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. 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)

  3. 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.

  4. Peltier-Cooled and Actively Quenched Operation of InGaAs/InP Avalanche Photodiodes as Photon Counters at a 1.55-mum Wavelength.

    PubMed

    Prochazka, I

    2001-11-20

    The performance of commercially available InGaAs/InP avalanche photodiodes as single-photon detectors at a 1.55-mum wavelength has been investigated. A new active quenching and gating circuit, tailored for operation of these diodes at temperatures in the range from room temperature to -60 degrees C and achievable by means of thermoelectrical cooling, has been developed. Careful tuning of the diodes' operating conditions resulted in a significant reduction of afterpulsing effects; it permitted operation of the detectors with high repetition rates. A noise-equivalent power of 7 x 10(-16) W/Hz(1/2) was obtained at a 1.55-mum wavelength.

  5. Photorefractive effect in iron-doped lithium niobate crystals induced by femtosecond pulses of 1.5 {mu}m wavelength

    SciTech Connect

    Beyer, O.; Breunig, I.; Kalkum, F.; Buse, K.

    2006-01-30

    Illumination of iron-doped lithium crystals (LiNbO{sub 3}:Fe) with femtosecond pulses of 1.5 {mu}m wavelength results in large refractive index changes {delta}n in the order of 10{sup -3}. The sign of the refractive index changes depends on the polarization of the recording light. The results can be very useful for fabrication of tailored holographic components for telecommunication.

  6. Mapping of cerebro-vascular blood perfusion in mice with skin and skull intact by Optical Micro-AngioGraphy at 1.3 mum wavelength.

    PubMed

    Wang, Ruikang K; Hurst, Sawan

    2007-09-03

    Optical micro-angiography (OMAG) was developed to achieve volumetric imaging of the microstructures and dynamic cerebrovascular blood perfusion in mice with capillary level resolution and high signal-to-background ratio. In this paper, we present a high-speed and high-sensitivity OMAG imaging system by using an InGaAs line scan camera and broadband light source at 1.3 mum wavelength for enhanced imaging depth in tissue. We show that high quality imaging of cerebrovascular blood perfusion down to capillary level resolution with the intact skin and cranium are obtained in vivo with OMAG, without the interference from the blood perfusion in the overlaying skin. The results demonstrate the potential of 1.3 mum OMAG for high-speed and high-sensitivity imaging of blood perfusion in human and small animal studies.

  7. Four-frequency polarizing microscope for recording plasma images in the wavelength range 0.4-1.1 {mu}m

    SciTech Connect

    Vasin, B. L.; Mal'kova, S. V.; Osipov, M. V.; Puzyrev, V. N.; Saakyan, A. T.; Starodub, A. N.; Fedotov, S. I.; Fronya, A. A.; Shutyak, V. G.

    2010-12-15

    The optical scheme and design of a four-frequency polarizing microscope intended for simultaneous recording of plasma images in the wavelength range 0.4-1.1 {mu}m with the spatial resolution 12 {mu}m in the entire spectral range are described. The effectiveness of such a microscope in studies of plasmas produced on interaction of laser radiation with a target is demonstrated. The plasma images are obtained at the frequencies {omega}{sub 0}, (3/2){omega}{sub 0}, 2{omega}{sub 0}, and (5/2){omega}{sub 0}, where {omega}{sub 0} corresponds to the frequency of heating radiation. The transformation coefficient that characterizes the efficiency of conversion of heating radiation into the 2{omega}{sub 0}, (3/2){omega}{sub 0}, and (5/2){omega}{sub 0} harmonics generated in the plasma is determined.

  8. 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)

  9. 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

  10. 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.

  11. 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.

