Science.gov

Sample records for 6-12 mum wavelength

  1. Broadband carbon monoxide laser system operating in the wavelength range of 2.5 - 8.3 {mu}m

    SciTech Connect

    Andreev, Yu M; Ionin, Andrei A; Kinyaevsky, I O; Klimachev, Yu M; Kozlov, A Yu; Kotkov, A A; Lanskii, G V; Shaiduko, A V

    2013-02-28

    A two-cascade frequency conversion of CO-laser radiation is demonstrated in a single sample of a nonlinear ZnGeP{sub 2} crystal. The crystal is pumped by a repetitively pulsed cryogenic lowpressure CO laser operating on {approx}150 vibration - rotational transitions in the wavelength range 5.0 - 7.5 {mu}m, which corresponds to the frequency range of a half octave. In the first conversion cascade, generation of second harmonic and sum frequencies of various pairs of CO-laser radiation give {approx}350 emission lines in the wavelength range 2.5 - 3.7 {mu}m. In the second cascade, by mixing the radiation converted in the first cascade with the residual radiation of the CO laser we have obtained {approx}90 lines in the range 4.3 - 5.0 {mu}m and more than 80 lines in the range 7.5 - 8.3 {mu}m. Thus, using a single sample of the nonlinear ZnGeP{sub 2} crystal pumped by the radiation of a single CO laser we have produced a source of broadband (more than one and a half octaves) laser radiation, simultaneously operating at {approx}670 lines in the wavelength range 2.5 - 8.3 {mu}m. (lasers)

  2. Electroluminescence at a wavelength of 1.5 {mu}m in Si:Er/Si diode structures doped with Al, Ga, and B acceptors

    SciTech Connect

    Kuznetsov, V. P.; Shmagin, V. B.; Marychev, M. O.; Kudryavtsev, K. E.; Kuznetsov, M. V.; Andreev, B. A.; Kornaukhov, A. V.; Gorshkov, O. N.; Krasilnik, Z. F.

    2010-12-15

    Si:Er layers in diode structures were doped with Al, Ga, or B during growth by sublimation molecular-beam epitaxy. As a result, a sharp increase in the electroluminescence intensity at a wavelength of 1.5 {mu}m was observed in diodes with thick bases (as large as 0.8 {mu}m).

  3. Radiation resistance of nonlinear crystals at a wavelength of 9.55 {mu}m

    SciTech Connect

    Andreev, Yu M; Voevodin, V G; Badikov, Valerii V; Geiko, L G; Geiko, P P; Ivashchenko, M V; Karapuzikov, A I; Sherstov, I V

    2001-12-31

    The results of radiation resistance measurements for twelve nonlinear crystals are presented. The crystals include the well-known nonlinear CdGeAs{sub 2}, ZnGeP{sub 2}, AgGaSe{sub 2}, GaSe, AgGaS{sub 2}, and Ag{sub 3}AsS{sub 3} crystals operating in the middle IR range, new mixed AgGaGeS{sub 4} and Cd{sub 0.35}Hg{sub 0.65}Ga{sub 2}S{sub 4} crystals, two-phase (orange and yellow) HgGa{sub 2}S{sub 4} crystal, and the doped GaSe:In crystal. The mixed crystals and the two-phase HgGa{sub 2}S{sub 4} crystal are transparent in the range from 0.4 - 0.5 to 11.5 - 14.5 {mu}m. The measurements were performed using a pulsed single-mode highly stability TEA CO{sub 2} laser with an output pulse duration of {approx}30 ns. The damage thresholds of new nonlinear AgGaGeS{sub 4} and Cd {sub 0.35}Hg{sub 0.65}Ga{sub 2}S{sub 4} crystals and of the HgGa{sub 2}S{sub 4} crystal (the orange and yellow phases) were found to be 1.5 - 2.2 times higher than for the crystals operating in the middle IR range. (interaction of laser radiation with matter. laser plasma)

  4. Si:Er/Si diode structures for observing room-temperature electroluminescence at a wavelength of 1.54 {mu}m

    SciTech Connect

    Kuznetsov, V. P. Kuznetsov, M. V.; Krasil'nik, Z. F.

    2010-03-15

    Si:Er/Si diode structures for observing room-temperature electroluminescence at a wavelength of 1.5 {mu}m are analyzed. The structures were grown by sublimation molecular-beam epitaxy. Some ways to increase the electroluminescence intensity are discussed.

  5. Electroluminescence at a wavelength of 1.54 {mu}m in Si:Er/Si structures consisting of a number of p-n junctions

    SciTech Connect

    Kuznetsov, V. P.; Stepihova, M. V.; Shmagin, V. B.; Marychev, M. O.; Alyabina, N. A.; Kuznetsov, M. V.; Andreev, B. A.; Kornaukhov, A. V.; Gorshkov, O. N.; Krasilnik, Z. F.

    2011-11-15

    A method of connecting several p{sup +}-n junctions in the same Si:Er/Si structure is demonstrated; this method makes it possible to increase the electroluminescence intensity at a wavelength of 1.54 {mu}m. The structures have been grown by sublimation molecular-beam epitaxy.

  6. Frequency-resolved optical gating system with a tellurium crystal for characterizing free-electron lasers in the wavelength range of 10-30 {mu}m

    SciTech Connect

    Iijima, Hokuto; Nagai, Ryoji; Nishimori, Nobuyuki; Hajima, Ryoichi; Minehara, Eisuke J.

    2009-12-15

    A second-harmonic generation frequency-resolved optical gating (SHG-FROG) system has been developed for the complete characterization of laser pulses in the wavelength range of 10-30 {mu}m. A tellurium crystal is used so that spectrally resolved autocorrelation signals with a good signal-to-noise ratio are obtained. Pulses (wavelength {approx}22 {mu}m) generated from a free-electron laser are measured by the SHG-FROG system. The SHG intensity profile and the spectrum obtained by FROG measurements are well consistent with those of independent measurements of the pulse length and spectrum. The pulse duration and spectral width determined from the FROG trace are 0.6 ps and 5.2 THz at full width half maximum, respectively.

  7. Longitudinally diode-pumped 1.06-{mu}m Nd{sup 3+}:NaLa(MoO{sub 4}){sub 2} laser without pump-wavelength stabilisation

    SciTech Connect

    Zharikov, Evgeny V; Lis, Denis A; Subbotin, Kirill A; Ushakov, S N; Onishchenko, A M; Romanyuk, V A; Shestakov, A V

    2006-01-31

    The spectral and lasing characteristics of a Nd{sup 3+}:NaLa(MoO{sub 4}){sub 2} crystal longitudinally diode-pumped without pump-wavelength stabilisation are studied. A variation in the output power did not exceed 30% when the pump wavelength was changed in the spectral region from 0.794 to 0.811 {mu}m. (lasers)

  8. THE HUBBLE SPACE TELESCOPE WIDE FIELD CAMERA 3 EARLY RELEASE SCIENCE DATA: PANCHROMATIC FAINT OBJECT COUNTS FOR 0.2-2 {mu}m WAVELENGTH

    SciTech Connect

    Windhorst, Rogier A.; Cohen, Seth H.; Mechtley, Matt; Rutkowski, Michael J.; Hathi, Nimish P.; McCarthy, Patrick J.; Seibert, Mark; Ryan, Russell E. Jr; Yan Haojing; Baldry, Ivan K.; Driver, Simon P.; Hill, David T.; Kelvin, Lee S.; Robotham, Aaron S. G.; Frogel, Jay A.; Koekemoer, Anton M.; O'Connell, Robert W.; Straughn, Amber N.; Tuffs, Richard J.; Balick, Bruce

    2011-04-01

    We describe the Hubble Space Telescope (HST) Wide Field Camera 3 (WFC3) Early Release Science (ERS) observations in the Great Observatories Origins Deep Survey (GOODS) South field. The new WFC3 ERS data provide calibrated, drizzled mosaics in the UV filters F225W, F275W, and F336W, as well as in the near-IR filters F098M (Y{sub s} ), F125W (J), and F160W (H) with 1-2 HST orbits per filter. Together with the existing HST Advanced Camera for Surveys (ACS) GOODS-South mosaics in the BViz filters, these panchromatic 10-band ERS data cover 40-50 arcmin{sup 2} at 0.2-1.7 {mu}m in wavelength at 0.''07-0.''15 FWHM resolution and 0.''090 Multidrizzled pixels to depths of AB {approx_equal} 26.0-27.0 mag (5{sigma}) for point sources, and AB {approx_equal} 25.5-26.5 mag for compact galaxies. In this paper, we describe (1) the scientific rationale, and the data taking plus reduction procedures of the panchromatic 10-band ERS mosaics, (2) the procedure of generating object catalogs across the 10 different ERS filters, and the specific star-galaxy separation techniques used, and (3) the reliability and completeness of the object catalogs from the WFC3 ERS mosaics. The excellent 0.''07-0.''15 FWHM resolution of HST/WFC3 and ACS makes star-galaxy separation straightforward over a factor of 10 in wavelength to AB {approx_equal} 25-26 mag from the UV to the near-IR, respectively. Our main results are: (1) proper motion of faint ERS stars is detected over 6 years at 3.06 {+-} 0.66 mas year{sup -1} (4.6{sigma}), consistent with Galactic structure models; (2) both the Galactic star counts and the galaxy counts show mild but significant trends of decreasing count slopes from the mid-UV to the near-IR over a factor of 10 in wavelength; (3) combining the 10-band ERS counts with the panchromatic Galaxy and Mass Assembly survey counts at the bright end (10 mag {approx}< AB {approx}< 20 mag) and the Hubble Ultra Deep Field counts in the BVizY{sub s}JH filters at the faint end (24 mag {approx

  9. Terahertz generation and power limits in In{sub 0.53}Ga{sub 0.47}As photomixer coupled to transverse-electromagnetic-horn antenna driven at 1.55 {mu}m wavelengths

    SciTech Connect

    Mangeney, J.; Meng, F.; Gacemi, D.; Peytavit, E.; Lampin, J. F.; Akalin, T.

    2010-10-18

    We report continuous wave generation at frequencies up to 2 THz using ion-irradiated In{sub 0.53}Ga{sub 0.47}As photomixers coupled to transverse-electromagnetic-horn antennae driven at {approx}1.55 {mu}m wavelength. Output powers up to 0.1 {mu}W at 700 GHz have been achieved. The dependence of the output power on incident optical power and the bias voltage is analyzed in the both regimes of Ohmic transport and recombination-limited transport. The fundamental limitations of the performance of the photomixer devices based on photoconductive phenomenon in recombination-limited transport are analyzed.

  10. Measurement of optical absorption in polycrystalline CVD diamond plates by the phase photothermal method at a wavelength of 10.6 {mu}m

    SciTech Connect

    Luk'yanov, A Yu; Serdtsev, E V; Volkov, P V; Ral'chenko, Viktor G; Savel'ev, A V; Konov, Vitalii I; Khomich, A V

    2008-12-31

    A highly-efficient phase photothermal method is developed for quantitative measurements of the small optical absorption coefficient in thin plates made of highly transparent materials in which bulk losses significantly exceed surface losses. The bulk absorption coefficient at 10.6 {mu}m is estimated in polycrystalline diamond plates grown from the vapour phase (a CVD diamond). The results are compared with those for natural and synthetic diamond single crystals and with the concentrations of nitrogen and hydrogen impurities. The absorption coefficient of the best samples of the CVD diamond did not exceed 0.06 cm{sup -1}, which, taking into account the high thermal conductivity of the CVD diamond (1800-2200 W mK{sup -1} at room temperature), makes this material attractive for fabricating output windows of high-power CO{sub 2} lasers, especially for manufacturing large-size optics. (laser applications and other topics in quantum electronics)

  11. Long wavelength (>1.55 {mu}m) room temperature emission and anomalous structural properties of InAs/GaAs quantum dots obtained by conversion of In nanocrystals

    SciTech Connect

    Urbanczyk, A.; Keizer, J. G.; Koenraad, P. M.; Noetzel, R.

    2013-02-18

    We demonstrate that molecular beam epitaxy-grown InAs quantum dots (QDs) on (100) GaAs obtained by conversion of In nanocrystals enable long wavelength emission in the InAs/GaAs material system. At room temperature they exhibit a broad photoluminescence band that extends well beyond 1.55 {mu}m. We correlate this finding with cross-sectional scanning tunneling microscopy measurements. They reveal that the QDs are composed of pure InAs which is in agreement with their long-wavelength emission. Additionally, the measurements reveal that the QDs have an anomalously undulated top surface which is very different to that observed for Stranski-Krastanow grown QDs.

  12. Generation of 2. 5-ps light pulses with 15-nm wavelength tunability at 1. 3 [mu]m by a self-seeded gain-switched semiconductor laser

    SciTech Connect

    Schell, M.; Huhse, D.; Bimberg, D. . Inst. fuer Festkoerperphysik)

    1993-11-01

    The authors demonstrate the generation of 2.5-ps pulsed by a Fabry-Perot semiconductor laser with 15-nm wavelength tunability. A commercial laser is switched to single longitudinal mode pulse emission by self-seeding, using an external grating. The sidemode suppression ratio is better than 15 dB, with a peak value of 21 dB. The linearly red chirped pulses are compressed from 21--30 ps to 2.5--3.5 ps in a dispersion-shifted fiber. The simple experimental setup consists of a fiber coupler, a grating, and the dispersion-shifted fiber.

  13. MULTI-WAVELENGTH STUDY OF A COMPLETE IRAC 3.6 {mu}m SELECTED GALAXY SAMPLE: A FAIR CENSUS OF RED AND BLUE POPULATIONS AT REDSHIFTS 0.4-1.2

    SciTech Connect

    Huang, J.-S.; Faber, S. M.; Koo, D.; Rigopoulou, D.; Magdis, G.; Newman, J.; Shu, C.; Luo, Z.; Ashby, M. L. N.; Wang, T.; Willner, S. P.; Fazio, G. G.; Barmby, P.; Coil, A.; Zheng, X. Z.

    2013-03-20

    We present a multi-wavelength study of a 3.6 {mu}m selected galaxy sample in the Extended Groth Strip (EGS). The sample is complete for galaxies with stellar mass >10{sup 9.5} M{sub Sun} and redshift 0.4 < z < 1.2. In this redshift range, the Infrared Array Camera 3.6 {mu}m band measures the rest-frame near-infrared band, permitting nearly unbiased selection with respect to both quiescent and star-forming galaxies. The numerous spectroscopic redshifts available in the EGS are used to train an artificial neural network to estimate photometric redshifts. The distribution of photometric redshift errors is Gaussian with standard deviation {approx}0.025(1 + z), and the fraction of redshift failures (>3{sigma} errors) is about 3.5%. A new method of validation based on pair statistics confirms the estimate of standard deviation even for galaxies lacking spectroscopic redshifts. Basic galaxy properties measured include rest-frame U - B colors, B- and K-band absolute magnitudes, and stellar masses. We divide the sample into quiescent and star-forming galaxies according to their rest-frame U - B colors and 24-3.6 {mu}m flux density ratios and derive rest K-band luminosity functions and stellar mass functions for quiescent, star-forming, and all galaxies. The results show that massive, quiescent galaxies were in place by z Almost-Equal-To 1, but lower mass galaxies generally ceased their star formation at later epochs.

  14. SURVEY OF NEARBY FGK STARS AT 160 mum WITH SPITZER

    SciTech Connect

    Tanner, Angelle; Beichman, Charles; Bryden, Geoff; Lisse, Carey

    2009-10-10

    The Spitzer Space Telescope has advanced debris disk science tremendously with a wealth of information on debris disks around nearby A, F, G, K, and M stars at 24 and 70 mum with the MIPS photometer and at 8-34 mum with IRS. Here we present 160 mum observations of a small subset of these stars. At this wavelength, the stellar photospheric emission is negligible and any detected emission corresponds to cold dust in extended Kuiper Belt analogs. However, the Spitzer 160 mum observations are limited in sensitivity by the large beam size which results in significant 'noise' due to cirrus and extragalactic confusion. In addition, the 160 mum measurements suffer from the added complication of a light leak next to the star's position whose flux is proportional to the near-infrared flux of the star. We are able to remove the contamination from the leak and report 160 mum measurements or upper limits for 24 stars. Three stars (HD 10647, HD 207129, and HD 115617) have excesses at 160 mum that we use to constrain the properties of the debris disks around them. A more detailed model of the spectral energy distribution of HD 10647 reveals that the 70 and 160 mum emission could be due to small water ice particles at a distance of 100 AU, consistent with Hubble Space Telescope optical imaging of circumstellar material in the system.

  15. SUBMILLIMETER POLARIZATION OF GALACTIC CLOUDS: A COMPARISON OF 350 {mu}m AND 850 {mu}m DATA

    SciTech Connect

    Vaillancourt, John E.; Matthews, Brenda C. E-mail: brenda.matthews@nrc-cnrc.gc.ca

    2012-08-01

    The Hertz and SCUBA polarimeters, working at 350 {mu}m and 850 {mu}m, respectively, have measured the polarized emission in scores of Galactic clouds. Of the clouds in each data set, 17 were mapped by both instruments with good polarization signal-to-noise ratios. We present maps of each of these 17 clouds comparing the dual-wavelength polarization amplitudes and position angles at the same spatial locations. In total number of clouds compared, this is a four-fold increase over previous work. Across the entire data set real position angle differences are seen between wavelengths. While the distribution of {phi}(850)-{phi}(350) is centered near zero (near-equal angles), 64% of data points with high polarization signal-to-noise (P {>=} 3{sigma}{sub p}) have |{phi}(850)-{phi}(350)| > 10 Degree-Sign . Of those data with small changes in position angle ({<=}10 Degree-Sign ) the median ratio of the polarization amplitudes is P(850)/P(350) = 1.7 {+-} 0.6. This value is consistent with previous work performed on smaller samples and models that require mixtures of different grain properties and polarization efficiencies. Along with the polarization data we have also compiled the intensity data at both wavelengths; we find a trend of decreasing polarization with increasing 850-to-350 {mu}m intensity ratio. All the polarization and intensity data presented here (1699 points in total) are available in electronic format.

  16. 46 CFR 12.01-6-12.01-7 - [Reserved

    Code of Federal Regulations, 2010 CFR

    2010-10-01

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  17. Infrared (10.6-mum) scattering and extinction in laboratory water and ice clouds.

    PubMed

    Sassen, K

    1981-01-15

    Measurements of the angular scattering and extinction of IR (10.6-mum) laser radiation in laboratory water and ice clouds are reported and compared to theoretical predictions for spheres and visible (0.633-mum) light scattering data. Randomly oriented cloud particles with dimensions ranging from several times smaller to larger than the incident wavelength generated phase functions span the Rayleigh and Mie scattering domains and illustrate the effects caused by strong internal energy absorption. Dual-wavelength extinction measurements reveal information on the growth and dissipation of laboratory water clouds and the effects of cloud seeding. The remote sensing significance of the findings is discussed.

  18. Continuously tunable, 6{endash}14 {mu}m silver-gallium selenide optical parametric oscillator pumped at 1.57 {mu}m

    SciTech Connect

    Chandra, S.; Allik, T.H.; Catella, G.; Utano, R.; Hutchinson, J.A.

    1997-08-01

    An angle tuned silver gallium selenide (AgGaSe{sub 2}) optical parametric oscillator (OPO), pumped by the fixed wavelength 1.57 {mu}m output of a noncritically phase-matched KTiOPO{sub 4} OPO, yielded radiation continuously tunable from 6 to 14 {mu}m. Energies of up to 1.2 mJ/pulse with bandwidths of {approximately}5cm{sup {minus}1} (full width at half-maximum) were obtained using a 6.5{times}6.5{times}35.3mm long, type I AgGaSe{sub 2} crystal. {copyright} {ital 1997 American Institute of Physics.}

  19. MUM1/IRF4: A Review.

    PubMed

    Gualco, Gabriela; Weiss, Lawrence M; Bacchi, Carlos E

    2010-07-01

    MUM1/IRF4 protein is a member of the interferon regulatory factor (IRF) family of transcriptional factors initially described as downstream regulators of interferon signaling. The quantity of this factor varies within the hematopoietic system in a lineage and stage-specific way. It is considered to be a key regulator of several steps in lymphoid, myeloid, and dendritic cell differentiation and maturation. MUM1/IRF4 expression is observed in many lymphoid and myeloid malignancies, and may be a promising target for the treatment of some of these neoplasms. We reviewed the literature on MUM1/IRF4, with emphasis on the pathologic aspects of this marker in reactive and malignant hematologic and nonhematologic conditions.

  20. ON THE 10 mum SILICATE FEATURE IN ACTIVE GALACTIC NUCLEI

    SciTech Connect

    Nikutta, Robert; Elitzur, Moshe; Lacy, Mark E-mail: moshe@pa.uky.ed

    2009-12-20

    The 10 mum silicate feature observed with Spitzer in active galactic nuclei (AGNs) reveals some puzzling behavior. It (1) has been detected in emission in type 2 sources, (2) shows broad, flat-topped emission peaks shifted toward long wavelengths in several type 1 sources, and (3) is not seen in deep absorption in any source observed so far. We solve all three puzzles with our clumpy dust radiative transfer formalism. Addressing (1), we present the spectral energy distribution (SED) of SST1721+6012, the first type 2 quasar observed to show a clear 10 mum silicate feature in emission. Such emission arises in models of the AGN torus easily when its clumpy nature is taken into account. We constructed a large database of clumpy torus models and performed extensive fitting of the observed SED. We find that the cloud radial distribution varies as r {sup -1.5} and the torus contains 2-4 clouds along radial equatorial rays, each with optical depth at visual approx60-80. The source bolometric luminosity is approx3 x 10{sup 12} L{sub sun}. Our modeling suggests that approx<35% of objects with tori sharing these characteristics and geometry would have their central engines obscured. This relatively low obscuration probability can explain the clear appearance of the 10 mum emission feature in SST1721+6012 together with its rarity among other QSO2. Investigating (2), we also fitted the SED of PG1211+143, one of the first type 1 QSOs with a 10 mum silicate feature detected in emission. Together with other similar sources, this QSO appears to display an unusually broadened feature whose peak is shifted toward longer wavelengths. Although this led to suggestions of non-standard dust chemistry in these sources, our analysis fits such SEDs with standard galactic dust; the apparent peak shifts arise from simple radiative transfer effects. Regarding (3), we find additionally that the distribution of silicate feature strengths among clumpy torus models closely resembles the observed

  1. A 205 {mu}m [N II] MAP OF THE CARINA NEBULA

    SciTech Connect

    Oberst, T. E.; Parshley, S. C.; Nikola, T.; Stacey, G. J.; Loehr, A.; Lane, A. P.; Stark, A. A.; Kamenetzky, J.

    2011-10-01

    We present the results of a {approx}250 arcmin{sup 2} mapping of the 205 {mu}m [N II] fine-structure emission over the northern Carina Nebula, including the Car I and Car II H II regions. Spectra were obtained using the South Pole Imaging Fabry-Perot Interferometer (SPIFI) at the Antarctic Submillimeter Telescope and Remote Observatory (AST/RO) at the South Pole. We supplement the 205 {mu}m data with new reductions of far-IR fine-structure spectra from the Infrared Space Observatory (ISO) Long Wavelength Spectrometer (LWS) in 63 {mu}m [O I], 122 {mu}m [N II], 146 {mu}m [O I], and 158 {mu}m [C II]; the 146 {mu}m [O I] data include 90 raster positions which have not been previously published. Morphological comparisons are made with optical, radio continuum, and CO maps. The 122/205 line ratio is used to probe the density of the low-ionization gas, and the 158/205 line ratio is used to probe the fraction of C{sup +} arising from photodissociation regions (PDRs). The [O I] and [C II] lines are used to construct a PDR model of Carina. When the PDR properties are compared with other sources, Carina is found to be more akin to 30 Doradus than galactic star-forming regions such as Orion, M17, or W49; this is consistent with the view of Carina as a more evolved region, where much of the parent molecular cloud has been ionized or swept away. These data constitute the first ground-based detection of the 205 {mu}m [N II] line, and the third detection overall since those of COBE FIRAS and the Kuiper Airborne Observatory in the early 1990s.

  2. ULTRA DEEP AKARI OBSERVATIONS OF ABELL 2218: RESOLVING THE 15 {mu}m EXTRAGALACTIC BACKGROUND LIGHT

    SciTech Connect

    Hopwood, R.; Serjeant, S.; Negrello, M.; Pearson, C.; Egami, E.; Im, M.; Ko, J.; Lee, H. M.; Lee, M. G.; Kneib, J.-P.; Matsuhara, H.; Nakagawa, T.; Takagi, T.; Smail, I.

    2010-06-10

    We present extragalactic number counts and a lower limit estimate for the cosmic infrared background (CIRB) at 15 {mu}m from AKARI ultra deep mapping of the gravitational lensing cluster Abell 2218. These data are the deepest taken by any facility at this wavelength and uniquely sample the normal galaxy population. We have de-blended our sources, to resolve photometric confusion, and de-lensed our photometry to probe beyond AKARI's blank-field sensitivity. We estimate a de-blended 5{sigma} sensitivity of 28.7 {mu}Jy. The resulting 15 {mu}m galaxy number counts are a factor of 3 fainter than previous results, extending to a depth of {approx} 0.01 mJy and providing a stronger lower limit constraint on the CIRB at 15 {mu}m of 1.9 {+-} 0.5 nW m{sup -2} sr{sup -1}.

  3. Using a Checking Account. Grades 6-12.

    ERIC Educational Resources Information Center

    Trey, Frances

    Instructions and exercises on the use of checking accounts are provided for students in grades 6-12. The following topics are included: (1) reasons for opening a checking account; (2) how to open a checking account; (3) how to fill out deposit slips; (4) the elements of a check and how to write a check correctly; (5) checking account rules; (6)…

  4. Parallel Curriculum Units for Science, Grades 6-12

    ERIC Educational Resources Information Center

    Leppien, Jann H.; Purcell, Jeanne H.

    2011-01-01

    Based on the best-selling book "The Parallel Curriculum", this professional development resource gives multifaceted examples of rigorous learning opportunities for science students in Grades 6-12. The four sample units revolve around genetics, the convergence of science and society, the integration of language arts and biology, and the periodic…

  5. Home Economics/Health Grades 6-12. Program Evaluation.

    ERIC Educational Resources Information Center

    Des Moines Public Schools, IA. Teaching and Learning Div.

    Home economics programs are offered to students in grades 6-12 in the Des Moines INdependent Community School District (Iowa). Programs at the middle school level are exploratory, leading to occupational training in family and consumer science, child care, food service, and textile and fashion arts at the high school level. Health education…

  6. Comparison of laser-induced breakdown spectra of organic compounds with irradiation at 1.5 and 1.064 {mu}m

    SciTech Connect

    Wong, Diane M.; Dagdigian, Paul J

    2008-11-01

    A comprehensive investigation of laser-induced breakdown spectroscopy (LIBS) at 1.500 {mu}m of residues of six organic compounds (anthracene, caffeine, glucose, 1,3-dinitrobenzene, 2,4-dinitrophenol, and 2,4-dinitrotoluene) on aluminum substrates is presented and compared with LIBS at the Nd:YAG fundamental wavelength of 1.064 {mu}m. The overall emission intensities were found to be smaller at 1.500 {mu}m than at 1.064 {mu}m, and the ratios of C2 and CN molecular emissions to the H atomic emissions were observed to be less. Possible reasons for the observed differences in LIBS at 1.064 {mu}m versus 1.500 {mu}m are discussed.

  7. FIRST SCIENCE OBSERVATIONS WITH SOFIA/FORCAST: 6-37 {mu}m IMAGING OF ORION BN/KL

    SciTech Connect

    De Buizer, James M.; Becklin, E. E.; Zinnecker, Hans; Shuping, Ralph Y.; Vacca, William D.; Morris, Mark R.; Herter, Terry L.; Adams, Joseph D.

    2012-04-20

    The Becklin-Neugebauer/Kleinmann-Low (BN/KL) region of the Orion Nebula is the nearest region of high-mass star formation in our galaxy. As such, it has been the subject of intense investigation at a variety of wavelengths, which have revealed it to be brightest in the infrared to submillimeter wavelength regime. Using the newly commissioned SOFIA airborne telescope and its 5-40 {mu}m camera FORCAST, images of the entire BN/KL complex have been acquired. The 31.5 and 37.1 {mu}m images represent the highest resolution observations ({approx}<4'') ever obtained of this region at these wavelengths. These observations reveal that the BN object is not the dominant brightness source in the complex at wavelengths {>=} 31.5 {mu}m and that this distinction goes instead to the source IRc4. It was determined from these images and derived dust color temperature maps that IRc4 is also likely to be self-luminous. A new source of emission has also been identified at wavelengths {>=} 31.5 {mu}m that coincides with the northeastern outflow lobe from the protostellar disk associated with radio source I.

  8. Announcement: Sleep Awareness Week - March 6-12, 2016.

    PubMed

    2016-03-01

    Sleep Awareness Week, the National Sleep Foundation's annual campaign to educate the public about the importance of sleep in health and safety, will be observed March 6-12, 2016. The American Academy of Sleep Medicine and the Sleep Research Society recommend that adults aged 18-60 years sleep ≥7 hours each night to promote optimal health and well-being. However, 35% of U.S. adults report typically sleeping <7 hours Adults who do not get enough sleep on a regular basis are more likely to suffer from chronic conditions, such as obesity, high blood pressure, diabetes, and poor mental health.

  9. A Redox Economical Synthesis of Bioactive 6,12-Guaianolides

    PubMed Central

    Wen, Bo; Hexum, Joseph K.; Widen, John C.

    2013-01-01

    Syntheses of two 6,12-guaianolide analogs are reported within. The scope of the tandem allylboration/lactonization chemistry is expanded to provide a functionalized alleneyne-containing α-methylene butyrolactone that undergoes a Rh(I)-catalyzed cyclocarbonylation reaction to afford a 5-7-5 ring system. The resulting cycloadducts bear a structural resemblance to other NF-κB inhibitors such as cumambrin A and indeed were shown to inhibit NF-κB signaling and cancer cell growth. PMID:23662902

  10. MBE growth and characterization of 5-{mu}m quantum-cascade lasers

    SciTech Connect

    Mamutin, V. V. Ustinov, V. M.; Boetthcher, J.; Kuenzel, H.

    2010-07-15

    Quantum-cascade lasers, which are obtained by molecular-beam epitaxy, emit at wavelengths of 5.0 {mu}m at 77 K and 5.2 {mu}m at 300 K and are based on a design with four quantum wells in the active region with vertical transitions and strain-compensated superlattices with high-efficiency injection and a short lifetime of the ground state are fabricated. The typical thresholds for lasing at 300 K were in the range 4-10 kA/cm{sup 2}. The maximum emission power was as high as {approx}1 W, the maximum lasing temperature was {approx}450 K, and the maximum characteristic temperature T{sub 0} {approx} 200 K. The use of a modified process of postgrowth treatment made it possible to reproducibly obtain high-quality devices.

  11. Diode-pumped Tm : Sc{sub 2}SiO{sub 5} laser ({lambda} = 1.98 {mu}m)

    SciTech Connect

    Zavartsev, Yu D; Zagumennyi, A I; Kalachev, Yu L; Kutovoi, S A; Mikhailov, Viktor A; Podreshetnikov, V V; Shcherbakov, Ivan A

    2011-05-31

    Lasing at a wavelength of 1.98 {mu}m is obtained for the first time in a diode-pumped ({lambda} = 792 {mu}m) active element made of a Tm{sup 3+}: Sc{sub 2}SiO{sub 5} crystal grown by the Czochralski method. The laser slope efficiency reached 18.7% at the output power up to 520 mW. (lasers)

  12. Transmission at lambda = 10.6-mum wavelength through the upper atmosphere.

    PubMed

    Douglas-Hamilton, D H

    1978-08-01

    An analytic model of atmospheric bleaching at 10.6 umicrom is derived from analysis of the kinetic equations for the CO(2)-N(2)-H(2)O system. The case of upward-directed CO(2) laser beams is of particular interest, and values of local absorptance and total absorption integrated along beam path are given. At intensities 10(6)-10(7) W cm(-2) thermal blooming of the laser beam is greatly reduced due to bleached absorption.

  13. Continuous and discrete wavelength tuning in Er:Yb fiber Fabry--Perot lasers

    SciTech Connect

    Hsu, K.; Miller, C.M.; Kringlebotn, J.T.; Payne, D.N.

    1995-02-15

    Continuous and discrete single-frequency tuning in the 1.5-{mu}m wavelength region are demonstrated by incorporation of erbium:ytterbium phosphosilicate fibers in single and compound fiber Fabry--Perot cavity configurations. Continuous wavelength tuning was obtained over 3.3 nm in a single-cavity laser of 218-{mu}m cavity length. Discrete wavelength tuning was achieved over 9.59 nm in a compound-cavity laser having a 2-mm gain section.

  14. Optical amplification at the 1. 31 wavelength

    DOEpatents

    Cockroft, N.J.

    1994-02-15

    An optical amplifier operating at the 1.31 [mu]m wavelength for use in such applications as telecommunications, cable television, and computer systems is described. An optical fiber or other waveguide device is doped with both Tm[sup 3+] and Pr[sup 3+] ions. When pumped by a diode laser operating at a wavelength of 785 nm, energy is transferred from the Tm[sup 3+] ions to the Pr[sup 3+] ions, causing the Pr[sup 3+] ions to amplify at a wavelength of 1.31. 1 figure.

  15. 40 CFR 721.524 - Alcohols, C6-12, ethoxylated, reaction product with maleic anhydride.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Alcohols, C6-12, ethoxylated, reaction... New Uses for Specific Chemical Substances § 721.524 Alcohols, C6-12, ethoxylated, reaction product... chemical substance identified generically as alcohols, C6-12, ethoxylated, reaction product with...

  16. 40 CFR 721.524 - Alcohols, C6-12, ethoxylated, reaction product with maleic anhydride.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Alcohols, C6-12, ethoxylated, reaction... New Uses for Specific Chemical Substances § 721.524 Alcohols, C6-12, ethoxylated, reaction product... chemical substance identified generically as alcohols, C6-12, ethoxylated, reaction product with...

  17. 40 CFR 721.524 - Alcohols, C6-12, ethoxylated, reaction product with maleic anhydride.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Alcohols, C6-12, ethoxylated, reaction... New Uses for Specific Chemical Substances § 721.524 Alcohols, C6-12, ethoxylated, reaction product... chemical substance identified generically as alcohols, C6-12, ethoxylated, reaction product with...

  18. 40 CFR 721.524 - Alcohols, C6-12, ethoxylated, reaction product with maleic anhydride.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Alcohols, C6-12, ethoxylated, reaction... New Uses for Specific Chemical Substances § 721.524 Alcohols, C6-12, ethoxylated, reaction product... chemical substance identified generically as alcohols, C6-12, ethoxylated, reaction product with...

  19. 40 CFR 721.524 - Alcohols, C6-12, ethoxylated, reaction product with maleic anhydride.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Alcohols, C6-12, ethoxylated, reaction... New Uses for Specific Chemical Substances § 721.524 Alcohols, C6-12, ethoxylated, reaction product... chemical substance identified generically as alcohols, C6-12, ethoxylated, reaction product with...

  20. Reflective optical imaging system for extreme ultraviolet wavelengths

    DOEpatents

    Viswanathan, V.K.; Newnam, B.E.

    1993-05-18

    A projection reflection optical system has two mirrors in a coaxial, four reflection configuration to reproduce the image of an object. The mirrors have spherical reflection surfaces to provide a very high resolution of object feature wavelengths less than 200 [mu]m, and preferably less than 100 [mu]m. An image resolution of features less than 0.05-0.1 [mu]m, is obtained over a large area field; i.e., 25.4 mm [times] 25.4 mm, with a distortion less than 0.1 of the resolution over the image field.

  1. Reflective optical imaging system for extreme ultraviolet wavelengths

    DOEpatents

    Viswanathan, Vriddhachalam K.; Newnam, Brian E.

    1993-01-01

    A projection reflection optical system has two mirrors in a coaxial, four reflection configuration to reproduce the image of an object. The mirrors have spherical reflection surfaces to provide a very high resolution of object feature wavelengths less than 200 .mu.m, and preferably less than 100 .mu.m. An image resolution of features less than 0.05-0.1 .mu.m, is obtained over a large area field; i.e., 25.4 mm .times.25.4 mm, with a distortion less than 0.1 of the resolution over the image field.

  2. Reflective optical imaging system for extreme ultraviolet wavelengths

    SciTech Connect

    Viswanathan, V.K.; Newnam, B.E.

    1991-12-31

    This invention is comprised of a projection reflection optical system having two mirrors in a coaxial, four reflection configuration to reproduce the image of an object. The mirrors have aspherical reflection surfaces to provide a very high resolution of object feature wavelengths less than 200 {mu}m, and preferably less than 100 {mu}m. An image resolution of features less than 0.05--0.1 {mu}m, is obtained over a large area field; i.e., 25.4 mm {times} 25.4 mm, with a distortion less than 0.1 of the resolution over the image field.

  3. Broadband laser diode emitting at 1. 28. mu. m wavelength

    SciTech Connect

    Takada, K.; Noda, J.

    1985-10-15

    This letter presents a broadband laser diode (LD) emitting at the 1.28 ..mu..m wavelength fabricated by introducing an absorption region (300 ..mu..m long) into a conventional 600-..mu..m-long InGaAsP laser diode. The LD operates by the pulsed modulation of a high peak current whose repetition rate and duty cycle are respectively 200 kHz and 5%. The typical output power and the spectral width of the LD are 3.8 mW and 58 A, and the measured coherence length is 210 ..mu..m.

  4. Experiments on ocular tissue ablation at 5.3 and 6.0 {mu}m with the Los Alamos advanced FEL

    SciTech Connect

    Nguyen, D.C.; Ren, Q.; Hill, R.

    1995-12-31

    We investigated the ablation characteristics of a picosecond free-electron laser and compared its ablation effects on ocular tissues at 5.3 {mu}m and 6.0 {mu}m. The Advanced FEL at Los Alamos, operating in the wavelength range 4-6 {mu}m, was used for this study. The 10-{mu}s macropulse consisted of {approximately}1000 micropulses, each approximately 15 ps in length and separated from one another by 9.2 ns. The FEL beam was passed through a series of attenuator and focused to a 200-{mu}m spot in the sample with a 150-mm f.l. CaF{sub 2} lens. The energy in each macropulse ranged from 5 to 120 mJ. Five transplantable corneal-scleral buttons preserved in corneal storage media were used for this study. The tissue sample was positioned at the focused FEL beam for the ablation, and then fixed for histologic study. Corneal cuts made at 6.0 {mu}m revealed a well-defined ablation boundary. The measured lateral zone of the tissue damage was 11 {+-} 2 {mu}m. The integrity of the adjacent tissue was well maintained. By contrast, the ablation boundary of the corneal cuts made at 5.3 {mu}m appeared to be very disruptive. The collagen fiber near the ablation was thermally denatured and lost its organized structure. The lateral dimension of such effect extended out to 220 {mu}m beyond the intended cut into the surrounding tissues. We concluded that a short-pulsed laser operating at 6 {mu}m may be a potentially effective tool for cutting ocular tissues.

  5. Reflective Praxis through Narrative and Poetry: Performing "Peace Mum"

    ERIC Educational Resources Information Center

    Prendergast, Monica

    2010-01-01

    In the autumn of 2007 and spring of 2008 the author performed an adapted version of Dario Fo and Franca Rame's one-woman play "Peace Mom" (retitled for Canadian audiences as "Peace Mum") about American mother and peace activist Cindy Sheehan. The play was performed for University of Victoria Applied Theatre students and also in a number of…

  6. 21 CFR 516.24 - Granting MUMS-drug designation.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Granting MUMS-drug designation. 516.24 Section 516.24 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS NEW ANIMAL DRUGS FOR MINOR USE AND MINOR SPECIES Designation...

  7. 21 CFR 516.24 - Granting MUMS-drug designation.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Granting MUMS-drug designation. 516.24 Section 516.24 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS NEW ANIMAL DRUGS FOR MINOR USE AND MINOR SPECIES Designation...

  8. 21 CFR 516.24 - Granting MUMS-drug designation.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Granting MUMS-drug designation. 516.24 Section 516.24 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS NEW ANIMAL DRUGS FOR MINOR USE AND MINOR SPECIES Designation...

  9. 21 CFR 516.24 - Granting MUMS-drug designation.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Granting MUMS-drug designation. 516.24 Section 516.24 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS NEW ANIMAL DRUGS FOR MINOR USE AND MINOR SPECIES Designation...

  10. THE 5.25 AND 5.7 {mu}m ASTRONOMICAL POLYCYCLIC AROMATIC HYDROCARBON EMISSION FEATURES

    SciTech Connect

    Boersma, C.; Tielens, A. G. G. M.; Mattioda, A. L.; Allamandola, L. J.; Bauschlicher, C. W.; Peeters, E.

    2009-01-10

    Astronomical mid-IR spectra show two minor polycyclic aromatic hydrocarbon (PAH) features at 5.25 and 5.7 {mu}m (1905 and 1754 cm{sup -1}) that hitherto have been little studied, but contain information about the astronomical PAH population that complements that of the major emission bands. Here, we report a study involving both laboratory and theoretical analysis of the fundamentals of PAH spectroscopy that produce features in this region and use these to analyze the astronomical spectra. The Infrared Space Observatory Short Wavelength Spectrograph spectra of 15 objects showing these PAH features were considered for this study, however only four (HD 44179; NGC 7027; Orion Bar, two positions) have sufficient signal-to-noise between 5 and 6 {mu}m to allow for an in-depth analysis. All four astronomical spectra show similar peak positions and profiles. The 5.25 {mu}m feature is peaked and asymmetric, with an FWHM of about 0.12 {+-} 0.01 {mu}m ({approx}40 {+-} 6.5 cm{sup -1}), while the 5.7 {mu}m feature is broader and flatter, with an FWHM of about 0.17 {+-} 0.02 {mu}m (50 {+-} 5.6 cm{sup -1}). Detailed analysis of the laboratory spectra and quantum-chemical calculations show that the astronomical 5.25 and 5.7 {mu}m bands are a blend of combination, difference and overtone bands primarily involving CH stretching and CH in-plane and CH out-of-plane bending fundamental vibrations. The experimental and computational spectra show that, of all the hydrogen adjacency classes that are possible on PAHs, solo and duo hydrogens consistently produce prominent bands at the observed positions, whereas quartet hydrogens do not. In all, this study supports the picture that astronomical PAHs are large with compact, regular structures. From the coupling with primarily strong CH out-of-plane bending modes, one might surmise that the 5.25 and 5.7 {mu}m bands track the neutral PAH population. However, theory suggests that the role of charge in these astronomical bands might also be

  11. Dementia in documentary film: mum by Adelheid Roosen.

    PubMed

    Swinnen, Aagje

    2013-02-01

    This article draws attention to the fact that documentaries do not simply reproduce the reality that film and audience share but always present a particular view of this reality. This implies that organizations in Alzheimer care, education, and research that often recommend documentaries to inform people about dementia should take into account that these films might reinforce negative stereotypes inducing fear of dementia. An in-depth analysis of the Dutch short documentary Mum (2009), directed by feminist artist Adelheid Roosen, illustrates that the reasoning of the personhood movement in dementia research can be translated into an artistic form. By highlighting instead of veiling its means of production, Mum stimulates viewers to imagine people with dementia as other than lost selves. PMID:22539659

  12. Dementia in documentary film: mum by Adelheid Roosen.

    PubMed

    Swinnen, Aagje

    2013-02-01

    This article draws attention to the fact that documentaries do not simply reproduce the reality that film and audience share but always present a particular view of this reality. This implies that organizations in Alzheimer care, education, and research that often recommend documentaries to inform people about dementia should take into account that these films might reinforce negative stereotypes inducing fear of dementia. An in-depth analysis of the Dutch short documentary Mum (2009), directed by feminist artist Adelheid Roosen, illustrates that the reasoning of the personhood movement in dementia research can be translated into an artistic form. By highlighting instead of veiling its means of production, Mum stimulates viewers to imagine people with dementia as other than lost selves.

  13. 350 {mu}m POLARIMETRY FROM THE CALTECH SUBMILLIMETER OBSERVATORY

    SciTech Connect

    Dotson, Jessie L.; Vaillancourt, John E.; Kirby, Larry; Hildebrand, Roger H.; Dowell, C. Darren; Davidson, Jacqueline A. E-mail: jvaillancourt@sofia.usra.edu

    2010-02-01

    We present a summary of data obtained with the 350 {mu}m polarimeter, Hertz, at the Caltech Submillimeter Observatory. We give tabulated results and maps showing polarization vectors and intensity contours. The summary includes over 4300 individual measurements in 56 Galactic sources and two galaxies. Of these measurements, 2153 have P {>=} 3{sigma} {sub p} statistical significance. The median polarization of the entire data set is 1.46%.

  14. SPATIALLY RESOLVING THE HK Tau B EDGE-ON DISK FROM 1.2 TO 4.7 {mu}m: A UNIQUE SCATTERED LIGHT DISK

    SciTech Connect

    McCabe, C.; Duchene, G.; Pinte, C.; Menard, F.; Ghez, A. M. E-mail: Gaspard.Duchene@obs.ujf-grenoble.fr E-mail: Francois.Menard@obs.ujf-grenoble.fr

    2011-02-01

    We present spatially resolved scattered light images of the circumstellar disk around HK Tau B at 3.8 and 4.7 {mu}m taken with the Keck Telescope Laser Guide Star Adaptive Optics (AO) system, and 1.6-2.12 {mu}m images taken with the Very Large Telescope/NACO AO system. Combined with previously published optical Hubble Space Telescope data, we investigate the spatially resolved scattered light properties of this edge-on circumstellar disk and probe for the presence of large grains. The 0.6-3.8 {mu}m scattered light observations reveal strong, and in some cases, unusual, wavelength dependencies in the observed disk morphology. The separation between the two scattered light nebulae, which is directly proportional to the disk-mass-opacity product, decreases by 30% between 0.6 and 3.8 {mu}m. Over the same wavelength range, the FWHM of the disk nebulosity declines by a factor of two, while the flux ratio between the two nebulae increases by a factor of {approx}8. No other disk known to date shows a flux ratio that increases with wavelength. Both the FWHM and nebula flux ratio are affected by the scattering phase function and the observed behavior can most readily be explained by a phase function that becomes more forward throwing with wavelength. The multi-wavelength scattered light observations also confirm the asymmetric nature of the disk and show that the level of asymmetry is a function of wavelength. We use the MCFOST radiative transfer code to model the disk at four wavelengths, corresponding to the I, H, Ks, and L' bandpasses. A single power-law grain size distribution can recreate the observed disk properties simultaneously at all four wavelengths. Bayesian analysis of the dust parameters finds a 99% probability that the maximum grain size is 5.5 {mu}m or larger. We also find that the grain size distribution is steep, with a 99% probability of a power-law index of 4.2 or larger, suggesting that these large grains are a small fraction of the overall dust

  15. USING THE 1.6 {mu}m BUMP TO STUDY REST-FRAME NEAR-INFRARED-SELECTED GALAXIES AT REDSHIFT 2

    SciTech Connect

    Sorba, Robert; Sawicki, Marcin

    2010-10-01

    We explore the feasibility and limitations of using the 1.6 {mu}m bump as a photometric redshift indicator and selection technique, and use it to study the rest-frame H-band galaxy luminosity and stellar mass functions (SMFs) at redshift z {approx} 2. We use publicly available Spitzer/IRAC images in the GOODS fields and find that color selection in the IRAC bandpasses alone is comparable in completeness and contamination to BzK selection. We find that the shape of the 1.6 {mu}m bump is robust, and photometric redshifts are not greatly affected by choice of model parameters. Comparison with spectroscopic redshifts shows photometric redshifts to be reliable. We create a rest-frame NIR-selected catalog of galaxies at z {approx} 2 and construct a galaxy SMF. Comparisons with other SMFs at approximately the same redshift but determined using shorter wavelengths show good agreement. This agreement suggests that selection at bluer wavelengths does not miss a significant amount of stellar mass in passive galaxies. Comparison with SMFs at other redshifts shows evidence for the downsizing scenario of galaxy evolution. We conclude by pointing out the potential for using the 1.6 {mu}m bump technique to select high-redshift galaxies with the JWST, whose {lambda}>0.6 {mu}m coverage will not be well suited to selecting galaxies using techniques that require imaging at shorter wavelengths.

  16. OPTICAL CONSTANTS OF AMORPHOUS AND CRYSTALLINE H{sub 2}O-ICE: 2.5-22 {mu}m (4000-455 cm{sup -1}) OPTICAL CONSTANTS OF H{sub 2}O-ICE

    SciTech Connect

    Mastrapa, R. M.; Dalle Ore, C. M.; Sandford, S. A.; Cruikshank, D. P.; Roush, T. L.

    2009-08-20

    Using new laboratory spectra, we have calculated the real and imaginary parts of the index of refraction of amorphous and crystalline H{sub 2}O-ice from 20-150 K in the wavelength range 2.5-22 {mu}m (4000-455 cm{sup -1}) and joined these results with previous measurement from 1.25 to 2.5 {mu}m. These optical constants improve on previous measurements by having better temperature and spectral resolution and can be used to create model spectra for comparison to spectra of solar system objects and interstellar materials. In this wavelength range, the infrared band shapes and positions of amorphous H{sub 2}O-ice are strongly dependent on deposition temperature. Amorphous and crystalline H{sub 2}O-ice have distinctive spectral bands at all wavelengths in this region with bands weakening and shifting to shorter wavelength in amorphous H{sub 2}O-ice compared to crystalline H{sub 2}O-ice. Some notable exceptions are the band near 6 {mu}m, which is stronger in amorphous H{sub 2}O-ice, and the bands near 4.5 {mu}m and 12.5 {mu}m, which shift to longer wavelength in amorphous H{sub 2}O-ice.

  17. 2-.mu.m fiber amplified spontaneous emission (ASE) source

    NASA Technical Reports Server (NTRS)

    Jiang, Shibin (Inventor); Wu, Jianfeng (Inventor); Geng, Jihong (Inventor)

    2007-01-01

    A 2-.mu.m fiber Amplified Spontaneous Emission (ASE) source provides a wide emission bandwidth and improved spectral stability/purity for a given output power. The fiber ASE source is formed from a heavy metal oxide multicomponent glass selected from germanate, tellurite and bismuth oxides and doped with high concentrations, 0.5-15 wt. %, thulium oxides (Tm.sub.2O.sub.3) or 0.1-5 wt% holmium oxides (Ho.sub.2O.sub.3) or mixtures thereof. The high concentration of thulium dopants provide highly efficient pump absorption and high quantum efficiency. Co-doping of Tm and Ho can broaden the ASE spectrum.

  18. [Dementia in documentary film: Mum by Adelheid Roosen].

    PubMed

    Swinnen, A M C

    2012-10-01

    This article draws attention to the fact that documentaries do not simply reproduce the reality that film and audience share but always present a particular view of this reality. This implies that organizations in Alzheimer care, education, and research that often recommend documentaries to inform people about dementia should take into account that these films might reinforce negative stereotypes inducing fear of dementia. An in-depth analysis of the Dutch short documentary Mum, directed by Adelheid Roosen, illustrates that the body of ideas of the personhood movement in dementia research can be translated into an artistic form. By highlighting instead of veiling its means of production, the documentary stimulates viewers to imagine people with dementia as other than lost selves. The original version of this article in The Gerontologist was made available April 26, 2012. PMID:23167068

  19. [Dementia in documentary film: Mum by Adelheid Roosen].

    PubMed

    Swinnen, A M C

    2012-10-01

    This article draws attention to the fact that documentaries do not simply reproduce the reality that film and audience share but always present a particular view of this reality. This implies that organizations in Alzheimer care, education, and research that often recommend documentaries to inform people about dementia should take into account that these films might reinforce negative stereotypes inducing fear of dementia. An in-depth analysis of the Dutch short documentary Mum, directed by Adelheid Roosen, illustrates that the body of ideas of the personhood movement in dementia research can be translated into an artistic form. By highlighting instead of veiling its means of production, the documentary stimulates viewers to imagine people with dementia as other than lost selves. The original version of this article in The Gerontologist was made available April 26, 2012.

  20. Efficient lasing at 2.1 {mu}m in a Ho:YAG laserpumped by a Tm:YLF laser

    SciTech Connect

    Zakharov, N G; Sharkov, V V; Savikin, A P; Antipov, Oleg L

    2010-02-28

    A laser based on a Ho:YAG crystal operating at a wavelength of {approx}2.1 {mu}m under pumping by Tm:YLF laser radiation with a wavelength of 1.908 {mu}m is studied. The laser operates in cw and repetitively pulsed regimes with a high beam quality (quality factor M{sup 2{<=}}1.2). The cw radiation power reached 15 W with the total optical efficiency of {approx}55 %. In the active Q-switched regime (achieved using an acousto-optic Q-switch), a highly stable repetitively pulsed lasing was obtained with a pulse repetition rate of 2.5-10 kHz, a pulse duration of 25-55 ns, and an average power up to 14.7 W. Using intracavity frequency selection, lasing was obtained at individual spectral lines in three wavelength regions, near 2.09, 2.097, and 2.123 {mu}m. (lasers)

  1. Optical amplification at the 1.31 wavelength

    DOEpatents

    Cockroft, Nigel J.

    1994-01-01

    An optical amplifier operating at the 1.31 .mu.m wavelength for use in such applications as telecommunications, cable television, and computer systems. An optical fiber or other waveguide device is doped with both Tm.sup.3+ and Pr.sup.3+ ions. When pumped by a diode laser operating at a wavelength of 785 nm, energy is transferred from the Tm.sup.3+ ions to the Pr.sup.3+ ions, causing the Pr.sup.3+ ions to amplify at a wavelength of 1.31

  2. 40 CFR 721.6100 - Phosphoric acid, C6-12-alkyl esters, compounds with 2-(dibutylamino) ethanol.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Phosphoric acid, C6-12-alkyl esters... Significant New Uses for Specific Chemical Substances § 721.6100 Phosphoric acid, C6-12-alkyl esters... reporting. (1) The chemical substances identified as phosphoric acid, C6-12-alkyl esters, compounds with...

  3. 40 CFR 721.6100 - Phosphoric acid, C6-12-alkyl esters, compounds with 2-(dibutylamino) ethanol.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Phosphoric acid, C6-12-alkyl esters... Significant New Uses for Specific Chemical Substances § 721.6100 Phosphoric acid, C6-12-alkyl esters... reporting. (1) The chemical substances identified as phosphoric acid, C6-12-alkyl esters, compounds with...

  4. 40 CFR 721.6100 - Phosphoric acid, C6-12-alkyl esters, compounds with 2-(dibutylamino) ethanol.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Phosphoric acid, C6-12-alkyl esters... Significant New Uses for Specific Chemical Substances § 721.6100 Phosphoric acid, C6-12-alkyl esters... reporting. (1) The chemical substances identified as phosphoric acid, C6-12-alkyl esters, compounds with...

  5. 40 CFR 721.6100 - Phosphoric acid, C6-12-alkyl esters, compounds with 2-(dibutylamino) ethanol.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Phosphoric acid, C6-12-alkyl esters... Significant New Uses for Specific Chemical Substances § 721.6100 Phosphoric acid, C6-12-alkyl esters... reporting. (1) The chemical substances identified as phosphoric acid, C6-12-alkyl esters, compounds with...

  6. 40 CFR 721.6100 - Phosphoric acid, C6-12-alkyl esters, compounds with 2-(dibutylamino) ethanol.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Phosphoric acid, C6-12-alkyl esters... Significant New Uses for Specific Chemical Substances § 721.6100 Phosphoric acid, C6-12-alkyl esters... reporting. (1) The chemical substances identified as phosphoric acid, C6-12-alkyl esters, compounds with...

  7. Single-Particle Laser Doppler Anemometry at 1.55 mum.

    PubMed

    Harris, M; Pearson, G N; Ridley, K D; Karlsson, C J; Olsson, F A; Letalick, D

    2001-02-20

    We demonstrate the successful operation of a cw laser Doppler wind sensor at a wavelength of 1.55 mum. At longer ranges (>100 m) the signal conforms closely to complex Gaussian statistics, consistent with the incoherent addition of contributions from a large number of scattering aerosols. As the range is reduced, the probe volume rapidly diminishes and the signal statistics are dramatically modified. At the shortest ranges (<8 m) the signal becomes dominated by short bursts, each originating from a single particle within the measurement volume. These single-particle events can have a very high signal-to-noise ratio (SNR) because (1) the signal becomes concentrated within a small time window and (2) its bandwidth is much reduced compared with multiparticle detection. Examples of wind-signal statistics at different ranges and for a variety of atmospheric backscatter conditions are presented. Results show that single-particle-scattering events play a significant role even to ranges of ~50 m, leading to results inconsistent with complex Gaussian statistics. The potential is assessed for a low-power laser Doppler wind sensor that exploits the SNR enhancement obtained with single-particle detection.

  8. Teens on Target Violence Prevention Curriculum for Grades 6-12.

    ERIC Educational Resources Information Center

    Becker, Marla G.; Calhoun, Deane

    This curriculum is designed to help schools implement programs to prevent violence among students in grades 6-12. It is a six-session, school based curriculum intended for adolescents who are living in communities experiencing high rates of violence. It is facilitated by trained Teens on Target (TNT) members/peer educators, young people who are…

  9. University of Chicago School Mathematics Project 6-12 Curriculum. What Works Clearinghouse Intervention Report

    ERIC Educational Resources Information Center

    What Works Clearinghouse, 2011

    2011-01-01

    The "University of Chicago School Mathematics Project ("UCSMP") 6-12 Curriculum" is a series of yearlong courses--(1) Transition Mathematics; (2) Algebra; (3) Geometry; (4) Advanced Algebra; (5) Functions, Statistics, and Trigonometry; and (6) Precalculus and Discrete Mathematics--emphasizing problem solving, real-world applications, and the use…

  10. Health Problems in the Classroom 6-12: An A-Z Reference Guide for Educators.

    ERIC Educational Resources Information Center

    Huffman, Dolores M.; Fontaine, Karen Lee; Price, Bernadette K.

    This guide provides a resource for middle and high school teachers, teacher aides, administrators, and educators, covering health problems that affect students in grades 6-12. The handbook alphabetically lists the most current health concerns for this age group. Part 1, "Health Issues in the Classroom," includes (1) "Health, Illness, and…

  11. 41 CFR 51-6.12 - Specification changes and similar actions.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...-PROCUREMENT PROCEDURES § 51-6.12 Specification changes and similar actions. (a) Contracting activities shall notify the nonprofit agency or agencies authorized to furnish a commodity on the Procurement List and the... Procurement List, including a change that involves the assignment of a new national stock number or...

  12. Improving the Precollegiate Curriculum on Latin America, Grades 6-12. Final Performance Report.

    ERIC Educational Resources Information Center

    Wirth, John D.

    The Latin America Project, which developed print and nonprint materials for use in grades 6-12, is described. The two-year effort was conducted in five phases: survey of existing materials; the development of curriculum units; review of curriculum by teachers attending summer institutes; field testing and evaluation; and dissemination. Titles of…

  13. Sum-frequency generation from molecular monolayers using 14 {mu}m radiation from the FELIX free-electron laser

    SciTech Connect

    Van der Ham, E.W.M.; Vrehen, Q.H.F.; Eliel, E.R.

    1995-12-31

    Sum-frequency generation (SFG) has developed into a widely applied tool for study of surfaces and interfaces where molecules are present. It combines the surface specificity of a second-order nonlinear optical technique with the power of a spectroscopic method, and it can be used under widely varying experimental conditions ranging from UHV to electrochemical cells. The important characteristic of SFG is that it allows one to study the average spatial orientation of a molecular bond in a monolayer of molecules at an interface. Until recently SFG measurements were confined to the frequency interval Y {mu} > 1700 cm{sup -1} because of a lack of suitable laser sources at wave-lengths {lambda} > 6 {mu}m. So for most molecules only a few vibrational modes and thus intramolecular bonds can be studied. We have developed a universal sum-frequency spectrometer around the FELIX free-electron law that covers the complete molecular fingerprint since we can generate any IR wavelength between 2.75 and 110 f{mu} at the FELIX facility. We have used this setup for a series of exploratory SFG experiments in a frequency range that was hitherto unexplored in the study of molecular monolayers. We have studied thiol monolayers chemisorbed on a variety of noble metals (Au, Ag, Pt) where we focussed on the C-S stretch vibration at {nu} = 702 cm{sup -1} ({lambda} = 14.3 {mu}m). We have found spectroscopic features revealing the presence of both the trane and gauche conformers of the adsorbed molecules. The present measurements open a whole new wavelength range for nonlinear optical studies of interfaces.

  14. A FAR-INFRARED CHARACTERIZATION OF 24 {mu}m SELECTED GALAXIES AT 0 < z < 2.5 USING STACKING AT 70 {mu}m AND 160 {mu}m IN THE COSMOS FIELD

    SciTech Connect

    Lee, Nicholas; Le Floc'h, Emeric; Sanders, D. B.; Frayer, D. T.; Arnouts, Stephane; Ilbert, Olivier; Aussel, Herve; Salvato, Mara; Scoville, N. Z.; Kartaltepe, Jeyhan S.

    2010-07-01

    We present a study of the average properties of luminous infrared galaxies detected directly at 24 {mu}m in the COSMOS field using a median stacking analysis at 70 {mu}m and 160 {mu}m. Over 35,000 sources spanning 0 {<=} z {<=} 3 and 0.06 mJy {<=}S{sub 24} {<=} 3.0 mJy are stacked, divided into bins of both photometric redshift and 24 {mu}m flux. We find no correlation of S{sub 70}/S{sub 24} flux density ratio with S{sub 24}, but find that galaxies with higher S{sub 24} have a lower S{sub 160}/S{sub 24} flux density ratio. These observed ratios suggest that 24 {mu}m selected galaxies have warmer spectral energy distributions (SEDs) at higher mid-IR fluxes, and therefore have a possible higher fraction of active galactic nuclei. Comparisons of the average S{sub 70}/S{sub 24} and S{sub 160}/S{sub 24} colors with various empirical templates and theoretical models show that the galaxies detected at 24 {mu}m are consistent with 'normal' star-forming galaxies and warm mid-IR galaxies such as Mrk 231, but inconsistent with heavily obscured galaxies such as Arp 220. We perform a {chi}{sup 2} analysis to determine best-fit galactic model SEDs and total IR luminosities for each of our bins. We compare our results to previous methods of estimating L{sub IR} and find that previous methods show considerable agreement over the full redshift range, except for the brightest S{sub 24} sources, where they overpredict the bolometric IR luminosity at high redshift, most likely due to their warmer dust SED. We present a table that can be used as a more accurate and robust method for estimating bolometric infrared luminosity from 24 {mu}m flux densities.

  15. Broadband Ho{sup 3+}-doped fibre radiation source emitting at 2 {mu}m

    SciTech Connect

    Kurkov, A S; Sholokhov, E M; Paramonov, V M; Kosolapov, A F

    2008-10-31

    A 2-{mu}m broadband radiation source based on a fibre doped with holmium ions, which is pumped by a 1.12-{mu}m ytterbium fibre laser, is developed. The maximum output power of 8 mW is achieved for the emission spectrum width of 45 nm. (active optical fibres)

  16. 21 CFR 516.31 - Scope of MUMS-drug exclusive marketing rights.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Scope of MUMS-drug exclusive marketing rights. 516... SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS NEW ANIMAL DRUGS FOR MINOR USE AND MINOR SPECIES Designation of a Minor Use or Minor Species New Animal Drug § 516.31 Scope of MUMS-drug...

