Hoelscher, Hendrik

    2014-09-01

    The famous non-iridescent blue of the Morpho butter by is caused by a `Christmas tree' like nanostructure which is a challenge for common fabrication techniques. Here, we introduce a method to fabricate this complex morphology utilizing dual beam interference lithography. We add a reflective coating below the photoresist to create a second interference pattern in vertical direction by exploiting the back reflection from the substrate. This vertical pattern exposes the lamella structure into the photosensitive polymer while the horizontal interference pattern determines the distance of the ridges. The photosensitive polymer is chosen accordingly to create the Christmas tree' like tapered shape. The resulting artificial Morpho replica shows brilliant non-iridescent blue up to an incident angle of 40. Its optical properties are close to the original Morpho structure because the refractive index of the polymer is close to chitin. Moreover, the biomimetic surface is water repellent with a contact angle of 110.

  15. Precision optical metrology without lasers

    NASA Astrophysics Data System (ADS)

    Bergmann, Ralf B.; Burke, Jan; Falldorf, Claas

    2015-07-01

    Optical metrology is a key technique when it comes to precise and fast measurement with a resolution down to the micrometer or even nanometer regime. The choice of a particular optical metrology technique and the quality of results depends on sample parameters such as size, geometry and surface roughness as well as user requirements such as resolution, measurement time and robustness. Interferometry-based techniques are well known for their low measurement uncertainty in the nm range, but usually require careful isolation against vibration and a laser source that often needs shielding for reasons of eye-safety. In this paper, we concentrate on high precision optical metrology without lasers by using the gradient based measurement technique of deflectometry and the finite difference based technique of shear interferometry. Careful calibration of deflectometry systems allows one to investigate virtually all kinds of reflecting surfaces including aspheres or free-form surfaces with measurement uncertainties below the μm level. Computational Shear Interferometry (CoSI) allows us to combine interferometric accuracy and the possibility to use cheap and eye-safe low-brilliance light sources such as e.g. fiber coupled LEDs or even liquid crystal displays. We use CoSI e.g. for quantitative phase contrast imaging in microscopy. We highlight the advantages of both methods, discuss their transfer functions and present results on the precision of both techniques.

  16. Optical Solid State Cooling within a Laser

    NASA Astrophysics Data System (ADS)

    Stone, M.; Heeg, B.; Khizhnyak, A.; DeBarber, P. A.

    2004-06-01

    Recent demonstrations of optical solid state cooling by anti-Stokes luminescence has yielded temperatures of 236 K, while it has been predicted that cooling efficiencies of the order of 1% are obtainable for temperatures as low as 40 to 50 K for some materials. In this paper, we will discuss a design of an optical cooling device based on the idea of locating the active cooling element inside a laser resonator. The inherent multi-passing of radiation within a laser cavity allows efficient pumping of the cooling medium. Results of a low power prototype version of the device are discussed and a method for optimizing the cooling efficiencies with this approach is presented.

  17. Optical isolator for semiconductor lasers.

    PubMed

    Kuwahara, H

    1980-01-15

    An optical isolator for semiconductor lasers, consisting of a polarizer and a quarterwave plate, was investigated experimentally. It was assembled in a compact laser-to-fiber coupling module. Experiment showed forward loss of 1.15 dB, backward loss of 24.8 dB, and rotative tolerance of 2.4 deg for 1 dB down. The length of the module is 43.2 mm. The coupling efficiency to a graded-index multimode fiber is 37.5%. The extinction ratio is improved by 6.75 dB. The suppression effect on the influence of reflected light was investigated, using the assembled module.

  18. Actively Q-switched, thulium-holmium-codoped fiber laser incorporating a silicon-based, variable-optical-attenuator-based Q switch.

    PubMed

    Jung, Minwan; Han Lee, Ju

    2013-04-20

    An actively Q-switched thulium-holmium-codoped fiber laser incorporating an Si-based variable optical attenuator (VOA) is experimentally demonstrated. It has been shown that an Si-based VOA with a response time of hundreds of nanoseconds can be used as a cost-effective 2 μm Q switch due to its extremely wide operating bandwidth from 1.5 to 2 μm, and low electrical power consumption. In our study, the laser's slope efficiency was measured to be ~17% at an operating wavelength of 1.89 μm. The repetition rate tuning range was from 20 to 80 kHz, which was limited by the optical damage threshold and the response time. The minimum temporal pulsewidth was measured to be ~184 ns at a modulation frequency of 20 kHz, and the corresponding maximum peak power was ~10 W.

  19. Optically (solar) pumped oxygen-iodine lasers

    NASA Astrophysics Data System (ADS)

    Danilov, O. B.; Zhevlakov, A. P.; Yur'ev, M. S.

    2014-07-01

    We present the results of theoretical and experimental studies demonstrating the possibility of developing an oxygen-iodine laser (OIL) with direct optical pumping of molecular oxygen involving inter-molecular interaction with charge transfer from donor molecule (buffer gas) to acceptor molecule (oxygen). This interaction lifts degeneracy of the lower energy states of molecular oxygen and increases its absorption cross section in the visible spectral region and the UV Herzberg band, where high quantum yield of singlet oxygen is achieved (QY ˜ 1 and QY ˜ 2, respectively) at the same time. A pulse-periodic optical pump sources with pulse energy of ˜50 kJ, pulse duration of ˜25 μs, and repetition rate of ˜10 Hz, which are synchronized with the mechanism of singlet oxygen generation, are developed. This allows implementation of a pulse-periodic oxygen-iodine laser with an efficiency of ˜25%, optical efficiency of ˜40%, and parameter L/ T ˜ 1/1.5, where T is the thermal energy released in the laser active medium upon generation of energy L. It is demonstrated that, under direct solar pumping of molecular oxygen, the efficiency parameter of the OIL can reach L/ T ˜ 1/0.8 in a wide range of scaling factors.

  20. Fiber laser coupled optical spark delivery system

    DOEpatents

    Yalin, Azer; Willson, Bryan; Defoort, Morgan; Joshi, Sachin; Reynolds, Adam

    2008-03-04

    A spark delivery system for generating a spark using a laser beam is provided, and includes a laser light source and a laser delivery assembly. The laser delivery assembly includes a hollow fiber and a launch assembly comprising launch focusing optics to input the laser beam in the hollow fiber. The laser delivery assembly further includes exit focusing optics that demagnify an exit beam of laser light from the hollow fiber, thereby increasing the intensity of the laser beam and creating a spark. Other embodiments use a fiber laser to generate a spark. Embodiments of the present invention may be used to create a spark in an engine. Yet other embodiments include collecting light from the spark or a flame resulting from the spark and conveying the light for diagnostics. Methods of using the spark delivery systems and diagnostic systems are provided.

  1. A study of optical design and optimization of laser optics

    NASA Astrophysics Data System (ADS)

    Tsai, C.-M.; Fang, Yi-Chin

    2013-09-01

    This paper propose a study of optical design of laser beam shaping optics with aspheric surface and application of genetic algorithm (GA) to find the optimal results. Nd: YAG 355 waveband laser flat-top optical system, this study employed the Light tools LDS (least damped square) and the GA of artificial intelligence optimization method to determine the optimal aspheric coefficient and obtain the optimal solution. This study applied the aspheric lens with GA for the flattening of laser beams using collimated laser beam light, aspheric lenses in order to achieve best results.

  2. Fiber optic applications for laser polarized targets

    SciTech Connect

    Cummings, W.J.; Kowalczyk, R.S.

    1997-10-01

    For the past two years, the laser polarized target group at Argonne has been used multi-mode fiber optic patch cords for a variety of applications. In this paper, the authors describe the design for transporting high power laser beams with optical fibers currently in use at IUCF.

  3. Integrated optics approach for advanced semiconductor lasers

    NASA Astrophysics Data System (ADS)

    Suematsu, Yasuharu; Arai, Shigehisa

    1987-11-01

    Recent advances in the field of semiconductor integrated optics are reviewed from the point of view of monolithic integration of semiconductor lasers and other optical components and/or devices. Emphasis is placed on dynamic-single-mode (DSM) lasers, such as DFB and DBR lasers, intended for highly stable single-wavelength light sources for such monolithic integration. The realization of high-performance DSM lasers and the fabrication techniques of monolithically integrated optical devices and circuits are briefly reviewed. A variety of potential applications is discussed.

  4. Stark effect in optically pumped molecular submillimeter lasers

    NASA Astrophysics Data System (ADS)

    Rak, V. G.; Dyubko, S. F.

    1980-06-01

    A theoretical analysis is made of the effects which take place in optically pumped lasers whose active medium is subjected to a dc electric Geld. The possibilities are discussed of tuning the frequency and modulating the intensity of the radiation emitted by a laser. The gain characteristics of an active medium in an electric field are calculated for a CH3F laser operating on a wavelength of 496 μ. It is shown that the frequency tuning limits of the output radiation of such a laser can reach 3 GHz, if the active medium allows electric fields of up to 30 kV/cm to be applied.

  5. Active optical zoom system

    DOEpatents

    Wick, David V.

    2005-12-20

    An active optical zoom system changes the magnification (or effective focal length) of an optical imaging system by utilizing two or more active optics in a conventional optical system. The system can create relatively large changes in system magnification with very small changes in the focal lengths of individual active elements by leveraging the optical power of the conventional optical elements (e.g., passive lenses and mirrors) surrounding the active optics. The active optics serve primarily as variable focal-length lenses or mirrors, although adding other aberrations enables increased utility. The active optics can either be LC SLMs, used in a transmissive optical zoom system, or DMs, used in a reflective optical zoom system. By appropriately designing the optical system, the variable focal-length lenses or mirrors can provide the flexibility necessary to change the overall system focal length (i.e., effective focal length), and therefore magnification, that is normally accomplished with mechanical motion in conventional zoom lenses. The active optics can provide additional flexibility by allowing magnification to occur anywhere within the FOV of the system, not just on-axis as in a conventional system.

  6. Self-referencing Mach-Zehnder interferometer as a laser system diagnostic: Active and adaptive optical systems

    SciTech Connect

    Feldman, M.; Mockler, D.J.; English, R.E. Jr.; Byrd, J.L.; Salmon, J.T.

    1991-02-01

    We are incorporating a novel self-referencing Mach-Zehnder interferometer into a large scale laser system as a real time, interactive diagnostic tool for wavefront measurement. The instrument is capable of absolute wavefront measurements accurate to better than {lambda}/10 pv over a wavelength range > 300 nm without readjustment of the optical components. This performance is achieved through the design of both refractive optics and catadioptric collimator to achromatize the Mach-Zehnder reference arm. Other features include polarization insensitivity through the use of low angles of incidence on all beamsplitters as well as an equal path length configuration that allows measurement of either broad-band or closely spaced laser-line sources. Instrument accuracy is periodically monitored in place by means of a thermally and mechanically stable wavefront reference source that is calibrated off-line with a phase conjugate interferometer. Video interferograms are analyzed using Fourier transform techniques on a computer that includes dedicated array processor. Computer and video networks maintain distributed interferometers under the control of a single analysis computer with multiple user access. 7 refs., 11 figs.

  7. Spatially Modulated Gain Waveguide Electro-Optic Laser

    DTIC Science & Technology

    2013-08-09

    gain medium profile. We met this goal by implementing a Ti diffused erbium doped active laser waveguide that exploits optical Birefringence, pump beam...sensitivity. An Erbium doped LiNbC>3 waveguide laser theoretically can provide both the narrow linewidth and the higher tuning sensitivity. However, at...Since Erbium doped LiNb03 is homogeneously broadened and the SMG laser contains no spatial hole burning, the single frequency operation is guaranteed

  8. 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.

  9. Laser & Fiber Optics: Instructional Manual. The North Dakota High Technology Mobile Laboratory Project.

    ERIC Educational Resources Information Center

    Eickhoff, Luvern R.

    This instructional manual contains 20 learning activity packets for use in a workshop on lasers and fiber optics. The lessons cover the following topics: what a laser; coherent light; setting up the laser; characteristics of the laser beam; scattering of light; laser beam divergence, intensity, color, ophthalmology, and reflections; directivity of…

  10. Laser & Fiber Optics: Instructional Manual. The North Dakota High Technology Mobile Laboratory Project.

    ERIC Educational Resources Information Center

    Eickhoff, Luvern R.

    This instructional manual contains 20 learning activity packets for use in a workshop on lasers and fiber optics. The lessons cover the following topics: what a laser; coherent light; setting up the laser; characteristics of the laser beam; scattering of light; laser beam divergence, intensity, color, ophthalmology, and reflections; directivity of…

  11. Extreme nonlinear optics and laser damage

    NASA Astrophysics Data System (ADS)

    Maldutis, Evaldas

    2010-11-01

    The study of laser induced damage threshold caused by series of identical laser pulses (LID-T-N) on gamma radiation resistant glasses and their analogs is performed applying know-how ultra stable laser radiation. The presented results and analysis of earlier received results show that nonlinear optical phenomena in extreme conditions of interaction are different from the traditional nonlinear optical processes, because they depend not only on intensity of electromagnetic field of laser radiation, but also on the pulse number in series of identical laser pulses. This range of laser intensities is not wide; it is different for each material and determines the range of Extreme Nonlinear Optics. The dependence of LID-T-N on pulse number N for different kinds of high quality transparent glasses was observed. The study of dynamics of these processes (i.e. the study of dependence on N) at different intensities in series of incident laser pulses provides new information about properties of the materials useful for studying laser damage fundamentals and their application. The expectation that gamma radiation resistant glasses could give useful information for technology of resistant optics for high power lasers has not proved. The received results well correspond with the earlier proposed model of laser damage.

  12. Optically pumped microplasma rare gas laser.

    PubMed

    Rawlins, W T; Galbally-Kinney, K L; Davis, S J; Hoskinson, A R; Hopwood, J A; Heaven, M C

    2015-02-23

    The optically pumped rare-gas metastable laser is a chemically inert analogue to three-state optically pumped alkali laser systems. The concept requires efficient generation of electronically excited metastable atoms in a continuous-wave (CW) electric discharge in flowing gas mixtures near atmospheric pressure. We have observed CW optical gain and laser oscillation at 912.3 nm using a linear micro-discharge array to generate metastable Ar(4s, 1s(5)) atoms at atmospheric pressure. We observed the optical excitation of the 1s(5) → 2p(9) transition at 811.5 nm and the corresponding fluorescence, optical gain and laser oscillation on the 2p(10) ↔ 1s(5) transition at 912.3 nm, following 2p(9)→2p(10) collisional energy transfer. A steady-state kinetics model indicates efficient collisional coupling within the Ar(4s) manifold.

  13. Subwavelength metal-optic semiconductor nanopatch lasers.

    PubMed

    Yu, Kyoungsik; Lakhani, Amit; Wu, Ming C

    2010-04-26

    We report on near infrared semiconductor nanopatch lasers with subwavelength-scale physical dimensions (0.019 cubic wavelengths) and effective mode volumes (0.0017 cubic wavelengths). We observe lasing in the two most fundamental optical modes which resemble oscillating electrical and magnetic dipoles. The ultra-small laser volume is achieved with the presence of nanoscale metal patches which suppress electromagnetic radiation into free-space and convert a leaky cavity into a highly-confined subwavelength optical resonator. Such ultra-small lasers with metallodielectric cavities will enable broad applications in data storage, biological sensing, and on-chip optical communication.

  14. Optically Pumped Carbon Monoxide Cascade Laser

    DTIC Science & Technology

    2005-07-01

    absorption problems it poses. Instead, a 2.3 gtm GaSb diode laser could be used as a 1st overtone optically pumped source. The absorption cross section at...OPTICALLY PUMPED CARBON MONOXIDE CASCADE LASER BY NICHOLAS W. SAWRUK B.S., PHYSICS, US AIR FORCE ACADEMY, 2001 B.S., MATHEMATICS, US AIR FORCE...SUBTITLE 5. FUNDING NUMBERS OPTICALLY PUMPED CARBON MONOXIDE CASCADE LASER 6. AUTHOR(S) 1ST LT SAWRUK NICHOLAS W 7. PERFORMING ORGANIZATION NAME(S) AND

  15. Comparison of high-power diode pumped actively Q-switched double-clad flower shape co-doped-Er3+:Yb3+fiber laser using acousto-optic and mechanical (optical) modulators

    NASA Astrophysics Data System (ADS)

    El-Sherif, Ashraf F.; Harfosh, Amr

    2015-09-01

    A diode-pumped acousto-optic Q-switching Er3+:Yb3+ co-doped high-power fiber laser is reported, laser output average power in excess of 1.65 W was achieved for Q-switching at relatively high repetition rates from 10 to 100 kHz. The shortest pulse duration obtained was 10 ns, giving a highest peak power of 9.8 kW and 98 μJ energy per pulse, this is the highest power yet reported from any type of actively Q-switched flower double-clad Er3+:Yb3+ fiber laser operating in low order mode at 1550 nm. The pulse train with high pulse-to-pulse stability of 95% occurred at a range of repetition rates up to 100 kHz with peak power of 0.4 kW, 40 ns pulse width and 16 μJ energy per pulse at 1550 nm for a launched pump power of 5 W. With the mechanical modulation Q-switching of the Er3+:Yb3+ co-doped fiber laser, it was found that the narrowest pulse width of 35 ns was obtained with peak power of 15.5 kW and energy per pulse 0.5 mJ at pulse repetition frequency of 1 kHz. A moderate pulse-to-pulse stability of 75% occurred over a range of high repetition rates. A comparison between mechanical modulation and acousto-optic Q-switching has been made at a repetition rate of 20 kHz. The energy per pulse, pulse width, and the average power of a mechanical optical Q-switching laser were greater than for the acousto-optic Q-switching, but the pulse width is narrower and so the high peak power of an acousto-optic Q-switching pulse is greater than for the mechanical (optical) Q-switching laser at repetition rates of up to 100 kHz.

  16. Plasma optical modulators for intense lasers

    PubMed Central

    Yu, Lu-Le; Zhao, Yao; Qian, Lie-Jia; Chen, Min; Weng, Su-Ming; Sheng, Zheng-Ming; Jaroszynski, D. A.; Mori, W. B.; Zhang, Jie

    2016-01-01

    Optical modulators can have high modulation speed and broad bandwidth, while being compact. However, these optical modulators usually work for low-intensity light beams. Here we present an ultrafast, plasma-based optical modulator, which can directly modulate high-power lasers with intensity up to 1016 W cm−2 to produce an extremely broad spectrum with a fractional bandwidth over 100%, extending to the mid-infrared regime in the low-frequency side. This concept relies on two co-propagating laser pulses in a sub-millimetre-scale underdense plasma, where a drive laser pulse first excites an electron plasma wave in its wake while a following carrier laser pulse is modulated by the plasma wave. The laser and plasma parameters suitable for the modulator to work are based on numerical simulations. PMID:27283369

  17. REVIEW: Optical frequency standards and femtosecond lasers

    NASA Astrophysics Data System (ADS)

    Baklanov, E. V.; Pokasov, P. V.

    2003-05-01

    A review is presented of the state of the art in a new direction in quantum electronics based on the use of femtosecond lasers for precision frequency measurements and the development of optical frequency and time standards.

  18. Ultraintense lasers: relativistic nonlinear optics and applications

    NASA Astrophysics Data System (ADS)

    Mourou, Gérard A.

    Traditional optics and nonlinear optics are related to laser-matter interaction with eV characteristic energy. Recent progresses in ultrahigh intensity makes it possible to drive electrons with relativistic energy opening up the field of relativistic nonlinear optics. In the last decade, lasers have undergone orders-of-magnitude jumps in peak power, with the invention of the technique of chirped pulse amplification (CPA) and the refinements of femtosecond techniques. Modern CPA lasers can produce intensities greater than 10 21 W/cm 2, one million times greater than previously possible. These ultraintense lasers give researchers a tool to produce unprecedented pressures (terabars), magnetic fields (gigagauss), temperatures (10 10 K), and accelerations (10 25 g) with applications in fusion energy, nuclear physics (fast ignition), high-energy physics, astrophysics, and cosmology. They promote the optics field from the eV to the GeV.

  19. Laser treatments of active acne.

    PubMed

    Wiznia, Lauren E; Stevenson, Mary L; Nagler, Arielle R

    2017-08-04

    The utility of laser therapy is increasingly being recognized in the treatment of active acne vulgaris. We aimed to perform a narrative review of the medical literature on the use of laser therapy for the treatment of active acne vulgaris. We performed a PubMed literature search on September 1, 2016 using the search terms "active acne," "acne," "laser therapy," and "laser surgery." Case reports, case series, cohort, and controlled trials were included. Studies of lasers in the treatment of acne, including erbium glass, Nd:YAG, pulse dye laser (PDL), potassium titanyl phosphate (KTP) laser, and laser-based photodynamic therapy, have been published. While treatment of active acne with lasers has been successful, many studies are limited by small patient number and lack of control populations and comparison to standard therapies for active acne. Laser therapies are increasingly becoming part of or an adjunct to the medical treatment of active acne and are a useful treatment modality.

  20. Semiconductor laser gyro with optical frequency dithering

    SciTech Connect

    Prokof'eva, L P; Sakharov, V K; Shcherbakov, V V

    2014-04-28

    The semiconductor laser gyro is described, in which the optical frequency dithering implemented by intracavity phase modulation suppresses the frequency lock-in and provides the interference of multimode radiation. The sensitivity of the device amounted to 10–20 deg h{sup -1}. (laser gyroscopes)

  1. Optical and Kinetic Processes in Excimer Lasers

    DTIC Science & Technology

    1993-03-01

    investigations of the spectroscopy and chemical kinetics of XeF and XeCl lasers using theoretical techniques , synchrotron radiation excitation, and laser... technique for characterizing potential SBS media. Our work is described in Appendices N and 0. 3 OTHER TOPICS IN LASERS AND NONLINEAR OPTICS The SRS and... technique described above for several fluorine and chlorine donors are shown in Table 1. The quanitities in parentheses indicate where the yields have

  2. Laser fiber optics ordnance initiation system

    NASA Technical Reports Server (NTRS)

    Yang, L. C.

    1976-01-01

    Recent progress on system development in the laser initiation of explosive devices is summarized. The topics included are: development of compact free-running mode and Q-switched lasers, development of low-loss fiber optic bundles and connectors, study of nuclear radiation effects on the system, characterization of laser initiation sensitivities of insensitive high explosives, and the design methods used to achieve attractive system weight and cost savings. Direction for future work is discussed.

  3. Laser fiber optics ordnance initiation system

    NASA Technical Reports Server (NTRS)

    Yang, L. C.

    1976-01-01

    Recent progress on system development in the laser initiation of explosive devices is summarized. The topics included are: development of compact free-running mode and Q-switched lasers, development of low-loss fiber optic bundles and connectors, study of nuclear radiation effects on the system, characterization of laser initiation sensitivities of insensitive high explosives, and the design methods used to achieve attractive system weight and cost savings. Direction for future work is discussed.

  4. Coupled optical resonance laser locking.

    PubMed

    Burd, S C; du Toit, P J W; Uys, H

    2014-10-20

    We have demonstrated simultaneous laser frequency stabilization of a UV and IR laser, to coupled transitions of ions in the same spectroscopic sample, by detecting only the absorption of the UV laser. Separate signals for locking the different lasers are obtained by modulating each laser at a different frequency and using lock-in detection of a single photodiode signal. Experimentally, we simultaneously lock a 369 nm and a 935 nm laser to the (2)S(1/2) → (2)(P(1/2) and (2)D(3/2) → (3)D([3/2]1/2) transitions, respectively, of Yb(+) ions generated in a hollow cathode discharge lamp. Stabilized lasers at these frequencies are required for cooling and trapping Yb(+) ions, used in quantum information and in high precision metrology experiments. This technique should be readily applicable to other ion and neutral atom systems requiring multiple stabilized lasers.

  5. Electro-optics and lasers in Israel

    NASA Astrophysics Data System (ADS)

    Van Zwaren, Joesph

    1992-05-01

    With over 3,000 scientists, engineers, and technicians spread out in some 86 companies, and in 10 universities and research institutes, all within less than a 2 hour drive from one another, Israel has no doubt one of the largest concentrations of researchers and skilled manpower in electro-optics and lasers in the world. This report presents an up-to-date picture of the field in Israel, covering the industry, academia and education. The recent wave of Russian immigration is bringing thousands of scientists and tens of thousands of engineers and is expected to make an impact on the field of electro-optics and lasers. A million immigrants from Russia are expected to come between 1990 and 1995. There were 3,700 scientists and 2,800 engineers among the first 200,000 Soviet immigrants. As most of this qualified manpower can not be expected to be absorbed by the existing industry, the Israeli government is actively encouraging local and foreign investors and local and multinational companies to help develop new and expanded high-tech enterprises in Israel. The Ministry of Industry and Trade has embarked upon a broad ranged program for industrial growth and immigrant absorption with the goal of doubling technology-based exports in the next four years. The Ministry of Science and Technology has started a program supporting R&D projects at the different universities for immigrant scientists with the goal of capitalizing on the talents of the newcomers to strengthen academia.

  6. Optically pumped molecular bromine laser. Master's thesis

    SciTech Connect

    Morrison, J.W.

    1990-12-01

    An optically pumped molecular bromine laser was studied to investigate the quenching kinetics state of Br2. This included characterization of the pressure dependence of the laser output power. The approach was to excite molecular bromine in a sealed cell with a Nd:YAG pumped dye laser. Unresolved side fluorescence and amplified stimulated emission (ASE) spectra were recorded. ASE offered the advantage of a simpler optical system with no externally induced wavelength dependencies. Stimulated emission as a signal monitor offered greater resolution than side fluorescence spectra and facilitated spectroscopic assignment. (JS)

  7. Optically Pumped Carbon Monoxide Cascade Laser

    DTIC Science & Technology

    2005-06-30

    bother with the small absorption cross-sections of 2nd overtone pumping and the absorption problems it poses. Instead, a 2.3 µm GaSb diode laser ...could be used as a 1 st overtone optically pumped source. The absorption cross section at 2.3 µm is over 100 times larger. The 2.3 µm diode laser is...AFRL-DE-PS- AFRL-DE-PS- TR-2005-1093 TR-2005-1093 OPTICALLY PUMPED CARBON MONOXIDE CASCADE LASER NICHOLAS W. SAWRUK 30 June 2005 Final Report

  8. Mobile fiber-optic laser Doppler anemometer.

    PubMed

    Stieglmeier, M; Tropea, C

    1992-07-20

    A laser Doppler anemometer (LDA) has been developed that combines the compactness and low power consumption of laser diodes and avalanche photodiodes with the flexibility and possibility of miniaturization by using fiber-optic probes. The system has been named DFLDA for laser diode fiber LDA and is especially suited for mobile applications, for example, in trains, airplanes, or automobiles. Optimization considerations of fiber-optic probes are put forward and several probe examples are described in detail. Measurement results from three typical applications are given to illustrate the use of the DFLDA. Finally, a number of future configurations of the DFLDA concept are discussed.

  9. Optical wavelength modulation in free electron lasers

    SciTech Connect

    Mabe, R.M.; Wong, R.K.; Colson, W.B.

    1995-12-31

    An attribute of the free electron laser (FEL) is the continuous tunability of the optical wavelength by modulation of the electron beam energy. The variation of the wavelength and power of the optical beam is studied as a function of FEL operating parameters. These results will be applied to the Stanford SCA FEL and Boeing FEL.

  10. Laser-optic instruments improve machinery alignment

    SciTech Connect

    Bloch, H.P.

    1987-10-12

    Laser-optic alignment systems are fast becoming cost-effective devices that improve the accuracy and speed of machinery shaft alignment. Because of the difficulty, if not impossibility, of aligning operating machinery, cold alignment specifications must be determined to compensate for thermal growth so that the shaft alignment remains within tolerances when the machine reaches normal operating temperature. Some methods for accomplishing this are reviewed here. Three years' field experience with laser-optic alignment systems shows that many of these limitations can be eliminated, resulting in a more accurate alignment in less time. Some actual field alignments are given as examples of the improvement achieved by the use of laser equipment, and a procedure is given that shows how the laser-optic system may be used to determine running alignment changes caused by thermal growth.

  11. Optical communication with laser diode arrays

    NASA Technical Reports Server (NTRS)

    Davidson, F.

    1984-01-01

    The performance of a direct-detection optical communication system in which the laser transmitter sends short optical pulses of selected nonoverlapping center frequencies is analysed. This modulation format, in which a single light pulse is sent in one of M time slots at one of N optical center frequencies, is referred to as color coded optical pulse position modulation (CCPPM). The optimum energy-efficiency of this system, as measured by the channel capacity in nats per photon, exceeds that of ordinary optical pulse position modulation which uses a pulsed laser of fixed optical frequency. Reliable communication at optimal energy efficiency is easily achieved through the use of modest block length Reed-Solomon codes with the code words represented as CCPPM symbols.

  12. Optical Feedback Stabilization of Laser Diodes for Passive Resonance Ring Laser Gyro Applications.

    DTIC Science & Technology

    1985-12-01

    rugged optical rotation sensors are not far off. The main purpose of this research was to a construct narrow spectral linewidth semiconductor laser . In... Linewidth and Sensitivity Pssive Resonant Ring Laser Gyroscopes............. Frequency Noise and Laser Linewidth ............. 8.......... * Laser Diode... Linewidth Reduction by Optical F ee dbk........................... ck . . .. . . . 12 Semiconductor Laser Mode Behavior with Optical Feedback

  13. Plasma spectroscopy using optical vortex laser

    NASA Astrophysics Data System (ADS)

    Yoshimura, Shinji; Aramaki, Mitsutoshi; Terasaka, Kenichiro; Toda, Yasunori; Czarnetzki, Uwe; Shikano, Yutaka

    2014-10-01

    Laser spectroscopy is a useful tool for nonintrusive plasma diagnostics; it can provide many important quantities in a plasma such as temperature, density, and flow velocity of ions and neutrals from the spectrum obtained by scanning the frequency of narrow bandwidth laser. Obtainable information is, however, limited in principle to the direction parallel to the laser path. The aim of this study is to introduce a Laguerre-Gaussian beam, which is called as optical vortex, in place of a widely used Hermite-Gaussian beam. One of the remarkable properties of the Laguerre-Gaussian beam is that it carries an angular momentum in contrast to the Hermite-Gaussian beam. It follows that particles in the laser beam feel the Doppler effect even in the transverse direction of the laser path. Therefore it is expected that the limitation imposed by the laser path can be overcome by using an optical vortex laser. The concept of optical vortex spectroscopy, the development of the laser system, and some preliminary results of a proof-of-principle experiment will be presented. This work is performed with the support and under the auspices of NINS young scientists collaboration program for cross-disciplinary study, NIFS collaboration research program (NIFS13KOAP026), and JSPS KAKENHI Grant Number 25287152.

  14. Optical tweezers using a diode laser

    NASA Astrophysics Data System (ADS)

    Afzal, Robert S.; Treacy, E. Brian

    1992-04-01

    Simple modifications were made to a commercial microscope to enable injection of light from a diode laser, and demonstrate optical tweezers action. The basic properties of microscope optics are presented together with discussion of principles to be followed in arranging the external optics for achieving useful tweezers. Procedures using a single-mode diode laser along with experimental results are presented in enough detail to permit readers to make their own system for trapping and manipulating single cells. It is surprisingly easy to demonstrate tweezers action once some basic concepts are understood.

  15. Modeling the Laser Interferometer Space Antenna Optics

    NASA Technical Reports Server (NTRS)

    Waluschka, Eugene; Pedersen, Trace R.; McNamara, Paul

    2005-01-01

    Creating an optical model of the Laser Interferometer Space antenna which can be used to predict optical sensitivities and set tolerances sufficiently well such that picometer level displacements can be reliably seen poses certain challenges. In part, because the distances between key optical elements, the proof masses, are constantly changing, at speeds of meters/second, the separation between them is about 5 million kilometers and a contributing factor to optical jitter is the self-gravity of the spacecraft. A discussion of the current state and future approach(s) to the creation of such an optical model will be presented.

  16. Third order mode optically pumped semiconductor laser

    NASA Astrophysics Data System (ADS)

    De Rossi, A.; Semaltianos, N.; Chirlias, E.; Vinter, B.; Ortiz, V.; Berger, V.

    2002-06-01

    Lasing action on a third order waveguide mode is demonstrated at room temperature under optical pumping, in a specifically designed quantum well laser structure. The AlGaAs heterostructure involves barriers which ensure that the third order waveguide mode has a higher overlap with the single quantum well emitter than the fundamental mode. Third order mode operation of a laser structure opens the way to modal phase matched parametric down conversion inside the semiconductor laser itself. It is a first step towards the realization of semiconductor twin photon laser sources, needed for quantum information experiments.

  17. Optical contact approach to laser rod support.

    NASA Technical Reports Server (NTRS)

    Gurski, T. R.

    1972-01-01

    The successful application of an optical contact is described between a ruby laser rod that has no mechanical support and a sapphire rod. The contact is found to be durable in the environmental conditions associated with a high-power pulsed ruby laser. The described contact technique makes it possible to construct a laser oscillator using an ellipsoidal pump mirror that does not employ dielectric coatings in the cavity. Another advantage consists in that the ruby laser is not shaded from the pump light by mounting jigs at its ends.

  18. 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.

  19. Beam shaping for laser initiated optical primers

    NASA Astrophysics Data System (ADS)

    Lizotte, Todd E.

    2008-08-01

    Remington was one of the first firearm manufacturing companies to file a patent for laser initiated firearms, in 1969. Nearly 40 years later, the development of laser initiated firearms has not become a mainstream technology in the civilian market. Requiring a battery is definitely a short coming, so it is easy to see how such a concept would be problematic. Having a firearm operate reliably and the delivery of laser energy in an efficient manner to ignite the shock-sensitive explosive primer mixtures is a tall task indeed. There has been considerable research on optical element based methods of transferring or compressing laser energy to ignite primer charges, including windows, laser chip primers and various lens shaped windows to focus the laser energy. The focusing of laser light needs to achieve igniting temperatures upwards of >400°C. Many of the patent filings covering this type of technology discuss simple approaches where a single point of light might be sufficient to perform this task. Alternatively a multi-point method might provide better performance, especially for mission critical applications, such as precision military firearms. This paper covers initial design and performance test of the laser beam shaping optics to create simultaneous multiple point ignition locations and a circumferential intense ring for igniting primer charge compounds. A simple initial test of the ring beam shaping technique was evaluated on a standard large caliber primer to determine its effectiveness on igniting the primer material. Several tests were conducted to gauge the feasibility of laser beam shaping, including optic fabrication and mounting on a cartridge, optic durability and functional ignition performance. Initial data will be presented, including testing of optically elements and empirical primer ignition / burn analysis.

  20. Circularly polarized optical heterodyne interferometer for optical activity measurement of a quartz crystal.

    PubMed

    Chou, Chien; Kuo, Wen-Chuan; Han, Chien-Yuan

    2003-09-01

    Phase retardation between two orthogonal circularly polarized light waves that propagate in an optical active medium is proportional to its optical activity. The measurement of optical activity of a quartz depolarizer in terms of the phase difference of two orthogonal circularly polarized waves is proposed. A circularly polarized optical heterodyne interferometer with a Zeeman laser to measure the optical activity of a quartz crystal is demonstrated experimentally. The accuracy of the measurement is discussed. In addition, the effect of elliptical polarization and nonorthogonality of linearly polarized light waves of a Zeeman laser on the optical activity measurement is analyzed.

  1. Laser with optically driven Q-switch

    NASA Technical Reports Server (NTRS)

    Hemmati, Hamid (Inventor)

    1995-01-01

    An optically driven interactive Q-switch, i.e., a Q-switch that responds to a short pulse of light, for example, from external light-emitting diodes (LED's) or diode lasers, is provided for producing an output laser pulse from electronic energy stored in a laser medium. Q-switching is thus achieved on demand by electrically pulsing the light source to produce a pulse of light directed onto a Q-switch medium in the laser cavity. Electronic control of the light pulse from the external source will thus provide not only efficient Q-switching frequency but also independent control of output laser pulse width with a fast rise time for each output laser pulse.

  2. Laser with optically driven Q-switch

    NASA Technical Reports Server (NTRS)

    Hemmati, Hamid (Inventor)

    1993-01-01

    An optically driven interactive Q-switch, i.e., a Q-switch that responds to a short pulse of light, for example, from external light-emitting diodes (LEDs) or diode lasers, is provided for producing an output laser pulse from electronic energy stored in a laser medium. Q-switching is thus achieved on demand by electrically pulsing the light source to produce a pulse of light directed onto a Q-switch medium in the laser cavity. Electronic control of the light pulse from the external source will thus provide not only efficient Q-switching frequency but also independent control of output laser pulse width with a fast rise time for each output laser pulse.

  3. Space Optical Communications Using Laser Beam Amplification

    NASA Technical Reports Server (NTRS)

    Agrawal, Govind

    2015-01-01

    The Space Optical Communications Using Laser Beam Amplification (SOCLBA) project will provide a capability to amplify a laser beam that is received in a modulating retro-reflector (MRR) located in a satellite in low Earth orbit. It will also improve the pointing procedure between Earth and spacecraft terminals. The technology uses laser arrays to strengthen the reflected laser beam from the spacecraft. The results of first year's work (2014) show amplification factors of 60 times the power of the signal beam. MMRs are mirrors that reflect light beams back to the source. In space optical communications, a high-powered laser interrogator beam is directed from the ground to a satellite. Within the satellite, the beam is redirected back to ground using the MMR. In the MMR, the beam passes through modulators, which encode a data signal onto the returning beam. MMRs can be used in small spacecraft for optical communications. The SOCLBA project is significant to NASA and small spacecraft due to its application to CubeSats for optical data transmission to ground stations, as well as possible application to spacecraft for optical data transmission.

  4. Optical complexity in external cavity semiconductor laser

    NASA Astrophysics Data System (ADS)

    Rondoni, Lamberto; Ariffin, M. R. K.; Varatharajoo, Renuganth; Mukherjee, Sayan; Palit, Sanjay K.; Banerjee, Santo

    2017-03-01

    In this article, the window based complexity and output modulation of a time delayed chaotic semiconductor laser (SL) model has been investigated. The window based optical complexity (OC), is measured by introducing the recurrence sample entropy (SampEn). The analysis has been done without and in the presence of external noise. The significant changes in the dynamics can be observed under induced noise with weak strength. It has also been found that there is a strong positive correlation between the output power and the complexity of the system with various sets of parameters. The laser intensity, as well as the OC can be increased with the incremental noise strength and the associated system parameters. Thus, optical complexity quantifies the system dynamics and its instabilities, since is strongly correlated with the laser outputs. This analysis can be applied to measure the laser instabilities and modulation of output power.

  5. The theory of optical black hole lasers

    NASA Astrophysics Data System (ADS)

    Gaona-Reyes, José L.; Bermudez, David

    2017-05-01

    The event horizon of black holes and white holes can be achieved in the context of analogue gravity. It was proven for a sonic case that if these two horizons are close to each other their dynamics resemble a laser, a black hole laser, where the analogue of Hawking radiation is trapped and amplified. Optical analogues are also very successful and a similar system can be achieved there. In this work we develop the theory of optical black hole lasers and prove that the amplification is also possible. Then, we study the optical system by determining the forward propagation of modes, obtaining an approximation for the phase difference which governs the amplification, and performing numerical simulations of the pulse propagation of our system.

  6. Fiber optic coherent laser radar 3d vision system

    SciTech Connect

    Sebastian, R.L.; Clark, R.B.; Simonson, D.L.

    1994-12-31

    Recent advances in fiber optic component technology and digital processing components have enabled the development of a new 3D vision system based upon a fiber optic FMCW coherent laser radar. The approach includes a compact scanner with no moving parts capable of randomly addressing all pixels. The system maintains the immunity to lighting and surface shading conditions which is characteristic of coherent laser radar. The random pixel addressability allows concentration of scanning and processing on the active areas of a scene, as is done by the human eye-brain system.

  7. Design and Characterization of Optically Pumped Vertical Cavity Surface Emitting Lasers

    DTIC Science & Technology

    1992-12-01

    01 Design and Characterization of Optically Pumped Vertical Cavity Surface Emitting Lasers THESIS Presented to the Faculty of the School of Engineering...VCSELs ............................ 3-11 3.4 Injection Lasers : Electrical Pumping .................... 3-12 3.4.1 Active Region Design... lasers on the wafer. x Design and Characterization of Optically Pumped Vertical Cavity Surface Emitting Lasers L. Introduction This thesis investigates

  8. Optical scanning system for laser velocimeter

    NASA Technical Reports Server (NTRS)

    Rhodes, D. B.

    1977-01-01

    An optical system was developed to provide fast incremental scanning of a backscattered laser velocimeter focus point over a 36-cm distance. The system is used to measure flow velocities at 16 positions along its optical axis and to scan these 16 positions up to 30 times a second. Dwell time at each location is approximately 2 milliseconds. Sample volumes typically are 0.2 mm in diameter by 1.4 cm in length. The optical scanning system consists of a wheel containing plane parallel quartz windows of various thicknesses. The laser velocimeter beams are imaged to a primary focus within the dead airspace of an optical cell. The beams emerging from the cell pass through the windows of the scanning wheel. The refraction of the beams passing through the windows causes an apparent shift of the focus within the optical cell and hence in the test zone. Light scattered from the secondary focus within the test zone is concurrently collected and reimaged through the same optical path which originally projected the primary focus. The reimaged backscattered light containing the velocity information is then collected and focused onto a photomultiplier detector system to complete the scanned laser velocimeter optical system.

  9. Adaptive Optics Imaging in Laser Pointer Maculopathy.

    PubMed

    Sheyman, Alan T; Nesper, Peter L; Fawzi, Amani A; Jampol, Lee M

    2016-08-01

    The authors report multimodal imaging including adaptive optics scanning laser ophthalmoscopy (AOSLO) (Apaeros retinal image system AOSLO prototype; Boston Micromachines Corporation, Boston, MA) in a case of previously diagnosed unilateral acute idiopathic maculopathy (UAIM) that demonstrated features of laser pointer maculopathy. The authors also show the adaptive optics images of a laser pointer maculopathy case previously reported. A 15-year-old girl was referred for the evaluation of a maculopathy suspected to be UAIM. The authors reviewed the patient's history and obtained fluorescein angiography, autofluorescence, optical coherence tomography, infrared reflectance, and AOSLO. The time course of disease and clinical examination did not fit with UAIM, but the linear pattern of lesions was suspicious for self-inflicted laser pointer injury. This was confirmed on subsequent questioning of the patient. The presence of linear lesions in the macula that are best highlighted with multimodal imaging techniques should alert the physician to the possibility of laser pointer injury. AOSLO further characterizes photoreceptor damage in this condition. [Ophthalmic Surg Lasers Imaging Retina. 2016;47:782-785.]. Copyright 2016, SLACK Incorporated.

  10. Nonlinear optical protection against frequency agile lasers

    SciTech Connect

    McDowell, V.P.

    1988-08-04

    An eye-protection or equipment-filter device for protection from laser energy is disclosed. The device may be in the form of a telescope, binoculars, goggles, constructed as part of equipment such as image intensifiers or range designators. Optical elements focus the waist of the beam within a nonlinear frequency-doubling crystal or nonlinear optical element or fiber. The nonlinear elements produce a harmonic outside the visible spectrum in the case of crystals, or absorb the laser energy in the case of nonlinear fibers. Embodiments include protectors for the human eye as well as filters for sensitive machinery such as TV cameras, FLIR systems or other imaging equipment.

  11. Optical communication with semiconductor laser diode

    NASA Technical Reports Server (NTRS)

    Davidson, Frederic; Sun, X.

    1989-01-01

    This interim report describes the progress in the construction of a 220 Mbps Q=4 PPM optical communication system that uses a semiconductor laser as the optical transmitter and an avalanche photodiode (APD) as the photodetector. The transmitter electronics have been completed and contain both GaAs and ECL III IC's. The circuit was able to operate at a source binary data rate from 75 Mbps to 290 Mbps with pulse rise and fall times of 400 ps. The pulse shapes of the laser diode and the response from the APD/preamplifier module were also measured.

  12. Laser and Optical Fiber Metrology in Romania

    SciTech Connect

    Sporea, Dan; Sporea, Adelina

    2008-04-15

    The Romanian government established in the last five years a National Program for the improvement of country's infrastructure of metrology. The set goal was to develop and accredit testing and calibration laboratories, as well as certification bodies, according to the ISO 17025:2005 norm. Our Institute benefited from this policy, and developed a laboratory for laser and optical fibers metrology in order to provide testing and calibration services for the certification of laser-based industrial, medical and communication products. The paper will present the laboratory accredited facilities and some of the results obtained in the evaluation of irradiation effects of optical and optoelectronic parts, tests run under the EU's Fusion Program.

  13. Laser and Optical Fiber Metrology in Romania

    NASA Astrophysics Data System (ADS)

    Sporea, Dan; Sporea, Adelina

    2008-04-01

    The Romanian government established in the last five years a National Program for the improvement of country's infrastructure of metrology. The set goal was to develop and accredit testing and calibration laboratories, as well as certification bodies, according to the ISO 17025:2005 norm. Our Institute benefited from this policy, and developed a laboratory for laser and optical fibers metrology in order to provide testing and calibration services for the certification of laser-based industrial, medical and communication products. The paper will present the laboratory accredited facilities and some of the results obtained in the evaluation of irradiation effects of optical and optoelectronic parts, tests run under the EU's Fusion Program.

  14. ADAPTIVE OPTICS: Laser refractography of optically inhomogeneous media

    NASA Astrophysics Data System (ADS)

    Raskovskaya, I. L.; Rinkevichyus, B. S.; Tolkachev, A. V.

    2007-12-01

    The basic principles of laser refractography, a new method for diagnostics of optically inhomogeneous media and flows based on refraction of spatially structured laser radiation, are described. By using 2D- and 3D-refraction patterns, the medium under investigation can be visualised and the inhomogeneity profile can be diagnosed quantitatively. The method is modified for studying edge effects and thin boundary layers in liquids and gases. Due to nearly inertialess measurements, laser refractography can be used for diagnostics of fast and transient processes. The simultaneous diagnostics of processes in various regions is provided by an extended radiation source.

  15. Laser Electro-Optic Technology. Florida Vocational Program Guide.

    ERIC Educational Resources Information Center

    University of South Florida, Tampa. Dept. of Adult and Vocational Education.

    This program guide identifies primary considerations in the organization, operation, and evaluation of a laser electro-optic technology program. An occupational description and program content are presented. A curriculum framework specifies the exact course title, course number, levels of instruction, major course content, laboratory activities,…

  16. Laser Electro-Optic Technology. Florida Vocational Program Guide.

    ERIC Educational Resources Information Center

    University of South Florida, Tampa. Dept. of Adult and Vocational Education.

    This program guide identifies primary considerations in the organization, operation, and evaluation of a laser electro-optic technology program. An occupational description and program content are presented. A curriculum framework specifies the exact course title, course number, levels of instruction, major course content, laboratory activities,…

  17. Optical Path Difference Evaluation of Laser-Soldered Optical Components

    NASA Astrophysics Data System (ADS)

    Burkhardt, T.; Hornaff, M.; Burkhardt, D.; Beckert, E.

