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. Optical pumping of generalized laser active materials.

    PubMed

    Fry, F H

    1967-11-01

    Results are presented of a computer-based study on the rate of excitation in the active cores of two types of optically pumped lasers as a function of a number of parameters of the active core. The absorption bands of the active materials are generated by Lorentzian and Gaussian functions. The excitation rate of the active core is proportional to the width of the absorption band at all depths of penetration. The plots of excitation rate as a function of frequency show curves similar to line reversal spectra and emphasize the importance of excitation some distance from the center of the absorption band in the slab model. In the cylindrical model, this wing pumping is even more important due to focusing. The effect of refractive index on the excitation rate is also described. PMID:20062337

  3. 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. PMID:27304296

  4. 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.

  5. 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.

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

    PubMed

    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

  7. 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

  8. 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.

  9. 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.

  10. 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

  11. 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. PMID:21081995

  12. 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.

  13. Optical power of semiconductor lasers with a low-dimensional active region

    SciTech Connect

    Asryan, Levon V.; Sokolova, Zinaida N.

    2014-01-14

    A comprehensive analytical model for the operating characteristics of semiconductor lasers with a low-dimensional active region is developed. Particular emphasis is given to the effect of capture delay of both electrons and holes from a bulk optical confinement region into a quantum-confined active region and an extended set of rate equations is used. We derive a closed-form expression for the internal quantum efficiency as an explicit function of the injection current and parameters of a laser structure. Due to either electron or hole capture delay, the internal efficiency decreases with increasing injection current above the lasing threshold thus causing sublinearity of the light-current characteristic of a laser.

  14. Optics and lasers

    NASA Technical Reports Server (NTRS)

    1976-01-01

    Report describes twenty-seven optical concepts developed for holographic viewing, spectral transmission, and film camera technology. Articles include developments in laser-Doppler systems, laser beam deflection controls, X-ray photography, and camera components.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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%.

  20. 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.

  1. Optical fiber laser

    SciTech Connect

    Snitzer, E.

    1988-10-25

    This patent describes an optical fiber laser comprising: a gain cavity including a single mode optical fiber of given length and index of refraction and a cladding surrounding the core and having an index of refraction lower than that of the core. The core comprising a host material having incorporated therein a predetermined concentration of just erbium oxide having a fluorescence spectrum with a peak emission line at 1.54 micrometers; filter means optically coupled to each end of the fiber gain cavity for providing feedback in the cavity at the peak emission line of the erbium oxide and for permitting energy to be introduced into the cavity at the absorption band of the erbium oxide in the region of 1.45 to 1.53 micrometers; and a laser diode optically coupled to one end of the core for pumping energy into the end of the gain cavity so that the gain cavity oscillates at just the peak emission line.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. Optically active silica and polymeric materials for microcavity lasers and sensors

    NASA Astrophysics Data System (ADS)

    Armani, A. M.; Deka, N.; Mehrabani, S.; Shi, C.; Maker, A.; Lee, M.; Kovach, A.; Gungor, E.; Kuo, K.; Diep, V.

    2015-03-01

    Silica and silica-doped high quality factor (Q) optical resonators have demonstrated ultra-low threshold lasers based on numerous mechanisms (eg rare earth dopants, Raman). To date, the key focus has been on maintaining a high Q, as that determines the lasing threshold and linewidth. However, equally important criteria are lasing efficiency and wavelength. These parameters are governed by the material, not the cavity Q. Therefore, to fully address this challenge, it is necessary to develop new materials. We have synthesized a suite of silica and polymeric materials with nanoparticle and rare-earth dopants to enable the development of microcavity lasers with emission from the near-IR to the UV. Additionally, the efficiencies and thresholds of many of these devices surpass the previous work. Specifically, the silica sol-gel lasers are co- and tri-doped with metal nanoparticles (eg Ti, Al) and rare-earth materials (eg Yb, Nb, Tm) and are fabricated using conventional micro/nanofabrication methods. The intercalation of the metal in the silica matrix reduces the clustering of the rare-earth ions and reduces the phonon energy of the glass, improving efficiency and overall device performance. Additionally, the silica Raman gain coefficient is enhanced due to the inclusion of the metal nanoparticles, which results in a lower threshold and a higher efficiency silica Raman laser. Finally, we have synthesized several polymer films doped with metal (eg Au, Ag) nanoparticles and deposited them on the surface of our microcavity devices. By pumping on the plasmonic resonant wavelength of the particle, we are able to achieve plasmonic-enhanced upconversion lasing.

  9. 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.

  10. 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).

  11. 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.

  12. 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.

  13. Small acousto-optic modulation for active mode locking in the iodine photodissociation laser and the effect of supplementary saturable absorber

    SciTech Connect

    Kim, Y.S.; Lee, S.S.

    1985-02-01

    Active, passive, and active--passive mode locking of the iodine photodissociation laser are investigated. The peak-to-background ratio (PBR) of the acousto-optically mode-locked pulse is 85% for rf power of 5 W. Passive mode locking using BDN dye gives PBR of 75% and has inferior reproducibility. The active--passive mode locking using the two methods simultaneously is useful for the pressure broadened iodine laser line and gives a PBR of 91%. In this case the rf power required for complete mode locking is calculated to be 7 W which is much less than the required power of 11 W in using active mode locking alone.

  14. 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.

  15. 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.

  16. 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.

  17. Optical nonuniformities in nuclear-pumped cylindrical lasers

    SciTech Connect

    Mat'ev, V Yu; Borovkov, V V; Mel'nikov, S P

    2000-03-31

    The optical nonuniformities, formed as a result of the effect of the inhomogeneous energy deposition by the fission fragments irradiating the laser-active gas from thin uranium-containing layers, were calculated for cylindrical nuclear-pumped gas lasers. The results of the calculations agree with the experiment. (active media. lasers)

  18. 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.

  19. Stabilizing a gaseous optical laser

    NASA Technical Reports Server (NTRS)

    Jauan, A.; Shimoda, K.

    1974-01-01

    Frequency of gaseous optical laser can be stabilized by sinusoidally modulating the geometry of the cavity. Fabry-Perot dielectric mirrors are mounted in two Invar blocks that are connected by four magnetorestrictive bars. Each bar has three coils to sinusoidally modulate system. Ac establishes frequency, and dc the average value; both are supplied to coil from control system.

  20. Bismuth-doped-glass optical fibers--a new active medium for lasers and amplifiers.

    PubMed

    Dvoyrin, V V; Mashinsky, V M; Bulatov, L I; Bufetov, I A; Shubin, A V; Melkumov, M A; Kustov, E F; Dianov, E M; Umnikov, A A; Khopin, V F; Yashkov, M V; Guryanov, A N

    2006-10-15

    Optical fibers with bismuth-doped silicate and germanate glass cores were fabricated by the modified chemical vapor deposition technique (solution and vapor-phase Bi incorporation). The fibers revealed an efficient luminescence with a maximum in the 1050-1200 nm spectral range, FWHM up to 200 nm, and a lifetime of the order of 1 ms. PMID:17001368

  1. 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.

  2. Coupled optical resonance laser locking

    NASA Astrophysics Data System (ADS)

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

    2014-10-01

    We have demonstrated simultaneous laser frequency stabilization of a UV and IR laser, to the same spectroscopic sample, by monitoring only the absorption of the UV laser. For trapping and cooling Yb$^{+}$ ions, a frequency stabilized laser is required at 369.95nm to drive the $^{2}S_{1/2}$ $ \\rightarrow $ $ ^{2}P_{1/2}$ cooling transition. Since the cycle is not closed, a 935.18nm laser is needed to drive the $^{2}D_{3/2}$ $\\rightarrow$ $^{3}D_{[3/2]1/2}$ transition which is followed by rapid decay to the $^{2}S_{1/2}$ state. Our 369nm laser is locked to Yb$^{+}$ ions generated in a hollow cathode discharge lamp using saturated absorption spectroscopy. Without pumping, the metastable $^{2}D_{3/2}$ level is only sparsely populated and direct absorption of 935nm light is difficult to detect. A resonant 369nm laser is able to significantly populate the $^{2}D_{3/2}$ state due to the coupling between the levels. Fast re-pumping to the $^{2}S_{1/2}$ state, by 935nm light, can be detected by observing the change in absorption of the 369nm laser using lock-in detection of the photodiode signal. In this way simultaneous locking of two optical frequencies in very different spectral regimes is accomplished. A rate equation model gives good qualitative agreement with the experimental results. This technique offers improved laser frequency stabilization compared to lasers locked individually to the sample and should be readily applicable to similar ion systems.

  3. Laser beam modeling in optical storage systems

    NASA Technical Reports Server (NTRS)

    Treptau, J. P.; Milster, T. D.; Flagello, D. G.

    1991-01-01

    A computer model has been developed that simulates light propagating through an optical data storage system. A model of a laser beam that originates at a laser diode, propagates through an optical system, interacts with a optical disk, reflects back from the optical disk into the system, and propagates to data and servo detectors is discussed.

  4. Optical scanner. [laser doppler velocimeters

    NASA Technical Reports Server (NTRS)

    Rhodes, D. B. (Inventor)

    1977-01-01

    An optical scanner that sequentially focuses optical energy (light) at selected points in space is described. The essential component is a scanning wheel including several glass windows with each window having a different thickness. Due to this difference in thickness, the displacement of the emerging light from the incident light is different for each window. The scanner transmits optical energy to a point in space while at the same time receiving any optical energy generated at that point and then moves on to the next selected point and repeats this transmit and receive operation. It fills the need for a system that permits a laser velocimeter to rapidly scan across a constantly changing flow field in an aerodynamic test facility.

  5. Compact laser sources for laser designation, ranging and active imaging

    NASA Astrophysics Data System (ADS)

    Goldberg, Lew; Nettleton, John; Schilling, Brad; Trussel, Ward; Hays, Alan

    2007-04-01

    Recent advances in compact solid sate lasers for laser designation, eye-safe range finding and active imaging are described. Wide temperature operation of a compact Nd:YAG laser was achieved by end pumping and the use of multi-λ diode stacks. Such lasers enabled construction of fully operational 4.7 lb laser designator prototypes generating over 50 mJ at 10-20 Hz PRF. Output pulse energy in excess of 100 mJ was demonstrated in a breadboard version of the end-pumped laser. Eye-safe 1.5 μm lasers based on flash-pumped, low PRF, Monoblock lasers have enabled compact STORM laser range finders that have recently been put into production. To achieve higher optical and electrical efficiency needed for higher PRF operation, Monoblock lasers were end-pumped by a laser diode stack. Laser diode end-pumped Monoblock lasers were operated at 10-20 Hz PRF over a wide temperature range (-20 to +50 °C). Compared with bulk compact solid state lasers, fiber lasers are characterized by lower pulse energy, higher PRF's, shorter pulses and higher electrical efficiency. An example of fiber lasers suitable for LIDAR, and atmospheric measurement applications is described. Eye-safe, low intensity diode pumped solid state green warning laser developed for US Army checkpoint and convoy applications is also described.

  6. 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.

  7. 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.

  8. Frequency modulated lasers for interferometric optical gyroscopes.

    PubMed

    Komljenovic, Tin; Tran, Minh A; Belt, Michael; Gundavarapu, Sarat; Blumenthal, Daniel J; Bowers, John E

    2016-04-15

    We study the use of frequency modulated lasers in interferometric optical gyroscopes and show that by exploiting various frequency modulation signals, the laser coherence can be controlled. We show that both angle random walk and bias stability of an interferometric optical gyroscope based on laser sources can be improved with this technique. PMID:27082342

  9. 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.

  10. 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.

  11. 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.

  12. Laser diode array and transmission optics

    NASA Technical Reports Server (NTRS)

    Kwon, Jin H.

    1989-01-01

    Information on laser diode array and transmission optics is given in viewgraph form. Information is given on coherent combining of laser diode arrays, amplification through a laser diode array, the far field pattern of a laser diode transmitter, and beam diameter at receiver vs. transmission distance.

  13. 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.

  14. Optical fiber lasers and amplifiers

    SciTech Connect

    Snitzer, E.; Po, H.; Tumminelli, R.P.; Hakimi, F.