  17. 21 CFR 516.31 - Scope of MUMS-drug exclusive marketing rights.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Scope of MUMS-drug exclusive marketing rights. 516... SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS NEW ANIMAL DRUGS FOR MINOR USE AND MINOR SPECIES Designation of a Minor Use or Minor Species New Animal Drug § 516.31 Scope of MUMS-drug...

  18. 21 CFR 516.31 - Scope of MUMS-drug exclusive marketing rights.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Scope of MUMS-drug exclusive marketing rights. 516... SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS NEW ANIMAL DRUGS FOR MINOR USE AND MINOR SPECIES Designation of a Minor Use or Minor Species New Animal Drug § 516.31 Scope of MUMS-drug...

  19. Metamorphic approach to single quantum dot emission at 1.55 {mu}m on GaAs substrate

    SciTech Connect

    Semenova, E. S.; Hostein, R.; Patriarche, G.; Mauguin, O.; Largeau, L.; Robert-Philip, I.; Beveratos, A.; Lemaitre, A.

    2008-05-15

    We report on the fabrication and the characterization of InAs quantum dots (QDs) embedded in an indium rich In{sub 0.42}Ga{sub 0.58}As metamorphic matrix grown on a GaAs substrate. Growth conditions were chosen so as to minimize the number of threading dislocations and other defects produced during the plastic relaxation. Sharp and bright lines, originating from the emission of a few isolated single quantum dots, were observed in microphotoluminescence around 1.55 {mu}m at 5 K. They exhibit, in particular, a characteristic exciton/biexciton behavior. These QDs could offer an interesting alternative to other approaches as InAs/InP QDs for the realization of single photon emitters at telecom wavelengths.

  20. Temperature sensitivity of KDP for phase-matched frequency conversion of 1 [mu]m laser light

    SciTech Connect

    Webb, M. )

    1994-08-01

    The magnitudes of the derivatives of the phase-matching angles with respect to temperature [vert bar][partial derivative][theta][sub pm]/[partial derivative]T[vert bar] (milliradians/degree Celsius), for critically phase-matched frequency conversion using KDP (KH[sub 2]PO[sub 4]) have been directly measured for the five most interesting processes to inertial confinement fusion (ICF) laser-system designers: 2[omega] I, 2[omega] II, 3[omega] I, 3[omega] II, and 4[omega] I. These measurements span an approximate temperature range of 25 to 90 C, and were performed at a fundamental (1[omega]) wavelength of [lambda] = 1.064 [mu]m. The results are used to calculate the phase-matching thermal-sensitivity parameter ([vert bar][beta][sub T][vert bar]) (centimeter[sup [minus]1]/milliradian), for each conversion process.

  1. Temperature dependence of the threshold current in quantum-well WGM lasers (2.0-2.5 {mu}m)

    SciTech Connect

    Imenkov, A. N.; Sherstnev, V. V. Kovalev, I. V.; Il'inskaya, N. D.; Serebrennikova, O. Yu.; Teissier, R.; Baranov, A. N.; Yakovlev, Yu. P.

    2013-06-15

    The temperature dependence of the threshold current and emission spectra of disk-shaped quantum-well whispering-gallery mode (WGM) lasers is studied in the temperature range of 80-463 K in which the laser emission wavelength increases from 2 to 2.5 {mu}m. It is shown that lasing is observed up to 190 Degree-Sign C. Radiative recombination is dominant up to a temperature of 300 K, and nonradiative Auger recombination, in which a recombining electron gives energy to another electron, is so at higher temperatures. The spin-orbit split-off valence subband is not involved in recombination processes, which is attributed to mechanical compression of the quantum-well material.

  2. Strained layer (1. 5 [mu]m) InP/InGaAsP lasing opto-electronic switch (LOES)

    SciTech Connect

    Swoger, J.H.; Qiu, C.; Simmons, J.G.; Thompson, D.A. . Centre for Electrophotonic Materials and Devices); Sheperd, F.; Beckett, D.; Cleroux, M. )

    1994-08-01

    The authors present for the first time a Lasing Opto-Electronic Switch (LOES) fabricated in the InP/InGaAsP system. In this device the active region is composed of four 63 [angstrom] compressively strained quantum wells. A lasing threshold of 104 mA, or 6933 A/cm[sup 2], has been observed at a temperature of 298 K, with an external differential quantum efficiency of 14%. The lasing wavelength is centered at 1.52 [mu]m. The current-voltage characteristics manifest pronounced differential negative resistance, characterized by switching and holding voltages of 6.8 V and 1.6 V, respectively, and a switching current density of 33 A/cm[sup 2]. The OFF and ON state resistances are approximately 150 k[Omega] and 4 [Omega], respectively.

  3. 1.59 {mu}m room temperature emission from metamorphic InAs/InGaAs quantum dots grown on GaAs substrates

    SciTech Connect

    Seravalli, L.; Frigeri, P.; Trevisi, G.; Franchi, S.

    2008-05-26

    We present design, preparation by molecular beam epitaxy, and characterization by photoluminescence of long-wavelength emitting, strain-engineered quantum dot nanostructures grown on GaAs, with InGaAs confining layers and additional InAlAs barriers embedding InAs dots. Quantum dot strain induced by metamorphic lower confining layers is instrumental to redshift the emission, while a-few-nanometer thick InAlAs barriers allow to significantly increase the activation energy of carriers' thermal escape. This approach results in room temperature emission at 1.59 {mu}m and, therefore, is a viable method to achieve efficient emission in the 1.55 {mu}m window and beyond from quantum dots grown on GaAs substrates.

  4. 1.55 {mu}m GaAs/GaNAsSb/GaAs optical waveguides grown by radio frequency nitrogen plasma-assisted molecular beam epitaxy

    SciTech Connect

    Tan, K. H.; Yoon, S. F.; Loke, W. K.; Wicaksono, S.; Xu, Z.; Ng, T. K.; Lew, K. L.; Saadsaoud, N.; Zegaoui, M.; Decoster, D.; Chazelas, J.

    2008-03-17

    We demonstrate a 1.55 {mu}m GaAs/GaNAsSb/GaAs optical waveguide grown by molecular beam epitaxy as an alternative to the AlGaAs/GaAs system. The 0.4-{mu}m-thick GaNAsSb guiding layer contains {approx}3.5% of N and 9% of Sb, resulting in optical band gap of 0.88 eV. The refractive index of the GaNAsSb layer was measured from 800 to 1700 nm. The GaNAsSb layer has a refractive index value of 3.42 at 1.55 {mu}m wavelength. The propagation loss measured using the Fabry-Perot resonance method was found to be affected by nitrogen-related defect absorption.

  5. Dual Wavelength Lasers

    NASA Technical Reports Server (NTRS)

    Walsh, Brian M.

    2010-01-01

    Dual wavelength lasers are discussed, covering fundamental aspects on the spectroscopy and laser dynamics of these systems. Results on Tm:Ho:Er:YAG dual wavelength laser action (Ho at 2.1 m and Er at 2.9 m) as well as Nd:YAG (1.06 and 1.3 m) are presented as examples of such dual wavelength systems. Dual wavelength lasers are not common, but there are criteria that govern their behavior. Based on experimental studies demonstrating simultaneous dual wavelength lasing, some general conclusions regarding the successful operation of multi-wavelength lasers can be made.

  6. FIRST SCIENCE RESULTS FROM SOFIA/FORCAST: SUPER-RESOLUTION IMAGING OF THE S140 CLUSTER AT 37 {mu}m

    SciTech Connect

    Harvey, Paul M.; Adams, Joseph D.; Herter, Terry L.; Gull, George; Schoenwald, Justin E-mail: jdadams@astro.cornell.edu E-mail: geg3@cornell.edu; and others

    2012-04-20

    We present 37 {mu}m imaging of the S140 complex of infrared sources centered on IRS1 made with the FORCAST camera on SOFIA. These observations are the longest wavelength imaging to resolve clearly the three main sources seen at shorter wavelengths, IRS 1, 2, and 3, and are nearly at the diffraction limit of the 2.5 m telescope. We also obtained a small number of images at 11 and 31 {mu}m that are useful for flux measurement. Our images cover the area of several strong submillimeter sources seen in the area-SMM 1, 2, and 3-that are not coincident with any mid-infrared sources and are not visible in our longer wavelength imaging either. Our new observations confirm previous estimates of the relative dust optical depth and source luminosity for the components in this likely cluster of early B stars. We also investigate the use of super-resolution to go beyond the basic diffraction limit in imaging on SOFIA and find that the van Cittert algorithm, together with the 'multi-resolution' technique, provides excellent results.

  7. DISCOVERY AND ANALYSIS OF 21 {mu}m FEATURE SOURCES IN THE MAGELLANIC CLOUDS

    SciTech Connect

    Volk, Kevin; Meixner, Margaret; Gordon, Karl D.; Hrivnak, Bruce J.; Matsuura, Mikako; Bernard-Salas, Jeronimo; Sloan, G. C.; Kraemer, Kathleen E.; Kemper, F.; Woods, Paul M.; Zijlstra, Albert A.; Sahai, Raghvendra; Gruendl, Robert A.; Tielens, Alexander G. G. M.; Indebetouw, Remy; Marengo, Massimo

    2011-07-10

    Spitzer Space Telescope mid-infrared spectroscopy has been obtained for 15 carbon-rich protoplanetary nebulae (PPNe) in the Large Magellanic Cloud (LMC) and for two other such stars in the Small Magellanic Cloud (SMC). Of these 17 PPNe, the unidentified 21 {mu}m feature is strong in 7 spectra, weak in 2 spectra, and very weak or questionable in 4 spectra. Two of the four spectra without the 21 {mu}m feature have a very strong feature near 11 {mu}m, similar to a feature observed in some carbon-rich planetary nebulae (PNe) in the LMC. We attribute this feature to unusual SiC dust, although the feature-to-continuum ratio is much larger than for SiC features in Galactic or Magellanic Cloud carbon star spectra. The remaining two objects show typical carbon-rich PPNe spectra with no 21 {mu}m features. One of the LMC objects that lacks the 21 {mu}m feature and one SMC object with a questionable 21 {mu}m detection may have mixed dust chemistries based upon their spectral similarity to Galactic [WC] PNe. The 13 objects that either definitely or may show the 21 {mu}m feature have distinct dust shell properties compared to the Galactic 21 {mu}m objects-the 21 {mu}m features are weaker, the estimated dust temperatures are significantly higher, the unidentified infrared (UIR) bands are stronger, and the UIRs show more structure. Four of the 21 {mu}m objects appear to show normal SiC emission features in their spectra. Many of the PPNe show strong 30 {mu}m features, although this feature carries less of the total mid-infrared emission than is normally the case for the Galactic 21 {mu}m PPNe. The LMC objects are in the LMC halo rather than in the LMC bar. The estimated luminosities of these PPNe vary from 4700 to 12,500 L{sub sun}.

  8. Vibrational and thermodynamic properties of α-, β-, γ-, and 6, 6, 12-graphyne structures.

    PubMed

    Perkgöz, Nihan Kosku; Sevik, Cem

    2014-05-01

    Electronic, vibrational, and thermodynamic properties of different graphyne structures, namely α-, β-, γ-, and 6, 6, 12-graphyne, are investigated through first principles-based quasi-harmonic approximation by using phonon dispersions predicted from density-functional perturbation theory. Similar to graphene, graphyne was shown to exhibit a structure with extraordinary electronic features, mechanical hardness, thermal resistance, and very high conductivity from different calculation methods. Hence, characterizing its phonon dispersions and vibrational and thermodynamic properties in a systematic way is of great importance for both understanding its fundamental molecular properties and also figuring out its phase stability issues at different temperatures. Thus, in this research work, thermodynamic stability of different graphyne allotropes is assessed by investigating vibrational properties, lattice thermal expansion coefficients, and Gibbs free energy. According to our results, although the imaginary vibrational frequencies exist for β-graphyne, there is no such a negative behavior for α-, γ-, and 6, 6, 12-graphyne structures. In general, the Grüneisen parameters and linear thermal expansion coefficients of these structures are calculated to be rather more negative when compared to those of the graphene structure. In addition, the predicted difference between the binding energies per atom for the structures of graphene and graphyne points out that graphyne networks have relatively lower phase stability in comparison with the graphene structures. PMID:24737253

  9. Electronic properties and carrier mobilities of 6,6,12-graphyne nanoribbons

    SciTech Connect

    Ding, Heyu; Huang, Yuanhe; Bai, Hongcun

    2015-07-15

    Structures, stabilities, electronic properties and carrier mobilities of 6,6,12-graphyne nanoribbons (GyNRs) with armchair and zigzag edges are investigated using the self-consistent field crystal orbital method based on density functional theory. It is found that the 1D GyNRs are more stable than the 2D 6,6,12-graphyne sheet in the view of the Gibbs free energy. The stabilities of these GyNRs decrease as their widths increase. The calculated band structures show that all these GyNRs are semiconductors and that dependence of band gaps on the ribbon width is different from different types of the GyNRs. The carrier mobility was calculated based on the deformation theory and effective mass approach. It is found that the carrier mobilities of these GyNRs can reach the order of 10{sup 5} cm{sup 2} V {sup –1}s{sup –1} at room temperature and are comparable to those of graphene NRs. Moreover, change of the mobilities with change of the ribbon width is quite different from different types of the GyNRs.

  10. High-quality GaNAs/GaAs quantum wells with light emission up to 1.44 {mu}m grown by molecular-beam epitaxy

    SciTech Connect

    Wang, S.M.; Gu, Q.F.; Wei, Y.Q.; Sadeghi, M.; Larsson, A.; Zhao, Q.X.; Wang, X.D.; Ma, C.H.; Xing, Z.G.

    2005-10-03

    High-quality GaNAs/GaAs quantum wells with high substitutional N concentrations, grown by molecular-beam epitaxy, are demonstrated using a reduced growth rate in a range of 0.125-1 {mu}m/h. No phase separation is observed and the GaNAs well thickness is limited by the critical thickness. Strong room-temperature photoluminescence with a record long wavelength of 1.44 {mu}m is obtained from an 18-nm-thick GaN{sub 0.06}As{sub 0.94}/GaAs quantum well.

  11. 2 {mu}m laterally coupled distributed-feedback GaSb-based metamorphic laser grown on a GaAs substrate

    SciTech Connect

    Apiratikul, P.; He, L.; Richardson, C. J. K.

    2013-06-10

    We report a type-I GaSb-based laterally coupled distributed-feedback (DFB) laser grown on a GaAs substrate operating continuous wave at room temperature. The laser structure was designed to operate near a wavelength of 2 {mu}m and was grown metamorphically with solid-source molecular beam epitaxy. The device was fabricated using a 6th-order deep etch grating structure as part of the sidewalls of the narrow ridge waveguide. The DFB laser emits total output power of up to 40 mW in a single longitudinal mode operation at a heat-sink temperature of 20 Degree-Sign C.

  12. Q-switched lasing at 2 {mu}m in a Tm{sup 3+}:YAlO{sub 3} laser

    SciTech Connect

    Ushakov, S N; Khromov, M N; Shestakov, A V

    2009-05-31

    The parameters of a Q-switched longitudinally-diode-pumped Tm{sup 3+}:YAlO{sub 3} laser are presented. The pulse repetition rate is f = 1-15 Hz. The maximum average output power is 5 W (at f = 5-15 kHz), the minimum pulse duration is 130 ns (f = 1 kHz), the efficiency is 26% (with the slope efficiency of 58%). The laser wavelength under pumping in the region of 803-805 nm is 1.99 {mu}m. (lasers and amplifiers)

  13. THE CARNEGIE HUBBLE PROGRAM: THE LEAVITT LAW AT 3.6 {mu}m AND 4.5 {mu}m IN THE LARGE MAGELLANIC CLOUD

    SciTech Connect

    Scowcroft, Victoria; Freedman, Wendy L.; Madore, Barry F.; Monson, Andrew J.; Persson, S. E.; Seibert, Mark; Rigby, Jane R.; Sturch, Laura E-mail: wendy@obs.carnegiescience.edu E-mail: amonson@obs.carnegiescience.edu E-mail: mseibert@obs.carnegiescience.edu E-mail: lsturch@bu.edu

    2011-12-10

    The Carnegie Hubble Program is designed to improve the extragalactic distance scale using data from the post-cryogenic era of Spitzer. The ultimate goal is a determination of the Hubble constant to an accuracy of 2%. This paper is the first in a series on the Cepheid population of the Large Magellanic Cloud, and focusses on the period-luminosity (PL) relations (Leavitt laws) that will be used, in conjunction with observations of Milky Way Cepheids, to set the slope and zero point of the Cepheid distance scale in the mid-infrared. To this end, we have obtained uniformly sampled light curves for 85 LMC Cepheids, having periods between 6 and 140 days. PL and period-color relations are presented in the 3.6 {mu}m and 4.5 {mu}m bands. We demonstrate that the 3.6 {mu}m band is a superb distance indicator. The cyclical variation of the [3.6]-[4.5] color has been measured for the first time. We attribute the amplitude and phase of the color curves to the dissociation and recombination of CO molecules in the Cepheid's atmosphere. The CO affects only the 4.5 {mu}m flux making it a potential metallicity indicator.

  14. 21 CFR 516.31 - Scope of MUMS-drug exclusive marketing rights.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS NEW ANIMAL DRUGS FOR MINOR USE AND MINOR SPECIES Designation of a Minor Use or Minor Species New Animal Drug § 516.31 Scope of MUMS-drug...

  15. 21 CFR 516.31 - Scope of MUMS-drug exclusive marketing rights.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS NEW ANIMAL DRUGS FOR MINOR USE AND MINOR SPECIES Designation of a Minor Use or Minor Species New Animal Drug § 516.31 Scope of MUMS-drug...

  16. Wavelength dependence of characteristics of 1. 2-1. 55. mu. m InGaAsP/InP P-substrate buried crescent laser diodes

    SciTech Connect

    Kakimoto, S.; Takemoto, A.; Sakakibara, Y.; Nakajima, Y.; Fujiwara, M.; Namizaki, H.; Higuchi, H.; Yamamoto, Y.

    1988-01-01

    Various wavelength laser diodes with p-substrate buried crescent (PBC) structure have been fabricated at 1.2-1.55 ..mu..m. The dependences of laser characteristics on wavelength have been measured. Up to 70/sup 0/C, the increasing rates of the threshold current with temperature of these lasers are similar, while, above 70/sup 0/C, a shorter wavelength laser shows a larger increasing rate. At the same full width at half maximum of the far-field pattern perpendicular to the junction plane, the external differential quantum efficiency of 1.55 ..mu..m laser diode is found to be only 10 percent smaller than that of the 1.3 ..mu..m laser. The absorption loss coefficients in the active layer of 1.2, 1.3, and 1.55 ..mu..m laser are estimated to be 26, 34, and 73 cm/sup -1/, respectively.

  17. Investigation of Antioxidative and Anticancer Potentials of Streptomyces sp. MUM256 Isolated from Malaysia Mangrove Soil

    PubMed Central

    Tan, Loh Teng-Hern; Ser, Hooi-Leng; Yin, Wai-Fong; Chan, Kok-Gan; Lee, Learn-Han; Goh, Bey-Hing

    2015-01-01

    A Streptomyces strain, MUM256 was isolated from Tanjung Lumpur mangrove soil in Malaysia. Characterization of the strain showed that it has properties consistent with those of the members of the genus Streptomyces. In order to explore the potential bioactivities, extract of the fermented broth culture of MUM256 was prepared with organic solvent extraction method. DPPH and SOD activity were utilized to examine the antioxidant capacity and the results have revealed the potency of MUM256 in superoxide anion scavenging activity in dose-dependent manner. The cytotoxicity of MUM256 extract was determined using cell viability assay against 8 different panels of human cancer cell lines. Among all the tested cancer cells, HCT116 was the most sensitive toward the extract treatment. At the highest concentration of tested extract, the result showed 2.3-, 2.0-, and 1.8-folds higher inhibitory effect against HCT116, HT29, and Caco-2 respectively when compared to normal cell line. This result has demonstrated that MUM256 extract was selectively cytotoxic toward colon cancer cell lines. In order to determine the constituents responsible for its bioactivities, the extract was then subjected to chemical analysis using GC-MS. The analysis resulted in the identification of chemical constituents including phenolic and pyrrolopyrazine compounds which may responsible for antioxidant and anticancer activities observed. Based on the findings of this study, the presence of bioactive constituents in MUM256 extract could be a potential source for the development of antioxidative and chemopreventive agents. PMID:26635777

  18. Wavelength independent interferometer

    NASA Technical Reports Server (NTRS)

    Hochberg, Eric B. (Inventor); Page, Norman A. (Inventor)

    1991-01-01

    A polychromatic interferometer utilizing a plurality of parabolic reflective surfaces to properly preserve the fidelity of light wavefronts irrespective of their wavelengths as they pass through the instrument is disclosed. A preferred embodiment of the invention utilizes an optical train which comprises three off-axis parabolas arranged in conjunction with a beam-splitter and a reference mirror to form a Twyman-Green interferometer. An illumination subsystem is provided and comprises a pair of lasers at different preselected wavelengths in the visible spectrum. The output light of the two lasers is coaxially combined by means of a plurality of reflectors and a grating beam combiner to form a single light source at the focal point of the first parabolic reflection surface which acts as a beam collimator for the rest of the optical train. By using visible light having two distinct wavelengths, the present invention provides a long equivalent wavelength interferogram which operates at visible light wherein the effective wavelength is equal to the product of the wavelengths of the two laser sources divided by their difference in wavelength. As a result, the invention provides the advantages of what amounts to long wavelength interferometry but without incurring the disadvantage of the negligible reflection coefficient of the human eye to long wavelength frequencies which would otherwise defeat any attempt to form an interferogram at that low frequency using only one light source.

  19. SHELS: OPTICAL SPECTRAL PROPERTIES OF WISE 22 {mu}m SELECTED GALAXIES

    SciTech Connect

    Hwang, Ho Seong; Geller, Margaret J.; Kurtz, Michael J.; Fabricant, Daniel G.; Dell'Antonio, Ian P. E-mail: mgeller@cfa.harvard.edu E-mail: dfabricant@cfa.harvard.edu

    2012-10-10

    We use a dense, complete redshift survey, the Smithsonian Hectospec Lensing Survey (SHELS), covering a 4 deg{sup 2} region of a deep imaging survey, the Deep Lens Survey (DLS), to study the optical spectral properties of Wide-field Infrared Survey Explorer (WISE) 22 {mu}m selected galaxies. Among 507 WISE 22 {mu}m selected sources with (S/N){sub 22{mu}m} {>=} 3 ( Almost-Equal-To S{sub 22{mu}m} {approx}> 2.5 mJy), we identify the optical counterparts of 481 sources ({approx}98%) at R < 25.2 in the very deep, DLS R-band source catalog. Among them, 337 galaxies at R < 21 have SHELS spectroscopic data. Most of these objects are at z < 0.8. The infrared (IR) luminosities are in the range 4.5 Multiplication-Sign 10{sup 8}(L{sub Sun }) {approx}< L{sub IR} {approx}< 5.4 Multiplication-Sign 10{sup 12}(L{sub Sun }). Most 22 {mu}m selected galaxies are dusty star-forming galaxies with a small (<1.5) 4000 A break. The stacked spectra of the 22 {mu}m selected galaxies binned in IR luminosity show that the strength of the [O III] line relative to H{beta} grows with increasing IR luminosity. The optical spectra of the 22 {mu}m selected galaxies also show that there are some ({approx}2.8%) unusual galaxies with very strong [Ne III] {lambda}3869, 3968 emission lines that require hard ionizing radiation such as active galactic nuclei (AGNs) or extremely young massive stars. The specific star formation rates (sSFRs) derived from the 3.6 and 22 {mu}m flux densities are enhanced if the 22 {mu}m selected galaxies have close late-type neighbors. The sSFR distribution of the 22 {mu}m selected galaxies containing AGNs is similar to the distribution for star-forming galaxies without AGNs. We identify 48 dust-obscured galaxy candidates with large ({approx}> 1000) mid-IR to optical flux density ratio. The combination of deep photometric and spectroscopic data with WISE data suggests that WISE can probe the universe to z {approx} 2.

  20. Meaningful, Authentic and Place-Based Informal Science Education for 6-12 Students

    NASA Astrophysics Data System (ADS)

    Ito, E.; Dalbotten, D. M.

    2014-12-01

    American Indians are underrepresented in STEM and especially in Earth sciences. They have the lowest high school graduation rate and highest unemployment. On the other hand, tribes are in search of qualified young people to work in geo- and hydro-technical fields to manage reservations' natural resources. Dalbotten and her collaborators at the Fond du Lac Band of Lake Superior Chippewa and local 6-12 teachers ran a place-based but non-themed informal monthly science camps (gidakiimanaaniwigamig) for 7 years starting 2003. Camps were held on reservation and some activities focused on observing seasonal changes. The students enjoyed coming to the camps but the camp activities went largely unnoticed by the reservation itself. For the last 5 years, we and the same cast of characters from the gidakiimanaaniwigamig camps ran a very place-based, research-based camp program, manoomin. The research was focused on manoomin (wild rice) which is a culturally important plant and food that grows in local lakes and wetlands. Manmade changes in hydrology, toxic metals from mining, and changing weather patterns due to climate change threaten this precious resource. Our plan was for 6-12 students to investigate the past, the present and the future conditions of manoomin on and around the reservation. It became clear by 3rd year that the research project, as conceived, was overly ambitious and could not be completed at the level we hoped in a camp setting (6 weekend camps = 6 full days per year). However, students felt that they were involved in research that was beneficial to their reservation, reported gaining self-confidence to pursue a career in science, and stated a desired to obtain a college degree. They also became aware of STEM employment opportunities on reservation that they could aim for. The camps also fostered a trusting relationship between researchers at Fond du Lac resource managers and the U. of MN. Based on these experiences, we proposed a new format for these

  1. An Experimental Trial of Adaptive Programming in Drug Court: Outcomes at 6, 12 and 18 Months

    PubMed Central

    Marlowe, Douglas B.; Festinger, David S.; Dugosh, Karen L.; Benasutti, Kathleen M.; Fox, Gloria; Harron, Ashley

    2013-01-01

    Objectives Test whether an adaptive program improves outcomes in drug court by adjusting the schedule of court hearings and clinical case-management sessions pursuant to a priori performance criteria. Methods Consenting participants in a misdemeanor drug court were randomly assigned to the adaptive program (n = 62) or to a baseline-matching condition (n = 63) in which they attended court hearings based on the results of a criminal risk assessment. Outcome measures were re-arrest rates at 18 months post-entry to the drug court and urine drug test results and structured interview results at 6 and 12 months post-entry. Results Although previously published analyses revealed significantly fewer positive drug tests for participants in the adaptive condition during the first 18 weeks of drug court, current analyses indicate the effects converged during the ensuing year. Between-group differences in new arrest rates, urine drug test results and self-reported psychosocial problems were small and non-statistically significant at 6, 12 and 18 months post-entry. A non-significant trend (p = .10) suggests there may have been a small residual impact (Cramer's ν = .15) on new misdemeanor arrests after 18 months. Conclusions Adaptive programming shows promise for enhancing short-term outcomes in drug courts; however, additional efforts are needed to extend the effects beyond the first 4 to 6 months of enrollment. PMID:25346652

  2. MUM-1 expression differentiates AITL with HRS-like cells from cHL

    PubMed Central

    Huang, Wenyong; Xie, Jianlan; Xu, Xiao; Gao, Xue; Xie, Ping; Zhou, Xiaoge

    2015-01-01

    MUM1 is a member of the interferon regulatory factor family of transcription factors. It is normally expressed in plasma cells, late B cells, and activated T cells, and has been described in several B-cell malignancies and some T-cell neoplasms. The aim of our study was to evaluate the role of MUM-1/IRF4 protein in differentiating angioimmunoblastic T cell lymphoma (AITL) with Hodgkin/Reed-Sternberg (HRS)-like cells from cHL. We identified 12 cases of AITL with HRS-like cells and 24 cases of cHL from March 2013 to November 2014. IHC for MUM-1/IRF4 protein was performed on the tissue of these cases and some relevant positive and negative controls. MUM-1 was expressed in HRS-like cells and some neoplastic T-cells in AITL with HRS-like cells (12/12, 100%) and formed the rosettes around the HRS-like cells (12/12, 100%), expressed in HRS cells in classic Hodgkin Lymphoma (cHL) (24/24, 100%) and just one case formed rosettes around the HRS cells (1/24, 4.2%). Based on the results, MUM-1 could be a useful marker for the differential diagnosis between AITL with HRS-like cells and cHL. PMID:26617862

  3. Assessing Students' Understanding of Macroevolution: Concerns regarding the validity of the MUM

    NASA Astrophysics Data System (ADS)

    Novick, Laura R.; Catley, Kefyn M.

    2012-11-01

    In a recent article, Nadelson and Southerland (2010. Development and preliminary evaluation of the Measure of Understanding of Macroevolution: Introducing the MUM. The Journal of Experimental Education, 78, 151-190) reported on their development of a multiple-choice concept inventory intended to assess college students' understanding of macroevolutionary concepts, the Measure of Understanding Macroevolution (MUM). Given that the only existing evolution inventories assess understanding of natural selection, a microevolutionary concept, a valid assessment of students' understanding of macroevolution would be a welcome and necessary addition to the field of science education. Although the conceptual framework underlying Nadelson and Southerland's test is promising, we believe the test has serious shortcomings with respect to validity evidence for the construct being tested. We argue and provide evidence that these problems are serious enough that the MUM should not be used in its current form to measure students' understanding of macroevolution.

  4. Whole-grain food consumption in Singaporean children aged 6-12 years.

    PubMed

    Neo, Jia En; Binte Mohamed Salleh, Saihah; Toh, Yun Xuan; How, Kesslyn Yan Ling; Tee, Mervin; Mann, Kay; Hopkins, Sinead; Thielecke, Frank; Seal, Chris J; Brownlee, Iain A

    2016-01-01

    Public health bodies in many countries are attempting to increase population-wide habitual consumption of whole grains. Limited data on dietary habits exist in Singaporean children. The present study therefore aimed to assess whole grain consumption patterns in Singaporean children and compare these with dietary intake, physical activity and health parameters. Dietary intake (assessed by duplicate, multipass, 24-h food recalls), physical activity (by questionnaire) and anthropometric measurements were collected from a cross-section of 561 Singaporean children aged 6-12 years. Intake of whole grains was evaluated using estimates of portion size and international food composition data. Only 38·3 % of participants reported consuming whole grains during the dietary data collection days. Median intake of whole grains in consumers was 15·3 (interquartile range 5·4-34·8) g/d. The most commonly consumed whole-grain food groups were rice (29·5 %), wholemeal bread (28·9 %) and ready-to-eat breakfast cereals (18·8 %). A significantly lower proportion of Malay children (seven out of fifty-eight; P < 0·0001) consumed whole grains than children of other ethnicities. Only 6 % of all children consumed the amount of whole grains most commonly associated with improved health outcomes (48 g/d). There was no relationship between whole grain consumption patterns and BMI, waist circumference or physical activity but higher whole grain intake was associated with increased fruit, vegetable and dairy product consumption (P < 0·001). These findings demonstrate that consumption of whole grain foods is low at a population level and infrequent in Singaporean children. Future drives to increase whole-grain food consumption in this population are likely to require input from multiple stakeholders. PMID:27547396

  5. Millimeter wavelength propagation studies

    NASA Technical Reports Server (NTRS)

    Hodge, D. B.

    1974-01-01

    The investigations conducted for the Millimeter Wavelength Propagation Studies during the period December, 1966, to June 1974 are reported. These efforts included the preparation for the ATS-5 Millimeter Wavelength Propagation Experiment and the subsequent data acquisition and data analysis. The emphasis of the OSU participation in this experiment was placed on the determination of reliability improvement resulting from the use of space diversity on a millimeter wavelength earth-space communication link. Related measurements included the determination of the correlation between radiometric temperature and attenuation along the earth-space propagation path. Along with this experimental effort a theoretical model was developed for the prediction of attenuation statistics on single and spatially separated earth space propagation paths. A High Resolution Radar/Radiometer System and Low Resolution Radar System were developed and implemented for the study of intense rain cells in preparation for the ATS-6 Millimeter Wavelength Propagation Experiment.

  6. Long wavelength, high gain InAsSb strained-layer superlattice photoconductive detectors

    DOEpatents

    Biefeld, Robert M.; Dawson, L. Ralph; Fritz, Ian J.; Kurtz, Steven R.; Zipperian, Thomas E.

    1991-01-01

    A high gain photoconductive device for 8 to 12 .mu.m wavelength radiation including an active semiconductor region extending from a substrate to an exposed face, the region comprising a strained-layer superlattice of alternating layers of two different InAs.sub.1-x Sb.sub.x compounds having x>0.75. A pair of spaced electrodes are provided on the exposed face, and changes in 8 to 12 .mu.m radiation on the exposed face cause a large photoconductive gain between the spaced electrodes.

  7. Narrow-stripe metal-clad ridge-waveguide laser for 1. 3. mu. m wavelength

    SciTech Connect

    Amann, M.; Stegmueller, B.

    1986-04-21

    Metal-clad ridge-waveguide lasers with stripe widths between 1.5 and 3 ..mu..m have been developed in InGaAsP-InP for 1.3 ..mu..m wavelength. By an appropriate design for these lasers, threshold currents as low as 20 mA are achieved for 200-..mu..m-long cavities. The corresponding low heat dissipation enables cw operation of upside-down mounted devices up to 85 /sup 0/C heat sink temperature.

  8. Characteristics of the 2.65 {mu}m atomic xenon laser

    SciTech Connect

    Hebner, G.A.

    1995-10-01

    The laser characteristics of the 2.65 {mu}m xenon laser transition are reviewed. Measured and extrapolated laser efficiency in nuclear pumped and electron beam pumped system is reported. Previous research has indicated that the reported power efficiency is between 0.1 and 2 percent.

  9. 21 CFR 516.30 - Annual reports for a MUMS-designated drug.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS NEW ANIMAL DRUGS FOR MINOR USE AND MINOR SPECIES Designation of a Minor Use or Minor Species New Animal Drug § 516.30 Annual reports for a MUMS-designated drug... investigational new animal drug file addressed to the Director of the Office of Minor Use and Minor Species...

  10. 21 CFR 516.30 - Annual reports for a MUMS-designated drug.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS NEW ANIMAL DRUGS FOR MINOR USE AND MINOR SPECIES Designation of a Minor Use or Minor Species New Animal Drug § 516.30 Annual reports for a MUMS-designated drug... investigational new animal drug file addressed to the Director of the Office of Minor Use and Minor Species...

  11. IDENTIFICATION OF THREE NEW PROTOPLANETARY NEBULAE EXHIBITING THE UNIDENTIFIED FEATURE AT 21 {mu}m

    SciTech Connect

    Cerrigone, Luciano; Hora, Joseph L.; Hart, Alexa; Fazio, Giovanni; Umana, Grazia; Trigilio, Corrado E-mail: jhora@cfa.harvard.edu E-mail: gfazio@cfa.harvard.edu E-mail: corrado.trigilio@oact.inaf.it

    2011-09-10

    Among its great findings, the Infrared Astronomical Satellite mission showed the existence of an unidentified mid-IR feature around 21 {mu}m. Since its discovery, this feature has been detected in all C-rich protoplanetary nebulae (PPNe) of intermediate spectral type (F-G) and-weakly-in a few PNe and asymptotic giant branch (AGB) stars, but the nature of its carriers remains unknown. In this paper, we show the detection of this feature in the spectra of three new stars transiting from the AGB to the PN stage obtained with the Spitzer Space Telescope. Following a recent suggestion, we try to model the spectral energy distributions of our targets with amorphous carbon and FeO, which might be responsible for the unidentified feature. The fit thus obtained is not completely satisfactory, since the shape of the feature is not well matched. In an attempt to relate the unidentified feature to other dust features, we retrieved mid-IR spectra of all 21 {mu}m sources currently known from Infrared Space Observatory and Spitzer online archives and noticed a correlation between the flux emitted in the 21 {mu}m feature and that emitted at 7 and 11 {mu}m (polycyclic aromatic hydrocarbon bands and hydrogenated amorphous carbon broad emission). Such a correlation may point to a common nature of the carriers.

  12. Assessing Students' Understanding of Macroevolution: Concerns regarding the Validity of the MUM

    ERIC Educational Resources Information Center

    Novick, Laura R.; Catley, Kefyn M.

    2012-01-01

    In a recent article, Nadelson and Southerland (2010. Development and preliminary evaluation of the Measure of Understanding of Macroevolution: Introducing the MUM. "The Journal of Experimental Education", 78, 151-190) reported on their development of a multiple-choice concept inventory intended to assess college students' understanding of…

  13. "I Asked My Mum, but" and Other Cases of Unsuccessful Information Seeking by Asking

    ERIC Educational Resources Information Center

    Huvila, Isto

    2011-01-01

    Introduction. Failure to find information is common. An exploratory analysis of cases when family members or friends were asked for information can provide better understanding of when, how and why interpersonal information seeking within a close network of individuals fails. Method. A sample of utterances (in form of "I asked my mum, but") was…

  14. High power 2 {mu}m diode-pumped Tm:YAG laser

    SciTech Connect

    Beach, R.J.; Sutton, S.B.; Honea, E.C.; Skidmore, J.A.; Emanuel, M.A.

    1996-01-01

    Using a scaleable diode end-pumping technology developed at LLNL, we have demonstrated a compact Tm:YAG laser capable of generating more than 50 W of cw 2 {mu}m laser output power. The design and operational characteristics of this laser, which was built originally for use in assessing laser surgical techniques, are discussed.

  15. 21 CFR 516.20 - Content and format of a request for MUMS-drug designation.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Content and format of a request for MUMS-drug designation. 516.20 Section 516.20 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... SPECIES Designation of a Minor Use or Minor Species New Animal Drug § 516.20 Content and format of...

  16. 21 CFR 516.30 - Annual reports for a MUMS-designated drug.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS NEW ANIMAL DRUGS FOR MINOR USE AND MINOR SPECIES Designation of a Minor Use or Minor Species New Animal Drug § 516.30 Annual reports for a MUMS-designated drug... investigational new animal drug file addressed to the Director of the Office of Minor Use and Minor Species...

  17. 21 CFR 516.29 - Termination of MUMS-drug designation.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS NEW ANIMAL DRUGS FOR MINOR USE AND MINOR SPECIES Designation of a Minor Use or Minor Species New Animal Drug § 516.29 Termination of MUMS-drug designation. (a... exclusive marketing rights under this subpart. (d) FDA may terminate designation if it...

  18. 21 CFR 516.29 - Termination of MUMS-drug designation.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS NEW ANIMAL DRUGS FOR MINOR USE AND MINOR SPECIES Designation of a Minor Use or Minor Species New Animal Drug § 516.29 Termination of MUMS-drug designation. (a... sponsor; or (5) FDA withdraws the conditional approval or approval of the application for the new...

  19. 21 CFR 516.29 - Termination of MUMS-drug designation.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS NEW ANIMAL DRUGS FOR MINOR USE AND MINOR SPECIES Designation of a Minor Use or Minor Species New Animal Drug § 516.29 Termination of MUMS-drug designation. (a... sponsor; or (5) FDA withdraws the conditional approval or approval of the application for the new...

  20. 21 CFR 516.29 - Termination of MUMS-drug designation.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS NEW ANIMAL DRUGS FOR MINOR USE AND MINOR SPECIES Designation of a Minor Use or Minor Species New Animal Drug § 516.29 Termination of MUMS-drug designation. (a... exclusive marketing rights under this subpart. (d) FDA may terminate designation if it...

  1. Giving Feedback: Development of Scales for the Mum Effect, Discomfort Giving Feedback, and Feedback Medium Preference

    ERIC Educational Resources Information Center

    Cox, Susie S.; Marler, Laura E.; Simmering, Marcia J.; Totten, Jeff W.

    2011-01-01

    Research in organizational behavior and human resources promotes the view that it is critical for managers to provide accurate feedback to employees, yet little research addresses rater tendencies (i.e., the "mum effect") and attitudes that influence how performance feedback is given. Because technology has changed the nature of communication in…

  2. BCL6, MUM1, and CD10 expression in mantle cell lymphoma.

    PubMed

    Gualco, Gabriela; Weiss, Lawrence M; Harrington, William J; Bacchi, Carlos E

    2010-03-01

    Mantle cell lymphoma (MCL) characteristically express CD20, CD5, and cyclin-D1, carries the translocation t(11;14) (q13;q32) and typically has no expression of germinal center cell markers. So-called aberrant phenotypes such as CD5 negative and cyclin-D1-negative MCL have been described. Also few cases with CD10 and/or BCL-6 protein expression have been reported. We analyzed 127 MCL looking for the frequency of aberrant immunophenotype, CD10, BCL-6, and MUM1 expression. All cases were CD20 and cyclin-D1 positive, 96% expressed CD5, and 98% showed the t(11;14). BCL-6 expression was observed in 12% of the cases and MUM1 in 35%. No one case showed CD10 positivity in 30% or more neoplastic cells. Only 3 cases showed 10% to 20% of tumoral cells positive for CD10. MUM1 expression was observed in 67% of the BCL-6 positive cases. Thirty-two percent of the cases showed a MUM1+/BCL-6-/CD10- phenotype and 56% had a triple-negative-pattern. Aberrant phenotype is infrequent but not rare, and does not rule out a diagnosis of MCL in an otherwise typical case.

  3. Iterative development of MobileMums: a physical activity intervention for women with young children

    PubMed Central

    2012-01-01

    Background To describe the iterative development process and final version of ‘MobileMums’: a physical activity intervention for women with young children (<5 years) delivered primarily via mobile telephone (mHealth) short messaging service (SMS). Methods MobileMums development followed the five steps outlined in the mHealth development and evaluation framework: 1) conceptualization (critique of literature and theory); 2) formative research (focus groups, n= 48); 3) pre-testing (qualitative pilot of intervention components, n= 12); 4) pilot testing (pilot RCT, n= 88); and, 5) qualitative evaluation of the refined intervention (n= 6). Results Key findings identified throughout the development process that shaped the MobileMums program were the need for: behaviour change techniques to be grounded in Social Cognitive Theory; tailored SMS content; two-way SMS interaction; rapport between SMS sender and recipient; an automated software platform to generate and send SMS; and, flexibility in location of a face-to-face delivered component. Conclusions The final version of MobileMums is flexible and adaptive to individual participant’s physical activity goals, expectations and environment. MobileMums is being evaluated in a community-based randomised controlled efficacy trial (ACTRN12611000481976). PMID:23256730

  4. 21 CFR 516.29 - Termination of MUMS-drug designation.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS NEW ANIMAL DRUGS FOR MINOR USE AND MINOR SPECIES Designation of a Minor Use or Minor Species New Animal Drug § 516.29 Termination of MUMS-drug designation. (a... exclusive marketing rights under this subpart. (d) FDA may terminate designation if it...

  5. Status of Health and Physical Education in Louisiana Public Schools: Grades 6-12, 1987. Research Bulletin 1811.

    ERIC Educational Resources Information Center

    Brightwell, D. Shelby; Dugas, Edmond A.

    This study focused on all teachers, in the public schools of Louisiana in grades 6-12, who taught health and physical education at least 50 percent of the time. A 53 percent return was obtained, which represented 917 teachers in 381 schools. Responses were received from all 64 parishes and the two city school systems in the state. The study…

  6. Immunogenicity and safety of a trivalent inactivated 2010-2011 influenza vaccine in Taiwan infants aged 6-12 months.

    PubMed

    Hwang, Kao-Pin; Hsu, Yu-Lung; Hsieh, Tsung-Hsueh; Lin, Hsiao-Chuan; Yen, Ting-Yu; Wei, Hsiu-Mei; Lin, Hung-Chih; Chen, An-Chyi; Chow, Julie Chi; Huang, Li-Min

    2014-05-01

    This prospective study aimed to investigate the immune responses and safety of an influenza vaccine in vaccine-naïve infants aged 6-12 months, and was conducted from November 2010 to May 2011. Fifty-nine infants aged 6-12 months received two doses of trivalent inactivated influenza vaccine 4 weeks apart. Hemagglutination inhibition titers were measured 4 weeks after the two doses of study vaccine. Based on the assumption that a hemagglutination inhibition titer of 1:40 or greater against the antigen would be protective in adults, two doses of the study vaccine generated a protective immune response of 63.2% against influenza A(H1N1), 82.5% against influenza A(H3N2) and 38.6% against influenza B viruses in infants aged 6-12 months. The geometric mean fold rises against influenza type A and B viruses also met the European Medicines Agency criteria for flu vaccines. The solicited events within 7 days after vaccination were mild in intensity. No deaths or adverse events such as optic neuritis, cranial neuropathy, and brachial neuropathy or Guillain-Barre syndrome were reported. Two doses of inactivated influenza vaccine were well tolerated and induced a protective immune response against influenza in infants aged 6-12 months.

  7. Rio Blanco: Land Use in a Highland Guatemalan Village. A Precollegiate Curriculum Unit: Grades 6-12. Revised.

    ERIC Educational Resources Information Center

    Stanford Univ., CA. Stanford Program on International and Cross Cultural Education.

    This unit, developed for grades 6-12, is designed to help students grasp what life is like in a highland village in Guatemala. It is intended that students develop skills in geography and begin to discuss such ideas as rural poverty, migration to urban centers, land distribution, and agricultural methods. The unit involves the use of a set of…

  8. Extragalactic stellar populations in the near and mid-infrared: 1-30 mum emission from evolved populations, young and dusty star forming regions and the earliest stellar populations

    NASA Astrophysics Data System (ADS)

    Mentuch, Erin

    2010-11-01

    The near- through mid-infrared offers a unique and, as this thesis aims to show, essential view of extragalactic stellar populations both nearby, at intermediate redshifts and at very high redshift. In chapter 2, I demonstrate that rest-frame near-IR photometry obtained by the Spitzer Space Telescope provides more robust stellar mass estimates for a spectroscopic sample of ˜ 100 galaxies in the redshift desert (0:5 < z < 2), and is crucial for modeling galaxies with young star-forming populations. From this analysis, a surprising result emerges in the data. Although the rest-frame light short of 2 mum improves stellar mass estimates, the models and observations disagree beyond 2 mum and emission from non-stellar sources becomes significant. At wavelengths from 1--30 mum, stellar and non-stellar emission contribute equally to a galaxy's global spectral energy distribution. This is unlike visible wavelengths where stellar emission dominates or the far-IR where dust emission provides the bulk of a galaxy's luminosity. Using the sample of high-z galaxies, in chapter 3, I quantify the statistical significance of the excess emission at 2-5 mum and find the emission to correlate with the O II luminosity, suggesting a link between the excess emission and star formation. The origin of the excess emission is not clear, although I explore a number of non-stellar candidates in this chapter. Nearby resolved observations provide a clearer picture of the excess by spatially resolving 68 nearby galaxies. By analyzing the pixel-by-pixel near-IR colours within each galaxy at ˜1-5 mum, increasingly red near-IR colors are mapped to spatial regions in chapter 4. For regions with red NIR colors and high star formation rates, I find the broad near- through mid-IR spectrum is constant, varying only in amplitude as a function of the intensity of star formation, suggesting the infrared emission of a young, dusty stellar populations can be added to stellar population synthesis models as an

  9. Short wavelength laser

    DOEpatents

    Hagelstein, P.L.

    1984-06-25

    A short wavelength laser is provided that is driven by conventional-laser pulses. A multiplicity of panels, mounted on substrates, are supported in two separated and alternately staggered facing and parallel arrays disposed along an approximately linear path. When the panels are illuminated by the conventional-laser pulses, single pass EUV or soft x-ray laser pulses are produced.

  10. Wavelength dependent delay in the onset of FEL tissue ablation

    SciTech Connect

    Tribble, J.A.; Edwards, G.S.; Lamb, J.A.

    1995-12-31

    We are investigating the wavelength dependence of the onset of laser tissue ablation in the IR Visible and UV ranges. Toward this end, we have made simultaneous measurements of the ejected material (using a HeNe probe beam tangential to the front surface) and the residual stress transient in the tissue (using traditional piezoelectric detection behind the thin samples). For the IR studies we have used the Vanderbilt FEL and for the UV and Vis range we have used a Q-switched ND:Yag with frequency doubling and quadrupling. To satisfy the conditions of the near field limit for the detection of the stress transient, the duration of the IR FEL macropulse must be as short as possible. We have obtained macropulses as short as 100 ns using Pockels Cell technology. The recording of the signals from both the photodiode monitoring the HeNe probe beam and the acoustic detector are synchronized with the arrival of the 100 ns macropulse. With subablative intensities, the resulting stress transient is bipolar with its positive peak separated from its negative peak by 100 ns in agreement with theory. Of particular interest is the comparison of ablative results using 3 {mu}m and 6.45 {mu}m pulses. Both the stress transient and the ejection of material suffer a greater delay (with respect to the arrival of the 100 ns pulse) when the FEL is tuned to 3 {mu}m as compared to 6.45 {mu}m. A comparison of IR Vis and UV data will be discussed in terms of microscopic mechanisms governing the laser ablation process.

  11. Long wavelength vertical-cavity light-emitting devices

    NASA Astrophysics Data System (ADS)

    Christenson, Gina Lee

    Long wavelength tunable transmitters are essential in the field of optical communications. Wavelength control and cost reduction are very important issues, especially in applications such as wavelength division multiplexing (WDM) networks, where several closely spaced wavelengths are transmitted and processed simultaneously. This thesis introduces a transmitter design that can alleviate these problems. This work involves the development, fabrication, and characterization of a narrowband tunable resonant cavity light-emitting diode (LED). The emission is centered at 1.51 mum, an important wavelength for optical communications. The linewidth is only 4 nm and the tuning range covers 75 nm. Wafer bonding and surface micromachining techniques have been integrated in the design to produce a structure that combines the assets of each technology. Wafer bonding is used to build the base for a vertical cavity surface emitting laser (VCSEL) structure, which is composed of an InP-based active layer on a GaAs-based mirror. Surface micromachining is then used to fabricate the suspended top mirror of the VCSEL, in place of the traditional top mirror that is grown directly on the VCSEL structure. The suspended mirror moves towards the substrate with the application of a voltage, thus changing the Fabry-Perot cavity length and providing the wavelength tunability of the device. This transmitter design relaxes the need for preset wavelengths in VCSEL processing by allowing the user to adjust the central wavelength after processing. Arrays of transmitters with identical wavelengths for high power applications or with gradually decreasing emission wavelengths across a wafer can also be achieved. The tunability of the devices allows for real time wavelength monitoring and tracking to ensure stability of the wavelengths with temperature or environmental changes, as well as compensating for shifts in wavelength due to degradation of the devices over time. Due to the monolithic, vertical

  12. Self-assembled InAs quantum wire lasers on (001)InP at 1.6 {mu}m

    SciTech Connect

    Suarez, F.; Fuster, D.; Gonzalez, L.; Gonzalez, Y.; Garcia, J. M.; Dotor, M. L.

    2006-08-28

    In this work, the authors present results on the growth by atomic layer molecular beam epitaxy and characterization of lasers with one and three stacked layers of InAs quantum wires (QWRs) as active zone and aluminum-free waveguides on (001) InP substrates. The separated confinement heterostructure consists of n-p InP claddings and a waveguide formed by short period superlattices of (InP){sub 5}/(GaInAs){sub 4} lattice matched to the InP substrate. The optimum growth conditions (substrate temperature and As and P pressures) have been determined to obtain waveguides with a flat surface in order to get a uniform QWR distribution. Lasing emission is observed at a wavelength of {approx}1.66 {mu}m up to 270 K from 15x3000 {mu}m{sup 2} devices, with a threshold current density at that temperature of 2 kA/cm{sup 2}.

  13. 0.4-1.4 {mu}m Visible to Near-Infrared Widely Broadened Super Continuum Generation with Er-doped Ultrashort Pulse Fiber Laser System

    SciTech Connect

    Nishizawa, Norihiko; Sumimura, Kazuhiko; Mitsuzawa, Hideyuki

    2009-03-17

    Visible to near-infrared widely broadened super continuum generation is demonstrated using ultrashort-pulse fiber laser system. Er-doped fiber chirped-pulse amplification system operated at 1550 nm in wavelength is used for the amplifier system, which generated ultrashort-pulse of 112 fs in FWHM with output power of 160 mW, on average. Almost pedestal free 200 fs second harmonic generation pulse is generated at 780 nm region using periodically poled LiNbO{sub 3} and conversion efficiency is as high as 37%. 0.45-1.40 {mu}m widely broadened super continuum is generated in highly nonlinear photonic crystal fiber and spectrum flatness is within {+-}6 dB. All of the fiber devices are fusion spliced so that this system shows a good stability.

  14. Switching of the photonic band gap in three-dimensional film photonic crystals based on opal-VO{sub 2} composites in the 1.3-1.6 {mu}m spectral range

    SciTech Connect

    Pevtsov, A. B. Grudinkin, S. A.; Poddubny, A. N.; Kaplan, S. F.; Kurdyukov, D. A.; Golubev, V. G.

    2010-12-15

    The parameters of three-dimensional photonic crystals based on opal-VO{sub 2} composite films in the 1.3-1.6 {mu}m spectral range important for practical applications (Telecom standard) are numerically calculated. For opal pores, the range of filling factors is established (0.25-0.6) wherein the composite exhibits the properties of a three-dimensional insulator photonic crystal. On the basis of the opal-VO{sub 2} composites, three-dimensional photonic film crystals are synthesized with specified parameters that provide a maximum shift of the photonic band gap in the vicinity of the wavelength {approx}1.5 {mu}m ({approx}170 meV) at the semiconductor-metal transition in VO{sub 2}.

  15. Optical fibre with a germanate glass core for lasing near 2 {mu}m

    SciTech Connect

    Dvoirin, Vladislav V; Mashinskii, Valerii M; Iskhakova, L D; Dianov, Evgenii M; Yashkov, M V; Khopin, V F; Gur'yanov, Aleksei N

    2011-01-24

    An optical fibre with a core based on thulium-doped germanate glass (45SiO{sub 2} - 55GeO{sub 2}) and a quartz glass cladding is developed for the first time. Lasing on Tm{sup 3+} ions ({lambda} =1.862 {mu}m) with an output power up to 70 mW at a differential efficiency of 37% is obtained in a laser based on this fibre. (letters)

  16. Short wavelength laser

    DOEpatents

    Hagelstein, Peter L.

    1986-01-01

    A short wavelength laser (28) is provided that is driven by conventional-laser pulses (30, 31). A multiplicity of panels (32), mounted on substrates (34), are supported in two separated and alternately staggered facing and parallel arrays disposed along an approximately linear path (42). When the panels (32) are illuminated by the conventional-laser pulses (30, 31), single pass EUV or soft x-ray laser pulses (44, 46) are produced.

  17. The effect of excitation wavelength on dynamics of laser-produced tin plasma

    SciTech Connect

    Harilal, S. S.; Sizyuk, T.; Hassanein, A.; Campos, D.; Sizyuk, V.; Hough, P.

    2011-03-15

    We investigated the effect of the excitation wavelength on the density evolution of laser-produced tin plasmas, both experimentally and numerically. For producing plasmas, Sn targets were excited with either 10.6 {mu}m CO{sub 2} laser or 1.06 {mu}m Nd:yttrium aluminum garnet laser; both are considered to be potential excitation lasers for extreme ultraviolet lithography laser-produced plasma light sources. The electron density of the plasma during the isothermal expansion regime was estimated using an interferometric technique. The Stark broadening of isolated singly-ionized emission was employed for deducing the density during the plasma adiabatic expansion regime. Our results indicate that the excitation source wavelength determines the initial density of the plasma, as well the plume expansion dynamics. Numerical simulation using HEIGHTS simulation package agrees well with the experimentally measured density profile.

  18. Spectral-kinetic properties of heterostructures with GaAsSb/InGaAs/GaAs-based quantum wells emitting in the range of 1.0-1.2 {mu}m

    SciTech Connect

    Morozov, S. V. Kryzhkov, D. I.; Aleshkin, V. Ya.; Zvonkov, B. N.; Vikhrova, O. I.

    2013-11-15

    The spectral-kinetic properties of heterostructures with GaAs/GaAsSb-based and GaAsSb/InGaAs/GaAs-based quantum wells, emitting in the range of 1.0-1.2 {mu}m are studied with picosecond and nanosecond temporal resolution. Intense photoluminescence in the GaAsSb/InGaAs/GaAs structure, as well as an increase in the photoluminescence wavelength by a factor of 2.5 and a shift of the location of the maximum of the peak ({approx}100 meV) to the longer-wavelength region were observed up to room temperature. It is established that as the molar fraction of Sb and the thickness of the InGaAs layer increase, the energy of the fundamental transition decreases by a factor of 140 meV compared with the GaAsSb/InGaAs/GaAs structure with a lower Sb content and a smaller thickness of the InGaAs layer. At 300 K, the emission wavelength of such a structure was 1.18 {mu}m. In addition, an increase in the thickness of the InGaAs layer led to an increase in the room-temperature photoluminescence intensity by a factor of 60, which is associated with a decrease in the energy of the fundamental state for electrons in the InGaAs layer and, consequently, to larger electron localization and smaller temperature quenching of photoluminescence.

  19. Densification of silica glass induced by 0.8 and 1.5 {mu}m intense femtosecond laser pulses

    SciTech Connect

    Saliminia, A.; Nguyen, N.T.; Chin, S.L.; Vallee, R.

    2006-05-01

    We investigate the physical mechanisms responsible for waveguide formation in silica glass induced by 1 kHz intense femtosecond laser pulses from a Ti-sapphire laser at 0.8 {mu}m as well as from a femtosecond optical parametric amplifier at 1.5 {mu}m. It is demonstrated that the densification taking place at the irradiated region is the principal cause for refractive index change in the waveguides written with both 0.8 and 1.5 {mu}m pulses. The birefringence induced by the stress arising from such densification and its behavior against thermal annealing are also studied.

  20. Wavelength meter having elliptical wedge

    DOEpatents

    Hackel, R.P.; Feldman, M.

    1992-12-01

    A wavelength meter is disclosed which can determine the wavelength of a laser beam from a laser source within an accuracy range of two parts in 10[sup 8]. The wavelength meter has wedge having an elliptically shaped face to the optical path of the laser source and includes interferometer plates which form a vacuum housing. 7 figs.

  1. Wavelength meter having elliptical wedge

    DOEpatents

    Hackel, Richard P.; Feldman, Mark

    1992-01-01

    A wavelength meter is disclosed which can determine the wavelength of a laser beam from a laser source within an accuracy range of two parts in 10.sup.8. The wavelength meter has wedge having an elliptically shaped face to the optical path of the laser source and includes interferometer plates which form a vacuum housing.

  2. Fabrication of 3-{mu}m diameter pin hole array (PHA) on thick W substrates

    SciTech Connect

    Levato, T.; Pathak, N. C.; Ciricosta, O.; Cecchetti, C. A.; Koester, P.; Labate, L.; Giulietti, A.; Gizzi, L. A.; Giulietti, D.; De Angelis, F.; Di Fabrizio, E.; Delogu, P.

    2010-02-02

    Pin-hole arrays are used for a variety of applications including, for example, X-ray imaging of laser-plasmas for fusion relevant studies. More recently, a novel X-ray imaging technique has been proposed (this conference L. A. Gizzi et al.) within the High Power Laser Energy Research Facility (HiPER) to obtain spectrally resolved X-ray imaging using single photon detection. This technique requires a large number of images or, alternatively, large arrays of pin-holes, possibly with very small diameter (<<10 {mu}m). In view of this, a technique was implemented for the fabrication of large arrays of pin-holes in thick metal substrates. Here we report on the optimizations of the laser-matter interaction process to obtain high aspect ratio cylinder-like pin-hole on heavy metal substrate by using a frequency-doubled Ti:Sa femtosecond laser pulses operating at 10 Hz. The influence of an air breakdown and a (ns)prepulse, on the drilled pin-hole, is showed by means of SEM images both for surface effects and internal quality of the channels, with evidence of micro and nano-sized structures. The holes drilled at an intensity just below the laser breakdown threshold for plasma creation in air, have an internal diameter of about 3 {mu}m on a W substrate of 70 {mu}m thickness, a micro-cylinder-like shape and no detectable deviations of the axis from a straight line. Arrays of up to 800 pin-holes were produced with the pin-hole properties being highly stable across the array. The final X-ray transmission is showed by using a mu-focus X-ray source.

  3. Remote Mapping of Vegetation and Geological Features by Lidar in the 9-11-mum Region.

    PubMed

    Foy, B R; McVey, B D; Petrin, R R; Tiee, J J; Wilson, C W

    2001-08-20

    We report examples of the use of a scanning tunable CO(2) laser lidar system in the 9-11-mum region to construct images of vegetation and rocks at ranges as far as 5 km from the instrument. Range information is combined with horizontal and vertical distances to yield an image with three spatial dimensions simultaneous with the classification of target type. Object classification is based on reflectance spectra, which are sufficiently distinct to allow discrimination between several tree species, between trees and scrub vegetation, and between natural and artificial targets. Limitations imposed by laser speckle noise are discussed. PMID:18360475

  4. The effects of slipage and diffraction in long wavelength operation of a free electron laser

    SciTech Connect

    Zhulin, V.I.; Haselhoff, E.H.; Amersfoort, P.W. van

    1995-01-01

    The Free-Electron Laser user facility FELIX produces picosecond optical pulses in the wavelength range of 5-110 {mu}m. The proposed installation of a new undulator with a larger magnetic period would allow extension towards considerably larger wavelengths. This would result in the production of extremely short, far-infrared pulses, with a duration of a single optical period or even less. In order to investigate the pulse propagation for free-electron lasers operating in the long wavelength limit, a three-dimensional simulation code was developed. Using the FELIX parameters, with the addition of a long-period undulator, the effects of slippage, diffraction losses, changes in the filling factor, as well as the effects of the optical cavity geometry were studied for wavelengths up to 300 {mu}m, with electron pulses in the ps regime. It is shown that slippage effects are less restrictive for long wavelength operation than the increasing losses due to optical beam diffraction.

  5. CO STRUCTURE OF THE 21 {mu}m SOURCE IRAS 22272+5435: A SIGN OF A JET LAUNCH?

    SciTech Connect

    Nakashima, Jun-ichi; Kwok, Sun; Yung, Bosco H. K.; Zhang Yong; Koning, Nico; Volgenau, Nikolaus H.

    2012-11-01

    We report the results of radio interferometric observations of the 21 {mu}m source IRAS 22272+5435 in the CO J = 2-1 line. 21 {mu}m sources are carbon-rich objects in the post-asymptotic-giant-branch phase of evolution, which show an unidentified emission feature at 21 {mu}m. Since 21 {mu}m sources usually also have circumstellar molecular envelopes, the mapping of CO emission from the envelope will be useful in tracing the nebular structure. From observations made with the Combined Array for Research in Millimeter-wave Astronomy, we find that a torus and spherical wind model can explain only part of the CO structure. An additional axisymmetric region created by the interaction between an invisible jet and ambient material is suggested.

  6. Growth of 1.3 {mu}m InGaAsN laser material on GaAs by molecular beam epitaxy

    SciTech Connect

    Mars, D.E.; Babic, D.I.; Kaneko, Y.; Chang, Y.; Subramanya, S. |; Kruger, J.; Perlin, P.; Weber, E.R.