    2015-12-01

    We present Solderjet Bumping, a laser-based soldering process, as an all inorganic joining technique for optical materials and mechanical support structures. The adhesive-free bonding process enables the low-stress assembly of fragile and sensitive components for advanced optical systems. Our process addresses high demanding applications, e.g. under high energetic radiation (short wavelengths of 280 nm and below and/or high intensities), for vacuum operation, and for harsh environmental conditions. Laser-based soldering allows the low stress assembly of aligned sub-cells as key components for high quality optical systems. The evaluation of the optical path difference in fused silica and the radiation resistant LAK9G15 glass components after soldering and environmental testing shows the potential of the technique.

  18. Optical Detection Theory for Laser Applications

    NASA Astrophysics Data System (ADS)

    Osche, Gregory R.

    2002-07-01

    A comprehensive treatment of the fundamentals of optical detection theory Laser system applications are becoming more numerous, particularly in the fields of communications and remote sensing. Filling a significant gap in the literature, Optical Detection Theory for Laser Applications addresses the theoretical aspects of optical detection and associated phenomenologies, describing the fundamental optical, statistical, and mathematical principles of the modern laser system. The book is especially valuable for its extensive treatment of direct detection statistics, which has no analog in radar detection theory and which has never before been compiled in a cohesive manner in a single book. Coverage includes: * A review of mathematical statistics and statistical decision theory * Performance of truncated and untruncated coherent and direct detection systems using Huygens-Fresnel and Gaussian beam theories * Rough surface scatter and atmospheric propagation effects * Single-pulse detection statistics for direct and coherent detection systems * Multi-pulse detection statistics for direct and coherent detection systems Supported by additional comments providing further insights into the physics or mathematics discussed and an extensive list of classic references, Optical Detection Theory for Laser Applications comprises a much-needed reference for the professional scientist or engineer, as well as a solid textbook for advanced students.

  19. Aero-optics overview. [laser applications

    NASA Technical Reports Server (NTRS)

    Gilbert, K. G.

    1980-01-01

    Various aero-optical phenomena are discussed with reference to their effect on airborne high energy lasers. Major emphasis is placed on: compressibility effects induced in the surrounding flow field; viscous effects which manifests themselves as aircraft boundary layers or shear layers; inviscid flow fields surrounding the aircraft due to airflow around protuberance such as laser turret assemblies; and shocks, established whenever local flow exceeds Mach one. The significant physical parameters affecting the interaction of a laser beam with a turbulent boundary layer are also described.

  20. Optical eye simulator for laser dazzle events.

    PubMed

    Coelho, João M P; Freitas, José; Williamson, Craig A

    2016-03-20

    An optical simulator of the human eye and its application to laser dazzle events are presented. The simulator combines optical design software (ZEMAX) with a scientific programming language (MATLAB) and allows the user to implement and analyze a dazzle scenario using practical, real-world parameters. Contrary to conventional analytical glare analysis, this work uses ray tracing and the scattering model and parameters for each optical element of the eye. The theoretical background of each such element is presented in relation to the model. The overall simulator's calibration, validation, and performance analysis are achieved by comparison with a simpler model based uponCIE disability glare data. Results demonstrate that this kind of advanced optical eye simulation can be used to represent laser dazzle and has the potential to extend the range of applicability of analytical models.

  1. Simplified Optics and Controls for Laser Communications

    NASA Technical Reports Server (NTRS)

    Chen, Chien-Chung; Hemmati, Hamid

    2006-01-01

    A document discusses an architecture of a spaceborne laser communication system that provides for a simplified control subsystem that stabilizes the line of sight in a desired direction. Heretofore, a typical design for a spaceborne laser communication system has called for a high-bandwidth control loop, a steering mirror and associated optics, and a fast steering-mirror actuator to stabilize the line of sight in the presence of vibrations. In the present architecture, the need for this fast steering-mirror subsystem is eliminated by mounting the laser-communication optics on a disturbance-free platform (DFP) that suppresses coupling of vibrations to the optics by 60 dB. Taking advantage of microgravitation, in the DFP, the optical assembly is free-flying relative to the rest of the spacecraft, and a low-spring-constant pointing control subsystem exerts small forces to regulate the position and orientation of the optics via voice coils. All steering is effected via the DFP, which can be controlled in all six degrees of freedom relative to the spacecraft. A second control loop, closed around a position sensor and the spacecraft attitude-control system, moves the spacecraft as needed to prevent mechanical contact with the optical assembly.

  2. High Stability Optical Mount for Space Laser Applications

    NASA Astrophysics Data System (ADS)

    Mosciarello, P.; Di Carmine, E.

    2014-06-01

    In the frame of Atmospheric Lidar (ATLID) project, one of the active instruments foreseen to be boarded on the EarthCARE satellite, a high stability optical mount has been designed, developed and tested in order to fulfil the tight program requirements.A description of the design solution developed, manufactured and qualified for the most critical optical mount inside the PLH, located on the Laser Master Oscillator Plate (the laser resonance cavity), is presented. In order to minimize optical mount mass and envelope, the developed solution foresees a glued interface (I/F) between the mechanical support and the mirror.A collection of stability results obtained on the optical mount breadboards is also presented, including a description of environmental tests performed and the way to assess the mirror stability after each environmental test, as well as the acceptance criteria derived in order to establish the flight worthiness of the manufactured and assembled hardware.

  3. Electro-Optical Laser Technology. Curriculum Utilization. Final Report.

    ERIC Educational Resources Information Center

    Nawn, John H.

    This report describes a program to prepare students for employment as laser technicians and laser operators and to ensure that they have the necessary skills required by the industry. The objectives are to prepare a curriculum and syllabus for an associate degree program in Electro-Optical Laser Technology. The 2-year Electro-Optical Laser program…

  4. Optical turbulence in fiber lasers.

    PubMed

    Wabnitz, Stefan

    2014-03-15

    We analyze the nonlinear stage of modulation instability in passively mode-locked fiber lasers leading to chaotic or noise-like emission. We present the phase-transition diagram among different regimes of chaotic emission in terms of the key cavity parameters: amplitude or phase turbulence, and spatio-temporal intermittency.

  5. Monolithic resonant optical reflector laser diodes

    NASA Astrophysics Data System (ADS)

    Hirata, T.; Suehiro, M.; Maeda, M.; Hihara, M.; Hosomatsu, H.

    1991-10-01

    The first monolithic resonant optical reflector laser diode that has a waveguide directional coupler and two DBR reflectors integrated by compositional disordering of quantum-well heterostructures is described. A linewidth of 440 kHz was obtained, and this value is expected to be greatly decreased by reducing the propagation loss in the integrated waveguide.

  6. Airborne Visible Laser Optical Communications (AVLOC) experiment

    NASA Technical Reports Server (NTRS)

    1974-01-01

    A series of optical communication experiments between a high altitude aircraft at 18.3 km (60,000 ft) and a ground station were conducted by NASA from summer 1972 through winter 1973. The basic system was an optical tracker and transmitter located in each terminal. The aircraft transceiver consisted of a 5-mW HeNe laser transmitter with a 30-megabit modulator. The ground station beacon was an argon laser operating at 488 nm. A separate pulsed laser radar was used for initial acquisition. The objective of the experiment was to obtain engineering data on the precision tracking and communication system performance at both terminals. Atmospheric effects on the system performance was also an experiment objective. The system description, engineering analysis, testing, and flight results are discussed.

  7. Optical design of laser transmission system

    NASA Astrophysics Data System (ADS)

    Zhang, Yulan; Feng, Jinliang; Li, Yongliang; Yang, Jiandong

    1998-08-01

    This paper discusses a design of optical transfer system used in carbon-dioxide laser therapeutic machine. The design of this system is according to the requirement of the therapeutic machine. The therapeutic machine requires the movement of laser transfer system is similar to the movement of human beings arms, which possesses 7 rotating hinges. We use optical hinges, which is composed of 45 degree mirrors. Because the carbon-dioxide laser mode is not good, light beam diameter at focus and divergence angle dissemination are big, we use a collecting lens at the transfer system output part in order to make the light beam diameter at focus in 0.2 to approximately 0.3 mm. For whole system the focus off-axis error is less than 0.5 mm, the transfer power consumption is smaller than 10%. The system can move in three dimension space freely and satisfies the therapeutic machine requirement.

  8. Nanosecond pulsed laser texturing of optical diffusers

    NASA Astrophysics Data System (ADS)

    Alqurashi, Tawfiq; Sabouri, Aydin; Yetisen, Ali K.; Butt, Haider

    2017-02-01

    High-quality optical glass diffusers have applications in aerospace, displays, imaging systems, medical devices, and optical sensors. The development of rapid and accurate fabrication techniques is highly desirable for their production. Here, a micropatterning method for the fast fabrication of optical diffusers by means of nanosecond pulsed laser ablation is demonstrated (λ=1064 nm, power=7.02, 9.36 and 11.7 W and scanning speed=200 and 800 mm s-1). The experiments were carried out by point-to-point texturing of a glass surface in spiral shape. The laser machining parameters, the number of pulses and their power had significant effect on surface features. The optical characteristics of the diffusers were characterized at different scattering angles. The features of the microscale structures influenced average roughness from 0.8 μm to 1.97 μm. The glass diffusers scattered light at angles up to 20° and their transmission efficiency were measured up to ˜97% across the visible spectrum. The produced optical devices diffuse light less but do so with less scattering and energy losses as compared to opal diffusing glass. The presented fabrication method can be applied to any other transparent material to create optical diffusers. It is anticipated that the optical diffusers presented in this work will have applications in the production of LED spotlights and imaging devices.

  9. Laser-driven polyplanar optic display

    SciTech Connect

    Veligdan, J.T.; Biscardi, C.; Brewster, C.; DeSanto, L.; Beiser, L.

    1998-01-01

    The Polyplanar Optical Display (POD) is a unique display screen which can be used with any projection source. This display screen is 2 inches thick and has a matte-black face which allows for high contrast images. The prototype being developed is a form, fit and functional replacement display for the B-52 aircraft which uses a monochrome ten-inch display. The new display uses a 200 milliwatt green solid-state laser (532 nm) as its optical source. In order to produce real-time video, the laser light is being modulated by a Digital Light Processing (DLP) chip manufactured by Texas Instruments, Inc. A variable astigmatic focusing system is used to produce a stigmatic image on the viewing face of the POD. In addition to the optical design, the authors discuss the DLP chip, the optomechanical design and viewing angle characteristics.

  10. 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.

  11. Laser-optic Measurements of Velocity of Particles in the Powder Stream at Coaxial Laser Cladding

    NASA Astrophysics Data System (ADS)

    Sergachev, D. V.; Mikhal'chenko, A. A.; Kovalev, O. B.; Kuz'min, V. I.; Grachev, G. N.; Pinaev, P. A.

    The problems of particle velocity and temperature measurement can be solved with commonly-known methods of registration based on spectrometry and a complex of laser and optical means. The diagnostic technique combines two independent methods of particle velocity measurement, namely the passive way which is based on the intrinsic radiation of the heated particles in a gas flow, and the active one which utilizes the effect of the laser beam scattering. It is demonstrated that the laser radiation can affect significantly the particles velocity at the laser cladding. Presented bar charts of statistical distributions of the particles velocities illustrate two modes of the coaxial nozzle performance, with and without СО2-laser radiation. Different types of powders (Al2O3, Mo, Ni, Al) were used in tests, the particle size distributions were typical for the laser cladding; air, nitrogen, argon were used as working gases, continuous radiation of the СО2 laser reached 3 kW. It is shown that in the laser-radiation field, the powder particles undergo extra acceleration due to the laser evaporation and reactive force occurrence resulting from the recoil pressure vapors from the beamed part of particles' surfaces. The observed effect of particles acceleration depends on the particles concentration in the powder flow. Due to the laser acceleration, the velocities of individual particles may reach the values of about 80 - 100 m/s. The trichromatic pyrometry method was utilized to measure the particles temperature in the powder flow.

  12. Adaptive optics and laser guide stars at Lick observatory

    SciTech Connect

    Brase, J.M.

    1994-11-15

    For the past several years LLNL has been developing adaptive optics systems for correction of both atmospheric turbulence effects and thermal distortions in optics for high-power lasers. Our early work focused on adaptive optics for beam control in laser isotope separation and ground-based free electron lasers. We are currently developing innovative adaptive optics and laser systems for sodium laser guide star applications at the University of California`s Lick and Keck Observeratories. This talk will describe our adaptive optics technology and some of its applications in high-resolution imaging and beam control.

  13. Development of Optical Pickup for Digital Versatile Disc Using Two-Wavelength-Integrated Laser Diode

    NASA Astrophysics Data System (ADS)

    Uchiyama, Mineharu; Ebihara, Takeshi; Omi, Kunio; Kitano, Hisashi; Hoshino, Isao; Mori, Kazushige

    2000-03-01

    A digital versatile disc (DVD)-and compact disc (CD)-compatible optical pickup using a two-wavelength-integrated laser diode (TWIN-LD) has been developed. The TWIN-LD has two emission points in one chip, one for the red laser beam to read out signals from DVDs and the other for the IR laser beam to read out signals from CDs that are arranged along the active layer. With the application of a TWIN-LD to the optical pickup, the necessity for four optical components, namely, a laser diode, photodetector, holographic optical element and dichroic prism, is avoided in comparison with conventional optical pickups. This paper discusses some key points for designing an optical system using a TWIN-LD, and the results of the experiments appling the optical system to an optical pickup 7.3 mm in height.

  14. Catadioptric Optics for laser Doppler velocimeter applications

    NASA Technical Reports Server (NTRS)

    Dunagan, Stephen E.

    1989-01-01

    In the design of a laser velocimeter system, attention must be given to the performance of the optical elements in their two principal tasks: focusing laser radiation into the probe volume, and collecting the scattered light. For large aperture applications, custom lens design and fabrication costs, long optical path requirements, and chromatic aberration (for two color operation) can be problematic. The adaptation of low cost Schmidt-Cassegrain astronomical telescopes to perform these laser beam manipulation and scattered light collection tasks is examined. A generic telescope design is analyzed using ray tracing and Gaussian beam propagation theory, and a simple modification procedure for converting from infinite to near unity conjugate ratio operation with image quality near the diffraction limit was identified. Modification requirements and performance are predicted for a range of geometries. Finally, a 200-mm-aperture telescope was modified for f/10 operation; performance data for this modified optic for both laser beam focusing and scattered light collection tasks agree well with predictions.

  15. Optical bending sensor using distributed feedback solid state dye lasers on optical fiber.

    PubMed

    Kubota, Hiroyuki; Oomi, Soichiro; Yoshioka, Hiroaki; Watanabe, Hirofumi; Oki, Yuji

    2012-07-02

    Novel type of optical fiber sensor was proposed and demonstrated. The print-like fabrication technique fabricates multiple distributed feedback solid state dye lasers on a polymeric optical fiber (POF) with tapered coupling. This multi-active-sidecore structure was easily fabricated and provides multiple functions. Mounting the lasers on the same point of a multimode POF demonstrated a bending radius sensitivity of 20 m without any supports. Two axis directional sensing without cross talk was also confirmed. A more complicated mounting formation can demonstrate a twisted POF. The temperature property of the sensor was also studied, and elimination of the temperature influence was experimentally attained.

  16. A non-critically phase matched KTA optical parametric oscillator intracavity pumped by an actively Q-switched Nd:GYSGG laser with dual signal wavelengths

    NASA Astrophysics Data System (ADS)

    Zhong, Kai; Guo, Shibei; Wang, Maorong; Mei, Jialin; Xu, Degang; Yao, Jianquan

    2015-06-01

    A non-critically phase matched eye-safe KTA optical parametric oscillator intracavity pumped by a dual-wavelength acousto-optically Q-switched Nd:GYSGG laser is demonstrated. Simultaneous dual signal wavelength at 1525.1 nm/1531.2 nm can be realized using only one laser crystal and one nonlinear crystal. When the absorbed diode pump power at 808 nm is 7.48 W, the maximum output power, single pulse energy and peak power are 296 mW, 2.96 μJ and 6.4 kW, respectively. As the signal wavelengths exactly locates at the absorption band of C2H2, such an Nd:GYSGG/KTA eye-safe laser has good application prospects in differential absorption lidar (DIAL) for C2H2 detection and difference frequency generation for terahertz waves at 0.77 THz.

  17. Laser action by optically depumping lower states

    DOEpatents

    Krupke, W.F.

    1975-11-26

    A method and apparatus are described for obtaining laser action between an upper energy level and a lower energy level of a gaseous medium. The upper energy level is populated to some degree (short of achieving a conventional inverted population) by any suitable pumping means, and an inverted population is established by transiently and selectively depumping the lower energy level. The depumping may be done by exposing the medium to an intense source of radiation which selectively causes the transformation of the lower energy level species to some other energy level. Thus, a thermally pumped/optically depumped gas laser system is produced.

  18. Laser action by optically depumping lower states

    DOEpatents

    Krupke, William F.

    1977-01-01

    A method and apparatus for obtaining laser action between an upper energy level and a lower energy level of a gaseous medium, which comprises populating the upper energy level to some degree (short of achieving a conventional inverted population) by any suitable pumping means, and thereafter establishing an inverted population by transiently and selectively depumping the lower energy level such as by exposing the medium to an intense source of radiation which selectively causes the transformation of the lower energy level species to some other energy level. Thus, a thermally pumped/optically depumped gas laser system is produced.

  19. Terahertz graphene lasers: Injection versus optical pumping

    SciTech Connect

    Ryzhii, Victor; Otsuji, Taiichi; Ryzhii, Maxim; Mitin, Vladimir

    2013-12-04

    We analyze the formation of nonequilibrium states in optically pumped graphene layers and in forward-biased graphene structures with lateral p-i-n junctions and consider the conditions of population inversion and lasing. The model used accounts for intraband and interband relaxation processes as well as deviation of the optical phonon system from equilibrium. As shown, optical pumping suffers from a significant heating of both the electron-hole plasma and the optical phonon system, which can suppress the formation of population inversion. In the graphene structures with p-i-n junction, the injected electrons and holes have relatively low energies, so that the effect of cooling can be rather pronounced, providing a significant advantage of the injection pumping in realization of graphene terahertz lasers.

  20. Integrated optic chip for laser threat identification

    NASA Astrophysics Data System (ADS)

    McAulay, Alastair D.

    2010-04-01

    In this conference last year, we proposed free-space gratings, Fizeau interferometers and wavefront estimation for detecting the different lasers deployed in the battlefield for range finding, target designation, communications, dazzle, location of targets, munitions guidance, and destruction. Since last year, advanced laser weapons of the electron cyclotron type, are in development, such as the free-electron laser, that are tunable and can, unlike conventional bound-electron state lasers, be used at any wavelength from microwaves to soft X-rays. We list the characteristics of the nine dominant laser weapons because we assume that the free-electron lasers will initially use one of the current threat wavelengths because of availability of components and instrumentation. In this paper we replace the free-space grating with a higher performing array waveguide grating integrated optic chip, similar to that used in telecommunications, because integrated circuits are more robust and less expensive. It consists of a star coupler that fans out amongst waveguides of different length followed by a star coupler that focuses different wavelengths to different outputs in order to separate them. Design equations are derived to cover a range of frequencies at specific frequency spacing relevant to this application.

  1. Femtosecond laser polishing of optical materials

    NASA Astrophysics Data System (ADS)

    Taylor, Lauren L.; Qiao, Jun; Qiao, Jie

    2015-10-01

    Technologies including magnetorheological finishing and CNC polishing are commonly used to finish optical elements, but these methods are often expensive, generate waste through the use of fluids or abrasives, and may not be suited for specific freeform substrates due to the size and shape of finishing tools. Pulsed laser polishing has been demonstrated as a technique capable of achieving nanoscale roughness while offering waste-free fabrication, material-specific processing through direct tuning of laser radiation, and access to freeform shapes using refined beam delivery and focusing techniques. Nanosecond and microsecond pulse duration radiation has been used to perform successful melting-based polishing of a variety of different materials, but this approach leads to extensive heat accumulation resulting in subsurface damage. We have experimentally investigated the ability of femtosecond laser radiation to ablate silicon carbide and silicon. By substituting ultrafast laser radiation, polishing can be performed by direct evaporation of unwanted surface asperities with minimal heating and melting, potentially offering damage-free finishing of materials. Under unoptimized laser processing conditions, thermal effects can occur leading to material oxidation. To investigate these thermal effects, simulation of the heat accumulation mechanism in ultrafast laser ablation was performed. Simulations have been extended to investigate the optimum scanning speed and pulse energy required for processing various substrates. Modeling methodologies and simulation results will be presented.

  2. Ranging performance of active laser detection

    NASA Astrophysics Data System (ADS)

    Sun, Huayan; Xiong, Fei; Gu, Suolin

    2006-06-01

    Ranging performance is described for photoelectric equipment reconnaissance using an active laser detection system that is based on the 'cat's eyes' effect of optical windows. Active laser detection systems have an advantage over passive systems because they can measure target velocity and spatial coordinates. However, there are several challenging problems here because of the great distances involved, the low returned power of the uncooperative target, and the optical aberrations induced by the atmosphere. In the design of this system, the principle of detection is based on the 'cat's eyes' effect according to which the optical windows of photoelectric equipments have a strong reflect character towards incident laser beam. With 'cat's eyes' effect, the detection of uncooperative target can be translated into one of a cooperative target, so the ratio of returned laser can be increased. In this paper, the ranging performance presented here takes into account all the various elements of the system, from the laser emission, target, atmospheric propagation to the detector. The characteristics of back-reflected laser and an estimate of the laser Cross Section (LCS) from 'cat's eyes target' are investigated in theory and simulation. The Signal-to-Noise Ratio (SNR) is calculated by combining the probability of detection of the system for given electronic characteristics of the system and for a given probability of false alarms. On the basis of analysis of SNR, minimum detectable signal power, operating distance of the system and factors affecting the ranging performance is analyzed. Results indicate that system has characters of long range, and high sensitivity. It can be used to detect the aerial targets such as reconnaissance drone, navigate missile, reconnaissance satellite etc.

  3. Lens based adaptive optics scanning laser ophthalmoscope.

    PubMed

    Felberer, Franz; Kroisamer, Julia-Sophie; Hitzenberger, Christoph K; Pircher, Michael

    2012-07-30

    We present an alternative approach for an adaptive optics scanning laser ophthalmoscope (AO-SLO). In contrast to other commonly used AO-SLO instruments, the imaging optics consist of lenses. Images of the fovea region of 5 healthy volunteers are recorded. The system is capable to resolve human foveal cones in 3 out of 5 healthy volunteers. Additionally, we investigated the capability of the system to support larger scanning angles (up to 5°) on the retina. Finally, in order to demonstrate the performance of the instrument images of rod photoreceptors are presented.

  4. Studies of Beam Expansion and Distributed Bragg Reflector Lasers for Fiber Optics and Optical Signal Processing.

    DTIC Science & Technology

    1981-03-03

    block number) Separate studies were performed on beam expansion and on Distributed Bragg Reflector ( DBR ) lasers preliminary to monolithic integration on...Reflector ( DBR ) laser is a light source compatible with monolithic integrated optics. In the DBR laser one or both cleaved endfaces of a typical double...cleave as a laser cavity mirror. The DBR laser can be used as an integrated optics light source for integrated optical circuits. In this report we

  5. Guide star lasers for adaptive optics

    NASA Astrophysics Data System (ADS)

    Roberts, William Thomas, Jr.

    Exploitation of the imaging capabilities of the new generation of ground-based astronomical telescopes relies heavily on Adaptive Optics (AO). Current AO system designs call for sodium guide star lasers capable of producing at least eight Watts of power tuned to the peak of the sodium D2 line, with a high duty cycle to avoid saturation, and with 0.5-1.0 GHz spectral broadening. This work comprises development and testing of six candidate laser systems and materials which may afford a path to achieving these goals. An end-pumped CW dye laser producing 4.0 Watts of tuned output power was developed and used to obtain the first accurate measurement of sodium layer scattering efficiency. Methods of optimizing the laser output through improving pump overlap efficiency and reducing the number of intracavity scattering surfaces are covered. The 1181 nm fluorescence peak of Mn5+ ion in Ba5 (PO4)3Cl could be tuned and doubled to reach 589 nm. While efforts to grow this crystal were under way, the Mn5+ ion in natural apatite (Ca5(PO4)3F) was studied as a potential laser material. Fluorescence saturation measurements and transmission saturation are presented, as well as efforts to obtain CW lasing in natural apatite. A Q-switched laser color-center laser in LiF : F-2 was developed and successfully tuned and doubled to the sodium D 2 line. Broad-band lasing of 80 mW and tuned narrow-band lasing of 35 mW at 1178 nm were obtained with 275 mW of input pump power at 1064 nm. The measured thermal properties of this material indicate its potential for scaling to much higher power. A Q-switched intracavity Raman laser was developed in which CaWO 4 was used to shift a Nd:YAG laser, the frequency-doubled output of which was centered at 589.3 nm. To obtain light at 589.0 nm, a compositionally tuned pump laser of Nd : Y3Ga1.1Al3.9O 12 was produced which generated the desired shift, but was inhomogeneous broadened, limiting the tunable power of the material. Finally, temperature tuning of

  6. Optical polymers for laser medical applications

    NASA Astrophysics Data System (ADS)

    Sultanova, Nina G.; Kasarova, Stefka N.; Nikolov, Ivan D.

    2016-01-01

    In medicine, optical polymers are used not only in ophthalmology but in many laser surgical, diagnostic and therapeutic systems. The application in lens design is determined by their refractive and dispersive properties in the considered spectral region. We have used different measuring techniques to obtain precise refractometric data in the visible and near-infrared spectral regions. Dispersive, thermal and other important optical characteristics of polymers have been studied. Design of a plastic achromatic objective, used in a surgical stereo-microscope at 1064 nm laser wavelength, is accomplished. Geometrical and wavefront aberrations are calculated. Another example of application of polymers is the designed all-mirror apochromatic micro-lens, intended for superluminescent diode fiber coupling in medical systems.

  7. Optically injected quantum-dot lasers.

    PubMed

    Erneux, T; Viktorov, E A; Kelleher, B; Goulding, D; Hegarty, S P; Huyet, G

    2010-04-01

    The response of an optically injected quantum-dot semiconductor laser (SL) is studied both experimentally and theoretically. In particular, the nature of the locking boundaries is investigated, revealing features more commonly associated with Class A lasers rather than conventional Class B SLs. Experimentally, two features stand out; the first is an absence of instabilities resulting from relaxation oscillations, and the second is the observation of a region of bistability between two locked solutions. Using rate equations appropriate for quantum-dot lasers, we analytically determine the stability diagram in terms of the injection rate and frequency detuning. Of particular interest are the Hopf and saddle-node locking boundaries that explain how the experimentally observed phenomena appear.

  8. LASER BEAMS: Optical diabols in singular laser beams

    NASA Astrophysics Data System (ADS)

    Vasil'ev, V. I.; Denisenko, V. G.; Egorov, R. I.; Slyusar, V. V.; Soskin, M. S.

    2008-03-01

    Polarisation singularities and optical diabols in laser beams are studied experimentally by the developed method of digital Stokes-polarimetry. Three possible morphological forms of singularities with circular polarisation (C points) are found and their statistics in the speckle pattern of photoinduced scattering is determined. Singular fields with controllable parameters are realised and used for studying topological transformations, creation and annihilation of singularities and optical diabols. Both possible types of distributions of the major and minor semiaxes of polarisation ellipses in the beam cross section around C points (optical diabols) are measured. It is shown that, in accordance with the theory, the annihilation of pairs of elliptical diabols is preceded by their transformation to hyperbolic diabols.

  9. Optical injection in semiconductor ring lasers

    NASA Astrophysics Data System (ADS)

    Coomans, W.; Beri, S.; Sande, G. Van Der; Gelens, L.; Danckaert, J.

    2010-03-01

    We theoretically investigate optical injection in semiconductor ring lasers and disclose several dynamical regimes. Through numerical simulations and bifurcation continuation, two separate parameter regions in which two different injection-locked solutions coexist are revealed, in addition to a region in which a frequency-locked limit cycle coexists with an injection-locked solution. Finally, an antiphase chaotic regime without the involvement of any carrier dynamics is revealed. Parallels are drawn with the onset of chaos in the periodically forced Duffing oscillator.

  10. Use laser-optics for machinery alignment

    SciTech Connect

    Bloch, H.P.

    1987-10-01

    Many sources attribute most bearing overload and destructive vibration in industrial machinery to shaft misalignment. There is considerable disagreement as to the alignment quality required. There is also little agreement on suitable calculation methods and achievable accuracy for anticipated thermal growth of machinery (necessary if running alignment is to remain acceptable). This article examines existing alignment quality guidelines for relevance and consistency, and reviews the application of laser-optic alignment systems based on three years of field experience.

  11. Active optical zoom system.

    PubMed

    Wang, Di; Wang, Qiong-Hua; Shen, Chuan; Zhou, Xin; Liu, Chun-Mei

    2014-11-01

    In this work, we propose an active optical zoom system. The zoom module of the system is formed by a liquid lens and a spatial light modulator (SLM). By controlling the focal lengths of the liquid lens and the encoded digital lens on the SLM panel, we can change the magnification of an image without mechanical moving parts and keep the output plane stationary. The magnification can change from 1/3 to 3/2 as the focal length of the encoded lens on the SLM changes from infinity to 24 cm. The proposed active zoom system is simple and flexible, and has widespread application in optical communications, imaging systems, and displays.

  12. Optic cavitation with CW lasers: A review

    NASA Astrophysics Data System (ADS)

    Padilla-Martinez, J. P.; Berrospe-Rodriguez, C.; Aguilar, G.; Ramirez-San-Juan, J. C.; Ramos-Garcia, R.

    2014-12-01

    The most common method to generate optic cavitation involves the focusing of short-pulsed lasers in a transparent liquid media. In this work, we review a novel method of optic cavitation that uses low power CW lasers incident in highly absorbing liquids. This novel method of cavitation is called thermocavitation. Light absorbed heats up the liquid beyond its boiling temperature (spinodal limit) in a time span of microseconds to milliseconds (depending on the optical intensity). Once the liquid is heated up to its spinodal limit (˜300 °C for pure water), the superheated water becomes unstable to random density fluctuations and an explosive phase transition to vapor takes place producing a fast-expanding vapor bubble. Eventually, the bubble collapses emitting a strong shock-wave. The bubble is always attached to the surface taking a semi-spherical shape, in contrast to that produced by pulsed lasers in transparent liquids, where the bubble is produced at the focal point. Using high speed video (105 frames/s), we study the bubble's dynamic behavior. Finally, we show that heat diffusion determines the water superheated volume and, therefore, the amplitude of the shock wave. A full experimental characterization of thermocavitation is described.

  13. LDEF active optical system components experiment

    NASA Technical Reports Server (NTRS)

    Blue, M. D.

    1992-01-01

    A preliminary report on the Active Optical System Components Experiment is presented. This experiment contained 136 components in a six inch deep tray including lasers, infrared detectors and arrays, ultraviolet light detectors, light-emitting diodes, a light modulator, flash lamps, optical filters, glasses, and samples of surface finishes. Thermal, mechanical, and structural considerations leading to the design of the tray hardware are discussed. In general, changes in the retested component characteristics appear as much related to the passage of time as to the effects of the space environment, but organic materials, multilayer optical interference filters, and extreme-infrared reflectivity of black paints show unexpected changes.

  14. Actively coupled optical waveguides

    NASA Astrophysics Data System (ADS)

    Alexeeva, N. V.; Barashenkov, I. V.; Rayanov, K.; Flach, S.

    2014-01-01

    We consider light propagation through a pair of nonlinear optical waveguides with absorption, placed in a medium with power gain. The active medium boosts the in-phase component of the overlapping evanescent fields of the guides, while the nonlinearity of the guides couples it to the damped out-of-phase component creating a feedback loop. As a result, the structure exhibits stable stationary and oscillatory regimes in a wide range of gain-loss ratios. We show that the pair of actively coupled (AC) waveguides can act as a stationary or integrate-and-fire comparator sensitive to tiny differences in their input powers.

  15. Resonant activation in bistable semiconductor lasers

    SciTech Connect

    Lepri, Stefano; Giacomelli, Giovanni

    2007-08-15

    We theoretically investigate the possibility of observing resonant activation in the hopping dynamics of two-mode semiconductor lasers. We present a series of simulations of a rate-equation model under random and periodic modulation of the bias current. In both cases, for an optimal choice of the modulation time scale, the hopping times between the stable lasing modes attain a minimum. The simulation data are understood by means of an effective one-dimensional Langevin equation with multiplicative fluctuations. Our conclusions apply to both edge-emitting and vertical cavity lasers, thus opening the way to several experimental tests in such optical systems.

  16. Ring gas lasers with magneto-optical control for laser gyroscopy (invited paper)

    SciTech Connect

    Azarova, V V; Golyaev, Yu D; Dmitriev, Valentin G

    2000-02-28

    The main physical principles of the operation of ring gas lasers in the laser-gyroscope regime are examined. The influence of nonreciprocal effects on the operational parameters of ring gas lasers and the methods of controlling, with the aid of the nonreciprocal magneto-optical Zeeman effect, the parameters of these lasers used in gyroscopes are discussed. (laser gyroscopes)

  17. Nanosecond laser damage of optical multimode fibers

    NASA Astrophysics Data System (ADS)

    Mann, Guido; Krüger, Jörg

    2016-07-01

    For pulse laser materials processing often optical step index and gradient index multimode fibers with core diameters ranging from 100 to 600 μm are used. The design of a high power fiber transmission system must take into account limitations resulting from both surface and volume damage effects. Especially, breakdown at the fiber end faces and selffocusing in the fiber volume critically influence the fiber performance. At least operation charts are desirable to select the appropriate fiber type for given laser parameters. In industry-relevant studies the influence of fiber core diameter and end face preparation on laser-induced (surface) damage thresholds (LIDT) was investigated for frequently used all-silica fiber types (manufacturer LEONI). Experiments on preform material (initial fiber material) and compact specimens (models of the cladding and coating material) accompanied the tests performed in accordance with the relevant LIDT standards ISO 21254-1 and ISO 21254-2 for 1-on-1 and S-on-1 irradiation conditions, respectively. The relation beam diameter vs. LIDT was investigated for fused silica fibers. Additionally, laser-induced (bulk) damage thresholds of fused silica preform material F300 (manufacturer Heraeus) in dependence on external mechanical stress simulating fiber bending were measured. All experiments were performed with 10-ns laser pulses at 1064 and 532 nm wavelength with a Gaussian beam profile.

  18. Optical autofocus for high resolution laser photoplotting

    NASA Astrophysics Data System (ADS)

    Alonso, Jose; Crespo, Daniel; Jimenez, Isidoro; Bernabeu, Eusebio

    2005-07-01

    An all optical autofocus has been designed and tested for tight line width control in a high NA laser photoplotter system. The laser system is based in a GaN semiconductor laser with power 30 mW and wavelength 405 nm. The advantage of using this laser, despite the relatively long wavenlength, is compactness and easy for high frequency modulation. The autofocus system is based in a secondary 635 nm GaAlAs laser without need for wavelength, neither power stabilization. The two beams are delivered coaxially through the focusing lens by means of a dichroic beamsplitter. Focusing lens need no correction for chromatic aberration, as this is compensed by appropriate autofocus beam divergence. After reflection in the sample, the autofocus beam is separated from the returning writing beam and then guided to a collimation sensor, in which defocus of about 1/20 of the Rayleigh range of the writing beam can be detected and compensated by an analogue PID electronic control. Stable linewidth within 5% is achieved with different numerical aperture focusing lenses.

  19. Stabilization of class-B broad-area laser emission by external optical injection

    NASA Astrophysics Data System (ADS)

    Pakhomov, A. V.; Arkhipov, R. M.; Molevich, N. E.

    2017-04-01

    We theoretically examine the effect of external optical injection on the spatio-temporal dynamics of class-B broad-area lasers. We demonstrate that optical injection can efficiently stabilize the intrinsic transverse instabilities in such lasers associated with both the boundaries of the pumping area and with the bulk nonlinearities of the active medium. Stabilizing action of optical injection is shown to be closely related to the suppression of inherent relaxation oscillations behavior.

  20. Graphene actively Q-switched lasers

    NASA Astrophysics Data System (ADS)

    Li, Diao; Xue, Hui; Qi, Mei; Wang, Yadong; Aksimsek, Sinan; Chekurov, Nikolai; Kim, Wonjae; Li, Changfeng; Riikonen, Juha; Ye, Fangwei; Dai, Qing; Ren, Zhaoyu; Bai, Jintao; Hasan, Tawfique; Lipsanen, Harri; Sun, Zhipei

    2017-06-01

    Graphene electro-optic modulators (GEOMs) are emerging as a viable alternative to conventional material-based modulators mainly due to their broadband and ultrafast performance. These GEOMs with combined advantages of small footprint and low energy consumption can potentially enable various high-performance applications that are not possible using conventional approaches. Here, we report the first actively Q-switched lasers with a GEOM. In contrast to the previously reported lasers that are passively modulated by two-dimensional layered material-based saturable absorbers, our actively modulated laser concept represents significant advantages, such as electrically tunable output parameters (e.g. output repetition rate, pulse duration and pulse energy) and electro-optical synchronization. Using a single GEOM, we generate broadband Q-switched pulses at  ∼1.55 and 2 μm with output energies of up to 123 nJ. This indicates the broadband pulse generation capability of the graphene-based active devices, superior to widely used bulk material-based active modulation approaches. Our results demonstrate a simple and viable design towards broadband, high-repetition-rate, electrically modulated ultrafast lasers for various applications, such as telecommunications and spectroscopy.

  1. Even Illumination from Fiber-Optic-Coupled Laser Diodes

    NASA Technical Reports Server (NTRS)

    Howard, Richard T.

    2006-01-01

    A method of equipping fiber-optic-coupled laser diodes to evenly illuminate specified fields of view has been proposed. The essence of the method is to shape the tips of the optical fibers into suitably designed diffractive optical elements. One of the main benefits afforded by the method would be more nearly complete utilization of the available light. Diffractive optics is a relatively new field of optics in which laser beams are shaped by use of diffraction instead of refraction.

  2. Laser controlled atom source for optical clocks.

    PubMed

    Kock, Ole; He, Wei; Świerad, Dariusz; Smith, Lyndsie; Hughes, Joshua; Bongs, Kai; Singh, Yeshpal

    2016-11-18

    Precision timekeeping has been a driving force in innovation, from defining agricultural seasons to atomic clocks enabling satellite navigation, broadband communication and high-speed trading. We are on the verge of a revolution in atomic timekeeping, where optical clocks promise an over thousand-fold improvement in stability and accuracy. However, complex setups and sensitivity to thermal radiation pose limitations to progress. Here we report on an atom source for a strontium optical lattice clock which circumvents these limitations. We demonstrate fast (sub 100 ms), cold and controlled emission of strontium atomic vapours from bulk strontium oxide irradiated by a simple low power diode laser. Our results demonstrate that millions of strontium atoms from the vapour can be captured in a magneto-optical trap (MOT). Our method enables over an order of magnitude reduction in scale of the apparatus. Future applications range from satellite clocks testing general relativity to portable clocks for inertial navigation systems and relativistic geodesy.

  3. Laser controlled atom source for optical clocks

    NASA Astrophysics Data System (ADS)

    Kock, Ole; He, Wei; Świerad, Dariusz; Smith, Lyndsie; Hughes, Joshua; Bongs, Kai; Singh, Yeshpal

    2016-11-01

    Precision timekeeping has been a driving force in innovation, from defining agricultural seasons to atomic clocks enabling satellite navigation, broadband communication and high-speed trading. We are on the verge of a revolution in atomic timekeeping, where optical clocks promise an over thousand-fold improvement in stability and accuracy. However, complex setups and sensitivity to thermal radiation pose limitations to progress. Here we report on an atom source for a strontium optical lattice clock which circumvents these limitations. We demonstrate fast (sub 100 ms), cold and controlled emission of strontium atomic vapours from bulk strontium oxide irradiated by a simple low power diode laser. Our results demonstrate that millions of strontium atoms from the vapour can be captured in a magneto-optical trap (MOT). Our method enables over an order of magnitude reduction in scale of the apparatus. Future applications range from satellite clocks testing general relativity to portable clocks for inertial navigation systems and relativistic geodesy.

  4. Packaging considerations of fiber-optic laser sources

    NASA Astrophysics Data System (ADS)

    Heikkinen, Veli; Tukkiniemi, Kari; Vaehaekangas, Jouko; Hannula, Tapio

    1991-12-01

    The continuous progress in material and component technology has generated new laser-based applications that require special packaging techniques. Hybrid integration offers a flexible method to accomplish custom design needs. This paper discusses several aspects in fiber optic packaging including optical, thermal, and mechanical issues. Special emphasis is on optical coupling between a laser diode and a single-mode fiber.

  5. Optics detection and laser countermeasures on a combat vehicle

    NASA Astrophysics Data System (ADS)

    Sjöqvist, Lars; Allard, Lars; Pettersson, Magnus; Börjesson, Per; Lindskog, Nils; Bodin, Johan; Widén, Anders; Persson, Hâkan; Fredriksson, Jan; Edström, Sten

    2016-10-01

    Magnifying optical assemblies used for weapon guidance or rifle scopes may possess a threat for a combat vehicle and its personnel. Detection and localisation of optical threats is consequently of interest in military applications. Typically a laser system is used in optics detection, or optical augmentation, to interrogate a scene of interest to localise retroreflected laser radiation. One interesting approach for implementing optics detection on a combat vehicle is to use a continuous scanning scheme. In addition, optics detection can be combined with laser countermeasures, or a laser dazzling function, to efficiently counter an optical threat. An optics detection laser sensor demonstrator has been implemented on a combat vehicle. The sensor consists of a stabilised gimbal and was integrated together with a LEMUR remote electro-optical sight. A narrow laser slit is continuously scanned around the horizon to detect and locate optical threats. Detected threats are presented for the operator within the LEMUR presentation system, and by cueing a countermeasure laser installed in the LEMUR sensor housing threats can be defeated. Results obtained during a field demonstration of the optics detection sensor and the countermeasure laser will be presented. In addition, results obtained using a dual-channel optics detection system designed for false alarm reduction are also discussed.

  6. Broad-Area Laser Diode With Fiber-Optic Injection

    NASA Technical Reports Server (NTRS)

    Hazel, Geoffrey; Mead, Patricia; Davis, Christopher; Cornwell, Donald

    1992-01-01

    Fiber-optic injection-locked broad-area laser diode features single-mode output via fiber-optic injection and serves as compact, rugged, high-power near-infrared source. Useful in free-space and fiber-optic communication links, as communication-receiver preamplifier, and pump source for solid-state lasers.

  7. Optical efficiency and gain dynamics of modelocked semiconductor disk lasers.

    PubMed

    Alfieri, C G E; Waldburger, D; Link, S M; Gini, E; Golling, M; Eisenstein, G; Keller, U

    2017-03-20

    Compact optically pumped passively modelocked semiconductor disk lasers (SDLs) based on active quantum wells (QWs) such as vertical external-cavity surface-emitting lasers (VECSELs) or modelocked integrated external-cavity surface-emitting lasers (MIXSELs) are wavelength-versatile sources that offer a unique combination of gigahertz pulse repetition rates and short pulse durations. In this paper, we present record-short pulses of 184 fs from a gigahertz MIXSEL emitting at a center wavelength of 1048 nm. This result comes at the expense of low optical-to-optical pump efficiency (<1%) and average output power limited to 115 mW. We experimentally observe that shorter pulses significantly reduce the macroscopic gain saturation fluence and develop a QW model based on rate equations to reproduce the gain saturation behavior and quantitatively explain the VECSEL and MIXSEL modelocking performances. We identify spectral hole burning as the main cause of the reduced gain at shorter pulse durations, which in combination with the short lifetime of the excited carriers strongly reduces the optical pump efficiency. Our better understanding will help to address these limitations in future ultrafast SDL designs.

  8. Thermo-optic nonlinearity of the laser dye LDS 867 under low power CW laser excitation

    NASA Astrophysics Data System (ADS)

    Mary, K. A. Ann; Mary, E. J. Sonia; Vidyadharan, Viji; Philip, Reji; Unnikrishnan, N. V.

    2015-02-01

    Thermally induced optical nonlinearity of the laser dye LDS 867 is studied in ethanol solution using the self phase modulation and closed aperture z-scan techniques, employing a continuous wave low power He-Ne laser beam for excitation. The nonlinear optical (NLO) coefficients are obtained by analyzing the z-scan curve on the basis of the thermal lens model. The dye exhibits a negative thermal nonlinearity which can be inferred from the occurrence of a pre-focal peak followed by a post-focal valley in the z-scan. The large nonlinear refractive index (n2) measured at the excitation wavelength of 633nm reveals that the material is NLO active even at low excitation powers of less than 1 mW. Results indicate that LDS 867 is a promising material for optical power limiting applications.

  9. The optically pumped semiconductor membrane external-cavity surface-emitting laser (MECSEL): a concept based on a diamond-sandwiched active region

    NASA Astrophysics Data System (ADS)

    Kahle, Hermann; Mateo, Cherry May N.; Brauch, Uwe; Bek, Roman; Jetter, Michael; Graf, Thomas; Michler, Peter

    2017-02-01

    Semiconductor disk lasers with all their advantages1 became an important stand-alone class of solid-state lasers during the last years. However, these systems suffer from heat incorporation into the active region caused by the excess energy of the pump photons. To overcome this limitation we realized the semiconductor membrane external-cavity surface-emitting laser as a diamond heat spreader sandwiched active region design. A detailed process description towards the MECSEL2 approach is given as well as fundamental performance values. Furthermore, parasitic lateral lasing effects are discovered and investigated. Nevertheless, the MECSEL approach indicates enormous potential to revolutionize the semiconductor based disk lasers regarding available output powers at room temperature and material combinations.

  10. Grating THz laser with optical pumping

    NASA Astrophysics Data System (ADS)

    Khoury, Jed; Haji-saeed, Bahareh; Woods, Charles; Kierstead, John

    2010-04-01

    In this paper, we present a design for a widely tunable solid-state optically and electrically pumped THz laser based on the Smith-Purcell free-electron laser. In the free-electron laser, an energetic electron beam pumps a metallic grating to generate surface plasmons. Our solid-state optically pumped design consists of a thin layer of dielectic, such as SiNx, sandwiched between a corrugated structure and a thin metal or semiconductor layer. The lower layer is for current streaming, and replaces the electron beam in the original design. The upper layer consists of one micro-grating for coupling the electromagnetic field in, another for coupling out, and a nano-grating for coupling with the current in the lower layer for electromagnetic field generation. The surface plasmon waves generated from the upper layer by an external electromagnetic field, and the lower layer by the applied current, are coupled. Emission enhancement occurs when the plasmonic waves in both layers are resonantly coupled.

  11. Laser guide star adaptive optics: Present and future

    SciTech Connect

    Olivier, S.S.; Max, C.E.

    1993-03-01

    Feasibility demonstrations using one to two meter telescopes have confirmed the utility of laser beacons as wavefront references for adaptive optics systems. Laser beacon architectures suitable for the new generation of eight and ten meter telescopes are presently under study. This paper reviews the concept of laser guide star adaptive optics and the progress that has been made by groups around the world implementing such systems. A description of the laser guide star program at LLNL and some experimental results is also presented.