    1989-03-21

    An optical fiber is described, which comprises: a substantially single-mode core having an index of refraction n/sub 1/ comprised of laser material disposed within a multi-mode cladding having an index of refraction n/sub 2/; and a further cladding having an index of refraction n/sub 3/ surrounding the multi-mode cladding with substantially no space between the further cladding and the multi-mode cladding; wherein the single-mode core is disposed at an offset from the geometric center of the multi-mode cladding.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. Fiber-Optic Probe For Laser Velocimetry

    NASA Technical Reports Server (NTRS)

    Lynch, Dana H.; Mcalister, Kenneth W.; Gunter, William D., Jr.

    1992-01-01

    Size and weight of optics reduced considerably. Proposed fiber-optic probe in laser velocimeter smaller (and, therefore, lighter in weight and more maneuverable) than previous probe. Proposed configuration is product of calculations and experiments showing virtual waists serve same purpose. Laser-velocimeter lens brought close to transfer lenses to focus on virtual waists, thereby shortening probe head considerably.

  20. 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…

  1. Introduction to Optics and Lasers in Engineering

    NASA Astrophysics Data System (ADS)

    Laufer, Gabriel

    1996-07-01

    In a very short period of time, lasers have advanced from a mere research interest to an increasingly useful, commercially available tool for material processing, precision measurements, surgery, communication, and entertainment. This book provides the background in theoretical physics necessary to understand the engineering applications of lasers. It summarizes relevant theories of geometrical optics, physical optics, quantum optics, and laser physics while tying them to applications in such areas as fluid mechanics, combustion, surface analysis, material processing, and laser machining. The author clearly and thoroughly explains advanced topics such as laser Doppler velocimetry, laser-induced fluorescence, and holography. The book includes numerous examples and advanced problems that simulate real-world research and encourage independent reading and analysis. The book will benefit researchers and students across all branches of engineering.

  2. Laser-Induced Nuclear Activation Studies

    NASA Astrophysics Data System (ADS)

    Simons, Andrew; Gardner, Matthew; Thompson, Peter; Allwork, Christopher; Rubery, Michael; Clarke, Robert

    2009-10-01

    A series of experimental campaigns, each designed to activated carefully selected materials, have been conducted with high- power short-pulse laser systems. These relatively new CPA laser systems can produce large bursts of X-rays, electrons, protons and other ions. Characterising the nature of these mixed radiation fields is neccessary for both physics experiments and facility safety. Three campaigns, two with the HELEN laser faility at AWE and one with the Vulcan Petawatt laser at the Rutherford Appleton laboratory, were designed to accelerate protons. These protons irradiated secondary activation targets of pure foils and various optical glasses, typically those used in target chamber environments such as those found at NIF, Omega and AWE's Orion laser facility. This talk discusses these experiments and covers the production of laser-produced radiation fields, the selection of activation targets, the interpretation the radioactive decay signals, the current status of the analysis and the future applications of this research.

  3. Electro-optical sensor with automatic suppression of laser dazzling

    NASA Astrophysics Data System (ADS)

    Ritt, G.; Eberle, B.

    2012-10-01

    The progress in laser technology leads to very compact but nevertheless powerful laser sources. In the visible and near infrared spectral region, lasers of any wavelength can be purchased. Especially continuous wave laser sources pose a serious threat to the human eye and electro-optical sensors due to their high proliferation and easy availability. The manifold of wavelengths cannot be encountered 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. An anti-dazzle algorithm comprises the analysis of the laser wavelength and the subsequent activation of the appropriate micromirrors of the DMD.

  4. Tunable excitation of mid-infrared optically pumped semiconductor lasers

    NASA Astrophysics Data System (ADS)

    Olafsen, Linda J.; Kunz, Jeremy; Ongstad, Andrew P.; Kaspi, Ron

    2013-01-01

    While conventional semiconductor lasers employ electrical injection for carrier excitation, optically pumped semiconductor lasers (OPSLs) have demonstrated high output powers and high brightness in the mid-infrared. An important consideration for optically pumped lasers is efficient absorption of the pump beam, which can be achieved through increasing the number of periods in the active region, by placing the active region in a cavity with an optical thickness of twice the pump wavelength between distributed Bragg reflectors (Optical Pumping Injection Cavity), or by periodically inserting the active quantum wells into an InGaAsSb waveguide designed to absorb the pump radiation (Integrated Absorber). A tunable optical pumping technique is utilized by which threshold intensities are minimized and efficiencies are maximized. The near-IR idler output of a Nd:YAG-pumped optical parametric oscillator (10 Hz, ~4 ns) is the tunable optical pumping source in this work. Results are presented for an OPSL with a type-II W active region embedded in an integrated absorber to enhance the absorption of the optical pump beam. Emission wavelengths range from 4.64 μm at 78 K to 4.82 μm at 190 K for optical pump wavelengths ranging from 1930-1950 nm. The effect of wavelength tuning is demonstrated and compared to single wavelength pumping (1940 nm) at a higher duty cycle (20- 30%). Comparisons are also made to other OPSLs, including a discussion of the characteristic temperature and high temperature performance of these devices.

  5. First light : from the ruby laser to nonlinear optics

    NASA Astrophysics Data System (ADS)

    Giordmaine, J. A.

    2010-02-01

    Laser action was first demonstrated by Maiman in a flashlamp-pumped ruby crystal in May of 1960. This talk, based in part on personal recollections, recounts some of the research highlights during the two years that followed - a period of exponential growth in the field of quantum electronics, driven by the newly available, unprecedented coherence, power, and monochomaticity of laser light. Active areas from the beginning were new lasers in HeNe and other gas systems, in host crystals with increasingly effective dopants, and in glass. Modes in open resonators became understood, as did the surprising granularity of laser light An important step was the Q-switch, enabling megawatt lasers and providing a new tool for the study of dielectrics at high optical fields. The field of nonlinear optics opened up with experimental discoveries including optical second harmonic generation, two-photon absorption, phase matching and stimulated Raman scattering. A key to subsequent progress was a comprehensive quantum mechanical theory that provided a general description of nonlinear optical processes. The end of the two-year period covered here coincided with two advances which were to shape the future role of lasers in technology and science: the first semiconductor lasers; and a theoretical description of states of light having truly quantum properties, properties not evident in laser light up to that time. )

  6. Optical Effects on Laser Ablated Polymer Surfaces

    NASA Astrophysics Data System (ADS)

    Prabhu, R. D.; Govinthasamy, R.; Murthy, N. S.

    2006-03-01

    Laser ablation of poly (ethylene terephthalate) and polyimide films were investigated using Excimer-UV laser. SEM analyses indicate the presence of rings for a wide range of ablation parameters (fluence, frequency and number of pulses). It is proposed that the particles present in the plasma plume could cause the incident laser light to diffract, similar to the optical effects observed in the femtosecond laser ablation of solids. The polymer surface provides a perfect medium to register the optical signatures as seen in the SEM images. The fringe-spacings observed in the images are compared with the theoretical diffraction patterns and the height of the plasma particles above the surface is estimated using an optimization scheme. The results of the analysis are consistent with experimentally observed dynamics of the plasma plume. It is proposed that such optical effects could be a routine feature in the laser ablation of polymers. The significance of such artifacts for lithography is discussed.

  7. Plasma optical modulators for intense lasers

    NASA Astrophysics Data System (ADS)

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

    2016-06-01

    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.

  8. Plasma optical modulators for intense lasers.

    PubMed

    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 10(16) 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

  9. 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

  10. 14th International Conference 'Laser Optics 2010'

    SciTech Connect

    Mak, Artur A

    2010-10-15

    The 14th International Conference 'Laser Optics 2010' in which more than 800 scientists and experts from 35 countries took part, was held from June 28 to July 2, 2010, in St. Petersburg. (information)

  11. Optical Frequency Comb Generation based on Erbium Fiber Lasers

    NASA Astrophysics Data System (ADS)

    Droste, Stefan; Ycas, Gabriel; Washburn, Brian R.; Coddington, Ian; Newbury, Nathan R.

    2016-06-01

    Optical frequency combs have revolutionized optical frequency metrology and are being actively investigated in a number of applications outside of pure optical frequency metrology. For reasons of cost, robustness, performance, and flexibility, the erbium fiber laser frequency comb has emerged as the most commonly used frequency comb system and many different designs of erbium fiber frequency combs have been demonstrated. We review the different approaches taken in the design of erbium fiber frequency combs, including the major building blocks of the underlying mode-locked laser, amplifier, supercontinuum generation and actuators for stabilization of the frequency comb.

  12. 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)

  13. 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.

  14. Improved multipass optics for diode laser spectroscopy

    SciTech Connect

    Hu, T.A.; Chappell, E.L.; Munley, J.T.; Sharpe, S.W. )

    1993-12-01

    Feedback between optical elements can be a major source of noise when trying to attain high sensitivity in infrared absorption experiments. We find that a conventional White-cell optical arrangement introduces etaloning fringes that modulate the peak-to-peak amplitude of our signals by 1 part in 16 666, a fractional change of 6[times]10[sup [minus]5]. Although relatively small, this noise'' is systematic and adds coherently with averaging, obscuring interesting absorption features. An easily constructed multipass optical system suited for performing high-resolution infrared spectroscopy in molecular beams is described. The design is based on a variation of the White cell and has been optimized for use with lead salt diode lasers. One of the key components in the improved design is the addition of an oscillating mirror for spoiling optical feedback generated by laser scatter and/or poor mode coupling of the laser to the multipass optics.

  15. 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. PMID:25401537

  16. 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.

  17. Advanced optic fabrication using ultrafast laser radiation

    NASA Astrophysics Data System (ADS)

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

    2016-03-01

    Advanced fabrication and finishing techniques are desired for freeform optics and integrated photonics. Methods including grinding, polishing and magnetorheological finishing used for final figuring and polishing of such optics are time consuming, expensive, and may be unsuitable for complex surface features while common photonics fabrication techniques often limit devices to planar geometries. Laser processing has been investigated as an alternative method for optic forming, surface polishing, structure writing, and welding, as direct tuning of laser parameters and flexible beam delivery are advantageous for complex freeform or photonics elements and material-specific processing. Continuous wave and pulsed laser radiation down to the nanosecond regime have been implemented to achieve nanoscale surface finishes through localized material melting, but the temporal extent of the laser-material interaction often results in the formation of a sub-surface heat affected zone. The temporal brevity of ultrafast laser radiation can allow for the direct vaporization of rough surface asperities with minimal melting, offering the potential for smooth, final surface quality with negligible heat affected material. High intensities achieved in focused ultrafast laser radiation can easily induce phase changes in the bulk of materials for processing applications. We have experimentally tested the effectiveness of ultrafast laser radiation as an alternative laser source for surface processing of monocrystalline silicon. Simulation of material heating associated with ultrafast laser-material interaction has been performed and used to investigate optimized processing parameters including repetition rate. The parameter optimization process and results of experimental processing will be presented.

  18. Optical-fiber-coupled optical bistable semiconductor lasers

    SciTech Connect

    Zhing Lichen; Tang Yunxin; Qin Ying; Guo Yili

    1986-12-01

    A compact, low input power optical bistable device, consisting of a photodetector, an optical fiber directional coupler, and a semiconductor laser diode, was presented. The principle is described graphically to explain the observed effects such as hysteresis, differential operational gain and memory functions.

  19. Fiber optic mounted laser driven flyer plates

    SciTech Connect

    Paisley, D.L.

    1990-12-31

    This invention is comprised of a laser driven flyer plate where the flyer plate is deposited directly onto the squared end of an optical fiber. The plasma generated by a laser pulse drives the flyer plate toward a target. In another embodiment, a first metal layer is deposited onto the squared end of an optical fiber, followed by a layer of a dielectric material and a second metal layer. The laser pulse generates a plasma in the first metal layer, but the plasma is kept away from the second metal layer by the dielectric layer until the pressure reaches the point where shearing occurs. 2 figs.

  20. 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)

  1. Optical characterization in laser damage studies

    NASA Astrophysics Data System (ADS)

    Commandré, Mireille; Natoli, Jean Yves; Gallais, Laurent; Wagner, Frank; Amra, Claude

    2007-01-01

    The development of high power lasers and optical micro-components requires optical characterization techniques for studying behavior of optical materials under illumination, laser damage phenomena and ageing. More usual optical characterization tools are based on measurements of absorption, scattering and luminescence; they are non destructive evaluation techniques. It is important to combine several tools which allow getting complementary information. Optical tools can be used in damage initiation studies or to characterize properties of damaged areas. Because defects involved in laser damage initiation are sub-micrometer sized, both high spatial resolution and high sensitivity are required to detect defects as small as possible. Furthermore optical tools have to be implemented in damage set-up and at the same wavelength for a detailed analysis of damage mechanisms. We present an overview of recent developments in the field of optical characterization in connection with laser damage. Especially, a high resolution photothermal deflection microscopy has been coupled with a damage set-up to detect nano-absorbing precursors of damage and to study their behavior under irradiation. Thus model defects such as gold inclusions of various sizes have been followed through irradiation and results are compared with numerical simulations. Optical characterization allows to get determining information if several techniques are associated with numerical simulations.