    1999-05-01

    We have grown bulk GaAsN and InGaAsN quantum well laser structures using molecular beam epitaxy and an electron cyclotron resonance plasma source with N{sub 2} gas. X-ray diffraction measurements in GaAsN grown on GaAs were used to determine the concentration of N in the range of 0{percent} to {approximately}2{percent}. Room temperature photoluminescence (PL) measurements were done on quantum well test structures and half lasers. The PL intensity decreases and the PL full width at half maximum (FWHM) increases as the wavelength increases. Rapid thermal annealing (RTA) at 850&hthinsp;{degree}C for 10 s improves the PL intensity by a factor of 8 and increases the PL peak emission energy by 80 meV. The longest wavelength measured to date in laser structures with single quantum wells of InGaAsN is 1480 nm with a FWHM of 60 meV. Samples with and without RTA were fabricated into broad-area lasers with dimensions of 50{times}500&hthinsp;{mu}m{sup 2}. Laser devices with RTA operated in the pulsed mode at 1.3 {mu}m with a threshold current density of 9.5 kA/cm{sup 2}. {copyright} {ital 1999 American Vacuum Society.}

  7. Quadrature wavelength scanning interferometry.

    PubMed

    Moschetti, Giuseppe; Forbes, Alistair; Leach, Richard K; Jiang, Xiang; O'Connor, Daniel

    2016-07-10

    A novel method to double the measurement range of wavelength scanning interferometery (WSI) is described. In WSI the measured optical path difference (OPD) is affected by a sign ambiguity, that is, from an interference signal it is not possible to distinguish whether the OPD is positive or negative. The sign ambiguity can be resolved by measuring an interference signal in quadrature. A method to obtain a quadrature interference signal for WSI is described, and a theoretical analysis of the advantages is reported. Simulations of the advantages of the technique and of signal errors due to nonideal quadrature are discussed. The analysis and simulation are supported by experimental measurements to show the improved performances. PMID:27409307

  8. Comets at radio wavelengths

    NASA Astrophysics Data System (ADS)

    Crovisier, Jacques; Bockelée-Morvan, Dominique; Colom, Pierre; Biver, Nicolas

    2016-11-01

    Comets are considered as the most primitive objects in the Solar System. Their composition provides information on the composition of the primitive solar nebula, 4.6 Gyr ago. The radio domain is a privileged tool to study the composition of cometary ices. Observations of the OH radical at 18 cm wavelength allow us to measure the water production rate. A wealth of molecules (and some of their isotopologues) coming from the sublimation of ices in the nucleus have been identified by observations in the millimetre and submillimetre domains. We present an historical review on radio observations of comets, focusing on the results from our group, and including recent observations with the Nançay radio telescope, the IRAM antennas, the Odin satellite, the Herschel space observatory, ALMA, and the MIRO instrument aboard the Rosetta space probe. xml:lang="fr"

  9. Efficient GaInNAs Gain Mirrors for Semiconductor Disk Lasers at 1.18 {mu}m and 1.22 {mu}m

    SciTech Connect

    Korpijaervi, Ville-Markus; Puustinen, Janne; Leinonen, Tomi; Rautiainen, Jussi; Haerkoenen, Antti; Hakkarainen, Teemu; Guina, Mircea

    2010-11-10

    We report two GaInNAs/GaAs semiconductor disk lasers emitting at the wavelengths of 1180 nm and 1220 nm. The lasers generated 5 W and 7 W output powers, respectively, at a mount temperature of 15 deg. C. Both the gain mirrors were grown by molecular beam epitaxy and consisted of a GaAs/AlAs distributed Bragg reflector and an active region with 10 GaInNAs/GaNAs/GaAs QWs.

  10. [Cr(III)8M(II)6](12+) Coordination Cubes (M(II)=Cu, Co).

    PubMed

    Sanz, Sergio; O'Connor, Helen M; Pineda, Eufemio Moreno; Pedersen, Kasper S; Nichol, Gary S; Mønsted, Ole; Weihe, Høgni; Piligkos, Stergios; McInnes, Eric J L; Lusby, Paul J; Brechin, Euan K

    2015-06-01

    [Cr(III)8M(II)6](12+) (M(II) =Cu, Co) coordination cubes were constructed from a simple [Cr(III) L3 ] metalloligand and a "naked" M(II) salt. The flexibility in the design proffers the potential to tune the physical properties, as all the constituent parts of the cage can be changed without structural alteration. Computational techniques (known in theoretical nuclear physics as statistical spectroscopy) in tandem with EPR spectroscopy are used to interpret the magnetic behavior.

  11. Polarized thermal radiation by layer-by-layer metallic emitters with sub-wavelength grating.

    PubMed

    Lee, Jae-Hwang; Leung, Wai; Kim, Tae Guen; Constant, Kristen; Ho, Kai-Ming

    2008-06-01

    Metallic thermal emitters consisting of two layers of differently structured nickel gratings on a homogeneous nickel layer are fabricated by soft lithography and studied for polarized thermal radiation. A thermal emitter in combination with a sub-wavelength grating shows a high extinction ratio, with a maximum value close to 5, in a wide mid-infrared range from 3.2 to 7.8 mum, as well as high emissivity up to 0.65 at a wavelength of 3.7 microm. All measurements show good agreement with theoretical predictions. Numerical simulations reveal that a high electric field exists within the localized air space surrounded by the gratings and the intensified electric-field is only observed for the polarizations perpendicular to the top sub-wavelength grating. This result suggests how the emissivity of a metal can be selectively enhanced at a certain range of wavelengths for a given polarization. PMID:18545587

  12. Airbreathing Laser Propulsion Experiments with 1 {mu}m Terawatt Pharos III Laser: Part 1

    SciTech Connect

    Myrabo, L. N.; Lyons, P. W.; Jones, R. A.; Liu, S.; Manka, C.

    2011-11-10

    This basic research study examines the physics of airbreathing laser propulsion at the extreme flux range of 1-2x10{sup 11} W/cm{sup 2}--within the air breakdown threshold for l {mu}m radiation--using the terawatt PHAROS III neodymium-glass pulsed laser. Six different experimental setups were tested using a 34 mm line focus with 66 {mu}m focal waist, positioned near the flat impulse surface. The first campaign investigated impulse generation with the beam oriented almost normal to the target surface, with energies ranging from 23 to 376 J, and pulses of 5 to 30 ns FWHM. Air breakdown/ plasma dynamics were diagnosed with GOI cameras and color photography. Laser generated impulse was quantified with both vertical pendulums and piezoelectric pressure transducers using the standard performance metric, C{sub M}--the momentum coupling coefficient. Part 1 of this 2-part paper covers Campaign no. 1 results including laser plasma diagnostics, pressure gage and vertical pendulum data.

  13. Airbreathing Laser Propulsion Experiments with 1 {mu}m Terawatt Pharos IIILaser: Part 2

    SciTech Connect

    Myrabo, L. N.; Lyons, P. W.; Jones, R. A.; Liu, S.; Manka, C.

    2011-11-10

    This basic research study examines the physics of airbreathing laser propulsion at the extreme flux range of 1-2x10{sup 11} W/cm{sup 2}--within the air breakdown threshold for l {mu}m radiation--using the terawatt Pharos III neodymium-glass pulsed laser. Six different experimental setups were employed using a 34 mm line focus with 66 {mu}m focal waist, positioned near the flat impulse surface. The 2nd Campaign investigated impulse generation with the laser beam focused at grazing incidence across near horizontal target surfaces, with pulse energies ranging from 55 to 186 J, and pulse-widths of 2 to 30 ns FWHM. Laser generated impulse was measured with a horizontal Plexiglas registered ballistic pendulum equipped with either a steel target insert or 0.5 Tesla permanent magnet (NEIT-40), to quantify changes in the momentum coupling coefficient (C{sub M}). Part 2 of this 2-part paper covers Campaign no. 2 results including C{sub M} performance data, and long exposure color photos of LP plasma phenomena.

  14. Internal to external wavelength calibration

    NASA Astrophysics Data System (ADS)

    Sahu, Kailash C.

    1999-01-01

    The spectra of Hen 1357 (the Stingray nebula) were used to check the internal to external wavelength calibration of the STIS first order CCD modes. The radial velocity of the Stingray nebula is known to high accuracy (< 1 km/sec) and the line with of the nebular line is very narrow (< 8 km/sec for the integrated nebula). Thus the observations of the Stingray nebula are ideal to check the internal to external wavelength calibration of the first order modes. The observations were taken in G430L and G750M modes using a 52 x 0.05 arcsec slit covering the wavelength range 2900 to 5700 A and 6295 to 6867 A, respectively. The observed wavelength range includes many nebular emission lines. The wavelengths of the nebular lines derived using the pipeline internal wavelength calibration were compared with the wavelengths derived from other ground based observations. In all cases, the wavelength match between the two is of the same order as the accuracy to which the line center can be measured. These results imply that there is no significant offset between the internal and external wavelength calibrations for these modes. The HDF-S QSO observations were also used for this test both for the first order and the Echelle modes. The results of the HDF-S QSO observations further confirm the above finding for the first order modes, and imply that there is no significant offset between the internal and external wavelength calibration for the Echelle modes.

  15. Wavelength-conserving grating router for intermediate wavelength density

    DOEpatents

    Deri, Robert J.; Patel, Rajesh R.; Bond, Steven W.; Bennett, Cory V.

    2007-03-20

    A wavelength router to be used for fiber optical networking router is based on a diffraction grating which utilizes only N wavelengths to interconnect N inputs to N outputs. The basic approach is to augment the grating with additional couplers or wavelength selective elements so than N-1 of the 2N-1 outputs are combined with other N outputs (leaving only N outputs). One embodiment uses directional couplers as combiners. Another embodiment uses wavelength-selective couplers. Another embodiment uses a pair of diffraction gratings to maintain parallel propagation of all optical beams. Also, beam combining can be implemented either by using retroflection back through the grating pair or by using couplers.

  16. UK AMD EMR USERS GROUP REPORT V: benefits of initiating ranibizumab therapy for neovascular AMD in eyes with vision better than 6/12

    PubMed Central

    Lee, Aaron Y; Lee, Cecilia S; Butt, Thomas; Xing, Wen; Johnston, Robert L; Chakravarthy, Usha; Egan, Catherine; Akerele, Toks; McKibbin, Martin; Downey, Louise; Natha, Salim; Bailey, Clare; Khan, Rehna; Antcliff, Richard; Varma, Atul; Kumar, Vineeth; Tsaloumas, Marie; Mandal, Kaveri; Liew, Gerald; Keane, Pearse A; Sim, Dawn; Bunce, Catey; Tufail, Adnan

    2015-01-01

    Background/aims To study the effectiveness and clinical relevance of eyes treated with good (better than 6/12 or >70 Early Treatment Diabetic Retinopathy Study letters) visual acuity (VA) when initiating treatment with ranibizumab for neovascular age-related macular degeneration (nAMD) in the UK National Health Service. Currently eyes with VA better than (>) 6/12 are not routinely funded for therapy. Methods Multicentre national nAMD database study on patients treated 3–5 years prior to the analysis. Anonymised structured data were collected from 14 centres. The primary outcome was the mean VA at year 1, 2 and 3. Secondary measures included the number of clinic visits and injections. Results The study included 12 951 treatment-naive eyes of 11 135 patients receiving 92 976 ranibizumab treatment episodes. A total of 754 patients had baseline VA better than 6/12 and at least 1-year of follow up. Mean VA of first treated eyes with baseline VA>6/12 at year 1, 2, 3 were 6/10, 6/12, 6/15, respectively and those with baseline VA 6/12 to >6/24 were 6/15, 6/17, 6/20, respectively (p values <0.001 for comparing differences between 6/12 and 6/12–6/24 groups). For the second eyes with baseline VA>6/12, mean VA at year 1, 2, 3 were 6/9, 6/9, 6/10 and those with baseline VA 6/12 to >6/24 were 6/15, 6/15, 6/27, respectively (p values <0.001–0.005). There was no significant difference in the average number of clinic visits or injections between those with VA better and worse than 6/12. Conclusions All eyes with baseline VA>6/12 maintained better mean VA than the eyes with baseline VA 6/12 to >6/24 at all time points for at least 2 years. The significantly better visual outcome in patients who were treated with good baseline VA has implications on future policy regarding the treatment criteria for nAMD patients’ funding. PMID:25680619

  17. Epitaxial approaches to long-wavelength vertical-cavity lasers

    NASA Astrophysics Data System (ADS)

    Hall, Eric Michael

    The success of short-wavelength (850 nm) vertical-cavity surface-emitting lasers (VCSELs) as low-cost components in fiber optic networks has created a strong demand for similar low-cost devices at longer wavelengths (1.3--1.55mum), which are even more important in telecommunications systems. Extending the success of VCSELs to these longer wavelengths, however, has been slowed by the absence of a mature technology that incorporates all of the necessary components on one substrate without sacrificing the inexpensive and manufacturable nature of VCSELs. Although InAlGaAs active regions on InP substrates have been developed extensively, the other components of vertical-cavity lasers, especially epitaxially-grown distributed Bragg reflectors (DBRs), are less mature on these substrates. This thesis examines the materials and technologies that enable long-wavelength VCSELs to be grown in a single, epitaxial, lattice-matched step on InP substrates. The advantages and shortcomings of each material system are identified and the impact on devices examined. Additionally, processing technologies that rely on the properties of these materials are developed. From these studies, a InP-based, lattice-matched VCSEL design is presented that utilizes AlGaAsSb for high reflectivity DBRs, InAlGaAs for high quality active regions, InP for heat and current spreading, and a materials selective etch for electrical and optical confinement. In short, the design avoids the shortcomings of each material system while emphasizing the advantages. The resulting devices, showing low threshold currents, high efficiencies and powers, and high operating temperatures, not only validate this approach but demonstrate that such lattice-matched, InP-based devices may be a low-cost, manufacturable answer to this long-wavelength VCSEL demand.

  18. THE CIRCULAR POLARIZATION OF SAGITTARIUS A* AT SUBMILLIMETER WAVELENGTHS

    SciTech Connect

    Munoz, D. J.; Moran, J. M.; Marrone, D. P.; Rao, R.

    2012-02-01

    We report the first detections of circularly polarized emission at submillimeter wavelengths from the compact radio source and supermassive black hole candidate Sgr A* at a level of 1.2% {+-} 0.3% at 1.3 mm wavelength (230 GHz) and 1.6% {+-} 0.3% at 860 {mu}m (345 GHz) with the same handedness, left circular polarization (LCP), as observed at all lower frequencies (1.4-15 GHz). The observations, taken with the Submillimeter Array in multiple epochs, also show simultaneous linear polarization (LP) at both wavelengths of about 6%. These properties differ sharply from those at wavelengths longer than 1 cm (frequencies below 30 GHz), where weak circular polarization (CP) ({approx}0.5%) dominates over LP, which is not detected at similar fractional limits. We describe an extensive set of tests to ensure the accuracy of our measurements. We find no CP in any other source, including the bright quasar 1924-292, which traces the same path on the sky as Sgr A* and therefore should be subject to identical systematic errors originating in the instrument frame. Since a relativistic synchrotron plasma is expected to produce little CP, the observed CP is probably generated close to the event horizon by the Faraday conversion process. We use a simple approximation to show that the phase shift associated with Faraday conversion can be nearly independent of frequency, a sufficient condition to make the handedness of CP independent of frequency. Because the size of the {tau} = 1 surface changes by more than an order of magnitude between 1.4 and 345 GHz, the magnetic field must be coherent over such scales to consistently produce LCP. To improve our understanding of the environment of SgrA* critical future measurements includes determining whether the Faraday rotation deviates from a {lambda}{sup 2} dependence in wavelength and whether the circular and linear components of the flux density are correlated.

  19. METHANOL MASER EMISSION FROM GALACTIC CENTER SOURCES WITH EXCESS 4.5 {mu}m EMISSION

    SciTech Connect

    Chambers, E. T.; Yusef-Zadeh, F.; Roberts, D. E-mail: zadeh@northwestern.edu

    2011-05-20

    We present a study of signatures of on-going star formation in a sample of protostellar objects with enhanced 4.5 {mu}m emission ('green' sources) near the Galactic center. To understand how star formation in the Galactic center region compares to that of the Galactic disk, we used the Expanded Very Large Array to observe radiatively excited Class II 6.7 GHz CH{sub 3}OH masers and collisionally excited Class I 44 GHz CH{sub 3}OH masers, both tracers of high-mass star formation, toward a sample of 34 Galactic center and foreground 'green' sources. We find that 33% {+-} 15% of Galactic center sources are coincident with 6.7 GHz masers, and that 44% {+-} 17% of foreground sources are coincident with 6.7 GHz masers. For 44 GHz masers, we find correlation rates of 27% {+-} 13% and 25% {+-} 13% for Galactic center green sources and foreground green sources, respectively. Based on these CH{sub 3}OH maser detection rates, as well as correlations of green sources with other tracers of star formation, such as 24 {mu}m emission and infrared dark clouds (IRDCs), we find no significant difference between the green sources in the Galactic center and those foreground to it. This suggests that once the star formation process has begun, the environmental differences between the Galactic center region and the Galactic disk have little effect on its observational signatures. We do find, however, some evidence that may support a recent episode of star formation in the Galactic center region.

  20. THE 8 {mu}m PHASE VARIATION OF THE HOT SATURN HD 149026b

    SciTech Connect

    Knutson, Heather A.; Charbonneau, David; Cowan, Nicolas B.; Agol, Eric; Fortney, Jonathan J.; Henry, Gregory W.

    2009-09-20

    We monitor the star HD 149026 and its Saturn-mass planet at 8.0 {mu}m over slightly more than half an orbit using the Infrared Array Camera on the Spitzer Space Telescope. We find an increase of 0.0227% +- 0.0066% (3.4sigma significance) in the combined planet-star flux during this interval. The minimum flux from the planet is 45% +- 19% of the maximum planet flux, corresponding to a difference in brightness temperature of 480 +- 140 K between the two hemispheres. We derive a new secondary eclipse depth of 0.0411% +- 0.0076% in this band, corresponding to a dayside brightness temperature of 1440 +- 150 K. Our new secondary eclipse depth is half that of a previous measurement (3.0sigma difference) in this same bandpass by Harrrington et al. We re-fit the Harrrington et al. data and obtain a comparably good fit with a smaller eclipse depth that is consistent with our new value. In contrast to earlier claims, our new eclipse depth suggests that this planet's dayside emission spectrum is relatively cool, with an 8 {mu}m brightness temperature that is less than the maximum planet-wide equilibrium temperature. We measure the interval between the transit and secondary eclipse and find that that the secondary eclipse occurs 20.9{sup +7.2}{sub -6.5} minutes earlier (2.9sigma) than predicted for a circular orbit, a marginally significant result. This corresponds to ecos(omega) = -0.0079{sup +0.0027}{sub -0.0025}, where e is the planet's orbital eccentricity and omega is the argument of pericenter.

  1. The Long Wavelength Array

    NASA Astrophysics Data System (ADS)

    Taylor, G. B.

    2006-08-01

    The Long Wavelength Array (LWA) will be a new, open, user-oriented astronomical instrument operating in the poorly explored window from 20-80 MHz at arcsecond level resolution and mJy level sensitivity. Key science drivers include (1) acceleration, propagation, and turbulence in the ISM, including the space-distribution and spectrum of Galactic cosmic rays, supernova remnants, and pulsars; (2) the high redshift universe, including the most distant radio galaxies and clusters - tools for understanding the earliest black holes and the cosmological evolution of Dark Matter and Dark Energy; (3) planetary, solar, and space science, including space weather prediction and extra-solar planet searches; and (4) the radio transient universe: including the known (e.g., SNe, GRBs) and the unknown. Because the LWA will explore one of the last and least investigated regions of the spectrum, the potential for new discoveries, including new classes of physical phenomena, is high, and there is a strong synergy with exciting new X-ray and Gamma-ray measurements, e.g. for cosmic ray acceleration, transients, and galaxy clusters. Operated by the University of New Mexico on behalf of the South West Consortium (SWC) the LWA will also provide a unique training ground for the next generation of radio astronomers. Students may also put skills learned on the LWA to work in computer science, electrical engineering, and the communications industry, among others. The development of the LWA will follow a phased build, which benefits from lessons learned at each phase. Four university-based Scientific Testing and Evaluation (ST&E) teams with different areas of concentration (1. High resolution imaging and particle acceleration; 2. Wide field imaging and large scale structures; 3. Ionosphere, and 4. RFI suppression and transient detection) will provide the feedback needed to assure that science objectives are met as the build develops. Currently in its first year of construction funding, the LWA

  2. Interference comparator for laser diode wavelength and wavelength instability measurement.

    PubMed

    Dobosz, Marek; Kożuchowski, Mariusz

    2016-04-01

    Method and construction of a setup, which allows measuring the wavelength and wavelength instability of the light emitted by a laser diode (or a laser light source with a limited time coherence in general), is presented. The system is based on Twyman-Green interferometer configuration. Proportions of phases of the tested and reference laser's interference fringe obtained for a set optical path difference are a measure of the unknown wavelength. Optical path difference in interferometer is stabilized. The interferometric comparison is performed in vacuum chamber. The techniques of accurate fringe phase measurements are proposed. The obtained relative standard uncertainty of wavelength evaluation in the tested setup is about 2.5 ⋅ 10(-8). Uncertainty of wavelength instability measurement is an order of magnitude better. Measurement range of the current setup is from 500 nm to 650 nm. The proposed technique allows high accuracy wavelength measurement of middle or low coherence sources of light. In case of the enlarged and complex frequency distribution of the laser, the evaluated wavelength can act as the length master in interferometer for displacement measurement. PMID:27131662

  3. Interference comparator for laser diode wavelength and wavelength instability measurement

    NASA Astrophysics Data System (ADS)

    Dobosz, Marek; KoŻuchowski, Mariusz

    2016-04-01

    Method and construction of a setup, which allows measuring the wavelength and wavelength instability of the light emitted by a laser diode (or a laser light source with a limited time coherence in general), is presented. The system is based on Twyman-Green interferometer configuration. Proportions of phases of the tested and reference laser's interference fringe obtained for a set optical path difference are a measure of the unknown wavelength. Optical path difference in interferometer is stabilized. The interferometric comparison is performed in vacuum chamber. The techniques of accurate fringe phase measurements are proposed. The obtained relative standard uncertainty of wavelength evaluation in the tested setup is about 2.5 ṡ 10-8. Uncertainty of wavelength instability measurement is an order of magnitude better. Measurement range of the current setup is from 500 nm to 650 nm. The proposed technique allows high accuracy wavelength measurement of middle or low coherence sources of light. In case of the enlarged and complex frequency distribution of the laser, the evaluated wavelength can act as the length master in interferometer for displacement measurement.

  4. Characterization of 2-mum DNA of Saccharomyces cerevisiae by restriction fragment analysis and integration in an Escherichia coli plasmid.

    PubMed Central

    Hollenberg, C P; Degelmann, A; Kustermann-Kuhn, B; Royer, H D

    1976-01-01

    Electrophoretic analysis of EcoRI and HindIII restriction fragments of 2-mum supercoiled DNA of Saccharomyces cerevisiae indicated that this class of DNA is heterogeneous and probably consists of two types of molecules. Integration of the 2-mum yeast DNA in E. coli plasmid pCR1 directly showed that existence of two types of molecules as each of these could be individually inserted into separate bacterial plasmids. The difference between the two types of 2-mum circles is due to an inversion of about 1.6 X 10(6) daltons. The inversion is flanked by a reversed duplicated sequence of 0.45 X 10(6) daltons. Possible implications of this structure are dicussed. Images PMID:778854

  5. Apparatus and method for generating continuous wave 16 .mu.m laser radiation using gaseous CF.sub.4

    DOEpatents

    Telle, John M.

    1986-01-01

    Apparatus and method for generating continuous wave 16 .mu.m laser radiation using gaseous CF.sub.4. Laser radiation at 16 .mu.m has been observed in a cooled static cell containing low pressure CF.sub.4 optically pumped by an approximately 3 W output power cw CO.sub.2 laser. The laser cavity employed was a multiple-pass off-axis-path two spherical mirror ring resonator. Unidirectional CF.sub.4 laser output power at 615 cm.sup.-1 exceeded 2 mW. Computer calculations indicate that for modest pump powers of about 40 W, approximately 1 W of emitted laser radiation at 16 .mu.m might be obtained.

  6. THE 0.8-14.5 {mu}m SPECTRA OF MID-L TO MID-T DWARFS: DIAGNOSTICS OF EFFECTIVE TEMPERATURE, GRAIN SEDIMENTATION, GAS TRANSPORT, AND SURFACE GRAVITY

    SciTech Connect

    Stephens, D. C.; Leggett, S. K.; Geballe, T. R.; Cushing, Michael C.; Marley, Mark S.; Saumon, D.; Golimowski, David A.; Noll, K. S.; Fan Xiaohui

    2009-09-01

    We present new 5.2-14.5 {mu}m low-resolution spectra of 14 mid-L to mid-T dwarfs. We also present new 3.0-4.1 {mu}m spectra for five of these dwarfs. These data are supplemented by existing red and near-infrared spectra ({approx}0.6-2.5 {mu}m), as well as red through mid-infrared spectroscopy of seven other L and T dwarfs presented by Cushing et al. We compare these spectra to those generated from the model atmospheres of Saumon and Marley. The models reproduce the observed spectra well, except in the case of one very red L3.5 dwarf, 2MASS J22244381-0158521. The broad wavelength coverage allows us to constrain almost independently the four parameters used to describe these photospheres in our models: effective temperature (T {sub eff}), surface gravity, grain sedimentation efficiency (f{sub sed}), and vertical gas transport efficiency (K{sub zz} ). The CH{sub 4} bands centered at 2.2, 3.3, and 7.65 {mu}m and the CO band at 2.3 {mu}m are sensitive to K{sub zz} , and indicates that chemical mixing is important in all L and T dwarf atmospheres. The sample of L3.5 to T5.5 dwarfs spans the range 1800 K{approx}> T{sub eff} {approx}>1000 K, with an L-T transition (spectral types L7 to T4) that lies between 1400 and 1100 K for dwarfs with typical near-infrared colors; bluer and redder dwarfs can be 100 K warmer or cooler, respectively, when using infrared spectral types. When using optical spectral types, the bluer dwarfs have more typical T {sub eff} values as they tend to have earlier optical spectral types. In this model analysis, f {sub sed} increases rapidly between types T0 and T4, indicating that increased sedimentation can explain the rapid disappearance of clouds at this stage of brown dwarf evolution. There is a suggestion that the transition to dust-free atmospheres happens at lower temperatures for lower gravity dwarfs.

  7. AWG Filter for Wavelength Interrogator

    NASA Technical Reports Server (NTRS)

    Black, Richard J. (Inventor); Costa, Joannes M. (Inventor); Faridian, Fereydoun (Inventor); Moslehi, Behzad (Inventor); Sotoudeh, Vahid (Inventor)

    2015-01-01

    A wavelength interrogator is coupled to a circulator which couples optical energy from a broadband source to an optical fiber having a plurality of sensors, each sensor reflecting optical energy at a unique wavelength and directing the reflected optical energy to an AWG. The AWG has a detector coupled to each output, and the reflected optical energy from each grating is coupled to the skirt edge response of the AWG such that the adjacent channel responses form a complementary pair response. The complementary pair response is used to convert an AWG skirt response to a wavelength.

  8. CONFIRMING THE PRIMARILY SMOOTH STRUCTURE OF THE VEGA DEBRIS DISK AT MILLIMETER WAVELENGTHS

    SciTech Connect

    Hughes, A. Meredith; Plambeck, Richard; Chiang, Eugene; Wilner, David J.; Andrews, Sean M.; Mason, Brian; Carpenter, John M.; Chiang, Hsin-Fang; Williams, Jonathan P.; Hales, Antonio; Su, Kate; Dicker, Simon; Korngut, Phil; Devlin, Mark

    2012-05-01

    Clumpy structure in the debris disk around Vega has been previously reported at millimeter wavelengths and attributed to concentrations of dust grains trapped in resonances with an unseen planet. However, recent imaging at similar wavelengths with higher sensitivity has disputed the observed structure. We present three new millimeter-wavelength observations that help to resolve the puzzling and contradictory observations. We have observed the Vega system with the Submillimeter Array (SMA) at a wavelength of 880 {mu}m and an angular resolution of 5''; with the Combined Array for Research in Millimeter-wave Astronomy (CARMA) at a wavelength of 1.3 mm and an angular resolution of 5''; and with the Green Bank Telescope (GBT) at a wavelength of 3.3 mm and angular resolution of 10''. Despite high sensitivity and short baselines, we do not detect the Vega debris disk in either of the interferometric data sets (SMA and CARMA), which should be sensitive at high significance to clumpy structure based on previously reported observations. We obtain a marginal (3{sigma}) detection of disk emission in the GBT data; the spatial distribution of the emission is not well constrained. We analyze the observations in the context of several different models, demonstrating that the observations are consistent with a smooth, broad, axisymmetric disk with inner radius 20-100 AU and width {approx}> 50 AU. The interferometric data require that at least half of the 860 {mu}m emission detected by previous single-dish observations with the James Clerk Maxwell Telescope be distributed axisymmetrically, ruling out strong contributions from flux concentrations on spatial scales of {approx}<100 AU. These observations support recent results from the Plateau de Bure Interferometer indicating that previous detections of clumpy structure in the Vega debris disk were spurious.

  9. Back injuries in a cohort of schoolchildren aged 6-12: A 2.5-year prospective study.

    PubMed

    Franz, C; Jespersen, E; Rexen, C T; Leboeuf-Yde, C; Wedderkopp, N

    2016-08-01

    The aims of this prospective school cohort study were to describe the epidemiology of diagnosed back pain in childhood, classified as either nontraumatic or traumatic back injury, and to estimate the association with physical activity in different settings. Over 2.5 years, 1240 children aged 6-12 years were surveyed weekly using mobile text messages to ask about the presence or absence of back pain. Pain was clinically diagnosed and injuries were classified using the International Classification of Diseases version 10. Physical activity data were obtained from text messages and accelerometers. Of the 315 back injuries diagnosed, 186 injuries were nontraumatic and 129 were traumatic. The incidence rate ratio was 1.5 for a nontraumatic back injury compared with a traumatic injury. The overall estimated back injury incidence rate was 0.20 per 1000 physical activity units (95% confidence interval 0.18-0.23). The back injury incidence rates were higher for sports when exposure per 1000 physical activity units was taken into consideration and especially children horse-riding had a 40 times higher risk of sustaining a traumatic back injury compared to the risk during non-organized leisure time physical activity. However, the reasonably low injury incidence rates support the recommendations of children continuously being physically active. PMID:26130046

  10. THE 0.5-2.22 {mu}m SCATTERED LIGHT SPECTRUM OF THE DISK AROUND TW Hya: DETECTION OF A PARTIALLY FILLED DISK GAP AT 80 AU

    SciTech Connect

    Debes, John H.; Jang-Condell, Hannah; Weinberger, Alycia J.; Roberge, Aki; Schneider, Glenn

    2013-07-01

    We present a 0.5-2.2 {mu}m scattered light spectrum of the circumstellar disk around TW Hya from a combination of spatially resolved Hubble Space Telescope STIS spectroscopy and NICMOS coronagraphic images of the disk. We investigate the morphology of the disk at distances >40 AU over this wide range of wavelengths, and identify the presence of a depression in surface brightness at {approx}80 AU that could be caused by a gap in the disk. Additionally, we quantify the surface brightness, azimuthal symmetry, and spectral character of the disk as a function of radius. Our analysis shows that the scattering efficiency of the dust is largely neutral to blue over the observed wavelengths. We model the disk as a steady {alpha}-disk with an ad hoc gap structure. The thermal properties of the disk are self-consistently calculated using a three-dimensional radiative transfer code that uses ray tracing to model the heating of the disk interior and scattered light images. We find a good fit to the data over a wide range of distances from the star if we use a model disk with a partially filled gap of 30% depth at 80 AU and with a self-similar truncation knee at 100 AU. The origin of the gap is unclear, but it could arise from a transition in the nature of the disk's dust composition or the presence of a planetary companion. Based on scalings to previous hydrodynamic simulations of gap-opening criteria for embedded proto-planets, we estimate that a planetary companion forming the gap could have a mass between 6 and 28 M{sub Circled-Plus }.

  11. A NEW 24 {mu}m PHASE CURVE FOR {upsilon} ANDROMEDAE b

    SciTech Connect

    Crossfield, Ian J. M.; Hansen, Brad M. S.; Harrington, Joseph; Cho, James Y.-K.; Deming, Drake; Seager, Sara E-mail: hansen@astro.ucla.ed E-mail: J.Cho@qmul.ac.u E-mail: kristen@astro.columbia.ed

    2010-11-10

    We report the detection of 24 {mu}m variations from the planet-hosting {upsilon} Andromedae system consistent with the orbital periodicity of the system's innermost planet, {upsilon} And b. We find a peak-to-valley phase curve amplitude of 0.00130 times the mean system flux. Using a simple model with two hemispheres of constant surface brightness and assuming a planetary radius of 1.3 R{sub J} give a planetary temperature contrast of {approx}>900 K and an orbital inclination of {approx}>28{sup 0}. We further report the largest phase offset yet observed for an extrasolar planet: the flux maximum occurs {approx}80{sup 0} before phase 0.5. Such a large phase offset is difficult to reconcile with most current atmospheric circulation models. We improve on earlier observations of this system in several important ways: (1) observations of a flux calibrator star demonstrate the MIPS detector is stable to 10{sup -4} on long timescales, (2) we note that the background light varies systematically due to spacecraft operations, precluding use of this background as a flux calibrator (stellar flux measured above the background is not similarly affected), and (3) we calibrate for flux variability correlated with motion of the star on the MIPS detector. A reanalysis of our earlier observations of this system is consistent with our new result.

  12. CONSTRAINING EXPLOSION TYPE OF YOUNG SUPERNOVA REMNANTS USING 24 {mu}m EMISSION MORPHOLOGY

    SciTech Connect

    Peters, Charee L.; Stassun, Keivan G.; Lopez, Laura A.; Figueroa-Feliciano, Enectali; Ramirez-Ruiz, Enrico

    2013-07-10

    Determination of the explosion type of supernova remnants (SNRs) can be challenging, as SNRs are hundreds to thousands of years old and supernovae are classified based on spectral properties days after explosion. Previous studies of thermal X-ray emission from Milky Way and Large Magellanic Cloud SNRs have shown that Type Ia and core-collapse (CC) SNRs have statistically different symmetries, and thus these sources can be typed based on their X-ray morphologies. In this Letter, we extend the same technique, a multipole expansion technique using power ratios, to infrared (IR) images of SNRs to test whether they can be typed using the symmetry of their warm dust emission as well. We analyzed archival Spitzer Space Telescope Multiband Imaging Photometer 24 {mu}m observations of the previously used X-ray sample, and we find that the two classes of SNRs separate according to their IR morphologies. The Type Ia SNRs are statistically more circular and mirror symmetric than the CC SNRs, likely due to the different circumstellar environments and explosion geometries of the progenitors. Broadly, our work indicates that the IR emission retains information of the explosive origins of the SNR and offers a new method to type SNRs based on IR morphology.

  13. THE LEGACY OF SCUPOL: 850 {mu}m IMAGING POLARIMETRY FROM 1997 TO 2005

    SciTech Connect

    Matthews, Brenda C.; McPhee, Christie A.; Fissel, Laura M.; Curran, Rachel L.

    2009-05-15

    SCUPOL, the polarimeter for SCUBA on the James Clerk Maxwell Telescope, was the most prolific thermal imaging polarimeter built to date. Between 1997 and 2005, observations of 104 regions were made at 850 {mu}m in the mapping mode. The instrument has produced {approx}50 refereed journal publications, and that number is still growing. We have systematically re-reduced all imaging polarimetry made in the standard 'jiggle-map' mode from the SCUBA archive (2800+ individual observations) to produce a catalog of SCUPOL images and tables. We present the results of our analysis with figures and data tables produced for all 83 regions where significant polarization was detected. In addition, the reduced data cubes and data tables can be accessed online. In many cases, the data included in this paper have been previously published elsewhere. However, this publication includes unpublished data sets, in whole or in part, toward 39 regions, including cores in {rho} Ophiuchus, Orion's OMC-2 region, several young stellar objects, and the galaxy M87.

  14. SWOC: Spectral Wavelength Optimization Code

    NASA Astrophysics Data System (ADS)

    Ruchti, G. R.

    2016-06-01

    SWOC (Spectral Wavelength Optimization Code) determines the wavelength ranges that provide the optimal amount of information to achieve the required science goals for a spectroscopic study. It computes a figure-of-merit for different spectral configurations using a user-defined list of spectral features, and, utilizing a set of flux-calibrated spectra, determines the spectral regions showing the largest differences among the spectra.

  15. A color sensor wavelength meter

    NASA Astrophysics Data System (ADS)

    Durfee, Dallin; Jackson, Jarom; Otterstrom, Nils; Jones, Tyler; Archibald, James

    2016-05-01

    We will discuss a laser wavelength meter based on a commercial color sensor chip consisting of an array of photodiodes with different absorptive color filters. By comparing the relative amplitudes of light on the photodiodes, the wavelength of light can be determined with picometer-level precision and with picometer-scale calibration drift over a period longer than a month. This work was supported by NSF Grant Number PHY-1205736.

  16. Towards short wavelengths FELs workshop

    SciTech Connect

    Ben-Zvi, I.; Winick, H.

    1993-12-01

    This workshop was caged because of the growing perception in the FEL source community that recent advances have made it possible to extend FEL operation to wavelengths about two orders of magnitude shorter than the 240 nm that has been achieved to date. In addition short wavelength FELs offer the possibilities of extremely high peak power (several gigawatts) and very short pulses (of the order of 100 fs). Several groups in the USA are developing plans for such short wavelength FEL facilities. However, reviewers of these plans have pointed out that it would be highly desirable to first carry out proof-of-principle experiments at longer wavelengths to increase confidence that the shorter wavelength devices will indeed perform as calculated. The need for such experiments has now been broadly accepted by the FEL community. Such experiments were the main focus of this workshop as described in the following objectives distributed to attendees: (1) Define measurements needed to gain confidence that short wavelength FELs will perform as calculated. (2) List possible hardware that could be used to carry out these measurements in the near term. (3) Define a prioritized FEL physics experimental program and suggested timetable. (4) Form collaborative teams to carry out this program.

  17. SPITZER 24 {mu}m EXCESSES FOR BRIGHT GALACTIC STARS IN BOOeTES AND FIRST LOOK SURVEY FIELDS

    SciTech Connect

    Hovhannisyan, L. R.; Mickaelian, A. M.; Weedman, D. W.; Houck, J. R.; Le Floc'h, E.; Soifer, B. T.; Brand, K.; Dey, A.; Jannuzi, B. T. E-mail: dweedman@isc.astro.cornell.edu

    2009-07-15

    Optically bright Galactic stars (V {approx}< 13 mag) having f {sub {nu}}(24 {mu}m) > 1 mJy are identified in Spitzer mid-infrared surveys within 8.2 deg{sup 2} for the Booetes field of the NOAO Deep Wide-Field Survey and within 5.5 deg{sup 2} for the First Look Survey (FLS). One hundred and twenty-eight stars are identified in Booetes and 140 in the FLS, and their photometry is given. (K - [24]) colors are determined using K magnitudes from the Two Micron All Sky Survey for all stars in order to search for excess 24 {mu}m luminosity compared to that arising from the stellar photosphere. Of the combined sample of 268 stars, 141 are of spectral types F, G, or K, and 17 of these 141 stars have 24 {mu}m excesses with (K - [24]) > 0.2 mag. Using limits on absolute magnitude derived from proper motions, at least eight of the FGK stars with excesses are main-sequence stars, and estimates derived from the distribution of apparent magnitudes indicate that all 17 are main-sequence stars. These estimates lead to the conclusion that between 9% and 17% of the main-sequence FGK field stars in these samples have 24 {mu}m infrared excesses. This result is statistically similar to the fraction of stars with debris disks found among previous Spitzer targeted observations of much brighter, main-sequence field stars.

  18. Fast stabilization of a CO{sub 2} laser for a frequency standard at 10 {mu}m

    SciTech Connect

    Pisani, M.Q.; Sassi, M.P.; Zucco, M.

    1994-12-31

    A CO{sub 2} laser has been frequency stabilized to an OsO{sub 4} transition with a control bandwidth of 10 kHz. The obtained spectral purity of the laser is 100 Hz. The realization of very accurate frequency standards and experiments of high resolution spectroscopy in the 10 {mu}m region are made possible by this source.

  19. Multiple myeloma oncogene 1 (MUM1)/interferon regulatory factor 4 (IRF4) upregulates monokine induced by interferon-gamma (MIG) gene expression in B-cell malignancy.

    PubMed

    Uranishi, M; Iida, S; Sanda, T; Ishida, T; Tajima, E; Ito, M; Komatsu, H; Inagaki, H; Ueda, R

    2005-08-01

    MUM1 (multiple myeloma oncogene 1)/IRF4 (interferon regulatory factor 4) is a transcription factor that is activated as a result of t(6;14)(p25;q32) in multiple myeloma. MUM1 expression is seen in various B-cell lymphomas and predicts an unfavorable outcome in some lymphoma subtypes. To elucidate its role in B-cell malignancies, we prepared MUM1-expressing Ba/F3 cells, which proliferated until higher cellular density than the parental cells, and performed cDNA microarray analysis to identify genes whose expression is regulated by MUM1. We found that the expression of four genes including FK506-binding protein 3 (FKBP3), the monokine induced by interferon-gamma(MIG), Fas apoptotic inhibitory molecule (Faim) and Zinc-finger protein 94 was altered in the MUM1-expressing cells. We then focused on MIG since its expression was immediately upregulated by MUM1. In reporter assays, MUM1 activated the MIG promoter in cooperation with PU.1, and the interaction between MUM1 and the MIG promoter sequence was confirmed. The expression of MIG was correlated with that of MUM1 in B-CLL cell lines, and treatment with neutralizing antibodies against MIG and its receptor, CXCR3, slightly inhibited the proliferation of two MUM1-expressing lines. These results suggest that MUM1 plays roles in the progression of B-cell lymphoma/leukemia by regulating the expression of various genes including MIG. Leukemia (2005) 19, 1471-1478. doi:10.1038/sj.leu.2403833; published online 16 June 2005.

  20. Sub-wavelength plasmon laser

    DOEpatents

    Bora, Mihail; Bond, Tiziana C.

    2016-04-19

    A plasmonic laser device has resonant nanocavities filled with a gain medium containing an organic dye. The resonant plasmon frequencies of the nanocavities are tuned to align with both the absorption and emission spectra of the dye. Variables in the system include the nature of the dye and the wavelength of its absorption and emission, the wavelength of the pumping radiation, and the resonance frequencies of the nanocavities. In addition the pumping frequency of the dye is selected to be close to the absorption maximum.

  1. Wavelength dependence of boron nitride ablation by TEA CO{sub 2} lasers

    SciTech Connect

    Sumiyoshi, T.; Tomita, H.; Takahashi, A.; Obara, M.; Ishii, K.

    1996-05-01

    Transversely excited atmospheric (TEA) CO{sub 2} laser ablation of boron nitride ceramics in both cubic and hexagonal phases (cBN, hBN) was demonstrated. A TEA CO{sub 2} laser oscillating at a wavelength of 9.2 {mu}m, which coincides with a TO-phonon spectrum of the cBN, could ablate the cBN ceramics more efficiently than with 10 {mu}m band radiation. The hBN samples were also ablated well with 9.2 {mu}m laser irradiation, however, the ablated site color changed to black due to a boron rich phase left on the surface. In the case of hBN sintered with Al{sub 2}O{sub 3} and SiO{sub 2}, the ablation threshold fluence is determined by the one of Al{sub 2}O{sub 3}, which is the highest threshold among the three elements. {copyright} {ital 1996 American Institute of Physics.}

  2. Wavelength shifting of intra-cavity photons: Adiabatic wavelength tuning in rapidly wavelength-swept lasers

    PubMed Central

    Jirauschek, Christian; Huber, Robert

    2015-01-01

    We analyze the physics behind the newest generation of rapidly wavelength tunable sources for optical coherence tomography (OCT), retaining a single longitudinal cavity mode during operation without repeated build up of lasing. In this context, we theoretically investigate the currently existing concepts of rapidly wavelength-swept lasers based on tuning of the cavity length or refractive index, leading to an altered optical path length inside the resonator. Specifically, we consider vertical-cavity surface-emitting lasers (VCSELs) with microelectromechanical system (MEMS) mirrors as well as Fourier domain mode-locked (FDML) and Vernier-tuned distributed Bragg reflector (VT-DBR) lasers. Based on heuristic arguments and exact analytical solutions of Maxwell’s equations for a fundamental laser resonator model, we show that adiabatic wavelength tuning is achieved, i.e., hopping between cavity modes associated with a repeated build up of lasing is avoided, and the photon number is conserved. As a consequence, no fundamental limit exists for the wavelength tuning speed, in principle enabling wide-range wavelength sweeps at arbitrary tuning speeds with narrow instantaneous linewidth. PMID:26203373

  3. On the nature of electroluminescence at 1.5 {mu}m in the breakdown mode of reverse-biased Er-doped silicon p-n-junction structures grown by sublimation molecular beam epitaxy

    SciTech Connect

    Kornaukhov, A. V. Ezhevskii, A. A.; Marychev, M. O.; Filatov, D. O.; Shengurov, V. G.

    2011-01-15

    Electroluminescence features in the wavelength range of 0.9-1.65 {mu}m were experimentally studied in the breakdown mode of reverse biased Si/Si:Er/Si p-n-junction structures grown by sublimation molecular-beam epitaxy. Based on the results of this study, a new physical model is proposed, in which radiative transitions in the near-infrared region are excited by recombination of electrons arriving at corresponding energy levels in the Si:Er layer due to their tunneling from the valence band of the p{sup +}-layer in the electric field of the reverse biased p-n-junction. The model proposed is in qualitative agreement with main available experimental results.

  4. 1.58 {mu}m InGaAs quantum well laser on GaAs

    SciTech Connect

    Taangring, I.; Ni, H. Q.; Wu, B. P.; Wu, D. H.; Xiong, Y. H.; Huang, S. S.; Niu, Z. C.; Wang, S. M.; Lai, Z. H.; Larsson, A.

    2007-11-26

    We demonstrate the 1.58 {mu}m emission at room temperature from a metamorphic In{sub 0.6}Ga{sub 0.4}As quantum well laser grown on GaAs by molecular beam epitaxy. The large lattice mismatch was accommodated through growth of a linearly graded buffer layer to create a high quality virtual In{sub 0.32}Ga{sub 0.68}As substrate. Careful growth optimization ensured good optical and structural qualities. For a 1250x50 {mu}m{sup 2} broad area laser, a minimum threshold current density of 490 A/cm{sup 2} was achieved under pulsed operation. This result indicates that metamorphic InGaAs quantum wells can be an alternative approach for 1.55 {mu}m GaAs-based lasers.

  5. HIGH-RESOLUTION 1.6 {mu}m SPECTRA OF FeH IN M AND L DWARFS {sup ,}

    SciTech Connect

    Hargreaves, Robert J.; Bernath, Peter F.; Hinkle, Kenneth H.; Bauschlicher, Charles W.; Wende, Sebastian; Seifahrt, Andreas E-mail: pfb500@york.ac.u E-mail: Charles.W.Bauschlicher@nasa.go E-mail: seifahrt@physics.ucdavis.ed

    2010-10-15

    Near-infrared bands due to the iron monohydride (FeH) molecule are a characteristic feature of late-M and -L dwarfs. We have created a line list at 2200 K for the FeH E {sup 4{Pi}}-A {sup 4{Pi}} electronic transition near 1.58 {mu}m (6300 cm{sup -1}) based on laboratory spectra and an ab initio calculation of the band strength. A variety of M and L dwarfs were observed near 1.6 {mu}m with high spectral resolution (R {approx} 70,000) using the Phoenix spectrograph on the 8.1 m Gemini South telescope. The FeH E-A transition made a surprisingly strong contribution to the observed spectral energy distributions and needs to be included in modeling of late-M and L dwarfs.

  6. TESTING 24 {mu}m AND INFRARED LUMINOSITY AS STAR FORMATION TRACERS FOR GALACTIC STAR-FORMING REGIONS

    SciTech Connect

    Vutisalchavakul, Nalin; Evans, Neal J. II

    2013-03-10

    We have tested some relations for star formation rates used in extragalactic studies for regions within the Galaxy. In nearby molecular clouds, where the initial mass function is not fully sampled, the dust emission at 24 {mu}m greatly underestimates star formation rates (by a factor of 100 on average) when compared to star formation rates determined from counting young stellar objects. The total infrared emission does no better. In contrast, the total far-infrared method agrees within a factor of two on average with star formation rates based on radio continuum emission for massive, dense clumps that are forming enough massive stars to have L{sub TIR} exceed 10{sup 4.5} L{sub Sun }. The total infrared and 24 {mu}m also agree well with each other for both nearby, low-mass star-forming regions and the massive, dense clump regions.

  7. Wavelength-modulated photocapacitance spectroscopy

    NASA Technical Reports Server (NTRS)

    Kamieniecki, E.; Lagowski, J.; Gatos, H. C.

    1980-01-01

    Derivative deep-level spectroscopy was achieved with wavelength-modulated photocapacitance employing MOS structures and Schottky barriers. The energy position and photoionization characteristics of deep levels of melt-grown GaAs and the Cr level in high-resistivity GaAs were determined. The advantages of this method over existing methods for deep-level spectroscopy are discussed.

  8. Solid colloidal optical wavelength filter

    DOEpatents

    Alvarez, Joseph L.

    1992-01-01

    A solid colloidal optical wavelength filter includes a suspension of spheal particles dispersed in a coagulable medium such as a setting plastic. The filter is formed by suspending spherical particles in a coagulable medium; agitating the particles and coagulable medium to produce an emulsion of particles suspended in the coagulable medium; and allowing the coagulable medium and suspended emulsion of particles to cool.

  9. Wavelength-shifted Cherenkov radiators

    NASA Technical Reports Server (NTRS)

    Krider, E. P.; Jacobson, V. L.; Pifer, A. E.; Polakos, P. A.; Kurz, R. J.

    1976-01-01

    The scintillation and Cherenkov responses of plastic Cherenkov radiators containing different wavelength-shifting fluors in varying concentrations have been studied in beams of low energy protons and pions. For cosmic ray applications, where large Cherenkov to scintillation ratios are desired, the optimum fluor concentrations are 0.000025 by weight or less.

  10. F, G, K, M SPECTRAL STANDARDS IN THE Y BAND (0.95-1.11 {mu}m)

    SciTech Connect

    Sharon, Chelsea; Hillenbrand, Lynne; Fischer, William; Edwards, Suzan E-mail: lah@astro.caltech.edu E-mail: sedwards@ast.smith.edu

    2010-02-15

    We take advantage of good atmospheric transparency and the availability of high-quality instrumentation in the 1 {mu}m near-infrared atmospheric window to present a grid of F, G, K, and M spectral standards observed at high spectral resolution (R {approx} 25, 000). In addition to a spectral atlas, we present a catalog of atomic line absorption features in the 0.95-1.11 {mu}m range. The catalog includes a wide range of line excitation potentials, from 0-13 eV, arising from neutral and singly ionized species, most frequently those of Fe I and Ti I at low excitation, Cr I, Fe I, and Si I at moderate excitation, and C I, S I, and Si I having relatively high excitation. The spectra also include several prominent molecular bands from CN and FeH. For the atomic species, we analyze trends in the excitation potential, line depth, and equivalent width across the grid of spectroscopic standards to identify temperature and surface gravity diagnostics near 1 {mu}m. We identify the line ratios that appear especially useful for spectral typing as those involving Ti I and C I or S I, which are temperature sensitive in opposite directions, and Sr II, which is gravity sensitive at all spectral types. ASCII versions of all spectra are available in the online version of the journal.

  11. Teacher's Guide to Resources of the Oklahoma Historical Society, Keyed to the Priority Academic Student Skills (PASS), Grades 6-12 Oklahoma History.

    ERIC Educational Resources Information Center

    National Diffusion Network (DHEW/OE), Washington, DC.

    This guide is correlated to the PASS (Priority Academic Student Skills) objectives for Oklahoma history in grades 6-12. The guide was developed to aid in the teaching of the PASS objectives by identifying primary sources, audiovisual materials, field trips and scholarly materials that relate to each objective. The guide is divided into seven…

  12. Validity and Reliability Study of the Self-Efficacy Scale in Rendering Piano Education to Children of 6-12 Years

    ERIC Educational Resources Information Center

    Ekinci, Hatice

    2014-01-01

    This study was conducted in order to develop a valid and reliable scale that can be used in measuring self-efficacy of candidate music teachers in rendering piano education to children of 6-12 years. To this end, a pool of 51 items was created by using the literature, and taking the opinions of piano professors and piano instructors working with…

  13. Absorptivity modulation on wavy molten steel surfaces: The influence of laser wavelength and angle of incidence

    SciTech Connect

    Kaplan, A. F. H.

    2012-10-08

    The modulation of the angle-dependent Fresnel absorptivity across wavy molten steel surfaces during laser materials processing, like drilling, cutting, or welding, has been calculated. The absorptivity is strongly altered by the grazing angle of incidence of the laser beam on the processing front. Owing to its specific Brewster-peak characteristics, the 10.64 {mu}m wavelength CO{sub 2}-laser shows an opposite trend with respect to roughness and angle-of-incidence compared to lasers in the wavelength range of 532-1070 nm. Plateaus or rings of Brewster-peak absorptivity can lead to hot spots on a wavy surface, often in close proximity to cold spots caused by shadow domains.

  14. INFRARED LUMINOSITIES AND AROMATIC FEATURES IN THE 24 {mu}m FLUX-LIMITED SAMPLE OF 5MUSES

    SciTech Connect

    Wu Yanling; Helou, George; Shi Yong E-mail: gxh@ipac.caltech.ed

    2010-11-01

    We study a 24 {mu}m selected sample of 330 galaxies observed with the infrared spectrograph for the 5 mJy Unbiased Spitzer Extragalactic Survey. We estimate accurate total infrared luminosities by combining mid-IR spectroscopy and mid-to-far infrared photometry, and by utilizing new empirical spectral templates from Spitzer data. The infrared luminosities of this sample range mostly from 10{sup 9} L{sub sun} to 10{sup 13.5} L{sub sun}, with 83% in the range 10{sup 10} L{sub sun} < L{sub IR} < 10{sup 12} L{sub sun}. The redshifts range from 0.008 to 4.27, with a median of 0.144. The equivalent widths of the 6.2 {mu}m aromatic feature have a bimodal distribution, probably related to selection effects. We use the 6.2 {mu}m polycyclic aromatic hydrocarbon equivalent width (PAH EW) to classify our objects as starburst (SB)-dominated (44%), SB-AGN composite (22%), and active galactic nucleus (AGN)-dominated (34%). The high EW objects (SB-dominated) tend to have steeper mid-IR to far-IR spectral slopes and lower L{sub IR} and redshifts. The low EW objects (AGN-dominated) tend to have less steep spectral slopes and higher L{sub IR} and redshifts. This dichotomy leads to a gross correlation between EW and slope, which does not hold within either group. AGN-dominated sources tend to have lower log(L{sub PAH7.7{sub {mu}m}}/L{sub PAH11.3{sub {mu}m}}) ratios than star-forming galaxies, possibly due to preferential destruction of the smaller aromatics by the AGN. The log(L{sub PAH7.7{sub {mu}m}}/L{sub PAH11.3{sub {mu}m}}) ratios for star-forming galaxies are lower in our sample than the ratios measured from the nuclear spectra of nearby normal galaxies, most probably indicating a difference in the ionization state or grain size distribution between the nuclear regions and the entire galaxy. Finally, we provide a calibration relating the monochromatic continuum or aromatic feature luminosity to L{sub IR} for different types of objects.

  15. Review of short wavelength lasers

    SciTech Connect

    Hagelstein, P.L.

    1985-03-18

    There has recently been a substantial amount of research devoted to the development of short wavelength amplifiers and lasers. A number of experimental results have been published wherein the observation of significant gain has been claimed on transitions in the EUV and soft x-ray regimes. The present review is intended to discuss the main approaches to the creation of population inversions and laser media in the short wavelength regime, and hopefully aid workers in the field by helping to provide access to a growing literature. The approaches to pumping EUV and soft x-ray lasers are discussed according to inversion mechanism. The approaches may be divided into roughly seven categories, including collisional excitation pumping, recombination pumping, direct photoionization and photoexcitation pumping, metastable state storage plus optical pumping, charge exchange pumping, and finally, the extension of free electron laser techniques into the EUV and soft x-ray regimes. 250 references.

  16. Wavelength dependence of ocular damage thresholds in the near-ir to far-ir transition region: proposed revisions to MPES.

    PubMed

    Zuclich, Joseph A; Lund, David J; Stuck, Bruce E

    2007-01-01

    This report summarizes the results of a series of infrared (IR) laser-induced ocular damage studies conducted over the past decade. The studies examined retinal, lens, and corneal effects of laser exposures in the near-IR to far-IR transition region (wavelengths from 1.3-1.4 mum with exposure durations ranging from Q-switched to continuous wave). The corneal and retinal damage thresholds are tabulated for all pulsewidth regimes, and the wavelength dependence of the IR thresholds is discussed and contrasted to laser safety standard maximum permissible exposure limits. The analysis suggests that the current maximum permissible exposure limits could be beneficially revised to (1) relax the IR limits over wavelength ranges where unusually high safety margins may unintentionally hinder applications of recently developed military and telecommunications laser systems; (2) replace step-function discontinuities in the IR limits by continuously varying analytical functions of wavelength and pulsewidth which more closely follow the trends of the experimental retinal (for point-source laser exposures) and corneal ED50 threshold data; and (3) result in an overall simplification of the permissible exposure limits over the wavelength range from 1.2-2.6 mum. A specific proposal for amending the IR maximum permissible exposure limits over this wavelength range is presented.

  17. Laser wavelengths and oral implantology.

    PubMed

    Romanos, George E; Gutknecht, Norbert; Dieter, Sandra; Schwarz, Frank; Crespi, Roberto; Sculean, Anton

    2009-11-01

    In modern implant dentistry there are several clinical indications for laser surgery. Different laser systems have a considerable spectrum of application in soft and hard peri-implant tissues. The literature was searched for clinical application of different laser wavelengths in peri-implant tissues: second-stage surgery of submerged implants, treatment of infrabony defects, removal of peri-implant hyperplastic overgrowths, and, possibly, the preparation of bone cavities for implant placement. This report describes the state-of-the-art application of different laser systems in modern implant dentistry for the treatment of peri-implant lesions and decontamination of implant surfaces. Our study evaluated in vitro examinations, clinical experience and long-term clinical studies. The exact selection of the appropriate laser system and wavelength was dependent on the scientific evaluation of recent literature and the level of changes in implant and tissue temperatures during laser application. The significant reduction in bacteria on the implant surface and the peri-implant tissues during irradiation and the cutting effects associated with the coagulation properties of the lasers are the main reasons for laser application in the treatment of peri-implant lesions and the successful long-term prognosis of failing oral implants. The various applications of lasers in implant dentistry are dependent on the wavelength and laser-tissue interactions.

  18. The Arabidopsis MUM2 Gene Encodes a β-Galactosidase Required for the Production of Seed Coat Mucilage with Correct Hydration Properties[W

    PubMed Central

    Dean, Gillian H.; Zheng, Huanquan; Tewari, Jagdish; Huang, Jun; Young, Diana S.; Hwang, Yeen Ting; Western, Tamara L.; Carpita, Nicholas C.; McCann, Maureen C.; Mansfield, Shawn D.; Haughn, George W.

    2007-01-01

    Seed coat development in Arabidopsis thaliana involves a complex pathway where cells of the outer integument differentiate into a highly specialized cell type after fertilization. One aspect of this developmental process involves the secretion of a large amount of pectinaceous mucilage into the apoplast. When the mature seed coat is exposed to water, this mucilage expands to break the primary cell wall and encapsulate the seed. The mucilage-modified2 (mum2) mutant is characterized by a failure to extrude mucilage on hydration, although mucilage is produced as normal during development. The defect in mum2 appears to reside in the mucilage itself, as mucilage fails to expand even when the barrier of the primary cell wall is removed. We have cloned the MUM2 gene and expressed recombinant MUM2 protein, which has β-galactosidase activity. Biochemical analysis of the mum2 mucilage reveals alterations in pectins that are consistent with a defect in β-galactosidase activity, and we have demonstrated that MUM2 is localized to the cell wall. We propose that MUM2 is involved in modifying mucilage to allow it to expand upon hydration, establishing a link between the galactosyl side-chain structure of pectin and its physical properties. PMID:18165329

  19. Note: Laser wavelength precision measurement based on a laser synthetic wavelength interferometer

    NASA Astrophysics Data System (ADS)

    Yan, Liping; Chen, Benyong; Zhang, Shihua; Liu, Pengpeng; Zhang, Enzheng

    2016-08-01

    A laser wavelength precision measurement method is presented based on the laser synthetic wavelength interferometer (LSWI). According to the linear relation between the displacements of measurement and reference arms in the interferometer, the synthetic wavelength produced by an unknown wavelength and a reference wavelength can be measured by detecting the phase coincidences of two interference signals. The advantage of the method is that a larger synthetic wavelength resulting from an unknown wavelength very close to the reference wavelength can be easily determined according to the linear relation in the interferometer. Then the unknown wavelength is derived according to the one-to-one corresponding relationship between single wavelength and synthetic wavelength. Wavelengths of an external cavity diode laser and two He-Ne lasers were determined experimentally. The experimental results show that the proposed method is able to realize a relative uncertainty on the order of 10-8.

  20. Note: Laser wavelength precision measurement based on a laser synthetic wavelength interferometer.

    PubMed

    Yan, Liping; Chen, Benyong; Zhang, Shihua; Liu, Pengpeng; Zhang, Enzheng

    2016-08-01

    A laser wavelength precision measurement method is presented based on the laser synthetic wavelength interferometer (LSWI). According to the linear relation between the displacements of measurement and reference arms in the interferometer, the synthetic wavelength produced by an unknown wavelength and a reference wavelength can be measured by detecting the phase coincidences of two interference signals. The advantage of the method is that a larger synthetic wavelength resulting from an unknown wavelength very close to the reference wavelength can be easily determined according to the linear relation in the interferometer. Then the unknown wavelength is derived according to the one-to-one corresponding relationship between single wavelength and synthetic wavelength. Wavelengths of an external cavity diode laser and two He-Ne lasers were determined experimentally. The experimental results show that the proposed method is able to realize a relative uncertainty on the order of 10(-8). PMID:27587172

  1. Vertical cavity surface emitting lasers emitting near 1.5 {mu}m with Sb-based reflectors

    SciTech Connect

    Blum, O.; Klem, J.F.; Vawter, G.A.

    1998-04-01

    We describe use of AlAsSb/AlGaAsSb lattice matched to InP for distributed Bragg reflectors. These structures are integral to several surface normal devices, in particular vertical cavity surface emitting lasers. The high refractive index ratio of these materials allows formation of a highly reflective mirror with relatively few mirror pairs. As a result, we have been able to show for the first time the 77K CW operation of an optically pumped, monolithic, all-epitaxial vertical cavity laser, emitting at 1.56 {mu}m.