  12. Advanced Optical Fibers for High power Fiber lasers

    DTIC Science & Technology

    2015-08-24

    0704-0188 3. DATES COVERED (From - To) - UU UU UU UU 24-08-2015 Approved for public release; distribution is unlimited. Advanced Optical Fibers for...0946 ABSTRACT Advanced Optical Fibers for High power Fiber lasers Report Title A review of recent fiber developement for high power fiber lasers...Chapter 7 Advanced Optical Fibers for High Power Fiber Lasers Liang Dong Additional information is available at the end of the chapter http://dx.doi.org

  13. Fiber optic systems for diode-pumped solid state lasers

    NASA Astrophysics Data System (ADS)

    Kozlov, Valery A.; Awad, H. R. I.; Vlasenko, Oleg A.; Zavartsev, Yury D.; Zagumennyi, Alexander I.; Studenikin, Pavel A.; Shcherbakov, Ivan A.; Gordova, M. R.; Kuznetsov, A. V.

    1996-03-01

    Radial nonsymmetrical fiber endface microlenses original fabrication technique has been used for high efficient pump laser diode radiation coupling (up to 93% without AR coating) into the standard optical fibers and for the form of a pump power diagram at the output fiber endfaces. Nd:GdVO4 laser (2.5 mm crystals length) parameters with semiconfocal (output mirror curvature radius 10 cm) and monolith plane mirrors cavities have been measured for different pump diagrams formed by plane endfaces, spherical microlenses, and Selfoc lenses. Compact diode-pumped solid state lasers may be used in optical communications, optical storage, medicine, and other applications. Diode laser (DL)-optical fiber coupling gives several advantages for these pumping systems -- a possibility to combine several DLs radiation, a remote DLs mounting, small size and electrical safety of the laser heads, simple schemes of active crystals cooling, axial symmetry of the pumping beam for longitudinal geometry. In general, high coupling efficiency between a semiconductor light source and optical fiber may be achieved by the use of microlens, formed on the endface of the fiber. In this case bulk optical components between DL and optical fiber are not needed. In addition, the only reflection surface exists in this coupling technique. Different techniques for producing microlenses on a fiber endface have been developed. For example, tapered hemispherical lenses, melted, etched, and polished lenses are commonly used for this coupling. However, all types of such techniques produce in general radial symmetry lenses: therefore, they do not provide efficient coupling between a round fiber core and a nonsymmetrical DL's radiation. In this paper we demonstrate the fabrication technique of fiber endface radial nonsymmetrical microlenses with radii curvature from few micrometers to few tens micrometers by grinding/polishing process. This process may be used for producing different nonspherical microlenses

  14. Optical Phase Locking of Modelocked Lasers for Particle Accelerators

    SciTech Connect

    Plettner, T.; Sinha, S.; Wisdom, J.; Colby, E.R.; /SLAC

    2006-02-17

    Particle accelerators require precise phase control of the electric field through the entire accelerator structure. Thus a future laser driven particle accelerator will require optical synchronism between the high-peak power laser sources that power the accelerator. The precise laser architecture for a laser driven particle accelerator is not determined yet, however it is clear that the ability to phase-lock independent modelocked oscillators will be of crucial importance. We report the present status on our work to demonstrate long term phaselocking between two modelocked lasers to within one degree of optical phase and describe the optical synchronization techniques that we employ.

  15. Applications of Adaptive Optics Scanning Laser Ophthalmoscopy

    PubMed Central

    Roorda, Austin

    2010-01-01

    Adaptive optics (AO) describes a set of tools to correct or control aberrations in any optical system. In the eye, AO allows for precise control of the ocular aberrations. If used to correct aberrations over a large pupil, for example, cellular level resolution in retinal images can be achieved. AO systems have been demonstrated for advanced ophthalmoscopy as well as for testing and/or improving vision. In fact, AO can be integrated to any ophthalmic instrument where the optics of the eye is involved, with a scope of applications ranging from phoropters to optical coherence tomography systems. In this paper, I discuss the applications and advantages of using AO in a specific system, the adaptive optics scanning laser ophthalmoscope, or AOSLO. Since the Borish award was, in part, awarded to me because of this effort, I felt it appropriate to select this as the topic for this paper. Furthermore, users of AOSLO continue to appreciate the benefits of the technology, some of which were not anticipated at the time of development, and so it is time to revisit this topic and summarize them in a single paper. PMID:20160657

  16. ARTICLES: Coumarin 6 as the active medium of a dye vapor laser with wide-band optical pumping and specific characteristics of such lasers

    NASA Astrophysics Data System (ADS)

    Trusov, K. K.

    1982-11-01

    An experimental investigation was made of the efficiency of conversion of flashlamp pump radiation to fluorescence of coumarin 6 at a buffer gas pressure of 0-1 MPa. The lasing dynamics of the flashlamppumped vapor of this compound was also studied. It was found that the fluorescence quantum efficiency averaged over the absorption spectrum, which characterized the pump conversion efficiency, was langηrang<=0.3 at a buffer gas pressure of 0-1 MPa. Dependences of langηrang and the rate constant for optical bleaching of the dye on the buffer gas pressure were determined. A comparative analysis of the lasing dynamics of coumarin 6 in vapors and in an ether solution showed that the gas phase had a higher lasing threshold (18-20 times higher) and a larger increment of loss growth in the spectral range of lasing (four times higher). It also had a shorter maximum lasing duration (tmaxapprox500 nsec).

  17. COMPUTER MODEL OF TEMPERATURE DISTRIBUTION IN OPTICALLY PUMPED LASER RODS

    NASA Technical Reports Server (NTRS)

    Farrukh, U. O.

    1994-01-01

    Managing the thermal energy that accumulates within a solid-state laser material under active pumping is of critical importance in the design of laser systems. Earlier models that calculated the temperature distribution in laser rods were single dimensional and assumed laser rods of infinite length. This program presents a new model which solves the temperature distribution problem for finite dimensional laser rods and calculates both the radial and axial components of temperature distribution in these rods. The modeled rod is either side-pumped or end-pumped by a continuous or a single pulse pump beam. (At the present time, the model cannot handle a multiple pulsed pump source.) The optical axis is assumed to be along the axis of the rod. The program also assumes that it is possible to cool different surfaces of the rod at different rates. The user defines the laser rod material characteristics, determines the types of cooling and pumping to be modeled, and selects the time frame desired via the input file. The program contains several self checking schemes to prevent overwriting memory blocks and to provide simple tracing of information in case of trouble. Output for the program consists of 1) an echo of the input file, 2) diffusion properties, radius and length, and time for each data block, 3) the radial increments from the center of the laser rod to the outer edge of the laser rod, and 4) the axial increments from the front of the laser rod to the other end of the rod. This program was written in Microsoft FORTRAN77 and implemented on a Tandon AT with a 287 math coprocessor. The program can also run on a VAX 750 mini-computer. It has a memory requirement of about 147 KB and was developed in 1989.

  18. Laser camp: shining a light on optics careers

    NASA Astrophysics Data System (ADS)

    Donnelly, Judith; Goyette, Donna; Magnani, Nancy; Wosczyna-Birch, Karen

    2008-08-01

    Three Rivers Community College offers two associate degree programs in optics/photonics, and graduates have their choice of jobs in New England and across the United States. Nonetheless, students, their parents, teachers and guidance counselors are largely unaware of the career opportunities in the photonics industry. To promote optics/photonics career awareness, we hosted two versions of "Laser Camp" in 2007 and 2008. Hands-on activities were chosen to promote awareness of optical science and technology careers and to provide "take home" information and souvenirs to share with family and friends. In this paper, we discuss the logistics of funding, marketing, permissions, transportation and food service and share our student-tested activities.

  19. Statistical optics applied to high-power glass lasers

    SciTech Connect

    Manes, K.R.; Simmons, W.W.

    1985-04-01

    Multiterawatt laser systems, particularly the Novette system at the Lawrence Livermore National Laboratory, are simulated using statistical-optics techniques. The results are compared with experimental observations.

  20. Precision Spectroscopy, Diode Lasers, and Optical Frequency Measurement Technology

    NASA Technical Reports Server (NTRS)

    Hollberg, Leo (Editor); Fox, Richard (Editor); Waltman, Steve (Editor); Robinson, Hugh

    1998-01-01

    This compilation is a selected set of reprints from the Optical Frequency Measurement Group of the Time and Frequency Division of the National Institute of Standards and Technology, and consists of work published between 1987 and 1997. The two main programs represented here are (1) development of tunable diode-laser technology for scientific applications and precision measurements, and (2) research toward the goal of realizing optical-frequency measurements and synthesis. The papers are organized chronologically in five, somewhat arbitrarily chosen categories: Diode Laser Technology, Tunable Laser Systems, Laser Spectroscopy, Optical Synthesis and Extended Wavelength Coverage, and Multi-Photon Interactions and Optical Coherences.

  1. Optical reprogramming with ultrashort femtosecond laser pulses

    NASA Astrophysics Data System (ADS)

    Uchugonova, Aisada; Breunig, Hans G.; Batista, Ana; König, Karsten

    2015-03-01

    The use of sub-15 femtosecond laser pulses in stem cell research is explored with particular emphasis on the optical reprogramming of somatic cells. The reprogramming of somatic cells into induced pluripotent stem (iPS) cells can be evoked through the ectopic expression of defined transcription factors. Conventional approaches utilize retro/lenti-viruses to deliver genes/transcription factors as well as to facilitate the integration of transcription factors into that of the host genome. However, the use of viruses may result in insertional mutations caused by the random integration of genes and as a result, this may limit the use within clinical applications due to the risk of the formation of cancer. In this study, a new approach is demonstrated in realizing non-viral reprogramming through the use of ultrashort laser pulses, to introduce transcription factors into the cell so as to generate iPS cells.

  2. Unstable behavior of lasers and other optical systems

    NASA Astrophysics Data System (ADS)

    Narducci, L. N.; Tredicce, J. R.; Yuan, J. M.; Abraham, N. B.

    1987-11-01

    This final report summarizes the theoretical and experimental activities carried out jointly by the Qauntum Optics Group at Drexel University and the Nonlinear Dynamics and Laser Physics Group at Bryn Mawr College during the period October 15, 1985 to August 31, 1987. The report includes detailed reviews of our major findings in the study of laser dynamics, especially theoretically, but also experimentally, and summaries of other parallel studies on Stimulated Raman Scattering (SRS) and nonlinear dynamics. Our emphasis has been on the formulation of a generalized version of the Maxwell-Bloch equations for the laser to include transverse degrees of freedom. We have succeeded in developing this model and have investigated in detail its steady state and linear stability properties. Our main result is the discovery of low threshold unstable behaviors and the identification of their physical origin.

  3. Open-ended projects in undergraduate optics and lasers courses

    NASA Astrophysics Data System (ADS)

    Hoyt, Chad

    This talk will describe the format and experience of undergraduate Lasers and Optics courses at Bethel University. The courses, which include a rigorous lecture portion, are built on open-ended research projects that have a novel aspect. They begin with four weeks of small student groups rotating between several standard laser and optics laboratory exercises. These may include, for example, alignment and characterization of a helium neon laser and measurements with a Michelson interferometer or a scanning Fabry-Pérot optical cavity. During the following seven weeks of the course, student groups (2-4 people) choose and pursue research questions in the lab. Their work culminates in a group manuscript typeset in and a twenty-minute presentation to the class. Projects in the spring, 2014 Optics course included experiments with ultracold lithium atoms in a magneto-optical trap, optical tweezers, digital holography and adaptive optics. Projects in the spring, 2015 Lasers course included ultrafast optics with a mode-locked erbium fiber laser, quantum optics, surface plasmon lasers (led by Nathan Lindquist) and a low-cost, near-infrared spectrometer. Several of these projects are related to larger scale, funded research in the physics department. The format and experience in Lasers and Optics is representative of other upper-level courses at Bethel, including Fluid Mechanics and Computer Methods. A physics education research group from the University of Colorado evaluated the spring, 2015 Lasers course. They focused on student experimental attitudes and measurements of student project ownership.

  4. Optical Material Researches for Frontier Optical Ceramics and Visible Fiber Laser Technologies

    DTIC Science & Technology

    2016-07-07

    AFRL-AFOSR-JP-TR-2016-0059 Optical material researches for frontier optical ceramics and visible fiber laser technologies Yasushi Fujimoto Osaka...07-2016 2. REPORT TYPE Final 3. DATES COVERED (From - To) 18 Apr 2013 to 17 Apr 2016 4. TITLE AND SUBTITLE Optical material researches for frontier...are very useful for scientific and industrial applications. 15. SUBJECT TERMS Fibre Lasers, Laser Dynamics, Nonlinear Optical Materials 16. SECURITY

  5. Optical penetration sensor for pulsed laser welding

    DOEpatents

    Essien, Marcelino; Keicher, David M.; Schlienger, M. Eric; Jellison, James L.

    2000-01-01

    An apparatus and method for determining the penetration of the weld pool created from pulsed laser welding and more particularly to an apparatus and method of utilizing an optical technique to monitor the weld vaporization plume velocity to determine the depth of penetration. A light source directs a beam through a vaporization plume above a weld pool, wherein the plume changes the intensity of the beam, allowing determination of the velocity of the plume. From the velocity of the plume, the depth of the weld is determined.

  6. Optical Alignment Device For Laser Communication

    NASA Technical Reports Server (NTRS)

    Casey, William L.

    1988-01-01

    Optical alignment device under development enables continuous tracking and coalignment of two beams of light. Intended primarily for laser-communication station, in which transmitted beam must be aligned with received beam to ensure transmitted beam falls on receiver at other station. Expected to consume less power and be smaller and less complicated than alignment shutter and drive previously used. Prism and filter separate two overlapping collimated light beams of different wavelength or polarization. Coordinates of two beams tracked on charge-coupled device to determine degree of directional misalignment between two beams.

  7. Coumarin 6 as the active medium of a dye vapor laser with wide-band optical pumping and specific characteristics of such lasers

    SciTech Connect

    Trusov, K.K.

    1982-11-01

    An experimental investigation was made of the efficiency of conversion of flashlamp pump radiation to fluorescence of coumarin 6 at a buffer gas pressure of 0--1 MPa. The lasing dynamics of the flashlamp-pumped vapor of this compound was also studied. It was found that the fluorescence quantum efficiency averaged over the absorption spectrum, which characterized the pump conversion efficiency, was < or =0.3 at a buffer gas pressure of 0--1 MPa. Dependences of and the rate constant for optical bleaching of the dye on the buffer gas pressure were determined. A comparative analysis of the lasing dynamics of coumarin 6 in vapors and in an ether solution showed that the gas phase had a higher lasing threshold (18--20 times higher) and a larger increment of loss growth in the spectral range of lasing (four times higher). It also had a shorter maximum lasing duration (t/sub max/roughly-equal500 nsec).

  8. Study of the possibility of developing a multichannel-diode-pumped multikilowatt solid-state laser based on optically dense active media

    SciTech Connect

    Garnov, S V; Mikhailov, V A; Serov, R V; Smirnov, V A; Tsvetkov, V B; Shcherbakov, I A

    2007-10-31

    Optimal conditions are determined for the development of efficient diode-pumped 1-{mu}m solid-state lasers with output powers up to a few tens of kilowatts. The thermal operating conditions are analysed for various Yb{sup 3+}- or Nd{sup 3+}-doped active media used in high-power laser systems. The advantages and disadvantages of these active ions and various crystal matrices are discussed. The theoretical analysis and experimental simulations allow one to determine the application fields of various laser crystals. A new concept of a multibeam (multipoint) pumping of active media is proposed. (special issue devoted to the 25th anniversary of the a.m. prokhorov general physics institute)

  9. Actively mode-locked Raman fiber laser.

    PubMed

    Yang, Xuezong; Zhang, Lei; Jiang, Huawei; Fan, Tingwei; Feng, Yan

    2015-07-27

    Active mode-locking of Raman fiber laser is experimentally investigated for the first time. An all fiber connected and polarization maintaining loop cavity of ~500 m long is pumped by a linearly polarized 1120 nm Yb fiber laser and modulated by an acousto-optic modulator. Stable 2 ns width pulse train at 1178 nm is obtained with modulator opening time of > 50 ns. At higher power, pulses become longer, and second order Raman Stokes could take place, which however can be suppressed by adjusting the open time and modulation frequency. Transient pulse evolution measurement confirms the absence of relaxation oscillation in Raman fiber laser. Tuning of repetition rate from 392 kHz to 31.37 MHz is obtained with harmonic mode locking.

  10. High-efficiency Autonomous Laser Adaptive Optics

    NASA Astrophysics Data System (ADS)

    Baranec, Christoph; Riddle, Reed; Law, Nicholas M.; Ramaprakash, A. N.; Tendulkar, Shriharsh; Hogstrom, Kristina; Bui, Khanh; Burse, Mahesh; Chordia, Pravin; Das, Hillol; Dekany, Richard; Kulkarni, Shrinivas; Punnadi, Sujit

    2014-07-01

    As new large-scale astronomical surveys greatly increase the number of objects targeted and discoveries made, the requirement for efficient follow-up observations is crucial. Adaptive optics imaging, which compensates for the image-blurring effects of Earth's turbulent atmosphere, is essential for these surveys, but the scarcity, complexity and high demand of current systems limit their availability for following up large numbers of targets. To address this need, we have engineered and implemented Robo-AO, a fully autonomous laser adaptive optics and imaging system that routinely images over 200 objects per night with an acuity 10 times sharper at visible wavelengths than typically possible from the ground. By greatly improving the angular resolution, sensitivity, and efficiency of 1-3 m class telescopes, we have eliminated a major obstacle in the follow-up of the discoveries from current and future large astronomical surveys.

  11. HIGH-EFFICIENCY AUTONOMOUS LASER ADAPTIVE OPTICS

    SciTech Connect

    Baranec, Christoph; Riddle, Reed; Tendulkar, Shriharsh; Hogstrom, Kristina; Bui, Khanh; Dekany, Richard; Kulkarni, Shrinivas; Law, Nicholas M.; Ramaprakash, A. N.; Burse, Mahesh; Chordia, Pravin; Das, Hillol; Punnadi, Sujit

    2014-07-20

    As new large-scale astronomical surveys greatly increase the number of objects targeted and discoveries made, the requirement for efficient follow-up observations is crucial. Adaptive optics imaging, which compensates for the image-blurring effects of Earth's turbulent atmosphere, is essential for these surveys, but the scarcity, complexity and high demand of current systems limit their availability for following up large numbers of targets. To address this need, we have engineered and implemented Robo-AO, a fully autonomous laser adaptive optics and imaging system that routinely images over 200 objects per night with an acuity 10 times sharper at visible wavelengths than typically possible from the ground. By greatly improving the angular resolution, sensitivity, and efficiency of 1-3 m class telescopes, we have eliminated a major obstacle in the follow-up of the discoveries from current and future large astronomical surveys.

  12. CO2 laser and plasma microjet process for improving laser optics

    DOEpatents

    Brusasco, Raymond M.; Penetrante, Bernardino M.; Butler, James A.; Grundler, Walter; Governo, George K.

    2003-09-16

    A optic is produced for operation at the fundamental Nd:YAG laser wavelength of 1.06 micrometers through the tripled Nd:YAG laser wavelength of 355 nanometers by the method of reducing or eliminating the growth of laser damage sites in the optics by processing the optics to stop damage in the optics from growing to a predetermined critical size. A system is provided of mitigating the growth of laser-induced damage in optics by virtue of very localized removal of glass and absorbing material.

  13. On-chip optical detection of laser cooled atoms.

    PubMed

    Quinto-Su, P; Tscherneck, M; Holmes, M; Bigelow, N

    2004-10-18

    We have used an optical fiber based system to implement optical detection of atoms trapped on a reflective "atom-chip". A fiber pair forms an emitter-detector setup that is bonded to the atom-chip surface to optically detect and probe laser cooled atoms trapped in a surface magneto-optical trap. We demonstrate the utility of this scheme by measuring the linewidth of the Cs D2 line at different laser intensities.

  14. Feedback and Acousto Optic Isolation Effects on Laser Stability.

    DTIC Science & Technology

    1977-03-01

    This paper analyzes the effect of optical feedback on laser frequency stability and the acousto optic isolator concept, which was demonstrated...nonlinearity such as saturation in the laser medium. The analysis mathematically corroborates the initial acousto optic isolator concept and the...limited experimental data available. In the study of the acousto optic isolator, it was determined that an acceptable analytic expression for the

  15. On-chip optical detection of laser cooled atoms

    NASA Astrophysics Data System (ADS)

    Quinto-Su, P. A.; Tscherneck, M.; Holmes, M.; Bigelow, N. P.

    2004-10-01

    We have used an optical fiber based system to implement optical detection of atoms trapped on a reflective "atom-chip". A fiber pair forms an emitter-detector setup that is bonded to the atom-chip surface to optically detect and probe laser cooled atoms trapped in a surface magneto-optical trap. We demonstrate the utility of this scheme by measuring the linewidth of the Cs D2 line at different laser intensities.

  16. Monitoring of laser welding process by optical emission spectroscopy

    NASA Astrophysics Data System (ADS)

    Bruncko, Jaroslav; Uherek, Frantisek; Michalka, Miroslav

    2003-07-01

    Technological processes including laser welding that use a laser beam are typically accompanied with the occurrence of laser-induced plasma. This physical phenomenon is investigated by many different monitoring methods and optical emission spectroscopy is the most common. The recent advert of miniature fibre optic spectrometers and relative cheap and powerful computers has provided a very promising tool for on-line spectral analyzing of laser-induced plasma. The contribution deals with the on-line monitoring of a laser-induced plasma during laser beam welding by optical emission spectroscopy. In this study a continuous-wave CO2 laser with output power up to 3 kW was used. Circumstances of partial and full penetration of welded specimen material and the relation with spectroscopic parameters of laser-induced plasma were investigated.

  17. Performance of laser based optical imaging system

    NASA Astrophysics Data System (ADS)

    Shah, Dhrupesh S.; Banerjee, Arup; Vora, Anup; Biswas, Amiya; Patel, Naimesh; Kurulkar, Amit; Dutt, Ashutosh

    2016-05-01

    Day night imaging application requires high dynamic range optical imaging system to detect targets of interest covering mid-day (>32000 Lux)[1], and moonless night ( 1mLux)[1] under clear sky- (visibility of >10km, atmospheric loss of <1dB/km) and hazy (visibility of >500m, atmospheric loss of >15dB/Km) conditions. Major governing factors for development of such camera systems are (i) covert imaging with ability to identify the target, (ii) imaging irrespective to the scene background, (iii) reliable operation , (iv) imaging capabilities in inclement weather conditions, (v) resource requirement vs availability power & mass, (vi) real-time data processing, (vii) self-calibration, and (viii) cost. Identification of optimum spectral band of interest is most important to meet these requirements. Conventional detection systems sensing in MWIR and LWIR band has certain draw backs in terms of target detection capabilities, susceptibility to background and huge thermo-mechanical resource requirement. Alternatively, range gated imaging camera system sensing in NIR/SWIR spectrum has shown significant potential to detect wide dynamic range targets. ToF Camera configured in NIR band has certain advantages in terms of Focal Plane Assembly (FPA) development with large format detectors and thermo-mechanical resource requirement compared to SWIR band camera configuration. In past, ToF camera systems were successfully configured in NIR spectrum using silicon based Electron Multiplying CCD (EMCCD), Intensifier CCD (ICCD) along with Gating device and pulsed laser source having emission in between 800nm to 900nm. However, these systems have a very low dynamic range and not suitable for clear sky mid-day conditions. Recently silicon based scientific grade CMOS image sensors have shown significant improvement in terms of high NIR responsivity and available in bigger formats (5MP or more), adequate Full well capacity for day time imaging (>30Ke), very low readout noise (<2e) required for

  18. Optical components for the Nova laser

    SciTech Connect

    Wallerstein, E.P.; Baker, P.C.; Brown, N.J.

    1982-05-17

    In addition to its other characteristics, the Nova Laser Fusion facility may well be the largest precision optical project ever undertaken. Moreover, during the course of construction, concurrent research and development has been successfully conducted, and has resulted in significant advances in various technical areas, including manufacturing efficiency. Although assembly of the first two beams of Nova is just commencing, the optical production, including construction of the special facilities required for many of the components, has been underway for over three years, and many phases of the optical manufacturing program for the first 10 beams will be completed within the next two years. On the other hand, new requirements for second and third harmonic generation have created the need to initiate new research and development. This work has been accomplished through the enormous cooperation DOE/LLNL has received from commercial industry on this project. In many cases, industry, where much of the optical component research and development and virtually all of the manufacturing is being done, has made substantial investment of its own funds in facilities, equipment, and research and development, in addition to those supplied by DOE/LLNL.

  19. Optically active quantum dots

    NASA Astrophysics Data System (ADS)

    Gerard, Valerie; Govan, Joseph; Loudon, Alexander; Baranov, Alexander V.; Fedorov, Anatoly V.; Gun'ko, Yurii K.

    2015-10-01

    The main goal of our research is to develop new types of technologically important optically active quantum dot (QD) based materials, study their properties and explore their biological applications. For the first time chiral II-VI QDs have been prepared by us using microwave induced heating with the racemic (Rac), D- and L-enantiomeric forms of penicillamine as stabilisers. Circular dichroism (CD) studies of these QDs have shown that D- and L-penicillamine stabilised particles produced mirror image CD spectra, while the particles prepared with a Rac mixture showed only a weak signal. It was also demonstrated that these QDs show very broad emission bands between 400 and 700 nm due to defects or trap states on the surfaces of the nanocrystals. These QDs have demonstrated highly specific chiral recognition of various biological species including aminoacids. The utilisation of chiral stabilisers also allowed the preparation of new water soluble white emitting CdS nano-tetrapods, which demonstrated circular dichroism in the band-edge region of the spectrum. Biological testing of chiral CdS nanotetrapods displayed a chiral bias for an uptake of the D- penicillamine stabilised nano-tetrapods by cancer cells. It is expected that this research will open new horizons in the chemistry of chiral nanomaterials and their application in nanobiotechnology, medicine and optical chemo- and bio-sensing.

  20. Resource Letter: LBOT-1: Laser-based optical tweezers.

    PubMed

    Lang, Matthew J; Block, Steven M

    2003-03-01

    This Resource Letter provides a guide to the literature on optical tweezers, also known as laser-based, gradient-force optical traps. Journal articles and books are cited for the following main topics: general papers on optical tweezers, trapping instrument design, optical detection methods, optical trapping theory, mechanical measurements, single molecule studies, and sections on biological motors, cellular measurements and additional applications of optical tweezers.

  1. Resource Letter: LBOT-1: Laser-based optical tweezers

    PubMed Central

    Lang, Matthew J.; Block, Steven M.

    2006-01-01

    This Resource Letter provides a guide to the literature on optical tweezers, also known as laser-based, gradient-force optical traps. Journal articles and books are cited for the following main topics: general papers on optical tweezers, trapping instrument design, optical detection methods, optical trapping theory, mechanical measurements, single molecule studies, and sections on biological motors, cellular measurements and additional applications of optical tweezers. PMID:16971965

  2. Detection and laser ranging of orbital objects using optical methods

    NASA Astrophysics Data System (ADS)

    Wagner, P.; Hampf, D.; Sproll, F.; Hasenohr, T.; Humbert, L.; Rodmann, J.; Riede, W.

    2016-09-01

    Laser ranging to satellites (SLR) in earth orbit is an established technology used for geodesy, fundamental science and precise orbit determination. A combined active and passive optical measurement system using a single telescope mount is presented which performs precise ranging measurements of retro reflector equipped objects in low earth orbit (LEO). The German Aerospace Center (DLR) runs an observatory in Stuttgart where a system has been assembled completely from commercial off-the-shelf (COTS) components. The visible light directed to the tracking camera is used to perform angular measurements of objects under investigation. This is done astrometrically by comparing the apparent target position with cataloged star positions. First successful satellite laser ranging was demonstrated recently using an optical fiber directing laser pulses onto the astronomical mount. The transmitter operates at a wavelength of 1064 nm with a repetition rate of 3 kHz and pulse energy of 25 μJ. A motorized tip/tilt mount allows beam steering of the collimated beam with μrad accuracy. The returning photons reflected from the object in space are captured with the tracking telescope. A special low aberration beam splitter unit was designed to separate the infrared from visible light. This allows passive optical closed loop tracking and operation of a single photon detector for time of flight measurements at a single telescope simultaneously. The presented innovative design yields to a compact and cost effective but very precise ranging system which allows orbit determination.

  3. Free-standing membrane polymer laser on the end of an optical fiber

    SciTech Connect

    Zhai, Tianrui E-mail: zhangxinping@bjut.edu.cn; Li, Songtao; Hu, Yujie; Wang, Yimeng; Wang, Li; Zhang, Xinping E-mail: zhangxinping@bjut.edu.cn; Chen, Li

    2016-01-25

    One- and two-dimensional distributed feedback cavities were constructed on free-standing polymer membranes using spin-coating and lift-off techniques. Low threshold lasing was generated through feedback amplification when the 290-nm membrane device was optically pumped, which was attributed to the strong confinement mechanism provided by the active waveguide layer without a substrate. The free-standing membrane polymer laser is flexible and can be transplanted. Single- and dual-wavelength fiber lasers were achieved by directly attaching the membrane polymer laser on the optical fiber end face. This technique provides potential to fabricate polymer lasers on surfaces with arbitrary shapes.

  4. Active optics simulation system

    NASA Technical Reports Server (NTRS)

    Chi, C. H.

    1973-01-01

    The active optics simulation system (AOSS) is a set of computer programs and associated software to be used in the development, design, and evaluation of a primary mirror control system for a large space telescope, (e.g., the tentatively proposed 3-meter telescope). The mathematical models of component subsystems and the solution of the physical processes that occur within the mirror surface control system were obtained, and based on these models AOSS simulates the behavior of the entire mirror surface control system as well as the behavior of the component subsystems. The program has a modular structure so that any subsystem module can be replaced or modified with minimum disruption of the rest of the simulation program.

  5. DBR-free optically pumped semiconductor disk lasers

    NASA Astrophysics Data System (ADS)

    Yang, Zhou; Albrecht, Alexander R.; Cederberg, Jeffrey G.; Sheik-Bahae, Mansoor

    2015-03-01

    Optically pumped semiconductor disk lasers (SDLs) provide high beam quality with high average-power power at designer wavelengths. However, material choices are limited by the need for a distributed Bragg reflector (DBR), usually monolithically integrated with the active region. We demonstrate DBR-free SDL active regions, which have been lifted off and bonded to various transparent substrates. For an InGaAs multi-quantum well sample bonded to a diamond window heat spreader, we achieved CW lasing with an output power of 2 W at 1150 nm with good beam quality.

  6. Optical diagnostics integrated with laser spark delivery system

    DOEpatents

    Yalin, Azer; Willson, Bryan; Defoort, Morgan; Joshi, Sachin; Reynolds, Adam

    2008-09-02

    A spark delivery system for generating a spark using a laser beam is provided, and includes a laser light source and a laser delivery assembly. The laser delivery assembly includes a hollow fiber and a launch assembly comprising launch focusing optics to input the laser beam in the hollow fiber. The laser delivery assembly further includes exit focusing optics that demagnify an exit beam of laser light from the hollow fiber, thereby increasing the intensity of the laser beam and creating a spark. Other embodiments use a fiber laser to generate a spark. Embodiments of the present invention may be used to create a spark in an engine. Yet other embodiments include collecting light from the spark or a flame resulting from the spark and conveying the light for diagnostics. Methods of using the spark delivery systems and diagnostic systems are provided.

  7. Scanning Optics Enabled Possibilities and Challenges in Laser Cladding

    NASA Astrophysics Data System (ADS)

    Pekkarinen, Joonas

    Laser cladding using a scanned beam is quite a similar process than laser cladding using static optics (e.g. lens or mirror optics). The main difference comes from the manipulation of the laser beam. In laser cladding with scanning optics the laser beam is manipulated with a scanner so that the laser's area of influence can be shaped numerically. This increases cladding process flexibility. Scanning optics enable laser beam modification considerably versatile way than normal static optics can. This is due to possibility of numerical adjustment of scanning amplitude, laser power and scanning frequency. By modifying these parameters clad beads geometry can by modified quite freely. However scanned laser beam in surface modification process creates some restricting factors to the process. Mainly limitations for the process parameter values come from the dual characteristics of the energy input. This paper treats usability of scanning optics in laser cladding process in general level. In this paper is discussed how scanned beam can be used to increase the flexibility but also maters that limit the usage of scanned beam in cladding process. Process possibilities and limitations are presented in trough experimental data and examples.

  8. CO.sub.2 optically pumped distributed feedback diode laser

    DOEpatents

    Rockwood, Stephen D.

    1980-01-01

    A diode laser optically pumped by a CO.sub.2 coherent source. Interference fringes generated by feeding the optical pumping beam against a second beam, periodically alter the reflectivity of the diode medium allowing frequency variation of the output signal by varying the impingent angle of the CO.sub.2 laser beams.

  9. Optically Pumped Subwavelength Lasers Operated at Room Temperature

    DTIC Science & Technology

    2012-05-06

    REPORT NACHOS Project Final Report_University of Michigan Optically pumped subwavelength lasers operated at room temperature 14. ABSTRACT 16. SECURITY...28-Feb-2011 NACHOS Project Final Report_University of Michigan Optically pumped subwavelength lasers operated at room temperature Report Title

  10. Optical system design and integration of the mercury laser altimeter.

    PubMed

    Ramos-Lzquierdo, Luis; Scott, V Stanley; Schmidt, Stephen; Britt, Jamie; Mamakos, William; Trunzo, Raymond; Cavanaugh, John; Miller, Roger

    2005-03-20

    The Mercury Laser Altimeter (MLA), developed for the 2004 MESSENGER mission to Mercury, is designed to measure the planet's topography by laser ranging. A description of the MLA optical system and its measured optical performance during instrument-level and spacecraft-level integration and testing are presented.

  11. Optical System Design and Integration of the Mercury Laser Altimeter

    NASA Technical Reports Server (NTRS)

    Ramos-Izquierdo, Luis; Scott, V. Stanley, III; Schmidt, Stephen; Britt, Jamie; Mamakos, William; Trunzo, Raymond; Cavanaugh, John; Miller, Roger

    2005-01-01

    The Mercury Laser Altimeter (MLA). developed for the 2004 MESSENGER mission to Mercury, is designed to measure the planet's topography via laser ranging. A description of the MLA optical system and its measured optical performance during instrument-level and spacecraft-level integration and testing are presented.

  12. LDEF active optical system components experiment

    NASA Technical Reports Server (NTRS)

    Blue, M. D.

    1991-01-01

    A preliminary report on the Active Optical System Components Experiment is presented. This experiment contained 136 components in a six-inch deep tray including lasers, infrared detectors and arrays, ultraviolet light detectors, light-emitting diodes, a light modulator, flash lamps, optical filters, glasses, and samples of surface finishes. The experimental results for those component characteristics appear as much related to the passage of time as to the effects of the space environment, but organic materials and extreme-infrared reflectivity of black paints show unexpected changes.

  13. Linear diode laser bar optical stretchers for cell deformation

    PubMed Central

    Sraj, Ihab; Marr, David W.M.; Eggleton, Charles D.

    2010-01-01

    To investigate the use of linear diode laser bars to optically stretch cells and measure their mechanical properties, we present numerical simulations using the immersed boundary method (IBM) coupled with classic ray optics. Cells are considered as three-dimensional (3D) spherical elastic capsules immersed in a fluid subjected to both optical and hydrodynamic forces in a periodic domain. We simulate cell deformation induced by both single and dual diode laser bar configurations and show that a single diode laser bar induces significant stretching but also induces cell translation of speed < 10 µm/sec for applied 6.6 mW/µm power in unconfined systems. The dual diode laser bar configuration, however, can be used to both stretch and optically trap cells at a fixed position. The net cell deformation was found to be a function of the total laser power and not the power distribution between single or dual diode laser bar configurations. PMID:21258483

  14. Demonstration of cascaded optical inverse free-electron laser accelerator.

    PubMed

    Dunning, M; Hemsing, E; Hast, C; Raubenheimer, T O; Weathersby, S; Xiang, D; Fu, F

    2013-06-14

    We report on a proof-of-principle demonstration of a two-stage cascaded optical inverse free-electron laser (IFEL) accelerator in which an electron beam is accelerated by a strong laser pulse after being packed into optical microbunches by a weaker initial laser pulse. We show experimentally that injection of precisely prepared optical microbunches into an IFEL allows net acceleration or deceleration of the beam, depending on the relative phase of the two laser pulses. The experimental results are in excellent agreement with simulation. The demonstrated technique holds great promise to significantly improve the beam quality of IFELs and may have a strong impact on emerging laser accelerators driven by high-power optical lasers.

  15. Demonstration of Cascaded Optical Inverse Free-Electron Laser Accelerator

    NASA Astrophysics Data System (ADS)

    Dunning, M.; Hemsing, E.; Hast, C.; Raubenheimer, T. O.; Weathersby, S.; Xiang, D.; Fu, F.

    2013-06-01

    We report on a proof-of-principle demonstration of a two-stage cascaded optical inverse free-electron laser (IFEL) accelerator in which an electron beam is accelerated by a strong laser pulse after being packed into optical microbunches by a weaker initial laser pulse. We show experimentally that injection of precisely prepared optical microbunches into an IFEL allows net acceleration or deceleration of the beam, depending on the relative phase of the two laser pulses. The experimental results are in excellent agreement with simulation. The demonstrated technique holds great promise to significantly improve the beam quality of IFELs and may have a strong impact on emerging laser accelerators driven by high-power optical lasers.

  16. Permanent laser conditioning of thin film optical materials

    DOEpatents

    Wolfe, C.R.; Kozlowski, M.R.; Campbell, J.H.; Staggs, M.; Rainer, F.

    1995-12-05

    The invention comprises a method for producing optical thin films with a high laser damage threshold and the resulting thin films. The laser damage threshold of the thin films is permanently increased by irradiating the thin films with a fluence below an unconditioned laser damage threshold. 9 figs.

  17. Permanent laser conditioning of thin film optical materials

    DOEpatents

    Wolfe, C. Robert; Kozlowski, Mark R.; Campbell, John H.; Staggs, Michael; Rainer, Frank

    1995-01-01

    The invention comprises a method for producing optical thin films with a high laser damage threshold and the resulting thin films. The laser damage threshold of the thin films is permanently increased by irradiating the thin films with a fluence below an unconditioned laser damage threshold.

  18. The Laser Level as an Optics Laboratory Tool

    NASA Astrophysics Data System (ADS)

    Kutzner, Mickey

    2013-12-01

    For decades now, the laser has been used as a handy device for performing ray traces in geometrical optics demonstrations and laboratories. , 2 For many ray- trace applications, I have found the laser level3 to be even more visually compelling and easy for student use than the laser pointer.

  19. The Laser Level as an Optics Laboratory Tool

    ERIC Educational Resources Information Center

    Kutzner, Mickey

    2013-01-01

    For decades now, the laser has been used as a handy device for performing ray traces in geometrical optics demonstrations and laboratories. For many ray- trace applications, I have found the laser level 3 to be even more visually compelling and easy for student use than the laser pointer.

  20. Fiber Optic Laser Delivery For Endarterectomy Of Experimental Atheromas

    NASA Astrophysics Data System (ADS)

    Eugene, John; Pollock, Marc E.; McColgan, Stephen J.; Hammer-Wilson, Marie; Berns, Michael W.

    1986-08-01

    Fiber optic delivery of argon ion laser energy and Nd-YAG laser energy were compared by the performance of open laser endarterectomy in the rabbit arteriosclerosis model. In Group I, 6 open laser endarterectomies were performed with an argon ion laser (488 nm and 514.5 nm) with the laser beam directed through a 400 pm quartz fiber optic. In Group II, 6 open laser endarterectomies were performed with a Nd-YAG laser (1.06 pm) with the laser beam directed through a 600 pm quartz fiber optic. Gross and light microscopic examination revealed smooth endarterectomy surfaces with tapered end points in Group I. In Group II, the endarterectomy surfaces were uneven and perforation occurred at 5/6 end points. Although energy could be precisely delivered with each laser by fiber optics, satisfactory results could only be achieved with the argon ion laser because argon ion energy was well absorbed by atheromas. Successful intravascular laser use requires a strong interaction between wavelength and atheroma as well as a precise delivery system.

  1. The Laser Level as an Optics Laboratory Tool

    ERIC Educational Resources Information Center

    Kutzner, Mickey

    2013-01-01

    For decades now, the laser has been used as a handy device for performing ray traces in geometrical optics demonstrations and laboratories. For many ray- trace applications, I have found the laser level 3 to be even more visually compelling and easy for student use than the laser pointer.

  2. Photonic muscles: optically controlled active optics

    NASA Astrophysics Data System (ADS)

    Ritter, Joe; Brozik, Jim; Basame, Solomon; Fallbach, Mike; Bradford, Larry; Douglas, Dennis; Miner, Gilda

    2005-08-01

    Reported is an investigation of a novel approach for producing and correcting active optical mirrors. Photoactive polymers represent a special class of "smart materials" whose electronic and physical properties such as conductivity, charge distribution, and especially shape can be changed in response to the environment (voltage, light, stress). The ability of photoactive polymers to change the structure of a polymer matrix in response to light is being studied to allow active figure control of membranes for optical element use. Photoactive substrates (mirrors) were produced. Incoherent light sources were used to effect shape control. Shack-Hartman Wavefront sensing was used to quantify the initial and optically altered figure of samples. Motion of two classes of samples was measured and is reported here. Proposed is also a new stress control technology as well as new hybrid technology combining two classes of photoactive materials.

  3. Robotic visible-light laser adaptive optics

    NASA Astrophysics Data System (ADS)

    Baranec, Christoph; Riddle, Reed; Law, Nicholas; Ramaprakash, A. N.; Tendulkar, Shriharsh; Bui, Khanh; Burse, Mahesh; Chordia, Pravin; Das, Hillol; Dekany, Richard; Kulkarni, Shrinivas; Punnadi, Sujit

    2013-12-01

    Robo-AO is the first autonomous laser adaptive optics system and science instrument operating on sky. With minimal human oversight, the system robotically executes large scale surveys, monitors long-term astrophysical dynamics and characterizes newly discovered transients, all at the visible diffraction limit. The adaptive optics setup time, from the end of the telescope slew to the beginning of an observation, is a mere ~50-60 s, enabling over 200 observations per night. The first of many envisioned systems has finished 58 nights of science observing at the Palomar Observatory 60-inch (1.5 m) telescope, with over 6,400 robotic observations executed thus far. The system will be augmented in late 2013 with a low-noise wide field infrared camera, which doubles as a tip-tilt sensor, to widen the spectral bandwidth of observations and increase available sky coverage while also enabling deeper visible imaging using adaptive-optics sharpened infrared tip-tilt guide sources. Techniques applicable to larger telescope systems will also be tested: the infrared camera will be used to demonstrate advanced multiple region-of-interest tip-tilt guiding methods, and a visitor instrument port will be used for evaluation of other instrumentation, e.g. single-mode and photonic fibers to feed compact spectrographs.

  4. Laser controlled atom source for optical clocks

    PubMed Central

    Kock, Ole; He, Wei; Świerad, Dariusz; Smith, Lyndsie; Hughes, Joshua; Bongs, Kai; Singh, Yeshpal

    2016-01-01

    Precision timekeeping has been a driving force in innovation, from defining agricultural seasons to atomic clocks enabling satellite navigation, broadband communication and high-speed trading. We are on the verge of a revolution in atomic timekeeping, where optical clocks promise an over thousand-fold improvement in stability and accuracy. However, complex setups and sensitivity to thermal radiation pose limitations to progress. Here we report on an atom source for a strontium optical lattice clock which circumvents these limitations. We demonstrate fast (sub 100 ms), cold and controlled emission of strontium atomic vapours from bulk strontium oxide irradiated by a simple low power diode laser. Our results demonstrate that millions of strontium atoms from the vapour can be captured in a magneto-optical trap (MOT). Our method enables over an order of magnitude reduction in scale of the apparatus. Future applications range from satellite clocks testing general relativity to portable clocks for inertial navigation systems and relativistic geodesy. PMID:27857214

  5. Predicting threshold and location of laser damage on optical surfaces

    DOEpatents

    Siekhaus, Wigbert

    1987-01-01

    An apparatus useful in the prediction of the damage threshold of various optical devices, the location of weak spots on such devices and the location, identification, and elimination of optical surface impurities comprising, a focused and pulsed laser, an photo electric detector/imaging means, and a timer. The weak spots emit photoelectrons when subjected to laser intensities that are less than the intensity actually required to produce the damage. The weak spots may be eliminated by sustained exposure to the laser beam.

  6. Optically-Based Diagnostics for Gas-Phase Laser Development

    DTIC Science & Technology

    2010-08-01

    Phase Laser Development Acknowledgement of Support and Disclaimer This material is based upon work supported by Air Force Office of Scientific...00-2010 4. TITLE AND SUBTITLE Optically-Based Diagnostics for Gas-Phase Laser Development 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM...Sciences Inc. Role of Optical Diagnostics in High Energy Gas Laser Development  Chemically rich, energetic, reacting flow with competing phenomena

  7. Optical antenna in laser inter-satellite communication

    NASA Astrophysics Data System (ADS)

    Wen, Chuanhua; Wang, Chunxia; Li, Yuquan

    2005-02-01

    In the modern world of telecommunications, the concept of wireless global coverage is of the utmost importance. However, real global coverage can only be achieved by satellite systems. Satellites communication is the most important mean of the communication network. The traditional satellites communication and inter-satellites links are built by microwave. In recent years, laser links for inter-satellites communication are becoming more and more important. Laser communication systems operate in a frequency range above the regulated spectrum. Laser provides many advantages for using in point-to-point ISLs (inter-satellites links) such as for links between satellites and spacecraft in deep space. Such advantages include: high speed; high bandwidth; small antenna size; narrow field of view; and narrow antenna beam. These advantages combined with the advantages in fiber optic components (optical preamplifiers, multiplexers, detectors, etc) have made laser attractive for laser links. Now we can bring WDM (wavelength-division multiplexing) to emerging broadband satellite communication systems. By using the common antenna system and ATP (Aiming, Tracking and Pointing) system, the satellites will get more capacity. In the inter-satellites laser communication, the important performances of the systems such as BER and BL both have direct relation with the optical systems. The optical systems have the function of ATP. The optical antenna is the most important component of the optical system. So the optical antenna is an important key technology to the inter-satellites laser communication. In this paper, we mainly study the optical system in the inter-satellites laser communication. we compare with three kinds of optical antennas: refractor and reflector and Catadioptrics of the passive optical system; we also analyze the effect of bandwidth to the WDM communication systems; we use the correlative software, simulate the curves of the performance of the optical antennas. These

  8. Use of optical skin phantoms for calibration of dermatological lasers

    NASA Astrophysics Data System (ADS)

    Wróbel, M. S.; Sekowska, A.; Marchwiński, M.; Galla, S.; Cenian, A.