  2. 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.

  3. Projection optics for a laser velocimeter

    NASA Technical Reports Server (NTRS)

    Rhodes, D. B.

    1979-01-01

    Projection optics for laser velocimeter (LV) scans constant focal volume over entire focus-position range. Optics thus simplify LV measurements over large flow fields (such as those encountered in wind tunnels) by eliminating calibrations required when focal volume varies with position.

  4. 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.

  5. 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.

  6. 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.

  7. Nanoglassified, Optically-Active Monolayer Films of Gold Nanoparticles for in Situ Orthogonal Detection by Localized Surface Plasmon Resonance and Surface-Assisted Laser Desorption/Ionization-MS

    PubMed Central

    2015-01-01

    Localized surface plasmon resonance (LSPR) represents a sensitive and versatile method for detection of biomolecules in a label-free fashion, but identification of bound analytes can be challenging with LSPR alone, especially for samples in a complex medium. We report the fabrication of an optically active, plasmonic film of gold nanoparticles by using a self-assembly and calcination process, which offers orthogonal measurements enabling multifaceted characterization on the same surface with LSPR and surface-assisted laser desorption/ionization mass spectrometry. This proof-of-concept study involves plasmonic characterization of the fabricated nanofilm, real-time monitoring of vesicle–surface interactions toward formation of fluid lipid bilayer, and mass spectrometric analysis of peptides and cytochrome c digest. This multifunction-enabling surface material can yield complementary analytical information, providing new tools for comprehensive analysis of biomolecular samples. PMID:25417963

  8. Nanoglassified, optically-active monolayer films of gold nanoparticles for in situ orthogonal detection by localized surface plasmon resonance and surface-assisted laser desorption/ionization-MS.

    PubMed

    Chen, Chih-Yuan; Hinman, Samuel S; Duan, Jicheng; Cheng, Quan

    2014-12-16

    Localized surface plasmon resonance (LSPR) represents a sensitive and versatile method for detection of biomolecules in a label-free fashion, but identification of bound analytes can be challenging with LSPR alone, especially for samples in a complex medium. We report the fabrication of an optically active, plasmonic film of gold nanoparticles by using a self-assembly and calcination process, which offers orthogonal measurements enabling multifaceted characterization on the same surface with LSPR and surface-assisted laser desorption/ionization mass spectrometry. This proof-of-concept study involves plasmonic characterization of the fabricated nanofilm, real-time monitoring of vesicle-surface interactions toward formation of fluid lipid bilayer, and mass spectrometric analysis of peptides and cytochrome c digest. This multifunction-enabling surface material can yield complementary analytical information, providing new tools for comprehensive analysis of biomolecular samples. PMID:25417963

  9. 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.

  10. Dual-Wavelength Internal-Optically-Pumped Semiconductor Laser Diodes

    NASA Astrophysics Data System (ADS)

    Green, Benjamin

    Dual-wavelength laser sources have various existing and potential applications in wavelength division multiplexing, differential techniques in spectroscopy for chemical sensing, multiple-wavelength interferometry, terahertz-wave generation, microelectromechanical systems, and microfluidic lab-on-chip systems. In the drive for ever smaller and increasingly mobile electronic devices, dual-wavelength coherent light output from a single semiconductor laser diode would enable further advances and deployment of these technologies. The output of conventional laser diodes is however limited to a single wavelength band with a few subsequent lasing modes depending on the device design. This thesis investigates a novel semiconductor laser device design with a single cavity waveguide capable of dual-wavelength laser output with large spectral separation. The novel dual-wavelength semiconductor laser diode uses two shorter- and longer-wavelength active regions that have separate electron and hole quasi-Fermi energy levels and carrier distributions. The shorter-wavelength active region is based on electrical injection as in conventional laser diodes, and the longer-wavelength active region is then pumped optically by the internal optical field of the shorter-wavelength laser mode, resulting in stable dual-wavelength laser emission at two different wavelengths quite far apart. Different designs of the device are studied using a theoretical model developed in this work to describe the internal optical pumping scheme. The carrier transport and separation of the quasi-Fermi distributions are then modeled using a software package that solves Poisson's equation and the continuity equations to simulate semiconductor devices. Three different designs are grown using molecular beam epitaxy, and broad-area-contact laser diodes are processed using conventional methods. The modeling and experimental results of the first generation design indicate that the optical confinement factor of the

  11. Optical coatings on laser crystals for HiPER project

    NASA Astrophysics Data System (ADS)

    Oulehla, Jindrich; Pokorný, Pavel; Lazar, Josef

    2011-12-01

    In this contribution we present a technology for deposition of interference coatings for optical components designed to operate as active media in power pulsed lasers. The aim of the technology is to prepare crystals for lasers for the HiPER project (High Power laser Energy Research facility) which should demonstrate the feasibility of laser driven fusion as a future energy source. Diode pumped solid state lasers (DPSSL) are the most likely option for fusion ignition. The choice of the material for the lasers' active medium is critical. Some of the most important properties include the ability to be antireflection coated to reduce the energy losses and increase the overall efficiency. This contribution deals with some of the materials considered to be candidates for slabs serving as the active medium of the DPSSLs. We tested Yb:YAG and Yb:CaF2 samples. As large amounts of heat need to be dissipated during laser operation, cryogenic cooling is necessary. Appropriate coating materials and techniques need to be chosen. Therefore differences between available coating techniques are investigated in terms of adhesion, enduring of stress from temperature shocks, etc. Coated samples were placed into cryogenic environment in order to simulate conditions similar to those in real life operation. Optical microscopy was used for coating investigation after the conducted experiments.

  12. Optical coatings on laser crystals for HiPER project

    NASA Astrophysics Data System (ADS)

    Oulehla, Jindrich; Pokorný, Pavel; Lazar, Josef

    2011-06-01

    In this contribution we present a technology for deposition of interference coatings for optical components designed to operate as active media in power pulsed lasers. The aim of the technology is to prepare crystals for lasers for the HiPER project (High Power laser Energy Research) which should demonstrate the feasibility of laser driven fusion as a future energy source. Diode pumped solid state lasers (DPSSL) are the most likely option for fusion ignition. The choice of material for the lasers active medium is critical. Some of the most important properties include the ability to be antireflection coated to reduce the energy losses and increase the overall efficiency. This contribution deals with some of the materials considered to be candidates for slabs serving as the active medium of the DPSSLs. We tested Yb:YAG, Yb:CaF2 and Yb:KGW samples. As large amounts of heat need to be dissipated during laser operation, cryogenic cooling is necessary. Appropriate coating materials and techniques need to be chosen. Therefore differences between available coating techniques are investigated in terms of adhesion, enduring of stress resulting from temperature shocks, etc. Coated samples were placed in a specially designed cryogenic apparatus in order to simulate conditions similar to those in real life operation. Optical microscopy and spectrophotometer measurements were used for coating investigation after the conducted experiments.

  13. Broadband phase-coherent optical frequency synthesis with actively linked Ti:sapphire and Cr:forsterite femtosecond lasers.

    PubMed

    Bartels, Albrecht; Newbury, Nathan R; Thomann, Isabell; Hollberg, Leo; Diddams, Scott A

    2004-02-15

    We link the output spectra of a Ti:sapphire and a Cr:forsterite femtosecond laser phase coherently to form a continuous frequency comb with a wavelength coverage of 0.57-1.45 microm at power levels of 1 nW to 40 microW per frequency mode. To achieve this, the laser repetition rates and the carrier-envelope offset frequencies are phase locked to each other. The coherence time between the individual components of the two combs is 40 micros. The timing jitter between the lasers is 20 fs. The combined frequency comb is self-referenced for access to its overall offset frequency. We report the first demonstration to our knowledge of an extremely broadband and continuous, high-powered and phase-coherent frequency comb from two femtosecond lasers with different gain media. PMID:14971767

  14. Using an eye-safe laser rangefinder to assist active and passive electro-optical sensor performance prediction in low visibility conditions

    NASA Astrophysics Data System (ADS)

    Steinvall, Ove; Persson, Rolf; Berglund, Folke; Gustafsson, Ove; Öhgren, Johan; Gustafsson, Frank

    2015-07-01

    Laser rangefinders are used in various electro-optical (EO) fire control systems. They often operate at eye-safe wavelengths around 1.55 μm, which extends their utility. The paper investigates the use of a modified eye-safe laser rangefinder at 1.55 μm to obtain information on atmospheric attenuation and couple that information to the performance of active and passive EO sensors with an emphasis of lower visibility conditions. Such information can be of great value both for estimating own sensor capabilities at a given moment as well as estimating the threat capability. One obvious example is ship defense where it is difficult to obtain visibility along variable and slant atmospheric paths, especially in darkness. The experimental equipment and the results from measurements of atmospheric backscatter along various atmospheric paths are presented. The backscatter curve is used to evaluate the extinction. These extinction values are compared with those deduced from a point visibility meter and from echo measurements against two similar nets positioned at two ranges from the sensor. TV and IR images of test targets along a 1.8 km path close to sea surface in the Baltic Sea were collected in parallel with the lidar. A weather station and a scintillometer collected weather and turbulence parameters. Results correlating the lidar attenuation with the imaging performance will be given.

  15. 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.

  16. AFIRE: fiber Raman laser for laser guide star adaptive optics

    NASA Astrophysics Data System (ADS)

    Bonaccini Calia, D.; Hackenberg, W.; Chernikov, S.; Feng, Y.; Taylor, L.

    2006-06-01

    Future adaptive optics systems will benefit from multiple sodium laser guide stars in achieving satisfactory sky coverage in combination with uniform and high-Strehl correction over a large field of view. For this purpose ESO is developing with industry AFIRE, a turn-key, rack-mounted 589-nm laser source based on a fiber Raman laser. The fiber laser will deliver the beam directly at the projector telescope. The required output power is in the order of 10 W in air per sodium laser guide star, in a diffraction-limited beam and with a bandwidth of < 2 GHz. This paper presents the design and first demonstration results obtained with the AFIRE breadboard. 4.2W CW at 589nm have so far been achieved with a ~20% SHG conversion efficiency.

  17. 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,…

  18. Relaxation oscillations in optically pumped molecular lasers

    NASA Technical Reports Server (NTRS)

    Lawandy, N. M.; Koepf, G. A.

    1980-01-01

    The observation of relaxation oscillations in both the (C-13)H3F and (C-12)H3F optically pumped lasers is reported. Expressions are derived for the oscillation frequency and its temperature and pressure dependences using a four-level rate equation model. Excellent agreement between measured frequencies and the theory presented is observed. Models are considered for using this phenomenon to determine the rotational and vibrational relaxation mechanisms of the laser gases.

  19. Optical transceiver platform for laser communication experiments

    NASA Astrophysics Data System (ADS)

    Coffelt, Everett L.; Ebben, Thomas H.

    1986-01-01

    This paper describes a laser communication (lasercom) transceiver platform to be used for laboratory experiments. The platform features a directly modulated semiconductor laser, avalanche photodiode receiver, and microprocessor-controlled acquisition and tracking system. The platform provides a test-bed, enabling study in vital areas of lasercom hardware such as system performance versus link distance, optical power, tracking accuracy, and subsystem and component characterization for future system specifications, including critical areas limiting present system performance.

