WorldWideScience

Sample records for nm frequency doubled

  1. Laser cooling of beryllium ions using a frequency-doubled 626 nm diode laser

    NARCIS (Netherlands)

    Cozijn, F.M.J.; Biesheuvel, J.; Flores, A.S.; Ubachs, W.M.G.; Blume, G.; Wicht, A.; Paschke, K.; Erbert, G.; Koelemeij, J.C.J.

    2013-01-01

    We demonstrate laser cooling of trapped beryllium ions at 313 nm using a frequency-doubled extended cavity diode laser operated at 626 nm, obtained by cooling a ridge waveguide diode laser chip to -31°C. Up to 32 mW of narrowband 626 nm laser radiation is obtained. After passage through an optical

  2. Laser cooling of beryllium ions using a frequency-doubled 626 nm diode laser.

    Science.gov (United States)

    Cozijn, F M J; Biesheuvel, J; Flores, A S; Ubachs, W; Blume, G; Wicht, A; Paschke, K; Erbert, G; Koelemeij, J C J

    2013-07-01

    We demonstrate laser cooling of trapped beryllium ions at 313 nm using a frequency-doubled extended cavity diode laser operated at 626 nm, obtained by cooling a ridge waveguide diode laser chip to -31°C. Up to 32 mW of narrowband 626 nm laser radiation is obtained. After passage through an optical isolator and beam shaping optics, 14 mW of 626 nm power remains of which 70% is coupled into an external enhancement cavity containing a nonlinear crystal for second-harmonic generation. We produce up to 35 μW of 313 nm radiation, which is subsequently used to laser cool and detect 6×10(2) beryllium ions, stored in a linear Paul trap, to a temperature of about 10 mK, as evidenced by the formation of Coulomb crystals. Our setup offers a simple and affordable alternative for Doppler cooling, optical pumping, and detection to presently used laser systems.

  3. Clinical analysis of 532nm frequency-doubled laser in treating retinal holes of 78 eyes

    Directory of Open Access Journals (Sweden)

    Heng Li

    2013-09-01

    Full Text Available AIM: To evaluate the clinical effect of photocoagulation with 532nm frequency-doubled laser in patients with retinal hole.METHODS: Seventy-two cases(78 eyeswith retinal holes were treated with 532nm frequency-doubled laser. All the eyes were divided according to the quadrants of location of retinal holes and the size of retinal hole and existence of local retinal detachment accompanying retinal holes. Statistical analysis was made on these data.RESULTS: 1The retinal holes were located in the upper quadrants of retina in 44 eyes and there were also retinal holes located in the lower quadrants of retina in 31 eyes(there were 3 eyes with retinal holes both located in the upper and lower quadrants of retina, which were not included in control group. The difference of photocoagulation effect between the two groups was statistically significant. 2The retinal holes diameter ≤2 papilla diameter(PDwere present in 37 eyes, the holes diameter of retina >2PD were seen in 41 eyes, the difference of photocoagulation effect between the two groups was statistically significant. 3Retinal holes without local retinal detachment were observed in 45 eyes, retinal holes with local retinal detachment were seen in 33 eyes, the difference of photocoagulation effect between the two groups was statistically significant.CONCLUSION:Photocoagulation with 532nm frequency-doubled laser is effective and safe to treat retinal holes. The effect is better in patients with retinal holes in the upper quadrants and with the retinal holes diameter ≤2PD and without local retinal detachment.

  4. Efficient generation of 3.5W laser light at 515nm by frequency doubling a single-frequency high power DBR tapered diode laser

    DEFF Research Database (Denmark)

    Jensen, Ole Bjarlin; Hansen, Anders Kragh; Müller, André

    2017-01-01

    More than 3.5 W of green light at 515 nm is generated by frequency doubling a single-frequency high power DBR tapered diode laser. The frequency doubling is performed in a cascade of PPMgLN and PPMgSLT crystals in order to reach high power and avoid thermal effects present in PPMgLN at high power....... The green light is diffraction limited (M2

  5. LD-pumped Nd:YVO sub 4 frequency-doubled by CPM LBO laser at 671 nm

    CERN Document Server

    Zheng Quan; Qian Long Sheng; Zhao Ling

    2001-01-01

    A design of LD-pumped high efficient Nd:YVO sub 4 /LBO red laser is reported. Using critical phase-matching LBO for the first time, 671 nm red laser is obtained by 1.342 mu m intracavity frequency doubling. With 800 mW incident pump laser, 52 mW and 97 mW TEM00 mode red laser output are obtained by II-typed and I-typed LBO. The optical-to-optical conversions are up to 6.5% and 12.1% respectively

  6. CW frequency doubling of 1029 nm radiation using single pass bulk and waveguide PPLN crystals

    Czech Academy of Sciences Publication Activity Database

    Chiodo, N.; Du Burck, F.; Hrabina, Jan; Candela, Y.; Wallerand, J. P.; Acef, O.

    2013-01-01

    Roč. 311, 15 January (2013), s. 239-244 ISSN 0030-4018 R&D Projects: GA ČR GPP102/11/P820 Institutional support: RVO:68081731 Keywords : IR laser * second harmonic generation * waveguide and bulk crystals * periodically poled lithium niobate * 1029 nm wavelength Subject RIV: BH - Optics, Masers, Lasers Impact factor: 1.542, year: 2013

  7. 303 nm continuous wave ultraviolet laser generated by intracavity frequency-doubling of diode-pumped Pr3+:LiYF4 laser

    Science.gov (United States)

    Zhu, Pengfei; Zhang, Chaomin; Zhu, Kun; Ping, Yunxia; Song, Pei; Sun, Xiaohui; Wang, Fuxin; Yao, Yi

    2018-03-01

    We demonstrate an efficient and compact ultraviolet laser at 303 nm generated by intracavity frequency doubling of a continuous wave (CW) laser diode-pumped Pr3+:YLiF4 laser at 607 nm. A cesium lithium borate (CLBO) crystal, cut for critical type I phase matching at room temperature, is used for second-harmonic generation (SHG) of the fundamental laser. By using an InGaN laser diode array emitting at 444.3 nm with a maximum incident power of 10 W, as high as 68 mW of CW output power at 303 nm is achieved. The output power stability in 4 h is better than 2.85%. To the best of our knowledge, this is high efficient UV laser generated by frequency doubling of an InGaN laser diode array pumped Pr3+:YLiF4 laser.

  8. Quasi-continuous-wave 589-nm radiation based on intracavity frequency-doubled Nd:GGG/BaWO4 Raman laser

    Science.gov (United States)

    Liu, Yang; Liu, Zhaojun; Cong, Zhenhua; Men, Shaojie; Rao, Han; Xia, Jinbao; Zhang, Sasa; Zhang, Huaijin

    2016-07-01

    Quasi-continuous-wave (QCW) 589-nm radiation was realized based on a frequency-doubled crystalline Raman laser. The fundamental wave with macro-micro-pulse trains was generated from an acousto-optically Q-switched QCW diode side-pumped Nd:GGG laser. Intracavity Raman conversion was accomplished by a BaWO4 crystal and the second harmonic generation was finished by a KTP crystal. Under a pumping power of 126.0 W with a macro-pulse frequency of 300 Hz and duration of 300 μs, the maximum 589 nm output power of 4.2 W was obtained at a micro-pulse frequency of 33.3 kHz. The micro-pulse width was 13.6 ns.

  9. 2.1-watts intracavity-frequency-doubled all-solid-state light source at 671 nm for laser cooling of lithium.

    Science.gov (United States)

    Eismann, U; Bergschneider, A; Sievers, F; Kretzschmar, N; Salomon, C; Chevy, F

    2013-04-08

    We present an all-solid-state laser source emitting up to 2.1 W of single-frequency light at 671 nm developed for laser cooling of lithium atoms. It is based on a diode-pumped, neodymium-doped orthovanadate (Nd:YVO(4)) ring laser operating at 1342 nm. Optimization of the thermal management in the gain medium results in a maximum multi-frequency output power of 2.5 W at the fundamental wavelength. We develop a simple theory for the efficient implementation of intracavity second harmonic generation, and its application to our system allows us to obtain nonlinear conversion efficiencies of up to 88%. Single-mode operation and tuning is established by adding an etalon to the resonator. The second-harmonic wavelength can be tuned over 0.5 nm, and mode-hop-free scanning over more than 6 GHz is demonstrated, corresponding to around ten times the laser cavity free spectral range. The output frequency can be locked with respect to the lithium D-line transitions for atomic physics applications. Furthermore, we observe parametric Kerr-lens mode-locking when detuning the phase-matching temperature sufficiently far from the optimum value.

  10. Generation of high-energy sub-20 fs pulses tunable in the 250-310 nm region by frequency doubling of a high-power noncollinear optical parametric amplifier.

    Science.gov (United States)

    Beutler, Marcus; Ghotbi, Masood; Noack, Frank; Brida, Daniele; Manzoni, Cristian; Cerullo, Giulio

    2009-03-15

    We report on the generation of powerful sub-20 fs deep UV pulses with 10 microJ level energy and broadly tunable in the 250-310 nm range. These pulses are produced by frequency doubling a high-power noncollinear optical parametric amplifier and compressed by a pair of MgF2 prisms to an almost transform-limited duration. Our results provide a power scaling by an order of magnitude with respect to previous works.

  11. Frequency doubling crystals

    Science.gov (United States)

    Wang, Francis; Velsko, Stephan P.

    1989-01-01

    A systematic approach to the production of frequency conversion crystals is described in which a chiral molecule has attached to it a "harmonic generating unit" which contributes to the noncentrosymmetry of the molecule. Certain preferred embodiments of such harmonic generating units include carboxylate, guanadyly and imidazolyl units. Certain preferred crystals include L-arginine fluoride, deuterated L-arginine fluoride, L-arginine chloride monohydrate, L-arginine acetate, dithallium tartrate, ammonium N-acetyl valine, N-acetyl tyrosine and N-acetyl hydroxyproline. Chemical modifications of the chiral molecule, such as deuteration, halogenation and controlled counterion substitution are available to adapt the dispersive properties of a crystal in a particular wavelength region.

  12. A novel double patterning approach for 30nm dense holes

    Science.gov (United States)

    Hsu, Dennis Shu-Hao; Wang, Walter; Hsieh, Wei-Hsien; Huang, Chun-Yen; Wu, Wen-Bin; Shih, Chiang-Lin; Shih, Steven

    2011-04-01

    Double Patterning Technology (DPT) was commonly accepted as the major workhorse beyond water immersion lithography for sub-38nm half-pitch line patterning before the EUV production. For dense hole patterning, classical DPT employs self-aligned spacer deposition and uses the intersection of horizontal and vertical lines to define the desired hole patterns. However, the increase in manufacturing cost and process complexity is tremendous. Several innovative approaches have been proposed and experimented to address the manufacturing and technical challenges. A novel process of double patterned pillars combined image reverse will be proposed for the realization of low cost dense holes in 30nm node DRAM. The nature of pillar formation lithography provides much better optical contrast compared to the counterpart hole patterning with similar CD requirements. By the utilization of a reliable freezing process, double patterned pillars can be readily implemented. A novel image reverse process at the last stage defines the hole patterns with high fidelity. In this paper, several freezing processes for the construction of the double patterned pillars were tested and compared, and 30nm double patterning pillars were demonstrated successfully. A variety of different image reverse processes will be investigated and discussed for their pros and cons. An economic approach with the optimized lithography performance will be proposed for the application of 30nm DRAM node.

  13. 100-nm gate lithography for double-gate transistors

    Science.gov (United States)

    Krasnoperova, Azalia A.; Zhang, Ying; Babich, Inna V.; Treichler, John; Yoon, Jung H.; Guarini, Kathryn; Solomon, Paul M.

    2001-09-01

    The double gate field effect transistor (FET) is an exploratory device that promises certain performance advantages compared to traditional CMOS FETs. It can be scaled down further than the traditional devices because of the greater electrostatic control by the gates on the channel (about twice as short a channel length for the same gate oxide thickness), has steeper sub-threshold slope and about double the current for the same width. This paper presents lithographic results for double gate FET's developed at IBM's T. J. Watson Research Center. The device is built on bonded wafers with top and bottom gates self-aligned to each other. The channel is sandwiched between the top and bottom polysilicon gates and the gate length is defined using DUV lithography. An alternating phase shift mask was used to pattern gates with critical dimensions of 75 nm, 100 nm and 125 nm in photoresist. 50 nm gates in photoresist have also been patterned by 20% over-exposure of nominal 100 nm lines. No trim mask was needed because of a specific way the device was laid out. UV110 photoresist from Shipley on AR-3 antireflective layer were used. Process windows, developed and etched patterns are presented.

  14. Conical Double Frequency Emission by Femtosecond Laser Pulses from DKDP

    International Nuclear Information System (INIS)

    Xi-Peng, Zhang; Hong-Bing, Jiang; Shan-Chun, Tang; Qi-Huang, Gong

    2009-01-01

    Conical double frequency emission is investigated by femtosecond laser pulses at a wavelength of 800 nm in a DKDP crystal. It is demonstrated that the sum frequency of incident wave and its scattering wave accounts for the conical double frequency emission. The gaps on the conical rings are observed and they are very sensitive to the propagation direction, and thus could be used to detect the small angle deviation of surface direction. (fundamental areas of phenomenology (including applications))

  15. Efficient 525 nm laser generation in single or double resonant cavity

    Science.gov (United States)

    Liu, Shilong; Han, Zhenhai; Liu, Shikai; Li, Yinhai; Zhou, Zhiyuan; Shi, Baosen

    2018-03-01

    This paper reports the results of a study into highly efficient sum frequency generation from 792 and 1556 nm wavelength light to 525 nm wavelength light using either a single or double resonant ring cavity based on a periodically poled potassium titanyl phosphate crystal (PPKTP). By optimizing the cavity's parameters, the maximum power achieved for the resultant 525 nm laser was 263 and 373 mW for the single and double resonant cavity, respectively. The corresponding quantum conversion efficiencies were 8 and 77% for converting 1556 nm photons to 525 nm photons with the single and double resonant cavity, respectively. The measured intra-cavity single pass conversion efficiency for both configurations was about 5%. The performances of the sum frequency generation in these two configurations was studied and compared in detail. This work will provide guidelines for optimizing the generation of sum frequency generated laser light for a variety of configurations. The high conversion efficiency achieved in this work will help pave the way for frequency up-conversion of non-classical quantum states, such as the squeezed vacuum and single photon states. The proposed green laser source will be used in our future experiments, which includes a plan to generate two-color entangled photon pairs and achieve the frequency down-conversion of single photons carrying orbital angular momentum.

  16. Metastable Magnesium fluorescence spectroscopy using a frequency-stabilized 517 nm laser

    DEFF Research Database (Denmark)

    He, Ming; Jensen, Brian B; Therkildsen, Kasper T

    2009-01-01

    We present a laser operating at 517 nm for our Magnesium laser-cooling and atomic clock project. A two-stage Yb-doped fiber amplifier (YDFA) system generates more than 1.5 W of 1034 nm light when seeded with a 15 mW diode laser. Using a periodically poled lithium niobate (PPLN) waveguide, we...... obtained more than 40 mW of 517 nm output power by single pass frequency doubling. In addition, fluorescence spectroscopy of metastable magnesium atoms could be used to stabilize the 517 nm laser to an absolute frequency within 1 MHz....

  17. Metastable Magnesium fluorescence spectroscopy using a frequency-stabilized 517 nm laser

    DEFF Research Database (Denmark)

    He, Ming; Jensen, Brian B; Therkildsen, Kasper T

    2009-01-01

    We present a laser operating at 517 nm for our Magnesium laser-cooling and atomic clock project. A two-stage Yb-doped fiber amplifier (YDFA) system generates more than 1.5 W of 1034 nm light when seeded with a 15 mW diode laser. Using a periodically poled lithium niobate (PPLN) waveguide, we obta...... obtained more than 40 mW of 517 nm output power by single pass frequency doubling. In addition, fluorescence spectroscopy of metastable magnesium atoms could be used to stabilize the 517 nm laser to an absolute frequency within 1 MHz.......We present a laser operating at 517 nm for our Magnesium laser-cooling and atomic clock project. A two-stage Yb-doped fiber amplifier (YDFA) system generates more than 1.5 W of 1034 nm light when seeded with a 15 mW diode laser. Using a periodically poled lithium niobate (PPLN) waveguide, we...

  18. Absolute frequency atlas from 915 nm to 985 nm based on laser absorption spectroscopy of iodine

    Science.gov (United States)

    Nölleke, Christian; Raab, Christoph; Neuhaus, Rudolf; Falke, Stephan

    2018-04-01

    This article reports on laser absorption spectroscopy of iodine gas between 915 nm and 985 nm. This wavelength range is scanned utilizing a narrow linewidth and mode-hop-free tunable diode-laser whose frequency is actively controlled using a calibrated wavelength meter. This allows us to provide an iodine atlas that contains almost 10,000 experimentally observed reference lines with an uncertainty of 50 MHz. For common lines, good agreement is found with a publication by Gerstenkorn and Luc (1978). The new rich dataset allows existing models of the iodine molecule to be refined and can serve as a reference for laser frequency calibration and stabilization.

  19. Precise frequency measurements of iodine hyperfine transitions at 671 nm.

    Science.gov (United States)

    Huang, Yao-Chin; Chen, Hsuan-Chen; Chen, Shih-En; Shy, Jow-Tsong; Wang, Li-Bang

    2013-03-01

    We report absolute frequency measurements on the a(1), a(10), and a(15) hyperfine components of the R(78) 4-6 line of (127)I(2). An external-cavity diode laser system at 671 nm is frequency-stabilized to the saturated absorption center obtained by modulation transfer spectroscopy in an iodine vapor cell. Its absolute frequency is measured by an optical frequency comb. The effect of pressure shift is investigated to obtain the absolute transition frequency at zero pressure. Our determination of the line centers reaches a precision of better than 40 kHz and will provide useful input for theoretical calculations. This frequency-stabilized laser can be used as a reference laser for the spectroscopy of lithium D lines.

  20. GAP IN A LASER FREQUENCY He-Ne AT 632.8 nm A. Aissani , M ...

    African Journals Online (AJOL)

    30 juin 2012 ... forme de raie qui se traduit par un déplacement du creux du Lamb-dip. Mots-clés: forme de raie, laser à double sorties, déplacement en fréquence. How to cite this article. Aissani A, Alliche M, Chaalal M and Ziane O. Frequency difference in a laser He-Ne A. 632.8 nm. J Fundam Appl Sci. 2012, 4(1), 39-45.

  1. Frequency Doubling Broadband Light in Multiple Crystals

    International Nuclear Information System (INIS)

    Alford, William J.; Smith, Arlee V.

    2000-01-01

    The authors compare frequency doubling of broadband light in a single nonlinear crystal with doubling in five crystals with intercrystal temporal walk off compensation, and with doubling in five crystals adjusted for offset phase matching frequencies. Using a plane-wave, dispersive numerical model of frequency doubling they study the bandwidth of the second harmonic and the conversion efficiency as functions of crystal length and fundamental irradiance. For low irradiance the offset phase matching arrangement has lower efficiency than a single crystal of the same total length but gives a broader second harmonic bandwidth. The walk off compensated arrangement gives both higher conversion efficiency and broader bandwidth than a single crystal. At high irradiance, both multicrystal arrangements improve on the single crystal efficiency while maintaining broad bandwidth

  2. Linearly frequency-modulated pulsed single-frequency fiber laser at 1083 nm.

    Science.gov (United States)

    Zhang, Yuanfei; Yang, Changsheng; Li, Can; Feng, Zhouming; Xu, Shanhui; Deng, Huaqiu; Yang, Zhongmin

    2016-02-22

    A linearly frequency-modulated, actively Q-switched, single-frequency ring fiber laser based on injection seeding from an ultra-short cavity is demonstrated at 1083 nm. A piezoelectric transducer is employed to obtain linearly frequency-modulating performance and over 1.05 GHz frequency-tuning range is achieved with a modulating frequency reaching tens of kilohertz. A maximum peak power of the stable output pulse is over 3.83 W during frequency-modulating process. This type of pulsed fiber laser provides a promising candidate for coherent LIDAR in the measurement of thermosphere.

  3. Single frequency 1645 nm Er:YAG nonplanar ring oscillator resonantly pumped by a 1470 nm laser diode.

    Science.gov (United States)

    Zheng, Yan; Gao, Chunqing; Wang, Ran; Gao, Mingwei; Ye, Qing

    2013-03-01

    A 1645 nm Er:YAG nonplanar ring oscillator, resonantly pumped by a 1470 nm laser diode, is reported. By using a 0.5%-doped Er:YAG nonplanar ring resonator, a 0.284 W single-frequency laser output at 1645 nm was obtained with a slope efficiency of 42.1%. The beam quality in x and y directions were 1.064 and 1.039, respectively.

  4. Effect of frequency-doubling pulse Nd:YAG laser on microbial mutation

    Science.gov (United States)

    Zhao, Yansheng; Wang, Luyan; Zheng, Heng; Yin, Hongping; Chen, Xiangdong; Tan, Zheng; Wu, Wutong

    1999-09-01

    We are going to report the mutagenic effect of frequency-doubling pulse Nd:YAG laser (532 nm) on microbe. After irradiation with pulse laser, mutants of abscisic acid producing strains and erythromycin producing strains were obtained, one of which could produce 62.1% and 57% more products than control, respectively. In the study of mutagenization of Spirulina platensis caused by pulse laser, we selected a high photosynthetic strains, with improved productivity of protein and exocellular ploysaccharides of 12% and 246%, respectively. The experimental results indicate that frequency-doubling pulse laser (532 nm) is a potential new type of physical mutagenic factor.

  5. Frequency doubling perimetry using a liquid crystal display.

    Science.gov (United States)

    Spry, P G; Gibbs, M L; Johnson, C A; Howard, D L

    2001-03-01

    To compare frequency doubling contrast thresholds using a new liquid crystal window display with those obtained with the commercial video-based Frequency Doubling Technology perimeter. One eye of 49 glaucoma patients and one eye of 49 normal controls were tested with the liquid crystal window and Frequency Doubling Technology systems. Both displays employed identical stimulus conditions and test strategies, although the dynamic range of the liquid crystal window-based display was approximately 30% smaller than that of the Frequency Doubling Technology system. Measurements were repeated using the video-based Frequency Doubling Technology perimeter in a subset of 21 eyes. Relationships between and within displays were assessed using a chance-corrected agreement measure (quadratic weighted kappa) and paired measurement differences. Variability was quantified using standard deviation from the mean paired measurement difference. Over the restricted operating range of the liquid crystal display system, between-display and within-video display variability was 2.3 dB and 3.2 dB, respectively, between-display agreement was 0.66, and within-display agreement (test-retest for Frequency Doubling Technology) was 0.65. Levels of agreement and variability between the two frequency doubling displays were of similar magnitude to repeated (test-retest) Frequency Doubling Technology measures, suggesting that contrast threshold measurements made using the two displays may be used interchangeably. However, the operating range of the current liquid crystal window-based display is smaller.

  6. Production of 10.4 W of single frequency coherent light at 780 nm by second harmonic generation

    Science.gov (United States)

    Lichtman, Martin; Piotrowicz, Michal; Saffman, Mark

    2013-05-01

    We have developed a high power, 10.4 W single frequency source at 780 nm, using second harmonic generation in a double-pass arrangement through a 50 mm long PPLN crystal. The source power is from a 20 W erbium-doped fiber amplifier at 1560 nm, giving a conversion efficiency of 52%. Comparison of the conversion efficiency with calculations based on a modified Boyd-Kleinman theory and numerical solution of the non-linear Schrödinger equation will be presented. The 780 nm light is used to create an array of blue-detuned traps for quantum computing experiments with Cs atoms. This work was supported by IARPA through ARO and DARPA through AFOSR.

  7. Comparison of symmetric and asymmetric double quantum well extended-cavity diode lasers for broadband passive mode-locking at 780  nm.

    Science.gov (United States)

    Christopher, Heike; Kovalchuk, Evgeny V; Wenzel, Hans; Bugge, Frank; Weyers, Markus; Wicht, Andreas; Peters, Achim; Tränkle, Günther

    2017-07-01

    We present a compact, mode-locked diode laser system designed to emit a frequency comb in the wavelength range around 780 nm. We compare the mode-locking performance of symmetric and asymmetric double quantum well ridge-waveguide diode laser chips in an extended-cavity diode laser configuration. By reverse biasing a short section of the diode laser chip, passive mode-locking at 3.4 GHz is achieved. Employing an asymmetric double quantum well allows for generation of a mode-locked optical spectrum spanning more than 15 nm (full width at -20  dB) while the symmetric double quantum well device only provides a bandwidth of ∼2.7  nm (full width at -20  dB). Analysis of the RF noise characteristics of the pulse repetition rate shows an RF linewidth of about 7 kHz (full width at half-maximum) and of at most 530 Hz (full width at half-maximum) for the asymmetric and symmetric double quantum well devices, respectively. Investigation of the frequency noise power spectral density at the pulse repetition rate shows a white noise floor of approximately 2100  Hz 2 /Hz and of at most 170  Hz 2 /Hz for the diode laser employing the asymmetric and symmetric double quantum well structures, respectively. The pulse width is less than 10 ps for both devices.

  8. Efficient generation of 509 nm light by sum-frequency mixing between two tapered diode lasers

    DEFF Research Database (Denmark)

    Tawfieq, Mahmoud; Jensen, Ole Bjarlin; Hansen, Anders Kragh

    2015-01-01

    We demonstrate a concept for visible laser sources based on sum-frequency generation of beam com- bined tapered diode lasers. In this specific case, a 1.7 W sum-frequency generated green laser at 509 nm is obtained, by frequency adding of 6.17 W from a 978 nm tapered diode laser with 8.06 W from...... a 1063 nm tapered diode laser, inside a periodically poled MgO doped lithium niobate crystal. This corresponds to an optical to optical conversion ef fi ciency of 12.1%. As an example of potential applica- tions, the generated nearly diffraction-limited green light is used for pumping a Ti:sapphire laser...

  9. Frequency locking of compact laser-diode modules at 633 nm

    Science.gov (United States)

    Nölleke, Christian; Leisching, Patrick; Blume, Gunnar; Jedrzejczyk, Daniel; Pohl, Johannes; Feise, David; Sahm, Alexander; Paschke, Katrin

    2018-02-01

    This work reports on a compact diode-laser module emitting at 633 nm. The emission frequency can be tuned with temperature and current, while optical feedback of an internal DBR grating ensures single-mode operation. The laser diode is integrated into a micro-fabricated package, which includes optics for beam shaping, a miniaturized optical isolator, and a vapor cell as frequency reference. The achieved absolute frequency stability is below 10-8 , while the output power can be more than 10 mW. This compact absolute frequency-stabilized laser system can replace gas lasers and may be integrated in future quantum technology devices.

  10. Multiorder nonlinear diffraction in frequency doubling processes

    DEFF Research Database (Denmark)

    Saltiel, Solomon M.; Neshev, Dragomir N.; Krolikowski, Wieslaw

    2009-01-01

    We analyze experimentally light scattering from 2 nonlinear gratings and observe two types of second-harmonic frequency-scattering processes. The first process is identified as Raman–Nath type nonlinear diffraction that is explained by applying only transverse phase-matching conditions. The angular...... position of this type of diffraction is defined by the ratio of the second-harmonic wavelength and the grating period. In contrast, the second type of nonlinear scattering process is explained by the longitudinal phase matching only, being insensitive to the nonlinear grating...

  11. Design technology co-optimization for 14/10nm metal1 double patterning layer

    Science.gov (United States)

    Duan, Yingli; Su, Xiaojing; Chen, Ying; Su, Yajuan; Shao, Feng; Zhang, Recco; Lei, Junjiang; Wei, Yayi

    2016-03-01

    Design and technology co-optimization (DTCO) can satisfy the needs of the design, generate robust design rule, and avoid unfriendly patterns at the early stage of design to ensure a high level of manufacturability of the product by the technical capability of the present process. The DTCO methodology in this paper includes design rule translation, layout analysis, model validation, hotspots classification and design rule optimization mainly. The correlation of the DTCO and double patterning (DPT) can optimize the related design rule and generate friendlier layout which meets the requirement of the 14/10nm technology node. The experiment demonstrates the methodology of DPT-compliant DTCO which is applied to a metal1 layer from the 14/10nm node. The DTCO workflow proposed in our job is an efficient solution for optimizing the design rules for 14/10 nm tech node Metal1 layer. And the paper also discussed and did the verification about how to tune the design rule of the U-shape and L-shape structures in a DPT-aware metal layer.

  12. Self-frequency doubling in a laser-active whispering-gallery resonator.

    Science.gov (United States)

    Herr, Simon J; Folwill, Yannick; Buse, Karsten; Breunig, Ingo

    2017-07-01

    Lasing and self-frequency doubling are achieved in a millimeter-sized laser-active whispering-gallery resonator made of neodymium-doped lithium niobate. A low-cost 808-nm laser diode without external frequency stabilization is sufficient to pump the neodymium ions. Laser oscillation around 1.08 μm drives a frequency-doubling process within the same cavity providing green light. The electrical-optical efficiency of the system reaches up to 2×10 -4 . To the best of our knowledge, this is the first demonstration of combining lasing and χ (2) frequency conversion in a single high-Q whispering-gallery resonator. This approach is general and can be applied to other materials and other nonlinear optical processes.

  13. Device and circuit performance analysis of double gate junctionless transistors at L(g = 18 nm

    Directory of Open Access Journals (Sweden)

    Chitrakant Sahu

    2014-04-01

    Full Text Available The design and characteristics of double-gate (DG junctionless (JL devices are compared with the DG inversion-mode (IM field effect transistors (FETs at 45 nm technology node with effective channel length of 18 nm. The comparison are performed at iso-V(th for both n- and p-type of devices. The JL device shows lower drain-induced barrier lowering, steep subthreshold slope and lower OFF state current. For the first time, the authors demonstrate a pass gate (PG logic, inverter circuit and static random access memory (SRAM stability analysis using JL devices, rather than a complementary metal-oxide semiconductor (CMOS configuration. They observed that transient response of JL PG configuration is similar to that of conventional CMOS PGs. JL inverter also shows similar transient characteristics with 25% reduction in delay and 12% improvement in 6 T SRAM cell stability compared with IMFETs, which shows large potential in digital circuit applications. The simulations were performed using coupled device-circuit methodology in ATLAS technology aided computer design (TCAD mixed-mode simulator.

  14. 486nm blue laser operating at 500 kHz pulse repetition frequency

    Science.gov (United States)

    Creeden, Daniel; Blanchard, Jon; Pretorius, Herman; Limongelli, Julia; Setzler, Scott D.

    2016-03-01

    Compact, high power blue light in the 470-490nm region is difficult to generate due to the lack of laser sources which are easily convertible (through parametric processes) to those wavelengths. By using a pulsed Tm-doped fiber laser as a pump source for a 2-stage second harmonic generation (SHG) scheme, we have generated ~2W of 486.5nm light at 500kHz pulse repetition frequency (PRF). To our knowledge, this is the highest PRF and output power achieved in the blue region based on a frequency converted, monolithic fiber laser. This pump laser is a pulsed Tm-doped fiber laser/amplifier which generates 12.8W of 1946nm power at 500kHz PRF with diffraction-limited output from a purely single-mode fiber. The output from this laser is converted to 973nm through second harmonic generation (SHG). The 973nm is then converted to 486.5nm via another SHG stage. This architecture operates with very low peak power, which can be challenging from a nonlinear conversion standpoint. However, the low peak power enables the use of a single-mode monolithic fiber amplifier without undergoing nonlinear effects in the fiber. This also eliminates the need for novel fiber designs, large-mode area fiber, or free-space coupling to rod-type amplifiers, improving reliability and robustness of the laser source. Higher power and conversion efficiency are possible through the addition of Tm-doped fiber amplification stages as well as optimization of the nonlinear conversion process and nonlinear materials. In this paper, we discuss the laser layout, results, and challenges with generating blue light using a low peak power approach.

  15. Tunable-wavelength picosecond vortex generation in fiber and its application in frequency-doubled vortex

    Science.gov (United States)

    Zhang, Wending; Wei, Keyan; Wang, Heng; Mao, Dong; Gao, Feng; Huang, Ligang; Mei, Ting; Zhao, Jianlin

    2018-01-01

    We present a method for tunable-wavelength picosecond vortex pulse generation by using an acoustically-induced fiber grating (AIFG). The AIFG-driven mode conversion characteristic was activated via a shear-mode piezoelectric transducer that excels in excitation efficiency of acoustic flexural wave and mechanical stability. The linearly-polarized ±1-order picosecond vortex pulse was experimentally generated via AIFG with a uniform coupling efficiency of ∼98.4% from the fundamental mode to the ±1-order vortex mode within the wavelength range 1540 nm ∼ 1560 nm. The topological charge and the linearly-polarized characteristic of the picosecond vortex pulse were verified by examination of the off-axial interference and the polarization angle-dependent intensity, respectively. Furthermore, the picosecond vortex pulse with wavelength tunability was input to a nonlinear BBO crystal to generate a frequency-doubled ±2-order vortex in the wavelength range 770 nm ∼ 780 nm. This technology provides a convenient apparatus for generating a picosecond vortex pulse and the frequency-doubled vortex with wavelength tunability.

  16. Development of scalable frequency and power Phase-Locked Loop in 130nm CMOS technology

    CERN Document Server

    Firlej, M; Idzik, M; Moron, J; Swientek, K

    2014-01-01

    The design and measurements results of a prototype very low power Phase-Locked Loop (PLL) ASIC for applications in readout systems of particle physics detectors are presented. The PLL was fabricated in 130 nm CMOS technology. It was designed and simulated for frequency range 10 MHz–3.5 GHz. Four division factors i.e. 6, 8, 10 and 16 were implemented in the PLL feedback loop. The main PLL block-voltage controlled oscillator (VCO) should work in 16 frequency ranges/modes, switched either manually or automatically. Preliminary measurements done in frequency range 20 MHz–1.6 GHz showed that the ASIC is functional and generates proper clock signal. The automatic VCO mode switching, one of the main design goals, was positively verified. Power consumption of around 0.6mW was measured at 1 GHz for a division factor equal to 10.

  17. Development of scalable frequency and power Phase-Locked Loop in 130 nm CMOS technology

    International Nuclear Information System (INIS)

    Firlej, M; Fiutowski, T; Idzik, M; Moroń, J; Świentek, K

    2014-01-01

    The design and measurements results of a prototype very low power Phase-Locked Loop (PLL) ASIC for applications in readout systems of particle physics detectors are presented. The PLL was fabricated in 130 nm CMOS technology. It was designed and simulated for frequency range 10 MHz–3.5 GHz. Four division factors i.e. 6, 8, 10 and 16 were implemented in the PLL feedback loop. The main PLL block-voltage controlled oscillator (VCO) should work in 16 frequency ranges/modes, switched either manually or automatically. Preliminary measurements done in frequency range 20 MHz–1.6 GHz showed that the ASIC is functional and generates proper clock signal. The automatic VCO mode switching, one of the main design goals, was positively verified. Power consumption of around 0.6 mW was measured at 1 GHz for a division factor equal to 10

  18. Frequency Stabilization of DFB Laser Diodes at 1572 nm for Spaceborne Lidar Measurements of CO2

    Science.gov (United States)

    Numata, Kenji; Chen, Jeffrey R.; Wu, Stewart T.; Abshire, James B.; Krainak, Michael A.

    2010-01-01

    We report a fiber-based, pulsed laser seeder system that rapidly switches among 6 wavelengths across atmospheric carbon dioxide (CO2) absorption line near 1572.3 nm for measurements of global CO2 mixing ratios to 1-ppmv precision. One master DFB laser diode has been frequency-locked to the CO2 line center using a frequency modulation technique, suppressing its peak-to-peak frequency drifts to 0.3 MHz at 0.8 sec averaging time over 72 hours. Four online DFB laser diodes have been offset-locked to the master laser using phase locked loops, with virtually the same sub-MHz absolute accuracy. The 6 lasers were externally modulated and then combined to produce the measurement pulse train.

  19. Absolute frequencies of water lines near 790 nm with 10-11 accuracy

    Science.gov (United States)

    Chen, J.; Hua, T.-P.; Tao, L.-G.; Sun, Y. R.; Liu, A.-W.; Hu, S.-M.

    2018-01-01

    Water lines in the infrared are convenient frequency references. We present absolute positions of several H216O ro-vibrational transitions around 790 nm using comb-locked cavity ring-down saturation spectroscopy. Lamb dips of 6 water lines with saturation power in the range of 70-130 kW/cm2 were observed and the line positions were determined with an accuracy of 25 kHz, corresponding to a fractional uncertainty of 6.6 × 10-11. The present work demonstrates the capability to considerably improve the accuracy of the water line positions in the infrared.

  20. 100 mW of blue light at 405 nm from intracavity doubling of CW Ti:Sapphire laser utilising BiBO-crystal

    DEFF Research Database (Denmark)

    Thorhauge, Morten; Mortensen, Jesper Liltorp; Tidemand-Lichtenberg, Peter

    2006-01-01

    100 mW of coherent blue light with a wavelength of 405 nm was generated utilising a BiB3O6 (BiBO) nonlinear crystal to frequency double a Ti:Sapphire laser. Phase match curves as well as sensitivity to angular misalignment was calculated. The BiBO crystal was found to be excellent...... for this application. Temperature dependance was uncritical for this crystal, while power stability was good. The pump-to-blue optical conversion efficiency was approximately 2%. Unfortunately catastrophic coating damage was observed...

  1. Translocation frequency of double-stranded DNA through a solid-state nanopore

    Science.gov (United States)

    Bell, Nicholas A. W.; Muthukumar, Murugappan; Keyser, Ulrich F.

    2016-01-01

    Solid-state nanopores are single-molecule sensors that measure changes in ionic current as charged polymers such as DNA pass through. Here, we present comprehensive experiments on the length, voltage, and salt dependence of the frequency of double-stranded DNA translocations through conical quartz nanopores with mean opening diameter 15 nm. We observe an entropic barrier-limited, length-dependent translocation frequency at 4M LiCl salt concentration and a drift-dominated, length-independent translocation frequency at 1M KCl salt concentration. These observations are described by a unifying convection-diffusion equation, which includes the contribution of an entropic barrier for polymer entry. PMID:26986356

  2. Frequency-domain lifetime fluorometry of double-labeled creatine kinase.

    Science.gov (United States)

    Gregor, M; Kubala, M; Amler, E; Mejsnar, J

    2003-01-01

    Myofibril-bound creatine kinase EC 2.7.3.2 (CK), a key enzyme of muscle energy metabolism, has been selected for studies of conformational changes that underlie the cellular control of enzyme activity. For fluorescence spectroscopy measurements, the CK molecule was double-labeled with IAF (5-iodoacetamidofluorescein) and ErITC (erythrosin 5'-isothiocyanate). Measurement of fluorescence resonance energy transfer (FRET) from fluorescein to erythrosin was used to obtain information about the donor-acceptor pair distance. Frequency-domain lifetime measurements evaluate the donor-acceptor distance in the native CK molecule as 7.8 nm. The Förster radius equals 5.3 nm with the resolution range from 0.2 to 1.0 nm. Erythrosin-fluorescein labeling (EFL) was tested for artificial conformational changes of the CK molecule with high-salt concentration treatment. The transition distance, defined by His-97 and Cys-283 and derived from a 3D model equals 0.766 nm for the open (inactive) form and 0.277 nm for the closed (reactive) form of the CK molecule. In this way, the resolution range of the used spectroscopy method is significant, concerning the difference of 0.489 nm. Nevertheless, the CK enzyme activity, assessed by the hexokinase-coupled assay, was diminished down to 1 % of the activity of the native enzyme. EFL is suitable for description of conformational behavior implied from the regulation of creatine kinase. However, the observed inhibition restricts EFL to studies of conformational changes during natural catalytic activity.

  3. Nonequilibrium ferroelectric-ferroelastic 10 nm nanodomains: wrinkles, period-doubling, and power-law relaxation.

    Science.gov (United States)

    Scott, James F; Evans, Donald M; Katiyar, Ram S; McQuaid, Raymond G P; Gregg, J Marty

    2017-08-02

    Since the 1935 work of Landau-Lifshitz and of Kittel in 1946 all ferromagnetic, ferroelectric, and ferroelastic domains have been thought to be straight-sided with domain widths proportional to the square root of the sample thickness. We show in the present work that this is not true. We also discover period doubling domains predicted by Metaxas et al (2008 Phys. Rev. Lett. 99 217208) and modeled by Wang and Zhao (2015 Sci. Rep. 5 8887). We examine non-equilibrium ferroic domain structures in perovskite oxides with respect to folding, wrinkling, and relaxation and suggest that structures are kinetically limited and in the viscous flow regime predicted by Metaxas et al in 2008 but never observed experimentally. Comparisons are made with liquid crystals and hydrodynamic instabilities, including chevrons, and fractional power-law relaxation. As Shin et al (2016 Soft Matter 12 3502) recently emphasized: 'An understanding of how these folds initiate, propagate, and interact with each other is still lacking'. Inside each ferroelastic domain are ferroelectric 90° nano-domains with 10 nm widths and periodicity in agreement with the 10 nm theoretical minima predicted by Feigl et al (2014 Nat. Commun. 5 4677). Evidence is presented for domain-width period doubling, which is common in polymer films but unknown in ferroic domains. A discussion of the folding-to-period doubling phase transition model of Wang and Zhao is included.

  4. High-speed, high-resolution optical coherence tomography retinal imaging with a frequency-swept laser at 850 nm.

    Science.gov (United States)

    Srinivasan, V J; Huber, R; Gorczynska, I; Fujimoto, J G; Jiang, J Y; Reisen, P; Cable, A E

    2007-02-15

    High-speed, high-resolution optical coherence tomography (OCT) imaging of the human retina is demonstrated using a frequency-swept laser at 850 nm. A compact external cavity semiconductor laser design, optimized for swept-source ophthalmic OCT, is described. The laser enables an effective 16 kHz sweep rate with >10 mm coherence length and a tuning range of approximately 35 nm full width at half-maximum, yielding an axial resolution of <7 micro m in tissue.

  5. Frequency-doubled diode laser for direct pumping of Ti:sapphire lasers

    DEFF Research Database (Denmark)

    Müller, André; Jensen, Ole Bjarlin; Unterhuber, Angelika

    2012-01-01

    A single-pass frequency doubled high-power tapered diode laser emitting nearly 1.3 W of green light suitable for direct pumping of Ti:sapphire lasers generating ultrashort pulses is demonstrated. The pump efficiencies reached 75 % of the values achieved with a commercial solid-state pump laser....... However, the superior electro-optical efficiency of the diode laser improves the overall efficiency of the Ti:sapphire laser by a factor > 2. The optical spectrum emitted by the Ti:sapphire laser shows a spectral width of 112 nm (FWHM). Based on autocorrelation measurements, pulse widths of less than 20...... fs are measured. These results open the opportunity of establishing diode laser pumped Ti:sapphire lasers for e.g. biophotonic applications like retinal optical coherence tomography or pumping of photonic crystal fibers for CARS microscopy....

  6. An innovative MRE absorber with double natural frequencies for wide frequency bandwidth vibration absorption

    International Nuclear Information System (INIS)

    Sun, Shuaishuai; Yang, Jian; Li, Weihua; Alici, Gursel; Deng, Huaxia; Du, Haiping; Yan, Tianhong

    2016-01-01

    A new design of adaptive tuned vibration absorber was proposed in this study for vibration reduction. The innovation of the new absorber is the adoption of the eccentric mass on the top of the multilayered magnetorheological elastomer (MRE) structure so that this proposed absorber has two vibration modes: one in the torsional direction and the other in translational direction. This property enables the absorber to expand its effective bandwidth and to be more capable of reducing the vibrations especially dealing with those vibrations with multi-frequencies. The innovative MRE absorber was designed and tested on a horizontal vibration table. The test results illustrate that the MRE absorber realized double natural frequencies, both of which are controllable. Inertia’s influence on the dynamic behavior of the absorber is also investigated in order to guide the design of the innovative MRE absorber. Additionally, the experimentally obtained natural frequencies coincide with the theoretical data, which sufficiently verifies the feasibility of this new design. The last part in terms of the vibration absorption ability also proves that both of these two natural frequencies play a great role in absorbing vibration energy. (paper)

  7. 500 nm Continuous Wave Tunable SingleFrequency MidIR Light Source for C–H Spectroscopy

    DEFF Research Database (Denmark)

    Høgstedt, Lasse; Jensen, Ole Bjarlin; Dam, Jeppe Seidelin

    2012-01-01

    A computer controlled tunable mid-IR light source, based on single resonant difference frequency generation (DFG), is experimentally investigated. The DFG process is pumped by an external cavity tapered diode laser, tunable over a spectral range of 30 nm. Grating feedback to the single mode channel...

  8. Miniature fiber-optic multiphoton microscopy system using frequency-doubled femtosecond Er-doped fiber laser.

    Science.gov (United States)

    Huang, Lin; Mills, Arthur K; Zhao, Yuan; Jones, David J; Tang, Shuo

    2016-05-01

    We report on a miniature fiber-optic multiphoton microscopy (MPM) system based on a frequency-doubled femtosecond Er-doped fiber laser. The femtosecond pulses from the laser source are delivered to the miniature fiber-optic probe at 1.58 µm wavelength, where a standard single mode fiber is used for delivery without the need of free-space dispersion compensation components. The beam is frequency-doubled inside the probe by a periodically poled MgO:LiNbO3 crystal. Frequency-doubled pulses at 786 nm with a maximum power of 80 mW and a pulsewidth of 150 fs are obtained and applied to excite intrinsic signals from tissues. A MEMS scanner, a miniature objective, and a multimode collection fiber are further used to make the probe compact. The miniature fiber-optic MPM system is highly portable and robust. Ex vivo multiphoton imaging of mammalian skins demonstrates the capability of the system in imaging biological tissues. The results show that the miniature fiber-optic MPM system using frequency-doubled femtosecond fiber laser can potentially bring the MPM imaging for clinical applications.

  9. Single crystal growth and nonlinear optical properties of Nd3+ doped STGS crystal for self-frequency-doubling application

    Science.gov (United States)

    Chen, Feifei; Wang, Lijuan; Wang, Xinle; Cheng, Xiufeng; Yu, Fapeng; Wang, Zhengping; Zhao, Xian

    2017-11-01

    The self-frequency-doubling crystal is an important kind of multi-functional crystal materials. In this work, Nd3+ doped Sr3TaGa3Si2O14 (Nd:STGS) single crystals were successfully grown by using Czochralski pulling method, in addition, the nonlinear and laser-frequency-doubling properties of Nd:STGS crystals were studied. The continuous-wave laser at 1064 nm was demonstrated along different physical axes, where the maximum output power was obtained to be 295 mW for the Z-cut samples, much higher than the Y-cut (242 mW) and X-cut (217 mW) samples. Based on the measured refractive indexes, the phase matching directions were discussed and determined for type I (42.5°, 30°) and type II (69.5°, 0°) crystal cuts. As expected, self-frequency-doubling green laser at 529 nm was achieved with output powers being around 16 mW and 12 mW for type I and type II configurations, respectively.

  10. Gap In A Laser Frequency He-Ne at 632.8 nm | Aissani | Journal of ...

    African Journals Online (AJOL)

    The aim of this work is to show that the emitted signals of a double-output laser cavity exhibit distinctive features, manifesting themselves through typical dissymmetry in the corresponding spectral line shapes. Usually, such a dissymmetry in an inhomogeneously broadened gas laser appears with a clear but unpredictable ...

  11. Analysis of frequency effect on variegated RAM styles and other parameters using 40 nm FPGA

    DEFF Research Database (Denmark)

    Sharma, Rashmi; Pandey, Bishwajeet; Sharma, Vaashu

    2018-01-01

    . This analysis has been performed using the XILINX 12.1 and IBM SPSS Statistics 21 software and VHDL language. Pipe_distributed style at comparatively lesser values of frequencies consumes the least power. Therefore, lesser values of frequencies should be maintained while observing the power. This would bloom up...

  12. Tunable High-Power Single-Frequency Laser at 2050 nm, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose a novel new architecture for a low-phase noise electronically tunable laser single-frequency laser at 2.05 microns that meets all the demanding...

  13. Frequency stabilization of distributed-feedback laser diodes at 1572 nm for lidar measurements of atmospheric carbon dioxide.

    Science.gov (United States)

    Numata, Kenji; Chen, Jeffrey R; Wu, Stewart T; Abshire, James B; Krainak, Michael A

    2011-03-01

    We demonstrate a wavelength-locked laser source that rapidly steps through six wavelengths distributed across a 1572.335 nm carbon dioxide (CO(2)) absorption line to allow precise measurements of atmospheric CO(2) absorption. A distributed-feedback laser diode (DFB-LD) was frequency-locked to the CO(2) line center by using a frequency modulation technique, limiting its peak-to-peak frequency drift to 0.3 MHz at 0.8 s averaging time over 72 hours. Four online DFB-LDs were then offset locked to this laser using phase-locked loops, retaining virtually the same absolute frequency stability. These online and two offline DFB-LDs were subsequently amplitude switched and combined. This produced a precise wavelength-stepped laser pulse train, to be amplified for CO(2) measurements. © 2011 Optical Society of America

  14. Frequency-swept laser light source at 1050 nm with higher bandwidth due to multiple semiconductor optical amplifiers in series

    DEFF Research Database (Denmark)

    Marschall, Sebastian; Thrane, Lars; Andersen, Peter E.

    2009-01-01

    We report on the development of an all-fiber frequency-swept laser light source in the 1050 nm range based on semiconductor optical amplifiers (SOA) with improved bandwidth due to multiple gain media. It is demonstrated that even two SOAs with nearly equal gain spectra can improve the performance......Hz) the SSOA configuration can maintain a significantly higher bandwidth (~50% higher) compared to the MOPA architecture. Correspondingly narrower point spread functions can be generated in a Michelson interferometer....

  15. A miniature frequency-stabilized VCSEL system emitting at 795 nm based on LTCC modules

    Science.gov (United States)

    Gruet, Florian; Vecchio, Fabrizio; Affolderbach, Christoph; Pétremand, Yves; de Rooij, Nico F.; Maeder, Thomas; Mileti, Gaetano

    2013-08-01

    We present a compact frequency-stabilized laser system locked to the Rubidium absorption line of a micro-fabricated reference cell. A printed circuit board (PCB) is used to carry all the components and part of the electronics, and low-temperature co-fired ceramic (LTCC) modules are used to temperature-stabilize the laser diode and the miniature Rubidium cell (cell inner dimensions: 5 mm diameter and 2 mm height). The measured frequency stability of the laser, in terms of Allan deviation, is ≤8×10-10 for integration times of 103-105s. The current overall dimensions of the system are 70×40×50 mm3, with good potential for realization of a frequency-stabilized laser module with few cm3 volume.

  16. Investigation of self-frequency doubling crystals, yttrium calcium oxyborate (YCOB), doped with neodymium or ytterbium

    Science.gov (United States)

    Ye, Qing

    1999-09-01

    There is a need for low cost red, green, and blue (RGB) lasers for a number of commercial applications such as high-resolution laser printing, full color laser display. While semiconductor lasers still have both availability (green and blue) and beam quality (red) problems, nonlinear frequency conversion of diode-pumped solid state lasers are good alternatives. Among them, self- frequency doubling is an attractive approach because of its simpler design and lower cost. Unfortunately, few known crystals possess self-frequency doubling property. A newly discovered yttrium calcium oxyborate (YCOB) can fill in the role because it has adequate lasing and nonlinear frequency conversion efficiency. More importantly, YCOB crystal melts congruently so that high quality, large size single crystals can be grown using conventional Czochralski melt pulling technique. The thermal mechanical properties, linear and nonlinear optical properties of YCOB, laser properties of Nd:YCOB and Yb:YCOB crystals were investigated. Based on the calculated second harmonic phase matching angles, Nd:YCOB laser rods were fabricated. Self-frequency doubled green emission with 62 mW output power and red emission with 16 mW output power were successfully demonstrated using diode-pumping. It is the first time to achieve the continuous wave (cw) red lasing in Nd doped rare-earth calcium oxyborates. Rare-earth ions doping in YCOB crystal can not only achieve lasing, but also affect the physical and chemical properties of the crystal. The stability field of YCOB is reduced in proportion to both the ionic size differences from yttrium and doping concentrations of the rare-earth ions. The doping also changes the linear and nonlinear optical properties of the material. For example, the second harmonic conversion efficiency of 20% Yb doped YCOB was enhanced by more than 15% compared to undoped YCOB. The absorption cutoff edge of 20% Yb:YCOB was red- shift by more than 60 nm. Similar effects were observed in

  17. Quantum frequency doubling based on tripartite entanglement with cavities

    Science.gov (United States)

    Juan, Guo; Zhi-Feng, Wei; Su-Ying, Zhang

    2016-02-01

    We analyze the entanglement characteristics of three harmonic modes, which are the output fields from three cavities with an input tripartite entangled state at fundamental frequency. The entanglement properties of the input beams can be maintained after their frequencies have been up-converted by the process of second harmonic generation. We have calculated the parametric dependences of the correlation spectrum on the initial squeezing factor, the pump power, the transmission coefficient, and the normalized analysis frequency of cavity. The numerical results provide references to choose proper experimental parameters for designing the experiment. The frequency conversion of the multipartite entangled state can also be applied to a quantum communication network. Project supported by the National Natural Science Foundation of China (Grant No. 91430109), the Specialized Research Fund for the Doctoral Program of Higher Education of China (Grant No. 20111401110004), and the Natural Science Foundation of Shanxi Province, China (Grant No. 2014011005-3).

  18. 1540-nm single frequency single-mode pulsed all fiber laser for coherent Doppler lidar

    Science.gov (United States)

    Zhang, Xin; Diao, Weifeng; Liu, Yuan; Liu, Jiqiao; Hou, Xia; Chen, Weibiao

    2015-02-01

    A single-mode single frequency eye-safe pulsed all fiber laser based on master oscillator power amplification structure is presented. This laser is composed of a narrow linewidth distributed laser diode seed laser and two-stage cascade amplifiers. 0.8 m longitudinally gradient strained erbium/ytterbium co-doped polarization-maintaining fiber with a core diameter of 10 μm is used as the gain fiber and two acoustic-optics modulators are adopted to enhance pulse extinction ratio. A peak power of 160 W and a pulse width of 200 ns at 10 kHz repetition rate are achieved with transform-limited linewidth and diffraction-limited beam quality. This laser will be employed in a compact short range coherent Doppler wind lidar.

  19. Frequency doubling of an InGaAs multiple quantum wells semiconductor disk laser

    Science.gov (United States)

    Lidan, Jiang; Renjiang, Zhu; Maohua, Jiang; Dingke, Zhang; Yuting, Cui; Peng, Zhang; Yanrong, Song

    2018-01-01

    We demonstrate a good beam quality 483 nm blue coherent radiation from a frequency doubled InGaAs multiple quantum wells semiconductor disk laser. The gain chip is consisted of 6 repeats of strain uncompensated InGaAs/GaAs quantum wells and 25 pairs of GaAs/AlAs distributed Bragg reflector. A 4 × 4 × 7 mm3 type I phase-matched BBO nonlinear crystal is used in a V-shaped laser cavity for the second harmonic generation, and 210 mW blue output power is obtained when the absorbed pump power is 3.5 W. The M2 factors of the laser beam in x and y directions are about 1.04 and 1.01, respectively. The output power of the blue laser is limited by the relatively small number of the multiple quantum wells, and higher power can be expected by increasing the number of the multiple quantum wells and improving the heat management of the laser.

  20. Quad-Chip Double-Balanced Frequency Tripler

    Science.gov (United States)

    Lin, Robert H.; Ward, John S.; Bruneau, Peter J.; Mehdi, Imran; Thomas, Bertrand C.; Maestrini, Alain

    2010-01-01

    Solid-state frequency multipliers are used to produce tunable broadband sources at millimeter and submillimeter wavelengths. The maximum power produced by a single chip is limited by the electrical breakdown of the semiconductor and by the thermal management properties of the chip. The solution is to split the drive power to a frequency tripler using waveguides to divide the power among four chips, then recombine the output power from the four chips back into a single waveguide. To achieve this, a waveguide branchline quadrature hybrid coupler splits a 100-GHz input signal into two paths with a 90 relative phase shift. These two paths are split again by a pair of waveguide Y-junctions. The signals from the four outputs of the Y-junctions are tripled in frequency using balanced Schottky diode frequency triplers before being recombined with another pair of Y-junctions. A final waveguide branchline quadrature hybrid coupler completes the combination. Using four chips instead of one enables using four-times higher power input, and produces a nearly four-fold power output as compared to using a single chip. The phase shifts introduced by the quadrature hybrid couplers provide isolation for the input and output waveguides, effectively eliminating standing waves between it and surrounding components. This is accomplished without introducing the high losses and expense of ferrite isolators. A practical use of this technology is to drive local oscillators as was demonstrated around 300 GHz for a heterodyne spectrometer operating in the 2-3-THz band. Heterodyne spectroscopy in this frequency band is especially valuable for astrophysics due to the presence of a very large number of molecular spectral lines. Besides high-resolution radar and spectrographic screening applications, this technology could also be useful for laboratory spectroscopy.

  1. Three-dimensional and C-mode OCT imaging with a compact, frequency swept laser source at 1300 nm.

    Science.gov (United States)

    Huber, R; Wojtkowski, M; Fujimoto, James G; Jiang, J Y; Cable, A E

    2005-12-26

    We demonstrate high resolution, three-dimensional OCT imaging with a high speed, frequency swept 1300 nm laser source. A new external cavity semiconductor laser design, optimized for application to swept source OCT, is discussed. The design of the laser enables adjustment of an internal spectral filter to change the filter bandwidth and provides a robust bulk optics design. The laser generates ~30 mW instantaneous peak power at an effective 16 kHz sweep rate with a tuning range of ~133 nm full width. In frequency domain reflectometry and OCT applications, 109 dB sensitivity and ~10 microm axial resolution in tissue can be achieved with the swept laser. The high imaging speeds enable three-dimensional OCT imaging, including zone focusing or C-mode imaging and image fusion to acquire large depth of field data sets with high resolution. In addition, three-dimensional OCT data provides coherence gated en face images similar to optical coherence microscopy (OCM) and also enables the generation of images similar to confocal microscopy by summing signals in the axial direction. High speed, three-dimensional OCT imaging can provide comprehensive data which combines the advantages of optical coherence tomography and microscopy in a single system.

  2. Temperature investigation of infrared-to-visible frequency upconversion in erbium-doped tellurite glasses excited at 1540 nm

    International Nuclear Information System (INIS)

    Vermelho, M.V.D.; Gouveia-Neto, A.S.; Amorim, H.T.; Cassanjes, F.C.; Ribeiro, S.J.L.; Messaddeq, Y.

    2003-01-01

    Temperature investigation of infrared-to-visible frequency upconversion in erbium-doped tellurite glasses excited by CW laser radiation at 1540 nm and under cryogenic temperatures is reported. Intense upconversion emission signals around 530, 550 and 660 nm corresponding to the 2 H 11/2 , 4 S 3/2 , and 4 F 9/2 transitions to the 4 I 15/2 ground state were generated and studied as a function of the laser intensity and temperature. The upconversion excitation mechanism of the Er 3+ ions emitting energy levels was accomplished via stepwise multiphoton absorption. The green upconversion luminescence exhibited a fivefold intensity enhancement when the temperature of the sample was varied in the range between 5 and 300 K. A maximum green upconversion intensity was attained around 120 K and a steady decreasing behavior for higher temperatures up to 300 K was observed. A model based upon conventional rate equations was used to model the observed temperature evolution of the upconversion luminescence

  3. Simultaneous spatial and temporal walk-off compensation in frequency-doubling femtosecond pulses in β -BaB2O4

    International Nuclear Information System (INIS)

    Gehr, R.J.; Kimmel, M.W.; Smith, A.V.

    1998-01-01

    We experimentally demonstrate the benefits of simultaneous compensation of spatial and temporal walk-off in frequency doubling of 800-nm 250-fs pulses, using three active and two compensating β-BaB 2 O 4 crystals. The compensating crystals reverse both birefringent and group-velocity walk-off, resulting in a factor-of-4.5 improvement in doubling efficiency relative to one of the active crystals while maintaining the short pulse duration and the symmetric spatial profile that are characteristic of the single crystal. copyright 1998 Optical Society of America

  4. Impact of strain on electronic and transport properties of 6 nm hydrogenated germanane nano-ribbon channel double gate field effect transistor

    Science.gov (United States)

    Meher Abhinav, E.; Sundararaj, Anuraj; Gopalakrishnan, Chandrasekaran; Kasmir Raja, S. V.; Chokhra, Saurabh

    2017-11-01

    In this work, chair like fully hydrogenated germanane (CGeH) nano-ribbon 6 nm short channel double gate field effect transistor (DG-FET) has been modeled and the impact of strain on the I-V characteristics of CGeH channel has been examined. The bond lengths, binding and formation energies of various hydrogenated geometries of buckled germanane channel were calculated using local density approximation (LDA) with Perdew-Zunger (PZ) and generalized gradient approximation (GGA) with Perdew Burke Ernzerhof (PBE) parameterization. From four various geometries, chair like structure is found to be more stable compared to boat like obtuse, stiruup structure and table like structure. The bandgap versus width, bandgap versus strain characteristics and I-V characteristics had been analyzed at room temperature using density functional theory (DFT). Using self consistent calculation it was observed that the electronic properties of nano-ribbon is independent of length and band structure, but dependent on edge type, strain [Uni-axial (ɛ xx ), bi-axial (ɛ xx   =  ɛ yy )] and width of the ribbon. The strain engineered hydrogenated germanane (GeH) showed wide direct bandgap (2.3 eV) which could help to build low noise electronic devices that operates at high frequencies. The observed bi-axial compression has high impact on the device transport characteristics with peak to valley ratio (PVR) of 2.14 and 380% increase in peak current compared to pristine CGeH device. The observed strain in CGeH DG-FET could facilitate in designing novel multiple-logic memory devices due to multiple negative differential resistance (NDR) regions.

  5. Phase-dependent interference between frequency doubled comb lines in a χ(2) phase-matched aluminum nitride microring.

    Science.gov (United States)

    Jung, Hojoong; Guo, Xiang; Zhu, Na; Papp, Scott B; Diddams, Scott A; Tang, Hong X

    2016-08-15

    Nonlinear optical conversion with frequency combs is important for self-referencing and for generating shorter wavelength combs. Here we demonstrate efficient frequency comb doubling through the combination of second-harmonic generation (SHG) and sum-frequency generation (SFG) of an input comb with a high Q, phase-matched χ(2) microring resonator. Phase coherence of the SHG and SFG nonlinear conversion processes is confirmed by sinusoidal phase-dependent interference between frequency doubled comb lines.

  6. Frequency Characteristics of Double-Walled Carbon Nanotube Resonator with Different Length

    Directory of Open Access Journals (Sweden)

    Jun-Ha LEE

    2016-05-01

    Full Text Available In this paper, we have conducted classical molecular dynamics simulations for DWCNTs of various wall lengths to investigate their use as ultrahigh frequency nano-mechanical resonators. We sought to determine the variations in the frequency of these resonators according to changes in the DWCNT wall lengths. For a double-walled carbon nanotube resonator with a shorter inner nanotube, the shorter inner nanotube can be considered to be a flexible core, and thus, the length influences the fundamental frequency. In this paper, we analyze the variation in frequency of ultra-high frequency nano-mechnical resonators constructed from DWCNTs with different wall lengths.DOI: http://dx.doi.org/10.5755/j01.ms.22.2.12951

  7. 6.1 W single frequency laser output at 1645 nm from a resonantly pumped Er:YAG nonplanar ring oscillator.

    Science.gov (United States)

    Gao, Chunqing; Zhu, Lingni; Wang, Ran; Gao, Mingwei; Zheng, Yan; Wang, Lei

    2012-06-01

    A monolithic 1645 nm Er:YAG nonplanar ring oscillator (NPRO) resonantly pumped by a 1532 nm fiber laser is demonstrated. For reducing the energy-transfer upconversion effect, a 0.5% doped Er:YAG nonplanar crystal was used. An up to 6.1 W single frequency laser output at 1645 nm was obtained, with a slope efficiency of 55.2% and an optical efficiency of 48.0%. The linewidth of the Er:YAG NPRO was 14.4 kHz.