    2016-09-01

    A wide range of dermatological diseases can be efficiently treated using laser heating. Nevertheless, before the new laser is introduced into clinical practice, its parameters and ability to interact with human skin have to be carefully examined. In order to do that optical skin phantoms can be used. Such phantoms closely imitate the scattering and absorption properties of real human skin tissue along with its thermal properties, such as capacitance and conductivity specific heat. We have fabricated a range of optical tissue phantoms based on polyvinylchloride-plastisol PVC-P with varying optical properties, including the absorption, scattering and density of the matrix material. We have utilized a pre-clinical dermatological laser system with a 975 nm diode laser module. A range of laser settings were tested, such as laser pulse duration, laser power and number of pulses. We have studied laser irradiation efficiency on fabricated optical tissue phantoms. Measurements of the temporal and spatial temperature distribution on the phantoms' surface were performed using thermographic imaging. The comparison of results between tissues' and phantoms' optical and thermal response prove that they can be used for approximate evaluation of laser heating efficiency. This study presents a viable approach for calibration of dermatological lasers which can be utilized in practice.

  9. Advances in lasers and optical micro-nano-systems

    NASA Astrophysics Data System (ADS)

    Laurell, F.; Fazio, E.

    2010-09-01

    Lasers represent a well consolidated technology: nevertheless, research in this field remains very active and productive, in both basic and applied directions. At the moment significant attention is given to those sources that bring together high power and compactness. Such high power lasers find important applications for material treatments and such applications are presented by Ehsani et al and Saiedeh Saghafi et al, in the treatment of dielectric thin films (Alteration of optical and morphological properties of polycarbonate illuminated by visible/IR laser beams) or of biological tissues like pistachio seeds (Investigating the effects of laser beams (532 and 660 nm) in annihilation of pistachio mould fungus using spectrophotometry analysis). In particular the latter paper show how laser sources can find very important applications in new domains, preserving goods and food without the need for preservatives or pesticides by simply sterilizing them using light. Optical Micro and Nano Systems presents a new domain for exploration. In this framework this special issue is very attractive, because it assembles papers reporting new results in three directions: new techniques for monitoring integrated micro- and nano-systems, new integrated systems and novel high performance metamaterial configurations. Integrated micro-components can be monitored and controlled using reflectance measurements as presented by Piombini et al (Toward the reflectance measurement of micro components). Speckle formation during laser beam reflection can also be a very sophisticated tool for detecting ultra-precise displacements, as presented by Filter et al (High resolution displacement detection with speckles : accuracy limits in linear displacement speckle metrology). Three dimensional integrated optical structures is indeed a big challenge and a peculiarity of photonics, they can be formed through traditional holography or using more sophisticated and novel ! technologies. Thus, special

  10. Influence of laser beam characteristics and focusing optics on optical laser-induced breakdown detection

    NASA Astrophysics Data System (ADS)

    Walther, C.; Hauser, W.

    2009-12-01

    Laser-induced breakdown detection (LIBD) is a well established technique for measuring size and concentration of inorganic colloids in liquids. However, most applications of LIBD are restricted to the measurement of mean sizes, which is problematic in cases of wide colloid size distributions (PSD) as typically is the case in natural systems. Evaluation of PSDs from LIBD is possible but requires detailed control of the power density within the laser focus. In the present work we describe the mathematical treatment how to calculate this power density from the beam characteristics of the light source and the optical properties of the focusing optics. The results are compared to measured spatial distributions of breakdown events of three LIBD setups.

  11. Femtosecond laser processing of optical fibres for novel sensor development

    NASA Astrophysics Data System (ADS)

    Kalli, Kyriacos; Theodosiou, Antreas; Ioannou, Andreas; Lacraz, Amedee

    2017-04-01

    We present results of recent research where we have utilized a femtosecond laser to micro-structure silica and polymer optical fibres in order to realize versatile optical components such as diffractive optical elements on the fibre end face, the inscription of integrated waveguide circuits in the fibre cladding and novel optical fibre sensors designs based on Bragg gratings in the core. A major hurdle in tailoring or modifying the properties of optical fibres is the development of an inscription method that can prove to be a flexible and reliable process that is generally applicable to all optical fibre types; this requires careful matching of the laser parameters and optics in order to examine the spatial limits of direct laser writing, whether the application is structuring at the surface of the optical fibre or inscription in the core and cladding of the fibre. We demonstrate a variety of optical components such as two-dimensional grating structures, Bessel, Airy and vortex beam generators; moreover, optical bridging waveguides inscribed in the cladding of single-mode fibre as a means to selectively couple light from single-core to multi-core optical fibres, and demonstrate a grating based sensor; finally, we have developed a novel femtosecond laser inscription method for the precise inscription of tailored Bragg grating sensors in silica and polymer optical fibres. We also show that this novel fibre Bragg grating inscription technique can be used to modify and add versatility to an existing, encapsulated optical fibre pressure sensor.

  12. Laser-Induced Heating in Optical Traps

    PubMed Central

    Peterman, Erwin J. G.; Gittes, Frederick; Schmidt, Christoph F.

    2003-01-01

    In an optical tweezers experiment intense laser light is tightly focused to intensities of MW/cm2 in order to apply forces to submicron particles or to measure mechanical properties of macromolecules. It is important to quantify potentially harmful or misleading heating effects due to the high light intensities in biophysical experiments. We present a model that incorporates the geometry of the experiment in a physically correct manner, including heat generation by light absorption in the neighborhood of the focus, balanced by outward heat flow, and heat sinking by the glass surfaces of the sample chamber. This is in contrast to the earlier simple models assuming heat generation in the trapped particle only. We find that in the most common experimental circumstances, using micron-sized polystyrene or silica beads, absorption of the laser light in the solvent around the trapped particle, not in the particle itself, is the most important contribution to heating. To validate our model we measured the spectrum of the Brownian motion of trapped beads in water and in glycerol as a function of the trapping laser intensity. Heating both increases the thermal motion of the bead and decreases the viscosity of the medium. We measured that the temperature in the focus increased by 34.2 ± 0.1 K/W with 1064-nm laser light for 2200-nm-diameter polystyrene beads in glycerol, 43.8 ± 2.2 K/W for 840-nm polystyrene beads in glycerol, 41.1 ± 0.7 K/W for 502-nm polystyrene beads in glycerol, and 7.7 ± 1.2 K/W for 500-nm silica beads and 8.1 ± 2.1 K/W for 444-nm silica beads in water. Furthermore, we observed that in glycerol the heating effect increased when the bead was trapped further away from the cover glass/glycerol interface as predicted by the model. We show that even though the heating effect in water is rather small it can have non-negligible effects on trap calibration in typical biophysical experimental circumstances and should be taken into consideration when laser

  13. Laser-based study of geometrical optics at school level

    NASA Astrophysics Data System (ADS)

    Garg, Amit; Dhingra, Vishal; Sharma, Reena; Mittal, Ankit; Tiwadi, Raman; Chakravarty, Pratik

    2011-10-01

    Students at the school level from grade 7 to 12 are taught various concepts of geometrical optics but with little hands-on activities. Light propagation through different media, image formation using lenses and mirrors under different conditions and application of basic principles to characterization of lenses, mirrors and other instruments has been a subject which although fascinates students but due to lack of suitable demonstrating setups, students find difficulty in understanding these concepts and hence unable to appreciate the importance of such concepts in various useful scientific apparatus, day to day life, instruments and devices. Therefore, students tend to cram various concepts related to geometrical optics instead of understanding them. As part of the extension activity in the University Grants Commission major research project "Investigating science hands-on to promote innovation and research at undergraduate level" and University of Delhi at Acharya Narendra Dev College SPIE student chapter, students working under this optics outreach programme have demonstrated various experiments on geometrical optics using a five beam laser ray box and various optical components like different types of mirrors, lenses, prisms, optical fibers etc. The various hands-on activities includes demonstrations on laws of reflection, image formation using plane, concave and convex mirrors, mirror formula, total internal reflection, light propagation in an optical fiber, laws of refraction, image formation using concave and convex lenses and combination of these lenses, lens formula, light propagation through prisms, dispersion in prism, defects in eye- Myopia and hypermetropia. Subjects have been evaluated through pre and post tests in order to measure the improvement in their level of understanding.

  14. Advanced Laser Chemical Processing For Microelectronics and Integrated Optics

    DTIC Science & Technology

    1992-08-15

    Barbara, CA (June 25-27, 1990). 15. R.M. Osgood, Jr., " Laser - Fabrication for Integrated Electronics and Optics," OITDA Conference, Tokyo, Japan, (July 5...Society Meeting, Boston, MA, November 26 - December 3, 1990. 20. R.M. Osgood, Jr., "Advances in Laser Fabrication for Solid-State Electronics and...Thin, Excimer Laser-Deposited Cd Interlayers," J. Elec. Mat. 12, 1239 (July, 1990). 14. R.M. Osgood, Jr., " Laser - Fabrication for Solid State

  15. Nonlinear optics with coherent free electron lasers

    NASA Astrophysics Data System (ADS)

    Bencivenga, F.; Capotondi, F.; Mincigrucci, R.; Cucini, R.; Manfredda, M.; Pedersoli, E.; Principi, E.; Simoncig, A.; Masciovecchio, C.

    2016-12-01

    We interpreted the recent construction of free electron laser (FELs) facilities worldwide as an unprecedented opportunity to bring concepts and methods from the scientific community working with optical lasers into the domain of x-ray science. This motivated our efforts towards the realization of FEL-based wave-mixing applications. In this article we present new extreme ultraviolet transient grating (X-TG) data from vitreous SiO2, collected using two crossed FEL pulses (photon frequency 38 eV) to generate the X-TG and a phase matched optical probing pulse (photon frequency 3.1 eV). This experiment extends our previous investigation, which was carried out on a nominally identical sample using a different FEL photon frequency (45 eV) to excite the X-TG. The present data are featured by a peak intensity of the X-TG signal substantially larger than that previously reported and by slower modulations of the X-TG signal at positive delays. These differences could be ascribed to the different FEL photon energy used in the two experiments or to differences in the sample properties. A systematic X-TG study on the same sample as a function of the FEL wavelength is needed to draw a consistent conclusion. We also discuss how the advances in the performance of the FELs, in terms of generation of fully coherent photon pulses and multi-color FEL emission, may push the development of original experimental strategies to study matter at the femtosecond-nanometer time-length scales, with the unique option of element and chemical state specificity. This would allow the development of advanced experimental tools based on wave-mixing processes, which may have a tremendous impact in the study of a large array of phenomena, ranging from nano-dynamics in complex materials to charge and energy transfer processes.

  16. Temporal laser pulse manipulation using multiple optical ring-cavities

    NASA Technical Reports Server (NTRS)

    Nguyen, Quang-Viet (Inventor); Kojima, Jun (Inventor)

    2010-01-01

    An optical pulse stretcher and a mathematical algorithm for the detailed calculation of its design and performance is disclosed. The optical pulse stretcher has a plurality of optical cavities, having multiple optical reflectors such that an optical path length in each of the optical cavities is different. The optical pulse stretcher also has a plurality of beam splitters, each of which intercepts a portion of an input optical beam and diverts the portion into one of the plurality of optical cavities. The input optical beam is stretched and a power of an output beam is reduced after passing through the optical pulse stretcher and the placement of the plurality of optical cavities and beam splitters is optimized through a model that takes into account optical beam divergence and alignment in the pluralities of the optical cavities. The optical pulse stretcher system can also function as a high-repetition-rate (MHz) laser pulse generator, making it suitable for use as a stroboscopic light source for high speed ballistic projectile imaging studies, or it can be used for high speed flow diagnostics using a laser light sheet with digital particle imaging velocimetry. The optical pulse stretcher system can also be implemented using fiber optic components to realize a rugged and compact optical system that is alignment free and easy to use.

  17. Single cell induced optical confinement in biological lasers

    NASA Astrophysics Data System (ADS)

    Karl, M.; Dietrich, C. P.; Schubert, M.; Samuel, I. D. W.; Turnbull, G. A.; Gather, M. C.

    2017-03-01

    Biological single cell lasers have shown great potential for fundamental research and next generation sensing applications. In this study, the potential of fluorescent biological cells as refractive index landscapes and active optical elements is investigated using a combined Fourier- and hyperspectral imaging technique. We show that the refractive index contrast between cell and surrounding leads to 3D confinement of photons inside living cells. The Fourier- and real-space emission characteristics of these biological lasers are closely related and can be predicted from one another. Investigations of the lasing threshold for different energy and momentum position in Fourier-space give insight into the fundamental creation of longitudinal and transverse lasing modes within the cell. These findings corroborate the potential of living biological materials for precision engineering of photonic structures and may pave the way towards low threshold polariton lasing from single cells.

  18. Multimode laser emission from dye doped polymer optical fiber.

    PubMed

    Sheeba, Mavila; Thomas, Kannampuzha J; Rajesh, Mandamparambil; Nampoori, Vadakkedathu P N; Vallabhan, Chakkalakkal P G; Radhakrishnan, Padmanabhan

    2007-11-20

    Multimode laser emission is observed in a polymer optical fiber doped with a mixture of Rhodamine 6G (Rh 6G) and Rhodamine B (Rh B) dyes. Tuning of laser emission is achieved by using the mixture of dyes due to the energy transfer occurring from donor molecule (Rh 6G) to acceptor molecule (Rh B). The dye doped poly(methyl methacrylate)-based polymer optical fiber is pumped axially at one end of the fiber using a 532 nm pulsed laser beam from a Nd:YAG laser and the fluorescence emission is collected from the other end. At low pump energy levels, fluorescence emission is observed. When the energy is increased beyond a threshold value, laser emission occurs with a multimode structure. The optical feedback for the gain medium is provided by the cylindrical surface of the optical fiber, which acts as a cavity. This fact is confirmed by the mode spacing dependence on the diameter of the fiber.

  19. Optical multiaccess free-space laser communication system

    NASA Astrophysics Data System (ADS)

    Jiang, Lun; Zhang, Li-Zhong; Wang, Chao; An, Yan; Hu, Yuan

    2016-08-01

    With urgent demand for an integrated information network and development of free-space laser communication technology, research on high-rate laser communication networking technology is vital. This study analyzed the technical difficulties related to space laser communication networking and proposed a laser communication networking solution. A wide-angle beam expander and dual-rotating prism group were incorporated into a multiaccess optical laser communication antenna. The wide-angle beam expander collects signal light from different directions; the dual-rotating prism group tracks different targets simultaneously. This paper presents an overall scheme allowing multiaccess free-space laser communications based on the optical antenna described and the associated relay optics and transceiver subsystems.

  20. Active optical sensor technology

    NASA Technical Reports Server (NTRS)

    Melfi, Harvey

    1990-01-01

    An account is given of the development status, performance capabilities, and prospective applications of lidar systems in earth remote sensing, as envisioned by researchers at NASA-Marshall, NASA-Goddard, NASA-Langley, and NASA-Wallops Island. Lidar systems can conduct measurements in research efforts concerned with wind fields, altimetry, ozone depletion, water vapor mixing ratios, temperature and pressure, phytoplankton chlorophyll fluorescence, forest folliage, and ice sheets. It is in all cases that lidar lasers be lightweight, compact, and efficient; most lasers need to be tunable. Detectors used range from photomultipliers to photodiodes.

  1. Analysis of adaptive laser scanning optical system with focus-tunable components

    NASA Astrophysics Data System (ADS)

    Pokorný, P.; Mikš, A.; Novák, J.; Novák, P.

    2015-05-01

    This work presents a primary analysis of an adaptive laser scanner based on two-mirror beam-steering device and focustunable components (lenses with tunable focal length). It is proposed an optical scheme of an adaptive laser scanner, which can focus the laser beam in a continuous way to a required spatial position using the lens with tunable focal length. This work focuses on a detailed analysis of the active optical or opto-mechanical components (e.g. focus-tunable lenses) mounted in the optical systems of laser scanners. The algebraic formulas are derived for ray tracing through different configurations of the scanning optical system and one can calculate angles of scanner mirrors and required focal length of the tunable-focus component provided that the position of the focused beam in 3D space is given with a required tolerance. Computer simulations of the proposed system are performed using MATLAB.

  2. Remote chemical sensing by laser optical pumping

    SciTech Connect

    Stevens, C.G.; Magnotta, F.

    1996-08-01

    We are exploring a new approach to remote chemical identification that promises higher precision than can be achieved by conventional DIAL approaches. This technique also addresses and potentially solves the problem of detecting a target gas in the presence of an interfering gas or gases. This new approach utilizes an eye-safe infrared optical pumping pulse to deplete the population of a specific rotational level(s) and then sends probe pulses at the same or different wavelengths to interrogate the bleaching of the absorption. We have experimentally measured optical saturation fluence level at atmospheric pressure for HCl, and find this level to be {approximately}1 mJ/cm{sup 2}, significantly below eye-safe limits in agreement with calculations. Calculations have been performed on other molecules of interest with similar results. In the laboratory, using time-delay-replicated pulses at a single frequency we have made absorption measurements with precision levels routinely approaching 0.1% after averaging 200 laser pulses. These results as well as those of two other pulse experiments will be presented. 5 refs., 9 figs., 1 tab.

  3. Large aperture adaptive optics for intense lasers

    NASA Astrophysics Data System (ADS)

    Deneuville, François; Ropert, Laurent; Sauvageot, Paul; Theis, Sébastien

    2015-05-01

    ISP SYSTEM has developed a range of large aperture electro-mechanical deformable mirrors (DM) suitable for ultra short pulsed intense lasers. The design of the MD-AME deformable mirror is based on force application on numerous locations thanks to electromechanical actuators driven by stepper motors. DM design and assembly method have been adapted to large aperture beams and the performances were evaluated on a first application for a beam with a diameter of 250mm at 45° angle of incidence. A Strehl ratio above 0.9 was reached for this application. Simulations were correlated with measurements on optical bench and the design has been validated by calculation for very large aperture (up to Ø550mm). Optical aberrations up to Zernike order 5 can be corrected with a very low residual error as for actual MD-AME mirror. Amplitude can reach up to several hundreds of μm for low order corrections. Hysteresis is lower than 0.1% and linearity better than 99%. Contrary to piezo-electric actuators, the μ-AME actuators avoid print-through effects and they permit to keep the mirror shape stable even unpowered, providing a high resistance to electro-magnetic pulses. The MD-AME mirrors can be adapted to circular, square or elliptical beams and they are compatible with all dielectric or metallic coatings.

  4. Enhanced Performance of Large 3(omega) Optics Using UV and IR Lasers

    SciTech Connect

    Prasad, R R; Bruere, J; Peterson, J; Halpin, J; Borden, M; Hackel, R P

    2003-11-01

    We have developed techniques using small-beam raster scanning to laser-condition fused silica optics to increase their damage threshold. Further, we showed that CO{sub 2} lasers could be used to mitigate and stabilize damage sites while still on the order of a few tens of microns in size, thereby greatly increasing the lifetime of an optic. We recently activated the Phoenix pre-production facility to condition and mitigate optics as large as 43 cm x 43 cm. Several full-scale optics have been processed in Phoenix. The optics were first photographed using a damage mapping system to identify scratches, digs, or other potential sites for initiation of laser damage. We then condition the optic, raster scanning with the excimer laser. The first scan is performed at a low fluence. A damage map is then acquired and any new damage sites or any sites that have grown in size are mitigated using the CO{sub 2} laser. The process is repeated at successively higher fluences until a factor of 1.7 above the nominal operating fluence is reached. After conditioning, optics were tested in a large beam 3{omega} laser and showed no damage at fluences of 8 J/cm{sup 2} average.

  5. Integrated semiconductor twin-microdisk laser under mutually optical injection

    SciTech Connect

    Zou, Ling-Xiu; Liu, Bo-Wen; Lv, Xiao-Meng; Yang, Yue-De; Xiao, Jin-Long; Huang, Yong-Zhen

    2015-05-11

    We experimentally study the characteristics of an integrated semiconductor twin-microdisk laser under mutually optical injection through a connected optical waveguide. Based on the lasing spectra, four-wave mixing, injection locking, and period-two oscillation states are observed due to the mutually optical injection by adjusting the injected currents applied to the two microdisks. The enhanced 3 dB bandwidth is realized for the microdisk laser at the injection locking state, and photonic microwave is obtained from the electrode of the microdisk laser under the period-two oscillation state. The plentifully dynamical states similar as semiconductor lasers subject to external optical injection are realized due to strong optical interaction between the two microdisks.

  6. Advances in laser and tissue interactions: laser microbeams and optical trapping (Invited Paper)

    NASA Astrophysics Data System (ADS)

    Serafetinides, Alexander A.; Makropoulou, Mersini; Papadopoulos, Dimitris; Papagiakoumou, Eirini; Pietreanu, D.

    2005-04-01

    The increasing use of lasers in biomedical research and clinical praxis leads to the development and application of new, non-invasive, therapeutic, surgical and diagnostic techniques. In laser surgery, the theory of ablation dictates that pulsed mid-infrared laser beams exhibit strong absorption by soft and hard tissues, restricting residual thermal damage to a minimum zone. Therefore, the development of high quality 3 μm lasers is considered to be an alternative for precise laser ablation of tissue. Among them are the high quality oscillator-two stages amplifier lasers developed, which will be described in this article. The beam quality delivered by these lasers to the biological tissue is of great importance in cutting and ablating operations. As the precision of the ablation is increased, the cutting laser interventions could well move to the microsurgery field. Recently, the combination of a laser scalpel with an optical trapping device, under microscopy control, is becoming increasingly important. Optical manipulation of microscopic particles by focused laser beams, is now widely used as a powerful tool for 'non-contact' micromanipulation of cells and organelles. Several laser sources are employed for trapping and varying laser powers are used in a broad range of applications of optical tweezers. For most of the lasers used, the focal spot of the trapping beam is of the order of a micron. As the trapped objects can vary in size from hundreds of nanometres to hundreds of microns, the technique has recently invaded in to the nanocosomos of genes and molecules. However, the use of optical trapping for quantitative research into biophysical processes requires accurate calculation of the optical forces and torques acting within the trap. The research and development efforts towards a mid-IR microbeam laser system, the design and realization efforts towards a visible laser trapping system and the first results obtained using a relatively new calibration method to

  7. Optical laser systems at the Linac Coherent Light Source

    DOE PAGES

    Minitti, Michael P.; Robinson, Joseph S.; Coffee, Ryan N.; ...

    2015-04-22

    Ultrafast optical lasers play an essential role in exploiting the unique capabilities of recently commissioned X-ray free-electron laser facilities such as the Linac Coherent Light Source (LCLS). Pump–probe experimental techniques reveal ultrafast dynamics in atomic and molecular processes and reveal new insights in chemistry, biology, material science and high-energy-density physics. This manuscript describes the laser systems and experimental methods that enable cutting-edge optical laser/X-ray pump–probe experiments to be performed at LCLS.

  8. Optically pumped semiconductor lasers for atomic and molecular physics

    NASA Astrophysics Data System (ADS)

    Burd, S.; Leibfried, D.; Wilson, A. C.; Wineland, D. J.

    2015-03-01

    Experiments in atomic, molecular and optical (AMO) physics rely on lasers at many different wavelengths and with varying requirements on spectral linewidth, power and intensity stability. Optically pumped semiconductor lasers (OPSLs), when combined with nonlinear frequency conversion, can potentially replace many of the laser systems currently in use. We are developing a source for laser cooling and spectroscopy of Mg+ ions at 280 nm, based on a frequency quadrupled OPSL with the gain chip fabricated at the ORC at Tampere Univ. of Technology, Finland. This OPSL system could serve as a prototype for many other sources used in atomic and molecular physics.

  9. Unidirectionality of an optically pumped far infrared ring laser

    NASA Astrophysics Data System (ADS)

    Matsushima, Kyoji; Higashida, Noriyoshi; Sokabe, Noburu; Ariyasu, Tomio

    1995-02-01

    An experimental and theoretical investigation has been made on the unidirectional operation of an optically pumped far infrared ring laser. A ring laser operating on the 119 μm line of CH 3OH experiences reversal of output direction in either case of (a) the pump frequency being tuned across the line center of the infrared pump transition or (b) the fir cavity being tuned across the far infrared line center. A model based on two-mode laser theory predicts the output directionality of the optically pumped fir ring laser.

  10. Optical laser systems at the Linac Coherent Light Source

    PubMed Central

    Minitti, Michael P.; Robinson, Joseph S.; Coffee, Ryan N.; Edstrom, Steve; Gilevich, Sasha; Glownia, James M.; Granados, Eduardo; Hering, Philippe; Hoffmann, Matthias C.; Miahnahri, Alan; Milathianaki, Despina; Polzin, Wayne; Ratner, Daniel; Tavella, Franz; Vetter, Sharon; Welch, Marc; White, William E.; Fry, Alan R.

    2015-01-01

    Ultrafast optical lasers play an essential role in exploiting the unique capabilities of recently commissioned X-ray free-electron laser facilities such as the Linac Coherent Light Source (LCLS). Pump–probe experimental techniques reveal ultrafast dynamics in atomic and molecular processes and reveal new insights in chemistry, biology, material science and high-energy-density physics. This manuscript describes the laser systems and experimental methods that enable cutting-edge optical laser/X-ray pump–probe experiments to be performed at LCLS. PMID:25931064

  11. Optical laser systems at the Linac Coherent Light Source.

    PubMed

    Minitti, Michael P; Robinson, Joseph S; Coffee, Ryan N; Edstrom, Steve; Gilevich, Sasha; Glownia, James M; Granados, Eduardo; Hering, Philippe; Hoffmann, Matthias C; Miahnahri, Alan; Milathianaki, Despina; Polzin, Wayne; Ratner, Daniel; Tavella, Franz; Vetter, Sharon; Welch, Marc; White, William E; Fry, Alan R

    2015-05-01

    Ultrafast optical lasers play an essential role in exploiting the unique capabilities of recently commissioned X-ray free-electron laser facilities such as the Linac Coherent Light Source (LCLS). Pump-probe experimental techniques reveal ultrafast dynamics in atomic and molecular processes and reveal new insights in chemistry, biology, material science and high-energy-density physics. This manuscript describes the laser systems and experimental methods that enable cutting-edge optical laser/X-ray pump-probe experiments to be performed at LCLS.

  12. Widely tunable lasers enabling efficient and intelligent optical networks

    NASA Astrophysics Data System (ADS)

    Yu, Rang-Chen

    2002-08-01

    Widely tunable laser has been recognized as one of the key enabling technologies for more efficient and intelligent optical networks. We present recent advanced development of a monolithic full band tunable laser device based on sampled grating distributed Bragg reflector (SG-DBR) technology at Agility Communications. We will discuss key performance parameters, as well as long term reliability of a widely tunable laser with high power (> 20mW), wide tuning range (the whole C-band, or L-band), monolithically integrated electro-absorption (EA) modulator and semiconductor optical amplifier (SOA). Optical network applications will also be discussed.

  13. Optics for multimode lasers with elongated depth of field

    NASA Astrophysics Data System (ADS)

    Laskin, Alexander; Laskin, Vadim; Ostrun, Aleksei

    2017-02-01

    Modern multimode high-power lasers are widely used in industrial applications and control of their radiation, especially by focusing, is of great importance. Because of relatively low optical quality, characterized by high values of specifications Beam Parameter Product (BPP) or M², the depth of field by focusing of multimode laser radiation is narrow. At the same time laser technologies like deep penetration welding, cutting of thick metal sheets get benefits from elongated depth of field in area of focal plane, therefore increasing of zone along optical axis with minimized spot size is important technical task. As a solution it is suggested to apply refractive optical systems splitting an initial laser beam into several beamlets, which are focused in different foci separated along optical axis with providing reliable control of energy portions in each separate focus, independently of beam size or mode structure. With the multi-focus optics, the length of zone of material processing along optical axis is defined rather by distances between separate foci, which are determined by optical design of the optics and can be chosen according to requirements of a particular laser technology. Due to stability of the distances between foci there is provided stability of a technology process. This paper describes some design features of refractive multi-focus optics, examples of real implementations and experimental results will be presented as well.

  14. IR-laser assisted additive freeform optics manufacturing.

    PubMed

    Hong, Zhihan; Liang, Rongguang

    2017-08-02

    Computer-controlled additive manufacturing (AM) processes, also known as three-dimensional (3D) printing, create 3D objects by the successive adding of a material or materials. While there have been tremendous developments in AM, the 3D printing of optics is lagging due to the limits in materials and tight requirements for optical applicaitons. We propose a new precision additive freeform optics manufacturing (AFOM) method using an pulsed infrared (IR) laser. Compared to ultraviolet (UV) curable materials, thermally curable optical silicones have a number of advantages, such as strong UV stability, non-yellowing, and high transmission, making it particularly suitable for optical applications. Pulsed IR laser radiation offers a distinct advantage in processing optical silicones, as the high peak intensity achieved in the focal region allows for curing the material quickly, while the brief duration of the laser-material interaction creates a negligible heat-affected zone.

  15. Active materials for integrated optic applications

    NASA Astrophysics Data System (ADS)

    Hayden, Joseph S.; Funk, David S.; Veasey, David L.; Peters, Philip M.; Sanford, Norman A.

    1999-11-01

    The ability to engineer glass properties through the selection and adjustment of chemical composition continues to make glass a leading material in both active and passive applications. The development of optimal glass compositions for integrated optical applications requires a number of considerations that are often at variance with one another. Of critical importance is that the glass offers compatibility with standard ion exchange technologies, allowing fabrication of guided wave structures. In addition, for application as an active material, the resultant structures must be characterized by absence of inclusions and low absorption at the lasing wavelength, putting demands on both the selection and identity of the raw materials used to prepare the glass. We report on the development of an optimized glass composition for integrated optic applications that combines good laser properties with good chemical durability allowing for a wide range of chemical processing steps to be employed without substrate deterioration. In addition, care was taken during the development of this glass to insure that the selected composition was consistent with manufacturing technology for producing high optical quality glass. We present the properties of the resultant glasses, including results of detailed chemical and laser properties, for use in the design and modeling of active waveguides prepared with these glasses.

  16. Laser Safety Method For Duplex Open Loop Parallel Optical Link

    DOEpatents

    Baumgartner, Steven John; Hedin, Daniel Scott; Paschal, Matthew James

    2003-12-02

    A method and apparatus are provided to ensure that laser optical power does not exceed a "safe" level in an open loop parallel optical link in the event that a fiber optic ribbon cable is broken or otherwise severed. A duplex parallel optical link includes a transmitter and receiver pair and a fiber optic ribbon that includes a designated number of channels that cannot be split. The duplex transceiver includes a corresponding transmitter and receiver that are physically attached to each other and cannot be detached therefrom, so as to ensure safe, laser optical power in the event that the fiber optic ribbon cable is broken or severed. Safe optical power is ensured by redundant current and voltage safety checks.

  17. Pulse laser assist optical tweezers (PLAT) with long-duration pulse laser

    NASA Astrophysics Data System (ADS)

    Maeda, Saki; Sugiura, Tadao; Minato, Kotaro

    2011-07-01

    Optical tweezers is a technique to trap and to manipulate micron sized objects under a microscope by radiation pressure force exerted by a laser beam. Optical tweezers has been utilized for single-molecular measurements of force exerted by molecular interactions and for cell palpation. To extend applications of optical tweezers we have developed a novel optical tweezers system combined with a pulse laser. We utilize a pulse laser (Q-switched Nd: YAG laser, wavelength of 1064 nm) to assist manipulations by conventional optical tweezers with a continuous wave (CW) laser. The pulse laser beam is introduced into the same optics for conventional optical tweezers. In principle, instantaneous radiation force is proportional to instantaneous power of laser beam. As a result, pulse laser beam generates strong instantaneous force on an object to be manipulated. If the radiation force becomes strong enough to get over an obstacle structure and/or to be released from adhesion, the object will be free from these difficulties. We investigate the effect of pulse laser assistance with changing pulse duration of the laser. We report optimum pulse duration of 100 ns to 200 ns deduced from motion analysis of a particle in a beam spot. Our goal is to realize in-vivo manipulation and operation of a cell. For this purpose we need to reduce light energy of pulse laser beam and to avoid laser induced breakdown caused by strong light field. So we have developed a pulse laser with 160-ns pulse duration and have confirmed that availability on manipulation of living cells.

  18. Reliability of high power laser diodes with external optical feedback

    NASA Astrophysics Data System (ADS)

    Bonsendorf, Dennis; Schneider, Stephan; Meinschien, Jens; Tomm, Jens W.

    2016-03-01

    Direct diode laser systems gain importance in the fields of material processing and solid-state laser pumping. With increased output power, also the influence of strong optical feedback has to be considered. Uncontrolled optical feedback is known for its spectral and power fluctuation effects, as well as potential emitter damage. We found that even intended feedback by use of volume Bragg gratings (VBG) for spectral stabilization may result in emitter lifetime reduction. To provide stable and reliable laser systems design, guidelines and maximum feedback ratings have to be found. We present a model to estimate the optical feedback power coupled back into the laser diode waveguide. It includes several origins of optical feedback and wide range of optical elements. The failure thresholds of InGaAs and AlGaAs bars have been determined not only at standard operation mode but at various working points. The influence of several feedback levels to laser diode lifetime is investigated up to 4000h. The analysis of the semiconductor itself leads to a better understanding of the degradation process by defect spread. Facet microscopy, LBIC- and electroluminescence measurements deliver detailed information about semiconductor defects before and after aging tests. Laser diode protection systems can monitor optical feedback. With this improved understanding, the emergency shutdown threshold can be set low enough to ensure laser diode reliability but also high enough to provide better machine usability avoiding false alarms.

  19. Active Faraday optical frequency standard.

    PubMed

    Zhuang, Wei; Chen, Jingbiao

    2014-11-01

    We propose the mechanism of an active Faraday optical clock, and experimentally demonstrate an active Faraday optical frequency standard based on narrow bandwidth Faraday atomic filter by the method of velocity-selective optical pumping of cesium vapor. The center frequency of the active Faraday optical frequency standard is determined by the cesium 6 (2)S(1/2) F=4 to 6 (2)P(3/2) F'=4 and 5 crossover transition line. The optical heterodyne beat between two similar independent setups shows that the frequency linewidth reaches 281(23) Hz, which is 1.9×10(4) times smaller than the natural linewidth of the cesium 852-nm transition line. The maximum emitted light power reaches 75 μW. The active Faraday optical frequency standard reported here has advantages of narrow linewidth and reduced cavity pulling, which can readily be extended to other atomic transition lines of alkali and alkaline-earth metal atoms trapped in optical lattices at magic wavelengths, making it useful for new generation of optical atomic clocks.

  20. EFFECTS OF LASER RADIATION ON MATTER. LASER PLASMA: Feasibility of investigation of optical breakdown statistics using multifrequency lasers

    NASA Astrophysics Data System (ADS)

    Ulanov, S. F.

    1990-06-01

    A method proposed for investigating the statistics of bulk optical breakdown relies on multifrequency lasers, which eliminates the influence of the laser radiation intensity statistics. The method is based on preliminary recording of the peak intensity statistics of multifrequency laser radiation pulses at the caustic using the optical breakdown threshold of K8 glass. The probability density distribution function was obtained at the focus for the peak intensities of the radiation pulses of a multifrequency laser. This method may be used to study the self-interaction under conditions of bulk optical breakdown of transparent dielectrics.

  1. Studies of beam expansion and distributed Bragg reflector lasers for fiber optics and optical signal processing

    NASA Astrophysics Data System (ADS)

    Garmire, E. M.

    1981-03-01

    Separate studies were performed on beam expansion and on distributed Bragg Reflector (DBR) lasers preliminary to monolithic integration on GaAs substrates. These components are proposed for use in optical signal processing, for fiber optic sources and for high brightness lasers.

  2. 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.

  3. Optics and photonics research in the Lasers, Optics and Remote Sensing Department at Sandia National Laboratories

    SciTech Connect

    Simmons-Potter, K.; Meister, D.C.

    1997-04-01

    Photonic system and device technologies have claimed a significant share of the current high-tech market. In particular, laser systems and optical devices impact a broad range of technological areas including telecommunications, optical computing, optical data storage, integrated photonics, remote environmental sensing and biomedical applications. Below we present an overview of photonics research being conducted within the Lasers, Optics and Remote Sensing department of the Physical and Chemical Sciences Center at Sandia National Laboratories. Recent results in the fields of photosensitive materials and devices, binary optics device applications, wavelength generation using optical parametric oscillators, and remote sensing are highlighted. 11 refs., 6 figs.

  4. Laser-Based Acousto-Optic Uplink Communications Technique

    DTIC Science & Technology

    2003-08-18

    An apparatus for enabling acousto - optic communication comprising an in-water platform comprising means for emitting an acoustic signal to an acousto ...portion of the first interrogation beam and a second laser beam formed from the reflection of the first interrogation beam off of the acousto - optic interaction... optic interaction zone, an in-air platform comprising the ability for transmitting a first optical interrogation beam, the ability for receiving a

  5. Precision targeting with a tracking adaptive optics scanning laser ophthalmoscope

    NASA Astrophysics Data System (ADS)

    Hammer, Daniel X.; Ferguson, R. Daniel; Bigelow, Chad E.; Iftimia, Nicusor V.; Ustun, Teoman E.; Noojin, Gary D.; Stolarski, David J.; Hodnett, Harvey M.; Imholte, Michelle L.; Kumru, Semih S.; McCall, Michelle N.; Toth, Cynthia A.; Rockwell, Benjamin A.

    2006-02-01

    Precise targeting of retinal structures including retinal pigment epithelial cells, feeder vessels, ganglion cells, photoreceptors, and other cells important for light transduction may enable earlier disease intervention with laser therapies and advanced methods for vision studies. A novel imaging system based upon scanning laser ophthalmoscopy (SLO) with adaptive optics (AO) and active image stabilization was designed, developed, and tested in humans and animals. An additional port allows delivery of aberration-corrected therapeutic/stimulus laser sources. The system design includes simultaneous presentation of non-AO, wide-field (~40 deg) and AO, high-magnification (1-2 deg) retinal scans easily positioned anywhere on the retina in a drag-and-drop manner. The AO optical design achieves an error of <0.45 waves (at 800 nm) over +/-6 deg on the retina. A MEMS-based deformable mirror (Boston Micromachines Inc.) is used for wave-front correction. The third generation retinal tracking system achieves a bandwidth of greater than 1 kHz allowing acquisition of stabilized AO images with an accuracy of ~10 μm. Normal adult human volunteers and animals with previously-placed lesions (cynomolgus monkeys) were tested to optimize the tracking instrumentation and to characterize AO imaging performance. Ultrafast laser pulses were delivered to monkeys to characterize the ability to precisely place lesions and stimulus beams. Other advanced features such as real-time image averaging, automatic highresolution mosaic generation, and automatic blink detection and tracking re-lock were also tested. The system has the potential to become an important tool to clinicians and researchers for early detection and treatment of retinal diseases.

  6. Binary Arithmetic Using Optical Symbolic Substitution and Cascadable Surface-Emitting Laser Logic Devices,

    DTIC Science & Technology

    LOGIC DEVICES, *OPTICAL CIRCUITS, *OPTICAL SWITCHING, HETEROJUNCTIONS, PHOTOTRANSISTORS, ELECTROOPTICS, LASER CAVITIES, OPTICAL PROCESSING, PARALLEL PROCESSING, BISTABLE DEVICES, GATES(CIRCUITS), VOLTAGE, BINARY ARITHMETIC .

  7. 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.

  8. CONTROLLING THE CHARACTERISTICS OF LASER LIGHT: Effect of optical aberrations on the output quality of a two-element laser

    NASA Astrophysics Data System (ADS)

    Malashin, P. O.; Silichev, O. O.

    1993-04-01

    The effect of slight aberrations of an intracavity lens on the mode structure and the quality of the output from a two-element multimode laser is examined theoretically. The coefficients of the mode distortion due to optical aberrations of the intracavity elements are derived by perturbation theory. A general condition for the dynamic stability of the cavity of a two-element laser with respect to small fluctuations of the lens power of the active-element thermal lens is proposed. Recommendations are offered for optimizing the optical layout of the cavity of a two-element solid state laser. These recommendations are aimed at reducing the effect of aberrations on the quality of the transverse structure of the output. The procedure for designing an effective layout for a cavity of a two-element, solid-state industrial laser is illustrated.

  9. Method and apparatus for efficient operation of optically pumped laser

    NASA Technical Reports Server (NTRS)

    Sipes, Jr., Donald L. (Inventor)

    1987-01-01

    An optically pumped single mode laser, e.g., Nd:YAG crystal (20) with planoconcave mirrors is increased in efficiency by an order of magnitude to about 8% by optics (25, 27) for focusing the high power multimode output of laser diode arrays (21, 22) into the mode volume (20') of the laser medium (20). A plurality of these optically pumped single mode lasers (1-4) may be cascaded in a ring with dichroic mirrors (M.sub.1 -M.sub.4) at the corners for coupling in the laser diode arrays, each having its own means for spatially tailoring its beam to concentrate pump distribution inside the lasing mode volume of the medium. An InGaAlAs pump diode (30) with its wavelength the same as the lasing medium makes the ring unidirectional.

  10. Field-Testing of an Active Laser Tracking System

    NASA Astrophysics Data System (ADS)

    Markov, V.; Khiznyak, A.; Woll, D.; Liu, S.

    Comprehensive space surveillance demands a more accurate technique in tracking multi-dimensional state vector (3D coordinate, velocity, vibration, etc.) of the space objects. RF radiometric techniques typically can not provide the needed accuracy, while passive optical (and laser) tracking systems can provide distance to the object and its angular position, but not a direct reading of velocity, the parameter of primary importance for space object tracking and characterization. Addressing this problem with active optical tracking techniques is challenging because of the great distances involved, the high velocity of the satellites, and the optical aberrations induced by the atmosphere. We have proposed a phase conjugation based laser tracking concept, and accomplished the first version of design and engineering of a prototype for an Active Laser Tracking System (ALTS). In its current state the ALTS is capable to demonstrate the very basics operational principles of the proposed active tracking technique. We then performed a number of experiments to prove operational capabilities of this prototype both at MetroLaser's lab environment and at Edwards AFB Test Range. In its current architecture the ALTS is comprised of two laser cavities, Master and Slave that are coupled through a Phase Conjugate Mirror (PCM) formed in a non-linear medium (NLM) set at Master laser cavity. By pumping NLM and forming PCM, Master laser establishes the cavities coupling mode and injects the photons in the slave cavity. It is essential that the specific features of the PCM not only serve to couple ALTS cavities, but also serves to compensate optical aberrations of the ALTS (gain media and optical elements of the laser resonator). Due to its ability to compensate optical aberrations, phase conjugate resonators are capable of sustaining oscillation with a remote target as an output coupler. The entire system comprises of several modules, including a laser, emitting/receiving telescope, gimbal

  11. Pulse laser assisted optical tweezers for biomedical applications.

    PubMed

    Sugiura, Tadao; Maeda, Saki; Honda, Ayae

    2012-01-01

    Optical tweezers which enables to trap micron to nanometer sized objects by radiation pressure force is utilized for manipulation of particles under a microscope and for measurement of forces between biomolecules. Weak force of optical tweezers causes some limitations such as particle adhesion or steric barrier like lipid membrane in a cell prevent further movement of objects. For biomedical applications we need to overcome these difficulties. We have developed a technique to exert strong instantaneous force by use of a pulse laser beam and to assist conventional optical tweezers. A pulse laser beam has huge instantaneous laser power of more than 1000 times as strong as a conventional continuous-wave laser beam so that the instantaneous force is strong enough to break chemical bonding and molecular force between objects and obstacles. We derive suitable pulse duration for pulse assist of optical tweezers and demonstrate particle manipulation in difficult situations through an experiment of particle removal from sticky surface of glass substrate.

  12. Laser beacon adaptive optics for power beaming applications

    NASA Astrophysics Data System (ADS)

    Fugate, Robert Q.

    1994-05-01

    This paper discusses the laser beam control system requirements for power beaming applications. Power beaming applications include electric and thermal engine propulsion for orbit transfer, station changing, and recharging batteries. Beam control includes satellite acquisition, high accuracy tracking, higher order atmospheric compensation using adaptive optics, and precision point-ahead. Beam control may also include local laser beam clean-up with a low order adaptive optics system. This paper also presents results of tracking and higher-order correction experiments on astronomical objects. The results were obtained with a laser beacon adaptive optics system at Phillips Laboratory's Starfire Optical Range near Albuquerque, NM. At a wavelength of 0.85 micrometers , we have achieved Strehl ratios of approximately 0.50 using laser beacons and approximately 0.65 using natural stars for exposures longer than one minute on objects of approximately 8th magnitude. The resulting point spread function has a full width half maximum (FWHM) of 0.13 arcsec.

  13. Optically pumped Cs vapor lasers: pump-to-laser beam overlap optimization

    NASA Astrophysics Data System (ADS)

    Auslender, Ilya; Cohen, Tom; Lebiush, Eyal; Barmashenko, Boris D.; Rosenwaks, Salman

    2017-01-01

    We present the results of an experimental study of Ti:Sapphire pumped Cs laser and theoretical modeling of these results, where we focused on the influence of the pump-to-laser beam overlap, a crucial parameter for optimizing the output laser power. The dependence of the output laser power on the incident pump power was found for varying pump beam cross-section widths and for a constant laser beam. Maximum laser power > 370 mW with an optical-to-optical efficiency of 43% and slope efficiency 55% was obtained. Non monotonic dependence of the laser power and threshold power on the pump beam radius (at a given pump power) was observed with a maximum laser power and minimum threshold power achieved at the ratio 0.7 between the optimal pump beam and laser beam radius. A simple optical model of the laser, where Gaussian spatial shapes of the pump and laser intensities in any cross section of the beams were assumed, was compared to the experiments. Good agreement was obtained between the measured and calculated dependence of the laser power on the incident pump power at different pump beam radii and of the laser power, threshold power and optimal temperature on the pump beam radius. The model does not use empirical parameters such as mode overlap efficiency but rather the pump and laser beam spatial shapes as input parameters. This model can be applied to different optically pumped alkali lasers with arbitrary spatial distributions of the pump and laser beam widths.

  14. Label-free optical activation of astrocyte in vivo

    NASA Astrophysics Data System (ADS)

    Choi, Myunghwan; Yoon, Jonghee; Ku, Taeyun; Choi, Kyungsun; Choi, Chulhee

    2011-07-01

    As the most abundant cell type in the central nervous system, astrocyte has been one of main research topics in neuroscience. Although various tools have been developed, at present, there is no tool that allows noninvasive activation of astrocyte in vivo without genetic or pharmacological perturbation. Here we report a noninvasive label-free optical method for physiological astrocyte activation in vivo using a femtosecond pulsed laser. We showed the laser stimulation robustly induced astrocytic calcium activation in vivo and further verified physiological relevance of the calcium increase by demonstrating astrocyte mediated vasodilation in the brain. This novel optical method will facilitate noninvasive physiological study on astrocyte function.