  20. 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.]. PMID:27548458

  1. Optical Undulators for Free Electron Lasers

    NASA Astrophysics Data System (ADS)

    Lawler, James; Bisognano, Joseph; Bosch, Robert; Green, Michael; Jacobs, Kenneth; Yavuz, Deniz

    2014-05-01

    Free Electron Lasers (FELs) in the x-ray region are opening new research directions in AMO physics and other fields, but beam time is quite limited at these expensive facilities. There are conceptual designs for much less expensive soft x-ray FELs using sheared pulses from Table Top Terawatt (T3) lasers as optical undulators. A nearly co-propagating laser pulse can be angle tuned to yield soft x-rays, and shearing the pulse can optimize use of the laser photons. Undulator K values near unity are available from T3 lasers, and angle tuning provides almost arbitrary effective undulator periods. A combination of these optical undulator ideas with pre-``micro-bunching'' at a photocathode followed by electron beam emittance exchange can reduce the energy needed from the T3 laser. A combination of a nearly co-propagating optical undulator with a Bragg-reflection diamond mirror cavity may lower the cost of an x-ray frequency comb for metrology.

  2. 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.

  3. 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.

  4. 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.

  5. 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. PMID:27140558

  6. Optical fiber laser of multifrequency emission

    NASA Astrophysics Data System (ADS)

    Beltrán-Pérez, Georgina; Jacobo Aispuro, Liliana; Lucian Rocha, Froylan; Castillo Mixcóatl, Juan; Múñoz Aguirre, Severino

    2007-03-01

    The wavelength division multiplexor (WDM) has a great importance in the technology of the communications by optical fiber, is an economic and efficient form, to increase the capacity of transmission by several orders of magnitude, reason why it is desirable to have laser sources of multiple wavelengths in a system WDM, which, according to reported works, have been obtained using diverse types of filters. In this work we presented a laser of multifrequency emission, of Erbium doped optical fiber, tuned with an optical fiber filter. The configuration of the optical filter, presents high stability and low lost by insertion, independence to the changes of polarization, low powers of light entrance, and has an useful spectral wide. It has the advantage to have a simple design and easy manufacture in addition to his low losses.

  7. Carbon Dioxide Laser Fiber Optics In Endoscopy

    NASA Astrophysics Data System (ADS)

    Fuller, Terry A.

    1982-12-01

    Carbon dioxide laser surgery has been limited to a great extent to surgical application on the integument and accessible cavities such as the cervix, vagina, oral cavities, etc. This limitation has been due to the rigid delivery systems available to all carbon dioxide lasers. Articulating arms (series of hollow tubes connected by articulating mirrors) have provided an effective means of delivery of laser energy to the patient as long as the lesion was within the direct line of sight. Even direct line-of-sight applications were restricted to physical dimension of the articulating arm or associated hand probes, manipulators and hollow tubes. The many attempts at providing straight endoscopic systems to the laser only stressed the need for a fiber optic capable of carrying the carbon dioxide laser wavelength. Rectangular and circular hollow metal waveguides, hollow dielectric waveguides have proven ineffective to the stringent requirements of a flexible surgical delivery system. One large diameter (1 cm) fiber optic delivery system, incorporates a toxic thalliumAbased fiber optic material. The device is an effective alternative to an articulating arm for external or conventional laser surgery, but is too large and stiff to use as a flexible endoscopic tool. The author describes the first highly flexible inexpensive series of fiber optic systems suitable for either conventional or endoscopic carbon dioxide laser surgery. One system (IRFLEX 3) has been manufactured by Medlase, Inc. for surgical uses capable of delivering 2000w, 100 mJ pulsed energy and 15w continuous wave. The system diameter is 0.035 inches in diameter. Surgically suitable fibers as small as 120 um have been manufactured. Other fibers (IRFLEX 142,447) have a variety of transmission characteristics, bend radii, etc.

  8. Lasers and space optical systems study

    NASA Astrophysics Data System (ADS)

    Giuliano, Concetto; Annaballi, Angela L.

    1998-01-01

    The Air Force and other government organizations have considered the application of space-based lasers since the early 1970s. Recent studies have identified the enormous potential of lasers and optical systems in space to support the Full-Spectrum Dominance envisioned by the Joint Chiefs of Staff in ``Joint Vision 2010.'' The Air Force Research Laboratory has undertaken the LAsers and S_pace O_ptical S_ystems (LASSOS) Study to examine in detail how space lasers and optics (defined as any laser system based in space or any terrestrial-based laser whose beam transits space) could best be used to satisfy this critical need. This twelve-month study will identify promising technology concepts for space laser/optic systems, develop system concepts based on these technologies with special emphasis on systems capable of performing multiple missions, assess how well these systems can accomplish operational tasks in a quantitative manner, and design technology development roadmaps for selected concepts. Since work on the study had commenced only days before the publication deadline, this manuscript is necessarily limited to a description of the background, motivation, and organization of the study. The ``Concept Definition'' phase of the study is scheduled to be completed by the time of the STAIF conference. By that time, study participants will have identified key concepts that best satisfy criteria for timely and cost-effective augmentation of combat capability. A final report, which will be made available to authorized recipients, will be written after completion of the study in August 1998.

  9. Acousto-optic filter for electronic laser tuning

    NASA Technical Reports Server (NTRS)

    Harris, S. E.

    1972-01-01

    Electronically tunable lithium niobate filter utilizes acoustic-optic diffraction for tuning laser to desired frequencies. Filter placed inside laser cavity diffracts incident optical signal of one polarization into orthogonal polarization by collinearly propagating acoustic beam to desired wavelength.

  10. 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.

  11. 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. PMID:24690788

  12. 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.

  13. Excimer laser machining of optical fiber taps

    NASA Astrophysics Data System (ADS)

    Coyle, Richard J.; Serafino, Anthony J.; Grimes, Gary J.; Bortolini, James R.

    1991-05-01

    Precision openings for construction of an optical backplane have been machined in an optical fiber using an excimer laser operating at a wavelength of 193 nm. The openings were made by imaging the laser beam onto the polymer fiber cladding with a telescope, then ablating the cladding with a sufficient number of pulses to expose the core. Circular openings measuring 250 and 625 microns and elliptical openings measuring 650 X 350 microns have been made in the cladding of a 1 mm polymer-clad silica fiber. Examination by scanning electron microscopy reveals that the best quality openings are obtained with either the smaller circular geometry or the elliptical geometry. For various reasons, elliptical openings, with the major axis oriented along the longitudinal axis of the fiber, appear more suitable for tap construction. Individual optical fiber taps have been constructed by attaching a tap fiber to a laser machined opening in a central fiber using an ultraviolet-curable acralate. Individual tap measurements were made on the elliptical and the 250 micron circular openings. In addition, a triple tap assembly was made using elliptical tap openings. These results indicate that the excimer laser machining technique may be applicable to the construction of a linear tapped bus for optical backplanes.

  14. Miniaturized symmetrization optics for junction laser

    NASA Technical Reports Server (NTRS)

    Hammer, Jacob M. (Inventor); Kaiser, Charlie J. (Inventor); Neil, Clyde C. (Inventor)

    1982-01-01

    Miniaturized optics comprising transverse and lateral cylindrical lenses composed of millimeter-sized rods with diameters, indices-of-refraction and spacing such that substantially all the light emitted as an asymmetrical beam from the emitting junction of the laser is collected and translated to a symmetrical beam.

  15. 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…

  16. 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.

  17. 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.

  18. Airborne visible laser optical communication experiment.

    NASA Technical Reports Server (NTRS)

    Randall, J. L.

    1972-01-01

    A series of optical communication experiments between a high altitude aircraft at 18.3 km (60,000 ft) and a ground station are planned by NASA in the summer of 1972. The basic concept is that an optical tracker and transmitter will be located in each terminal. The aircraft transceiver consists of a 5-mW HeNe laser transmitter with a 30-megabit modulator. The ground station beacon is an argon laser operating at 488 nm. A separate pulsed laser radar is used for initial acquisition. The objective of the experiment is to obtain engineering data on the precision tracking and communication system performance at both terminals. Atmospheric effects on the system performance are of prime importance.

  19. 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.

  20. Nonlinear optical properties of the active medium in intracavity phase conjugation of the radiation of a pulsed electron-beam-controlled discharge CO{sub 2} laser. I. Experiments

    SciTech Connect

    Galushkin, M G; Mitin, Konstantin V; Ionin, Andrei A; Kotkov, A A; Seleznev, L V

    1998-08-31

    An experimental investigation was made of phase conjugation in the course of intracavity degenerate four-wave mixing of radiation in the active medium of a pulsed electron-beam-controlled discharge CO{sub 2} laser generating long pulses. An analysis was carried out of the dependences of the energy and temporal characteristics of a phase-conjugated signal on the specific input energy deposited in the electron-beam-controlled discharge, on the Q-factor of the laser cavity, on the composition and pressure of the laser-active mixture, on the angle of interaction and optical delay between the probe and reference waves, on the ratio of the intensities of these two waves, and on the polarisation and spectral composition of laser radiation. The energy reflection coefficient of the phase-conjugated signal increased with increase in the input energy and with reduction in the probe wave intensity. An increase in the proportion of nitrogen and a reduction in the proportion of helium in the laser-active mixture increased the reflection coefficient and gave rise to a specific profile of the phase-conjugated signal with two maxima, attributed to amplitude and phase nonlinearities of the active medium. An increase in the specific input energy and of the cavity Q-factor reduced the response time of the phase-conjugate signal. (nonlinear optical phenomena and devices)

  1. Compact multipass optical cell for laser spectroscopy.

    PubMed

    Tuzson, Béla; Mangold, Markus; Looser, Herbert; Manninen, Albert; Emmenegger, Lukas

    2013-02-01

    A multipass cell (MPC) design for laser absorption spectroscopy is presented. The development of this new type of optical cell was driven by stringent criteria for compactness, robustness, low volume, and ease of use in optical systems. A single piece of reflective toroidal surface forms a near-concentric cavity with a volume of merely 40 cm(3). Contrary to traditional MPCs, this design allows for flexible path-length adjustments by simply changing the aiming angle of the laser beam at the entrance window. Two effective optical path lengths of 2.2 and 4.1 m were chosen to demonstrate the cell's suitability for high-precision isotope ratio measurements of CO(2) at 1% and ambient mixing ratio levels. PMID:23381403

  2. 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.

  3. Active laser tweezers microrheometry of microbial biofilms

    NASA Astrophysics Data System (ADS)

    Osterman, N.; Slapar, V.; Boric, M.; Stopar, D.; Babič, D.; Poberaj, I.

    2010-08-01

    Microbial biofilms are present on biotic and abiotic surfaces and have a significant impact on many fields in industry, health care and technology. Thus, a better understanding of processes that lead to development of biofilms and their chemical and mechanical properties is needed. In the following paper we report the results of active laser tweezers microrheology study of optically inhomogeneous extracellular matrix secreted by Visbrio sp. bacteria. One particle and two particle active microrheology were used in experiments. Both methods exhibited high enough sensitivity to detect viscosity changes at early stages of bacterial growth. We also showed that both methods can be used in mature samples where optical inhomogeneity becomes significant.

  4. 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.

  5. 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.

  6. Optical metrology devices for high-power laser large optics

    NASA Astrophysics Data System (ADS)

    Daurios, J.; Bouillet, S.; Gaborit, G.; Poncetta, J. C.

    2007-06-01

    High power laser systems such as the LMJ laser or the LIL laser, its prototype, require large optical components with very strict and various specifications. Technologies used for the fabrication of these components are now usually compatible of such specifications, but need the implementation at the providers' sites of different kind of metrology like interferometry, photometry, surface inspection, etc., systematically performed on the components. So, during the production for the LIL and now for the LMJ, CEA has also equipped itself with a wide range of specific metrology devices used to verify the effective quality of these large optics. These various systems are now used to characterize and validate the LMJ vendors' processes or to perform specific controls dedicated to analyzes which are going further than the simple "quality control" of the component (mechanical mount effect, environment effect, ageing effect,...). After a short introduction on the LMJ laser and corresponding optical specifications for components, we will focus on different metrology devices concerning interferometry and photometry measurements or surface inspection. These systems are individually illustrated here by the mean of different results obtained during controls done in the last few years.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. Optical isolators for 2-micron fibre lasers

    NASA Astrophysics Data System (ADS)

    Stevens, Gary; Legg, Thomas H.; Shardlow, Peter

    2015-02-01

    We report on the development and testing of optical isolators for use in 2-micron fiber laser systems. A variety of potential Faraday rotator materials were characterised to identify the most suitable materials for use in the 1700-2100nm wavelength range. Isolators based on the three best performing materials were then developed and packaged as fiber-in, fiber-out and fiber-in, beam-out devices. The isolators were then tested in CW, pulsed and ultrafast laser systems. The three different designs produced different performance characteristics, but all designs demonstrated isolation >25dB and insertion losses of <1.2 dB.