  8. Study of fuzzy adaptive PID controller on thermal frequency stabilizing laser with double longitudinal modes

    Science.gov (United States)

    Mo, Qingkai; Zhang, Tao; Yan, Yining

    2016-10-01

    There are contradictions among speediness, anti-disturbance performance, and steady-state accuracy caused by traditional PID controller in the existing light source systems of thermal frequency stabilizing laser with double longitudinal modes. In this paper, a new kind of fuzzy adaptive PID controller was designed by combining fuzzy PID control technology and expert system to make frequency stabilizing system obtain the optimal performance. The experiments show that the frequency stability of the designed PID controller is similar to the existing PID controller (the magnitude of frequency stability is less than 10-9 in constant temperature and 10-7 in open air). But the preheating time is shortened obviously (from 10 minutes to 5 minutes) and the anti-disturbance capability is improved significantly (the recovery time needed after strong interference is reduced from 1 minute to 10 seconds).

  9. Evaluation of magnocellular pathway abnormalities in schizophrenia: a frequency doubling technology study and clinical implications

    Directory of Open Access Journals (Sweden)

    Fabiana Benites Vaz de Lima

    2013-04-01

    Full Text Available BACKGROUND: Visual processing deficits have been reported for patients with schizophrenia. Previous studies demonstrated differences in early-stage processing of schizophrenics, although the nature, extent, and localization of the disturbance are unknown. The magnocellular and parvocellular visual pathways are associated with transient and sustained channels, but their respective contributions to schizophrenia-related visual deficits remains controversial. PURPOSE: The aim of this study was to evaluate magnocellular dysfunction in schizophrenia using frequency doubling technology. METHODS: Thirty-one patients with schizophrenia and 34 healthy volunteers were examined. Frequency doubling technology testing was performed in one session, consisting of a 15-minute screening strategy followed by the C-20 program for frequency doubling technology. RESULTS: Schizophrenic patients showed lower global mean sensitivity (30,97 ± 2,25 dB compared with controls (32,17 ± 3,08 dB, p<0.009. Although there was no difference in the delta sensitivity of hemispheres, there was a difference in sensitivity analysis of the fibers crossing the optic chiasm, with lower mean sensitivity in the patient group (28,80 dB versus controls (30,66 dB. The difference was higher in fibers that do not cross the optic chiasm, with lower mean sensitivity in patients (27,61 dB versus controls (30,26 dB, p<0.005. CONCLUSIONS: Our results suggest that there are differences between global sensitivity and fiber sensitivity measured by frequency doubling technology. The different sensitivity of fibers that do not cross the optic chiasm is consistent with most current etiological hypotheses for schizophrenia. The decreased sensitivity responses in the optic radiations may significantly contribute to research assessing early-stage visual processing deficits for patients with schizophrenia.

  10. The analgesic effect of photobiomodulation therapy (830 nm) on the masticatory muscles: a randomized, double-blind study.

    Science.gov (United States)

    Costa, Sabrina Araújo Pinho; Florezi, Giovanna Piacenza; Artes, Gisele Ebling; Costa, Jessica Ribeiro da; Gallo, Rosane Tronchin; Freitas, Patricia Moreira de; Witzel, Andrea Lusvarghi

    2017-12-18

    This study assesses the efficacy of photobiomodulation therapy (830 nm) for myalgia treatment of masticatory muscles. Sixty patients with muscular myalgia were selected and randomly allocated into 2 groups (n=30): Group A comprised patients given a placebo (control), and Group B consisted of those undergoing photobiomodulation therapy (PBMT). PBMT and placebo were applied bilaterally to specific points on the masseter and temporal muscles. Referred pain elicited by palpation and maximum mouth opening were measured before (EV1) and after (EV2) the treatments. The data were analyzed using statistical tests, considering a significance level of 5%. No significant differences in range were observed for active or passive mouth opening (p ≥ 0.05). Comparing the final outcomes (EV1-EV2) of both treatments, statistical significance was verified for total pain in the right masseter muscle (p = 0.001) and total pain (p = 0.005). In EV2, significant differences in pain reported with palpation were found between Groups A and B for the following: left posterior temporal muscle (p = 0.025), left superior masseter muscle (p = 0.036), inferior masseter muscle (p = 0.021), total pain (left side) (p = 0.009), total masseter muscle (left side) (p = 0.014), total temporal (left side) (p = 0.024), and total pain (p = 0.035). We concluded that PBMT (830 nm) reduces pain in algic points, but does not influence the extent of mouth opening in patients with myalgia.

  11. A wide range ultra-low power Phase-Locked Loop with automatic frequency setting in 130 nm CMOS technology for data serialisation

    International Nuclear Information System (INIS)

    Firlej, M.; Fiutowski, T.; Idzik, M.; Moroń, J.; Świentek, K.

    2015-01-01

    The design and measurements results of a wide frequency range ultra-low power Phase-Locked Loop (PLL) for applications in readout systems of particle physics detectors are presented. The PLL was fabricated in a 130 nm CMOS technology. To allow the implementation of different data serialisation schemes multiple division factors (6, 8, 10, 16) were implemented in the PLL feedback loop. The main PLL block—VCO works in 16 frequency ranges/modes, switched either manually or automatically. A dedicated automatic frequency mode switching circuit was developed to allow simple frequency tuning. Although the PLL was designed and simulated for a frequency range of 30 MHz–3 GHz, due to the SLVS interface limits, the measurements were done only up to 1.3 GHz. The full PLL functionality was experimentally verified, confirming a very low and frequency scalable power consumption (0.7 mW at 1 GHz)

  12. A wide range ultra-low power Phase-Locked Loop with automatic frequency setting in 130 nm CMOS technology for data serialisation

    Science.gov (United States)

    Firlej, M.; Fiutowski, T.; Idzik, M.; Moroń, J.; Świentek, K.

    2015-12-01

    The design and measurements results of a wide frequency range ultra-low power Phase-Locked Loop (PLL) for applications in readout systems of particle physics detectors are presented. The PLL was fabricated in a 130 nm CMOS technology. To allow the implementation of different data serialisation schemes multiple division factors (6, 8, 10, 16) were implemented in the PLL feedback loop. The main PLL block—VCO works in 16 frequency ranges/modes, switched either manually or automatically. A dedicated automatic frequency mode switching circuit was developed to allow simple frequency tuning. Although the PLL was designed and simulated for a frequency range of 30 MHz-3 GHz, due to the SLVS interface limits, the measurements were done only up to 1.3 GHz. The full PLL functionality was experimentally verified, confirming a very low and frequency scalable power consumption (0.7 mW at 1 GHz).

  13. 10 mJ single-frequency, injection-seeded Q-switched Er:YAG laser pumped by a 1470 nm fiber-coupled LD

    Science.gov (United States)

    Gao, C. Q.; Shi, Y.; Ye, Q.; Wang, S.; Na, Q. X.; Wang, Q.; Gao, M. W.

    2018-02-01

    A 1645 nm injection-seeded Q-switched Er:YAG laser resonantly pumped by a 1470 nm fiber-coupled laser diode is demonstrated with a non-planar ring oscillator as a seed laser to realize the single-frequency operation. The maximum output pulse energy of the laser is 10.1 mJ, corresponding to a pulse width of 205 ns at a repetition rate of 200 Hz. The half-width of the pulse spectrum is 2.44 MHz measured by a heterodyne technique. The fluctuation of the center frequency of the pulsed laser is 1.43 MHz (RMS) in 1 h. To the best of our knowledge, this is highest energy obtained from a single-frequency, injection-seeded Er:YAG laser pumped by a laser diode.

  14. Temporal structure of double plasma frequency emission of thin beam-heated plasma

    Science.gov (United States)

    Postupaev, V. V.; Burdakov, A. V.; Ivanov, I. A.; Sklyarov, V. F.; Arzhannikov, A. V.; Gavrilenko, D. Ye.; Kandaurov, I. V.; Kasatov, A. A.; Kurkuchekov, V. V.; Mekler, K. I.; Polosatkin, S. V.; Popov, S. S.; Rovenskikh, A. F.; Sudnikov, A. V.; Sulyaev, Yu. S.; Trunev, Yu. A.; Vyacheslavov, L. N.

    2013-09-01

    In the work presented here dynamics of spiky microwave emission of a beam-heated plasma near the double plasma frequency in ˜100 GHz band was studied. The plasma is heated by 80 keV, ˜2 MW, sub-ms electron beam that is injected into the multiple-mirror trap GOL-3. The beam-heated plasma diameter is of the order of the emitted wavelength. Modulation of individual emission spikes in the microwave radiation is found. The radiation dynamics observed can be attributed to a small number of compact emitting zones that are periodically distorted.

  15. Green frequency-doubled laser-beam propagation in high-temperature hohlraum plasmas.

    Science.gov (United States)

    Niemann, C; Berger, R L; Divol, L; Froula, D H; Jones, O; Kirkwood, R K; Meezan, N; Moody, J D; Ross, J; Sorce, C; Suter, L J; Glenzer, S H

    2008-02-01

    We demonstrate propagation and small backscatter losses of a frequency-doubled (2omega) laser beam interacting with inertial confinement fusion hohlraum plasmas. The electron temperature of 3.3 keV, approximately a factor of 2 higher than achieved in previous experiments with open geometry targets, approaches plasma conditions of high-fusion yield hohlraums. In this new temperature regime, we measure 2omega laser-beam transmission approaching 80% with simultaneous backscattering losses of less than 10%. These findings suggest that good laser coupling into fusion hohlraums using 2omega light is possible.

  16. Reduction of a Double Supply Frequency Pressure Pulsation in an Electro-Magnetic Pump

    International Nuclear Information System (INIS)

    Seong, Seung-Hwan; Park, Rae-Young; Lee, Tae-Ho; Kim, Seong-O

    2007-01-01

    Fast breeder reactors using sodium coolant have adopted the AC induction electro-magnetic (EM) pump as a coolant pump for a liquid metal flow. The EM pumps have some disadvantages such as a double supply frequency (DSF) pressure pulsation and so on. The DSF pressure pulsation occurs in the induction EM pump, when an alternating current is supplied to the coils. The magnetic field produced by the coils reacts with the alternating current being passed through the sodium, and then the pressure developed pulsates at twice the input frequency. The DSF pressure pulsation is dominantly affected by the disturbances of the electromagnetic force near the stator or core ends. The disturbance of the electromagnetic force can be derived the Lenz's Law which means that the opposite forces are generated when the magnetic field abruptly changed by the liquid metal flows near the stator ends. This phenomenon is called as the end effect

  17. Explicit formulation for natural frequencies of double-beam system with arbitrary boundary conditions

    Energy Technology Data Exchange (ETDEWEB)

    Mirzabeigy, Alborz; Madoliat, Reza [Iran University of Science and Technology, Narmak, Tehran (Iran, Islamic Republic of); Dabbagh, Vahid [University of Malaya, Kuala Lumpur (Malaysia)

    2017-02-15

    In this paper, free transverse vibration of two parallel beams connected through Winkler type elastic layer is investigated. Euler- Bernoulli beam hypothesis has been applied and it is assumed that boundary conditions of upper and lower beams are similar while arbitrary without any limitation even for non-ideal boundary conditions. Material properties and cross-section geometry of beams could be different from each other. The motion of the system is described by a homogeneous set of two partial differential equations, which is solved by using the classical Bernoulli-Fourier method. Explicit expressions are derived for the natural frequencies. In order to verify accuracy of results, the problem once again solved using modified Adomian decomposition method. Comparison between results indicates excellent accuracy of proposed formulation for any arbitrary boundary conditions. Derived explicit formulation is simplest method to determine natural frequencies of double-beam systems with high level of accuracy in comparison with other methods in literature.

  18. Frequency and spectrum of mutations induced by gamma irradiation in single, double and triple dwarf wheats

    International Nuclear Information System (INIS)

    Dhonukshe, B.L.

    1981-01-01

    Induced mutation studies were carried with three dwarf wheat varieties viz., ''Sonalika'', ''Chhoti Lerma'' and ''Hira'', considered to be single, double and trible dwarfs, respectively. Gamma-rays were used as a source of irradiation. Frequency of chlorophyll mutations were comparatively low and the spectrum was narrow. Chlorophyll mutations were altogether absent in the variety ''Sonalika''. A very wide spectrum of viable mutations affecting stem, leaf, ear growth habit, maturity and fertility characteristics was observed in the M 2 . The cumulative frequency of all the mutants together was quite high, which varied with the varieties. There were varietal differences in the composition and width of the spectrum induced by gamma-rays. The dwarf mutants having desirable leaf and spike characters were isolated in all the three varieties. (author)

  19. AIR FLOW AND ENVIRONMENTAL WIND VISUALIZATION USING A CW DIODE PUMPED FREQUENCY DOUBLED Nd:YAG Laser

    Directory of Open Access Journals (Sweden)

    Mircea UDREA

    2009-09-01

    Full Text Available Preliminary results obtained in developing a visualisation technique for non-invasive analysis of air flow inside INCAS subsonic wind tunnel and its appendages are presented. The visualisation technique is based on using a green light sheet generated by a continuous wave (cw longitudinally diode pumped and frequency doubled Nd:YAG laser. The output laser beam is expanded on one direction and collimated on rectangular direction. The system is tailored to the requirements of qualitative analysis and vortex tracking requirements inside the INCAS 2.5m x 2.0m subsonic wind tunnel test section, for measurements performed on aircraft models. Also the developed laser techniques is used for non-invasive air flow field analysis into environmental facilities settling room (air flow calming area. Quantitative analysis is enabled using special image processing tools upon movies and pictures obtained during the experiments. The basic experimental layout in the wind tunnel takes advantage of information obtained from the investigation of various aircraft models using the developed visualisation technique. These results are further developed using a Particle Imaging Velocimetry (PIV experimental technique.The focus is on visualisation techniques to be used for wind flow characterization at different altitudes in indus-trial and civil buildings areas using a light sheet generated by a Nd:YAG cw pumped and doubled laser at 532 nm wave-length. The results are important for prevention of biological/chemical disasters such as spreading of extremely toxic pol-lutants due to wind. Numerical simulations of wind flow and experimental visualisation results are compared. A good agreement between these results is observed.

  20. Doubling of coastal flooding frequency within decades due to sea-level rise

    Science.gov (United States)

    Vitousek, Sean; Barnard, Patrick L.; Fletcher, Charles H.; Frazer, Neil; Erikson, Li; Storlazzi, Curt D.

    2017-01-01

    Global climate change drives sea-level rise, increasing the frequency of coastal flooding. In most coastal regions, the amount of sea-level rise occurring over years to decades is significantly smaller than normal ocean-level fluctuations caused by tides, waves, and storm surge. However, even gradual sea-level rise can rapidly increase the frequency and severity of coastal flooding. So far, global-scale estimates of increased coastal flooding due to sea-level rise have not considered elevated water levels due to waves, and thus underestimate the potential impact. Here we use extreme value theory to combine sea-level projections with wave, tide, and storm surge models to estimate increases in coastal flooding on a continuous global scale. We find that regions with limited water-level variability, i.e., short-tailed flood-level distributions, located mainly in the Tropics, will experience the largest increases in flooding frequency. The 10 to 20 cm of sea-level rise expected no later than 2050 will more than double the frequency of extreme water-level events in the Tropics, impairing the developing economies of equatorial coastal cities and the habitability of low-lying Pacific island nations.

  1. Doubling of coastal flooding frequency within decades due to sea-level rise.

    Science.gov (United States)

    Vitousek, Sean; Barnard, Patrick L; Fletcher, Charles H; Frazer, Neil; Erikson, Li; Storlazzi, Curt D

    2017-05-18

    Global climate change drives sea-level rise, increasing the frequency of coastal flooding. In most coastal regions, the amount of sea-level rise occurring over years to decades is significantly smaller than normal ocean-level fluctuations caused by tides, waves, and storm surge. However, even gradual sea-level rise can rapidly increase the frequency and severity of coastal flooding. So far, global-scale estimates of increased coastal flooding due to sea-level rise have not considered elevated water levels due to waves, and thus underestimate the potential impact. Here we use extreme value theory to combine sea-level projections with wave, tide, and storm surge models to estimate increases in coastal flooding on a continuous global scale. We find that regions with limited water-level variability, i.e., short-tailed flood-level distributions, located mainly in the Tropics, will experience the largest increases in flooding frequency. The 10 to 20 cm of sea-level rise expected no later than 2050 will more than double the frequency of extreme water-level events in the Tropics, impairing the developing economies of equatorial coastal cities and the habitability of low-lying Pacific island nations.

  2. A high-finesse Fabry–Perot cavity with a frequency-doubled green laser for precision Compton polarimetry at Jefferson Lab

    Energy Technology Data Exchange (ETDEWEB)

    Rakhman, A., E-mail: rahim@ornl.gov [Syracuse University, Department of Physics, Syracuse, NY 13244 (United States); Research Accelerator Division, Spallation Neutron Source, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Hafez, M. [Old Dominion University, Applied Research Center, Norfolk, VA 23529 (United States); Nanda, S. [Thomas Jefferson National Accelerator Facility, Newport News, VA 23606 (United States); Benmokhtar, F. [Carnegie Mellon University, Department of Physics, Pittsburgh, PA 15213 (United States); Duquesne University, Pittsburgh, PA 15282 (United States); Camsonne, A. [Thomas Jefferson National Accelerator Facility, Newport News, VA 23606 (United States); Cates, G.D. [University of Virginia, Department of Physics, Charlottesville, VA 22904 (United States); Dalton, M.M. [Thomas Jefferson National Accelerator Facility, Newport News, VA 23606 (United States); University of Virginia, Department of Physics, Charlottesville, VA 22904 (United States); Franklin, G.B. [Carnegie Mellon University, Department of Physics, Pittsburgh, PA 15213 (United States); Friend, M. [Carnegie Mellon University, Department of Physics, Pittsburgh, PA 15213 (United States); High Energy Accelerator Research Organization (KEK), Tsukuba, Ibaraki (Japan); Michaels, R.W. [Thomas Jefferson National Accelerator Facility, Newport News, VA 23606 (United States); Nelyubin, V. [University of Virginia, Department of Physics, Charlottesville, VA 22904 (United States); Parno, D.S. [Carnegie Mellon University, Department of Physics, Pittsburgh, PA 15213 (United States); University of Washington, Center for Experimental Nuclear Physics and Astrophysics and Department of Physics, Seattle, WA 98195 (United States); Paschke, K.D. [University of Virginia, Department of Physics, Charlottesville, VA 22904 (United States); Quinn, B.P. [Carnegie Mellon University, Department of Physics, Pittsburgh, PA 15213 (United States); and others

    2016-06-21

    A high-finesse Fabry–Perot cavity with a frequency-doubled continuous wave green laser (532 nm) has been built and installed in Hall A of Jefferson Lab for high precision Compton polarimetry. The infrared (1064 nm) beam from a ytterbium-doped fiber amplifier seeded by a Nd:YAG nonplanar ring oscillator laser is frequency doubled in a single-pass periodically poled MgO:LiNbO{sub 3} crystal. The maximum achieved green power at 5 W infrared pump power is 1.74 W with a total conversion efficiency of 34.8%. The green beam is injected into the optical resonant cavity and enhanced up to 3.7 kW with a corresponding enhancement of 3800. The polarization transfer function has been measured in order to determine the intra-cavity circular laser polarization within a measurement uncertainty of 0.7%. The PREx experiment at Jefferson Lab used this system for the first time and achieved 1.0% precision in polarization measurements of an electron beam with energy and current of 1.06 GeV and 50 μA.

  3. 1.319 μm excited intense 800 nm frequency upconversion emission in Tm{sup 3+}-doped fluorogermanate glass

    Energy Technology Data Exchange (ETDEWEB)

    Gouveia-Neto, A. S.; Vermelho, M. V. D.; Gouveia, E. A.; Jacinto, C., E-mail: cjacinto@fis.ufal.br [Grupo de Fotônica e Fluidos Complexos, Instituto de Física, Universidade Federal de Alagoas, 57072-900 Maceió-AL (Brazil); Bueno, L. A. [Universidade de Sorocaba, 18023-000 Sorocaba-SP (Brazil)

    2015-11-23

    Generation of near-infrared light within the first biological optical window via frequency upconversion in Tm{sup 3+}-doped PbGeO{sub 3}-PbF{sub 2}-CdF{sub 2} glass excited within the second biological window at 1.319 μm is reported. The upconversion emission at 800 nm is the sole light signal observed in the entire ultraviolet-visible-near-infrared spectral region making it possible obtaining high contrast imaging. The dependence of the 800 nm signal upon the sample temperature was investigated and results showed an increase by a factor of ×2.5 in the 30–280 °C range. Generation of detectable 690 nm for temperatures above 100 °C in addition to the intense 800 nm main signal was also observed. The proposed excitation mechanism for the 800 nm thulium emitting level is assigned to a multiphonon-assisted excitation from the ground-state {sup 3}H{sub 6} to the {sup 3}H{sub 5} excited-state level, a rapid relaxation to the {sup 3}F{sub 4} level and followed by an excited-state absorption of the pump photons mediated by multiphonons connecting the {sup 3}F{sub 4} level to the {sup 3}H{sub 4} emitting level.

  4. Polarized-photon frequency filter in double-ferromagnetic barrier silicene junction

    Energy Technology Data Exchange (ETDEWEB)

    Chantngarm, Peerasak; Yamada, Kou [Domain of Mechanical Science and Technology, Graduate School of Science and Technology, Gunma University, Gunma (Japan); Soodchomshom, Bumned, E-mail: Bumned@hotmail.com [Department of Physics, Faculty of Science, Kasetsart University Bangkok 10900 (Thailand)

    2017-05-01

    We present an analytical study of effects from circularly polarized light illumination on controlling spin-valley currents in a dual ferromagnetic-gated silicene. Two different perpendicular electric fields are applied into the ferromagnetic (FM) gates and the photo-irradiated normal (NM) area between the gates. One parallel (P) and two anti-parallel (AP) configurations of exchange fields applied along with chemical potential to the gates are used in this investigation. Interestingly, the studied junction might give rise to polarized-photon frequency filter. Spin-valley filtering can be achieved at the off-resonant frequency region with appropriate direction of electric fields and the configuration of exchange fields (AP-1 or AP-2). Under the photo irradiation, this study found that tunneling magnetoresistance (TMR) is controllable to achieve giant magnetoresistance (GMR) by adjusting electric fields or chemical potentials. Our study suggests the potential of photo-sensing devices in spin-valleytronics realm. - Highlights: • Photon-frequency control of spin-valley currents in silicene is investigated. • Complete photon frequency filtering effect is predicted. • Giant magnetoresistance induced by polarized photon is also found. • The junction is applicable for photo-sensing devices in spin-valleytronics realm.

  5. Tolerance of low-frequency ultrasound sonophoresis: a double-blind randomized study on humans.

    Science.gov (United States)

    Maruani, Annabel; Vierron, Emilie; Machet, Laurent; Giraudeau, Bruno; Halimi, Jean-Michel; Boucaud, Alain

    2012-05-01

    Sonophoresis [low-frequency ultrasound (US)] has been used in animals and in vitro to investigate enhanced percutaneous absorption of drugs. No study focused on its clinical human tolerance has been published as yet. We aimed to assess the bioeffects of low-frequency US in vivo on human skin in a double-blind randomized-controlled study. We applied pulse-mode US at 36 kHz for 5 min in a step procedure of increasing dosage, from 1.57 to 3.50 W/cm(2), and placebo. The primary outcome was toxic effects of the procedure, defined as a pain score >40 on a 0-100 mm visual analogue scale or necrosis. Erythema (scored from 0 to 3 in severity) was also evaluated. The secondary outcomes were measurements of skin thickness by high-resolution skin imaging, of skin capacitance and temperature. We included 34 healthy volunteers. We found no pain score >38 and no skin necrosis with either US or placebo. Erythema was systematically observed immediately after US application, but after 1 day, we observed three cases in the knee group. The most frequent adverse effect was tinnitus. We observed no marked increase in temperature or cutaneous thickness after US or placebo. Cutaneous capacitance increased immediately after both applications. Such data demonstrating good tolerance of sonophoresis can be useful before the initiation of a clinical trial of the therapeutic use of low-frequency sonophoresis in humans. © 2011 John Wiley & Sons A/S.

  6. Double variable frequency pendulum isolator for seismic isolation of liquid storage tanks

    Energy Technology Data Exchange (ETDEWEB)

    Soni, D.P., E-mail: soni_svit@yahoo.co [Civil Engineering Department, Sardar Vallabhbhai Patel Institute of Technology, Vasad 388 306, Gujarat (India); Mistry, B.B., E-mail: bbm_7@yahoo.co.i [Engineering College, Tuwa 389 001 (India); Panchal, V.R., E-mail: vijay_svit@yahoo.co.i [Civil Engineering Department, Sardar Vallabhbhai Patel Institute of Technology, Vasad 388 306, Gujarat (India)

    2011-03-15

    Research highlights: The seismic response of liquid storage tanks isolated by the DVFPI is investigated. Four DVFPI design cases are considered by varying properties of the both surfaces. Criterion to optimize its performance is proposed based on minimum responses. Different stiffness of top and bottom surfaces optimizes the DVFPI for a slender tank. Equal stiffness of top and bottom surfaces optimizes the DVFPI for a broad tank. - Abstract: The paper describes the behaviour of liquid storage slender and broad tanks isolated by the double variable frequency pendulum isolator (DVFPI). The DVFPI is a double sliding isolation system having elliptical sliding surfaces. The geometry and coefficient of friction of top and bottom sliding surfaces can be unequal. The governing equations of motion and energy balance equation of the tank-isolation system subjected to bilateral ground excitation are derived and solved in the incremental form. In order to investigate the behaviour of the DVFPI, the response is obtained under different parametric variations for a set of 20 far-field earthquake ground motions. Four different combinations of the DVFPI design cases having different isolator geometry and coefficient friction at top and bottom sliding surfaces are studied and the criterion to optimize its performance is proposed based on minimum responses and energy quantities. Further, influences of the initial time period, coefficient of friction and frequency variation factors at the two sliding surfaces and the tank aspect ratio are investigated. It is found that the performance of the DVFPI can be optimized by designing the top sliding surface with high initial stiffness relative to the bottom one and the coefficient of friction of both sliding surfaces to be equal for a slender tank whereas both surfaces should be designed with equal initial stiffness and coefficient of friction for a broad tank.

  7. Optical properties measurement of laser coagulated tissues with double integrating sphere and inverse Monte Carlo technique in the wavelength range from 350 to 2100 nm

    Science.gov (United States)

    Honda, Norihiro; Nanjo, Takuya; Ishii, Katsunori; Awazu, Kunio

    2012-03-01

    In laser medicine, the accurate knowledge about the optical properties (absorption coefficient; μa, scattering coefficient; μs, anisotropy factor; g) of laser irradiated tissues is important for the prediction of light propagation in tissues, since the efficacy of laser treatment depends on the photon propagation within the irradiated tissues. Thus, it is likely that the optical properties of tissues at near-ultraviolet, visible and near-infrared wavelengths will be more important due to more biomedical applications of lasers will be developed. For improvement of the laser induced thermotherapy, the optical property change during laser treatment should be considered in the wide wavelength range. For estimation of the optical properties of the biological tissues, the optical properties measurement system with a double integrating sphere setup and an inverse Monte Carlo technique was developed. The optical properties of chicken muscle tissue were measured in the native state and after laser coagulation using the optical properties measurement system in the wavelength range from 350 to 2100 nm. A CO2 laser was used for laser coagulation. After laser coagulation, the reduced scattering coefficient of the tissue increased. And, the optical penetration depth decreased. For improvement of the treatment depth during laser coagulation, a quantitative procedure using the treated tissue optical properties for determination of the irradiation power density following light penetration decrease might be important in clinic.

  8. Effect of low-level laser therapy (808 nm) on markers of muscle damage: a randomized double-blind placebo-controlled trial.

    Science.gov (United States)

    Felismino, Amanda Soares; Costa, Eduardo Caldas; Aoki, Marcelo Saldanha; Ferraresi, Cleber; de Araújo Moura Lemos, Telma Maria; de Brito Vieira, Wouber Hérickson

    2014-05-01

    The aim of this randomized double-blind placebo-controlled study was to investigate the effect of low-level laser therapy (LLLT) on markers of muscle damage (creatine kinase (CK) and strength performance) in the biceps brachii. Twenty-two physically active men were randomized into two groups: placebo and laser. All volunteers were submitted to an exercise-induced muscle damage protocol for biceps brachii (biceps curl, 10 sets of 10 repetitions with load of 50% of one-repetition maximum test (1RM)). Active LLLT (808 nm; 100 mW; 35.7 W/cm(2), 357.14 J/cm(2) per point, energy of 1 J per point applied for 10 s on four points of the biceps brachii belly of each arm) or placebo was applied between the sets of the biceps curl exercise. CK activity and maximum strength performance (1RM) were measured before, immediately after, 24, 48, and 72 h after the exercise-induced muscle damage protocol. There was an increase in CK activity after the muscle damage protocol in both groups; however, this increase was attenuated in the laser group compared to the placebo group at 72 h (placebo = 841 vs. laser = 357%; p effect on the recovery of strength performance.

  9. Double-grid finite-difference frequency-domain (DG-FDFD) method for scattering from chiral objects

    CERN Document Server

    Alkan, Erdogan; Elsherbeni, Atef

    2013-01-01

    This book presents the application of the overlapping grids approach to solve chiral material problems using the FDFD method. Due to the two grids being used in the technique, we will name this method as Double-Grid Finite Difference Frequency-Domain (DG-FDFD) method. As a result of this new approach the electric and magnetic field components are defined at every node in the computation space. Thus, there is no need to perform averaging during the calculations as in the aforementioned FDFD technique [16]. We formulate general 3D frequency-domain numerical methods based on double-grid

  10. Suppressed power saturation due to optimized optical confinement in 9xx nm high-power diode lasers that use extreme double asymmetric vertical designs

    Science.gov (United States)

    Kaul, T.; Erbert, G.; Maaßdorf, A.; Knigge, S.; Crump, P.

    2018-03-01

    Broad area lasers with novel extreme double asymmetric structure (EDAS) vertical designs featuring increased optical confinement in the quantum well, Γ, are shown to have improved temperature stability without compromising series resistance, internal efficiency or losses. Specifically, we present here vertical design considerations for the improved continuous wave (CW) performance of devices operating at 940 nm, based on systematically increasing Γ from 0.26% to 1.1%, and discuss the impact on power saturation mechanisms. The results indicate that key power saturation mechanisms at high temperatures originate in high threshold carrier densities, which arise in the quantum well at low Γ. The characteristic temperatures, T 0 and T 1, are determined under short pulse conditions and are used to clarify the thermal contribution to power limiting mechanisms. Although increased Γ reduces thermal power saturation, it is accompanied by increased optical absorption losses in the active region, which has a significant impact on the differential external quantum efficiency, {η }{{diff}}. To quantify the impact of internal optical losses contributed by the quantum well, a resonator length-dependent simulation of {η }{{diff}} is performed and compared to the experiment, which also allows the estimation of experimental values for the light absorption cross sections of electrons and holes inside the quantum well. Overall, the analysis enables vertical designs to be developed, for devices with maximized power conversion efficiency at high CW optical power and high temperatures, in a trade-off between absorption in the well and power saturation. The best balance to date is achieved in devices using EDAS designs with {{Γ }}=0.54 % , which deliver efficiencies of 50% at 14 W optical output power at an elevated junction temperature of 105 °C.

  11. Glaucoma progression detection with frequency doubling technology (FDT) compared to standard automated perimetry (SAP) in the Groningen Longitudinal Glaucoma Study

    NARCIS (Netherlands)

    Wesselink, Christiaan; Jansonius, Nomdo M.

    Purpose: To determine the usefulness of frequency doubling perimetry (FDT) for progression detection in glaucoma, compared to standard automated perimetry (SAP). Methods: Data were used from 150 eyes of 150 glaucoma patients from the Groningen Longitudinal Glaucoma Study. After baseline, SAP was

  12. Role of frequency doubling technology perimetry in screening of diabetic retinopathy.

    Directory of Open Access Journals (Sweden)

    Parikh Rajul

    2006-01-01

    Full Text Available Purpose: To study the ability of frequency-doubling technology perimetry (FDT to detect sight-threatening diabetic retinopathy. Method: Fifty-eight eyes of fifty-eight patients with established diagnosis of diabetes mellitus with diabetic retinopathy, fifty-five eyes of fifty-five diabetic patients without retinopathy, and forty-one eyes of forty-one normals underwent FDT and dilated stereo-biomicroscopic fundus examination. The sensitivity and specificity of FDT in identification of "sight-threatening retinopathy" (severe and very severe nonproliferative diabetic retinopathy and proliferative diabetic retinopathy and clinically significant macular edema (CSME were determined. Results: For the detection of sight-threatening retinopathy, two abnormal adjacent points depressed to any level on the 20-1 screening program had a sensitivity of 90.5% and specificity of 97.6%. At (assuming a 10% prevalence of sight-threatening retinopathy in a diabetic clinic, two abnormal adjacent points anywhere in the field depressed to any level has a positive predictive value (PPV of 48% with a negative predictive value of 98.8%. Sensitivity and specificity for the detection of CSME was poor. Conclusions: The 20-1 screening program of the FDT is useful in the detection of sight-threatening diabetic retinopathy (PPV 48%. A normal 20-1 test rules out sight-threatening retinopathy. FDT was not useful in the detection of CSME.

  13. Simultaneous Stabilization of Gyrotron Frequency and Power by PID Double Feedback Control on the Acceleration and Anode Voltages

    Science.gov (United States)

    Khutoryan, E. M.; Idehara, T.; Kuleshov, A. N.; Tatematsu, Y.; Yamaguchi, Y.; Matsuki, Y.; Fujiwara, T.

    2017-07-01

    In this paper, we present the results of simultaneous stabilization of both the frequency and the output power by a double PID feedback control on the acceleration and anode voltages in the 460-GHz gyrotron FU CW GVI, also known as "Gyrotron FU CW GO-1" (according to the nomenclature adopted at Osaka University). The approach used in the experiments is based on the modulation of the cyclotron frequency and the pitch factor (velocity ratio) of the electron beam by varying the acceleration and the anode voltages, respectively. In a long-term experiment, the frequency and power stabilities were made to be better than ±10-6 and ±1%, respectively.

  14. Low frequency noise assessment in n- and p-channel sub-10 nm triple-gate FinFETs: Part I: Theory and methodology

    Science.gov (United States)

    Boudier, D.; Cretu, B.; Simoen, E.; Carin, R.; Veloso, A.; Collaert, N.; Thean, A.

    2017-02-01

    The transfer characteristic at room temperature of FinFETs processed for sub-10 nm technologies could always be explained by solving Poisson equation throughout the channel - dielectric interface. Various methods for the MOSFET parameters estimation are proposed in the literature. In this paper, the electrical parameters extraction technique based on the Y-function methodology is reminded. Low frequency noise is presented considering three major noise sources: 1/f noise associated to carrier trapping-detrapping in the gate oxide, channel carrier mobility fluctuations and generation-recombination noise related to traps located in the depletion zone of the device. Theory and methodology in order to identify the 1/f noise mechanism and to have information of the process induced traps in the silicon film using the noise spectroscopy technique are revisited.

  15. Sum Frequency Generation Vibrational Spectroscopy and Kinetic Study of 2-Methylfuran and 2,5-Dimethylfuran Hydrogenation over 7 nm Platinum Cubic Nanoparticles

    KAUST Repository

    Aliaga, Cesar

    2011-04-28

    Sum frequency generation vibrational spectroscopy and kinetic measurements obtained from gas chromatography were used to study the adsorption and hydrogenation of 2-methylfuran (MF) and 2,5-dimethylfuran (DMF) over cubic Pt nanoparticles of 7 nm average size, synthesized by colloidal methods and cleaned by ultraviolet light and ozone treatment. Reactions carried out at atmospheric pressure in the temperature range of 20-120 °C produced dihydro and tetrahydro species, as well as ring-opening products (alcohols) and ring-cracking products, showing high selectivity toward ring opening throughout the entire temperature range. The aromatic rings (MF and DMF) adsorbed parallel to the nanoparticle surface. Results yield insight into various surface reaction intermediates and the reason for the significantly lower selectivity for ring cracking in DMF hydrogenation compared to MF hydrogenation. © 2011 American Chemical Society.

  16. Surprising Performance for Vibrational Frequencies of the Distinguishable Clusters with Singles and Doubles (DCSD) and MP2.5 Approximations

    OpenAIRE

    Kesharwani, Manoj K.; Sylvetsky, Nitai; Martin, Jan M. L.

    2017-01-01

    We show that the DCSD (distinguishable clusters with all singles and doubles) correlation method permits the calculation of vibrational spectra at near-CCSD(T) quality but at no more than CCSD cost, and with comparatively inexpensive analytical gradients. For systems dominated by a single reference configuration, even MP2.5 is a viable alternative, at MP3 cost. MP2.5 performance for vibrational frequencies is comparable to double hybrids such as DSD-PBEP86-D3BJ, but without resorting to empir...

  17. Combining Frequency Doubling Technology Perimetry and Scanning Laser Polarimetry for Glaucoma Detection.

    Science.gov (United States)

    Mwanza, Jean-Claude; Warren, Joshua L; Hochberg, Jessica T; Budenz, Donald L; Chang, Robert T; Ramulu, Pradeep Y

    2015-01-01

    To determine the ability of frequency doubling technology (FDT) and scanning laser polarimetry with variable corneal compensation (GDx-VCC) to detect glaucoma when used individually and in combination. One hundred ten normal and 114 glaucomatous subjects were tested with FDT C-20-5 screening protocol and the GDx-VCC. The discriminating ability was tested for each device individually and for both devices combined using GDx-NFI, GDx-TSNIT, number of missed points of FDT, and normal or abnormal FDT. Measures of discrimination included sensitivity, specificity, area under the curve (AUC), Akaike's information criterion (AIC), and prediction confidence interval lengths. For detecting glaucoma regardless of severity, the multivariable model resulting from the combination of GDx-TSNIT, number of abnormal points on FDT (NAP-FDT), and the interaction GDx-TSNIT×NAP-FDT (AIC: 88.28, AUC: 0.959, sensitivity: 94.6%, specificity: 89.5%) outperformed the best single-variable model provided by GDx-NFI (AIC: 120.88, AUC: 0.914, sensitivity: 87.8%, specificity: 84.2%). The multivariable model combining GDx-TSNIT, NAP-FDT, and interaction GDx-TSNIT×NAP-FDT consistently provided better discriminating abilities for detecting early, moderate, and severe glaucoma than the best single-variable models. The multivariable model including GDx-TSNIT, NAP-FDT, and the interaction GDx-TSNIT×NAP-FDT provides the best glaucoma prediction compared with all other multivariable and univariable models. Combining the FDT C-20-5 screening protocol and GDx-VCC improves glaucoma detection compared with using GDx or FDT alone.

  18. Double-wavelet approach to study frequency and amplitude modulation in renal autoregulation

    DEFF Research Database (Denmark)

    Sosnovtseva, Olga; Pavlov, A.N.; Mosekilde, Erik

    2004-01-01

    Biological time series often display complex oscillations with several interacting rhythmic components. Renal autoregulation, for instance, involves at least two separate mechanisms both of which can produce oscillatory variations in the pressures and flows of the individual nephrons. Using doubl...

  19. Absorption Measurements of Periodically Poled Potassium Titanyl Phosphate (PPKTP at 775 nm and 1550 nm

    Directory of Open Access Journals (Sweden)

    Jessica Steinlechner

    2013-01-01

    Full Text Available The efficient generation of second-harmonic light and squeezed light requires non-linear crystals that have low absorption at the fundamental and harmonic wavelengths. In this work the photo-thermal self-phase modulation technique is exploited to measure the absorption coefficient of periodically poled potassium titanyl phosphate (PPKTP at 1,550 nm and 775 nm. Themeasurement results are (84±40 ppm/cmand (127±24 ppm/cm, respectively. We conclude that the performance of state-of-the-art frequency doubling and squeezed light generation in PPKTP is not limited by absorption.

  20. MOSFET technologies for double-pole four-throw radio-frequency switch

    CERN Document Server

    Srivastava, Viranjay M

    2014-01-01

    This book provides analysis and discusses the design of various MOSFET technologies which are used for the design of Double-Pole Four-Throw (DP4T) RF switches for next generation communication systems. The authors discuss the design of the (DP4T) RF switch by using the Double-Gate (DG) MOSFET, as well as the Cylindrical Surrounding double-gate (CSDG) MOSFET.  The effect of HFO2 (high dielectric material) in the design of DG MOSFET and CSDG MOSFET  is also explored. Coverage includes comparison of Single-gate MOSFET and Double-gate MOSFET switching parameters, as well as testing of MOSFETs parameters using image acquisition.  ·         Provides a single-source reference to the latest technologies for the design of Double-gate MOSFET, Cylindrical Surrounding double-gate MOSFET and HFO2 based MOSFET; ·         Explains the design of RF switches using the technologies presented and simulates switches; ·         Verifies parameters and discusses feasibility of devices and switches.

  1. Nuclear magnetic resonance studies of half-integer quadrupolar nuclei : sensitivity enhancements using double frequency sweeps

    NARCIS (Netherlands)

    Iuga, Dinu

    2003-01-01

    Exploiting adiabatic passages of the spin transitions, this thesis reports sensitivity enhancements of the MAS and MQMAS experiments on half-integer quadrupolar nuclei. The processes governing frequency sweeping are described. During such experiments the irradiation frequency sweeps through the

  2. Realization of a frequency standard at 778 nm: absolute frequency measurement of the 2S-8S/D transitions in hydrogen and deuterium and determination of the Rydberg constant; Realisation d'un etalon de frequence a 778 nm: mesure absolue des frequences 2S-8S/D des atomes d'hydrogene et de deuterium et determination de la constante de rydberg

    Energy Technology Data Exchange (ETDEWEB)

    Beauvoir, B. de

    1996-12-15

    The purpose of this work is to design a 778 nm standard laser for performing an absolute measurement of 2S-8S/D frequencies of hydrogen and deuterium atoms. This frequency calibration is based on a 5S-5D two-photon transition of the rubidium atom. Metrological performance of this laser is 10 times as good as that of He-Ne laser calibrated on iodine. It has been shown that the passage of a laser radiation through an optic fiber does not deteriorate its metrological properties. 2S-8S/8D transitions have been excited in an atomic jet by a titanium-sapphire laser. Spurious effects can shift and broaden lines. In order to prevent these effects, a theoretical line has been shaped and adjusted on experimental signals. The frequency comparison between the excitation laser and the standard laser has led to the measurement of the absolute frequency of the line concerned. The value of the Rydberg constant has been deduced: R{sub {infinity}} = 109737.3156859 (10) cm{sup -1}. The comparison of experimental data between deuterium and hydrogen has allowed us to determine the value of the Lamb shift of the 2S state of deuterium: L(2S-2P) = 1059,230 (9) MHz.

  3. Compact, highly efficient, single-frequency 25W, 2051nm Tm fiber-based MOPA for CO2 trace-gas laser space transmitter

    Science.gov (United States)

    Engin, Doruk; Chuang, Ti; Litvinovitch, Slava; Storm, Mark

    2017-08-01

    Fibertek has developed and demonstrated an ideal high-power; low-risk; low-size, weight, and power (SWaP) 2051 nm laser design meeting the lidar requirements for satellite-based global measurement of carbon dioxide (CO2). The laser design provides a path to space for either a coherent lidar approach being developed by NASA Jet Propulsion Laboratory (JPL)1,2 or an Integrated Path Differential Lidar (IPDA) approach developed by Harris Corp using radio frequency (RF) modulation and being flown as part of a NASA Earth Venture Suborbital Mission—NASA's Atmospheric Carbon and Transport - America.3,4 The thulium (Tm) fiber laser amplifies a architecture, and design margins can support a coherent or IPDA lidar 10-year space mission. With follow-on funding Fibertek can adapt an existing space-based Technology Readiness Level 6 (TRL-6), 20 W erbium fiber laser package for this Tm design and enable a near-term space mission with an electrical-to-optical (e-o) efficiency of sustains its highly efficient operation for a temperature range of 5-40°C. The absence of stimulated Brillouin scattering (SBS) for the narrow linewidth amplification shows promise for further power scaling.

  4. Intense Red-Emitting Upconversion Nanophosphors (800 nm-Driven) with a Core/Double-Shell Structure for Dual-Modal Upconversion Luminescence and Magnetic Resonance in Vivo Imaging Applications.

    Science.gov (United States)

    Hong, A-Ra; Kim, Youngsun; Lee, Tae Sup; Kim, Sehoon; Lee, Kwangyeol; Kim, Gayoung; Jang, Ho Seong

    2018-04-18

    In this study, intense single-band red-emitting upconversion nanophosphors (UCNPs) excited with 800 nm near-infrared (NIR) light are reported. When a NaYF 4 :Nd,Yb active-shell is formed on the 12.7 nm sized NaGdF 4 :Yb,Ho,Ce UCNP core, the core/shell (C/S) UCNPs show tunable emission from green to red, depending on the Ce 3+ concentration under excitation with 800 nm NIR light. Ce 3+ -doped C/S UCNPs (30 mol %) exhibit single-band red emission peaking at 644 nm via a 5 F 5 → 5 I 8 transition of Ho 3+ . A high Nd 3+ concentration in the shell results in strong absorption at around 800 nm NIR light, even though the shell thickness is not large, and small-sized C/S UCNPs (16.3 nm) emit bright red light under 800 nm excitation. The formation of a thin NaGdF 4 shell on the C/S UCNPs further enhances the upconversion (UC) luminescence and sub-20 nm sized core/double-shell (C/D-S) UCNPs exhibit 2.8 times stronger UC luminescence compared with C/S UCNPs. Owing to the strong UC luminescence intensity and Gd 3+ ions on the surface of nanocrystals, they can be applied as a UC luminescence imaging agent and a T 1 contrast agent for magnetic resonance (MR) imaging. In vivo UC luminescence and high-contrast MR images are successfully obtained by utilizing the red-emitting C/D-S UCNPs.

  5. 5.7  W cw single-frequency laser at 671  nm by single-pass second harmonic generation of a 17.2  W injection-locked 1342  nm Nd : YVO4 ring laser using periodically poled MgO : LiNbO3.

    Science.gov (United States)

    Koch, Peter; Ruebel, Felix; Bartschke, Juergen; L'huillier, Johannes A

    2015-11-20

    We demonstrate a continuous wave single-frequency laser at 671.1 nm based on a high-power 888 nm pumped Nd:YVO4 ring laser at 1342.2 nm. Unidirectional operation of the fundamental ring laser is achieved with the injection-locking technique. A Nd:YVO4 microchip laser serves as the injecting seed source, providing a tunable single-frequency power of up to 40 mW. The ring laser emits a single-frequency power of 17.2 W with a Gaussian beam profile and a beam propagation factor of M2beam profile and a beam propagation factor of M2lasers. This work opens possibilities in cold atoms experiments with lithium, allowing the use of larger ensembles in magneto-optical traps or higher diffraction orders in atomic beam interferometers.

  6. Modulation of Frequency Doubled DFB-Tapered Diode Lasers for Medical Treatment

    DEFF Research Database (Denmark)

    Christensen, Mathias; Hansen, Anders Kragh; Noordegraaf, Danny

    2017-01-01

    The use of visible lasers for medical treatments is on the rise, and together with this comes higher expectations for the laser systems. For many medical treatments, such as ophthalmology, doctors require pulse on demand operation together with a complete extinction of the light between pulses. We...... have demonstrated power modulation from 0.1 Hz to 10 kHz at 532 nm with a modulation depth above 97% by wavelength detuning of the laser diode. The laser diode is a 1064 nm monolithic device with a distributed feedback (DFB) laser as the master oscillator (MO), and a tapered power amplifier (PA...

  7. Double Pass 595?nm pulsed dye laser at a 6 minute interval for the treatment of port-wine stains is not more effective than single pass

    NARCIS (Netherlands)

    Peters, M. A. D.; van Drooge, A. M.; Wolkerstorfer, A.; van Gemert, M. J. C.; van der Veen, J. P. W.; Bos, J. D.; Beek, J. F.

    2012-01-01

    Background Pulsed dye laser (PDL) is the first choice for treatment of port wine stains (PWS). However, outcome is highly variable and only a few patients achieve complete clearance. The objective of the study was to compare efficacy and safety of single pass PDL with double pass PDL at a 6 minute

  8. Raman scattering of a photon with frequency doubling by a channelled positron

    Energy Technology Data Exchange (ETDEWEB)

    Kalashnikov, N P [National Research Nuclear University ' ' MEPhI' ' (Russian Federation); Krokhin, O N [P N Lebedev Physics Institute, Russian Academy of Sciences, Moscow (Russian Federation)

    2014-12-31

    We have analysed the possibility of appearance of anti-Stokes lines in the spectrum of Raman scattering of a photon by a 'quasi-bound' charged particle in the regime of planar (axial) channelling. It is shown that radiation may emerge at the frequency, which is a combination of the incident photon frequency ω{sub 0} and transition frequency ω{sub i} in the transverse quantised motion of a channelled particle: ω = ω{sub 0} ± 2γ{sup 2}ω{sub i}, where γ is the relativistic (Lorentz) factor of a channelled particle. (nonlinear optical phenomena)

  9. A Frequency-Domain Adaptive Filter (FDAF) Prediction Error Method (PEM) Framework for Double-Talk-Robust Acoustic Echo Cancellation

    DEFF Research Database (Denmark)

    Gil-Cacho, Jose M.; van Waterschoot, Toon; Moonen, Marc

    2014-01-01

    In this paper, we propose a new framework to tackle the double-talk (DT) problem in acoustic echo cancellation (AEC). It is based on a frequency-domain adaptive filter (FDAF) implementation of the so-called prediction error method adaptive filtering using row operations (PEM-AFROW) leading...... to the FDAF-PEM-AFROW algorithm. We show that FDAF-PEM-AFROW is by construction related to the best linear unbiased estimate (BLUE) of the echo path. We depart from this framework to show an improvement in performance with respect to other adaptive filters minimizing the BLUE criterion, namely the PEM...

  10. Glaucoma progression detection with frequency doubling technology (FDT) compared to standard automated perimetry (SAP) in the Groningen Longitudinal Glaucoma Study.

    Science.gov (United States)

    Wesselink, Christiaan; Jansonius, Nomdo M

    2017-09-01

    To determine the usefulness of frequency doubling perimetry (FDT) for progression detection in glaucoma, compared to standard automated perimetry (SAP). Data were used from 150 eyes of 150 glaucoma patients from the Groningen Longitudinal Glaucoma Study. After baseline, SAP was performed approximately yearly; FDT every other year. First and last visit had to contain both tests. Using linear regression, progression velocities were calculated for SAP (Humphrey Field Analyzer) mean deviation (MD) and FDT MD and the number of test locations with a total deviation probability below p glaucoma progression in patients who cannot perform SAP reliably. © 2017 The Authors Ophthalmic & Physiological Optics © 2017 The College of Optometrists.

  11. Double Pass 595 nm Pulsed Dye Laser Does Not Enhance the Efficacy of Port Wine Stains Compared with Single Pass: A Randomized Comparison with Histological Examination.

    Science.gov (United States)

    Yu, Wenxin; Zhu, Jiafang; Wang, Lizhen; Qiu, Yajing; Chen, Yijie; Yang, Xi; Chang, Lei; Ma, Gang; Lin, Xiaoxi

    2018-03-27

    To compare the efficacy and safety of double-pass pulsed dye laser (DWL) and single-pass PDL (SWL) in treating virgin port wine stain (PWS). The increase in the extent of vascular damage attributed to the use of double-pass techniques for PWS remains inconclusive. A prospective, side-by-side comparison with a histological study for virgin PWS is still lacking. Twenty-one patients (11 flat PWS, 10 hypertrophic PWS) with untreated PWS underwent 3 treatments at 2-month intervals. Each PWS was divided into three treatment sites: SWL, DWL, and untreated control. Chromametric and visual evaluation of the efficacy and evaluation of side effects were conducted 3 months after final treatment. Biopsies were taken at the treated sites immediately posttreatment. Chromametric and visual evaluation suggested that DWL sites showed no significant improvement compared with SWL (p > 0.05) in treating PWS. The mean depth of photothermal damage to the vessels was limited to a maximum of 0.36-0.41 mm in both SWL and DWL sides. Permanent side effects were not observed in any patients. Double-pass PDL does not enhance PWS clearance. To improve the clearance of PWS lesions, either the depth of laser penetration should be increased or greater photothermal damage to vessels should be generated.

  12. Characterization of fast acoustic wave propagation using OFDR with double interrogation and frequency tracking

    Science.gov (United States)

    Gabai, Haniel; Eyal, Avishay

    2014-05-01

    A highly sensitive OFDR system capable of detecting and tracking fast acoustic wave propagation is described. The system was tested by dropping a screw (50gr) and a paperclip (impact of the screw led to a transient shift in the frequency of the interrogating light which corrupted the observed response. By tracking the beat frequencies of predefined reflectors and extracting their amplitudes significant improvement in the system's output was obtained.

  13. Comparison of Molecular Iodine Spectral Properties at 514.7 and 532 nm Wavelengths

    Directory of Open Access Journals (Sweden)

    Hrabina J.

    2014-08-01

    Full Text Available We present results of investigation and comparison of spectral properties of molecular iodine transitions in the spectral region of 514.7 nm that are suitable for laser frequency stabilization and metrology of length. Eight Doppler-broadened transitions that were not studied in detail before were investigated with the help of frequency doubled Yb-doped fiber laser, and three of the most promising lines were studied in detail with prospect of using them in frequency stabilization of new laser standards. The spectral properties of hyperfine components (linewidths, signal-to-noise ratio were compared with transitions that are well known and traditionally used for stabilization of frequency doubled Nd:YAG laser at the 532 nm region with the same molecular iodine absorption. The external frequency doubling arrangement with waveguide crystal and the Yb-doped fiber laser is also briefly described together with the observed effect of laser aging.

  14. Design and Analysis of Double-Gate MOSFETs for Ultra-Low Power Radio Frequency Identification (RFID: Device and Circuit Co-Design

    Directory of Open Access Journals (Sweden)

    Tony T. Kim

    2011-07-01

    Full Text Available Recently, double-gate MOSFETs (DGMOSFETs have been shown to be more optimal for ultra-low power circuit design due to the improved subthreshold slope and the reduced leakage current compared to bulk CMOS. However, DGMOSFETs for subthreshold circuit design have not been much explored in comparison to those for strong inversion-based design. In this paper, various configurations of DGMOSFETs, such as tied/independent gates and symmetric/asymmetric gate oxide thickness are explored for ultra-low power and high efficient radio frequency identification (RFID design. Comparison of bulk CMOS with DGMOSFETs has been conducted in ultra-low power subthreshold digital logic design and rectifier design, emphasizing the scope of the nano-scale DGMOSFET technology for future ultra-low power systems. The DGMOSFET-based subthreshold logic improves energy efficiency by more than 40% compared to the bulk CMOS-based logic at 32 nm. Among the various DGMOSFET configurations for RFID rectifiers, symmetric tied-gate DGMOSFET has the best power conversion efficiency and the lowest power consumption.

  15. Local cooling effect on perforation rates comparing the 980-1470 nm laser wavelengths used with endovenous laser ablation: double blind in vitro experimental study.

    Science.gov (United States)

    Tarhan, I A; Dumantepe, M; Yurdakul, I; Kehlibar, T; Ozler, A

    2014-03-01

    Endovenous laser treatment (EVLA) is fast gaining acceptance as an alternative to open surgery for the treatment of saphenous vein incompetence. The method of action of these techniques is based on heat, making tumescence anaesthesia necessity. Heat-induced complications may occur with inadequate application of tumescent anaesthesia. Our hypothesis was, local cooling effect of tumescent anaesthesia on tunica adventitia might be kept undamaged from disruption due to the thermal injury. We experimented with two popular laser wavelengths (980 and 1470 nm) and with two different thermal media (+4 and +24) in vitro for perforation. Twenty different 12 cm length vein pieces were numbered randomly to set up four groups of the experiment. Endovenous laser procedures were applied in same manner in a unique design test tube with same energy density per pieces on same duration (10 W/second) (linear endovenous energy density 60 J/cm). Procedure video was recorded for macroscopic perforations. All postprocedure vein segments were examined microscopically. Activities of both wavelengths were much better in cold medium (P laser was better than that of 980 nm in cold environment (P = 0.0136). It can be commented that reducing the ambient temperature is more beneficial than modifying the laser wavelength on perforation rates. Therefore we suppose tumescent anaesthesia temperature is effective on perforation independently from the wavelengths or type of the laser fibre.

  16. High-power actively Q-switched single-mode 1342 nm Nd:YVO4 ring laser, injection-locked by a cw single-frequency microchip laser.

    Science.gov (United States)

    Koch, Peter; Bartschke, Juergen; L'huillier, Johannes A

    2015-11-30

    In this paper we report on the realization of a single-mode Q-switched Nd:YVO4 ring laser at 1342 nm. Unidirectional and single-mode operation of the ring laser is achieved by injection-locking with a continuous wave Nd:YVO4 microchip laser, emitting a single-frequency power of up to 40 mW. The ring laser provides a single-mode power of 13.9 W at 10 kHz pulse repetition frequency with a pulse duration of 18.2 ns and an excellent beam quality (M2 laser, a power of 8.7 W at 671 nm with a pulse duration of 14.8 ns and a beam propagation factor of M2 < 1.1 is obtained. The 671 nm radiation features a long-term spectral width of 75 MHz.

  17. Fabrication and stability of fiber bragg gratings for WDM applications using a 266 nm cw-laser

    DEFF Research Database (Denmark)

    Deyerl, Hans-Jürgen; Sørensen, Henrik Rokkjær; Jensen, Jesper Bo Damm

    2003-01-01

    Diode pumped continuous wave all solid state UV-lasers operating at 266 nm offer an interesting alternative to frequency doubled argon ion lasers. We compare photosensitivity, UV-writing of Bragg gratings and thermal decay at 244, 257 and 266 nm....

  18. Device and circuit analysis of a sub 20 nm double gate MOSFET with gate stack using a look-up-table-based approach

    Science.gov (United States)

    Chakraborty, S.; Dasgupta, A.; Das, R.; Kar, M.; Kundu, A.; Sarkar, C. K.

    2017-12-01

    In this paper, we explore the possibility of mapping devices designed in TCAD environment to its modeled version developed in cadence virtuoso environment using a look-up table (LUT) approach. Circuit simulation of newly designed devices in TCAD environment is a very slow and tedious process involving complex scripting. Hence, the LUT based modeling approach has been proposed as a faster and easier alternative in cadence environment. The LUTs are prepared by extracting data from the device characteristics obtained from device simulation in TCAD. A comparative study is shown between the TCAD simulation and the LUT-based alternative to showcase the accuracy of modeled devices. Finally the look-up table approach is used to evaluate the performance of circuits implemented using 14 nm nMOSFET.

  19. Conversion frequence

    International Nuclear Information System (INIS)

    Sauteret, C.

    1987-03-01

    The experimental evidence of short wavelength for laser inertial confinement has strongly increased the interest in high efficiency harmonic conversion of powerful Nd: glass lasers. This work describes our high power harmonic conversion experiments performed using the same laser apparatus for doubling, tripling the three high power 1064 nm P102, OCTAL and PHEBUS lasers. In addition to the understanding the physics of harmonic conversion, this work includes the basic concepts allows us to improve the technique such as non colinear schemes, to extend this method to other frequencies (fourth generation) and to predict some physical limits [fr

  20. A practical double-sided frequency selective surface for millimeter-wave applications

    Science.gov (United States)

    Mohyuddin, Wahab; Woo, Dong Sik; Choi, Hyun Chul; Kim, Kang Wook

    2018-02-01

    Analysis, design, and implementation of a practical, high-rejection frequency selective surface (FSS) are presented in this paper. An equivalent circuit model is introduced for predicting the frequency response of the FSS. The FSS consists of periodic square loop structures fabricated on both sides of the thin dielectric substrate by using the low-cost chemical etching technique. The proposed FSS possesses band-stop characteristics and is implemented to suppress the 170 GHz signal with attenuation of more than 45 dB with insensitivity to an angle of incident plane wave over 20°. Good agreement is observed among calculated, simulated, and measured results. The proposed FSS filter can be used in various millimeter-wave applications such as the protection of imaging diagnostic systems from high spurious input power.

  1. [Venous leg ulcers: no improvement of wound healing with 685-nm low level laser therapy. Randomised, placebo-controlled, double-blind study].

    Science.gov (United States)

    Kokol, R; Berger, C; Haas, J; Kopera, D

    2005-06-01

    Venous leg ulcers (ulcera crurum venosa) are frequently seen in elderly patients. It has been suggested that low level laser irradiation has a biostimulative and wound healing effect; however, this has not yet been clinically verified by controlled studies. The difference in size reduction of leg ulcers with and without low level laser or placebo laser treatment was measured in 44 patients randomised into two treatment groups (685-nm low level laser and placebo laser) or a control group which served to quantify the effect of laser application. All patients received standardized wound care. The aim of the study was to compare the effectiveness of low level laser irradiation with that of a placebo "light source". The size of the ulcers was planimetrically measured at baseline (day 1), at the end of therapy (day 28) and 2 months later (day 90). The difference in wound size was evaluated. There were no statistically significant differences in reduction of wound size between the three groups, thus suggesting that low level laser light does not have any stimulatory effect on wound healing in ulcera crurum venosa.

  2. 3.5 W of diffraction-limited green light at 515 nm from SHG of a single-frequency tapered diode laser

    DEFF Research Database (Denmark)

    Jensen, Ole Bjarlin; Hansen, Anders Kragh; Müller, André

    2017-01-01

    Multi-Watt efficient compact green laser sources are required for a number of applications e.g. within biophotonics, laser pumping and laser displays. We present generation of 3.5 W of diffraction-limited green light at 515 nm by second harmonic generation (SHG) of a tapered diode laser, itself...

  3. Effect of 635nm Low-level Laser Therapy on Upper Arm Circumference Reduction: A Double-blind, Randomized, Sham-controlled Trial.

    Science.gov (United States)

    Nestor, Mark S; Zarraga, Matthew B; Park, Hyunhee

    2012-02-01

    To assess the safety and efficacy of low-level laser therapy as a noninvasive method for reducing upper arm circumference. Randomized, double-blind study whereby healthy subjects (N=40) with a body mass index of 20 to 35kg/m(2) received three 20-minute low-level laser therapy (N=20) or sham treatments (N=20) each week for two weeks. Upper arm circumference was measured after three and six treatments and two weeks post-treatment. Primary success criterion was the proportion of subjects achieving a combined reduction in arm circumference of ≥1.25cm measured at three equally spaced points between the elbow and the shoulder. Secondary outcomes included total measurement change at each time point and subjective satisfaction ratings. After six treatments, the low-level laser therapy group showed a combined reduction in arm circumference of 3.7cm versus 0.2cm in the sham treatment group (plow-level laser therapy group (N=12; 60%) achieved ≥1.5cm total decrease in upper arm circumference versus sham-treated subjects (N=0; 0%) (pLow-level laser therapy treatment resulted in a combined reduction in arm circumference of 2.2cm after three treatments and 3.7cm after six treatments (for each, plow-level laser therapy treatment group were satisfied with their results (pupper arm appearance improved (plow-level laser therapy is safe, painless, and effective in reducing upper arm circumference and is associated with a high degree of subject satisfaction.

  4. The double-resonance enhancement of stimulated low-frequency Raman scattering in silver-capped nanodiamonds

    Science.gov (United States)

    Baranov, A. N.; Butsen, A. V.; Ionin, A. A.; Ivanova, A. K.; Kuchmizhak, A. A.; Kudryashov, S. I.; Kudryavtseva, A. D.; Levchenko, A. O.; Rudenko, A. A.; Saraeva, I. N.; Strokov, M. A.; Tcherniega, N. V.; Zayarny, D. A.