  15. Erbium Doped GaN Lasers by Optical Pumping

    DTIC Science & Technology

    2016-07-13

    P.O. Box 12211 Research Triangle Park, NC 27709-2211 Er doped GaN, gain medium, high energy laser, optical pump REPORT DOCUMENTATION PAGE 11. SPONSOR...Nanophotonics Center, Texas Tech University Lubbock, TX 79409-3102 jingyu.lin@ttu.edu; hx.jiang@ttu.edu I. Summary of Progress High energy and...emerging technologies. The optical gain medium is the heart of a high energy laser (HEL) system. Comparing with the presently dominant gain material

  16. Integrated Electro-optical Laser-Beam Scanners

    NASA Technical Reports Server (NTRS)

    Boord, Warren T.

    1990-01-01

    Scanners using solid-state devices compact, consume little power, and have no moving parts. Integrated electro-optical laser scanner, in conjunction with external lens, points outgoing beam of light in any number of different directions, depending on number of upper electrodes. Offers beam-deflection angles larger than those of acousto-optic scanners. Proposed for such diverse applications as nonimpact laser printing, color imaging, ranging, barcode reading, and robotic vision.

  17. Integrated Electro-optical Laser-Beam Scanners

    NASA Technical Reports Server (NTRS)

    Boord, Warren T.

    1990-01-01

    Scanners using solid-state devices compact, consume little power, and have no moving parts. Integrated electro-optical laser scanner, in conjunction with external lens, points outgoing beam of light in any number of different directions, depending on number of upper electrodes. Offers beam-deflection angles larger than those of acousto-optic scanners. Proposed for such diverse applications as nonimpact laser printing, color imaging, ranging, barcode reading, and robotic vision.

  18. Laser beaming demonstrations at the Starfire Optical Range

    SciTech Connect

    Lipinski, R.J.; Meister, D.C.; Tucker, S.; Leatherman, P.; Fugate, R.Q.; Maes, C.; Lange, W.J.; Cowan, W.

    1995-03-01

    The ability to acquire, track, and accurately direct a laser beam to a satellite is crucial for power-beaming and laser-communications. To assess the state of the art in this area, a team consisting of Air Force Phillips Laboratory, Sandia National Laboratories, and COMSAT Corporation personnel performed some laser beaming demonstrations to various satellites. A ruby laser and a frequency-doubled YAG laser were used with the Phillips Lab Starfire Optical Range (SOR) beam director for this activity. The ruby laser projected 20 J in 6 ms out the telescope with a beam divergence that increased from 1.4 to 4 times the diffraction limit during that time. The doubled YAG projected 0.09 J in 10 ns at 20 Hz. The SOR team demonstrated the ability to move rapidly to a satellite, center it in the telescope, then lock onto it with the tracker, and establish illumination. Several low-earth-orbit satellites with corner-cube retro-reflectors were illuminated at ranges from 1000 to 6000 km with a beam divergence estimated to be about 20 {mu}radians. The return signal from the ruby laser was collected in a 15-cm telescope, detected by a photomultiplier tube, and recorded at 400 kHz. Rapid variations in intensity (as short at 15 {mu}s) were noted, which may be due to speckles caused by phase interference from light reflected from different retro-reflectors on the satellite. The return light from the YAG was collected by a 35-cm telescope and detected by an intensified CCD camera. The satellite brightened by about a factor of 30 in the sunlight when the laser was turned on, and dimmed back to normal when the 50-{mu}radian point-ahead was turned off. The satellite was illuminated at 1 Hz as it entered the earth`s shadow and followed for about 10 seconds in the shadow. In another demonstration, four neighboring GEO satellites were located and centered in succession with a 3.5-m telescope at a rate of about 16 seconds per satellite.

  19. Diffractive-optics-based beam combination of a phase-locked fiber laser array.

    PubMed

    Cheung, Eric C; Ho, James G; Goodno, Gregory D; Rice, Robert R; Rothenberg, Josh; Thielen, Peter; Weber, Mark; Wickham, Michael

    2008-02-15

    A diffractive optical element (DOE) is used as a beam combiner for an actively phase-locked array of fiber lasers. Use of a DOE eliminates the far-field sidelobes and the accompanying loss of beam quality typically observed in tiled coherent laser arrays. Using this technique, we demonstrated coherent combination of five fiber lasers with 91% efficiency and M2=1.04. Combination efficiency and phase locking is robust even with large amplitude and phase fluctuations on the input laser array elements. Calculations and power handling measurements suggest that this approach can scale to both high channel counts and high powers.

  20. Adaptive optics for control of the laser welding process

    NASA Astrophysics Data System (ADS)

    Mrňa, Libor; Šarbort, Martin; Řeřucha, Šimon; Jedlička, Petr

    2013-04-01

    The laser head with fixed focus optics is commonly used for the deep penetration laser welding. In such case the geometry and position of the beam waist are defined by the focusing lens. If the laser beam incident on the focusing lens is not well collimated but divergent and its divergence can be varied by proper adaptive optical elements, then also the geometry and position of the focus will be changeable. In this way it is possible to affect the energy coupling from the laser beam to the keyhole walls and thus to control the geometry and quality of the weld. In this paper we present a theoretical and numerical study of the beam shaping by adaptive optics and its influence on the weld quality. For the CO2 laser welding machine the adaptive optics was realized by a deformable mirror and itsti'ect was tested also experimentally. For the solid-state laser welding machine we designed a laser head with changeable distance between the optical fiber and the collimating lens and we simulated its performance.

  1. Machining of optical microstructures with 157 nm laser radiation

    NASA Astrophysics Data System (ADS)

    Temme, Thorsten; Ostendorf, Andreas; Kulik, Christian J.

    2003-11-01

    The precision machining of glass by laser ablation has been expanded with the short wavelength of the 157 nm of the F2 excimer laser. The high absorption of this wavelength in any optical glass, especially in UV-grade fused silica, offers a new approach to generate high quality surfaces, addressing also micro-optical components. In this paper, the machining of basic diffractive and refractive optical components and the required machining and process technology is presented. Applications that are addressed are cylindrical and rotational symmetrical micro lenses and diffractive optics like phase transmission grating and diffractive optical elements (DOEs). These optical surfaces have been machined into bulk material as well as on fiber end surfaces, to achieve compact (electro) -- optical elements with high functionality and packaging density. The short wavelength of 157 nm used in the investigations require either vacuum or high purity inert gas environments. The influence of different ambient conditions is presented.

  2. Optical communication with semiconductor laser diodes

    NASA Technical Reports Server (NTRS)

    Davidson, F.

    1987-01-01

    A 25 megabit/sec direct detection optical communication system that used Q=4 PPM signalling was constructed and its performance measured under laboratory conditions. The system used a single-mode AlGaAs laser diode transmitter and low noise silicon avalanche photodiode (APD) photodetector. Comparison of measured performance with the theoretical revealed that modeling the APD output as a Gaussian process under conditions of negligible background radiation and low (less than 10 to the -12 power A) APD bulk leakage currents leads to substantial underestimates of optimal APD gain to use and overestimates of system bit error probability. A procedure is given to numerically compute system performance which uses the more accurate Webb's Approximation of the exact Conradi distribution for the APD ouput signal that does not require excessive amounts of computer time (a few minutes of VAX 8600 CPU time per system operating point). Examples are given which illustrate the breakdown of the Gaussian approximation in assessing system performance. This system achieved a bit error probability of 10 to the -6 power at a received signal energy corresponding to an average of 60 absorbed photons/bit and optimal APD gain of 700.

  3. Optical communication with semiconductor laser diodes

    NASA Technical Reports Server (NTRS)

    Davidson, F.

    1988-01-01

    Slot timing recovery in a direct detection optical PPM communication system can be achieved by processing the photodetector waveform with a nonlinear device whose output forms the input to a phase lock group. The choice of a simple transition detector as the nonlinearity is shown to give satisfactory synchronization performance. The rms phase error of the recovered slot clock and the effect of slot timing jitter on the bit error probability were directly measured. The experimental system consisted of an AlGaAs laser diode (lambda = 834 nm) and a silicon avalanche photodiode (APD) photodetector and used Q=4 PPM signaling operated at a source data rate of 25 megabits/second. The mathematical model developed to characterize system performance is shown to be in good agreement with actual performance measurements. The use of the recovered slot clock in the receiver resulted in no degradation in receiver sensitivity compared to a system with perfect slot timing. The system achieved a bit error probability of 10 to the minus 6 power at received signal energies corresponding to an average of less than 60 detected photons per information bit.

  4. Laser guide stars and adaptive optics for astronomy

    SciTech Connect

    Max, C.E.

    1992-07-15

    Five papers are included: feasibility experiment for sodium-alyer laser guide stars at LLNL; system design for a high power sodium beacon laser; sodium guide star adaptive optics system for astronomical imaging in the visible and near-infrared; high frame-rate, large field wavefront sensor; and resolution limits for ground-based astronomical imaging. Figs, tabs, refs.

  5. Refractive beam shapers for optical systems of lasers

    NASA Astrophysics Data System (ADS)

    Laskin, Alexander; Laskin, Vadim; Ostrun, Aleksei

    2015-02-01

    Performance of modern high-power lasers can be strongly improved by control of irradiance distribution in laser optical systems: flat-top or super-Gaussian irradiance profiles are optimum for amplification in MOPA lasers and for reduction of thermal effects in crystals of solid-state ultra-short pulse lasers; variable profiles are also important in irradiating of photocathode of Free Electron lasers (FEL). This task can be easily solved with using beam shaping optics, for example, the field mapping refractive beam shapers like Shaper. The operational principle of these devices presumes transformation of laser beam intensity from Gaussian to flattop one with high flatness of output wavefront, saving of beam consistency, providing collimated output beam of low divergence, high transmittance, extended depth of field, negligible residual wave aberration, and achromatic design provides capability to work with ultra-short pulse lasers having broad spectrum. With using the same Shaper it is possible to realize various beam profiles like flattop, inverse Gauss or super Gauss by simple variation of input beam diameter. This paper will describe some design basics of refractive beam shapers of the field mapping type and optical layouts of their applying in optical systems of high-power lasers. Examples of real implementations and experimental results will be presented as well.

  6. Combination of a 2-D acousto-optic deflector with laser amplifier for efficient scanning of a Q-switched ND:YAG laser

    NASA Astrophysics Data System (ADS)

    Maák, P.; Jakab, L.; Richter, P. I.; Brignon, A.; Huignard, J.-P.

    2000-03-01

    A two-dimensional acousto-optic deflector has been combined with a large angular acceptance, laser diode-pumped Nd:YAG optical amplifier in order to obtain a scanning system with high angular resolution and with high and uniform optical transmission. Experiments have been carried out in order to optimize the set-up for intensity distribution and optical losses. The combination of newly developed nonlinear and active optical elements provides a relatively uniform intensity distribution over the scanned region corresponding to 300×300 discrete points in the back focal plane of a Fourier lens, at laser pulse energy levels of 1-5 mJ.

  7. Scalable high-power optically pumped GaAs laser

    NASA Astrophysics Data System (ADS)

    Le, H. Q.; di Cecca, S.; Mooradian, A.

    1991-05-01

    The use of disk geometry, optically pumped semiconductor gain elements for high-power scalability and good transverse mode quality has been studied. A room-temperature TEM00 transverse mode, external-cavity GaAs disk laser has been demonstrated with 500 W peak-power output and 40-percent slope efficiency, when pumped by a Ti:Al2O3 laser. The conditions for diode laser pumping are shown to be consistent with available power level.

  8. Review of antireflective surface structures on laser optics and windows.

    PubMed

    Busse, Lynda E; Frantz, Jesse A; Shaw, L Brandon; Aggarwal, Ishwar D; Sanghera, Jasbinder S

    2015-11-01

    We present recent advancements in structured, antireflective surfaces on optics, including crystals for high-energy lasers as well as windows for the infrared wavelength region. These structured surfaces have been characterized and show high transmission and laser damage thresholds, making them attractive for these applications. We also present successful tests of windows with antireflective surfaces that were exposed to simulated harsh environments for the application of these laser systems.

  9. A Comparison of Two Prototype Laser-Optical Firing Systems

    SciTech Connect

    Gregg L. Morelli; Michelle R. Bright

    2008-08-11

    The design and characterization of small, ruggedized laser-optical subsystems is required for the continued development of robust laser-optical firing systems. Typically, these subsystems must be capable of generating the needed laser optical energy, delivering that energy via fiber-optical cables while taking up occupying a volume as small as possible. A novel beam splitting and fiber injection scheme has been proposed which utilizes two diffractive optical components. These components were utilized to reduce the volume of a previously designed system. A laser-optical prototype system was assembled and tested which utilized this beam splitting and fiber injection scheme along other modifications to the laser module and the power supply. This prototype was based on earlier designs that utilized environmentally proven opto-mechanical sub-assemblies. The system was tested to characterize the laser performance, the splitter-coupler transmission efficiency, channel-to-channel energy balance and fiber interchangeability. The results obtained for this design will be compared to the performance of a prototype system based on a more traditional beam splitting and fiber injection scheme. The traditional design utilized partially reflecting mirrors for beam splitting and plano-convex lenses for fiber injection. These results will be discussed as will their ultimate impact on future designs and packaging strategies.

  10. Active tracking lasers for precision target stabilization

    NASA Astrophysics Data System (ADS)

    Riker, Jim F.

    2003-09-01

    Lasers have historically been considered in the context of weapons, but recent progress has also permitted us to consider using lasers for more subtle applications such as designation, tracking, and discrimination. In this paper, we will review the state of the art of active tracking, including effects such as laser beam quality, diffraction, atmospheric turbulence, and other aspects of laser interactions with its propagation environment. We will present the theory for using lasers in these lower power applications.

  11. Optical ordance system for use in explosive ordnance disposal activities

    SciTech Connect

    Merson, J.A.; Salas, F.J.; Helsel, F.M.

    1994-01-01

    A portable hand-held solid state rod laser system and an optically-ignited detonator have been developed for use in explosive ordnance disposal (EOD) activities. Laser prototypes from Whittaker Ordnance and Universal Propulsion have been tested and evaluated. The optical detonator contains 2-(5 cyanotetrazolato) pentaamine cobalt III perchlorate (CP) as the DDT column and the explosive Octahydro 1, 3, 5, 7 -- tetranitro -- 1, 3, 5, 7 -- tetrazocine (HMX) as the output charge. The laser is designed to have an output of 150 mJ in a 500 microsecond pulse. This output allows firing through 2000 meters of optical fiber. The detonator can also be ignited with a portable laser diode source through a shorter length of fiber.

  12. Optical ordnance system for use in explosive ordnance disposal activities

    NASA Technical Reports Server (NTRS)

    Merson, J. A.; Salas, F. J.; Helsel, F.M.

    1994-01-01

    A portable hand-held solid state rod laser system and an optically-ignited detonator have been developed for use in explosive ordnance disposal (EOD) activities. Laser prototypes from Whittaker Ordnance and Universal Propulsion have been tested and evaluated. The optical detonator contains 2-(5 cyanotetrazolato) pentaamine cobalt(III) perchlorate (CP) as the DDT column and the explosive Octahydro- 1,3,5,7 - tetrazocine (HMX) as the output charge. The laser is designed to have an output of 150 mJ in a 500 microsecond pulse. This output allows firing through 2000 meters of optical fiber. The detonator can also be ignited with a portable laser diode source through a shorter length of fiber.

  13. Optical ordnance system for use in explosive ordnance disposal activities

    NASA Technical Reports Server (NTRS)

    Merson, J. A.; Salas, F. J.; Helsel, F.M.

    1994-01-01

    A portable hand-held solid state rod laser system and an optically-ignited detonator have been developed for use in explosive ordnance disposal (EOD) activities. Laser prototypes from Whittaker Ordnance and Universal Propulsion have been tested and evaluated. The optical detonator contains 2-(5 cyanotetrazolato) pentaamine cobalt(III) perchlorate (CP) as the DDT column and the explosive Octahydro- 1,3,5,7 - tetrazocine (HMX) as the output charge. The laser is designed to have an output of 150 mJ in a 500 microsecond pulse. This output allows firing through 2000 meters of optical fiber. The detonator can also be ignited with a portable laser diode source through a shorter length of fiber.

  14. Monitoring of the protective glass during laser cladding with active fiber laser

    NASA Astrophysics Data System (ADS)

    Valsecchi, Bruno; Previtali, Barbara

    2012-06-01

    This paper deals with the monitoring of the protective glass in a laser cladding head specifically designed for high power active fiber laser beams. The available high power density that can be focused on the workpiece surface is not only one of the most well known positive features of the fiber laser sources but becomes a very critical thermal load acting on the optical elements of the cladding head, in particular in dirty processes such as the laser cladding. The cladding powder indeed coming from the powder cone is likely to interact with the optical elements of the cladding head. As a result the optical elements become locally opaque and absorb the laser beam, with consequent thermal deformation, coating damage and lens breakage. The protective glass, that divides the focusing and collimation lenses from the dirty work area, has the fundamental role to protect the entire optical chains and represents the element whose life has to be continuously monitored in order to avoid unexpected and unpleasant lens damages. The paper presents the study of a monitoring device aimed at monitoring the life of the protective glass making use of the scattered light from the protective glass. The developed monitoring device is able to recognize both small (i.e. cracks) and big defects (i.e. diffuse opacity) on the surface of the protective glass. In order to test the developed monitoring system a real industrial case is investigated making use of a new prototypal laser head assisted by the monitoring device.

  15. Optical properties of polydimethylsiloxane (PDMS) during nanosecond laser processing

    NASA Astrophysics Data System (ADS)

    Stankova, N. E.; Atanasov, P. A.; Nikov, Ru. G.; Nikov, R. G.; Nedyalkov, N. N.; Stoyanchov, T. R.; Fukata, N.; Kolev, K. N.; Valova, E. I.; Georgieva, J. S.; Armyanov, St. A.

    2016-06-01

    This article presents experimental investigations of effects of the process parameters on the medical grade polydimethylsiloxane (PDMS) elastomer processed by laser source with irradiation at UV (266 and 355 nm), VIS (532 nm) and NIR (1064 nm). Systematic experiments are done to characterize how the laser beam parameters (wavelength, fluence, and number of pulses) affect the optical properties and the chemical composition in the laser treated areas. Remarkable changes of the optical properties and the chemical composition are observed. Despite the low optical absorption of the native PDMS for UV, VIS and NIR wavelengths, successful laser treatment is accomplished due to the incubation process occurring below the polymer surface. With increasing of the fluence and the number of the pulses chemical transformations are revealed in the entire laser treated area and hence decreasing of the optical transmittance is observed. The incubation gets saturation after a certain number of pulses and the laser ablation of the material begins efficiently. At the UV and VIS wavelengths the number of the initial pulses, at which the optical transmittance begins to reduce, decreases from 16 up to 8 with increasing of the laser fluence up to 1.0, 2.5 and 10 J cm-2 for 266, 355 and 532 nm, respectively. In the case of 1064 nm the optical transmittance begins to reduce at 11th pulse incident at a fluence of 13 J cm-2 and the number of the pulses decreases to 8 when the fluence reaches value of 16 J cm-2. The threshold laser fluence needed to induce incubation process after certain number of pulses of 8 is different for every wavelength irradiation as the values increase from 1.0 for 266 nm up to 16 J cm-2 for 1064 nm. The incubation and the ablation processes occur in the PDMS elastomer material during its pulsed laser treatment are a complex function of the wavelength, fluence, number of pulses and the material properties as well.

  16. Characterization of the Los Alamos IPG YLR-6000 fiber laser using multiple optical paths and laser focusing optics

    SciTech Connect

    Milewski, John O; Bernal, John E

    2009-01-01

    Fiber laser technology has been identified as the replacement power source for the existing Los Alamos TA-55 production laser welding system. An IPG YLR-6000 fiber laser was purchased, installed at SM-66 R3, and accepted in February 2008. No characterization of the laser and no welding was performed in the Feb 2008 to May 2009 interval. T. Lienert and J. Bernal (Ref. 1, July 2009) determined the existing 200 mm Rofin collimator and focus heads used with the Rofin diode pumped lasers were inadequate for use with the IPG laser due to clipping of the IPG laser beam. Further efforts in testing of the IPG laser with Optoskand fiber delivery optics and a Rofin 120 mm collimator proved problematic due to optical fiber damage. As a result, IPG design optical fibers were purchased as replacements for subsequent testing. Within the same interval, an IPG fiber-to-fiber (F2F) connector, custom built for LANL, (J. Milewski, S. Gravener, Ref.2) was demonstrated and accepted at IPG Oxford, MA in August 2009. An IPG service person was contracted to come to LANL to assist in the installation, training, troubleshooting and characterization of the multiple beam paths and help perform laser head optics characterization. The statement of work is provided below: In summary the laser system, optical fibers, F2F connector, Precitec head, and a modified Rofin type (w/120mm Optoskand collimator) IWindowIBoot system focus head (Figure 1) were shown to perform well at powers up to 6 kW CW. Power measurements, laser spot size measurements, and other characterization data and lessons learned are contained within this report. In addition, a number of issues were identified that will require future resolution.

  17. Virtual Mie particle model of laser damage to optical elements

    NASA Astrophysics Data System (ADS)

    Hirata, Kazuya; Haraguchi, Koshi

    2011-12-01

    In recent years, devices being developed for application systems have used laser beams that have high average power, high peak power, short pulse width, and short wavelength. Therefore, optical elements using such application systems require a high laser damage threshold. The laser damage threshold is provided by International Organization for Standardization 11254 (ISO11254). One of the measurement methods of the laser damage threshold provided by ISO11254 is an online method to measure the intensity of light scattering due to a laser damage trace. In this paper, we propose a measurement method for the laser damage threshold that realizes high sensitivity and high accuracy by using polarized light and lock-in detection. Since the scattering light with laser damage is modeled on the asperity of the optical element-surface as Mie particles (virtual Mie particles), we consider the intensity change of scattering light as a change in the radius of a virtual Mie particle. To evaluate this model, the laser damage trace on the optical element-surface was observed by an atomic force microscopy (AFM). Based on the observed AFM image, we analyzed the frequency domain by the Fourier transform, and estimated the dominant virtual Mie particle radius in the AFM measurement area. In addition, we measured the laser damage threshold. The light source was the fifth generation of a Nd:YAG laser (λ =213nm). The specifications of the laser were: repetition frequency 10Hz, pulse width 4ns, linear type polarization, laser pulse energy 4mJ, and laser transverse mode TEM00. The laser specifications were a repetition frequency, pulse width, pulse energy and beam diameter of 10Hz, 4ns, 4mJ and 13mm, respectively. The laser damage thresholds of an aluminum coated mirror and a dielectric multi-layer mirror designed at a wavelength of 213nm as measured by this method were 0.684 J/cm2 and 0.998J/cm2, respectively. These laser damage thresholds were 1/4 the laser damage thresholds measured based

  18. Skin optical clearing for improvement of laser tattoo removal

    NASA Astrophysics Data System (ADS)

    Bashkatov, A. N.; Genina, E. A.; Tuchin, V. V.; Altshuler, G. B.

    2009-06-01

    The possibility of improvement of laser tattoo removal due to the optical clearing of human skin is investigated. It is shown experimentally that previously perforation of skin stratum corneum allows increasing tattoo image contrast at topical administration of immersion agent in contrast with non-perforated skin. Computer Monte Carlo simulation shows that at the optical clearing of upper skin layers the tattoo image contrast and the photon fraction absorbed in the tattoo area at the depths of 0.5 or 1.0 mm increase, that allows significant decreasing of the power of laser radiation used at laser thermolysis.

  19. Predicting threshold and location of laser damage on optical surfaces

    DOEpatents

    Siekhaus, W.

    1985-02-04

    Disclosed is an apparatus useful in the prediction of the damage threshold of various optical devices, the location of weak spots on such devices and the location, identification, and elimination of optical surface impurities. The apparatus comprises a focused and pulsed laser, a photo electric detector/imaging means, and a timer. The weak spots emit photoelectrons when subjected to laser intensities that are less than the intensity actually required to produce the damage. The weak spots may be eliminated by sustained exposure to the laser beam.

  20. Temperature Monitoring by Optical Methods in Laser Processing

    NASA Astrophysics Data System (ADS)

    Smurov, I.; Doubenskaia, M.

    Diverse optical diagnostic tools were applied for monitoring high temperature heat and mass transfer in a number of laser-based technologies . A set of pyrometers was developed and applied for surface temperature monitoring in pulsed periodic Nd-YAG laser welding and surface treatment, deep penetration welding by CO2 and Nd:YAG lasers, laser cladding (LC) with lateral and coaxial powder injection, and selective laser melting (SLM). Particle-in-flight parameters in LC were measured by CCD camera-based diagnostic system. Infrared camera was applied for process visualization in laser welding, cladding, and SLM. Process monitoring was carried out at different temporal and spatial scales and in different spectral bands. True temperature was restored in pulsed laser surface treatment and in pulsed periodic (PP) LC.

  1. Laser Induced Damage in Optical Materials: 1979.

    DTIC Science & Technology

    1980-07-01

    an oscillator in laser fusion systems [8, 9]. Tm:YLF, pumped by an XeF laser , and emitting at 453 nm [10], is an efficient storage laser and is being...Chicklis, [4] Wilson, R., Varian Associates (private E.P. and Jenssen, H.P., XeF pumped communication). Tm:YLF an excimer excited storage laser , Technical...caused by pulsed laser -induced thermal stress were not signifi- cantly influenced by transverse heat conduction. However, the fluence levels were above

  2. Optical logic and signal processing using a semiconductor laser diode-based optical bistability device

    NASA Astrophysics Data System (ADS)

    Zhang, Yuancheng; Song, Qian; He, Shaowei

    1995-02-01

    Using an optical fibre-coupled semiconductor laser diode OBD with output feedback pumping operation in 5 modes (differential gain, bistability, zero-bias, inverted differential gain, and inverted bistability) has been realized respectively, and 5 elementary optical logic functions (AND, OR, NOT, NAND, and NOR) and some optical signal processing such as limiting, reshaping, and triggering have been implemented.

  3. Graphene Oxides as Tunable Broadband Nonlinear Optical Materials for Femtosecond Laser Pulses.

    PubMed

    Jiang, Xiao-Fang; Polavarapu, Lakshminarayana; Neo, Shu Ting; Venkatesan, T; Xu, Qing-Hua

    2012-03-15

    Graphene oxide (GO) thin films on glass and plastic substrates were found to display interesting broadband nonlinear optical properties. We have investigated their optical limiting activity for femtosecond laser pulses at 800 and 400 nm, which could be tuned by controlling the extent of reduction. The as-prepared GO films were found to exhibit excellent broadband optical limiting behaviors, which were significantly enhanced upon partial reduction by using laser irradiation or chemical reduction methods. The laser-induced reduction of GO resulted in enhancement of effective two-photon absorption coefficient at 400 nm by up to ∼19 times and enhancement of effective two- and three-photon absorption coefficients at 800 nm by ∼12 and ∼14.5 times, respectively. The optical limiting thresholds of partially reduced GO films are much lower than those of various previously reported materials. Highly reduced GO films prepared by using the chemical method displayed strong saturable absorption behavior.

  4. Green laser light activates the inner ear

    NASA Astrophysics Data System (ADS)

    Wenzel, Gentiana I.; Balster, Sven; Zhang, Kaiyin; Lim, Hubert H.; Reich, Uta; Massow, Ole; Lubatschowski, Holger; Ertmer, Wolfgang; Lenarz, Thomas; Reuter, Guenter

    2009-07-01

    The hearing performance with conventional hearing aids and cochlear implants is dramatically reduced in noisy environments and for sounds more complex than speech (e. g. music), partially due to the lack of localized sensorineural activation across different frequency regions with these devices. Laser light can be focused in a controlled manner and may provide more localized activation of the inner ear, the cochlea. We sought to assess whether visible light with parameters that could induce an optoacoustic effect (532 nm, 10-ns pulses) would activate the cochlea. Auditory brainstem responses (ABRs) were recorded preoperatively in anesthetized guinea pigs to confirm normal hearing. After opening the bulla, a 50-μm core-diameter optical fiber was positioned in the round window niche and directed toward the basilar membrane. Optically induced ABRs (OABRs), similar in shape to those of acoustic stimulation, were elicited with single pulses. The OABR peaks increased with energy level (0.6 to 23 μJ/pulse) and remained consistent even after 30 minutes of continuous stimulation at 13 μJ, indicating minimal or no stimulation-induced damage within the cochlea. Our findings demonstrate that visible light can effectively and reliably activate the cochlea without any apparent damage. Further studies are in progress to investigate the frequency-specific nature and mechanism of green light cochlear activation.

  5. Laser Measurement of Optical Errors of the Eye

    ERIC Educational Resources Information Center

    Colicchia, Giuseppe; Wiesner, Hartmut

    2006-01-01

    One way to motivate students' interest in physics is to teach it in the context of medicine. Optics, for example, can be taught with examples from the eye. For many years simple optics of lenses has been taught using a model of the eye. However, recent advances in using lasers for ophthalmological (ocular) examinations can be used to increase…

  6. Laser Measurement of Optical Errors of the Eye

    ERIC Educational Resources Information Center

    Colicchia, Giuseppe; Wiesner, Hartmut

    2006-01-01

    One way to motivate students' interest in physics is to teach it in the context of medicine. Optics, for example, can be taught with examples from the eye. For many years simple optics of lenses has been taught using a model of the eye. However, recent advances in using lasers for ophthalmological (ocular) examinations can be used to increase…

  7. Acousto-optical imaging using a powerful long pulse laser

    NASA Astrophysics Data System (ADS)

    Rousseau, Guy; Blouin, Alain; Monchalin, Jean-Pierre

    2008-06-01

    Acousto-optical imaging is an emerging biodiagnostic technique which provides an optical spectroscopic signature and a spatial localization of an optically absorbing target embedded in a strongly scattering medium. The transverse resolution of the technique is determined by the lateral extent of ultrasound beam focal zone while the axial resolution is obtained by using short ultrasound pulses. Although very promising for medical diagnostic, the practical application of this technique is presently limited by its poor sensitivity. Moreover, any method to enhance the signal-to-noise ratio must obviously satisfy the in vivo safety limits regarding the acceptable power level of both the ultrasonic pressure wave and the laser beam. In this paper, we propose to improve the sensitivity by using a pulsed single-frequency laser source to raise the optical peak power applied to the scattering medium and to collect more ultrasonically tagged photons. Such a laser source also allows illuminating the tissues mainly during the transit time of the ultrasonic wave to maintain the average optical power below the maximum permissible exposure. In our experiment, a single-frequency Nd:YAG laser emitting 500-μs pulses with a peak power superior to 100 W was used. Photons were tagged in few-cm thick optical phantoms with tone bursts generated by an ultrasonic transducer. Tagged photons were detected with a GaAs photorefractive interferometer characterized by a large optical etendue to process simultaneously a large number of speckle grains. When pumped by high intensity laser pulses, such an interferometer also provides the fast response time essential to obtain an apparatus insensitive to the speckle decorrelation due to mechanical vibrations or tissues movements. The use of a powerful long pulse laser appears promising to enhance the signal level in ultrasound modulated optical imaging. When combined with a photorefractive interferometer of large optical etendue, such a source could

  8. Laser based analysis using a passively Q-switched laser employing analysis electronics and a means for detecting atomic optical emission of the laser media

    DOEpatents

    Woodruff, Steven D.; Mcintyre, Dustin L.

    2016-03-29

    A device for Laser based Analysis using a Passively Q-Switched Laser comprising an optical pumping source optically connected to a laser media. The laser media and a Q-switch are positioned between and optically connected to a high reflectivity mirror (HR) and an output coupler (OC) along an optical axis. The output coupler (OC) is optically connected to the output lens along the optical axis. A means for detecting atomic optical emission comprises a filter and a light detector. The optical filter is optically connected to the laser media and the optical detector. A control system is connected to the optical detector and the analysis electronics. The analysis electronics are optically connected to the output lens. The detection of the large scale laser output production triggers the control system to initiate the precise timing and data collection from the detector and analysis.

  9. Pulsed operation of a TEA CO{sub 2} laser under the conditions of the growth of an optical inhomogeneity of the active medium at high specific pump energies

    SciTech Connect

    Makarov, K N; Roerich, V C; Satov, Yu A; Stepanov, A E; Khomenko, S V

    2000-04-30

    A CO{sub 2} laser system with self-modulation of the intracavity losses was developed. This system was capable of generating efficiently pulses free of a radiation 'tail' typical for CO{sub 2} lasers. A simple method was used to detect the optical inhomogeneity of the medium of a gas-discharge TEA module. The results of the measurements are presented. (lasers)

  10. A Large Aperture, High Energy Laser System for Optics and Optical Component Testing

    SciTech Connect

    Nostrand, M C; Weiland, T L; Luthi, R L; Vickers, J L; Sell, W D; Stanley, J A; Honig, J; Auerbach, J; Hackel, R P; Wegner, P J

    2003-11-01

    A large aperture, kJ-class, multi-wavelength Nd-glass laser system has been constructed at Lawrence Livermore National Lab which has unique capabilities for studying a wide variety of optical phenomena. The master-oscillator, power-amplifier (MOPA) configuration of this ''Optical Sciences Laser'' (OSL) produces 1053 nm radiation with shaped pulse lengths which are variable from 0.1-100 ns. The output can be frequency doubled or tripled with high conversion efficiency with a resultant 100 cm{sup 2} high quality output beam. This facility can accommodate prototype hardware for large-scale inertial confinement fusion lasers allowing for investigation of integrated system issues such as optical lifetime at high fluence, optics contamination, compatibility of non-optical materials, and laser diagnostics.

  11. Optical response in a laser-driven quantum pseudodot system

    NASA Astrophysics Data System (ADS)

    Kilic, D. Gul; Sakiroglu, S.; Ungan, F.; Yesilgul, U.; Kasapoglu, E.; Sari, H.; Sokmen, I.

    2017-03-01

    We investigate theoretically the intense laser-induced optical absorption coefficients and refractive index changes in a two-dimensional quantum pseudodot system under an uniform magnetic field. The effects of non-resonant, monochromatic intense laser field upon the system are treated within the framework of high-frequency Floquet approach in which the system is supposed to be governed by a laser-dressed potential. Linear and nonlinear absorption coefficients and relative changes in the refractive index are obtained by means of the compact-density matrix approach and iterative method. The results of numerical calculations for a typical GaAs quantum dot reveal that the optical response depends strongly on the magnitude of external magnetic field and characteristic parameters of the confinement potential. Moreover, we have demonstrated that the intense laser field modifies the confinement and thereby causes remarkable changes in the linear and nonlinear optical properties of the system.

  12. CO2 laser beam propagation with ZnSe optics

    NASA Astrophysics Data System (ADS)

    Leong, K. H.; Liu, Yi; Holdridge, D. J.

    Beam propagation characteristics of ZnSe optics used in kiloWatt power CO2 laser aided material processing applications are determined using the Prometec Laser Beam Analyzer. The laser used was a Rofin Sinar RS6000 CO2 laser with mode aperturing. Beam power varied from 500W to 6300W and beam modes used were TEM(sub 00), TEM(sub 01), TEM(sub 10), and TEM(sub 20). Both transmissive and reflective optics were examined. The ZnSe lenses tested included meniscus, diffractive, and cylindrical lenses of 5 in. focal length and a 10 in. focal length integrating lens. Reflective optics included an integrator and a 5 in. focal length parabolic mirror for welding. Parameters obtained included beam propagation profiles, intensity profiles, depth of focus, spot size, and back focal length. A subset of the data obtained is presented here. Details of the work will appear in a full length paper.

  13. Active Stand-off Detection of Gas Leaks Using a Short Range Hard-target Backscatter Differential Optical Absorption System Based on a Quantum Cascade Laser Transmitter

    NASA Astrophysics Data System (ADS)

    Diaz, Adrian; Thomas, Benjamin; Castillo, Paulo; Gross, Barry; Moshary, Fred

    2016-06-01

    Fugitive gas emissions from agricultural or industrial plants and gas pipelines are an important environmental concern as they can contribute to the global increase of greenhouse gas concentration. Moreover, they are also a security and safety concern because of possible risk of fire/explosion or toxicity. This study presents gas concentration measurements using a quantum cascade laser open path system (QCLOPS). The system retrieves the pathaveraged concentration of N2O and CH4 by collecting the backscattered light from a scattering target. The gas concentration measurements have a high temporal resolution (68 ms) and are achieved at sufficient range (up to 40 m, ~ 130 feet) with a detection limit of 2.6 ppm CH4 and 0.4 ppm for N2O. Given these characteristics, this system is promising for mobile/multidirectional remote detection and evaluation of gas leaks. The instrument is monostatic with a tunable QCL emitting at ~ 7.7 μm wavelength range. The backscattered radiation is collected by a Newtonian telescope and focused on an infrared light detector. Puffs of N2O and CH4 are released along the optical path to simulate a gas leak. The measured absorption spectrum is obtained using the thermal intra-pulse frequency chirped DFB QCL and is analyzed to obtain path averaged gas concentrations.

  14. Laser Brazing metallic embedding technique for fiber optic sensors

    NASA Astrophysics Data System (ADS)

    Grandal, Tania; Fraga, Sergio; Castro, Gemma; Vazquez, Esteban; Zornoza, Ander

    2017-04-01

    In this paper a fiber optic metallic embedding technique is presented based on laser Brazing manufacturing process. The embedding strategy to follow by the laser Brazing, which consists in three steps, minimizes the thermal stress of the embedded fiber, relaxes microbending strains and reduces damage on the fiber. The minimum embedded fiber optic Ni coating total diameter is 237 μm for a successful process with negligible optical loss on the fiber. Fiber Bragg Gratings were successfully embedded in metallic specimens and their strain response was in accordance with their specifications.

  15. Propagation of Complex Laser Pulses in Optically Dense Media

    NASA Astrophysics Data System (ADS)

    Fetterman, M. R.; Davis, J. C.; Goswami, D.; Yang, W.; Warren, W. S.

    1999-05-01

    Ultrafast laser pulses with complex envelopes (amplitude and frequency modulated) are used to excite an optically dense column of rubidium vapor. Pulse reshaping, stimulated emission dynamics, and residual electronic excitation in the Rb vapor are all shown to depend strongly on the laser pulse shape. Pulses that produce adiabatic passage in the optically thin limit exhibit more complex behavior in optically thick samples, including an unexpected dependence on the sign of the frequency sweep. Numerical solutions of the Maxwell-Bloch equations are shown to account for our results.

  16. Control of light polarization using optically spin-injected vertical external cavity surface emitting lasers

    SciTech Connect

    Frougier, J. Jaffrès, H.; Deranlot, C.; George, J.-M.; Baili, G.; Dolfi, D.; Alouini, M.; Sagnes, I.; Garnache, A.

    2013-12-16

    We fabricated and characterized an optically pumped (100)-oriented InGaAs/GaAsP multiple quantum well Vertical External Cavity Surface Emitting Laser (VECSEL). The structure is designed to allow the integration of a Metal-Tunnel-Junction ferromagnetic spin-injector for future electrical injection. We report here the control at room temperature of the electromagnetic field polarization using optical spin injection in the active medium of the VECSEL. The switching between two highly circular polarization states had been demonstrated using an M-shaped extended cavity in multi-modes lasing. This result witnesses an efficient spin-injection in the active medium of the LASER.

  17. Laser transmitter assembly for the Optical Communication Demonstrator

    NASA Astrophysics Data System (ADS)

    Hemmati, Hamid; Copeland, David J.

    1994-08-01

    A modulated fiber-coupled diode laser assembly has been developed. This module will serve as the laser transmitter assembly for the Optical Communication Demonstrator (OCD) system. The laser is capable of greater than 20 mW of output at 100 Mbps Q-PPM modulation. It consists of a high-speed driver, a controller to maintain output amplitude under varying duty cycles, and a temperature controller to control output wavelength. The driver provides over 280 mA of peak modulation current with an optical pulse risetime of approximately 1 ns. The switching speed is limited by the inductance of the laser mount and the cable connecting the driver to the mount. The laser is coupled to a single-mode polarization preserving fiber that can feed directly into the telescope assembly of OCD.

  18. CO2 laser polishing of conical shaped optical fiber deflectors

    NASA Astrophysics Data System (ADS)

    Şimşek, Elif Uzcengiz; Şimşek, Bartu; Ortaç, Bülend

    2017-06-01

    A novel method for polishing conical shaped optical fiber deflectors by modulated CO2 laser exposure is reported. The conical shaped fiber deflector geometry was first formed with rough mechanical polishing, then it was exposed to modulated CO2 laser operating with wavelength at 10.6 µm to achieve fine polish surfaces. The motivation of this work is to demonstrate that the modulated CO2 laser exposure approach allows a fiber surface roughness at a nanometer scale without modifying the conical shape of the fiber deflector. The average surface roughness of mechanically polished fiber deflectors with 30 and 9 µm lapping films was smoothed down to 20.4 and 4.07 nm, respectively, after CO2 laser polishing process. By combining mechanical and laser polishing techniques, fabrication of conical shaped optical fiber deflectors takes less time and it becomes laborer independent and easy to apply.

  19. Optical fiber transmission of high power excimer laser radiation.

    PubMed

    Pini, R; Salimbeni, R; Vannini, M

    1987-10-01

    An experimental investigation of optical fiber transmission of high power excimer laser radiation is presented. Different types of commercially available UV fiber have been tested, measuring energy handling capabilities and transmission losses of short samples at the XeCl (308-nm) and KrF (249-nm) wavelengths by using a standard excimer laser. A power density dependent damage process has been observed over 1 GW/cm(2). Fiber losses due to different radii of curvature are also reported. Experimental results have been examined to evaluate the effectiveness of excimer laser transmission through optical fibers for such medical uses as laser angioplasty, including also a comparison between the use of KrF or XeCl emission lines for this purpose. Finally, optimum excimer laser characteristics to increase the energy coupling in fibers are discussed.

  20. Automatic laser glare suppression in electro-optical sensors.

    PubMed

    Ritt, Gunnar; Eberle, Bernd

    2015-01-05

    Progress in laser technology has led to very compact but nevertheless powerful laser sources. In the visible and near infrared spectral region, lasers of any wavelength can be purchased. Continuous wave laser sources pose an especially serious threat to the human eye and electro-optical sensors due to their high proliferation and easy availability. The manifold of available wavelengths cannot be covered by conventional safety measures like absorption or interference filters. We present a protection concept for electro-optical sensors to suppress dazzling in the visible spectral region. The key element of the concept is the use of a digital micromirror device (DMD) in combination with wavelength multiplexing. This approach allows selective spectral filtering in defined regions of interest in the scene. The system offers the possibility of automatic attenuation of dazzling laser radiation.

  1. Automatic Laser Glare Suppression in Electro-Optical Sensors

    PubMed Central

    Ritt, Gunnar; Eberle, Bernd

    2015-01-01

    Progress in laser technology has led to very compact but nevertheless powerful laser sources. In the visible and near infrared spectral region, lasers of any wavelength can be purchased. Continuous wave laser sources pose an especially serious threat to the human eye and electro-optical sensors due to their high proliferation and easy availability. The manifold of available wavelengths cannot be covered by conventional safety measures like absorption or interference filters. We present a protection concept for electro-optical sensors to suppress dazzling in the visible spectral region. The key element of the concept is the use of a digital micromirror device (DMD) in combination with wavelength multiplexing. This approach allows selective spectral filtering in defined regions of interest in the scene. The system offers the possibility of automatic attenuation of dazzling laser radiation. PMID:25569754

  2. EFFECTS OF LASER RADIATION ON MATTER. LASER PLASMA: Microwave generation in an optical breakdown plasma created by modulated laser radiation

    NASA Astrophysics Data System (ADS)

    Antipov, A. A.; Grasyuk, Arkadii Z.; Losev, Leonid L.; Soskov, V. I.

    1990-06-01

    It was established that when laser radiation, intensity modulated at a frequency of 2.2 GHz, interacted with an optical breakdown plasma which it had created, a microwave component appeared in the thermal emf of the plasma. The amplitude of the microwave thermal emf reached 0.7 V for a laser radiation intensity of 6 GW/cm2. Laser radiation with λL = 1.06 μm was converted to the microwave range with λmω = 13 cm in the optical breakdown plasma. A microwave signal power of ~ 0.5 W was obtained from a laser power of ~ 5 MW.

  3. The Adaptive Optics Summer School Laboratory Activities

    NASA Astrophysics Data System (ADS)

    Ammons, S. M.; Severson, S.; Armstrong, J. D.; Crossfield, I.; Do, T.; Fitzgerald, M.; Harrington, D.; Hickenbotham, A.; Hunter, J.; Johnson, J.; Johnson, L.; Li, K.; Lu, J.; Maness, H.; Morzinski, K.; Norton, A.; Putnam, N.; Roorda, A.; Rossi, E.; Yelda, S.

    2010-12-01

    Adaptive Optics (AO) is a new and rapidly expanding field of instrumentation, yet astronomers, vision scientists, and general AO practitioners are largely unfamiliar with the root technologies crucial to AO systems. The AO Summer School (AOSS), sponsored by the Center for Adaptive Optics, is a week-long course for training graduate students and postdoctoral researchers in the underlying theory, design, and use of AO systems. AOSS participants include astronomers who expect to utilize AO data, vision scientists who will use AO instruments to conduct research, opticians and engineers who design AO systems, and users of high-bandwidth laser communication systems. In this article we describe new AOSS laboratory sessions implemented in 2006-2009 for nearly 250 students. The activity goals include boosting familiarity with AO technologies, reinforcing knowledge of optical alignment techniques and the design of optical systems, and encouraging inquiry into critical scientific questions in vision science using AO systems as a research tool. The activities are divided into three stations: Vision Science, Fourier Optics, and the AO Demonstrator. We briefly overview these activities, which are described fully in other articles in these conference proceedings (Putnam et al., Do et al., and Harrington et al., respectively). We devote attention to the unique challenges encountered in the design of these activities, including the marriage of inquiry-like investigation techniques with complex content and the need to tune depth to a graduate- and PhD-level audience. According to before-after surveys conducted in 2008, the vast majority of participants found that all activities were valuable to their careers, although direct experience with integrated, functional AO systems was particularly beneficial.

  4. Experimental classification of dynamical regimes in optically injected lasers.

    PubMed

    O'Shea, D; Osborne, S; Blackbeard, N; Goulding, D; Kelleher, B; Amann, A

    2014-09-08

    We present a reliable and fast technique to experimentally categorise the dynamical state of optically injected two mode and single mode lasers. Based on the experimentally obtained time-traces locked, unlocked and chaotic states are distinguished for varying injection strength and detuning. For the two mode laser, the resulting experimental stability diagram provides a map of the various single mode and two mode regimes and the transitions between them. This stability diagram is in strong agreement with the theoretical predictions from low-dimensional dynamical models for two mode lasers. We also apply our method to the single mode laser and retain the close agreement between theory and experiment.

  5. Calculations of laser cavity dumping for optical communications

    NASA Technical Reports Server (NTRS)

    Robinson, D. L.; Rayman, M. D.

    1988-01-01

    For deep-space pulse-position modulation (PPM) optical communication links using Nd:YAG lasers, two types of laser transmitter modulation techniques are available for efficiently producing laser pulses over a broad range of repetition rates: Q-switching and cavity dumping. The desired modulation scheme is dependent on the required pulse repetition frequency and link parameters. These two techniques are discussed, theoretical and numerical calculations of the internal energy of the laser cavity in cavity dumping are described, and an example of cavity dumping is applied to a link for a proposed experiment package on Cassini.