  13. 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.

  14. 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.

  15. Improved optics for laser light scattering

    NASA Technical Reports Server (NTRS)

    Cheung, H. Michael

    1989-01-01

    Laser light scattering experiments contemplated for use in a microgravity environment must conform to a number of operational constraints which do not apply on Earth. In particular, the use of index matching fluid to control flare is unacceptable. Work to eliminate index matching fluids by the use of high spatial resolution receiving optics is described. By increasing on-axis spatial resolution flare from the sample cell walls (both the cell sample and cell air interfaces) can be effectively prevented from reaching the photodetector. In general, improving the on-axis discrimination degrades the angular resolution of a receiving optical train. Several different possible configurations of receiving optics are compared for their spatial resolution and angular resolution. For cylinder symmetric optics, the dual lens, fourier transform pair, receiving train with a center mask located between the lenses gives the best on-axis spatial resolution.

  16. 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.

  17. 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.

  18. Electro-optic and acousto-optic laser beam scanners

    NASA Astrophysics Data System (ADS)

    Heberle, Johannes; Bechtold, Peter; Strauß, Johannes; Schmidt, Michael

    2016-03-01

    Electro-optical deflectors (EOD) and acousto-optical deflectors (AOD) are based on deflection of laser light within a solid state medium. As they do not contain any moving parts, they yield advantages compared to mechanical scanners which are conventionally used for laser beam deflection. Even for arbitrary scan paths high feed rates can be achieved. In this work the principles of operation and characteristic properties of EOD and AOD are presented. Additionally, a comparison to mirror based mechanical deflectors regarding deflection angles, speed and accuracy is made in terms of resolvable spots and the rate of resolvable spots. Especially, the latter one is up to one order of magnitude higher for EOD and AOD systems compared to conventional systems. Further characteristic properties such as response time, damage threshold, efficiency and beam distortions are discussed. Solid state laser beam deflectors are usually characterized by small deflection angles but high angular deflection velocities. As mechanical deflectors exhibit opposite properties an arrangement of a mechanical scanner combined with a solid state deflector provides a solution with the benefits of both systems. As ultrashort pulsed lasers with average power above 100 W and repetition rates in the MHz range have been available for several years this approach can be applied to fully exploit their capabilities. Thereby, pulse overlap can be reduced and by this means heat affected zones are prevented to provide proper processing results.

  19. Laser tomography adaptive optics: a performance study.

    PubMed

    Tatulli, Eric; Ramaprakash, A N

    2013-12-01

    We present an analytical derivation of the on-axis performance of adaptive optics systems using a given number of guide stars of arbitrary altitude, distributed at arbitrary angular positions in the sky. The expressions of the residual error are given for cases of both continuous and discrete turbulent atmospheric profiles. Assuming Shack-Hartmann wavefront sensing with circular apertures, we demonstrate that the error is formally described by integrals of products of three Bessel functions. We compare the performance of adaptive optics correction when using natural, sodium, or Rayleigh laser guide stars. For small diameter class telescopes (≲5 m), we show that a small number of Rayleigh beacons can provide similar performance to that of a single sodium laser, for a lower overall cost of the instrument. For bigger apertures, using Rayleigh stars may not be such a suitable alternative because of the too severe cone effect that drastically degrades the quality of the correction. PMID:24323009

  20. Picosecond electron-optic diagnostics in laser studies

    NASA Astrophysics Data System (ADS)

    Prokhorov, A. M.

    The papers included in this volume provide an overview of research aimed at the development of methods and instrumentation for ultrahigh-speed electron-optic detection and of their applications in laser physics, laser fusion, fiber-optic communication, picosecond spectroscopy, and photobiology. Topics discussed include the physics of a picosecond electron-optic converter, the aberration theory for cathode lenses, picosecond and subpicosecond laser sources, and a beam deflection system for a subpicosecond electron-optic converter.

  1. 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

  2. Optical properties of laser spinel

    NASA Astrophysics Data System (ADS)

    Mironova-Ulmane, Nina; Skvortsova, Vera; Smirnovs, Andrejs; Riekstinya, Daina; Litvinov, L.; Sildos, Ilmo; Osvet, Andris

    1997-02-01

    The present work summarizes the results of absorption and luminescence spectra investigation of natural and synthetic magnesium aluminum spinels (MgO*nAl2O3) containing chromium and manganese ions. The spectra have been analyzed with an aim to determine the effect of stoichiometry 'n' on distribution of emitting ions. The Mn2+ is observed in both tetrahedral and octahedral coordinations providing green or orange emission. Absorption bands have been explained in terms of the Mn2+ configuration model. Laser excitation of chromium-comprising magnesium aluminum spinel crystals has been carried out at 7 K with the purpose to detect the nearest neighbors of Cr3+ ions. Luminescence emission spectra have been obtained for natural sample and three synthetic samples (MgO*nAl2O3, n equals 1, 2, 2.8). Decay time has been measured at different wavelengths and compared for crystals of different stoichiometry. In case n equals 2 or 2.8, computer simulation has been used to decompose smeared luminescence spectra in the 680 - 700 nm region. Gaussian curves corresponding to R- and N-lines of natural spinel spectrum have been applied as components in the calculations of nonstoichiometric spinel spectra. This suggests that there aren't normally arranged Cr-occupied octahedral positions in nonstoichiometric spinel (n equals 2.8, e.g.).

  3. Nonlinear optical properties of the active medium in intracavity phase conjugation of the radiation of a pulsed electron-beam-controlled discharge CO{sub 2} laser. II. Theoretical analysis

    SciTech Connect

    Galushkin, M G; Mitin, Konstantin V; Ionin, Andrei A; Kotkov, A A

    1998-10-31

    Numerical simulation is used as the basis of an analysis of nonlinear optical properties of the active medium in intracavity four-wave mixing of the radiation of a pulsed electron-beam-controlled discharge CO{sub 2} laser on saturated-gain and refractive-index diffraction gratings. The reflection coefficient of the phase-conjugated signal is determined for various cavity Q-factors, specific input energies, and pressures of the laser-active mixture. A comparison is made of the theoretical and experimental results. It is found that the rate of formation of amplitude gratings is governed primarily by the initial population inversion and by the intensities of the interacting waves. It is shown that transient phase gratings make the dominant contribution to the phase-conjugate reflection coefficient at high pressures of the mixture. (nonlinear optical phenomena)

  4. Pulsed laser damage to optical fibers

    SciTech Connect

    Allison, S.W.; Gillies, G.T.; Magnuson, D.W.; Pagano, T.S.

    1985-10-01

    This paper describes some observations of pulsed laser damage to optical fibers with emphasis on a damage mode characterized as a linear fracture along the outer core of a fiber. Damage threshold data are presented which illustrate the effects of the focusing lens, end-surface preparation, and type of fiber. An explanation based on fiber-beam misalignment is given and is illustrated by a simple experiment and ray trace.

  5. Key optical components for spaceborne lasers

    NASA Astrophysics Data System (ADS)

    Löhring, J.; Winzen, M.; Faidel, H.; Miesner, J.; Plum, D.; Klein, J.; Fitzau, O.; Giesberts, M.; Brandenburg, W.; Seidel, A.; Schwanen, N.; Riesters, D.; Hengesbach, S.; Hoffmann, H.-D.

    2016-03-01

    Spaceborne lidar (light detection and ranging) systems have a large potential to become powerful instruments in the field of atmospheric research. Obviously, they have to be in operation for about three years without any maintenance like readjusting. Furthermore, they have to withstand strong temperature cycles typically in the range of -30 to +50 °C as well as mechanical shocks and vibrations, especially during launch. Additionally, the avoidance of any organic material inside the laser box is required, particularly in UV lasers. For atmospheric research pulses of about several 10 mJ at repetition rates of several 10 Hz are required in many cases. Those parameters are typically addressed by DPSSL that comprise components like: laser crystals, nonlinear crystals in pockels cells, faraday isolators and frequency converters, passive fibers, diode lasers and of course a lot of mirrors and lenses. In particular, some components have strong requirements regarding their tilt stability that is often in the 10 μrad range. In most of the cases components and packages that are used for industrial lasers do not fulfil all those requirements. Thus, the packaging of all these key components has been developed to meet those specifications only making use of metal and ceramics beside the optical component itself. All joints between the optical component and the laser baseplate are soldered or screwed. No clamps or adhesives are used. Most of the critical properties like tilting after temperature cycling have been proven in several tests. Currently, these components are used to build up first prototypes for spaceborne systems.

  6. Singularity of influence of stochastic and order phase structures on optical quality of gas-dynamic laser active medium flow

    NASA Astrophysics Data System (ADS)

    Kovalevsky, Valery O.; Lobachev, Vitaly V.

    2002-02-01

    Detail analysis of active medium flow structure is presented. Schlieren method photography of flow is processed to reconstruct parameters both stochastic and order phase components. Properties of random part including correlation function, spectrum of spatial frequency, scale of turbulence, are determined by digital filtering. It was possible to compare influence of random and regular phase distortions on radiation divergence structure.

  7. Optical Pattern Generator Using Excimer Laser

    NASA Astrophysics Data System (ADS)

    Hafner, Bernhard F.

    1988-01-01

    Reticles (masks on enlarged scale) are needed for optical pattern transfer in the production of integrated semiconductor circuits. In order to meet present requirements for 5X reticles only a direct writing technique is feasible. This means direct exposing of photoresist either with light or an electron beam. Many of todays highly dense reticles require some 10 5 to 10 6 discrete exposures when generated with an optical pattern generator. Optical pattern generators normally use mercury arc lamps to expose positive photoresist, which in turn need 200 milliseconds for each of these discrete exposures, thus requiring to stop the table at every exposure position ("stop and go" mode). This results in running times of several days per reticle. Therefore most reticles are nowadays being manufactured with very expensive e-beam machines. In the early 80's we started the first experiments to expose photoresist with an excimer laser. In order to obtain the maximum gain in speed, the goal was to operate with only one excimer laser pulse per exposure, so that a fast "flash on the fly" operation with an optical pattern generator became true. Equipping a conventional optical pattern generator with an excimer laser as the light source, it has become possible to expose substrates coated with standard photoresist in the "flash on the fly" mode with only 13 nanoseconds per flash. So the thruput could be increased up to 25 times in comparison to a pattern generator equipped with a mercury lamp. A comparison of both operation modes will show that an immense increase of speed is possible, even when a ten years old M3600 pattern generator is used. This system is in function now with very high reliability since more than three years in our IC development line.

  8. Application of repumping laser in optical switching

    NASA Astrophysics Data System (ADS)

    Ray, Ayan; Ali, Md. Sabir; Chakrabarti, Alok

    2014-08-01

    The application of electromagnetically induced transparency (EIT) in high speed optical switching has remained as a key topic in research related to all optical switching. Demonstration of optical switching through EIT realized under ladder (Ξ) level coupling has been reported earlier. Due to narrow linewidth (ГEIT) and low coherent dephasing rate (γ) the EIT needs to be prepared only once to demonstrate such switching action. However, in a Ξ system the EIT is accompanied with double resonance optical pumping (DROP) signal, which is limited by spontaneous decay (Г) rates. It has been shown by our group that the simultaneous presence of DROP-EIT combination paves the way for executing a kind of slow-fast switching action. However the focus always remain on improving the modulation depth in such type of coherence assisted switch. Here we report a possible way to improve modulation depth by using an additional (named 'repumping' after convention used in laser cooling experiments) laser in the Ξ system. The 5S1/2→5P3/2→5D5/2 level coupling scheme of 87Rb atom is used in the current experiment.

  9. Russian collaborations on lasers and advanced optics

    SciTech Connect

    Munroe, J.; Cooper, D.; Koym, V.; Salesky, E.

    1996-09-01

    This is the final report of a one-year, Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory. There are several technological areas where the Russians appear to be well ahead of the West. Russian work in lasers and advanced optics, high power nonlinear optics, and optical phase conjugation in particular, are some of these areas. The objective of this project is to establish collaboration with key Russian scientists in this area to analytically and experimentally validate the technologies and identify potential applications. This technology has the potential to solve very important military, civil, and commercial problems. The emphasis of this project is on civil and commercial applications, but the technologies have dual-use applications.

  10. 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.

  11. 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.

  12. 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.