    2017-09-01

    Hybrid plasmonic-dielectric nano- and (sub)microparticles exhibit magnetic and electrical dipolar Mie-resonances, which makes them useful as efficient basic elements in surface-enhanced spectroscopy, non-linear light conversion and nanoscale light control. We report the stimulated low-frequency Raman scattering (SLFRS) of a nanosecond ruby laser radiation (central wavelength λ = 694.3 nm (full-width at half-maximum ≈ 0.015 cm-1), gaussian 1/e-intensity pulsewidth τ ≈ 20 ns, TEM00-mode pulse energy Emax ≈ 0.3 J) in nanodiamond (R ≈ 120 nm) hydrosols, induced via optomechanical coherent excitation of fundamental breathing eigen-modes, and the two-fold enhancement of SLFRS in Ag-decorated nanodiamonds, characterized by hybrid dipolar resonances of electrical (silver) and magnetic (diamond) nature. Hybrid metal-dielectric particles were prepared by means of nanosecond IR-laser ablation of solid silver target in diamond hydrosols with consecutive Ag-capping of diamonds, and were characterized by scanning electron microscopy, UV-vis, photoluminescence and energy-dispersive X-ray spectroscopy. Intensities of the SLFR-scattered components and their size-dependent spectral shifts were measured in the highly sensitive stimulated scattering regime, indicating the high (≈ 30%) SLFRS conversion efficiency and the resonant character of the scattering species.

  5. Improvement of the frequency-doubling efficiency of high-average-power lasers using multicrystal scheme with opposite thermal properties

    Directory of Open Access Journals (Sweden)

    Ying Chen

    Full Text Available Various multicrystal schemes have been widely used in the frequency conversion process of high power lasers or short-pulse lasers. Here we propose and numerically demonstrate a novel multicrystal scheme for improving the frequency-doubling efficiency of high-average-power lasers. Our proposed multicrystal scheme includes two different kinds of nonlinear crystals with opposite thermal properties, in which thermal-induced phase mismatches in the first crystal may be compensated by the next crystal. As a result, the sensitivity of conversion efficiency to temperature deviations is reduced. The simulation results show that the temperature acceptance bandwidth of our two-crystal scheme is 5 times larger than that of common single crystal scheme. And a broader temperature acceptance bandwidth will be obtained if a three-crystal scheme is adopted. More important of all, the temperature-insensitive property of multicrystal scheme is independent of pump wavelength, which means it can be applied in various high-average-power laser systems. OCIS codes: (190.2620 Harmonic generation and mixing, (190.4410 Nonlinear optics, (140.6810 Thermal effects

  6. Compact, single-frequency, doubly resonant optical parametric oscillator pumped in an achromatic phase-adapted double-pass geometry.

    Science.gov (United States)

    Hardy, B; Berrou, A; Guilbaud, S; Raybaut, M; Godard, A; Lefebvre, M

    2011-03-01

    We report on a nested-cavity, doubly resonant optical parametric oscillator (NesCOPO) architecture for widely tunable, mid-IR, single-frequency generation. By use of an achromatic phase-adapted double-pass pumping scheme, this new, low-threshold, semimonolithic architecture only requires two free-standing cavity mirrors and a nonlinear crystal with a mirror coating deposited on its input facet while the other facet is antireflection coated. It is thus as simple and compact as any basic linear optical parametric oscillator cavity, is easily tunable, and displays low sensitivity to mechanical vibrations. Using a high-repetition-rate (4.8 kHz) microlaser as the pump source of the NesCOPO, we demonstrate a compact source that provides pulsed, stable single-frequency output over a wide spectral range (3.8-4.3 μm) with a high peak power (up to 50 W), which are properties well suited for practical gas sensing applications.

  7. Tunable error-free optical frequency conversion of a 4ps optical short pulse over 25 nm by four-wave mixing in a polarisation-maintaining optical fibre

    Science.gov (United States)

    Morioka, T.; Kawanishi, S.; Saruwatari, M.

    1994-05-01

    Error-free, tunable optical frequency conversion of a transform-limited 4.0 ps optical pulse signalis demonstrated at 6.3 Gbit/s using four-wave mixing in a polarization-maintaining optical fibre. The process generates 4.0-4.6 ps pulses over a 25nm range with time-bandwidth products of 0.31-0.43 and conversion power penalties of less than 1.5 dB.

  8. Efficient coupling of 527 nm laser beam power to a long scale-length plasma

    International Nuclear Information System (INIS)

    Moody, J.D.; Divol, L.; Glenzer, S.H.; MacKinnon, A.J.; Froula, D.H.; Gregori, G.; Kruer, W.L.; Meezan, N.B.; Suter, L.J.; Williams, E.A.; Bahr, R.; Seka, W.

    2006-01-01

    We experimentally demonstrate that application of laser smoothing schemes including smoothing by spectral dispersion (SSD) and polarization smoothing (PS) increases the intensity range for efficient coupling of frequency doubled (527 nm) laser light to a long scale-length plasma with n e /n cr equals 0.14 and T e equals 2 keV. (authors)

  9. Low and high-frequency TENS in post-episiotomy pain relief: a randomized, double-blind clinical trial

    Science.gov (United States)

    Pitangui, Ana C. R.; Araújo, Rodrigo C.; Bezerra, Michelle J. S.; Ribeiro, Camila O.; Nakano, Ana M. S.

    2014-01-01

    Objective To evaluate the effectiveness of low-frequency TENS (LFT) and high-frequency TENS (HFT) in post-episiotomy pain relief. Method A randomized, controlled, double-blind clinical trial with placebo composed of 33 puerperae with post-episiotomy pain. TENS was applied for 30 minutes to groups: HFT(100 Hz; 100 µs), LFT (5 Hz; 100 µs), and placebo (PT). Four electrodes were placed in parallel near the episiotomy and four pain evaluations were performed with the numeric rating scale. The first and the second evaluation took place before TENS application and immediately after its removal and were done in the resting position and in the activities of sitting and ambulating. The third and fourth evaluation took place 30 and 60 minutes after TENS removal, only in the resting position. Intragroup differences were verified using the Friedman and Wilcoxon tests, and the intergroup analysis employed the Kruskal-Wallis test. Results In the intragroup analysis, there was no significant difference in the PT during rest, sitting, and ambulation (P>0.05). In the HFT and LFT, a significant difference was observed in all activities (P<0.001). In the intergroup analysis, there was a significant difference in the resting position in the HFT and LFT (P<0.001). In the sitting activity, a significant difference was verified in the second evaluation in the HFT and LFT (P<0.008). No significant difference was verified among the groups in ambulation (P<0.20). Conclusions LFT and HFT are an effective resource that may be included in the routine of maternity wards. PMID:24675915

  10. Low and high-frequency TENS in post-episiotomy pain relief: a randomized, double-blind clinical trial

    Directory of Open Access Journals (Sweden)

    Ana C. R. Pitangui

    2014-01-01

    Full Text Available Objective: To evaluate the effectiveness of low-frequency TENS (LFT and high-frequency TENS (HFT in post-episiotomy pain relief. Method: A randomized, controlled, double-blind clinical trial with placebo composed of 33 puerperae with post-episiotomy pain. TENS was applied for 30 minutes to groups: HFT(100 Hz; 100 µs, LFT (5 Hz; 100 µs, and placebo (PT. Four electrodes were placed in parallel near the episiotomy and four pain evaluations were performed with the numeric rating scale. The first and the second evaluation took place before TENS application and immediately after its removal and were done in the resting position and in the activities of sitting and ambulating. The third and fourth evaluation took place 30 and 60 minutes after TENS removal, only in the resting position. Intragroup differences were verified using the Friedman and Wilcoxon tests, and the intergroup analysis employed the Kruskal-Wallis test. Results: In the intragroup analysis, there was no significant difference in the PT during rest, sitting, and ambulation (P>0.05. In the HFT and LFT, a significant difference was observed in all activities (P<0.001. In the intergroup analysis, there was a significant difference in the resting position in the HFT and LFT (P<0.001. In the sitting activity, a significant difference was verified in the second evaluation in the HFT and LFT (P<0.008. No significant difference was verified among the groups in ambulation (P<0.20. Conclusions: LFT and HFT are an effective resource that may be included in the routine of maternity wards.

  11. Single-frequency operation of a broad-area laser diode by injection locking of a complex spatial mode via a double phase conjugate mirror

    NARCIS (Netherlands)

    van Voorst, P.D.; Offerhaus, Herman L.; Boller, Klaus J.

    2006-01-01

    We demonstrate what is believed to be the first phase-coherent locking of a high-power broad-area diode to a single-frequency master laser. We use photorefractive double phase conjugation to lock the diode in a selfoptimized complex spatial mode while the photorefractive crystal diffracts that

  12. Learning effect, normal range, and test-retest variability of Frequency Doubling Perimetry as a function of age, perimetric experience, and the presence or absence of glaucoma

    NARCIS (Netherlands)

    Heeg, GP; Ponsioen, TL; Jansonius, NM

    2003-01-01

    The learning effect for several different Frequency Doubling Perimetry parameters was studied in full threshold mode in a large group of patients (n = 342) of various ages, with and without perimetric experience, and with and without glaucoma. A significant learning effect was only found for the

  13. The Groningen Longitudinal Glaucoma Study. I. Baseline sensitivity and specificity of the frequency doubling perimeter and the GDx nerve fibre analyser

    NARCIS (Netherlands)

    Heeg, GP; Blanksma, LJ; Hardus, PLLJ; Jansonius, NM

    Purpose: To describe the baseline data of a large cohort of patients included for follow-up with perimetry using the frequency doubling technique (FDT) and with quantification of the retinal nerve fibre layer as assessed by GDx, and to calculate the sensitivity and specificity of both devices from

  14. Fine and hyperfine structure spectra of the ultra-violet 23S → 53P transition in 4He and 3He with a frequency doubled CW ring laser, detected via associative ionization

    International Nuclear Information System (INIS)

    Runge, S.; Pesnelle, A.; Perdrix, M.; Sevin, D.; Wolffer, N.; Watel, G.

    1982-01-01

    High resolution laser spectroscopy coupled to a sensitive method of detection via mass analysis of He + 2 ions produced in He(5 3 P) + He(1 1 S) collisions, is used to obtain the fine and hyperfine spectra of the ultra-violet He 2 3 S → 5 3 P transition. A cw tunable UV radiation around 294.5 nm is generated by intracavity frequency doubling a Rhodamine 6G single mode ring dye laser using an ADA crystal. Both spectra enable fine and hyperfine structures to be determined within a few MHz. The magnetic dipole coupling constant A of the 5 3 P term of 3 He is found to be -4326 +- 9 MHz (-0.1443 +- 0.0003 cm -1 ). (orig.)

  15. Cooperative Transmission in Mobile Wireless Sensor Networks with Multiple Carrier Frequency Offsets: A Double-Differential Approach

    Directory of Open Access Journals (Sweden)

    Kun Zhao

    2014-01-01

    Full Text Available As a result of the rapidly increasing mobility of sensor nodes, mobile wireless sensor networks (MWSNs would be subject to multiple carrier frequency offsets (MCFOs, which result in time-varying channels and drastically degrade the network performance. To enhance the performance of such MWSNs, we propose a relay selection (RS based double-differential (DD cooperative transmission scheme, termed RSDDCT, in which the best relay sensor node is selected to forward the source sensor node’s signals to the destination sensor node with the detect-and-forward (DetF protocol. Assuming a Rayleigh fading environment, first, exact closed-form expressions for the outage probability and average bit error rate (BER of the RSDDCT scheme are derived. Then, simple and informative asymptotic outage probability and average BER expressions at the large signal-to-noise ratio (SNR regime are presented, which reveal that the RSDDCT scheme can achieve full diversity. Furthermore, the optimum power allocation strategy in terms of minimizing the average BER is investigated, and simple analytical solutions are obtained. Simulation results demonstrate that the proposed RSDDCT scheme can achieve excellent performance over fading channels in the presence of unknown random MCFOs. It is also shown that the proposed optimum power allocation strategy offers substantial average BER performance improvement over the equal power allocation strategy.

  16. Expansion of lower-frequency locally resonant band gaps using a double-sided stubbed composite phononic crystals plate with composite stubs

    Energy Technology Data Exchange (ETDEWEB)

    Li, Suobin; Chen, Tianning [School of Mechanical Engineering and State Key Laboratory for Strength and Vibration of Mechanical Structures, Xi' an Jiaotong University, Xi' an, Shaanxi 710049 (China); Wang, Xiaopeng, E-mail: xpwang@mail.xjtu.edu.cn [School of Mechanical Engineering and State Key Laboratory for Strength and Vibration of Mechanical Structures, Xi' an Jiaotong University, Xi' an, Shaanxi 710049 (China); Li, Yinggang [Key Laboratory of High Performance Ship Technology of Ministry of Education, Wuhan University of Technology, Wuhan, 430070 (China); Chen, Weihua [School of Mechanical Engineering and State Key Laboratory for Strength and Vibration of Mechanical Structures, Xi' an Jiaotong University, Xi' an, Shaanxi 710049 (China)

    2016-06-03

    We studied the expansion of locally resonant complete band gaps in two-dimensional phononic crystals (PCs) using a double-sided stubbed composite PC plate with composite stubs. Results show that the introduction of the proposed structure gives rise to a significant expansion of the relative bandwidth by a factor of 1.5 and decreases the opening location of the first complete band gap by a factor of 3 compared to the classic double-sided stubbed PC plate with composite stubs. Furthermore, more band gaps appear in the lower-frequency range (0.006). These phenomena can be attributed to the strong coupling between the “analogous rigid mode” of the stub and the anti-symmetric Lamb modes of the plate. The “analogous rigid mode” of the stub is produced by strengthening the localized resonance effect of the composite plates through the double-sided stubs, and is further strengthened through the introduction of composite stubs. The “analogous rigid mode” of the stubs expands the out-of-plane band gap, which overlaps with in-plane band gap in the lower-frequency range. As a result, the complete band gap is expanded and more complete band gaps appear. - Highlights: • Expansion of lower-frequency locally resonant BGs using novel composite phononic crystals plates. • The proposed structure expands the relative bandwidth 1.5 times compared to classic doubled-sided stubbed PC plates. • The opening location of the first complete BG decreases 3 times compared to the classic doubled-sided stubbed PC plates. • The concept “analogous rigid mode” is put forward to explain the expansion of lower-frequency BGs.

  17. UV Generation of 25 mJ/pulse at 289 nm for Ozone Lidar

    Science.gov (United States)

    Storm, Mark E.; Marsh, Waverly; Barnes, James C.

    1998-01-01

    Our paper describes a technique for generating tunable UV laser radiation between 250-300 nm capable of energies up to 30-5O mJ/pulse. The tunability of this source is attractive for selecting ozone absorption cross sections which are optimal for ozone DIAL detection throughout the troposphere. A Nd:YAG laser is used to pump a pulsed titanium sapphire laser which is then frequency tripled into the UV. Titanium sapphire (TiS) lases robustly between 750-900 nm. In initial experiments we have converted 110 mJ of 867 nm from a TiS laser into 28 mJ at 289 nm. The energy conversion efficiency was 62% for doubling into 433 nm and 25% into 289 nm.

  18. The residual pattern of double thin-film over-etching for the fabrication of continuous patterns with dimensions varying from 50 nm to millimeters over a large area

    International Nuclear Information System (INIS)

    Chen, L Q; Chan-Park, Mary B; Yang Chun; Zhang Qing

    2008-01-01

    Attempts at heavy edge over-etching of a single thin film under a photoresist to leave behind a residual smaller patterned line as a mask for nanostructure fabrication frequently fail due to detachment of the photoresist above it. We have accordingly developed a technique named 'residual pattern of double thin-film over-etching' (RDTO) to obtain a nanoscale residual pattern of the bottom thin film after extensive edge over-etching. When Au and Cr were used as the top and bottom thin films, respectively, heavy over-etching of Cr for use as a mask for nanopatterning of the underlying silicon substrate was feasible. Three patterns were fabricated for demonstration of the RDTO technique, and nanopatterns with linewidths as small as 50 nm were obtained. More importantly, our technique allows the fabrication of a single pattern with feature dimensions that vary continuously from a few tens of nanometers to a few millimeters at different positions. In addition, we have developed simple models to analyze the hydrodynamic and surface tension effects during the over-etching procedure to show the feasibility of RDTO. This technique will find diverse applications in micro- and nano-fluidics, lab-on-a-chip nano-arrays and biomedical engineering

  19. Low-Frequency Fatigue Assessed as Double to Single Twitch Ratio after Two Bouts of Eccentric Exercise of the Elbow Flexors.

    Science.gov (United States)

    Janecki, Damian; Jaskólska, Anna; Marusiak, Jarosław; Jaskólski, Artur

    2016-12-01

    The aim of this study was to assess low-frequency fatigue as a double to single twitch ratio after repeated eccentric exercise of the elbow flexors. Maximal isometric torque, single and double twitch responses and low-frequency fatigue were assessed on the elbow flexors in 16 untrained male volunteers before, immediately after, 24 and 48 hours following two bouts of eccentric exercise consisted of 30 repetitions of lowering a dumbbell adjusted to ~75% of each individual's maximal isometric torque. Maximal isometric torque and electrically evoked responses decreased significantly in all measurements after the first bout of eccentric exercise (p twitch ratio could be used as a sensitive tool in the evaluation of muscle recovery and adaptation to repeated eccentric exercise.

  20. Probing the internal energy structure of a serially coupled double quantum dot system with Rashba spin-orbit coupling through finite-frequency shot noise

    Science.gov (United States)

    Xue, Hai-Bin; Liu, Xu-Ping; Chen, Bin

    2018-01-01

    The finite-frequency shot noise of electron transport through a serially coupled double quantum dot system with Rashba spin-orbit coupling is studied based on an effective particle-number-resolved quantum master equation. We demonstrate that the finite-frequency shot noise displays an obvious dip, and the dip position, which is independent of the spin polarizations of the source and drain electrodes, is determined by the energy difference between the coherent singly-occupied eigenstates of the quantum dot system. These results suggest that the dip position of the finite-frequency shot noise can be used to quantitatively extract the information about the energy difference between the coherent singly-occupied eigenstates and the magnitude of Rashba spin-orbit coupling. The predicted properties of the finite-frequency shot noise are of particular interest for understanding of the internal dynamics of the coupled quantum dot systems.

  1. The frequency of double-positive thymocytes expressing an αβ TCR clonotype regulates peripheral CD4 T cell compartment homeostasis

    Science.gov (United States)

    Reed, Amy J; Zarrabi, Yasaman; Perate, Alison L; Jeganathan, Arjun; Naji, Ali; Noorchashm, Hooman

    2005-01-01

    The present study aimed to determine whether the frequency of double positive (DP) thymocytes expressing αβ T-cell receptor (TCR) clonotypes at the time of selection regulates peripheral CD4 T-cell compartment size. Scid recipients were inoculated with various ratios of TCR Cα0/0 and wild-type bone marrow (BM) stem cells. Increasing the frequency of TCR Cα0/0 thymocytes at steady-state introduced a graded decrease in the maturation probability of the total DP thymocyte pool. At 12–14 weeks following BM inoculation, the frequency of TCR Cα0/0 DP thymocytes was inversely correlated with that of CD4 single positive (SP) thymocytes. Notwithstanding, a decreased frequency of wild-type DP thymocytes led to a marked increase in their transit efficiency from the DP to SP compartments. The frequency-dependent increase in thymocyte transit efficiency was associated with a CD4 SP cell surface phenotype indicative of increased antigenic experience. Importantly, the frequency of DP thymocytes capable of expressing TCR clonotypes dictated the steady-state size of the peripheral CD4 T cell compartment and its potential for homeostatic proliferation. Collectively, these results indicate that the efficiency of DP to CD4 SP transit is a frequency dependent process, which determines (1) the steady-state size of the peripheral T cell compartment and (2) the threshold for homeostatic expansion of peripheral CD4 T cells. PMID:16236130

  2. Implementation of wireless battery-free microgyrosensor by utilizing one-port SAW delay line and an antenna with double resonant frequencies

    Science.gov (United States)

    Fu, C.; Elmarzia, O.; Lee, K.

    2014-03-01

    A wireless, battery-free gyroscope was developed by employing a one-port surface acoustic wave (SAW) reflective delay line, a SAW resonator, and an antenna. Two SAW devices with different center frequencies were simultaneously activated by one antenna with double resonant frequencies. During wireless testing, the developed gyroscope showed clear reflection peaks with high S/N ratios in both the time and frequency domains. Upon rotation of the device, large shifts of the reflection peaks were observed owing to a secondary wave interference effect caused by the Coriolis force that depends on the spinning rate. The measured sensitivity and linearity of the developed gyroscope were, respectively, 1.35 deg/(deg/s) and 0.91, which are promising values for our targeted applications. The temperature and vibration/shock effects were also characterized

  3. Effect of asymmetrical double-pockets and gate-drain underlap on Schottky barrier tunneling FET: Ambipolar conduction vs. high frequency performance

    Science.gov (United States)

    Shaker, Ahmed; Ossaimee, Mahmoud; Zekry, A.

    2016-08-01

    In this paper, a proposed structure based on asymmetrical double pockets SB-TFET with gate-drain underlap is presented. 2D extensive modeling and simulation, using Silvaco TCAD, were carried out to study the effect of both underlap length and pockets' doping on the transistor performance. It was found that the underlap from the drain side suppresses the ambipolar conduction and doesn't enhance the high-frequency characteristics. The enhancement of the high-frequency characteristics could be realized by increasing the doping of the drain pocket over the doping of the source pocket. An optimum choice was found which gives the conditions of minimum ambipolar conduction, maximum ON current and maximum cut-off frequency. These enhancements render the device more competitive as a nanometer transistor.

  4. The intermediate frequency modes of single- and double-walled carbon nanotubes: a Raman spectroscopic and in situ Raman spectroelectrochemical study.

    Science.gov (United States)

    Kalbac, Martin; Kavan, Ladislav; Zukalová, Markéta; Dunsch, Lothar

    2006-05-24

    The intermediate frequency modes (IFM) of single-walled carbon nanotubes (SWCNTs) and double-walled carbon nanotubes (DWCNTs) were analyzed by Raman spectroscopy and in situ Raman spectroelectrochemistry. The inner and outer tubes of DWCNTs manifested themselves as distinct bands in the IFM region. This confirmed the diameter dependence of IFM frequencies. Furthermore, the analysis of inner tubes of DWCNTs allowed a more-precise assignment of the bands in the IFM region to features intrinsic for carbon nanotubes. Although the inner tubes in DWCNTs are assumed to be structurally perfect, the role of defects on IFM was discussed. The dependence of IFM on electrochemical charging was also studied. In situ spectroelectrochemical data provide a means to distinguish the bands of the outer and inner tubes.

  5. Research on spectrum broadening covering visible light of a fiber femtosecond optical frequency comb for absolute frequency measurement

    Science.gov (United States)

    Xing, Shuai; Wu, Tengfei; Li, Shuyi; Xia, Chuanqing; Han, Jibo; Zhang, Lei; Zhao, Chunbo

    2018-03-01

    As a bridge connecting microwave frequency and optical frequency, femtosecond laser has important significance in optical frequency measurement. Compared with the traditional Ti-sapphire femtosecond optical frequency comb, with the advantages of compact structure, strong anti-interference ability and low cost, the fiber femtosecond optical frequency comb has a wider application prospect. An experiment of spectrum broadening in a highly nonlinear photonic crystal fiber pumped by an Er-fiber mode-locked femtosecond laser is studied in this paper. Based on optical amplification and frequency doubling, the central wavelength of the output spectrum is 780nm and the average power is 232mW. With the femtosecond pulses coupled into two different photonic crystal fibers, the coverage of visible spectrum is up to 500nm-960nm. The spectral shape and width can be optimized by changing the polarization state for satisfying the requirments of different optical frequencies measurement.

  6. Clearance of yellow tattoo ink with a novel 532-nm picosecond laser.

    Science.gov (United States)

    Alabdulrazzaq, Hamad; Brauer, Jeremy A; Bae, Yoon-Soo; Geronemus, Roy G

    2015-04-01

    Although technology and tattoo removal methods continue to evolve, yellow pigment clearance continues to be challenging and usually unsuccessful. We describe a case series of six tattoos containing yellow ink, successfully treated with a frequency-doubled Nd:YAG 532-nm picosecond laser. Case series with six subjects participating for the treatment of multicolored tattoos that contain yellow pigment. Treatments performed with a frequency-doubled Nd:YAG 532-nm picosecond laser at 6-8 week intervals. One subject achieved complete clearance of the treated site after one session, and five subjects required 2-4 treatments to achieve over 75% clearance. Minimal downtime was experienced, and no scarring or textural skin changes were observed in any of the treated sites. This is the first case series that demonstrates effective and consistent reduction of yellow tattoo ink using a frequency doubled Nd:YAG 532-nm laser with a picosecond pulse duration. Treatments were well tolerated and subjects had positive outcomes. This is a small observational case series from an ongoing clinical trial, and studies with a larger sample size and comparative group are needed in the future. © 2015 Wiley Periodicals, Inc.

  7. Detection of coherent waves by time-frequency coherency with a downhole double 3 component detector; Koseinai 3 jiku AE double zonde system no kaihatsu to jikan (shuhasu hyogen ni yoru coherent ha no kenshutsu)

    Energy Technology Data Exchange (ETDEWEB)

    Takayama, J.; Asanuma, H.; Lesniak, A.; Niitsuma, H. [Tohoku University, Sendai (Japan). Faculty of Engineering

    1997-05-27

    A downhole double three component detector system was developed to detect coherent waves in subsurface elastic waves by using the time-frequency-coherency (TFC) method. The TFC method measures elastic waves on two points which are several ten centimeters to several meters apart, and estimates arrival time of a coherent wave and its frequency characteristics, by expressing coherence of waveforms in terms of time and frequency with regard to the two waveforms measured between the two points. If the system is to be applied to downhole elastic wave measurement, it is preferable to detect a three-dimensional particle movement locus of the elastic waves to extract information at the maximum extent. Two sondes (each sonde consists of three components and contains an azimuth detector) are coupled (the jointing distance is variable) and installed in a well. The obtained six-component signal goes through FM modulation and mixing by a modulator in the sonde, is integrated into one component, and transmitted to the ground surface. The system was found capable of detecting the three-dimensional particle movement. However, this performance is inferior to conventional single sondes, hence requiring improvement. It was discovered possible to detect coherent waves by applying the TFC method to the Kakkonda field data. 4 refs., 9 figs.

  8. Sum frequency generation vibrational spectroscopy of 1,3-butadiene hydrogenation on 4 nm Pt@SiO2, Pd@SiO2, and Rh@SiO2 core-shell catalysts.

    Science.gov (United States)

    Krier, James M; Michalak, William D; Cai, Xiaojun; Carl, Lindsay; Komvopoulos, Kyriakos; Somorjai, Gabor A

    2015-01-14

    1,3-Butadiene (1,3-BD) hydrogenation was performed on 4 nm Pt, Pd, and Rh nanoparticles (NPs) encapsulated in SiO2 shells at 20, 60, and 100 °C. The core-shells were grown around polyvinylpyrrolidone (PVP) coated NPs (Stöber encapsulation) prepared by colloidal synthesis. Sum frequency generation (SFG) vibrational spectroscopy was performed to correlate surface intermediates observed in situ with reaction selectivity. It is shown that calcination is effective in removing PVP, and the SFG signal can be generated from the metal surface. Using SFG, it is possible to compare the surface vibrational spectrum of Pt@SiO2 (1,3-BD is hydrogenated through multiple paths and produces butane, 1-butene, and cis/trans-2-butene) to Pd@SiO2 (1,3-BD favors one path and produces 1-butene and cis/trans-2-butene). In contrast to Pt@SiO2 and Pd@SiO2, SFG and kinetic experiments of Rh@SiO2 show a permanent accumulation of organic material.

  9. Sum Frequency Generation Vibrational Spectroscopy of 1,3-Butadiene Hydrogenation on 4 nm Pt@SiO 2 , Pd@SiO 2 , and Rh@SiO 2 Core–Shell Catalysts

    KAUST Repository

    Krier, James M.

    2015-01-14

    © 2014 American Chemical Society. 1,3-Butadiene (1,3-BD) hydrogenation was performed on 4 nm Pt, Pd, and Rh nanoparticles (NPs) encapsulated in SiO2 shells at 20, 60, and 100 °C. The core-shells were grown around polyvinylpyrrolidone (PVP) coated NPs (Stöber encapsulation) prepared by colloidal synthesis. Sum frequency generation (SFG) vibrational spectroscopy was performed to correlate surface intermediates observed in situ with reaction selectivity. It is shown that calcination is effective in removing PVP, and the SFG signal can be generated from the metal surface. Using SFG, it is possible to compare the surface vibrational spectrum of Pt@SiO2 (1,3-BD is hydrogenated through multiple paths and produces butane, 1-butene, and cis/trans-2-butene) to Pd@SiO2 (1,3-BD favors one path and produces 1-butene and cis/trans-2-butene). In contrast to Pt@SiO2 and Pd@SiO2, SFG and kinetic experiments of Rh@SiO2 show a permanent accumulation of organic material.

  10. Thin disk amplifier-based 40 mJ, 1 kHz, picosecond laser at 515 nm.

    Science.gov (United States)

    Novák, Jakub; Green, Jonathan T; Metzger, Thomas; Mazanec, Tomáš; Himmel, Bedřich; Horáček, Martin; Hubka, Zbyněk; Boge, Robert; Antipenkov, Roman; Batysta, František; Naylon, Jack A; Bakule, Pavel; Rus, Bedřich

    2016-03-21

    We report on a frequency-doubled picosecond Yb:YAG thin disk regenerative amplifier, developed as a pump laser for a kilohertz repetition rate OPCPA. At a repetition rate of 1 kHz, the compressed output of the regenerative amplifier has a pulse duration of 1.2 ps and pulse energy of 90 mJ with energy stability of σ 2 < 1.2. The pulses are frequency doubled in an LBO crystal yielding 42 mJ at 515 nm.

  11. Second-order fractional Talbot effect induced frequency-doubling optical pulse injection for 40 GHz rational-harmonic mode-locking of an SOA fiber laser

    Science.gov (United States)

    Kang, Jung-Jui; Lin, Yung-Hsiang; Lee, Chao-Kuei; Lin, Gong-Ru

    2013-09-01

    A second-order fractional Talbot effect induced frequency-doubling of a 10 GHz optical pulse-train is demonstrated to backward injection mode-lock a semiconductor optical amplifier fiber laser (SOAFL) for 40 GHz rational-harmonic mode-locking (RHML). That is, a real all-optical gain-modulation of the SOAFL can be created by injecting such a time-multiplexed but pseudo-frequency-doubled pulse-train into the cavity. The time-multiplexing pulse-train can thus be transformed into a frequency-multiplied pulse-train via cross-gain modulation (XGM). The optical pulse-train at 10 GHz is generated by nonlinearly driving an electro-absorption modulator (EAM), which experiences the second-order fractional Talbot effect after propagating through a 4 km long dispersion compensation fiber (DCF). The DCF not only plays the role of frequency-doubler but also compensates the frequency chirp of the 10 GHz optical pulse-train. The pulsewidth broadening from 22 to 60 ps for initiating the time-domain Talbot effect is simulated by the nonlinear Schrödinger equation. With careful detuning of the RF modulation power of the EAM at 5 dBm, the generated 20 GHz optical pulse-train exhibits a positive frequency chirp with minimum peak-to-peak value of 2 GHz, and the peak-amplitude fluctuation between adjacent pulses is below 1.4%. In comparison with the SOAFL pulse-train repeated at 40 GHz generated by the fourth-order purely RHML process, the optimized second-order fractional Talbot effect in combination with the second-order RHML mechanism significantly enhances the modulation-depth of RHML, thus improving the on/off extinction ratio of the 40 GHz SOAFL pulse-train from 1.8 to 5.6 dB. Such a new scheme also provides a more stable 40 GHz RHML pulse-train from the SOAFL with its timing jitter reducing from 0.51 to 0.23 ps.

  12. Effect of the probiotic strain Bifidobacterium animalis subsp. lactis, BB-12®, on defecation frequency in healthy subjects with low defecation frequency and abdominal discomfort: a randomised, double-blind, placebo-controlled, parallel-group trial.

    Science.gov (United States)

    Eskesen, Dorte; Jespersen, Lillian; Michelsen, Birgit; Whorwell, Peter J; Müller-Lissner, Stefan; Morberg, Cathrine M

    2015-11-28

    The aim of the present study was to investigate the effect of Bifidobacterium animalis subsp. lactis, BB-12®, on two primary end points - defecation frequency and gastrointestinal (GI) well-being - in healthy adults with low defecation frequency and abdominal discomfort. A total of 1248 subjects were included in a randomised, double-blind, placebo-controlled trial. After a 2-week run-in period, subjects were randomised to 1 or 10 billion colony-forming units/d of the probiotic strain BB-12® or a matching placebo capsule once daily for 4 weeks. Subjects completed a diary on bowel habits, relief of abdominal discomfort and symptoms. GI well-being, defined as global relief of abdominal discomfort, did not show significant differences. The OR for having a defecation frequency above baseline for ≥50% of the time was 1·31 (95% CI 0·98, 1·75), P=0·071, for probiotic treatment overall. Tightening the criteria for being a responder to an increase of ≥1 d/week for ≥50 % of the time resulted in an OR of 1·55 (95% CI 1·22, 1·96), P=0·0003, for treatment overall. A treatment effect on average defecation frequency was found (P=0·0065), with the frequency being significantly higher compared with placebo at all weeks for probiotic treatment overall (all Pprobiotic strain BB-12® resulted in a clinically relevant benefit on defecation frequency. The results suggest that consumption of BB-12® improves the GI health of individuals whose symptoms are not sufficiently severe to consult a doctor (ISRCTN18128385).

  13. High-energy long duration frequency-doubled Nd:YAG laser and application to venous occlusion

    Science.gov (United States)

    Zhang, Laiming; Yang, Guilong; Li, Dianjun; Lu, Qipeng; Gu, Huadong; Zhu, Linlin; Zhao, Zhenwu; Li, Xin; Tang, Yuguo; Guo, Jin

    2005-01-01

    Laser treatment represents an attractive option to other methods of vessel diseases especially varicose veins. A long pulse (30~50ms) 532nm laser (Fig.1) is used in our experiments with the pulse duration matching the thermal relaxation time of the vessels and the green laser matching the absorption spectrum peak of the blood. Laser irradiates nude vein vessels directly or exterior skin to finish operation faster and to acquire the practical data for upper enteron varicose vein treatment in several animal experiments performed in vivo. The 5J-energy pulse allows us to finely occlude rabbit or dog"s vein vessels up to 2 mm in diameter when irradiating them off external skin (Fig.2). Blood vessels are occluded at once and later biopsy specimens show the immediate and long-term lasting occlusion effect. While irradiating vessels directly (Fig.3), the vessels are usually irradiated to perforate, detailed causes are still under investigation. Animal experiments show long pulse green laser therapy is a safe and effective solution to the vein"s occlusion, which promises such laser with high energy of each pulse and 30~50 ms duration is an ideal candidate for vessel diseases treatment.

  14. Detection of target distance in the presence of an interfering reflection using a frequency-stepped double side-band suppressed carrier microwave radar system

    Science.gov (United States)

    Ybarra, Gary A.; Ardalan, Sasan H.; Hearn, Chase P.; Neece, Robert T.; Marshall, Robert E.

    1991-01-01

    A technique for detecting the distance to a highly reflective target in the presence of an interesting reflection using a frequency-stepped double-sideband suppressed carrier (DSBSC) microwave-millimeter-wave radar system is analytically derived. The main result of the analysis shows that the measured group delays produced by the DSBSC system possess a periodicity inversely proportional to the difference between the time delays to the target and interferer, independent of the signal-to-interference ratio (SIR). Simulation results are presented in the context of electron plasma density range estimation using a block diagram communications CAD tool. A unique and accurate plasma model is introduced. A high-resolution spectral estimation technique based on an autoregressive time series analysis is applied to the measured group delays, and it is shown that accurate target distance estimates may be obtained, independent of SIR.

  15. Comparison of visual field test results obtained through Humphrey matrix frequency doubling technology perimetry versus standard automated perimetry in healthy children

    Directory of Open Access Journals (Sweden)

    Sibel Kocabeyoglu

    2013-01-01

    Full Text Available Aims : The aim of this study was to compare the visual field test results in healthy children obtained via the Humphrey matrix 24-2 threshold program and standard automated perimetry (SAP using the Swedish interactive threshold algorithm (SITA-Standard 24-2 test. Materials and Methods: This prospective study included 55 healthy children without ocular or systemic disorders who underwent both SAP and frequency doubling technology (FDT perimetry visual field testing. Visual field test reliability indices, test duration, global indices (mean deviation [MD], and pattern standard deviation [PSD] were compared between the 2 tests using the Wilcoxon signed-rank test and paired t-test. The performance of the Humphrey field analyzer (HFA 24-2 SITA-standard and frequency-doubling technology Matrix 24-2 tests between genders were compared with Mann-Whitney U-test. Results: Fifty-five healthy children with a mean age of 12.2 ± 1.9 years (range from 8 years to 16 years were included in this prospective study. The test durations of SAP and FDT were similar (5.2 ± 0.5 and 5.1 ± 0.2 min, respectively, P = 0.651. MD and the PSD values obtained via FDT Matrix were significantly higher than those obtained via SAP (P < 0.001, and fixation losses and false negative errors were significantly less with SAP (P < 0.05. A weak positive correlation between the two tests in terms of MD (r = 0.352, P = 0.008 and PSD (r = 0.329, P = 0.014 was observed. Conclusion: Children were able to complete both the visual test algorithms successfully within 6 min. However, SAP testing appears to be associated with less depression of the visual field indices of healthy children. FDT Matrix and SAP should not be used interchangeably in the follow-up of children.

  16. Effect of platelet-rich fibrin on frequency of alveolar osteitis following mandibular third molar surgery: a double-blinded randomized clinical trial.

    Science.gov (United States)

    Eshghpour, Majid; Dastmalchi, Parisa; Nekooei, Amir Hossein; Nejat, AmirHossein

    2014-08-01

    To evaluate the effectiveness of platelet-rich fibrin (PRF) in preventing the development of alveolar osteitis (AO). In a double-blinded study, patients with bilateral impacted mandibular third molars underwent surgical extractions, with one socket receiving PRF and the other one serving as a control. The surgeon and patient were unaware of the study or control side. The predictor variable was the PRF application and was categorized as PRF and non-PRF. The outcome variable was the development of AO during the first postoperative week. Other study variables included age, gender, smoking status, irrigation volume, extraction difficulty, surgeon experience, and number of anesthetic cartridges. Data were analyzed using χ(2) and t tests, with the significance level set at a P value less than .05. Seventy-eight patients (mean age, 25 yr) underwent 156 impacted third molar surgeries. The overall frequency of AO was 14.74% for all surgeries. The frequency of AO in the PRF group was significantly lower than in the non-PRF group (odds ratio = 0.44; P third molar surgery. Copyright © 2014 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

  17. Optimization of Vertical Double-Diffused Metal-Oxide Semiconductor (VDMOS) Power Transistor Structure for Use in High Frequencies and Medical Devices.

    Science.gov (United States)

    Farhadi, Rozita; Farhadi, Bita

    2014-01-01

    Power transistors, such as the vertical, double-diffused, metal-oxide semiconductor (VDMOS), are used extensively in the amplifier circuits of medical devices. The aim of this research was to construct a VDMOS power transistor with an optimized structure to enhance the operation of medical devices. First, boron was implanted in silicon by implanting unclamped inductive switching (UIS) and a Faraday shield. The Faraday shield was implanted in order to replace the gate-field parasitic capacitor on the entry part of the device. Also, implanting the UIS was used in order to decrease the effect of parasitic bipolar junction transistor (BJT) of the VDMOS power transistor. The research tool used in this study was Silvaco software. By decreasing the transistor entry resistance in the optimized VDMOS structure, power losses and noise at the entry of the transistor were decreased, and, by increasing the breakdown voltage, the lifetime of the VDMOS transistor lifetime was increased, which resulted in increasing drain flow and decreasing Ron. This consequently resulted in enhancing the operation of high-frequency medical devices that use transistors, such as Radio Frequency (RF) and electrocardiograph machines.

  18. Amplification at λ ∼ 2.8 A on Xe(L),(2s-bar2p-bar) double-vacancy states produced by 248 nm excitation of Xe clusters in plasma channels

    International Nuclear Information System (INIS)

    Borisov, Alex B; Song Xiangyang; Zhang Ping; Dasgupta, Arati; Davis, Jack; Kepple, Paul C; Dai Yang; Boyer, Keith; Rhodes, Charles K

    2005-01-01

    Xe(L),(2s-bar2p-bar) double-vacancy states undergo strong amplification in relativistic self-trapped plasma channels on 3d → 2p transitions in the λ = 2.78-2.81 A region. The 2 P 3/2 → 2 S 1/2 component at λ ≅ 2.786 A exhibits saturated amplification demonstrated by both (1) the observation of spectral hole-burning in the spontaneous emission profile and (2) the correlated enhancement of 3p → 2s cascade transitions ( 2 S 1/2 → 2 P j ; j = 1/2, 3/2) at λ = 2.558 and λ = 2.600 A. The condition of saturation places a lower limit of ∼10 17 W cm -2 on the intensity of the x-ray beam produced by the amplification in the channel. The anomalous strength of the amplification signalled by the saturation mirrors the equivalently anomalous behaviour observed for all 3d → 2p transitions corresponding to 2p-bar) single-vacancy Xe q+ arrays (q = 31, 32, 34, 35, 36) that exhibit gain. The conspicuous absence of amplification involving states with (2p-bar) 2 double-vacancy configurations suggests the operation of a selective interaction that enhances the production of 2s-bar2p-bar states. Overall, the generation of double-vacancy states of this genre demonstrates that an excitation rate approaching ∼1 W/atom for ionic species is achievable in self-trapped plasma channels

  19. Stable single-frequency output at 2.01 microm from a diode-pumped monolithic double diffusion-bonded Tm:YAG nonplanar ring oscillator at room temperature.

    Science.gov (United States)

    Gao, Chunqing; Gao, Mingwei; Zhang, Yunshan; Lin, Zhifeng; Zhu, Lingni

    2009-10-01

    We demonstrate a monolithic double diffusion-bonded monolithic Tm:YAG nonplanar ring laser pumped by a fiber-coupled laser diode. Up to 867 mW single-frequency output at 2.01 microm was obtained from the Tm:YAG system at room temperature, with a slope efficiency and an optical-optical efficiency of 31.6% and 19.2%. The power stability of the single frequency laser was 0.32% within 30 min.

  20. Double-Stranded Linear Duck Hepatitis B Virus (DHBV) Stably Integrates at a Higher Frequency than Wild-Type DHBV in LMH Chicken Hepatoma Cells

    Science.gov (United States)

    Gong, Shih S.; Jensen, Anne D.; Chang, C. J.; Rogler, Charles E.

    1999-01-01

    Integration of hepadnavirus DNAs into host chromosomes can have oncogenic consequences. Analysis of host-viral DNA junctions of DHBV identified the terminally duplicated r region of the viral genome as a hotspot for integration. Since the r region is present on the 5′ and 3′ ends of double-stranded linear (DSL) hepadnavirus DNAs, these molecules have been implicated as integration precursors. We have produced a LMH chicken hepatoma cell line (LMH 66-1 DSL) which replicates exclusively DSL duck hepatitis B virus (DHBV) DNA. To test whether linear DHBV DNAs integrate more frequently than the wild type open circular DHBV DNAs, we have characterized the integration frequency in LMH 66-1 DSL cells by using a subcloning approach. This approach revealed that 83% of the LMH 66-1 DSL subclones contained new integrations, compared to only 16% of subclones from LMH-D2 cells replicating wild-type open circular DHBV DNA. Also, a higher percentage of the LMH 66-1 DSL subclones contained two or more new integrations. Mathematical analysis suggests that the DSL DHBV DNAs integrated stably once every three generations during subcloning whereas wild-type DHBV integrated only once every four to five generations. Cloning and sequencing of new integrations confirmed the r region as a preferred integration site for linear DHBV DNA molecules. One DHBV integrant was associated with a small deletion of chromosomal DNA, and another DHBV integrant occurred in a telomeric repeat sequence. PMID:9882355

  1. High-speed singulation of electronic packages using a frequency-doubled Nd:YAG laser in a water jet and realization of a 200-W green laser

    Science.gov (United States)

    Wagner, Frank R.; Hu, Wentao; Spiegel, Akos; Vago, Nandor; Richerzhagen, Bernold

    2003-07-01

    Each electronic chip is packaged in order to connect the integrated circuit and the printed circuit board. In consequence high-speed singulation of packages is an important step in the manufacturing process of electronic devices. The widely used technique of abrasive sawing encounters problems due to the combination of different materials used in packages such as copper and mold compound. The sawing blade rapidly blunts because of the copper adhering to the saw blade and covering the diamonds. In fact, the abrasive saw, well adapted to silicon wafer sawing, has problems to adapt to package materials. It has already been shown that the water jet guided laser can be used for efficient high quality singulation of leadframe based packages. In this technique a low-pressure water jet guides the laser beam like an optical fiber, providing efficient cooling of the cutting kerf at exactly the point that was heated during the laser pulse. We present new cutting results using a frequency doubled Nd:YAG laser with 100 W average power, and the combination setup for generating a 200 W green laser beam. The timing between the two lasers can be precisely controlled.

  2. Generation of 99-mW continuous-wave 285-nm radiation for magneto-optical trapping of Mg atoms

    DEFF Research Database (Denmark)

    Madsen, Dorte Nørgaard; Yu, Ping; Balslev, Søren

    2002-01-01

    We have developed a tunable intense narrow-band 285 nm light source based on frequency doubling of 570 nm light in BBO. At input powers of 840 mW (including 130 mW used for locking purposes) we generate 99 mW UV radiation with an intensity profile suitable for laser-cooling experiments. The light...... is used for laser cooling of neutral magnesium atoms in a magneto-optical trap (MOT). We capture about 5 x 10(6) atoms directly from a thermal beam and find that the major loss mechanism of the magnesium MOT is a near-resonant two-photon ionization process....

  3. Frequency comb generation using femtosecond pulses and cross-phase modulation in optical fiber at arbitrary center frequencies.

    Science.gov (United States)

    Jones, D J; Diddams, S A; Taubman, M S; Cundiff, S T; Ma, L S; Hall, J L

    2000-03-01

    A technique is presented for generating optical frequency combs centered at arbitrary wavelengths by use of cross-phase modulation (XPM) between a femtosecond pulse train and a cw laser beam by copropagating these signals through an optical fiber. We report results from use of this method to place a 90-MHz frequency comb on an iodine-stabilized Nd:YAG laser at 1064 nm and on a frequency-doubled Nd:YVO(4) laser at 532 nm. XPM is verified to be the comb-generating process, and the width of the frequency comb is measured and compared with theory. The spacing of the frequency comb is compared with the femtosecond source, and a frequency measurement with this comb is demonstrated.

  4. Measure Of Frequency Of Alveolar Osteitis Using Two Different Methods Of Osteotomy In Mandibular Third Molar Impactions: A Double-Blind Randomized Clinical Trial.

    Science.gov (United States)

    Rashid, Hina; Hussain, Azmina; Sheikh, Abdul Hafeez; Azam, Kehkishan; Malik, Sofia; Amin, Muhammad

    2018-01-01

    Dento-alveolar surgical procedures involving third molar teeth are the most common surgical procedure in the field of surgery. The objective of this research was to analyse the impact of surgery on the incidence of alveolar osteitis after surgical removal of mandibular third molar and to compare two different bone cutting methods following impacted mandibular third molar surgery.. This double blinded randomized clinical trial was executed at the OPD of Department of Oral and Maxillofacial Surgery, Dow University of Health Sciences, Karachi. The study duration was four months. It was conducted on 60 patients needing unilateral mandibular third molar impaction removal. Patients were randomized to two groups (i.e., physio dispenser group and slow speed handpiece group) before surgery. The surgical procedure was performed under local anaesthesia by using standardized cross infection protocol. The frequency of alveolar osteitis was evaluated on thirdday postoperatively. Alveolar osteitis was diagnosed and confirmed by patient's history and clinical evaluation. Post-operative sequelae were observed and recorded objectively. Out of 60 patients', five patients experienced alveolar osteitis, and the incidence rate was 8.3%. A significant pvalue of 0.000 was calculated using binomial test for comparison of alveolar osteitis among both groups. Inter-examiner reliability was assessed by kappa and good (62%) agreement, which was found among the examiners, who diagnosed alveolar osteitis clinically. Post-operative sequelae were insignificant in slow speed hand piece group. It was observed that alveolar osteitis was reported in physio-dispenser group; similarly, post-operative complications were also more in this group as compared with slow speed-hand piece group. No surgical complications were observed in slow speed-hand piece group suggesting slow speed hand piece mode of osteotomy to be safer for third molar extraction as compared with physio-dispenser.

  5. Simultaneous wind and temperature measurements in lower atmosphere by a 3-frequency Doppler lidar with a Na double-edge magneto-optic filter

    Science.gov (United States)

    Huang, W.; Chu, X.; Wang, Z.; Roberts, B.; Yuan, T.; Yue, J.; Harrell, S.; She, C.

    2009-12-01

    We have developed a new lidar technology to simultaneously profile wind and temperature from the lower to the middle atmosphere. This was to use a Na double-edge magneto-optic filter (Na-DEMOF) in the receiver of a 3-frequency Na Doppler lidar to analyze the Doppler shift and width of the Rayleigh/Mie scattering returns from 5 to 50 km altitude range. In last AGU meeting we reported our first field demonstration of this technology with the Colorado State University’s Na lidar running at 0.4 W power and 75 cm diameter telescope. Reliable winds and temperatures were measured in the altitude range of 10-45 km at 1 km and 60 min resolutions. Further tests reveal strong wavy structures in our short-time data set. In order to assess the capability of this technique in resolving the gravity waves and to understand the origin of the wavy structures, two PMTs were integrated to improve the temporal resolution and field tests were conducted covering an entire night. The preliminary data retrieval reveals the calibration regarding the different responses of the two PMTs being a critical issue for this new technique. A second-generation Na-DEMOF has been designed for reliable and stable performance. It is currently under construction and will soon be tested in the field. In this paper we will present these field test results and assess the usefulness of this new technology in the study of atmospheric thermal and dynamic structures, especially gravity wave properties.

  6. On-chip measurements of Brownian relaxation of magnetic beads with diameters from 10 nm to 250 nm

    DEFF Research Database (Denmark)

    Østerberg, Frederik Westergaard; Rizzi, Giovanni; Hansen, Mikkel Fougt

    2013-01-01

    We demonstrate the use of planar Hall effect magnetoresistive sensors for AC susceptibility measurements of magnetic beads with frequencies ranging from DC to 1 MHz. This wide frequency range allows for measuring Brownian relaxation of magnetic beads with diameters ranging from 10 nm to 250 nm...

  7. Continuous-wave violet generation at 373.5 nm by frequency-doubled power-scaled near-infrared emitting Pr:YAlO.sub.3./sub. laser

    Czech Academy of Sciences Publication Activity Database

    Fibrich, Martin; Jelínková, H.

    2013-01-01

    Roč. 10, č. 10 (2013), "105814-1"-"105814-4" ISSN 1612-2011 Institutional support: RVO:68378271 Keywords : blue generation * emission * YAlO 3 Subject RIV: BH - Optics, Masers, Lasers Impact factor: 2.964, year: 2013

  8. Generation of more than 300 mW diffraction-limited light at 405 nm by second-harmonic generation of a tapered diode laser with external cavity feedback

    DEFF Research Database (Denmark)

    Jensen, Ole Bjarlin; Holm, J.; Sumpf, B.

    2007-01-01

    We have constructed a blue laser source consisting of a single-frequency tapered diode laser with external cavity feedback that is frequency doubled by a quasi-phase matched KTP (PPKTP) in a bowtie ring cavity and extract more than 360 mW of power at 405 nm. The conversion efficiency from fundame...... fundamental laser power to second harmonic power is 35 %, while it is 64 % from coupled fundamental power to extracted blue light. Thermal effects and gray tracking set an upper limit on the amount of generated blue light.......We have constructed a blue laser source consisting of a single-frequency tapered diode laser with external cavity feedback that is frequency doubled by a quasi-phase matched KTP (PPKTP) in a bowtie ring cavity and extract more than 360 mW of power at 405 nm. The conversion efficiency from...

  9. Nd:YGG crystal laser at 1110 nm: a potential source for detecting carbon monoxide poisoning.

    Science.gov (United States)

    Yu, Haohai; Wu, Kui; Zhang, Huaijin; Wang, Zhengping; Wang, Jiyang; Jiang, Minhua

    2011-04-01

    We demonstrated a laser-diode pumped Nd-doped yttrium gallium garnet crystal laser at 1110 nm for the first time to our knowledge. By suppressing the oscillation at about 1.06 μm, continuous-wave output power of 2.1 W at 1110 nm was achieved. With a Cr:YAG as the saturable absorber, the passive Q-switching performance at this wavelength was obtained. The shortest pulse width and largest pulse energy were 31.5 ns and 22.7 μJ, respectively. Laser radiation at this wavelength is an important source for detecting carbon monoxide poisoning by simple frequency doubling with a nonlinear crystal.

  10. 205 nm continuous-wave laser: application to the measurement of the Lamb shift in hydrogen

    International Nuclear Information System (INIS)

    Bourzeix, S.

    1995-01-01

    The subject of this thesis is the construction of an experimental set-up, and in particular of a tunable continuous-wave laser at 205 nm, for the measurement of the ground state Lamb shift in atomic hydrogen. Chapter 1 deals with the Lamb shift from a historical point of view, and with the interest of its measurement, for metrology and test of quantum electrodynamics. Chapter 2 is devoted to the theory of the hydrogen atom. The principle of the experiment is based on the comparison of two frequencies which are in a ratio of 4: those of the two-photon transitions of 2S-6S or 2S-6D and 1S-3S. Chapter 3 describes the experimental set-up used to measure the 2S-6D transition which is excited by a titanium-sapphire laser at 820 nm. The 205 nm light required to excite the 1S-3S transition is generated by two frequency-doubling of the titanium-sapphire laser, made in non-linear crystals placed in enhancement cavities. Chapter 4 is entirely devoted to the frequency-doubling. After a recall of non-linear optics, the enhancement cavities are described in detail, as well as the results we achieved. At last chapter 5 describes the research for a signal on the 1S-3S transition: the construction of a ground state atomic beam, and the development of the detection system. This work has led to a preliminary measurement of the ground state Lamb shift in atomic hydrogen: L(1S) = 8172.850 (174) MHz whose result is in very good agreement with both the previous measurements and the most recent theoretical results. (author)

  11. Space-Qualified 1064 nm Seed and Metrology Laser Project

    Data.gov (United States)

    National Aeronautics and Space Administration — A space-qualified, single-frequency oscillator operating at 1064 nm is a critical component for a number of active optical measurement systems that have been...

  12. Fiber-based 1150-nm femtosecond laser source for the minimally invasive harmonic generation microscopy

    Science.gov (United States)

    Huang, Jing-Yu; Guo, Lun-Zhang; Wang, Jing-Zun; Li, Tse-Chung; Lee, Hsin-Jung; Chiu, Po-Kai; Peng, Lung-Han; Liu, Tzu-Ming

    2017-03-01

    Harmonic generation microscopy (HGM) has become one unique tool of optical virtual biopsy for the diagnosis of cancer and the in vivo cytometry of leukocytes. Without labeling, HGM can reveal the submicron features of tissues and cells in vivo. For deep imaging depth and minimal invasiveness, people commonly adopt 1100- to 1300-nm femtosecond laser sources. However, those lasers are typically based on bulky oscillators whose performances are sensitive to environmental conditions. We demonstrate a fiber-based 1150-nm femtosecond laser source, with 6.5-nJ pulse energy, 86-fs pulse width, and 11.25-MHz pulse repetition rate. It was obtained by a bismuth borate or magnesium-doped periodically poled lithium niobate (MgO:PPLN) mediated frequency doubling of the 2300-nm solitons, generated from an excitation of 1550-nm femtosecond pulses on a large mode area photonic crystal fiber. Combined with a home-built laser scanned microscope and a tailor-made frame grabber, we achieve a pulse-per-pixel HGM imaging in vivo at a 30-Hz frame rate. This integrated solution has the potential to be developed as a stable HGM system for routine clinical use.

  13. Lasing at 602-620 nm from a red algae-derived phycobiliprotein

    Directory of Open Access Journals (Sweden)

    José A. Rivera

    2017-12-01

    Full Text Available Lasing in the 602-620 nm (orange-red spectral region has been observed from R-phycoerythrin (RPE, a phycobiliprotein responsible for the >80% quantum yield of red algae. Photoexcitation of 8 μM RPE solutions in a Fabry-Pérot resonator with frequency-doubled Nd:YAG laser pulses (λp = 532 nm yields >26 nJ of energy in ∼2.5 ns (FWHM pulses, which corresponds to >10 W of peak power. Maximum laser emission occurs at ∼610 nm, the threshold pump energy fluence is measured to be 260 ± 15 μJ/mm2, and more than 100 longitudinal laser modes are generated when the cavity free spectral range and mirror separation are Δλ = 0.18 nm and L = 777 ± 1 μm, respectively. In combination with the known versatility of the phycobiliproteins as fluorescent tags, the biomolecular RPE laser reported here suggests its applicability to clinical assays and in situ laser imaging.

  14. The efficacy of selective calculus ablation at 400 nm: comparison to conventional calculus removal methods

    Science.gov (United States)

    Schoenly, Joshua E.; Seka, Wolf; Romanos, Georgios; Rechmann, Peter

    A desired outcome of scaling and root planing is the complete removal of calculus and infected root tissue and preservation of healthy cementum for rapid healing of periodontal tissues. Conventional periodontal treatments for calculus removal, such as hand instrument scaling and ultrasonic scaling, often deeply scrape the surface of the underlying hard tissue and may leave behind a smear layer. Pulsed lasers emitting at violet wavelengths (specifically, 380 to 400 nm) are a potential alternative treatment since they can selectively ablate dental calculus without ablating pristine hard tissue (i.e., enamel, cementum, and dentin). In this study, light and scanning electron microscopy are used to compare and contrast the efficacy of in vitro calculus removal for several conventional periodontal treatments (hand instruments, ultrasonic scaler, and Er:YAG laser) to calculus removal with a frequency-doubled Ti:sapphire (λ = 400 nm). After calculus removal, enamel and cementum surfaces are investigated for calculus debris and damage to the underlying hard tissue surface. Compared to the smear layer, grooves, and unintentional hard tissue removal typically found using these conventional treatments, calculus removal using the 400-nm laser is complete and selective without any removal of pristine dental hard tissue. Based on these results, selective ablation from the 400-nm laser appears to produce a root surface that would be more suitable for successful healing of periodontal tissues.

  15. A Randomized, Double-Blind, Placebo-Controlled Clinical Trial Using a Low-Frequency Magnetic Field in the Treatment of Musculoskeletal Chronic Pain

    OpenAIRE

    Alex W Thomas; Karissa Graham; Frank S Prato; Julia McKay; Patricia Morley Forster; Dwight E Moulin; Sesh Chari

    2007-01-01

    Exposure to a specific pulsed electromagnetic field (PEMF) has been shown to produce analgesic (antinociceptive) effects in many organisms. In a randomized, double-blind, sham-controlled clinical trial, patients with either chronic generalized pain from fibromyalgia (FM) or chronic localized musculoskeletal or inflammatory pain were exposed to a PEMF (400 μT) through a portable device fitted to their head during twice-daily 40 min treatments over seven days. The effect of this PEMF on pain re...

  16. Comparison of photosensitivity in germanium doped silica fibers using 244 nm and 266 nm continuous wave lasers

    DEFF Research Database (Denmark)

    Jensen, Jesper Bo; Varming, Poul; Liu, B.

    2001-01-01

    Diode pumped continuous-wave UV lasers offer an interesting alternative to frequency doubled argon-ion lasers. We report the first photosensitivity comparison using these lasers on deuterium loaded standard telecommunication fibers and unloaded experimental fibers.......Diode pumped continuous-wave UV lasers offer an interesting alternative to frequency doubled argon-ion lasers. We report the first photosensitivity comparison using these lasers on deuterium loaded standard telecommunication fibers and unloaded experimental fibers....

  17. Time- and angle-resolved photoemission spectroscopy with optimized high-harmonic pulses using frequency-doubled Ti:Sapphire lasers

    International Nuclear Information System (INIS)

    Eich, S.; Stange, A.; Carr, A.V.; Urbancic, J.; Popmintchev, T.; Wiesenmayer, M.; Jansen, K.; Ruffing, A.; Jakobs, S.; Rohwer, T.; Hellmann, S.; Chen, C.; Matyba, P.; Kipp, L.; Rossnagel, K.; Bauer, M.; Murnane, M.M.; Kapteyn, H.C.; Mathias, S.; Aeschlimann, M.

    2014-01-01

    Highlights: • We present a scheme to generate high intensity XUV pulses from HHG with variable time-bandwidth product. • Shorter-wavelength driven high-harmonic XUV trARPES provides higher photon flux and increased energy resolution. • High-quality high-harmonic XUV trARPES data with sub 150 meV energy and sub 30 fs time resolution is presented. - Abstract: Time- and angle-resolved photoemission spectroscopy (trARPES) using femtosecond extreme ultraviolet high harmonics has recently emerged as a powerful tool for investigating ultrafast quasiparticle dynamics in correlated-electron materials. However, the full potential of this approach has not yet been achieved because, to date, high harmonics generated by 800 nm wavelength Ti:Sapphire lasers required a trade-off between photon flux, energy and time resolution. Photoemission spectroscopy requires a quasi-monochromatic output, but dispersive optical elements that select a single harmonic can significantly reduce the photon flux and time resolution. Here we show that 400 nm driven high harmonic extreme-ultraviolet trARPES is superior to using 800 nm laser drivers since it eliminates the need for any spectral selection, thereby increasing photon flux and energy resolution to <150 meV while preserving excellent time resolution of about 30 fs

  18. Sub-1100 nm lasing from post-growth intermixed InAs/GaAs quantum-dot lasers

    KAUST Repository

    Alhashim, Hala H.

    2015-08-15

    Impurity free vacancy disordering induced highly intermixed InAs/GaAs quantum-dot lasers are reported with high internal quantum efficiency (>89%). The lasers are shown to retain the device characteristics after intermixing and emitting in the important wavelength of ∼1070–1190 nm. The non-coated facet Fabry-Pērot post-growth wavelength tuned lasers exhibits high-power (>1.4W) and high-gain (∼50 cm −1), suitable for applications in frequency doubled green–yellow–orange laser realisation, gas sensing, metrology etc.

  19. A Randomized, Double-Blind, Placebo-Controlled Clinical Trial Using a Low-Frequency Magnetic Field in the Treatment of Musculoskeletal Chronic Pain

    Directory of Open Access Journals (Sweden)

    Alex W Thomas

    2007-01-01

    Full Text Available Exposure to a specific pulsed electromagnetic field (PEMF has been shown to produce analgesic (antinociceptive effects in many organisms. In a randomized, double-blind, sham-controlled clinical trial, patients with either chronic generalized pain from fibromyalgia (FM or chronic localized musculoskeletal or inflammatory pain were exposed to a PEMF (400 μT through a portable device fitted to their head during twice-daily 40 min treatments over seven days. The effect of this PEMF on pain reduction was recorded using a visual analogue scale. A differential effect of PEMF over sham treatment was noticed in patients with FM, which approached statistical significance (P=0.06 despite low numbers (n=17; this effect was not evident in those without FM (P=0.93; n=15. PEMF may be a novel, safe and effective therapeutic tool for use in at least certain subsets of patients with chronic, nonmalignant pain. Clearly, however, a larger randomized, double-blind clinical trial with just FM patients is warranted.