  6. Nd-doped phosphate glass microstructured optical fiber laser

    NASA Astrophysics Data System (ADS)

    Zhang, G.; Luo, F. F.; Liu, X. F.; Dong, G. P.; Zhang, Q.; Lin, G.; Zhou, Q. L.; Qiu, J. R.; Hu, L. L.; Chen, D. P.

    2010-06-01

    We experimentally demonstrated a single-mode laser at 1056 nm with Nd-doped phosphate glass microstructured optical fiber (MOF), which was fabricated with conventional stack-and-draw method. The laser action was observed from a Fabry-Perot cavity formed by placing two dichroic mirrors of ˜100 and 85% reflectivity, to the two end facets of MOF. Pumped by CW laser diodes (LDs) at 808 nm, the MOF laser yielded a maximum output power of 8.5 mW and a slope efficiency of 2%.

  7. Optical bistability and multistability in an active interferometer.

    PubMed

    Ohtsubo, J; Liu, Y

    1990-07-01

    Optoelectronic hybrid bistability and multistability in an active interferometer using a laser diode are demonstrated experimentally. The active laser-diode interferometer is composed of a Twyman-Green interferometer with an electronic feedback circuit. By feeding back the interferometer output together with an external light input through a detector to control thelaser-diode injection current, the optical bistable and multistable states of the output power from the laser diode are observed. Bistable operation does not require cutoff or saturation in the amplifier. The theoretical background of the phenomena is discussed.

  8. High energy laser optics manufacturing: a preliminary study

    SciTech Connect

    Baird, E.D.

    1980-07-01

    This report presents concepts and methods, major conclusions, and major recommendations concerning the fabrication of high energy laser optics (HELO) that are to be machined by the Large Optics Diamond Turning Machine (LODTM) at the Lawrence Livermore National Laboratory (LLNL). Detailed discussions of concepts and methods proposed for metrological operations, polishing of reflective surfaces, mounting of optical components, construction of mirror substrates, and applications of coatings are included.

  9. Dibenzotetraaza [14] annulene materials for recordable blue laser optical disc

    NASA Astrophysics Data System (ADS)

    Bin, Yuejing; Zhao, Fuqun; Huang, Lei; Li, Zhongyu; Zhang, Fushi

    2008-03-01

    Phthalocyanine materials have successfully been applied in infrared ray optical disc systems. Seeking for the phthalocyanine-analogous materials with great conjugate macrocyclic π bond system is the key for new materials research of super high density blue laser optical storage. Dibenzotetraaza [14] annulene have the similar macrocyclic structure. It was used as a building block for the preparation of multi-component materials matched the requirement of recordable blue laser optical disc. Ester substituents have been generated with oxalyl dichloride (or phosgene) and appropriate HO-function-containing substrates. A range of new complexes equipped with ester groups derived from various alcohols and phenols have been prepared. The new products have been characterized by UV-Vis spectrometer, TGA, refractive index of the organic films. These kinds of materials have suitable light and thermal sensitivity, and it is a valuable material for blue laser optical storage.

  10. Parameters of the focusing optics in a laser thermonuclear reactor

    SciTech Connect

    Basov, N.G.; Belousov, N.I.; Vergunova, G.A.; Grishunin, P.A.; Danilov, A.E.; Lebo, I.G.; Rozanov, V.B.; Sklizkov, G.V.; Subbotin, V.I.; Fedotov, S.I.

    1985-03-01

    The energy balance of a laser thermonuclear reactor is considered and it is shown that the energy of the reaction products absorbed by the focusing optics of the reactor considerably exceeds the energy absorbed from the laser pulse. The x-ray spectrum of the target emission is calculated and used to find the minimum distances from the center of the chamber to the optical system. Variants of the gas shield are analyzed. The laser radiation brightness required to ignite the reaction is used to obtain a relationship between the minimum focal length and the optical strength of the material employed for the optics. It is shown that thermonuclear neutrons incident on the focusing system generate considerable thermal stresses and deformations.

  11. Theoretical model for a background noise limited laser-excited optical filter for doubled Nd lasers

    NASA Astrophysics Data System (ADS)

    Shay, Thomas M.; Garcia, Daniel F.

    1990-06-01

    A simple theoretical model for the calculation of the dependence of filter quantum efficiency versus laser pump power in an atomic Rb vapor laser-excited optical filter is reported. Calculations for Rb filter transitions that can be used to detect the practical and important frequency-doubled Nd lasers are presented. The results of these calculations show the filter's quantum efficiency versus the laser pump power. The required laser pump powers required range from 2.4 to 60 mW/sq cm of filter aperture.

  12. Theoretical model for a background noise limited laser-excited optical filter for doubled Nd lasers

    NASA Technical Reports Server (NTRS)

    Shay, Thomas M.; Garcia, Daniel F.

    1990-01-01

    A simple theoretical model for the calculation of the dependence of filter quantum efficiency versus laser pump power in an atomic Rb vapor laser-excited optical filter is reported. Calculations for Rb filter transitions that can be used to detect the practical and important frequency-doubled Nd lasers are presented. The results of these calculations show the filter's quantum efficiency versus the laser pump power. The required laser pump powers required range from 2.4 to 60 mW/sq cm of filter aperture.

  13. Integrated modeling of the GMT laser tomography adaptive optics system

    NASA Astrophysics Data System (ADS)

    Piatrou, Piotr

    2014-08-01

    Laser Tomography Adaptive Optics (LTAO) is one of adaptive optics systems planned for the Giant Magellan Telescope (GMT). End-to-end simulation tools that are able to cope with the complexity and computational burden of the AO systems to be installed on the extremely large telescopes such as GMT prove to be an integral part of the GMT LTAO system development endeavors. SL95, the Fortran 95 Simulation Library, is one of the software tools successfully used for the LTAO system end-to-end simulations. The goal of SL95 project is to provide a complete set of generic, richly parameterized mathematical models for key elements of the segmented telescope wavefront control systems including both active and adaptive optics as well as the models for atmospheric turbulence, extended light sources like Laser Guide Stars (LGS), light propagation engines and closed-loop controllers. The library is implemented as a hierarchical collection of classes capable of mutual interaction, which allows one to assemble complex wavefront control system configurations with multiple interacting control channels. In this paper we demonstrate the SL95 capabilities by building an integrated end-to-end model of the GMT LTAO system with 7 control channels: LGS tomography with Adaptive Secondary and on-instrument deformable mirrors, tip-tilt and vibration control, LGS stabilization, LGS focus control, truth sensor-based dynamic noncommon path aberration rejection, pupil position control, SLODAR-like embedded turbulence profiler. The rich parameterization of the SL95 classes allows to build detailed error budgets propagating through the system multiple errors and perturbations such as turbulence-, telescope-, telescope misalignment-, segment phasing error-, non-common path-induced aberrations, sensor noises, deformable mirror-to-sensor mis-registration, vibration, temporal errors, etc. We will present a short description of the SL95 architecture, as well as the sample GMT LTAO system simulation

  14. New, Efficient Optically Pumped Solid State Lasers.

    DTIC Science & Technology

    1986-12-10

    Alexander J. Pertica , now at Lawrence Livermore National Lab., University of California, Livermore, CA 94550, "Laser Material Characteristics of Ti:Al...0 803 806 809 812 PUMP DIODE WAVELENGTH (nm) Laser Material Characteristics of Ti:AI0 3 Milton Bimbaum Alexander J. Pertica Center for Laser Studies...intrinsic material losses and to aid In the attempts to produce homogeneous and low loss Ti:AIO,. Bimbaum and Pertica -"Laowr... Characteristics of TI:A1230

  15. Femtosecond laser microhole drilling inside a fused silica optical fiber with optical inner surface quality

    NASA Astrophysics Data System (ADS)

    Shiraishi, Masahiko; Goya, Kenji; Nishiyama, Michiko; Kubodera, Shoichi; Watanabe, Kazuhiro

    2016-09-01

    We have demonstrated femtosecond laser microhole drilling inside a fused silica optical fiber with optical inner surface quality. An optical quality microhole with a diameter of 3 μ m and a length of approximately 35 μ m was produced inside an optical fiber of a cladding diameter of 125 μ m. The microhole drilling inside an optical fiber was caused as a result of plasma filamentation of focused femtosecond laser irradiation at a wavelength of 400 nm. The size of the microhole was reproduced with a ray trace of the focused laser beam with consideration of self-focusing. The optical quality of the microhole was verified by measuring the transmittance of 94 % of infrared diode emission.

  16. Optical Probes for Laser Induced Shocks

    DTIC Science & Technology

    1992-03-01

    waves generated by a laser -induced plasma were investigated using a pump - and-probe technique. Both 7-ns and 40-ps laser pulses at 1.06 gIm were employed...what follows, a TEM00 the time it takes to ablate a layer of thickness 60, i.e., the laser beam is assumed. To describe this I apply the results...Frauchiger and W. Liithy, Opt. Quantum Electron. 19, 231 (1987). transverse the irradiated spot during the laser pulse, as is ’It should read i 10(dv

  17. Optical feedback-induced light modulation for fiber-based laser ablation.

    PubMed

    Kang, Hyun Wook

    2014-11-01

    Optical fibers have been used as a minimally invasive tool in various medical fields. However, due to excessive heat accumulation, the distal end of a fiber often suffers from severe melting or devitrification, leading to the eventual fiber failure during laser treatment. In order to minimize thermal damage at the fiber tip, an optical feedback sensor was developed and tested ex vivo. Porcine kidney tissue was used to evaluate the feasibility of optical feedback in terms of signal activation, ablation performance, and light transmission. Testing various signal thresholds demonstrated that 3 V was relatively appropriate to trigger the feedback sensor and to prevent the fiber deterioration during kidney tissue ablation. Based upon the development of temporal signal signatures, full contact mode rapidly activated the optical feedback sensor possibly due to heat accumulation. Modulated light delivery induced by optical feedback diminished ablation efficiency by 30% in comparison with no feedback case. However, long-term transmission results validated that laser ablation assisted with optical feedback was able to almost consistently sustain light delivery to the tissue as well as ablation efficiency. Therefore, an optical feedback sensor can be a feasible tool to protect optical fiber tips by minimizing debris contamination and delaying thermal damage process and to ensure more efficient and safer laser-induced tissue ablation.

  18. Optically pumped oxygen-iodine laser

    NASA Astrophysics Data System (ADS)

    Zagidullin, Marsel V.; Malyshev, Mikhail S.

    2017-01-01

    A novel optical pumping scheme considering a two-step irradiation by light at wavelengths near 500 nm and 1315 nm is proposed in this work. Radiation at 500 nm is used to dissociate about 1% of iodine molecules. The radiation at 1315 nm excites atomic iodine to the 2P1/2 state. Singlet oxygen molecules are produced via the energy exchange process I(2P1/2)+O2(X3Σ)-> I(2P3/2)+O2(a1Δ), while I(2P1/2)+O2(a1Δ) energy pooling produces b1Σ oxygen. I(2P3/2) and O2(1Σ) then accelerate the dissociation of I2. After gas dynamic cooling in supersonic nozzle, active medium may reach 100 W cm-2 and small signal gain of 0.01 cm-1.

  19. Beam shaping for laser-based adaptive optics in astronomy.

    PubMed

    Béchet, Clémentine; Guesalaga, Andrés; Neichel, Benoit; Fesquet, Vincent; González-Núñez, Héctor; Zúñiga, Sebastián; Escarate, Pedro; Guzman, Dani

    2014-06-02

    The availability and performance of laser-based adaptive optics (AO) systems are strongly dependent on the power and quality of the laser beam before being projected to the sky. Frequent and time-consuming alignment procedures are usually required in the laser systems with free-space optics to optimize the beam. Despite these procedures, significant distortions of the laser beam have been observed during the first two years of operation of the Gemini South multi-conjugate adaptive optics system (GeMS). A beam shaping concept with two deformable mirrors is investigated in order to provide automated optimization of the laser quality for astronomical AO. This study aims at demonstrating the correction of quasi-static aberrations of the laser, in both amplitude and phase, testing a prototype of this two-deformable mirror concept on GeMS. The paper presents the results of the preparatory study before the experimental phase. An algorithm to control amplitude and phase correction, based on phase retrieval techniques, is presented with a novel unwrapping method. Its performance is assessed via numerical simulations, using aberrations measured at GeMS as reference. The results predict effective amplitude and phase correction of the laser distortions with about 120 actuators per mirror and a separation of 1.4 m between the mirrors. The spot size is estimated to be reduced by up to 15% thanks to the correction. In terms of AO noise level, this has the same benefit as increasing the photon flux by 40%.

  20. Holographic optical system for aberration corrections in laser Doppler velocimetry

    NASA Technical Reports Server (NTRS)

    Kim, R. C.; Case, S. K.; Schock, H. J.

    1985-01-01

    An optical system containing multifaceted holographic optical elements (HOEs) has been developed to correct for aberrations introduced by nonflat windows in laser Doppler velocimetry. The multifacet aberration correction approach makes it possible to record on one plate many sets of adjacent HOEs that address different measurement volume locations. By using 5-mm-diameter facets, it is practical to place 10-20 sets of holograms on one 10 x 12.5-cm plate, so that the procedure of moving the entire optical system to examine different locations may not be necessary. The holograms are recorded in dichromated gelatin and therefore are nonabsorptive and suitable for use with high-power argon laser beams. Low f-number optics coupled with a 90-percent efficient distortion-correcting hologram in the collection side of the system yield high optical efficiency.

  1. Silver nanoprisms/silicone hybrid rubber materials and their optical limiting property to femtosecond laser

    NASA Astrophysics Data System (ADS)

    Li, Chunfang; Liu, Miao; Jiang, Nengkai; Wang, Chunlei; Lin, Weihong; Li, Dongxiang

    2017-08-01

    Optical limiters against femtosecond laser are essential for eye and sensor protection in optical processing system with femtosecond laser as light source. Anisotropic Ag nanoparticles are expected to develop into optical limiting materials for femtosecond laser pulses. Herein, silver nanoprisms are prepared and coated by silica layer, which are then doped into silicone rubber to obtain hybrid rubber sheets. The silver nanoprisms/silicone hybrid rubber sheets exhibit good optical limiting property to femtosecond laser mainly due to nonlinear optical absorption.

  2. Electro-optic and Acousto-optic Laser Beam Scanners

    NASA Astrophysics Data System (ADS)

    Römer, G. R. B. E.; Bechtold, P.

    Optical solid state deflectors rely on the electro-optical or acousto-optic effect. These Electro-Optical Deflectors (EODs) and Acousto-Optical Deflectors (AODs) do not contain moving parts and therefore exhibit high deflection velocities and are free of drawbacks associated with mechanical scanners. A description of the principles of operation of EODs and AODs is presented. In addition, characteristics, properties and the (dis)advantages of EODs and AODs, when compared to mirror based mechanical deflectors, is discussed. Deflection angles, speed and accuracy are discussed in terms of resolvable spots and related quantities. Also, response time, damage threshold, efficiency and the type and magnitude of beam distortions is addressed. Optical deflectors are characterized by high angular deflection velocities, but small deflection angles. Whereas mechanical mechanical scanners are characterized by relatively small deflection velocities, but large deflection angles. Arranging an optical deflector and a mechanical scanner in series allows to take advantage of the best of both worlds.

  3. Laser beam shaping optical system design methods and their application in edge-emitting semiconductor laser-based LIDAR systems

    NASA Astrophysics Data System (ADS)

    Serkan, Mert

    LIDAR (Light Detection And Ranging) systems are employed for numerous applications such as remote sensing, military applications, optical data storage, display technology, and material processing. Furthermore, they are superior to other active remote sensing tools such as RADAR systems, considering their higher accuracy and more precise resolution due to their much shorter wavelengths and narrower beamwidth. Several types of lasers can be utilized as the radiation source of several LIDAR systems. Semiconductor laser-based LIDAR systems have several advantages such as low cost, compactness, broad range of wavelengths, and high PRFs (Pulse Repetition Frequency). However, semiconductor lasers have different origins and angles of divergence in the two transverse directions, resulting in the inherent astigmatism and elliptical beam shape. Specifically, elliptical beam shape is not desirable for several laser-based applications including LIDAR systems specifically designed to operate in the far-field region. In this dissertation, two mirror-based and two lens-based beam shapers are designed to circularize, collimate, and expand an edge-emitting semiconductor laser beam to a desired beam diameter for possible application in LIDAR systems. Additionally, most laser beams including semiconductor laser beams have Gaussian irradiance distribution. For applications that require uniform illumination of an extended target area, Gaussian irradiance distribution is undesirable. Therefore, a specific beam shaper is designed to transform the irradiance distribution from Gaussian to uniform in addition to circularizing, collimating, and expanding the semiconductor laser beam. For the design of beam shapers, aperture sizes of the surfaces are preset for desired power transmission and allowed diffraction level, surface parameters of the optical components and the distances between these surfaces are determined. Design equations specific to these beam shaping optical systems are

  4. Collimation optics for high power blue laser diodes

    NASA Astrophysics Data System (ADS)

    Huber, M.; Forrer, H.; Wuest, P.; Moser, H.; Forrer, M.

    2017-02-01

    Similar to the well-established high power laser diodes in the infrared wavelength range, the laser diodes in the blue wavelength range require tailored optics for beam shaping, to make the light usable for a variety of applications. High power laser diode arrays or single emitters require fast and slow axis optical collimation for further transport or photonics applications using high power laser radiation. With increasing requirements in higher brightness for slow axis collimation different engineering solutions exist. By using novel production technologies, e.g. precision molding, approaches that were considered too expensive for mass production become available to broad application fields. Here we report about the benefits of molded refractive, freeform slow axis collimation optics and compare them to the ubiquitous standard circular cylindrical, as well as acircular cylindrical slow axis collimation optics. By using refractive free form slow axis collimation optics it is possible to achieve significantly better brightness compared to circular cylindrical or acircular cylindrical slow axis collimation optics.

  5. Semiconductor Laser Complex Dynamics: From Optical Neurons to Optical Rogue Waves

    DTIC Science & Technology

    2017-02-11

    laser dynamics for innovative applications . The results of the project were published in 5 high- impact journal papers and were presented as invited or...stochastic phenomena and ii) to exploit the laser dynamics for innovative applications . The results of the project were published in 5 high-impact...optics communi- cations, optical data storage, life sciences applications , material processing and sensing. They have a huge economic impact and are

  6. Effect of Laser Irradiation on Enzyme Activity

    NASA Astrophysics Data System (ADS)

    Murakami, Satoshi; Kashii, Masafumi; Kitano, Hiroshi; Adachi, Hiroaki; Takano, Kazufumi; Matsumura, Hiroyoshi; Inoue, Tsuyoshi; Mori, Yusuke; Doi, Masaaki; Sugamoto, Kazuomi; Yoshikawa, Hideki; Sasaki, Takatomo

    2005-11-01

    We previously developed a protein crystallization technique using a femtosecond laser and protein crystal processing and detaching techniques using a pulsed UV laser. In this study, we examine the effect of laser irradiation on protein integrity. After several kinds of laser were irradiated on part of a solution of glycerol-6-phosphate dehydrogenase from Leuconostoc mesenteroides, we measured the enzyme activity. Femtosecond and deep-UV laser irradiations have little influence on the whole enzyme activity, whereas the enzyme lost its activity upon high-power near-infrared laser irradiation at a wavelength of 1547 nm. These results suggest that suitable laser irradiation has no remarkable destructive influence on protein crystallization or crystal processing.

  7. UV laser with an acousto-optic intra-cavity control for GaN-sapphire cut

    NASA Astrophysics Data System (ADS)

    Gradoboev, Yury G.; Kazaryan, Mishik A.; Mokrushin, Yury M.; Shakin, Oleg V.

    2012-09-01

    A copper vapor laser is proposed as the basic component of the installation for processing of sapphire substrates with a GaN-coating. Laser radiation is transformed to UV range by optical frequency doubling. Powerful UV lasers are prospective tools for crystal cutting, photolithography and recording of the fiber Bragg gratings. The proposed approach is more promising in comparison with the use of excimer radiation because of instabilities of excimer laser generation and low coherence of its radiation, which makes difficult precise focusing and using interference pattern of UV radiation for exposing materials. UV laser based on second harmonic radiation of copper vapors laser has been designed. The UV laser system of high operation stability has been developed with output power 1 W at wavelengths 255.5 nm, 271.1 nm, 289.1 nm and coherence length radiation about 4 cm. The original intra-cavity acousto-optic control of output radiation is developed. It is allows adjusting frequency and on-off time ratio of output laser pulses with high accuracy. The stable heat regime was achieved for an active element of copper vapor laser̤ The laser system allows to select an optimum mode of ultra-violet radiation exposition for production of different optical elements. Intra-cavity acousto-optic cell was used for controlling of single pulse amplitude and number of pulses without any power supply tuning providing the stable operation of the laser system.

  8. Current and future activities in the area of optical space communications in Japan

    NASA Astrophysics Data System (ADS)

    Fujise, Masayuki; Araki, Ken'ichi; Arikawa, Hiroshi; Furuhama, Yoji

    1991-05-01

    An account is given of current and prospective activities in Japan in the field of optical space communications (OSC) and its associated optical technologies. These activities are conducted by NASDA, the Advanced Telecommunications Research Institute, and the Ministry of Posts and Telecommunications. Attention is given to such initiatives as high-precision tracking, bidirectional OSC, laser beam propagation, optical ground stations, and a free-space simulator for laser transmission.

  9. Actively Q-switched Raman fiber laser

    NASA Astrophysics Data System (ADS)

    Kuznetsov, A. G.; Podivilov, E. V.; Babin, S. A.

    2015-03-01

    A new scheme providing actively Q-switched operation of a Raman fiber laser (RFL) has been proposed and tested. The RFL consists of a 1 km single-mode fiber with a switchable loop mirror at one end and an angled cleaved output end. An 1080 nm pulse with microsecond duration is generated at the output by means of acousto-optic switching of the mirror at ~30 kHz in the presence of 6 W backward pumping at 1030 nm. In the proposed scheme, the generated pulse energy is defined by the pump energy distributed along the passive fiber, which amounts to 30 μJ in our case. The available pump energy may be increased by means of fiber lengthening. Pulse shortening is also expected.

  10. Active alignment and reliable pigtailing of laser diode transmitter

    NASA Astrophysics Data System (ADS)

    Fadhali, M.; Saktioto, .; Zainal, J.; Munajat, Y.; Ali, J.; Rahman, R.

    2008-09-01

    In this paper we present theoretical and experimental analysis on Nd:YAG laser microwelding for pigtailing laser diode transmitter through two ball lenses that are employed for effectively matching the elliptical mode field of the laser diode with the circular on of the single mode fiber. The fiber attachment and the fixing of various coupling components have been performed in what is so called active alignment process. The system continues measuring the coupled power during the processes of alignment and attachment of various coupling components as well as the working distance and misalignment tolerances optimizations. Results of theoretical modeling of laser weld penetration depth agree with the experimentally measured results in the low laser pulse energy range. Moreover the laser pulse parameters such as, duration, energy, number of pulse shoots as well as the focusing position over the workpiece and angle of laser pulse incidence are found to have very significant effects on the weld yields and greatly affect the laser weld depth to width ratio. Optimization of all the mentioned parameters found to be necessary for achieving strong laser microwelds with more penetration and less width in the attachments of the sensitive optical components inside the packaged photonic devices modules.

  11. Active learning in optics and photonics: Fraunhofer diffraction

    NASA Astrophysics Data System (ADS)

    Ghalila, H.; Ben Lakhdar, Z.; Lahmar, S.; Dhouaidi, Z.; Majdi, Y.

    2014-07-01

    "Active Learning in Optics and Photonics" (ALOP), funded by UNESCO within its Physics Program framework with the support of ICTP (Abdus Salam International Centre for Theoretical Physics) and SPIE (Society of Photo-Optical Instrumentation Engineers), aimed to helps and promotes a friendly and interactive method in teaching optics using simple and inexpensive equipment. Many workshops were organized since 2005 the year when Z. BenLakhdar, whom is part of the creators of ALOP, proposed this project to STO (Société Tunisienne d'Optique). These workshops address several issues in optics, covering geometrical optics, wave optics, optical communication and they are dedicated to both teachers and students. We focus this lecture on Fraunhofer diffraction emphasizing the facility to achieve this mechanism in classroom, using small laser and operating a slit in a sheet of paper. We accompany this demonstration using mobile phone and numerical modeling to assist in the analysis of the diffraction pattern figure.

  12. New, Efficient Optically Pumped Solid State Lasers.

    DTIC Science & Technology

    1989-02-21

    Lasers", during the contract period from 15 August 1984 thru 11 November 1988 (AFOSR-88-0378) has led to some notable advances. This effort h,.s focused...lower laser states of both Er and 1Ho. This work has led to the inves t igation of the Nd,Er ion-ion interactions in other crystals such as Nd,Er:YALO...backed pyrex reflector. While the laser may work in a gold-plated cavity, the many visible, blue and near uv pump bands suggest better efficiency is

  13. EIGENMODE ANALYSIS OF OPTICAL GUIDING IN FREE ELECTRON LASERS

    SciTech Connect

    Xie, M.; Deacon, D.A.G.; Madey, J.M.J.

    1989-03-01

    The spatial properties of the optical field and hence the performance of a free electron laser depend on the fact that the electron beam, which acts as both an amplifying and a refractive medium, is transversely nonuniform. Under certain circumstances, optical guiding may be realized, where the optical field is stably confined near the electron beam and amplified along the beam over many Rayleigh ranges. We show that the three-dimensional evolution of the optical field through the interaction region can be determined by a guided mode expansion before saturation. Optical guiding occurs when the fundamental growing mode becomes dominant. The guided mode expansion is made possible by implementing the biorthogonality of the eigenmodes of the coupled electron-beam-optical-wave system. The eigenmodes are found to be of vectorial form with three components; one specifies the guided optical mode and the other two describe the density and the energy modulations of the electron beam.

  14. Fiber optics interface for a dye laser oscillator and method

    DOEpatents

    Johnson, Steve A.; Seppala, Lynn G.

    1986-01-01

    A dye laser oscillator in which one light beam is used to pump a continuous tream of dye within a cooperating dye chamber for producing a second, different beam is generally disclosed herein along with a specific arrangement including an optical fiber and a fiber optics interface for directing the pumping beam into the dye chamber. The specific fiber optics interface illustrated includes three cooperating lenses which together image one particular dimension of the pumping beam into the dye chamber from the output end of the optical fiber in order to insure that the dye chamber is properly illuminated by the pumping beam.

  15. Computer optics and photonics for students of laser engineering disciplines

    NASA Astrophysics Data System (ADS)

    Zakharov, V. P.

    2005-10-01

    The concept of teaching in optics and photonics for undergraduate and post-graduate students of laser engineering disciplines are discussed. The designed curriculum include as fundamental knowledge on modern mathematics, physics and computer methods as up-to-date industrial optical engineering software training. Distributed Web-server technology with Alpha cluster station background allow to support real-time training and teaching with a set of computer optical laboratories, which are used as a framework for most university special courses. Remote access to facilities of Russian Academy of Science make it possible to accumulate modern science achievements in optical education.

  16. Fiber optics interface for a dye laser oscillator and method

    DOEpatents

    Johnson, S.A.; Seppala, L.G.

    1984-06-13

    A dye laser oscillator in which one light beam is used to pump a continuous stream of dye within a cooperating dye chamber for producing a second, different beam is generally disclosed herein along with a specific arrangement including an optical fiber and a fiber optics interface for directing the pumping beam into the dye chamber. The specific fiber optics interface illustrated includes three cooperating lenses which together image one particular dimension of the pumping beam into the dye chamber from the output end of the optical fiber in order to insure that the dye chamber is properly illuminated by the pumping beam.

  17. Precise, controlled laser delivery with evanescent optical waves.

    PubMed

    Hooper, B A; Domankevitz, Y; Lin, C P; Anderson, R R

    1999-09-01

    Precise laser surgery is possible with laser pulses at wavelengths that are strongly absorbed at the surface of tissue. However, pulses at these wavelengths (far UV, far infrared) are not compatible with fiber-optic transmission, making endoscopic surgical procedures inside the body difficult. We use evanescent optical waves to demonstrate an alternative for confining energy near the tissue surface. Precise, superficial tissue ablation is achieved with evanescent waves generated at a sapphire-tissue interface by a free-electron laser, where the ablation depth may be varied. A new class of precise, controlled laser surgical tools may be achieved in this novel approach for use in endoscopic procedures. Electromagnetic theory governing evanescent-wave tissue ablation is presented.

  18. Acousto-optic laser projection systems for displaying TV information

    SciTech Connect

    Gulyaev, Yu V; Kazaryan, M A; Mokrushin, Yu M; Shakin, O V

    2015-04-30

    This review addresses various approaches to television projection imaging on large screens using lasers. Results are presented of theoretical and experimental studies of an acousto-optic projection system operating on the principle of projecting an image of an entire amplitude-modulated television line in a single laser pulse. We consider characteristic features of image formation in such a system and the requirements for its individual components. Particular attention is paid to nonlinear distortions of the image signal, which show up most severely at low modulation signal frequencies. We discuss the feasibility of improving the process efficiency and image quality using acousto-optic modulators and pulsed lasers. Real-time projectors with pulsed line imaging can be used for controlling high-intensity laser radiation. (review)

  19. ARGOS - the Laser Star Adaptive Optics for LBT

    NASA Astrophysics Data System (ADS)

    Rabien, S.; Barl, L.; Beckmann, U.; Blümchen, T.; Bonaglia, M.; Borelli, J. L.; Brynnel, J.; Busoni, L.; Carbonaro, L.; Conot, C.; Davies, R.; Deysenroth, M.; Durney, O.; Elberich, M.; Esposito, S.; Gasho, V.; Gässler, W.; Gemperlein, H.; Genzel, R.; Green, R.; Haug, M.; Lloyd Hart, M.; Hubbard, P.; Kanneganti, S.; Kulas, M.; Noenickx, J.; Peter, D.; Quirrenbach, A.; Rademacher, M.; Rix, H. W.; Salinari, P.; Schwab, C.; Storm, J.; Strüder, L.; Thiel, M.; Weigelt, G.; Ziegleder, J.; de Xivry, G. Orban

    2011-09-01

    We will present the design and status of ARGOS - the Laser Guide Star adaptive optics facility for the Large Binocular Telescope. By projecting a constellation of multiple laser guide stars above each of the 8.4m primary mirrors of the LBT, ARGOS in its ground layer mode will enable a wide field adaptive optics correction for multi object spectroscopy. ARGOS implements high power pulsed green lasers and makes use of Rayleigh scattering for the guide star creation. The geometric relations of this setup in guide star height vs. primary diameter are quite comparable to an ELT with sodium guide stars. The use of LBT's adaptive secondary mirror, gated wavefront sensors, a prime focus calibration system and the laser constellation shows several aspects that may be used as pathfinding technology for the planned ELTs. In already planned upgrade steps with a hybrid Sodium-Rayleigh combination ARGOS will enable MCAO and MOAO implementations at LBT allowing unique astronomical observations.

  20. Spectral selectivity in optical fiber capillary dye lasers.

    PubMed

    Mobini, Esmaeil; Abaie, Behnam; Peysokhan, Mostafa; Mafi, Arash

    2017-05-01

    We explore the spectral properties of a capillary dye laser in the highly multimode regime. Our experiments indicate that the spectral behavior of the laser does not conform to a simple Fabry-Perot (FP) analysis; rather, it is strongly dictated by a Vernier resonant mechanism involving multiple modes, which propagate with different group velocities. The laser operates over a very broad spectral range and the Vernier effect gives rise to a free spectral range, which is orders of magnitude larger than that expected from a simple FP mechanism. The theoretical calculations presented confirm the experimental results. Propagating modes of the capillary fiber are calculated using the finite-element method and it is shown that the optical path lengths resulting from simultaneous beatings of these modes are in close agreement with the optical path lengths directly extracted from the Fourier transform of the experimentally measured laser emission spectra.

  1. Laser Pulse-Stretching Using Multiple Optical Ring-Cavities

    NASA Technical Reports Server (NTRS)

    Kojima, Jun; Nguyen, Quang-Viet; Lee, Chi-Ming (Technical Monitor)

    2002-01-01

    We describe a simple and passive nanosecond-long (ns-long) laser 'pulse-stretcher' using multiple optical ring-cavities. We present a model of the pulse-stretching process for an arbitrary number of optical ring-cavities. Using the model, we optimize the design of a pulse-stretcher for use in a spontaneous Raman scattering excitation system that avoids laser-induced plasma spark problems. From the optimized design, we then experimentally demonstrate and verify the model with a 3-cavity pulse-stretcher system that converts a 1000 mJ, 8.4 ns-long input laser pulse into an approximately 75 ns-long (FWHM) output laser pulse with a peak power reduction of 0.10X, and an 83% efficiency.

  2. Femtosecond fibre laser stabilisation to an optical frequency standard using a KTP electro-optic crystal

    SciTech Connect

    Nyushkov, B N; Pivtsov, V S; Koliada, N A; Kaplun, A B; Meshalkin, A B

    2015-05-31

    A miniature intracavity KTP-based electro-optic phase modulator has been developed which can be used for effective stabilisation of an optical frequency comb of a femtosecond erbiumdoped fibre laser to an optical frequency standard. The use of such an electro-optic modulator (EOM) has made it possible to extend the working frequency band of a phase-locked loop system for laser stabilisation to several hundred kilohertz. We demonstrate that the KTP-based EOM is sufficiently sensitive even at a small optical length, which allows it to be readily integrated into cavities of femtosecond fibre lasers with high mode frequency spacings (over 100 MHz). (extreme light fields and their applications)

  3. Optical injection enables coherence resonance in quantum-dot lasers

    NASA Astrophysics Data System (ADS)

    Ziemann, D.; Aust, R.; Lingnau, B.; Schöll, E.; Lüdge, K.

    2013-07-01

    We demonstrate that optically injected semiconductor quantum-dot lasers operated in the frequency-locked regime exhibit the counterintuitive effect of coherence resonance, i.e., the regularity of noise-induced spiking is a non-monotonic function of the spontaneous emission noise, and it is optimally correlated at a non-zero value of the noise intensity. We uncover the mechanism of coherence resonance from a microscopically based model of the quantum-dot laser structure, and show that it is related to excitability under optical injection and to a saddle-node infinite period (SNIPER) bifurcation occurring for small injection strength at the border of the frequency locking regime. By a model reduction we argue that the phenomenon of coherence resonance is generic for a wide class of optically injected lasers.

  4. Multifunctional optical correlator for picosecond ultraviolet laser pulse measurement

    DOE PAGES

    Rakhman, Abdurahim; Wang, Yang; Garcia, Frances; ...

    2014-01-01

    A compact optical correlator system that measures both the autocorrelation between two infrared (IR) lights and the cross-correlation between an IR and an ultraviolet (UV) light using a single nonlinear optical crystal has been designed and experimentally demonstrated. The rapid scanning of optical delay line, switching between auto and cross-correlations, crystal angle tuning, and data acquisition and processing are all computer controlled. Pulse widths of an IR light from a mode-locked laser are measured by the correlator and the results are compared with a direct measurement using a high-speed photodetector system. The correlator has been used to study the parametermore » dependence of the pulse width of a macropulse UV laser designed for laser-assisted hydrogen ion (H-) beam stripping for the Spallation Neutron Source at Oak Ridge National Laboratory.« less

  5. Improve power conversion efficiency of slab coupled optical waveguide lasers.

    PubMed

    Fan, Jiahua; Zhu, Lin; Dogan, Mehmet; Jacob, Jonah

    2014-07-28

    The slab coupled optical waveguide laser (SCOWL) is a promising candidate for high power, single mode emitter for a number of reasons, including its near diffraction limited optical quality, large modal size and near circular output pattern. Current SCOWL designs have limited electrical-optical power conversion efficiency (PCE) around 40%, which is lower than conventional RWG laser and broad area laser that are known to have much higher PCEs. To improve the SCOWL PCE, we theoretically optimize its structure by reducing Al content, increasing doping concentration and introducing a GRIN layer to prevent carrier leakage. Numerical simulations predict that an optimized SCOWL design has a maximum PCE of about 57% at room temperature.

  6. Multifunctional optical correlator for picosecond ultraviolet laser pulse measurement

    SciTech Connect

    Rakhman, Abdurahim; Wang, Yang; Garcia, Frances; Long, Cary D.; Huang, Chunning; Takeda, Yasuhiro; Liu, Yun

    2014-01-01

    A compact optical correlator system that measures both the autocorrelation between two infrared (IR) lights and the cross-correlation between an IR and an ultraviolet (UV) light using a single nonlinear optical crystal has been designed and experimentally demonstrated. The rapid scanning of optical delay line, switching between auto and cross-correlations, crystal angle tuning, and data acquisition and processing are all computer controlled. Pulse widths of an IR light from a mode-locked laser are measured by the correlator and the results are compared with a direct measurement using a high-speed photodetector system. The correlator has been used to study the parameter dependence of the pulse width of a macropulse UV laser designed for laser-assisted hydrogen ion (H-) beam stripping for the Spallation Neutron Source at Oak Ridge National Laboratory.

  7. Measurements and simulations of the optical gain and anti-reflection coating modal reflectivity in quantum cascade lasers with multiple active region stacks

    SciTech Connect

    Bidaux, Y.; Terazzi, R.; Bismuto, A.; Gresch, T.; Blaser, S.; Muller, A.; Faist, J.

    2015-09-07

    We report spectrally resolved gain measurements and simulations for quantum cascade lasers (QCLs) composed of multiple heterogeneous stacks designed for broadband emission in the mid-infrared. The measurement method is first demonstrated on a reference single active region QCL based on a double-phonon resonance design emitting at 7.8 μm. It is then extended to a three-stack active region based on bound-to-continuum designs with a broadband emission range from 7.5 to 10.5 μm. A tight agreement is found with simulations based on a density matrix model. The latter implements exhaustive microscopic scattering and dephasing sources with virtually no fitting parameters. The quantitative agreement is furthermore assessed by measuring gain coefficients obtained by studying the threshold current dependence with the cavity length. These results are particularly relevant to understand fundamental gain mechanisms in complex semiconductor heterostructure QCLs and to move towards efficient gain engineering. Finally, the method is extended to the measurement of the modal reflectivity of an anti-reflection coating deposited on the front facet of the broadband QCL.

  8. Transverse mode tailoring in diode lasers based on coupled large optical cavities

    NASA Astrophysics Data System (ADS)

    Gordeev, N. Yu; Maximov, M. V.; E Zhukov, A.

    2017-08-01

    The key principles of transverse mode engineering in edge-emitting lasers with broadened waveguides based on coupled large optical cavity (CLOC) structures are presented. The CLOC laser design is shown to be an effective approach for reducing the optical loss, broadening the waveguide, and lowering the beam divergence. Having simulated the sensitivity of the CLOC design to variations in layer thicknesses and compositions we have shown its high robustness. Advanced versions of the CLOC laser structures having two extra passive waveguides have been treated and shown to effectively eliminate several transverse modes. We have considered an application of the CLOC concept for waveguides with shifted active regions aimed at reducing laser thermal and electric resistances.

  9. Generation of Non-Uniform Pulses by an Eight Microstructured Optical Fiber Laser

    NASA Astrophysics Data System (ADS)

    Ennejah, Tarek; Bahloul, Faouzi; Attia, Rabah

    2011-06-01

    Mode locking mechanisms in fiber laser have been an active and rich research field in optical communication. In this paper we study the behaviour of an 8FL (eight fiber laser) totally made out of MOF (Microstructured Optical Fiber). We demonstrate that even output from a fiber laser is not necessarily uniform. Due to its ring cavity and NALM (Non linear Amplifying Loop Mirror) transmission properties, the laser generates randomly different non-uniform output pulses. It follows three states of operation: single, bound and multiple pulses were observed. We report the formation of bound pulses where side peaks are higher than the central one. We report also the formation of bound and multiple pulses which damage their bindings and alter their pulses width and separations.

  10. Fiber Optically Coupled Eyesafe Laser Threat Warning System

    DTIC Science & Technology

    2000-05-11

    WARNING SYSTEM 11 MAY 2000 MSS SPECIALTY GROUP ON INFRARED COUNTERMEASURES NAVAL POSTGRADUATE SCHOOL, MONTEREY, CA PRESENTED BY: DR. AL TORRES...A Dates Covered (from... to) - Title and Subtitle Fiber Optically Coupled Eyesafe Laser Threat Warning System Contract Number Grant Number... WARNING SYSTEM (ESLTWS) PHASE II SBIR PROGRAM • CONCEPT: - TO DEVELOP A UNIQUE AND NOVEL EYE SAFE LASER THREAT WARNING RECEIVER SYSTEM. MUST BE

  11. (HEL MRI) 3D Meta Optics for High Energy Lasers

    DTIC Science & Technology

    2016-09-13

    DISTRIBUTION A: Distribution approved for public release 2 Archival Publications Generated under this MRI Grant: 1. Morgan , Kaitlyn, Keith Miller...Miller, Kaitlyn Morgan , Matthew Byrd, Sean Osler, Robert Ragusa, Wenzhe Li, Brandon M. Cochenour, and Eric G. Johnson. "Multi- gigabit/s underwater...State Lasers, pp. ATu2A-45. Optical Society of America, 2015. 17. A. Brown, A. Ogloza, L. Taylor, J. Thomas , and J. Talghader, “Continuous wave laser

  12. Optically Pumped Far Infrared Molecular Lasers.

    DTIC Science & Technology

    1980-04-01

    third and fifth order nonlinear processes can exceed first order laser processes. An experimental study of the generation of a 22.653 GHz signal (the...prime, practical sources. There are no counterparts in the far infrared of devices like IMPATTs, magnetrons, laser diodes, gyrotrons , etc. While in...1,000 GHz , the only proven, high spectral quality, modest technology, coherent source available to all researchers in the area, is the opti- cally

  13. Application and the key technology on high power fiber-optic laser in laser weapon

    NASA Astrophysics Data System (ADS)

    Qu, Zhou; Li, Qiushi; Meng, Haihong; Sui, Xin; Zhang, Hongtao; Zhai, Xuhua

    2014-12-01

    The soft-killing laser weapon plays an important role in photoelectric defense technology. It can be used for photoelectric detection, search, blinding of photoelectric sensor and other devices on fire control and guidance devices, therefore it draws more and more attentions by many scholars. High power fiber-optic laser has many virtues such as small volume, simple structure, nimble handling, high efficiency, qualified light beam, easy thermal management, leading to blinding. Consequently, it may be used as the key device of soft-killing laser weapon. The present study introduced the development of high power fiber-optic laser and its main features. Meanwhile the key technology of large mode area (LMA) optical fiber design, the beam combination technology, double-clad fiber technology and pumping optical coupling technology was stated. The present study is aimed to design high doping LMA fiber, ensure single mode output by increasing core diameter and decrease NA. By means of reducing the spontaneous emission particle absorbed by fiber core and Increasing the power density in the optical fiber, the threshold power of nonlinear effect can increase, and the power of single fiber will be improved. Meantime, high power will be obtained by the beam combination technology. Application prospect of high power fiber laser in photoelectric defense technology was also set forth. Lastly, the present study explored the advantages of high power fiber laser in photoelectric defense technology.

  14. Monolithic arrays of grating-surface-emitting diode lasers and quantum well modulators for optical communications

    NASA Technical Reports Server (NTRS)

    Carlson, N. W.; Evans, G. A.; Liew, S. K.; Kaiser, C. J.

    1990-01-01

    The electro-optic switching properties of injection-coupled coherent 2-D grating-surface-emitting laser arrays with multiple gain sections and quantum well active layers are discussed and demonstrated. Within such an array of injection-coupled grating-surface-emitting lasers, a single gain section can be operated as intra-cavity saturable loss element that can modulate the output of the entire array. Experimental results demonstrate efficient sub-nanosecond switching of high power grading-surface-emitting laser arrays by using only one gain section as an intra-cavity loss modulator.

  15. Optical isolation in the LIGO gravitational wave laser detector in transient states

    SciTech Connect

    Soloviev, A A; Khazanov, Efim A

    2012-04-30

    This paper presents a numerical analysis of the degree of optical isolation of the laser source by the Faraday isolator in transient states of the laser interferometer gravitational wave observatory (LIGO) detector. This system may be in transient states where the power of the light reflected from the detector to the laser source can exceed many times the power of the source. The present results can be used to analyse the need for installing an additional active mechanical isolation of the source and to evaluate its response time.

  16. Tunable semiconductor laser with an acousto-optic filter in an external fibre cavity

    SciTech Connect

    Andreeva, E V; Mamedov, D S; Ruenkov, A A; Shramenko, M V; Magdich, L N; Yakubovich, S D

    2006-04-30

    A tunable semiconductor laser with a laser amplifier based on a double-pass superluminescent diode as an active element and an acousto-optic filter in an external fibre cavity as a selective element is investigated. A continuous spectral tuning is achieved in a band of width 60 nm centered at a wavelength of 845 nm and the 'instant' linewidth below 0.05 nm is obtained. The sweep frequency within the tuning range achieves 200 Hz. The cw power at the output of a single-mode fibre was automatically maintained constant at the level up to 1.5 mW. (lasers and amplifiers)

  17. Gas laser for efficient sustaining a continuous optical discharge plasma in scientific and technological applications

    SciTech Connect

    Zimakov, V P; Kuznetsov, V A; Kedrov, A Yu; Solov'ev, N G; Shemyakin, A N; Yakimov, M Yu

    2009-09-30

    A stable high-power laser is developed for the study and technical applications of a continuous optical discharge (COD). The laser based on the technology of a combined discharge in a scheme with a fast axial gas flow emits 2.2 kW at 10.6 {mu}m per meter of the active medium in continuous and repetitively pulsed regimes with the electrooptical efficiency 20%. The sustaining of the COD plasma in argon and air is demonstrated at the atmospheric pressure. The emission properties of the COD plasma are studied and its possible applications are discussed. (lasers)

  18. Ultra-high sensitive and high resolution optical coherence tomography using a laser induced electromagnetic dipole

    NASA Astrophysics Data System (ADS)

    Kuroda, Hiroto; Baba, Motoyoshi; Suzuki, Masayuki; Yoneya, Shin

    2013-09-01

    Utilizing an optical coherence tomography measurement, we have developed a technique that actively uses a dielectric response due to an induced dipole moment caused by a mode-locked pulsed laser light source. Irradiated laser light in the material induces a photo-induced electric dipole resulting in a refractive index change for its strong electric field. Using this technique, we obtained a highly sensitive fundus retina tomogram of a human eye in vivo with a resolution of 1.3 μm by single scanning for 20 ms using 8 fs mode-locked pulse laser light with a 350 nm spread spectrum.