  13. 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. PMID:26367642

  14. Ultrasonic Technology for Characterizing Laser Damage in Optics

    SciTech Connect

    Thomas, G; Martin, L P; Chambers, D

    2002-04-30

    An ultrasonic technique was developed to detect and characterize laser damage in critical optics. During normal usage, sub critical flaws induced by high laser fluence can grow to critical size and potentially can cause unanticipated failure of the optics. This ultrasonic technique monitors the optic in situ and provides a quick, reliable way to quantify the location, number and, ultimately, the size of defects that may initiate and grow during firing of the laser. The feasibility of detecting and sizing laser-induced damage with an ultrasonic technology was theoretically and experimentally demonstrated. An experiment was conducted whereby ultrasonic data was acquired in situ on an optic as it was damaged by a laser. This monitoring of laser induced damage clearly demonstrated the potential for ultrasonic monitoring of critical optics for laser-induced damage.

  15. Adaptive Optics with Sodium Laser Guide Stars

    NASA Astrophysics Data System (ADS)

    Lloyd-Hart, M.; Angel, J. R. P.; Jacobsen, B.; Wittman, D.; McCarthy, D.; Martinez, T.

    1994-12-01

    Adaptive optics requires a reference source of light in the sky to measure wavefront aberration introduced by atmospheric turbulence. Natural stars are ideal for this purpose, but the density of bright stars is not sufficient to provide complete sky coverage. The problem can be overcome with an artificial beacon generated from resonant backscattering off mesospheric sodium atoms exited by a low-power laser tuned to the D2 resonance. Recent experiments at the Multiple Mirror Telescope (MMT) have demonstrated for the first time that an adaptive optics system using a sodium laser guide beacon can be used to improve the imaging quality of the telescope. A beacon of mv = 10.4 was used to control the relative image motion between two of the six apertures of the MMT, while a natural star was used to measure the absolute tilt. A factor of two improvement in the K-band Strehl ratio was measured, and the resolution improved from 0(\\?.58) to 0(\\?.41) . The experiment demonstrated all the features needed for correction of telescopes of 6.5 to 8-m diameter to the diffraction limit in the near infrared with a single sodium laser beacon.

  16. Wave-Chaotic Optical Resonators and Lasers

    NASA Astrophysics Data System (ADS)

    Stone, A. Douglas

    2001-10-01

    Deformed cylindrical and spherical dielectric optical resonators and lasers are analyzed from the perspective of non-linear dynamics and quantum chaos theory. In the short-wavelength limit such resonators behave like billiard systems with non-zero escape probability due to refraction. A ray model is introduced to predict the resonance lifetimes and emission patterns from such a cavity. A universal wavelength-independent broadening is predicted and found for large deformations of the cavity. However there are significant wave-chaotic corrections to the model which arise from chaos-assisted tunneling and dynamical localization effects. Highly directional emission from lasers based on these resonators is predicted from chaotic "whispering gallery" modes for index of refraction less than two. The detailed nature of the emission pattern can be understood from the nature of the phase-space flow in the billiard, and a dramatic variation of this pattern with index of refraction is found due to an effect we term "dynamical eclipsing". Semiconductor lasers of this type also show highly directional emission and high output power but from different modes associated with periodic orbits, both stable and unstable. A semiclassical approach to these modes is briefly reviewed. These asymmetric resonant cavities (ARCs) show promise as components in future integrated optical devices, providing perhaps the first application of quantum chaos theory.

  17. 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.

  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. 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

  20. 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.

  1. 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.

  2. Optics activity for hospitalized children

    NASA Astrophysics Data System (ADS)

    Gargallo, Ana; Gómez-Varela, Ana I.; González-Nuñez, Hector; Delgado, Tamara; Almaguer, Citlalli; Cambronero, Ferran; Garcia-Sanchez, Angel; Flores-Arias, Maria T.

    2014-08-01

    USC-OSA is a student chapter whose objective is to bring Optics knowledge closer to the non-optics community. The activity developed at the Hospital school was one of the most important last year. It was consisted in a few Optics experiments and workshops with hospitalized children of different ages and pathologies. The experiments had to be adapted to their physical conditions with the aim of everyone could participate. We think this activity has several benefits including spreading Optics through children meanwhile they have fun and forget their illness for a while.

  3. Optically pumped Na/sub 2/ laser

    SciTech Connect

    Kanorskii, S.I.; Kaslin, V.M.; Yakushev, O.F.

    1980-10-01

    A pulsed copper vapor laser emitting the 578.2 nm line was used as the pump source in achieving stimulated emission as a result of the electronic A/sup 1/..sigma../sup +//sub u/ to X/sup 1/..sigma../sup +//sub g/ transitions in the Na/sub 2/ molecule in the spectral range 0.765 to 0.804 ..mu... The average power of all the emission lines was 10 mW when the pulsed pump power was 150 W and the efficiency of conversion of the optical pump energy was about 3%. The pulse repetition frequency was 3.3 kHz. Violet diffuse radiation of the Na/sub 2/ molecules, generated by pumping with the copper vapor laser, was observed. The superradiance regime was found for some of the lines.

  4. Damage thresholds in laser irradiated optical materials

    SciTech Connect

    Guignard, F.; Autric, M.; Baudinaud, V.

    1997-12-01

    An experimental study on the damage induced by laser irradiation on different materials, borosilicate glass, fused silicate, moulded and stretched polymethylmethacrylate (PMMA), has been performed. The irradiation source is a 1KJ pulsed cold cathode electron gun preionized TEA CO{sub 2} laser. Damage mechanisms are controlled by the in-depth absorption of the 10,6 {mu}m radiation according to the Beer-Lambert law. The heating of the interaction area gives rise to thermal or thermo-mechanical damages. PMMA is damaged following a boiling process. Stretched PMMA is fractured first, releasing stresses, then boiled like moulded PMMA at higher energy. BK7 crazed after the irradiation due to thermomechanical stresses, silicate melt and vaporized. Optical damages have been characterized by measuring the contrast transfer function through the irradiated samples.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. From laser ultrasonics to optical manipulation.

    PubMed

    Požar, Tomaž; Babnik, Aleš; Možina, Janez

    2015-03-23

    During the interaction of a laser pulse with the surface of a solid object, the object always gains momentum. The delivered force impulse is manifested as propulsion. Initially, the motion of the object is composed of elastic waves that carry and redistribute the acquired momentum as they propagate and reflect within the solid. Even though only ablation- and light-pressure-induced mechanical waves are involved in propulsion, they are always accompanied by the ubiquitous thermoelastic waves. This paper describes 1D elastodynamics of pulsed optical manipulation and presents two diametrical experimental observations of elastic waves generated in the confined ablation and in the radiation pressure regime. PMID:25837135

  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. Femtosecond laser pulse induced birefringence in optically isotropic glass.

    SciTech Connect

    Vawter, Gregory Allen; Luk, Ting Shan; Guo, Junpeng; Yang, Pin; Burns, George Robert

    2003-07-01

    We used a regeneratively amplified Ti:sapphire femtosecond laser to create optical birefringence in an isotropic glass medium. Between two crossed polarizers, regions modified by the femtosecond laser show bright transmission with respect to the dark background of the isotropic glass. This observation immediately suggests that these regions possess optical birefringence. The angular dependence of transmission through the laser-modified region is consistent with that of an optically birefringent material. Laser-induced birefringence is demonstrated in different glasses, including fused silica and borosilicate glass. Experimental results indicate that the optical axes of laser-induced birefringence can be controlled by the polarization direction of the femtosecond laser. The amount of laser-induced birefringence depends on the pulse energy level and number of accumulated pulses.

  13. Active figure maintenance control using an optical truss laser metrology system for a space-based far-IR segmented telescope

    NASA Technical Reports Server (NTRS)

    Lau, Kenneth; Breckenridge, Bill; Nerheim, Noble; Redding, David

    1992-01-01

    A two-stage active control approach was developed addressing the figure control problem for a spaceborne FIR telescope, the Precision Segmented Reflectors Focus Moderate Mission Telescope (FMMT). The first active control stage aligns the optical segments based on images; attention is here given to the second stage, active figure maintenance control system, which maintains the alignment of the optical elements between initializations to hold the mirror figure steady while obtaining data and fixes translational and rotational changes of the optical segments induced by long-term thermal drifts of the support structure. Errors are expected to be 10-100 microns at the nodes of the primary backup structure over the course of an orbit. An rms performance of 0.8 microns of wavefront error can be expected during the maintenance function based on specified nominal sensor noises, actuator accuracies, and system environments. A performance of less than 0.3 microns rms can be expected, based on advanced components.

  14. 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.

  15. 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.

  16. 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.

  17. 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. PMID:25361349

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

    NASA Astrophysics Data System (ADS)

    Zhai, Tianrui; Chen, Li; Li, Songtao; Hu, Yujie; Wang, Yimeng; Wang, Li; Zhang, Xinping

    2016-01-01

    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.

  19. Adaptive optics at the PHELIX laser

    NASA Astrophysics Data System (ADS)

    Heuck, Hans-Martin; Wittrock, Ulrich; Fils, Jérôme; Borneis, Stefan; Witte, Klaus; Eisenbart, Udo; Javorkova, Dasa; Bagnoud, Vincent; Götte, Stefan; Tauschwitz, Andreas; Onkels, Eckehard

    2007-05-01

    GSI Darmstadt currently builds a high-energy petawatt Nd:glass laser system, called PHELIX (Petawatt High-Energy Laser for Heavy-Ion Experiments). PHELIX will offer the world-wide unique combination of a high current, high-energy heavy-ion beam with an intense laser beam. Aberrations due to the beam transport and due to the amplification process limit the focusability and the intensity at the target. We have investigated the aberrations of the different amplification stages. The pre-amplifier stage consists of three rod-amplifiers which cause mainly defocus, but also a small part of coma and astigmatism. The main amplifier consists of five disk amplifiers with a clear aperture of 315 mm. These large disk-amplifiers cause pump-shot aberrations which occur instantly. After a shot, the disk amplifiers need a cooling time of several hours to relax to their initial state. This limits the repetition rate and causes long-term aberrations. We will present first measurements of the pump-shot and long-term aberrations caused by the pre- and the main amplifier in a single-pass configuration. In this context, we will present the adaptive optics system which is implemented in the PHELIX beam line and discuss its capability to compensate for the pump-shot and long-term aberrations.

  20. Ultrafast optical pulse interactions in active disordered condensed matter

    NASA Astrophysics Data System (ADS)

    Siddique, Masood

    2005-07-01

    The goal of this research is to better understand the basic physics that governs the behavior of short-pulsed light propagating in scattering media where either the host medium or the scattering particles exhibit emission or absorption interact with the incident light in form of absorption or stimulated emission. The temporal and spectral dynamics from the interactions of optically active disordered-media with ultrashort optical pulses is the focus of the research performed in this thesis. The interaction processes studied are optical gain, spectral narrowing, fluorescence and pulse lifetime reduction and transport of ultrashort optical pulses in disordered media containing optically active discrete scattering particles. Linear and nonlinear effects are presented where the propagation of picosecond and femtosecond laser pulses in active disordered media is measured experimentally and compared with the theories of Boltzmann radiative transport and diffusive propagation of radiation in disordered media. Active media can be involved in optical processes in disordered media where either the propagation of optical radiation can result in gain or absorption upon optical excitation. A study of optical scattering in non-discrete media such as the biological heterogeneously-continuous scattering tissues is carried out as well. Lasing in random media is one of the outcomes of these results. The optical gain of optically excited active media is divided into clear subdivisions of Amplified Spontaneous Emission, Stimulated Emission and Laser Emission by characterizing them by their temporal and spectral emission.