  12. FAINT SUBMILLIMETER GALAXY COUNTS AT 450 {mu}m

    SciTech Connect

    Chen, Chian-Chou; Cowie, Lennox L.; Barger, Amy J.; Casey, Caitlin M.; Lee, Nicholas; Sanders, David B.; Williams, Jonathan P.; Wang, Wei-Hao

    2013-01-10

    We present the results of SCUBA-2 observations at 450 {mu}m and 850 {mu}m of the field lensed by the massive cluster A370. With a total survey area >100 arcmin{sup 2} and 1{sigma} sensitivities of 3.92 and 0.82 mJy beam{sup -1} at 450 and 850 {mu}m, respectively, we find a secure sample of 20 sources at 450 {mu}m and 26 sources at 850 {mu}m with a signal-to-noise ratio (S/N) > 4. Using the latest lensing model of A370 and Monte Carlo simulations, we derive the number counts at both wavelengths. The 450 {mu}m number counts probe a factor of four deeper than the counts recently obtained from the Herschel Space Telescope at similar wavelengths, and we estimate that {approx}47%-61% of the 450 {mu}m extragalactic background light resolved into individual sources with 450 {mu}m fluxes greater than 4.5 mJy. The faint 450 {mu}m sources in the 4{sigma} sample have positional accuracies of 3 arcsec, while brighter sources (S/N >6{sigma}) are good to 1.4 arcsec. Using a deep radio map (1{sigma} {approx} 6 {mu}Jy) we find that the percentage of submillimeter sources having secure radio counterparts is 85% for 450 {mu}m sources with intrinsic fluxes >6 mJy and 67% for 850 {mu}m sources with intrinsic fluxes >4 mJy. We also find that 67% of the >4{sigma} 450 {mu}m sources are detected at 850 {mu}m, while the recovery rate at 450 {mu}m of >4{sigma} 850 {mu}m sources is 54%. Combined with the source redshifts estimated using millimetric flux ratios, the recovered rate is consistent with the scenario where both 450 {mu}m and 20 cm emission preferentially select lower redshift dusty sources, while 850 {mu}m emission traces a higher fraction of dusty sources at higher redshifts. We identify potential counterparts in various wavelengths from X-ray to mid-infrared and measure the multiwavelength photometry, which we then use to analyze the characteristics of the sources. We find three X-ray counterparts to our robust submillimeter sample (S/N > 5), giving an active galactic nucleus

  13. 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.

  14. Ultra-wideband design of waveguide magneto-optical isolator operating in 1.31mum and 1.55mum band.

    PubMed

    Shoji, Yuya; Mizumoto, Tetsuya

    2007-01-22

    The design of an ultra-wideband waveguide magneto-optical isolator is described. The isolator is based on a Mach-Zehnder interferometer employing nonreciprocal phase shift. The ultra-wideband design is realized by adjusting the wavelength dependence of reciprocal phase difference to compensate for that of nonreciprocal phase difference in the backward direction. We obtained the ultra-wideband design that provides isolation > 35dB from 1.25mum to >1.65mum. This is the proposal of magneto-optical isolator that operates both in 1.31mum band and 1.55mum band.

  15. Magnificent Mum Education Program Featuring the Mum Kids (Grades 4-5).

    ERIC Educational Resources Information Center

    Kelleher, Christine, Ed.

    Magnificent Mum Education Program is a theme-based program developed around the garden mum. With its bright colors, various flower forms, perennial life cycle, and easy propagation, the garden mum is ideal for classroom use and community planting programs. The mum-theme lessons can be integrated into all subject areas including science, math,…

  16. Magnificent Mum Education Program Featuring the Mum Kids (Grades 2-3).

    ERIC Educational Resources Information Center

    Kelleher, Christine, Ed.

    The Magnificent Mum Education Program is a theme-based program developed around the garden mum. With its bright colors, various flower forms, perennial life cycle, and easy propagation, the garden mum is ideal for classroom use and community planting programs. The mum-theme lessons can be integrated into all subject areas including science, math,…

  17. Hybrid Er/Yb fibre laser system for generating few-cycle 1.6 to 2.0 {mu}m pulses optically synchronised with high-power pulses near 1 {mu}m

    SciTech Connect

    Andrianov, A V; Anashkina, E A; Murav'ev, S V; Kim, A V

    2013-03-31

    This paper presents the concept of fibre laser system design for generating optically synchronised femtosecond pulses at two, greatly differing wavelengths and reports experimental and numerical simulation studies of nonlinear conversion of femtosecond pulses at 1.5 {mu}m wavelength in a dispersion-shifted fibre, with the generation of synchronised pulses in the ranges 1.6 - 2 and 1 - 1.1 {mu}m. We describe a three-stage high-power fibre amplifier of femtosecond pulses at 1 {mu}m and a hybrid Er/Yb fibre laser system that has enabled the generation of 12 fs pulses with a centre wavelength of 1.7 {mu}m, synchronised with high-power (microjoule level) 250 fs pulses at 1.03 {mu}m. (extreme light fields and their applications)

  18. 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.