  20. A randomized, double-blind, placebo-controlled clinical trial using a low-frequency magnetic field in the treatment of musculoskeletal chronic pain

    Science.gov (United States)

    Thomas, Alex W; Graham, Karissa; Prato, Frank S; McKay, Julia; Forster, Patricia Morley; Moulin, Dwight E; Chari, Sesh

    2007-01-01

    Exposure to a specific pulsed electromagnetic field (PEMF) has been shown to produce analgesic (antinociceptive) effects in many organisms. In a randomized, double-blind, sham-controlled clinical trial, patients with either chronic generalized pain from fibromyalgia (FM) or chronic localized musculoskeletal or inflammatory pain were exposed to a PEMF (400 μT) through a portable device fitted to their head during twice-daily 40 min treatments over seven days. The effect of this PEMF on pain reduction was recorded using a visual analogue scale. A differential effect of PEMF over sham treatment was noticed in patients with FM, which approached statistical significance (P=0.06) despite low numbers (n=17); this effect was not evident in those without FM (P=0.93; n=15). PEMF may be a novel, safe and effective therapeutic tool for use in at least certain subsets of patients with chronic, nonmalignant pain. Clearly, however, a larger randomized, double-blind clinical trial with just FM patients is warranted. PMID:18080043

  1. Transformation frequency of γ irradiated plasmid DNA and the enzymatic double strand break formation by incubation in a protein extract of Escherichia coli

    International Nuclear Information System (INIS)

    Schulte-Frohlinde, D.; Mark, F.; Ventur, Y.

    1994-01-01

    It was found that incubation of γ-irradiated or DNaseI-treated plasmid DNA in a protein extract of Escherichia coli leads to enzyme-induced formation of double strand breaks (dsb) in competition with repair of precursors of these dsb. A survival curve of the plasmid DNA (as determined by transformation of E. coli) was calculated on the basis of enzyme-induced dsb as well as those produced by irradiation assuming that they are lethal. The calculated D O value was the same as that measured directly by transformation of irradiated plasmid DNA. Two models are presented that fit the experimental survival data as a function of dose. One is based on damage formation in the plasmid DNA including enzymatic conversion of single strand damage into dsb (U-model), the other is an enzymatic repair saturation model based on Michaelis-Menten kinetics. (Author)

  2. Transformation frequency of [gamma] irradiated plasmid DNA and the enzymatic double strand break formation by incubation in a protein extract of Escherichia coli

    Energy Technology Data Exchange (ETDEWEB)

    Schulte-Frohlinde, D.; Mark, F.; Ventur, Y. (Max-Planck-Institut fuer Strahlenchemie, Muelheim an der Ruhr (Germany))

    1994-01-01

    It was found that incubation of [gamma]-irradiated or DNaseI-treated plasmid DNA in a protein extract of Escherichia coli leads to enzyme-induced formation of double strand breaks (dsb) in competition with repair of precursors of these dsb. A survival curve of the plasmid DNA (as determined by transformation of E. coli) was calculated on the basis of enzyme-induced dsb as well as those produced by irradiation assuming that they are lethal. The calculated D[sub O] value was the same as that measured directly by transformation of irradiated plasmid DNA. Two models are presented that fit the experimental survival data as a function of dose. One is based on damage formation in the plasmid DNA including enzymatic conversion of single strand damage into dsb (U-model), the other is an enzymatic repair saturation model based on Michaelis-Menten kinetics. (Author).

  3. Renormalized phonon frequencies and electric resistivity along the c-axis in single-plane high-temperature superconductors: A double-well analysis

    CERN Document Server

    Georgiev, M; Polyanski, I; Petrova, P T; Tsintsarska, S; Gochev, A

    2001-01-01

    We consider the dynamic interlayer charge transfer across apex oxygens between CuO sub 2 planes in single-layered high-T sub c superconductors. Phonon-coupled axial transfer rates are derived by means of the reaction-rate method. They lead straightforwardly to temperature dependences for the axial resistivity. Doping and temperature dependences are also derived for the renormalized frequencies of phonon modes coupled to the interlayer charge transfer. Our results are compared with experimentally observed dependences. (author)

  4. Laser–fibre vibrometry at 1550 nm

    International Nuclear Information System (INIS)

    Waz, A T; Kaczmarek, P R; Abramski, K M

    2009-01-01

    This paper presents new solutions for laser vibrometry, which are based on fibre vibrometry in the third telecommunication window. The scattered laser beam from a vibrating object is guided by a fibre collimator and coherently detected through heterodyning it with an acousto-optical frequency-shifted reference beam. The concept of measuring vibration parameters from many points of the vibrating object has been inspired by wavelength division multiplexing (WDM) in fibre telecommunications. The N-independent WDM separated 15XX nm fibre-coupled laser diodes (used for optical fibre telecommunications) form a system of sources for multipoint vibration measurement according to the rule 'one wavelength–one point'

  5. Characterization of post mortem arterial tissue using time-resolved photoacoustic spectroscopy at 436, 461 and 532 nm

    Science.gov (United States)

    Beard, P. C.; Mills, T. N.

    1997-01-01

    Time-resolved photoacoustic spectroscopy has been used to characterize post mortem arterial tissue for the purpose of discriminating between normal and atheromatous areas of tissue. Ultrasonic thermoelastic waves were generated in post mortem human aorta by the absorption of nanosecond laser pulses at 436, 461 and 532 nm produced by a frequency doubled Q-switched Nd:YAG laser in conjunction with a gas filled Raman cell. A PVDF membrane hydrophone was used to detect the thermoelastic waves. At 436 nm, differences in the photoacoustic signatures of normal tissue and atherorma were found to be highly variable. At 461 nm, there was a clear and reproducible difference between the photacoustic response of atheroma and normal tissue as a result of increased optical attenuation in atheroma. At 532 nm, the generation of subsurface thermoelastic waves provided a means of determining the structure and thickness of the tissue sample. It is suggested that pulsed photoacoustic spectroscopy at 461 and 532 nm may find application in characterizing arterial tissue in situ by providing information about both the composition and thickness of the vessel wall.

  6. Shifted excitation resonance Raman difference spectroscopy using a microsystem light source at 488 nm

    Science.gov (United States)

    Maiwald, M.; Sowoidnich, K.; Schmidt, H.; Sumpf, B.; Erbert, G.; Kronfeldt, H.-D.

    2010-04-01

    Experimental results in shifted excitation resonance Raman difference spectroscopy (SERRDS) at 488 nm will be presented. A novel compact diode laser system was used as excitation light source. The device is based on a distributed feedback (DFB) diode laser as a pump light source and a nonlinear frequency doubling using a periodically poled lithium niobate (PPLN) waveguide crystal. All elements including micro-optics are fixed on a micro-optical bench with a footprint of 25 mm × 5 mm. An easy temperature management of the DFB laser and the crystal was used for wavelength tuning. The second harmonic generation (SHG) provides an additional suppression of the spontaneous emission. Raman spectra of polystyrene demonstrate that no laser bandpass filter is needed for the Raman experiments. Resonance-Raman spectra of the restricted food colorant Tartrazine (FD&C Yellow 5, E 102) in distilled water excited at 488 nm demonstrate the suitability of this light source for SERRDS. A limit of detection (LOD) of 0.4 μmol.l-1 of E102 enables SERRDS at 488 nm for trace detection in e.g. food safety control as an appropriate contactless spectroscopic technique.

  7. Wavelength dependence on the forensic analysis of glass by nanosecond 266 nm and 1064 nm laser induced breakdown spectroscopy

    International Nuclear Information System (INIS)

    Cahoon, Erica M.; Almirall, Jose R.

    2010-01-01

    Laser induced breakdown spectroscopy can be used for the chemical characterization of glass to provide evidence of an association between a fragment found at a crime scene to a source of glass of known origin. Two different laser irradiances, 266 nm and 1064 nm, were used to conduct qualitative and quantitative analysis of glass standards. Single-pulse and double-pulse configurations and lens-to-sample-distance settings were optimized to yield the best laser-glass coupling. Laser energy and acquisition timing delays were also optimized to result in the highest signal-to-noise ratio corresponding to the highest precision and accuracy. The crater morphology was examined and the mass removed was calculated for both the 266 nm and 1064 nm irradiations. The analytical figures of merit suggest that the 266 nm and 1064 nm wavelengths are capable of good performance for the forensic chemical characterization of glass. The results presented here suggest that the 266 nm laser produces a better laser-glass matrix coupling, resulting in a better stoichiometric representation of the glass sample. The 266 nm irradiance is therefore recommended for the forensic analysis and comparison of glass samples.

  8. 205 nm continuous-wave laser: application to the measurement of the Lamb shift in hydrogen; Laser continu a 205 nm: application a la mesure du deplacement de lamb dans l'hydrogene

    Energy Technology Data Exchange (ETDEWEB)

    Bourzeix, S

    1995-01-15

    The subject of this thesis is the construction of an experimental set-up, and in particular of a tunable continuous-wave laser at 205 nm, for the measurement of the ground state Lamb shift in atomic hydrogen. Chapter 1 deals with the Lamb shift from a historical point of view, and with the interest of its measurement, for metrology and test of quantum electrodynamics. Chapter 2 is devoted to the theory of the hydrogen atom. The principle of the experiment is based on the comparison of two frequencies which are in a ratio of 4: those of the two-photon transitions of 2S-6S or 2S-6D and 1S-3S. Chapter 3 describes the experimental set-up used to measure the 2S-6D transition which is excited by a titanium-sapphire laser at 820 nm. The 205 nm light required to excite the 1S-3S transition is generated by two frequency-doubling of the titanium-sapphire laser, made in non-linear crystals placed in enhancement cavities. Chapter 4 is entirely devoted to the frequency-doubling. After a recall of non-linear optics, the enhancement cavities are described in detail, as well as the results we achieved. At last chapter 5 describes the research for a signal on the 1S-3S transition: the construction of a ground state atomic beam, and the development of the detection system. This work has led to a preliminary measurement of the ground state Lamb shift in atomic hydrogen: L(1S) = 8172.850 (174) MHz whose result is in very good agreement with both the previous measurements and the most recent theoretical results. (author)

  9. Acute effects of high-frequency microfocal vibratory stimulation on the H reflex of the soleus muscle. A double-blind study in healthy subjects.

    Science.gov (United States)

    Alfonsi, Enrico; Paone, Paolo; Tassorelli, Cristina; De Icco, Roberto; Moglia, Arrigo; Alvisi, Elena; Marchetta, Lucky; Fresia, Mauro; Montini, Alessandra; Calabrese, Marzia; Versiglia, Vittorio; Sandrini, Giorgio

    2015-01-01

    This study in healthy subjects examined the effects of a system delivering focal microvibrations at high frequency (Equistasi®) on tonic vibration stimulus (TVS)-induced inhibition of the soleus muscle H reflex. Highfrequency microvibrations significantly increased the inhibitory effect of TVS on the H reflex for up to three minutes. Moreover, Equistasi® also significantly reduced alpha-motoneuron excitability, as indicated by the changes in the ratio between the maximumamplitude H reflex (Hmax reflex) and the maximumamplitude muscle response (Mmax response); this effect was due to reduction of the amplitude of the H reflex because the amplitude of muscle response remained unchanged. The present findings indicate that Equistasi® has a modulatory effect on proprioceptive reflex circuits. Therefore, Equistasi® might interfere with some mechanisms involved in both physiological and pathophysiological control of movement and of posture.

  10. Effects of TRPV1 and TRPA1 activators on the cramp threshold frequency: a randomized, double-blind placebo-controlled trial.

    Science.gov (United States)

    Behringer, Michael; Nowak, Stephanie; Leyendecker, Jannik; Mester, Joachim

    2017-08-01

    Previous data indicate that a strong sensory input from orally administered TRPV1 and TRPA1 activators alleviates muscle cramps in foot muscles by reducing the α-motor neuron hyperexcitability. We investigated if TRP activators increase the cramp threshold frequency of the medial gastrocnemius. We randomly assigned 22 healthy male participants to an intervention (IG) and a control group (CG). While participants of the IG ingested a mixture of TRPV1 and TRPA1 activators, the CG received a placebo. We tested the cramp threshold frequency (CTF), the cramp intensity (EMG activity), and the perceived pain of electrically induced muscle cramps before (pre), and 15 min, 4, 8, and 24 h after either treatment. We further measured the maximal isometric force of knee extensors at pre, 4, and 24 h to assess potential side-effects on the force output. When we included all measurement time points, no group-by-time interaction was observed for the CTF. However, when only pre and 15 min values were incorporated, a significant interaction, with a slightly greater CTF increase in IG (3.1 ± 1.5) compared to the CG (2.0 ± 1.5), was observed. No significant group by time interaction was found for the cramp intensity, the perceived pain, and the maximal isometric force. Our data indicate that orally administered TRPV1 and TRPA1 activators exert a small short-term effect on the CTF, but not on the other parameters tested. Future studies need to investigate whether such small CTF increments are sufficient to prevent exercise-associated muscle cramps.

  11. High frequency of the aac(6')-Ib-cr gene associated with double mutations in gyrA and parC in Escherichia coli isolates from patients with urinary tract infections.

    Science.gov (United States)

    Volcão, Lisiane M; Lacava, Juliano P; Gewehr, Martina F; Real, Valéria L; Ramis, Ivy B; Ramos, Daniela F; Gonçalves, Carla V; Possuelo, Lia G; Minarini, Luciene A R; da Silva, Pedro E A; von Groll, Andrea

    2018-01-04

    The aims of this study were (1) to determine the frequency of plasmid-mediated resistance to fluoroquinolones (FQs) in Escherichia coli isolated from patients with urinary tract infections (UTIs) of nosocomial and community origin and (2) to determine the relationships between the presence of extended spectrum beta lactamases (ESBL), mutations in the gyrA and parC genes, and resistance to FQs. A total of 71 E. coli isolates, including 35 ESBL producers and 36 randomly selected non-ESBL-producers, were analysed. The aac(6')-Ib gene was amplified using PCR and subsequently digested with the BtsCl restriction enzyme to identify aac(6')-Ib-cr, a variant associated with FQ resistance. The detection of the qnr genes was performed using multiplex PCR. In isolates that tested positive for these genes, the gyrA and parC genes were sequenced and the modulation factor of an efflux pump inhibitor (EPI) was determined on the minimal inhibitory concentration (MIC) of norfloxacin. The frequencies of qnrS, qnrB and qnrA were 4.2%, 2.8%, and 0%, respectively. The frequency of aac(6')-Ib-cr was 40.8% and this variant was associated with double mutations in gyrA and parC as well as resistance to FQs and ESBL production. Modulation of EPI activity was more frequent in resistant isolates, which had wild-type parC gene. An interplay of resistance mechanisms increased the level of resistance to FQs and the high frequency of putative plasmid-mediated quinolone resistance genes associate with ESBL producer reduced therapeutic options to treat UTIs in the affected population. Copyright © 2018. Published by Elsevier Ltd.

  12. Effect of 0.2% Chlorhexidine Gel on Frequency of Dry Socket Following Mandibular Third Molar Surgery: A Double-Blind Clinical Trial Clinical Trial

    Directory of Open Access Journals (Sweden)

    Baratollah Shaban

    2014-09-01

    Full Text Available Introduction: Alveolar osteitis (AO is one of the most common postoperative complications after third molar surgery. Various techniques have been used to reduce the risk of AO. The aim of the current study was to evaluate the effect of Chlorhexidine (CHX bioadhesive gel in preventing the development of AO. Methods: Patients with bilateral impacted mandibular third molars underwent surgical extraction of both teeth. One socket was randomly received CHX gel and the contralateral socket served as the control. The outcome variable was development of AO and the CHX gel application was the predictor variable. Data were analyzed using chi-square test with the confidence interval of 95%. Results: 41 patients (27 females and 14 males with mean age of 24.15 ± 5.02 years underwent 82 surgeries. Total of 11 sockets (13.41% developed AO. The frequency of AO in CHX gel (2 cases, 4.87% side was significantly lower than control (9 cases, 21.95% side (P-value < 0.05. No side effects observed following CHX gel application. Conclusion: Application of CHX gel could be an effective approach to reduce the risk of developing AO following mandibular third molar surgery.

  13. On the impact of a doubled sampling frequency on the detection capability and accuracy of a xenon station at the example of the German IMS RN station Schauinsland

    Science.gov (United States)

    Becker, Andreas; Schlosser, Clemens; Auer, Matthias; Gohla, Herbert; Kumberg, Timo; Wernsperger, Bernd

    2010-05-01

    associated higher variable wind fields impose a higher demand on the temporal resolution of the monitoring and the associated source region attribution provided by inversion modelling based on sample specific backtracking results. This study deals with the impact on the regional xenon detection and source location and attribution capability of the IMS radionuclide station No.33 (Schauinsland, Germany) encountered and analysed for a year 2009 period where the acquisition time of a xenon sampling system was halved yielding two 12h samples instead of one 24h sample per day. It is investigated whether the positive impact of the higher frequency of sampling that allows for the first time to roughly resolve diurnal variations of the meteorological fields is over-compensated by the adverse effects to the detection limit due to an enlarged minimum detectable concentration of the noble gas system SPALAX in use. Higher temporal resolution at worsened detection limit potentially leads to a different measured composition of known radioxenon emitters that can be attributed to the xenon detections encountered, as the detections from local sources possibly resolved the first time due to the higher sampling frequency might be compensated by loss of signals from weak or persistent emitters due to the higher detection limit. Therefore, the potentially different monitoring fingerprints of the station operated at 12 and 24h acquisition times are discussed. The result of this case study could have influence on further improvements of the detection capability of equipment and requirements for the Atmospheric Transport Modelling to generally increase the detection capability of the noble gas network.

  14. Effect of Low-Frequency Repetitive Transcranial Magnetic Stimulation on Naming Abilities in Early-Stroke Aphasic Patients: A Prospective, Randomized, Double-Blind Sham-Controlled Study

    Directory of Open Access Journals (Sweden)

    Konrad Waldowski

    2012-01-01

    Full Text Available Background and Purpose. Functional brain imaging studies with aphasia patients have shown increased cortical activation in the right hemisphere language homologues, which hypothetically may represent a maladaptive strategy that interferes with aphasia recovery. The aim of this study was to investigate whether low-frequency repetitive transcranial magnetic stimulation (rTMS over the Broca’s homologues in combination with speech/language therapy improves naming in early-stroke aphasia patients. Methods. 26 right-handed aphasic patients in the early stage (up to 12 weeks of a first-ever left hemisphere ischemic stroke were randomized to receive speech and language therapy combined with real or sham rTMS. Prior to each 45-minute therapeutic session (15 sessions, 5 days a week, 30 minutes of 1-Hz rTMS was applied. Outcome measures were obtained at baseline, immediately after 3 weeks of experimental treatment and 15 weeks; posttreatment using the Computerized Picture Naming Test. Results. Although both groups significantly improved their naming abilities after treatment, no significant differences were noted between the rTMS and sham stimulation groups. The additional analyses have revealed that the rTMS subgroup with a lesion including the anterior part of language area showed greater improvement primarily in naming reaction time 15 weeks after completion of the therapeutic treatment. Improvement was also demonstrated in functional communication abilities. Conclusions. Inhibitory rTMS of the unaffected right inferior frontal gyrus area in combination with speech and language therapy cannot be assumed as an effective method for all poststroke aphasia patients. The treatment seems to be beneficial for patients with frontal language area damage, mostly in the distant time after finishing rTMS procedure.

  15. Efficacy of treatment of insomnia in migraineurs with eszopiclone (Lunesta®) and its effect on total sleep time, headache frequency, and daytime functioning: A randomized, double-blind, placebo-controlled, parallel-group, pilot study.

    Science.gov (United States)

    Spierings, Egilius L H; McAllister, Peter J; Bilchik, Tanya R

    2015-04-01

    A review on headache and insomnia revealed that insomnia is a risk factor for increased headache frequency and headache intensity in migraineurs. The authors designed a randomized, double blind, placebo-controlled, parallel-group, pilot study in which migraineurs who also had insomnia were enrolled, to test this observation. In the study, the authors treated 79 subjects with IHS-II migraine with and/or without aura and with DSM-IV primary insomnia for 6 weeks with 3 mg eszopiclone (Lunesta(®)) or placebo at bedtime. The treatment was preceded by a 2-week baseline period and followed by a 2-week run-out period. Of the 79 subjects treated, 75 were evaluable, 35 in the eszopiclone group, and 40 in the placebo group. At baseline, the groups were comparable except for sleep latency. Of the three remaining sleep variables, total sleep time, nighttime awakenings, and sleep quality, the number of nighttime awakenings during the 6-week treatment period was significantly lower in the eszopiclone group than in the placebo group (P = 0.03). Of the three daytime variables, alertness, fatigue, and functioning, this was also the case for fatigue (P = 005). The headache variables, frequency, duration, and intensity, did not show a difference from placebo during the 6-week treatment period. The study did not meet primary endpoint, that is, the difference in total sleep time during the 6-week treatment period between eszopiclone and placebo was less than 40 minutes. Therefore, it failed to answer the question as to whether insomnia is, indeed, a risk factor for increased headache frequency and headache intensity in migraineurs.

  16. Comparison of 1470nm diode laser vs. C02-laserlaser for tonsillotomy and a clinical feasability trial on the use of 1940nm in ENT

    Science.gov (United States)

    Sroka, Ronald; Pongratz, Thomas; Havel, Miriam; Englert, Elsa; Kremser, Thomas; Betz, Christain S.; Leunig, Andreas

    2013-03-01

    Introduction: The need for reduction of post-tonsillectomy hemorrhage has led to promotion of tonsillotomy techniques for tonsil tissue reduction in obstructive tonsillar hypertrophy. A first study compares ablative tissue effects using 1470nm diode laser and CO2-laser for tonsillotomy in an intraindividual design. A number of different laser systems have been used for volume reduction of hyperplastic nasal turbinates. The aim of a 2nd clinical feasibility study was to show the coagulative and tissue reducing effects using a novel Tm: fiber laser system emitting at λ = 1940 nm Patients and methods: First 21 children aged 3 -13 years (mean age 6.3 years) underwent laser tonsillotomy for obstructive tonsillar hypertrophy in this double blind, prospective, randomized, clinical feasibility trial. In each case, tonsillotomy was performed using fibre guided 1470nm diode laser (contact mode, 15 W power) on the one side and CO2-laser (12 W power) on the other side. An independent physician documented clinical presentation and patients' symptoms preoperatively and on day 1, 3, 7, 14 and 21 postoperatively using standardized questionnaire including VAS (was ist das) for each side separately. The 2nd clinical feasibility trial included 11 patients suffering from hyperplastic inferior nasal turbinates, who were therapy-refractory to conservative medical treatment. The obstructive nasal cavity was treated using the 1940 nm Tm: fiber laser at < 5 W output power. The treatment was performed in non-contact mode under endoscopic control. Patients ' symptoms were documented both preoperatively and on days 1 - 3 and 28 postoperatively using a non-validated questionnaire. Additionally, an endoscopic examination was performed. Results: Mean duration of single tonsillotomy operative treatment was 2.7 min using 1470nm laser and 4.9 min using CO2 laser respectively. Intraoperative bleeding and the frequency of bipolar forceps use for intraoperative bleeding control was significantly less

  17. A diode-laser optical frequency standard based on laser-cooled Ca atoms: sub-kilohertz spectroscopy by optical shelving detection

    International Nuclear Information System (INIS)

    Oates, C.W.; Bondu, F.; Fox, R.W.; Hollberg, L.

    1999-01-01

    We report an optical frequency standard at 657 nm based on laser-cooled/trapped Ca atoms. The system consists of a novel, compact magneto-optic trap which uses 50 mW of frequency-doubled diode laser light at 423 nm and can trap >10 7 Ca atoms in 20 ms. High resolution spectroscopy on this atomic sample using the narrow 657 nm intercombination line resolves linewidths (FWHM) as narrow as 400 Hz, the natural linewidth of the transition. The spectroscopic signal-to-noise ratio is enhanced by an order of magnitude with the implementation of a ''shelving'' detection scheme on the 423 nm transition. Our present apparatus achieves a fractional frequency instability of 5 x 10 -14 in 1 s with a potential atom shot-noise-limited performance of 10 -16 τ -1/2 and excellent prospects for high accuracy. (orig.)

  18. Double Trouble

    NARCIS (Netherlands)

    Elsaesser, Thomas; Kievit, Robert; Simons, Jan

    1994-01-01

    Double Trouble highlights the career of Dutch scriptwriter and television producer Chiem van Houweninge, well-known for his long-running TV comedy series and as author of episodes for TV detective series. Double Trouble gives Van Houweninge's own views on writing and filming in television prime

  19. Frequency-modulation transient absorption spectrum of the HCCl A 1A double-prime(0,0,0)left-arrow X 1A'(0,0,0) transition

    International Nuclear Information System (INIS)

    Chang, B.; Sears, T.J.

    1995-01-01

    The rotationally resolved spectrum of the HCCl A 1 A double-prime(0,0,0)left-arrow X 1 A'(0,0,0) transition between 12 230 and 12 410 cm -1 was obtained for the first time at Doppler-limited resolution using a frequency-modulation (FM) transient absorption technique. Five major subbands (K a =0 left-arrow 1, 1 left-arrow 0, 1 left-arrow 2, 2 left-arrow 1, and 2 left-arrow 3) of HC 35 Cl and one subband (K a =0 left-arrow 1) of HC 37 Cl were observed and assigned. In addition, the forbidden subband (K a =0 left-arrow 0) of HC 35 Cl was also observed. Thus far, we have assigned most (more than 70%) of the strong lines. The analysis of these subbands determines the geometry for the HCCl A(0,0,0) level: angle HCCl=134.7 degree and R C-Cl =1.623 A while R C-H is fixed at the corresponding value of CH 2 . The height of the barrier to linearity was found to be approximately 2170 cm -1 above the vibrationless level of the A state. The rotational structure of this spectrum shows irregular perturbations. Both random and J-dependent (anomalous K-type doubling) effects were observed. As in methylene, the perturbations most likely arise from Renner--Teller effect between the two singlet states in combination with spin--orbit coupling between the singlet and triplet states

  20. Double-Edge Molecular Technique for Doppler Lidar Wind Measurement

    Science.gov (United States)

    Flesia, Cristina; Korb, C. Laurence

    1998-01-01

    The double-edge lidar technique for measuring the wind using molecular backscatter is described. Two high spectral resolution edge filters are located in the wings of the Rayleigh-Brillouin profile. This doubles the signal change per unit Doppler shift, the sensitivity, and gives nearly a factor of two improvement in measurement accuracy. The use of a crossover region is described where the sensitivity of a molecular and aerosol-based measurement are equal. This desensitizes the molecular measurement to the effects of aerosol scattering over a frequency range of +/- 100 m/s. We give methods for correcting for short-term frequency jitter and drift using a laser reference frequency measurement and methods for long-term frequency correction using a servo control system. The effects of Rayleigh-Brillouin scattering on the measurement are shown to be significant and are included in the analysis. Simulations for a conical scanning satellite-based lidar at 355 nm show an accuracy of 2-3 m/s for altitudes of 2 to 15 km for a 1 km vertical resolution, a satellite altitude of 400 km and a 200 km x 200 km spatial resolution. Results of ground based wind measurements are presented.

  1. Double-edge molecular technique for Doppler lidar wind measurement

    Science.gov (United States)

    Flesia, Cristina; Korb, C. L.

    1998-08-01

    The double-edge lidar technique for measuring the wind based upon using molecular backscatter is described. The technique uses two high spectral resolution edge filters which are located in the wings of the Rayleigh-Brillouin profile. This doubles the signal change per unit Doppler shift, the sensitivity, and gives nearly a factor of two improvement in measurement accuracy relative to the single edge technique. The use of a crossover region is described where the sensitivity of a molecular and aerosol-based measurement are equal. This desensitizes the molecular measurement to the effects of aerosol scattering over a frequency range of plus or minus 100 m/s. We give methods for correcting for short- term, shot to shot, frequency jitter and drift using a laser reference frequency measurement and methods for long-term frequency correction using a servo control system. The effects of Rayleigh-Brillouin scattering on the measurement are shown to be significant and are included in the analysis. Simulations for a conical scanning satellite-based lidar at 355 nm show an accuracy of 2 - 3 m/s for altitudes of 2 to 15 km for a 1 km vertical resolution, a satellite altitude of 400 km and a 200 km X 200 km spatial resolution. Results for recent wind measurements, which show an accuracy of 1 m/s up to an altitude of 10 km, are given.

  2. Diode-pumped continuous-wave blue laser operation of Nd:GGG at 467.0, 467.7, and 468.5 nm

    International Nuclear Information System (INIS)

    Xu, B; Camy, P; Doualan, J L; Braud, A; Moncorgé, R; Cai, Z P; Brenier, A

    2012-01-01

    Intra-cavity frequency doubling of continuous-wave (CW) laser emission on the quasi-three level ( 4 F 3/2 → 4 I 9/2 ) laser transition of Nd 3+ in Nd:GGG is reported by using a three-mirror folded resonator. The thermal lens experienced by the optically-pumped Nd:GGG laser crystal is measured as a function of the absorbed pump power and compared to that found, in the same conditions, in the case of Nd:YAG. Results are interpreted by using a simple model accounting for the absorbed pump power and the thermo-mechanical properties of each laser crystal. Diode-pumped blue laser operation is achieved, for the first time, at 467.0 and 468.5 nm with output powers of 230 and 450 mW, respectively. Simultaneous laser operation resulting both from frequency-doubling and frequency summing at the three 467.1, 467.7, and 468.1 nm laser wavelengths is also obtained with a total output power of 60 mW

  3. Ytterbium‐doped distributed spectral filtering photonic crystal fibers for use at wavelengths above 1100 nm

    DEFF Research Database (Denmark)

    Petersen, Sidsel Rübner; Alkeskjold, Thomas Tanggaard; Lægsgaard, Jesper

    Rare‐earth doped high‐power fiber lasers and amplifiers have attracted a lot of attention, due to the advantages of the fiber amplification scheme. Compared to conventional optically pumped bulk lasers, heat is dissipated much more effectively in fiber lasers, having a large surface‐to‐active vol......, and SM behaviour is demonstrated for core diameters of ~ 45 μm. Redshifting of the maximum gain from 1030 nm to above 1100 nm is illustrated by considering the Ytterbium gain curve and a white light transmission measurement of the PCF....... can reach the yellow‐orange light regime through frequency doubling. Yellow‐orange light has applications within the medical industry, high‐resolution spectroscopy and for laser‐guide stars [2]. To achieve amplification at these wavelengths, the larger gain at shorter wavelengths must be suppressed...... to avoid parasitic lasing due to Amplified Spontaneous Emission (ASE) build‐up. Nonlinear effects, such as stimulated Raman scattering, stimulated Brillouin scattering and four‐wave mixing, set the upper limit for achievable powers in fiber amplifiers. To increase the nonlinear threshold, Large...

  4. Generation of spectrally-stable continuous-wave emission and ns pulses at 800 nm and 975 nm with a peak power of 4 W using a distributed Bragg reflector laser and a ridge-waveguide power amplifier

    Science.gov (United States)

    Klehr, A.; Wenzel, H.; Fricke, J.; Bugge, F.; Liero, A.; Hoffmann, Th.; Erbert, G.; Tränkle, G.

    2015-03-01

    Semiconductor based sources which emit high-power spectrally stable nearly diffraction-limited optical pulses in the nanosecond range are ideally suited for a lot of applications, such as free-space communications, metrology, material processing, seed lasers for fiber or solid state lasers, spectroscopy, LIDAR and frequency doubling. Detailed experimental investigations of 975 nm and 800 nm diode lasers based on master oscillator power amplifier (MOPA) light sources are presented. The MOPA systems consist of distributed Bragg reflector lasers (DBR) as master oscillators driven by a constant current and ridge waveguide power amplifiers which can be driven DC and by current pulses. In pulse regime the amplifiers modulated with rectangular current pulses of about 5 ns width and a repetition frequency of 200 kHz act as optical gates, converting the continuous wave (CW) input beam emitted by the DBR lasers into a train of short optical pulses which are amplified. With these experimental MOPA arrangements no relaxation oscillations in the pulse power occur. With a seed power of about 5 mW at a wavelength of 973 nm output powers behind the amplifier of about 1 W under DC injection and 4 W under pulsed operation, corresponding to amplification factors of 200 (amplifier gain 23 dB) and 800 (gain 29 dB) respectively, are reached. At 800 nm a CW power of 1 W is obtained for a seed power of 40 mW. The optical spectra of the emission of the amplifiers exhibit a single peak at a constant wavelength with a line width 50 dB. The output beams are nearly diffraction limited with beam propagation ratios M2lat ~ 1.1 and M2ver ~ 1.2 up to 4 W pulse power.

  5. Optical frequency comb for high resolution hydrogen spectroscopy

    International Nuclear Information System (INIS)

    Arnoult, O.

    2006-11-01

    In this work, we perform an absolute frequency measurement of the 1S-3S transition in atomic hydrogen, in order to improve the uncertainties on both the Rydberg constant and the Lamb shift L1S. In the experiment, a CW stabilized Ti:Sa laser is doubled twice in LBO (LiB 3 O 5 ) and BBO (β-BaB 2 O 4 ) crystals. The 1S-3S transition is excited by two photons at 205 nm in an optical cavity colinear with the atomic beam, at room temperature. The remaining second-order Doppler effect is compensated by a quadratic Stark effect resulting from an applied static magnetic field. An optical frequency comb is used to compare directly the Ti:Sa frequency with the microwave frequency standard. We detect fluorescence at 656 nm thanks to a CCD camera. Fitting the experimental data with our calculated line shapes leads to a value of the second-order Doppler effect in disagreement with approximative predictions for the 1S-3S frequency. We suggest the existence of stray electric fields as a possible systematic effect. The slides of the defence of the thesis have been added at the end of the document. (author)

  6. Cost-effective tunable 1310nm DWDM transmitter

    Science.gov (United States)

    Chorchos, Łukasz; Turkiewicz, Jarosław P.

    2015-09-01

    The growing demand for higher data rate transmissions in local and metropolitan area networks is main reason of developing effective and inexpensive transmission systems. In this paper, study about the possibility to realize 1310 nm tunable DWDM transmitter using commercially available low-cost DFB lasers is presented. Extensive DFB lasers characterization has been performed which led to establish relationships between laser current, operational temperature, emitted wavelength and power. An algorithm to find the laser settings for a desired wavelength grid has been proposed and tested. Generation of the 1310nm DWDM channels with frequency spacing between 120 and 240GHz has been demonstrated.

  7. FDML swept source at 1060 nm using a tapered amplifier

    DEFF Research Database (Denmark)

    Marschall, Sebastian; Klein, Thomas; Wieser, Wolfgang

    2010-01-01

    We present a novel frequency-swept light source working at 1060nm that utilizes a tapered amplifier as gain medium. These devices feature significantly higher saturation power than conventional semiconductor optical amplifiers and can thus improve the limited output power of swept sources...... in this wavelength range. We demonstrate that a tapered amplifier can be integrated into a fiber-based swept source and allows for high-speed FDML operation. The developed light source operates at a sweep rate of 116kHz with an effective average output power in excess of 30mW. With a total sweep range of 70 nm...

  8. Frequency comb swept lasers.

    Science.gov (United States)

    Tsai, Tsung-Han; Zhou, Chao; Adler, Desmond C; Fujimoto, James G

    2009-11-09

    We demonstrate a frequency comb (FC) swept laser and a frequency comb Fourier domain mode locked (FC-FDML) laser for applications in optical coherence tomography (OCT). The fiber-based FC swept lasers operate at a sweep rate of 1kHz and 120kHz, respectively over a 135nm tuning range centered at 1310nm with average output powers of 50mW. A 25GHz free spectral range frequency comb filter in the swept lasers causes the lasers to generate a series of well defined frequency steps. The narrow bandwidth (0.015nm) of the frequency comb filter enables a approximately -1.2dB sensitivity roll off over approximately 3mm range, compared to conventional swept source and FDML lasers which have -10dB and -5dB roll offs, respectively. Measurements at very long ranges are possible with minimal sensitivity loss, however reflections from outside the principal measurement range of 0-3mm appear aliased back into the principal range. In addition, the frequency comb output from the lasers are equally spaced in frequency (linear in k-space). The filtered laser output can be used to self-clock the OCT interference signal sampling, enabling direct fast Fourier transformation of the fringe signals, without the need for fringe recalibration procedures. The design and operation principles of FC swept lasers are discussed and designs for short cavity lasers for OCT and interferometric measurement applications are proposed.

  9. Design and modeling of an all-optical frequency modulated MEMS strain sensor using nanoscale Bragg gratings

    DEFF Research Database (Denmark)

    Reck, Kasper; Almind, Ninia Sejersen; Mar, Mikkel Dysseholm

    2009-01-01

    We present modeling and design of an all-optical MEMS Bragg grating (half-pitch of 125 nm) strain sensor for single-fiber distributed sensing. Low optical loss and the use of frequency modulation rather than amplitude modulation, makes this sensor better suited for distributed systems than...... mechanical amplification can be obtained if using an angled double beam micrometer scale MEMS structure, compared to conventional fiber Bragg grating sensors. An optimized design and fabrication process is presented....

  10. Laser stabilization with a frequency-to-voltage chip for narrow-line laser cooling.

    Science.gov (United States)

    McFerran, J J

    2018-04-01

    We use integrated circuit-based frequency-to-voltage conversion of a frequency comb beat signal as the means for laser frequency stabilization that is suitable for narrow-line laser cooling. The method is compared to an atomic beam lock where the laser frequency instability for the new scheme shows an improvement of 2 orders of magnitude at sub-1 s and grants a lock-capture range that is approximately 30 times greater. We employ the locking method on a 1111.6 nm laser that is frequency doubled and used in a dual-wavelength magneto-optical trap for Yb171 atoms, producing atomic cloud temperatures of ∼20  μK.

  11. Bandgap Engineering of 1300 nm Quantum Dots/Quantum Well Nanostructures Based Devices

    KAUST Repository

    Alhashim, Hala H.

    2016-05-29

    The main objectives of this thesis are to develop viable process and/or device technologies for bandgap tuning of 1300-nm InGaAs/GaAs quantum-dot (QD) laser structures, and broad linewidth 1300-nm InGaAsP/InP quantum well (QW) superluminescent diode structures. The high performance bandgap-engineered QD laser structures were achieved by employing quantum-dot intermixing (QDI) based on impurity free vacancy diffusion (IFVD) technique for eventual seamless active-passive integration, and bandgap-tuned lasers. QDI using various dielectric-capping materials, such as HfO2, SrTiO3, TiO2, Al2O3 and ZnO, etc, were experimented in which the resultant emission wavelength can be blueshifted to ∼ 1100 nm ─ 1200 nm range depending on process conditions. The significant results extracted from the PL characterization were used to perform an extensive laser characterization. The InAs/GaAs quantum-dot lasers with QDs transition energies were blueshifted by ~185 nm, and lasing around ~1070 – 1190 nm was achieved. Furthermore, from the spectral analysis, a simultaneous five-state lasing in the InAs/InGaAs intermixed QD laser was experimentally demonstrated for the first time in the very important wavelength range from 1030 to 1125 nm. The QDI methodology enabled the facile formation of a plethora of devices with various emission wavelengths suitable for a wide range of applications in the infrared. In addition, the wavelength range achieved is also applicable for coherent light generation in the green – yellow – orange visible wavelength band via frequency doubling, which is a cost-effective way of producing compact devices for pico-projectors, semiconductor laser based solid state lighting, etc. [1, 2] In QW-based superluminescent diode, the problem statement lies on achieving a flat-top and ultra-wide emission bandwidth. The approach was to design an inhomogeneous active region with a comparable simultaneous emission from different transition states in the QW stacks, in

  12. 16.7 W 885 nm diode-side-pumped actively Q-switched Nd:YAG/YVO4 intracavity Raman laser at 1176 nm

    Science.gov (United States)

    Jiang, Pengbo; Zhang, Guizhong; Liu, Jian; Ding, Xin; Sheng, Quan; Yu, Xuanyi; Sun, Bing; Shi, Rui; Wu, Liang; Wang, Rui; Yao, Jianquan

    2017-11-01

    We proposed and experimentally demonstrated the generation of high-power 1176 nm Stokes wave by frequency shifting of a 885 nm diode-side-pumped Nd:YAG laser using a YVO4 crystal in a Z-shaped cavity configuration. Employing the 885 nm diode-side-pumped scheme and the Z-shaped cavity, for the first time to our knowledge, we realized the thermal management effectively, achieving excellent 1176 nm Stokes wave consequently. With an incident pump power of ~190.0 W, a maximum average output power of 16.7 W was obtained at the pulse repetition frequency of 10 kHz. The pulse duration and spectrum linewidth of the Stokes wave at the maximum output power were 20.3 ns and ~0.08 nm, respectively.

  13. Double ambidexterity

    DEFF Research Database (Denmark)

    Kaulio, Matti; Thorén, Kent; Rohrbeck, René

    2017-01-01

    We leverage the business model innovation and ambidexterity literature to investigate a contradictory case, the Swedish-Finnish Telecom operator TeliaSonera. Despite being challenged by three major disruptions, the company not only still exists but also enjoys remarkably good financial performance...... this behaviour as double ambidexterity. We use an in-depth case study to conceptualize double ambidexterity and discuss its impact on the business's survival and enduring success........ Building on extant archival data and interviews, we carefully identify and map 26 organizational responses during 1992–2016. We find that the firm has overcome three critical phases by experimenting and pioneering with portfolios of business models and/or technological innovations. We describe...

  14. Double Chooz

    Energy Technology Data Exchange (ETDEWEB)

    Buck, Christian [Max-Planck-Institut fuer Kernphysik, Saupfercheckweg 1, D-69117 Heidelberg (Germany)

    2006-05-15

    The goal of the Double Chooz reactor neutrino experiment is to search for the neutrino mixing parameter {theta}{sub 13}. Double Chooz will use two identical detectors at 150 m and 1.05 km distance from the reactor cores. The near detector is used to monitor the reactor {nu}-bar {sub e} flux while the second is dedicated to the search for a deviation from the expected (1/distance){sup 2} behavior. This two detector concept will allow a relative normalization systematic error of ca. 0.6 %. The expected sensitivity for sin{sup 2}2{theta}{sub 13} is then in the range 0.02 - 0.03 after three years of data taking. The antineutrinos will be detected in a liquid scintillator through the capture on protons followed by a gamma cascade, produced by the neutron capture on Gd.

  15. Long Term Ultrastable Laser System at 780 nm for Atomic Clocks, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Gener8 and AOSense team together to propose a novel new architecture for a low-phase noise, single-frequency electronically tunable laser at 780 nm. This laser...

  16. Double Dirac cones in phononic crystals

    KAUST Repository

    Li, Yan

    2014-07-07

    A double Dirac cone is realized at the center of the Brillouin zone of a two-dimensional phononic crystal (PC) consisting of a triangular array of core-shell-structure cylinders in water. The double Dirac cone is induced by the accidental degeneracy of two double-degenerate Bloch states. Using a perturbation method, we demonstrate that the double Dirac cone is composed of two identical and overlapping Dirac cones whose linear slopes can also be accurately predicted from the method. Because the double Dirac cone occurs at a relatively low frequency, a slab of the PC can be mapped onto a slab of zero refractive index material by using a standard retrieval method. Total transmission without phase change and energy tunneling at the double Dirac point frequency are unambiguously demonstrated by two examples. Potential applications can be expected in diverse fields such as acoustic wave manipulations and energy flow control.

  17. Progress on high-power 808nm VCSELs and applications

    Science.gov (United States)

    Zhou, Delai; Seurin, Jean-Francois; Xu, Guoyang; Van Leeuwen, Robert; Miglo, Alexander; Wang, Qing; Kovsh, Alexey; Ghosh, Chuni

    2017-02-01

    High power 808nm semiconductor lasers are widely used for pumping neodymium-doped yttrium aluminum garnet (Nd:YAG) crystal to produce high-brightness lasing at 1064nm. In addition, there are growing interest to use such high power 808nm lasers in the field of automotive infra-red (IR) illumination and medical aesthetic treatment. Vertical-cavity surface-emitting lasers (VCSELs) have emerged as a promising candidate and attracted increased interests for those applications, due to their combined advantages of high efficiency, low diverging circular beam, narrow emission spectrum with reduced temperature sensitivity, low-cost manufacturability, simpler coupling optics, and increased reliability, especially at high temperatures. They can emit very high power with very high power density as they can be conveniently configured into large two-dimensional arrays and modules of arrays. We report recent development on such high-power, high-efficiency 808nm VCSELs with industrial leading 55% power conversion efficiency (PCE). Top emitting VCSELs were grown by MOCVD and processed into single devices and 2D arrays using selective wet oxidation process and substrate removal technique for efficient current confinement and heat removal. Peak PCE of 51% and peak power of 800W were achieved from 5x5mm array, corresponding to peak power density of 4kW/cm2. Pumped with new generation of 2.3kW VCSEL module, Q-switched laser pulse energy at 1064nm reached 46.9mJ, more than doubled from previously reported results.

  18. High-power diode-end-pumped Tm:YLF slab laser delivering 189 W at 1890 nm

    CSIR Research Space (South Africa)

    Koen, W

    2010-09-01

    Full Text Available The authors present a high-power Tm:YLF slab laser double-end-pumped by two 300 W laser diode stacks. The resonator was designed such that the laser emitted at 1890 nm instead of the conventional operating wavelength of 1912 nm. At full incident...

  19. Enhanced double patterning decomposition using lines encoding

    Directory of Open Access Journals (Sweden)

    Khaled M. Soradi

    2016-09-01

    Full Text Available Double patterning photolithography (DPL is considered one of the best solutions used for enabling 32 nm/22 nm technology. In this paper, we propose a new technique for double patterning post decomposition conflict resolution. The algorithm is based on lines positions encoding followed by code pattern matching. Experimental results show that the usage of encoded patterns decreases the time needed for pattern matching and increases the matching accuracy. The overall manual problem solution time is reduced to about 1%.

  20. Microfabricated ion frequency standard

    Science.gov (United States)

    Schwindt, Peter; Biedermann, Grant; Blain, Matthew G.; Stick, Daniel L.; Serkland, Darwin K.; Olsson, III, Roy H.

    2010-12-28

    A microfabricated ion frequency standard (i.e. an ion clock) is disclosed with a permanently-sealed vacuum package containing a source of ytterbium (Yb) ions and an octupole ion trap. The source of Yb ions is a micro-hotplate which generates Yb atoms which are then ionized by a ultraviolet light-emitting diode or a field-emission electron source. The octupole ion trap, which confines the Yb ions, is formed from suspended electrodes on a number of stacked-up substrates. A microwave source excites a ground-state transition frequency of the Yb ions, with a frequency-doubled vertical-external-cavity laser (VECSEL) then exciting the Yb ions up to an excited state to produce fluorescent light which is used to tune the microwave source to the ground-state transition frequency, with the microwave source providing a precise frequency output for the ion clock.

  1. Laser hypersensitisation using 266nm light

    DEFF Research Database (Denmark)

    Sørensen, Henrik Rokkjær; Canning, J.; Kristensen, Martin

    2005-01-01

    UV hypersensitisation using CW 266 nm light on hydrogenated Ge-doped fibre is reported. The optimum sensitisation fluence is found to be in the range of 5 to 10 kJ/cm2, coinciding with previous results obtained using 355 nm light, indicating the same end-process used in the photochemical reaction...

  2. Capillary Condensation in 8 nm Deep Channels.

    Science.gov (United States)

    Zhong, Junjie; Riordon, Jason; Zandavi, Seyed Hadi; Xu, Yi; Persad, Aaron H; Mostowfi, Farshid; Sinton, David

    2018-02-01

    Condensation on the nanoscale is essential to understand many natural and synthetic systems relevant to water, air, and energy. Despite its importance, the underlying physics of condensation initiation and propagation remain largely unknown at sub-10 nm, mainly due to the challenges of controlling and probing such small systems. Here we study the condensation of n-propane down to 8 nm confinement in a nanofluidic system, distinct from previous studies at ∼100 nm. The condensation initiates significantly earlier in the 8 nm channels, and it initiates from the entrance, in contrast to channels just 10 times larger. The condensate propagation is observed to be governed by two liquid-vapor interfaces with an interplay between film and bridging effects. We model the experimental results using classical theories and find good agreement, demonstrating that this 8 nm nonpolar fluid system can be treated as a continuum from a thermodynamic perspective, despite having only 10-20 molecular layers.

  3. High power all-solid-state fourth harmonic generation of 266 nm at the pulse repetition rate of 100 kHz

    International Nuclear Information System (INIS)

    Liu, Q; Yan, X P; Fu, X; Gong, M; Wang, D S

    2009-01-01

    14.8 W UV laser at 266 nm was reported with the extra cavity frequency quartered configuration. The fundamental frequency IR source is a high-power high-beam-quality acoustic-optic Q-switched Nd:YVO 4 master-oscillator-power-amplifier laser. The type-I phase-matched LBO and type-I phase-matched BBO crystals were used as the extra-cavity frequency doubled and quartered crystal respectively. 14.8 W UV laser of 266 nm was obtained at the pulse repetition rate of 100 kHz with the conversion efficiency of 18.3% from green to UV, and the pulse duration of the UV laser was 10 ns corresponding to the pulse peak power of 14.8 kW. At 150 kHz, 11.5 W power output was obtained. The highest peak power of 21 kW was also achieved at 80 kHz with the average output power of 14.5 W

  4. Solid tissue simulating phantoms having absorption at 970 nm for diffuse optics

    Science.gov (United States)

    Kennedy, Gordon T.; Lentsch, Griffin R.; Trieu, Brandon; Ponticorvo, Adrien; Saager, Rolf B.; Durkin, Anthony J.

    2017-07-01

    Tissue simulating phantoms can provide a valuable platform for quantitative evaluation of the performance of diffuse optical devices. While solid phantoms have been developed for applications related to characterizing exogenous fluorescence and intrinsic chromophores such as hemoglobin and melanin, we report the development of a poly(dimethylsiloxane) (PDMS) tissue phantom that mimics the spectral characteristics of tissue water. We have developed these phantoms to mimic different water fractions in tissue, with the purpose of testing new devices within the context of clinical applications such as burn wound triage. Compared to liquid phantoms, cured PDMS phantoms are easier to transport and use and have a longer usable life than gelatin-based phantoms. As silicone is hydrophobic, 9606 dye was used to mimic the optical absorption feature of water in the vicinity of 970 nm. Scattering properties are determined by adding titanium dioxide, which yields a wavelength-dependent scattering coefficient similar to that observed in tissue in the near-infrared. Phantom properties were characterized and validated using the techniques of inverse adding-doubling and spatial frequency domain imaging. Results presented here demonstrate that we can fabricate solid phantoms that can be used to simulate different water fractions.

  5. Versatile, high-power 460 nm laser system for Rydberg excitation of ultracold potassium.

    Science.gov (United States)

    Arias, Alda; Helmrich, Stephan; Schweiger, Christoph; Ardizzone, Lynton; Lochead, Graham; Whitlock, Shannon

    2017-06-26

    We present a versatile laser system which provides more than 1.5 W of narrowband light, tunable in the range from 455-463 nm. It consists of a commercial titanium-sapphire laser which is frequency doubled using resonant cavity second harmonic generation and stabilized to an external reference cavity. We demonstrate a wide wavelength tuning range combined with a narrow linewidth and low intensity noise. This laser system is ideally suited for atomic physics experiments such as two-photon excitation of Rydberg states of potassium atoms with principal quantum numbers n > 18. To demonstrate this we perform two-photon spectroscopy on ultracold potassium gases in which we observe an electromagnetically induced transparency resonance corresponding to the 35s 1/2 state and verify the long-term stability of the laser system. Additionally, by performing spectroscopy in a magneto-optical trap we observe strong loss features corresponding to the excitation of s, p, d and higher-l states accessible due to a small electric field.

  6. Solid tissue simulating phantoms having absorption at 970 nm for diffuse optics.

    Science.gov (United States)

    Kennedy, Gordon T; Lentsch, Griffin R; Trieu, Brandon; Ponticorvo, Adrien; Saager, Rolf B; Durkin, Anthony J

    2017-07-01

    Tissue simulating phantoms can provide a valuable platform for quantitative evaluation of the performance of diffuse optical devices. While solid phantoms have been developed for applications related to characterizing exogenous fluorescence and intrinsic chromophores such as hemoglobin and melanin, we report the development of a poly(dimethylsiloxane) (PDMS) tissue phantom that mimics the spectral characteristics of tissue water. We have developed these phantoms to mimic different water fractions in tissue, with the purpose of testing new devices within the context of clinical applications such as burn wound triage. Compared to liquid phantoms, cured PDMS phantoms are easier to transport and use and have a longer usable life than gelatin-based phantoms. As silicone is hydrophobic, 9606 dye was used to mimic the optical absorption feature of water in the vicinity of 970 nm. Scattering properties are determined by adding titanium dioxide, which yields a wavelength-dependent scattering coefficient similar to that observed in tissue in the near-infrared. Phantom properties were characterized and validated using the techniques of inverse adding-doubling and spatial frequency domain imaging. Results presented here demonstrate that we can fabricate solid phantoms that can be used to simulate different water fractions

  7. Gold Nanoparticles of Diameter 13 nm Induce Apoptosis in Rabbit Articular Chondrocytes

    Science.gov (United States)

    Huang, Hao; Quan, Ying-yao; Wang, Xiao-ping; Chen, Tong-sheng

    2016-05-01

    Gold nanoparticles (AuNPs) have been widely used in biomedical science including antiarthritic agents, drug loading, and photothermal therapy. In this report, we studied the effects of AuNPs with diameters of 3, 13, and 45 nm, respectively, on rabbit articular chondrocytes. AuNPs were capped with citrate and their diameter and zeta potential were measured by dynamic light scattering (DLS). Cell viability was evaluated by Cell Counting Kit-8 (CCK-8) assay after the rabbit articular chondrocytes were pre-incubated with 3, 13, and 45 nm AuNPs, respectively, for 24 h. Flow cytometry (FCM) analysis with annexin V/propidium iodide (PI) double staining and fluorescence imaging with Hoechst 33258 staining were used to determine the fashion of AuNPs-induced chondrocyte death. Further, 13 nm AuNPs (2 nM) significantly induced chondrocyte death accompanying apoptotic characteristics including mitochondrial damage, externalization of phosphatidylserine and nuclear concentration. However, 3 nm AuNPs (2 nM) and 45 nm (0.02 nM) AuNPs did not induce cytotoxicity in chondrocytes. Although 13 nm AuNPs (2 nM) increased the intracellular reactive oxygen species (ROS) level, pretreatment with Nacetyl cysteine (NAC), a ROS scavenger, did not prevent the cytotoxicity induced by 13 nm AuNPs, indicating that 13 nm AuNPs (2 nM) induced ROS-independent apoptosis in chondrocytes. These results demonstrate the size-dependent cytotoxicity of AuNPs in chondrocytes, which must be seriously considered when using AuNPs for treatment of osteoarthritis (OA).

  8. Gallup, NM, CARE Grant Success Story

    Science.gov (United States)

    A CARE Grant, Level II award, was made to Gallup, NM to focus on cleaning up the waste stream, reuse and recycling of materials, and reclaiming land for these purposes through outreach, education and organization.

  9. Design of an 1800 nm Raman Amplifier

    DEFF Research Database (Denmark)

    Svane, Ask Sebastian; Rottwitt, Karsten

    , also extended band amplifiers are required. As a solution to the latter challenge, Raman amplifiers are suggested as promising candidates. The main hurdle when designing a long wavelength Raman amplifier is the increased intrinsic fiber attenuation which as a consequence leads to an increase...... in the pump power requirement and deteriorated noise properties. Here we demonstrate a Raman amplifier designed for signal wavelengths around 1800 nm. The amplification fiber is an OFS PM Raman fiber, and is pumped by a Raman fiber laser emitting at 1680 nm [4]. The amplifier was pumped co......-polarized and backward, with respect to the singal. In Fig. 2 a measured Raman on/off gain exceeding 9 dB for 285 mW of injected pump power is obtained in a 4.35 km long fiber. A broadband supercontinuum source was used as a signal from 1700 nm to 1900 nm....

  10. Cascaded quadratic soliton compression at 800 nm

    DEFF Research Database (Denmark)

    Bache, Morten; Bang, Ole; Moses, Jeffrey

    2007-01-01

    We study soliton compression in quadratic nonlinear materials at 800 nm, where group-velocity mismatch dominates. We develop a nonlocal theory showing that efficient compression depends strongly on characteristic nonlocal time scales related to pulse dispersion.......We study soliton compression in quadratic nonlinear materials at 800 nm, where group-velocity mismatch dominates. We develop a nonlocal theory showing that efficient compression depends strongly on characteristic nonlocal time scales related to pulse dispersion....

  11. PM Raman fiber laser at 1679 nm

    DEFF Research Database (Denmark)

    Svane, Ask Sebastian; Rottwitt, Karsten

    2012-01-01

    We demonstrate a PM Raman fiber laser emitting light at 1679 nm. The laser has an slope efficiency of 67 % and an output power of more than 275mWwith a 27 pm linewidth.......We demonstrate a PM Raman fiber laser emitting light at 1679 nm. The laser has an slope efficiency of 67 % and an output power of more than 275mWwith a 27 pm linewidth....

  12. Doubling Syndemics

    Science.gov (United States)

    2017-01-01

    Abstract This study investigates health concerns and access to health services for Roma from Romania who live in homelessness in Copenhagen, Denmark. They collect refundable bottles and call themselves “badocari,” which in Romanian refers to “people who work with bottles.” Homeless Roma in Denmark have not previously been studied through ethnographic research. The study stresses the importance of a syndemic approach towards understanding badocari health concerns. Syndemics is understood as co-occurring diseases, which unfold within contexts of social injustice. The case of the badocari is argued to be a case of “doubling syndemics” since the co-occurring diseases are further multiplied and enhanced by an ongoing mobility between dual contexts of precarious livelihoods in Romania and Denmark, respectively. The study complements the approach to syndemics with a perspective on human rights. It sheds light on the limited possibilities that exist for addressing health concerns of the badocari, both in Romania and in Denmark, and argues that the universal human right to health is not realized in the everyday lives of destitute EU migrants such as the badocari. Rather, they experience lack of access to adequate medical treatment and follow-up care, both as citizens of a member state and as co-citizens of the European Union. PMID:29302164

  13. Flare evaluation for 32-nm half pitch using SFET

    Science.gov (United States)

    Aoyama, Hajime; Tanaka, Yuusuke; Kamo, Takashi; Iriki, Nobuyuki; Arisawa, Yukiyasu; Tanaka, Toshihiko

    2008-03-01

    Flare degrades critical-dimension (CD) control in EUVL, a promising technology for the 32-nm half-pitch node. To deal with flare, high-quality projection optics in the exposure tool and flare variation compensation (FVC) technology with proper mask resizing are needed. Selete has installed a small-field exposure tool (SFET) with the goal of assessing resist performance. Due to the high-quality optics, the SFET allowed us to determine the required flare specification to be 6.1% or 6.6%, as calculated from the residual part of the low- or middle-frequency region, respectively. The flare level was confirmed through experimental results and from calculations using the power spectral density (PSD) obtained from the mirror roughness by the disappearing-resist method. The lithographic performance was evaluated using 32-nm-halfpitch patterns in a new resist. The resist characteristics can be explained by modeling blur as a Gaussian function with a σ of 8.8 nm and using a very accurate CD variation (area or not, there was no difference in CD as a function of distance up to a distance of 20 µm. In addition, CD degradation was observed at distances not far (area. In a 60-nm neighborhood of the open area, an 8-nm variation in CD appeared up to the distance at which the CD leveled off. When the influences of resist blur and flare on patterns was taken into account in the calculation, it was found that aerial simulations based on a rigorous 3D model of a mask structure matched the experimental results. These results yield the appropriate mask resizing and the range in which flare has an influence, which is needed for FVC. This research was supported in part by NEDO.

  14. Three Year Aging of Prototype Flight Laser at 10 Khz and 1 Ns Pulses with External Frequency Doubler for the Icesat-2 Mission

    Science.gov (United States)

    Konoplev, Oleg A.; Chiragh, Furqan L.; Vasilyev, Aleksey A.; Edwards, Ryan; Stephen, Mark A.; Troupaki, Elisavet; Yu, Anthony W.; Krainak, Michael A.; Sawruk, Nick; Hovis, Floyd; hide

    2016-01-01

    We present the results of three year life-aging of a specially designed prototype flight source laser operating at 1064 nm, 10 kHz, 1ns, 15W average power and external frequency doubler. The Fibertek-designed, slightly pressurized air, enclosed-container source laser operated at 1064 nm in active Q-switching mode. The external frequency doubler was set in a clean room at a normal air pressure. The goal of the experiment was to measure degradation modes at 1064 and 532 nm discreetly. The external frequency doubler consisted of a Lithium triborate, LiB3O5, crystal operated at non-critical phase-matching. Due to 1064 nm diagnostic needs, the amount of fundamental frequency power available for doubling was 13.7W. The power generated at 532 nm was between 8.5W and 10W, depending on the level of stress and degradation. The life-aging consisted of double stress-step operation for doubler crystal, at 0.35 J/cm2 for almost 1 year, corresponding to normal conditions, and then at 0.93 J/cm2 for the rest of the experiment, corresponding to accelerated testing. We observed no degradation at the first step and linear degradation at the second step. The linear degradation at the second stress-step was related to doubler crystal output surface changes and linked to laser-assisted contamination. We discuss degradation model and estimate the expected lifetime for the flight laser at 532 nm. This work was done within the laser testing for NASA's Ice, Cloud, and land Elevation Satellite-2 (ICESat-2) LIDAR at Goddard Space Flight Center in Greenbelt, MD with the goal of 1 trillion shots lifetime.

  15. Three Three-Year Aging of Prototype Flight Laser at 10 kHz and 1 ns Pulses With External Frequency Doubler for ICESat-2 Mission

    Science.gov (United States)

    Konoplev, Oleg A.; Chiragh, Furqan L.; Vasilyev, Aleksey A.; Edwards, Ryan; Stephen, Mark A.; Troupaki, Elisavet; Yu, Anthony W.; Krainak, Michael A.; Sawruk, Nick; Hovis, Floyd; hide

    2016-01-01

    We present the results of three year life-aging of a specially designed prototype flight source laser operating at 1064 nm, 10 kHz, 1ns, 15W average power and external frequency doubler. The Fibertek-designed, slightly pressurized air, enclosed-container source laser operated at 1064 nm in active Q-switching mode. The external frequency doubler was set in a clean room at a normal air pressure. The goal of the experiment was to measure degradation modes at 1064 and 532 nm discreetly. The external frequency doubler consisted of a Lithium triborate, LiB3O5, crystal operated at non-critical phase-matching. Due to 1064 nm diagnostic needs, the amount of fundamental frequency power available for doubling was 13.7W. The power generated at 532 nm was between 8.5W and 10W, depending on the level of stress and degradation. The life-aging consisted of double stress-step operation for doubler crystal, at 0.35 Jcm2 for almost 1 year, corresponding to normal conditions, and then at 0.93 Jcm2 for the rest of the experiment, corresponding to accelerated testing. We observed no degradation at the first step and linear degradation at the second step. The linear degradation at the second stress-step was related to doubler crystal output surface changes and linked to laser-assisted contamination. We discuss degradation model and estimate the expected lifetime for the flight laser at 532 nm. This work was done within the laser testing for NASAs Ice, Cloud, and land Elevation Satellite-2 (ICESat-2) LIDAR at Goddard Space Flight Center in Greenbelt, MD with the goal of 1 trillion shots lifetime.

  16. Double inflation

    International Nuclear Information System (INIS)

    Silk, J.; Turner, M.S.