  1. Organic semiconductor lasers as integrated light sources for optical sensor systems

    NASA Astrophysics Data System (ADS)

    Punke, Martin; Woggon, Thomas; Stroisch, Marc; Ebenhoch, Bernd; Geyer, Ulf; Karnutsch, Christian; Gerken, Martina; Lemmer, Uli; Bruendel, Mathias; Wang, Jing; Weimann, Thomas

    2007-09-01

    We demonstrate the feasibility of organic semiconductor lasers as light sources for lab-on-a-chip systems. These lasers are based on a 1D- or 2D-photonic crystal resonator structure providing optical feedback in the active laser material that is deposited on top, e.g. aluminum tris(8-hydroxyquinoline) (Alq 3) doped with the laser dye 4-dicyanomethylene-2-methyl-6-(p-dimethylaminostyryl)-4H-pyran (DCM). We investigated different fabrication methods for the resonator structures, like thermal nanoimprint, UV nanoimprint, and laser interference lithography. Different substrate materials commonly used in lab-on-a-chip systems, e.g. PMMA, Topas, and Ormocer were deployed. By changing the distributed feedback grating periodicity, we demonstrate a tuning range for a single material system of more than 120 nm. The investigated organic semiconductor lasers are optically pumped. External optical pumping provides a feasible way for one-time-use chips. Our recent success of pumping organic lasers with a low-cost laser diode also renders hand-held systems possible. As a further step towards the integration of organic lasers in sensor systems, we demonstrate the coupling of an organic laser into polymeric waveguides which can be combined with microfluidic channels. The integrated organic lasers and the waveguides are both fabricated on the same polished PMMA substrate using thermal nanoimprint lithography and deep-UV modification, respectively. We could demonstrate the guiding of the laser light in single-mode waveguides.

  2. 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.

  3. Hole drilling with fiber-optically delivered visible lasers

    SciTech Connect

    Kautz, D.D.; Berzins, L.V.; Dragon, E.P.

    1994-12-31

    The use of lasers for high-speed drilling of holes in materials is well documented. To allow easier use of lasers in manufacturing processes, fiber-optically delivered beams are preferable to the use of conventional optics. Lawrence Livermore National Laboratory (LLNL) has adapted fiber-optic technology to its visible light, copper vapor lasers for use in hole drilling studies. Visible lasers afford better coupling of light to the workpiece and when fiber-optically delivered, allow high quality holes to be drilled in difficult accessibility areas and with easier setup. A fiber-optic delivery system was attached to the presently hard-optic copper vapor laser system. This system consisted of a 0.6 mm (0.024 in.) fiber that was then telescoped and refocused by a hard optics package at the workstation end of the fiber. The optics package produced a 0.2 mm (0.008 in.) focused spot size at the workpiece. This system was then run down to a 3-axis CNC machining table to allow part movement for these studies. The fiber-optically delivered light was found to work extremely well for drilling small diameter holes. In summary, it was found that fiber-optically delivered, visible laser beams have several advantages in drilling over those same beams delivered through conventional hard optics. These include much easier setup, reduced system maintenance, and typically higher hole quality.

  4. OPTOGELs: optically active xerogels

    NASA Astrophysics Data System (ADS)

    Canva, Michael; Georges, Patrick M.; Brun, Alain; Chaput, Frederic; Devreux, Francois; Boilot, Jean-Pierre

    1992-12-01

    Using the sol-gel process, we synthesized zirconia/silica matrices doped with different organic dyes (rhodamine 640, ...). These samples were used to perform optical Kerr effect experiments with sequences of ultrashort light pulses (100 fs, 620 nm, 1 (mu) J focused on 50 micrometers diameter) to induce refractive index changes. A permanent birefringence around 7 X 10-5 was obtained. By changing the direction of the polarization of the excitation pulses, we were able to locally control the directions of the neutral axes. We thus demonstrated the possibility of using this media as an all optical memory matrix and such doped xerogels will subsequently be referred to as OPTOGELS. We interpret our results as the possibility of locally controlling the orientation of the doping molecules encaged in the solid host matrix. The memory effect is probably due to links of hydrogen bond type between the organic molecules and the pore surface which prevent thermal reorientation. The electric field of the optical excitation pulses exerts a torque on the molecules. If this torque is greater than the energy linking the molecules to the pore surface, the molecules are temporarily released and aligned in the direction of the pulse polarization. Based on this interpretation, we have developed a model to explain the evolution of the birefringence as a function of the number of excitation pulses.

  5. A novel optical gating method for laser gated imaging

    NASA Astrophysics Data System (ADS)

    Ginat, Ran; Schneider, Ron; Zohar, Eyal; Nesher, Ofer

    2013-06-01

    For the past 15 years, Elbit Systems is developing time-resolved active laser-gated imaging (LGI) systems for various applications. Traditional LGI systems are based on high sensitive gated sensors, synchronized to pulsed laser sources. Elbit propriety multi-pulse per frame method, which is being implemented in LGI systems, improves significantly the imaging quality. A significant characteristic of the LGI is its ability to penetrate a disturbing media, such as rain, haze and some fog types. Current LGI systems are based on image intensifier (II) sensors, limiting the system in spectral response, image quality, reliability and cost. A novel propriety optical gating module was developed in Elbit, untying the dependency of LGI system on II. The optical gating module is not bounded to the radiance wavelength and positioned between the system optics and the sensor. This optical gating method supports the use of conventional solid state sensors. By selecting the appropriate solid state sensor, the new LGI systems can operate at any desired wavelength. In this paper we present the new gating method characteristics, performance and its advantages over the II gating method. The use of the gated imaging systems is described in a variety of applications, including results from latest field experiments.

  6. 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. PMID:15813279

  7. 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.

  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. Biological research by optically pumped far infrared lasers

    NASA Astrophysics Data System (ADS)

    Zhengyu, Mi

    1989-05-01

    The FIR breeding for paddy rice, black bean and wheat, the chlorophyll mutation of paddy rice induced by optically pumped FIR laser, etc., are presented. The results of SDS electrophoresis analysis of soluble proteins of Drosophita melanrgaster irradiated by optically pumped FIR laser are described and discussed.

  10. Laser-induced microwave generation with nonlinear optical crystals

    NASA Astrophysics Data System (ADS)

    Borghesani, Francesco; Braggio, Caterina; Carugno, Giovanni; Della Valle, Federico; Ruoso, Giuseppe

    2014-05-01

    We report about a novel technique to generate microwave radiation by the irradiation of a nonlinear optical crystal with uniformly spaced, ultrashort optical pulses delivered by a mode-locked laser. We study systematically the laser polarization and intensity dependence of the microwave signal to conclusively show that it is a nonlinear phenomenon and that it originates from optical rectification. The measurements have been conducted using KTP, LBO and ZnSe crystals. The observed pulsed microwave signals are harmonically related to the laser pulses repetition rate, a feature that can be exploited to develop an innovative ultrafast laser detector.

  11. 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.

  12. Optical velocimeters for moving surfaces using gas and semiconductor lasers

    NASA Astrophysics Data System (ADS)

    Belousov, P. Ya.; Dubnistshev, Yu. N.; Meledin, V. G.

    1990-10-01

    A differential arrangement using a laser for the measurement of the velocity of moving surfaces is discussed. Configurations of optical velocimeters with diffraction beam-splitters are shown not to be critical on the wavelength stability of a semiconductor laser. Laser meters measuring the velocity and length of rolled stock have been built on the basis of the devices considered.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. The Recovery of Optical Quality after Laser Vision Correction

    PubMed Central

    Jung, Hyeong-Gi

    2013-01-01

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

  19. Pulse-stretched Alexandrite laser for improved optical fiber reliability for laser lithotripsy

    NASA Astrophysics Data System (ADS)

    Simons, David; Koschmann, Eric C.

    1992-06-01

    Clinical data shows that short pulse duration lasers used in laser induced shock wave lithotripsy severely damage optical fibers on both the proximal and distal ends which is unsuitable for clinical use. An Alexandrite laser system has been developed that uses dynamic pulse stretching of the Q-switched laser pulse and improved optical fiber coupling to eliminate the fiber damage. The method of pulse stretching presented controls the laser output pulse energy from 50 to 150 millijoules and temporal shape from 0.5 to 1.5 microseconds. This yields effective fragmentation of calculi without damage to the optical fiber.

  20. 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.

  1. Low-threshold terahertz molecular laser optically pumped by a quantum cascade laser

    NASA Astrophysics Data System (ADS)

    Pagies, A.; Ducournau, G.; Lampin, J.-F.

    2016-06-01

    We demonstrate a low-threshold, compact, room temperature, and continuous-wave terahertz molecular laser optically pumped by a mid-infrared quantum cascade laser. These characteristics are obtained, thanks to large dipole transitions of the active medium: NH3 (ammonia) in gas state. The low-power (<60 mW) laser pumping excites the molecules, thanks to intense mid-infrared transitions around 10.3 μm. The molecules de-excite by stimulated emission on pure inversion "umbrella-mode" quantum transitions allowed by the tunnel effect. The tunability of the quantum cascade laser gives access to several pure inversion transitions with different rotation states: we demonstrate the continuous-wave generation of ten laser lines around 1 THz. At 1.07 THz, we measure a power of 34 μW with a very low-threshold of 2 mW and a high differential efficiency of 0.82 mW/W. The spectrum was measured showing that the linewidth is lower than 1 MHz. To our knowledge, this is the first THz molecular laser pumped by a solid-state source and this result opens the way for compact, simple, and efficient THz source at room temperature for imaging applications.

  2. 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.

  3. 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

  4. Nd:GGG disk laser with multipoint spatially periodic optical pumping

    NASA Astrophysics Data System (ADS)

    Guryev, D. A.; Nikolaev, D. A.; Tsvetkov, V. B.

    2016-04-01

    The results of the study of the output laser beam spatial characteristics of the Nd:Gd3Ga5O12 (Nd:GGG) disk laser with multipoint spatially periodic diode-pumping are presented. The presence of the optical coupling between the TEM00 lasing channels is demonstrated. The phase-locking of channels was realized due to partial overlapping of laser beams inside the pumped areas of the active element disk.

  5. 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

  6. Laser-induced heating in optical traps.

    PubMed

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

    2003-02-01

    In an optical tweezers experiment intense laser light is tightly focused to intensities of MW/cm(2) 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

  7. Laser Scanning-Assisted Tip-Enhanced Optical Microscopy for Robust Optical Nanospectroscopy.

    PubMed

    Yano, Taka-Aki; Tsuchimoto, Yuta; Mochizuki, Masahito; Hayashi, Tomohiro; Hara, Masahiko

    2016-07-01

    Laser-scanning-assisted tip-enhanced optical microscopy was developed for robust optical nanospectroscopy. The laser-scanning system was utilized to automatically set and keep the center of a tight laser-focusing spot in the proximity of a metallic tip with around 10 nm precision. This enabled us to efficiently and stably induce plasmon-coupled field enhancement at the apex of the metallic probe tip. The laser-scanning technique was also applied to tracking and compensating the thermal drift of the metallic tip in the spot. This technique is usable for long-term tip-enhanced optical spectroscopy without any optical degradation. PMID:27412187

  8. Optical limiting of short laser pulses

    SciTech Connect

    Liu, J.-C.; Wang, C.-K.; Gel'mukhanov, Faris

    2007-11-15

    The dynamics of pulse propagation accompanied by harmonic generation, stimulated Raman scattering, amplified spontaneous emission, and superfluorescence is studied near the two-photon resonance. We explore the optical limiting of intense and short laser pulses. The numerical solutions of the coupled Bloch and Maxwell's equations for the 4,4{sup '}-bis(dimethylamino) stilbene molecule are compared with the two-photon area theorem. It is shown that the area theorem explains qualitatively the major dynamical properties of pulse propagation even if the propagation is accompanied by the generation of new fields. In agreement with the area theorem, we see that the conventional dependence of the transmittance on the propagation depth is not valid for intense pulses.

  9. Ultrafast laser-induced changes in optical properties of semiconductors

    SciTech Connect

    Chirila, C. C.; Lim, Freda C. H.; Gavaza, M. G.

    2012-04-01

    We study the effect of laser radiation on optical properties of semiconductors of industrial interest. The material is pumped with a laser of chosen central frequency, for which the absorption is maximal, thus inducing electron dynamics, which modifies the optical properties. By using an improved theoretical model, we study ultrafast dynamic changes in the refraction index and reflectivity corresponding to a wide frequency-interval of probing radiation and identify that interval where these optical changes are most significant.

  10. Integrated Optical Memory Based on Laser-Written Waveguides

    NASA Astrophysics Data System (ADS)

    Corrielli, Giacomo; Seri, Alessandro; Mazzera, Margherita; Osellame, Roberto; de Riedmatten, Hugues

    2016-05-01

    We propose and demonstrate a physical platform for the realization of integrated photonic memories based on laser-written waveguides in rare-earth-doped crystals. Using femtosecond-laser micromachining, we fabricate waveguides in Pr3 +∶Y2SiO5 crystal. We demonstrate that the waveguide inscription does not affect the coherence properties of the material and that the light confinement in the waveguide increases the interaction with the active ions by a factor of 6. We also demonstrate that analogous to the bulk crystals, we can operate the optical pumping protocols necessary to prepare the population in atomic-frequency combs that we use to demonstrate light storage in excited and spin states of the Praseodymium ions. Our results represent a realization of laser-written waveguides in a Pr3 +∶Y2SiO5 crystal and an implementation of an integrated on-demand spin-wave optical memory. They open perspectives for integrated quantum memories.