  19. 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.}

  20. THE 15-20 {mu}m EMISSION IN THE REFLECTION NEBULA NGC 2023

    SciTech Connect

    Peeters, Els; Tielens, Alexander G. G. M.; Allamandola, Louis J.; Wolfire, Mark G. E-mail: tielens@strw.leidenuniv.nl E-mail: mwolfire@astro.umd.edu

    2012-03-01

    We present 15-20 {mu}m spectral maps toward the reflection nebula NGC 2023 obtained with the Infrared Spectrograph in short-wavelength, high-resolution mode on board the Spitzer Space Telescope. These spectra reveal emission from polycyclic aromatic hydrocarbons (PAHs), C{sub 60}, and H{sub 2} superposed on a dust continuum. These emission components exhibit distinct spatial distributions: with increasing distance from the illuminating star, we observe the PAH emission followed by the dust continuum emission and the H{sub 2} emission. The C{sub 60} emission is located closest to the illuminating star in the south, while in the north it seems to be associated with the H/H{sub 2} transition. Emission from PAHs and PAH-related species produces features at 15.8, 16.4, 17.4, and 17.8 {mu}m and the 15-18 {mu}m plateau. These different PAH features show distinct spatial distributions. The 15.8 {mu}m band and 15-18 {mu}m plateau correlate with the 11.2 {mu}m PAH band and with each other, and are attributed to large, neutral PAHs. Conversely, the 16.4 {mu}m feature correlates with the 12.7 {mu}m PAH band, suggesting that both arise from species that are favored by the same conditions that favor PAH cations. The PAH contribution to the 17.4 {mu}m band is displaced toward the illuminating star with respect to the 11.2 and 12.7 {mu}m emission and is assigned to doubly ionized PAHs and/or a subset of cationic PAHs. The spatial distribution of the 17.8 {mu}m band suggests that it arises from both neutral and cationic PAHs. In contrast to their intensities, the profiles of the PAH bands and the 15-18 {mu}m plateau do not vary spatially. Consequently, we conclude that the carrier of the 15-18 {mu}m plateau is distinct from that of the PAH bands.

  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. SPITZER MIPS 24 and 70 {mu}m IMAGING NEAR THE SOUTH ECLIPTIC POLE: MAPS AND SOURCE CATALOGS

    SciTech Connect

    Scott, Kimberly S.; Stabenau, Hans F.; Devlin, Mark J.; Truch, Matthew D. P.; Braglia, Filiberto G.; Chapin, Edward L.; Marsden, Gaelen; Scott, Douglas; Valiante, Elisabetta; Borys, Colin; Viero, Marco P.

    2010-12-15

    We have imaged an 11.5 deg{sup 2} region of sky toward the South Ecliptic Pole (R.A. =04{sup h}43{sup m}, decl. =-53{sup 0}40', J2000) at 24 and 70 {mu}m with MIPS, the Multiband Imaging Photometer for Spitzer. This region is coincident with a field mapped at longer wavelengths by AKARI and BLAST. We discuss our data reduction and source extraction procedures. The median 1{sigma} depths of the maps are 47 {mu}Jy beam{sup -1} at 24 {mu}m and 4.3 mJy beam{sup -1} at 70 {mu}m. At 24 {mu}m, we identify 93,098 point sources with signal-to-noise ratio (S/N) {>=}5 and an additional 63 resolved galaxies; at 70 {mu}m we identify 891 point sources with S/N {>=}6. From simulations, we determine a false detection rate of 1.8% (1.1%) for the 24 {mu}m (70 {mu}m) catalog. The 24 and 70 {mu}m point-source catalogs are 80% complete at 230 {mu}Jy and 11 mJy, respectively. These mosaic images and source catalogs will be available to the public through the NASA/IPAC Infrared Science Archive.