    1986-04-01

    The Zel'dovich spectrum of adiabatic density perturbations is a generic prediction of inflation. There is increasing evidence that when the spectrum is normalized by observational data on small scales, there is not enough power on large scales to account for the observed large-scale structure in the Universe. Decoupling the spectrum on large and small scales could solve this problem. As a means of decoupling the large and small scales we propose double inflation (i.e., two episodes of inflation). In this scenario the spectrum on large scales is determined by the first episode of inflation and those on small scales by a second episode of inflation. We present three models for such a scenario. By nearly saturating the large angular-scale cosmic microwave anisotropy bound, we can easily account for the observed large-scale structure. We take the perturbations on small scales to be very large, deltarho/rho approx. = 0.1 to 0.01, which results in the production of primordial black holes (PBHs), early formation of structure, reionization of the Universe, and a rich array of astrophysical events. The Ω-problem is also addressed by our scenario. Allowing the density perturbations produced by the second episode of inflation to be large also lessens the fine-tuning required in the scalar potential and makes reheating much easier. We briefly speculate on the possibility that the second episode of inflation proceeds through the nucleation of bubbles, which today manifest themselves as empty bubbles whose surfaces are covered with galaxies. 37 refs., 1 fig

  17. Radiation Failures in Intel 14nm Microprocessors

    Science.gov (United States)

    Bossev, Dobrin P.; Duncan, Adam R.; Gadlage, Matthew J.; Roach, Austin H.; Kay, Matthew J.; Szabo, Carl; Berger, Tammy J.; York, Darin A.; Williams, Aaron; LaBel, K.; hide

    2016-01-01

    In this study the 14 nm Intel Broadwell 5th generation core series 5005U-i3 and 5200U-i5 was mounted on Dell Inspiron laptops, MSI Cubi and Gigabyte Brix barebones and tested with Windows 8 and CentOS7 at idle. Heavy-ion-induced hard- and catastrophic failures do not appear to be related to the Intel 14nm Tri-Gate FinFET process. They originate from a small (9 m 140 m) area on the 32nm planar PCH die (not the CPU) as initially speculated. The hard failures seem to be due to a SEE but the exact physical mechanism has yet to be identified. Some possibilities include latch-ups, charge ion trapping or implantation, ion channels, or a combination of those (in biased conditions). The mechanism of the catastrophic failures seems related to the presence of electric power (1.05V core voltage). The 1064 nm laser mimics ionization radiation and induces soft- and hard failures as a direct result of electron-hole pair production, not heat. The 14nm FinFET processes continue to look promising for space radiation environments.

  18. Photomask development for 90-nm technology

    Science.gov (United States)

    Zhang, Yuan; Cottle, Rand; Mackay, Scott; Xiao, Guangming; Unruh, James; Progler, Christopher J.

    2005-01-01

    To accelerate the time-to-market of advanced photomasks, Photronics launched its 90nm program in spring 2003. The program included three learning cycles and a technology transfer phase. Both 90nm test masks and product masks from leading integrated device manufacturers (IDMs) and foundries were exercised through the cycles. Stringent success criteria were set based on a survey of leading customers" requirements and the International Technology Roadmap for Semiconductors (ITRS). Hundreds of binary masks, embedded attenuated phase shift masks (EAPSMs), and alternating aperture phase shift masks (AAPSMs) were produced throughout the program. All targets were exceeded. This paper describes program success criteria, complexity of customer requirements, 90nm test vehicle design, and efforts on improving critical dimension (CD) uniformity and registration. Results in positive and negative chemically amplified resist (CAR) and tunable etching for AAPSM are shown. Details on AAPSM undercut optimization, intensity and CD imbalance are reported.

  19. Nanoprocessing of metastable nm-period multilayers

    Science.gov (United States)

    Gorbunov, A. A.; Richter, J.; Pompe, W.

    Nanometer-period nickel-carbon multilayers were used as a medium for the fabrication of nanostructures by gap voltage manipulations in a scanning tunneling microscope. The written metallic structures were stable over at least several weeks. No traces of tip material were found in the processed areas. Two well-distinguished hillock-like nanostructure types were observed depending on the tip-sample separation, polarity and interaction time. Relatively slow local annealing under positive sample potential without a direct tip-sample contact resulted in the formation of nanostructures about 20 nm wide and a few nm high. Rapid melting followed by metal melt extrusion was observed if the tip contacted the sample during the nanostructure formation. These metal-like structures were tens of nm high and had a good electronic contrast to the initial carbon-coated surface. The formation of nanostructures was strongly dependent on the tip condition. Possible mechanisms of nanostructure formation are discussed.

  20. Design of an 1800nm Raman amplifier

    DEFF Research Database (Denmark)

    Svane, Ask Sebastian; Rottwitt, Karsten

    2013-01-01

    We present the experimental results for a Raman amplifier that operates at 1810 nm and is pumped by a Raman fiber laser at 1680 nm. Both the pump laser and the Raman amplifier is polarization maintaining. A challenge when scaling Raman amplifiers to longer wavelengths is the increase...... in transmission loss, but also the reduction in the Raman gain coefficient as the amplifier wavelength is increased. Both polarization components of the Raman gain is characterized, initially for linearly co-polarized signal and pump, subsequently linearly polarized orthogonal signal and pump. The noise...... performance of the amplifier is also investigated for both configurations. Our results show an on/off gain exceeding 20 dB at 1810 nm for which the obtained effective noise figure is below 3 dB....

  1. Water line positions in the 782–840 nm region

    International Nuclear Information System (INIS)

    Hu, S.-M.; Chen, B.; Tan, Y.; Wang, J.; Cheng, C.-F.; Liu, A.-W.

    2015-01-01

    A set of water transitions in the 782–840 nm region, including 38 H 2 16 O lines, 12 HD 16 O lines, and 30 D 2 16 O lines, were recorded with a cavity ring-down spectrometer calibrated using precise atomic lines. Absolute frequencies of the lines were determined with an accuracy of about 5 MHz. Systematic shifts were found in the line positions given in the HITRAN database and the upper energy levels given in recent MARVEL studies. - Highlights: • Cavity ring-down spectra of H 2 16 O, HD 16 O, and D 2 16 O lines in the 782–840 nm region were measured. • Absolute line positions of 80 water lines were determined with an accuracy of about 5 MHz. • The H 2 16 O positions given in HITRAN have a systematic shift of 0.001 cm −1 in the 796–840 nm region. • MARVEL D 2 16 O energies have a systematic deviation of about −0.008 cm −1

  2. Visible ns-pulse laser oscillation in Pr-doped double-clad structured waterproof fluoride glass fibre with SESAM

    Directory of Open Access Journals (Sweden)

    Shota Kajikawa

    2017-06-01

    Full Text Available A visible Q-switched pulse train at 639 nm was successfully generated in a Pr-doped double-clad structured waterproof fluoride glass fibre with a semiconductor saturable absorber mirror. The slope efficiency was calculated as 36.3%. The pulse duration and the radio frequency were measured as 270 ns and 107 kHz at 596 mW of absorbed power, respectively. The pulse energy and the pulse peak power were calculated as 1.32 μJ and 4.87 W, respectively.

  3. Liquid Carbon Reflectivity at 19 nm

    Directory of Open Access Journals (Sweden)

    Riccardo Mincigrucci

    2015-01-01

    Full Text Available We hereby report on a pump-probe reflectivity experiment conducted on amorphous carbon, using a 780 nm laser as a pump and a 19 nm FEL emission as probe. Measurements were performed at 50 degrees with respect to the surface normal to have an un-pumped reflectivity higher than 0.5%. A sub-10 fs time synchronization error could be obtained exploiting the nearly jitter-free capabilities of FERMI. EUV FEL-based experiments open the way to study the behaviour of a liquid carbon phase being unaffected by plasma screening.

  4. Double hard scattering without double counting

    Science.gov (United States)

    Diehl, Markus; Gaunt, Jonathan R.; Schönwald, Kay

    2017-06-01

    Double parton scattering in proton-proton collisions includes kinematic regions in which two partons inside a proton originate from the perturbative splitting of a single parton. This leads to a double counting problem between single and double hard scattering. We present a solution to this problem, which allows for the definition of double parton distributions as operator matrix elements in a proton, and which can be used at higher orders in perturbation theory. We show how the evaluation of double hard scattering in this framework can provide a rough estimate for the size of the higher-order contributions to single hard scattering that are affected by double counting. In a numeric study, we identify situations in which these higher-order contributions must be explicitly calculated and included if one wants to attain an accuracy at which double hard scattering becomes relevant, and other situations where such contributions may be neglected.

  5. Double hard scattering without double counting

    Energy Technology Data Exchange (ETDEWEB)

    Diehl, Markus [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Gaunt, Jonathan R. [VU Univ. Amsterdam (Netherlands). NIKHEF Theory Group; Schoenwald, Kay [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany)

    2017-02-15

    Double parton scattering in proton-proton collisions includes kinematic regions in which two partons inside a proton originate from the perturbative splitting of a single parton. This leads to a double counting problem between single and double hard scattering. We present a solution to this problem, which allows for the definition of double parton distributions as operator matrix elements in a proton, and which can be used at higher orders in perturbation theory. We show how the evaluation of double hard scattering in this framework can provide a rough estimate for the size of the higher-order contributions to single hard scattering that are affected by double counting. In a numeric study, we identify situations in which these higher-order contributions must be explicitly calculated and included if one wants to attain an accuracy at which double hard scattering becomes relevant, and other situations where such contributions may be neglected.

  6. Reduced nonlinearities in 100-nm high SOI waveguides

    Science.gov (United States)

    Lacava, C.; Marchetti, R.; Vitali, V.; Cristiani, I.; Giuliani, G.; Fournier, M.; Bernabe, S.; Minzioni, P.

    2016-03-01

    Here we show the results of an experimental analysis dedicated to investigate the impact of optical non linear effects, such as two-photon absorption (TPA), free-carrier absorption (FCA) and free-carrier dispersion (FCD), on the performance of integrated micro-resonator based filters for application in WDM telecommunication systems. The filters were fabricated using SOI (Silicon-on-Insulator) technology by CEA-Leti, in the frame of the FP7 Fabulous Project, which aims to develop low-cost and high-performance integrated optical devices to be used in new generation passive optical- networks (NG-PON2). Different designs were tested, including both ring-based structures and racetrack-based structures, with single-, double- or triple- resonator configuration, and using different waveguide cross-sections (from 500 x 200 nm to 825 x 100 nm). Measurements were carried out using an external cavity tunable laser source operating in the extended telecom bandwidth, using both continuous wave signals and 10 Gbit/s modulated signals. Results show that the use 100-nm high waveguide allows reducing the impact of non-linear losses, with respect to the standard waveguides, thus increasing by more than 3 dB the maximum amount of optical power that can be injected into the devices before causing significant non-linear effects. Measurements with OOK-modulated signals at 10 Gbit/s showed that TPA and FCA don't affect the back-to-back BER of the signal, even when long pseudo-random-bit-sequences (PRBS) are used, as the FCD-induced filter-detuning increases filter losses but "prevents" excessive signal degradation.

  7. Dual-wavelength high-power diode laser system based on an external-cavity tapered amplifier with tunable frequency difference

    DEFF Research Database (Denmark)

    Chi, Mingjun; Jensen, Ole Bjarlin; Petersen, Paul Michael

    2012-01-01

    knowledge, this is the broadest tuning range of the frequency difference from a dual-wavelength diode laser system. The spectrum, output power, and beam quality of the diode laser system are characterized. The power stability of each wavelength is measured, and the power fluctuations of the two wavelengths......A dual-wavelength high-power semiconductor laser system based on a tapered amplifier with double-Littrow external cavity is demonstrated around 800 nm. The two wavelengths can be tuned individually, and the frequency difference of the two wavelengths is tunable from 0.5 to 10.0 THz. To our...

  8. 130-nm tunable grating-mirror VCSEL

    DEFF Research Database (Denmark)

    Chung, Il-Sug; Mørk, Jesper

    2014-01-01

    We have reported that a combination of the high-index-contrast grating (HCG) mirror as movable mirror and the extended cavity configuration with an antireflection layer can provide a tuning wavelength range of 100 nm for tunable VCSELs. Here, we report that using the air-coupled cavity configurat......We have reported that a combination of the high-index-contrast grating (HCG) mirror as movable mirror and the extended cavity configuration with an antireflection layer can provide a tuning wavelength range of 100 nm for tunable VCSELs. Here, we report that using the air-coupled cavity...... configuration instead of the extended cavity configuration can bring 130-nm tuning range around 1330-nm wavelength. The air-coupled cavity is known to reduce the quantum confinement factor in VCSELs, increasing threshold. In our air-coupled cavity HCG VCSEL case, the very short power penetration length...... in the HCG minimizes this reduction of the quantum confinement factor, not as significant as in the air-coupled cavity DBR VCSEL....

  9. 130-nm tunable grating-mirror VCSEL

    DEFF Research Database (Denmark)

    Chung, Il-Sug; Mørk, Jesper

    2014-01-01

    We have reported that a combination of the high-index-contrast grating (HCG) mirror as movable mirror and the extended cavity configuration with an antireflection layer can provide a tuning wavelength range of 100 nm for tunable VCSELs. Here, we report that using the air-coupled cavity...

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

    Science.gov (United States)

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

    2012-02-01

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

  11. Low loss silicon on insulator photonic crystal waveguides made by 193nm optical lithography.

    Science.gov (United States)

    Settle, Michael; Salib, Mike; Michaeli, Albert; Krauss, Thomas F

    2006-03-20

    We show the successful fabrication and operation of photonic crystal waveguides on SOI, with lower silicon dioxide cladding remaining, using 193 nm DUV lithography. We demonstrate that 193 nm lithography gives more process latitude, allowing a wider range of periods and hole diameters to be printed, as well as reducing the optical proximity effect to a minimum. The smallest period /hole size variation printed successfully was 280 nm and 150 nm, which is very promising for ambitious future designs. Lowest losses obtained were 14.2 +/- 2.0 dB/cm for a W1 waveguide in a 400 nm lattice with an r/a of 0.25 at a frequency of 0.257 a/lambda, which approaches the best losses reported for air-bridge type W1s.

  12. Results from a new 193nm die-to-database reticle inspection platform

    Science.gov (United States)

    Broadbent, William H.; Alles, David S.; Giusti, Michael T.; Kvamme, Damon F.; Shi, Rui-fang; Sousa, Weston L.; Walsh, Robert; Xiong, Yalin

    2010-05-01

    A new 193nm wavelength high resolution reticle defect inspection platform has been developed for both die-to-database and die-to-die inspection modes. In its initial configuration, this innovative platform has been designed to meet the reticle qualification requirements of the IC industry for the 22nm logic and 3xhp memory generations (and shrinks) with planned extensions to the next generation. The 22nm/3xhp IC generation includes advanced 193nm optical lithography using conventional RET, advanced computational lithography, and double patterning. Further, EUV pilot line lithography is beginning. This advanced 193nm inspection platform has world-class performance and the capability to meet these diverse needs in optical and EUV lithography. The architecture of the new 193nm inspection platform is described. Die-to-database inspection results are shown on a variety of reticles from industry sources; these reticles include standard programmed defect test reticles, as well as advanced optical and EUV product and product-like reticles. Results show high sensitivity and low false and nuisance detections on complex optical reticle designs and small feature size EUV reticles. A direct comparison with the existing industry standard 257nm wavelength inspection system shows measurable sensitivity improvement for small feature sizes

  13. Alveolar macrophage accumulation rates, for 28 nm and 250 nm PSL, are mediated by separate mechanisms

    Energy Technology Data Exchange (ETDEWEB)

    Moss, O R; Wong, V A, E-mail: moss@thehamner.or [Hamner Institutes for Health Sciences, Research Triangle Park, NC 27509-2137 (United States)

    2009-02-01

    When macrophages accumulate 28 nm and 250 nm diameter polystyrene latex (PSL) beads, the accumulation rates should reflect differences in molecular and cellular function. We used a confocal microscope to measure the accumulation rates of nanoparticles by F344-rat-alveolar macrophages (approx25,000 cells adhered to a 0.7 cm{sup 2} surface). Over the cells were layered 0.1 ml of media, and 0.1 ml of media-with-beads. Fresh cells were introduced for each exposure scenario. The maximum possible individual macrophage exposures were as follows: 8x10{sup 6}, 8x10{sup 5}, and 8x10{sup 4} 28 nm beads per macrophage; and 8x10{sup 4} and 1.12x10{sup 4} 250 nm beads per macrophage. Accumulation rates were estimated over 23 minutes. The increase in bead accumulation-rate matched changes in bead-availability: 7x increase for 250 nm beads; 100x increase for 28 nm beads; and 700x increase for all bead availabilities. The maximum sustained 28 nm bead accumulation rate was > 30,000 /min (for 5 min). Increases in bead accumulation could be explained by two mechanisms: bead-diffusion; and, for the macrophage, macropinocytosis. Also for the highest concentrations of 28 nm beads, we saw a colligative threshold - possibly due to beads masking the cell surface or obstructing cellular mechanisms.

  14. Alveolar macrophage accumulation rates, for 28 nm and 250 nm PSL, are mediated by separate mechanisms

    Science.gov (United States)

    Moss, O. R.; Wong, V. A.

    2009-02-01

    When macrophages accumulate 28 nm and 250 nm diameter polystyrene latex (PSL) beads, the accumulation rates should reflect differences in molecular and cellular function. We used a confocal microscope to measure the accumulation rates of nanoparticles by F344-rat-alveolar macrophages (~25,000 cells adhered to a 0.7 cm2 surface). Over the cells were layered 0.1 ml of media, and 0.1 ml of media-with-beads. Fresh cells were introduced for each exposure scenario. The maximum possible individual macrophage exposures were as follows: 8x106, 8x105, and 8x104 28 nm beads per macrophage; and 8x104 and 1.12x104 250 nm beads per macrophage. Accumulation rates were estimated over 23 minutes. The increase in bead accumulation-rate matched changes in bead-availability: 7x increase for 250 nm beads; 100x increase for 28 nm beads; and 700x increase for all bead availabilities. The maximum sustained 28 nm bead accumulation rate was > 30,000 /min (for 5 min). Increases in bead accumulation could be explained by two mechanisms: bead-diffusion; and, for the macrophage, macropinocytosis. Also for the highest concentrations of 28 nm beads, we saw a colligative threshold -- possibly due to beads masking the cell surface or obstructing cellular mechanisms.

  15. Repair of near-UV (365nm or 313 nm) induced DNA strand breaks

    International Nuclear Information System (INIS)

    Miguel, A.G.

    1981-01-01

    The action of near-UV (365 nm or 313 nm) radiation in cellular inactivaton (biological measurements) and induction and repair of breaks (physical measurements) is studied in repair proficient strain and in pol A, rec A and uvr A deficient strains of Escherichia coli K-12. (M.A.C.) [pt

  16. Two-photon-excited fluorescence spectroscopy of atomic fluorine at 170 nm

    Science.gov (United States)

    Herring, G. C.; Dyer, Mark J.; Jusinski, Leonard E.; Bischel, William K.

    1988-01-01

    Two-photon-excited fluorescence spectroscopy of atomic fluorine is reported. A doubled dye laser at 286-nm is Raman shifted in H2 to 170 nm (sixth anti-Stokes order) to excite ground-state 2P(0)J fluorine atoms to the 2D(0)J level. The fluorine atoms are detected by one of two methods: observing the fluorescence decay to the 2PJ level or observing F(+) production through the absorption of an additional photon by the excited atoms. Relative two-photon absorption cross sections to and the radiative lifetimes of the 2D(0)J states are measured.

  17. [The 308 nm excimer laser in dermatology].

    Science.gov (United States)

    Passeron, Thierry; Ortonne, Jean-Paul

    2005-02-26

    THE EFFICACY OF THE 308 NM EXCIMER LASER in the treatment of common psoriasis has been demonstrated. THE DOSES USED have progressively decreased, hence, limiting the adverse events that appear redhibitory with high doses. THE ADAPTATION OF THE DOSES not to the patients themselves but to each of the plaques treated should reduce the number of sessions and the cumulated close necessary to obtain clinical remission. THE 308 NM EXCIMER LASER is effective and tolerance is good in the treatment of vitiligo. It should be proposed for limited vitiligo and essentially of the "UV sensitive" areas, which have shown aesthetically correct percentage of repigmentation. THE PLACE AND INTEREST of its association with other treatments, notably with topical tacrolimus, remains to be defined. Although the results obtained in the treatment of vitiligo are promising, they have to be confirmed in larger cohorts and ensure the absence of median and long term side effects. This therefore limits its use in combined treatments in the context of controlled clinical traits. THE 30 NM EXCIMER LASER IS AN EFFECTIVE AND WELL TOLERATED TREATMENT in localised and non-nodular forms of mycosis fungoid (MF). Although the number of patients treated is limited, the clinical and histological cure observed demonstrates the interest of this new technique in the treatment of MF. These results must be confirmed in a greater number of patients. THE 308 NM EXCIMER LASER is an interesting therapeutic alternative in the treatment of plaques of alopecia areata, erosive oral lichen planus, post-surgical hypopigmentation, vergetures and localised forms of atopic dermatitis. Because of the sparcity of data and in the absence of long term follow-up, it must not be proposed in first intention.

  18. Theory of the double-edge molecular technique for Doppler lidar wind measurement.

    Science.gov (United States)

    Flesia, C; Korb, C L

    1999-01-20

    The theory of the double-edge lidar technique for measuring the wind with molecular backscatter is described. Two high-spectral-resolution edge filters are located in the wings of the Rayleigh-Brillouin profile. This doubles the signal change per unit Doppler shift, the sensitivity, and improves measurement accuracy relative to the single-edge technique by nearly a factor of 2. The use of a crossover region where the sensitivity of a molecular- and an aerosol-based measurement is equal is described. Use of this region desensitizes the molecular measurement to the effects of aerosol scattering over a velocity range of +/-100 m/s. We give methods for correcting short-term, shot-to-shot, frequency jitter and drift with a laser reference frequency measurement and methods for long-term frequency correction with a servo control system. The effects of Rayleigh-Brillouin scattering on the measurement are shown to be significant and are included in the analysis. Simulations for a conical scanning satellite-based lidar at 355 nm show an accuracy of 2-3 m/s for altitudes of 2-15 km for a 1-km vertical resolution, a satellite altitude of 400 km, and a 200 km x 200 km spatial resolution.

  19. Theory of the Double-Edge Molecular Technique for Doppler Lidar Wind Measurement

    Science.gov (United States)

    Flesia, Cristina; Korb, C. Laurence

    1999-01-01

    The theory of the double-edge lidar technique for measuring the wind with molecular backscatter is described. Two high-spectral-resolution edge filters are located in the wings of the Rayleigh Brillouin profile. This doubles the signal change per unit Doppler shift, the sensitivity, and improves measurement accuracy relative to the single-edge technique by nearly a factor of 2. The use of a crossover region where the sensitivity of a molecular- and an aerosol-based measurement is equal is described. Use of this region desensitizes the molecular measurement to the effects of aerosol scattering over a velocity range of 100 m s. We give methods for correcting short-term, shot-to-shot, frequency jitter and drift with a laser reference frequency measurement and methods for long-term frequency correction with a servo control system. The effects of Rayleigh Brillouin scattering on the measurement are shown to be significant and are included in the analysis. Simulations for a conical scanning satellite-based lidar at 355 nm show an accuracy of 2 3 m s for altitudes of 2 15 km for a 1-km vertical resolution, a satellite altitude of 400 km, and a 200 km 200 km spatial resolution.

  20. 1570 nm High Energy Fiber Laser Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This SBIR phase I project proposes a single frequency high energy fiber laser for remote sensing. Current state-of-art technologies can not provide all features of...

  1. Frequency standards

    CERN Document Server

    Riehle, Fritz

    2006-01-01

    Of all measurement units, frequency is the one that may be determined with the highest degree of accuracy. It equally allows precise measurements of other physical and technical quantities, whenever they can be measured in terms of frequency.This volume covers the central methods and techniques relevant for frequency standards developed in physics, electronics, quantum electronics, and statistics. After a review of the basic principles, the book looks at the realisation of commonly used components. It then continues with the description and characterisation of important frequency standards

  2. Design of Polymer Wavelength Splitter 1310 nm/1550 nm Based on Multimode Interferences

    Directory of Open Access Journals (Sweden)

    V. Prajzler

    2010-12-01

    Full Text Available We report about design of 1x2 1310/1550 nm optical wavelength division multiplexer based on polymer waveguides. The polymer splitter was designed by using RSoft software based on beam propagation method. Epoxy novolak resin polymer was used as core waveguides layer, silicon substrate with silica layer was used as buffer layer and polymethylmethacrylate was used as protection cover layer. The simulation shows that the output energy for the fundamental mode is 67.1 % for 1310 nm and 67.8 % for 1550 nm wavelength.

  3. Frequency Synthesiser

    NARCIS (Netherlands)

    Drago, Salvatore; Sebastiano, Fabio; Leenaerts, Dominicus M.W.; Breems, Lucien J.; Nauta, Bram

    2016-01-01

    A low power frequency synthesiser circuit (30) for a radio transceiver, the synthesiser circuit comprising: a digital controlled oscillator configured to generate an output signal having a frequency controlled by an input digital control word (DCW); a feedback loop connected between an output and an

  4. Frequency synthesiser

    NARCIS (Netherlands)

    Drago, S.; Sebastiano, Fabio; Leenaerts, Dominicus Martinus Wilhelmus; Breems, Lucien Johannes; Nauta, Bram

    2010-01-01

    A low power frequency synthesiser circuit (30) for a radio transceiver, the synthesiser circuit comprising: a digital controlled oscillator configured to generate an output signal having a frequency controlled by an input digital control word (DCW); a feedback loop connected between an output and an

  5. Passively mode-locked Nd:YVO4 laser operating at 1073 nm and 1085 nm

    Science.gov (United States)

    Waritanant, Tanant; Major, Arkady

    2018-02-01

    A passively mode-locked Nd:YVO4 laser operating at 1073 nm and 1085 nm was demonstrated with an intracavity birefringent filter as the wavelength selecting element. The average output powers achieved were 2.17 W and 2.18 W with optical-to-optical efficiency of 19.6% and 19.7%, respectively. The slope efficiencies were more than 31% at both output wavelengths. The pulse durations at the highest average output power were 10.3 ps and 8.4 ps, respectively. We believe that this is the first report of mode locking of a Nd:YVO4 laser operating at 1073 nm or 1085 nm lines.

  6. A radio-frequency single-electron transistor based on an InAs/InP heterostructure nanowire

    DEFF Research Database (Denmark)

    Nilsson, Henrik A.; Duty, Tim; Abay, Simon

    2008-01-01

    We demonstrate radio frequency single-electron transistors fabricated from epitaxially grown InAs/InP heterostructure nanowires. Two sets of double-barrier wires with different barrier thicknesses were grown. The wires were suspended 15 nm above a metal gate electrode. Electrical measurements...... on a high-resistance nanowire showed regularly spaced Coulomb oscillations at a gate voltage from −0.5 to at least 1.8 V. The charge sensitivity was measured to 32 µerms Hz−1/2 at 1.5 K. A low-resistance single-electron transistor showed regularly spaced oscillations only in a small gate-voltage region just...

  7. Comparison of high power large mode area and single mode 1908nm Tm-doped fiber lasers

    Science.gov (United States)

    Johnson, Benjamin R.; Creeden, Daniel; Limongelli, Julia; Pretorius, Herman; Blanchard, Jon; Setzler, Scott D.

    2016-03-01

    We compare large mode area (LMA) and single-mode (SM) double-clad fiber geometries for use in high power 1908nm fiber lasers. With a simple end-pumped architecture, we have generated 100W of 1908nm power with LMA fiber at 40% optical efficiency and 117W at 52.2% optical efficiency with single-mode fiber. We show the LMA fiber is capable of generating >200W and the SM fiber is capable of >300W at 1908nm. In all cases, the fiber lasers are monolithic power-oscillators with no free-space coupling.

  8. Reduction of skin effect losses in double-level-T-gate structure

    Energy Technology Data Exchange (ETDEWEB)

    Mikulics, M., E-mail: m.mikulics@fz-juelich.de; Hardtdegen, H.; Arango, Y. C.; Adam, R.; Fox, A.; Grützmacher, D. [Peter Grünberg Institute (PGI-9), Forschungszentrum Jülich, D-52425 Jülich (Germany); Jülich-Aachen Research Alliance, JARA, Fundamentals of Future Information Technology, D-52425 Jülich (Germany); Gregušová, D.; Novák, J. [Institute of Electrical Engineering, Slovak Academy of Sciences, SK-84104 Bratislava (Slovakia); Stanček, S. [Department of Nuclear Physic and Technique, Slovak University of Technology, SK-81219 Bratislava (Slovakia); Kordoš, P. [Institute of Electronics and Photonics, Slovak University of Technology, SK-81219 Bratislava (Slovakia); Sofer, Z. [Department of Inorganic Chemistry, Institute of Chemical Technology, Technická 5, Prague 6 (Czech Republic); Juul, L.; Marso, M. [Faculté des Sciences, de la Technologie et de la Communication, Université du Luxembourg, L-1359 Luxembourg (Luxembourg)

    2014-12-08

    We developed a T-gate technology based on selective wet etching yielding 200 nm wide T-gate structures used for fabrication of High Electron Mobility Transistors (HEMT). Major advantages of our process are the use of only standard photolithographic process and the ability to generate T-gate stacks. A HEMT fabricated on AlGaN/GaN/sapphire with gate length L{sub g} = 200 nm and double-stacked T-gates exhibits 60 GHz cutoff frequency showing ten-fold improvement compared to 6 GHz for the same device with 2 μm gate length. HEMTs with a double-level-T-gate (DLTG) structure exhibit up to 35% improvement of f{sub max} value compared to a single T-gate device. This indicates a significant reduction of skin effect losses in DLTG structure compared to its standard T-gate counterpart. These results agree with the theoretical predictions.

  9. International double taxation

    OpenAIRE

    Odarčenko, Michal

    2015-01-01

    1 Summary This thesis deals with the issue of international double taxation of income and capital and methods for its solution. International double taxation is an issue which states began to deal with in the late 19th century. This interest intensified after the First World War when also the League of Nations (predecessor of the United Nations) began to deal with international double taxation. Most attention the phenomenon of double taxation of income and capital with an international elemen...

  10. Double Outlet Right Ventricle

    Science.gov (United States)

    ... Right Ventricle Menu Topics Topics FAQs Double Outlet Right Ventricle Double outlet right ventricle (DORV) is a rare form of congenital heart disease. Article Info En español Double outlet right ventricle (DORV) is a rare form of congenital ...

  11. Hard pellicle study for 157-nm lithography

    Science.gov (United States)

    Shu, Emily Y.; Lo, Fu-Chang; Eschbach, Florence O.; Cotte, Eric P.; Engelstad, Roxann L.; Lovell, Edward G.; Okada, Kaname; Kikugawa, Shinya

    2002-07-01

    Identifying a functional pellicle solution for 157-nm lithography remains the most critical issue for mask technology. Developing a hard pellicle system has been a recent focus of study. Fabrication and potential pellicle-induced image placement errors present the highest challenges to the technology for meeting the stringent error budget for manufacturing devices in the 65-nm regime. This paper reports the results of a comprehensive proof-of-concept study on the state-of-art hard pellicle systems, which feature 800-mm thick modified fused silica pellicles and quartz frames. Pellicles were fabricated to ensure optical uniformity and flatness. Typical intrinsic warpage of these pellicles was close to the theoretical limit of 4.0 mm under a gravitational load. Quartz frames had bows less than 1.0 mm. The advantage of quartz frames with matched thermal expansion was demonstrated. An interferometric facility was developed to measure the flatness of the mask and pellicle system before and after pellicle mounting. Depending on the mounting process as well as mounting tool characteristics and techniques, variations were observed from pellicle to pellicle, mount to mount, and mask to mask. A redesign of the mounter and mounting process has significantly improved pellicle flatness. Finite element models were also generated to characterize the relative importance of the principal sources of pellicle-induced photomask distortions. Simulation results provide insightful guidance for improving image quality when employing a hard pellicle.

  12. High resolution mid-infrared spectroscopy based on frequency upconversion

    DEFF Research Database (Denmark)

    Dam, Jeppe Seidelin; Hu, Qi; Tidemand-Lichtenberg, Peter

    2013-01-01

    signals can be analyzed. The obtainable frequency resolution is usually in the nm range where sub nm resolution is preferred in many applications, like gas spectroscopy. In this work we demonstrate how to obtain sub nm resolution when using upconversion. In the presented realization one object point...... high resolution spectral performance by observing emission from hot water vapor in a butane gas burner....

  13. Timing Constraints Based High Performance Des Design And Implementation On 28nm FPGA

    DEFF Research Database (Denmark)

    Thind, Vandana; Pandey, Sujeet; Hussain, Dil muhammed Akbar

    2018-01-01

    in this work, we are going to implement DES Algorithm on 28nm Artix-7 FPGA. To achieve high performance design goal, we are using minimum period, maximum frequency, minimum low pulse, minimum high pulse for different cases of worst case slack, maximum delay, setup time, hold time and data skew path...

  14. SC-FDE for MMF short reach optical interconnects using directly modulated 850 nm VCSELs

    DEFF Research Database (Denmark)

    Teichmann, Victor S. C.; Barreto, Andre N.; Pham, Tien Thang

    2012-01-01

    We propose the use of single-carrier frequency-domain equalization (SC-FDE) for the compensation of modal dispersion in short distance optical links using multimode fibers and 850 nm VCSELs. By post-processing of experimental data, we demonstrate, at 7.9% overhead, the error-free transmission (ov...

  15. XUV-laser spectroscopy of HD at 92-98 nm.

    NARCIS (Netherlands)

    Hinnen, P.C.; Werners, S.E.; Stolte, S.; Hogervorst, W.; Ubachs, W.M.G.

    1995-01-01

    Sub-Doppler excitation spectra of HD have been recorded in the range 9298 nm with the use of a narrow-band and tunable extreme ultraviolet laser in combination with a molecular beam. Frequencies of 147 transitions to the B 1u+, C 1 u, and EF 1g+ states have been calibrated with an average absolute

  16. 980-nm 14-pin butterfly module dual-channel CW QW semiconductor laser for pumping

    Science.gov (United States)

    Deng, Yun; Yan, Changling; Qu, Yi; Li, Hui; Wang, Yuxia; Gao, Xin; Qiao, Zhongliang; Li, Mei; Qu, Bowen; Lu, Peng; Bo, Baoxue

    2010-10-01

    Nowadays, with its mature progress, the 790 nm - 1000 nm wavelength semiconductor laser is widely used in the fields of laser machining, laser ranging, laser radar, laser imaging, laser anti-counterfeit, biomedical and etc. Best of all, the 980 nm wavelength laser has its widespread application in the pumping source of Er3+ -doped fiber amplifier, optic fiber gyroscopes and other devices. The output wavelength of the fiber amplifier which takes the 980 nm wavelength laser as its pumping source is between 1060 nm and 1550 nm. This type of laser has its extremely wide range of applications in optical communication and other fields. Moreover, some new application domains keep constantly being developed. The semiconductor laser with the dual-channel ridge wave guide and the 980 nm emission wavelength is presented in this paper. In our work, we fabricated Lasers with the using of multi-quantum well (MQW) wafer grew by MBE, and the PL-wavelength of the MQW was 970 nm. The standard photofabrication method and the inductively coupled plasma (ICP) etching technology are adopted in the process of making dual-channel ridge wave guide with the width of 4 μm and height of 830 nm. In the state of continuous work at room temperature, the laser could output the single mode beam of 70 mW stably under the current of 100 mA. The threshold current of the laser diode is 17 mA and the slope efficiency is 0.89 W/A. The 3 dB spectrum bandwidth of the laser beam is 0.2 nm. This laser outputs its beam by a pigtail fiber on which Bragg grating for frequency stabilization is carved. The laser diode, the tail fiber, and the built-in refrigeration and monitoring modules are sealed in a 14-pin butterfly packaging. It can be used directly as the pumping source of Er3+ - doped fiber amplifier or optic fiber gyroscopes.

  17. Microsystem light source at 488 nm for shifted excitation resonance Raman difference spectroscopy.

    Science.gov (United States)

    Maiwald, Martin; Schmidt, Heinar; Sumpf, Bernd; Güther, Reiner; Erbert, Götz; Kronfeldt, Heinz-Detlef; Tränkle, Günther

    2009-11-01

    A microsystem light source emitting at 488 nm was tested and applied as a light source for shifted excitation resonance Raman difference spectroscopy (SERRDS). A nonlinear frequency conversion using a distributed feedback (DFB) diode laser emission at 976 nm and a periodically poled lithium niobate (PPLN) waveguide crystal was realized on a micro-optical bench with a footprint of 25 mm x 5 mm. Joint temperature management via the microbench is used for wavelength tuning. Two emission lines at 487.61 nm and 487.91 nm are used for the SERRDS experiments. The Raman spectra of the test sample polystyrene demonstrate that a laser bandpass filter did not need to be implemented. Resonance Raman spectra of Tartrazine (FD&C Yellow 5, E 102) in distilled water are presented to demonstrate the suitability of this light source for SERRDS in, e.g., food safety control.

  18. Compact corner-pumped Nd:YAG/YAG composite slab 1319 nm/1338 nm laser

    International Nuclear Information System (INIS)

    Liu, H; Gong, M; Wushouer, X; Gao, S

    2010-01-01

    A corner-pumped type is a new pumping type in the diode-pumped solid-state lasers, which has the advantages of high pump efficiency and favorable pump uniformity. A corner-pumped Nd:YAG/YAG composite slab continuous-wave 1319 nm/1338 nm dual-wavelength laser is first demonstrated in this paper. When the cavity length is 25 mm, the maximal output power is up to 7.62 W with a slope efficiency of 16.6% and an optical-to-optical conversion efficiency of 17%. The corresponding spectral line widths of 1319 nm laser and 1338 nm laser are 0.11 and 0.1 nm, respectively. The short-term instability of the output power is better than 1% when the pumping power is 39.5 W. The experimental results show that a corner-pumped type is a kind of feasible schedules in the design of diode-pumped solid-state 1.3 μm lasers with low or medium output powers

  19. Repair of near (365 nm)- and far (254 nm)- UV damage to bacteriophage of Escherichia coli

    International Nuclear Information System (INIS)

    Tyrrell, R.M.

    1979-01-01

    Intact bacteriophages were irradiated at 365 nm or 254 nm and then analyzed for DNA photoproducts or injected into their bacterial host to test susceptibility of the damage to both phage and host-cell mediated repair systems. Both thymine dimers and single-strand breaks were induced in the phage DNA by 365 nm radiation. The dimers appeared to be the major lethal lesion in both repair deficient bacteriophage T4 and bacteriophage lambda after 254 nm or 365 nm irradiation. Damage induced in T4 by either wavelength was equally susceptible to x-gene reactivation. v-gene reactivation acted on a larger fraction of the near-UV damage. The host-cell mediated photo-reactivation system was only slightly less effective for near-UV damage but host-cell reactivation (survival of phage lambda on uvr + and uvr - host) was effective against a far smaller section of near-UV damage than far-UV damage. Weigle-reactivation (far-UV induced) of near-UV damage to phage lambda was not observed. The results suggested that unless the near-UV damaged phage DNA is repaired immediately after injection, the lesions rapidly lose their susceptibility to repair with a consequent loss of activity of the phage particles. (author)

  20. Double layers in space

    International Nuclear Information System (INIS)

    Carlqvist, P.

    1982-01-01

    For more than a decade it has been realised that electrostatic double layers are likely to occur in space. The author briefly discusses the theoretical background of such double layers. Most of the paper is devoted to an account of the observational evidence for double layers in the ionosphere and magnetosphere of the Earth. Several different experiments are reviewed including rocket and satellite measurements and ground based observations. It is concluded that the observational evidence for double layers in space is very strong. The experimental results indicate that double layers with widely different properties may exist in space. (Auth.)

  1. High-speed stimulated Brillouin scattering spectroscopy at 780 nm

    Directory of Open Access Journals (Sweden)

    Itay Remer

    2016-09-01

    Full Text Available We demonstrate a high-speed stimulated Brillouin scattering (SBS spectroscopy system that is able to acquire stimulated Brillouin gain point-spectra in water samples and Intralipid tissue phantoms over 2 GHz within 10 ms and 100 ms, respectively, showing a 10-100 fold increase in acquisition rates over current frequency-domain SBS spectrometers. This improvement was accomplished by integrating an ultra-narrowband hot rubidium-85 vapor notch filter in a simplified frequency-domain SBS spectrometer comprising nearly counter-propagating continuous-wave pump-probe light at 780 nm and conventional single-modulation lock-in detection. The optical notch filter significantly suppressed stray pump light, enabling detection of stimulated Brillouin gain spectra with substantially improved acquisition times at adequate signal-to-noise ratios (∼25 dB in water samples and ∼15 dB in tissue phantoms. These results represent an important step towards the use of SBS spectroscopy for high-speed measurements of Brillouin gain resonances in scattering and non-scattering samples.

  2. Nantenna for Standard 1550 nm Optical Communication Systems

    Directory of Open Access Journals (Sweden)

    Waleed Tariq Sethi

    2016-01-01

    Full Text Available Nanoscale transmission and reception technologies will play a vital role and be part of the next generation communication networks. This applies for all application fields including imaging, health, biosensing, civilian, and military communications. The detection of light frequency using nanooptical antennas may possibly become a good competitor to the semiconductor based photodetector because of the simplicity of integration, cost, and inherent capability to detect the phase and amplitude instead of power only. In this paper, authors propose simulated design of a hexagonal dielectric loaded nantenna (HDLN and explore its potential benefits at the standard optical C-band (1550 nm. The proposed nantenna consists of “Ag-SiO2-Ag” structure, consisting of “Si” hexagonal dielectric with equal lengths fed by “Ag” nanostrip transmission line. The simulated nantenna achieves an impedance bandwidth of 3.7% (190.9 THz–198.1 THz and a directivity of 8.6 dBi, at a center frequency of 193.5 THz, covering most of the ITU-T standard optical transmission window (C-band. The hexagonal dielectric nantenna produces HE20δ modes and the wave propagation is found to be end-fire. The efficiency of the nantenna is proven via numerical expressions, thus making the proposed design viable for nanonetwork communications.

  3. 308-nm excimer laser in endodontics

    Science.gov (United States)

    Liesenhoff, Tim

    1992-06-01

    Root canal preparation was performed on 20 extracted human teeth. After opening the coronal pulp, the root canals were prepared by 308 nm excimer laser only. All root canals were investigated under SEM after separation in the axial direction. By sagittal separation of the mandibles of freshly slaughtered cows, it was possible to get access to the tissues and irradiate under optical control. Under irradiation of excimer laser light, tissue starts to fluoresce. It was possible to demonstrate that each tissue (dentin, enamel, bone, pulpal, and connective tissue) has a characteristic spectral pattern. The SEM analyses showed that it is well possible to prepare root canals safely. All organic soft tissue has been removed by excimer laser irradiation. There was no case of via falsa. The simultaneous spectroscopic identification of the irradiated tissue provides a safe protection from overinstrumentation. First clinical trials on 20 patients suffering of chronical apical parodontitis have been carried out successfully.

  4. Optical absorption of silicon nitride membranes at 1064 nm and at 1550 nm

    Science.gov (United States)

    Steinlechner, Jessica; Krüger, Christoph; Martin, Iain W.; Bell, Angus; Hough, Jim; Kaufer, Henning; Rowan, Sheila; Schnabel, Roman; Steinlechner, Sebastian

    2017-07-01

    Because of a low mechanical loss, thin films made of silicon nitride (Si3N4 ) are interesting for fundamental research and development in the field of gravitational-wave detection. Si3N4 membranes allow for the characterization of quantum radiation pressure noise (RPN), which will be a limiting noise source in gravitational-wave detectors of the second and third generations. Furthermore, Si3N4 is an interesting material for possible thermal noise reduction in highly reflective mirror coatings. For both applications, the optical absorption of Si3N4 needs to be low. This paper presents absorption measurements on low-stress Si3N4 membranes showing an absorption a factor of 7 lower at 1550 nm than at 1064 nm resulting in an estimated 2 times higher sensitivity in RPN experiments at the higher wavelength and making Si3N4 an interesting material for highly reflective multimaterial mirror coatings at 1550 nm.

  5. Tunnel magnetoresistance in double spin filter junctions

    International Nuclear Information System (INIS)

    Saffarzadeh, Alireza

    2003-01-01

    We consider a new type of magnetic tunnel junction, which consists of two ferromagnetic tunnel barriers acting as spin filters (SFs), separated by a nonmagnetic metal (NM) layer. Using the transfer matrix method and the free-electron approximation, the dependence of the tunnel magnetoresistance (TMR) on the thickness of the central NM layer, bias voltage and temperature in the double SF junction are studied theoretically. It is shown that the TMR and electron-spin polarization in this structure can reach very large values under suitable conditions. The highest value of the TMR can reach 99%. By an appropriate choice of the thickness of the central NM layer, the degree of spin polarization in this structure will be higher than that of the single SF junctions. These results may be useful in designing future spin-polarized tunnelling devices

  6. Low k1 lithography patterning option for the 90-nm and 65-nm nodes

    Science.gov (United States)

    Hsu, Stephen D.; Van Den Broeke, Douglas J.; Shi, Xuelong; Hsu, Michael; Wampler, Kurt E.; Chen, J. Fung; Yu, Annie; Yang, Samuel C.; Hsieh, Frank

    2003-08-01

    As IC fabrication processes are maturing for the 130nm node, silicon manufacturers are focusing on 90nm device manufacturing at ever-lower k1 factors. Driven by cost savings, many integrated device manufacturers (IDMs) and foundries are working toward patterning critical mask layers of 90nm designs using high numerical aperture KrF exposure tools. The goal of this study is to find out whether KrF can be successfully used instead of ArF for fabricating 90nm devices. This exercise will help to gain learning for the upcoming 65nm node, where the early manufacturing phase will also be carried out at similar k1 near 0.3. For high volume wafer production, the cost and throughput are in favor of using a single exposure PSM technique. For low-volume, the high mask cost of Alt-PSM discourages its use. What are the most sensible KrF lithography patterning options at k1 = 0.3? For single exposure mask solutions at the 90nm node using KrF, there are two leading candidates: 6% attenuated PSM (Att-PSM) and Chromeless Phase Lithography (CPL). In this work, we explored and compared these two options in terms of the best achievable process latitude for patterning poly gate layer. First, we analyzed the diffraction patterns from 6% Att-PSM and CPL mask features and identified the optimum transmission for various pitches. Next, we examined the two options from a mask making perspective, accessing mask manufacturability, phase and transmission error control, defect sources, etc. In this paper, we describe how hybrid CPL can be used as a variable transmission mask to produce the best through pitch imaging performance and a practical implementation method for mask manufacturing.

  7. Simulation of 50-nm Gate Graphene Nanoribbon Transistors

    Directory of Open Access Journals (Sweden)

    Cedric Nanmeni Bondja

    2016-01-01

    Full Text Available An approach to simulate the steady-state and small-signal behavior of GNR MOSFETs (graphene nanoribbon metal-semiconductor-oxide field-effect transistor is presented. GNR material parameters and a method to account for the density of states of one-dimensional systems like GNRs are implemented in a commercial device simulator. This modified tool is used to calculate the current-voltage characteristics as well the cutoff frequency fT and the maximum frequency of oscillation fmax of GNR MOSFETs. Exemplarily, we consider 50-nm gate GNR MOSFETs with N = 7 armchair GNR channels and examine two transistor configurations. The first configuration is a simplified MOSFET structure with a single GNR channel as usually studied by other groups. Furthermore, and for the first time in the literature, we study in detail a transistor structure with multiple parallel GNR channels and interribbon gates. It is shown that the calculated fT of GNR MOSFETs is significantly lower than that of GFETs (FET with gapless large-area graphene channel with comparable gate length due to the mobility degradation in GNRs. On the other hand, GNR MOSFETs show much higher fmax compared to experimental GFETs due the semiconducting nature of the GNR channels and the resulting better saturation of the drain current. Finally, it is shown that the gate control in FETs with multiple parallel GNR channels is improved while the cutoff frequency is degraded compared to single-channel GNR MOSFETs due to parasitic capacitances of the interribbon gates.

  8. Both active and sham low-frequency rTMS single sessions over the right DLPFC decrease cue-induced cravings among pathological gamblers seeking treatment: A randomized, double-blind, sham-controlled crossover trial.

    Science.gov (United States)

    Sauvaget, Anne; Bulteau, Samuel; Guilleux, Alice; Leboucher, Juliette; Pichot, Anne; Valrivière, Pierre; Vanelle, Jean-Marie; Sébille-Rivain, Véronique; Grall-Bronnec, Marie

    2018-02-21

    Background Craving is a core symptom of addictive disorders, such as pathological gambling for example. Over the last decade, several studies have assessed the efficacy of repetitive transcranial magnetic stimulation (rTMS) in the addiction field, which triggers the dorsolateral prefrontal cortex (DLPFC) to decrease craving. The STIMJEU study investigated whether a single session of low-frequency (LF, i.e., 1 Hz) rTMS applied to the right DLPFC reduced cue-induced gambling craving in a sample of treatment-seeking pathological gamblers. Methods Thirty patients received both active and sham rTMS in random order and were blinded to the condition in a within-subject crossover design. Outcome measures included self-reported gambling craving (Visual Analog Scale and Gambling Craving Scale) and physiological measures (heart rate and blood pressure). Results The rTMS sessions were associated with a significant decrease in the gambling urge, regardless of whether the session was active or sham. When controlling cue-induced craving levels, no effects were observed on craving for active rTMS. Overall, rTMS was well-tolerated, and the credibility of the sham procedure was assessed and appeared to be appropriate. Conclusions We failed to demonstrate the specific efficacy of one session of LF rTMS to decrease cue-induced craving in pathological gamblers. A strong placebo-effect and rTMS parameters may partly explain these results. Yet, we are convinced that rTMS remains a promising therapeutic method. Further studies are required to examine its potential effect.

  9. Extending the wavelength range of single-emitter diode lasers for medical and sensing applications: 12xx-nm quantum dots, 2000-nm wells, > 5000-nm cascade lasers

    Science.gov (United States)

    Crump, Paul; Patterson, Steve; Elim, Sandrio; Zhang, Shiguo; Bougher, Mike; Patterson, Jason; Das, Suhit; Dong, Weimin; Grimshaw, Mike; Wang, Jun; Wise, Damian; DeFranza, Mark; Bell, Jake; Farmer, Jason; DeVito, Mark; Martinsen, Rob; Kovsh, Alexey; Toor, Fatima; Gmachl, Claire F.

    2007-02-01

    Diode lasers supply high power densities at wavelengths from 635-nm to 2000-nm, with different applications enabled by providing this power at different wavelengths. As the range of available wavelengths broadens, many novel medical and atmospheric applications are enabled. Traditional quantum well lasers provide high performance in the range 635- nm to 1100-nm range for GaAs-based devices and 1280-nm to 2000-nm for InP, leaving a notable gap in the 1100 to 1280-nm range. There are many important medical and sensing applications in this range and quantum dots produced using Stranski-Krastanow self-organized MBE growth on GaAs substrates provide an alternative high performance solution. We present results confirming broad area quantum dot lasers can deliver high optical powers of 16-W per emitter and high power conversion efficiency of 35% in this wavelength range. In addition, there are growing applications for high power sources in wavelengths > 1500-nm. We present a brief review of our current performance status in this wavelength range, both with conventional quantum wells in the 1500-nm to 2500-nm range and MOCVD grown quantum cascade lasers for wavelengths > 4000-nm. At each wavelength, we review the designs that deliver this performance, prospects for increased performance and the potential for further broadening the availability of novel wavelengths for high power applications.

  10. Raman Probe Based on Optically-Poled Double-Core Fiber

    DEFF Research Database (Denmark)

    Brunetti, Anna Chiara; Margulis, Walter; Rottwitt, Karsten

    2012-01-01

    A Raman probe based on an optically-poled double-core fiber. In-fiber SHG allows for Raman spectroscopy of DMSO at 532nm when illuminating the fiber with 1064nm light. The fiber structure provides independent excitation and collection paths.......A Raman probe based on an optically-poled double-core fiber. In-fiber SHG allows for Raman spectroscopy of DMSO at 532nm when illuminating the fiber with 1064nm light. The fiber structure provides independent excitation and collection paths....

  11. Anomalous variations of NmF2 over the Argentine Islands: a statistical study

    Directory of Open Access Journals (Sweden)

    A. V. Pavlov

    2009-04-01

    Full Text Available We present a statistical study of variations in the F2-layer peak electron density, NmF2, and altitude, hmF2, over the Argentine Islands ionosonde. The critical frequencies, foF2, and, foE, of the F2 and E-layers, and the propagation factor, M(3000F2, measured by the ionosonde during the 1957–1959 and 1962–1995 time periods were used in the statistical analysis to determine the values of NmF2 and hmF2. The probabilities to observe maximum and minimum values of NmF2 and hmF2 in a diurnal variation of the electron density are calculated. Our study shows that the main part of the maximum diurnal values of NmF2 is observed in a time sector close to midnight in November, December, January, and February exhibiting the anomalous diurnal variations of NmF2. Another anomalous feature of the diurnal variations of NmF2 exhibited during November, December, and January when the minimum diurnal value of NmF2 is mainly located close to the noon sector. These anomalous diurnal variations of NmF2 are found to be during both geomagnetically quiet and disturbed conditions. Anomalous features are not found in the diurnal variations of hmF2. The statistical study of the NmF2 winter anomaly phenomena over the Argentine Islands ionosonde was carried out. The variations in a maximum daytime value, R, of a ratio of a geomagnetically quiet daytime winter NmF2 to a geomagnetically quiet daytime summer NmF2 taken at a given UT and for approximately the same level of solar activity were studied. The conditional probability of the occurrence of R in an interval of R, the most frequent value of R, the mean expected value of R, and the conditional probability to observe the F2-region winter anomaly during a daytime period were calculated for low, moderate, and high solar activity. The calculations show that the mean expected value of R and the occurrence frequency of the F2-region winter anomaly increase with increasing solar activity.

  12. Magnetic properties of double perovskite La2BMnO6 (B = Ni or Co) nanoparticles.

    Science.gov (United States)

    Mao, Yuanbing; Parsons, Jason; McCloy, John S

    2013-06-07

    Double perovskite La2BMnO6 (B = Ni and Co) nanoparticles with average particle size of ~50 nm were synthesized using a facile, environmentally friendly, and scalable molten-salt reaction at 700 °C in air. Their structural and morphological properties were characterized by X-ray diffraction and transmission electron microscopy. Their magnetic properties were evaluated and compared using dc magnetic M-T and M-H, and ac magnetic susceptibility versus frequency, temperature, and field for the first time. The dc magnetization curves show paramagnetic-ferromagnetic transitions at TC∼ 275 and 220 K for La2NiMnO6 (LNMO) and La2CoMnO6 (LCMO) nanoparticles, respectively. ac susceptibility revealed that the LCMO nanoparticles had a single magnetic transition indicative of Co(2+)-O(2-)-Mn(4+) ordering, whereas the LNMO nanoparticles showed more complex magnetic behaviors suggesting a re-entrant spin glass.

  13. Challenges in the Plasma Etch Process Development in the sub-20nm Technology Nodes

    Science.gov (United States)

    Kumar, Kaushik

    2013-09-01

    For multiple generations of semiconductor technologies, RF plasmas have provided a reliable platform for critical and non-critical patterning applications. The electron temperature of processes in a RF plasma is typically several electron volts. A substantial portion of the electron population is within the energy range accessible for different types of electron collision processes, such as electron collision dissociation and dissociative electron attachment. When these electron processes occur within a small distance above the wafer, the neutral species, radicals and excited molecules, generated from these processes take part in etching reactions impacting selectivity, ARDE and micro-loading. The introduction of finFET devices at 22 nm technology node at Intel marks the transition of planar devices to 3-dimensional devices, which add to the challenges to etch process in fabricating such devices. In the sub-32 nm technology node, Back-end-of-the-line made a change with the implementation of Trench First Metal Hard Mask (TFMHM) integration scheme, which has hence gained traction and become the preferred integration of low-k materials for BEOL. This integration scheme also enables Self-Aligned Via (SAV) patterning which prevents via CD growth and confines via by line trenches to better control via to line spacing. In addition to this, lack of scaling of 193 nm Lithography and non-availability of EUV based lithography beyond concept, has placed focus on novel multiple patterning schemes. This added complexity has resulted in multiple etch schemes to enable technology scaling below 80 nm Pitches, as shown by the memory manufacturers. Double-Patterning and Quad-Patterning have become increasingly used techniques to achieve 64 nm, 56 nm and 45 nm Pitch technologies in Back-end-of-the-line. Challenges associated in the plasma etching of these multiple integration schemes will be discussed in the presentation. In collaboration with A. Ranjan, TEL Technology Center, America

  14. Quadratic Electro-Optic Effect in the Nonconjugated Conductive Co-polymer Iodine-doped Styrene-Butadiene-Rubber Measured at 633 nm and 1550 nm

    Science.gov (United States)

    Telang, Gurudutt; Thakur, Mrinal

    2012-02-01

    The quadratic electro-optic effect in the nonconjugated conductive co-polymer film of styrene-butadiene-rubber (SBR) has been measured using field-induced birefringence method. Thin films of styrene-butadiene-rubber have been prepared on various substrates from a chloroform solution and characterized using optical absorption spectroscopy, FTIR and DSC before and after doping with iodine. The optical absorption spectrum at low doping shows two peaks: one at 4.27 eV and the other at 3.2 eV corresponding to the radical cation and charge-transfer transition. FTIR data indicate =C-H vibration bands (964 cm-1 and 910 cm-1) of polybutadiene decrease upon doping due to transformation of the double bonds into radical cations. The Kerr coefficients as measured at 633 nm and at 1550 nm are 3.1x10-10 m/V^2 and 1.3x10-10 m/V^2 respectively. These exceptionally large values have been attributed to the subnanometer metallic domains formed upon doping and charge-transfer involving isolated double-bonds.

  15. Frequency-swept Light Sources for Optical Coherence Tomography in the 1060nm range

    DEFF Research Database (Denmark)

    Marschall, Sebastian

    Optical coherence tomography (OCT) is a non-invasive imaging technique for visualizing the internal structure of scattering materials, such as biological tissues. It generates two- or three-dimensional images of the sample with cellular (micrometer) resolution. OCT has become an important instrum...

  16. Temperature sensitivity of differential absorption lidar measurements of water vapor in the 720-nm region

    Science.gov (United States)

    Browell, Edward V.; Ismail, Syed; Grossmann, Benoist E.

    1991-01-01

    Recently measured properties of water vapor (H2O) absorption lines have been used in calculations to evalute the temperature sensitivity of differential absorption lidar (Dial) H2O measurements. This paper estimates the temperature sensitivity of H2O lines in the 717-733-nm region for both H2O mixing ratio and number density measurements, and discusses the influence of the H2O line ground state energies E-double-prime, the H2O absorption linewidths, the linewidth temperature dependence parameter, and the atmospheric temperature and pressure variations with altitude and location on the temperature sensitivity calculations. Line parameters and temperature sensitivity calculations for 67 H2O lines in the 720-nm band are given which can be directly used in field experiments. Water vapor lines with E-double-prime values in the 100-300/cm range were found to be optimum for Dial measurements of H2O number densities, while E-double-prime values in the 250-500/cm range were found to be optimum for H2O mixing ratio measurements.

  17. High-power FDML laser for swept source-OCT at 1060 nm

    DEFF Research Database (Denmark)

    Marschall, Sebastian; Klein, Thomas; Wieser, Wolfgang

    2010-01-01

    We present a novel frequency-swept light source working at 1060nm that utilizes a tapered amplifier as gain medium. These devices feature significantly higher saturation power than conventional semiconductor optical amplifiers and can thus improve the limited output power of swept sources...... in this wavelength range. We demonstrate that a tapered amplifier can be integrated into a fiber-based swept source and allows for high-speed FDML operation. The developed light source operates at a sweep rate of 116kHz with an effective average output power in excess of 30mW. With a total sweep range of 70 nm...

  18. Wide temperature operation of 850-nm VCSEL and isolator-free operation of 1300-nm VCSEL for a variety of applications

    Science.gov (United States)

    Nishikata, Kevin; Ariga, Maiko; Iwai, Norihiro; Ikenaga, Yoshihiko; Setiagung, Casimirus; Kageyama, Takeo; Shimizu, Hitoshi; Yokouchi, Noriyuki; Kasukawa, Akihiko; Koyama, Fumio

    2005-03-01

    Furukawa Electric is looking at a variety of applications using VCSEL. New applications such as sensors, automobile, and home electric appliances require new characteristics of stable CW operation, higher modulation, wider temperature range, and higher density array. Automobile Local Area Network called MOST (Media Orientated System Transport) is now popular using 650 nm LED plus Plastic Optical Fiber with a 1 mm core. For higher operation temperature and higher transmission speed, the system with 850 nm VCSEL plus HCS (Hard Clad Silica) fiber with a core of 200 microns Silica has been investigating. We investigated 850 nm oxide VCSEL performances of LI, RIN, Eye, BERT and reliability in a wide temperature range from -40 to 125°C In order to obtain low-cost modules for data-communication, it is critical to eliminate high-cost components such as an isolator and a lens containing in the module. We confirmed 2.5 Gbps stable operation without the isolator for 1300 nm GaInNAsSb oxide VCSEL experimentally and theoretically. The RIN was stable around -145 dB/Hz with an optical feedback light less than -30 dB and drastically increased at this point. It was -110 dB/Hz with -13 dB. For an increasing demand of high bandwidth for the interconnection between computers and routers, it is important to investigate the maximum frequency of an existing 1300 nm GaInNAsSb VCSEL. We showed the intrinsic maximum modulation frequency of 23 GHz by fitting K-factor that was 0.385 nsec.

  19. RFA-based 589-nm guide star lasers for ESO VLT: a paradigm shift in performance, operational simplicity, reliability, and maintenance

    Science.gov (United States)

    Friedenauer, Axel; Karpov, Vladimir; Wei, Daoping; Hager, Manfred; Ernstberger, Bernhard; Clements, Wallace R. L.; Kaenders, Wilhelm G.

    2012-07-01

    Large telescopes equipped with adaptive optics require 20-25W CW 589-nm sources with emission linewidths of ~5 MHz. These Guide Star (GS) lasers should also be highly reliable and simple to operate and maintain for many years at the top of a mountain facility. Under contract from ESO, industrial partners TOPTICA and MPBC are nearing completion of the development of GS lasers for the ESO VLT, with delivery of the first of four units scheduled for December 2012. We report on the design and performance of the fully-engineered Pre-Production Unit (PPU), including system reliability/availability analysis, the successfully-concluded qualification testing, long-term component and system level tests and long-term maintenance and support planning. The chosen approach is based on ESO's patented narrow-band Raman Fiber Amplifier (EFRA) technology. A master oscillator signal from a linearly-polarized TOPTICA 20-mW, 1178-nm CW diode laser, with stabilized emission frequency and controllable linewidth up to a few MHz, is amplified in an MPBC polarization-maintaining (PM) RFA pumped by a high-power 1120-nm PM fiber laser. With efficient stimulated Brillouin scattering suppression, an unprecedented 40W of narrow-band RFA output has been obtained. This is then mode-matched into a resonant-cavity doubler with a free-spectral-range matching the sodium D2a to D2b separation, allowing simultaneous generation of an additional frequency component (D2b line) to re-pump the sodium atom electronic population. With this technique, the return flux can be increased without having to resort to electro-optical modulators and without the risk of introducing optical wave front distortions. The demonstrated output powers with doubling efficiencies >80% at 589 nm easily exceed the 20W design goal and require less than 700 W of electrical power. In summary, the fiber-based guide star lasers provide excellent beam quality and are modular, turn-key, maintenance-free, reliable, efficient, and ruggedized

  20. The 890 nm Band of Methane

    Science.gov (United States)

    Spickler, Philip T.; Benner, D.; O'Brien, J.; Devi, V.; Shaji, S.; Houck, C.; Coakley, J.

    2010-01-01

    The near infrared bands of methane were the first observed in the outer planets and Titan. With the very long paths of rays in this spectral region within the atmospheres of these objects, scattering and pressure and temperature inhomogeneities are important. Here the spectrum is very complex and long absorption paths in the laboratory are difficult to cool to outer solar system temperatures. Many significant spectral lines appear per Doppler width, so the absorption is usually modeled statistically. The problem with these statistical models is that violations of the modeling assumptions can cause the extrapolation of laboratory parameters to predict absorption that diverges from the actual. These models generally do not provide transmissions that are multiplicative, so scattering and inhomogeneous atmospheres cannot be properly modeled. The intracavity laser spectrometer of the University of Missouri-St. Louis was used to obtain low temperature (99-161K), low pressure (0.12-7.13 Torr), long path (3.14-5.65 km) and high resolution ( 0.01 cm-1 HWHM) spectra of methane covering the entire 890nm feature (10925-11500 cm-1), the deepest band in the CCD spectral region. At these temperatures the spectral lines originating from higher energy levels are not visible and the Doppler width is decreased substantially from room temperature. The result is a dense, but manageable spectrum from which line positions, intensities and lower state energies are derived on a line by line basis by the William and Mary multispectrum nonlinear least squares fitting program, allowing for the simulation of the spectrum at infinite resolution for any physical conditions with temperature less than 160K. A sample spectrum will be shown. Support for work at William and Mary provided by NASA through grant NNX08AF06G. Support for work at UM-St. Louis provided by NASA through grant NAG5-12013, from NSF through grant CHE-0213356 and by the University of Missouri Research Board.