  2. InAs/InP single quantum wire formation and emission at 1.5 {mu}m

    SciTech Connect

    Alen, B.; Fuster, D.; Gonzalez, Y.; Gonzalez, L.; Martinez-Pastor, J.

    2006-12-04

    Isolated InAs/InP self-assembled quantum wires have been grown using in situ accumulated stress measurements to adjust the optimal InAs thickness. Atomic force microscopy imaging shows highly asymmetric nanostructures with average length exceeding more than ten times their width. High resolution optical investigation of as-grown samples reveals strong photoluminescence from individual quantum wires at 1.5 {mu}m. Additional sharp features are related to monolayer fluctuations of the two-dimensional InAs layer present during the early stages of the quantum wire self-assembling process.

  3. Quantitative chemical identification of four gases in remote infrared (9-11 mum) differential absorption lidar experiments.

    PubMed

    Quagliano, J R; Stoutland, P O; Petrin, R R; Sander, R K; Romero, R J; Whitehead, M C; Quick, C R; Tiee, J J; Jolin, L J

    1997-03-20

    A combined experimental and computational approach utilizing tunable CO(2) lasers and chemometric analysis was employed to detect chemicals and their concentrations in the field under controlled release conditions. We collected absorption spectra for four organic gases in the laboratory by lasing 40 lines of the laser in the 9.3-10.8-mum range. The ability to predict properly the chemicals and their respective concentrations depends on the nature of the target, the atmospheric conditions, and the round-trip distance. In 39 of the 45 field experiments, the identities of the released chemicals were identified correctly without predictions of false positives or false negatives. PMID:18250883

  4. Wavelength tunable alexandrite regenerative amplifier

    SciTech Connect

    Harter, D.J.; Bado, P.

    1988-11-01

    We describe a wavelength tunable alexandrite regenerative amplifier which is used to amplify nanosecond slices from a single-frequency cw dye laser or 50-ps pulses emitted by a diode laser to energies in the 10-mJ range. The amplified 5-ns slices generated by the cw-pumped line narrowed dye laser are Fourier transform limited. The 50-ps pulses emitted by a gain-switched diode laser are amplified by more than 10 orders of magnitude in a single stage.

  5. Plasmonic lens for ultraviolet wavelength

    NASA Astrophysics Data System (ADS)

    Takeda, Minoru; Tanimoto, Takuya; Inoue, Tsutomu; Aizawa, Kento

    2016-09-01

    A plasmonic lens (PL) is one of the promising photonic devices utilizing the surface plasmon wave. In this study, we have newly developed a PL with a 3.5 µm diameter for a wavelength of 375 nm (ultraviolet region). It is composed of multiple circular slit apertures milled in aluminum (Al) thin film. We have simulated the electric field distribution of the PL, and confirmed that a tightly focused beam spot of subwavelength size in the far-field region was attained. We have also measured the focusing characteristics of the PL using a near-field scanning optical microscope (NSOM) and compared them with the calculated results.

  6. Set the P.A.C.E.! A Curriculum to Promote Mother-Child Communication about Sexuality and Reduce Sexual Risk Behaviors in Children Ages 6-12

    ERIC Educational Resources Information Center

    DiIorio, Colleen K.; Pluhar, Erika I.; Pines, Kathy; Jennings, Tanya

    2006-01-01

    In this article, we describe the Set the P.A.C.E.! (Parents And Children Empowered) curriculum designed for mothers of children 6-12 years of age. The development of the curriculum was part of a research study to test an intervention to enhance the mother's role in promoting resilience among 6- to 12-year-old children and to reduce the risk of…

  7. The Effect of Recorded Mum's Lullaby and Brahm’s Lullaby on Oxygen Saturation in Preterm Infants: a Randomized Double-Blind Clinical Trial

    PubMed Central

    Jabraeili, Mahnaz; Sabet, Tahmineh; MustafaGharebaghi, Manijeh; Asghari Jafarabadi, Mohammad; Arshadi, Mohammad

    2016-01-01

    Introduction: Music stimulation has been shown to provide significant benefits to preterm infants. Thus the aim of this study was determine the effect of recorded mum's lullaby and Brahm’s lullaby on oxygen saturation in preterm infants. Methods: This double-blind randomized controlled trial was carried out on 66 premature newborns with the postnatal age of ≥3 days and weight ≤ 2800 grams at Taleghani Hospital. Infants were randomly divided into three groups: control, Brahm’s lullaby and Mum's lullaby groups. Infants were continuously monitored for primary outcome of percutaneous oxygen saturation, for three consecutive sessions. Results: There were significant difference in neonate oxygen saturation between the Brahm’s lullaby and Mum's lullaby as compared with control groups in the 15 minutes after intervention. Conclusion: This study showed beneficial effects of Brahm’s lullaby and Mum's lullaby sound. Therefore; it may be used for improving short term outcomes in premature infants. PMID:26989669

  8. Compact silicon photonic wavelength-tunable laser diode with ultra-wide wavelength tuning range

    SciTech Connect

    Kita, Tomohiro Tang, Rui; Yamada, Hirohito

    2015-03-16

    We present a wavelength-tunable laser diode with a 99-nm-wide wavelength tuning range. It has a compact wavelength-tunable filter with high wavelength selectivity fabricated using silicon photonics technology. The silicon photonic wavelength-tunable filter with wide wavelength tuning range was realized using two ring resonators and an asymmetric Mach-Zehnder interferometer. The wavelength-tunable laser diode fabricated by butt-joining a silicon photonic filter and semiconductor optical amplifier shows stable single-mode operation over a wide wavelength range.

  9. Compact silicon photonic wavelength-tunable laser diode with ultra-wide wavelength tuning range

    NASA Astrophysics Data System (ADS)

    Kita, Tomohiro; Tang, Rui; Yamada, Hirohito

    2015-03-01

    We present a wavelength-tunable laser diode with a 99-nm-wide wavelength tuning range. It has a compact wavelength-tunable filter with high wavelength selectivity fabricated using silicon photonics technology. The silicon photonic wavelength-tunable filter with wide wavelength tuning range was realized using two ring resonators and an asymmetric Mach-Zehnder interferometer. The wavelength-tunable laser diode fabricated by butt-joining a silicon photonic filter and semiconductor optical amplifier shows stable single-mode operation over a wide wavelength range.

  10. Multi-wavelength fluorescence tomography

    NASA Astrophysics Data System (ADS)

    Kwong, Tiffany C.; Lo, Pei-An; Cho, Jaedu; Nouizi, Farouk; Chiang, Huihua K.; Kim, Chang-Seok; Gulsen, Gultekin

    2016-03-01

    The strong scattering and absorption of light in biological tissue makes it challenging to model the propagation of light, especially in deep tissue. This is especially true in fluorescent tomography, which aims to recover the internal fluorescence source distribution from the measured light intensities on the surface of the tissue. The inherently ill-posed and underdetermined nature of the inverse problem along with strong tissue scattering makes Fluorescence Tomography (FT) extremely challenging. Previously, multispectral detection fluorescent tomography (FT) has been shown to improve the image quality of FT by incorporating the spectral filtering of biological tissue to provide depth information to overcome the inherent absorption and scattering limitations. We investigate whether multi-wavelength fluorescent tomography can be used to distinguish the signals from multiple fluorophores with overlapping fluorescence spectrums using a unique near-infrared (NIR) swept laser. In this work, a small feasibility study was performed to see whether multi-wavelength FT can be used to detect subtle shifts in the absorption spectrum due to differences in fluorophore microenvironment.

  11. Making Displaced Holograms At Two Wavelengths

    NASA Technical Reports Server (NTRS)

    Witherow, William K.; Ecker, Andreas

    1989-01-01

    Two-wavelength holographic system augmented with pair of prisms to introduce small separation between holograms formed simultaneously at two wavelengths on holographic plate. Principal use in study of flows. Gradients in index of refraction of fluid caused by variations in temperature, concentration, or both. Holography at one wavelength cannot be used to distinguish between two types of variations. Difference between spacings of fringes in photographs reconstructed from holograms taken simultaneously at two different wavelengths manipulated mathematically to determine type of variation.

  12. The cost-effectiveness of the MobileMums intervention to increase physical activity among mothers with young children: a Markov model informed by a randomised controlled trial

    PubMed Central

    Burn, Edward; Barnett, Adrian G; Fjeldsoe, Brianna S; Graves, Nicholas

    2015-01-01

    Objectives To determine the cost-effectiveness of the MobileMums intervention. MobileMums is a 12-week programme which assists mothers with young children to be more physically active, primarily through the use of personalised SMS text-messages. Design A cost-effectiveness analysis using a Markov model to estimate and compare the costs and consequences of MobileMums and usual care. Setting This study considers the cost-effectiveness of MobileMums in Queensland, Australia. Participants A hypothetical cohort of over 36 000 women with a child under 1 year old is considered. These women are expected to be eligible and willing to participate in the intervention in Queensland, Australia. Data sources The model was informed by the effectiveness results from a 9-month two-arm community-based randomised controlled trial undertaken in 2011 and registered retrospectively with the Australian Clinical Trials Registry (ACTRN12611000481976). Baseline characteristics for the model cohort, treatment effects and resource utilisation were all informed by this trial. Main outcome measures The incremental cost per quality-adjusted life year (QALY) of MobileMums compared with usual care. Results The intervention is estimated to lead to an increase of 131 QALYs for an additional cost to the health system of 1.1 million Australian dollars (AUD). The expected incremental cost-effectiveness ratio for MobileMums is 8608 AUD per QALY gained. MobileMums has a 98% probability of being cost-effective at a cost-effectiveness threshold of 64 000 AUD. Varying modelling assumptions has little effect on this result. Conclusions At a cost-effectiveness threshold of 64 000 AUD, MobileMums would likely be a cost-effective use of healthcare resources in Queensland, Australia. Trial registration number Australian Clinical Trials Registry; ACTRN12611000481976. PMID:25926145

  13. Multiple wavelength light collimator and monitor

    NASA Technical Reports Server (NTRS)

    Gore, Warren J. (Inventor)

    2011-01-01

    An optical system for receiving and collimating light and for transporting and processing light received in each of N wavelength ranges, including near-ultraviolet, visible, near-infrared and mid-infrared wavelengths, to determine a fraction of light received, and associated dark current, in each wavelength range in each of a sequence of time intervals.

  14. Focusing X-rays to a 1-{mu}m spot using elastically bent, graded multilayer coated mirrors

    SciTech Connect

    Underwood, J.H.; Thompson, A.C.; Kortright, J.B.

    1997-04-01

    In the x-ray fluorescent microprobe at beamline 10.3.1, the ALS bending magnet source is demagnified by a factor of several hundred using a pair of mirrors arranged in the Kirkpatrick-Baez (K-B) configuration. These are coated with multilayers to increase reflectivity and limit the pass band of the x-rays striking the sample. The x-rays excite characteristic fluorescent x-rays of elements in the sample, which are analyzed by an energy dispersive Si-Li detector, for a sensitive assay of the elemental content. By scanning the focal spot the spatial distribution of the elements is determined; the spatial resolution depends on the size of this spot. When spherical mirrors are used, the spatial resolution is limited by aberrations to 5 or 10 {mu}m. This has been improved to 1 {mu}m through the use of an elliptical mirror formed by elastically bending a plane mirror of uniform width and thickness with the optimum combination of end couples.

  15. 1.55 {mu}m GaInNAs resonant-cavity-enhanced photodetector grown on GaAs

    SciTech Connect

    Han, Q.; Yang, X.H.; Niu, Z.C.; Ni, H.Q.; Xu, Y.Q.; Zhang, S.Y.; Du, Y.; Peng, L.H.; Zhao, H.; Tong, C.Z.; Wu, R.H.; Wang, Q.M.

    2005-09-12

    We report the design, growth, fabrication, and characterization of a GaAs-based resonant-cavity-enhanced (RCE) GaInNAs photodetector operating at 1.55 {mu}m. The structure of the device was designed using a transfer-matrix method (TMM). By optimizing the molecular-beam epitaxy growth conditions, six GaInNAs quantum wells were used as the absorption layers. Twenty-five (25)- and 9-pair GaAs/AlAs-distributed Bragg reflectors were grown as the bottom and top mirrors. At 1.55 {mu}m, a quantum efficiency of 33% with a full width at half maximum of 10 nm was obtained. The dark current density was 3x10{sup -7} A/cm{sup 2} at a bias of 0 V and 4.3x10{sup -5} A/cm{sup 2} at a reverse bias of 5 V. The primary time response measurement shows that the device has a rise time of less than 800 ps.

  16. Development of a PM-10 inlet for continuous operation and with recovery of the {gt}10-{mu}m fraction

    SciTech Connect

    Langer, G.; Pauley, B.J.

    1992-09-01

    The Rocky Flats Plant (RFP) manufactured nuclear weapons` components out of plutonium (Pu) metal until 1990. The plant is now in a decontamination and disposition phase. In both the manufacturing mode and the present mode, Department of Energy (DOE), Environmental Protection Agency (EPA) and the State of Colorado have required continuous monitoring of the air to detect releases of radionuclides. The air surveillance network established around the plant in the early 1950`s was replaced in 1972 with a network of high-volume (40 cfm) samplers (hivols). This network extends into the community. The hivois were patterned after the EPA total suspended particle (TSP) samplers with an approximate cutoff at 30 micrometers ({mu}m); however, the RFP version of the TSP sampler was designed to operate continuously and had to be relatively inconspicuous. After nearly 20 years of operation, the RFP air surveillance samplers are in need of updating or replacement, in part because the EPA has now established a new criterion for sampling of suspended particles; i.e., the PM-10 criterion. Only particles of less than 10-{mu}m aerodynamic diameter are considered hazardous to health through inhalation pathways. This report discusses the development of a PM-10 inlet for continuous operation.

  17. CW lasing in Yb{sup 3+} : GGG crystals pumped at 0.925 {mu}m

    SciTech Connect

    Belovolov, A M; Belovolov, M I; Dianov, Evgenii M; Dudin, V V; Timoshechkin, M I E-mail: dianov@fo.gpi.r

    2006-07-31

    Single-mode cw lasing was obtained for the first time in Yb{sup 3+} : GGG crystals at room temperature at 1.030 and 1.037 {mu}m upon pumping Yb{sup 3+} ions by a 0.925-{mu}m neodymium-doped fibre laser. Lasing was observed at the transitions between the lower Stark sublevel of the {sup 2}F{sub 5/2} level and the upper Stark sublevels of the {sup 2}F{sub 7/2} ground state of Yb{sup 3+} ions. The study of lasing characteristic showed that lasing occurs according to the four-level scheme. The lasing threshold with respect to the absorbed power was 85 mW and the slope lasing efficiency was 20%. Upon 1.7-W pumping, the output power of 310 mW was achieved with the output resonator mirror with the transmission coefficient of 1%. The effective cross section of the lasing transition was 0.9x10{sup -20} cm{sup 2}. (special issue devoted to the 90th anniversary of a.m. prokhorov)

  18. Sub-microsecond wavelength stabilization of tunable lasers with the internal wavelength locker

    NASA Astrophysics Data System (ADS)

    Kimura, Ryoga; Tatsumoto, Yudai; Sakuma, Kazuki; Onji, Hirokazu; Shimokozono, Makoto; Ishii, Hiroyuki; Kato, Kazutoshi

    2016-08-01

    We proposed a method of accelerating the wavelength stabilization after wavelength switching of the tunable distributed amplification-distributed feedback (TDA-DFB) laser using the internal wavelength locker to reduce the size and the cost of the wavelength control system. The configuration of the wavelength stabilization system based on this locker was as follows. At the wavelength locker, the light intensity after an optical filter is detected as a current by the photodiodes (PDs). Then, for estimating the wavelength, the current is processed by the current/voltage-converting circuit (IVC), logarithm amplifier (Log Amp) and field programmable gate array (FPGA). Finally, the laser current is tuned to the desired wavelength with reference to the estimated wavelength. With this control system the wavelength is stabilized within 800 ns after wavelength switching, which is even faster than that with the conventional control system.

  19. Internet Cognitive Behavioral Therapy for Women With Postnatal Depression: A Randomized Controlled Trial of MumMoodBooster

    PubMed Central

    Milgrom, Jeannette; Danaher, Brian G; Holt, Charlene; Holt, Christopher J; Seeley, John R; Tyler, Milagra S; Ross, Jessica; Ericksen, Jennifer

    2016-01-01

    Background There are few published controlled trials examining the efficacy of Internet-based treatment for postnatal depression (PND) and none that assess diagnostic status (clinical remission) as the primary outcome. This is despite the need to improve treatment uptake and accessibility because fewer than 50% of postnatally depressed women seek help, even when identified as depressed. Objective In a randomized controlled trial (RCT), we aimed to test the efficacy of a 6-session Internet intervention (the MumMoodBooster program, previously evaluated in a feasibility trial) in a sample of postnatal women with a clinical diagnosis of depression. The MumMoodBooster program is a cognitive behavioral therapy (CBT) intervention, is highly interactive, includes a partner website, and was supported by low-intensity telephone coaching. Methods This was a parallel 2-group RCT (N=43) comparing the Internet CBT treatment (n=21) to treatment as usual (n=22). At baseline and at 12 weeks after enrollment, women’s diagnostic status was assessed by telephone with the Standardized Clinical Interview for DSM-IV (SCID-IV) and symptom severity with the Beck Depression Inventory (BDI-II). Depression symptoms were measured repeatedly throughout the study period with the Patient Health Questionnaire (PHQ-9). Results At the end of the study, 79% (15/19) of women who received the Internet CBT treatment no longer met diagnostic criteria for depression on the SCID-IV (these outcome data were missing for 2 intervention participants). This contrasted with only 18% (4/22) remission in the treatment as usual condition. Depression scores on the BDI-II showed a large effect favoring the intervention group (d=.83, 95% CI 0.20-1.45). Small to medium effects were found on the PHQ-9 and on measures of anxiety and stress. Adherence to the program was very good with 86% (18/21) of users completing all sessions; satisfaction with the program was rated 3.1 out of 4 on average. Conclusions Our results

  20. Retinal spot size with wavelength

    NASA Astrophysics Data System (ADS)

    Rockwell, Benjamin A.; Hammer, Daniel X.; Kennedy, Paul K.; Amnotte, Rodney E.; Eilert, Brent; Druessel, Jeffrey J.; Payne, Dale J.; Phillips, Shana L.; Stolarski, David J.; Noojin, Gary D.; Thomas, Robert J.; Cain, Clarence P.

    1997-06-01

    We have made an indirect in-vivo determination of spot size focusing in the rhesus monkey model. Measurement of the laser induced breakdown threshold both in-vitro and in-vivo allow correlation and assignment of a spot size after focusing through the living eye. We discuss and analyze the results and show how trends in minimum visible lesion data should be assessed in light of chromatic aberration. National laser safety standards are based on minimal visual lesion (MVL) threshold studies in different animal models. The energy required for a retinal lesion depends upon may parameters including wavelength and retinal spot size. We attempt to explain trends in reported MVL threshold studies using a model of the eye which allows calculation of changes in retinal spot size due to chromatic aberration.

  1. Bolometric Arrays for Millimeter Wavelengths

    NASA Astrophysics Data System (ADS)

    Castillo, E.; Serrano, A.; Torres-Jácome, A.

    2009-11-01

    During last years, semiconductor bolometers using thin films have been developed at INAOE, specifically boron-doped hydrogenated amorphous silicon films. The characteristics shown by these devices made them attractive to be used in astronomical instrumentation, mainly in two-dimentional arrays. These detector arrays used at the Large Millimeter Telescope will make possible to obtain astronomical images in millimeter and sub-millimeter wavelengths. With this in mind, we are developing a method to produce, with enough reliability, bolometer arrays at INAOE. Until now, silicon nitride diaphragm arrays, useful as radiation absorbers, have succesfully been obtained. Sizes going from one to four millimeter by element in a consistent way; however we have not tested thermometers and metallic contact deposition yet. At the same time, we are working on two possible configurations for the readout electronics; one of them using commercial components while the other will be an integrated circuit specifically designed for this application. Both versions will work below 77K.

  2. Application of an all-solid-state diode-laser-based sensor for carbon monoxide detection by optical absorption in the 4.4--4.8 mum spectral region

    NASA Astrophysics Data System (ADS)

    Barron Jimenez, Rodolfo

    An all-solid-state continuous-wave (cw) laser system for mid-infrared absorption measurements of the carbon monoxide (CO) molecule has been developed and demonstrated. The single-mode, tunable output of an external-cavity diode laser (ECDL) is difference-frequency mixed (DFM) with the output of a 550-mW diode-pumped cw Nd:YAG laser in a periodically-poled lithium niobate (PPLN) crystal to produce tunable cw radiation in the mid-infrared. The wavelength of the 860-nm ECDL can be coarse tuned between 860.78 to 872.82 nm allowing the sensor to be operated in the 4.4--4.8 mum region. Results from single-pass mid-IR direct absorption experiments for CO concentration measurements are discussed. CO measurements were performed in CO/CO2/N 2 mixtures in a room temperature gas cell that allowed the evaluation of the sensor operation and data reduction procedures. Field testing was performed at two locations: in the exhaust of a well-stirred reactor (WSR) at Wright-Patterson Air Force Base and the exhaust of a gas turbine at Honeywell Engines and Systems. Field tests demonstrated the feasibility of the sensor for operation in harsh combustion environments but much improvement in the sensor design and operation was required. Experiments in near-adiabatic hydrogen/air CO2-doped flames were performed featuring two-line thermometry in the 4.8 mum spectral region. The sensor concentration measurement uncertainty was estimated at 2% for gas cell testing. CO concentration measurements agreed within 15% of conventional extractive sampling at WSR, and for the flame experiments the repeatability of the peak absorption gives a system uncertainty of 10%. The noise equivalent CO detection limit for these experiments was estimated at 2 ppm per meter, for combustion gas at 1000 K assuming a SNR ratio of 1.

  3. Optimized wavelength selection for molecular absorption thermometry.

    PubMed

    An, Xinliang; Caswell, Andrew W; Lipor, John J; Sanders, Scott T

    2015-04-01

    A differential evolution (DE) algorithm is applied to a recently developed spectroscopic objective function to select wavelengths that optimize the temperature precision of water absorption thermometry. DE reliably finds optima even when many-wavelength sets are chosen from large populations of wavelengths (here 120 000 wavelengths from a spectrum with 0.002 cm(-1) resolution calculated by 16 856 transitions). Here, we study sets of fixed wavelengths in the 7280-7520 cm(-1) range. When optimizing the thermometer for performance within a narrow temperature range, the results confirm that the best temperature precision is obtained if all the available measurement time is split judiciously between the two most temperature-sensitive wavelengths. In the wide temperature range case (thermometer must perform throughout 280-2800 K), we find (1) the best four-wavelength set outperforms the best two-wavelength set by an average factor of 2, and (2) a complete spectrum (all 120 000 wavelengths from 16 856 transitions) is 4.3 times worse than the best two-wavelength set. Key implications for sensor designers include: (1) from the perspective of spectroscopic temperature sensitivity, it is usually sufficient to monitor two or three wavelengths, depending on the sensor's anticipated operating temperature range; and (2) although there is a temperature precision penalty to monitoring a complete spectrum, that penalty may be small enough, particularly at elevated pressure, to justify the complete-spectrum approach in many applications.

  4. At-wavelength characterization of refractive x-ray lenses using a two-dimensional grating interferometer

    SciTech Connect

    Rutishauser, Simon; David, Christian; Zanette, Irene; Weitkamp, Timm; Donath, Tilman

    2011-11-28

    We report on the application of a two-dimensional hard x-ray grating interferometer to x-ray optics metrology. The interferometer is sensitive to refraction angles in two perpendicular directions with a precision of 10 nrad. It is used to observe the wavefront changes induced by a single parabolic beryllium focusing lens of large radius of curvature. The lens shape is reconstructed and its residual aberrations are analyzed. Its profile differs from an ideal parabolic shape by less than 2 {mu}m or {lambda}/50 at {lambda} = 0.54 A wavelength.

  5. THE MASS LOSS RETURN FROM EVOLVED STARS TO THE LARGE MAGELLANIC CLOUD: EMPIRICAL RELATIONS FOR EXCESS EMISSION AT 8 AND 24 {mu}m

    SciTech Connect

    Srinivasan, Sundar; Meixner, Margaret; Leitherer, Claus; Vijh, Uma; Gordon, Karl D.; Sewilo, Marta; Volk, Kevin; Blum, Robert D.; Harris, Jason; Babler, Brian L.; Bracker, Steve; Meade, Marilyn; Block, Miwa; Engelbracht, Charles W.; For, Bi-Qing; Misselt, Karl A.; Cohen, Martin; Hora, Joseph L.; Indebetouw, Remy; Markwick-Kemper, Francisca

    2009-06-15

    We present empirical relations describing excess emission from evolved stars in the Large Magellanic Cloud (LMC) using data from the Spitzer Space Telescope Surveying the Agents of a Galaxy's Evolution (SAGE) survey which includes the Infrared Array Camera (IRAC) 3.6, 4.5, 5.8, and 8.0 {mu}m and Multiband Imaging Photometer (MIPS) 24, 70, and 160 {mu}m bands. We combine the SAGE data with the Two Micron All Sky Survey (2MASS; J, H, and K {sub s}) and the optical Magellanic Cloud Photometric Survey (MCPS; U, B, V, and I) point source catalogs in order to create complete spectral energy distributions (SEDs) of the asymptotic giant branch (AGB) star candidates in the LMC. AGB star outflows are among the main producers of dust in a galaxy, and this mass loss results in an excess in the fluxes observed in the 8 and 24 {mu}m bands. The aim of this work is to investigate the mass loss return by AGB stars to the interstellar medium of the LMC by studying the dependence of the infrared excess flux on the total luminosity. We identify oxygen-rich, carbon-rich, and extreme AGB star populations in our sample based on their 2MASS and IRAC colors. The SEDs of oxygen- and carbon-rich AGB stars are compared with appropriate stellar photosphere models to obtain the excess flux in all the IRAC bands and the MIPS 24 {mu}m band. Extreme AGB stars are dominated by circumstellar emission at 8 and 24 {mu}m; thus we approximate their excesses with the flux observed in these bands. We find about 16,000 O-rich, 6300 C-rich, and 1000 extreme sources with reliable 8 {mu}m excesses, and about 4500 O-rich, 5300 C-rich, and 960 extreme sources with reliable 24 {mu}m excesses. The excesses are in the range 0.1 mJy to 5 Jy. The 8 and 24 {mu}m excesses for all three types of AGB candidates show a general increasing trend with luminosity. The color temperature of the circumstellar dust derived from the ratio of the 8 and 24 {mu}m excesses decreases with an increase in excess, while the 24 {mu}m

  6. Phase-shifting point-diffraction interferometry at EUV wavelengths

    SciTech Connect

    Goldberg, K.A.; Tejnil, E.; Sang Lee

    1997-04-01

    A novel phase-shifting point-diffraction interferometer (PS/PDI) operating at the Advanced Light Source (ALS) is being used to perform wavefront-measuring metrology at 13.4-nm wavelength to characterize aberrations in a multilayer-coated 10x Schwarzschild objective designed for extreme ultraviolet (EUV) projection lithography experiments. To achieve 0.1-micron critical dimension pattern transfer with EUV projection lithography at 13.4-nm wavelength, nearly diffraction-limited all-reflective multilayer-coated optical systems with 0.1 numerical aperture are required. The EUV wavefront, determined by the mirror surfaces and the reflective multilayer coatings, is measurable only at the operational wavelength of the system. The authors goal is to measure the EUV wavefront to an accuracy of 0.01 waves rms (0.13 nm). The PS/PDI is a type of point-diffraction interferometer, modified for significantly improved throughput and phase-shifting capability. The interferometer design utilizes a grating beamsplitter and pinhole spatial filters in the object and image planes of the optical system under test. The 10x-reduction Schwarzschild objective, with image-side numerical aperture of 0.08, is illuminated by a sub-micron pinhole in the object plane. A coarse, 20-micron pitch grating placed between the illumination pinhole and the Schwarzschild system serves a dual role as a small-angle beam-splitter and a phase-shifting element. The first-order diffracted beam from the grating is spatially filtered in the image plane of the Schwarzschild with a sub-100-nm pinhole and becomes the `D reference` wave in the interferometer. The zero-order beam is the `test` wave, and it passes unobstructed through a 4.5-{mu}m window in the image plane. The test and reference beams are separated by several microns in the image plane to minimize beam overlap. The interference fringes are recorded with a CCD detector placed about 12 cm from the Schwarzschild image plane.

  7. 3.6 AND 4.5 {mu}m PHASE CURVES AND EVIDENCE FOR NON-EQUILIBRIUM CHEMISTRY IN THE ATMOSPHERE OF EXTRASOLAR PLANET HD 189733b

    SciTech Connect

    Knutson, Heather A.; Lewis, Nikole; Showman, Adam P.; Fortney, Jonathan J.; Laughlin, Gregory; Burrows, Adam; Cowan, Nicolas B.; Agol, Eric; Aigrain, Suzanne; Charbonneau, David; Desert, Jean-Michel; Deming, Drake; Henry, Gregory W.; Langton, Jonathan

    2012-07-20

    We present new, full-orbit observations of the infrared phase variations of the canonical hot Jupiter HD 189733b obtained in the 3.6 and 4.5 {mu}m bands using the Spitzer Space Telescope. When combined with previous phase curve observations at 8.0 and 24 {mu}m, these data allow us to characterize the exoplanet's emission spectrum as a function of planetary longitude and to search for local variations in its vertical thermal profile and atmospheric composition. We utilize an improved method for removing the effects of intrapixel sensitivity variations and robustly extracting phase curve signals from these data, and we calculate our best-fit parameters and uncertainties using a wavelet-based Markov Chain Monte Carlo analysis that accounts for the presence of time-correlated noise in our data. We measure a phase curve amplitude of 0.1242% {+-} 0.0061% in the 3.6 {mu}m band and 0.0982% {+-} 0.0089% in the 4.5 {mu}m band, corresponding to brightness temperature contrasts of 503 {+-} 21 K and 264 {+-} 24 K, respectively. We find that the times of minimum and maximum flux occur several hours earlier than predicted for an atmosphere in radiative equilibrium, consistent with the eastward advection of gas by an equatorial super-rotating jet. The locations of the flux minima in our new data differ from our previous observations at 8 {mu}m, and we present new evidence indicating that the flux minimum observed in the 8 {mu}m is likely caused by an overshooting effect in the 8 {mu}m array. We obtain improved estimates for HD 189733b's dayside planet-star flux ratio of 0.1466% {+-} 0.0040% in the 3.6 {mu}m band and 0.1787% {+-} 0.0038% in the 4.5 {mu}m band, corresponding to brightness temperatures of 1328 {+-} 11 K and 1192 {+-} 9 K, respectively; these are the most accurate secondary eclipse depths obtained to date for an extrasolar planet. We compare our new dayside and nightside spectra for HD 189733b to the predictions of one-dimensional radiative transfer models from

  8. High output power and high temperature operation of 1. 5 /mu/m DFB-PPIBH laser diodes

    SciTech Connect

    Kakimoto, S.; Nakajima, Y.; Takemoto, A.; Yoshida, N.; Namizaki, H.; Susaki, W.

    1989-06-01

    Highly efficient 1.5 /mu/m distributed feedback p-substrate partially-inverted buried heterostructure laser diodes with a thin active layer have been developed using a metal-organic chemical vapor deposition technique. An average slope efficiency of 0.26 mW/mA (quantum efficiency 33 percent) and the maximum slope efficiency of 0.39 mW/mA (49 percent) were achieved. The full width at half maximum in the direction perpendicular to the junction plane of 25/sup 0/ was obtained. A high output power of 77 mW was obtained under a CW condition at room temperature. This laser diode laser up to 120/sup 0/C, and more than 10 mW was obtained, even at 90/sup 0/C.

  9. Single-molecule analysis of ultradilute solutions with guided streams of 1-{mu}m water droplets

    SciTech Connect

    Kung, C.; Barnes, M.D.; Lermer, N.; Whitten, W.B.; Ramsey, J.M.

    1999-03-01

    We describe instrumentation for real-time detection of single-molecule fluorescence in guided streams of 1-{mu}m (nominal) water droplets. In this technique, target molecules were confined to droplets whose volumes were comparable with illumination volumes in diffraction-limited fluorescence microscopy and guided to the waist of a cw probe laser with an electrostatic potential. Concentration detection limits for Rhodamine 6G in water were determined to be {approximately}1 fM, roughly 3 orders of magnitude lower than corresponding limits determined recently with diffraction-limited microscopy techniques for a chemical separation of similar dyes. In addition to its utility as a vehicle for probing single molecules, instrumentation for producing and focusing stable streams of 1{endash}2-{mu}m-diameter droplets may have other important analytical applications as well. {copyright} 1999 Optical Society of America

  10. QEPAS based detection of broadband absorbing molecules using a widely tunable, cw quantum cascade laser at 8.4 mum.

    PubMed

    Lewicki, Rafal; Wysocki, Gerard; Kosterev, Anatoliy A; Tittel, Frank K

    2007-06-11

    Detection of molecules with wide unresolved rotationa-lvibrational absorption bands is demonstrated by using Quartz Enhanced Photoacoustic Spectroscopy and an amplitude modulated, high power, thermoelectrically cooled quantum cascade laser operating at 8.4 mum in an external cavity configuration. The laser source exhibits single frequency tuning of 135 cm-1 with a maximum optical output power of 50 mW. For trace-gas detection of Freon 125 (pentafluoroethane) at 1208.62 cm-1 a normalized noise equivalent absorption coefficient of NNEA=2.64x10(-9) cm?(-1)W/Hz(1/2)was obtained. Noise equivalent sensitivity at ppbv level as well as spectroscopic chemical analysis of a mixture of two broadband absorbers (Freon 125 and acetone) with overlapping absorption spectra were demonstrated.

  11. Establishment and characterization of a unique 1 {mu}m diameter liver-derived progenitor cell line

    SciTech Connect

    Aravalli, Rajagopal N.; Behnan Sahin, M.; Cressman, Erik N.K.; Steer, Clifford J.

    2010-01-01

    Liver-derived progenitor cells (LDPCs) are recently identified novel stem/progenitor cells from healthy, unmanipulated adult rat livers. They are distinct from other known liver stem/progenitor cells such as the oval cells. In this study, we have generated a LDPC cell line RA1 by overexpressing the simian virus 40 (SV40) large T antigen (TAg) in primary LDPCs. This cell line was propagated continuously for 55 passages in culture, after which it became senescent. Interestingly, following transformation with SV40 TAg, LDPCs decreased in size significantly and the propagating cells measured 1 {mu}m in diameter. RA1 cells proliferated in vitro with a doubling time of 5-7 days, and expressed cell surface markers of LDPCs. In this report, we describe the characterization of this novel progenitor cell line that might serve as a valuable model to study liver cell functions and stem cell origin of liver cancers.

  12. Wavelength Anomalies in UV-Vis Spectrophotometry

    NASA Astrophysics Data System (ADS)

    Tellinghuisen, J.

    2012-06-01

    Commercial spectrophotometers are great tools for recording absorption spectra of low-to-moderate resolution and high photometic quality. However, in the case of at least one such instrument, the Shimadzu UV-2101PC (and by assumption, similar Shimadzu models), the wavelength accuracy may not match the photometric accuracy. In fact the wavelength varies with slit width, spectral sampling interval, and even the specified range, with a smoothing algorithm invoked any time the spectrum includes more than 65 sampled wavelengths. This behavior appears not to be documented anywhere, but it has been present for at least 20 years and persists even in the latest software available to run the instrument. The wavelength shifts can be as large as 1 nm, so for applications where wavelength accuracy better than this is important, wavelength calibration must be done with care to ensure that the results are valid for the parameters used to record the target spectra.

  13. Laser wavelength meter: analysis of measurement uncertainties

    NASA Astrophysics Data System (ADS)

    Skrzeczanowski, Wojciech; Zyczkowski, Marek; Dlugaszek, Andrzej

    1999-08-01

    Principle of operation of laser radiation wavelength meter based on Fabry-Perot interferometer and linear CCD camera is presented in the paper. A dependence, on the base of which laser wavelength can be calculated, is found and a way of defining of all component uncertainties of a measurement is shown. An analysis of an influence and examples of definition of uncertainties of a measurement for four wavelength meter structural sets of different objective focal lengths are presented.

  14. Wavelength-doubling optical parametric oscillator

    DOEpatents

    Armstrong, Darrell J.; Smith, Arlee V.

    2007-07-24

    A wavelength-doubling optical parametric oscillator (OPO) comprising a type II nonlinear optical medium for generating a pair of degenerate waves at twice a pump wavelength and a plurality of mirrors for rotating the polarization of one wave by 90 degrees to produce a wavelength-doubled beam with an increased output energy by coupling both of the degenerate waves out of the OPO cavity through the same output coupler following polarization rotation of one of the degenerate waves.

  15. Multi-wavelength differential absorption measurements of chemical species

    NASA Astrophysics Data System (ADS)

    Brown, David M.

    The probability of accurate detection and quantification of airborne species is enhanced when several optical wavelengths are used to measure the differential absorption of molecular spectral features. Characterization of minor atmospheric constituents, biological hazards, and chemical plumes containing multiple species is difficult when using current approaches because of weak signatures and the use of a limited number of wavelengths used for identification. Current broadband systems such as Differential Optical Absorption Spectroscopy (DOAS) have either limitations for long-range propagation, or require transmitter power levels that are unsafe for operation in urban environments. Passive hyperspectral imaging systems that utilize absorption of solar scatter at visible and infrared wavelengths, or use absorption of background thermal emission, have been employed routinely for detection of airborne chemical species. Passive approaches have operational limitations at various ranges, or under adverse atmospheric conditions because the source intensity and spectrum is often an unknown variable. The work presented here describes a measurement approach that uses a known source of a low transmitted power level for an active system, while retaining the benefits of broadband and extremely long-path absorption operations. An optimized passive imaging system also is described that operates in the 3 to 4 mum window of the mid-infrared. Such active and passive instruments can be configured to optimize the detection of several hydrocarbon gases, as well as many other species of interest. Measurements have provided the incentive to develop algorithms for the calculations of atmospheric species concentrations using multiple wavelengths. These algorithms are used to prepare simulations and make comparisons with experimental results from absorption data of a supercontinuum laser source. The MODTRAN model is used in preparing the simulations, and also in developing additional

  16. Optimizing constant wavelength neutron powder diffractometers

    NASA Astrophysics Data System (ADS)

    Cussen, Leo D.

    2016-06-01

    This article describes an analytic method to optimize constant wavelength neutron powder diffractometers. It recasts the accepted mathematical description of resolution and intensity in terms of new variables and includes terms for vertical divergence, wavelength and some sample scattering effects. An undetermined multiplier method is applied to the revised equations to minimize the RMS value of resolution width at constant intensity and fixed wavelength. A new understanding of primary spectrometer transmission (presented elsewhere) can then be applied to choose beam elements to deliver an optimum instrument. Numerical methods can then be applied to choose the best wavelength.

  17. Effective wavelength for multicolor/pyrometry.

    PubMed

    Gardner, J L

    1980-09-15

    The concept of a temperature varying effective wavelength has recently been applied in multiwavelength pyrometry. The effective wavelength is shown to be discontinuous at a particular temperature, and the properties of the effective wavelength over a wide temperature range are explained. It is shown that a simple relationship is sufficient to calculate the effective wavelength and hence radiance at a given temperature without resorting to a convolution integration, in particular where broad filters are used to improve signal levels in a pyrometer. PMID:20234565

  18. Radio frequency controlled synthetic wavelength sweep for absolute distance measurement by optical interferometry

    SciTech Connect

    Le Floch, Sebastien; Salvade, Yves; Mitouassiwou, Rostand; Favre, Patrick

    2008-06-01

    We present a new technique applied to the variable optical synthetic wavelength generation in optical interferometry. It consists of a chain of optical injection locking among three lasers: first a distributed-feedback laser is used as a master to injection lock an intensity-modulated laser that is directly modulated around 15 GHz by a radio frequency generator on a sideband. A second distributed-feedback laser is injection locked on another sideband of the intensity-modulated laser. The variable synthetic wavelength for absolute distance measurement is simply generated by sweeping the radio frequency over a range of several hundred megahertz, which corresponds to the locking range of the two slave lasers. In this condition, the uncertainty of the variable synthetic wavelength is equivalent to the radio frequency uncertainty. This latter has a relative accuracy of 10{sup -7} or better, resulting in a resolution of {+-}25 {mu}m for distances exceeding tens of meters. The radio frequency generator produces a linear frequency sweep of 1 ms duration (i.e., exactly equal to one absolute distance measurement acquisition time), with frequency steps of about 1 MHz. Finally, results of absolute distance measurements for ranges up to 10 m are presented.

  19. On the potential of mid-IR lasers for generating high harmonics with subnanometer wavelengths in gases

    SciTech Connect

    Emelin, M Yu; Ryabikin, M Yu

    2013-03-31

    The influence of the magnetic field of a laser pulse and the depletion of bound levels of working-medium atoms on the generation of high harmonics of mid-IR laser radiation in gases is investigated using numerical quantum-mechanical calculations. The maximum attainable spectral widths of high harmonics are estimated for model atoms with different ionisation potentials taking into account the aforementioned limiting effects. It is shown (within a two-dimensional model) that high harmonics with wavelengths to several angstroms can be generated by irradiating helium atoms with high-power femtosecond pulses of a laser [5] with a centre wavelength of 3.9 {mu}m. The possibility of observing experimentally relativistic effects using modern desktop mid-IR laser sources is demonstrated. (extreme light fields and their applications)

  20. Relativistic Single-Cycled Short-Wavelength Laser Pulse Compressed from a Chirped Pulse Induced by Laser-Foil Interaction

    SciTech Connect

    Ji, L. L.; Shen, B. F.; Li, D. X.; Wang, D.; Leng, Y. X.; Zhang, X. M.; Wen, M.; Wang, W. P.; Xu, J. C.; Yu, Y. H.

    2010-07-09

    By particle-in-cell simulation and analysis, we propose a plasma approach to generate a relativistic chirped pulse based on a laser-foil interaction. When two counterpropagating circularly polarized pulses interact with an overdense foil, the driving pulse (with a larger laser field amplitude) will accelerate the whole foil to form a double-layer structure, and the scattered pulse (with a smaller laser field amplitude) is reflected by this flying layer. Because of the Doppler effect and the varying velocity of the layer, the reflected pulse is up-shifted for frequency and chirped; thus, it could be compressed to a nearly single-cycled relativistic laser pulse with a short wavelength. Simulations show that a nearly single-cycled subfemtosecond relativistic pulse can be generated with a wavelength of 0.2 {mu}m after dispersion compensation.

  1. THE ORIGIN OF THE 3.4 {mu}m FEATURE IN WILD 2 COMETARY PARTICLES AND IN ULTRACARBONACEOUS INTERPLANETARY DUST PARTICLES

    SciTech Connect

    Matrajt, G.; Flynn, G.; Brownlee, D.; Joswiak, D.; Bajt, S.

    2013-03-10

    We analyzed two ultracarbonaceous interplanetary dust particles (IDPs) and two cometary Wild 2 particles with infrared spectroscopy. We characterized the carrier of the 3.4 {mu}m band in these samples and compared its profile and the CH{sub 2}/CH{sub 3} ratios to the 3.4 {mu}m band in the diffuse interstellar medium (DISM), in the insoluble organic matter from three primitive meteorites, in asteroid 24 Themis, and in the coma of comet 103P/Hartley 2. We found that the 3.4 {mu}m band in both Wild 2 and IDPs is similar, but different from all of the other astrophysical environments that we compared it to. The 3.4 {mu}m band in the IDPs and Wild 2 particles is dominated by CH{sub 2} groups, the peaks are narrower and stronger than in the meteorites, asteroid Themis, and the DISM. Also, the presence of the carbonyl group C=O at {approx}1700 cm{sup -1} (5.8 {mu}m) in most of the spectra of our samples indicates that these aliphatic chains have O bonded to them, which is quite different from astronomical spectra of the DISM. Based on all of these observations, we conclude that the origin of the carrier of the 3.4 {mu}m band in the IDPs and Wild 2 samples is not interstellar; instead, we suggest that the origin lies in the outermost parts of the solar nebula.

  2. Fourfold output power enhancement and threshold reduction through thermal effects in an Er(3+)/Yb(3+)-codoped optical fiber laser excited at 1.064 mum.

    PubMed

    da Silva, C J; de Araujo, M T; Gouveia, E A; Gouveia-Neto, A S

    1999-09-15

    Thermally induced output power enhancement and threshold reduction in an Er(3+)/Yb(3+) -codoped optical fiber laser at 1.54mum pumped by 1.064-mu;m cw radiation is demonstrated. Steady fourfold output power increase and threshold decrease were achieved by heating of the Yb(3+) -sensitized Er(3+) -doped fiber laser medium in the temperature range 23-150 degrees C degrees . The laser efficiency thermal behavior is assigned to the temperature-dependent effective absorption cross section of the ytterbium sensitizer through the so-called multiphonon-assisted anti-Stokes excitation process. PMID:18079782

  3. Semiconductor laser with multiple lasing wavelengths

    DOEpatents

    Fischer, Arthur J.; Choquette, Kent D.; Chow, Weng W.

    2003-07-29

    A new class of multi-terminal vertical-cavity semiconductor laser components has been developed. These multi-terminal laser components can be switched, either electrically or optically, between distinct lasing wavelengths, or can be made to lase simultaneously at multiple wavelengths.

  4. Optical wavelength modulation in free electron lasers

    SciTech Connect

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

    1995-12-31

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

  5. GHRS Cycle 5 Echelle Wavelength Monitor

    NASA Astrophysics Data System (ADS)

    Soderblom, David

    1995-07-01

    This proposal defines the spectral lamp test for Echelle A. It is an internal test which makes measurements of the wavelength lamp SC2. It calibrates the carrousel function, Y deflections, resolving power, sensitivity, and scattered light. The wavelength calibration dispersion constants will be updated in the PODPS calibration data base. This proposal defines the spectral lamp test for Echelle B. It is an internal test which makes measurements of the wavelength lamp SC2. It calibrates the carrousel function, Y deflections, resolving power, sensitivity, and scattered light. The wavelength calibration dispersion constants will be updated in the PODPS calibration data base. It will be run every 4 months. The wavelengths may be out of range according to PEPSI or TRANS. Please ignore the errors.

  6. Comparative Study of Probiotic Ice Cream and Probiotic Drink on Salivary Streptococcus mutans Levels in 6-12 Years Age Group Children

    PubMed Central

    Mahantesha, Taranatha; Reddy, K M Parveen; Kumar, N H Praveen; Nara, Asha; Ashwin, Devasya; Buddiga, Vinutna

    2015-01-01

    Background: Dental caries is one of the most common health problems in the world. Probiotics are one the various preventive methods to reduce dental caries. The aim of this study is to compare the effectiveness of probiotic ice cream and drink on salivary Streptococcus mutans levels in children of 6-12 years age group. Materials and Methods: A three phase study was carried out in children (n = 50) of 6-12 years age with zero decayed missing filled teeth (dmft)/DMFT. They were randomly divided into two equal groups. Saliva samples were collected before the consumptions of probiotic ice cream and probiotic drink. Colony count obtained was recorded as baseline data. For both groups probiotic ice cream and drink was given randomly for 7 days and a washout period of 90 days were given and then the saliva samples were collected and colony counting was done. Results: Statistical analysis was performed using Student’s paired t-test and multiple comparisons by Tukey’s honest significant difference test which showed, there is a significant reduction in salivary S. mutans level in both groups after 7 days period. However, after washout period only probiotic ice cream showed reduction whereas drink did not. Also, there was no significant difference between probiotic ice cream and drink. Conclusion: Probiotic organisms definitely have a role in reducing the salivary S. mutans level and ice cream would be a better choice than drink. However, the prolonged use of the agents and their effects on caries is still to be determined. PMID:26435616

  7. National survey of psychologists' training and practice in breaking bad news: a mixed methods study of the MUM effect.

    PubMed

    Merker, Brad M; Hanson, William E; Poston, John M

    2010-09-01

    Research on breaking bad news has involved undergraduates, medical students, and physicians. However, to date, no studies have examined how, or whether, psychologists are trained to break bad news, as well as their current practice of breaking bad news. This mixed methods study explored the training and practice of 329 licensed psychologists/APA members in breaking bad news, using the MUM effect as a theoretical backdrop. Results suggest (1) psychologists are, as hypothesized, significantly more reluctant to break bad news than good news, (2) anxiety accounts for 30.6% of the variance in their reluctance, and (3) three-out-of-four psychologists break bad news "to some extent" or more, most typically related to a patient's psychological health, major Axis I diagnosis, or learning disability. Results also suggest most psychologists are not trained to break bad news, with only 2.7% being familiar with existing recommendations and guidelines; and anxiety, concerns for self/other, context, and norms play an important role in the bad news breaking process. Implications for theory, research, and practice are discussed and a training model is proposed. PMID:20499268

  8. Wavelengths effective in induction of malignant melanoma

    SciTech Connect

    Setlow, R.B.; Grist, E.; Thompson, K.; Woodhead, A.D. )

    1993-07-15

    It is generally agreed that sunlight exposure is one of the etiologic agents in malignant melanoma of fair-skinned individuals. However, the wavelengths responsible for tumorigenesis are not known, although DNA is assumed to be the target because individuals defective in the repair of UV damage to DNA are several thousandfold more prone to the disease than the average population. Heavily pigmented back-cross hybrids of the genus Xiphophorus (platyfish and swordtails) are very sensitive to melanoma induction by single exposures to UV. The authors irradiated groups of five 6-day-old fish with narrow wavelength bands at 302, 313, 365, 405, and 436 nm and score the irradiated animals for melanomas 4 months later. They used several exposures at each wavelength to obtain estimates of the sensitivity for melanoma induction as a function of exposure and wavelength. The action spectrum (sensitivity per incident photon as a function of wavelength) for melanoma induction shows appreciable sensitivity at 365, 405, and probably 436 nm, suggesting that wavelengths not absorbed directly in DNA are effective in induction. They interpret the results as indicating that light energy absorbed in melanin is effective in inducing melanomas in this animal model and that, in natural sunlight, 90-95% of melanoma induction may be attributed to wavelengths >320 nm-the UV-A and visible spectral regions. 25 refs., 4 figs., 1 tab.

  9. Short wavelength FELs using the SLAC linac

    SciTech Connect

    Winick, H.; Bane, K.; Boyce, R.

    1993-08-01

    Recent technological developments have opened the possibility to construct a device which we call a Linac Coherent Light Source (LCLS); a fourth generation light source, with brightness, coherence, and peak power far exceeding other sources. Operating on the principle of the free electron laser (FEL), the LCLS would extend the range of FEL operation to much aborter wavelength than the 240 mn that has so far been reached. We report the results of studies of the use of the SLAC linac to drive an LCLS at wavelengths from about 3-100 nm initially and possibly even shorter wavelengths in the future. Lasing would be achieved in a single pass of a low emittance, high peak current, high energy electron beam through a long undulator. Most present FELs use an optical cavity to build up the intensity of the light to achieve lasing action in a low gain oscillator configuration. By eliminating the optical cavity, which is difficult to make at short wavelengths, laser action can be extended to shorter wavelengths by Self-Amplified-Spontaneous-Emission (SASE), or by harmonic generation from a longer wavelength seed laser. Short wavelength, single pass lasers have been extensively studied at several laboratories and at recent workshops.

  10. Experimental verification of acoustic trace wavelength enhancement.

    PubMed

    Cray, Benjamin A

    2015-12-01

    Directivity is essentially a measure of a sonar array's beamwidth that can be obtained in a spherically isotropic ambient noise field; narrow array mainbeam widths are more directive than broader mainbeam widths. For common sonar systems, the directivity factor (or directivity index) is directly proportional to the ratio of an incident acoustic trace wavelength to the sonar array's physical length (which is always constrained). Increasing this ratio, by creating additional trace wavelengths for a fixed array length, will increase array directivity. Embedding periodic structures within an array generates Bragg scattering of the incident acoustic plane wave along the array's surface. The Bragg scattered propagating waves are shifted in a precise manner and create shorter wavelength replicas of the original acoustic trace wavelength. These replicated trace wavelengths (which contain identical signal arrival information) increase an array's wavelength to length ratio and thus directivity. Therefore, a smaller array, in theory, can have the equivalent directivity of a much larger array. Measurements completed in January 2015 at the Naval Undersea Warfare Center's Acoustic Test Facility, in Newport, RI, verified, near perfectly, these replicated, shorter, trace wavelengths. PMID:26723331

  11. Wavelengths Effective in Induction of Malignant Melanoma

    NASA Astrophysics Data System (ADS)

    Setlow, Richard B.; Grist, Eleanor; Thompson, Keith; Woodhead, Avril D.

    1993-07-01

    It is generally agreed that sunlight exposure is one of the etiologic agents in malignant melanoma of fair-skinned individuals. However, the wavelengths responsible for tumorigenesis are not known, although DNA is assumed to be the target because individuals defective in the repair of UV damage to DNA are several thousandfold more prone to the disease than the average population. Heavily pigmented backcross hybrids of the genus Xiphophorus (platyfish and swordtails) are very sensitive to melanoma induction by single exposures to UV. We irradiated groups of five 6-day-old fish with narrow wavelength bands at 302, 313, 365, 405, and 436 nm and scored the irradiated animals for melanomas 4 months later. We used several exposures at each wavelength to obtain estimates of the sensitivity for melanoma induction as a function of exposure and wavelength. The action spectrum (sensitivity per incident photon as a function of wavelength) for melanoma induction shows appreciable sensitivity at 365, 405, and probably 436 nm, suggesting that wavelengths not absorbed directly in DNA are effective in induction. We interpret the results as indicating that light energy absorbed in melanin is effective in inducing melanomas in this animal model and that, in natural sunlight, 90-95% of melanoma induction may be attributed to wavelengths > 320 nm-the UV-A and visible spectral regions.

  12. Multiple Wavelength Observations of Flaring Active Regions

    NASA Astrophysics Data System (ADS)

    Lang, Kenneth R.

    The radio emission of quiescent active regions at 6 cm wavelength marks the legs of magnetic dipoles, and the emission at 20 cm wavelength delineates the radio wavelength counterpart of the coronal loops previously detected at X-ray wavelengths. At both wavelengths the temperatures have coronal values of a few million degrees. The polarization of the radio emission specifies the structure and strength of the coronal magnetic field (H ≈ 600 Gauss at heights h ≈ 4 x 109 cm above sunspot umbrae). At 6 cm and 20 cm wavelength the solar bursts have angular sizes between 5" and 30", brightness temperatures between 2 x 107 K and 2 x 108 K, and degrees of circular polarization between 10% and 90%. The location of the burst energy release is specified with second-of-arc accuracy. At radio wavelengths the bursts occur within the central regions of magnetic loops, while the flaring Ha kernels are located at the loop footpoints. Coronal loops exhibit enhanced radio emission (preburst heating) a few minutes before the release of burst energy. The radio polarization data indicate magnetic changes before and during solar bursts.

  13. Experimental verification of acoustic trace wavelength enhancement.

    PubMed

    Cray, Benjamin A

    2015-12-01

    Directivity is essentially a measure of a sonar array's beamwidth that can be obtained in a spherically isotropic ambient noise field; narrow array mainbeam widths are more directive than broader mainbeam widths. For common sonar systems, the directivity factor (or directivity index) is directly proportional to the ratio of an incident acoustic trace wavelength to the sonar array's physical length (which is always constrained). Increasing this ratio, by creating additional trace wavelengths for a fixed array length, will increase array directivity. Embedding periodic structures within an array generates Bragg scattering of the incident acoustic plane wave along the array's surface. The Bragg scattered propagating waves are shifted in a precise manner and create shorter wavelength replicas of the original acoustic trace wavelength. These replicated trace wavelengths (which contain identical signal arrival information) increase an array's wavelength to length ratio and thus directivity. Therefore, a smaller array, in theory, can have the equivalent directivity of a much larger array. Measurements completed in January 2015 at the Naval Undersea Warfare Center's Acoustic Test Facility, in Newport, RI, verified, near perfectly, these replicated, shorter, trace wavelengths.

  14. Wavelength initialization employing wavelength recognition scheme in WDM-PON based on tunable lasers

    NASA Astrophysics Data System (ADS)

    Mun, Sil-Gu; Lee, Eun-Gu; Lee, Jong Hyun; Lee, Sang Soo; Lee, Jyung Chan

    2015-01-01

    We proposed a simple method to initialize the wavelength of tunable lasers in WDM-PON employing wavelength recognition scheme with an optical filter as a function of wavelength and accomplished plug and play operation. We also implemented a transceiver based on our proposed wavelength initialization scheme and then experimentally demonstrated the feasibility in WDM-PON configuration guaranteeing 16 channels with 100 GHz channel spacing. Our proposal is a cost-effective and easy-to-install method to realize the wavelength initialization of ONU. In addition, this method will support compatibility with all kind of tunable laser regardless of their structures and operating principles.

  15. Photovoltaic effect in water induced by a 2.92-{mu}m Cr{sup 3+}:Yb{sup 3+}:Ho{sup 3+}: YSGG laser

    SciTech Connect

    Il'ichev, Nikolai N; Kulevskii, L A; Pashinin, Pavel P

    2005-10-31

    The appearance of the potential difference is observed on electrodes placed in a cell with water irradiated by a Q-switched 2.92-{mu}m Cr{sup 3+}:Yb{sup 3+}:Ho{sup 3+}:YSGG laser. (interaction of laser radiation with matter. laser plasma)

  16. Engineering reverse saturable absorbers for desired wavelengths

    NASA Astrophysics Data System (ADS)

    Band, Yehuda B.; Scharf, Benjamin

    1986-06-01

    A variety of applications exist for reverse saturable absorbers (RSAs) in laser science (RSAs are substances whose excited-state absorption cross section is larger than their ground-state absorption cross section at a given wavelength and possess a number of other properties). We propose an approach to designing RSAs at a desired wavelength by construction of dimers of dye molecules which absorb near the wavelength of interest. The dimer ground-state absorption is to a state in which the excitation is spread over both monomeric units and the excited-state absorption commences from this state to the doubly excited electronic state in which both monomeric units are excited.

  17. Magic wavelengths for terahertz clock transitions

    SciTech Connect

    Zhou Xiaoji; Xu Xia; Chen Xuzong; Chen Jingbiao

    2010-01-15

    Magic wavelengths for laser trapping of boson isotopes of alkaline-earth metal atoms Sr, Ca, and Mg are investigated while considering terahertz clock transitions between the {sup 3}P{sub 0}, {sup 3}P{sub 1}, and {sup 3}P{sub 2} metastable triplet states. Our calculation shows that magic wavelengths for laser trapping do exist. This result is important because those metastable states have already been used to make accurate clocks in the terahertz frequency domain. Detailed discussions for magic wavelengths for terahertz clock transitions are given in this article.

  18. Laser wavelength metrology with color sensor chips.

    PubMed

    Jones, Tyler B; Otterstrom, Nils; Jackson, Jarom; Archibald, James; Durfee, Dallin S

    2015-12-14

    We present a laser wavelength meter based on a commercial color sensor chip. The chip consists of an array of photodiodes with different absorptive color filters. By comparing the relative amplitudes of light on the photodiodes, the wavelength of light can be determined. In addition to absorption in the filters, etalon effects add additional spectral features which improve the precision of the device. Comparing the measurements from the device to a commercial wavelength meter and to an atomic reference, we found that the device has picometer-level precision and picometer-scale drift over a period longer than a month. PMID:26699036

  19. Multimode fiber optic wavelength division multiplexing

    NASA Technical Reports Server (NTRS)

    Spencer, J. L.

    1982-01-01

    Optical wavelength division multiplexing (WDM) systems, with signals transmitted on different wavelengths through a single optical fiber, can have increased bandwidth and fault isolation properties over single wavelength optical systems. Two WDM system designs that might be used with multimode fibers are considered and a general description of the components which could be used to implement the system are given. The components described are sources, multiplexers, demultiplexers, and detectors. Emphasis is given to the demultiplexer technique which is the major developmental component in the WDM system.

  20. Multiple wavelength photolithography for preparing multilayer microstructures

    SciTech Connect

    Dentinger, Paul Michael; Krafcik, Karen Lee

    2003-06-24

    The invention relates to a multilayer microstructure and a method for preparing thereof. The method involves first applying a first photodefinable composition having a first exposure wavelength on a substrate to form a first polymeric layer. A portion of the first photodefinable composition is then exposed to electromagnetic radiation of the first exposure wavelength to form a first pattern in the first polymeric layer. After exposing the first polymeric layer, a second photodefinable composition having a second exposure wavelength is applied on the first polymeric layer to form a second polymeric layer. A portion of the second photodefinable composition is then exposed to electromagnetic radiation of the second exposure wavelength to form a second pattern in the second polymeric layer. In addition, a portion of each layer is removed according to the patterns to form a multilayer microstructure having a cavity having a shape that corresponds to the portions removed.

  1. Multiple-Wavelength Pyrometry Independent Of Emissivity

    NASA Technical Reports Server (NTRS)

    Ng, Daniel

    1996-01-01

    Multiple-wavelength pyrometric method provides for determination of two sequential temperatures of same surface or temperatures of two surfaces made of same material. Temperatures measured, without knowing emissivity, by uncalibrated spectral radiometer.

  2. Controllable Dual-Wavelength Fiber Laser

    NASA Astrophysics Data System (ADS)

    Li, Zhen; Zhou, Jun; He, Bing; Liu, Hou-Kang; Liu, Chi; Wei, Yun-Rong; Dong, Jing-Xing; Lou, Qi-Hong

    2012-07-01

    We demonstrate a controllable dual-wavelength fiber laser which contains a master laser and a slave laser. The master laser is a kind of ring cavity laser which can be injected into by the slave laser. The output laser wavelength is controlled by injected power of the slave laser; both single- and dual-wavelength operation can be achieved. Under free running, the master laser generates 1064 nm laser output. Here the slave laser is a 1072 nm fiber laser. The 1064 nm and 1072 nm laser coexist in output spectrum for relatively low injected power. Dual-wavelength and power-ratio-tunable operation can be achieved. If the injected power of the slave laser is high enough, the 1064 nm laser is extinguished automatically and there is only 1072 nm laser output.

  3. Wavelength mismatch effect in electromagnetically induced absorption

    NASA Astrophysics Data System (ADS)

    Bharti, Vineet; Wasan, Ajay; Natarajan, Vasant

    2016-07-01

    We present a theoretical investigation of the phenomenon of electromagnetically induced absorption (EIA) in a 4-level system consisting of vee and ladder subsystems. The four levels are coupled using one weak probe field, and two strong control fields. We consider an experimental realization using energy levels of Rb. This necessitates dealing with different conditions of wavelength mismatch-near-perfect match where all three wavelengths are approximately equal; partial mismatch where the wavelength of one control field is less than the other fields; and complete mismatch where all three wavelengths are unequal. We present probe absorption profiles with Doppler averaging at room temperature to account for experiments in a room temperature Rb vapor cell. Our analysis shows that EIA resonances can be studied using Rydberg states excited with diode lasers.