  11. 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.

  12. All-Optical Laser-Wakefield Electron Injector

    SciTech Connect

    Umstadter, Donald P.

    2003-07-01

    Demonstrated the principle of optical control of laser accelerators, namely, that one laser pulse could modify the properties (e.g., emittance and electron number) of an electron beam accelerated by a separate but synchronized laser pulse. Another recent highlight was that, using our new 30-fs 10-TW laser system, we accelerated with a laser accelerator an electron beam with a record low divergence (0.2 degrees). This is more than 100 times lower than the 30-degree divergence that was reported recently by a French group using a laser with similar parameters.

  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. 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.

  15. 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.

  16. 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.

  17. Matter-wave analog of an optical random laser

    SciTech Connect

    Plodzien, Marcin; Sacha, Krzysztof

    2011-08-15

    The accumulation of atoms in the lowest energy level of a trap and the subsequent out coupling of these atoms is a realization of a matter-wave analog of a conventional optical laser. Optical random lasers require materials that provide optical gain but, contrary to conventional lasers, the modes are determined by multiple scattering and not a cavity. We show that a Bose-Einstein condensate can be loaded in a spatially correlated disorder potential prepared in such a way that the Anderson localization phenomenon operates as a bandpass filter. A multiple scattering process selects atoms with certain momenta and determines laser modes which represents a matter-wave analog of an optical random laser.

  18. Optically Probed Laser-Induced Field-Free Molecular Alignment

    NASA Astrophysics Data System (ADS)

    Faucher, O.; Lavorel, B.; Hertz, E.; Chaussard, F.

    Molecular alignment induced by laser fields has been investigated in research laboratories for over two decades. It led to a better understanding of the fundamental processes at play in the interaction of strong laser fields with molecules, and also provided significant contributions to the fields of high harmonic generation, laser spectroscopy, and laser filamentation. In this chapter, we discuss molecular alignment produced under field-free conditions, as resulting from the interaction of a laser pulse of duration shorter than the rotational period of the molecule. The experimental results presented will be confined to the optically probed alignment of linear as well as asymmetric top molecules. Special care will be taken to describe and compare various optical methods that can be employed to characterize laser-induced molecular alignment. Promising applications of optically probed molecular alignment will be also demonstrated.

  19. 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.

  20. Laser activated MTOS microwave device

    NASA Technical Reports Server (NTRS)

    Maserjian, J. (Inventor)

    1985-01-01

    A light-activated semiconductor device usable as an optoelectronic switch, pulse generator or optical detector is provided. A semiconductor device is disclosed which provides back-to-back metal-thin oxide-silicon (MTOS) capacitors. Each capacitor includes a thin, light-absorptive aluminum electrode which overlies a thin oxide layer and a lightly doped region implanted in an intrinsic silicon substrate.

  1. 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.

  2. Advanced metaheuristic algorithms for laser optimization in optical accelerator technologies

    NASA Astrophysics Data System (ADS)

    Tomizawa, Hiromitsu

    2011-10-01

    Lasers are among the most important experimental tools for user facilities, including synchrotron radiation and free electron lasers (FEL). In the synchrotron radiation field, lasers are widely used for experiments with Pump-Probe techniques. Especially for X-ray-FELs, lasers play important roles as seed light sources or photocathode-illuminating light sources to generate a high-brightness electron bunch. For future accelerators, laser-based techonologies such as electro-optic (EO) sampling to measure ultra-short electron bunches and optical-fiber-based femtosecond timing systems have been intensively developed in the last decade. Therefore, controls and optimizations of laser pulse characteristics are strongly required for many kinds of experiments and improvement of accelerator systems. However, people believe that lasers should be tuned and customized for each requirement manually by experts. This makes it difficult for laser systems to be part of the common accelerator infrastructure. Automatic laser tuning requires sophisticated algorithms, and the metaheuristic algorithm is one of the best solutions. The metaheuristic laser tuning system is expected to reduce the human effort and time required for laser preparations. I have shown some successful results on a metaheuristic algorithm based on a genetic algorithm to optimize spatial (transverse) laser profiles, and a hill-climbing method extended with a fuzzy set theory to choose one of the best laser alignments automatically for each machine requirement.

  3. 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

  4. Optical laser systems at the Linac Coherent Light Source

    DOE PAGESBeta

    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; et al

    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.

  5. Laser-scanning optical-resolution photoacoustic microscopy.

    PubMed

    Xie, Zhixing; Jiao, Shuliang; Zhang, Hao F; Puliafito, Carmen A

    2009-06-15

    We have developed a laser-scanning optical-resolution photoacoustic microscopy method that can potentially fuse with existing optical microscopic imaging modalities. To acquire an image, the ultrasonic transducer is kept stationary during data acquisition, and only the laser light is raster scanned by an x-y galvanometer scanner. A lateral resolution of 7.8 microm and a circular field of view with a diameter of 6 mm were achieved in an optically clear medium. Using a laser system working at a pulse repetition rate of 1,024 Hz, the data acquisition time for an image consisting of 256 x 256 pixels was less than 2 min. PMID:19529698

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. An optically-triggered semiconductor switch for high power laser beams

    SciTech Connect

    Chow, Weng W.; Warren, M.E.

    1995-04-01

    The work involves research leading to an optically triggered switch for a high power laser pulse. The switch uses a semiconductor heterostructure whose optical properties are modified by a low power laser trigger such as a laser diode. Potential applications include optical control of pulsed power systems, control of medical lasers and implementation of security features in optical warhead architectures.

  11. 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.

  12. 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.

  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. Optical system design and integration of the Mars Observer Laser Altimeter.

    PubMed

    Ramos-Izquierdo, L; Bufton, J L; Hayes, P

    1994-01-20

    The Mars Observer Laser Altimeter, developed for flight on the Mars Observer spacecraft payload in September 1992, is designed to measure the topography of the Martian surface over a 2-year period from a 400-km mapping orbit. A 40 mJ pulse diode-pumped laser together with a 0.5-m-diameter beryllium telescope and a silicon avalanche photodiode are the principal optical subassemblies of this active remote-sensing instrument. Optical design rationale and measured optical performances during assembly and integration are presented. PMID:20862020

  15. Optical activity of BL Lacertae

    NASA Astrophysics Data System (ADS)

    Larionov, V.; Blinov, D.; Konstantinova, T.

    2012-04-01

    We perform optical photometric and R-band polarimetric monitoring of BL Lac using 70-cm AZT-8 (CrAO, Ukraine) and 0.4-m LX-200 (St.Petersburg, Russia) telescopes, as a part of GASP project. As reported in Atel#4028, this blazar was found by Fermi LAT in active state on 2012 April 9. Our data show that a sharp optical maximum was reached on the date 2012-04-08UT02:20, R=13.10, while on 2012-04-11UT01:30 R=13.40.

  16. 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.

  17. Optical coatings for laser fusion applications

    SciTech Connect

    Lowdermilk, W.H.; Milam, D.; Rainer, F.

    1980-04-24

    Lasers for fusion experiments use thin-film dielectric coatings for reflecting, antireflecting and polarizing surface elements. Coatings are most important to the Nd:glass laser application. The most important requirements of these coatings are accuracy of the average value of reflectance and transmission, uniformity of amplitude and phase front of the reflected or transmitted light, and laser damage threshold. Damage resistance strongly affects the laser's design and performance. The success of advanced lasers for future experiments and for reactor applications requires significant developments in damage resistant coatings for ultraviolet laser radiation.

  18. 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.

  19. 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.

  20. Dye laser studies using zig-zag optical cavity

    SciTech Connect

    Klimek, D.E.; Mandl, A.E.; Willman, B. )

    1994-06-01

    The authors report a substantial advance in dye laser performance using a zig-zag optical cavity. This configuration drastically reduces the effects of intrapulse medium disturbances due to acoustics and thermal lensing on pulse duration, beam quality, and extraction efficiency. Laser outputs of up to 2 J were observed from Coumarin-498 dye pumped by a KrF excimer laser. The dye laser output faithfully replicates the flat-top KrF laser pump pulse over the entire 1.7-[mu]s pulse duration. An intrinsic laser photon conversion efficiency (Photons[sub in]/Photons[sub absorbed]) of 44% was measured. When unstable resonator optics were used, beam qualities of about 2 XDL were measured.

  1. 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.

  2. 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.

  3. Active Vibration Control For Lasers And Spacecraft

    NASA Astrophysics Data System (ADS)

    Pearson, Jerome

    1983-12-01

    The Active Control of Space Structures (ACOSS) program of the Defense Advanced Research Projects Agency has identified problems in active vibration control of structural modes in extremely flexible space structures and in precisely pointed optics. The Air Force Wright Aeronautical Laboratories programs are an outgrowth of the ACOSS program. They are aimed at the problems of sensors, actuators, and their dynamic interactions with the structure to be controlled, and at the problem of system identification by one-g laboratory experiments. The VCOSS-1 and VCOSS-2 programs (Vibration Control of Space Structures) address the dynamic interactions of the sensor-actuator-structure; the Benchless Laser program and the Airborne Laser Mirror-Control program address the active control of HEL mirrors; the Experimental Modal Analysis and Component Synthesis and the Large Space Structure Dynamics programs address the problems of system identification and testing. Closer coordination with NASA and DARPA is being sought in support of on-orbit dynamic testing using the Space Shuttle and in the development of a national facility for one-g dynamics testing of large space structures.

  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. Wide baseline optical interferometry with Laser Guide Stars

    SciTech Connect

    Gavel, D. T., LLNL

    1998-03-01

    Laser guide stars have been used successfully as a reference source for adaptive optics systems. We present a possible method for utilizing laser beacons as sources for interferometric phasing. The technique would extend the sky coverage for wide baseline interferometers and allow interferometric measurement and imaging of dim objects.

  6. Innovative optics for shaping and focusing industrial CO2 lasers

    NASA Astrophysics Data System (ADS)

    Danielewicz, Edward J.; Sherman, Glenn H.

    1989-03-01

    Applications of diamond-turned axicons for high power CO2 lasers are reviewed. The use of transmissive and reflective axicons in laser applications and the use of faceted optics for shaping and directing laser light are discussed. Diamond-turned ZnSe lenses are compared with conventional plano-convex and meniscus lenses. Results are presented from cutting and welding plastics and metals, noting the advantages of diamond-turned focusing elements.

  7. 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.

  8. Femtosecond-precision synchronization of the pump-probe optical laser for user experiments at FLASH

    NASA Astrophysics Data System (ADS)

    Schulz, S.; Czwalinna, M. K.; Felber, M.; Predki, P.; Schefer, S.; Schlarb, H.; Wegner, U.

    2013-05-01

    In this paper, we present the long-term stable synchronization of the FLASH pump-probe Ti:sapphire oscillator to an optical reference with sub-10 fs (rms) timing jitter employing a balanced optical cross-correlator. The reference pulse train, transmitted over an actively transit time-stabilized 500m long fiber link, is generated by the FLASH master laser oscillator. This laser also provides the reference for several electron bunch arrival time monitors with sub-10 fs resolution, which in turn enables a longitudinal feedback reducing the electron bunch arrival time jitter to below 25 fs (rms). Combining the precise synchronization of the laser and the longitudinal accelerator feedback enabled a proof-of-principle pump-probe experiment at FLASH, ultimately showing a significant reduction of the timing jitter between the optical laser and the XUV pulses generated by the FEL, compared to the present standard operation.

  9. An active alignment method for post launch co-alignment of laser beam combiner systems

    NASA Technical Reports Server (NTRS)

    Yu, A. W.; Green, J. W.; Maynard, W. L.; Minott, P. O.; Krainak, M. A.

    1992-01-01

    A laser transmitter for high bandwidth geosynchronous satellite communications is described. High optical power is achieved by combining semiconductor laser diodes. An active alignment scheme is proposed for achieving the +/- 20 microrad post launch multiple laser angular co-alignment requirement.

  10. 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.