  1. EFFECT OF ASE ON PERFORMANCE OF TDFA FOR 1479 nm-1555 nm WAVELENGTH RANGE

    Directory of Open Access Journals (Sweden)

    INDERPREET KAUR

    2017-08-01

    Full Text Available In this paper, mathematical modelling of TDFA for broadened gain spectrum and reduced noise figure has been carried out by keeping all practical parameters in consideration. A model of TDFA has been designed based on simulation after considering all the major parameters like ASE pump and signal power. The present research claims to support 96 DWDM channels across 1479 nm-1555 nm wavelength range, with a peak gain of 26 dB (without ASE and with a peak gain 24 dB, ASE of 1.5 dBm for optimum fiber length of TDF as 10 m. With this proposed model, the gain of 24 dB and NF of 7 dB has been achieved.

  2. Narrowband Er:YAG nonplanar ring oscillator at 1645 nm.

    Science.gov (United States)

    Chen, Da-Wun; Belden, Paul M; Rose, Todd S; Beck, Steven M

    2011-04-01

    We report 1645 nm narrowband operation of a monolithic Er:YAG nonplanar ring oscillator resonantly pumped at 1532 nm. Unidirectional cw power up to 0.5 W was obtained with a measured linewidth of 21 kHz.

  3. TUNABLE DIODE LASER MEASUREMENTS OF NO2 NEAR 670 NM AND 395 NM. (R823933)

    Science.gov (United States)

    Two single-mode diode lasers were used to record high-resolution absorption spectra of NO2 (dilute in Ar) near 670.2 and 394.5 nm over a range of temperatures (296 to 774 K) and total pressures (2.4 x 10(-2) to 1 atm). A commercial InGaAsP laser was tuned 1.3 cm(-1) at a repetiti...

  4. Ion Exclusion by Sub 2-nm Carbon Nanotube Pores

    Energy Technology Data Exchange (ETDEWEB)

    Fornasiero, F; Park, H G; Holt, J K; Stadermann, M; Grigoropoulos, C P; Noy, A; Bakajin, O

    2008-04-09

    Carbon nanotubes offer an outstanding platform for studying molecular transport at nanoscale, and have become promising materials for nanofluidics and membrane technology due to their unique combination of physical, chemical, mechanical, and electronic properties. In particular, both simulations and experiments have proved that fluid flow through carbon nanotubes of nanometer size diameter is exceptionally fast compared to what continuum hydrodynamic theories would predict when applied on this length scale, and also, compared to conventional membranes with pores of similar size, such as zeolites. For a variety of applications such as separation technology, molecular sensing, drug delivery, and biomimetics, selectivity is required together with fast flow. In particular, for water desalination, coupling the enhancement of the water flux with selective ion transport could drastically reduce the cost of brackish and seawater desalting. In this work, we study the ion selectivity of membranes made of aligned double-walled carbon nanotubes with sub-2 nm diameter. Negatively charged groups are introduced at the opening of the carbon nanotubes by oxygen plasma treatment. Reverse osmosis experiments coupled with capillary electrophoresis analysis of permeate and feed show significant anion and cation rejection. Ion exclusion declines by increasing ionic strength (concentration) of the feed and by lowering solution pH; also, the highest rejection is observed for the A{sub m}{sup Z{sub A}} C{sub n}{sup Z{sub C}} salts (A=anion, C=cation, z= valence) with the greatest Z{sub A}/Z{sub C} ratio. Our results strongly support a Donnan-type rejection mechanism, dominated by electrostatic interactions between fixed membrane charges and mobile ions, while steric and hydrodynamic effects appear to be less important. Comparison with commercial nanofiltration membranes for water softening reveals that our carbon nanotube membranes provides far superior water fluxes for similar ion

  5. Overlay metrology for double patterning processes

    Science.gov (United States)

    Leray, Philippe; Cheng, Shaunee; Laidler, David; Kandel, Daniel; Adel, Mike; Dinu, Berta; Polli, Marco; Vasconi, Mauro; Salski, Bartlomiej

    2009-03-01

    The double patterning (DPT) process is foreseen by the industry to be the main solution for the 32 nm technology node and even beyond. Meanwhile process compatibility has to be maintained and the performance of overlay metrology has to improve. To achieve this for Image Based Overlay (IBO), usually the optics of overlay tools are improved. It was also demonstrated that these requirements are achievable with a Diffraction Based Overlay (DBO) technique named SCOLTM [1]. In addition, we believe that overlay measurements with respect to a reference grid are required to achieve the required overlay control [2]. This induces at least a three-fold increase in the number of measurements (2 for double patterned layers to the reference grid and 1 between the double patterned layers). The requirements of process compatibility, enhanced performance and large number of measurements make the choice of overlay metrology for DPT very challenging. In this work we use different flavors of the standard overlay metrology technique (IBO) as well as the new technique (SCOL) to address these three requirements. The compatibility of the corresponding overlay targets with double patterning processes (Litho-Etch-Litho-Etch (LELE); Litho-Freeze-Litho-Etch (LFLE), Spacer defined) is tested. The process impact on different target types is discussed (CD bias LELE, Contrast for LFLE). We compare the standard imaging overlay metrology with non-standard imaging techniques dedicated to double patterning processes (multilayer imaging targets allowing one overlay target instead of three, very small imaging targets). In addition to standard designs already discussed [1], we investigate SCOL target designs specific to double patterning processes. The feedback to the scanner is determined using the different techniques. The final overlay results obtained are compared accordingly. We conclude with the pros and cons of each technique and suggest the optimal metrology strategy for overlay control in double

  6. High-resolution photoabsorption cross section measurements of sulfur dioxide between 198 nm and 325 nm

    Science.gov (United States)

    Stark, Glenn; Smith, Peter; Blackie, Douglas; Blackwell-Whitehead, Richard; Pickering, Juliet; Rufus, James; Thorne, Anne

    Accurate photoabsorption cross section data at a range of temperatures are required for the incorporation of sulfur dioxide into atmospheric photochemical models. In addition to its role in the terrestrial atmosphere, sulfur dioxide is observed in significant concentrations in the atmospheres of Venus and Io. Our laboratory measurement program focuses on the very congested SO2 spectrum in the ultraviolet. Using the Imperial College UV Fourier transform spectrometer, we have recorded high-resolution (resolving power (λ/∆λ) = 450,000) absorption spectra in the 198 to 325 nm region over a range of temperatures from 160 K to 295 K. This high resolving power allows resolutions approaching those required to fully resolve the Doppler profile of SO2 in the UV. We have reported absolute photoabsorption cross sections at 295 K [Stark et al., JGR Planets 104, 16585 (1999); Rufus et al. JGR Planets 108, doi:10.1029/2002JE001931,(2003)]. Further measurements, at 160 K in the 198 to 200 nm region and at 195 K in the 220 to 325 nm region, have been recorded and analyzed. We present an overview of our new measured cross sections at temperatures and pressures comparable to those found in planetary atmospheres. This work was supported in part by NASA Grant NNG05GA03G, PPARC (UK), and the Leverhulme Trust.

  7. Double deflation and aggregation

    NARCIS (Netherlands)

    Dietzenbacher, Erik; Hoen, A.R.

    Published input-output tables in constant prices are relatively scarce. Therefore, input-output tables often have to be deflated by the practitioners themselves. The method of double deflation is used predominantly for this purpose. The present paper shows that the double-deflation method is subject

  8. Double layer formation

    International Nuclear Information System (INIS)

    Singh, N.

    1982-01-01

    Results from several numerical simulations of the formation of double layers in plasmas with a constant potential drop across them are presented. Here the emphasis is mainly on plasma processes during the formation of double layers. The recurring formation of double layers, their propagation and associated current interruptions are observed when the electron current injected into the simulation region from the low potential side exceeds the electron thermal current. This recurring process is stopped (or delayed) when the electron current recuperation is inhibited by a small magnetic force on the electrons. The motion of double layers is examined and it is found that the motion is caused by the interruption of the ion current from the high potential side. The subsequent recovery of this current renders the double layer stationary. (author)

  9. A dual-loss-modulated intra-cavity frequency-doubled Q-switched and mode-locked Nd:Lu0.15Y0.85VO4/KTP green laser with a single-walled carbon nanotube saturable absorber and an acousto-optic modulator

    International Nuclear Information System (INIS)

    Zhang, Gang; Zhao, Shengzhi; Yang, Kejian; Li, Guiqiu; Li, Dechun; Cheng, Kang; Han, Chao; Zhao, Bin; Wang, Yonggang

    2011-01-01

    By using both a single-walled carbon nanotube saturable absorber (SWCNT-SA) and an acousto-optic (AO) modulator, a dual-loss-modulated intra-cavity frequency-doubled Q-switched and mode-locked (QML) Nd:Lu 0.15 Y 0.85 VO 4 /KTP (KTiOPO 4 ) green laser was demonstrated for the first time. The QML green laser characteristics such as the pulse width and single-pulse energy have been measured for different modulation frequencies of the AO modulator (f p ). In particular, in comparison with the solely passively QML green laser with an SWCNT-SA, the dual-loss-modulated QML green laser can generate a more stable pulse train, a shorter pulse width of the Q-switched envelope, a greater pulse energy and a higher average peak power. For the dual-loss-modulated QML green laser, at a pump power of 7.9 W and a repetition rate of 10 kHz, the pulse width and the pulse energy of the Q-switch envelope and the average peak power of the QML green laser are 50 ns, 20.34 µJ and 15.5 kW, respectively, corresponding to a pulse width compression of 77%, a pulse energy improvement factor of six times and a QML peak power increase factor of 16 times when compared with those for the solely passively QML green laser. The experimental results show that the dual-loss modulation is an efficient method for the generation of a stable QML green laser with an SWCNT-SA

  10. Micromagnetic simulations of 200-nm-diameter cobalt nanorings using a Reuleaux triangular geometry

    International Nuclear Information System (INIS)

    Torres-Heredia, J.J.; Lopez-Urias, F.; Munoz-Sandoval, E.

    2006-01-01

    Using micromagnetic simulations, we investigated the magnetic states and switching processes of Co nanorings with lateral dimensions of 200 nm. We propose a special geometry of nanorings that adopts different Reuleaux triangular shapes. Reuleaux's triangles (RT) combine both the equilateral triangle and circular geometries. We studied the magnetic spin configurations of individual nanorings by varying the thickness and geometry of the nanomagnets. Our results demonstrated that in most nanomagnets exhibiting a thickness of less than 4 nm, there exists an onion-type state, which precedes either a twisted, double twisted, or cardioid state, when studying the magnetization reversal process. The hysteresis loops and magnetic states found in these RTs are compared with circular nanorings

  11. Phase-shifted Bragg grating inscription in PMMA microstructured POF using 248 nm UV radiation

    DEFF Research Database (Denmark)

    Pereira, L.; Pospori, A.; Antunes, Paulo

    2017-01-01

    In this work we experimentally validate and characterize the first phase-shifted polymer optical fiber Bragg gratings (PS-POFBGs) produced using a single pulse from a 248 nm krypton fluoride laser. A single-mode poly (methyl methacrylate) optical fiber with a core doped with benzyl dimethyl ketal...... for photosensitivity improvement was used. A uniform phase mask customized for 850 nm grating inscription was used to inscribe these Bragg structures. The phase shift defect was created directly during the grating inscription process by placing a narrow blocking aperture in the center of the UV beam. The produced high......-quality Bragg grating structures, presenting a double dips, reject 16.3 dB (97.6% reflectivity) and 13.2 dB (95.2% reflectivity) of the transmitted power, being therefore appropriate for sensing or other photonic applications. Its transmission spectrum possesses two sharp transmission notches, allowing...

  12. High-Frequency Nanocapacitor Arrays: Concept, Recent Developments, and Outlook.

    Science.gov (United States)

    Lemay, Serge G; Laborde, Cecilia; Renault, Christophe; Cossettini, Andrea; Selmi, Luca; Widdershoven, Frans P

    2016-10-18

    We have developed a measurement platform for performing high-frequency AC detection at nanoelectrodes. The system consists of 65 536 electrodes (diameter 180 nm) arranged in a sub-micrometer rectangular array. The electrodes are actuated at frequencies up to 50 MHz, and the resulting AC current response at each separately addressable electrode is measured in real time. These capabilities are made possible by fabricating the electrodes on a complementary metal-oxide-semiconductor (CMOS) chip together with the associated control and readout electronics, thus minimizing parasitic capacitance and maximizing the signal-to-noise ratio. This combination of features offers several advantages for a broad range of experiments. First, in contrast to alternative CMOS-based electrical systems based on field-effect detection, high-frequency operation is sensitive beyond the electrical double layer and can probe entities at a range of micrometers in electrolytes with high ionic strength such as water at physiological salt concentrations. Far from being limited to single- or few-channel recordings like conventional electrochemical impedance spectroscopy, the massively parallel design of the array permits electrically imaging micrometer-scale entities with each electrode serving as a separate pixel. This allows observation of complex kinetics in heterogeneous environments, for example, the motion of living cells on the surface of the array. This imaging aspect is further strengthened by the ability to distinguish between analyte species based on the sign and magnitude of their AC response. Finally, we show here that sensitivity down to the attofarad level combined with the small electrode size permits detection of individual 28 nm diameter particles as they land on the sensor surface. Interestingly, using finite-element methods, it is also possible to calculate accurately the full three-dimensional electric field and current distributions during operation at the level of the

  13. The Effect of Q-Switched Nd:YAG 1064 nm/532 nm Laser in the Treatment of Onychomycosis In Vivo

    Directory of Open Access Journals (Sweden)

    Kostas Kalokasidis

    2013-01-01

    Full Text Available In this prospective clinical study, the Q-Switched Nd:YAG 1064 nm/532 nm laser (Light Age, Inc., Somerset, NJ, USA was used on 131 onychomycosis subjects (94 females, 37 males; ages 18 to 68 years. Mycotic cultures were taken and fungus types were detected. The laser protocol included two sessions with a one-month interval. Treatment duration was approximately 15 minutes per session and patients were observed over a 3-month time period. Laser fluencies of 14 J/cm2 were applied at 9 billionths of a second pulse duration and at 5 Hz frequency. Follow-up was performed at 3 months with mycological cultures. Before and after digital photographs were taken. Adverse effects were recorded and all participants completed “self-evaluation questionnaires” rating their level of satisfaction. All subjects were well satisfied with the treatments, there were no noticeable side effects, and no significant differences were found treating men versus women. At the 3-month follow-up 95.42% of the patients were laboratory mycologically cured of fungal infection. This clinical study demonstrates that fungal nail infections can be effectively and safely treated with Q-Switched Nd:YAG 1064 nm/532 nm laser. It can also be combined with systemic oral antifungals providing more limited treatment time.

  14. ATLAS ITk short-strip stave prototypes with 130 nm chipset

    CERN Document Server

    AUTHOR|(INSPIRE)INSPIRE-00116199; The ATLAS collaboration; Dopke, Jens; Sawyer, Craig

    2017-01-01

    The ATLAS ITk Collaboration is working to deliver a new Inner Tracking detector for use at HL-LHC. The strip tracker community has recently constructed a partially loaded, double-sided demonstrator stave using the HCC / ABC130 chipset in 130 nm CMOS technology. Mindful of the need to maximise power efficiency whilst minimising the cost and material of associated cable plant, the system design includes the integration of a low-mass DC-DC converter and sensor bias (HV) switch within each module. This paper documents the first results from the demonstrator stave. The system concept is also outlined.

  15. ATLAS ITk Short-Strip Stave prototypes with 130nm chipset

    CERN Document Server

    Phillips, Peter William; The ATLAS collaboration

    2017-01-01

    The ATLAS ITk is working to deliver a new Inner Tracking detector for use at HL-LHC. The strip tracker community has recently constructed partially loaded, double sided demonstrator staves using the HCC / ABC130 chipset in 130nm CMOS technology. Mindful of the need to maximise power efficiency whilst minimising the cost and material of associated cable plant, the system design includes the integration of a low-mass DC-DC converter and sensor bias (HV) switch within each module. This paper documents the first results from the demonstrator staves. The system concept and the roadmap toward a full system test are also outlined.

  16. Ultraviolet 320 nm laser excitation for flow cytometry.

    Science.gov (United States)

    Telford, William; Stickland, Lynn; Koschorreck, Marco

    2017-04-01

    Although multiple lasers and high-dimensional analysis capability are now standard on advanced flow cytometers, ultraviolet (UV) lasers (usually 325-365 nm) remain an uncommon excitation source for cytometry. This is primarily due to their cost, and the small number of applications that require this wavelength. The development of the Brilliant Ultraviolet (BUV fluorochromes, however, has increased the importance of this formerly niche excitation wavelength. Historically, UV excitation was usually provided by water-cooled argon- and krypton-ion lasers. Modern flow cytometers primary rely on diode pumped solid state lasers emitting at 355 nm. While useful for all UV-excited applications, DPSS UV lasers are still large by modern solid state laser standards, and remain very expensive. Smaller and cheaper near UV laser diodes (NUVLDs) emitting at 375 nm make adequate substitutes for 355 nm sources in many situations, but do not work as well with very short wavelength probes like the fluorescent calcium chelator indo-1. In this study, we evaluate a newly available UV 320 nm laser for flow cytometry. While shorter in wavelength that conventional UV lasers, 320 is close to the 325 nm helium-cadmium wavelength used in the past on early benchtop cytometers. A UV 320 nm laser was found to excite almost all Brilliant Ultraviolet dyes to nearly the same level as 355 nm sources. Both 320 nm and 355 nm sources worked equally well for Hoechst and DyeCycle Violet side population analysis of stem cells in mouse hematopoetic tissue. The shorter wavelength UV source also showed excellent excitation of indo-1, a probe that is not compatible with NUVLD 375 nm sources. In summary, a 320 nm laser module made a suitable substitute for conventional 355 nm sources. This laser technology is available in a smaller form factor than current 355 nm units, making it useful for small cytometers with space constraints. © 2017 International Society for Advancement of Cytometry. © 2017 International

  17. Efficient second harmonic generation of double-end diffusion-bonded Nd:YVO4 self-Raman laser producing 7.9 W yellow light.

    Science.gov (United States)

    Zhu, Haiyong; Duan, Yanmin; Zhang, Ge; Huang, Chenghui; Wei, Yong; Shen, Hongyuan; Zheng, Yiqun; Huang, Lingxiong; Chen, Zhenqiang

    2009-11-23

    A high power and efficient 588 nm yellow light is demonstrated through intracavity frequency doubling of an acousto-optic Q-switched self-frequency Raman laser. A 30-mm-length double-end diffusion-bonded Nd:YVO(4) crystal was utilized for efficient self-Raman laser operation by reducing the thermal effects and increasing the interaction length for the stimulated Raman scattering. A 15-mm-length LBO with non-critical phase matching (theta = 90 degrees, phi = 0 degrees) cut was adopted for efficient second-harmonic generation. The focus position of incident pump light and both the repetition rate and the duty cycle of the Q-switch have been optimized. At a repetition rate of 110 kHz and a duty cycle of 5%, the average power of 588 nm light is up to 7.93 W while the incident pump power is 26.5 W, corresponding to an overall diode-yellow conversion efficiency of 30% and a slope efficiency of 43%.

  18. A radio frequency single-electron transistor based on an InAs/InP heterostructure nanowire.

    Science.gov (United States)

    Nilsson, Henrik A; Duty, Tim; Abay, Simon; Wilson, Chris; Wagner, Jakob B; Thelander, Claes; Delsing, Per; Samuelson, Lars

    2008-03-01

    We demonstrate radio frequency single-electron transistors fabricated from epitaxially grown InAs/InP heterostructure nanowires. Two sets of double-barrier wires with different barrier thicknesses were grown. The wires were suspended 15 nm above a metal gate electrode. Electrical measurements on a high-resistance nanowire showed regularly spaced Coulomb oscillations at a gate voltage from -0.5 to at least 1.8 V. The charge sensitivity was measured to 32 microe rms Hz(-1/2) at 1.5 K. A low-resistance single-electron transistor showed regularly spaced oscillations only in a small gate-voltage region just before carrier depletion. This device had a charge sensitivity of 2.5 microe rms Hz(-1/2). At low frequencies this device showed a typical 1/f noise behavior, with a level extrapolated to 300 microe rms Hz(-1/2) at 10 Hz.

  19. Relationship between shelf-life and optical properties of Yuanhuang pear in the region of 400-1150 nm

    Science.gov (United States)

    He, Xueming; Fu, Xiaping; Rao, Xiuqin; Fang, Zhenhuan

    2016-05-01

    The main goals of this study are to investigate the potential of absorption coefficient for the prediction of water contents in `Yuanhuang' pear and analyze the relationship between the shelf-life and bulk optical properties in the range of 900-1050 nm. An automated integrating sphere (AIS) system was used to measure the total reflectance, total transmittance of pear flesh tissues in visible-Near infrared (Vis-NIR) range. These two measurements were used to estimate the absorption coefficient μa and reduced scattering coefficient μ's of pear samples by using an inverse adding doubling (IAD) light propagation model. The detection accuracy of the AIS system was verified by using both liquid (Intralipid-20% as scatterer) and solid phantom (TiO2 as scatterer, carbon black as absorber). The relative error of measurement of μ's of liquid phantom with four different concentration (0.5%,1%,1.5%,2%) at 632.8 nm, 751 nm, 833 nm are less than 10% except for 2% concentration at 833 nm, and the relative error of measurement μa and μ's of solid phantom at 525.4 nm, 632.1 nm, 710.3 nm and 780.1 nm are less than 5% except for the μa at 525.4 nm. A total of 140 samples were used to conduct the moisture measurement, and drying method was used. Predictive models for moisture content from μa data were constructed using partial least squares regression (PLSR). The coefficient of correlation of calibration set (Rc) and validation set (Rp) were 0.50 and 0.45 respectively. The relationship between the shelf-life and optical properties was analyzed by dividing pear samples into three categories according to the actual shelf-life, and calculating classification accuracy by using actual and calculated shelf-life grade.

  20. On-chip measurements of Brownian relaxation vs. concentration of 40nm magnetic beads

    DEFF Research Database (Denmark)

    Østerberg, Frederik Westergaard; Rizzi, Giovanni; Hansen, Mikkel Fougt

    2012-01-01

    We present on-chip Brownian relaxation measurements on a logarithmic dilution series of 40 nm beads dispersed in water with bead concentrations between 16 mu g/ml and 4000 mu g/ml. The measurements are performed using a planar Hall effect bridge sensor at frequencies up to 1 MHz. No external fields...... are needed as the beads are magnetized by the field generated by the applied sensor bias current. We show that the Brownian relaxation frequency can be extracted from fitting the Cole-Cole model to measurements for bead concentrations of 64 mu g/ml or higher and that the measured dynamic magnetic response...

  1. Chirp and temperature effects in parametric down conversion from crystals pumped at 800 nm

    Science.gov (United States)

    Sánchez-Lozano, X.; Wiechers, C.; Lucio, J. L.

    2018-04-01

    We consider spontaneous parametric down conversion from aperiodic poled crystals pumped at 800 nm. Our analyses account the effect of internal and external parameters, where, in the former, we include the crystal chirp and length, while in the latter temperature, also the pump chirp and other beam properties. The typical distribution produced is a pop-tab like structure in frequency-momentum space, and our results show that this system is a versatile light source, appropriated to manipulate the frequency and transverse momentum properties of the light produced. We briefly comment on the potential usefulness of the types of telecom wavelength light produced, in particular for quantum information applications.

  2. Elaboration of optical glass-ceramic for frequency doubling

    International Nuclear Information System (INIS)

    Vigouroux, H.

    2012-01-01

    The High power laser development required the need of materials with nonlinear properties. Glass materials can be considered as ideal materials as they can be transparent and elaborated in very large dimension. Precipitation of non-centro symmetric crystalline particles in bulk glass leads to a material with bulk nonlinear properties. This glass-ceramic should be then easily integrated in such laser facilities. In this thesis, the results concerning the precipitation of the phase LiNbO 3 in the glassy-matrix 35 Li 2 O - 25 Nb 2 O 5 - 40 SiO 2 are detailed. The crystallization mechanism of this phase is studied through thermal analysis, optical and electronic microscopy as well as in-situ analyses. These studies reveal glass-ceramics are obtained through a precipitation of the lithium niobate crystalline phase in spherulite shape. The nonlinear optical properties are investigated on this materials and an original, isotropic Second Harmonic Generation Signal (SHG) is registered in the bulk glass-ceramic. A complete study using a multi-scale approach allows the correlation between the spherulite structure and the nonlinear optical properties. A mechanism at the origin of the SHG signal is proposed. This leads to a new approach for transparent inorganic materials development for isotropic SHG conversion. (author) [fr

  3. Nonlinear-optical frequency-doubling metareflector: pulsed regime

    Science.gov (United States)

    Popov, A. K.; Myslivets, S. A.

    2016-01-01

    The properties of backward-wave second-harmonic metareflector operating in pulse regime are investigated. It is made of metamaterial which enables phase matching of contra-propagating fundamental and second-harmonic waves. References are given to the works that prove such a possibility. Physical principles underlying differences in the proposed and standard settings as well as between continuous-wave and pulsed regimes are discussed. Pulsed regime is more practicable and has a broader scope of applications. A set of partial differential equations which describe such a reflector with the account for losses are solved numerically. It is shown that unlike second-harmonic generation in standard settings, contra-propagating pulse of second harmonic may become much longer than the incident fundamental one and the difference grows with decrease in the input pulse length as compared to thickness of the metaslab. The revealed properties are important for applications and may manifest themselves beyond the optical wavelength range.

  4. Amplified, frequency swept lasers for frequency domain reflectometry and OCT imaging: design and scaling principles.

    Science.gov (United States)

    Huber, R; Wojtkowski, M; Taira, K; Fujimoto, J; Hsu, K

    2005-05-02

    We demonstrate a high-speed, frequency swept, 1300 nm laser source for frequency domain reflectometry and OCT with Fourier domain/swept-source detection. The laser uses a fiber coupled, semiconductor amplifier and a tunable fiber Fabry-Perot filter. We present scaling principles which predict the maximum frequency sweep speed and trade offs in output power, noise and instantaneous linewidth performance. The use of an amplification stage for increasing output power and for spectral shaping is discussed in detail. The laser generates ~45 mW instantaneous peak power at 20 kHz sweep rates with a tuning range of ~120 nm full width. In frequency domain reflectometry and OCT applications the frequency swept laser achieves 108 dB sensitivity and ~10 mum axial resolution in tissue. We also present a fast algorithm for real time calibration of the fringe signal to equally spaced sampling in frequency for high speed OCT image preview.

  5. Helium-neon laser stabilized by saturated absorption in iodine at 612 nm.

    Science.gov (United States)

    Cérez, P; Bennett, S J

    1979-04-01

    Hyperfine structure of iodine has been studied at 612 nm by the technique of saturated absorption in an iodine cell placed in a He-Ne laser modified to operate at this wavelength. The most interesting feature of the laser is the existence of strong inverted Lamb dips at a very low vapor pressure, which provides very good short term frequency stability. Some factors which limit the reproducibility of the device are also investigated.

  6. Suppression of high-order-harmonic intensities observed in aligned CO2 molecules with 1300-nm and 800-nm pulses

    International Nuclear Information System (INIS)

    Kato, Kosaku; Minemoto, Shinichirou; Sakai, Hirofumi

    2011-01-01

    High-order-harmonic generation from aligned N 2 , O 2 , and CO 2 molecules is investigated by 1300-nm and 800-nm pulses. The harmonic intensities of 1300-nm pulses from aligned molecules show harmonic photon energy dependence similar to those of 800-nm pulses. Suppression of harmonic intensity from aligned CO 2 molecules is observed for both 1300- and 800-nm pulses over the same harmonic photon energy range. As the dominant mechanism for the harmonic intensity suppression from aligned CO 2 molecules, the present results support the two-center interference picture rather than the dynamical interference picture.

  7. Treatment of pigmentary disorders in patients with skin of color with a novel 755 nm picosecond, Q-switched ruby, and Q-switched Nd:YAG nanosecond lasers: A retrospective photographic review.

    Science.gov (United States)

    Levin, Melissa Kanchanapoomi; Ng, Elise; Bae, Yoon-Soo Cindy; Brauer, Jeremy A; Geronemus, Roy G

    2016-02-01

    Laser procedures in skin of color (SOC) patients are challenging due to the increased risk of dyspigmentation and scarring. A novel 755 nm alexandrite picosecond laser has demonstrated effectiveness for tattoo removal and treatment of acne scars. No studies to date have evaluated its applications in pigmentary disorders. The purpose of this retrospective study was to evaluate the safety profile and efficacy of the picosecond alexandrite laser compared to the current standard treatment, Q-switched ruby and neodynium (Nd):YAG nanosecond lasers, for pigmentary disorders in SOC patients. A retrospective photographic and chart evaluation of seventy 755 nm alexandrite picosecond, ninety-two Q-switched frequency doubled 532 nm and 1,064 nm Nd:YAG nanosecond, and forty-seven Q-switched 694 nm ruby nanosecond laser treatments, in forty-two subjects of Fitzpatrick skin types III-VI was conducted in a single laser specialty center. The picosecond laser was a research prototype device. Treatment efficacy was assessed by two blinded physician evaluators, using a visual analog scale for percentage of pigmentary clearance in standard photographs. Subject assessment of efficacy, satisfaction, and adverse events was performed using a questionnaire survey. The most common pigmentary disorder treated was Nevus of Ota (38.1%), followed by solar lentigines (23.8%). Other pigmentary disorders included post-inflammatory hyperpigmentation, congenital nevus, café au lait macule, dermal melanocytosis, Nevus of Ito, and Becker's nevus. Clinical efficacy of the Q-switched nanosecond lasers and picosecond laser treatments were comparable for lesions treated on the face with a mean visual analog score of 2.57 and 2.44, respectively, corresponding to approximately 50% pigmentary clearance. Subject questionnaires were completed in 58.8% of the picosecond subjects and 52.0% of the Q-switched subjects. Eighty four percent of subjects receiving Q-switched nanosecond laser treatments and 50% of the

  8. High erbium-doped ASE source using optical circulator and fiber loop mirror based on the double-pass double-stage configuration

    Science.gov (United States)

    Lee, Xiang-tao; Wan, Sheng-peng; Shen, Hong-rong

    2007-11-01

    Based on the double-pass double-stage configuration, a better high erbium-doped (4000ppm) amplified spontaneous emission (ASE) configuration with an optical circulator and two (fiber loop mirror) FLMs first used together is experimentally presented, which provides us a output power of more than 0.79dBm and a 3dB line width of 85.3 nm ranging form 1526.017nm to 1611.317nm with the max-wave ripple reduced to 0.4dBm after 1530nm. A simulated profile flattened to 0.4dB is gained from Optisystem 3.0, where we even get a bandwidth of 110nm while the output power reach 3.5dBm

  9. Neutrinoless double beta decay

    Indian Academy of Sciences (India)

    Abstract. The physics potential of neutrinoless double beta decay is discussed. Furthermore, experimental considerations as well as the current status of experiments are presented. Finally, an outlook towards the future, work on nuclear matrix elements and alternative processes is given.

  10. Reflection Positive Doubles

    OpenAIRE

    Jaffe, Arthur; Janssens, Bas

    2016-01-01

    Here we introduce reflection positive doubles, a general framework for reflection positivity, covering a wide variety of systems in statistical physics and quantum field theory. These systems may be bosonic, fermionic, or parafermionic in nature. Within the framework of reflection positive doubles, we give necessary and sufficient conditions for reflection positivity. We use a reflection-invariant cone to implement our construction. Our characterization allows for a direct interpretation in t...

  11. A double layer review

    International Nuclear Information System (INIS)

    Block, L.P.

    1977-06-01

    A review of the main results on electrostatic double layers (sometimes called space charge layers or sheaths) obtained from theory, and laboratory and space experiments up to the spring of 1977 is given. By means of barium jets and satellite probes, double layers have now been found at the altitudes, earlier predicted theoretically. The general potential distribution above the auroral zone, suggested by inverted V-events and electric field reversals, is corroborated. (author)

  12. Raman probes based on optically-poled double-clad fiber and coupler

    DEFF Research Database (Denmark)

    Brunetti, Anna Chiara; Margulis, Walter; Rottwitt, Karsten

    2012-01-01

    Two fiber Raman probes are presented, one based on an optically-poled double-clad fiber and the second based on an optically-poled double-clad fiber coupler respectively. Optical poling of the core of the fiber allows for the generation of enough 532nm light to perform Raman spectroscopy...... of a sample of dimethyl sulfoxide (DMSO), when illuminating the waveguide with 1064nm laser light. The Raman signal is collected in the inner cladding, from which it is retrieved with either a bulk dichroic mirror or a double-clad fiber coupler. The coupler allows for a substantial reduction of the fiber...

  13. Investigations of a Dual Seeded 1178 nm Raman Laser System

    Science.gov (United States)

    2016-01-14

    FBGs, spectrally. A failure to build significant 1121 nm intracavity power in shorter resonator cavities has driven the need to use longer...it results in a maximum amplification of 1178 nm. Although, more power builds in the resonator cavity defined by 5 nm FBGs, because a significant...ES) 8. PERFORMING ORGANIZATION REPORT NUMBER *Leidos, Inc 11951 Freedom Drive Reston, VA 20190 **University of New Mexico ECE Building , Room 125

  14. Antifungal effect of 405-nm light on Botrytis cinerea.

    Science.gov (United States)

    Imada, K; Tanaka, S; Ibaraki, Y; Yoshimura, K; Ito, S

    2014-12-01

    There is very little information on the fungistatic or fungicidal effect of visible light. This study investigated the effect of 405-nm light, generated by a light-emitting diode array, on the economically important fungus Botrytis cinerea. The mycelial growth of B. cinerea was inhibited to the greatest extent by light at 405 and 415 nm and was negligibly inactivated at 450 nm, suggesting the presence of a photosensitizing compound that absorbs light mainly at wavelengths of 405-415 nm. Delta-aminolevulinic acid, a precursor of endogenous photosensitizer porphyrins, was used to determine the role of these porphyrins in 405-nm light-mediated photoinactivation of the fungus. Concentration-dependent inhibition of spore germination by delta-aminolevulinic acid and accumulation of singlet oxygen in the spores was observed when the spores were exposed to 405-nm light. These results suggest that the excitation of endogenous porphyrins and subsequent accumulation of singlet oxygen could partially explain the 405-nm light-mediated photoinactivation of B. cinerea. The development of symptoms in detached tomato leaves inoculated with B. cinerea spores was significantly reduced by irradiation with 405-nm light, indicating that 405-nm light has a potential use for controlling plant diseases caused by B. cinerea. Grey mould (Botrytis cinerea) is a very successful necrotroph, causing serious losses in more than 200 crop hosts. This study investigated the antifungal effect of 405-nm light on this pathogen. Our results suggest that the excitation of endogenous porphyrins and subsequent accumulation of singlet oxygen contribute to the 405-nm light-mediated photoinactivation of grey mould. The development of symptoms in detached tomato leaves inoculated with B. cinerea spores was significantly inhibited by irradiation with 405-nm light, indicating that this wavelength of light has a potential use in controlling plant diseases caused by B. cinerea. © 2014 The Society for

  15. Detection limits of 405 nm and 633 nm excited PpIX fluorescence for brain tumor detection during stereotactic biopsy

    Science.gov (United States)

    Markwardt, Niklas; Götz, Marcus; Haj-Hosseini, Neda; Hollnburger, Bastian; Sroka, Ronald; Stepp, Herbert; Zelenkov, Petr; Rühm, Adrian

    2016-04-01

    5-aminolevulinic-acid-(5-ALA)-induced protoporphyrin IX (PpIX) fluorescence may be used to improve stereotactic brain tumor biopsies. In this study, the sensitivity of PpIX-based tumor detection has been investigated for two potential excitation wavelengths (405 nm, 633 nm). Using a 200 μm fiber in contact with semi-infinite optical phantoms containing ink and Lipovenös, PpIX detection limits of 4.0 nM and 200 nM (relating to 1 mW excitation power) were determined for 405 nm and 633 nm excitation, respectively. Hence, typical PpIX concentrations in glioblastomas of a few μM should be well detectable with both wavelengths. Additionally, blood layers of selected thicknesses were placed between fiber and phantom. Red excitation was shown to be considerably less affected by blood interference: A 50 μm blood layer, for instance, blocked the 405- nm-excited fluorescence completely, but reduced the 633-nm-excited signal by less than 50%. Ray tracing simulations demonstrated that - without blood layer - the sensitivity advantage of 405 nm rises for decreasing fluorescent volume from 50-fold to a maximum of 100-fold. However, at a tumor volume of 1 mm3, which is a typical biopsy sample size, the 633-nm-excited fluorescence signal is only reduced by about 10%. Further simulations revealed that with increasing fiber-tumor distance, the signal drops faster for 405 nm. This reduces the risk of detecting tumor tissue outside the needle's coverage, but diminishes the overlap between optically and mechanically sampled volumes. While 405 nm generally offers a higher sensitivity, 633 nm is more sensitive to distant tumors and considerably superior in case of blood-covered tumor tissue.

  16. Assessing the therapeutic effect of 625-nm light-emitting diodes

    Science.gov (United States)

    Mao, Zongzhen; Xu, Guodong; Yang, Yi

    2014-09-01

    To evaluate the effects of red Light-Emitting Diodes on elbow extensor and flexor strength and the recovery of exercise induced fatigue, the torque values from the isokinetic dynamometer as well as biochemistry parameters were used as outcome measures. A randomized double-blind placebo-controlled crossover trial was performed with twenty male young tennis athletes. Active LED therapy (LEDT, with wavelength 625nm, 10 minutes total irradiation time, irradiated area amount to 30cm2, and 900J of total energy irradiated) or an identical placebo was delivered under double-blinded conditions to the left elbow just before exercise. The isokinetic muscle strength was measured immediately after irradiation. The blood lactate levels were sampled pre-exercise and post-exercise. The peak torque values of elbow extensor strength were significantly different between two groups. As in elbow flexor strength, the difference of peak torque was not significant. The blood lactate concentration of LEDT group post-exercise was significantly lower than those of placebo group. The results indicate that 625nm LED therapy is effective in preventing muscle fatigue as it can significantly reduce peak torque value of elbow extensors and blood lactate concentration. It has no effect on the strength of left elbow flexor or backhand performance in tennis.

  17. Iodine frequency references for space

    International Nuclear Information System (INIS)

    Schuldt, Thilo; Braxmaier, Claus; Döringshoff, Klaus; Peters, Achim; Oswald, Markus; Johann, Ulrich

    2017-01-01

    Optical frequency references are a key element for the realization of future space missions. They are needed for missions related to tests of fundamental physics, gravitational wave detection, Earth observation and navigation and ranging. In missions such as GRACE follow-on or LISA the optical frequency reference is used as light source for high-sensitivity inter-satellite distance metrology. While cavity-based systems are current baseline e.g. for LISA, frequency stabilization on a hyperfine transition in molecular iodine near 532 nm is a promising alternative. Due to its absolute frequency, iodine standards crucially simplify the initial spacecraft acquisition procedures. Current setups fulfill the GRACE-FO and LISA frequency stability requirements and are realized near Engineering Model level. We present the current status of our developments on Elegant Breadboard (EBB) and Engineering Model (EM) level taking into account specific design criteria for space compatibility such as compactness (size iodine spectroscopy EM: 38 × 18 × 10 cm 3 ) and robustness. Both setups achieved similar frequency stabilities of ∼ 1 · 10 −14 at an integration time of 1 s and below 5 · 10 −15 at integration times between 10 s and 1000 s. Furthermore, we present an even more compact design currently developed for a sounding rocket mission with launch in 2017. (paper)

  18. Iodine frequency references for space

    Science.gov (United States)

    Schuldt, Thilo; Döringshoff, Klaus; Oswald, Markus; Johann, Ulrich; Peters, Achim; Braxmaier, Claus

    2017-05-01

    Optical frequency references are a key element for the realization of future space missions. They are needed for missions related to tests of fundamental physics, gravitational wave detection, Earth observation and navigation and ranging. In missions such as GRACE follow-on or LISA the optical frequency reference is used as light source for high-sensitivity inter-satellite distance metrology. While cavity-based systems are current baseline e.g. for LISA, frequency stabilization on a hyperfine transition in molecular iodine near 532 nm is a promising alternative. Due to its absolute frequency, iodine standards crucially simplify the initial spacecraft acquisition procedures. Current setups fulfill the GRACE-FO and LISA frequency stability requirements and are realized near Engineering Model level. We present the current status of our developments on Elegant Breadboard (EBB) and Engineering Model (EM) level taking into account specific design criteria for space compatibility such as compactness (size iodine spectroscopy EM: 38 × 18 × 10 cm3) and robustness. Both setups achieved similar frequency stabilities of ˜ 1 · 10-14 at an integration time of 1 s and below 5 · 10-15 at integration times between 10 s and 1000 s. Furthermore, we present an even more compact design currently developed for a sounding rocket mission with launch in 2017.

  19. Double-pumped multiwavelength fiber optical parametric oscillator based on a Sagnac loop filter.

    Science.gov (United States)

    Sun, Bing; Hu, Kai; Wei, Yizhen; Chen, Daru; Gao, Shiming; Wang, Tianshu; He, Sailing

    2012-01-01

    We propose a double-pumped ring cavity multiwavelength fiber optical parametric oscillator (MW-FOPO) using a highly nonlinear dispersion-shifted fiber (HNL-DSF) as the gain medium and a polarization maintained fiber based Sagnac loop filter as the comblike filter. 22-wavelength lasing of the double-pumped MW-FOPO with a ripple less than ±2.5 dB and a wavelength spacing of about 0.8 nm in a wavelength range from 1541 nm to 1558 nm is experimentally demonstrated. We discussed the power stability of the multiwavelength lasing of the double-pumped MW-FOPO. A comparison of the output spectra between the double-pumped MW-FOPO and single-pumped MW-FOPO is also presented. © 2012 Optical Society of America

  20. Strain and deformations engineered germanene bilayer double gate-field effect transistor by first principles

    Science.gov (United States)

    Meher Abhinav, E.; Chandrasekaran, Gopalakrishnan; Kasmir Raja, S. V.

    2017-10-01

    Germanene, silicene, stanene, phosphorene and graphene are some of single atomic materials with novel properties. In this paper, we explored bilayer germanene-based Double Gate-Field Effect Transistor (DG-FET) with various strains and deformations using Density Functional Theory (DFT) and Green's approach by first-principle calculations. The DG-FET of 1.6 nm width, 6 nm channel length (Lch) and HfO2 as gate dielectric has been modeled. For intrinsic deformation of germanene bilayer, we have enforced minute mechanical deformation of wrap and twist (5°) and ripple (0.5 Å) on germanene bilayer channel material. By using NEGF formalism, I-V Characteristics of various strains and deformation tailored DG-FET was calculated. Our results show that rough edge and single vacancy (5-9) in bilayer germanene diminishes the current around 47% and 58% respectively as compared with pristine bilayer germanene. In case of strain tailored bilayer DG-FET, multiple NDR regions were observed which can be utilized in building stable multiple logic states in digital circuits and high frequency oscillators using negative resistive techniques.

  1. A Faraday laser lasing on Rb 1529 nm transition.

    Science.gov (United States)

    Chang, Pengyuan; Peng, Huanfa; Zhang, Shengnan; Chen, Zhangyuan; Luo, Bin; Chen, Jingbiao; Guo, Hong

    2017-08-21

    We present the design and performance characterization of a Faraday laser directly lasing on the Rb 1529 nm transition (Rb, 5P 3/2  - 4D 5/2 ) with high stability, narrow spectral linewidth and low cost. This system does not need an additional frequency-stabilized pump laser as a prerequisite to preparing Rb atom from 5S to 5P excited state. Just by using a performance-improved electrodeless discharge lamp-based excited-state Faraday anomalous dispersion optical filter (LESFADOF), we realized a heterogeneously Faraday laser with the frequency corresponding to atomic transition, working stably over a range of laser diode (LD) current from 85 mA to 171 mA and the LD temperature from 11 °C to 32 °C, as well as the 24-hour long-term frequency fluctuation range of no more than 600 MHz. Both the laser linewidth and relative intensity noisy (RIN) are measured. The Faraday laser lasing on Rb 1529 nm transition (telecom C-band) can be applied to further research on metrology, microwave photonics and optical communication systems. Besides, since the transitions correspongding to the populated excited-states of alkali atoms within lamp are extraordinarily rich, this scheme can increase the flexibility for choosing proper wavelengths for Faraday laser and greatly expand the coverage of wavelength corresponding to atomic transmission for laser frequency stabilization.

  2. Single frequency narrow linewidth 2 micron laser, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — NASA needs narrow linewidth lasers in the 1.5 or 2 micron wavelength regime for coherent Lidar applications. The laser should be tunable by several nm and frequency...

  3. Evaluation of dental pulp repair using low level laser therapy (688 nm and 785 nm) morphologic study in capuchin monkeys

    International Nuclear Information System (INIS)

    Pretel, H; Ramalho, L T O; Oliveira, J A; Lizarelli, R F Z

    2009-01-01

    The aim of this study was to evaluate the hypothesis that low-level laser therapy (LLLT) 688 nm and 785 nm accelerate dentin barrier formation and repair process after traumatic pulp exposure. The sample consisted of 45 premolars of capuchin monkeys (Cebus apella) with pulp exposure Class V cavities. All premolars were treated with calcium hydroxide (Ca(OH) 2 ), divided in groups of 15 teeth each, and analyzed on 7 th , 25 th , and 60 th day. Group GI – only Ca(OH) 2 , GII – laser 688 nm, and GIII – laser 785 nm. Laser beam was used in single and punctual dose with the parameters: continuous, 688 nm and 785 nm wavelength, tip's area of 0.00785 cm 2 , power 50 mW, application time 20 s, dose 255 J/cm 2 , energy 2 J. Teeth were capped with Ca(OH) 2 , Ca(OH) 2 cement and restored with amalgam. All groups presented pulp repair. On 25 th day the thickness of the formed dentin barrier was different between the groups GI and GII (p th day there was difference between GI and GIII (p < 0.01). It may be concluded that, LLLT 688 nm and 785 nm accelerated dentin barrier formation and consequently pulp repair process, with best results using infrared laser 785 nm

  4. Evaluation of dental pulp repair using low level laser therapy (688 nm and 785 nm) morphologic study in capuchin monkeys

    Science.gov (United States)

    Pretel, H.; Oliveira, J. A.; Lizarelli, R. F. Z.; Ramalho, L. T. O.

    2009-02-01

    The aim of this study was to evaluate the hypothesis that low-level laser therapy (LLLT) 688 nm and 785 nm accelerate dentin barrier formation and repair process after traumatic pulp exposure. The sample consisted of 45 premolars of capuchin monkeys (Cebus apella) with pulp exposure Class V cavities. All premolars were treated with calcium hydroxide (Ca(OH)2), divided in groups of 15 teeth each, and analyzed on 7th, 25th, and 60th day. Group GI - only Ca(OH)2, GII - laser 688 nm, and GIII - laser 785 nm. Laser beam was used in single and punctual dose with the parameters: continuous, 688 nm and 785 nm wavelength, tip's area of 0.00785 cm2, power 50 mW, application time 20 s, dose 255 J/cm2, energy 2 J. Teeth were capped with Ca(OH)2, Ca(OH)2 cement and restored with amalgam. All groups presented pulp repair. On 25th day the thickness of the formed dentin barrier was different between the groups GI and GII (p < 0.05) and between groups GI and GIII (p < 0.01). On 60th day there was difference between GI and GIII (p < 0.01). It may be concluded that, LLLT 688 nm and 785 nm accelerated dentin barrier formation and consequently pulp repair process, with best results using infrared laser 785 nm.

  5. On high speed transmission with the 850 nm VCSELs

    DEFF Research Database (Denmark)

    Turkiewicz, Jarosław P.; Chorchos, Łukasz; Puerta Ramírez, Rafael

    2016-01-01

    One of the key research challenges is development of energy efficient high bit rate data interconnects. The most promising solutions are based on 850 nm vertical cavity surface emitting lasers (VCSEL) and multi mode fibre (MMF). In this paper options to realize energy efficient 850 nm data interc...

  6. A photonic crystal fiber with zero dispersion at 1064 nm

    DEFF Research Database (Denmark)

    Andersen, Peter Andreas

    2002-01-01

    We report on the dispersion properties of a single mode, large core photonic crystal fiber. Using white light interferometry the fiber is found to have zero dispersion at 1064 nm......We report on the dispersion properties of a single mode, large core photonic crystal fiber. Using white light interferometry the fiber is found to have zero dispersion at 1064 nm...

  7. Electron beam inspection of 16nm HP node EUV masks

    Science.gov (United States)

    Shimomura, Takeya; Narukawa, Shogo; Abe, Tsukasa; Takikawa, Tadahiko; Hayashi, Naoya; Wang, Fei; Ma, Long; Lin, Chia-Wen; Zhao, Yan; Kuan, Chiyan; Jau, Jack

    2012-11-01

    EUV lithography (EUVL) is the most promising solution for 16nm HP node semiconductor device manufacturing and beyond. The fabrication of defect free EUV mask is one of the most challenging roadblocks to insert EUVL into high volume manufacturing (HVM). To fabricate and assure the defect free EUV masks, electron beam inspection (EBI) tool will be likely the necessary tool since optical mask inspection systems using 193nm and 199nm light are reaching a practical resolution limit around 16nm HP node EUV mask. For production use of EBI, several challenges and potential issues are expected. Firstly, required defect detection sensitivity is quite high. According to ITRS roadmap updated in 2011, the smallest defect size needed to detect is about 18nm for 15nm NAND Flash HP node EUV mask. Secondly, small pixel size is likely required to obtain the high sensitivity. Thus, it might damage Ru capped Mo/Si multilayer due to accumulated high density electron beam bombardments. It also has potential of elevation of nuisance defects and reduction of throughput. These challenges must be solved before inserting EBI system into EUV mask HVM line. In this paper, we share our initial inspection results for 16nm HP node EUV mask (64nm HP absorber pattern on the EUV mask) using an EBI system eXplore® 5400 developed by Hermes Microvision, Inc. (HMI). In particularly, defect detection sensitivity, inspectability and damage to EUV mask were assessed. As conclusions, we found that the EBI system has capability to capture 16nm defects on 64nm absorber pattern EUV mask, satisfying the sensitivity requirement of 15nm NAND Flash HP node EUV mask. Furthermore, we confirmed there is no significant damage to susceptible Ru capped Mo/Si multilayer. We also identified that low throughput and high nuisance defect rate are critical challenges needed to address for the 16nm HP node EUV mask inspection. The high nuisance defect rate could be generated by poor LWR and stitching errors during EB writing

  8. Project Half Double

    DEFF Research Database (Denmark)

    Svejvig, Per; Ehlers, Michael; Adland, Karoline Thorp

    and as an opportunity rather than a threat and a risk. We are convinced that by doing so, we can strengthen Denmark’s competitiveness and play an important role in the battle for jobs and future welfare. The overall goal is to deliver “projects in half the time with double the impact”, where projects in half the time...... many of the key performance indicators associated with them can be evaluated (Grundfos and Siemens Wind Power). In addition to the current status of delivering impact faster for the seven pilot projects, it is important to highlight that Project Half Double phase 1 has planted many seeds in the pilot......Project Half Double has a clear mission to succeed in finding a project methodology that can increase the success rate of our projects while increasing the speed at which we generate new ideas and develop new products and services. Chaos and complexity should be seen as a basic condition...

  9. Cobalt double-ring and double-dot structures: Magnetic properties

    International Nuclear Information System (INIS)

    López-Urías, F.; Torres-Heredia, J.J.; Muñoz-Sandoval, E.

    2016-01-01

    The magnetization reversal mechanism of nanostructures of cobalt double-rings (D-rings) and double-dots (D-dots) is investigated in the framework of micromagnetic simulations. The arrays contain two identical coupled rings (wide and narrow) or dots with outer diameter of 200 nm and thicknesses ranging from 2–20 nm. Hysteresis loops, dipole–dipole and exchange energies are systematically calculated for the cases of the structures touching and the structures with a 50-nm inter-magnet separation; moreover, magnetization states along the hysteresis curve are analyzed. The results of both dot and ring D-magnets are compared with the corresponding individual magnets. Our results reveal that all D-ring (in contact and separated) arrays containing narrow rings exhibit non-null remanent magnetization; furthermore, higher coercive fields are promoted when the magnet thickness is increased. It is observed that the magnetization reversal is driven mainly by a clockwise rotation of onion-states, followed by states of frustrated vortices. Our results could help improve the understanding of the magnetic interactions in nanomagnet arrays.

  10. Cobalt double-ring and double-dot structures: Magnetic properties

    Energy Technology Data Exchange (ETDEWEB)

    López-Urías, F., E-mail: flo@ipicyt.edu.mx [Advanced Materials Department, IPICYT, Camino a la presa San José 2055, Col. Lomas 4a sección, 78216, San Luis Potosí S.L.P., México (Mexico); Torres-Heredia, J.J. [Instituto Tecnológico Superior de Las Choapas, Col. J. M. Rosa do, 96980, Las Choapas, Veracruz (Mexico); Muñoz-Sandoval, E. [Advanced Materials Department, IPICYT, Camino a la presa San José 2055, Col. Lomas 4a sección, 78216, San Luis Potosí S.L.P., México (Mexico)

    2016-02-15

    The magnetization reversal mechanism of nanostructures of cobalt double-rings (D-rings) and double-dots (D-dots) is investigated in the framework of micromagnetic simulations. The arrays contain two identical coupled rings (wide and narrow) or dots with outer diameter of 200 nm and thicknesses ranging from 2–20 nm. Hysteresis loops, dipole–dipole and exchange energies are systematically calculated for the cases of the structures touching and the structures with a 50-nm inter-magnet separation; moreover, magnetization states along the hysteresis curve are analyzed. The results of both dot and ring D-magnets are compared with the corresponding individual magnets. Our results reveal that all D-ring (in contact and separated) arrays containing narrow rings exhibit non-null remanent magnetization; furthermore, higher coercive fields are promoted when the magnet thickness is increased. It is observed that the magnetization reversal is driven mainly by a clockwise rotation of onion-states, followed by states of frustrated vortices. Our results could help improve the understanding of the magnetic interactions in nanomagnet arrays.

  11. Thin film and multilayer optics for XUV spectral domain (1 nm to 60 nm)

    International Nuclear Information System (INIS)

    Delmotte, Franck

    2010-02-01

    The XUV spectral domain (1-60 nm wavelength range) has experienced rapid growth in recent years. On one side, the sources (synchrotron radiation, harmonic generation, x-ray laser, free-electron laser...) require ever more efficient optics, on the other hand, applications (diagnostics of hot plasma, solar physics, x-ray microscopy, EUV lithography, x-ray analysis...) provide new constraints on the design of multilayer stacks. The multilayer mirrors are the only way to achieve efficient optics operating at non-grazing incidence angles in this spectral range. Our work within the team XUV Optics at Laboratoire Charles Fabry de l'Institut d'Optique focuses on the study of materials in thin layers correlated to the study of optical properties of multilayers. The objective is to achieve new multilayer components previously unavailable in the XUV domain, through a better understanding of physical phenomena in these nano-layer stacks. We show through several examples of how we have managed both to improve the performance of multilayer mirrors in a broad spectral range, and secondly, to develop new optical functions: beam splitters, broadband mirrors, dual-band mirrors or phase compensation mirrors. (author)

  12. Penetration of nanoparticles in 5 nm to 400 nm size range through two selected fibrous media

    International Nuclear Information System (INIS)

    Brochot, C; Michielsen, N; Mouret, G; Thomas, D; Chazelet, S

    2011-01-01

    Due to the strong development of nanotechnologies, ultrafine particles could represent a growing hazard for workers health. When it is not possible to reduce the risk at its source, filtration systems are one of the means used to limit the exposure to hazardous substances such as airborne particles. The aim of this study is to measure the penetration of nanoparticles on a very large diameter range, from the nanometer size to the most penetrating particle size (MPPS). Here we present experimental results obtained for three different types of nanoparticles. Measurements of nanoparticle penetration through two low efficiency fiberglass media are carried out using two test benches presented in this article. Penetration values for carbon, copper and NaCl nanoparticles decreases with particle size, as predicted by theory. The value of the most penetrating particle size is situated between 100 and 300 nm. No thermal rebound was observed in this particle size range. The penetration values will be used, in further studies, to determine a global penetration model.

  13. Picosecond laser texturization of mc-silicon for photovoltaics: A comparison between 1064 nm, 532 nm and 355 nm radiation wavelengths

    Energy Technology Data Exchange (ETDEWEB)

    Binetti, Simona [Department of Materials Science and Milano-Bicocca Solar Energy Research Center (MIB-SOLAR), University of Milano-Bicocca, Via Cozzi 55, 20125 Milano (Italy); Le Donne, Alessia, E-mail: alessia.ledonne@mater.unimib.it [Department of Materials Science and Milano-Bicocca Solar Energy Research Center (MIB-SOLAR), University of Milano-Bicocca, Via Cozzi 55, 20125 Milano (Italy); Rolfi, Andrea [Department of Materials Science and Milano-Bicocca Solar Energy Research Center (MIB-SOLAR), University of Milano-Bicocca, Via Cozzi 55, 20125 Milano (Italy); Jäggi, Beat; Neuenschwander, Beat [Bern University of Applied Sciences, Engineering and Information Technology, Institute for Applied Laser, Photonics and Surface Technologies ALPS, Pestalozzistrasse 20, CH-3400 Burgdorf (Switzerland); Busto, Chiara [ENI Spa, Via Giacomo Fauser, 4, 28100 Novara (Italy); Frigeri, Cesare [CNR-IMEM Institute, Parco Area Delle Scienze 37/A, Fontanini, 43010 Parma (Italy); Scorticati, Davide; Longoni, Luca; Pellegrino, Sergio [Laserpoint Srl, Via Della Burrona 51, 20090 Vimodrone, Milano (Italy)

    2016-05-15

    Highlights: • Self-organized surface structures were produced by picosecond laser pulses on mc-Si. • Three laser wavelengths were used which effectively reduce Si reflectivity up to 8%. • The subsurface damage induced by the three lasers was studied in detail. • μ-Raman, PL and TEM proved that UV laser provides the lowest subsurface damage. • UV laser induced damage is located above the depletion region of the p–n junction. - Abstract: Self-organized surface structures were produced by picosecond laser pulses on multi-crystalline silicon for photovoltaic applications. Three different laser wavelengths were employed (i.e. 1064 nm, 532 nm and 355 nm) and the resulting morphologies were observed to effectively reduce the reflectivity of the samples after laser irradiation. Besides, a comparative study of the laser induced subsurface damage generated by the three different wavelengths was performed by confocal micro-Raman, photoluminescence and transmission electron microscopy. The results of both the structural and optical characterization showed that the mc-Si texturing performed with the laser at 355 nm provides surface reflectivity between 11% and 8% over the spectral range from 400 nm to 1 μm, while inducing the lowest subsurface damage, located above the depletion region of the p–n junction.

  14. Double Chooz experiment

    International Nuclear Information System (INIS)

    Palomares, C.

    2009-01-01

    Double Chooz will use two identical detectors at different distances from the Chooz nuclear power station to search for a non-vanishing value of θ 13 , and, hopefully, to open the way to experiments aspiring to discover CP violation in the leptonic sector. The far detector is expected to be operative by the end of 2009. Installation of the near detector will occur in 2010. Double Chooz has the capacity to exclude sin 2 (2θ 13 ) 31 2 = 2.5 x 10 -3 eV 2 with three years of data running both near and far detectors. (author)

  15. John Deakin: Double Exposures

    Directory of Open Access Journals (Sweden)

    Paul Rousseau

    2015-11-01

    Full Text Available In this series of short films made by Jonathan Law, the art historian James Boaden, and the curator of The John Deakin Archive, Paul Rousseau, discuss the double-exposure images made by the photographer John Deakin (1912-1972 in the 1950s and 1960s. The films ask you, firstly, to look closely at the images being discussed. Each one begins with a sustained and intense shot of a single image before opening up to a wide-ranging discussion about Deakin, double exposures, and photography.

  16. Tunable Narrow Linewidth, Low Noise 2.05 Micron Single Frequency Seeder Laser, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose an all-fiber based 2.05-micron single frequency, narrow linewidth seeder laser with 10 nm tuning range and 5GHz frequency modulation for next generation...

  17. Tunable Narrow Linewidth, Low Noise 2.05 Micron Single Frequency Seeder Laser, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose an all-fiber based 2.05-micron single frequency, narrow linewidth seeder laser with 10 nm tuning range and 5GHz frequency modulation for next generation...

  18. Sensitive detection and separation of fluorescent derivatives using capillary electrophoresis with laser-induced fluorescence detection with 532nm Nd:YAG laser

    International Nuclear Information System (INIS)

    Vrabel, Patrik; Taborsky, Petr; Ryvolova, Marketa; Havel, Josef; Preisler, Jan

    2006-01-01

    Capillary electrophoresis with laser-induced fluorescence detection (CELIF) is a powerful tool for separation and sensitive determination of fluorescent species. Biologically active compounds, such as amino acids, peptides and proteins may exhibit native fluorescence, which is however often low and/or an expensive laser is required for excitation in UV. Therefore, labelling of the analytes with a fluorescent dye is usually necessary. In this work, a home-built CELIF instrument with diode pumped frequency-doubled continuous wave Nd:YAG excitation laser with feedback power regulation (532nm) was constructed. The suitability of this type of laser for LIF detection in a separation method was found excellent. A limit of detection (LOD) (S/N=3) of 2x10 -13 mol/l was achieved with rhodamine B, which is comparable to those obtained using similar instruments with Ar + laser [Y.F. Cheng, N.J. Dovichi, Science 242 (1988) 562, E.S. Yeung et al., J. Chromatogr. 608 (1992) 73]. LOD of a protein derivatized according to modified procedures [M.J. Little et al., Anal. Chim. Acta 339 (1997) 279, A. Chersi et al., Biochim. Biophys. Acta 1336 (1997) 83] was determined. Detection of the derivatives was found to be limited by insufficient reaction recovery at low analyte concentration, chemical noise, separation efficiency and quality of the derivatizing reagent rather than by the detector performance. As a consequence, a huge gap between the detection ability of CELIF instruments and LOD determined in real samples is revealed

  19. Development of 2-channel (532 nm and 355 nm) mobile LIDAR for mapping particulate matter in the atmosphere

    CSIR Research Space (South Africa)

    Sivakumar, V

    2010-09-01

    Full Text Available In this paper, the authors describe the developmentof 2-Channel (532 nm and 355 nm) mobile LIDAR system for studying atmospheric particulate matter. The system is currently tested in house at the Council for Scientific and Industrial Research...

  20. Spin wave eigenmodes in single and coupled sub-150 nm rectangular permalloy dots

    Energy Technology Data Exchange (ETDEWEB)

    Carlotti, G., E-mail: giovanni.carlotti@fisica.unipg.it; Madami, M. [Dipartimento di Fisica e Geologia, Università di Perugia, Perugia (Italy); Tacchi, S. [Istituto Officina dei Materiali del CNR (CNR-IOM), Dipartimento di Fisica e Geologia, Perugia (Italy); Gubbiotti, G.; Dey, H.; Csaba, G.; Porod, W. [Center for Nano Science and Technology, Department of Electrical Engineering, University of Notre Dame, Notre Dame, Indiana 46556 (United States)

    2015-05-07

    We present the results of a Brillouin light scattering investigation of thermally excited spin wave eigenmodes in square arrays of either isolated rectangular dots of permalloy or twins of dipolarly coupled elements, placed side-by-side or head-to-tail. The nanodots, fabricated by e-beam lithography and lift-off, are 20 nm thick and have the major size D in the range between 90 nm and 150 nm. The experimental spectra show the presence of two main peaks, corresponding to modes localized either at the edges or in the center of the dots. Their frequency dependence on the dot size and on the interaction with adjacent elements has been measured and successfully interpreted on the basis of dynamical micromagnetic simulations. The latter enabled us also to describe the spatial profile of the eigenmodes, putting in evidence the effects induced by the dipolar interaction between coupled dots. In particular, in twinned dots the demagnetizing field is appreciably modified in proximity of the “internal edges” if compared to the “external” ones, leading to a splitting of the edge mode. These results can be relevant for the exploitation of sub-150 nm magnetic dots in new applications, such as magnonic metamaterials, bit-patterned storage media, and nano-magnetic logic devices.