  4. Grating cavity dual wavelength dye laser.

    PubMed

    Zapata-Nava, Oscar Javier; Rodríguez-Montero, Ponciano; Iturbe-Castillo, M David; Treviño-Palacios, Carlos Gerardo

    2011-02-14

    We report simultaneous dual wavelength dye laser emission using Littman-Metcalf and Littrow cavity configurations with minimum cavity elements. Dual wavelength operation is obtained by laser operation in two optical paths inside the cavity, one of which uses reflection in the circulating dye cell. Styryl 14 laser dye operating in the 910 nm to 960 nm was used in a 15%:85% PC/EG solvent green pumped with a Q-switched doubled Nd3+:YAG laser. PMID:21369171

  5. Observations of Venus at 1-meter wavelength

    NASA Astrophysics Data System (ADS)

    Butler, Bryan J.

    2014-11-01

    Radio wavelength observations of Venus (including from the Magellan spacecraft) have been a powerful method of probing its surface and atmosphere since the 1950's. The emission is generally understood to come from a combination of emission and absorption in the subsurface, surface, and atmosphere at cm and shorter wavelengths [1]. There is, however, a long-standing mystery regarding the long wavelength emission from Venus. First discovered at wavelengths of 50 cm and greater [2], the effect was later confirmed to extend to wavelengths as short as 13 cm [1,3]. The brightness temperatures are depressed significantly 50 K around 10-20 cm, increasing to as much as 200 K around 1 m) from what one would expect from a "normal" surface (e.g., similar to the Moon or Earth) [1-3].No simple surface and subsurface model of Venus can reproduce these large depressions in the long wavelength emission [1-3]. Simple atmospheric and ionospheric models fail similarly. In an attempt to constrain the brightness temperature spectrum more fully, new observations have been made at wavelengths that cover the range 60 cm to 1.3 m at the Very Large Array, using the newly available low-band receiving systems there [4]. The new observations were made over a very wide wavelength range and at several Venus phases, with that wide parameter space coverage potentially allowing us to pinpoint the cause of the phenomenon. The observations and potential interpretations will be presented and discussed.[1] Butler et al. 2001, Icarus, 154, 226. [2] Schloerb et al. 1976, Icarus, 29, 329; Muhleman et al. 1973, ApJ, 183, 1081; Condon et al. 1973, ApJ, 183, 1075; Kuzmin 1965, Radiophysics. [3] Butler & Sault 2003, IAUSS, 1E, 17B. [4] Intema et al. 2014, BASI, 1.

  6. CALIBRATION OF [O IV] 26 {mu}m AS A MEASURE OF INTRINSIC ACTIVE GALACTIC NUCLEUS LUMINOSITY

    SciTech Connect

    Rigby, J. R.; Diamond-Stanic, A. M.; Aniano, G.

    2009-08-01

    We compare [O IV] 25.89 {mu}m emission line luminosities with very hard (10-200 keV) X-rays from Swift, INTEGRAL, and BeppoSAX for a complete sample of 89 Seyferts from the Revised Shapley-Ames sample. Using Seyfert 1s, we calibrate [O IV] as a measure of active galactic nucleus (AGN) intrinsic luminosity, for particular use in high-obscuration environments. With this calibration, we measure the average decrement in 14-195 keV X-ray to [O IV] luminosity ratio for Seyfert 2s compared to type 1s. We find a decrement of 3.1 {+-} 0.8 for Seyfert 2s, and a decrement of 5.0 {+-} 2.7 for known Compton-thick Seyfert 2s. These decrements imply column densities of approximately log N{sub H} = 24.6 cm{sup -2} and 24.7 cm{sup -2}, respectively. Thus, we infer that the average Seyfert 2 is more highly obscured and intrinsically more luminous than would be inferred even from the very hard X-rays. We demonstrate two applications of the hard X-ray to [O IV] ratio. For the extremely obscured NGC 1068, we measure a column density of log N{sub H} = 25.3-25.4 cm{sup -2}. Finally, by comparing [O IV] luminosities to total infrared luminosities for 12 bright ultraluminous infrared galaxies, we find that four have substantial AGN contributions.

  7. Dual-Wavelength Terahertz Metasurfaces with Independent Phase and Amplitude Control at Each Wavelength

    NASA Astrophysics Data System (ADS)

    Ding, Jun; Xu, Ningning; Ren, Han; Lin, Yuankun; Zhang, Weili; Zhang, Hualiang

    2016-09-01

    We have designed, fabricated and characterized dual-wavelength metasurfaces that function at two assigned terahertz wavelengths with independent phase and amplitude control at each wavelength. Specifically, we have designed a dual-wavelength achromatic metasurface-based deflector deflecting the incident wave to the same direction at two selected wavelengths, which has circumvented the critical limitation of strong wavelength dependence in the planar metasurface-based devices caused by the resonant nature of the plasmonic structures. As a proof of concept demonstration, the designed dual-wavelength achromatic deflector has been fabricated, and characterized experimentally. The numerical simulations, theoretical predictions, and experimental results agree very well with each other, demonstrating the property of independently manipulating the phase profiles at two wavelengths. Furthermore, another unique feature of the designed metasurface is that it can independently tailor both the phase and amplitude profiles at two wavelengths. This property has been numerically validated by engineering a metasurface-based device to simultaneously generate two diffraction orders at two desired wavelengths.

  8. Dual-Wavelength Terahertz Metasurfaces with Independent Phase and Amplitude Control at Each Wavelength

    PubMed Central

    Ding, Jun; Xu, Ningning; Ren, Han; Lin, Yuankun; Zhang, Weili; Zhang, Hualiang

    2016-01-01

    We have designed, fabricated and characterized dual-wavelength metasurfaces that function at two assigned terahertz wavelengths with independent phase and amplitude control at each wavelength. Specifically, we have designed a dual-wavelength achromatic metasurface-based deflector deflecting the incident wave to the same direction at two selected wavelengths, which has circumvented the critical limitation of strong wavelength dependence in the planar metasurface-based devices caused by the resonant nature of the plasmonic structures. As a proof of concept demonstration, the designed dual-wavelength achromatic deflector has been fabricated, and characterized experimentally. The numerical simulations, theoretical predictions, and experimental results agree very well with each other, demonstrating the property of independently manipulating the phase profiles at two wavelengths. Furthermore, another unique feature of the designed metasurface is that it can independently tailor both the phase and amplitude profiles at two wavelengths. This property has been numerically validated by engineering a metasurface-based device to simultaneously generate two diffraction orders at two desired wavelengths. PMID:27659800

  9. Reliability and Validity of Field-Based Tests to Assess Upper-Body Muscular Strength in Children Aged 6-12 Years.

    PubMed

    Fernandez Santos, Jorge R; Ruiz, Jonatan R; Gonzalez-Montesinos, Jose Luis; Castro-Piñero, Jose

    2016-05-01

    The aim of this study was to analyze the reliability and the validity of the handgrip, basketball throw and pushups tests in children aged 6-12 years. One hundred and eighty healthy children (82 girls) agreed to participate in this study. All the upper body muscular fitness tests were performed twice (7 days apart) whereas the 1 repetition maximum (1RM) bench press test was performed 2 days after the first session of testing. All the tests showed a high reproducibility (ICC > 0.9) except the push-ups test (intertrial difference = 0.77 ± 2.38, p < .001 and the percentage error = 9%). The handgrip test showed the highest association with 1RM bench press test (r = .79, p < .01; R2 = .621). In conclusion the handgrip and basketball throw tests are shown as reliable and valid tests to assess upper body muscular strength in children. More studies are needed to assess the validity and the reliability of the upper body muscular endurance tests in children.

  10. Beam quality and wavelength limitation in visible and UV FEL oscillations

    SciTech Connect

    Tomimasu, T.

    1995-12-31

    The FELI linac beam has succeeded in visible-FEL oscillation on the third harmonics at 0.64 {mu}m using a 3-m undulator and a 6.72-m optical cavity with two Au-coated mirrors in Feb. 28, 1995. The beam is a 68-MeV, 40-A electron beam with a normalized emittance of 26 {pi}mm{center_dot}mrad and a relative energy spread of 1%. In 1993, an ultraviolet (UV) FEL oscillation was already achieved on the third harmonics at 0.37{mu} m using a 46-MeV, 130-A electron beam with a normalized emittance of 3{pi}mm{center_dot}mrad and a relative energy spread of 0.24% from the APEX L-band linac with an rf photocathode electron gun. However, we are now trying to achieve an FEL oscillation in the UV range using the FELI linac with the thermionic gun because of long-life, easy-operation, and low-cost of the thermionic gun, as the FELI ring with 9.8-m long straight sections capable of storing a long lived 1-A beam is in the design stage. Recent experimental and theoretical results on relations between beam quality and short wavelength FEL oscillations have been also reviewed and wavelength limitations due to normalized emittance and relative energy spread are discussed.

  11. BLAST05: POWER SPECTRA OF BRIGHT GALACTIC CIRRUS AT SUBMILLIMETER WAVELENGTHS

    SciTech Connect

    Roy, Arabindo; Martin, Peter G.; Netterfield, Calvin B.; Ade, Peter A. R.; Griffin, Matthew; Hargrave, Peter C.; Mauskopf, Philip; Bock, James J.; Chapin, Edward L.; Halpern, Mark; Marsden, Gaelen; Devlin, Mark J.; Dicker, Simon R.; Klein, Jeff; Rex, Marie; Gundersen, Joshua O.; Hughes, David H.; Miville-Deschenes, Marc-Antoine; Olmi, Luca; Patanchon, Guillaume

    2010-01-10

    We report multi-wavelength power spectra of diffuse Galactic dust emission from Balloon-borne Large Aperture Submillimeter Telescope observations at 250, 350, and 500 mum in Galactic plane fields in Cygnus X and Aquila. These submillimeter power spectra statistically quantify the self-similar structure observable over a broad range of scales and can be used to assess the cirrus noise which limits the detection of faint point sources. The advent of submillimeter surveys with the Herschel Space Observatory makes the wavelength dependence a matter of interest. We show that the observed relative amplitudes of the power spectra can be related through a spectral energy distribution (SED). Fitting a simple modified black body to this SED, we find the dust temperature in Cygnus X to be 19.8 +- 1.5 K and in the Aquila region 16.8 +- 0.8 K. Our empirical estimates provide important new insight into the substantial cirrus noise that will be encountered in forthcoming observations.

  12. Q-switching in a Cr{sup 3+}:Yb{sup 3+}:Ho{sup 3+}:YSGG crystal laser based on the {sup 5}I{sub 6} - {sup 5}I{sub 7} ({lambda}=2.92{mu}m) transition

    SciTech Connect

    Zavartsev, Yu D; Zagumennyi, A I; Kulevskii, L A; Lukashev, A V; Pashinin, Pavel P; Studenikin, P A; Shcherbakov, Ivan A; Umyskov, A F

    1999-04-30

    An investigation was made of the generation of giant pulses in a new yttrium scandium gallium garnet laser crystal doped with holmium (Cr{sup 3+}:Yb{sup 3+}:Ho{sup 3+}:YSGG) operating on the basis of the self-terminating {sup 5}I{sub 6} - {sup 5}I{sub 7} transition. Q-switching was performed by an electro-optical lithium niobate switch, a passive switch based on an epitaxial film of indium arsenide on a gallium arsenide substrate, or a passive switch consisting of water. The 2.92 {mu}m wavelength dominated giant pulse generation, whereas under free-running conditions the radiation was discretely tunable in the range 2.84 -3.05 {mu}m. Depending on the Q-switching method, pulses of 60 - 160 ns duration were generated and the pulse energy was {approx}20 mJ. The second and fourth harmonics of the holmium laser radiation were generated and the efficiency of each frequency-multiplication stage was {approx}20%. (lasers)

  13. THE EVOLUTION OF SOLAR FLUX FROM 0.1 nm TO 160 {mu}m: QUANTITATIVE ESTIMATES FOR PLANETARY STUDIES

    SciTech Connect

    Claire, Mark W.; Sheets, John; Meadows, Victoria S.; Cohen, Martin; Ribas, Ignasi; Catling, David C.

    2012-09-20

    Understanding changes in the solar flux over geologic time is vital for understanding the evolution of planetary atmospheres because it affects atmospheric escape and chemistry, as well as climate. We describe a numerical parameterization for wavelength-dependent changes to the non-attenuated solar flux appropriate for most times and places in the solar system. We combine data from the Sun and solar analogs to estimate enhanced UV and X-ray fluxes for the young Sun and use standard solar models to estimate changing visible and infrared fluxes. The parameterization, a series of multipliers relative to the modern top of the atmosphere flux at Earth, is valid from 0.1 nm through the infrared, and from 0.6 Gyr through 6.7 Gyr, and is extended from the solar zero-age main sequence to 8.0 Gyr subject to additional uncertainties. The parameterization is applied to a representative modern day flux, providing quantitative estimates of the wavelength dependence of solar flux for paleodates relevant to the evolution of atmospheres in the solar system (or around other G-type stars). We validate the code by Monte Carlo analysis of uncertainties in stellar age and flux, and with comparisons to the solar proxies {kappa}{sup 1} Cet and EK Dra. The model is applied to the computation of photolysis rates on the Archean Earth.

  14. Two wavelength satellite laser ranging using SPAD

    NASA Technical Reports Server (NTRS)

    Prochazka, Ivan; Hamal, Karel; Jelinkova, Helena; Kirchner, Georg; Koidl, F.

    1993-01-01

    When ranging to satellites with lasers, there are several principal contributions to the error budget: from the laser ranging system on the ground, from the satellite retroarray geometry, and from the atmosphere. Using a single wavelength, we have routinely achieved a ranging precision of 8 millimeters when ranging to the ERS-1 and Starlette satellites. The systematic error of the atmosphere, assuming the existing dispersion models, is expected to be of the order of 1 cm. Multiple wavelengths ranging might contribute to the refinement of the existing models. Taking into account the energy balance, the existing picosecond lasers and the existing receiver and detection technology, several pairs or multiple wavelengths may be considered. To be able to improve the atmospheric models to the subcentimeter accuracy level, the differential time interval (DTI) has to be determined within a few picoseconds depending on the selected wavelength pair. There exist several projects based on picosecond lasers as transmitters and on two types of detection techniques: one is based on photodetectors, like photomultipliers or photodiodes connected to the time interval meters. Another technique is based on the use of a streak camera as an echo signal detector, temporal analyzer, and time interval vernier. The temporal analysis at a single wavelength using the streak camera showed the complexity of the problem.

  15. Plasmonic All-Optical Tunable Wavelength Shifter

    SciTech Connect

    Flugel, B.; Macararenhas, A.; Snoke, D. W.; Pfeiffer, L. N.; West, K.

    2007-12-01

    At present, wavelength-division-multiplexed fibre lines routinely operate at 10 Gbit s{sup -1} per channel. The transition from static-path networks to true all-optical networks encompassing many nodes, in which channels are added/dropped and efficiently reassigned, will require improved tools for all-optical wavelength shifting. Specifically, one must be able to shift the carrier wavelength (frequency) of an optical data signal over tens of nanometres (a THz range) without the bottleneck of electrical conversion. Popular approaches to this problem make use of the nonlinear interaction between two wavelengths within a semiconductor optical amplifier whereas more novel methods invoke terahertz-frequency electro-optic modulation and polaritons. Here we outline the principles and demonstrate the use of optically excited plasmons as a tunable frequency source that can be mixed with a laser frequency through Raman scattering. The scheme is all-optical and enables dynamical control of the output carrier wavelength simply by varying the power of a control laser.

  16. Retrofit Weight-Loss Outcomes at 6, 12, and 24 Months and Characteristics of 12-Month High Performers: A Retrospective Analysis

    PubMed Central

    Hanson, Nicholas Buck; Kachin, Kevin; Berger, Jan

    2016-01-01

    Background Obesity is the leading cause of preventable death costing the health care system billions of dollars. Combining self-monitoring technology with personalized behavior change strategies results in clinically significant weight loss. However, there is a lack of real-world outcomes in commercial weight-loss program research. Objective Retrofit is a personalized weight management and disease-prevention solution. This study aimed to report Retrofit’s weight-loss outcomes at 6, 12, and 24 months and characterize behaviors, age, and sex of high-performing participants who achieved weight loss of 10% or greater at 12 months. Methods A retrospective analysis was performed from 2011 to 2014 using 2720 participants enrolled in a Retrofit weight-loss program. Participants had a starting body mass index (BMI) of >25 kg/m² and were at least 18 years of age. Weight measurements were assessed at 6, 12, and 24 months in the program to evaluate change in body weight, BMI, and percentage of participants who achieved 5% or greater weight loss. A secondary analysis characterized high-performing participants who lost ≥10% of their starting weight (n=238). Characterized behaviors were evaluated, including self-monitoring through weigh-ins, number of days wearing an activity tracker, daily step count average, and engagement through coaching conversations via Web-based messages, and number of coaching sessions attended. Results Average weight loss at 6 months was −5.55% for male and −4.86% for female participants. Male and female participants had an average weight loss of −6.28% and −5.37% at 12 months, respectively. Average weight loss at 24 months was −5.03% and −3.15% for males and females, respectively. Behaviors of high-performing participants were assessed at 12 months. Number of weigh-ins were greater in high-performing male (197.3 times vs 165.4 times, P=.001) and female participants (222 times vs 167 times, P<.001) compared with remaining participants

  17. On the Relative Importance of Convection and Temperature on the Behavior of the Ionosphere in North American during January 6-12, 1997

    NASA Technical Reports Server (NTRS)

    Richards, P. G.; Buonsanto, M. J.; Reinisch, B. W.; Holt, J.; Fennelly, J. A.; Scali, J. L.; Comfort, R. H.; Germany, G. A.; Spann, J.; Brittnacher, M.

    1999-01-01

    Measurements from a network of digisondes and an incoherent scatter radar In Eastern North American For January 6-12, 1997 have been compared with the Field Line Interhemispheric Plasma (FLIP) model which now includes the effects of electric field convective. With the exception of Bermuda, the model reproduces the daytime electron density very well most of the time. As is typical behavior for winter solar minimum on magnetically undisturbed nights, the measurements at Millstone Hill show high electron temperatures before midnight followed by a rapid decay, which is accompanied by a pronounced density enhancement in the early morning hours. The FLIP model reproduces the nighttime density enhancement well, provided the model is constrained to follow the topside electron temperature and the flux tube is full. Similar density enhancements are seen at Goose Bay, Wallops Island and Bermuda. However, the peak height variation and auroral images indicate the density enhancements at Goose Bay are most likely due to particle precipitation. Contrary to previously published work we find that the nighttime density variation at Millstone Hill is driven by the temperature behavior and not the other way around. Thus, in both the data and model, the overall nighttime density is lowered and the enhancement does not occur if the temperature remains high all night. Our calculations show that convections of plasma from higher magnetic latitudes does not cause the observed density maximum but it may enhance the density maximum if over-full flux tubes are convected over the station. On the other had, convection of flux tubes with high temperatures and depleted densities may prevent the density maximum from occurring. Despite the success in modeling the nighttime density enhancements, there remain two unresolved problems. First, the measured density decays much faster than the modeled density near sunset at Millstone Hill and Goose Bay though not at lower latitude stations. Second, we

  18. High-performance 1.55 {mu}m low-temperature-grown GaAs resonant-cavity-enhanced photodetector

    SciTech Connect

    Han, Q.; Niu, Z. C.; Peng, L. H.; Ni, H. Q.; Yang, X. H.; Du, Y.; Zhao, H.; Wu, R. H.; Wang, Q. M.

    2006-09-25

    A 1.55 {mu}m low-temperature-grown GaAs (LT-GaAs) photodetector with a resonant-cavityenhanced structure was designed and fabricated. A LT-GaAs layer grown at 200 deg. C was used as the absorption layer. Twenty- and fifteen-pair GaAs/AlAs-distributed Bragg reflectors were grown as the bottom and top mirrors. A responsivity of 7.1 mA/W with a full width at half maximum of 4 nm was obtained at 1.61 {mu}m. The dark current densities are 1.28x10{sup -7} A/cm{sup 2} at the bias of 0 V and 3.5x10{sup -5} A/cm{sup 2} at the reverse bias of 4.0 V. The transient response measurement showed that the photocarrier lifetime in LT-GaAs is 220 fs.

  19. Nonlinear frequency up-conversion of femtosecond pulses from an erbium fibre laser to the range of 0.8 - 1 {mu}m in silica fibres

    SciTech Connect

    Anashkina, E A; Andrianov, A V; Kim, A V

    2013-03-31

    We consider different mechanisms of nonlinear frequency up-conversion of femtosecond pulses emitted by an erbium fibre system ({lambda} = 1.5 {mu}m) to the range of 0.8 - 1.2 {mu}m in nonlinear silica fibres. The generation efficiency and the centre frequencies of dispersive waves are found as functions of the parameters of the fibre and the input pulse. Simple analytical estimates are obtained for the spectral distribution of the intensity and the frequency shift of a wave packet in the region of normal dispersion during the emission of a high-order soliton under phase matching conditions. In the geometrical optics approximation the frequency shifts are estimated in the interaction of dispersive waves with solitons in various regimes. (extreme light fields and their applications)

  20. Uncooled 2.5 Gb/s operation of 1.3 mum GaInNAs DQW lasers over a wide temperature range.

    PubMed

    Wei, Yongqiang; Gustavsson, Johan S; Sadeghi, Mahdad; Wang, Shumin; Larsson, Anders; Savolainen, Pekka; Melanen, Petri; Sipilä, Pekko

    2006-04-01

    Ridge waveguide 1.3 mum GaInNAs lasers were fabricated from high quality double quantum well material grown by molecular beam epitaxy. Short cavity (250 mum) lasers have low threshold currents and small temperature dependencies of threshold current and slope efficiency, with a characteristic temperature of the threshold current as high as 200 K. The temperature stability allows for uncooled 2.5 Gb/s operation up to temperatures as high as 110 degrees C with a constant modulation voltage and only the bias current adjusted for constant average output power. Under these conditions, an extinction ratio larger than 6 dB and a spectral rms-width smaller than 2 nm are obtained. PMID:19516408

  1. Cryogenic Amplifier Based Receivers at Submillimeter Wavelengths

    NASA Technical Reports Server (NTRS)

    Chattopadhyay, Goutam; Reck, Theodore and; Schlecht, Erich; Lin, Robert; Deal, William

    2012-01-01

    The operating frequency of InP high electron mobility transistor (HEMT) based amplifiers has moved well in the submillimeter-wave frequencies over the last couple of years. Working amplifiers with usable gain in waveguide packages has been reported beyond 700 GHz. When cooled cryogenically, they have shown substantial improvement in their noise temperature. This has opened up the real possibility of cryogenic amplifier based heterodyne receivers at submillimeter wavelengths for ground-based, air-borne, and space-based instruments for astrophysics, planetary, and Earth science applications. This paper provides an overview of the science applications at submillimeter wavelengths that will benefit from this technology. It also describes the current state of the InP HEMT based cryogenic amplifier receivers at submillimeter wavelengths.

  2. Integrated nonlinear interferometer with wavelength multicasting functionality.

    PubMed

    Yang, Weili; Yu, Yu; Zhang, Xinliang

    2016-08-01

    Nonlinear interference based on four wave mixing (FWM) is extremely attractive due to its phase sensitivity. On the other hand, wavelength multicasting, which supports data point-to-multipoint connections, is a key functionality to increase the network efficiency and simplify the transmitter and receiver in the wavelength-division multiplexing systems. We propose and experimentally demonstrate a nonlinear interferometer with wavelength multicasting functionality based on single-stage FWM in an integrated silicon waveguide. With a three-pump and dual-signal input, four phase sensitive idlers are obtained at the interferometer output. For a proof-of-concept application, we further theoretically demonstrate the multicasting logic exclusive-OR (XOR) gate for both intensity and phase modulated signals. The proposed scheme would be potentially applied in various on-chip applications for future optical communication system. PMID:27505786

  3. Wavelength agile holmium-doped fiber laser

    NASA Astrophysics Data System (ADS)

    Simakov, N.; Daniel, J. M. O.; Ward, J.; Clarkson, W. A.; Hemming, A.; Haub, J.

    2016-03-01

    For the first time, an electronically-controlled, wavelength-agile tuneable holmium-doped fibre laser is presented. A narrow-band acousto-optic tuneable filter was characterized and used as the wavelength selective element to avoid any inertial effects associated with opto-mechanical tuning mechanisms. We demonstrate operation over a 90 nm wavelength range spanning 2040 - 2130 nm. The laser produced >150 mW over this entire range with a signal-to-noise ratio of >45 dB and line-width of ~0.16 nm. Switching times of ~35 μs and sweep rates of up to 9 nm/ms were also demonstrated.

  4. Device for wavelength-selective imaging

    SciTech Connect

    Frangioni, John V.

    2010-09-14

    An imaging device captures both a visible light image and a diagnostic image, the diagnostic image corresponding to emissions from an imaging medium within the object. The visible light image (which may be color or grayscale) and the diagnostic image may be superimposed to display regions of diagnostic significance within a visible light image. A number of imaging media may be used according to an intended application for the imaging device, and an imaging medium may have wavelengths above, below, or within the visible light spectrum. The devices described herein may be advantageously packaged within a single integrated device or other solid state device, and/or employed in an integrated, single-camera medical imaging system, as well as many non-medical imaging systems that would benefit from simultaneous capture of visible-light wavelength images along with images at other wavelengths.

  5. Mechanisms and Methods for Selective Wavelength Filtering

    NASA Technical Reports Server (NTRS)

    Tuma, Margaret (Inventor); Brown, Thomas G. (Inventor); Gruhlke, Russell (Inventor)

    2007-01-01

    An optical filter includes a dielectric waveguide layer, supporting waveguide modes at specific wavelengths and receiving incident light, a corrugated film layer, composed of one of a metal and a semiconductor and positioned adjacent to a second surface of the waveguide layer and a sensor layer, wherein the sensor layer is capable of absorbing optical energy and generating a corresponding electrical signal. The metal film layer supports a plurality of plasmons, the plurality of plasmons producing a first field and is excited by a transverse mode of the waveguide modes at a wavelength interval. The first field penetrates the sensor layer and the sensor layer generates an electrical signal corresponding to an intensity of received incident light within the wavelength interval.

  6. Dynamic polarizabilities and magic wavelengths for dysprosium

    SciTech Connect

    Dzuba, V. A.; Flambaum, V. V.; Lev, Benjamin L.

    2011-03-15

    We theoretically study dynamic scalar polarizabilities of the ground and select long-lived excited states of dysprosium, a highly magnetic atom recently laser cooled and trapped. We demonstrate that there is a set of magic wavelengths of the unpolarized lattice laser field for each pair of states, which includes the ground state and one of these excited states. At these wavelengths, the energy shift due to laser field is the same for both states, which can be useful for resolved sideband cooling on narrow transitions and precision spectroscopy. We present an analytical formula that, near resonances, allows for the determination of approximate values of the magic wavelengths without calculating the dynamic polarizabilities of the excited states.

  7. CAN GROUND-BASED TELESCOPES DETECT THE OXYGEN 1.27 {mu}m ABSORPTION FEATURE AS A BIOMARKER IN EXOPLANETS?

    SciTech Connect

    Kawahara, Hajime; Matsuo, Taro; Takami, Michihiro; Fujii, Yuka; Kotani, Takayuki; Tamura, Motohide; Murakami, Naoshi; Guyon, Olivier

    2012-10-10

    The oxygen absorption line imprinted in the scattered light from Earth-like planets has been considered the most promising metabolic biomarker for exolife. We examine the feasibility of the detection of the 1.27 {mu}m oxygen band from habitable exoplanets, in particular, around late-type stars observed with a future instrument on a 30 m class ground-based telescope. We analyzed the night airglow around 1.27 {mu}m with the IRCS/echelle spectrometer on Subaru and found that the strong telluric emission from atmospheric oxygen molecules declines by an order of magnitude by midnight. By compiling nearby star catalogs combined with the sky background model, we estimate the detectability of the oxygen absorption band from an Earth twin, if it exists, around nearby stars. We find that the most dominant source of photon noise for the oxygen 1.27 {mu}m band detection comes from the night airglow if the contribution of the stellar point-spread function (PSF) halo is suppressed enough to detect the planet. We conclude that the future detectors, for which the detection contrast is limited by photon noise, can detect the oxygen 1.27 {mu}m absorption band of Earth twins for {approx}50 candidates of the late-type star. This paper demonstrates the importance of deploying a small inner working angle as an efficient coronagraph and extreme adaptive optics on extremely large telescopes, and clearly shows that doing so will enable the study of potentially habitable planets.

  8. 900-mW average power and tunability from a diode-pumped 2.94-{mu}m Er:YAG oscillator

    SciTech Connect

    Hamilton, C.E.; Beach, R.J.; Sutton, S.B.; Furu, L.; Krupke, W.F.

    1994-01-01

    In this paper, the authors report on a diode-side-pumped Er:YAG laser that generates over 500 mW of average power at 2.94 {mu}m, and tunes over a 6 nm range centered about the 2.94-{mu}m transition. Prior to the development of the laser, diode-pumped Er:YAG lasers have been end-pumped monolithic devices that deliver {approximately}200 mW of output at 2.94 {mu}m. Much of the difficulty in obtaining higher average power from Er:YAG stems from the unfavorable lifetimes of the upper and lower laser levels, the complex state dynamics, and a low stimulated emission cross section ({sigma} {approx} 3 {times} 10{sup {minus}20} cm{sup 2}). One of the most important dynamical processes in Er:YAG is cross relaxation between neighboring Er{sup 3+} ions in the {sup 4}I{sub 13/2} level. By recycling much of the {sup 4}I{sub 13/2} population (lower laser level) into {sup 4}I{sub 11/2} (upper laser level), the cross relaxation overcomes the unfavorable lifetimes of the two levels, allowing the population inversion to be sustained. It is this cross relaxation along with thermalization of the two laser levels that allows cw oscillation on the 2.94 {mu}m line to take place. The laser that they describe here is a quasi-cw device as the approach to obtaining higher average power and limited tunability relies on side pumping with a quasi-cw InGaAs laser diode array. In this way, a higher gain-length product is generated, which is necessary for extending the tuning range of the laser, and for overcoming the higher losses associated with a discreet-element resonator.

  9. THE COMPTON-THICK SEYFERT 2 NUCLEUS OF NGC 3281: TORUS CONSTRAINTS FROM THE 9.7 {mu}m SILICATE ABSORPTION

    SciTech Connect

    Sales, Dinalva A.; Pastoriza, M. G.; Riffel, R.; Winge, C.

    2011-09-01

    We present mid-infrared (mid-IR) spectra of the Compton-thick Seyfert 2 galaxy NGC 3281, obtained with the Thermal-Region Camera Spectrograph at the Gemini-South telescope. The spectra present a very deep silicate absorption at 9.7 {mu}m, and [S IV] 10.5 {mu}m and [Ne II] 12.7 {mu}m ionic lines, but no evidence of polycyclic aromatic hydrocarbon emission. We find that the nuclear optical extinction is in the range 24 mag {<=} A{sub V} {<=} 83 mag. A temperature T = 300 K was found for the blackbody dust continuum component of the unresolved 65 pc nucleus and the region at 130 pc SE, while the region at 130 pc NW reveals a colder temperature (200 K). We describe the nuclear spectrum of NGC 3281 using a clumpy torus model that suggests that the nucleus of this galaxy hosts a dusty toroidal structure. According to this model, the ratio between the inner and outer radius of the torus in NGC 3281 is R{sub 0}/R{sub d} = 20, with 14 clouds in the equatorial radius with optical depth of {tau}{sub V} = 40 mag. We would be looking in the direction of the torus equatorial radius (i = 60{sup 0}), which has outer radius of R{sub 0} {approx} 11 pc. The column density is N{sub H} {approx} 1.2 x 10{sup 24} cm{sup -2} and the iron K{alpha} equivalent width ({approx}0.5-1.2 keV) is used to check the torus geometry. Our findings indicate that the X-ray absorbing column density, which classifies NGC 3281 as a Compton-thick source, may also be responsible for the absorption at 9.7 {mu}m providing strong evidence that the silicate dust responsible for this absorption can be located in the active galactic nucleus torus.

  10. THE 3-5 {mu}m SPECTRUM OF NGC 1068 AT HIGH ANGULAR RESOLUTION: DISTRIBUTION OF EMISSION AND ABSORPTION FEATURES ACROSS THE NUCLEAR CONTINUUM SOURCE

    SciTech Connect

    Geballe, T. R.; Mason, R. E.; Rodriguez-Ardila, A.; Axon, D. J.

    2009-08-20

    We report moderate resolution 3-5 {mu}m spectroscopy of the nucleus of NGC 1068 obtained at 0.''3 (20 pc) resolution with the spectrograph slit aligned approximately along the ionization cones of the active galactic nucleus. The deconvolved full width at half-maximum of the nuclear continuum source in this direction is 0.''3. Four coronal lines of widely different excitations were detected; the intensity of each peaks near radio knot C, approximately 0.''3 north of the infrared continuum peak, where the radio jet changes direction. Together with the broadened line profiles observed near that location, this suggests that shock ionization is the dominant excitation mechanism of the coronal lines. The depth of the 3.4 {mu}m hydrocarbon absorption is maximum at and just south of the continuum peak, similar to the 10 {mu}m silicate absorption. That and the similar and rapid variations of the optical depths of both features across the nucleus suggest that substantial portions of both arise in a dusty environment just in front of the continuum source(s). A new and tighter limit is set on the column density of CO. Although clumpy models of the dust screen might explain the shallowness of the silicate feature, the presence of the 3.4 {mu}m feature and the absence of CO are strongly reminiscent of Galactic diffuse cloud environments and a consistent explanation for them and the observed silicate feature is found if all three phenomena occur in such an environment, existing as close as 10 pc to the central engine.

  11. THE CARNEGIE HUBBLE PROGRAM: THE LEAVITT LAW AT 3.6 AND 4.5 {mu}m IN THE MILKY WAY

    SciTech Connect

    Monson, Andrew J.; Freedman, Wendy L.; Madore, Barry F.; Persson, S. E.; Scowcroft, Victoria; Seibert, Mark; Rigby, Jane R. E-mail: wendy@obs.carnegiescience.edu E-mail: persson@obs.carnegiescience.edu E-mail: mseibert@obs.carnegiescience.edu

    2012-11-10

    The Carnegie Hubble Program (CHP) is designed to calibrate the extragalactic distance scale using data from the post-cryogenic era of the Spitzer Space Telescope. The ultimate goal of the CHP is a systematic improvement in the distance scale leading to a determination of the Hubble constant to within an accuracy of 2%. This paper focuses on the measurement and calibration of the Galactic Cepheid period-luminosity (PL, Leavitt) relation using the warm Spitzer/IRAC 1 and 2 bands at 3.6 and 4.5 {mu}m. We present photometric measurements covering the period range 4-70 days for 37 Galactic Cepheids. Data at 24 phase points were collected for each star. Three PL relations of the form M = a(log (P) - 1) + b are derived. The method adopted here takes the slope a to be -3.31, as determined from the Spitzer Large Magellanic Cloud (LMC) data of Scowcroft et al. Using the geometric Hubble Space Telescope guide-star distances to 10 Galactic Cepheids, we find a calibrated 3.6 {mu}m PL zero point of -5.80 {+-} 0.03. Together with our value for the LMC zero point, we determine a reddening-corrected distance modulus of 18.48 {+-} 0.04 mag to the LMC. The mid-IR period-color diagram and the [3.6]-[4.5] color variation with phase are interpreted in terms of CO absorption at 4.5 {mu}m. This situation compromises the use of the 4.5 {mu}m data for distance determinations.

  12. A MULTI-WAVELENGTH STUDY OF THE STAR-FORMING CORE AHEAD OF HH 80N

    SciTech Connect

    Masque, Josep M.; Estalella, Robert; Osorio, Mayra; Anglada, Guillem; Garay, Guido; Calvet, Nuria; Beltran, Maria T.

    2011-09-01

    We present observations of continuum emission in the mid-infrared to millimeter wavelength range, complemented with ammonia observations, of the dense core ahead of the radio Herbig-Haro (HH) object HH 80N, found in the GGD 27 region. The continuum emission in all the observed bands peaks at the same position, consistent with the presence of an embedded object, HH 80N-IRS1, within the core. The distribution of the Very Large Array ammonia emission is well correlated with that of the dust, suggesting that photochemical effects caused by the nearby HH object do not play an important role in shaping this particular molecular emission. In order to unveil the nature of HH 80N-IRS1, we analyzed the continuum data of this source, using self-consistent models of protostellar collapse. We find that a young protostar surrounded by a slowly rotating collapsing envelope of radius {approx}0.08 pc and 20 M{sub sun} plus a circumstellar disk of radius {approx}300 AU and 0.6 M{sub sun} provide a good fit to the observed spectral energy distribution and to the maps at 350 {mu}m, 1.2 mm, and 3.5 mm of HH 80N-IRS1. Besides, the Atacama Pathfinder Experiment and Plateau de Bure Interferometer continuum maps at 350 {mu}m and 3.5 mm, respectively, reveal additional clumps in the continuum emission. Given the modeling results and the observed morphology of the emission, we propose a scenario consisting of a central embedded Class 0 object, HH 80N-IRS1, with the rest of the material of the HH 80N core possibly undergoing fragmentation that may lead to the formation of several protostars.

  13. B-cell transcription factors Pax-5, Oct-2, BOB.1, Bcl-6, and MUM1 are useful markers for the diagnosis of nodular lymphocyte predominant Hodgkin lymphoma.

    PubMed

    Herbeck, Rosemarie; Teodorescu Brînzeu, D; Giubelan, Marioara; Lazăr, Elena; Dema, Alis; Ioniţă, Hortensia

    2011-01-01

    In some instances, the overlap in morphologic features and antigen expression between nodular lymphocyte predominant Hodgkin lymphoma (NLPHL) and classical Hodgkin lymphoma (cHL) can cause confusion in the diagnosis. In these cases, the transcription factors (TFs) B-cell specific activator protein (BSAP)/Pax-5, octamer binding protein-2 (Oct-2), B-lymphocyte-specific co-activator BOB.1/OBF.1, Bcl-6 protein and multiple myeloma-1/interferon regulatory factor-4 (MUM1/IRF-4) may aid in clarifying the diagnosis. Twenty-two cases of NLPHL were studied for the immunohistochemical expression of Pax-5, Oct-2, BOB.1, Bcl-6 protein and MUM1/IRF-4. Our results sustain the usefulness of the selected set of TFs to diagnose and distinguish NLPHL from cHL since Pax-5, Oct-2, BOB.1 and Bcl-6 are consistently expressed by lymphocyte predominant (LP) cells and reported by others to be often unexpressed in Hodgkin and Reed-Sternberg cells. By contrast, MUM1/IRF-4 protein scored negative in the majority of LP cells, but is reported to be expressed in almost all cases of cHL. Thus, although the expression of transcription factors is very heterogeneous, their simultaneous implementation for positive and differential diagnosis may be useful. PMID:21424034

  14. Variable wavelength selection devices: Physics and applications

    NASA Astrophysics Data System (ADS)

    Xianyu, Haiqing

    Variable wavelength selection (VWS) achieved by implementing tunability to wavelength discriminating devices has generated great interest in basic science, applied physics, and technology. This thesis focuses on the underlying physics and application of several novel wavelength discriminating devices. Holographical polymer dispersed liquid crystals (HPDLCs) are switchable volume gratings formed by exposing a photopolymerizable monomer and liquid crystal mixture to interfering monochromatic light beams. An HPDLCs wavelength discriminating ability along with its switchability, allow it to be utilized in VWS devices. A novel mode HPDLC, total internal reflection (TIR) HPDLC, has been developed as a wavelength selective filter. The grating planes in this device are tilted so that the diffracted light experiences total internal reflection at the glass-air interface and is trapped in the cell until it eventually escapes from an edge. A VWS device is demonstrated by stacking TIR HPDLCs operating at different wavelengths. Converging or diverging recording beams are employed to fabricate chirped reflection HPDLCs with a pitch gradient along the designated direction, creating chirped switchable reflection gratings (CSRGs). A pixelated version of the CSRG is developed herein, and a dynamic spectral equalizer is presented by combining the pixelated CSRG with a prism (for wavelength discrimination). A switchable circular to point converter (SCPC), which enables the random selection of the wavelength bands divided by the Fabry-Perot interferometer utilizing the controllable beam steering capability of transmission HPDLCs, is demonstrated. A random optical cross-switch (TIROL) can be created by integrating a Fabry-Perot interferometer with a stack of SCPC units. The in-plane electric field generated by the interdigitated electrodes is utilized to elongate the helical pitch of a cholesteric liquid crystal and thereby induces a red shift of the transmission reflection peak

  15. Undulators for short wavelength FEL amplifiers

    SciTech Connect

    Schlueter, R.

    1994-08-01

    Issues critical to the design of undulators for use in short wavelength FEL amplifiers, such as attainable on-axis field strength, device compactness, field quality, required magnetic gap, and strong focusing schemes, are discussed. The relative strength of various undulator technologies, including pure permanent magnet, hybrid, warm electromagnetic, pulsed, and superconducting electromagnetic devices in both helical and planar configurations are reviewed. Favored design options for proposed short wavelength FELs, such as the Linac Coherent Light Source at SLAC and the DUV Free-Electron Laser at BNL, are presented.

  16. Effects of Laser Wavelength on Ablator Testing

    NASA Technical Reports Server (NTRS)

    White, Susan M.

    2014-01-01

    Wavelength-dependent or spectral radiation effects are potentially significant for thermal protection materials. NASA atmospheric entry simulations include trajectories with significant levels of shock layer radiation which is concentrated in narrow spectral lines. Tests using two different high powered lasers, the 10.6 micron LHMEL I CO2 laser and the near-infrared 1.07 micron fiber laser, on low density ablative thermal protection materials offer a unique opportunity to evaluate spectral effects. Test results indicated that the laser wavelength can impact the thermal response of an ablative material, in terms of bond-line temperatures, penetration times, mass losses, and char layer thicknesses.

  17. Miniature integrated-optical wavelength analyzer chip

    NASA Astrophysics Data System (ADS)

    Kunz, R. E.; Dübendorfer, J.

    1995-11-01

    A novel integrated-optical chip suitable for realizing compact miniature wavelength analyzers with high linear dispersion is presented. The chip performs the complete task of converting the spectrum of an input beam into a corresponding spatial irradiance distribution without the need for an imaging function. We demonstrate the feasibility of this approach experimentally by monitoring the changes in the mode spectrum of a laser diode on varying its case temperature. Comparing the results with simultaneous measurements by a commercial spectrometer yielded a rms wavelength deviation of 0.01 nm.

  18. Modulation compression for short wavelength harmonic generation

    SciTech Connect

    Qiang, J.

    2010-01-11

    Laser modulator is used to seed free electron lasers. In this paper, we propose a scheme to compress the initial laser modulation in the longitudinal phase space by using two opposite sign bunch compressors and two opposite sign energy chirpers. This scheme could potentially reduce the initial modulation wavelength by a factor of C and increase the energy modulation amplitude by a factor of C, where C is the compression factor of the first bunch compressor. Such a compressed energy modulation can be directly used to generate short wavelength current modulation with a large bunching factor.

  19. An economic Fabry-Perot wavelength reference

    NASA Astrophysics Data System (ADS)

    Fżrész, Gábor; Glenday, Alex; Latham, Christian

    2014-07-01

    Precision radial velocity (PRV) measurements are key in studying exoplanets, and so are wavelength calibrators in PRV instruments. ThAr lamps offer an affordable but somewhat limited solution for the visible passband. Laser frequency combs are ideal calibrators, except the (still) narrow wavelength coverage and large price tag. White light Fabry-Perot (FP) calibrators offer frequency-comb like properties in a more affordable and less complicated package1. Using a commercial solid FP etalon and off-the shelf components we have constructed an economic FP calibrator suitable for observatories on a smaller budget.

  20. Dual-wavelength erbium-doped fiber laser with tunable wavelength spacing using a twin core fiber-based filter

    NASA Astrophysics Data System (ADS)

    Yin, Guolu; Lou, Shuqin; Wang, Xin; Han, Bolin

    2014-05-01

    A dual-wavelength erbium-doped fiber laser with tunable wavelength spacing was proposed and experimentally demonstrated by using a twin core fiber (TCF)-based filter. Benefiting from the polarization dependence of the TCF-based filter, the laser operated in dual-wavelength oscillation with two orthogonal polarization states. By adjusting the polarization controller, the wavelength spacing was tuned from 0.1 nm to 1.2 nm without shifting the centre position of the two wavelengths. By stretching the TCF, the two wavelengths were simultaneously tuned with fixed wavelength spacing. Such a dual-wavelength fiber laser could find applications in optical fiber sensors and microwave photonics generation.

  1. Discrete wavelength-locked external cavity laser

    NASA Technical Reports Server (NTRS)

    Pilgrim, Jeffrey S. (Inventor); Silver, Joel A. (Inventor)

    2005-01-01

    An external cavity laser (and method of generating laser light) comprising: a laser light source; means for collimating light output by the laser light source; a diffraction grating receiving collimated light; a cavity feedback mirror reflecting light received from the diffraction grating back to the diffraction grating; and means for reliably tuning the external cavity laser to discrete wavelengths.

  2. Superiority of half-wavelength helicon antennae

    NASA Astrophysics Data System (ADS)

    Porte, L.; Yun, S. M.; Arnush, D.; Chen, F. F.

    2003-05-01

    Plasma densities produced by half- and full-wavelength (HW and FW) helical antennae in helicon discharges are compared. It is found that HW antennae are more efficient than FW ones in producing plasma downstream from the antenna. The measured wave amplitudes and the apparent importance of downstream ionization do not agree with computations.

  3. Wavelength control of visible light laser diodes

    NASA Astrophysics Data System (ADS)

    Goto, N.; Fujii, T.; Nemoto, K.; Suzuki, H.; Nakagawa, K.; Otsu, M.

    1990-04-01

    Wavelength control of visible light laser diodes was studied. By combining an interferometer and a diffraction grating, it became possible to control the wavelength of continuous oscillation in the range of 664 to 673nm, the frequency fine control range being 2GHz. And the spectral linewidth was narrowed to about 44kHz (10 exp minus 7 nm). With the use of a collimator lens, the beam expansion was narrowed to 2mrad. It was confirmed that the pulse output of continuous oscillation visible light laser diodes can be amplified by the YAG laser excitation dye laser. In the case of pulse oscillation, oscillation of 1GHz spectral width was obtained at the wavelength of 0.8 micro m by using an injection synchronization method. In the injection synchronization method, other laser beam is injected in an oscillator and a superior laser beam of synchronized components alone is obtained. As the wavelength control method is now stabilized and satisfies the conditions of narrow band, it has the prospect to be applied to the laser uranium enrichment technology.

  4. Resolving the Moth at Millimeter Wavelengths

    NASA Astrophysics Data System (ADS)

    Ricarte, Angelo; Moldvai, Noel; Hughes, A. Meredith; Duchêne, Gaspard; Williams, Jonathan P.; Andrews, Sean M.; Wilner, David J.

    2013-09-01

    HD 61005, also known as "The Moth," is one of only a handful of debris disks that exhibit swept-back "wings" thought to be caused by interaction with the ambient interstellar medium (ISM). We present 1.3 mm Submillimeter Array observations of the debris disk around HD 61005 at a spatial resolution of 1.''9 that resolve the emission from large grains for the first time. The disk exhibits a double-peaked morphology at millimeter wavelengths, consistent with an optically thin ring viewed close to edge-on. To investigate the disk structure and the properties of the dust grains we simultaneously model the spatially resolved 1.3 mm visibilities and the unresolved spectral energy distribution (SED). The temperatures indicated by the SED are consistent with expected temperatures for grains close to the blowout size located at radii commensurate with the millimeter and scattered light data. We also perform a visibility-domain analysis of the spatial distribution of millimeter-wavelength flux, incorporating constraints on the disk geometry from scattered light imaging, and find suggestive evidence of wavelength-dependent structure. The millimeter-wavelength emission apparently originates predominantly from the thin ring component rather than tracing the "wings" observed in scattered light. The implied segregation of large dust grains in the ring is consistent with an ISM-driven origin for the scattered light wings.

  5. RESOLVING THE MOTH AT MILLIMETER WAVELENGTHS

    SciTech Connect

    Ricarte, Angelo; Moldvai, Noel; Hughes, A. Meredith; Duchene, Gaspard; Williams, Jonathan P.; Andrews, Sean M.; Wilner, David J.

    2013-09-01

    HD 61005, also known as ''The Moth'', is one of only a handful of debris disks that exhibit swept-back ''wings'' thought to be caused by interaction with the ambient interstellar medium (ISM). We present 1.3 mm Submillimeter Array observations of the debris disk around HD 61005 at a spatial resolution of 1.''9 that resolve the emission from large grains for the first time. The disk exhibits a double-peaked morphology at millimeter wavelengths, consistent with an optically thin ring viewed close to edge-on. To investigate the disk structure and the properties of the dust grains we simultaneously model the spatially resolved 1.3 mm visibilities and the unresolved spectral energy distribution (SED). The temperatures indicated by the SED are consistent with expected temperatures for grains close to the blowout size located at radii commensurate with the millimeter and scattered light data. We also perform a visibility-domain analysis of the spatial distribution of millimeter-wavelength flux, incorporating constraints on the disk geometry from scattered light imaging, and find suggestive evidence of wavelength-dependent structure. The millimeter-wavelength emission apparently originates predominantly from the thin ring component rather than tracing the ''wings'' observed in scattered light. The implied segregation of large dust grains in the ring is consistent with an ISM-driven origin for the scattered light wings.

  6. SDIO long wavelength infrared detector requirements

    NASA Technical Reports Server (NTRS)

    Duston, Dwight

    1990-01-01

    The Strategic Defense Initiative Organization (SDIO) has a significant requirement for infrared sensors for surveillance, tracking and discrimination of objects in space. Projected SDIO needs cover the range from short wavelengths out to 30 microns. Large arrays are required, and producibility and cost are major factors. The SDIO is pursuing several approaches including innovative concepts based on semiconductors and superconductors.

  7. Laser wavelength comparison by high resolution interferometry.

    PubMed

    Layer, H P; Deslattes, R D; Schweitzer, W G

    1976-03-01

    High resolution interferometry has been used to determine the wavelength ratio between two molecularly stabilized He-Ne lasers, one locked to a methane absorption at 3.39 microm and the other locked to the k peak of (129)I(2) at 633 nm. An optical beat frequency technique gave fractional orders while a microwave sideband method yielded the integer parts. Conventional (third derivative) peak seeking servoes stabilized both laser and cavity lengths. Reproducibility of the electronic control system and optics was a few parts in 10(12), while systematic errors associated with curvature of the cavity mirrors limited the accuracy of the wavelength ratio measurement to 2 parts in 10(10). The measured wavelength ratio of the methane stabilized He-Ne laser at 3.39 microm [P(7) line, nu(3) band] to the (129)I(2) (k peak) stabilized He-Ne laser at 633 nm was 5.359 049 260 6 (0.000 2 ppm). This ratio agrees with that calculated from the (lower accuracy) results of earlier wavelength measurements made relative to the (86)Kr standard. Its higher accuracy thus permits a provisional extension of the frequency scale based on the cesium oscillator into the visible spectrum.

  8. The wavelength dependence of Triton's light curve

    NASA Technical Reports Server (NTRS)

    Hillier, J.; Veverka, J.; Helfenstein, P.; Mcewen, A.

    1991-01-01

    Using Voyager observations, it is demonstrated that Triton's orbital light curve is strongly wavelength-dependent, a characteristic which readily explains some of the apparent discrepancies among pre-Voyager telescopic measurements. Specifically, a light curve amplitude (peak to peak) is found that decreases systematically with increasing wavelength from about 0.08 magnitude (peak to peak) near 200 nm to less than 0.02 magnitude near 1000 nm. Peak brightness occurs near 90 deg orbital longitude (leading hemisphere). The brightness variation across this hemisphere is close to sinusoidal; the variation across the darker hemisphere is more complex. The decrease in light curve amplitude with increasing wavelength appears to be due to a decrease in contrast among surface markings, rather than to atmospheric obscuration. The model also explains the observed decrease in the amplitude of Triton's light curve at visible wavelengths over the past decade, a decrease related to the current migration of the subsolar latitude toward the south pole; it is predicted that this trend will continue into the 1990s.

  9. Two-wavelength spatial-heterodyne holography

    DOEpatents

    Hanson, Gregory R.; Bingham, Philip R.; Simpson, John T.; Karnowski, Thomas P.; Voelkl, Edgar

    2007-12-25

    Systems and methods are described for obtaining two-wavelength differential-phase holograms. A method includes determining a difference between a filtered analyzed recorded first spatially heterodyne hologram phase and a filtered analyzed recorded second spatially-heterodyned hologram phase.

  10. Devices for wavelength switching in optical networks

    SciTech Connect

    d`Alessandro, A.; Baran, J.E.; Smith, D.A.

    1994-12-31

    Wavelength routing crossconnects are considered the core of WDM optical networks. They consist of optical switches independently rearrangeable for each wavelength channel and for any input-output configuration so that any path can be chosen almost arbitrarily by the network users. In general the implementation of the wavelength routing function requires complex switch arrays. Very simple wavelength-selection crossconnects can be realized by using acousto-optic switches (AOS), because of their unique ability of processing several optical signals simultaneously and their low driving power consumption, less than 10 mW/channel. AOS`s can be considered a particular evolution of acousto-optical tunable filters, whose integrated optic version on lithium niobate has been developed in several research institutions around the world in the past decade. This paper reviews the last accomplishments of AOS`s, whose specifications are directly tied with optical network requirements, the foremost challenge being a strong suppression of crosstalk. Dilated AOS`s can reduce interport crosstalk to below {minus}30 dB and apodization of acousto-optic interaction can reduce interchannel crosstalk to below {minus}15 dB during multiwavelength operation.

  11. Electricity and short wavelength radiation generator

    DOEpatents

    George, E.V.

    1985-08-26

    Methods and associated apparati for use of collisions of high energy atoms and ions of He, Ne, or Ar with themselves or with high energy neutrons to produce short wavelength radiation (lambda approx. = 840-1300 A) that may be utilized to produce cathode-anode currents or photovoltaic currents.

  12. Self Calibration of a 2-wavelength Pyrometer

    NASA Technical Reports Server (NTRS)

    Ng, Daniel

    1998-01-01

    Pyrometers require calibrations to determine their instrument constants before they can be used in remote temperature measurements. These constants reflect the combined effects of detector response, the transmissivities of intervening optical media (windows and gases) and the emissivity of the measured surface. We describe here the principal and the demonstration of self calibrating 2-wavelength pyrometer.

  13. OPTICAL PROPERTIES OF IRON SILICATES IN THE INFRARED TO MILLIMETER AS A FUNCTION OF WAVELENGTH AND TEMPERATURE

    SciTech Connect

    Richey, C. R.; Kinzer, R. E.; Cataldo, G.; Wollack, E. J.; Nuth, J. A.; Benford, D. J.; Silverberg, R. F.; Rinehart, S. A.

    2013-06-10

    The Optical Properties of Astronomical Silicates with Infrared Techniques program utilizes multiple instruments to provide spectral data over a wide range of temperatures and wavelengths. Experimental methods include Vector Network Analyzer and Fourier transform spectroscopy transmission, and reflection/scattering measurements. From this data, we can determine the optical parameters for the index of refraction, n, and the absorption coefficient, k. The analysis of the laboratory transmittance data for each sample type is based upon different mathematical models, which are applied to each data set according to their degree of coherence. Presented here are results from iron silicate dust grain analogs, in several sample preparations and at temperatures ranging from 5 to 300 K, across the infrared and millimeter portion of the spectrum (from 2.5 to 10,000 {mu}m or 4000 to 1 cm{sup -1}).

  14. Molecular beam epitaxy of n-Zn(Mg)O as a low-damping plasmonic material at telecommunication wavelengths

    SciTech Connect

    Sadofev, Sergey; Kalusniak, Sascha; Schaefer, Peter; Henneberger, Fritz

    2013-05-06

    We demonstrate that Zn(Mg)O:Ga layers can be grown by molecular beam epitaxy in a two-dimensional mode with high structural perfection up to Ga mole fractions of about 6.5%. The doping efficiency is practically 100% so that free-carrier concentrations of almost 10{sup 21} cm{sup -3} can be realized providing a zero-crossover wavelength of the real part of the dielectric function as short as 1.36 {mu}m, while the plasmonic damping does not exceed 50 meV. Structural, electrical, and optical data consistently demonstrate a profound change of the Ga incorporation mode beyond concentrations of 10{sup 21} cm{sup -3} attended by deterioration of the plasmonic features.

  15. Single quantum dot emission at telecom wavelengths from metamorphic InAs/InGaAs nanostructures grown on GaAs substrates

    SciTech Connect

    Seravalli, L.; Trevisi, G.; Frigeri, P.; Rivas, D.; Munoz-Matutano, G.; Suarez, I.; Alen, B.; Canet, J.; Martinez-Pastor, J. P.

    2011-04-25

    We report on the growth by molecular beam epitaxy and the study by atomic force microscopy and photoluminescence of low density metamorphic InAs/InGaAs quantum dots. subcritical InAs coverages allow to obtain 10{sup 8} cm{sup -2} dot density and metamorphic In{sub x}Ga{sub 1-x}As (x=0.15,0.30) confining layers result in emission wavelengths at 1.3 {mu}m. We discuss optimal growth parameters and demonstrate single quantum dot emission up to 1350 nm at low temperatures, by distinguishing the main exciton complexes in these nanostructures. Reported results indicate that metamorphic quantum dots could be valuable candidates as single photon sources for long wavelength telecom windows.

  16. Choice of the proper wavelength for photochemotherapy

    NASA Astrophysics Data System (ADS)

    Moan, Johan; Iani, Vladimir; Ma, LiWei

    1996-01-01

    All photosensitizers applied in experimental- and clinical-photochemotherapy (PCT) have broad absorption spectra stretching from the ultraviolet up to 6 - 700 nm. Light of wavelengths in the red part of the spectrum is chosen for PCT even though the extinction coefficients of the sensitizers are usually smaller in this wavelength region than at shorter wavelengths. Thus, if one wants to treat superficial tumors or skin disorders, this may be a wrong choice. Two pieces of information are needed in order to make a proper choice of wavelength to treat a lesion of a given depth: the wavelength dependence of the optical penetration depth into tissue, and the action spectrum for tumor destruction. Additionally, the skin photosensitivity induced by the drug should be considered. We have non-invasively measured the optical penetration spectra of human tissues in vivo and the fluorescence excitation spectra for several sensitizers, including protoporphyrin (PpIX), in cells. Assuming that the action spectrum for cell inactivation can be approximated by the fluorescence excitation spectrum of the sensitizer -- which is indeed the case for a number of sensitizers in cells in vitro -- we have considered the situation for 5-aminolevulinic acid-induced PpIX in human tissue. All the way down to about 2 mm below the surface light in the Soret band (-410 nm) would give the largest cell inactivation, while at depth exceeding 2 mm, the conventional 635 nm light would be optimal. Light at the argon laser wavelength 514.5 nm is more efficient than light at 635 nm down to 1 mm. From the surface and down to 6 mm, the 635 nm peak of the excitation spectrum of PpIX, as evaluated per photon incident on the skin surface, is redshifted by less than 2 nm. In some cases photosensitizing photoproducts are formed during PCT, such as photoprotoporphyrin during PCT with PpIX. In such cases it may be advantageous to apply a broad-band light source with a spectrum that covers also part of the action

  17. Photoacoustic optical properties at UV, VIS, and near IR wavelengths for laboratory generated and winter time ambient urban aerosols

    SciTech Connect

    Gyawali, Madhu S.; Arnott, W. Patrick; Zaveri, Rahul A.; Song, Chen; Moosmuller, H.; Liu, Li; Mishchenko, M.; Chen, L-W A.; Green, M.; Watson, J. G.; Chow, J. C.

    2012-03-08

    We present the laboratory and ambient photoacoustic (PA) measurement of aerosol light absorption coefficients at ultraviolet wavelength (i.e., 355 nm) and compare with measurements at 405, 532, 870, and 1047 nm. Simultaneous measurements of aerosol light scattering coefficients were achieved by the integrating reciprocal nephelometer within the PA's acoustic resonator. Absorption and scattering measurements were carried out for various laboratory generated aerosols, including salt, incense, and kerosene soot to evaluate the instrument calibration and gain insight on the spectral dependence of aerosol light absorption and scattering. Ambient measurements were obtained in Reno, Nevada, between 18 December 2009 and 18 January 2010. The measurement period included days with and without strong ground level temperature inversions, corresponding to highly polluted (freshly emitted aerosols) and relatively clean (aged aerosols) conditions. Particulate matter (PM) concentrations were measured and analyzed with other tracers of traffic emissions. The temperature inversion episodes caused very high concentration of PM{sub 2.5} and PM{sub 10} (particulate matter with aerodynamic diameters less than 2.5 {mu}m and 10 {mu}m, respectively) and gaseous pollutants: carbon monoxide (CO), nitric oxide (NO), and nitrogen dioxide (NO{sub 2}). The diurnal change of absorption and scattering coefficients during the polluted (inversion) days increased approximately by a factor of two for all wavelengths compared to the clean days. The spectral variation in aerosol absorption coefficients indicated a significant amount of absorbing aerosol from traffic emissions and residential wood burning. The analysis of single scattering albedo (SSA), Angstrom exponent of absorption (AEA), and Angstrom exponent of scattering (AES) for clean and polluted days provides evidences that the aerosol aging and coating process is suppressed by strong temperature inversion under cloudy conditions. In general

  18. Multi-Wavelength Observations of Supernova Remnants

    NASA Technical Reports Server (NTRS)

    Williams, B.

    2012-01-01

    Supernova remnants (SNRs) provide a laboratory for studying various astrophysical processes, including particle acceleration, thermal and non thermal emission processes across the spectrum, distribution of heavy elements, the physics of strong shock waves, and the progenitor systems and environments of supernovae. Long studied in radio and X-rays, the past decade has seen a dramatic increase in the detection and subsequent study of SNRs in the infrared and gamma-ray regimes. Understanding the evolution of SNRs and their interaction with the interstellar medium requires a multi-wavelength approach. I will review the various physical processes observed in SNRs and how these processes are intertwined. In particular, I will focus on X-ray and infrared observations, which probe two very different but intrinsically connected phases of the ISM: gas and dust. I will discuss results from multi-wavelength studies of several SNRs at various stages of evolution, including Kepler, RCW 86, and the Cygnus Loop.

  19. WAVELENGTH CALIBRATION OF THE HAMILTON ECHELLE SPECTROGRAPH

    SciTech Connect

    Pakhomov, Yu. V.; Zhao, G.

    2013-10-01

    We present the wavelength calibration of the Hamilton Echelle Spectrograph at Lick Observatory. The main problem with the calibration of this spectrograph arises from the fact that thorium lines are absent in the spectrum of the presumed ThAr hollow-cathode lamp now under operation; numerous unknown strong lines, which have been identified as titanium lines, are present in the spectrum. We estimate the temperature of the lamp's gas which permits us to calculate the intensities of the lines and to select a large number of relevant Ti I and Ti II lines. The resulting titanium line list for the Lick hollow-cathode lamp is presented. The wavelength calibration using this line list was made with an accuracy of about 0.006 Å.