  19. Adaptive optics for ultra short pulsed lasers in UHV environment

    NASA Astrophysics Data System (ADS)

    Deneuville, Francois; Ropert, Laurent; Sauvageot, Paul; Theis, Sébastien

    2015-02-01

    ISP SYSTEM has developed an electro-mechanical deformable mirror compatible with Ultra High Vacuum environment, suitable for ultra short pulsed lasers. The design of the MD-AME deformable mirror is based on force application on numerous locations. μ-AME actuators are driven by stepper motors, and their patented special design allows controlling the force with a very high accuracy. Materials and assembly method have been adapted to UHV constraints and the performances were evaluated on a first application for a beam with a diameter of 250mm. A Strehl ratio above 0.9 was reached for this application. Optical aberrations up to Zernike order 5 can be corrected with a very low residual error as for standard MD-AME mirror. Amplitude can reach up to several hundreds of μm for low order corrections. Hysteresis is lower than 0.1% and linearity better than 99%. Contrary to piezo-electric actuators, the μ-AME actuators avoid print-through effects and they permit to keep the mirror shape stable even unpowered, providing a high resistance to electro-magnetic pulses. The deformable mirror design allows changing easily an actuator or even the membrane if needed, in order to improve the facility availability. They are designed for circular, square or elliptical aperture from 30mm up to 500mm or more, with incidence angle from 0° to 45°. They can be equipped with passive or active cooling for high power lasers with high repetition rate.

  20. Adaptive optics scanning laser ophthalmoscope for stabilized retinal imaging

    PubMed Central

    Hammer, Daniel X.; Ferguson, R. Daniel; Bigelow, Chad E.; Iftimia, Nicusor V.; Ustun, Teoman E.; Burns, Stephen A.

    2010-01-01

    A retinal imaging instrument that integrates adaptive optics (AO), scanning laser ophthalmoscopy (SLO), and retinal tracking components was built and tested. The system uses a Hartmann-Shack wave-front sensor (HS-WS) and MEMS-based deformable mirror (DM) for AO-correction of high-resolution, confocal SLO images. The system includes a wide-field line-scanning laser ophthalmoscope for easy orientation of the high-magnification SLO raster. The AO system corrected ocular aberrations to <0.1 μm RMS wave-front error. An active retinal tracking with custom processing board sensed and corrected eye motion with a bandwidth exceeding 1 kHz. We demonstrate tracking accuracy down to 6 μm RMS for some subjects (typically performance: 10–15 μm RMS). The system has the potential to become an important tool to clinicians and researchers for vision studies and the early detection and treatment of retinal diseases. PMID:19516480

  1. Intramural Comparison of NIST Laser and Optical Fiber Power Calibrations.

    PubMed

    Lehman, John H; Vayshenker, Igor; Livigni, David J; Hadler, Joshua

    2004-01-01

    The responsivity of two optical detectors was determined by the method of direct substitution in four different NIST measurement facilities. The measurements were intended to demonstrate the determination of absolute responsivity as provided by NIST calibration services at laser and optical-communication wavelengths; nominally 633 nm, 850 nm, 1060 nm, 1310 nm, and 1550 nm. The optical detectors have been designated as checks standards for the purpose of routine intramural comparison of our calibration services and to meet requirements of the NIST quality system, based on ISO 17025. The check standards are two optical-trap detectors, one based on silicon and the other on indium gallium arsenide photodiodes. The four measurement services are based on: (1) the laser optimized cryogenic radiometer (LOCR) and free field collimated laser light; (2) the C-series isoperibol calorimeter and free-field collimated laser light; (3) the electrically calibrated pyroelectric radiometer and fiber-coupled laser light; (4) the pyroelectric wedge trap detector, which measures light from a lamp source and monochromator. The results indicate that the responsivity of the check standards, as determined independently using the four services, agree to within the published expanded uncertainty ranging from approximately 0.02 % to 1.24 %.

  2. Airborne molecular contamination: quality criterion for laser and optical components

    NASA Astrophysics Data System (ADS)

    Otto, Michael

    2015-02-01

    Airborne molecular contaminations (AMCs) have been recognized as a major problem in semiconductor fabrication. Enormous technical and financial efforts are made to remove or at least reduce these contaminations in production environments to increase yield and process stability. It can be shown that AMCs from various sources in laser devices have a negative impact on quality and lifetime of lasers and optical systems. Outgassing of organic compounds, especially condensable compounds were identified as the main source for deterioration of optics. These compounds can lead to hazing on surfaces of optics, degradation of coating, reducing the signal transmission or the laser signal itself and can enhance the probability of laser failure and damage. Sources of organic outgassing can be molding materials, resins, seals, circuit boards, cable insulation, coatings, paints and others. Critical compounds are siloxanes, aromatic amines and high boiling aromatic hydrocarbons like phthalates which are used as softeners in plastic materials. Nowadays all sensitive assembly steps are performed in controlled cleanroom environments to reduce risks of contamination. We will demonstrate a high efficient air filter concept to remove AMCs for production environments with special AMC filters and methods for the qualification and monitoring of these environments. Additionally, we show modern techniques and examples for the pre-qualification of materials. For assembled components, we provide sampling concepts for a routine measurement for process, component and product qualification. A careful selection of previously tested and certified materials and components is essential to guarantee the quality of lasers and optical devices.

  3. Optical design of a laser system for nuclear fusion research.

    PubMed

    de Metz, J

    1971-07-01

    High power laser improvements, high quality aspheric lenses, and sharp focusing on a solid deuterium target enable us to get numerous nuclear fusion reactions inside the deuterium plasma. Since Maiman successfully built the first light amplifier in 1960 [Nature 187, 493 (1960)] and Terhune performed air breakdown experiments in 1962 ["Optical Third Harmonic Generation," Comptes rendus de la 3ème Conférence Internationale d'Electronique Quantique, Paris, 11-15 février 1963, P. Grivet and N. Bloembergen, Eds. (Dunod, Paris, 1964), pp. 1559-15761, the laser has been thought of as a valuable energy source for fusion devices. Now a kind of race has started toward high temperature plasmas created by powerful lasers. However, the peak power of solid state laser is limited by glass damage, pump efficiences, and unwanted effects such as superradiance. So it is necessary to improve all the optical properties of the laser and the focusing of the lens on the target. In this paper, requirements for fusion implying a very high flux will be stated. Successive optical designs will be described together with measurement methods, and the contribution of optical improvements to the occurrence of nuclear fusion reaction in deuterium targets will be evaluated.

  4. Skin optical clearing for improvement of laser tattoo removal

    NASA Astrophysics Data System (ADS)

    Genina, Elina A.; Bashkatov, Alexey N.; Gavrilova, Anna A.; Pravdin, Alexander B.; Tuchin, Valery V.; Yaroslavsky, Ilya V.; Altshuler, Gregory B.

    2007-06-01

    The removal of tattoo pigments by laser energy is effected through a process of selective photothermolysis. Dehydration and optical immersion based on refractive index matching of scattering centers with that of surrounding matter through introduction of an exogenous index-matching agent can improve laser tattoo removal by providing increased efficiency of laser delivery to embedded ink particles and enabling the use of shorter wavelength visible lasers more effective on certain inks. Effectiveness of a method of accelerating penetration of the index-matching compounds by enhancing skin permeability through creating a lattice of micro-zones of limited thermal damage in the stratum corneum was studied. As optical clearing agents 100% and 88%-aqueous glycerol solutions were used. The effect of stratum corneum perforation on the rate of the immersion clearing of skin was studied. Dynamics of refractive index alteration of glycerol solution during its interaction with skin samples was monitored. Improvement of tattoo visualization was observed. The results of the experiments have shown that the lattice of island damage method the is effective for transepidermal delivery of optical clearing agents and could be used successfully in in vivo conditions for the enhancement of optical clearing of treated skin area and as enabling improvement of laser tattoo removal.

  5. Laser and Optical Subsystem for NASA's Cold Atom Laboratory

    NASA Astrophysics Data System (ADS)

    Kohel, James; Kellogg, James; Elliott, Ethan; Krutzik, Markus; Aveline, David; Thompson, Robert

    2016-05-01

    We describe the design and validation of the laser and optics subsystem for NASA's Cold Atom Laboratory (CAL), a multi-user facility being developed at NASA's Jet Propulsion Laboratory for studies of ultra-cold quantum gases in the microgravity environment of the International Space Station. Ultra-cold atoms will be generated in CAL by employing a combination of laser cooling techniques and evaporative cooling in a microchip-based magnetic trap. Laser cooling and absorption imaging detection of bosonic mixtures of 87 Rb and 39 K or 41 K will be accomplished using a high-power (up to 500 mW ex-fiber), frequency-agile dual wavelength (767 nm and 780 nm) laser and optical subsystem. The CAL laser and optical subsystem also includes the capability to generate high-power multi-frequency optical pulses at 784.87 nm to realize a dual-species Bragg atom interferometer. Currently at Humboldt-Universität zu Berlin.

  6. Optical properties of femtosecond laser-treated diamond

    NASA Astrophysics Data System (ADS)

    Calvani, P.; Bellucci, A.; Girolami, M.; Orlando, S.; Valentini, V.; Lettino, A.; Trucchi, D. M.

    2014-10-01

    A laser-induced periodic surface structure (LIPSS) has been fabricated on polycrystalline diamond by an ultrashort Ti:Sapphire pulsed laser source ( λ = 800 nm, P = 3 mJ, 100 fs) in a high vacuum chamber (<10-7 mbar) in order to increase diamond absorption in the visible and infrared wavelength ranges. A horizontally polarized laser beam had been focussed perpendicularly to the diamond surface and diamond target had been moved by an automated X- Y translational stage along the two directions orthogonal to the optical axis. Scanning electron microscopy of samples reveals an LIPSS with a ripple period of about 170 nm, shorter than the laser wavelength. Raman spectra of processed sample do not point out any evident sp 2 content, and diamond peak presents a right shift, indicating a compressive stress. The investigation of optical properties of fs-laser surface textured diamond is reported. Spectral photometry in the range 200/2,000 nm wavelength shows a significant increase of visible and infrared absorption (more than 80 %) compared to untreated specimens (less than 40 %). The analysis of optical characterization data highlights a close relationship between fabricated LIPSS and absorption properties, confirming the optical effectiveness of such a treatment as a light-trapping structure for diamond: these properties, reported for the first time, open the path for new applications of CVD diamond.

  7. Deep ultraviolet laser micromachining of novel fibre optic devices

    NASA Astrophysics Data System (ADS)

    Li, J.; Dou, J.; Herman, P. R.; Fricke-Begemann, T.; Ihlemann, J.; Marowsky, G.

    2007-04-01

    A deep ultraviolet F2 laser, with output at 157-nm wavelength, has been adopted for micro-shaping the end facets of single and multi-mode silica optical fibres. The high energy 7.9-eV photons drive strong interactions in the wide-bandgap silica fibres to enable the fabrication of surface-relief microstructures with high spatial resolution and smooth surface morphology. Diffraction gratings, focusing lenses, and Mach-Zehnder interferometric structures have been micromachined onto the cleaved-fibre facets and optically characterized. F2-laser micromachining is shown to be a rapid and facile means for direct-writing of novel infibre photonic components.

  8. Ultrafast Optics: Vector Cavity Fiber Lasers - Physics and Technology

    DTIC Science & Technology

    2016-06-14

    AFRL-AFOSR-JP-TR-2016-0065 Ultrafast Optics - Vector Cavity Lasers: Physics and Technology Dingyuan Tang NANYANG TECHNOLOGICAL UNIVERSITY Final... Physics and Technology 5a.  CONTRACT NUMBER 5b.  GRANT NUMBER FA2386-13-1-4096 5c.  PROGRAM ELEMENT NUMBER 61102F 6.  AUTHOR(S) Dingyuan Tang 5d...AOARD Grant FA2386-13-1-4096 “Ultrafast Optics: Vector Cavity Fiber Lasers - Physics and Technology” Name of Principal Investigator: A/Prof. Tang

  9. Ultrafast Optics - Vector Cavity Lasers: Physics and Technology

    DTIC Science & Technology

    2016-06-14

    AFRL-AFOSR-JP-TR-2016-0065 Ultrafast Optics - Vector Cavity Lasers: Physics and Technology Dingyuan Tang NANYANG TECHNOLOGICAL UNIVERSITY Final... Physics and Technology 5a.  CONTRACT NUMBER 5b.  GRANT NUMBER FA2386-13-1-4096 5c.  PROGRAM ELEMENT NUMBER 61102F 6.  AUTHOR(S) Dingyuan Tang 5d...AOARD Grant FA2386-13-1-4096 “Ultrafast Optics: Vector Cavity Fiber Lasers - Physics and Technology” Name of Principal Investigator: A/Prof. Tang

  10. Sensitivity of quantum-dot semiconductor lasers to optical feedback.

    PubMed

    O'Brien, D; Hegarty, S P; Huyet, G; Uskov, A V

    2004-05-15

    The sensitivity of quantum-dot semiconductor lasers to optical feedback is analyzed with a Lang-Kobayashi approach applied to a standard quantum-dot laser model. The carriers are injected into a quantum well and are captured by, or escape from, the quantum dots through either carrier-carrier or phonon-carrier interaction. Because of Pauli blocking, the capture rate into the dots depends on the carrier occupancy level in the dots. Here we show that different carrier capture dynamics lead to a strong modification of the damping of the relaxation oscillations. Regions of increased damping display reduced sensitivity to optical feedback even for a relatively large alpha factor.

  11. DFB laser based electrical dynamic interrogation for optical fiber sensors

    NASA Astrophysics Data System (ADS)

    Carvalho, J. P.; Frazão, O.; Baptista, J. M.; Santos, J. L.; Barbero, A. P.

    2012-04-01

    An electrical dynamic interrogation technique previously reported by the authors for long-period grating sensors is now progressed by relying its operation exclusively on the modulation of a DFB Laser. The analysis of the detected first and second harmonic generated by the electrical modulation of the DFB Laser allows generating an optical signal proportional to the LPG spectral shift and resilient to optical power fluctuations along the system. This concept permits attenuating the effect of the 1/f noise of the photodetection, amplification and processing electronics on the sensing head resolution. This technique is employed in a multiplexing sensing scheme that measures refractive index variations.

  12. Chemical bond activation observed with an x-ray laser

    DOE PAGES

    Beye, Martin; Öberg, Henrik; Xin, Hongliang; ...

    2016-09-01

    The concept of bonding and anti-bonding orbitals is fundamental in chemistry. The population of those orbitals and the energetic difference between the two reflect the strength of the bonding interaction. Weakening the bond is expected to reduce this energetic splitting, but the transient character of bond-activation has so far prohibited direct experimental access. Lastly, we apply time-resolved soft X-ray spectroscopy at a free-electron laser to directly observe the decreased bonding–anti-bonding splitting following bond-activation using an ultra short optical laser pulse.

  13. Chemical Bond Activation Observed with an X-ray Laser.

    PubMed

    Beye, Martin; Öberg, Henrik; Xin, Hongliang; Dakovski, Georgi L; Dell'Angela, Martina; Föhlisch, Alexander; Gladh, Jörgen; Hantschmann, Markus; Hieke, Florian; Kaya, Sarp; Kühn, Danilo; LaRue, Jerry; Mercurio, Giuseppe; Minitti, Michael P; Mitra, Ankush; Moeller, Stefan P; Ng, May Ling; Nilsson, Anders; Nordlund, Dennis; Nørskov, Jens; Öström, Henrik; Ogasawara, Hirohito; Persson, Mats; Schlotter, William F; Sellberg, Jonas A; Wolf, Martin; Abild-Pedersen, Frank; Pettersson, Lars G M; Wurth, Wilfried

    2016-09-15

    The concept of bonding and antibonding orbitals is fundamental in chemistry. The population of those orbitals and the energetic difference between the two reflect the strength of the bonding interaction. Weakening the bond is expected to reduce this energetic splitting, but the transient character of bond-activation has so far prohibited direct experimental access. Here we apply time-resolved soft X-ray spectroscopy at a free-electron laser to directly observe the decreased bonding-antibonding splitting following bond-activation using an ultrashort optical laser pulse.

  14. Optical Studies of Active Comets

    NASA Technical Reports Server (NTRS)

    Jewitt, David

    1998-01-01

    This grant was to support optical studies of comets close enough to the sun to be outgassing. The main focus of the observations was drawn to the two extraordinarily bright comets Hyakutake and Hale-Bopp, but other active comets were also studied in detail during the period of funding. Major findings (all fully published) under this grant include: (1) Combined optical and submillimeter observations of the comet/Centaur P/Schwassmann-Wachmann 1 were used to study the nature of mass loss from this object. The submillimeter observations show directly that the optically prominent dust coma is ejected by the sublimation of carbon monoxide. Simultaneous optical-submillimeter observations allowed us to test earlier determinations of the dust mass loss rate. (2) We modelled the rotation of cometary nuclei using time-resolved images of dust jets as the primary constraint. (3) We obtained broad-band optical images of several comets for which we subsequently attempted submillimeter observations, in order to test and update the cometary ephemerides. (4) Broad-band continuum images of a set of weakly active comets and, apparently, inactive asteroids were obtained in BVRI using the University of Hawaii 2.2-m telescope. These images were taken in support of a program to test the paradigm that many near-Earth asteroids might be dead or dormant comets. We measured coma vs. nucleus colors in active comets (finding that coma particle scattering is different from, and cannot be simply related to, nucleus color). We obtained spectroscopic observations of weakly active comets and other small bodies using the HIRES spectrograph on the Keck 10-m telescope. These observation place sensitive limits to outgassing from these bodies, aided by the high (40,000) spectral resolution of HIRES.

  15. Laser ablation plasmas for diagnostics of structured electronic and optical materials during or after laser processing

    NASA Astrophysics Data System (ADS)

    Russo, Richard E.; Bol'shakov, Alexander A.; Yoo, Jong H.; González, Jhanis J.

    2012-03-01

    Laser induced plasma can be used for rapid optical diagnostics of electronic, optical, electro-optical, electromechanical and other structures. Plasma monitoring and diagnostics can be realized during laser processing in real time by means of measuring optical emission that originates from the pulsed laser-material interaction. In post-process applications, e.g., quality assurance and quality control, surface raster scanning and depth profiling can be realized with high spatial resolution (~10 nm in depth and ~3 μm lateral). Commercial instruments based on laser induced breakdown spectrometry (LIBS) are available for these purposes. Since only a laser beam comes in direct contact with the sample, such diagnostics are sterile and non-disruptive, and can be performed at a distance, e.g. through a window. The technique enables rapid micro-localized chemical analysis without a need for sample preparation, dissolution or evacuation of samples, thus it is particularly beneficial in fabrication of thin films and structures, such as electronic, photovoltaic and electro-optical devices or circuits of devices. Spectrum acquisition from a single laser shot provides detection limits for metal traces of ~10 μg/g, which can be further improved by accumulating signal from multiple laser pulses. LIBS detection limit for Br in polyethylene is 90 μg/g using 50-shot spectral accumulation (halogen detection is a requirement for semiconductor package materials). Three to four orders of magnitude lower detection limits can be obtained with a femtosecond laser ablation - inductively coupled plasma mass spectrometer (LA-ICP-MS), which is also provided on commercial basis. Laser repetition rate is currently up to 20 Hz in LIBS instruments and up to 100 kHz in LA-ICP-MS.

  16. Diode Laser Optically Injected by Resonance of a Monolithic Cavity

    NASA Astrophysics Data System (ADS)

    Peng, Yu; Zhao, Yang; Li, Ye; Yang, Tao; Cao, Jian-Ping; Fang, Zhan-Jun; Zang, Er-Jun

    2011-11-01

    We demonstrate a self-injection locking extended cavity diode laser (ECDL) using resonant optical feedback from the p-polarization of a monolithic folded Fabry—Perot parallel cavity (MFC). The full width at half maximum of the MFC resonance is 31 MHz. With the help of a narrow-linewidth reference laser, the linewidth of the ECDL is measured to be about 7 kHz. The frequency of the laser could be tuned at 160 MHz with an amplitude of 40 V by a PZT mounted on the monolithic cavity and the voltage tuning coefficient is about 4 MHz/V.

  17. Spontaneously excited pulses in an optically driven semiconductor laser.

    PubMed

    Wieczorek, Sebastian; Lenstra, Daan

    2004-01-01

    In optically injected semiconductor lasers, intrinsic quantum noise alone, namely, the spontaneous emission and the shot noise, are capable of exciting intensity multipulses from a steady state operation. Noisy lasers exhibit self-pulsations in the locking region of the corresponding deterministic system. The interpulse time statistics are studied in parameter regions near k-homoclinic (Shilnikov) bifurcations where the corresponding deterministic model exhibits single-, double-, and triple-pulse excitability. These statistics differ significantly among each other, and they could be used to characterize regions of different multipulse excitability in a real laser device.

  18. Quantum dot diode lasers for optical communication systems

    SciTech Connect

    Zhukov, A E; Kovsh, A R

    2008-05-31

    Basic technological and physical aspects of injection lasers based on arrays of self-organised InAs/InGaAs quantum dots on GaAs substrates for optical communication systems in the 1.2-1.3 {mu}m spectral range are considered. The possibility of simultaneous lasing at a great number of longitudinal modes at a high power level and low noise is demonstrated. The use of these lasers in wavelength-division-multiplexing systems based on the spectral separation of the laser output spectrum is substantiated. (invited paper)

  19. Inter-satellite communications using laser based optical links

    NASA Astrophysics Data System (ADS)

    Panahi, Allen S.; Kazemi, Alex A.

    2007-09-01

    Laser Communications offer a viable alternative to established RF communications for inter-satellite links and other applications where high performance links are a necessity. High data rate, small antenna size, narrow beam divergence, and a narrow field of view are characteristics of laser communications that offer a number of potential advantages for system design. This paper will focus on the requirements of the lasers and optics used for beam forming, as well as receiver antenna gain and detectors used in free space communications. Also discussed are the critical parameters in the Transmitter, Channel, Receiver, and link budget that are employed in successful inter-satellite communications system.

  20. Medical Applications Of CO2 Laser Fiber Optics

    NASA Astrophysics Data System (ADS)

    McCord, R. C.

    1981-07-01

    In 1978, Hughes Laboratories reported development of fiber optics that were capable of transmitting CO2 laser energy. These fibers are now being tested for medical applications. Wide ranging medical investigation with CO2 lasers has occurred during the twelve years since the first observations of laser hemostasis. Specialists in ophthalmology, neurosurgery, urology, gynecology, otolaryngology, maxillo-facial/plastic surgery, dermatology, and oncology among others, have explored its use. In principle, all these specialists use CO2 laser radiation at 10.6 microns to thermally destroy diseased tissues. As such, CO2 lasers compare and compete with electrosurgical devices. The fundamental difference between these modalities lies in how they generate heat in treated tissue.

  1. TOPICAL REVIEW: Optically pumped nanowire lasers: invited review

    NASA Astrophysics Data System (ADS)

    Zimmler, Mariano A.; Capasso, Federico; Müller, Sven; Ronning, Carsten

    2010-02-01

    This paper reviews several topics related to optically pumped ZnO nanowire lasers. A systematic study of the various properties of a device as it evolves from the regime of amplified spontaneous emission to laser oscillation above threshold is presented. The key dependence of the laser threshold on nanowire diameter is demonstrated and explained by means of a thorough study of guided modes in semiconducting nanowires for a nanowire-on-substrate geometry. A 'head on' detection geometry is used to measure the far-field profile of a nanowire laser and thus identify the modes responsible for lasing. Finally, the temperature behavior of a nanowire laser is reported, and possible mechanisms that may be responsible for gain are suggested.

  2. Replicated diffractive optical lens components for laser-diode-to-fiber coupling in optical bench arrangements

    NASA Astrophysics Data System (ADS)

    Soechtig, Juergen; Schift, Helmut; Patterson, Bruce D.; Westenhoefer, S.

    1997-09-01

    We report on the fabrication of lens components, based on diffractive optical elements, for the purpose of imaging laser-diode emission onto fibers or photodetectors, or for collimation applications. The miniature optical elements are arranged in arrays with 250 micrometer pitch which make them well suited for applications with fiber ribbons. Test optical plates were made of polycarbonate using hot stamper replication technology. The imaging properties of these optical plates from single-mode fibers onto single-mode fibers or from lasers onto single-mode fibers are discussed. The addition of 3D-marker structures to the outline borders of such plates made them suitable for use in micro-optical benches with built-in mechanical registration structures. We fabricated the optical bench inserts with built-in passive alignment elements using deep x-ray LIGA technology (LIGA is a German acronym for 'lithographie, galvanik und abformung' meaning lithography, electroforming and molding). This technology offers high mechanical precision even for the 500 micrometer thick optical bench inserts which we fabricated by injection molding out of transparent and thermally stable polycarbonate. We report on first arrangements of plastic optical bench inserts into micro-optical benches. With the aim towards a fully replicated micro-optical bench made out of plastic we also report on a mounting concept for laser-didoes with built-in alignment trenches. The fabrication process and important properties of these special lasers which we recently developed for transceiver applications are described. We use these lasers for imaging onto single-mode fibers applying the diffractive optical element plates already mentioned.

  3. Binary arithmetic using optical symbolic substitution and integrated phototransistor surface-emitting laser logic.

    PubMed

    Cheng, J; Olbright, G R; Bryan, R P

    1991-10-20

    We outline an architecture for performing binary addition by using optical symbolic substitution and optical logic gates based on heterojunctionphototransistors and verticalcavity surface-emitting lasers.

  4. Multiple Isotope Magneto Optical Trap from a single diode laser

    NASA Astrophysics Data System (ADS)

    Gomez, Eduardo; Valenzuela, Victor; Hamzeloui, Saeed; Gutierrez, Monica

    2013-05-01

    We present a simple design for a Dual Isotope Magneto Optical Trap. The system requires a single diode laser, a fiber modulator and a tapered amplifier to trap and completely control both 85Rb and 87Rb. We generate all the frequencies needed for trapping both species using the fiber intensity modulator. All the frequencies are amplified simultaneously with the tapered amplifier. The position and power of each frequency is now controlled independently on the RF rather than on the optical side. This introduces an enormous simplification for laser cooling that often requires an acousto-optic modulator for each frequency. The range of frequency changes is much bigger than what is available with acousto-optic modulators since in our case is determined by the modulator bandwidth (10 GHz). Additional isotopes can be simply added by including additional RF frequencies to the modulator and extra beams for other uses can be produced the same way. Support from CONACYT, PROMEP and UASLP.

  5. Optical tweezers based on near infrared diode laser

    NASA Astrophysics Data System (ADS)

    Grego, S.; Arimondo, Ennio; Frediani, Carlo

    1997-07-01

    Emission from a single-mode 100 mW diode laser at 840 nm is used to create optical tweezers: the trapping laser beam is introduced into a microscope and focused by the objective. The microscope also allows monitoring of the motion of the trapped particles. The optical tweezers were monitored with objectives having different numerical apertures between 0.65 and 1.3. The optical trapping of polystyrene spheres with a radius between 0.11 and 7.45 micrometers and of biological objects, the flagellated alga Tetraselmis, with typical dimensions of 8 X 8 X 13 micrometers 3 were studied. The efficiency of the optical tweezers has been characterized through a parameter Q and compared with theoretical models.

  6. Selection and amplification of a single optical frequency comb mode for laser cooling of the strontium atoms in an optical clock

    SciTech Connect

    Liu, Hui; Yin, Mojuan; Kong, Dehuan; Xu, Qinfang; Zhang, Shougang; Chang, Hong

    2015-10-12

    In this paper, we report on the active filtering and amplification of a single mode from an optical femtosecond laser comb with mode spacing of 250 MHz by optical injection of two external-cavity diode lasers operating in cascade to build a narrow linewidth laser for laser cooling of the strontium atoms in an optical lattice clock. Despite the low injection of individual comb mode of approximately 50 nW, a single comb line at 689 nm could be filtered and amplified to reach as high as 10 mW with 37 dB side mode suppression and a linewidth of 240 Hz. This method could be applied over a broad spectral band to build narrow linewidth lasers for various applications.

  7. Acousto-optic modulation in diode pumped solid state lasers

    NASA Astrophysics Data System (ADS)

    Jabczynski, Jan K.; Zendzian, Waldemar; Kwiatkowski, Jacek

    2007-02-01

    The main properties of acousto-optic modulators (AOM) applied in laser technology are presented and discussed in the paper. The critical review of application of AOMs in several types of diode pumped solid state lasers (DPSSL) is given. The short description of few DPSSLs developed in our group is presented in the following chapters of the paper. The parameters of a simple AO-Q-switched Nd:YVO 4 laser (peak power up to 60 kW, pulse duration of 5-15 ns, repetition rate in the range 10-100 kHz, with average power above 5 W) are satisfactory for different application as follows: higher harmonic generation, pumping of 'eye-safe' OPOs etc. The achieved brightness of 10 17 W/m2/srd is comparable to the strongest technological Q-switched lasers of kW class of average power. The main aim of paper is to present novel type of lasers with acousto-optic modulation namely: AO-q-switched and mode locked (AO-QML) lasers. We have designed the 3.69-m long Z-type resonator of the frequency matched to the RF frequency of AOM. As a gain medium the Nd:YVO 4 crystal end pumped by 20 W laser diode was applied. The energy of envelope of QML pulse train was up to 130 μJ with sub-nanosecond mode locked pulse of maximum 30-μJ energy.

  8. Laser spot detection and characteristic analysis in space optical communication

    NASA Astrophysics Data System (ADS)

    Duan, Jin; Kong, Chuiliu; Jing, Wenbo; Zhang, Dan; Jiang, Huilin

    2007-11-01

    In the space laser communication, the link of communication is builded in atmospheric random channel. the laser transmission is affected by the atmospheric turbulence seriously. The communication laser is modulated to circular polarized light in order to reduce the influence of the atmospheric turbulence. A several experiments are designed to validate that the circular polarized laser is available to reduce the communication noise in the space optical communication. The methods of the laser spot detection and spot parameter analysis is put forward in this paper: Firstly the subtraction of the background is used in image preprocessing in order to eliminate the influence of static background, then a series of methods such as the local dynamic threshold segmentation, edge extraction are used to detect and recognize the spot. Finally the parameters of the spot are calculated such as spot's average brightness, background's average brightness and the contrast gradient, and the characteristic of the laser communication is analyzed. The experiment results show that the circular polarized laser can enhance the contrast and improve the communication quality in the spatial optical communication. This method satisfies the request of real-time processing in communication, and is also effective and practical. practical.

  9. Optical cell cleaning with NIR femtosecond laser pulses

    NASA Astrophysics Data System (ADS)

    Uchugonova, Aisada; Breunig, Hans Georg; Batista, Ana; König, Karsten

    2015-03-01

    Femtosecond laser microscopes have been used as both micro and nanosurgery tools. The optical knock-out of undesired cells in multiplex cell clusters shall be further reported on in this study. Femtosecond laser-induced cell death is beneficial due to the reduced collateral side effects and therefore can be used to selectively destroy target cells within monolayers, as well as within 3D tissues, all the while preserving cells of interest. This is an important characteristic for the application in stem cell research and cancer treatment. Non-precise damage compromises the viability of neighboring cells by inducing side effects such as stress to the cells surrounding the target due to the changes in the microenvironment, resulting from both the laser and laser-exposed cells. In this study, optimum laser parameters for optical cleaning by isolating single cells and cell colonies are exploited through the use of automated software control. Physiological equilibrium and cellular responses to the laser induced damages are also investigated. Cell death dependence on laser focus, determination and selectivity of intensity/dosage, controllable damage and cell recovery mechanisms are discussed.

  10. Laser Card For Compact Optical Data Storage Systems

    NASA Astrophysics Data System (ADS)

    Drexler, Jerome

    1982-05-01

    The principal thrust of the optical data storage industry to date has been the 10 billion bit optical disc system. Mass memory has been the primary objective. Another objective that is beginning to demand recognition is compact memory of 1 million to 40 million bits--on a wallet-size, laser recordable card. Drexler Technology has addressed this opportunity and has succeeded in demonstrating laser writing and readback using a 16 mm by 85 mm recording stripe mounted on a card. The write/read apparatus was developed by SRI International. With this unit, 5 micron holes have been recorded using a 10 milliwatt, 830 nanometer semiconductor-diode laser. Data is entered on an Apple II keyboard using the ASCII code. The recorded reflective surface is scanned with the same laser at lower power to generate a reflected bit stream which is converted into alphanumerics and which appear on the monitor. We are pleased to report that the combination of the DREXONTM laser recordable card ("Laser Card"), the semiconductor-diode laser, arrays of large recorded holes, and human interactive data rates are all mutually compatible and point the way forward to economically feasible, compact, data-storage systems.

  11. High Speed 1.55 μm Lasers for Fiber Optic Transmission

    NASA Astrophysics Data System (ADS)

    Morton, Paul A.

    This paper describes the essential elements for creating a practical wide bandwidth directly modulated laser source. This includes considerations of the intrinsic limitations of the laser structure, due to the resonant frequency and damping of the laser output, together with carrier transport issues to allow carriers in the device active region to be efficiently modulated at high speeds. The use of a P-doped compressively strained multiple-quantum well active region to provide high intrinsic speed and remove transport limitations is described, together with record setting results of 25 GHz modulation bandwidth for a 1.55 μm Fabry-Perot laser and 26 GHz bandwidth for a 1.55 μm DFB laser. The challenges of providing high bandwidth electrical connections to the laser on a suitable submount, together with fiber attachment and microwave packaging are discussed. Results of fully packaged 1.55 μm DFB lasers with 25 GHz modulation bandwidth are shown. Digital modulation of the packaged 1.55 μm DFB including impedance matching is described, and the transient wavelength chirp is presented. This low chirp is reduced further using an optical filter, to provide a 10 GBit/s source that can transmit error free over 38.5 km of standard optical fiber.

  12. Novel fiber optic tip designs and devices for laser surgery

    NASA Astrophysics Data System (ADS)

    Hutchens, Thomas Clifton

    Fiber optic delivery of laser energy has been used for years in various types of surgical procedures in the human body. Optical energy provides several benefits over electrical or mechanical surgery, including the ability to selectively target specific tissue types while preserving others. Specialty fiber optic tips have also been introduced to further customize delivery of laser energy to the tissue. Recent evolution in lasers and miniaturization has opened up opportunities for many novel surgical techniques. Currently, ophthalmic surgeons use relatively invasive mechanical tools to dissect retinal deposits which occur in proliferative diabetic retinopathy. By using the tight focusing properties of microspheres combined with the short optical penetration depth of the Erbium:YAG laser and mid-IR fiber delivery, a precise laser scalpel can be constructed as an alternative, less invasive and more precise approach to this surgery. Chains of microspheres may allow for a self limiting ablation depth of approximately 10 microm based on the defocusing of paraxial rays. The microsphere laser scalpel may also be integrated with other surgical instruments to reduce the total number of handpieces for the surgeon. In current clinical laser lithotripsy procedures, poor input coupling of the Holmium:YAG laser energy frequently damages and requires discarding of the optical fiber. However, recent stone ablation studies with the Thulium fiber laser have provided comparable results to the Ho:YAG laser. The improved spatial beam profile of the Thulium fiber laser can also be efficiently coupled into a fiber approximately one third the diameter and reduces the risk of damaging the fiber input. For this reason, the trunk optical fiber minus the distal fiber tip can be preserved between procedures. The distal fiber tip, which degrades during stone ablation, could be made detachable and disposable. A novel, low-profile, twist-locking, detachable distal fiber tip interface was designed

  13. Continued Optical Sensor Operations in a Laser Environment

    DTIC Science & Technology

    2011-02-16

    micro-UAV applications , including non-cooled LWIR sensors . 28 Analysis of Optical Sensor Vulnerability to Lasers In the preceding paragraphs, we...6) Using equations (5) and (6), Table (3) shows the corresponding propagation losses in dB and the resultant power levels at the sensor at...source as indicated The above power levels illustrate the potential vulnerability of optical sensors to

  14. Optical modulation of quantum cascade laser with optimized excitation wavelength.

    PubMed

    Yang, Tao; Chen, Gang; Tian, Chao; Martini, Rainer

    2013-04-15

    The excitation wavelength for all-optical modulation of a 10.6 μm mid-infrared (MIR) quantum cascade laser (QCL) was varied in order to obtain maximum modulation depth. Both amplitude and wavelength modulation experiments were conducted at 820 nm and 1550 nm excitation respectively, whereby the latter matches the interband transition in the QCL active region. Experimental results show that for continuous-wave mode-operated QCL, the efficiency of free carrier generation is doubled under 1550 nm excitation compared with 820 nm excitation, resulting in an increase of the amplitude modulation index from 19% to 36%. At the same time, the maximum wavelength shift is more than doubled from 1.05 nm to 2.80 nm. Furthermore, for the first time to our knowledge, we demonstrated the optical switching of a QCL operated in pulse mode by simple variation of the excitation wavelength.

  15. High density, optically corrected, micro-channel cooled, v-groove monolithic laser diode array

    DOEpatents

    Freitas, Barry L.

    1998-01-01

    An optically corrected, micro-channel cooled, high density laser diode array achieves stacking pitches to 33 bars/cm by mounting laser diodes into V-shaped grooves. This design will deliver>4kW/cm2 of directional pulsed laser power. This optically corrected, micro-channel cooled, high density laser is usable in all solid state laser systems which require efficient, directional, narrow bandwidth, high optical power density pump sources.

  16. High density, optically corrected, micro-channel cooled, v-groove monolithic laser diode array

    DOEpatents

    Freitas, B.L.

    1998-10-27

    An optically corrected, micro-channel cooled, high density laser diode array achieves stacking pitches to 33 bars/cm by mounting laser diodes into V-shaped grooves. This design will deliver > 4kW/cm{sup 2} of directional pulsed laser power. This optically corrected, micro-channel cooled, high density laser is usable in all solid state laser systems which require efficient, directional, narrow bandwidth, high optical power density pump sources. 13 figs.

  17. Beam Modes of Lasers with Misaligned Complex Optical Elements.

    NASA Astrophysics Data System (ADS)

    Tovar, Anthony Alan

    1995-01-01

    A recurring theme in my research is that mathematical matrix methods may be used in a wide variety of physics and engineering applications. Transfer matrix techniques are conceptually and mathematically simple, and they encourage a systems approach. Once one is familiar with one transfer matrix method, it is straightforward to learn another, even if it is from a completely different branch of science. Thus it is useful to overview these methods, and this has been done here. Of special interest are the applications of these methods to laser optics, and matrix theorems concerning multipass optical systems and periodic optical systems have been generalized here to include, for example, the effect of misalignment on the performance of an optical system. In addition, a transfer matrix technique known as generalized beam method has been derived to treat misalignment effects in complex optical systems. Previous theories used numerical or ad hoc analytical solutions to a complicated diffraction integral. The generalized beam matrix formalism was also extended to higher-order beam modes of lasers and used to study mode discrimination in lasers with misaligned complex optical elements.

  18. Compressive sensing optical coherence tomography using randomly accessible lasers

    NASA Astrophysics Data System (ADS)

    Harfouche, Mark; Satyan, Naresh; Vasilyev, Arseny; Yariv, Amnon

    2014-05-01

    We propose and demonstrate a novel a compressive sensing swept source optical coherence tomography (SSOCT) system that enables high speed images to be taken while maintaining the high resolution offered from a large bandwidth sweep. Conventional SSOCT systems sweep the optical frequency of a laser ω(t) to determine the depth of the reflectors at a given lateral location. A scatterer located at delay τ appears as a sinusoid cos (ω(t)τ ) at the photodetector. The finite optical chirp rate and the speed of analog to digital and digital to analog converters limit the acquisition rate of an axial scan. The proposed acquisition modality enables much faster image acquisition rates by interrogating the beat signal at randomly selected optical frequencies while preserving resolution and depth of field. The system utilizes a randomly accessible laser, a modulated grating Y-branch laser, to sample the interference pattern from a scene at randomly selected optical frequencies over an optical bandwidth of 5 THz , corresponding to a resolution of 30 μm in air. The depth profile is then reconstructed using an l1 minimization algorithm with a LASSO constraint. Signal-dependent noise sources, shot noise and phase noise, are analyzed and taken into consideration during the recovery. Redundant dictionaries are used to improve the reconstruction of the depth profile. A compression by a factor of 10 for sparse targets up to a depth of 15 mm in noisy environments is shown.

  19. A Multiterawatt Laser Using a High-Contrast, Optical Parametric Chirped-Pulse Presamplifier

    SciTech Connect

    Bagnoud, V.; Puth, J.; Begishev, I.; Guardalben, M.; Zuegel, J.D.; Forget, N.; LeBlanc, C.

    2005-09-30

    A laser has been built that uses optical parametric chirped-pulse preamplification and a glass booster amplifier. We review the performance of the 5-Hz, multijoule OPCPA pump laser, the 370-mJ OPCPA, and the overall laser.

  20. Hemodynamic responses to functional activation accessed by optical imaging

    NASA Astrophysics Data System (ADS)

    Ni, Songlin; Li, Pengcheng; Yang, Yuanyuan; Lv, Xiaohua; Luo, Qingming

    2006-01-01

    A multi-wavelength light-emitting diode (LED) and laser diode (LD) based optical imaging system was developed to visualize the changes in cerebral blood flow, oxygenation following functional activation simultaneously in rodent cortex. The 2-D blood flow image was accessed by laser speckle contrast imaging, and the spectroscopic imaging of intrinsic signal was used for the calculation of oxyhemoglobin (HbO), deoxyhemoglobin (Hb) and total hemoglobin (HbT) concentration. The combination of spectroscopic imaging and laser speckle contrast imaging provides the capability to simultaneously investigate the spatial and temporal blood flow and hemoglobin concentration changes with high resolution, which may lead to a better understanding of the coupling between neuronal activation and vascular responses. The optical imaging system been built is compact and convenient to investigators. And it is reliable to acquire raw data. In present study, the hemodynamic responses to cortical spreading depression (CSD) in parietal cortex of ~-chloralose/urethan anesthetized rats were demonstrated.

  1. Different ways to active optical frequency standards

    NASA Astrophysics Data System (ADS)

    Pan, Duo; Xue, Xiaobo; Zhang, Xiaogang; Chen, Jingbiao

    2016-06-01

    Active optical frequency standard, or active optical clock, is a new concept of optical frequency standard, where a weak feedback with phase coherence information in optical bad-cavity limitation is formed, and the continuous self-sustained coherent stimulated emission between two atomic transition levels with population inversion is realized. Through ten years of both theoretical and experimental exploration, the narrow linewidth and suppression of cavity pulling effect of active optical frequency standard have been initially proved. In this paper, after a simple review, we will mainly present the most recent experimental progresses of active optical frequency standards in Peking University, including 4-level cesium active optical frequency standards and active Faraday optical frequency standards. The future development of active optical frequency standards is also discussed.

  2. Stable passive optical clock generation in SOA-based fiber lasers.

    PubMed

    Wang, Jing-Yun; Lin, Kuei-Huei; Chen, Hou-Ren

    2015-02-15

    Stable optical pulse trains are obtained from 1.3-μm and 1.5-μm semiconductor optical amplifier (SOA)-based fiber lasers using passive optical technology. The waveforms depend on SOA currents, and the repetition rates can be tuned by varying the relative length of sub-cavities. The output pulse trains of these SOA-based fiber lasers are stable against intracavity polarization adjustment and environmental perturbation. The optical clock generation is explained in terms of mode competition, self-synchronization, and SOA saturation. Without resorting to any active modulation circuits or devices, the technology used here is simple and may find various applications in the future.

  3. Femtosecond Laser Microfabrication of an Integrated Device for Optical Release and Sensing of Bioactive Compounds

    PubMed Central

    Ghezzi, Diego; Vazquez, Rebeca Martinez; Osellame, Roberto; Valtorta, Flavia; Pedrocchi, Alessandra; Valle, Giuseppe Della; Ramponi, Roberta; Ferrigno, Giancarlo; Cerullo, Giulio

    2008-01-01

    Flash photolysis of caged compounds is one of the most powerful approaches to investigate the dynamic response of living cells. Monolithically integrated devices suitable for optical uncaging are in great demand since they greatly simplify the experiments and allow their automation. Here we demonstrate the fabrication of an integrated bio-photonic device for the optical release of caged compounds. Such a device is fabricated using femtosecond laser micromachining of a glass substrate. More in detail, femtosecond lasers are used both to cut the substrate in order to create a pit for cell growth and to inscribe optical waveguides for spatially selective uncaging of the compounds present in the culture medium. The operation of this monolithic bio-photonic device is tested using both free and caged fluorescent compounds to probe its capability of multipoint release and optical sensing. Application of this device to the study of neuronal network activity can be envisaged. PMID:27873888

  4. Optical Design of Adaptive Optics Confocal Scanning Laser Ophthalmoscope with Two Deformable Mirrors.

    PubMed

    Yang, Jinsheng; Wang, Yuanyuan; Rao, Xuejun; Wei, Ling; Li, Xiqi; He, Yi

    2017-01-01

    We describe the optical design of a confocal scanning laser ophthalmoscope with two deformable mirrors. Spherical mirrors are used for pupil relay. Defocus aberration of the human eye is corrected by a Badal focusing structure and astigmatism aberration is corrected by a deformable mirror. The main optical system achieves a diffraction-limited performance through the entire scanning field (6 mm pupil, 3 degrees on pupil plane). The performance of the optical system, with correction of defocus and astigmatism, is also evaluated.

  5. Zigzag laser with reduced optical distortion

    DOEpatents

    Albrecht, G.F.; Comaskey, B.; Sutton, S.B.

    1994-04-19

    The architecture of the present invention has been driven by the need to solve the beam quality problems inherent in Brewster's angle tipped slab lasers. The entrance and exit faces of a solid state slab laser are cut perpendicular with respect to the pump face, thus intrinsically eliminating distortion caused by the unpumped Brewster's angled faces. For a given zigzag angle, the residual distortions inherent in the remaining unpumped or lightly pumped ends may be reduced further by tailoring the pump intensity at these ends. 11 figures.

  6. Zigzag laser with reduced optical distortion

    DOEpatents

    Albrecht, Georg F.; Comaskey, Brian; Sutton, Steven B.

    1994-01-01

    The architecture of the present invention has been driven by the need to solve the beam quality problems inherent in Brewster's angle tipped slab lasers. The entrance and exit faces of a solid state slab laser are cut perpendicular with respect to the pump face, thus intrinsically eliminating distortion caused by the unpumped Brewster's angled faces. For a given zigzag angle, the residual distortions inherent in the remaining unpumped or lightly pumped ends may be reduced further by tailoring the pump intensity at these ends.

  7. Laser Damage in Thin Film Optical Coatings

    DTIC Science & Technology

    1992-07-01

    OTHER RELEVANT ISSUES The damage thresholds of refractory oxides used as AR coatings for alexandrite laser rods were determined and measured by...used and a limited number of TiO 2/SiO2 coatings were put on alexandrite substrates. Single layer AR coatings of MgF2 and NaAIF 6 were also tested for...measurements were made using an alexandrite laser at a wavelength of 790 nm. with a pulse duration of 200 nsec at 30Hz for 2 seconds. The near spot

  8. Catadioptric optics for laser Doppler velocimeter applications

    NASA Technical Reports Server (NTRS)

    Dunagan, Stephen E.

    1989-01-01

    This paper examines the adaptation of low-cost Schmidt-Cassegrain astronomical telescopes to perform the laser-beam-focusing and scattered-light collection tasks associated with dual-beam laser Doppler velocimetry. A generic telescope design is analyzed using ray-tracing methods and Gaussian beam-propagation theory. A straightforward modification procedure to convert from infinite to near unity conjugate-ratio operation with very low residual aberration is identified and tested with a 200-mm-aperture telescope modified for f/10 operation. Performance data for this modified telescope configuration are near the diffraction limit and agree well with predictions.