  1. Sequential double photodetachment of He- in elliptically polarized laser fields

    Science.gov (United States)

    Génévriez, Matthieu; Dunseath, Kevin M.; Terao-Dunseath, Mariko; Urbain, Xavier

    2018-02-01

    Four-photon double detachment of the helium negative ion is investigated experimentally and theoretically for photon energies where the transient helium atom is in the 1 s 2 s 3S or 1 s 2 p P3o states, which subsequently ionize by absorption of three photons. Ionization is enhanced by intermediate resonances, giving rise to series of peaks in the He+ spectrum, which we study in detail. The He+ yield is measured in the wavelength ranges from 530 to 560 nm and from 685 to 730 nm and for various polarizations of the laser light. Double detachment is treated theoretically as a sequential process, within the framework of R -matrix theory for the first step and effective Hamiltonian theory for the second step. Experimental conditions are accurately modeled, and the measured and simulated yields are in good qualitative and, in some cases, quantitative agreement. Resonances in the double detachment spectra can be attributed to well-defined Rydberg states of the transient atom. The double detachment yield exhibits a strong dependence on the laser polarization which can be related to the magnetic quantum number of the intermediate atomic state. We also investigate the possibility of nonsequential double detachment with a two-color experiment but observe no evidence for it.

  2. Endovenous simulated laser experiments at 940 nm and 1470 nm suggest wavelength-independent temperature profiles.

    Science.gov (United States)

    van den Bos, R R; van Ruijven, P W M; van der Geld, C W M; van Gemert, M J C; Neumann, H A M; Nijsten, T

    2012-07-01

    EVLA has proven to be very successful, but the optimum methods for energy delivery have still not been clarified. A better understanding of the mechanism of action may contribute to achieving a consensus on the best laser method and the most effective use of laser parameters, resulting in optimal clinical outcomes, maintaining high success rates with minimal adverse events. The aim of this study is to assess the impact of wavelength, pullback speed and power level on the endovenous temperature profile in an experimental setting. In an experimental setting, temperature measurements were performed using thermocouples. The experimental set-up consisted of a transparent box in which a glass tube was fixed. Different laser parameters (wavelength and power) and 2 different pullback speeds (2 and 5 mm/s) were used. Thermocouples were placed at different distances from the fiber tip. Validity of the experimental setting was assessed by performing the same temperature measurements using a stripped varicose vein. The maximal temperature rise and the time span that the temperature was above collagen denaturation temperature were measured. The experiments showed that decreasing the pullback speed (2 mm/s) and increasing the power (up to 14 W) both cause higher maximal temperature and a longer time above the temperature for collagen denaturation. The use of different laser wavelengths (940 or 1470 nm) did not influence the temperature profile. The results of our experiments show that wavelength on its own has not been demonstrated to be an important parameter to influence the temperature profile. Copyright © 2012 European Society for Vascular Surgery. Published by Elsevier Ltd. All rights reserved.

  3. Layered double hydroxides

    DEFF Research Database (Denmark)

    López Rayo, Sandra; Imran, Ahmad; Hansen, Hans Chr. Bruun

    2017-01-01

    A novel zinc (Zn) fertilizer concept based on Zn doped layered double hydroxides (Zn-doped Mg-Fe-LDHs) has been investigated. Zn-doped Mg-Fe-LDHs were synthetized, their chemical composition was analyzed and their nutrient release was studied in buffered solutions with different pH values. Uptake...

  4. Beyond the double banana

    DEFF Research Database (Denmark)

    Rosenzweig, Ivana; Fogarasi, András; Johnsen, Birger

    2014-01-01

    performance was compared with the double banana (longitudinal bipolar montage, 10-20 array). RESULTS: Adding the inferior temporal electrode chain, computed montages (reference free, common average, and source derivation), and voltage maps significantly increased the sensitivity. Phase maps had the highest...

  5. Double aortic arch

    Science.gov (United States)

    Surgery can be done to fix double aortic arch. The surgeon ties off the smaller branch and separates it from the larger branch. Then the surgeon closes the ends of the aorta with stitches. This relieves pressure on the esophagus and windpipe.

  6. Aristotle and Double Effect

    DEFF Research Database (Denmark)

    Di Nucci, Ezio

    2014-01-01

    cases from the literature on double effect such as, amongst others, strategic bombing, the trolley problem, and craniotomy. I find that, despite some common features such as the dilemmatic structure and the inevitability of a bad effect, Aristotle’s mixed actions do not count as cases justifiable...

  7. Nuclear double beta decay

    International Nuclear Information System (INIS)

    Hubert, P.; Mennrath, P.

    1985-01-01

    The processes of double beta decay with and without emission of neutrinos are briefly reviewed. After the definitions of the processes and implications for the neutrino properties, the present status of the experimental results is discussed. We conclude with a description of the Bordeaux-Zaragoza-Strasbourg experimental which will run in the Frejus tunnel

  8. Design for Double Rainbow

    Science.gov (United States)

    Thomas, Lisa Carlucci

    2011-01-01

    Rare is the inspirational, spontaneous, transformative moment shared among 20 million people. In the summer of 2010, people around the world were moved by the sighting of a double rainbow--almost a triple rainbow--"all the way across the sky" in Yosemite National Park. Caught on video and posted to by YouTube by Paul Vasquez in January 2010, the…

  9. Aristotle and Double Effect

    DEFF Research Database (Denmark)

    Di Nucci, Ezio

    2014-01-01

    There are some interesting similarities between Aristotle’s ‘mixed actions’ in Book III of the Nicomachean Ethics and the actions often thought to be justifiable with the Doctrine of Double Effect. Here I analyse these similarities by comparing Aristotle’s examples of mixed actions with standard ...

  10. Double-grating polychromator for laser-aided plasma diagnostics

    International Nuclear Information System (INIS)

    Mukhin, E.E.; Razdobarin, G.T.; Semenov, V.V.; Shilnikov, A.N.; Sukhanov, V.L.; Tolstjakov, S.Yu.; Kochergin, M.M.; Mihailovskij, Yu.K.; Bakh, L.I.

    2004-01-01

    A wide bandpass double-grating polychromator with high rejection and high transmission has been designed and manufactured for laser-aided plasma diagnostics. The special mount utilizes subtractive dispersion in the second stage of the double polychromator such that the larger dispersion of the second stage is reduced by that of the first stage. This affects the intensity of the stray light background at the laser wavelength. The background at the edge of the laser line was measured at 10 -5 of the light incident on the input slit. At the short end of the 200 nm bandpass, the stray light relative intensity approached 10 -7

  11. Tapered diode laser pumped 946 nm Nd:YAG laser

    DEFF Research Database (Denmark)

    Cheng, Haynes Pak Hay; Jensen, Ole Bjarlin; Petersen, Paul Michael

    2009-01-01

    We successfully implemented a 946 nm Nd:YAG laser based on a 808 nm tapered diode pump laser. The tapered diode is developed at the Ferdinand-Braun-Institute fur Hochstfrequenztechnik in Germany. Figure 2 shows the experimental setup and results of each pump source coupled into a 1.5 mm crystal...... laser, we show that tapered diode laser pumping potentially increase the power of 946 nm lasers by a factor of two and reduce the threshold by a factor of three....

  12. Mandrel-based patterning: density multiplication techniques for 15nm nodes

    Science.gov (United States)

    Bencher, Chris; Dai, Huixiong; Miao, Liyan; Chen, Yongmei; Xu, Ping; Chen, Yijian; Oemardani, Shiany; Sweis, Jason; Wiaux, Vincent; Hermans, Jan; Chang, Li-Wen; Bao, Xinyu; Yi, He; Wong, H.-S. Philip

    2011-04-01

    In many ways, sidewall spacer double patterning has created a new paradigm for lithographic roadmaps. Instead of using lithography as the principal process for generating device features, the role of lithography becomes to generate a mandrel (a pre-pattern) off-of-which one will subsequently replicate patterns with various degrees of density multiplication. Under this new paradigm, the innovativeness of various density multiplication techniques is as critical to the scaling roadmap as the exposure tools themselves. Sidewall spacer double patterning was the first incarnation of mandrel based patterning; adopted quickly in NAND flash where layouts were simple and design space was focused. But today, the use of advanced automated decomposition tools are showing spacer based patterning solutions for very complex logic designs. Future incarnations can involve the use of laminated spacers to create quadruple patterning or by retaining the original mandrel as a method to obtain triple patterning. Directed self-assembly is yet another emerging embodiment of mandrel based patterning, where selfseparating polymers are registered and guided by the physical constraint of a mandrel or by chemical pre-pattern trails formed onto the substrate. In this summary of several bodies of work, we will review several wafer level demonstrations, all of which use various forms of mandrel or stencil based density multiplication including sidewall spacer based double, triple and quadruple patterning techniques for lines, SADP for via multiplication, and some directed self-assembly results all capable of addressing 15nm technology node requirements and below. To address concerns surrounding spacer double patterning design restrictions, we show collaboration results with an EDA partner to demonstrate SADP capability for BEOL routing layers. To show the ultimate realization of SADP, we partner with IMEC on multiple demonstrations of EUV+SADP.

  13. Direct initiation of the photopolymerization of acrylates by 222 nm excimer UV radiation

    International Nuclear Information System (INIS)

    Knolle, W.; Scherzer, T.; Naumov, S.; Mehnert, R.

    2002-01-01

    Complete text of publication follows. Usually, the photopolymerisation of functionalised monomers and oligomers requires the addition of one or several photoinitiators to the formulation. The light of typically used mercury lamps (1>250 nm) is mainly absorbed by the photoinitiator leading to initiating species (radicals) with a high quantum yield. The introduction of excimer lamps as monochromatic UV sources with an intense short-wavelength emission opens up new possibilities for a photoinitiator-free initiation of the acrylate polymerisation. Like most other organic compounds, acrylates strongly absorb light with a wavelength shorter than about 220 to 240 nm, and they can therefore be directly excited by the 222 nm excimer radiation from a KrCl* lamp. Real-time FTIR-ATR spectroscopy was used to study the reactivity of various neat acrylates. Depending on the absorption coefficient, aliphatic acrylates can be cured up to a thickness of several microns whereas for highly absorbing aromatic acrylates, the depth of cure reaches only some hundred nanometres. Since the radical yield is low, photopolymerisation without photoinitiator has to be performed in an inert atmosphere. Laser photolysis experiments were carried out with a KrCl* excimer laser (pulse width 20 ns, up to 5 mJ per pulse) to investigate the primary processes of the direct initiation. Additionally, quantum chemical calculations were performed to assist the interpretation of the photolysis data. For all acrylates studied, direct excitation at 222 nm first leads to the formation of a triplet state which is highly localized at the vinyl double bond (and not at the carbonyl group). This triplet state may undergo different reactions like inter- and intramolecular hydrogen transfer and biradical formation as well as the addition to a ground state molecule (chain start). Our current interpretation of the experimental results and the quantum chemical calculations will be presented and discussed

  14. 300 mW of coherent light at 488 nm using a generic approach

    DEFF Research Database (Denmark)

    Karamehmedovic, Emir; Pedersen, Christian; Andersen, Martin Thalbitzer

    2008-01-01

    We present a generic approach for efficient generation of CW light with a predetermined wavelength within the visible or UV spectrum. Based on sum-frequency generation (SFG), the circulating intra-cavity field of a high-finesse diode pumped CW solid-state laser (DPSSL) and the output from a tapered...... at 1342 nm. Up to 308 mW of light at 488nm was measured in our experiments. The conversion of the ECDL beam was up to 47% after it was transmitted through a PM fiber, and up to 32% without fiber coupling. Replacing the seed laser and the nonlinear crystal makes it possible to generate light at virtually...... any desired wavelength within the visible spectrum....

  15. BIA Wingate High School WWTF, Fort Wingate, NM: NN0020958

    Science.gov (United States)

    NPDES Permit and Fact Sheet explaining EPA's action under the Clean Water Act to issue NPDES Permit No. NN0020958 to Bureau of Indian Affairs (BIA) Wingate High School Wastewater Treatment Lagoon, Fort Wingate, NM.

  16. Compact 2050 nm Semiconductor Diode Laser Master Oscillator, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — This Phase I effort seeks to develop DFB laser master oscillators at the novel wavelength of 12050 nm. Two prototypes will be built, tested, and delivered ....

  17. Photorefractive effect at 775 nm in doped lithium niobate crystals

    Energy Technology Data Exchange (ETDEWEB)

    Nava, G.; Minzioni, P.; Cristiani, I.; Degiorgio, V. [Department of Electrical, Computer, and Biomedical Engineering, and CNISM, University of Pavia, 27100 Pavia (Italy); Argiolas, N.; Bazzan, M.; Ciampolillo, M. V.; Pozza, G.; Sada, C. [Physics and Astronomy Departement, University of Padova, 35131 Padova (Italy)

    2013-07-15

    The photorefractive effect induced by 775-nm laser light on doped lithium niobate crystals is investigated by the direct observation in the far field of the transmitted-beam distortion as a function of time. Measurements performed at various Zr-doping concentrations and different light intensities show that the 775-nm light beam induces a steady-state photorefractive effect comparable to that of 532-nm light, but the observed build-up time of the photovoltaic field is longer by three-orders of magnitude. The 775-nm photorefractivity of lithium niobate crystals doped with 3 mol. % ZrO{sub 2} or with 5.5 mol. % MgO is found to be negligible.

  18. Variation of the Mn I 539.4 nm line with the solar cycle

    Science.gov (United States)

    Danilovic, S.; Solanki, S. K.; Livingston, W.; Krivova, N.; Vince, I.

    2016-03-01

    Context. As a part of the long-term program at Kitt Peak National Observatory (KPNO), the Mn I 539.4 nm line has been observed for nearly three solar cycles using the McMath telescope and the 13.5 m spectrograph in double-pass mode. These full-disk spectrophotometric observations revealed an unusually strong change of this line's parameters over the solar cycle. Aims: Optical pumping by the Mg II k line was originally proposed to explain these variations. More recent studies have proposed that this is not required and that the magnetic variability (I.e., the changes in solar atmospheric structure due to faculae) might explain these changes. Magnetic variability is also the mechanism that drives the changes in total solar irradiance variations (TSI). With this work we investigate this proposition quantitatively by using the same model that was earlier successfully employed to reconstruct the irradiance. Methods: We reconstructed the changes in the line parameters using the model SATIRE-S, which takes only variations of the daily surface distribution of the magnetic field into account. We applied exactly the same model atmospheres and value of the free parameter as were used in previous solar irradiance reconstructions to now model the variation in the Mn I 539.4 nm line profile and in neighboring Fe I lines. We compared the results of the theoretical model with KPNO observations. Results: The changes in the Mn I 539.4 nm line and a neighbouring Fe I 539.52 nm line over approximately three solar cycles are reproduced well by the model without additionally tweaking the model parameters, if changes made to the instrument setup are taken into account. The model slightly overestimates the change for the strong Fe I 539.32 nm line. Conclusions: Our result confirms that optical pumping of the Mn II 539.4 nm line by Mg II k is not the main cause of its solar cycle change. It also provides independent confirmation of solar irradiance models which are based on the assumption

  19. Cascaded Soliton Compression of Energetic Femtosecond Pulses at 1030 nm

    DEFF Research Database (Denmark)

    Bache, Morten; Zhou, Binbin

    2012-01-01

    We discuss soliton compression with cascaded second-harmonic generation of energetic femtosecond pulses at 1030 nm. We discuss problems encountered with soliton compression of long pulses and show that sub-10 fs compressed pulses can be achieved.......We discuss soliton compression with cascaded second-harmonic generation of energetic femtosecond pulses at 1030 nm. We discuss problems encountered with soliton compression of long pulses and show that sub-10 fs compressed pulses can be achieved....

  20. Biostimulation using an 810nm Diode Laser - A Case Series

    Directory of Open Access Journals (Sweden)

    Naseem Joy Garg

    2013-01-01

    Full Text Available A decrease in orthodontic treatment time is not only a demand by the esthetically concerned patient but is also the duty of every orthodontist. With the advent of 810 nm diode laser it could be made possible. This article presents a case series wherein use of 810 nm has been used to biostimulate the tissues and thereby resulting in increased rate of tooth movement appreciated by amount of clinically detected space closure.

  1. Investigation of a Pulsed 1550 nm Fiber Laser System

    Science.gov (United States)

    2015-12-15

    The pulses then encounter an amplified spontaneous emission (ASE) filter which blocks any power outside of the passband which is approximately 1 nm...the ASE filter will not absorb light in the passband around 1550 nm that lies between the pulses. Also, after the second stage and beyond, an EOM...amplifier stage. An electro-optic modulator as well as amplified spontaneous emission filters were used to enable pulses with high contrast relative to

  2. A chip-scale, telecommunications-band frequency conversion interface for quantum emitters.

    Science.gov (United States)

    Agha, Imad; Ates, Serkan; Davanço, Marcelo; Srinivasan, Kartik

    2013-09-09

    We describe a chip-scale, telecommunications-band frequency conversion interface designed for low-noise operation at wavelengths desirable for common single photon emitters. Four-wave-mixing Bragg scattering in silicon nitride waveguides is used to demonstrate frequency upconversion and downconversion between the 980 nm and 1550 nm wavelength regions, with signal-to-background levels > 10 and conversion efficiency of ≈ -60 dB at low continuous wave input pump powers ( 25 % in existing geometries. Finally, we present waveguide designs that can be used to connect shorter wavelength (637 nm to 852 nm) quantum emitters with 1550 nm.

  3. Comparison of Molecular Iodine Spectral Properties at 514.7 and 532 nm Wavelengths

    Czech Academy of Sciences Publication Activity Database

    Hrabina, Jan; Acef, O.; Du Burck, F.; Chiodo, N.; Candela, Y.; Šarbort, Martin; Holá, Miroslava; Lazar, Josef

    2014-01-01

    Roč. 14, č. 4 (2014), s. 213-218 ISSN 1335-8871 R&D Projects: GA ČR GPP102/11/P820; GA MŠk(CZ) LO1212; GA MŠk ED0017/01/01; GA MŠk EE2.4.31.0016; GA TA ČR TA02010711; GA TA ČR TA01010995; GA TA ČR TE01020233 Institutional support: RVO:68081731 Keywords : laser spectroscopy * metrology * molecular iodine * absorption cells * frequency doubling * nterferometry Subject RIV: BH - Optics, Masers, Lasers Impact factor: 0.989, year: 2014

  4. Observation of Frequency Locked Coherent Transition Radiation

    CERN Document Server

    Marsh, Roark A; Temkin, Richard J

    2005-01-01

    Measurements of frequency locked, coherent transition radiation (CTR) were performed at the 17 GHz high-gradient accelerator facility built by Haimson Research Corporation at MIT PSFC. CTR produced from a metallic foil placed in the beam path was extracted through a window, and measured with a variety of detectors, including: diode, Helium cooled Si Bolometer, and double heterodyne receiver system. The angular energy distribution measured by the diode and bolometer are in agreement and consistent with calculations for a 15 MeV 200 mA 110 ns beam of 1 ps bunches. Heterodyne receiver measurements were able to show frequency locking, namely inter-bunch coherence at integer multiples of the accelerator RF frequency of 17.14 GHz. At the locked frequencies the power levels are enhanced by the number of bunches in a single beam pulse. The CTR was measured as a comb of locked frequencies up to 240 GHz, with a bandwidth of 50 MHz.

  5. Thermal noise in double injection diodes operating in the insulator regime

    NARCIS (Netherlands)

    Zijlstra, R.J.J.; Gisolf, A.

    Thermal noise calculations, based on the Langevin procedure, are given for a double injection diode operating in the insulator regime. The frequency range is restricted to frequencies smaller than the reciprocal free carrier transit times. It turns out that at high frequencies the spectral density

  6. Generation of single-frequency tunable green light in a coupled ring tapered diode laser cavity

    DEFF Research Database (Denmark)

    Jensen, Ole Bjarlin; Petersen, Paul Michael

    2013-01-01

    in the broad wavelength range from 1049 nm to 1093 nm and the beam propagation factor is improved from M2 = 2.8 to below 1.1. The laser frequency is automatically locked to the cavity resonance frequency using optical feedback. Furthermore, we show that this adaptive external cavity approach leads to efficient...

  7. Project Half Double

    DEFF Research Database (Denmark)

    Svejvig, Per; Gerstrøm, Anna; Frederiksen, Signe Hedeboe

    projects and to document their development. The purpose of this addendum is thus to document the development in the pilot projects from June 2016 to January 2017 with particular focus on the impact they have created. This Addendum is a supplement and should be read in conjunction with the Phase 1 report...... by the day. The formal part of Project Half Double was initiated in June 2015; it is divided into two phases where phase 1 took place from June 2015 to June 2016 with seven pilot projects, and phase 2 is in progress from July 2016 to July 2017 with 10 pilot projects. The Half Double consortium: Implement....... The Danish Industry Foundation, an independent philanthropic foundation, is contributing to the project financially with DKK 13.8 million. About the addendum: We published the report “Preliminary results for phase 1” in June 2016 (Svejvig, Ehlers et al. 2016). It is time to follow up on the Phase 1 pilot...

  8. The double Laplacian growth

    International Nuclear Information System (INIS)

    Loutsenko, I.; Yermolayeva, O.

    2008-06-01

    The dynamics of the idealized Laplacian growth (or the Hele-Shaw problem) can be approximated by the Poiselle flow which in appropriate units takes the form of the Darcy law. In this paper we account for the liquid inertia in the Hele-Shaw problem at zero surface tension limit. The Laplace dynamics for the pressure is extended here with one more for the velocity potential for which we call this growth process the Double Laplacian. The application of the conformal mappings technique leads to doubled dynamics for both the conformal map and the complex potential, which is presented in the paper for the radial and the planar growth. We apply the stability analysis and discuss the integrability for the stated problem. (author)

  9. Subatmospheric double containment system

    International Nuclear Information System (INIS)

    Gans, D. Jr.; Noble, J.H.

    1978-01-01

    A reinforced concrete double wall nuclear containment structure with each wall including an essentially impervious membrane or liner and porous concrete filling the annulus between the two walls is described. The interior of the structure is maintained at subatmospheric pressure, and the annulus between the two walls is maintained at a subatmospheric pressure intermediate between that of the interior and the surrounding atmospheric pressure, during normal operation. In the event of an accident within the containment structure the interior pressure may exceed atmospheric pressure, but leakage from the interior to the annulus between the double walls will not result in the pressure of the annulus exceeding atmospheric pressure so that there is no net outleakage from the containment structure

  10. A low-power time-domain VCO-based ADC in 65 nm CMOS

    Science.gov (United States)

    Chenluan, Wang; Shengxi, Diao; Fujiang, Lin

    2014-10-01

    A low-power, high-FoM (figure of merit), time-domain VCO (voltage controlled oscillator)-based ADC (analog-to-digital converter) in 65 nm CMOS technology is proposed. An asynchronous sigma—delta modulator (ASDM) is used to convert the voltage input signal to a square wave time signal, where the information is contained in its pulse-width. A time-domain quantizer, which uses VCO to convert voltage to frequency, is adopted, while the XOR (exclusive-OR) gate circuits convert the frequency information to digital representatives. The ASDM does not need an external clock, so there is no quantization noise. At the same time, the ASDM applies a harmonic-distortion-cancellation technique to its transconductance stage, which increases the SNDR (signal to noise and distortion ratio) performance of the ASDM. Since the output of the ASDM is a two-level voltage signal, the VCO's V—F (voltage to frequency) conversion curve is always linear. The XOR phase quantizer has an inherent feature of first-order noise-shaping. It puts the ADC's low-frequency output noise to high-frequency which is further filtered out by a low-pass filter. The proposed ADC achieves an SNR/SNDR of 54. dB/54.3 dB in the 8 MHz bandwidth, while consuming 2.8 mW. The FoM of the proposed ADC is a 334 fJ/conv-step.

  11. Phonon tunneling through a double barrier system

    Energy Technology Data Exchange (ETDEWEB)

    Villegas, Diosdado [Departamento de Física, Universidad Central “Marta Abreu” de Las Villas, CP 54830, Santa Clara, Villa Clara (Cuba); Instituto de Física, Universidad Autónoma de Puebla, 18 Sur y San Claudio, Edif. 110A, Ciudad Universitaria, 72570 Puebla (Mexico); León-Pérez, Fernando de [Centro Universitario de la Defensa de Zaragoza, Ctra. de Huesca s/n, E-50090 Zaragoza (Spain); Pérez-Álvarez, R. [Universidad Autónoma del Estado de Morelos, Av. Universidad 1001, CP 62209 Cuernavaca (Mexico); Arriaga, J., E-mail: arriaga@ifuap.buap.mx [Instituto de Física, Universidad Autónoma de Puebla, 18 Sur y San Claudio, Edif. 110A, Ciudad Universitaria, 72570 Puebla (Mexico)

    2015-04-15

    The tunneling of optical and acoustic phonons at normal incidence on a double-barrier is studied in this paper. Transmission coefficients and resonance conditions are derived theoretically under the assumption that the long-wavelength approximation is valid. It is shown that the behavior of the transmission coefficients for the symmetric double barrier has a Lorentzian form close to resonant frequencies and that Breit–Wigner's formula have a general validity in one-dimensional phonon tunneling. Authors also study the so-called generalized Hartman effect in the tunneling of long-wavelength phonons and show that this effect is a numerical artifact resulting from taking the opaque limit before exploring the variation with a finite barrier width. This study could be useful for the design of acoustic devices.

  12. Phonon tunneling through a double barrier system

    International Nuclear Information System (INIS)

    Villegas, Diosdado; León-Pérez, Fernando de; Pérez-Álvarez, R.; Arriaga, J.

    2015-01-01

    The tunneling of optical and acoustic phonons at normal incidence on a double-barrier is studied in this paper. Transmission coefficients and resonance conditions are derived theoretically under the assumption that the long-wavelength approximation is valid. It is shown that the behavior of the transmission coefficients for the symmetric double barrier has a Lorentzian form close to resonant frequencies and that Breit–Wigner's formula have a general validity in one-dimensional phonon tunneling. Authors also study the so-called generalized Hartman effect in the tunneling of long-wavelength phonons and show that this effect is a numerical artifact resulting from taking the opaque limit before exploring the variation with a finite barrier width. This study could be useful for the design of acoustic devices

  13. Neutrinoless double beta decay

    Indian Academy of Sciences (India)

    2012-10-06

    Oct 6, 2012 ... nuclear decay of neutrinoless double beta decay typically leading to sub-eV values as well. (Z, A) → (Z + 2, A) + 2e .... Here again energy resolution matters, because of the continuous spectrum of the 2νββ- decay mode, its high .... The benefit of using Te is its high natural abundance. This experiment is in ...

  14. Suspension for the low frequency facility

    CERN Document Server

    Cella, G; Di Virgilio, A; Gaddi, A; Viceré, A

    2000-01-01

    We introduce the working principles of the VIRGO Low Frequency Facility (LFF), whose main aim is the measurement of the thermal noise in the VIRGO suspension system. We evaluate the displacement thermal noise of a mirror, which is an intermediate element of a double pendulum suspension system. This double pendulum will be suspended to the last stage of a VIRGO Super-Attenuator (SA), the prototype VIRGO suspension system being tested at the Pisa section of INFN. In the proposed configuration, we evaluate the spectrum of the thermal noise for different choices of the parameters: based on this study, we comment on the future directions to be undertaken in the LFF experiment.

  15. Frequency noise in frequency swept fiber laser

    DEFF Research Database (Denmark)

    Pedersen, Anders Tegtmeier; Rottwitt, Karsten

    2013-01-01

    This Letter presents a measurement of the spectral content of frequency shifted pulses generated by a lightwave synthesized frequency sweeper. We found that each pulse is shifted in frequency with very high accuracy. We also discovered that noise originating from light leaking through the acousto...

  16. Experimental Studies of Simultaneous 351 nm and 527 nm Laser Beam Interactions in a Long Scalelength Plasma

    International Nuclear Information System (INIS)

    Moody, J D; Divol, L; Glenzer, S H; MacKinnon, A J; Froula, D H; Gregori, G; Kruer, W L; Suter, L J; Williams, E A; Bahr, R; Seka, W

    2003-01-01

    We describe experiments investigating the simultaneous backscattering from 351 nm (3w) and 527 nm (2w) interaction beams in a long scalelength laser-produced plasma for intensities (le) 1 x 10 15 W/cm 2 . Measurements show comparable scattering fractions for both color probe beams. Time resolved spectra of stimulated Raman and Brillouin scattering (SRS and SBS) indicate the effects of laser intensity and smoothing as well as plasma composition and parameters on the scattering levels

  17. Laser frequency stabilization and large detuning by Doppler-free ...

    Indian Academy of Sciences (India)

    We present results of a study of frequency stabilization of a diode laser ( = 780 nm) using the Doppler-free dichroic lock (DFDL) technique and its use for laser cooling of atoms. Quantitative measurements of frequency stability were performed and the Allan variance was found to be 6.9 × 10−11 for an averaging time of 10 ...

  18. Characterization and corrosion behavior of F6NM stainless steel treated in high temperature water

    Science.gov (United States)

    Li, Zheng-yang; Cai, Zhen-bing; Yang, Wen-jin; Shen, Xiao-yao; Xue, Guo-hong; Zhu, Min-hao

    2018-03-01

    F6NM martensitic stainless steel was exposed to 350 °C water condition for 500, 1500, and 2500 h to simulate pressurized water reactor (PWR) condition. The characterization and corrosion behavior of the oxide film were investigated. Results indicate that the exposed steel surface formed a double-layer oxide film. The outer oxide film is Fe-rich and contains two type oxide particles. However, the inner oxide film is Cr-rich, and two oxide films, whose thicknesses increase with increasing exposure time. The oxide film reduces the corrosion behavior because the outer oxide film has many crack and pores. Finally, the mechanism and factors affecting the formation of the oxide film were investigated.

  19. 32nm 1-D regular pitch SRAM bitcell design for interference-assisted lithography

    Science.gov (United States)

    Greenway, Robert T.; Jeong, Kwangok; Kahng, Andrew B.; Park, Chul-Hong; Petersen, John S.

    2008-10-01

    As optical lithography advances into the 45nm technology node and beyond, new manufacturing-aware design requirements have emerged. We address layout design for interference-assisted lithography (IAL), a double exposure method that combines maskless interference lithography (IL) and projection lithography (PL); cf. hybrid optical maskless lithography (HOMA) in [2] and [3]. Since IL can generate dense but regular pitch patterns, a key challenge to deployment of IAL is the conversion of existing designs to regular-linewidth, regular-pitch layouts. In this paper, we propose new 1-D regular pitch SRAM bitcell layouts which are amenable to IAL. We evaluate the feasibility of our bitcell designs via lithography simulations and circuit simulations, and confirm that the proposed bitcells can be successfully printed by IAL and that their electrical characteristics are comparable to those of existing bitcells.

  20. High-Frequency-Induced Cathodic Breakdown during Plasma Electrolytic Oxidation

    Science.gov (United States)

    Nominé, A.; Nominé, A. V.; Braithwaite, N. St. J.; Belmonte, T.; Henrion, G.

    2017-09-01

    The present communication shows the possibility of observing microdischarges under cathodic polarization during plasma electrolytic oxidation at high frequency. Cathodic microdischarges can ignite beyond a threshold frequency found close to 2 kHz. The presence (respectively, absence) of an electrical double layer is put forward to explain how the applied voltage can be screened, which therefore prevents (respectively, promotes) the ignition of a discharge. Interestingly, in the conditions of the present study, the electrical double layer requires between 175 and 260 μ s to form. This situates the expected threshold frequency between 1.92 and 2.86 kHz, which is in good agreement with the value obtained experimentally.

  1. Low Power Digital Clock Design Using LVCMOS Input/Output Standards on 45nm FPGA

    DEFF Research Database (Denmark)

    Pandey, Sujeet; Mehta, Rishabh; Kalia, Kartik

    2016-01-01

    metal oxide semiconductor i.e. LVCMOS and 45nm Spartan-6 FPGA family is used for simulation and amount of total power consumed is noted down. There is 90.02%, 98.88%, 99.86% and 100% reduction in the clock when we scale down frequency from 100GHz to 10GHz, 1GHz, 0.1GHz, and 0.01GHz respectively.......How wonderful it would be if every device we use is energy efficient. This is an approach to design an efficient digital clock that consumes low amount of power. This is done by varying frequency to different levels and checking corresponding amount of energy consumed. Low Voltage Complementary...

  2. Double layers - theory and experiment

    International Nuclear Information System (INIS)

    Torven, S.

    1980-06-01

    A survey is given of recent investigations of electric double layers in low density plasmas. The existence of double layers is now well established in both magnetized and unmagnetized plasmas. Laboratory experiments and numerical simulations show that double layers coexist with waves and fluctuations as expected in view of the particle beams which are formed in the layer. Under certain conditions the level of the fluctuations is small and experimental results then compare favourably with stationary double layer models. Significant progress on layer formation processes has been made, but further investigations are required to predict under what conditions double layers will form in different types of plasmas. (author)

  3. Fluorescence and Raman spectra on surface of K9 glass by high fluence ultraviolet laser irradiation at 355 nm

    Science.gov (United States)

    Zhang, Zhen; Huang, Jin; Geng, Feng; Zhou, Xiaoyan; Feng, Shiquan; Ren, Dahua; Cheng, Xinlu; Jiang, Xiaodong; Wu, Weidong; Zheng, Wanguo; Tang, Yongjian

    2013-11-01

    In order to explore the damage mechanisms of K9 glass irradiated by high energy density ultraviolet laser, laser-induced fluorescence and Raman spectra were investigated. Compared the fluorescence spectra of damaged area, undamaged area and sub-damaged area, it can be conclude that the fluorescence spectrum of sub-damaged area is different from the structure of the other two areas. Especially, the main peak of the spectra at 415 nm reveals the unique characteristics of K9 glass. The structure at the sub-damaged area enhances intensity of the Raman scattering spectra. Three peaks of the spectra at about 500 nm and two characteristic peaks at about 550 nm exhibit the characterization of damaged area. A peak of the Raman scattering spectra at 350 nm which related to water can be observed. The relationship between intensity of Raman scattering and laser intensity at 355 nm is investigated by confocal Raman microscopy. At sub-damage area, signal of Raman scattering is rather high and decreased dramatically with respect to energy density. The major band at about 1470 cm-1 sharpened and moved to higher frequency with densification. These phenomena demonstrate that the structure of sub-damaged area has some characterization compared with the damaged area. The investigation of defect induced fluorescence and Raman spectra on surface of K9 glass is important to explore the damage mechanisms of optical materials irradiated by ultraviolet laser irradiation at 355 nm.

  4. Frequency mixing in boron carbide laser ablation plasmas

    Science.gov (United States)

    Oujja, M.; Benítez-Cañete, A.; Sanz, M.; Lopez-Quintas, I.; Martín, M.; de Nalda, R.; Castillejo, M.

    2015-05-01

    Nonlinear frequency mixing induced by a bichromatic field (1064 nm + 532 nm obtained from a Q-switched Nd:YAG laser) in a boron carbide (B4C) plasma generated through laser ablation under vacuum is explored. A UV beam at the frequency of the fourth harmonic of the fundamental frequency (266 nm) was generated. The dependence of the efficiency of the process as function of the intensities of the driving lasers differs from the expected behavior for four-wave mixing, and point toward a six-wave mixing process. The frequency mixing process was strongly favored for parallel polarizations of the two driving beams. Through spatiotemporal mapping, the conditions for maximum efficiency were found for a significant delay from the ablation event (200 ns), when the medium is expected to be a low-ionized plasma. No late components of the harmonic signal were detected, indicating a largely atomized medium.

  5. Ac-induced disruption of the doubleDs structure in tomato

    NARCIS (Netherlands)

    Rommens, Caius M.T.; Biezen, Erik A. van der; Ouwerkerk, Pieter B.F.; Nijkamp, H. John J.; Hille, Jacques

    1991-01-01

    The maize doubleDs element is stably maintained in the tomato genome. Upon the subsequent introduction of Ac into a plant containing doubleDs, disruption of the doubleDs structure and DNA rearrangements at the site of the doubleDs element were observed. No indications were obtained for excision of

  6. Photodissociation threshold and emission with 220 nm of icy ethene

    Science.gov (United States)

    Lo, Jen-Iu; Chou, Sheng-Lung; Peng, Yu-Chain; Lu, Hsiao-Chi; Cheng, Bing-Ming

    2018-03-01

    The depletion of ethene, C2H4, dispersed in solid neon was measured upon irradiation with ultraviolet light from a synchrotron source. The threshold for the dissociation of solid ethene is wavelength 210 ± 5 nm, corresponding to energy 5.90 ± 0.13 eV. We recorded emission spectra for the transition T → N of ethene dispersed in solid neon, dinitrogen and water, excited at 220 nm; the band origins are 286.5, 289.8 and 290.0 nm, respectively. This investigation of the depletion of icy ethene with UV light enhances our understanding of its photochemistry in astronomical environments. This emission feature of solid ethene can provide a new means of identification for its observation in space.

  7. Low energy proton induced single event upset in 65 nm DDR and QDR commercial SRAMs

    Science.gov (United States)

    Ye, B.; Liu, J.; Wang, T. S.; Liu, T. Q.; Maaz, K.; Luo, J.; Wang, B.; Yin, Y. N.; Ji, Q. G.; Sun, Y. M.; Hou, M. D.

    2017-09-01

    The single event upset (SEU) response of 65 nm commercial double data rate static random access memory (SRAM) and quad data rate SRAM was investigated by using proton beams with energies in the range of 0.15 MeV to 8.0 MeV. Experimental results show that a significant number of SEU occurrences can be triggered when the energy of incident proton is below 1 MeV. For the low energy protons, the SEU cross section measured in these SRAMs was found to increase with increasing proton energy, attaining a peak value, and then decreases as the proton energy was further increased. While in case of quad data rate SRAMs, it seems that they are more sensitive to SEU occurrences as compared with double data rate SRAMs. The bias voltage and data pattern dependence on SEU cross section induced by the low energy protons were also investigated in this work. In addition, the over-layer thickness of the SRAMs and the impact of degrader use in proton induced SEU test were also analyzed in detail. Monte Carlo simulations results indicate that the use of degrader in case of low energy proton induced SEU test results in a significant reduction of the SEU cross section.

  8. Impact response analysis of a coaxial double-pipe structure

    International Nuclear Information System (INIS)

    Nishida, Akemi; Iigaki, Kazuhiko

    2010-01-01

    A coaxial double-pipe structure is to be used in the main primary coolant system of a high-temperature gas-cooled reactor. In order to study the vibration characteristics of a coaxial double-pipe structure, hammering tests were performed on test models of a coaxial double-pipe structure. Because high frequency components were included in the structural responses of this type of tests, impact response analysis was performed by using spectral element that has high precision in the high frequency domain. By the comparison between analysis results and experiment results, it was confirmed that the analytical results had good agreement with the experimental results. Also we performed parametric studies about damping properties of the test models. As a result of having identified the damping properties using experiment results, it was found that inner pipe and outer pipe had different damping properties. In this paper, these results were shown. (author)

  9. 970-nm ridge waveguide diode laser bars for high power DWBC systems

    Science.gov (United States)

    Wilkens, Martin; Erbert, Götz; Wenzel, Hans; Knigge, Andrea; Crump, Paul; Maaßdorf, Andre; Fricke, Jörg; Ressel, Peter; Strohmaier, Stephan; Schmidt, Berthold; Tränkle, Günther

    2018-02-01

    de lasers are key components in material processing laser systems. While mostly used as pump sources for solid state or fiber lasers, direct diode laser systems using dense wavelength multiplexing have come on the market in recent years. These systems are realized with broad area lasers typically, resulting in beam quality inferior to disk or fiber lasers. We will present recent results of highly efficient ridge waveguide (RW) lasers, developed for dense-wavelength-beamcombining (DWBC) laser systems expecting beam qualities comparable to solid state laser systems and higher power conversion efficiencies (PCE). The newly developed RW lasers are based on vertical structures with an extreme double asymmetric large optical cavity. Besides a low vertical divergence these structures are suitable for RW-lasers with (10 μm) broad ridges, emitting in a single mode with a good beam quality. The large stripe width enables a lateral divergence below 10° (95 % power content) and a high PCE by a comparably low series resistance. We present results of single emitters and small test arrays under different external feedback conditions. Single emitters can be tuned from 950 nm to 975 nm and reach 1 W optical power with more than 55 % PCE and a beam quality of M2 < 2 over the full wavelength range. The spectral width is below 30 pm FWHM. 5 emitter arrays were stabilized using the same setup. Up to now we reached 3 W optical power, limited by power supply, with 5 narrow spectral lines.

  10. Q-switched Erbium-doped fiber laser at 1600 nm for photoacoustic imaging application

    Science.gov (United States)

    Piao, Zhonglie; Zeng, Lvming; Chen, Zhongping; Kim, Chang-Seok

    2016-04-01

    We present a nanosecond Q-switched Erbium-doped fiber (EDF) laser system operating at 1600 nm with a tunable repetition rate from 100 kHz to 1 MHz. A compact fiber coupled, acousto-optic modulator-based EDF ring cavity was used to generate a nanosecond seed laser at 1600 nm, and a double-cladding EDF based power amplifier was applied to achieve the maximum average power of 250 mW. In addition, 12 ns laser pulses with the maximum pulse energy of 2.4 μJ were obtained at 100 kHz. Furthermore, the Stokes shift by Raman scattering over a 25 km long fiber was measured, indicating that the laser can be potentially used to generate the high repetition rate pulses at the 1.7 μm region. Finally, we detected the photoacoustic signal from a human hair at 200 kHz repetition rate with a pulse energy of 1.2 μJ, which demonstrates that a Q-switched Er-doped fiber laser can be a promising light source for the high speed functional photoacoustic imaging.

  11. Sub-10-nm intracellular bioelectronic probes from nanowire-nanotube heterostructures.

    Science.gov (United States)

    Fu, Tian-Ming; Duan, Xiaojie; Jiang, Zhe; Dai, Xiaochuan; Xie, Ping; Cheng, Zengguang; Lieber, Charles M

    2014-01-28

    The miniaturization of bioelectronic intracellular probes with a wide dynamic frequency range can open up opportunities to study biological structures inaccessible by existing methods in a minimally invasive manner. Here, we report the design, fabrication, and demonstration of intracellular bioelectronic devices with probe sizes less than 10 nm. The devices are based on a nanowire-nanotube heterostructure in which a nanowire field-effect transistor detector is synthetically integrated with a nanotube cellular probe. Sub-10-nm nanotube probes were realized by a two-step selective etching approach that reduces the diameter of the nanotube free-end while maintaining a larger diameter at the nanowire detector necessary for mechanical strength and electrical sensitivity. Quasi-static water-gate measurements demonstrated selective device response to solution inside the nanotube, and pulsed measurements together with numerical simulations confirmed the capability to record fast electrophysiological signals. Systematic studies of the probe bandwidth in different ionic concentration solutions revealed the underlying mechanism governing the time response. In addition, the bandwidth effect of phospholipid coatings, which are important for intracellular recording, was investigated and modeled. The robustness of these sub-10-nm bioelectronics probes for intracellular interrogation was verified by optical imaging and recording the transmembrane resting potential of HL-1 cells. These ultrasmall bioelectronic probes enable direct detection of cellular electrical activity with highest spatial resolution achieved to date, and with further integration into larger chip arrays could provide a unique platform for ultra-high-resolution mapping of activity in neural networks and other systems.

  12. The Double Star mission

    Directory of Open Access Journals (Sweden)

    Liu

    2005-11-01

    Full Text Available The Double Star Programme (DSP was first proposed by China in March, 1997 at the Fragrant Hill Workshop on Space Science, Beijing, organized by the Chinese Academy of Science. It is the first mission in collaboration between China and ESA. The mission is made of two spacecraft to investigate the magnetospheric global processes and their response to the interplanetary disturbances in conjunction with the Cluster mission. The first spacecraft, TC-1 (Tan Ce means "Explorer", was launched on 29 December 2003, and the second one, TC-2, on 25 July 2004 on board two Chinese Long March 2C rockets. TC-1 was injected in an equatorial orbit of 570x79000 km altitude with a 28° inclination and TC-2 in a polar orbit of 560x38000 km altitude. The orbits have been designed to complement the Cluster mission by maximizing the time when both Cluster and Double Star are in the same scientific regions. The two missions allow simultaneous observations of the Earth magnetosphere from six points in space. To facilitate the comparison of data, half of the Double Star payload is made of spare or duplicates of the Cluster instruments; the other half is made of Chinese instruments. The science operations are coordinated by the Chinese DSP Scientific Operations Centre (DSOC in Beijing and the European Payload Operations Service (EPOS at RAL, UK. The spacecraft and ground segment operations are performed by the DSP Operations and Management Centre (DOMC and DSOC in China, using three ground station, in Beijing, Shanghai and Villafranca.

  13. Comparison of the Therapeutic Efficacy of Double-Modality Therapy ...

    African Journals Online (AJOL)

    Comparison of the Therapeutic Efficacy of Double-Modality Therapy, Phonophoresis and Cryotherapy in the Management of Musculoskeletal Injuries in Adult ... Ultrasound at an intensity of 1.5 W/cm² and frequency of 1MHz was used to apply methyl salicylate while intermittent cryotherapy was the mode of application.

  14. Ultrasonic investigation of mechanical properties of double base rocket propellants

    NARCIS (Netherlands)

    Schroeff, J.A. van der; Boer, R.S. de

    1976-01-01

    For a series of double base rocket propellants and for poly-methylmethacrylate (PMMA) the longitudinal and transverse sound wave velocities are measured at a frequency of 0.351 MHz in t h e temperature range of −40°C to +60°C. The relations between these acoustic properties and mechanical properties

  15. Double your money

    International Nuclear Information System (INIS)

    Moxon, Suzanne

    1998-01-01

    The government-owned Hydro-Quebec was instructed to take certain actions, one of which was to increase profits. The company has published a report describing its plans for 1998-2002. The company expects to increase sales and double its income over the five years. Hydro-Quebec (which produces or purchases 97% of the electricity consumed in the province) will freeze prices until April 2002. Environmental considerations and liaison with local communities are included in the 5-year plan. The company expects to invest c$1.2B in international markets over the five years and C$20M per year are earmarked for research. (UK)

  16. Multimillijoule, highly coherent x-ray laser at 21 nm operating in deep saturation through double-pass amplification

    Czech Academy of Sciences Publication Activity Database

    Rus, Bedřich; Mocek, Tomáš; Präg R., Ansgar; Kozlová, Michaela; Jamelot, G.; Carillon, A.; Ros, D.; Joyeux, D.; Phalippou, D.

    2002-01-01

    Roč. 66, č. 6 (2002), s. 063806-1 - 063806-11 ISSN 1050-2947 R&D Projects: GA MŠk LN00A100; GA AV ČR IAA1010014 Institutional research plan: CEZ:AV0Z1010921 Keywords : x-ray lasers * laser plasma * x-ray spectroscopy x-ray optics Subject RIV: BH - Optics, Masers, Lasers Impact factor: 2.986, year: 2002

  17. Injection molding of high aspect ratio sub-100 nm nanostructures

    DEFF Research Database (Denmark)

    Matschuk, Maria; Larsen, Niels B

    2013-01-01

    as described by height, width and uniformity of the nanoscopic features. Use of a mold temperature transiently above the polymer glass transition temperature (Tg) was the most important factor in increasing the replication fidelity. Surface coating of the nickel molds with a fluorocarbon-containing thin film...... with FDTS. Reduced adhesion forces are consistent with lowered friction that reduces the risk of fracturing the nanoscopic pillars during demolding. Optimized mold surface chemistry and associated injection molding conditions permitted the fabrication of square arrays of 40 nm wide and 107 nm high (aspect...

  18. Absolute-frequency measurements with a stabilized near-infrared optical frequency comb from a Cr:forsterite laser

    Science.gov (United States)

    Corwin, K. L.; Thomann, I.; Dennis, T.; Fox, R. W.; Swann, W.; Curtis, E. A.; Oates, C. W.; Wilpers, G.; Bartels, A.; Gilbert, S. L.; Hollberg, L.; Newbury, N. R.; Diddams, S. A.; Nicholson, J. W.; Yan, M. F.

    2004-02-01

    A frequency comb is generated with a chromium-doped forsterite femtosecond laser, spectrally broadened in a dispersion-shifted highly nonlinear fiber, and stabilized. The resultant evenly spaced comb of frequencies ranges from 1.1 to beyond 1.8 μm. The frequency comb was referenced simultaneously to the National Institute of Standards and Technology's optical frequency standard based on neutral calcium and to a hydrogen maser that is calibrated by a cesium atomic fountain clock. With this comb we measured two frequency references in the telecommunications band: one half of the frequency of the d/f crossover transition in 87Rb at 780 nm, and the methane ν2 + 2ν3 R(8) line at 1315 nm.

  19. Extending Double Optical Gating to the Midinfrared

    Science.gov (United States)

    Gorman, Timothy; Camper, Antoine; Agostini, Pierre; Dimauro, Louis

    2015-05-01

    In the past decade there has been great interest in creating broadband isolated attosecond pulses (IAPs). Primarily these IAPs have been generated using Ti:Sapphire 800nm short pulses, namely through spatiotemporal gating with the attosecond lighthouse technique, amplitude gating, polarization gating, and double optical gating (DOG). Here we present theoretical calculations and experimental investigations into extending DOG to using a 2 μm driving wavelength, the benefits of which include extended harmonic cutoff and longer input driving pulse durations. It is proposed that broadband IAPs with cutoffs extending up to 250 eV can be generated in Argon by using >30 fs pulses from the passively-CEP stabilized 2 μm idler out of an optical parametric amplifier combined with a collinear DOG experimental setup.

  20. Single-mask double-patterning lithography

    Science.gov (United States)

    Ghaida, Rani S.; Torres, George; Gupta, Puneet

    2009-10-01

    This paper proposes shift-trim double patterning lithography (ST-DPL), a cost-effective method for achieving 2× pitchrelaxation with a single photomask (especially at polysilicon layer). The mask is re-used for the second exposure by applying a translational mask-shift. Extra printed features are then removed using a non-critical trim exposure. The viability of ST-DPL is demonstrated. The proposed method has many advantages with virtually no area overhead (DPL, (2) reduces overlay errors between the two patterns and can virtually eliminate it in some process implementations, (3) alleviates the bimodal problem in doublepatterning, and (4) enhances throughput of first-rate scanners. We implement a small 45nm standard-cell library and small benchmark designs with ST-DPL to illustrate its viability.

  1. Continuous-wave optical parametric oscillator pumped by a fiber laser green source at 532 nm.

    Science.gov (United States)

    Samanta, G K; Kumar, S Chaitanya; Das, Ritwick; Ebrahim-Zadeh, M

    2009-08-01

    We report a high-power, cw, singly resonant optical parametric oscillator (SRO) using a simple, compact fiber pump laser architecture in the green. The SRO, based on MgO:sPPLT, is pumped by 9.6 W of single-frequency cw radiation at 532 nm obtained by single-pass second-harmonic generation (SHG) of a 30 W Yb fiber laser, also in MgO:sPPLT. Using two identical crystals of 30 mm length for SHG and SRO, we generate cw idler powers of up to 2 W over 855-1408 nm, with a peak-to-peak power stability <11.7% over 40 min, in a TEM(00) spatial mode with M(2)<1.26. Using finite output coupling of the resonant wave, we extract 800 mW of signal power with peak-to-peak power stability <10.7% over 40 min, and a frequency stability <75 MHz over 15 min. The signal and idler output have TEM(00) beam profile with M(2)<1.52 across the tuning range.

  2. Cavity Control and Panel Control Strategies in Double-Panel Structures for Transmitted Noise Reduction

    NARCIS (Netherlands)

    Ho, J.; Kalverboer, J.; Berkhoff, Arthur P.

    2012-01-01

    Investigation and comparisons of the cavity control and the panel control in a double-panel structure are presented in this paper. The double-panel structure, which comprises two panels with air in the gap, provides the advantages of low sound-transmission at high frequency, low heat-transmission

  3. Color dissociation artifacts in double Maddox rod cyclodeviation testing.

    Science.gov (United States)

    Simons, K; Arnoldi, K; Brown, M H

    1994-12-01

    The double Maddox rod test, based on a red Maddox rod in front of one eye and a clear Maddox rod in front of the other, is used to measure cyclodeviation, typically in patients with superior oblique muscle pareses. Discrepant results between the double Maddox rod test and other torsion measures, and reports of "paradoxic" cyclodeviation in the normal eye of some patients with superior oblique paresis, suggest the two-color format of the double Maddox rod test may produce artifactual torsion measures. Forty patients with superior oblique paresis were tested twice using the double Maddox rod test, reversing the red and white Maddox rods between eyes for the second test, and 18 were tested further with same-color red or clear Maddox rods in front of both eyes. With the standard double Maddox rod test, 33 (83%) of 40 patients localized their cyclodeviation to the eye viewing through the red Maddox rod, irrespective of laterality of the paresis or fixation preference. In all 33 patients, laterality of the perceived torsion changed between eyes when testing was repeated with red and white Maddox rods interchanged between eyes. With same-color Maddox rods before both eyes, 17 (94%) of 18 patients localized extorsion to the paretic eye. There was 7.6:1 ratio of luminance transmission and a 1.6:1 ratio of grating spatial frequency bandpass in the plano meridian between the clear and red Maddox rods, which appear to be responsible for the double Maddox rod test artifact. The traditional double Maddox rod test may produce artifactual cyclodeviation measurements. An alternative version of the test, based on same-color Maddox rods in front of both eyes, is proposed. The relatively high spatial frequency bandpass characteristics of the plano meridian of the Maddox rod (as high as 20/25 Snellen equivalent resolution through the clear Maddox rod) also suggests double Maddox rod testing should be conducted in a dark room to avoid biases from visual environment cues.

  4. Radiation-shielded double crystal X-ray monochromator for JET

    International Nuclear Information System (INIS)

    Barnsley, R.; Morsi, H.W.; Rupprecht, G.; Kaellne, E.

    1989-01-01

    A double crystal X-ray monochromator for absolute wavelength and intensity measurements with very effective shielding of its detector against neutrons and hard X-rays was brought into operation at JET. Fast wavelength scans were taken of impurity line radiation in the wavelength region from about 0.1 nm to 2.3 nm, and monochromatic as well as spectral line scans, for different operational modes of JET. (author) 5 refs., 4 figs

  5. Possibility of 1-nm level localization of a single molecule with gap-mode surface-enhanced Raman scattering

    International Nuclear Information System (INIS)

    Choi, Han Kyu; Kim, Zee Hwan

    2015-01-01

    The electromagnetic (EM) enhancement mechanism of surface-enhanced Raman scattering (SERS) has been well established through 30 years of extensive investigation: molecules adsorbed on resonantly driven silver or gold nanoparticles (NPs) experience strongly enhanced field and thus show enhanced Raman scattering. Even stronger SERS enhancement is possible with a gap structure in which two or more NPs form assemblies with gap sizes of 1 nm or less. We have theoretically shown that the measurement of SERS angular distribution can reveal the position of a single molecule near the gap with 1-nm accuracy, even though the spatial extent of the enhanced field is ~10 nm. Real implementation of such experiment requires extremely well-defined (preferably a single crystal) dimeric junctions. Nevertheless, the experiment will provide spatial as well as frequency domain information on single-molecule dynamics at metallic surfaces

  6. Conjugated 12 nm long oligomers as molecular wires in nanoelectronics

    DEFF Research Database (Denmark)

    Søndergaard, Roar; Strobel, Sebastian; Bundgaard, Eva

    2009-01-01

    products. Final end group functionalities of the OPVs were introduced either as the first step (alcohol) or the last step (thioacetate). We further demonstrate a fabrication method for well defined nanogap electrode devices based on silicon-on-insulator technology, featuring a gap distance of down to 9 nm...

  7. 850-nm oxide VCSEL development at Hewlett-Packard

    Science.gov (United States)

    Deng, Hongyu; Dudley, James J.; Lim, Sui F.; Lei, Chun; Liang, Bing; Tashima, M.; Hodge, Lee A.; Zhang, Xuemei; Herniman, John; Herrick, Robert W.

    1999-04-01

    Oxide confined VCSELs are being developed at Hewlett-Packard for the next-generation low cost fiber optics communication applications. Compared to the existing 850 nm implant confined VCSELs, the oxide VCSELs have lower operating voltages, higher slope efficiencies, and better modal bandwidth characteristics. Preliminary data on epitaxy and oxidation control uniformity, device performance, and reliability will be discussed.

  8. 650 nm Laser stimulated dating from Side Antique Theatre, Turkey

    International Nuclear Information System (INIS)

    Doğan, M.; Meriç, N.

    2014-01-01

    Samples were taken from the archeological excavation site, which was at the backs of the Side Antique Theatre. Samples were taken from under the base rock in this area. Polymineral fine grains were examined to determine the ages of the sediments. Samples gathered from the Side Antique Theatre were investigated through using the SAR method. Firstly, one part of the samples were evaluated by using conventional IRSL reading head model of (ELSEC-9010) which is infrared (880±80 nm) stimulation source with Schott BG39 filter. The IRSL age dating with feldspar minerals, gives a number of overestimated or underestimated age values as a result. A new reading head was proposed with the following configuration attachments for overestimation of equivalent dose rates. Measurements were done with this newly designed red laser stimulating reading head which works with Elsec 9010 OSL age dating system. SAR measurements were performed by (650±10 nm) red laser light source with two Schott BG3 filters. With usage of the new designed reading head; closer results were obtained in comparision with the Antique Theatre′s expected age range. Fading rates were taken into consideration and these corrections were also handled for true age results. - Highlights: • Polymineral fine grain feldspar minerals were used for dating. • Two different reading heads were used to determine equivalent doses. • IR stimulated (880 nm) and laser stimulated (650 nm) dating results were compared

  9. EST Table: NM_001130892 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available NM_001130892 Tk 10/09/29 94 %/250 aa ref|NP_001124364.1| tachykinin [Bombyx mori] dbj|BAG50368.1| tachykinin...1 aa gi|189240200|ref|XP_975364.2| PREDICTED: similar to preprotachykinin [Tribolium castaneum] FS804780 ...

  10. Isolation and genomic characterization of Escherichia coli O157:NM ...

    African Journals Online (AJOL)

    Human diseases caused by Escherichia coli O157:NM and E. coli O157:H7 strains have been reported throughout the world. In developed countries, serotype O157:H7 represents the major cause of human diseases; however, there have been increasing reports of non-O157 Shiga toxin (Stx)-producing E. coli strains ...

  11. Direct visualization of fluid dynamics in sub-10 nm nanochannels.

    Science.gov (United States)

    Li, Huawei; Zhong, Junjie; Pang, Yuanjie; Zandavi, Seyed Hadi; Persad, Aaron Harrinarine; Xu, Yi; Mostowfi, Farshid; Sinton, David

    2017-07-13

    Optical microscopy is the most direct method to probe fluid dynamics at small scales. However, contrast between fluid phases vanishes at ∼10 nm lengthscales, limiting direct optical interrogation to larger systems. Here, we present a method for direct, high-contrast and label-free visualization of fluid dynamics in sub-10 nm channels, and apply this method to study capillary filling dynamics at this scale. The direct visualization of confined fluid dynamics in 8-nm high channels is achieved with a conventional bright-field optical microscope by inserting a layer of a high-refractive-index material, silicon nitride (Si 3 N 4 ), between the substrate and the nanochannel, and the height of which is accurately controlled down to a few nanometers by a SiO 2 spacer layer. The Si 3 N 4 layer exhibits a strong Fabry-Perot resonance in reflection, providing a sharp contrast between ultrathin liquid and gas phases. In addition, the Si 3 N 4 layer enables robust anodic bonding without nanochannel collapse. With this method, we demonstrate the validity of the classical Lucas-Washburn equation for capillary filling in the sub-10 nm regime, in contrast to the previous studies, for both polar and nonpolar liquids, and for aqueous salt solutions.

  12. Blue light (470 nm) effectively inhibits bacterial and fungal growth

    Science.gov (United States)

    The activity of blue light (470nm) alone on (1) bacterial viability, and (2) with a food grade photosensitizer on filamentous fungal viability, was studied. Suspensions of the bacteria Leuconostoc mesenteroides (LM), Bacillus atrophaeus (BA), and Pseudomonas aeruginosa (PA) were prepared and aliquo...

  13. EST Table: NM_001123349 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available NM_001123349 18w 10/09/29 92 %/1295 aa ref|NP_001116821.1| 18 wheeler [Bombyx mori] dbj|BAB85498.1| 18 wheel...|Amel|GB15177-PA 10/09/10 58 %/1242 aa gi|91076478|ref|XP_972409.1| PREDICTED: similar to 18 wheeler [Tribolium castaneum] FS922922 ...

  14. EST Table: NM_001172816 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available NM_001172816 Ser2 10/09/29 87 %/1722 aa ref|NP_001166287.1| sericin 2 isoform 1 pre...cursor [Bombyx mori] gb|ADA84147.1| sericin 2 precursor [Bombyx mori] 10/09/13 low homology 10/08/29 low hom

  15. EST Table: NM_001172817 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available NM_001172817 Ser2 11/12/09 n.h 10/09/29 81 %/864 aa ref|NP_001166288.1| sericin 2 i...soform 2 precursor [Bombyx mori] gb|ADB04958.1| sericin 2 precursor [Bombyx mori] 10/09/13 low homology 10/0

  16. Super-selective cryogenic etching for sub-10 nm features

    Science.gov (United States)

    Liu, Zuwei; Wu, Ying; Harteneck, Bruce; Olynick, Deirdre

    2013-01-01

    Plasma etching is a powerful technique for transferring high-resolution lithographic masks into functional materials. Significant challenges arise with shrinking feature sizes, such as etching with thin masks. Traditionally this has been addressed with hard masks and consequently additional costly steps. Here we present a pathway to high selectivity soft mask pattern transfer using cryogenic plasma etching towards low-cost high throughput sub-10 nm nanofabrication. Cryogenic SF6/O2 gas chemistry is studied for high fidelity, high selectivity inductively coupled plasma etching of silicon. Selectivity was maximized on large features (400 nm-1.5 μm) with a focus on minimizing photoresist etch rates. An overall anisotropic profile with selectivity around 140:1 with a photoresist mask for feature size 1.5 μm was realized with this clean, low damage process. At the deep nanoscale, selectivity is reduced by an order of magnitude. Despite these limits, high selectivity is achieved for anisotropic high aspect ratio 10 nm scale etching with thin polymeric masks. Gentler ion bombardment resulted in planar-dependent etching and produced faceted sub-100 nm features.

  17. Comparing the 810nm Diode Laser with Conventional Surgery in ...

    African Journals Online (AJOL)

    Aim: To compare the use of the 810nm diode laser with conventional surgery in the management of soft tissue mucogingival problems associated with orthodontic treatment. Methods: Orthodontic patients requiring different soft tissue surgical procedures were randomly assigned to receive conventional surgery or soft tissue ...

  18. 30 Gbps bottom-emitting 1060 nm VCSEL

    DEFF Research Database (Denmark)

    Tatarczak, Anna; Zheng, Y.; Rodes, G. A.

    2014-01-01

    1060 nm VCSEL-based data transmission over 50 m OM3 MMF at 30 Gbit/s is experimentally demonstrated. A highly-strained bottom-emitting QW VCSEL with p-type modulation doping is used with 3.77 mA bias and 0.55 V data amplitude....