  20. Dual-wavelength laser with topological charge

    NASA Astrophysics Data System (ADS)

    Yu, Haohai; Xu, Miaomiao; Zhao, Yongguang; Wang, Yicheng; Han, Shuo; Zhang, Huaijin; Wang, Zhengping; Wang, Jiyang

    2013-09-01

    We demonstrate the simultaneous oscillation of different photons with equal orbital angular momentum in solid-state lasers for the first time to our knowledge. Single tunable Hermite-Gaussian (HG0,n) (0 ≤ n ≤ 7) laser modes with dual wavelength were generated using an isotropic cavity. With a mode-converter, the corresponding Laguerre-Gaussian (LG0,n) laser modes were obtained. The oscillating laser modes have two types of photons at the wavelengths of 1077 and 1081 nm and equal orbital angular momentum of nħ per photon. These results identify the possibility of simultaneous oscillation of different photons with equal and controllable orbital angular momentum. It can be proposed that this laser should have promising applications in many fields based on its compact structure, tunable orbital angular momentum, and simultaneous oscillation of different photons with equal orbital angular momentum.

  1. The Long Wavelength Array Software Library

    NASA Astrophysics Data System (ADS)

    Dowell, Jayce; Wood, Daniel; Stovall, Kevin; Ray, Paul S.; Clarke, Tracy; Taylor, Gregory

    2012-12-01

    The Long Wavelength Array Software Library (LSL) is a Python module that provides a collection of utilities to analyze and export data collected at the first station of the Long Wavelength Array, LWA1. Due to the nature of the data format and large-N (≳100 inputs) challenges faced by the LWA, currently available software packages are not suited to process the data. Using tools provided by LSL, observers can read in the raw LWA1 data, synthesize a filter bank, and apply incoherent de-dispersion to the data. The extensible nature of LSL also makes it an ideal tool for building data analysis pipelines and applying the methods to other low frequency arrays.

  2. Aperture-synthesis interferometry at optical wavelengths

    NASA Technical Reports Server (NTRS)

    Burke, Bernard F.

    1987-01-01

    The prospects for applying aperture-synthesis interferometry to the optical domain are reviewed. The radio examples such as the VLA provide a model, since the concepts are equally valid for radio and optical wavelengths. If scientific problems at the milliarc-second resolution level (or better) are to be addressed, a space-based optical array seems to be the only practical alternative, for the same reasons that dictated array development at radio wavelengths. One concept is examined, and speculations are offered concerning the prospects for developing real systems. Phase-coherence is strongly desired for a practical array, although self-calibration and phase-closure techniques allow one to relax the restriction on absolute phase stability. The design of an array must be guided by the scientific problems to be addressed.

  3. Coordinated observations of PHEMU at radio wavelengths.

    NASA Astrophysics Data System (ADS)

    Pluchino, S.; Schillirò, F.; Salerno, E.; Pupillo, G.; Kraus, A.; Mack, K.-H.

    We present preliminary results for our study of mutual phenomena of the Galilean satellites performed at radio wavelengths with the Medicina and Noto antennas of the Istituto di Radioastronomia \\textendash{} INAF, and with the Effelsberg 100-m radio telescope of the Max-Planck-Institute for Radioastronomy. Measurements of the radio flux density variation occurred during the mutual occultations of Io by Europa and Ganymede were carried out during the PHEMU09 campaign at K- and Q-band. Flux density variations observed for the first time at radio wavelengths are consistent with the typical optical patterns measured when partial occultations occurred. The flux density drops indicate a non-linear dependence with the percentage of overlapped area.

  4. Short wavelength striations on expanding plasma clouds

    SciTech Connect

    Winske, D.; Gary, S.P.

    1989-01-01

    The growth and evolution of short wavelength (

  5. Deformable mirror for short wavelength applications

    DOEpatents

    Chapman, Henry N.; Sweeney, Donald W.

    1999-01-01

    A deformable mirror compatible with short wavelength (extreme ultraviolet) radiation that can be precisely controlled to nanometer and subnanometer accuracy is described. Actuators are coupled between a reaction plate and a face plate which has a reflective coating. A control system adjusts the voltage supplied to the actuators; by coordinating the voltages supplied to the actuators, the reflective surface of the mirror can be deformed to correct for dimensional errors in the mirror or to produce a desired contour.

  6. Tuning the Activation Wavelength of Photochromic Oxazines.

    PubMed

    Swaminathan, Subramani; Garcia-Amorós, Jaume; Thapaliya, Ek Raj; Nonell, Santi; Captain, Burjor; Raymo, Françisco M

    2016-06-17

    The activation wavelength of a photochromic oxazine can be shifted bathochromically with the introduction of a methoxy substituent on the chromophore responsible for initiating the photochemical transformation. This structural modification permits switching under mild illumination conditions, enhances the photoisomerization quantum yield and ensures outstanding fatigue resistance. Thus, these results can guide the design of new members of this family of photoresponsive molecular switches with improved photochemical and photophysical properties. PMID:27003328

  7. High-speed wavelength-swept lasers

    NASA Astrophysics Data System (ADS)

    Hsu, Kevin

    2006-05-01

    High-speed wavelength-swept lasers capable of providing wide frequency chirp and flexible temporal waveforms could enable numerous advanced functionalities for defense and security applications. Powered by high spectral intensity at rapid sweep rates across a wide wavelength range in each of the 1060nm, 1300nm, and 1550nm spectral windows, these swept-laser systems have demonstrated real-time monitoring and superior signal-to-noise ratio measurements in optical frequency domain imaging, fiber-optic sensor arrays, and near-IR spectroscopy. These same capabilities show promising potentials in laser radar and remote sensing applications. The core of the high-speed swept laser incorporates a semiconductor gain module and a high-performance fiber Fabry- Perot tunable filter (FFP-TF) to provide rapid wavelength scanning operations. This unique design embodies the collective advantages of the semiconductor amplifier's broad gain-bandwidth with direct modulation capability, and the FFP-TF's wide tuning ranges (>200nm), high finesse (1000 to 10,000), low-loss (<3dB), and fast scan rates reaching 20KHz. As a result, the laser can sweep beyond 100nm in 25μsec, output a scanning peak power near mW level, and exhibit excellent peak signal-to-spontaneous-emission ratio >80dB in static mode. When configured as a seed laser followed by post amplification, the swept spectrum and power can be optimized for Doppler ranging and remote sensing applications. Furthermore, when combined with a dispersive element, the wavelength sweep can be converted into high-speed and wide-angle spatial scanning without moving parts.

  8. Tuning the Activation Wavelength of Photochromic Oxazines.

    PubMed

    Swaminathan, Subramani; Garcia-Amorós, Jaume; Thapaliya, Ek Raj; Nonell, Santi; Captain, Burjor; Raymo, Françisco M

    2016-06-17

    The activation wavelength of a photochromic oxazine can be shifted bathochromically with the introduction of a methoxy substituent on the chromophore responsible for initiating the photochemical transformation. This structural modification permits switching under mild illumination conditions, enhances the photoisomerization quantum yield and ensures outstanding fatigue resistance. Thus, these results can guide the design of new members of this family of photoresponsive molecular switches with improved photochemical and photophysical properties.

  9. Source of coherent short wavelength radiation

    DOEpatents

    Villa, Francesco

    1990-01-01

    An apparatus for producing coherent radiation ranging from X-rays to the far ultraviolet (i.e., 1 Kev to 10 eV) utilizing the Compton scattering effect. A photon beam from a laser is scattered on a high energy electron bunch from a pulse power linac. The short wavelength radiation produced by such scattering has sufficient intensity and spatial coherence for use in high resolution applications such as microscopy.

  10. Effective wavelength scaling of rectangular aperture antennas.

    PubMed

    Chen, Yuanyuan; Yu, Li; Zhang, Jiasen; Gordon, Reuven

    2015-04-20

    We investigate the resonances of aperture antennas from the visible to the terahertz regime, with comparison to comprehensive simulations. Simple piecewise analytic behavior is found for the wavelength scaling over the entire spectrum, with a linear regime through the visible and near-IR. This theory will serve as a useful and simple design tool for applications including biosensors, nonlinear plasmonics and surface enhanced spectroscopies. PMID:25969079

  11. Varactor diodes for millimeter and submillimeter wavelengths

    NASA Technical Reports Server (NTRS)

    Rizzi, Brian J.; Hesler, Jeffrey L.; Dossal, Hasan; Crowe, Thomas W.

    1992-01-01

    Whisker-contacted GaAs Schottky barrier varactor diodes are the most common high-frequency multiplier element in use today. They are inherently simple devices that have very high frequency response and have been used to supply local oscillator power for Schottky heterodyne receivers to frequencies approaching 700 GHz. This paper discusses the development of improved varactor diode technology for space based applications at millimeter and submillimeter wavelengths.

  12. Two-wavelength lidar inversion algorithm.

    PubMed

    Kunz, G J

    1999-02-20

    Potter [Appl. Opt. 26, 1250 (1987)] has presented a method to determine profiles of the atmospheric aerosol extinction coefficients by use of a two-wavelength lidar with the assumptions of a constant value for the extinction-to-backscatter ratio for each wavelength and a constant value for the ratio between the two extinction coefficients at the two wavelengths. Triggered by this idea, Ackermann [Appl. Opt. 36, 5134 (1997)] expanded this method to consider lidar returns that are a composition of scattering by atmospheric aerosols and molecules, assuming that the molecular scattering is known. In both papers the method is based on the well-known solutions of Bernoulli's differential equation in an iterative scheme with an unknown boundary transmission condition. This boundary condition is less sensitive to noise than boundary extinction conditions. My main purpose is to critically consider the principle behind Potter's method, because it seems that there are several reasons why the number of solutions is not limited to one, as suggested by his original work.

  13. Wavelength switching in an optical klystron

    SciTech Connect

    Berryman, K.W.; Smith, T.I.

    1995-12-31

    A symmetric optical klystron consists of two identical undulator sections separated a dispersive section. For a device of a given length, an optical klystron is capable of producing much more bunching, and therefore more gain, than a traditional undulator. Another consequence of introducing dispersion between two undulator sections is that the overall spontaneous radiation pattern results from the interference between the two undulator sections, and as such resembles a standard undulator radiation pattern modulated by a sinusoidal interference term. The presence of several wavelength peaks in the spontaneous lineshape implies an equal number of peaks in the gain spectrum. If the strength of the dispersion section is adjusted to provide nearly equal gain on the two largest of these peaks, then they will compete, and the FEL may switch wavelengths based on noise, cavity length, or other perturbations. We provide the first observations of this behavior, using the FIREFLY system at the Stanford Picosecond FEL Center. In FIREFLY, relative wavelength switching by more than 3%--more than twice the laser linewidth-has been observed by varying dispersion section strength, while at intermediate points stable switching has also been observed as a function of cavity length.

  14. Multiple wavelength X-ray monochromators

    DOEpatents

    Steinmeyer, Peter A.

    1992-11-17

    An improved apparatus and method is provided for separating input x-ray radiation containing first and second x-ray wavelengths into spatially separate first and second output radiation which contain the first and second x-ray wavelengths, respectively. The apparatus includes a crystalline diffractor which includes a first set of parallel crystal planes, where each of the planes is spaced a predetermined first distance from one another. The crystalline diffractor also includes a second set of parallel crystal planes inclined at an angle with respect to the first set of crystal planes where each of the planes of the second set of parallel crystal planes is spaced a predetermined second distance from one another. In one embodiment, the crystalline diffractor is comprised of a single crystal. In a second embodiment, the crystalline diffractor is comprised of a stack of two crystals. In a third embodiment, the crystalline diffractor includes a single crystal that is bent for focussing the separate first and second output x-ray radiation wavelengths into separate focal points.

  15. Multiple wavelength X-ray monochromators

    DOEpatents

    Steinmeyer, P.A.

    1992-11-17

    An improved apparatus and method is provided for separating input x-ray radiation containing first and second x-ray wavelengths into spatially separate first and second output radiation which contain the first and second x-ray wavelengths, respectively. The apparatus includes a crystalline diffractor which includes a first set of parallel crystal planes, where each of the planes is spaced a predetermined first distance from one another. The crystalline diffractor also includes a second set of parallel crystal planes inclined at an angle with respect to the first set of crystal planes where each of the planes of the second set of parallel crystal planes is spaced a predetermined second distance from one another. In one embodiment, the crystalline diffractor is comprised of a single crystal. In a second embodiment, the crystalline diffractor is comprised of a stack of two crystals. In a third embodiment, the crystalline diffractor includes a single crystal that is bent for focusing the separate first and second output x-ray radiation wavelengths into separate focal points. 3 figs.

  16. Long Wavelength Ripples in the Nearshore

    NASA Astrophysics Data System (ADS)

    Alcinov, T.; Hay, A. E.

    2008-12-01

    Sediment bedforms are ubiquitous in the nearshore environment, and their characteristics and evolution have a direct effect on the hydrodynamics and the rate of sediment transport. The focus of this study is long wavelength ripples (LWR) observed at two locations in the nearshore at roughly 3m water depth under combined current and wave conditions in Duck, North Carolina. LWR are straight-crested bedforms with wavelengths in the range of 20-200cm, and steepness of about 0.1. They occur in the build up and decay of storms, in a broader range of values of the flow parameters compared to other ripple types. The main goal of the study is to test the maximum gross bedform-normal transport (mGBNT) hypothesis, which states that the orientation of ripples in directionally varying flows is such that the gross sediment transport normal to the ripple crest is maximized. Ripple wavelengths and orientation are measured from rotary fanbeam images and current and wave conditions are obtained from electromagnetic (EM) flowmeters and an offshore pressure gauge array. Preliminary tests in which transport direction is estimated from the combined flow velocity vectors indicate that the mGBNT is not a good predictor of LWR orientation. Results from tests of the mGBNT hypothesis using a sediment transport model will be presented.

  17. Peripheral detection and resolution with mid-/long-wavelength and short-wavelength sensitive cone systems.

    PubMed

    Zhu, Hai-Feng; Zele, Andrew J; Suheimat, Marwan; Lambert, Andrew J; Atchison, David A

    2016-08-01

    This study compared neural resolution and detection limits of the human mid-/long-wavelength and short-wavelength cone systems with anatomical estimates of photoreceptor and retinal ganglion cell spacings and sizes. Detection and resolution limits were measured from central fixation out to 35° eccentricity across the horizontal visual field using a modified Lotmar interferometer. The mid-/long-wavelength cone system was studied using a green (550 nm) test stimulus to which S-cones have low sensitivity. To bias resolution and detection to the short-wavelength cone system, a blue (450 nm) test stimulus was presented against a bright yellow background that desensitized the M- and L-cones. Participants were three trichromatic males with normal visual functions. With green stimuli, resolution showed a steep central-peripheral gradient that was similar between participants, whereas the detection gradient was shallower and patterns were different between participants. Detection and resolution with blue stimuli were poorer than for green stimuli. The detection of blue stimuli was superior to resolution across the horizontal visual field and the patterns were different between participants. The mid-/long-wavelength cone system's resolution is limited by midget ganglion cell spacing and its detection is limited by the size of the M- and L-cone photoreceptors, consistent with previous observations. We found that no such simple relationships occur for the short-wavelength cone system between resolution and the bistratified ganglion cell spacing, nor between detection and the S-cone photoreceptor sizes.

  18. Peripheral detection and resolution with mid-/long-wavelength and short-wavelength sensitive cone systems.

    PubMed

    Zhu, Hai-Feng; Zele, Andrew J; Suheimat, Marwan; Lambert, Andrew J; Atchison, David A

    2016-08-01

    This study compared neural resolution and detection limits of the human mid-/long-wavelength and short-wavelength cone systems with anatomical estimates of photoreceptor and retinal ganglion cell spacings and sizes. Detection and resolution limits were measured from central fixation out to 35° eccentricity across the horizontal visual field using a modified Lotmar interferometer. The mid-/long-wavelength cone system was studied using a green (550 nm) test stimulus to which S-cones have low sensitivity. To bias resolution and detection to the short-wavelength cone system, a blue (450 nm) test stimulus was presented against a bright yellow background that desensitized the M- and L-cones. Participants were three trichromatic males with normal visual functions. With green stimuli, resolution showed a steep central-peripheral gradient that was similar between participants, whereas the detection gradient was shallower and patterns were different between participants. Detection and resolution with blue stimuli were poorer than for green stimuli. The detection of blue stimuli was superior to resolution across the horizontal visual field and the patterns were different between participants. The mid-/long-wavelength cone system's resolution is limited by midget ganglion cell spacing and its detection is limited by the size of the M- and L-cone photoreceptors, consistent with previous observations. We found that no such simple relationships occur for the short-wavelength cone system between resolution and the bistratified ganglion cell spacing, nor between detection and the S-cone photoreceptor sizes. PMID:27580041

  19. A Model Secondary (6-12) Plan for Reading Intervention and Development: A Response to Requests from Minnesota Schools and Districts to Provide Guidance in Developing Reading Intervention Programs for Secondary Students

    ERIC Educational Resources Information Center

    Ferraro, Jan; Houck, Bonnie; Klund, Sue; Hexum-Platzer, Sharon; Vortman-Smith, Jan

    2006-01-01

    The "Model Secondary (6-12) Plan for Reading Intervention and Development" has been designed to meet the cognitive needs of middle school through high school students whose reading performance ranges from those significantly below expectation through those reading at or above grade level. The reading needs of the population of students in need of…

  20. Ion-implanted WN 0.25{mu}m gate MESFET fabricated using I-line photolithography for application to MMIC and digital IC

    SciTech Connect

    Oh, E.O.; Yang, J.W.; Park, C.S.

    1995-12-31

    Straightforward WN 0.25{mu}m gate MESFET process based on direct ion-implantation and i-line photolithography with double exposure process has produced high performance MESFETs. The maximum transconductance of 600mS/mm and the k-factor of 450ms/Vmm were obtained. As high as 65GHz of cut-off frequency has been realized without any deembedding of parasitic effects. The MESFET shows the minimum noise figure of 0.87 dB and the associated gain of 9.97dB at 12GHz.

  1. Growth and characteristics of ultralow threshold 1.45 {mu}m metamorphic InAs tunnel injection quantum dot lasers on GaAs

    SciTech Connect

    Mi, Z.; Bhattacharya, P.; Yang, J.

    2006-10-09

    The molecular beam epitaxial growth and characteristics of 1.45 {mu}m metamorphic InAs quantum dot tunnel injection lasers on GaAs have been studied. Under optimized growth conditions, the quantum dots exhibit photoluminescence linewidths {approx}30 meV and high intensity at room temperature. The lasers are characterized by ultralow threshold current (63 A/cm{sup 2}), large frequency response (f{sub -3dB}=8 GHz), and near-zero {alpha} parameter and chirp.

  2. Wavelength meter having single mode fiber optics multiplexed inputs

    DOEpatents

    Hackel, R.P.; Paris, R.D.; Feldman, M.

    1993-02-23

    A wavelength meter having a single mode fiber optics input is disclosed. The single mode fiber enables a plurality of laser beams to be multiplexed to form a multiplexed input to the wavelength meter. The wavelength meter can provide a determination of the wavelength of any one or all of the plurality of laser beams by suitable processing. Another aspect of the present invention is that one of the laser beams could be a known reference laser having a predetermined wavelength. Hence, the improved wavelength meter can provide an on-line calibration capability with the reference laser input as one of the plurality of laser beams.

  3. Wavelength meter having single mode fiber optics multiplexed inputs

    DOEpatents

    Hackel, Richard P.; Paris, Robert D.; Feldman, Mark

    1993-01-01

    A wavelength meter having a single mode fiber optics input is disclosed. The single mode fiber enables a plurality of laser beams to be multiplexed to form a multiplexed input to the wavelength meter. The wavelength meter can provide a determination of the wavelength of any one or all of the plurality of laser beams by suitable processing. Another aspect of the present invention is that one of the laser beams could be a known reference laser having a predetermined wavelength. Hence, the improved wavelength meter can provide an on-line calibration capability with the reference laser input as one of the plurality of laser beams.

  4. TASTRAK spectroscopy of polonium-210 alpha-particle activity at bone surfaces: Evidence for a concentrated surface deposit less than 3 {mu}m deep

    SciTech Connect

    Salmon, P.L.; Henshaw, D.L.; Keitch, P.A.; Allen, J.E.; Fews, A.P.

    1994-10-01

    The technique of {alpha}-particle spectroscopy by CR-39 type TASTRAK plastic has been used to study the depth distribution of natural {alpha}-particle emitters at the surface of human bone. The predominant component of this {alpha}-particle activity was {sup 210}Po supported by {sup 210}Pb, although a smaller activity of {sup 226}Ra was also detected. Autopsy samples of human femur and cranium were obtained from subjects age 63 to 86. Both cortical and trabecular surfaces were analyzed. The results indicate that {sup 210}Pb-supported {sup 210}Po is concentrated at the surfaces of human bone from elderly subjects, in a narrow band 3 {mu}m deep or less, by a factor of about four. As a result, the {alpha}-particle dose to the nuclei of cells lining bone surfaces is around 1.8 times greater than that calculated for a uniform volume distribution. Polonium-210 activity indicates the distribution of {sup 210}Pb, and of stable lead, received by continuous intake throughout life at a very low level. A persistent bone surface concentration of lead and other osteotropic metals may be associated with the hypermineralized layer about 1 {mu}m thick which occurs at the surface of resting bone mineral. 31 refs., 9 figs., 3 tabs.

  5. Diode-laser-pumped 1.065-{mu}m Nd:Sr{sub 5}(VO{sub 4}){sub 3}F laser and its intracavity frequency doubling

    SciTech Connect

    Zhao, S.; Wang, Q.; Zhang, X.; Wang, S.; Zhao, L.; Sun, L.; Zhang, S.

    1996-12-01

    Nd:Sr{sub 5}(VO{sub 4}){sub 3}F, known as Nd:S-VAP, is a new material for efficient and miniature diode-pumped solid state lasers. By using a laser-diode pump operating at 809 nm, Nd:S-VAP is successfully lased at 1.065 {mu}m. A slope efficiency of 43.5{percent} and a laser threshold of only 11 mW are measured. The theoretical formulas for threshold power and slope efficiency are written and the theoretical calculations are in agreement with the experimental results. In addition, by using KTP as an intracavity-doubling crystal, the intracavity frequency of the Nd:S-VAP laser at 0.5325 {mu}m is also realized. The threshold power is 13.2 mW and the TEM{sub 00} mode green laser output power is 25.6 mW at 200 mW incident pump power, corresponding to an optical efficiency of 12.8{percent}. In addition a way to improve efficiency is discussed. {copyright} {ital 1996 Society of Photo{minus}Optical Instrumentation Engineers.}

  6. InN/InGaN multiple quantum wells emitting at 1.5 {mu}m grown by molecular beam epitaxy

    SciTech Connect

    Grandal, J.; Pereiro, J.; Bengoechea-Encabo, A.; Fernandez-Garrido, S.; Sanchez-Garcia, M. A.; Munoz, E.; Calleja, E.

    2011-02-07

    This work reports on the growth by molecular beam epitaxy and characterization of InN/InGaN multiple quantum wells (MQWs) emitting at 1.5 {mu}m. X-ray diffraction (XRD) spectra show satellite peaks up to the second order. Estimated values of well (3 nm) and barrier (9 nm) thicknesses were derived from transmission electron microscopy and the fit between experimental data and simulated XRD spectra. Transmission electron microscopy and XRD simulations also confirmed that the InGaN barriers are relaxed with respect to the GaN template, while the InN MQWs grew under biaxial compression on the InGaN barriers. Low temperature (14 K) photoluminescence measurements reveal an emission from the InN MQWs at 1.5 {mu}m. Measurements as a function of temperature indicate the existence of localized states, probably due to InN quantum wells' thickness fluctuations as observed by transmission electron microscopy.

  7. Bulk acousto-optic wavelength agile filter module for a wavelength-multiplexed optical scanner.

    PubMed

    Yaqoob, Zahid; Riza, Nabeel A

    2005-05-01

    An acousto-optic tunable filter-based wavelength-selection module with features optimized for a wavelength-multiplexed optical scanner (W-MOS) is proposed and demonstrated. The W-MOS produces high-speed multiple scan beams if it is engaged with an agile tunable source with multiwavelength generation capability. In particular, the proposed fiber-connected module features high-speed, low-loss, narrow-linewidth, and single-multiple wavelength selection by means of radio frequency drive signal control for single- or multiple-beam scan operations. The unique module offers input laser beam power control that in turn delivers the desired scanned laser beam power shaping. Experimental results match module design theory and demonstrate a fast 5.4-micros wavelength selection speed, a low (1.53-dB) fiber-to-fiber optical insertion loss, a 5.55-nm 3-dB spectral width, and a 1500-1600-nm agile wavelength operational band.

  8. Superheterodyne configuration for two-wavelength interferometry applied to absolute distance measurement

    SciTech Connect

    Le Floch, Sebastien; Salvade, Yves; Droz, Nathalie; Mitouassiwou, Rostand; Favre, Patrick

    2010-02-01

    We present a new superheterodyne technique for long-distance measurements by two-wavelength interferometry (TWI). While conventional systems use two acousto-optic modulators to generate two different heterodyne frequencies, here the two frequencies result from synchronized sweeps of optical and radio frequencies. A distributed feedback laser source is injected in an intensity modulator that is driven at the half-wave voltage mode. A radio-frequency signal is applied to this intensity modulator to generate two optical sidebands around the optical carrier. This applied radio frequency consists of a digital ramp between 13 and 15 GHz, with 1 ms duration and with an accuracy of better than 1 ppm. Simultaneously, the laser source is frequency modulated by a current modulation that is synchronized on the radio-frequency ramp as well as on a triangle waveform. These two frequency-swept optical signals at the output of the modulator illuminate a Michelson interferometer and create two distinct distance-dependent heterodyne frequencies on the photodetector. The superheterodyne signal is then detected and bandpass filtered to retrieve the absolute distance measurement. Experiments between 1 and 15 m confirm the validity of this new concept, leading to a distance accuracy of {+-} 50 {mu}m for a 1 ms acquisition time.

  9. Technique for rapid at-wavelength inspection of extreme ultraviolet mask blanks

    SciTech Connect

    Spector, S. J.; White, D. L.; Tennant, D. M.; Ocola, L. E.; Novembre, A. E.; Peabody, M. L.; Wood, O. R. II

    1999-11-01

    We have developed two new methods for at-wavelength inspection of mask blanks for extreme-ultraviolet (EUV) lithography. In one method an EUV photoresist is applied directly to a mask blank which is then flood exposed with EUV light and partially developed. In the second method, the photoresist is applied to an EUV transparent membrane that is placed in close proximity to the mask and then exposed and developed. Both reflectivity defects and phase defects alter the exposure of the resist, resulting in mounds of resist at defect sites that can then be located by visual inspection. In the direct application method, a higher contrast resist was shown to increase the height of the mounds, thereby improving the sensitivity of the technique. In the membrane method, a holographic technique was used to reconstruct an image of the mask, revealing the presence of very small defects, approximately 0.2 {mu}m in size. The demonstrated clean transfer of phase and amplitude defects to resist features on a membrane will be important when flagging defects in an automatic inspection tool. (c) 1999 American Vacuum Society.

  10. Dual-wavelength moisture meter for clay

    NASA Astrophysics Data System (ADS)

    Norgia, Michele; Pesatori, Alessandro

    2012-10-01

    An optical sensor for measuring the moisture level of clay has been realized by a couple of telecommunications lasers at 1300 and 1550 nm. The sensor can operate directly during building material production. The measurement principle is based on the measurement of the optical reflection at different wavelengths in the infrared region. Custom low-noise electronics allows rejecting disturbances of ambient light, and a digital processing makes the system independent on the clay distance. By means of a proper calibration, the sensor can monitor the moisture level during brick production, without moving parts or optical filters.

  11. High performance optical wavelength multiplexer-demultiplexer.

    PubMed

    Dobrowolski, J A; Hara, E H; Sullivan, B T; Waldorf, A J

    1992-07-01

    The principle of an optical wavelength multiplexer-demultiplexer is described in which the signals undergo repeated reflections from special filter elements that can be designed for a wide range of cross-talk ratios. The insertion losses of these units can be quite small and they can be implemented to provide simultaneous multichannel two-way transmission. In a preliminary investigation of an experimental prototype an insertion loss of 0.5 dB and a cross talk of -35 dB were demonstrated. The multiplexer-demultiplexer is expected to have a long life and high reliability.

  12. Wavelength de-multiplexing metasurface hologram

    PubMed Central

    Wang, Bo; Quan, Baogang; He, Jingwen; Xie, Zhenwei; Wang, Xinke; Li, Junjie; Kan, Qiang; Zhang, Yan

    2016-01-01

    A wavelength de-multiplexing metasurface hologram composed of subwavelength metallic antennas is designed and demonstrated experimentally in the terahertz (THz) regime. Different character patterns are generated at the separated working frequencies 0.50 THz and 0.63 THz which determine a narrow frequency bandwidth of 130 GHz. The two working frequencies are around the central resonance frequency of the antennas where antennas behave strong wavefront modulation. Each antenna is fully utilized to control the wavefront of the metasurface at different frequencies by an optimization algorithm. The results demonstrate a candidate way to design multi-colors optical display elements. PMID:27752118

  13. Quasi-optical diplexer for millimeter wavelengths.

    PubMed

    Payne, J M; Wordeman, M R

    1978-12-01

    A quasi-optical diplexer for injection of signal and local oscillator frequencies into a mixer at millimeter wave-lengths is described. The diplexer accepts both image and signal bands, presents low loss at both the signal and local oscillator frequencies and rejects local oscillator noise at the signal frequency. The configuration of the device makes it particularly useful for Cassegrain receivers using a cooled mixer and a lens corrected feed system. The diplexer has been tested at 150 GHz on the 11-m radio telescope operated by The National Radio Astronomy Observatory in Tucson, Arizona.

  14. Multi-wavelength compressive computational ghost imaging

    NASA Astrophysics Data System (ADS)

    Welsh, Stephen S.; Edgar, Matthew P.; Jonathan, Phillip; Sun, Baoqing; Padgett, Miles J.

    2013-03-01

    The field of ghost imaging encompasses systems which can retrieve the spatial information of an object through correlated measurements of a projected light field, having spatial resolution, and the associated reflected or transmitted light intensity measured by a photodetector. By employing a digital light projector in a computational ghost imaging system with multiple spectrally filtered photodetectors we obtain high-quality multi-wavelength reconstructions of real macroscopic objects. We compare different reconstruction algorithms and reveal the use of compressive sensing techniques for achieving sub-Nyquist performance. Furthermore, we demonstrate the use of this technology in non-visible and fluorescence imaging applications.

  15. Quantum cascade lasers designed toward shorter wavelengths

    NASA Astrophysics Data System (ADS)

    Xu, Jilian; Liu, Lei; Li, Bing Hui; Zhang, Zhenzhong; Ma, Jian; Liu, Kewei; He, Jun; Shen, D. Z.

    2016-02-01

    Quantum cascade lasers (QCLs) are normally based on one-dimensional confined quantum wells. In this scheme, it is still a challenge to produce lasing with a frequency higher than mid-infrared. Here, we discuss the possibility to extend the spectral range of QCLs to the higher frequency region by adding another dimensional confinement. Taking the ZnO/MgO system as an example, we demonstrate theoretically that such a two-dimensional confined QCL can operate at wavelengths from the near-infrared λ =2.95 μm, 1.57 μm, 1.13 μm to the visible 734 nm.

  16. Quantum cascade lasers designed toward shorter wavelengths.

    PubMed

    Xu, Jilian; Liu, Lei; Li, Bing Hui; Zhang, Zhenzhong; Ma, Jian; Liu, Kewei; He, Jun; Shen, D Z

    2016-02-17

    Quantum cascade lasers (QCLs) are normally based on one-dimensional confined quantum wells. In this scheme, it is still a challenge to produce lasing with a frequency higher than mid-infrared. Here, we discuss the possibility to extend the spectral range of QCLs to the higher frequency region by adding another dimensional confinement. Taking the ZnO/MgO system as an example, we demonstrate theoretically that such a two-dimensional confined QCL can operate at wavelengths from the near-infrared [Formula: see text] μm, 1.57 μm, 1.13 μm to the visible 734 nm.

  17. Two wavelength division multiplexing WAN trials

    SciTech Connect

    Lennon, W.J.; Thombley, R.L.

    1995-01-20

    Lawrence Livermore National Laboratory, as a super-user, supercomputer, and super-application site, is anticipating the future bandwidth and protocol requirements necessary to connect to other such sites as well as to connect to remote-sited control centers and experiments. In this paper the authors discuss their vision of the future of Wide Area Networking, describe the plans for a wavelength division multiplexed link connecting Livermore with the University of California at Berkeley and describe plans for a transparent, {approx} 10 Gb/s ring around San Francisco Bay.

  18. Influence of spectral properties of wavelength-locked and wavelength-unlocked diode laser on fiber laser performances

    NASA Astrophysics Data System (ADS)

    Huang, Zhihua; Tang, Xuan; Zhao, Pengfei; Li, Zebiao; Li, Chengyu; Li, Qi; Guo, Chao; Lin, Honghuan; Wang, Jianjun; Jing, Feng

    2016-07-01

    The influence of the spectral properties of laser diode (LD) pump source, i.e. central wavelength and linewidth, on the fiber laser performances are studied. The absorption degradation ratio (ADR) is introduced and evaluated as a guide for pump selection and fiber laser design. The spectra of wavelength-locked and wavelength-unlocked LDs are measured and they are used for fiber laser amplification. The results show that the efficiency of the wavelength-locked LDs is higher than that of the wavelength-unlocked LDs at full current but the residual pump power of wavelength-locked LDs can be much higher at lower current because of the side band.

  19. Wavelength dependence of aerosol backscatter coefficients obtained by multiple wavelength Lidar measurements

    NASA Technical Reports Server (NTRS)

    Sasano, Y.; Browell, E. V.

    1986-01-01

    Aerosols are often classified into several general types according to their origins and composition, such as maritime, continental, and stratospheric aerosols, and these aerosol types generally have different characteristics in chemical and physical properties. The present study aims at demonstrating the potential for distinguishing these aerosol types by the wavelength dependence of their backscatter coefficients obtained from quantitative analyses of multiple wavelength lidar signals. Data from the NASA Airborne Differential Abosrption lidar (DIAL) S ystems, which can measure aerosol backscatter profiles at wavelenghts of 300, 600, and 1064 nm and ozone profiles of backscatter coefficients for these three wavelength were derived from the observations of aerosols of different types. Observations were performed over the Atlantic Ocean, the Southwestern United States, and French Guyana.

  20. Laser-to-electricity energy converter for short wavelengths

    NASA Technical Reports Server (NTRS)

    Stirn, R. J.; Yeh, Y. C. M.

    1975-01-01

    Short-wavelength energy converter can be made using Schottky barrier structure. It has wider band gap than p-n junction silicon semiconductors, and thus it has improved response at wavelengths down to and including ultraviolet region.

  1. Long-wavelength microinstabilities in toroidal plasmas

    SciTech Connect

    Tang, W.W.; Rewoldt, G.

    1993-01-01

    Realistic kinetic toroidal eigenmode calculations have been carried out to support a proper assessment of the influence of long-wavelength microturbulence on transport in tokamak plasmas. In order to efficiently evaluate large-scale kinetic behavior extending over many rational surfaces, significant improvements have been made to a toroidal finite element code used to analyze the fully two-dimensional (r,{theta}) mode structures of trapped-ion and toroidal ion temperature gradient (ITG) instabilities. It is found that even at very long wavelengths, these eigenmodes exhibit a strong ballooning character with the associated radial structure relatively insensitive to ion Landau damping at the rational surfaces. In contrast to the long-accepted picture that the radial extent of trapped-ion instabilities is characterized by the ion-gyroradius-scale associated with strong localization between adjacent rational surfaces, present results demonstrate that under realistic conditions, the actual scale is governed by the large-scale variations in the equilibrium gradients. Applications to recent measurements of fluctuation properties in TFTR L-mode plasmas indicate that the theoretical trends appear consistent with spectral characteristics as well as rough heuristic estimates of the transport level. Benchmarking calculations in support of the development of a three-dimensional toroidal gyrokinetic code indicate reasonable agreement with respect to both the properties of the eigenfunctions and the magnitude of the eigenvalues during the linear phase of the simulations of toroidal ITG instabilities.

  2. Long-wavelength microinstabilities in toroidal plasmas

    SciTech Connect

    Tang, W.W.; Rewoldt, G.

    1993-01-01

    Realistic kinetic toroidal eigenmode calculations have been carried out to support a proper assessment of the influence of long-wavelength microturbulence on transport in tokamak plasmas. In order to efficiently evaluate large-scale kinetic behavior extending over many rational surfaces, significant improvements have been made to a toroidal finite element code used to analyze the fully two-dimensional (r,[theta]) mode structures of trapped-ion and toroidal ion temperature gradient (ITG) instabilities. It is found that even at very long wavelengths, these eigenmodes exhibit a strong ballooning character with the associated radial structure relatively insensitive to ion Landau damping at the rational surfaces. In contrast to the long-accepted picture that the radial extent of trapped-ion instabilities is characterized by the ion-gyroradius-scale associated with strong localization between adjacent rational surfaces, present results demonstrate that under realistic conditions, the actual scale is governed by the large-scale variations in the equilibrium gradients. Applications to recent measurements of fluctuation properties in TFTR L-mode plasmas indicate that the theoretical trends appear consistent with spectral characteristics as well as rough heuristic estimates of the transport level. Benchmarking calculations in support of the development of a three-dimensional toroidal gyrokinetic code indicate reasonable agreement with respect to both the properties of the eigenfunctions and the magnitude of the eigenvalues during the linear phase of the simulations of toroidal ITG instabilities.

  3. Coherence techniques at extreme ultraviolet wavelengths

    SciTech Connect

    Chang, Chang

    2002-10-01

    The renaissance of Extreme Ultraviolet (EUV) and soft x-ray (SXR) optics in recent years is mainly driven by the desire of printing and observing ever smaller features, as in lithography and microscopy. This attribute is complemented by the unique opportunity for element specific identification presented by the large number of atomic resonances, essentially for all materials in this range of photon energies. Together, these have driven the need for new short-wavelength radiation sources (e.g. third generation synchrotron radiation facilities), and novel optical components, that in turn permit new research in areas that have not yet been fully explored. This dissertation is directed towards advancing this new field by contributing to the characterization of spatial coherence properties of undulator radiation and, for the first time, introducing Fourier optical elements to this short-wavelength spectral region. The first experiment in this dissertation uses the Thompson-Wolf two-pinhole method to characterize the spatial coherence properties of the undulator radiation at Beamline 12 of the Advanced Light Source. High spatial coherence EUV radiation is demonstrated with appropriate spatial filtering. The effects of small vertical source size and beamline apertures are observed. The difference in the measured horizontal and vertical coherence profile evokes further theoretical studies on coherence propagation of an EUV undulator beamline. A numerical simulation based on the Huygens-Fresnel principle is performed.

  4. SHORT-WAVELENGTH MAGNETIC BUOYANCY INSTABILITY

    SciTech Connect

    Mizerski, K. A.; Davies, C. R.; Hughes, D. W. E-mail: tina@maths.leeds.ac.uk

    2013-04-01

    Magnetic buoyancy instability plays an important role in the evolution of astrophysical magnetic fields. Here we revisit the problem introduced by Gilman of the short-wavelength linear stability of a plane layer of compressible isothermal fluid permeated by a horizontal magnetic field of strength decreasing with height. Dissipation of momentum and magnetic field is neglected. By the use of a Rayleigh-Schroedinger perturbation analysis, we explain in detail the limit in which the transverse horizontal wavenumber of the perturbation, denoted by k, is large (i.e., short horizontal wavelength) and show that the fastest growing perturbations become localized in the vertical direction as k is increased. The growth rates are determined by a function of the vertical coordinate z since, in the large k limit, the eigenmodes are strongly localized in the vertical direction. We consider in detail the case of two-dimensional perturbations varying in the directions perpendicular to the magnetic field, which, for sufficiently strong field gradients, are the most unstable. The results of our analysis are backed up by comparison with a series of initial value problems. Finally, we extend the analysis to three-dimensional perturbations.

  5. Wavelength-band-tuning photodiodes by using various metallic nanoparticles.

    PubMed

    Hwang, J D; Chan, Y D; Chou, T C

    2015-11-20

    Wavelength-band tuning was easily achieved in this work by depositing various metallic nanoparticles (NPs) on silicon p-n junction photodiodes (PDs). The normalization spectrum of the PDs deposited with gold (Au) NPs reveals a high-wavelength pass characteristic; the PDs with silver (Ag) NPs coating behave as a low-wavelength pass, and the PDs with Au/Ag bimetallic NPs appear as a band-wavelength pass PD with a full width at half maximum of 450 ∼ 630 nm. The issue of wavelength-band tuning is due to the different plasmonic resonance wavelengths associated with various metallic NPs. The extinction plot shows the Au NPs have a longer resonant wavelength of about 545 nm, leading to the incident light with a wavelength near or longer than 545 nm scattered by the Au NPs, hence a high-wavelength pass PD. The PDs with Ag NPs, due to the Ag NPs, exhibit a short resonant wavelength of 430 nm, and the short-wavelength incident light is absorbed near the silicon (Si) surface, where the Ag NPs is atop it. The shorter-wavelength incident light is enhanced by the plasmonic resonance of Ag NPs, making a low-wavelength PD. The Au/Ag NPs presents a resonant wavelength of 500 nm between the Au and Ag NPs. For the incident light with a wavelength close to 500 nm, a constructive interference causes a substantial increase in the local electromagnetic field, hence leading to a band-wavelength pass PD. PMID:26508114

  6. Wavelength-band-tuning photodiodes by using various metallic nanoparticles.

    PubMed

    Hwang, J D; Chan, Y D; Chou, T C

    2015-11-20

    Wavelength-band tuning was easily achieved in this work by depositing various metallic nanoparticles (NPs) on silicon p-n junction photodiodes (PDs). The normalization spectrum of the PDs deposited with gold (Au) NPs reveals a high-wavelength pass characteristic; the PDs with silver (Ag) NPs coating behave as a low-wavelength pass, and the PDs with Au/Ag bimetallic NPs appear as a band-wavelength pass PD with a full width at half maximum of 450 ∼ 630 nm. The issue of wavelength-band tuning is due to the different plasmonic resonance wavelengths associated with various metallic NPs. The extinction plot shows the Au NPs have a longer resonant wavelength of about 545 nm, leading to the incident light with a wavelength near or longer than 545 nm scattered by the Au NPs, hence a high-wavelength pass PD. The PDs with Ag NPs, due to the Ag NPs, exhibit a short resonant wavelength of 430 nm, and the short-wavelength incident light is absorbed near the silicon (Si) surface, where the Ag NPs is atop it. The shorter-wavelength incident light is enhanced by the plasmonic resonance of Ag NPs, making a low-wavelength PD. The Au/Ag NPs presents a resonant wavelength of 500 nm between the Au and Ag NPs. For the incident light with a wavelength close to 500 nm, a constructive interference causes a substantial increase in the local electromagnetic field, hence leading to a band-wavelength pass PD.

  7. Wavelength-band-tuning photodiodes by using various metallic nanoparticles

    NASA Astrophysics Data System (ADS)

    Hwang, J. D.; Chan, Y. D.; Chou, T. C.

    2015-11-01

    Wavelength-band tuning was easily achieved in this work by depositing various metallic nanoparticles (NPs) on silicon p-n junction photodiodes (PDs). The normalization spectrum of the PDs deposited with gold (Au) NPs reveals a high-wavelength pass characteristic; the PDs with silver (Ag) NPs coating behave as a low-wavelength pass, and the PDs with Au/Ag bimetallic NPs appear as a band-wavelength pass PD with a full width at half maximum of 450 ∼ 630 nm. The issue of wavelength-band tuning is due to the different plasmonic resonance wavelengths associated with various metallic NPs. The extinction plot shows the Au NPs have a longer resonant wavelength of about 545 nm, leading to the incident light with a wavelength near or longer than 545 nm scattered by the Au NPs, hence a high-wavelength pass PD. The PDs with Ag NPs, due to the Ag NPs, exhibit a short resonant wavelength of 430 nm, and the short-wavelength incident light is absorbed near the silicon (Si) surface, where the Ag NPs is atop it. The shorter-wavelength incident light is enhanced by the plasmonic resonance of Ag NPs, making a low-wavelength PD. The Au/Ag NPs presents a resonant wavelength of 500 nm between the Au and Ag NPs. For the incident light with a wavelength close to 500 nm, a constructive interference causes a substantial increase in the local electromagnetic field, hence leading to a band-wavelength pass PD.

  8. Wavelength Calibration Accuracy for the STIS CCD and MAMA Modes

    NASA Astrophysics Data System (ADS)

    Pascucci, Ilaria; Hodge, Phil; Proffitt, Charles R.; Ayres, T.

    2011-03-01

    Two calibration programs were carried out to determine the accuracy of the wavelength solutions for the most used STIS CCD and MAMA modes after Servicing Mission 4. We report here on the analysis of this dataset and show that the STIS wavelength solution has not changed after SM4. We also show that a typical accuracy for the absolute wavelength zero-points is 0.1 pixels while the relative wavelength accuracy is 0.2 pixels.

  9. Additive-Subtractive Two-Wavelength ESPI Contouring by Using a Synthetic Wavelength Phase Shift.

    PubMed

    Hack, E; Frei, B; Kästle, R; Sennhauser, U

    1998-05-01

    The addition correlation of two speckle fields by simultaneousillumination at different wavelengths is used for object contouring ina Twyman-Green-type interferometer. Fringe visibility is enhancedwhen the stochastic speckle background intensity obtained from areference plane modulation is subtracted. We calculate the contourphase map by using a phase-shift algorithm in the syntheticwavelength. A comparison with a sequential illumination, phasedifference method based on a laser wavelength phase shift isgiven. The test setup does not need to be stable on aninterferometric scale, and therefore a method is provided that lendsitself to applications in noisy environments.

  10. Wavelength-Division Multiplexing Of Bipolar Digital Signals

    NASA Technical Reports Server (NTRS)

    Gibbons, Ronnie D.; Ubele, John L., II

    1994-01-01

    In system, bipolar digital data transmitted by use of wavelength-division multiplexing on single optical fiber. Two different wavelengths used to transmit pulses signifying "positive" or "negative" bipolar digital data. Simultaneous absence of pulses at both wavelengths signifies digital "zero."

  11. Two-wavelength operation of the nonlinear fiber loop mirror.

    PubMed

    Blow, K J; Doran, N J; Nayar, B K; Nelson, B P

    1990-02-15

    We describe the two-wavelength operation of the nonlinear fiber loop mirror. In this mode of operation a high-power signal at one wavelength switches a low-power signal at another wavelength. This device is investigated both theoretically and experimentally. The experimental results show that the nonlinear loop mirror performs as an optical modulator that consists of all-fiber components.

  12. BLAST: CORRELATIONS IN THE COSMIC FAR-INFRARED BACKGROUND AT 250, 350, AND 500 mum REVEAL CLUSTERING OF STAR-FORMING GALAXIES

    SciTech Connect

    Viero, Marco P.; Martin, Peter G.; Netterfield, Calvin B.; Ade, Peter A. R.; Griffin, Matthew; Hargrave, Peter C.; Mauskopf, Philip; Moncelsi, Lorenzo; Pascale, Enzo; Bock, James J.; Chapin, Edward L.; Halpern, Mark; Marsden, Gaelen; Devlin, Mark J.; Klein, Jeff; Gundersen, Joshua O.; Hughes, David H.; MacTavish, Carrie J.; Negrello, Mattia; Olmi, Luca

    2009-12-20

    We detect correlations in the cosmic far-infrared background due to the clustering of star-forming galaxies in observations made with the Balloon-borne Large Aperture Submillimeter Telescope, at 250, 350, and 500 mum. We perform jackknife and other tests to confirm the reality of the signal. The measured correlations are well fitted by a power law over scales of 5'-25', with DELTAI/I = 15.1% +- 1.7%. We adopt a specific model for submillimeter sources in which the contribution to clustering comes from sources in the redshift ranges 1.3 <= z <= 2.2, 1.5 <= z <= 2.7, and 1.7 <= z <= 3.2, at 250, 350, and 500 mum, respectively. With these distributions, our measurement of the power spectrum, P(k{sub t}heta), corresponds to linear bias parameters, b = 3.8 +- 0.6, 3.9 +- 0.6, and 4.4 +- 0.7, respectively. We further interpret the results in terms of the halo model, and find that at the smaller scales, the simplest halo model fails to fit our results. One way to improve the fit is to increase the radius at which dark matter halos are artificially truncated in the model, which is equivalent to having some star-forming galaxies at z >= 1 located in the outskirts of groups and clusters. In the context of this model, we find a minimum halo mass required to host a galaxy is log(M{sub min}/M{sub sun}) = 11.5{sup +0.4}{sub -0.1}, and we derive effective biases b{sub eff} = 2.2 +- 0.2, 2.4 +- 0.2, and 2.6 +- 0.2, and effective masses log(M{sub eff}/M{sub odot})=12.9+-0.3, 12.8 +- 0.2, and 12.7 +- 0.2, at 250, 350 and 500 mum, corresponding to spatial correlation lengths of r{sub 0} = 4.9, 5.0, and 5.2+-0.7 h{sup -1}Mpc, respectively. Finally, we discuss implications for clustering measurement strategies with Herschel and Planck.

  13. Multi-Wavelength Views of Messier 81

    NASA Technical Reports Server (NTRS)

    2003-01-01

    [figure removed for brevity, see original site] Click on individual images below for larger view

    [figure removed for brevity, see original site]

    [figure removed for brevity, see original site]

    [figure removed for brevity, see original site]

    [figure removed for brevity, see original site]

    The magnificent spiral arms of the nearby galaxy Messier 81 are highlighted in this image from NASA's Spitzer Space Telescope. Located in the northern constellation of Ursa Major (which also includes the Big Dipper), this galaxy is easily visible through binoculars or a small telescope. M81 is located at a distance of 12 million light-years.

    The main image is a composite mosaic obtained with the multiband imaging photometer for Spitzer and the infrared array camera. Thermal infrared emission at 24 microns detected by the photometer (red, bottom left inset) is combined with camera data at 8.0 microns (green, bottom center inset) and 3.6 microns (blue, bottom right inset).

    A visible-light image of Messier 81, obtained at Kitt Peak National Observatory, a ground-based telescope, is shown in the upper right inset. Both the visible-light picture and the 3.6-micron near-infrared image trace the distribution of stars, although the Spitzer image is virtually unaffected by obscuring dust. Both images reveal a very smooth stellar mass distribution, with the spiral arms relatively subdued.

    As one moves to longer wavelengths, the spiral arms become the dominant feature of the galaxy. The 8-micron emission is dominated by infrared light radiated by hot dust that has been heated by nearby luminous stars. Dust in the galaxy is bathed by ultraviolet and visible light from nearby stars. Upon absorbing an ultraviolet or visible-light photon, a dust grain is heated and re-emits the energy at longer infrared wavelengths. The dust particles are composed of silicates (chemically similar to beach sand), carbonaceous grains and polycyclic aromatic hydrocarbons and

  14. THE INFRARED SPECTRA OF POLYCYCLIC AROMATIC HYDROCARBONS WITH EXCESS PERIPHERAL H ATOMS (H {sub n} -PAHs) AND THEIR RELATION TO THE 3.4 AND 6.9 {mu}m PAH EMISSION FEATURES

    SciTech Connect

    Sandford, Scott A.; Bernstein, Max P.; Materese, Christopher K.

    2013-03-01

    Polycyclic aromatic hydrocarbons (PAHs) are likely responsible for the family of infrared emission features seen in a wide variety of astrophysical environments. A potentially important subclass of these materials are PAHs whose edges contain excess H atoms (H {sub n} -PAHs). This type of compound may be present in space, but it has been difficult to assess this possibility because of a lack of suitable laboratory spectra to assist with analysis of astronomical data. We present 4000-500 cm{sup -1} (2.5-20 {mu}m) infrared spectra of 23 H {sub n} -PAHs and related molecules isolated in argon matrices under conditions suitable for interpretation of astronomical data. Spectra of molecules with mixed aromatic and aliphatic domains show characteristics that distinguish them from fully aromatic PAH equivalents. Two major changes occur as PAHs become more hydrogenated: (1) aromatic C-H stretching bands near 3.3 {mu}m weaken and are replaced with stronger aliphatic bands near 3.4 {mu}m, and (2) aromatic C-H out-of-plane bending mode bands in the 11-15 {mu}m region shift and weaken concurrent with growth of a strong aliphatic -CH{sub 2}- deformation mode near 6.9 {mu}m. Implications for interpreting astronomical spectra are discussed with emphasis on the 3.4 and 6.9 {mu}m features. Laboratory data is compared with emission spectra from IRAS 21282+5050, an object with normal PAH emission features, and IRAS 22272+5435 and IRAS 0496+3429, two protoplanetary nebulae with abnormally large 3.4 {mu}m features. We show that 'normal' PAH emission objects contain relatively few H {sub n} -PAHs in their emitter populations, but less evolved protoplanetary nebulae may contain significant abundances of these molecules.

  15. DETECTION OF PARENT H{sub 2}O AND CO{sub 2} MOLECULES IN THE 2.5-5 {mu}m SPECTRUM OF COMET C/2007 N3 (LULIN) OBSERVED WITH AKARI

    SciTech Connect

    Ootsubo, Takafumi; Usui, Fumihiko; Hasegawa, Sunao; Ueno, Munetaka; Wada, Takehiko; Matsuhara, Hideo; Nakagawa, Takao; Murakami, Hiroshi; Kawakita, Hideyo; Ishiguro, Masateru; Furusho, Reiko; Watanabe, Jun-ichi; Sekiguchi, Tomohiko; Ohyama, Youichi; Oyabu, Shinki; Onaka, Takashi

    2010-07-01

    Comet C/2007 N3 (Lulin) was observed with the Japanese infrared satellite AKARI in the near-infrared at a post-perihelion heliocentric distance of 1.7 AU. Observations were performed with the spectroscopic (2.5-5.0 {mu}m) and imaging (2.4, 3.2, and 4.1 {mu}m) modes on 2009 March 30 and 31 UT, respectively. AKARI images of the comet exhibit a sunward crescent-like shape coma and a dust tail extended toward the anti-solar direction. The 4.1 {mu}m image (CO/CO{sub 2} and dust grains) shows a distribution different from the 2.4 and 3.2 {mu}m images (H{sub 2}O and dust grains). The observed spectrum shows distinct bands at 2.66 and 4.26 {mu}m, attributed to H{sub 2}O and CO{sub 2}, respectively. This is the fifth comet in which CO{sub 2} has been directly detected in the near-infrared spectrum. In addition, CO at 4.67 {mu}m and a broad 3.2-3.6 {mu}m emission band from C-H bearing molecules were detected in the AKARI spectrum. The relative abundance ratios CO{sub 2}/H{sub 2}O and CO/H{sub 2}O derived from the molecular production rates are {approx}4%-5% and <2%, respectively. Comet Lulin belongs to the group that has relatively low abundances of CO and CO{sub 2} among all observed comets.

  16. Dynamic sensor interrogation using wavelength-swept laser with a polygon-scanner-based wavelength filter.

    PubMed

    Kwon, Yong Seok; Ko, Myeong Ock; Jung, Mi Sun; Park, Ik Gon; Kim, Namje; Han, Sang-Pil; Ryu, Han-Cheol; Park, Kyung Hyun; Jeon, Min Yong

    2013-07-29

    We report a high-speed (~2 kHz) dynamic multiplexed fiber Bragg grating (FBG) sensor interrogation using a wavelength-swept laser (WSL) with a polygon-scanner-based wavelength filter. The scanning frequency of the WSL is 18 kHz, and the 10 dB scanning bandwidth is more than 90 nm around a center wavelength of 1,540 nm. The output from the WSL is coupled into the multiplexed FBG array, which consists of five FBGs. The reflected Bragg wavelengths of the FBGs are 1,532.02 nm, 1,537.84 nm, 1,543.48 nm, 1,547.98 nm, and 1,553.06 nm, respectively. A dynamic periodic strain ranging from 500 Hz to 2 kHz is applied to one of the multiplexed FBGs, which is fixed on the stage of the piezoelectric transducer stack. Good dynamic performance of the FBGs and recording of their fast Fourier transform spectra have been successfully achieved with a measuring speed of 18 kHz. The signal-to-noise ratio and the bandwidth over the whole frequency span are determined to be more than 30 dB and around 10 Hz, respectively. We successfully obtained a real-time measurement of the abrupt change of the periodic strain. The dynamic FBG sensor interrogation system can be read out with a WSL for high-speed and high-sensitivity real-time measurement.

  17. Dynamic Sensor Interrogation Using Wavelength-Swept Laser with a Polygon-Scanner-Based Wavelength Filter

    PubMed Central

    Kwon, Yong Seok; Ko, Myeong Ock; Jung, Mi Sun; Park, Ik Gon; Kim, Namje; Han, Sang-Pil; Ryu, Han-Cheol; Park, Kyung Hyun; Jeon, Min Yong

    2013-01-01

    We report a high-speed (∼2 kHz) dynamic multiplexed fiber Bragg grating (FBG) sensor interrogation using a wavelength-swept laser (WSL) with a polygon-scanner-based wavelength filter. The scanning frequency of the WSL is 18 kHz, and the 10 dB scanning bandwidth is more than 90 nm around a center wavelength of 1,540 nm. The output from the WSL is coupled into the multiplexed FBG array, which consists of five FBGs. The reflected Bragg wavelengths of the FBGs are 1,532.02 nm, 1,537.84 nm, 1,543.48 nm, 1,547.98 nm, and 1,553.06 nm, respectively. A dynamic periodic strain ranging from 500 Hz to 2 kHz is applied to one of the multiplexed FBGs, which is fixed on the stage of the piezoelectric transducer stack. Good dynamic performance of the FBGs and recording of their fast Fourier transform spectra have been successfully achieved with a measuring speed of 18 kHz. The signal-to-noise ratio and the bandwidth over the whole frequency span are determined to be more than 30 dB and around 10 Hz, respectively. We successfully obtained a real-time measurement of the abrupt change of the periodic strain. The dynamic FBG sensor interrogation system can be read out with a WSL for high-speed and high-sensitivity real-time measurement. PMID:23899934

  18. Multi-wavelength synchronous pulse burst generation with a wavelength selective switch.

    PubMed

    Roelens, Michaël A; Bolger, Jeremy A; Williams, David; Eggleton, Benjamin J

    2008-07-01

    We demonstrate simultaneous pulse-shaping at different ports of a rapidly tunable wavelength selective switch at a base rate of 40 GHz, based on Fourier-domain pulse shaping. Various pulse bursts are generated and accurately characterized with a linear spectrographic method.

  19. Dynamic sensor interrogation using wavelength-swept laser with a polygon-scanner-based wavelength filter.

    PubMed

    Kwon, Yong Seok; Ko, Myeong Ock; Jung, Mi Sun; Park, Ik Gon; Kim, Namje; Han, Sang-Pil; Ryu, Han-Cheol; Park, Kyung Hyun; Jeon, Min Yong

    2013-01-01

    We report a high-speed (~2 kHz) dynamic multiplexed fiber Bragg grating (FBG) sensor interrogation using a wavelength-swept laser (WSL) with a polygon-scanner-based wavelength filter. The scanning frequency of the WSL is 18 kHz, and the 10 dB scanning bandwidth is more than 90 nm around a center wavelength of 1,540 nm. The output from the WSL is coupled into the multiplexed FBG array, which consists of five FBGs. The reflected Bragg wavelengths of the FBGs are 1,532.02 nm, 1,537.84 nm, 1,543.48 nm, 1,547.98 nm, and 1,553.06 nm, respectively. A dynamic periodic strain ranging from 500 Hz to 2 kHz is applied to one of the multiplexed FBGs, which is fixed on the stage of the piezoelectric transducer stack. Good dynamic performance of the FBGs and recording of their fast Fourier transform spectra have been successfully achieved with a measuring speed of 18 kHz. The signal-to-noise ratio and the bandwidth over the whole frequency span are determined to be more than 30 dB and around 10 Hz, respectively. We successfully obtained a real-time measurement of the abrupt change of the periodic strain. The dynamic FBG sensor interrogation system can be read out with a WSL for high-speed and high-sensitivity real-time measurement. PMID:23899934

  20. Tunable optical tweezers for wavelength-dependent measurements

    PubMed Central

    Hester, Brooke; Campbell, Gretchen K.; López-Mariscal, Carlos; Filgueira, Carly Levin; Huschka, Ryan; Halas, Naomi J.; Helmerson, Kristian

    2012-01-01

    Optical trapping forces depend on the difference between the trap wavelength and the extinction resonances of trapped particles. This leads to a wavelength-dependent trapping force, which should allow for the optimization of optical tweezers systems, simply by choosing the best trapping wavelength for a given application. Here we present an optical tweezer system with wavelength tunability, for the study of resonance effects. With this system, the optical trap stiffness is measured for single trapped particles that exhibit either single or multiple extinction resonances. We include discussions of wavelength-dependent effects, such as changes in temperature, and how to measure them. PMID:22559522

  1. INTERSTELLAR EXTINCTION LAW TOWARD THE GALACTIC CENTER III: J, H, K{sub S} BANDS IN THE 2MASS AND THE MKO SYSTEMS, AND 3.6, 4.5, 5.8, 8.0 {mu}m IN THE SPITZER/IRAC SYSTEM

    SciTech Connect

    Nishiyama, Shogo; Nagata, Tetsuya; Tamura, Motohide; Hatano, Hirofumi; Kato, Daisuke; Tanabe, Toshihiko; Sugitani, Koji

    2009-05-10

    We have determined interstellar extinction law toward the Galactic center (GC) at the wavelength from 1.2 to 8.0 {mu}m, using point sources detected in the IRSF/SIRIUS near-infrared (NIR) survey and those in the Two Micron All Sky Survey (2MASS) and Spitzer/IRAC/GLIMPSE II catalogs. The central region |l | {approx}<3.{sup 0}0 and |b | {approx}<1.{sup 0}0 has been surveyed in the J, H, and K{sub S} bands with the IRSF telescope and the SIRIUS camera whose filters are similar to the Mauna Kea Observatories (MKO) NIR photometric system. Combined with the GLIMPSE II point source catalog, we made K{sub S} versus K{sub S} - {lambda} color-magnitude diagrams (CMDs) where {lambda}=3.6, 4.5, 5.8, and 8.0 {mu}m. The K{sub S} magnitudes of bulge red clump stars and the K{sub S} - {lambda} colors of red giant branches are used as a tracer of the reddening vector in the CMDs. From these magnitudes and colors, we have obtained the ratios of total-to-selective extinction A{sub K{sub S}}/E{sub K{sub S}}{sub -{lambda}} for the four IRAC bands. Combined with A{sub {lambda}}/A{sub K{sub S}} for the J and H bands derived by Nishiyama et al., we obtain A{sub J} :A{sub H} :A{sub K{sub S}}:A {sub [3.6]}:A {sub [4.5]}:A {sub [5.8]}:A {sub [8.0]} = 3.02:1.73:1:0.50:0.39:0.36:0.43 for the line of sight toward the GC. This confirms the flattening of the extinction curve at {lambda} {approx}> 3 {mu}m from a simple extrapolation of the power-law extinction at shorter wavelengths, in accordance with recent studies. The extinction law in the 2MASS J, H, and K{sub S} bands has also been calculated, and good agreement with that in the MKO system is found. Thus, it is established that the extinction in the wavelength range of J, H, and K{sub S} is well fitted by a power law of steep decrease A {sub {lambda}} {proportional_to} {lambda}{sup -2.0} toward the GC. In nearby molecular clouds and diffuse interstellar medium, the lack of reliable measurements of the total-to-selective extinction ratios

  2. Spin and wavelength multiplexed nonlinear metasurface holography

    NASA Astrophysics Data System (ADS)

    Ye, Weimin; Zeuner, Franziska; Li, Xin; Reineke, Bernhard; He, Shan; Qiu, Cheng-Wei; Liu, Juan; Wang, Yongtian; Zhang, Shuang; Zentgraf, Thomas

    2016-06-01

    Metasurfaces, as the ultrathin version of metamaterials, have caught growing attention due to their superior capability in controlling the phase, amplitude and polarization states of light. Among various types of metasurfaces, geometric metasurface that encodes a geometric or Pancharatnam-Berry phase into the orientation angle of the constituent meta-atoms has shown great potential in controlling light in both linear and nonlinear optical regimes. The robust and dispersionless nature of the geometric phase simplifies the wave manipulation tremendously. Benefitting from the continuous phase control, metasurface holography has exhibited advantages over conventional depth controlled holography with discretized phase levels. Here we report on spin and wavelength multiplexed nonlinear metasurface holography, which allows construction of multiple target holographic images carried independently by the fundamental and harmonic generation waves of different spins. The nonlinear holograms provide independent, nondispersive and crosstalk-free post-selective channels for holographic multiplexing and multidimensional optical data storages, anti-counterfeiting, and optical encryption.