  9. Catadioptric optics for laser Doppler velocimeter applications

    NASA Technical Reports Server (NTRS)

    Dunagan, Stephen E.

    1989-01-01

    This paper examines the adaptation of low-cost Schmidt-Cassegrain astronomical telescopes to perform the laser-beam-focusing and scattered-light collection tasks associated with dual-beam laser Doppler velocimetry. A generic telescope design is analyzed using ray-tracing methods and Gaussian beam-propagation theory. A straightforward modification procedure to convert from infinite to near unity conjugate-ratio operation with very low residual aberration is identified and tested with a 200-mm-aperture telescope modified for f/10 operation. Performance data for this modified telescope configuration are near the diffraction limit and agree well with predictions.

  10. Use of laser radar imagery in optical pattern recognition: the Optical Processor Enhanced Ladar (OPEL) Program

    NASA Astrophysics Data System (ADS)

    Goldstein, Dennis H.; Mills, Stuart A.; Dydyk, Robert B.

    1998-03-01

    The Optical Processor Enhanced Ladar (OPEL) program is designed to evaluate the capabilities of a seeker obtained by integrating two state-of-the-art technologies, laser radar, or ladar, and optical correlation. The program is a thirty-two month effort to build, optimize, and test a breadboard seeker system (the OPEL System) that incorporates these two promising technologies. Laser radars produce both range and intensity image information. Use of this information in an optical correlator is described. A correlator with binary phase input and ternary amplitude and phase filter capability is assumed. Laser radar imagery was collected on five targets over 360 degrees of azimuth from 3 elevation angles. This imagery was then processed to provide training sets in preparation for filter construction. This paper reviews the ladar and optical correlator technologies used, outlines the OPEL program, and describes the OPEL system.

  11. Transurethral optical-laser knife and probe director for lateral firing laser probes

    NASA Astrophysics Data System (ADS)

    Malek, Reza S.

    1994-02-01

    Laser energy has been used by many for transurethral incision of small, obstructive prostates, vesical neck contractures, and urethral strictures. The customary techniques of moving the tip of the laser fiber through a cystoscope with a conventional laser guide, almost tangentially to the tissue to be incised, or drilling radially arranged holes in the scar, or both, have been cumbersome and imprecise. To provide exact control of the laser fiber and precise delivery of laser energy, a new guide was devised. It conducts the quartz fiber through the sheath and along the lens of an optical urethrotome. The tip of the quartz fiber contacts the tissue at an angle of 20 degree(s). KTP/532 laser energy is used to perform internal urethrotomy for urethral stricture, transurethral incision of postoperative contracture of the vesical neck, and transurethral incision of the small prostate under constant visual control.

  12. Post mortem results of laser-optical system packaged for use in harsh environments

    NASA Astrophysics Data System (ADS)

    Bright, Michelle R.

    2008-08-01

    The design and packaging of laser-optical system was tested to harsh environments outside lab conditions and post mortem activities will be discussed. Previously, custom mounts and bonded optical assemblies were environmentally tested to ensure their survivability. The results verified the sub-assemblies would enable the design of a laser-optical initiation system that could be fielded for use in extreme conditions. The design package, which utilized the proven opto-mechanical sub-assemblies, was then tested to the same levels as the sub-assemblies. The test regiment encompassed the harshest environments currently utilized. Temperature tests were performed ranging from a maximum of +75 degrees C to a minimum of -55 degrees C, allowing for two hour soak at each temperature set point. Vibration tests were performed to a maximum level of 15.5 grms for forty seconds in each of three critical axes. Shock tests were performed to a maximum impulse level of 5700 G's for the sub-assemblies with a 1.1 millisecond long pulse; whereas the packaged laser system maximum level reached was 3700 G's at 1.1 millisecond long pulse. The laser-optical assembly was visually inspected and functionally tested before and after each test to verify survival. As designed, the system covers were laser welded shut for hermetic seal. The only open port was the laser output for testing and verification of laser performance. No optical cables were utilized. Therefore the visual inspection of the interior was performed post mortem. The post mortem results will be discussed as will the potential of redesigns on future packaging strategies.

  13. Post mortem results of laser-optical system packaged for use in harsh environments

    SciTech Connect

    Bright, Michelle R.

    2008-08-28

    In this study, the design and packaging of laser-optical system was tested to harsh environments outside lab conditions and post mortem activities will be discussed. Previously, custom mounts and bonded optical assemblies were environmentally tested to ensure their survivability. The results verified the sub-assemblies would enable the design of a laser-optical initiation system that could be fielded for use in extreme conditions. The design package, which utilized the proven opto-mechanical sub-assemblies, was then tested to the same levels as the sub-assemblies. The test regiment encompassed the harshest environments currently utilized. Temperature tests were performed ranging from a maximum of +75 degrees C to a minimum of -55 degrees C, allowing for two hour soak at each temperature set point. Vibration tests were performed to a maximum level of 15.5 grms for forty seconds in each of three critical axes. Shock tests were performed to a maximum impulse level of 5700 G's for the sub-assemblies with a 1.1 millisecond long pulse; whereas the packaged laser system maximum level reached was 3700 G's at 1.1 millisecond long pulse. The laser-optical assembly was visually inspected and functionally tested before and after each test to verify survival. As designed, the system covers were laser welded shut for hermetic seal. The only open port was the laser output for testing and verification of laser performance. No optical cables were utilized. Therefore the visual inspection of the interior was performed post mortem. Finally, the post mortem results will be discussed as will the potential of redesigns on future packaging strategies.

  14. Exploratory Development on Laser and Optical Materials.

    DTIC Science & Technology

    FIELDS, CERIUM , QUANTUM EFFICIENCY, DOPING, BAND THEORY OF SOLIDS, LUMINESCENCE, ELECTRON TRANSITIONS, ENERGY LEVELS, RARE EARTH ELEMENTS, GADOLINIUM... FLUORIDES , STARK EFFECT, BARIUM COMPOUNDS, MIXERS(ELECTRONICS), STRONTIUM COMPOUNDS, OPTICAL PUMPING, CADMIUM COMPOUNDS, CALCIUM FLUORIDES .

  15. Catastrophic Optical Damage in High-Power, Broad-Area Laser Diodes

    NASA Astrophysics Data System (ADS)

    Chin, Aland K.; Bertaska, Rick K.

    Catastrophic optical damage (COD) is semiconductor material within the optical cavity of laser diodes that is thermally damaged by the laser light. COD results in the failure of laser diodes. The phenomena of COD in high-power, broad-area laser diodes are described along with methods to eliminate it.

  16. Optical booster for dielectric laser accelerators

    NASA Astrophysics Data System (ADS)

    Hanuka, Adi; Cohen, Chen; Lyabock, Haggai; Schächter, Levi

    2017-03-01

    We present a study of adiabatic tapering of a dielectric laser accelerator and the dynamics of the trapping process. The characteristics of the trapped electrons were studied for different initial conditions. Space-charge effects on the longitudinal motion were considered as well.

  17. Laser illuminator and optical system for disk patterning

    DOEpatents

    Hackel, Lloyd A.; Dane, C. Brent; Dixit, Shamasundar N.; Everett, Mathew; Honig, John

    2000-01-01

    Magnetic recording media are textured over areas designated for contact in order to minimize friction with data transducing heads. In fabricating a hard disk, an aluminum nickel-phosphorous substrate is polished to a specular finish. A mechanical means is then used to roughen an annular area intended to be the head contact band. An optical and mechanical system allows thousands of spots to be generated with each laser pulse, allowing the textured pattern to be rapidly generated with a low repetition rate laser and an uncomplicated mechanical system. The system uses a low power laser, a beam expander, a specially designed phase plate, a prism to deflect the beam, a lens to transmit the diffraction pattern to the far field, a mechanical means to rotate the pattern and a trigger system to fire the laser when sections of the pattern are precisely aligned. The system generates an annular segment of the desired pattern with which the total pattern is generated by rotating the optical system about its optic axis, sensing the rotational position and firing the laser as the annular segment rotates into the next appropriate position. This marking system can be integrated into a disk sputtering system for manufacturing magnetic disks, allowing for a very streamlined manufacturing process.

  18. In situ window cleaning by laser blowoff through optical fiber

    SciTech Connect

    Alfier, A.; Pasqualotto, R.; Barison, S.; Pagura, C.; Danieli, T.; Giudicotti, L.

    2008-10-15

    The feasibility of a window cleaning system based on the laser blowoff technique is investigated to remove the impurity deposition on vacuum windows of the modified reversed field experiment fusion device. The laser pulse is sent to the window through a fused silica fiber optic ({phi}=1 mm), then focused on its internal surface, single shot ablating up to {approx}5 mm{sup 2} of the impurity layer; the focused pulse is scanned across the window to clean its entire surface. The composition of the deposited layer is studied through the secondary ion mass spectrometry and profilometry techniques. Effectiveness of cleaning is analyzed in terms of quality of the cleaned spot, its dimension, repetition rate of the laser, and its wavelength. The energy damage threshold of the fiber optic is also investigated. Three different lasers (microjoule Nd:YAG, Nd:YLF, and ruby) are first tested directly on the window; then only the ruby laser beam is propagated through an optical fiber and tested.

  19. In situ window cleaning by laser blowoff through optical fiber.

    PubMed

    Alfier, A; Barison, S; Danieli, T; Giudicotti, L; Pagura, C; Pasqualotto, R

    2008-10-01

    The feasibility of a window cleaning system based on the laser blowoff technique is investigated to remove the impurity deposition on vacuum windows of the modified reversed field experiment fusion device. The laser pulse is sent to the window through a fused silica fiber optic (phi=1 mm), then focused on its internal surface, single shot ablating up to approximately 5 mm(2) of the impurity layer; the focused pulse is scanned across the window to clean its entire surface. The composition of the deposited layer is studied through the secondary ion mass spectrometry and profilometry techniques. Effectiveness of cleaning is analyzed in terms of quality of the cleaned spot, its dimension, repetition rate of the laser, and its wavelength. The energy damage threshold of the fiber optic is also investigated. Three different lasers (microjoule Nd:YAG, Nd:YLF, and ruby) are first tested directly on the window; then only the ruby laser beam is propagated through an optical fiber and tested.

  20. Performance of laser guide star adaptive optics at Lick Observatory

    SciTech Connect

    Olivier, S.S.; An, J.; Avicola, K.

    1995-07-19

    A sodium-layer laser guide star adaptive optics system has been developed at Lawrence Livermore National Laboratory (LLNL) for use on the 3-meter Shane telescope at Lick Observatory. The system is based on a 127-actuator continuous-surface deformable mirror, a Hartmann wavefront sensor equipped with a fast-framing low-noise CCD camera, and a pulsed solid-state-pumped dye laser tuned to the atomic sodium resonance line at 589 nm. The adaptive optics system has been tested on the Shane telescope using natural reference stars yielding up to a factor of 12 increase in image peak intensity and a factor of 6.5 reduction in image full width at half maximum (FWHM). The results are consistent with theoretical expectations. The laser guide star system has been installed and operated on the Shane telescope yielding a beam with 22 W average power at 589 nm. Based on experimental data, this laser should generate an 8th magnitude guide star at this site, and the integrated laser guide star adaptive optics system should produce images with Strehl ratios of 0.4 at 2.2 {mu}m in median seeing and 0.7 at 2.2 {mu}m in good seeing.

  1. Optical superheterodyne receiver uses laser for local oscillator

    NASA Technical Reports Server (NTRS)

    Lucy, R. F.

    1966-01-01

    Optical superheterodyne receiver uses a laser coupled to a frequency translator to supply both the incident signal and local oscillator signal and thus permit reception of amplitude modulated video bandwidth signals through the atmosphere. This receiver is useful in scientific propagation experiments, tracking experiments, and communication experiments.

  2. Resonant optical characteristics of an ultracold laser plasma

    SciTech Connect

    Kosarev, N I; Shaparev, N Ya

    2009-12-31

    We report a computer simulation study of light absorption, scattering and emission at 397 nm in an ultracold calcium ion plasma under resonant excitation. The results point to spectral asymmetry of light scattering, nonlinear absorption, and emission in the plasma. An approach is proposed for ultracold plasma diagnostics using resonant optical characteristics. (laser plasma)

  3. Redistribution of the laser beam power using diffractive optical elements

    NASA Astrophysics Data System (ADS)

    Murzin, Serguei P.; Liedl, Gerhard; Bielak, Robert

    2017-04-01

    The use of laser technologies in the production of optical fiber requires a careful choice of optical systems for positioning and transforming the laser beam. The purpose of this research is to determine a possibility of the redistribution of the laser beam power using diffractive optical elements. It was determined that for a radius of the focusable beam Rf = rf =2.2×10-2 m, the length of the focal spot will be increased to a value L =13.6×10-3 m, which is 1.2 times larger than Rf = rf =1.8×10-2 m. In this case, the intensity of the laser beam at the centre of the focal spot, q0 , and the maximum value, qmax , decreased by 1.1 times. An approximation of function q(x, y) by polynomials of degree n =5and m =3 was performed. It is shown that the maximal relative error of approximation does not exceed 4%, and the relative error of approximation in the centre of the focal spot does not exceed 3%. Presented equations can be used to calculate the intensity distribution in the focal plane of diffractive optical elements.

  4. Laser Electro-Optic Engineering Technology. Florida Vocational Program Guide.

    ERIC Educational Resources Information Center

    University of South Florida, Tampa. Dept. of Adult and Vocational Education.

    This program guide identifies particular considerations in the organization, operation, and evaluation of laser electro-optic engineering technology programs. Contents include an occupational description and information on the following: program content, including a curriculum framework that details major concepts and intended outcomes and a list…

  5. Research on optic antenna of space laser communication networking

    NASA Astrophysics Data System (ADS)

    Meng, Li-Xin; Li, Long; Zhang, Li-zhong; Zhao, Shan-shan; Jiang, Hui-lin

    2013-08-01

    With the highlights of the high transmission rate, large capacity, strong anti-interference and anti-capture ability, good security and small light, space laser communication becomes an important hotspot. At present, the focus of research of the laser communication system is point to point communication structure. However, from the application point of view, both the realization of space laser communication among multiple points and the establishment of the information transmission network can really have the practical value. Aiming at the problem of space laser communication network, this article puts forward the general idea about optical antenna to achieve multiple tracking goals at the same time. Through the analysis of the optical antenna, and the comparing of the current commonly used mirror driving mechanism, a new mirror driving mechanism is designed. The azimuth motion, containing circular grating feedback, is driven by torque motor,voice coil motor of fan produces pitch motion that has fan-shaped grating feedback, so that compression of the structure size to improve the efficiency of the reflector assembly. Through the establishment of the driving mechanism and the kinematic model of 3D entity, the relationship between the single drive azimuth and pitch angle following the angle of incident light is explained. The biggest ideal view area affecting the optical antenna is obtained by the simulation analysis of the kinematics model using MATLAB. The several factors of field overlap area and blind area offers a theoretical basis for structure optimization and control system for the subsequent optical antenna design.

  6. Phase dynamics in a Doppler broadened optically-pumped laser

    NASA Astrophysics Data System (ADS)

    Roldán, E.; de Valcárcel, G. J.; Vilaseca, R.; Silva, F.; Pujol, J.; Corbalán, R.; Laguarta, F.

    1989-11-01

    The dynamic behavior of the phase of the generated field in a Doppler-broadened optically-pumped far-infrared laser is theoretically investigated for the first time. The phase undergoes sudden jumps of approximately π radians, which allow to establish the actual symmetry of the main attractor in the phase space, explaining the heteroclynic character of the chaotic behavior observed in experiments.

  7. Laser Electro-Optic Engineering Technology. Florida Vocational Program Guide.

    ERIC Educational Resources Information Center

    University of South Florida, Tampa. Dept. of Adult and Vocational Education.

    This program guide identifies particular considerations in the organization, operation, and evaluation of laser electro-optic engineering technology programs. Contents include an occupational description and information on the following: program content, including a curriculum framework that details major concepts and intended outcomes and a list…

  8. Toward laser welding of glasses without optical contacting

    NASA Astrophysics Data System (ADS)

    Richter, S.; Zimmermann, F.; Eberhardt, R.; Tünnermann, A.; Nolte, S.

    2015-10-01

    The welding of transparent materials with ultrashort laser pulse at high repetition rates has attracted much attention due to its potential applications in fields such as optics, microfluidics, optofluidics and precision machinery. One demanding issue is the stable and reliable welding of different materials without the utilization of an intermediate layer or an optical contact. In this work, we maximized the size of the molten volume in order to generate a large pool of molten material which is able to fill an existing gap between the samples. To this end, we used bursts of ultrashort laser pulses with an individual pulse energy of up to . The laser-induced welding seams exhibit a base area with a size of up to . Using these large modifications, we are able to overcome the requirement of an optical contact and weld even gaps with a height of about . Bulging of the sample surface and ejection of molten material in the gap between the two samples allow to bridge the gap and enable successful welding. We also determined the breaking strength of laser-welded fused silica samples without an optical contact by a three-point bending test. The determined value of up to 73 MPa is equivalent to 85 % of stability of the pristine bulk material.

  9. Laser beacon adaptive optics for power beaming applications

    SciTech Connect

    Fugate, R.Q.

    1994-12-31

    This paper discusses the laser beam control system requirements for power beaming applications. Power beaming applications include electric and thermal engine propulsion for orbit transfer, station changing, and recharging batteries. Beam control includes satellite acquisition, high accuracy tracking, higher order atmospheric compensation using adaptive optics, and precision point-ahead. Beam control may also include local laser beam clean-up with a low order adaptive optics system. This paper also presents results of tracking and higher-order correction experiments on astronomical objects. The results were obtained with a laser beacon adaptive optics system at Phillips Laboratory`s Starfire Optical Range near Albuquerque, NM. At a wavelength of 0.85 {mu}m, the author has achieved Strehl ratios of {approximately}0.50 using laser beacons and {approximately}0.65 using natural stars for exposures longer than one minute on objects of {approximately}8{sup th} magnitude. The resulting point spread function has a full width half maximum (FWHM) of 0.13 arcsec.

  10. Quantum mechanical features of optically pumped CW FIR lasers

    NASA Technical Reports Server (NTRS)

    Seligson, D.; Leite, J. R. R.; Sanchez, A.; Feld, M. S.; Ducloy, M.

    1977-01-01

    Quantum mechanical predictions for the gain of an optically pumped CW FIR laser are presented for cases in which one or both of the pump and FIR transitions are pressure or Doppler broadened. The results are compared to those based on the rate equation model. Some of the quantum mechanical predictions are verified in CH3OH.

  11. Optical control of antibacterial activity

    NASA Astrophysics Data System (ADS)

    Velema, Willem A.; van der Berg, Jan Pieter; Hansen, Mickel J.; Szymanski, Wiktor; Driessen, Arnold J. M.; Feringa, Ben L.

    2013-11-01

    Bacterial resistance is a major problem in the modern world, stemming in part from the build-up of antibiotics in the environment. Novel molecular approaches that enable an externally triggered increase in antibiotic activity with high spatiotemporal resolution and auto-inactivation are highly desirable. Here we report a responsive, broad-spectrum, antibacterial agent that can be temporally activated with light, whereupon it auto-inactivates on the scale of hours. The use of such a ‘smart’ antibiotic might prevent the build-up of active antimicrobial material in the environment. Reversible optical control over active drug concentration enables us to obtain pharmacodynamic information. Precisely localized control of activity is achieved, allowing the growth of bacteria to be confined to defined patterns, which has potential for the development of treatments that avoid interference with the endogenous microbial population in other parts of the organism.

  12. Test Port for Fiber-Optic-Coupled Laser Altimeter

    NASA Technical Reports Server (NTRS)

    Ramos Izquierdo, Luis; Scott, V. Stanley; Rinis, Haris; Cavanaugh, John

    2011-01-01

    A test port designed as part of a fiber optic coupled laser altimeter receiver optical system allows for the back-illumination of the optical system for alignment verification, as well as illumination of the detector(s) for testing the receiver electronics and signal-processing algorithms. Measuring the optical alignment of a laser altimeter instrument is difficult after the instrument is fully assembled. The addition of a test port in the receiver aft-optics allows for the back-illumination of the receiver system such that its focal setting and boresight alignment can be easily verified. For a multiple-detector receiver system, the addition of the aft-optics test port offers the added advantage of being able to simultaneously test all the detectors with different signals that simulate the expected operational conditions. On a laser altimeter instrument (see figure), the aft-optics couple the light from the receiver telescope to the receiver detector(s). Incorporating a beam splitter in the aft-optics design allows for the addition of a test port to back-illuminate the receiver telescope and/or detectors. The aft-optics layout resembles a T with the detector on one leg, the receiver telescope input port on the second leg, and the test port on the third leg. The use of a custom beam splitter with 99-percent reflection, 1-percent transmission, and a mirrored roof can send the test port light to the receiver telescope leg as well as the detector leg, without unduly sacrificing the signal from the receiver telescope to the detector. The ability to test the receiver system alignment, as well as multiple detectors with different signals without the need to disassemble the instrument or connect and reconnect components, is a great advantage to the aft-optics test port. Another benefit is that the receiver telescope aperture is fully back-illuminated by the test port so the receiver telescope focal setting vs. pressure and or temperature can be accurately measured (as

  13. Optical glucose monitoring using vertical cavity surface emitting lasers (VCSELs)

    NASA Astrophysics Data System (ADS)

    Talebi Fard, Sahba; Hofmann, Werner; Talebi Fard, Pouria; Kwok, Ezra; Amann, Markus-Christian; Chrostowski, Lukas

    2009-08-01

    Diabetes Mellitus is a common chronic disease that has become a public health issue. Continuous glucose monitoring improves patient health by stabilizing the glucose levels. Optical methods are one of the painless and promising methods that can be used for blood glucose predictions. However, having accuracies lower than what is acceptable clinically has been a major concern. Using lasers along with multivariate techniques such as Partial Least Square (PLS) can improve glucose predictions. This research involves investigations for developing a novel optical system for accurate glucose predictions, which leads to the development of a small, low power, implantable optical sensor for diabetes patients.

  14. Holograms for laser diode: Single mode optical fiber coupling

    NASA Technical Reports Server (NTRS)

    Fuhr, P. L.

    1982-01-01

    The low coupling efficiency of semiconductor laser emissions into a single mode optical fibers place a severe restriction on their use. Associated with these conventional optical coupling techniques are stringent alignment sensitivities. Using holographic elements, the coupling efficiency may be increased and the alignment sensitivity greatly reduced. Both conventional and computer methods used in the generation of the holographic couplers are described and diagrammed. The reconstruction geometries used are shown to be somewhat restrictive but substantially less rigid than their conventional optical counterparts. Single and double hologram techniques are examined concerning their respective ease of fabrication and relative merits.

  15. Femtosecond Laser Processing by Using Patterned Vector Optical Fields

    PubMed Central

    Lou, Kai; Qian, Sheng-Xia; Ren, Zhi-Cheng; Tu, Chenghou; Li, Yongnan; Wang, Hui-Tian

    2013-01-01

    We present and demonstrate an approach for femtosecond laser processing by using patterned vector optical fields (PVOFs) composed of multiple individual vector optical fields. The PVOFs can be flexibly engineered due to the diversity of individual vector optical fields in spatial arrangement and distribution of states of polarization, and it is easily created with the aid of a spatial light modulator. The focused PVOFs will certainly result in various interference patterns, which are then used to fabricate multi-microholes with various patterns on silicon. The present approach can be expanded to fabricate three-dimensional microstructures based on two-photon polymerization. PMID:23884360

  16. Q-switched Nd:YAG optical vortex lasers.

    PubMed

    Kim, D J; Kim, J W; Clarkson, W A

    2013-12-02

    Q-switched operation of a high-quality Nd:YAG optical vortex laser with the first order Laguerre-Gaussian mode and well-determined helical wavefronts using a fiber-based pump beam conditioning scheme is reported. A simple two-mirror resonator incorporating an acousto-optic Q-switch was employed, along with an etalon and a Brewster plate to enforce the particular helicity of the output. The laser yielded Q-switched pulses with ~250 μJ pulse energy and ~33 ns pulse duration (FWHM) at a 0.1 kHz repetition rate for 5.1 W of absorbed pump power. The handedness of the helical wavefronts was preserved regardless of the repetition rates. The prospects of further power scaling and improved laser performance are discussed.

  17. Integrated all-optical infrared switchable plasmonic quantum cascade laser.

    PubMed

    Kohoutek, John; Bonakdar, Alireza; Gelfand, Ryan; Dey, Dibyendu; Nia, Iman Hassani; Fathipour, Vala; Memis, Omer Gokalp; Mohseni, Hooman

    2012-05-09

    We report a type of infrared switchable plasmonic quantum cascade laser, in which far field light in the midwave infrared (MWIR, 6.1 μm) is modulated by a near field interaction of light in the telecommunications wavelength (1.55 μm). To achieve this all-optical switch, we used cross-polarized bowtie antennas and a centrally located germanium nanoslab. The bowtie antenna squeezes the short wavelength light into the gap region, where the germanium is placed. The perturbation of refractive index of the germanium due to the free carrier absorption produced by short wavelength light changes the optical response of the antenna and the entire laser intensity at 6.1 μm significantly. This device shows a viable method to modulate the far field of a laser through a near field interaction.

  18. Two-laser optical tweezers with a blinking beam

    NASA Astrophysics Data System (ADS)

    Lamperska, Weronika; Masajada, Jan; Drobczyński, Sławomir; Gusin, Paweł

    2017-07-01

    We report on a two-laser holographic optical tweezers setup and present its two major advantages over single-laser one. First, the trap stiffness of a weak trapping beam can be measured with a considerable accuracy. Second, a novel method of examining local viscosity of fluid is proposed. Both measurements are performed based on forcing the oscillations of a microscopic polystyrene bead placed between two optical traps. The two beams are generated by separate laser sources and therefore their trapping power can vary. Moreover, a stronger trap 'blinks', modulated by an electronic shutter. The blinking frequency can be precisely adjusted to the experimental conditions, which results in high accuracy of the measurements.

  19. Optical monitoring of high power direct diode laser cladding

    NASA Astrophysics Data System (ADS)

    Liu, Shuang; Farahmand, Parisa; Kovacevic, Radovan

    2014-12-01

    Laser cladding is one of the most advanced surface modification techniques which can be used to build and repair high-value components. High power direct diode laser (HPDDL) offers unique quality and cost advantages over other lasers (CO2, Nd:YAG). Especially its rectangular laser beam with top-hat intensity distribution makes HPDDL an ideal tool for large area cladding. In order to utilize this technique successfully, the development of on-line monitoring and process control is necessary. In this study, an optical monitoring system consisting of a high-speed CCD camera, a pyrometer, and an infrared camera was used to analyze the mass- and heat-transfer in the cladding process. The particle transport in flight was viewed by a high-speed CCD camera; the interaction between powder flow and laser beam was observed by an infrared camera; and the thermal behavior of the molten pool was recorded by the pyrometer and the infrared camera. The effects of the processing parameters on the laser attenuation, particle heating and clad properties were investigated based on the obtained signals. The optical monitoring method improved the understanding about mutual interrelated phenomena in the cladding process.

  20. Laser speckle imaging of atherosclerotic plaques through optical fiber bundles

    PubMed Central

    Nadkarni, Seemantini K.; Bouma, Brett E.; Yelin, Dvir; Gulati, Amneet; Tearney, Guillermo J.

    2009-01-01

    Laser speckle imaging (LSI), a new technique that measures an index of plaque viscoelasticity, has been investigated recently to characterize atherosclerotic plaques. These prior studies demonstrated the diagnostic potential of LSI for detecting high-risk plaques and were conducted ex vivo. To conduct intracoronary LSI in vivo, the laser speckle pattern must be transmitted from the coronary wall to the image detector in the presence of cardiac motion. Small-diameter, flexible optical fiber bundles, similar to those used in coronary angioscopy, may be incorporated into an intravascular catheter for this purpose. A key challenge is that laser speckle is influenced by inter-fiber leakage of light, which may be exacerbated during bundle motion. In this study, we tested the capability of optical fiber bundles to transmit laser speckle patterns obtained from atherosclerotic plaques and evaluated the influence of motion on the diagnostic accuracy of fiber bundle-based LSI. Time-varying helium-neon laser speckle images of aortic plaques were obtained while cyclically moving the flexible length of the bundle to mimic coronary motion. Our results show that leached fiber bundles may reliably transmit laser speckle images in the presence of cardiac motion, providing a viable option to conduct intracoronary LSI. PMID:19021396

  1. ACTIVE MEDIA. LASERS: Diode-array-pumped repetitively pulsed neodymium phosphate glass laser

    NASA Astrophysics Data System (ADS)

    Bogatov, A. P.; Drakin, A. E.; Miftakhutdinov, D. R.; Mikaelyan, G. T.; Starodub, A. N.

    2008-09-01

    Repetitively pulsed generation (200 μs, 40 Hz) was obtained in a neodymium phosphate glass laser pumped by a 870-nm diode array. The maximum slope lasing efficiency with respect to the optical pump energy equal to 13% is restricted by the factor (≈0.23) of active-medium filling by the mode field. By adjusting the laser cavity, the single-transverse mode regime, in particular, the generation of the TEM00 mode is obtained in the entire range of pump energies.

  2. Tetravalent chromium (Cr(4+)) as laser-active ion for tunable solid-state lasers

    NASA Technical Reports Server (NTRS)

    Seas, A.; Petricevic, V.; Alfano, Robert R.

    1992-01-01

    Generation of femtosecond pulses from a continuous-wave mode-locked chromium-doped forsterite (Cr(4+):Mg2SiO4) laser has been accomplished. The forsterite laser was actively mode-locked using an acousto-optic modulator operating at 78 MHz with two Brewster high-dispersion glass prisms for intra-cavity chirp compensation. Transform-limited sub-100-fs pulses were routinely generated in the TEM(sub 00) mode with 85 mW of continuous power (with 1 percent output coupler), tunable over 1230-1280 nm. The shortest pulses of 60-fs pulsewidth were measured.

  3. Horizontal path laser communications employing MEMS adaptive optics correction

    NASA Astrophysics Data System (ADS)

    Thompson, Charles A.; Wilks, Scott C.; Brase, James M.; Young, Richard A.; Johnson, Gary W.; Ruggiero, Anthony J.

    2002-02-01

    Horizontal path laser communications are beginning to provide attractive alternatives for high-speed optical communications. In particular, companies are beginning to sell fiberless alternatives for intranet and sporting event video. These applications are primarily aimed at short distance applications (on the order of 1 km pathlength). There exists a potential need to extend this pathlength to distances much greater than a 1km. For cases of long distance optical propagation, atmospheric turbulence will ultimately limit the maximum achievable data rate. In this paper, we propose a method of improved signal quality through the use of adaptive optics. In particular, we show work in progress toward a high-speed, small footprint Adaptive Optics system for horizontal path laser communications. Such a system relies heavily on recent progress in Micro-Electro-Mechanical Systems (MEMS) deformable mirrors as well as improved communication and computational components. In this paper we detail two Adaptive Optics approaches for improved through-put, the first is the compensated receiver (the traditional Adaptive Optics approach), the second is the compensated transmitter/receiver. The second approach allows for correction of the optical wavefront before transmission from the transmitter and prior to detection at the receiver.

  4. Horizontal Path Laser Communications Employing MEMS Adaptive Optics Correction

    SciTech Connect

    Thompson, C A; Wilks, S C; Brase, J M; Young, R A; Johnson, G W; Ruggiero, A J

    2001-09-05

    Horizontal path laser communications are beginning to provide attractive alternatives for high-speed optical communications, In particular, companies are beginning to sell fiberless alternatives for intranet and sporting event video. These applications are primarily aimed at short distance applications (on the order of 1 km pathlength). There exists a potential need to extend this pathlength to distances much greater than a 1km. For cases of long distance optical propagation, atmospheric turbulence will ultimately limit the maximum achievable data rate. In this paper, we propose a method of improved signal quality through the use of adaptive optics. In particular, we show work in progress toward a high-speed, small footprint Adaptive Optics system for horizontal path laser communications. Such a system relies heavily on recent progress in Micro-Electro-Mechanical Systems (MEMS) deformable mirrors as well as improved communication and computational components. In this paper we detail two Adaptive Optics approaches for improved through-put, the first is the compensated receiver (the traditional Adaptive Optics approach), the second is the compensated transmitter/receiver. The second approach allows for correction of the optical wavefront before transmission from the transmitter and prior to detection at the receiver.

  5. 1300 nm optically pumped quantum dot spin vertical external-cavity surface-emitting laser

    NASA Astrophysics Data System (ADS)

    Alharthi, S. S.; Orchard, J.; Clarke, E.; Henning, I. D.; Adams, M. J.

    2015-10-01

    We report a room temperature optically pumped Quantum Dot-based Spin-Vertical-External-Cavity Surface-Emitting laser (QD Spin-VECSEL) operating at the telecom wavelength of 1.3 μm. The active medium was composed of 5 × 3 QD layers; each threefold group was positioned at an antinode of the standing wave of the optical field. Circularly polarized lasing in the QD-VECSEL under Continuous-Wave optical pumping has been realized with a threshold pump power of 11 mW. We further demonstrate at room temperature control of the QD-VECSEL output polarization ellipticity via the pump polarization.

  6. Fundamental studies on laser radiation therapy: dispersion of a laser beam passing through optical fibres

    NASA Astrophysics Data System (ADS)

    Takahara, H.; Koshijima, T.; Iida, H.

    1986-04-01

    For laser internal therapy in medical applications, optical fibres are required to propagate the laser beam. The far-field pattern of the laser beam at the exit face of the optical fibre is studied using a multimode step-index fibre and a graded index Selfoc fibre. The degree of dispersion, or the output angular distribution, of the beam passing through the Selfoc fibre is much smaller than that passing through the multimode step-index fibre. Consequently, the energy density in the far-field pattern of the beam passing through the Selfoc fibre is very much larger than that for the beam passing through the multimode step-index fibre. It is concluded that the Selfoc fibre is more effective in laser internal therapy.

  7. Monitoring changes of optical attenuation coefficients of acupuncture points during laser acupuncture by optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Huang, Yimei; Yang, Hongqin; Wang, Yuhua; Zheng, Liqin; Xie, Shusen

    2010-11-01

    The physical properties of acupuncture point were important to discover the mechanism of acupuncture meridian. In this paper, we used an optical coherence tomography to monitor in vivo the changes of optical attenuation coefficients of Hegu acupuncture point and non-acupuncture point during laser irradiation on Yangxi acupuncture point. The optical attenuation coefficients of Hegu acupuncture point and non-acupuncture point were obtained by fitting the raw data according to the Beer-Lambert's law. The experimental results showed that the optical attenuation coefficient of Hegu acupuncture point decreased during the laser acupuncture, in contrast to a barely changed result in that of non-acupuncture point. The significant change of optical attenuation coefficient of Hegu acupuncture point indicated that there was a correlation between Hegu and Yangxi acupuncture points to some extent.

  8. Device For Trapping Laser Pulses In An Optical Delay Line

    DOEpatents

    Yu, David U. L.; Bullock, Donald L.

    1997-12-23

    A device for maintaining a high-energy laser pulse within a recirculating optical delay line for a period time to optimize the interaction of the pulse with an electron beam pulse train comprising closely spaced electron micropulses. The delay line allows a single optical pulse to interact with many of the electron micropulses in a single electron beam macropulse in sequence and for the introduction of additional optical pulses to interact with the micropulses of additional electron beam macropulses. The device comprises a polarization-sensitive beam splitter for admitting an optical pulse to and ejecting it from the delay line according to its polarization state, a Pockels cell to control the polarization of the pulse within the delay line for the purpose of maintaining it within the delay line or ejecting it from the delay line, a pair of focusing mirrors positioned so that a collimated incoming optical pulse is focused by one of them to a focal point where the pulse interacts with the electron beam and then afterwards the pulse is recollimated by the second focusing mirror, and a timing device which synchronizes the introduction of the laser pulse into the optical delay line with the arrival of the electron macropulse at the delay line to ensure the interaction of the laser pulse with a prescribed number of electron micropulses in sequence. In a first embodiment of the invention, the principal optical elements are mounted with their axes collinear. In a second embodiment, all principal optical elements are mounted in the configuration of a ring.

  9. Micromanipulation of sperm by a laser generated optical trap

    SciTech Connect

    Tadir, Y.; Wright, W.H.; Vafa, O.; Ord, T.; Asch, R.H.; Berns, M.W. )

    1989-11-01

    The force generated by the radiation pressure of a low power laser beam induces an optical trap which may be used to manipulate sperm. We studied the effect of the optical trap on sperm motility. A Nd:YAG laser beam was coupled to a conventional microscope and focused into the viewing plane by the objective lens. Sperm were caught in the trap and manipulated by a joy stick controlled motorized stage. After different exposure periods, the velocity and patterns were analysed by a computerized image processor. There were minor changes in sperm velocity when exposed to the trap for 30 seconds or less. A gradual decrease in the mean linear velocity was observed after 45 seconds of exposure. This optical micromanipulator may also be useful for studying the force generated by a single spermatozoa and evaluating the influence of drugs on motility.

  10. High-power laser arrays for optical computing

    NASA Astrophysics Data System (ADS)

    Zucker, Erik P.; Craig, Richard R.; Mehuys, David G.; Nam, Derek W.; Welch, David F.; Scifres, Donald R.

    1991-12-01

    We demonstrate both common electrode and addressable arrays of single mode semiconductor lasers suitable for optical computing and optical data storage. In the common electrode geometry, eight lasers have been fabricated on a single chip which show excellent spectral and power uniformity. Total optical power obtained from this array has been in excess of 1.2 Watts CW. We have also fabricated two and nine element monolithic, individually addressable arrays with emitter spacings between 10 jim and 150 p m. Separately addressed, each element emits in a single spatial mode to greater than 0.1 Watts. For the nine element array, uniformity of better than 1.0 nanometer in wavelength and 1 milliamp in operating current across the array has been obtained. Results on crosstalk and reliability of the arrays are presented.

  11. Amplitude Noise Reduction of Ion Lasers with Optical Feedback

    NASA Technical Reports Server (NTRS)

    Herring, Gregory C.

    2011-01-01

    A reduction in amplitude noise on the output of a multi-mode continuous-wave Ar-ion laser was previously demonstrated when a fraction of the output power was retroreflected back into the laser cavity. This result was reproduced in the present work and a Fabry-Perot etalon was used to monitor the longitudinal mode structure of the laser. A decrease in the number of operating longitudinal cavity modes was observed simultaneously with the introduction of the optical feedback and the onset of the amplitude noise reduction. The noise reduction is a result of a reduced number of lasing modes, resulting in less mode beating and amplitude fluctuations of the laser output power.

  12. Fiber-optic laser sensor for mine detection and verification

    SciTech Connect

    Bohling, Christian; Scheel, Dirk; Hohmann, Konrad; Schade, Wolfgang; Reuter, Matthias; Holl, Gerhard

    2006-06-01

    What we believe to be a new optical approach for the identification of mines and explosives by analyzing the surface materials and not only bulk is developed. A conventional manually operated mine prodder is upgraded by laser-induced breakdown spectroscopy (LIBS). In situ and real-time information of materials that are in front of the prodder are obtained during the demining process in order to optimize the security aspects and the speed of demining. A Cr4+:Nd3+:YAG microchip laser is used as a seed laser for an ytterbium-fiber amplifier to generate high-power laser pulses at 1064 nm with pulse powers up to Ep=1 mJ, a repetition rate of frep.=2-20 kHz and a pulse duration of tp=620 ps. The recorded LIBS signals are analyzed by applying neural networks for the data analysis.

  13. The Lunar Laser OCTL Terminal (LLOT) Optical Systems

    NASA Technical Reports Server (NTRS)

    Roberts, W. Thomas; Wright, Malcolm W.

    2013-01-01

    The Lunar Laser OCTL Terminal is an auxiliary ground station terminal for the Lunar Laser Communication Demonstration (LLCD). The LLOT optical systems exercise modulation and beam divergence control over six 10-watt fiber-based laser transmitters at 1568 nanometers, which act as beacons for pointing of the space-based terminal. The LLOT design transmits these beams from distinct sub-apertures of the F/76 OCTL telescope at divergences ranging from 110 microrad to 40 microrad. LLOT also uses the same telescope aperture to receive the downlink signal at 1550 nanometers from the spacecraft terminal. Characteristics and control of the beacon lasers, methods of establishing and maintaining beam alignment, beam zoom system design, co-registration of the transmitted beams and the receive field of view, transmit/receive isolation, and downlink signal manipulation and control are discussed.

  14. Optical gene transfer by femtosecond laser pulses

    NASA Astrophysics Data System (ADS)

    Konig, Karsten; Riemann, Iris; Tirlapur, Uday K.

    2003-07-01

    Targeted transfection of cells is an important technique for gene therapy and related biomedical applications. We delineate how high-intensity (1012 W/cm2) near-infrared (NIR) 80 MHz nanojoule femtosecond laser pulses can create highly localised membrane perforations within a minute focal volume, enabling non-invasive direct transfection of mammalian cells with DNA. We suspended Chinese hamster ovarian (CHO), rat kangaroo kidney epithelial (PtK2) and rat fibroblast cells in 0.5 ml culture medium in a sterile miniaturized cell chamber (JenLab GmbH, Jena, Germany) containing 0.2 μg plasmid DNA vector pEGFP-N1 (4.7 kb), which codes for green fluorescent protein (GFP). The NIR laser beam was introduced into a femtosecond laser scanning microscope (JenLab GmbH, Jena, Germany; focussed on the edge of the cell membrane of a target cell for 16 ms. The integration and expression efficiency of EGFP were assessed in situ by two-photon fluorescence-lifetime imaging using time-correlated single photon counting. The unique capability to transfer foreign DNA safely and efficiently into specific cell types (including stem cells), circumventing mechanical, electrical or chemical means, will have many applications, such as targeted gene therapy and DNA vaccination.

  15. Silicate-matrix active media for tunable solid-state lasers

    SciTech Connect

    Kuznetsova, Rimma T; Mayer, G V; Manekina, Yu A; Tel'minov, E N; Arabei, S M; Pavich, T A; Solovyov, Konstantin N

    2007-08-31

    The lasing characteristics of solid active media based on laser dyes (rhodamines, coumarin 2, paraterphenyl) doped into silicate bulk matrices and thin films of different compositions are studied upon optical excitation. The lasing efficiency, photostability, and spectral parameters of laser media are investigated as functions of the excitation wavelength and intensity. Variations in these parameters due to the interaction of organic luminophores with a silicate matrix and radiation are discussed. (active media. lasers)

  16. Optical design and active optics methods in astronomy

    NASA Astrophysics Data System (ADS)

    Lemaitre, Gerard R.

    2013-03-01

    Optical designs for astronomy involve implementation of active optics and adaptive optics from X-ray to the infrared. Developments and results of active optics methods for telescopes, spectrographs and coronagraph planet finders are presented. The high accuracy and remarkable smoothness of surfaces generated by active optics methods also allow elaborating new optical design types with high aspheric and/or non-axisymmetric surfaces. Depending on the goal and performance requested for a deformable optical surface analytical investigations are carried out with one of the various facets of elasticity theory: small deformation thin plate theory, large deformation thin plate theory, shallow spherical shell theory, weakly conical shell theory. The resulting thickness distribution and associated bending force boundaries can be refined further with finite element analysis.

  17. Pair annihilation in laser pulses: Optical versus x-ray free-electron laser regimes

    SciTech Connect

    Ilderton, Anton; Johansson, Petter; Marklund, Mattias

    2011-09-15

    We discuss the theory and phenomenology of pair annihilation, within an ultrashort laser pulse, to a single photon. The signature of this process is the unidirectional emission of single photons with a fixed energy. We show that the cross section is significantly larger than for two-photon pair annihilation in vacuum, with x-ray free-electron laser parameters admitting a much clearer signal than optical beams.

  18. High-power optical parametric oscillator based on a high-pulse repetition rate, master Nd : KGW laser

    NASA Astrophysics Data System (ADS)

    Bogdanovich, M. V.; Grigor'ev, A. V.; Lantsov, K. I.; Lepchenkov, K. V.; Ryabtsev, A. G.; Ryabtsev, G. I.; Shchemelev, M. A.; Titovets, V. S.; Agrawal, L.; Bhardwaj, A.

    2017-05-01

    An optical scheme of an optical parametric oscillator with a master laser based on an Nd : KGW active element excited by two orthogonally oriented diode side pump modules is proposed to form radiation pulses with energies above 30 mJ and a repetition rate of 1 - 20 Hz in the eye-safe spectral range of 1.5 - 1.6 μm. The two-module excitation of the active medium makes the distribution of the master laser radiation intensity in the output beam cross section more uniform and provides a reliable operation of the optical parametric oscillator.

  19. Conformal optical elements for correcting wavefront distortions in YAG : Nd{sup 3+} active elements

    SciTech Connect

    Korolkov, V P; Nasyrov, R K; Poleshchuk, A G; Arapov, Yu D; Ivanov, A F

    2013-02-28

    Correction of the wavefront is studied for the light beam passing wide-aperture YAG : Nd3+ single-crystal rods, which are used as active elements in high-power solid-state lasers. A nonideal character of the crystal structure is responsible for the deformation of the wavefront of passing radiation. By using the halftone technology we have developed conformal aberration correctors capable of compensating rod nonuniformities and reducing the laser radiation divergence by an order of magnitude. The results obtained make it possible to employ optically nonuniform active elements in laser constructions. (laser optics 2012)

  20. Optimization of optical nonlinearities in quantum cascade lasers

    NASA Astrophysics Data System (ADS)

    Bai, Jing

    Nonlinearities in quantum cascade lasers (QCL's) have wide applications in wavelength tunability and ultra-short pulse generation. In this thesis, optical nonlinearities in InGaAs/AlInAs-based mid-infrared (MIR) QCL's with quadruple resonant levels are investigated. Design optimization for the second-harmonic generation (SHG) of the device is presented. Performance characteristics associated with the third-order nonlinearities are also analyzed. The design optimization for SHG efficiency is obtained utilizing techniques from supersymmetric quantum mechanics (SUSYQM) with both material-dependent effective mass and band nonparabolicity. Current flow and power output of the structure are analyzed by self-consistently solving rate equations for the carriers and photons. Nonunity pumping efficiency from one period of the QCL to the next is taken into account by including all relevant electron-electron (e-e) and longitudinal (LO) phonon scattering mechanisms between the injector/collector and active regions. Two-photon absorption processes are analyzed for the resonant cascading triple levels designed for enhancing SHG. Both sequential and simultaneous two-photon absorption processes are included in the rate-equation model. The current output characteristics for both the original and optimized structures are analyzed and compared. Stronger resonant tunneling in the optimized structure is manifested by enhanced negative differential resistance. Current-dependent linear optical output power is derived based on the steady-state photon populations in the active region. The second-harmonic (SH) power is derived from the Maxwell equations with the phase mismatch included. Due to stronger coupling between lasing levels, the optimized structure has both higher linear and nonlinear output powers. Phase mismatch effects are significant for both structures leading to a substantial reduction of the linear-to-nonlinear conversion efficiency. The optimized structure can be fabricated