  19. EST Table: NM_001046937 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available NM_001046937 LOC732938 10/09/29 100 %/220 aa ref|NP_001040402.1| preimplantation pr...otein [Bombyx mori] gb|ABF51322.1| preimplantation protein [Bombyx mori] 10/09/13 79 %/222 aa FBpp0234606|Dv

  20. EST Table: NM_001044003 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available NM_001044003 Leb1/2 11/12/09 n.h 10/09/29 75 %/179 aa ref|NP_001037468.1| lebocin-1.../2 precursor [Bombyx mori] sp|P54684.1|LEB1_BOMMO RecName: Full=Lebocin-1/2; Flags: Precursor gb|AAB35218.1| leboc

  1. 65 nm CMOS Monolithically Integrated sub-THz transmitter

    NARCIS (Netherlands)

    Hu, X.; Tripodi, L.; Matters-Kammerer, M.K.; Cheng, S.; Rydberg, A.

    2011-01-01

    This letter presents a transmitter for sub-THz radiation (up to 160GHz), which consists of a nonlinear transmission line (NLTL) and anextremely wideband (EWB) slot antenna on a silicon substrate of lowresistivity (10 Ohms•cm). The fabrication was realized using a commercially available 65 nm CMOS

  2. FREQUENCY DETERMINATION OF HIGH-FREQUENCY LINK FOR PERCPECTIVE ELECTRIC ROLLING STOCK

    Directory of Open Access Journals (Sweden)

    D. O. Zabarylo

    2014-12-01

    Full Text Available Purpose. Total mileage of Ukrainian electric railways is distributed approximately equally between the areas of direct and alternating current. A double system of electric rolling stock is used to pass jointing places of different current kinds without train’s stop. Therefore introduction of such rolling stock of a new concept that is using an asynchronous traction drive is prospective for Ukrainian railways. Apart from advantages a rolling stock of similar concept has significant disadvantages, it is pulse energy consumption from the power supply, and it can affect the reliability of track automatic devices, and consequently, the train traffic safety. In addition the specific power of traction transformer is considerably inferior to the power density of other traction elements. The promising schemes using an intermediary link of increased frequency, which consist of a transformer and inverter, have been proposed for disadvantages amendments. The main task for the further introduction of prospective circuit is to determine the operating frequency for high frequency link. Methodology. The method of thermal parameters calculation of semiconductor devices has been used for determination switching transistors of maximum operating frequency. To obtain analytical expressions curves of energy, released during the IGBT (insulated-gate bipolar transistor switching from its current load approximation method is used. Findings. The permissible frequency of low-frequency link is determinated by load current of intermediate transformer. Operating frequency range of a link depending on load current has been determined. A comparative analysis of the switching characteristics of 65 class IGBT production by companies Infineon and ABB has been performed. Originality. The further determination method of the maximum operating frequency of intermediate link for circuit with high-frequency transformer has been developed. Practical value. The established operating

  3. Tracking frequency laser distance gauge

    International Nuclear Information System (INIS)

    Phillips, J.D.; Reasenberg, R.D.

    2005-01-01

    Advanced astronomical missions with greatly enhanced resolution and physics missions of unprecedented accuracy will require laser distance gauges of substantially improved performance. We describe a laser gauge, based on Pound-Drever-Hall locking, in which the optical frequency is adjusted to maintain an interferometer's null condition. This technique has been demonstrated with pm performance. Automatic fringe hopping allows it to track arbitrary distance changes. The instrument is intrinsically free of the nm-scale cyclic bias present in traditional (heterodyne) high-precision laser gauges. The output is a radio frequency, readily measured to sufficient accuracy. The laser gauge has operated in a resonant cavity, which improves precision, can suppress the effects of misalignments, and makes possible precise automatic alignment. The measurement of absolute distance requires little or no additional hardware, and has also been demonstrated. The proof-of-concept version, based on a stabilized HeNe laser and operating on a 0.5 m path, has achieved 10 pm precision with 0.1 s integration time, and 0.1 mm absolute distance accuracy. This version has also followed substantial distance changes as fast as 16 mm/s. We show that, if the precision in optical frequency is a fixed fraction of the linewidth, both incremental and absolute distance precision are independent of the distance measured. We discuss systematic error sources, and present plans for a new version of the gauge based on semiconductor lasers and fiber-coupled components

  4. Frequency Measurement of Tellurium Lines Near Calcium

    Science.gov (United States)

    Dammalapati, Umakanth; Harada, Ken-ichi; Inoue, Takeshi; Ito, Saki; Kawamura, Hirokazu; Sakamoto, Kosuke; Tanaka, Kazuo; Uchiyama, Aiko; Yoshioka, Risa; Sakemi, Yasuhiro

    2017-12-01

    We report measurement of frequencies of tellurium lines with respect to atomic calcium employing a 423 nm commercial violet laser diode placed in an extended cavity. Doppler-free saturated absorption spectroscopy of molecular tellurium is performed on three lines, which are lower and higher in energy to the calcium 4s2 1S0-4s4p 1P1 transition. The measured frequency difference of 717(13) MHz between the strong absorption line, #1508 in the tellurium atlas and the calcium transition is in agreement within 10% of the values available from literature. Wavenumbers of two new tellurium lines are derived from the measurement. In addition, spectroscopy and laser cooling and trapping of francium (n = 7) on the ns 2S1/2-(n + 1)p 2P3/2 transition and spectroscopy of Te2 lines near francium could be performed employing the 423 nm diode laser.

  5. Room temperature single longitudinal mode laser output at 1645 nm from a laser-diode pumped Er:YAG nonplanar ring oscillator.

    Science.gov (United States)

    Yao, B Q; Yu, X; Liu, X L; Duan, X M; Ju, Y L; Wang, Y Z

    2013-04-08

    We report on a monolithic 1645 nm Er:YAG nonplanar ring oscillator (NPRO) resonantly pumped by a fiber-coupled laser diode. In the experiment, an up to 550 mW single frequency laser output at 1645.2 nm was obtained, corresponding to a slope efficiency of 19.1% and an absolute efficiency of 6.0%. The beam quality M2 was measured to be 2.1 at the highest output power.

  6. Multiple Frequency Parametric Sonar

    Science.gov (United States)

    2015-09-28

    300003 1 MULTIPLE FREQUENCY PARAMETRIC SONAR STATEMENT OF GOVERNMENT INTEREST [0001] The invention described herein may be manufactured and...a method for increasing the bandwidth of a parametric sonar system by using multiple primary frequencies rather than only two primary frequencies...2) Description of Prior Art [0004] Parametric sonar generates narrow beams at low frequencies by projecting sound at two distinct primary

  7. Study of a new frequency conversion configuration techniques applied to broadband pulse for high-power lasers

    International Nuclear Information System (INIS)

    Raoult, Fabrice

    1999-01-01

    The generation of broadband pulses is of prime importance to produce ultra short pulses or to use in optical smoothing techniques. We report in this Ph.D. work an experimental verification of a previously published concept which, by adapting a chirped pulse amplification (CPA) configuration, allows efficient frequency conversion of broadband energetic pulse. This method is general in that it allows many kinds of controls such as producing a broadband or a narrow spectral bandwidth pulse starting from a broadband ultra short pulse while keeping a high efficiency. In a first set of experiments we have produced with a high efficiency a broadband ultra short UV pulse by frequency tripling an ultra short pulse in the near infra red. The experiments were performed using a Ti:sapphire femtosecond laser and a CPA amplifier configuration. The tripling scheme relied on a KDP Type I-Type II collinear configuration. We obtain a third harmonic 1.2 nm spectral bandwidth, only limited by the initial pulse spectrum with an overall efficiency of 40%. A major step in the experiments has consisted in compressing the UV pulse. To measure the pulse profile we have implemented a simple method so called namely the reconstruction of the phase through self-phase modulation, we have obtained a 220 fs duration. Then, we studied theoretical limitations and performances of the frequency conversion process with adapted chirp. We have shown that the main issue was the non linear chirp law due to the dispersing line device. In a second set of experiments we have produced a narrow bandwidth pulse by frequency doubling an ultra short pulse in the near infra red with same high efficiency. A KDP Type I non collinear configuration was used and a spectral bandwidth less than 0.1 nm was obtained. The efficiency achieved was comparable with frequency doubling of monochromatic pulse. In a last set of experiments we have applied the technique of adapting the chirp in order to obtain a fitted temporal pulse

  8. Multi-frequency excitation

    KAUST Repository

    Younis, Mohammad I.

    2016-03-10

    Embodiments of multi-frequency excitation are described. In various embodiments, a natural frequency of a device may be determined. In turn, a first voltage amplitude and first fixed frequency of a first source of excitation can be selected for the device based on the natural frequency. Additionally, a second voltage amplitude of a second source of excitation can be selected for the device, and the first and second sources of excitation can be applied to the device. After applying the first and second sources of excitation, a frequency of the second source of excitation can be swept. Using the methods of multi- frequency excitation described herein, new operating frequencies, operating frequency ranges, resonance frequencies, resonance frequency ranges, and/or resonance responses can be achieved for devices and systems.

  9. Frequency selectivity at very low centre frequencies

    DEFF Research Database (Denmark)

    Orellana, Carlos Andrés Jurado; Pedersen, Christian Sejer; Marquardt, Torsten

    2010-01-01

    measurements based on OAE suppression techniques and notched-noise masking data psychophysically measured for centre frequencies in the range 50-125 Hz, this study examines how individual differences in frequency selectivity, as well as in masking, may occur at very low CFs due to individual differences...

  10. Over 8 W high peak power UV laser with a high power Q-switched Nd:YVO4 oscillator and the compact extra-cavity sum-frequency mixing

    International Nuclear Information System (INIS)

    Yan, X P; Liu, Q; Gong, M; Wang, D S; Fu, X

    2009-01-01

    A 8.2 W UV laser was reported with the compact extra-cavity sum-frequency mixing. The IR fundamental frequency source was a high power and high beam quality Q-switched Nd:YVO 4 oscillator. 38 W fundamental frequency laser at 1064 nm was obtained at the pulse repetition rate of 450 kHz with the beam quality factors of M 2 x = 1.27, M 2 y = 1.21. The type I and type II phase-matched LBO crystals were used as the extra-cavity frequency doubling and mixing crystals respectively. At 38 kHz, 8.2 W UV laser at 355 nm was achieved with the pulse duration of 8 ns corresponding to the pulse peak power as high as 27 kW, and the optical-optical conversion efficiency from IR to UV was 25.6%. The output characteristics of the IR and the harmonic generations varying with the pulse repetition rate were also investigated detailedly

  11. Characteristics of the Single-Longitudinal-Mode Planar-Waveguide External Cavity Diode Laser at 1064 nm

    Science.gov (United States)

    Numata, Kenji; Alalusi, Mazin; Stolpner, Lew; Margaritis, Georgios; Camp, Jordan; Krainak, Michael

    2014-01-01

    We describe the characteristics of the planar-waveguide external cavity diode laser (PW-ECL). To the best of our knowledge, it is the first butterfly-packaged 1064 nm semiconductor laser that is stable enough to be locked to an external frequency reference. We evaluated its performance from the viewpoint of precision experiments. Using a hyperfine absorption line of iodine, we suppressed its frequency noise by a factor of up to 104 at 10 mHz. The PWECL's compactness and low cost make it a candidate to replace traditional Nd:YAG nonplanar ring oscillators and fiber lasers in applications that require a single longitudinal mode.

  12. Comprehensive analysis of sub-20 nm black phosphorus based junctionless-recessed channel MOSFET for analog/RF applications

    Science.gov (United States)

    Kumar, Ajay; Tripathi, M. M.; Chaujar, Rishu

    2018-04-01

    In this work, a comprehensive analog and RF performance of a novel Black Phosphorus-Junctionless-Recessed Channel (BP-JL-RC) MOSFET has been explored at 45 nm technology node (Gate length = 20 nm). The integration of black phosphorus with junctionless recessed channel MOSFET, leads to higher drain current of about 0.3 mA and excellent switching ratio (of the order of 1011) due to reduced off-current which leads to improvement in sub-threshold slope (SS) (67mV/dec). Further, RF performance metrics have also been studied with an aim to analyze high-frequency performance. The following FOMs have been evaluated: cut-off frequency (fT), maximum oscillator frequency (fMAX), stern stability factor, various power gains and parasitic capacitances at THz frequency range. Thus, in addition to the high packing density offered by RC MOSFET, the proposed design finds numerous application at THz frequency making it a promising candidate at wafer scale integration level.

  13. Double profunda brachii artery

    Directory of Open Access Journals (Sweden)

    Gavishiddappa A Hadimani

    2016-01-01

    Full Text Available Brachial artery (BA is a continuation of the axillary artery at the lower border of teres major. In the cubital fossa, BA divides into radial artery and ulnar artery as terminal branches. Large branch given from the BA in the upper part is profunda brachii artery. In the present case, we noticed double profunda brachii that arises from the BA. They are profunda brachii artery 1 and profunda brachii artery 2. Profunda brachii artery 1 arises in the proximal part of the BA and profunda brachii artery 2 arises distal to the profunda brachii artery 1. Both the arteries run inferolaterally in the spiral groove along with radial nerve. Variations of profunda brachii artery are important during harvesting of the lateral arm flaps and may lead to inadvertent injury during percutaneous arterial catheterization or injection of drugs.

  14. Double-Skin Facade

    DEFF Research Database (Denmark)

    Kalyanova, Olena

    , transparent insulation and preheating operation modes of DSF cavity. The data sets include measurements of naturally induced air flow, temperature gradients, velocity profiles, climate data, etc. Two data sets were used for further empirical validation of building simulation software for DSF modelling within...... favored by companies and their employees. To bring the reduction of energy use in these buildings application of suitable tools and methods is necessary to achieve successful design solutions. Earlier work on the topic of DSF modelling was examined from various publications. As a result, the main...... to perform the simulations. To fill in the gap of lacking experimental data a range of measurements was carried out in an outdoor, double-skin façade full-scale test facility ‘The Cube'. As a result, three complete sets of experimental data were composed. These are available for external air curtain...

  15. GENERALIZED DOUBLE PARETO SHRINKAGE.

    Science.gov (United States)

    Armagan, Artin; Dunson, David B; Lee, Jaeyong

    2013-01-01

    We propose a generalized double Pareto prior for Bayesian shrinkage estimation and inferences in linear models. The prior can be obtained via a scale mixture of Laplace or normal distributions, forming a bridge between the Laplace and Normal-Jeffreys' priors. While it has a spike at zero like the Laplace density, it also has a Student's t -like tail behavior. Bayesian computation is straightforward via a simple Gibbs sampling algorithm. We investigate the properties of the maximum a posteriori estimator, as sparse estimation plays an important role in many problems, reveal connections with some well-established regularization procedures, and show some asymptotic results. The performance of the prior is tested through simulations and an application.

  16. Thermal coagulation-induced changes of the optical properties of normal and adenomatous human colon tissues in vitro in the spectral range 400 1100 nm

    Science.gov (United States)

    Ao, Huilan; Xing, Da; Wei, Huajiang; Gu, Huaimin; Wu, Guoyong; Lu, Jianjun

    2008-04-01

    The absorption coefficients, the reduced scattering coefficients and the optical penetration depths for native and coagulated human normal and adenomatous colon tissues in vitro were determined over the range of 400-1100 nm using a spectrophotometer with an internal integrating sphere system, and the inverse adding-doubling method was applied to calculate the tissue optical properties from diffuse reflectance and total transmittance measurements. The experimental results showed that in the range of 400-1100 nm there were larger absorption coefficients (P thermotherapy (LITT) and photodynamic therapy (PDT). It is necessary to adjust the application parameters of lasers to achieve optimal therapy.

  17. Cryogenic Lifetime Studies of 130 nm and 65 nm CMOS Technologies for High-Energy Physics Experiments

    Energy Technology Data Exchange (ETDEWEB)

    Hoff, James R. [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Deptuch, G. W. [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Wu, Guoying [Southern Methodist Univ., Dallas, TX (United States); Gui, Ping [Southern Methodist Univ., Dallas, TX (United States)

    2015-06-04

    The Long Baseline Neutrino Facility intends to use unprecedented volumes of liquid argon to fill a time projection chamber in an underground facility. Research is under way to place the electronics inside the cryostat. For reasons of efficiency and economics, the lifetimes of these circuits must be well in excess of 20 years. The principle mechanism for lifetime degradation of MOSFET devices and circuits operating at cryogenic temperatures is hot carrier degradation. Choosing a process technology that is, as much as possible, immune to such degradation and developing design techniques to avoid exposure to such damage are the goals. This, then, requires careful investigation and a basic understanding of the mechanisms that underlie hot carrier degradation and the secondary effects they cause in circuits. In this work, commercially available 130 nm and 65 nm nMOS transistors operating at cryogenic temperatures are investigated. Our results show that both technologies achieve the lifetimes required by the experiment. Minimal design changes are necessary in the case of the 130 nm process and no changes whatsoever are necessary for the 65 nm process.

  18. Study of drain-extended NMOS under electrostatic discharge stress in 28 nm and 40 nm CMOS process

    Science.gov (United States)

    Wang, Weihuai; Jin, Hao; Dong, Shurong; Zhong, Lei; Han, Yan

    2016-02-01

    Researches on the electrostatic discharge (ESD) performance of drain-extended NMOS (DeNMOS) under the state-of-the-art 28 nm and 40 nm bulk CMOS process are performed in this paper. Three distinguishing phases of avalanche breakdown stage, depletion region push-out stage and parasitic NPN turn on stage of the gate-grounded DeNMOS (GG-DeNMOS) fabricated under 28 nm CMOS process measured with transmission line pulsing (TLP) test are analyzed through TCAD simulations and tape-out silicon verification detailedly. Damage mechanisms and failure spots of GG-DeNMOS under both CMOS processes are thermal breakdown of drain junction. Improvements based on the basic structure adjustments can increase the GG-DeNMOS robustness from original 2.87 mA/μm to the highest 5.41 mA/μm. Under 40 nm process, parameter adjustments based on the basic structure have no significant benefits on the robustness improvements. By inserting P+ segments in the N+ implantation of drain or an entire P+ strip between the N+ implantation of drain and polysilicon gate to form the typical DeMOS-SCR (silicon-controlled rectifier) structure, the ESD robustness can be enhanced from 1.83 mA/μm to 8.79 mA/μm and 29.78 mA/μm, respectively.

  19. Doubled Color Codes

    Science.gov (United States)

    Bravyi, Sergey

    Combining protection from noise and computational universality is one of the biggest challenges in the fault-tolerant quantum computing. Topological stabilizer codes such as the 2D surface code can tolerate a high level of noise but implementing logical gates, especially non-Clifford ones, requires a prohibitively large overhead due to the need of state distillation. In this talk I will describe a new family of 2D quantum error correcting codes that enable a transversal implementation of all logical gates required for the universal quantum computing. Transversal logical gates (TLG) are encoded operations that can be realized by applying some single-qubit rotation to each physical qubit. TLG are highly desirable since they introduce no overhead and do not spread errors. It has been known before that a quantum code can have only a finite number of TLGs which rules out computational universality. Our scheme circumvents this no-go result by combining TLGs of two different quantum codes using the gauge-fixing method pioneered by Paetznick and Reichardt. The first code, closely related to the 2D color code, enables a transversal implementation of all single-qubit Clifford gates such as the Hadamard gate and the π / 2 phase shift. The second code that we call a doubled color code provides a transversal T-gate, where T is the π / 4 phase shift. The Clifford+T gate set is known to be computationally universal. The two codes can be laid out on the honeycomb lattice with two qubits per site such that the code conversion requires parity measurements for six-qubit Pauli operators supported on faces of the lattice. I will also describe numerical simulations of logical Clifford+T circuits encoded by the distance-3 doubled color code. Based on a joint work with Andrew Cross.

  20. CALIPSO lidar calibration at 532 nm: version 4 nighttime algorithm

    Science.gov (United States)

    Kar, Jayanta; Vaughan, Mark A.; Lee, Kam-Pui; Tackett, Jason L.; Avery, Melody A.; Garnier, Anne; Getzewich, Brian J.; Hunt, William H.; Josset, Damien; Liu, Zhaoyan; Lucker, Patricia L.; Magill, Brian; Omar, Ali H.; Pelon, Jacques; Rogers, Raymond R.; Toth, Travis D.; Trepte, Charles R.; Vernier, Jean-Paul; Winker, David M.; Young, Stuart A.

    2018-03-01

    Data products from the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) on board Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) were recently updated following the implementation of new (version 4) calibration algorithms for all of the Level 1 attenuated backscatter measurements. In this work we present the motivation for and the implementation of the version 4 nighttime 532 nm parallel channel calibration. The nighttime 532 nm calibration is the most fundamental calibration of CALIOP data, since all of CALIOP's other radiometric calibration procedures - i.e., the 532 nm daytime calibration and the 1064 nm calibrations during both nighttime and daytime - depend either directly or indirectly on the 532 nm nighttime calibration. The accuracy of the 532 nm nighttime calibration has been significantly improved by raising the molecular normalization altitude from 30-34 km to the upper possible signal acquisition range of 36-39 km to substantially reduce stratospheric aerosol contamination. Due to the greatly reduced molecular number density and consequently reduced signal-to-noise ratio (SNR) at these higher altitudes, the signal is now averaged over a larger number of samples using data from multiple adjacent granules. Additionally, an enhanced strategy for filtering the radiation-induced noise from high-energy particles was adopted. Further, the meteorological model used in the earlier versions has been replaced by the improved Modern-Era Retrospective analysis for Research and Applications, Version 2 (MERRA-2), model. An aerosol scattering ratio of 1.01 ± 0.01 is now explicitly used for the calibration altitude. These modifications lead to globally revised calibration coefficients which are, on average, 2-3 % lower than in previous data releases. Further, the new calibration procedure is shown to eliminate biases at high altitudes that were present in earlier versions and consequently leads to an improved representation of

  1. Formation of Double Neutron Stars, Millisecond Pulsars and Double ...

    Indian Academy of Sciences (India)

    Edward P. J. Heuvel

    2017-09-12

    Sep 12, 2017 ... Abstract. The 1982 model for the formation of Hulse–Taylor binary radio pulsar PSR B1913+16 is described, which since has become the 'standard model' for the formation of the double neutron stars, confirmed by the. 2003 discovery of the double pulsar system PSR J0737-3039AB. A brief overview is ...

  2. Draping Double-Layer Woven Fabrics Onto Double-Curvature ...

    African Journals Online (AJOL)

    Draping woven fabrics to complex parts with double curvature leads to complex redistribution and reorientation of the yarns in composites reinforced with woven preforms. To reduce the risk of fabric tearing or wrinkling we propose to use double-layer woven fabrics. This paper presents a simulation model for draping

  3. Clock Gating Based Energy Efficient and Thermal Aware Design for Vedic Equation Solver on 28nm and 40nm FPGA

    DEFF Research Database (Denmark)

    Pandey, Bishwajeet; Pandey, Sujeet; Sharma, Shivani

    2016-01-01

    equate that sum to zero and find the value of unknown variable. In order to test the portability of our design, we are operating our design with respective frequency of different mobile architecture. Operating frequency of iPhone 6 is 2100MHz. For thermal analysis of our energy efficient design, we have...

  4. Characterization of Films with Thickness Less than 10 nm by Sensitivity-Enhanced Atomic Force Acoustic Microscopy

    Directory of Open Access Journals (Sweden)

    Muraoka Mikio

    2011-01-01

    Full Text Available Abstract We present a method for characterizing ultrathin films using sensitivity-enhanced atomic force acoustic microscopy, where a concentrated-mass cantilever having a flat tip was used as a sensitive oscillator. Evaluation was aimed at 6-nm-thick and 10-nm-thick diamond-like carbon (DLC films deposited, using different methods, on a hard disk for the effective Young's modulus defined as E/(1 - ν2, where E is the Young's modulus, and ν is the Poisson's ratio. The resonant frequency of the cantilever was affected not only by the film's elasticity but also by the substrate even at an indentation depth of about 0.6 nm. The substrate effect was removed by employing a theoretical formula on the indentation of a layered half-space, together with a hard disk without DLC coating. The moduli of the 6-nm-thick and 10-nm-thick DLC films were 392 and 345 GPa, respectively. The error analysis showed the standard deviation less than 5% in the moduli.

  5. 1060-nm Tunable Monolithic High Index Contrast Subwavelength Grating VCSEL

    DEFF Research Database (Denmark)

    Ansbæk, Thor; Chung, Il-Sug; Semenova, Elizaveta

    2013-01-01

    We present the first tunable vertical-cavity surface-emitting laser (VCSEL) where the top distributed Bragg reflector has been completely substituted by an air-cladded high-index-contrast subwavelength grating (HCG) mirror. In this way, an extended cavity design can be realized by reducing...... the reflection at the semiconductor #x2013;air interface using an anti-reflective coating (ARC). We demonstrate how the ARC can be integrated in a monolithic structure by oxidizing AlGaAs with high Al-content. The HCG VCSEL has the potential to achieve polarization stable single-mode output with high tuning...... efficiency. The HCG VCSEL shows a total tuning range of 16 nm around an emission wavelength of 1060 nm with 1-mW output power....

  6. Optically pumped 1550nm wavelength tunable MEMS VCSEL

    DEFF Research Database (Denmark)

    Sahoo, Hitesh Kumar; Ansbæk, Thor; Ottaviano, Luisa

    2016-01-01

    The paper presents the design and fabrication of an optically pumped 1550nm tunable MEMS VCSEL with anenclosed MEMS. The MEMS is defined in SOI and the active material, an InP wafer with quantum wells arebonded to the SOI and the last mirror is made from the deposition of dielectric materials. Th....... The design bringsin flexibility to fabricate MEMS VCSELs over a wider range of wavelengths. The paper discusses results fromthe simulations and bonding results from fabrication. The device will push the boundaries for wavelength sweepspeed and bandwidth.......The paper presents the design and fabrication of an optically pumped 1550nm tunable MEMS VCSEL with anenclosed MEMS. The MEMS is defined in SOI and the active material, an InP wafer with quantum wells arebonded to the SOI and the last mirror is made from the deposition of dielectric materials...

  7. 76 FR 22015 - Amendment of Class E Airspace; Raton, NM

    Science.gov (United States)

    2011-04-20

    ... Raton, Raton Municipal Airport/Crews Field, NM (Lat. 36 44'30'' N., long. 104 30'08'' W.) Cimarron... of a line 4.4 miles northwest and parallel to the 050 radial of the Cimarron VORTAC, and within 1.6... northeast of the airport, and within 3.7 miles each side of the 050 radial of the Cimarron VORTAC extending...

  8. Space-Qualified 1064 nm Seed and Metrology Laser Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Several instruments that are potential candidates for future space-based NASA missions require a highly stable, single frequency laser oscillator that is wavelength...

  9. Brain lesion induced by 1319nm laser radiation

    Science.gov (United States)

    Yang, Zaifu; Chen, Hongxia; Wang, Jiarui; Chen, Peng; Ma, Ping; Qian, Huanwen

    2010-11-01

    The laser-tissue interaction has not been well defined at the 1319 nm wavelength for brain exposure. The goal of this research effort was to identify the behavioral and histological changes of brain lesion induced by 1319 nm laser. The experiment was performed on China Kunming mice. Unilateral brain lesions were created with a continuous-wave Nd:YAG laser (1319nm). The brain lesions were identified through behavioral observation and histological haematoxylin and eosin (H&E) staining method. The behavior change was observed for a radiant exposure range of 97~773 J/cm2. The histology of the recovery process was identified for radiant exposure of 580 J/cm2. Subjects were sacrificed 1 hour, 1 week, 2 weeks, 3 months, 7 months and 13 months after laser irradiation. Results showed that after laser exposure, behavioral deficits, including kyphosis, tail entasia, or whole body paralysis could be noted right after the animals recovered from anesthesia while gradually disappeared within several days and never recurred again. Histologically, the laser lesion showed a typical architecture dependent on the interval following laser treatment. The central zone of coagulation necrosis is not apparent right after exposure but becomes obvious within several days. The nerotic tissue though may persist for a long time, will finally be completely resorbed. No carbonization granules formed under our exposure condition.

  10. Advanced CMOS device technologies for 45 nm node and below

    Directory of Open Access Journals (Sweden)

    A. Veloso, T. Hoffmann, A. Lauwers, H. Yu, S. Severi, E. Augendre, S. Kubicek, P. Verheyen, N. Collaert, P. Absil, M. Jurczak and S. Biesemans

    2007-01-01

    Full Text Available We review and discuss the latest developments and technology options for 45 nm node and below, with scaled planar bulk MOSFETs and MuGFETs as emerging devices. One of the main metal gate (MG candidates for scaled CMOS technologies are fully silicided (FUSI gates. In this work, by means of a selective and controlled poly etch-back integration process, dual work-function Ni-based FUSI/HfSiON CMOS circuits with record ring oscillator performance (high-VT are reported (17 ps at VDD=1.1 V and 20 pA/μm Ioff, meeting the ITRS 45 nm node requirement for low-power (LP CMOS. Compatibility of FUSI and other MG with known stress boosters like stressed CESL (contact-etch-stop-layer with high intrinsic stress or embedded SiGe in the pMOS S/D regions is validated. To obtain MuGFET devices that are competitive, as compared to conventional planar bulk devices, and that meet the stringent drive and leakage current requirements for the 32 nm node and beyond, higher channel mobilities are required. Results obtained by several strain engineering methods are presented here.

  11. Cultured Human Fibroblast Biostimulation Using a 940 nm Diode Laser

    Directory of Open Access Journals (Sweden)

    Rebeca Illescas-Montes

    2017-07-01

    Full Text Available Background: Fibroblasts are the main cells involved in regeneration during wound healing. The objective was to determine the effect of 940 nm diode laser on cultured human fibroblasts using different irradiation regimens. Methods: The CCD-1064Sk human epithelial fibroblast cell line was treated with a 940 nm diode laser at different energy doses (power: 0.2–1 W and energy density: 1–7 J/cm2 using different transmission modes (continuous or pulsed. The effect on cell growth at 24 and 72 h post-treatment was examined by measuring the proliferative capacity, the impact on the cell cycle, and the effect on cell differentiation. Results: fibroblast proliferative capacity was increased at 24 and 72 h post-treatment as a function of the energy dose. The greatest increase was observed with a power of 0.2 or 0.5 W and energy density between 1 and 4 J/cm2; no difference was observed between continuous and pulsed modes. There were no significant differences in cell cycle between treated groups and controls. α-actin expression was increased by treatment, indicating enhanced cell differentiation. Conclusion: The 940 nm diode laser has biostimulating effects on fibroblasts, stimulating proliferative capacity and cell differentiation without altering the cell cycle. Further researches are necessary to explore its potential clinical usefulness in wound healing.

  12. Cultured Human Fibroblast Biostimulation Using a 940 nm Diode Laser

    Science.gov (United States)

    Illescas-Montes, Rebeca; Melguizo-Rodríguez, Lucía; Manzano-Moreno, Francisco Javier; García-Martínez, Olga; Ruiz, Concepción

    2017-01-01

    Background: Fibroblasts are the main cells involved in regeneration during wound healing. The objective was to determine the effect of 940 nm diode laser on cultured human fibroblasts using different irradiation regimens. Methods: The CCD-1064Sk human epithelial fibroblast cell line was treated with a 940 nm diode laser at different energy doses (power: 0.2–1 W and energy density: 1–7 J/cm2) using different transmission modes (continuous or pulsed). The effect on cell growth at 24 and 72 h post-treatment was examined by measuring the proliferative capacity, the impact on the cell cycle, and the effect on cell differentiation. Results: fibroblast proliferative capacity was increased at 24 and 72 h post-treatment as a function of the energy dose. The greatest increase was observed with a power of 0.2 or 0.5 W and energy density between 1 and 4 J/cm2; no difference was observed between continuous and pulsed modes. There were no significant differences in cell cycle between treated groups and controls. α-actin expression was increased by treatment, indicating enhanced cell differentiation. Conclusion: The 940 nm diode laser has biostimulating effects on fibroblasts, stimulating proliferative capacity and cell differentiation without altering the cell cycle. Further researches are necessary to explore its potential clinical usefulness in wound healing. PMID:28773152

  13. Ion transport in sub-5-nm graphene nanopores

    International Nuclear Information System (INIS)

    Suk, Myung E.; Aluru, N. R.

    2014-01-01

    Graphene nanopore is a promising device for single molecule sensing, including DNA bases, as its single atom thickness provides high spatial resolution. To attain high sensitivity, the size of the molecule should be comparable to the pore diameter. However, when the pore diameter approaches the size of the molecule, ion properties and dynamics may deviate from the bulk values and continuum analysis may not be accurate. In this paper, we investigate the static and dynamic properties of ions with and without an external voltage drop in sub-5-nm graphene nanopores using molecular dynamics simulations. Ion concentration in graphene nanopores sharply drops from the bulk concentration when the pore radius is smaller than 0.9 nm. Ion mobility in the pore is also smaller than bulk ion mobility due to the layered liquid structure in the pore-axial direction. Our results show that a continuum analysis can be appropriate when the pore radius is larger than 0.9 nm if pore conductivity is properly defined. Since many applications of graphene nanopores, such as DNA and protein sensing, involve ion transport, the results presented here will be useful not only in understanding the behavior of ion transport but also in designing bio-molecular sensors

  14. Double parton scattering theory overview

    NARCIS (Netherlands)

    Diehl, Markus; Gaunt, Jonathan R.

    2017-01-01

    The dynamics of double hard scattering in proton-proton collisions is quite involved compared with the familiar case of single hard scattering. In this contribution, we review our theoretical understanding of double hard scattering and of its interplay with other reaction mechanisms.

  15. Sensitive detection and separation of fluorescent derivatives using capillary electrophoresis with laser-induced fluorescence detection with 532nm Nd:YAG laser

    Energy Technology Data Exchange (ETDEWEB)

    Vrabel, Patrik [Department of Analytical Chemistry, Faculty of Science, Masaryk University, Kotlarska 2, 611 37 Brno (Czech Republic); Taborsky, Petr [Department of Analytical Chemistry, Faculty of Science, Masaryk University, Kotlarska 2, 611 37 Brno (Czech Republic); Ryvolova, Marketa [Department of Analytical Chemistry, Faculty of Science, Masaryk University, Kotlarska 2, 611 37 Brno (Czech Republic); Havel, Josef [Department of Analytical Chemistry, Faculty of Science, Masaryk University, Kotlarska 2, 611 37 Brno (Czech Republic); Preisler, Jan [Department of Analytical Chemistry, Faculty of Science, Masaryk University, Kotlarska 2, 611 37 Brno (Czech Republic)]. E-mail: preisler@chemi.muni.cz

    2006-06-15

    Capillary electrophoresis with laser-induced fluorescence detection (CELIF) is a powerful tool for separation and sensitive determination of fluorescent species. Biologically active compounds, such as amino acids, peptides and proteins may exhibit native fluorescence, which is however often low and/or an expensive laser is required for excitation in UV. Therefore, labelling of the analytes with a fluorescent dye is usually necessary. In this work, a home-built CELIF instrument with diode pumped frequency-doubled continuous wave Nd:YAG excitation laser with feedback power regulation (532nm) was constructed. The suitability of this type of laser for LIF detection in a separation method was found excellent. A limit of detection (LOD) (S/N=3) of 2x10{sup -13}mol/l was achieved with rhodamine B, which is comparable to those obtained using similar instruments with Ar{sup +} laser [Y.F. Cheng, N.J. Dovichi, Science 242 (1988) 562, E.S. Yeung et al., J. Chromatogr. 608 (1992) 73]. LOD of a protein derivatized according to modified procedures [M.J. Little et al., Anal. Chim. Acta 339 (1997) 279, A. Chersi et al., Biochim. Biophys. Acta 1336 (1997) 83] was determined. Detection of the derivatives was found to be limited by insufficient reaction recovery at low analyte concentration, chemical noise, separation efficiency and quality of the derivatizing reagent rather than by the detector performance. As a consequence, a huge gap between the detection ability of CELIF instruments and LOD determined in real samples is revealed.

  16. Airborne differential absorption lidar for water vapour measurements in the upper troposphere and lower stratosphere in the spectral region around 940 nm

    Energy Technology Data Exchange (ETDEWEB)

    Poberaj, G.

    2000-07-01

    Two all-solid-state laser systems were developed and studied in detail to optimise their performance for an airborne water vapour differential absorption lidar (DIAL). Their special features are high average output powers and excellent spectral properties in the 940-nm spectral region relevant for monitoring very low water vapour contents in the upper troposphere and lower stratosphere. One system is an injection-seeded pulsed Ti:sapphire ring laser with a spectral bandwidth of 105 MHz and an average power of 1.1 W. The other system is an injection-seeded optical parametric oscillator (OPO) in a ring configuration. Using KTP as nonlinear crystal, a signal output with a spectral bandwidth of 140 MHz and an average power of 1.2 W was achieved. Both systems, the Ti:sapphire ring laser and the KTP OPO, possess spectral purity values higher than 99%. The pump source for these systems is a frequency doubled diode-pumped Nd:YAG laser operating at a repetition rate of 100 Hz. The KTP OPO system has been used as a transmitter in a new airborne water vapour DIAL instrument. For the first time, measurements of two-dimensional water vapour distributions with a high vertical (500 m) and horizontal (20 km) resolution across several potential vorticity streamers were performed. Very low water vapour mixing ratios (10-50 ppmv) and strong gradients were observed in the tropopause region. The sensitivity of the DIAL instrument in the centre of a stratospheric intrusion ranges from 3% in the near field to 12% in the far field (4 km). The first comparison experiments with in situ measuring instruments show a good agreement. Considerable differences are found between DIAL measurements and data obtained from the ECMWF operational analyses and a mesoscale numerical model. (orig.)

  17. An inductorless multi-mode RF front end for GNSS receiver in 55 nm CMOS

    Science.gov (United States)

    Yanbin, Luo; Chengyan, Ma; Yebing, Gan; Min, Qian; Tianchun, Ye

    2015-10-01

    An inductorless multi-mode RF front end for a global navigation satellite system (GNSS) receiver is presented. Unlike the traditional topology of a low noise amplifier (LNA), the inductorless current-mode noise-canceling LNA is applied in this design. The high-impedance-input radio frequency amplifier (RFA) further amplifies the GNSS signals and changes the single-end signal path into fully differential. The passive mixer down-converts the signals to the intermediate frequency (IF) band and conveys the signals to the analogue blocks. The local oscillator (LO) buffer divides the output frequency of the voltage controlled oscillator (VCO) and generates 25%-duty-cycle quadrature square waves to drive the mixer. Our measurement results display that the implemented RF front end achieves good overall performance while consuming only 6.7 mA from 1.2 V supply. The input return loss is better than -26 dB and the ultra low noise figure of 1.43 dB leads to high sensitivity of the GNSS receiver. The input 1 dB compression point is -43 dBm at the high gain of 48 dB. The designed circuit is fabricated in 55 nm CMOS technology and the die area, which is much smaller than traditional circuit, is around 220 × 280 μm2.

  18. Frequency adjustable MEMS vibration energy harvester

    Science.gov (United States)

    Podder, P.; Constantinou, P.; Amann, A.; Roy, S.

    2016-10-01

    Ambient mechanical vibrations offer an attractive solution for powering the wireless sensor nodes of the emerging “Internet-of-Things”. However, the wide-ranging variability of the ambient vibration frequencies pose a significant challenge to the efficient transduction of vibration into usable electrical energy. This work reports the development of a MEMS electromagnetic vibration energy harvester where the resonance frequency of the oscillator can be adjusted or tuned to adapt to the ambient vibrational frequency. Micro-fabricated silicon spring and double layer planar micro-coils along with sintered NdFeB micro-magnets are used to construct the electromagnetic transduction mechanism. Furthermore, another NdFeB magnet is adjustably assembled to induce variable magnetic interaction with the transducing magnet, leading to significant change in the spring stiffness and resonance frequency. Finite element analysis and numerical simulations exhibit substantial frequency tuning range (25% of natural resonance frequency) by appropriate adjustment of the repulsive magnetic interaction between the tuning and transducing magnet pair. This demonstrated method of frequency adjustment or tuning have potential applications in other MEMS vibration energy harvesters and micromechanical oscillators.

  19. Frequency adjustable MEMS vibration energy harvester

    International Nuclear Information System (INIS)

    Podder, P; Constantinou, P; Roy, S; Amann, A

    2016-01-01

    Ambient mechanical vibrations offer an attractive solution for powering the wireless sensor nodes of the emerging “Internet-of-Things”. However, the wide-ranging variability of the ambient vibration frequencies pose a significant challenge to the efficient transduction of vibration into usable electrical energy. This work reports the development of a MEMS electromagnetic vibration energy harvester where the resonance frequency of the oscillator can be adjusted or tuned to adapt to the ambient vibrational frequency. Micro-fabricated silicon spring and double layer planar micro-coils along with sintered NdFeB micro-magnets are used to construct the electromagnetic transduction mechanism. Furthermore, another NdFeB magnet is adjustably assembled to induce variable magnetic interaction with the transducing magnet, leading to significant change in the spring stiffness and resonance frequency. Finite element analysis and numerical simulations exhibit substantial frequency tuning range (25% of natural resonance frequency) by appropriate adjustment of the repulsive magnetic interaction between the tuning and transducing magnet pair. This demonstrated method of frequency adjustment or tuning have potential applications in other MEMS vibration energy harvesters and micromechanical oscillators. (paper)

  20. Control of Bouncing in MEMS Switches Using Double Electrodes

    KAUST Repository

    Abdul Rahim, Farhan

    2016-08-09

    This paper presents a novel way of controlling the bouncing phenomenon commonly present in the Radio Frequency Microelectromechanical Systems (RF MEMS) switches using a double-electrode configuration. The paper discusses modeling bouncing using both lumped parameter and beam models. The simulations of bouncing and its control are discussed. Comparison between the new proposed method and other available control techniques is also made. The Galerkin method is applied on the beam model accounting for the nonlinear electrostatic force, squeeze film damping, and surface contact effect. The results indicate that it is possible to reduce bouncing and hence beam degradation, by the use of double electrodes.

  1. BEAM-BEAM SIMULATIONS FOR DOUBLE-GAUSSIAN BEAMS.

    Energy Technology Data Exchange (ETDEWEB)

    MONTAG, C.; MALITSKY, N.; BEN-ZVI, I.; LITVINENKO, V.

    2005-05-16

    Electron cooling together with intra-beam scattering results in a transverse distribution that can best be described by a sum of two gaussians, one for the high-density core and one for the tails of the distribution. Simulation studies are being performed to understand the beam-beam interaction of these double-gaussian beams. Here we report the effect of low-frequency random tune modulations on diffusion in double-gaussian beams and compare the effects to those in beam-beam interactions with regular gaussian beams and identical tune shift parameters.

  2. BEAM-BEAM SIMULATIONS FOR DOUBLE-GAUSSIAN BEAMS

    International Nuclear Information System (INIS)

    MONTAG, C.; MALITSKY, N.; BEN-ZVI, I.; LITVINENKO, V.

    2005-01-01

    Electron cooling together with intra-beam scattering results in a transverse distribution that can best be described by a sum of two gaussians, one for the high-density core and one for the tails of the distribution. Simulation studies are being performed to understand the beam-beam interaction of these double-gaussian beams. Here we report the effect of loW--frequency random tune modulations on diffusion in double-gaussian beams and compare the effects to those in beam-beam interactions with regular gaussian beams and identical tune shift parameters

  3. Beam-Beam Simulations for Double-Gaussian Beams

    CERN Document Server

    Montag, Christoph; Litvinenko, Vladimir N; Malitsky, Nikolay

    2005-01-01

    Electron cooling together with intra-beam scattering results in a transverse distribution that can best be described by a sum of two Gaussians, one for the high-density core and one for the tails of the distribution. Simulation studies are being performed to understand the beam-beam interaction of these double-Gaussian beams. Here we report the effect of low-frequency random tune modulations on diffusion in double-Gaussian beams and compare the effects to those in beam-beam interactions with regular Gaussian beams and identical tuneshift parameters.

  4. Optical and solid state characterizaion of chemically deposited CuO/PbS double layer thin film

    Science.gov (United States)

    Chukwuemeka, Augustine; Nnabuchi Mishark, Nnamdi

    2018-02-01

    Optical and solid state characteristics of novel CuO/PbS double layer thin films were studied. Rutherford backscattering (RBS) technique deciphered the thicknesses of the films as 650 nm, 471 nm and 482 nm for as-deposited, annealed at 473 K and 673 K respectively. The XRD analysis depicts increase in grain size and peak intensity as temperature increases. The results of optical characterization show that thermal annealing has profound effects on all the optical and solid state parameters investigated. The absorbance increased with increase in temperature exhibiting maximum for the film annealed at 673 K. The transmittance of the film samples showed a decreasing trend with increase in temperature exhibiting minimum for the film annealed at 673 K. The absorption coefficient increases from 0.001 × 106 m‑1 to 0.006 × 106 m‑1 for as-deposited, 0.0025 × 106 m‑1 to 0.0175 × 106 m‑1 for the annealed at 473 K and 0.003 × 106 m‑1 to 0.020 × 106 m‑1 for the annealed at 673 K. The extinction coefficient increased with increased in temperature exhibiting a maximum for the film annealed at 673 K. The refractive index, real and imaginary dielectric constant do not have a trend with increase in annealing temperature. Increase in annealing temperature lowers the band gap from 4.13 eV for the as-deposited to 4.05 eV and 3.90 eV for the annealed at 473 K and 673 K respectively. The wide- bandgap materials permits devices to operate at much higher voltages, frequencies and temperatures than convection semiconductor materials. Thus, this film could be used for high power applications, light-emitting diodes, transducers and window layers for solar cell fabrication.

  5. Generation of five phase-locked harmonics by implementing a divide-by-three optical frequency divider.

    Science.gov (United States)

    Suhaimi, Nurul Sheeda; Ohae, Chiaki; Gavara, Trivikramarao; Nakagawa, Ken'ichi; Hong, Feng-Lei; Katsuragawa, Masayuki

    2015-12-15

    We report the generation of five phase-locked harmonics, f₁:2403  nm, f₂:1201  nm, f₃:801  nm, f₄:600  nm, and f₅:480  nm with an exact frequency ratio of 1:2:3:4:5 by implementing a divide-by-three optical frequency divider in the high harmonic generation process. All five harmonics are generated coaxially with high phase coherence in time and space, which are applicable for various practical uses.

  6. Vortex State in Sub-100 nm Magnetic Nanodots.

    Science.gov (United States)

    Roshchin, Igor V.

    2006-03-01

    Magnetism of nanostructured magnets, which size is comparable to or smaller than ferromagnetic domain size, offers a great potential for new physics. Detailed knowledge of magnetization reversal and possible magnetic configurations in magnetic nanostructures is essential for high-density magnetic memory. Many theoretical and experimental studies are focused on a magnetic vortex which in addition to a circular in-plane configuration of spins has a core, - the region with out-of-plane magnetization. We present a quantitative study of the magnetic vortex state and the vortex core in sub-100 nm magnetic dots. Arrays of single-layer and bilayer nanodots covering over 1 cm^2 are fabricated using self-assembled nanopores in anodized alumina. This method allows good control over the dot size and periodicity. Magnetization measurements performed using SQUID, VSM, and MOKE indicate a transition from a vortex to a single domain state for the Fe dots. This transition is studied as a function of the magnetic field and dots size. Micromagnetic and Monte Carlo simulations confirm the experimental observations. Thermal activation and exchange bias strongly affect the vortex nucleation field and have a much weaker effect on the vortex annihilation field. Direct imaging of magnetic moments in sub-100 nm dots is extremely difficult and has not been reported yet. Polarized grazing incidence small angle neutron scattering measurements allow dot imaging in reciprocal space. Quantitative analysis of such measurements performed on 65 nm Fe dots yields the vortex core size of ˜15 nm, in good agreement with the 14 nm obtained from the simulations. This work is done in collaboration with Chang-Peng Li, Zhi-Pan Li, S. Roy, S. K. Sinha, (UCSD), Xavier Batlle (U. Barcelona), R. K. Dumas, Kai Liu, (UC Davis), S. Park, R. Pynn, M. R. Fitzsimmons (LANL), J. Mejia Lopez (Pontificia U. Catolica de Chile), D. Altbir, (U. de Santiago de Chile), A. H. Romero (Cinvestav-Unidad Queretaro), and Ivan K

  7. Frequency dependence of sonophoresis.

    Science.gov (United States)

    Tezel, A; Sens, A; Tuchscherer, J; Mitragotri, S

    2001-12-01

    Application of low-frequency ultrasound has been shown to increase skin permeability, thereby facilitating delivery of macromolecules (low-frequency sonophoresis). In this study, we sought to determine the dependence of low-frequency sonophoresis on ultrasound frequency, intensity and energy density. Pig skin was exposed to low-frequency ultrasound over a range of ultrasound frequency and intensity conditions. The degree of skin permeabilization was measured using its conductivity. Imaging experiments were also carried out to visualize the transport pathways created by ultrasound. The data showed that for each frequency (in the range of 19.6-93.4 kHz), there exists a threshold intensity below which no detectable conductivity enhancement was observed. The threshold intensity increased with frequency. It is feasible to achieve the desired conductivity (permeability) enhancement regardless of the choice of frequency, although the necessary energy density is higher at higher frequencies. Low frequencies (approximately 20 kHz) induced localized transport compared to a more dispersed effect seen with higher frequencies (approximately 58.9 kHz). This study provides a quantitative understanding of the effects of low-frequency ultrasound on skin permeability.

  8. An investigation of the double layers caused by space vehicles moving through the ionosphere

    International Nuclear Information System (INIS)

    Liu Sanqiu; Liao Jingjing

    2010-01-01

    On the basis of non-steady-state nonlinear coupling equations of high-frequency field, density disturbance and potential, the evolution of double layers in the wake region of space vehicles moving through the ionosphere is numerically simulated in the non-static limit case. The results show that the interactions among plasmas, the vehicle and high-frequency electromagnetic waves radiated from the antenna system of the vehicle can lead to the formation of double layers. It is shown that the double layer is a nonlinear entity-caviton. Potential disturbance far away from the vehicle and the peak value of potential near the vehicle in the double layer are obvious. This is very important for detecting space vehicles with a stealth characteristic and preventing space vehicles from being harmed by double layers.

  9. Design and simulation of double annular illumination mode for microlithography

    Science.gov (United States)

    Song, Qiang; Zhu, Jing; Yang, Baoxi; Liu, Lei; Wang, Jun; Huang, Huijie

    2013-08-01

    Methods of generating various illumination patterns remain as an attractive and important micro-optics research area for the development of resolution enhancement in advanced lithography system. In the current illumination system of lithography machine, off-axis illumination is widely used as an effective approach to enhance the resolution and increase the depth of focus (DOF). This paper proposes a novel illumination mode generation unit, which transform conventional mode to double annular shaped radial polarized (DARP) mode for improving the resolution of micro-lithography. Through LightToolsTM software simulation, double annular shaped mode is obtained from the proposed generation unit. The mathematical expressions of the radius variation of inner and outer rings are deduced. The impacts of conventional and dual concentric annular illumination pattern on critical dimension uniformity were simulated on an isolated line, square hole and corner. Lithography performance was compared between DARP illumination mode and corresponding single annular modes under critical dimension of 45nm. As a result, DARP illumination mode can improve the uniformity of aerial image at 45nm node through pitch varied in 300-500 nm to a certain extent.

  10. A reflectivity profilometer for the optical characterisation of graded reflectivity mirrors in the 250 nm - 1100 nm spectral region

    International Nuclear Information System (INIS)

    Colucci, Alessandro; Nichelatti, Enrico

    1998-04-01

    It's developed the prototype of an instrument that can be used for the optical characterisation of graded reflectivity mirrors at any wavelength in the spectral region from 250 nm to 1100 nm. The instrument utilises a high-pressure Xe arc lamp as light source. Light is spectrally filtered by means of a grating monochromator. The sample is illuminated with an image of the monochromator exit slit. After reflection from the sample, this image is projected onto a 1024-elements charge-coupled device linear array driven by a digital frame board and interfaced with a personal computer. It's tested the instrument accuracy by comparing measurement results with the corresponding ones obtained by means of a laser scanning technique. Measurement Rms repeatability has been estimated to be approximately of 0.8% [it

  11. Combined fractional resurfacing (10600 nm/1540 nm): Tridimensional imaging evaluation of a new device for skin rejuvenation.

    Science.gov (United States)

    Mezzana, Paolo; Valeriani, Maurizio; Valeriani, Roberto

    2016-11-01

    In this study were described the results, by tridimensional imaging evaluation, of the new "Combined Fractional Resurfacing" technique with the first fractional laser that overtakes the limits of traditional ablative, nonablative fractional resurfacing by combining CO 2 ablative and GaAs nonablative lasers. These two wavelengths can work separately or in a mixed modality to give the best treatment choice to all the patients. In this study, it is demonstrated that the simultaneous combination of the CO 2 wavelength (10600 nm) and GaAs wavelength (1540 nm) reduced the downtime, reduced pain during the treatment, and produced better results on fine wrinkles reduction and almost the same results on pigmentation as seen with 3D analysis by Antera (Miravex).

  12. [Research on diagnosis of gas-liquid detonation exhaust based on double optical path absortion spectroscopy technique].

    Science.gov (United States)

    Lü, Xiao-Jing; Li, Ning; Weng, Chun-Sheng

    2014-03-01

    The effect detection of detonation exhaust can provide measurement data for exploring the formation mechanism of detonation, the promotion of detonation efficiency and the reduction of fuel waste. Based on tunable diode laser absorption spectroscopy technique combined with double optical path cross-correlation algorithm, the article raises the diagnosis method to realize the on-line testing of detonation exhaust velocity, temperature and H2O gas concentration. The double optical path testing system is designed and set up for the valveless pulse detonation engine with the diameter of 80 mm. By scanning H2O absorption lines of 1343nm with a high frequency of 50 kHz, the on-line detection of gas-liquid pulse detonation exhaust is realized. The results show that the optical testing system based on tunable diode laser absorption spectroscopy technique can capture the detailed characteristics of pulse detonation exhaust in the transient process of detonation. The duration of single detonation is 85 ms under laboratory conditions, among which supersonic injection time is 5.7 ms and subsonic injection time is 19.3 ms. The valveless pulse detonation engine used can work under frequency of 11 Hz. The velocity of detonation overflowing the detonation tube is 1,172 m x s(-1), the maximum temperature of detonation exhaust near the nozzle is 2 412 K. There is a transitory platform in the velocity curve as well as the temperature curve. H2O gas concentration changes between 0-7% during detonation under experimental conditions. The research can provide measurement data for the detonation process diagnosis and analysis, which is of significance to advance the detonation mechanism research and promote the research of pulse detonation engine control technology.

  13. Double Tracks closure report

    International Nuclear Information System (INIS)

    1997-06-01

    This report describes the remediation activities performed and the results of postremediation radiation surveys conducted at the Double Tracks site, located on Range 71 North, of the Nellis Air Force Range (NAFR) in southern Nevada. This remediation was conducted from June to August 1996 in accordance with the Interim Corrective Action Plan (ICAP) to remediate the site to an acceptable risk to human health and the environment. Soil with a total transuranic activity greater than 200 picoCuries per gram (pCi/g) was excavated, shipped to the Nevada Test Site (NTS), and disposed at the Area 3 Radioactive Waste Management Site (RWMS). A total of 52.3 grams of plutonium (Pu) with an activity of 5.12 Curies was disposed. The concrete pad at ground zero (GZ) was broken up, placed in a Sealand reg-sign container, and shipped to the NTS Area 6 decontamination pad. Additionally, approximately 10 m 3 (350 ft 3 ) of soil containing small chips of concrete was shipped to the NTS Area 6 decontamination pad. The concrete and soil/concrete mixture will be further characterized prior to disposal. At the time this report was written, characterization samples were being collected, with analytical results expected in January 1997. It is anticipated that the material will be disposed in mid-1997. This remediation is an interim action because final cleanup levels have not been established

  14. Double chambered right ventricle

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Chul Koo; Yu, Yun Jeong; Yeon, Kyung Mo; Han, Man Chung [Seoul National University College of Medicine, Seoul (Korea, Republic of)

    1983-12-15

    Fourteen cases of double chambered right ventricle were diagnosed angiographically and of these nine cases were confirmed after operation and autopsy at Seoul National University Hospital in recent four years since 1979. The clinical and radiological findings with the emphasis on the cinecardiographic findings were analysed. The summaries of the analysis are as follows: 1. Among 14 cases, 6 cases were male and 8 cases were female. Age distribution was from 4 years to 36 years. 2. In chest x-ray findings, pulmonary vascularity was increased in 8 cases, decreased in 4 cases, and normal in 2 cases. Cardiomegaly was observed in 8 cases and other showed normal heart size. 3. In cinecardiography, 11 cases had interventricular septal defect. Among these 11 cases, VSD located in proximal high pressure chamber was in 2 cases and located in distal low pressure chamber was in 9 cases. 4. The location of aberrant muscle bundle in sinus portion of right ventricle was in 8 cases. In the rest 6 cases, the aberrant muscle bundle was located below the infundibulum of right ventricle. 5. For accurate diagnosis and differential diagnosis with other congenital cardiac anomalies such as Tetralogy of Fallot or isolated pulmonic stenosis, biplane cineangiography and catheterization is an essential procedure.

  15. Double chambered right ventricle

    International Nuclear Information System (INIS)

    Cho, Chul Koo; Yu, Yun Jeong; Yeon, Kyung Mo; Han, Man Chung

    1983-01-01

    Fourteen cases of double chambered right ventricle were diagnosed angiographically and of these nine cases were confirmed after operation and autopsy at Seoul National University Hospital in recent four years since 1979. The clinical and radiological findings with the emphasis on the cinecardiographic findings were analysed. The summaries of the analysis are as follows: 1. Among 14 cases, 6 cases were male and 8 cases were female. Age distribution was from 4 years to 36 years. 2. In chest x-ray findings, pulmonary vascularity was increased in 8 cases, decreased in 4 cases, and normal in 2 cases. Cardiomegaly was observed in 8 cases and other showed normal heart size. 3. In cinecardiography, 11 cases had interventricular septal defect. Among these 11 cases, VSD located in proximal high pressure chamber was in 2 cases and located in distal low pressure chamber was in 9 cases. 4. The location of aberrant muscle bundle in sinus portion of right ventricle was in 8 cases. In the rest 6 cases, the aberrant muscle bundle was located below the infundibulum of right ventricle. 5. For accurate diagnosis and differential diagnosis with other congenital cardiac anomalies such as Tetralogy of Fallot or isolated pulmonic stenosis, biplane cineangiography and catheterization is an essential procedure

  16. Double mental foramina

    Directory of Open Access Journals (Sweden)

    Taruska Ventorini Vasconcelos

    Full Text Available The knowledge of the location, trajectory, and characteristics of the neurovascular bundles in the jaws is fundamental to reduce risk of injuries to this structure during surgical procedures, especially when anatomical variations are present. The presence of anatomical variations associated with the mental foramen has been reported in some cases and is frequently undervalued in clinical procedures. Sensorial disturbances, such as paresthesia in the lower lip or cheeks, may occur as result of pressure on the mental foramen. These anatomical variations can be detected in clinical practice by imaging exams. Computed tomography has been established as a valuable imaging modality capable of providing in-depth information about maxillofacial structures, allowing detailed evaluation of their topography and anatomical variations, such as additional mental foramina. The objective of this article was to describe a case with double mental foramina that only could be observed in computed tomography images. The use of cone beam computed tomography has increased in dentistry, thus anatomical variations that may have an influence on the diagnosis and treatment planning must be recognized. Have a good knowledge of additional mental foramina may contribute to adequate anesthetic techniques and to avoid misdiagnosis of bone lesions and eventual damages to the nerves and vessel during surgical procedures in that region.

  17. Antarctic radiation exposure doubles

    Science.gov (United States)

    Blue, Charles

    New data reveal that the Antarctic Peninsula received twice its normal maximum dose of hazardous solar ultraviolet radiation in December 1990. The prolonged persistence of the ozone hole over Antarctica caused an increased exposure of radiation, according to a paper published in the October issue of Geophysical Research Letters.John Frederick and Amy D. Alberts of the University of Chicago calculated the amount of ultraviolet solar spectral radiation from data collected at Palmer Station, Antarctica. During the spring of 1990 the largest observed values for ultraviolet radiation were approximately double the values expected, based on previous years. “The measurements from Palmer Station are consistent with similar data from McMurdo Sound, where a factor of three [ultraviolet radiation] enhancement was recorded, according to work by Knut Stamnes and colleagues at the University of Alaska,” Frederick said. “The radiation levels observed over Palmer Station in December 1990 may be the largest experienced in this region of the world since the development of the Earth's ozone layer,” he added.

  18. Lunch frequency among adolescents

    DEFF Research Database (Denmark)

    Pedersen, Trine Pagh; Holstein, Bjørn E; Krølner, Rikke

    2016-01-01

    OBJECTIVE: To investigate: (i) how lunch frequency of adolescents varies between schools and between classes within schools; (ii) the associations between frequency of lunch and individual sociodemographic factors and school characteristics; and (iii) if any observed associations between lunch...

  19. A reflectivity profilometer for the optical characterisation of grade reflectivity mirrors in the 250 nm - 1100 nm spectral region

    Energy Technology Data Exchange (ETDEWEB)

    Colucci, Alessandro; Nichelatti, Enrico [ENEA, Centro Ricerche Casaccia, Rome (Italy). Dipt. Innovazione

    1998-04-01

    It`s developed the prototype of an instrument that can be used for the optical characterisation of graded reflectivity mirrors at any wavelength in the spectral region from 250 nm to 1100 nm. The instrument utilises a high-pressure Xe arc lamp as light source. Light is spectrally filtered by means of a grating monochromator. The sample is illuminated with an image of the monochromator exit slit. After reflection from the sample, this image is projected onto a 1024-elements charge-coupled device linear array driven by a digital frame board and interfaced with a personal computer. It`s tested the instrument accuracy by comparing measurement results with the corresponding ones obtained by means of a laser scanning technique. Measurement Rms repeatability has been estimated to be approximately of 0.8%. [Italiano] E` stato sviluppato il prototipo di uno strumento per la catatterizzazione ottica di specchi a riflettivita` variabile, operante a qualsiasi lunghezza d`onda nell`intervallo spettrale da 250 nm a 1100 nm. La sorgente dello strumento e` una lampada ad arco allo Xenon ad alta pressione. La luce e` filtrata spettralmente per mezzo di un monocromatore a reticolo. Il campione viene illuminato da un`immagine della fenditura d`uscita del monocromatore. Dopo essere stata riflessa dal campione, questa immagine viene proiettata su un array CCD lineare a 1024 elementi, connesso elettronicamente a una scheda digitale e interfacciato a un personal computer. L`accuratezza dello strumento e` stata verificata confrontando alcune misure con le corrispondenti misure ottenute mediante una tecnica a scansione laser. La ripetibilita` RMS delle misure e` stata stimata essere circa dello 0.8%.

  20. Fast response dual frequency liquid crystal materials

    Science.gov (United States)

    Song, Qiong

    Dual frequency liquid crystal (DFLC) exhibits a positive dielectric anisotropy at low frequencies and negative dielectric anisotropy at high frequencies. The frequency where dielectric anisotropy is zero is called crossover frequency. DFLC can achieve fast rise time and fast decay time with the assistance of applied voltage. However, one drawback of DFLC is that it has dielectric heating effect when driven at a high frequency. Thus, the first part of this dissertation is to develop low crossover frequency DFLC materials. The dielectric relaxation and physical properties of some single- and double-ester compounds were investigated. Experimental results indicate that the double-ester compound exhibits a ˜3X lower dielectric relaxation frequencies and larger dielectric anisotropy than the single ester, but its viscosity is also higher. More generally, ten groups of dual frequency liquid crystals were compared in terms of dielectric relaxation frequency and dielectric anisotropy. The dielectric relaxation theory was discussed at last. To realize fast response time, high birefringence and low viscosity LC are required. From these two aspects, firstly four new high birefringence laterally difluoro phenyl tolane liquid crystals with a negative dielectric anisotropy were studied. These materials are used to enhance the birefringence of DFLC. They have a fairly small heat fusion enthalpy (˜3000 cal/mol) which improves their solubility in a host. We dope 10 wt% of each compound into a commercial negative mixture N1 and measured their birefringence, viscoelastic constant and figure of merit. Birefringence varies very little among homologues while viscoelastic constant increases as alkyl chain length increases. Secondly, we studied the effects of six diluters for lowering the viscosity while stabilizing the vertical alignment (VA) of the laterally difluoro terphenyl host mixture at elevated temperatures. The pros and cons of each diluter are analyzed. These lateral difluoro