  3. Spin and wavelength multiplexed nonlinear metasurface holography

    PubMed Central

    Ye, Weimin; Zeuner, Franziska; Li, Xin; Reineke, Bernhard; He, Shan; Qiu, Cheng-Wei; Liu, Juan; Wang, Yongtian; Zhang, Shuang; Zentgraf, Thomas

    2016-01-01

    Metasurfaces, as the ultrathin version of metamaterials, have caught growing attention due to their superior capability in controlling the phase, amplitude and polarization states of light. Among various types of metasurfaces, geometric metasurface that encodes a geometric or Pancharatnam–Berry phase into the orientation angle of the constituent meta-atoms has shown great potential in controlling light in both linear and nonlinear optical regimes. The robust and dispersionless nature of the geometric phase simplifies the wave manipulation tremendously. Benefitting from the continuous phase control, metasurface holography has exhibited advantages over conventional depth controlled holography with discretized phase levels. Here we report on spin and wavelength multiplexed nonlinear metasurface holography, which allows construction of multiple target holographic images carried independently by the fundamental and harmonic generation waves of different spins. The nonlinear holograms provide independent, nondispersive and crosstalk-free post-selective channels for holographic multiplexing and multidimensional optical data storages, anti-counterfeiting, and optical encryption. PMID:27306147

  4. Achromatic Metasurface Lens at Telecommunication Wavelengths.

    PubMed

    Khorasaninejad, Mohammadreza; Aieta, Francesco; Kanhaiya, Pritpal; Kats, Mikhail A; Genevet, Patrice; Rousso, David; Capasso, Federico

    2015-08-12

    Nanoscale optical resonators enable a new class of flat optical components called metasurfaces. This approach has been used to demonstrate functionalities such as focusing free of monochromatic aberrations (i.e., spherical and coma), anomalous reflection, and large circular dichroism. Recently, dielectric metasurfaces that compensate the phase dispersion responsible for chromatic aberrations have been demonstrated. Here, we utilize an aperiodic array of coupled dielectric nanoresonators to demonstrate a multiwavelength achromatic lens. The focal length remains unchanged for three wavelengths in the near-infrared region (1300, 1550, and 1800 nm). Experimental results are in agreement with full-wave simulations. Our findings are an essential step toward a realization of broadband flat optical elements.

  5. AJ/LPI at millimeter wavelengths

    NASA Astrophysics Data System (ADS)

    Tiffany, G. B.; Bleck, D. T.; Boatman, R. K.

    The AJ/LPI advantages of millimeter wavelength communication at or near the 60-GHz oxygen line have been apparent to researchers for many years. Realizing the full extent of these advantages in a system appropriate for field operation requires more than simply designing a conventional communications link for operation at 60 GHz. Very low sidelobe, narrow beamwidth antennas of rugged construction and the use of frequency agility and spread spectrum modulation are also necessary. Construction of short range, clear weather tactical communication systems exploiting tropospheric oxygen absorption in the 50- to 70-GHz region appears feasible with current state-of-the-art solid-state components. The critical design parameters for achieving all weather jamming resistance and covertness are frequency selection, power management, waveform design, and antenna side- and back-lobe performance.

  6. Spin and wavelength multiplexed nonlinear metasurface holography.

    PubMed

    Ye, Weimin; Zeuner, Franziska; Li, Xin; Reineke, Bernhard; He, Shan; Qiu, Cheng-Wei; Liu, Juan; Wang, Yongtian; Zhang, Shuang; Zentgraf, Thomas

    2016-01-01

    Metasurfaces, as the ultrathin version of metamaterials, have caught growing attention due to their superior capability in controlling the phase, amplitude and polarization states of light. Among various types of metasurfaces, geometric metasurface that encodes a geometric or Pancharatnam-Berry phase into the orientation angle of the constituent meta-atoms has shown great potential in controlling light in both linear and nonlinear optical regimes. The robust and dispersionless nature of the geometric phase simplifies the wave manipulation tremendously. Benefitting from the continuous phase control, metasurface holography has exhibited advantages over conventional depth controlled holography with discretized phase levels. Here we report on spin and wavelength multiplexed nonlinear metasurface holography, which allows construction of multiple target holographic images carried independently by the fundamental and harmonic generation waves of different spins. The nonlinear holograms provide independent, nondispersive and crosstalk-free post-selective channels for holographic multiplexing and multidimensional optical data storages, anti-counterfeiting, and optical encryption. PMID:27306147

  7. Multi-wavelength modeling of protoplanetary disks

    NASA Astrophysics Data System (ADS)

    Pinte, C.; Ménard, F.; Duchêne, G.; Augereau, J.-C.

    2006-06-01

    The on-going revolution of high angular resolution observations and increasing wavelength coverage promises to unlock tightly-kept secrets of circumstellar disks. Thanks to these advances, many issues have already been addressed : large scale geometry of disks, evidence of grain growth, of dust settling, ldots Most of these results are based on models that emphasize on fitting either SEDs or scattered light images or, more recently, interferometric visibilities. In this contribution, we present a global approach which aims at interpreting the increasing amount of observational data coherently, in the framework of a single model, in order to get a more global picture and to better characterize both the dust population and the disk properties. Results of such a modeling approach, applied to a few disks for which large observational data-sets are available, are presented.

  8. Innovative Long Wavelength Infrared Detector Workshop Proceedings

    NASA Technical Reports Server (NTRS)

    Grunthaner, Frank J.

    1990-01-01

    The focus of the workshop was on innovative long wavelength (lambda less than 17 microns) infrared (LWIR) detectors with the potential of meeting future NASA and DoD long-duration space application needs. Requirements are for focal plane arrays which operate near 65K using active refrigeration with mission lifetimes of five to ten years. The workshop addressed innovative concepts, new material systems, novel device physics, and current progress in relation to benchmark technology. It also provided a forum for discussion of performance characterization, producibility, reliability, and fundamental limitations of device physics. It covered the status of the incumbent HgCdTe technology, which shows encouraging progress towards LWIR arrays, and provided a snapshot of research and development in several new contender technologies.

  9. Short-wavelength ablation of solids: pulse duration and wavelength effects

    NASA Astrophysics Data System (ADS)

    Juha, Libor; Bittner, Michal; Chvostova, Dagmar; Letal, Vit; Krasa, Josef; Otcenasek, Zdenek; Kozlova, Michaela; Polan, Jiri; Prag, Ansgar R.; Rus, Bedrich; Stupka, Michal; Krzywinski, Jacek; Andrejczuk, Andrzej; Pelka, Jerzy B.; Sobierajski, Ryszard H.; Ryc, Leszek; Feldhaus, Josef; Boody, Frederick P.; Fiedorowicz, Henryk; Bartnik, Andrzej; Mikolajczyk, Janusz; Rakowski, Rafal; Kubat, P.; Pina, Ladislav; Grisham, Michael E.; Vaschenko, Georgiy O.; Menoni, Carmen S.; Rocca, Jorge J. G.

    2004-11-01

    For conventional wavelength (UV-Vis-IR) lasers delivering radiation energy to the surface of materials, ablation thresholds, ablation (etch) rates, and the quality of ablated structures often differ dramatically between short (typically nanosecond) and ultrashort (typically femtosecond) pulses. Various short-wavelength (l < 100 nm) lasers emitting pulses with durations ranging from ~ 10 fs to ~ 1 ns have recently been put into a routine operation. This makes it possible to investigate how the ablation characteristics depend on the pulse duration in the XUV spectral region. 1.2-ns pulses of 46.9-nm radiation delivered from a capillary-discharge Ne-like Ar laser (Colorado State University, Fort Collins), focused by a spherical Sc/Si multilayer-coated mirror were used for an ablation of organic polymers and silicon. Various materials were irradiated with ellipsoidal-mirror-focused XUV radiation (λ = 86 nm, τ = 30-100 fs) generated by the free-electron laser (FEL) operated at the TESLA Test Facility (TTF1 FEL) in Hamburg. The beam of the Ne-like Zn XUV laser (λ = 21.2 nm, τ < 100 ps) driven by the Prague Asterix Laser System (PALS) was also successfully focused by a spherical Si/Mo multilayer-coated mirror to ablate various materials. Based on the results of the experiments, the etch rates for three different pulse durations are compared using the XUV-ABLATOR code to compensate for the wavelength difference. Comparing the values of etch rates calculated for short pulses with those measured for ultrashort pulses, we can study the influence of pulse duration on XUV ablation efficiency. Ablation efficiencies measured with short pulses at various wavelengths (i.e. 86/46.9/21.2 nm from the above-mentioned lasers and ~ 1 nm from the double stream gas-puff Xe plasma source driven by PALS) show that the wavelength influences the etch rate mainly through the different attenuation lengths.

  10. The effect of track structure on cell inactivation and chromosome damage at a constant let of 120 keV/mum

    NASA Astrophysics Data System (ADS)

    Goodwin, E. H.; Bailey, S. M.; Chen, D. J.; Cornforth, M. N.

    The influence of track structure on chromosome damage and cell inactivation are being investigated. Plateau-phase normal human fibroblast cultures were irradiated with gamma rays, and He, Ne and Ar ions. Particle velocities were chosen so that all beams had an LET of 120 keV/mum. In this constant-LET experimental design, the radial distribution of excitations and ionizations about the particle track is the most significant variable. Using premature chromosome condensation, chromatin breaks were measured at two time points, promptly after irradiation and after a prolonged incubation to allow for repair. These measurements give an indication of both initial chromosomal damage and also residual damage that is either not repaired or is misrepaired. Survival was measured under the same conditions. Results indicate that the RBEs for both cell inactivation and, to a lesser extent, chromosome damage decrease as particle energy increases.

  11. Structural, magnetic, and mechanical properties of 5 {mu}m thick SmCo films suitable for use in microelectromechanical systems

    SciTech Connect

    Walther, A.; Givord, D.; Dempsey, N. M.; Khlopkov, K.; Gutfleisch, O.

    2008-02-15

    5 {mu}m thick SmCo films were deposited onto Si substrates using triode sputtering. A study of the influence of deposition temperature (T{sub dep}{<=}600 deg. C) on the structural, magnetic, and mechanical properties has shown that optimum properties [highest degree of in-plane texture, maximum in-plane coercivity and remanence (1.3 and 0.8 T, respectively), and no film peel-off] are achieved for films deposited at the relatively low temperature of 350 deg. C. This temperature is compatible with film integration into microelectromechanical systems. The deposition rate was increased from 3.6 to 18 {mu}m/h by increasing the surface area of the target from 7 to 81 cm{sup 2} while keeping the target potential fixed. Mechanically intact films could be prepared by deposition onto prepatterned films or deposition through a mask.

  12. Compositional dependence of the 1.8 {mu}m emission properties of Tm{sup 3+} ions in silicate glass

    SciTech Connect

    Wang Xin; Fan Sijun; Li Kefeng; Zhang Lei; Wang Shikai; Hu Lili

    2012-11-15

    The compositional dependence of the 1.8 {mu}m emission properties of Tm{sup 3+} ion-doped lead silicate glasses is investigated. Judd-Ofelt parameters are calculated and their variation with different glass modifier ions is obtained. The Judd-Ofelt parameters increase with decreased modifier ionic radius. A large spontaneous emission probability and a large emission cross-section are found to be related with the strength of the modifier ion. Fluorescence spectra are analyzed using rate equations and compared with recorded data. The results are very close, indicating the reliability of this method. Non-radiative probability is deduced by fitting the fluorescence decay curve; it becomes smaller with increased ionic field strength. Energy transfer processes are studied using the extended overlap integral method.

  13. Broadening and shifting of the methanol 119 {mu}m gain line of linear and circular polarization by collision with chiral molecules

    SciTech Connect

    J.S. Bakos; G. Djotyan; Zsuzsa Soerlei; J. Szigeti; D. K. Mansfield; J. Sarkozi

    2000-06-21

    Evidence of circular dichroism has been observed in the spectral properties of a gas of left-right symmetric molecules. This dichroism comes about as the result of collisions of the symmetric molecules with left-right asymmetric molecules introduced as a buffer gas. In this sense, the dichroism can be said to have been transferred from the chiral buffer molecules to the symmetric, non-chiral molecules of the background vapor. This transferred dichroism appears as broadening in the gain line of the symmetric molecule which is asymmetric with respect to the right or left handedness of a circularly polarized probe. The broadening of the 119 {mu}m line of the methanol molecule was observed using infrared-far infrared double resonance spectroscopy.

  14. Geometrical measurement of cardiac wavelength in reaction-diffusion models

    NASA Astrophysics Data System (ADS)

    Dupraz, Marie; Jacquemet, Vincent

    2014-09-01

    The dynamics of reentrant arrhythmias often consists in multiple wavelets propagating throughout an excitable medium. An arrhythmia can be sustained only if these reentrant waves have a sufficiently short wavelength defined as the distance traveled by the excitation wave during its refractory period. In a uniform medium, wavelength may be estimated as the product of propagation velocity and refractory period (electrophysiological wavelength). In order to accurately measure wavelength in more general substrates relevant to atrial arrhythmias (heterogeneous and anisotropic), we developed a mathematical framework to define geometrical wavelength at each time instant based on the length of streamlines following the propagation velocity field within refractory regions. Two computational methods were implemented: a Lagrangian approach in which a set of streamlines were integrated, and an Eulerian approach in which wavelength was the solution of a partial differential equation. These methods were compared in 1D/2D tissues and in a model of the left atrium. An advantage of geometrical definition of wavelength is that the wavelength of a wavelet can be tracked over time with high temporal resolution and smaller temporal variability in an anisotropic and heterogeneous medium. The results showed that the average electrophysiological wavelength was consistent with geometrical measurements of wavelength. Wavelets were however often shorter than the electrophysiological wavelength due to interactions with boundaries and other wavelets. These tools may help to assess more accurately the relation between substrate properties and wavelet dynamics in computer models.

  15. Use of layer strains in strained-layer superlattices to make devices for operation in new wavelength ranges, E. G. , InAsSb at 8 to 12. mu. m. [InAs/sub 1-x/Sb/sub x/

    DOEpatents

    Osbourn, G.C.

    1983-10-06

    An intrinsic semiconductor electro-optical device comprises a p-n junction intrinsically responsive, when cooled, to electromagnetic radiation in the wavelength range of 8 to 12 ..mu..m. This radiation responsive p-n junction comprises a strained-layer superlattice (SLS) of alternating layers of two different III-V semiconductors. The lattice constants of the two semiconductors are mismatched, whereby a total strain is imposed on each pair of alternating semiconductor layers in the SLS structure, the proportion of the total strain which acts on each layer of the pair being proportional to the ratio of the layer thicknesses of each layer in the pair.

  16. THE 1.6 {mu}m NEAR-INFRARED NUCLEI OF 3C RADIO GALAXIES: JETS, THERMAL EMISSION, OR SCATTERED LIGHT?

    SciTech Connect

    Baldi, Ranieri D.; Chiaberge, Marco; Sparks, William; Macchetto, F. Duccio; Capetti, Alessandro; O'Dea, Christopher P.; Axon, David J.; Baum, Stefi A.; Quillen, Alice C.

    2010-12-20

    Using HST NICMOS 2 observations we have measured 1.6 {mu}m near-infrared nuclear luminosities of 100 3CR radio galaxies with z < 0.3, by modeling and subtracting the extended emission from the host galaxy. We performed a multiwavelength statistical analysis (including optical and radio data) of the properties of the nuclei following classification of the objects into FR I and FR II, and low-ionization galaxies (LIGs), high-ionization galaxies (HIGs), and broad-line objects (BLOs) using the radio morphology and optical spectra, respectively. The correlations among near-infrared, optical, and radio nuclear luminosity support the idea that the near-infrared nuclear emission of FR Is has a non-thermal origin. Despite the difference in radio morphology, the multiwavelength properties of FR II LIG nuclei are statistically indistinguishable from those of FR Is, an indication of a common structure of the central engine. All BLOs show an unresolved near-infrared nucleus and a large near-infrared excess with respect to FR II LIGs and FR Is of equal radio core luminosity. This requires the presence of an additional (and dominant) component other than the non-thermal light. Considering the shape of their spectral energy distribution, we ascribe the origin of their near-infrared light to hot circumnuclear dust. A near-infrared excess is also found in HIGs, but their nuclei are substantially fainter than those of BLO. This result indicates that substantial obscuration along the line of sight to the nuclei is still present at 1.6 {mu}m. Nonetheless, HIG nuclei cannot simply be explained in terms of dust obscuration: a significant contribution from light reflected in a circumnuclear scattering region is needed to account for their multiwavelength properties.

  17. WISE TF: A MID-INFRARED, 3.4 {mu}m EXTENSION OF THE TULLY-FISHER RELATION USING WISE PHOTOMETRY

    SciTech Connect

    Lagattuta, David J.; Mould, Jeremy R.; Staveley-Smith, Lister; Hong Tao; Springob, Christopher M.; Masters, Karen L.; Koribalski, Baerbel S.; Jones, D. Heath

    2013-07-10

    We present a mid-infrared Tully-Fisher (TF) relation using photometry from the 3.4 {mu}m W1 band of the Wide-field Infrared Survey Explorer (WISE) satellite. The WISE TF relation is formed from 568 galaxies taken from the all-sky 2MASS Tully-Fisher (2MTF) galaxy catalog, spanning a range of environments including field, group, and cluster galaxies. This constitutes the largest mid-infrared TF relation constructed to date. After applying a number of corrections to galaxy magnitudes and line widths, we measure a master TF relation given by M{sub corr} = -22.24 - 10.05[log (W{sub corr}) - 2.5], with an average dispersion of {sigma}{sub WISE} = 0.686 mag. There is some tension between WISE TF and a preliminary 3.6 {mu}m relation, which has a shallower slope and almost no intrinsic dispersion. However, our results agree well with a more recent relation constructed from a large sample of cluster galaxies. We additionally compare WISE TF to the near-infrared 2MTF template relations, finding a good agreement between the TF parameters and total dispersions of WISE TF and the 2MTF K-band template. This fact, coupled with typical galaxy colors of (K - W1) {approx} 0, suggests that these two bands are tracing similar stellar populations, including the older, centrally-located stars in the galactic bulge which can (for galaxies with a prominent bulge) dominate the light profile.

  18. Transversal wavelength-independent microradiography, a method for monitoring caries lesions over time, validated with transversal microradiography.

    PubMed

    Thomas, R Z; Ruben, J L; de Vries, J; ten Bosch, J J; Huysmans, M C D N J M

    2006-01-01

    This paper describes a microradiographic method for measuring mineral concentration in a transversal geometry with thick (< or =3.2 mm) sections: transversal wavelength-independent microradiography (T-WIM). It was tested on bovine enamel and dentin samples in vitro, and the results were validated with those of transversal microradiography (TMR). 48 enamel and 48 dentin samples (3.2 x 3.2 x 1.5 mm) were embedded in acrylic resin, randomly divided into six groups of 8 dentin or 8 enamel samples, and demineralized for 0 (sound control), 1, 2, 3, 4, or 5 weeks. For T-WIM, samples were imaged on film with polychromatic 40-kV Cu X-rays with an Al (0.25 mm)/Ni (0.02 mm) filter together with an aluminium/zinc step wedge. TMR slices (about 80 mum for enamel and about 130 mum for dentine) were subsequently cut from the centre of the samples and subjected to TMR. Microradiographs from both methods were digitized and image analysis software was used to calculate lesion depth and mineral loss. The relations between T-WIM and TMR results for mineral loss (DeltaZ) and lesion depth were nearly linear (r > or = 0.96) for both enamel and dentin. The slopes of the regression lines were between 0.99 and 1.02 except for DeltaZ in dentine, which was 0.89. It was concluded that T-WIM is a suitable method for TMR on thick samples. PMID:16741358

  19. Wire grid polarizers for visible wavelengths

    NASA Astrophysics Data System (ADS)

    Johnson, Joshua Hans

    Detailed analysis of wire-grid (WG) polarizers for visible wavelengths is presented. Rigorous coupled-wave analysis (RCWA) is used to model their performance. The optimum choice of metal for the wires is identified, and the effects of different substrate indices of refraction are considered. The polarization properties are considered with changes in the physical parameters, including period, duty cycle, and wire thickness. It is shown that the performance of WG polarizers improves with increasing angle of incidence. The effect of non-square wire profiles is considered, as is the effect of adding additional dielectric layers between the wires and the substrate. The effect of metal oxide layers forming on the wires is also modeled. While most of this work concerns WG polarizers used in transmission, the performance in reflection is also discussed. Several visible-wavelength WG polarizers were fabricated at the Cornell Nanofabrication Facility (CNF) in Ithaca, NY. Electron-beam lithography was used to write the patterns for these devices, and two different methods of pattern transfer were compared. These were the lift-off method and reactive-ion etching (RIE). We found that lift-off could not produce wires thick enough for good polarization properties. RIE could produce much thicker wires with good profiles and was used for all of the experimental work presented here. Two different methods for metal film deposition, evaporation and sputtering were also compared. Films deposited by sputtering were found to have much lower indices of refraction and to not respond to etching as well. Thermally evaporated films performed much better in WG polarizers. Alternative methods for the mass-production of visible-wavelength WG polarizers are also discussed. The performance of the fabricated WG polarizers is compared to theory. When the measured physical parameters are used in RCWA to predict the performance, the measured extinction ratio is found to be much lower than the

  20. Multi-wavelength characterization of carbonaceous aerosol

    NASA Astrophysics Data System (ADS)

    Massabò, Dario; Caponi, Lorenzo; Chiara Bove, Maria; Piazzalunga, Andrea; Valli, Gianluigi; Vecchi, Roberta; Prati, Paolo

    2014-05-01

    Carbonaceous aerosol is a major component of the urban PM. It mainly consists of organic carbon (OC) and elemental carbon (EC) although a minor fraction of carbonate carbon could be also present. Elemental carbon is mainly found in the finer PM fractions (PM2.5 and PM1) and it is strongly light absorbing. When determined by optical methods, it is usually called black carbon (BC). The two quantities, EC and BC, even if both related to the refractory components of carbonaceous aerosols, do not exactly define the same PM component (Bond and Bergstrom, 2006; and references therein). Moreover, another fraction of light-absorbing carbon exists which is not black and it is generally called brown carbon (Andreae and Gelencsér, 2006). We introduce a simple, fully automatic, multi-wavelength and non-destructive optical system, actually a Multi-Wavelength Absorbance Analyzer, MWAA, to measure off-line the light absorption in Particulate Matter (PM) collected on filters and hence to derive the black and brown carbon content in the PM This gives the opportunity to measure in the same sample the concentration of total PM by gravimetric analysis, black and brown carbon, metals by, for instance, X Ray Fluorescence, and finally ions by Ion Chromatography. Up to 16 samples can be analyzed in sequence and in an automatic and controlled way within a few hours. The filter absorbance measured by MWAA was successfully validated both against a MAAP, Multi Angle Absorption Photometer (Petzold and Schönlinner, 2004), and the polar photometer of the University of Milan. The measurement of sample absorbance at three wavelengths gives the possibility to apportion different sources of carbonaceous PM, for instance fossil fuels and wood combustion. This can be done following the so called "aethalometer method" (Sandradewi et al., 2008;) but with some significant upgrades that will be discussed together the results of field campaigns in rural and urban sites. Andreae, M.O, and Gelencsér, A

  1. Dual-wavelength diode laser with electrically adjustable wavelength distance at 785  nm.

    PubMed

    Sumpf, Bernd; Kabitzke, Julia; Fricke, Jörg; Ressel, Peter; Müller, André; Maiwald, Martin; Tränkle, Günther

    2016-08-15

    A spectrally adjustable monolithic dual-wavelength diode laser at 785 nm as an excitation light source for shifted excitation Raman difference spectroscopy (SERDS) is presented. The spectral distance between the two excitation wavelengths can be electrically adjusted between 0 and 2.0 nm using implemented heater elements above the distributed Bragg reflector (DBR) gratings. Output powers up to 180 mW at a temperature of 25°C were measured. The spectral width is smaller than 13 pm, limited by the spectrum analyzer. The device is well-suited for Raman spectroscopy, and the flexible spectral distance allows a target-specific adjustment of the excitation light source for shifted excitation Raman difference spectroscopy (SERDS). PMID:27519065

  2. Composite multiple wavelength laser material and multiple wavelength laser for use therewith

    NASA Technical Reports Server (NTRS)

    Jani, Mahendra G. (Inventor)

    1997-01-01

    A composite multiple wavelength laser material is provided and is typically constructed with a common axis of construction in the form of a rod of uniform cross-section. The rod comprises a plurality of segments of laser material bonded, e.g., diffusion bonded, to one another along the common axis. Each segment lases at a unique wavelength when excited to produce a laser emission. The segments can be made from a birefringent material doped with laser active ions. If the same birefringent host material is used for all segments, ground-state absorption losses can be reduced by terminating either end of the rod with end segments made from undoped pieces of the birefringent material.

  3. Alerting effects of short-wavelength (blue) and long-wavelength (red) lights in the afternoon.

    PubMed

    Sahin, Levent; Figueiro, Mariana G

    2013-05-27

    Light has an acute effect on neuroendocrine responses, performance, and alertness. Most studies to date have linked the alerting effects of light to its ability to suppress melatonin, which is maximally sensitive to short-wavelength light. Recent studies, however, have shown alerting effects of white or narrowband short-wavelength lights during daytime, when melatonin levels are low. While the use of light at night to promote alertness is well understood, it is important to develop an understanding of how light impacts alertness during the daytime, especially during the post-lunch hours. The aim of the current study was to investigate how 48-minute exposures to short-wavelength (blue) light (40 lux, 18.9 microWatts/cm(2) λ(max) = 470 nanometers [nm]) or long-wavelength (red) light (40 lux, 18.9 microWatts/cm(2) λ(max) = 630 nm) close to the post-lunch dip hours affect electroencephalogram measures in participants with regular sleep schedules. Power in the alpha, alpha theta, and theta ranges was significantly lower (p<0.05) after participants were exposed to red light than after they remained in darkness. Exposure to blue light reduced alpha and alpha theta power compared to darkness, but these differences did not reach statistical significance (p>0.05). The present results extend those performed during the nighttime, and demonstrate that light can be used to increase alertness in the afternoon, close to the post-lunch dip hours. These results also suggest that acute melatonin suppression is not needed to elicit an alerting effect in humans. PMID:23535242

  4. A new algorithm for optimizing the wavelength coverage for spectroscopic studies: Spectral Wavelength Optimization Code (SWOC)

    NASA Astrophysics Data System (ADS)

    Ruchti, G. R.; Feltzing, S.; Lind, K.; Caffau, E.; Korn, A. J.; Schnurr, O.; Hansen, C. J.; Koch, A.; Sbordone, L.; de Jong, R. S.

    2016-09-01

    The past decade and a half has seen the design and execution of several ground-based spectroscopic surveys, both Galactic and Extragalactic. Additionally, new surveys are being designed that extend the boundaries of current surveys. In this context, many important considerations must be done when designing a spectrograph for the future. Among these is the determination of the optimum wavelength coverage. In this work, we present a new code for determining the wavelength ranges that provide the optimal amount of information to achieve the required science goals for a given survey. In its first mode, it utilizes a user-defined list of spectral features to compute a figure-of-merit for different spectral configurations. The second mode utilizes a set of flux-calibrated spectra, determining the spectral regions that show the largest differences among the spectra. Our algorithm is easily adaptable for any set of science requirements and any spectrograph design. We apply the algorithm to several examples, including 4MOST, showing the method yields important design constraints to the wavelength regions.

  5. Early Results from the Long Wavelength Array

    NASA Astrophysics Data System (ADS)

    Taylor, Gregory B.; LWA Collaboration

    2012-01-01

    The Long Wavelength Array (LWA) will be a new multi-purpose radio telescope operating in the frequency range 10-88 MHz. Scientific programs include pulsars, supernova remnants, general transient searches, radio recombination lines, solar and Jupiter bursts, investigations into the "dark ages" using redshifted hydrogen, and ionospheric phenomena. Upon completion, LWA will consist of 53 phased array "stations” distributed accross a region over 400 km in diameter. Each station consists of 256 pairs of dipole-type antennas whose signals are formed into beams, with outputs transported to a central location for high-resolution aperture synthesis imaging. The resulting image sensitivity is estimated to be a few mJy (5sigma, 8 MHz, 2 polarizations, 1 h, zenith) from 20-80 MHz; with angular resolution of a few arcseconds. Additional information is online at http://lwa.unm.edu. Partners in the LWA project include LANL, JPL, NRAO, NRL, UNM, NMT, and Virginia Tech. The first station of the LWA, called "LWA1", is located near the center of the EVLA and has recently begun scientific operations. The LWA1 images the sky in realtime using the "transient buffer - narrowband” (TBN) system which is operational with 257 dipoles, and a bandwidth of 70 kHz. The LWA1 can also form up to 4 beams on the sky simultaneously with 16 MHz bandwidth in each of two tuning and full polarization. Early results include observations of pulsars, the Sun, and Jupiter.

  6. Array of Bolometers for Submillimeter- Wavelength Operation

    NASA Technical Reports Server (NTRS)

    Bock, James; Turner, Anthony

    2007-01-01

    A feed-horn-coupled monolithic array of micromesh bolometers is undergoing development for use in a photometric camera. The array is designed for conducting astrophysical observations in a wavelength band centered at 350 m. The bolometers are improved versions of previously developed bolometers comprising metalized Si3N4 micromesh radiation absorbers coupled with neutron- transmutation-doped Ge thermistors. Incident radiation heats the absorbers above a base temperature, changing the electrical resistance of each thermistor. In the present array of improved bolometers (see figure), the thermistors are attached to the micromesh absorbers by indium bump bonds and are addressed by use of lithographed, vapor-deposited electrical leads. This architecture reduces the heat capacity and minimizes the thermal conductivity to 1/20 and 1/300, respectively, of earlier versions of these detectors, with consequent improvement in sensitivity and speed of response. The micromesh bolometers, intended to operate under an optical background set by thermal emission from an ambient-temperature space-borne telescope, are designed such that the random arrival of photons ("photon noise") dominates the noise sources arising from the detector and readout electronics. The micromesh is designed to be a highly thermally and optically efficient absorber with a limiting response time of about 100 s. The absorber and thermistor heat capacity are minimized in order to give rapid speed of response. Due to the minimization of the absorber volume, the dominant source of heat capacity arises from the thermistor.

  7. Random-phase metasurfaces at optical wavelengths

    NASA Astrophysics Data System (ADS)

    Pors, Anders; Ding, Fei; Chen, Yiting; Radko, Ilya P.; Bozhevolnyi, Sergey I.

    2016-06-01

    Random-phase metasurfaces, in which the constituents scatter light with random phases, have the property that an incident plane wave will diffusely scatter, hereby leading to a complex far-field response that is most suitably described by statistical means. In this work, we present and exemplify the statistical description of the far-field response, particularly highlighting how the response for polarised and unpolarised light might be alike or different depending on the correlation of scattering phases for two orthogonal polarisations. By utilizing gap plasmon-based metasurfaces, consisting of an optically thick gold film overlaid by a subwavelength thin glass spacer and an array of gold nanobricks, we design and realize random-phase metasurfaces at a wavelength of 800 nm. Optical characterisation of the fabricated samples convincingly demonstrates the diffuse scattering of reflected light, with statistics obeying the theoretical predictions. We foresee the use of random-phase metasurfaces for camouflage applications and as high-quality reference structures in dark-field microscopy, while the control of the statistics for polarised and unpolarised light might find usage in security applications. Finally, by incorporating a certain correlation between scattering by neighbouring metasurface constituents new types of functionalities can be realised, such as a Lambertian reflector.

  8. Random-phase metasurfaces at optical wavelengths

    PubMed Central

    Pors, Anders; Ding, Fei; Chen, Yiting; Radko, Ilya P.; Bozhevolnyi, Sergey I.

    2016-01-01

    Random-phase metasurfaces, in which the constituents scatter light with random phases, have the property that an incident plane wave will diffusely scatter, hereby leading to a complex far-field response that is most suitably described by statistical means. In this work, we present and exemplify the statistical description of the far-field response, particularly highlighting how the response for polarised and unpolarised light might be alike or different depending on the correlation of scattering phases for two orthogonal polarisations. By utilizing gap plasmon-based metasurfaces, consisting of an optically thick gold film overlaid by a subwavelength thin glass spacer and an array of gold nanobricks, we design and realize random-phase metasurfaces at a wavelength of 800 nm. Optical characterisation of the fabricated samples convincingly demonstrates the diffuse scattering of reflected light, with statistics obeying the theoretical predictions. We foresee the use of random-phase metasurfaces for camouflage applications and as high-quality reference structures in dark-field microscopy, while the control of the statistics for polarised and unpolarised light might find usage in security applications. Finally, by incorporating a certain correlation between scattering by neighbouring metasurface constituents new types of functionalities can be realised, such as a Lambertian reflector. PMID:27328635

  9. Random-phase metasurfaces at optical wavelengths.

    PubMed

    Pors, Anders; Ding, Fei; Chen, Yiting; Radko, Ilya P; Bozhevolnyi, Sergey I

    2016-01-01

    Random-phase metasurfaces, in which the constituents scatter light with random phases, have the property that an incident plane wave will diffusely scatter, hereby leading to a complex far-field response that is most suitably described by statistical means. In this work, we present and exemplify the statistical description of the far-field response, particularly highlighting how the response for polarised and unpolarised light might be alike or different depending on the correlation of scattering phases for two orthogonal polarisations. By utilizing gap plasmon-based metasurfaces, consisting of an optically thick gold film overlaid by a subwavelength thin glass spacer and an array of gold nanobricks, we design and realize random-phase metasurfaces at a wavelength of 800 nm. Optical characterisation of the fabricated samples convincingly demonstrates the diffuse scattering of reflected light, with statistics obeying the theoretical predictions. We foresee the use of random-phase metasurfaces for camouflage applications and as high-quality reference structures in dark-field microscopy, while the control of the statistics for polarised and unpolarised light might find usage in security applications. Finally, by incorporating a certain correlation between scattering by neighbouring metasurface constituents new types of functionalities can be realised, such as a Lambertian reflector. PMID:27328635

  10. Visible-wavelength semiconductor lasers and arrays

    DOEpatents

    Schneider, R.P. Jr.; Crawford, M.H.

    1996-09-17

    The visible semiconductor laser includes an InAlGaP active region surrounded by one or more AlGaAs layers on each side, with carbon as the sole p-type dopant. Embodiments of the invention are provided as vertical-cavity surface-emitting lasers (VCSELs) and as edge-emitting lasers (EELs). One or more transition layers comprised of a substantially indium-free semiconductor alloy such as AlAsP, AlGaAsP, or the like may be provided between the InAlGaP active region and the AlGaAS DBR mirrors or confinement layers to improve carrier injection and device efficiency by reducing any band offsets. Visible VCSEL devices fabricated according to the invention with a one-wavelength-thick (1{lambda}) optical cavity operate continuous-wave (cw) with lasing output powers up to 8 mW, and a peak power conversion efficiency of up to 11%. 5 figs.

  11. Visible-wavelength semiconductor lasers and arrays

    DOEpatents

    Schneider, Jr., Richard P.; Crawford, Mary H.

    1996-01-01

    A visible semiconductor laser. The visible semiconductor laser includes an InAlGaP active region surrounded by one or more AlGaAs layers on each side, with carbon as the sole p-type dopant. Embodiments of the invention are provided as vertical-cavity surface-emitting lasers (VCSELs) and as edge-emitting lasers (EELs). One or more transition layers comprised of a substantially indium-free semiconductor alloy such as AlAsP, AlGaAsP, or the like may be provided between the InAlGaP active region and the AlGaAS DBR mirrors or confinement layers to improve carrier injection and device efficiency by reducing any band offsets. Visible VCSEL devices fabricated according to the invention with a one-wavelength-thick (1.lambda.) optical cavity operate continuous-wave (cw) with lasing output powers up to 8 mW, and a peak power conversion efficiency of up to 11%.

  12. Patrolling the Sky at Long Wavelengths

    NASA Astrophysics Data System (ADS)

    Taylor, Gregory B.; Obenberger, K.; Hartman, J.; LWA Collaboration

    2013-01-01

    The first station of the Long Wavelength Array, “LWA1”, is located near the center of the Very Large Array in central New Mexico and has recently begun scientific operations as a stand-alone instrument with collecting area roughly equivalent to a 100m dish. The LWA1 images the sky in near-real-time using the “transient buffer - narrowband” (TBN) system which is operational with 258 dipoles, and a bandwidth of 70 kHz. This bandwidth can be placed at any frequency between 5 and 88 MHz. Near-real-time reduction of the data is accomplished by a dedicated cluster in the electronics shelter of the array. The LWA1 can also form up to 4 beams on the sky simultaneously with 16 MHz bandwidth in each of two tunings and full polarization which can provide higher senstivity for follow-up observations. Here we report on detection limits for prompt emission from approximately 30 Gamma-Ray Bursts at frequencies between 30 and 80 MHz. We also report on a number of bright transients of short duration that were detected in the course of searching the error-boxes of GRBs. Support for operations and continuing development of the LWA1 is provided by the National Science Foundation under grant AST-1139974 of the University Radio Observatory program.

  13. Design of wavelength-selective waveplates using genetic algorithm

    NASA Astrophysics Data System (ADS)

    Katayama, Ryuichi

    2013-03-01

    Wavelength-selective waveplates, which act either identically or differently for plural wavelengths, are useful for optical systems that handle plural wavelengths. However, they cannot be analytically designed because of the complexity of their structure. Genetic algorithm is one of the methods for solving optimization problems and is used for several kinds of optical design (e.g., design of thin films, diffractive optical elements, and lenses). I considered that it is effective for designing wavelength-selective waveplates also and tried to design them using the genetic algorithm for the first time to the best of my knowledge. As a result, four types of wavelength-selective waveplate for three wavelengths (405, 650, and 780 nm) were successfully designed. These waveplates are useful for Blu-ray Disc/Digital Versatile Disc/Compact Disc compatible optical pickups.

  14. Measurement of Magic Wavelengths for the ^{40}Ca^{+} Clock Transition.

    PubMed

    Liu, Pei-Liang; Huang, Yao; Bian, Wu; Shao, Hu; Guan, Hua; Tang, Yong-Bo; Li, Cheng-Bin; Mitroy, J; Gao, Ke-Lin

    2015-06-01

    We demonstrate experimentally the existence of magic wavelengths and determine the ratio of oscillator strengths for a single trapped ion. For the first time, two magic wavelengths near 396 nm for the ^{40}Ca^{+} clock transition are measured simultaneously with high precision. By tuning the applied laser to an intermediate wavelength between transitions 4s_{1/2}→4p_{1/2} and 4s_{1/2}→4p_{3/2}, the sensitivity of the clock transition Stark shift to the oscillator strengths is greatly enhanced. Furthermore, with the measured magic wavelengths, we determine the ratio of the oscillator strengths with a deviation of less than 0.5%. Our experimental method may be applied to measure magic wavelengths for other ion clock transitions. Promisingly, the measurement of these magic wavelengths paves the way to building all-optical trapped ion clocks. PMID:26196619

  15. Broadband Wavelength Spanning Holographic Polymer Dispersed Liquid Crystals

    NASA Astrophysics Data System (ADS)

    Rai, Kashma; Shriyan, Sameet; Fontecchio, Adam

    2008-03-01

    Broadened interaction wavelength of holographic polymer dispersed liquid crystals (HPDLCs) have extensive applications in beam steering for instrument clusters, hyperspectral imaging, wavelength filtering and construction of lightweight optics. A novel simultaneous time and spatial multiplexing formation configuration is proposed here, to increase narrow wavelength reflecting notch to broad range wavelength spanning device. HPDLC films have electro-optic controllability by applying field. No moving parts, light weight, small footprint compared to prisms and lenses, high color purity make the broadband wavelength HPDLCs desirable for the above applications. Varying the incident laser beam exposure angles using motorized rotating stage, during formation is the key step here for their formation in a single medium. The fabricated broadband wavelength sensitive HPDLCs are characterized for the uniformity of the reflected peak and electro optic response. Their output wavefront is analyzed using wavefront analysis technique.

  16. Measurement of Magic Wavelengths for the ^{40}Ca^{+} Clock Transition.

    PubMed

    Liu, Pei-Liang; Huang, Yao; Bian, Wu; Shao, Hu; Guan, Hua; Tang, Yong-Bo; Li, Cheng-Bin; Mitroy, J; Gao, Ke-Lin

    2015-06-01

    We demonstrate experimentally the existence of magic wavelengths and determine the ratio of oscillator strengths for a single trapped ion. For the first time, two magic wavelengths near 396 nm for the ^{40}Ca^{+} clock transition are measured simultaneously with high precision. By tuning the applied laser to an intermediate wavelength between transitions 4s_{1/2}→4p_{1/2} and 4s_{1/2}→4p_{3/2}, the sensitivity of the clock transition Stark shift to the oscillator strengths is greatly enhanced. Furthermore, with the measured magic wavelengths, we determine the ratio of the oscillator strengths with a deviation of less than 0.5%. Our experimental method may be applied to measure magic wavelengths for other ion clock transitions. Promisingly, the measurement of these magic wavelengths paves the way to building all-optical trapped ion clocks.

  17. Identification of aerosol composition from multi-wavelength lidar measurements

    NASA Technical Reports Server (NTRS)

    Wood, S. A.

    1984-01-01

    This paper seeks to develop the potential of lidar for the identification of the chemical composition of atmospheric aerosols. Available numerical computations suggest that aerosols can be identified by the wavelength dependence of aerosol optical properties. Since lidar can derive the volume backscatter coefficient as a function of wavelength, a multi-wavelength lidar system may be able to provide valuable information on the composition of aerosols. This research theoretically investigates the volume backscatter coefficients for the aerosol classes, sea-salts, and sulfates, as a function of wavelength. The results show that these aerosol compositions can be characterized and identified by their backscatter wavelength dependence. A method to utilize multi-wavelength lidar measurements to discriminate between compositionally different thin aerosol layers is discussed.

  18. Reference wavelength method for a two-color pyrometer.

    PubMed

    Hahn, J W; Rhee, C

    1987-12-15

    The reference wavelength method is used for a two-color pyrometer and, with the reference wavelength method, an analytical formula of the ratio temperature for the two-color pyrometer is derived. For one channel of the two-color pyrometer, with a triangular spectral response of 0.1-micro m FWHM and 2.0-micro m peak wavelength, the effective wavelength and the correction factors with several reference wavelengths are determined. By fitting the curves of the effective wavelength and the correction factor to simple functional forms of temperature, the radiance errors for both cases are calculated. Also, it is found that the correction factor determined in a single-color pyrometer can be used directly in one channel of the two-color pyrometer without additional calculation. PMID:20523516

  19. FIRST LIGHT LBT AO IMAGES OF HR 8799 bcde AT 1.6 AND 3.3 {mu}m: NEW DISCREPANCIES BETWEEN YOUNG PLANETS AND OLD BROWN DWARFS

    SciTech Connect

    Skemer, Andrew J.; Hinz, Philip M.; Rodigas, Timothy J.; Close, Laird; McCarthy, Don; Kulesa, Craig; Apai, Daniel; Bailey, Vanessa; Esposito, Simone; Arcidiacono, Carmelo; Mannucci, Filippo; Agapito, Guido; Argomedo, Javier; Briguglio, Runa; Burrows, Adam; Leisenring, Jarron; Skrutskie, Michael; Desidera, Silvano; Mesa, Dino; Boutsia, Konstantina; and others

    2012-07-01

    As the only directly imaged multiple planet system, HR 8799 provides a unique opportunity to study the physical properties of several planets in parallel. In this paper, we image all four of the HR 8799 planets at H band and 3.3 {mu}m with the new Large Binocular Telescope adaptive optics system, PISCES, and LBTI/LMIRCam. Our images offer an unprecedented view of the system, allowing us to obtain H and 3.3 {mu}m photometry of the innermost planet (for the first time) and put strong upper limits on the presence of a hypothetical fifth companion. We find that all four planets are unexpectedly bright at 3.3 {mu}m compared to the equilibrium chemistry models used for field brown dwarfs, which predict that planets should be faint at 3.3 {mu}m due to CH{sub 4} opacity. We attempt to model the planets with thick-cloudy, non-equilibrium chemistry atmospheres but find that removing CH{sub 4} to fit the 3.3 {mu}m photometry increases the predicted L' (3.8 {mu}m) flux enough that it is inconsistent with observations. In an effort to fit the spectral energy distribution of the HR 8799 planets, we construct mixtures of cloudy atmospheres, which are intended to represent planets covered by clouds of varying opacity. In this scenario, regions with low opacity look hot and bright, while regions with high opacity look faint, similar to the patchy cloud structures on Jupiter and L/T transition brown dwarfs. Our mixed-cloud models reproduce all of the available data, but self-consistent models are still necessary to demonstrate their viability.

  20. Annealing studies of heteroepitaxial InSbN on GaAs grown by molecular beam epitaxy for long-wavelength infrared detectors

    SciTech Connect

    Patra, Nimai C.; Bharatan, Sudhakar; Li Jia; Iyer, Shanthi

    2012-10-15

    We report the effect of annealing on the structural, vibrational, electrical, and optical properties of heteropepitaxially grown InSbN epilayers on GaAs substrate by molecular beam epitaxy for long-wavelength infrared detector applications. As-grown epilayers exhibited high N incorporation in the both substitutional and interstitial sites, with N induced defects as evidenced from high resolution x-ray diffraction, secondary ion mass spectroscopy, and room temperature (RT) micro-Raman studies. The as-grown optical band gap was observed at 0.132 eV ({approx}9.4 {mu}m) and the epilayer exhibited high background carrier concentration at {approx}10{sup 18} cm{sup -3} range with corresponding mobility of {approx}10{sup 3} cm{sup 2}/Vs. Ex situ and in situ annealing at 430 Degree-Sign C though led to the loss of N but improved InSb quality due to effective annihilation of N related defects and other lattice defects attested to enhanced InSb LO phonon modes in the corresponding Raman spectra. Further, annealing resulted in the optical absorption edge red shifting to 0.12 eV ({approx}10.3 {mu}m) and the layers were characterized by reduced background carrier concentration in the {approx}10{sup 16} cm{sup -3} range with enhanced mobility in {approx}10{sup 4} cm{sup 2}/Vs range.

  1. GHRS Ech-B Wavelength Monitor -- Cycle 4

    NASA Astrophysics Data System (ADS)

    Soderblom, David

    1994-01-01

    This proposal defines the spectral lamp test for Echelle B. It is an internal test which makes measurements of the wavelength lamp SC2. It calibrates the carrousel function, Y deflections, resolving power, sensitivity, and scattered light. The wavelength calibration dispersion constants will be updated in the PODPS calibration data base. It will be run every 4 months. The wavelengths may be out of range according to PEPSI or TRANS. Please ignore the errors.

  2. Holographic topography using acousto-optically generated large synthetic wavelengths

    NASA Astrophysics Data System (ADS)

    Abeywickrema, U.; Beamer, D.; Banerjee, P.; Poon, T.-C.

    2016-03-01

    Digital holography uses phase imaging in a variety of techniques to produce a three-dimensional phase resolved image that includes accurate depth information about the object of interest. Multi-wavelength digital holography is an accurate method for measuring the topography of surfaces. Typically, the object phases are reconstructed for two wavelengths separately and the phase corresponding to the synthetic wavelength (obtained from the two wavelengths) is obtained by calculating the phase difference. Then the surface map can be obtained using proper phase-unwrapping techniques. Usually these synthetic wavelengths are on the order of microns which can be used to resolve depths on the order of microns. In this work, two extremely close wavelengths generated by an acousto-optic modulator (AOM) are used to perform two-wavelength digital holography. Since the difference between the two wavelengths is on the order of picometers, a large synthetic wavelength (on the order of centimeters) can be obtained which can be used to determine the topography of macroscopic surface features. Also since the synthetic wavelength is large, an accurate surface map can be obtained without using a phase-unwrapping technique. A 514 nm Argon-ion laser is used as the optical source, and used with an AOM to generate the zeroth-order and frequency-shifted first-order diffracted orders which are used as the two wavelengths. Both beams are aligned through the same spatial filter assembly. Holograms are captured sequentially using a typical Mach-Zehnder interferometric setup by blocking one beam at a time. Limitations of the large synthetic wavelength are also discussed.

  3. Wavelength encoding technique for particle analyses in hematology analyzer

    NASA Astrophysics Data System (ADS)

    Rongeat, Nelly; Brunel, Patrick; Gineys, Jean-Philippe; Cremien, Didier; Couderc, Vincent; Nérin, Philippe

    2011-07-01

    The aim of this study is to combine multiple excitation wavelengths in order to improve accuracy of fluorescence characterization of labeled cells. The experimental demonstration is realized with a hematology analyzer based on flow cytometry and a CW laser source emitting two visible wavelengths. A given optical encoding associated to each wavelength allows fluorescence identification coming from specific fluorochromes and avoiding the use of noisy compensation method.

  4. Picosecond Surface Acoustic Waves Using A Suboptical Wavelength Absorption Grating

    SciTech Connect

    Hurley, David Howard; Telschow, Kenneth Louis

    2002-10-01

    We have demonstrated laser generation and detection of Rayleigh surface acoustic waves (SAW’s) with acoustic wavelengths that are smaller than the optical wavelength of both the excitation and the detection beams. SAW generation was achieved using electron beam lithography to modulate the surface reflectivity and hence the lateral thermal gradients on a suboptical wavelength scale. The generation and detection characteristics of two material systems were investigated (aluminum absorption gratings on Si and GaAs substrates). The polarization sensitive absorption characteristics of the suboptical wavelength lithographic grating were exploited in order to explore various acoustic generation and detection schemes.

  5. What are the ideal wavelengths for full color holography?

    NASA Astrophysics Data System (ADS)

    Bazargan, Kaveh

    2013-02-01

    One of the holy grails in display holography is the production of natural color holographic images. Various sets of wavelengths for recording have been suggested, some favoring three wavelengths, some four, and even more. I will argue that the choice of recording wavelengths is completely independent of the holographic process; it was in fact was solved once and for all by scientists working in general lighting in the 1970s. I will suggest an ideal set of wavelengths which will produce color rendition equal to better than conventional photographic processes.

  6. Smoke optical depths - Magnitude, variability, and wavelength dependence

    NASA Technical Reports Server (NTRS)

    Pueschel, R. F.; Russell, P. B.; Colburn, D. A.; Ackerman, T. P.; Allen, D. A.

    1988-01-01

    An airborne autotracking sun-photometer has been used to measure magnitudes, temporal/spatial variabilities, and the wavelength dependence of optical depths in the near-ultraviolet to near-infrared spectrum of smoke from two forest fires and one jet fuel fire and of background air. Jet fuel smoke optical depths were found to be generally less wavelength dependent than background aerosol optical depths. Forest fire smoke optical depths, however, showed a wide range of wavelength depedences, such as incidents of wavelength-independent extinction.

  7. THE OPTICAL SPECTRA OF SPITZER 24 mum GALAXIES IN THE COSMIC EVOLUTION SURVEY FIELD. II. FAINT INFRARED SOURCES IN THE zCOSMOS-BRIGHT 10k CATALOG

    SciTech Connect

    Caputi, K. I.; Lilly, S. J.; Maier, C.; Carollo, C. M.; Aussel, H.; Floc'h, E. Le; Frayer, D.; Contini, T.; Kneib, J.-P.; Le Fevre, O.; Mainieri, V.; Renzini, A.; Scodeggio, M.; Scoville, N.; Zamorani, G.; Bardelli, S.; Bolzonella, M.; Coppa, G.; Bongiorno, A.

    2009-12-20

    We have used the zCOSMOS-bright 10k sample to identify 3244 Spitzer/MIPS 24 mum-selected galaxies with 0.06 mJy < S{sub 24{sub m}}u{sub m} approx< 0.50 mJy and I{sub AB} < 22.5, over 1.5 deg{sup 2} of the COSMOS field, and studied different spectral properties, depending on redshift. At 0.2 < z < 0.3, we found that different reddening laws of common use in the literature explain the dust extinction properties of approx80% of our infrared (IR) sources, within the error bars. For up to 16% of objects, instead, the Halpha lambda6563/Hbeta lambda4861 ratios are too high for their IR/UV attenuations, which is probably a consequence of inhomogeneous dust distributions. In only a few of our galaxies at 0.2 < z < 0.3, the IR emission could be mainly produced by dust heated by old rather than young stars. Besides, the line ratios of approx22% of our galaxies suggest that they might be star-formation/nuclear-activity composite systems. At 0.5 < z < 0.7, we estimated galaxy metallicities for 301 galaxies: at least 12% of them are securely below the upper-branch mass-metallicity trend, which is consistent with the local relation. Finally, we performed a combined analysis of the H{sub d}elta equivalent width versus D{sub n} (4000) diagram for 1722 faint and bright 24 mum galaxies at 0.6 < z < 1.0, spanning two decades in mid-IR luminosity. We found that, while secondary bursts of star formation are necessary to explain the position of the most luminous IR galaxies in that diagram, quiescent, exponentially declining star formation histories can well reproduce the spectral properties of approx40% of the less luminous sources. Our results suggest a transition in the possible modes of star formation at total IR luminosities L{sub TIR} approx (3 +- 2) x 10{sup 11} L{sub sun}.

  8. Spitzer/MIPS 24 {mu}m OBSERVATIONS OF HD 209458b: THREE ECLIPSES, TWO AND A HALF TRANSITS, AND A PHASE CURVE CORRUPTED BY INSTRUMENTAL SENSITIVITY VARIATIONS

    SciTech Connect

    Crossfield, Ian J. M.; Knutson, Heather; Fortney, Jonathan; Showman, Adam P.; Cowan, Nicolas B.; Deming, Drake

    2012-06-20

    We report the results of an analysis of all Spitzer/MIPS 24 {mu}m observations of HD 209458b, one of the touchstone objects in the study of irradiated giant planet atmospheres. Altogether, we analyze two and a half transits, three eclipses, and a 58 hr near-continuous observation designed to detect the planet's thermal phase curve. The results of our analysis are: (1) a mean transit depth of 1.484% {+-} 0.033%, consistent with previous measurements and showing no evidence of variability in transit depth at the 3% level. (2) A mean eclipse depth of 0.338% {+-} 0.026%, somewhat higher than that previously reported for this system; this new value brings observations into better agreement with models. From this eclipse depth we estimate an average dayside brightness temperature of 1320 {+-} 80 K; the dayside flux shows no evidence of variability at the 12% level. (3) Eclipses in the system occur 32 {+-} 129 s earlier than would be expected from a circular orbit, which constrains the orbital quantity ecos {omega} to be 0.00004 {+-} 0.00033. This result is fully consistent with a circular orbit and sets an upper limit of 140 m s{sup -1} (3{sigma}) on any eccentricity-induced velocity offset during transit. The phase curve observations (including one of the transits) exhibit an anomalous trend similar to the detector ramp seen in previous Spitzer/IRAC observations; by modeling this ramp we recover the system parameters for this transit. The long-duration photometry which follows the ramp and transit exhibits a gradual {approx}0.2% decrease in flux over {approx}30 hr. This effect is similar to that seen in pre-launch calibration data taken with the 24 {mu}m array and is better fit by an instrumental model than a model invoking planetary emission. The large uncertainties associated with this poorly understood, likely instrumental effect prevent us from usefully constraining the planet's thermal phase curve. Our observations highlight the need for a thorough understanding of

  9. An Update on the Long Wavelength Array

    NASA Astrophysics Data System (ADS)

    Taylor, Gregory B.; Tremblay, S. E.; Pihlstrom, Y.; Craig, J.; Rickard, L.; Dowell, J.; Kassim, N.; Clarke, T.; Hicks, B.; Polisensky, E.; Ray, P.; Schmitt, H.; Woods, D.; Hartman, J.; Ellingson, S.; Wolfe, C.; Navarro, R.; Sigman, E.; Soriano, M.; Owen, F.

    2011-01-01

    The Long Wavelength Array (LWA), a SKA Pathfinder, will be a new multi-purpose radio telescope operating in the frequency range 10-88 MHz. Scientific programs include pulsars, supernova remnants, general transient searches, radio recombination lines, solar and Jupiter bursts, investigations into the "dark ages" using redshifted hydrogen, and ionospheric phenomena. Upon completion, LWA will consist of 53 phased array "stations” distributed across a region over 400 km in diameter. Each station consists of 256 pairs of dipole-type antennas whose signals are formed into beams, with outputs transported to a central location for high-resolution aperture synthesis imaging. The resulting image sensitivity is estimated to be a few mJy (5sigma, 8 MHz, 2 polarizations, 1 h, zenith) from 20-80 MHz; with angular resolution of a few arcseconds. A technical overview of the LWA project is available (Ellingson etal. 2009, Proc. IEEE, 97, 1421), and additional information is online at http://lwa.unm.edu. Partners in the LWA project include LANL, JPL, NRAO, NRL, UNM, NMT, and Virginia Tech. The first station of the LWA, called "LWA-1", is located near the center of the EVLA and is expected to achieve initial operational capability in early 2011. As of September 2010, all antennas have been installed as well as a subset of the "production” versions of receivers, digital electronics, data recorders, and monitoring and control system. The "transient buffer - wideband” (TBW) capability is operational with 20 dipoles, and provides the ability to capture simultaneous raw 196 MSPS A/D output over the entire 10-88 MHz tuning range in 61 ms bursts. Other operating modes are in the final stages of implementation. Some early results obtained with LWA-1 will be presented. Funding for the LWA has been provided by the Office of Naval Research.

  10. Ultra-short wavelength operation of a thulium fibre laser in the 1660-1750 nm wavelength band.

    PubMed

    Daniel, J M O; Simakov, N; Tokurakawa, M; Ibsen, M; Clarkson, W A

    2015-07-13

    Ultra-short wavelength operation of a thulium fibre laser is investigated. Through use of core pumping and high feedback efficiency wavelength selection, a continuously-tunable fibre laser source operating from 1660 nm to 1720 nm is demonstrated in a silica host. We discuss the range of applications within this important wavelength band such as polymer materials processing and medical applications targeting characteristic C-H bond resonance peaks. As a demonstration of the power scalability of thulium fibre lasers in this band, fixed wavelength operation at 1726 nm with output power up 12.6 W and with slope efficiency > 60% is also shown. PMID:26191883

  11. FIRST RESULTS FROM VERY LARGE TELESCOPE NACO APODIZING PHASE PLATE: 4 {mu}m IMAGES OF THE EXOPLANET {beta} PICTORIS b

    SciTech Connect

    Quanz, Sascha P.; Meyer, Michael R.; Kenworthy, Matthew A.; Girard, Julien H. V.; Kasper, Markus; Lagrange, Anne-Marie; Bonnefoy, Mickael; Chauvin, Gael; Apai, Daniel; Boccaletti, Anthony; Hinz, Philip M.; Lenzen, Rainer

    2010-10-10

    Direct imaging of exoplanets requires both high contrast and high spatial resolution. Here, we present the first scientific results obtained with the newly commissioned apodizing phase plate coronagraph (APP) on VLT/NACO. We detected the exoplanet {beta} Pictoris b in the narrowband filter centered at 4.05 {mu}m (NB4.05). The position angle (209.{sup 0}13 {+-} 2.{sup 0}12) and the projected separation to its host star (0.''354 {+-} 0.''012, i.e., 6.8 {+-} 0.2 AU at a distance of 19.3 pc) are in good agreement with the recently presented data from Lagrange et al. Comparing the observed NB4.05 magnitude of 11.20 {+-} 0.23 mag to theoretical atmospheric models, we find a best fit with a 7-10 M {sub Jupiter} object for an age of 12 Myr, again in agreement with previous estimates. Combining our results with published L' photometry, we can compare the planet's [L' - NB4.05] color to that of cool field dwarfs of higher surface gravity suggesting an effective temperature of {approx}1700 K. The best-fit theoretical model predicts an effective temperature of {approx}1470 K, but this difference is not significant given our photometric uncertainties. Our results demonstrate the potential of NACO/APP for future planet searches and provide independent confirmation as well as complementary data for {beta} Pic b.

  12. RE-EVALUATING WASP-12b: STRONG EMISSION AT 2.315 {mu}m, DEEPER OCCULTATIONS, AND AN ISOTHERMAL ATMOSPHERE

    SciTech Connect

    Crossfield, Ian J. M.; Barman, Travis; Hansen, Brad M. S.; Tanaka, Ichi; Kodama, Tadayuki

    2012-12-01

    We revisit the atmospheric properties of the extremely hot Jupiter WASP-12b in light of several new developments. First, we present new narrowband (2.315 {mu}m) secondary eclipse photometry, which exhibits a planet/star flux ratio of 0.45% {+-} 0.06%, corresponding to a brightness temperature of 3640 {+-} 230 K; second, recent Spitzer/Infrared Array Camera and Hubble Space Telescope/Wide Field Camera 3 observations; and third, a recently observed star only 1'' from WASP-12, which has diluted previous observations and which we further characterize here. We correct past WASP-12b eclipse measurements for the presence of this object, and we revisit the interpretation of WASP-12b's dilution-corrected emission spectrum. The resulting planetary emission spectrum is well approximated by a blackbody, and consequently our primary conclusion is that the planet's infrared photosphere is nearly isothermal. Thus, secondary eclipse spectroscopy is relatively ill suited to constrain WASP-12b's atmospheric abundances, and transmission spectroscopy may be necessary to achieve this goal.

  13. ADAPTIVE OPTICS OBSERVATIONS OF 3 {mu}m WATER ICE IN SILHOUETTE DISKS IN THE ORION NEBULA CLUSTER AND M43

    SciTech Connect

    Terada, Hiroshi; Pyo, Tae-Soo; Minowa, Yosuke; Hayano, Yutaka; Oya, Shin; Hattori, Masayuki; Takami, Hideki; Tokunaga, Alan T.; Watanabe, Makoto; Saito, Yoshihiko; Ito, Meguru; Iye, Masanori

    2012-12-01

    We present the near-infrared images and spectra of four silhouette disks in the Orion Nebula Cluster (M42) and M43 using the Subaru Adaptive Optics system. While d053-717 and d141-1952 show no water ice feature at 3.1 {mu}m, a moderately deep ({tau}{sub ice} {approx} 0.7) water ice absorption is detected toward d132-1832 and d216-0939. Taking into account the water ice so far detected in the silhouette disks, the critical inclination angle to produce a water ice absorption feature is confirmed to be 65 Degree-Sign -75 Degree-Sign . As for d216-0939, the crystallized water ice profile is exactly the same as in the previous observations taken 3.63 years ago. If the water ice material is located at 30 AU, then the observations suggest it is uniform at a scale of about 3.5 AU.

  14. The Effect of the More Active MuMs in Stirling Trial on Body Composition and Psychological Well-Being among Postnatal Women.

    PubMed

    Lee, Alyssa S; McInnes, Rhona J; Hughes, Adrienne R; Guthrie, Wendy; Jepson, Ruth

    2016-01-01

    Introduction. Physical activity is important for health and well-being; however, rates of postnatal physical activity can be low. This paper reports the secondary outcomes of a trial aimed at increasing physical activity among postnatal women. Methods. More Active MuMs in Stirling (MAMMiS) was a randomised controlled trial testing the effect of physical activity consultation and pram walking group intervention among inactive postnatal women. Data were collected on postnatal weight, body composition, general well-being, and fatigue. Participants were also interviewed regarding motivations and perceived benefits of participating in the trial. Results. There was no significant effect of the intervention on any weight/body composition outcome or on general well-being at three or six months of follow-up. There was a significant but inconsistent difference in fatigue between groups. Qualitative data highlighted a number of perceived benefits to weight, body composition, and particularly well-being (including improved fatigue) which were not borne out by objective data. Discussion. The MAMMiS study found no impact of the physical activity intervention on body composition and psychological well-being and indicates that further research is required to identify successful approaches to increase physical activity and improve health and well-being among postnatal women.

  15. The Effect of the More Active MuMs in Stirling Trial on Body Composition and Psychological Well-Being among Postnatal Women

    PubMed Central

    Jepson, Ruth

    2016-01-01

    Introduction. Physical activity is important for health and well-being; however, rates of postnatal physical activity can be low. This paper reports the secondary outcomes of a trial aimed at increasing physical activity among postnatal women. Methods. More Active MuMs in Stirling (MAMMiS) was a randomised controlled trial testing the effect of physical activity consultation and pram walking group intervention among inactive postnatal women. Data were collected on postnatal weight, body composition, general well-being, and fatigue. Participants were also interviewed regarding motivations and perceived benefits of participating in the trial. Results. There was no significant effect of the intervention on any weight/body composition outcome or on general well-being at three or six months of follow-up. There was a significant but inconsistent difference in fatigue between groups. Qualitative data highlighted a number of perceived benefits to weight, body composition, and particularly well-being (including improved fatigue) which were not borne out by objective data. Discussion. The MAMMiS study found no impact of the physical activity intervention on body composition and psychological well-being and indicates that further research is required to identify successful approaches to increase physical activity and improve health and well-being among postnatal women. PMID:27610245

  16. The Effect of the More Active MuMs in Stirling Trial on Body Composition and Psychological Well-Being among Postnatal Women.

    PubMed

    Lee, Alyssa S; McInnes, Rhona J; Hughes, Adrienne R; Guthrie, Wendy; Jepson, Ruth

    2016-01-01

    Introduction. Physical activity is important for health and well-being; however, rates of postnatal physical activity can be low. This paper reports the secondary outcomes of a trial aimed at increasing physical activity among postnatal women. Methods. More Active MuMs in Stirling (MAMMiS) was a randomised controlled trial testing the effect of physical activity consultation and pram walking group intervention among inactive postnatal women. Data were collected on postnatal weight, body composition, general well-being, and fatigue. Participants were also interviewed regarding motivations and perceived benefits of participating in the trial. Results. There was no significant effect of the intervention on any weight/body composition outcome or on general well-being at three or six months of follow-up. There was a significant but inconsistent difference in fatigue between groups. Qualitative data highlighted a number of perceived benefits to weight, body composition, and particularly well-being (including improved fatigue) which were not borne out by objective data. Discussion. The MAMMiS study found no impact of the physical activity intervention on body composition and psychological well-being and indicates that further research is required to identify successful approaches to increase physical activity and improve health and well-being among postnatal women. PMID:27610245

  17. The Effect of the More Active MuMs in Stirling Trial on Body Composition and Psychological Well-Being among Postnatal Women

    PubMed Central

    Jepson, Ruth

    2016-01-01

    Introduction. Physical activity is important for health and well-being; however, rates of postnatal physical activity can be low. This paper reports the secondary outcomes of a trial aimed at increasing physical activity among postnatal women. Methods. More Active MuMs in Stirling (MAMMiS) was a randomised controlled trial testing the effect of physical activity consultation and pram walking group intervention among inactive postnatal women. Data were collected on postnatal weight, body composition, general well-being, and fatigue. Participants were also interviewed regarding motivations and perceived benefits of participating in the trial. Results. There was no significant effect of the intervention on any weight/body composition outcome or on general well-being at three or six months of follow-up. There was a significant but inconsistent difference in fatigue between groups. Qualitative data highlighted a number of perceived benefits to weight, body composition, and particularly well-being (including improved fatigue) which were not borne out by objective data. Discussion. The MAMMiS study found no impact of the physical activity intervention on body composition and psychological well-being and indicates that further research is required to identify successful approaches to increase physical activity and improve health and well-being among postnatal women.

  18. Two-chord interferometry using 3.39 {mu}m He-Ne laser on a flux-coil-generated FRC

    SciTech Connect

    Gota, H.; Deng, B. H.; Gupta, D.; Kiyashko, V.; Knapp, K.; Mendoza, R.; Morehouse, M.; Bolte, N.; Roche, T.; Wessel, F.

    2010-10-15

    A two-chord {lambda}{sub IR}{approx}3.39 {mu}m He-Ne laser interferometer system was developed for a flux-coil-generated field-reversed configuration to estimate the electron density and the total temperature of the field-reversed configuration (FRC) plasma. This two-chord heterodyne interferometer system consists of a single {approx}2 mW infrared He-Ne laser, a visible ({lambda}{sub vis}{approx}632.8 nm) He-Ne laser for the alignment, a 40 MHz acousto-optic modulator, photodetectors, and quadrature phase detectors. Initial measurement was performed and the measured average electron densities were 2-10x10{sup 19} m{sup -3} at two different radial positions in the midplane. A time shift in density was observed as the FRC expands radially. The time evolution of the line-averaged density agrees with the density estimated from the in situ internal magnetic probes, based on a rigid-rotor profile model.

  19. Modelling, Design, Growth and Characterization of Strain Balanced Quantum Cascade Lasers (3-11mum), grown by Gas Source Molecular Beam Epitaxy

    NASA Astrophysics Data System (ADS)

    Bandyopadhyay, Neelanjan

    Quantum Cascade Laser (QCL) is a compact room temperature (RT) source of mid-infrared radiation, which can be used for spectroscopic detection of trace amount of chemicals. The mid-infrared spectral range between (3-11 microm), has a dense array of absorption lines of numerous molecules, due to the presence of fundamental vibrational modes. The goal of this thesis can be subdivided into two parts. Firstly, short wavelength QCLs, emitting below 4microm, perform poorly at RT, due to inter-valley Gamma --- L carrier scattering, carrier escape to the continuum, heat removal from the core region at high power density corresponding to short wavelength operation, and large interface scattering due to highly strained materials. Secondly, it is desirable to have a single QCL based source emitting between 6-10microm, which be used to detect multiple molecules having their peak absorptions far apart, inside this spectral range. However, gain bandwidth of a single core QCL is relatively small, so laser emission cannot be tuned over a wide spectral range. This thesis describes the working principle of a QCL based on superlattice transport, rate equations, scattering mechanism, and waveguide design. The choice of the material system for this work and the fundamentals of band structure engineering has been derived. Gas source molecular beam epitaxy - growth optimization and characterization is one of the most important features of this work, especially for short wavelength QCLs, and has been explained in depth. Different strategies for design of active region design of short wavelength QCL and heterogeneous broadband QCL has been explored. The major milestones, of this research was the world's first watt level continuous wave (CW), RT demonstration at 3.76 microm, which was followed by another milestone of the first CW, RT demonstration at 3.39microm and 3.55microm, and finally the elusive result of QCL emitting at CW, RT at a wavelength as short as lambda ~3microm, a record. In

  20. UV-TO-FIR ANALYSIS OF SPITZER/IRAC SOURCES IN THE EXTENDED GROTH STRIP. I. MULTI-WAVELENGTH PHOTOMETRY AND SPECTRAL ENERGY DISTRIBUTIONS

    SciTech Connect

    Barro, Guillermo; Perez-Gonzalez, P. G.; Gallego, J.; Villar, V.; Zamorano, J.; Ashby, M. L. N.; Kajisawa, M.; Yamada, T.; Miyazaki, S.

    2011-03-15

    We present an IRAC 3.6+4.5 {mu}m selected catalog in the Extended Groth Strip (EGS) containing photometry from the ultraviolet to the far-infrared and stellar parameters derived from the analysis of the multi-wavelength data. In this paper, we describe the method used to build coherent spectral energy distributions (SEDs) for all the sources. In a forthcoming companion paper, we analyze those SEDs to obtain robust estimations of stellar parameters such as photometric redshifts, stellar masses, and star formation rates. The catalog comprises 76,936 sources with [3.6] {<=} 23.75 mag (85% completeness level of the IRAC survey in the EGS) over 0.48 deg{sup 2}. For approximately 16% of this sample, we are able to deconvolve the IRAC data to obtain robust fluxes for the multiple counterparts found in ground-based optical images. Typically, the SEDs of the IRAC sources in our catalog count with more than 15 photometric data points, spanning from the ultraviolet wavelengths probed by GALEX to the far-infrared observed by Spitzer, and going through ground- and space-based optical and near-infrared data taken with 2-8 m class telescopes. Approximately 95% and 90% of all IRAC sources are detected in the deepest optical and near-infrared bands. These fractions are reduced to 85% and 70% for S/N > 5 detections in each band. Only 10% of the sources in the catalog have optical spectroscopy and redshift estimations. Almost 20% and 2% of the sources are detected by MIPS at 24 and 70 {mu}m, respectively. We also cross-correlate our catalog with public X-ray and radio catalogs. Finally, we present the Rainbow Navigator public Web interface utility, designed to browse all the data products resulting from this work, including images, spectra, photometry, and stellar parameters.

  1. Micro-mechanical wavelength-selectable switches for photonic networks

    NASA Astrophysics Data System (ADS)

    Mizukami, Masato; Katagiri, Yoshitada

    2005-12-01

    Reconfigurable wideband photonic networks based on dense wavelength division multiplexing (WDM) are promising for versatile ubiquitous services. In such networks, wavelength-selectable optical switches will be needed for WDM-based routing, which is a primary function of the networks. A critical requirement is a wavelength selection time of 20 ms or less; otherwise, data packets will be lost. Various filters, including acousto-optic filters or Fabry-Perot etalon filters, are candidates for such switches, but all are inadequate because of high driving power or low accuracy in selecting wavelengths. We propose and demonstrate a wavelength-selectable switch that consists of micromechanically movable in/out filters. A series of thirty-two in/out elements with highly wavelength-managed dielectric filter units, which have flat-top spectral responses according to ITU-T grids, are densely packaged into a small space of 45 x24 x11 mm using miniaturized voice-coil motors (VCMs). By accurately arranging the filter elements along a collimating optical beam between fibers, we achieve small total insertion losses of less than 2.5 dB for all elements. By optimizing the VCM torque, we also achieve a wavelength-selection time of 10 ms (The minimum is 5 ms). We also achieve good wavelength reproducibility with an error of less than 0.1 nm, which was confirmed by a repetition test. These results show that the proposed switches are suitable for practical use.

  2. Fast fiber-optic multi-wavelength pyrometer

    NASA Astrophysics Data System (ADS)

    Fu, Tairan; Tan, Peng; Pang, Chuanhe; Zhao, Huan; Shen, Yi

    2011-06-01

    A fast fiber-optic multi-wavelength pyrometer was developed for the ultraviolet-visible-near infrared spectra from 200 nm to 1700 nm using a CCD detector and an InGaAs detector. The pyrometer system conveniently and quickly provides the sufficient choices of multiple measurement wavelengths using optical diffraction, which avoids the use of narrow-band filters. Flexible optical fibers are used to transmit the radiation so the pyrometer can be used for temperature measurements in harsh environments. The setup and calibrations (wavelength calibration, nonlinearity calibration, and radiation response calibration) of this pyrometer system were described. Development of the multi-wavelength pyrometer involved optimization of the bandwidth and temperature discrimination of the multiple spectra data. The analysis results showed that the wavelength intervals, ΔλCCD = 30 nm and ΔλInGaAs = 50 nm, are the suitable choices as a tradeoff between the simple emissivity model assumption and the multiple signal discrimination. The temperature discrimination was also quantificationally evaluated for various wavelengths and temperatures. The measurement performance of the fiber-optic multi-wavelength pyrometer was partially verified through measurements with a high-temperature blackbody and actual hot metals. This multi-wavelength pyrometer can be used for remote high-temperature measurements.

  3. Multichannel SNSPD system with high detection efficiency at telecommunication wavelength.

    PubMed

    Miki, Shigehito; Yamashita, Taro; Fujiwara, Mikio; Sasaki, Masahide; Wang, Zhen

    2010-07-01

    We developed a four-channel superconducting nanowire single-photon detector system based on a Gifford-McMahon cryocooler. All channels showed a system detection efficiency (DE) (at a 100 Hz dark-count rate) higher than 16% at 1550 nm wavelength, and the best channel showed a system DE of 21% and 30% at 1550 and 1310 nm wavelength, respectively.

  4. 47 CFR 2.101 - Frequency and wavelength bands.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... Frequency and wavelength bands. (a) The radio spectrum shall be subdivided into nine frequency bands, which... 47 Telecommunication 1 2011-10-01 2011-10-01 false Frequency and wavelength bands. 2.101 Section 2... GHz: For frequencies above 10 500 MHz. Band number Symbols Frequency range (lower limit...

  5. 47 CFR 2.101 - Frequency and wavelength bands.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Frequency and wavelength bands. (a) The radio spectrum shall be subdivided into nine frequency bands, which... 47 Telecommunication 1 2010-10-01 2010-10-01 false Frequency and wavelength bands. 2.101 Section 2... frequencies, the lists of frequencies and related matters, reasonable departures may be made. Band...

  6. 47 CFR 2.101 - Frequency and wavelength bands.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... Frequency and wavelength bands. (a) The radio spectrum shall be subdivided into nine frequency bands, which... 47 Telecommunication 1 2013-10-01 2013-10-01 false Frequency and wavelength bands. 2.101 Section 2... limit inclusive) Corresponding metric subdivision Metricabbreviations for the bands 4 VLF 3 to 30...

  7. 47 CFR 2.101 - Frequency and wavelength bands.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... Frequency and wavelength bands. (a) The radio spectrum shall be subdivided into nine frequency bands, which... 47 Telecommunication 1 2012-10-01 2012-10-01 false Frequency and wavelength bands. 2.101 Section 2... limit inclusive) Corresponding metric subdivision Metricabbreviations for the bands 4 VLF 3 to 30...

  8. 47 CFR 2.101 - Frequency and wavelength bands.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... Frequency and wavelength bands. (a) The radio spectrum shall be subdivided into nine frequency bands, which... 47 Telecommunication 1 2014-10-01 2014-10-01 false Frequency and wavelength bands. 2.101 Section 2... limit inclusive) Corresponding metric subdivision Metricabbreviations for the bands 4 VLF 3 to 30...

  9. Systematic wavelength selection for improved multivariate spectral analysis

    DOEpatents

    Thomas, Edward V.; Robinson, Mark R.; Haaland, David M.

    1995-01-01

    Methods and apparatus for determining in a biological material one or more unknown values of at least one known characteristic (e.g. the concentration of an analyte such as glucose in blood or the concentration of one or more blood gas parameters) with a model based on a set of samples with known values of the known characteristics and a multivariate algorithm using several wavelength subsets. The method includes selecting multiple wavelength subsets, from the electromagnetic spectral region appropriate for determining the known characteristic, for use by an algorithm wherein the selection of wavelength subsets improves the model's fitness of the determination for the unknown values of the known characteristic. The selection process utilizes multivariate search methods that select both predictive and synergistic wavelengths within the range of wavelengths utilized. The fitness of the wavelength subsets is determined by the fitness function F=.function.(cost, performance). The method includes the steps of: (1) using one or more applications of a genetic algorithm to produce one or more count spectra, with multiple count spectra then combined to produce a combined count spectrum; (2) smoothing the count spectrum; (3) selecting a threshold count from a count spectrum to select these wavelength subsets which optimize the fitness function; and (4) eliminating a portion of the selected wavelength subsets. The determination of the unknown values can be made: (1) noninvasively and in vivo; (2) invasively and in vivo; or (3) in vitro.

  10. Correction of wavelength errors in a digitally recording spectrophotometer.

    PubMed

    Robertson, A R; Budde, W; McNeely, F T

    1973-12-01

    A simple circuit is described that enables known wavelength errors of a digitally recording spectrophotometer to be corrected. The circuit delays the signal that triggers the recording system. The length of the delay is varied as a function of wavelength to correct for the errors. Significant improvement can be obtained in the measurement of CIE tristimulus values.

  11. Planarian Phototactic Assay Reveals Differential Behavioral Responses Based on Wavelength

    PubMed Central

    Paskin, Taylor R.; Jellies, John; Bacher, Jessica; Beane, Wendy S.

    2014-01-01

    Planarians are free-living aquatic flatworms that possess a well-documented photophobic response to light. With a true central nervous system and simple cerebral eyes (ocelli), planarians are an emerging model for regenerative eye research. However, comparatively little is known about the physiology of their photoreception or how their behavior is affected by various wavelengths. Most phototactic studies have examined planarian behavior using white light. Here, we describe a novel planarian behavioral assay to test responses to small ranges of visible wavelengths (red, blue, green), as well as ultraviolet (UV) and infrared (IR) which have not previously been examined. Our data show that planarians display behavioral responses across a range of wavelengths. These responses occur in a hierarchy, with the shortest wavelengths (UV) causing the most intense photophobic responses while longer wavelengths produce no effect (red) or an apparent attraction (IR). In addition, our data reveals that planarian photophobia is comprised of both a general photophobic response (that drives planarians to escape the light source regardless of wavelength) and wavelength-specific responses that encompass specific behavioral reactions to individual wavelengths. Our results serve to improve the understanding of planarian phototaxis and suggest that behavioral studies performed with white light mask a complex behavioral interaction with the environment. PMID:25493551

  12. Selection of Wavelengths for Optimum Precision in Simultaneous Spectrophotometric Determinations.

    ERIC Educational Resources Information Center

    DiTusa, Michael R.; Schilt, Alfred A.

    1985-01-01

    Although many textbooks include a description of simultaneous determinations employing absorption spectrophotometry and treat the mathematics necessary for analytical quantitations, treatment of analytical wavelength selection has been mostly qualitative. Therefore, a general method for selecting wavelengths for optimum precision in simultaneous…

  13. Fast fiber-optic multi-wavelength pyrometer.

    PubMed

    Fu, Tairan; Tan, Peng; Pang, Chuanhe; Zhao, Huan; Shen, Yi

    2011-06-01

    A fast fiber-optic multi-wavelength pyrometer was developed for the ultraviolet-visible-near infrared spectra from 200 nm to 1700 nm using a CCD detector and an InGaAs detector. The pyrometer system conveniently and quickly provides the sufficient choices of multiple measurement wavelengths using optical diffraction, which avoids the use of narrow-band filters. Flexible optical fibers are used to transmit the radiation so the pyrometer can be used for temperature measurements in harsh environments. The setup and calibrations (wavelength calibration, nonlinearity calibration, and radiation response calibration) of this pyrometer system were described. Development of the multi-wavelength pyrometer involved optimization of the bandwidth and temperature discrimination of the multiple spectra data. The analysis results showed that the wavelength intervals, Δλ(CCD) = 30 nm and Δλ(InGaAs) = 50 nm, are the suitable choices as a tradeoff between the simple emissivity model assumption and the multiple signal discrimination. The temperature discrimination was also quantificationally evaluated for various wavelengths and temperatures. The measurement performance of the fiber-optic multi-wavelength pyrometer was partially verified through measurements with a high-temperature blackbody and actual hot metals. This multi-wavelength pyrometer can be used for remote high-temperature measurements. PMID:21721719

  14. Polarization-independent optical wavelength filter for channel dropping applications

    DOEpatents

    Deri, R.J.; Patterson, F.

    1996-05-07

    The polarization dependence of optical wavelength filters is eliminated by using waveguide directional couplers. Material birefringence is used to compensate for the waveguide (electromagnetic) birefringence which is the original cause of the polarization dependence. Material birefringence is introduced in a controllable fashion by replacing bulk waveguide layers by finely layered composites, such as multiple quantum wells using III-V semiconductor materials. The filter has use in wavelength-division multiplexed fiber optic communication systems. This filter has broad application for wavelength-tunable receivers in fiber optic communication links, which may be used for telecommunications, optical computer interconnect links, or fiber optic sensor systems. Since multiple-wavelength systems are increasingly being used for all of these applications, the filter is useable whenever a rapidly tunable, wavelength-filtering receiver is required. 14 figs.

  15. Lethal effects of short-wavelength visible light on insects

    NASA Astrophysics Data System (ADS)

    Hori, Masatoshi; Shibuya, Kazuki; Sato, Mitsunari; Saito, Yoshino

    2014-12-01

    We investigated the lethal effects of visible light on insects by using light-emitting diodes (LEDs). The toxic effects of ultraviolet (UV) light, particularly shortwave (i.e., UVB and UVC) light, on organisms are well known. However, the effects of irradiation with visible light remain unclear, although shorter wavelengths are known to be more lethal. Irradiation with visible light is not thought to cause mortality in complex animals including insects. Here, however, we found that irradiation with short-wavelength visible (blue) light killed eggs, larvae, pupae, and adults of Drosophila melanogaster. Blue light was also lethal to mosquitoes and flour beetles, but the effective wavelength at which mortality occurred differed among the insect species. Our findings suggest that highly toxic wavelengths of visible light are species-specific in insects, and that shorter wavelengths are not always more toxic. For some animals, such as insects, blue light is more harmful than UV light.

  16. Luminescence quantum yields of gold nanoparticles varying with excitation wavelengths.

    PubMed

    Cheng, Yuqing; Lu, Guowei; He, Yingbo; Shen, Hongming; Zhao, Jingyi; Xia, Keyu; Gong, Qihuang

    2016-01-28

    Luminescence quantum yields (QYs) of gold nanoparticles including nanorods, nanobipyramids and nanospheres are measured elaborately at a single nanoparticle level with different excitation wavelengths. It is found that the QYs of the nanostructures are essentially dependent on the excitation wavelength. The QY is higher when the excitation wavelength is blue-detuned and close to the nanoparticles' surface plasmon resonance peak. A phenomenological model based on the plasmonic resonator concept is proposed to understand the experimental findings. The excitation wavelength dependent QY is attributed to the wavelength dependent coupling efficiency between the free electron oscillation and the intrinsic plasmon resonant radiative mode. These studies should contribute to the understanding of one-photon luminescence from metallic nanostructures and plasmonic surface enhanced spectroscopy. PMID:26731570

  17. Luminescence quantum yields of gold nanoparticles varying with excitation wavelengths

    NASA Astrophysics Data System (ADS)

    Cheng, Yuqing; Lu, Guowei; He, Yingbo; Shen, Hongming; Zhao, Jingyi; Xia, Keyu; Gong, Qihuang

    2016-01-01

    Luminescence quantum yields (QYs) of gold nanoparticles including nanorods, nanobipyramids and nanospheres are measured elaborately at a single nanoparticle level with different excitation wavelengths. It is found that the QYs of the nanostructures are essentially dependent on the excitation wavelength. The QY is higher when the excitation wavelength is blue-detuned and close to the nanoparticles' surface plasmon resonance peak. A phenomenological model based on the plasmonic resonator concept is proposed to understand the experimental findings. The excitation wavelength dependent QY is attributed to the wavelength dependent coupling efficiency between the free electron oscillation and the intrinsic plasmon resonant radiative mode. These studies should contribute to the understanding of one-photon luminescence from metallic nanostructures and plasmonic surface enhanced spectroscopy.

  18. Lethal effects of short-wavelength visible light on insects.

    PubMed

    Hori, Masatoshi; Shibuya, Kazuki; Sato, Mitsunari; Saito, Yoshino

    2014-12-09

    We investigated the lethal effects of visible light on insects by using light-emitting diodes (LEDs). The toxic effects of ultraviolet (UV) light, particularly shortwave (i.e., UVB and UVC) light, on organisms are well known. However, the effects of irradiation with visible light remain unclear, although shorter wavelengths are known to be more lethal. Irradiation with visible light is not thought to cause mortality in complex animals including insects. Here, however, we found that irradiation with short-wavelength visible (blue) light killed eggs, larvae, pupae, and adults of Drosophila melanogaster. Blue light was also lethal to mosquitoes and flour beetles, but the effective wavelength at which mortality occurred differed among the insect species. Our findings suggest that highly toxic wavelengths of visible light are species-specific in insects, and that shorter wavelengths are not always more toxic. For some animals, such as insects, blue light is more harmful than UV light.

  19. Polarization-independent optical wavelength filter for channel dropping applications

    DOEpatents

    Deri, Robert J.; Patterson, Frank

    1996-01-01

    The polarization dependence of optical wavelength filters is eliminated by using waveguide directional couplers. Material birefringence is used to compensate for the waveguide (electromagnetic) birefringence which is the original cause of the polarization dependence. Material birefringence is introduced in a controllable fashion by replacing bulk waveguide layers by finely layered composites, such as multiple quantum wells using III-V semiconductor materials. The filter has use in wavelength-division-multiplexed fiber optic communication systems. This filter has broad application for wavelength-tunable receivers in fiber optic communication links, which may be used for telecommunications, optical computer interconnect links, or fiber optic sensor systems. Since multiple-wavelength systems are increasingly being used for all of these applications, the filter is useable whenever a rapidly tunable, wavelength-filtering receiver is required.

  20. Evaluation of wavelength groups for discrimination of agricultural cover types

    NASA Technical Reports Server (NTRS)

    Kumar, R.

    1978-01-01

    Multispectral scanner data in twelve spectral channels, in the wavelength range 0.46 to 11.7 microns, acquired in July, 1971, for three flightlines, were analyzed by applying automatic pattern recognition techniques. These twelve spectral channels were divided into four wavelength groups (W1, W2, W3 and W4), each consisting of three wavelength groups - with respect to their estimated probability of correct classification (Pc) - in discriminating agricultural cover types. The same analysis was also done for the data acquired in August, to investigate the effect of time on these results. The effect of deletion of each of the wavelength groups on Pc, in the subsets of one to nine channels, is given. Values of Pc for all possible combinations of wavelength groups, in the subsets of one to eleven channels, are also given.

  1. Synthetic-wavelength self-mixing interferometry for displacement measurement

    NASA Astrophysics Data System (ADS)

    Chen, Junbao; Zhu, Hongbin; Xia, Wei; Guo, Dongmei; Hao, Hui; Wang, Ming

    2016-06-01

    A simple synthetic-wavelength self-mixing interferometer is proposed for precision displacement measurement. Choosing the frequency difference of the orthogonally polarized dual frequency He-Ne laser appropriately, we introduce synthetic wavelength theory into self-mixing interference principle and demonstrate a feasible optical configuration by simply adjusting the optical design of self-mixing interferometer. The phase difference between the two orthogonally polarized feedback fringes is observed, and the tiny displacement of the object can be measured through the phase change of the synthetic signal. Since the virtual synthetic wavelength is 106 times larger than the operating wavelength, sub-nanometer displacement of the object can be obtained in millimeter criterion measurement without modulation, demodulation and complicated electrical circuits. Experimental results verifies the synthetic wavelength self-mixing interferometer's ability of measuring nanoscale displacement, which provides a potential approach for contactless precision displacement measurement in a number of scientific and industrial applications.

  2. Passive Q-switching of a 1.66-{mu}m Er{sup 3+}:YAlO{sub 3} laser by means of a Cr{sup 2+}:ZnSe crystal

    SciTech Connect

    Galagan, B I; Denker, B I; Sverchkov, S E; Kuleshov, N V; Kisel', V E; Levchenko, V I

    2007-04-30

    The passive Q-switching of 1.66-{mu}m Er{sup 3+}:YAlO{sub 3} lasers with the help of some saturable absorbers is studied. Giant 200-ns pulses are generated by using a Cr{sup 2+}:ZnSe crystal as a saturable absorber. (control of laser radiation parameters)

  3. Relaxation oscillations of the intensity of the radiation from a 2-{mu}m thulium (Cr{sup 3+}, Tm{sup 3+} : YSGG) crystal laser operating under cw and pulsed conditions

    SciTech Connect

    Alpat'ev, A N; Smirnov, Valerii A; Shcherbakov, Ivan A

    1998-01-31

    Analytic expressions are derived for and quantitative estimates are obtained of the frequency and damping (decay) decrement of relaxation oscillations of the intensity of radiation from a 2-{mu}m thulium laser with a Cr{sup 3+}, Tm{sup 3+} : YSGG crystal operating under cw and pulsed conditions. (lasers)

  4. Two-fermion-four-boson description of {sup 198}Hg within the U{sub {nu}}(6/12) x U{sub {pi}}(6/4) extended nuclear structure supersymmetry

    SciTech Connect

    Bernards, C.; Heinze, S.; Jolie, J.; Fransen, C.; Linnemann, A.; Radeck, D.

    2009-05-15

    Using the U{sub {nu}}(6/12) x U{sub {pi}}(6/4) extended supersymmetry, we constructed the energy spectrum and electromagnetic transition properties of the supermultiplet member {sup 198}Hg with two proton fermions coupled to a neutron boson core. Consistency between the supersymmetric interacting boson fermion fermion approximation (IBFFA) description and the F-spin symmetric interacting boson approximation (IBA-2) description is shown for this two-fermion-N-boson multiplet member. The data of a {gamma}{gamma} angular correlation experiment using the HORUS cube {gamma}-ray spectrometer--determining new multipole mixing ratios, level spins, {gamma} transitions, and energy states--shows quite a good agreement, also for the low-energy part of the spectrum, when comparing theoretical predictions and experimental data. This is contrary to the usual assumption that a two-fermion-N-boson constellation should describe just the excited two-quasiparticle states.

  5. A MULTIWAVELENGTH STUDY OF A SAMPLE OF 70 {mu}m SELECTED GALAXIES IN THE COSMOS FIELD. II. THE ROLE OF MERGERS IN GALAXY EVOLUTION

    SciTech Connect

    Kartaltepe, Jeyhan S.; Sanders, D. B.; Le Floc'h, E.; Frayer, D. T.; Aussel, H.; Arnouts, S.; Ilbert, O.; Cassata, P.; Le Fevre, O.; Salvato, M.; Scoville, N. Z.; Capak, P.; Surace, J.; Yan, L.; Caputi, K.; Carollo, C. M.; Lilly, S.; Civano, F.; Hasinger, G.; Koekemoer, A. M.

    2010-09-20

    We analyze the morphological properties of a large sample of 1503 70 {mu}m selected galaxies in the COSMOS field spanning the redshift range 0.01 < z < 3.5 with a median redshift of 0.5 and an infrared luminosity range of 10{sup 8} < L{sub IR}(8 - 1000 {mu}m)< 10{sup 14} L{sub sun} with a median luminosity of 10{sup 11.4} L{sub sun}. In general, these galaxies are massive, with a stellar mass range of 10{sup 10}-10{sup 12} M{sub sun}, and luminous, with -25 < M{sub K} < -20. We find a strong correlation between the fraction of major mergers and L{sub IR}, with the fraction at the highest luminosity (L{sub IR} > 10{sup 12} L{sub sun}) being up to {approx}50%. We also find that the fraction of spirals drops dramatically with L{sub IR}. Minor mergers likely play a role in boosting the infrared luminosity for sources with low luminosities (L{sub IR} < 10{sup 11.5} L{sub sun}). The precise fraction of mergers in any given L{sub IR} bin varies by redshift due to sources at z > 1 being difficult to classify and subject to the effects of bandpass shifting; therefore, these numbers can only be considered lower limits. At z < 1, where the morphological classifications are most robust, major mergers clearly dominate the ULIRG population ({approx}50%-80%) and are important for the LIRG population ({approx}25%-40%). At z > 1, the fraction of major mergers is lower, but is at least 30%-40% for ULIRGs. In a comparison of our visual classifications with several automated classification techniques we find general agreement; however, the fraction of identified mergers is underestimated due to automated classification methods being sensitive to only certain timescales of a major merger. Although the general morphological trends agree with what has been observed for local (U)LIRGs, the fraction of major mergers is slightly lower than seen locally. This is in part due to the difficulty of identifying merger signatures at high redshift. The distribution of the U - V color of the

  6. Wavelength-Agile External-Cavity Diode Laser for DWDM

    NASA Technical Reports Server (NTRS)

    Pilgrim, Jeffrey S.; Bomse, David S.

    2006-01-01

    A prototype external-cavity diode laser (ECDL) has been developed for communication systems utilizing dense wavelength- division multiplexing (DWDM). This ECDL is an updated version of the ECDL reported in Wavelength-Agile External- Cavity Diode Laser (LEW-17090), NASA Tech Briefs, Vol. 25, No. 11 (November 2001), page 14a. To recapitulate: The wavelength-agile ECDL combines the stability of an external-cavity laser with the wavelength agility of a diode laser. Wavelength is modulated by modulating the injection current of the diode-laser gain element. The external cavity is a Littman-Metcalf resonator, in which the zeroth-order output from a diffraction grating is used as the laser output and the first-order-diffracted light is retro-reflected by a cavity feedback mirror, which establishes one end of the resonator. The other end of the resonator is the output surface of a Fabry-Perot resonator that constitutes the diode-laser gain element. Wavelength is selected by choosing the angle of the diffracted return beam, as determined by position of the feedback mirror. The present wavelength-agile ECDL is distinguished by design details that enable coverage of all 60 channels, separated by 100-GHz frequency intervals, that are specified in DWDM standards.

  7. Tweaks to Turing Patterns, Wavelength Transitions in CDIMA

    NASA Astrophysics Data System (ADS)

    Gaskins, Delora; Pruc, Emily; Dolnik, Milos; Epstein, Irving

    2015-03-01

    Alan Turing predicted that stationary patterns could arise from a uniform steady state in a system through the processes of reaction and diffusion. Beyond the Turing instability, there exist spatially periodic states with different wavelengths. Pattern transitions, including those transitions to patterns of differing wavelengths are of interest in reaction-diffusion systems including ecological systems with patterned biomass prone to desertification. We study pattern transitions in the chlorine dioxide-iodine-malonic acid (CDIMA) system which is the prototypical system for the study of Turing patterns in chemical systems. Additions of selected halides (bromides and chlorides) to the system in its patterned state have led to the observation of up to a five fold increase in wavelength. With the concentration of these halides as bifurcation parameter we observe that these large wavelength patterns are bistable with the uniform steady state. We explore the pattern wavelength selection of this system. Wavelength halving and super lattice structure formation result from transitions between patterns of different wavelengths.

  8. Wavelength discrimination in the hummingbird hawkmoth Macroglossum stellatarum.

    PubMed

    Telles, Francismeire J; Kelber, Almut; Rodríguez-Gironés, Miguel A

    2016-02-01

    Despite the strong relationship between insect vision and the spectral properties of flowers, the visual system has been studied in detail in only a few insect pollinator species. For instance, wavelength discrimination thresholds have been determined in two species only: the honeybee (Apis mellifera) and the butterfly Papilio xuthus. Here, we present the wavelength discrimination thresholds (Δλ) for the hawkmoth Macroglossum stellatarum. We compared the data with those found for the honeybee, the butterfly P. xuthus and the predictions of a colour discrimination model. After training moths to feed from a rewarded disc illuminated with a monochromatic light, we tested them in a dual-choice situation, in which they had to choose between light of the training wavelength and a novel unrewarded wavelength. To characterise the Δλ function, we decreased the difference between wavelengths in subsequent tests. We also varied the light intensity to test its effect on the discrimination capacity. In agreement with the predictions of the model, we found two expected minima of discrimination where photoreceptor sensitivities overlap, as well as a third, minor, unpredicted minimum around the peak of the blue photoreceptor. Macroglossum stellatarum is capable of discriminating between lights with a wavelength difference of 1-2 nm. These discrimination minima are similar to those found for the tetrachromatic P. xuthus, and are better than those of the honeybee. The moth is also capable of using achromatic information to discriminate between lights of long wavelengths. PMID:26747900

  9. HIGH-CONTRAST 3.8 {mu}m IMAGING OF THE BROWN DWARF/PLANET-MASS COMPANION TO GJ 758

    SciTech Connect

    Currie, Thayne; Bailey, Vanessa; Rodigas, Timothy; Hinz, Phil; Fabrycky, Daniel; Murray-Clay, Ruth

    2010-10-01

    We present L'-band (3.8 {mu}m) MMT/Clio high-contrast imaging data for the nearby star GJ 758, which was recently reported by Thalmann et al. to have one -- possibly two -- faint comoving companions (GJ 758B and 'C', respectively). GJ 758B is detected in two distinct data sets. Additionally, we report a possible detection of the object identified by Thalmann et al. as 'GJ 758C' in our more sensitive data set, though it is likely a residual speckle. However, if it is the same object as that reported by Thalmann et al. it cannot be a companion in a bound orbit. GJ 758B has an H - L' color redder than nearly all known L-T8 dwarfs. Based on comparisons with the COND evolutionary models, GJ 758B has T {sub e} {approx} 560 K{sup +150K}{sub -90 K}{sup +150 K) and a mass ranging from {approx}10-20 M{sub J} if it is {approx}1 Gyr old to {approx} 25-40 M{sub J} if it is 8.7 Gyr old. GJ 758B is likely in a highly eccentric orbit, e {approx} 0.73{sup +0.12}{sub -0.21}, with a semimajor axis of {approx}44 AU{sup +32 AU){sub -14 AU}. Though GJ 758B is sometimes discussed within the context of exoplanet direct imaging, its mass is likely greater than the deuterium-burning limit and its formation may resemble that of binary stars rather than that of Jovian-mass planets.

  10. The Smoking MUMS (Maternal Use of Medications and Safety) Study: protocol for a population-based cohort study using linked administrative data

    PubMed Central

    Havard, Alys; Jorm, Louisa R; Preen, David; Daube, Michael; Kemp, Anna; Einarsdóttir, Kristjana; Randall, Deborah; Tran, Duong Thuy

    2013-01-01

    Introduction Approximately 14% of Australian women smoke during pregnancy. Although the risk of adverse outcomes is reduced by smoking cessation, less than 35% of Australian women quit smoking spontaneously during pregnancy. Evidence for the efficacy of bupropion, varenicline or nicotine replacement therapy as smoking cessation aids in the non-pregnant population suggest that pharmacotherapy for smoking cessation is worth exploring in women of childbearing age. Currently, little is known about the utilisation, effectiveness and safety of pharmacotherapies for smoking cessation during pregnancy; neither the extent to which they are used prior to pregnancy nor whether their use has changed in response to related policy reforms. The Smoking MUMS (Maternal Use of Medications and Safety) Study will explore these issues using linked person-level data for a population-based cohort of Australian mothers. Methods and analysis The cohort will be assembled by linking administrative health records for all women who gave birth in New South Wales or Western Australia since 2003 and their children, including records relating to childbirth, use of pharmaceuticals, hospital admissions, emergency department presentations and deaths. These longitudinal linked data will be used to identify utilisation of smoking cessation pharmacotherapies during and between pregnancies and to explore the associated smoking cessation rates and maternal and child health outcomes. Subgroup and temporal analyses will identify potential differences between population groups including indigenous mothers and social security recipients and track changes associated with policy reforms that have made alternative smoking cessation pharmacotherapies available. Ethics and dissemination Ethical approval has been obtained for this study. To enhance the translation of the project's findings into policy and practice, policy and clinical stakeholders will be engaged through a reference group and a policy forum will be

  11. A TENTATIVE DETECTION OF AN EMISSION LINE AT 1.6 {mu}m FOR THE z {approx} 12 CANDIDATE UDFj-39546284

    SciTech Connect

    Brammer, Gabriel B.; Van Dokkum, Pieter G.; Momcheva, Ivelina; Illingworth, Garth D.; Oesch, Pascal A.

    2013-03-01

    We present deep WFC3 grism observations of the candidate z {approx} 12 galaxy UDFj-39546284 in the Hubble Space Telescope (HST) Ultra Deep Field (UDF), by combining spectroscopic data from the 3D-HST and CANDELS surveys. The total exposure time is 40.5 ks and the spectrum covers 1.10 < {lambda} < 1.65 {mu}m. We search for faint emission lines by cross-correlating the two-dimensional G141 spectrum with the observed H{sub 160} morphology, a technique that is unique to slitless spectroscopy at HST resolution. We find a 2.7{sigma} detection of an emission line at 1.599 {mu}m-just redward of the JH{sub 140} filter-with flux 3.5 {+-} 1.3 Multiplication-Sign 10{sup -18} erg s{sup -1} cm{sup -2}. Assuming that the line is real, it contributes 110% {+-} 40% of the observed H{sub 160} flux and has an observed equivalent width >7300 A. If the line is confirmed, it could be Ly{alpha} at z = 12.12. However, a more plausible interpretation, given current results, could be a lower redshift feature such as [O III]{lambda}4959,5007 at z = 2.19. We find two other 3D-HST [O III] emitters within 1000 km s{sup -1} of that redshift in the GOODS-South field. Additional support for this interpretation comes from the discovery of a bright ''[O III] blob'' with a secure G141 grism redshift of z = 1.605. This object has a strikingly large observed equivalent width of nearly 9000 A that results in similar ''dropout''colors as UDFj-39546284.

  12. Radiative flux calculations at UV and visible wavelengths

    SciTech Connect

    Grossman, A.S.; Grant, K.E.; Wuebbles, D.J.

    1993-10-01

    A radiative transfer model to calculate the short wavelength fluxes at altitudes between 0 and 80 km has been developed at LLNL. The wavelength range extends from 175--735 nm. This spectral range covers the UV-B wavelength region, 250--350 nm, with sufficient resolution to allow comparison of UV-B measurements with theoretical predictions. Validation studies for the model have been made for both UV-B ground radiation calculations and tropospheric solar radiative forcing calculations for various ozone distributions. These studies indicate that the model produces results which agree well with respect to existing UV calculations from other published models.

  13. Optical spectrum evolution induced by altering input light wavelength spacing

    NASA Astrophysics Data System (ADS)

    Wang, Minjie; Ma, Caiwen

    2016-11-01

    This study explored the optical spectrum evolution process using a pump-modulated light and a continuous-wave probe, launched simultaneously into a 1 km highly nonlinear fiber. A total of 70 optical spectra were obtained by each changing the wavelength spacing (0.4 nm) between the probe and pump lights. Simulation results indicated that wavelength spacing between the two beams caused a cyclical optical spectrum evolution process induced by cross-phase modulation. As input light wavelength spacing increased, the coupling between the two optical fields showed obvious attenuation in each neat, multi-peak cycle.

  14. Nonstoichiometric Laser Materials: Designer Wavelengths in Neodymium Doped Garnets

    NASA Technical Reports Server (NTRS)

    Walsh, Brian M.; Barnes, Norman P.

    2008-01-01

    The tunable nature of lasers provides for a wide range of applications. Most applications rely on finding available laser wavelengths to meet the needs of the research. This article presents the concept of compositional tuning, whereby the laser wavelength is designed by exploiting nonstoichiometry. For research where precise wavelengths are required, such as remote sensing, this is highly advantageous. A theoretical basis for the concept is presented and experimental results in spectroscopic measurements support the theoretical basis. Laser operation nicely demonstrates the validity of the concept of designer lasers.

  15. Active Wavelength Control of an External Cavity Quantum Cascade Laser

    PubMed Central

    Tsai, Tracy; Wysocki, Gerard

    2012-01-01

    We present an active wavelength control system for grating-based external cavity lasers that increases the accuracy of predicting the lasing wavelength based on the grating equation and significantly improves scan-to-scan wavelength/frequency repeatability. The ultimate 3σ precision of a frequency scan is determined by the scan-to-scan repeatability of 0.042 cm−1. Since this control method can be applied to any external cavity laser with little to no modification, such a precision provides an excellent opportunity for spectroscopic applications that target molecular absorption lines at standard atmospheric conditions. PMID:23483850

  16. Free-space wavelength-multiplexed optical scanner.

    PubMed

    Yaqoob, Z; Rizvi, A A; Riza, N A

    2001-12-10

    A wavelength-multiplexed optical scanning scheme is proposed for deflecting a free-space optical beam by selection of the wavelength of the light incident on a wavelength-dispersive optical element. With fast tunable lasers or optical filters, this scanner features microsecond domain scan setting speeds and large- diameter apertures of several centimeters or more for subdegree angular scans. Analysis performed indicates an optimum scan range for a given diffraction order and grating period. Limitations include beam-spreading effects based on the varying scanner aperture sizes and the instantaneous information bandwidth of the data-carrying laser beam.

  17. Wavelength resolved specific optical rotations and homochiral equilibria.

    PubMed

    Polavarapu, P L; Covington, C L

    2015-09-01

    The fundamental expressions governing specific optical rotations (SORs) of homochiral systems exhibiting monomer-dimer equilibria are presented. These equations are then utilized with the experimental measurements of wavelength resolved circular birefringence for (R)-(-)-α-hydroxy-β,β-dimethyl-γ-butyrolactone, to determine the wavelength resolved SORs of monomer and dimer components for the first time. Density functional theory predictions on the corresponding dispersion properties of monomer and dimer are found to match with experimentally determined quantities within a factor of ∼2. The wavelength resolved circular birefringence in the liquid solution phase thus provides a powerful means to investigate the molecular properties involved in homochiral equilibria. PMID:26227210

  18. Free-space wavelength-multiplexed optical scanner.

    PubMed

    Yaqoob, Z; Rizvi, A A; Riza, N A

    2001-12-10

    A wavelength-multiplexed optical scanning scheme is proposed for deflecting a free-space optical beam by selection of the wavelength of the light incident on a wavelength-dispersive optical element. With fast tunable lasers or optical filters, this scanner features microsecond domain scan setting speeds and large- diameter apertures of several centimeters or more for subdegree angular scans. Analysis performed indicates an optimum scan range for a given diffraction order and grating period. Limitations include beam-spreading effects based on the varying scanner aperture sizes and the instantaneous information bandwidth of the data-carrying laser beam. PMID:18364951

  19. STED nanoscopy with wavelengths at the emission maximum

    NASA Astrophysics Data System (ADS)

    Bordenave, Martín D.; Balzarotti, Francisco; Stefani, Fernando D.; Hell, Stefan W.

    2016-09-01

    Commonly, in stimulated emission depletion (STED) fluorescence nanoscopy, light of a wavelength located at the red tail of the emission spectrum of the dye is used to shrink the effective fluorophore excitation volume and thus to obtain images with sub diffraction resolution. Here, we demonstrate that continuous wave (CW) STED nanoscopy is feasible using STED wavelengths located at the emission maximum, where the cross section for stimulated emission is up to 10-fold larger than at the red tail. As a result, STED imaging becomes possible at equally lower STED beam power. Besides, fluorophores that have been considered inapplicable in certain wavelength constellations are thus becoming usable.

  20. Light detection and the wavelength shifter deposition in DEAP-3600

    NASA Astrophysics Data System (ADS)

    Broerman, B.; Retière, F.

    2016-02-01

    The Dark matter Experiment using Argon Pulse-shape discrimination (DEAP) uses liquid argon as a target medium to perform a direct-detection dark matter search. The 3600 kg liquid argon target volume is housed in a spherical acrylic vessel and viewed by a surrounding array of photomultiplier tubes. Ionizing particles in the argon volume produce scintillation light which must be wavelength shifted to be detected by the photomultiplier tubes. Argon scintillation and wavelength shifting, along with details on the application of the wavelength shifter to the inner surface of the acrylic vessel are presented.

  1. Experimental demonstration of wavelength domain rogue-free ONU based on wavelength-pairing for TDM/WDM optical access networks.

    PubMed

    Lee, Jie Hyun; Park, Heuk; Kang, Sae-Kyoung; Lee, Joon Ki; Chung, Hwan Seok

    2015-11-30

    In this study, we propose and experimentally demonstrate a wavelength domain rogue-free ONU based on wavelength-pairing of downstream and upstream signals for time/wavelength division-multiplexed optical access networks. The wavelength-pairing tunable filter is aligned to the upstream wavelength channel by aligning it to one of the downstream wavelength channels. Wavelength-pairing is implemented with a compact and cyclic Si-AWG integrated with a Ge-PD. The pairing filter covered four 100 GHz-spaced wavelength channels. The feasibility of the wavelength domain rogue-free operation is investigated by emulating malfunction of the misaligned laser. The wavelength-pairing tunable filter based on the Si-AWG blocks the upstream signal in the non-assigned wavelength channel before data collision with other ONUs.

  2. Broadband telecommunication wavelength emission in Yb(3+)-Er(3+)-Tm(3+) co-doped nano-glassceramics.

    PubMed

    Tikhomirov, V K; Driesen, K; Görller-Walrand, C; Mortier, M

    2007-07-23

    Transparent Yb(3+), Er(3+) and Tm(3+) co-doped nano-glass-ceramics 3(SiO(2)2)9(AlO(1.5))31.5(CdF(2))18.5(PbF(2))5.5(ZnF(2)):3.5(Yb-Er-TmF(3)), mol%, have been prepared where co-dopants mostly partition in nano-crystals Pb(1-x) (Yb(3+),Er(3+),Tm(3+))(x)F(2+x) embedded in the glass network. The Yb(3+) ensures high absorption at 980 nm telecommunication pump wavelength and further phonon-mediated energy transfer to Er(3+) and Tm(3+) co-dopants. Er(3+) and Tm(3+) radiate overlapping emission bands from their lowest energy levels, with similar lifetime of about 9 ms, which cover the range between 1.50 to 1.70 mum. The lifetime of all higher levels of Er(3+) and Tm(3+) dopants is shorter than 70 mus due to short inter-dopant distances in the nano-crystals resulting in fast energy transfer to their lowest levels.

  3. Co{sup 2+}:GGG nonlinear optical crystal for the 1.3 - 1.7 -{mu}m spectral range

    SciTech Connect

    Kravchenko, V B; Sadovskii, Pavel I; Sobolev, A T; Zakharov, L Yu; Sadovskii, S P

    2009-12-31

    A cobalt-doped GGG crystal is grown and its properties are studied. The absorption and fluorescence spectra in the visible and IR regions are measured. The absorption cross sections of the Co{sup 2+} ion in the GGG crystal at a wavelength of 1535 nm are determined for transitions from the ground ({sigma}{sub gs} = 4.8 x 10{sup -20} cm{sup 2}) and metastable states ({sigma}{sub es} = 1.4 x 10{sup -20} cm{sup 2}). Preliminary experimental results on Q-switching of erbium laser radiation by a Co{sup 2+}:GGG passive Q-switch are presented. (active media)

  4. Radiation Effects on Fused Biconical Taper Wavelength Division Multiplexers

    NASA Technical Reports Server (NTRS)

    Gutierrez, Roman C.; Swift, Gary M.; Dubovitsky, Serge; Bartman, Randall K.; Barnes, Charles E.; Dorsky, Leonard

    1994-01-01

    The effects of radiation on fused biconical taper wavelength division multiplexers are presented. A theoretical model indicates that index changes in the fiber are primarily responsible for the degradation of these devices.

  5. High Resolution Imaging of Circumstellar Disks at Millimeter Wavelengths

    NASA Technical Reports Server (NTRS)

    Wilner, David J.

    2004-01-01

    We summarize progress on our program to use high angular resolution imaging of thermal dust continuum emission at millimeter and submillimeter wavelengths to probe the structure of protoplanetary disks and debris disks around nearby stars.

  6. Diffraction cancellation over multiple wavelengths in photorefractive dipolar glasses.

    PubMed

    Parravicini, J; Di Mei, F; Conti, C; Agranat, A J; DelRe, E

    2011-11-21

    We report the simultaneous diffraction cancellation for beams of different wavelengths in out-of-equilibrium dipolar glass. The effect is supported by the photorefractive diffusive nonlinearity and scale-free optics, and can find application in imaging and microscopy.

  7. Long-Wavelength Topographic Change on Mercury: Evidence and Mechanisms

    NASA Astrophysics Data System (ADS)

    Solomon, S. C.; Klimczak, C.; Byrne, P. K.; Hauck, S. A.; Balcerski, J. A.; Dombard, A. J.; Zuber, M. T.; Smith, D. E.; Phillips, R. J.; Head, J. W.; Watters, T. R.

    2012-03-01

    Orbital observations by the MESSENGER spacecraft show that Mercury experienced marked changes in long-wavelength topography more recently than the end of late heavy bombardment and the volcanic emplacement of the largest expanses of smooth plains.

  8. Wavelength division multiplexing. [in fiber optics communication systems

    NASA Technical Reports Server (NTRS)

    Hendricks, H. D.

    1985-01-01

    Wavelength division multiplexing (WDM) represents an approach for expanding the communication capacity and for implementing special data techniques in a fiber optics system. This technology is implemented by adding optical sources of different wavelengths at optical transmitting locations. The present paper is concerned with some of the current efforts in WDM. WDM applications are related to long haul communications, local area data networks, spacecraft and aircraft data systems, fault tolerant computer networks, special sensor devices, high speed data processors, closed circuit and cable television, and submarine cable systems. Attention is given to the current state of wavelength division multiplexing applications, the availability and status of WDM components semiconductor lasers/transmitters, availability and status of fiber optic detectors/receivers, optical fibers/cables/connectors/taps/star couplers, wavelength multiplexers/demultiplexers, and future WDM for local area networks.

  9. Sub-wavelength antenna enhanced bilayer graphene tunable photodetector

    DOEpatents

    Beechem, III, Thomas Edwin; Howell, Stephen W.; Peters, David W.; Davids, Paul; Ohta, Taisuke

    2016-03-22

    The integration of bilayer graphene with an absorption enhancing sub-wavelength antenna provides an infrared photodetector capable of real-time spectral tuning without filters at nanosecond timescales.

  10. Computing the Balmer Wavelengths With a Hand Calculator

    ERIC Educational Resources Information Center

    Sidran, Miriam

    1977-01-01

    Outlines a problem concerning the computation of hydrogen spectral line wavelength in a general physics class which is appropriate for computations on calculators with 8 significant digits of accuracy. (SL)

  11. Characteristic wavelength of textile fiber in near infrared spectroscopy

    NASA Astrophysics Data System (ADS)

    Feng, Hongnian; Jin, Shangzhong; Gan, Bin

    2006-01-01

    Near Infrared (NIR) spectroscopy in the region from 1300 to 1700nm, coupled with multivariate analytic statistical techniques, have been used to predict the chemical properties of textile fiber. Molecule absorbs electromagnetic wave with especial wavelength, which leads to bring characteristic absorption spectrum. Characteristic wavelength is the most important parameter in NIR detection. How to select characteristic wavelength is the key to NIR measure. Different mathematical methods are used to find relationship between the NIR absorption spectrum and the chemical properties of the textile fiber. We adopt stepwise multiple linear regression (SMLR) to select characteristic wavelength. As objective condition is limited, this article only refers to cotton and terylene. By computing correlation coefficient, we establish calibration equation with the smoothed absorbance data. Finally, the bias was controlled under 6%. Then, we find that NIR can be used to carry on qualitative analysis and quantitative analysis of the textile.

  12. Massively sub-wavelength guiding of electromagnetic waves.

    PubMed

    Hooper, I R; Tremain, B; Dockrey, J A; Hibbins, A P

    2014-01-01

    Recently a new form of ultra-thin flexible waveguide consisting of a conducting comb-like structure with a thickness of the order of 1/600(th) of the operating wavelength was presented. However, whilst the thickness of the guide was massively sub-wavelength, the remaining dimensions (the height and period of the comb) were much longer. In this paper we propose, and experimentally verify, that a modified guiding geometry consisting of a chain of ultra-thin conducting spirals allows guiding of electromagnetic waves with wavelengths that are many times (40+) longer than any characteristic dimension of the guide, enabling super-sub-wavelength guiding and localisation of electromagnetic energy.

  13. Influence of three laser wavelengths on human fibroblasts cell culture.

    PubMed

    Crisan, Bogdan; Soritau, Olga; Baciut, Mihaela; Campian, Radu; Crisan, Liana; Baciut, Grigore

    2013-02-01

    Although experimental studies in vitro and vivo have been numerous, the effect of laser wavelength irradiation on human fibroblast cell culture is poorly understood. This emphasizes the need of additional cellular and molecular research into laser influence with low energy and power. The aim of this study was to assess the influence of three different laser wavelengths on the human skin fibroblasts cell culture. We wanted to evaluate if near infrared lasers had any influence in healing of wounds by stimulating mitochondrial activity of fibroblasts. The cells were irradiated using 830-, 980- and 2,940-nm laser wavelengths. The irradiated cells were incubated and their mitochondrial activity was assessed by the MTT assay at 24, 48 and 72 h. Simultaneously, an apoptosis assay was assessed on the irradiated fibroblasts. It can be concluded that laser light of the near-infrared region (830 and 980 nm) influences fibroblasts mitochondrial activity compared to the 2,940-nm wavelength which produces apoptosis.

  14. Stress induced long wavelength photoconductivity in doped silicon infrared detectors

    NASA Technical Reports Server (NTRS)

    Houck, J. R.

    1982-01-01

    The long wavelength cutoff of a Si:P detector was extended to 34 microns by the application of a uniaxial stress. An unstressed Si:P photoconductive detector responds to photons of up to 28 microns wavelength. By applying a uniaxial stress to a detector along the /100/ crystal axis, the response was extended to approximately 34 microns. The /100/ axis was chosen as the stress direction because theoretical calculations predicted that such a stress extends the wavelength response more than one along the /110/ axis. These theoretical calculations were based upon fits to experimental data obtained at stresses of up to approximately kbar, and indicated that the extension in wavelength response continues to increase at much larger stresses.

  15. Dynamic wavelength conversion in copropagating slow-light pulses.

    PubMed

    Kondo, K; Baba, T

    2014-06-01

    Dynamic wavelength conversion (DWC) is obtained by controlling copropagating slow-light signal and control pulse trajectories. Our method is based on the understanding that conventional resonator-based DWC can be generalized, and is linked to cross-phase modulation. Dispersion-engineered Si photonic crystal waveguides produce such slow-light pulses. Free carriers generated by two-photon absorption of the control pulse dynamically shift the signal wavelength. Matching the group velocities of the two pulses enhances the shift, elongating the interaction length. We demonstrate an extremely large wavelength shift in DWC (4.9 nm blueshift) for the signal wavelength. Although DWC is similar to the Doppler effect, we highlight their essential differences. PMID:24949770

  16. Wavelength-Dependent Optical Absorption Properties of Artificial and Atmospheric Aerosol Measured by a Multi-Wavelength Photoacoustic Spectrometer

    NASA Astrophysics Data System (ADS)

    Utry, N.; Ajtai, T.; Pintér, M.; Bozóki, Z.; Szabó, G.

    2014-12-01

    Various aspects of the photoacoustic (PA) detection method are discussed from the point of view of developing it into a routine tool for measuring the wavelength-dependent optical absorption coefficient of artificial and atmospheric aerosol. The discussion includes the issues of calibration, cross-sensitivity to gaseous molecules, background PA signal subtraction, and size-dependent particle losses within the PA system. The results in this paper are based on a recently developed four-wavelength PA system, which has operational wavelengths in the near-infrared, in the visible, and in the ultraviolet. The measured spectra of artificial and atmospheric aerosol prove the outstanding applicability of the presented PA system.

  17. Tunable wavelength terahertz polarization converter based on quartz waveplates.

    PubMed

    Kaveev, A K; Kropotov, G I; Tsypishka, D I; Tzibizov, I A; Vinerov, I A; Kaveeva, E G

    2014-08-20

    We present the results of calculation and experimental testing of the tunable wavelength terahertz polarization converter represented by a set of plane-parallel birefringent plates with an in-plane birefringence axis. An experimental device has been produced and tested. The calculations show that the effect of interference between the interfaces, including air gaps, may be neglected. The considered device may be used as a simple narrow achromatic waveplate, or a Solc band pass filter for the specified wavelength.

  18. Wavelength stabilized multi-kW diode laser systems

    NASA Astrophysics Data System (ADS)

    Köhler, Bernd; Unger, Andreas; Kindervater, Tobias; Drovs, Simon; Wolf, Paul; Hubrich, Ralf; Beczkowiak, Anna; Auch, Stefan; Müntz, Holger; Biesenbach, Jens

    2015-03-01

    We report on wavelength stabilized high-power diode laser systems with enhanced spectral brightness by means of Volume Holographic Gratings. High-power diode laser modules typically have a relatively broad spectral width of about 3 to 6 nm. In addition the center wavelength shifts by changing the temperature and the driving current, which is obstructive for pumping applications with small absorption bandwidths. Wavelength stabilization of high-power diode laser systems is an important method to increase the efficiency of diode pumped solid-state lasers. It also enables power scaling by dense wavelength multiplexing. To ensure a wide locking range and efficient wavelength stabilization the parameters of the Volume Holographic Grating and the parameters of the diode laser bar have to be adapted carefully. Important parameters are the reflectivity of the Volume Holographic Grating, the reflectivity of the diode laser bar as well as its angular and spectral emission characteristics. In this paper we present detailed data on wavelength stabilized diode laser systems with and without fiber coupling in the spectral range from 634 nm up to 1533 nm. The maximum output power of 2.7 kW was measured for a fiber coupled system (1000 μm, NA 0.22), which was stabilized at a wavelength of 969 nm with a spectral width of only 0.6 nm (90% value). Another example is a narrow line-width diode laser stack, which was stabilized at a wavelength of 1533 nm with a spectral bandwidth below 1 nm and an output power of 835 W.

  19. Coupling polariton quantum boxes in sub-wavelength grating microcavities

    SciTech Connect

    Zhang, Bo; Wang, Zhaorong; Deng, Hui; Brodbeck, Sebastian; Kamp, Martin; Schneider, Christian; Höfling, Sven

    2015-02-02

    We report the construction of decoupled, coupled, and quasi-one dimensional polariton systems from zero dimensional polariton quantum boxes using microcavities with sub-wavelength gratings as the top mirror. By designing the tethering patterns around the suspended sub-wavelength gratings, we control the coupling between individual quantum boxes through different optical potentials. Energy levels and real-space or momentum space distributions of the confined modes were measured, which agreed well with simulations.

  20. Production of plasmas by long-wavelength lasers

    DOEpatents

    Dawson, J.M.

    1973-10-01

    A long-wavelength laser system for heating low-density plasma to high temperatures is described. In one embodiment, means are provided for repeatedly receiving and transmitting long-wavelength laser light in successive stages to form a laser-light beam path that repeatedly intersects with the equilibrium axis of a magnetically confined toroidal plasma column for interacting the laser light with the plasma for providing controlled thermonuclear fusion. Embodiments for heating specific linear plasmas are also provided. (Official Gazette)