  3. 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.

  4. THE CONTRIBUTION OF THERMALLY-PULSING ASYMPTOTIC GIANT BRANCH AND RED SUPERGIANT STARS TO THE LUMINOSITIES OF THE MAGELLANIC CLOUDS AT 1-24 {mu}m

    SciTech Connect

    Melbourne, J.; Boyer, Martha L. E-mail: martha.l.boyer@nasa.gov

    2013-02-10

    We present the near-through mid-infrared flux contribution of thermally-pulsing asymptotic giant branch (TP-AGB) and massive red supergiant (RSG) stars to the luminosities of the Large and Small Magellanic Clouds (LMC and SMC, respectively). Combined, the peak contribution from these cool evolved stars occurs at {approx}3-4 {mu}m, where they produce 32% of the SMC light, and 25% of the LMC flux. The TP-AGB star contribution also peaks at {approx}3-4 {mu}m and amounts to 21% in both galaxies. The contribution from RSG stars peaks at shorter wavelengths, 2.2 {mu}m, where they provide 11% of the SMC flux, and 7% for the LMC. Both TP-AGB and RSG stars are short lived, and thus potentially impose a large stochastic scatter on the near-IR derived mass-to-light (M/L) ratios of galaxies at rest-frame 1-4 {mu}m. To minimize their impact on stellar mass estimates, one can use the M/L ratio at shorter wavelengths (e.g., at 0.8-1 {mu}m). At longer wavelengths ({>=}8 {mu}m), emission from dust in the interstellar medium dominates the flux. In the LMC, which shows strong polycyclic aromatic hydrocarbon (PAH) emission at 8 {mu}m, TP-AGB and RSG contribute less than 4% of the 8 {mu}m flux. However, 19% of the SMC 8 {mu}m flux is from evolved stars, nearly half of which is produced by the rarest, dustiest, carbon-rich TP-AGB stars. Thus, star formation rates of galaxies, based on an 8 {mu}m flux (e.g., observed-frame 24 {mu}m at z = 2), may be biased modestly high, especially for galaxies with little PAH emission.

  5. 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…

  6. 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…

  7. A Stress Control Workbook for Youth Grades 6-12.

    ERIC Educational Resources Information Center

    Trotter, Jennie C.

    Stress is an inevitable part of students' lives, but too much stress can have damaging consequences. Ways in which children can respond positively are covered in this stress booklet. Intended for students in grades 6-12, the booklet is divided into 20 lessons on stress. Each lesson features various activities, role plays, exercises, and checklists…

  8. Career and Technology Education Grades 6-12. Program Evaluation.

    ERIC Educational Resources Information Center

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

    Technology education programs are offered in 10 middle schools, 5 area high schools, 1 alternative high school, and at Central Campus in the Des Moines Independent Community School District. Programs in grades 6-12 consist of hands-on instruction using activities and projects as the medium for teaching modern technologies in the various trades.…

  9. Thulium:ZBLAN blue fiber laser pumped by two wavelengths.

    PubMed

    Tohmon, G; Sato, H; Ohya, J; Uno, T

    1997-05-20

    We demonstrate and analyze an upconversion blue fiber laser pumped by two wavelengths. Lasing at 0.48 mum with very low pump threshold power is obtained from a Tm-doped fluorozirconate fiber that is counterpropagating pumped by 1.21- and 0.649-mum light. We employed a rate-equation analysis using parameters obtained by fitting to the experimental data to predict the 0.48-mum output characteristics as a function of fiber length and output reflectivity.

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

    PubMed

    2016-03-04

    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.

  11. High-frequency-stability laser at 1.5 {mu}m using Doppler-free molecular lines

    SciTech Connect

    Labachelerie, M.d.; Nakagawa, K.; Awaji, Y.; Ohtsu, M.

    1995-03-15

    An extended-cavity 1.5-{mu}m semiconductor laser was frequency stabilized to saturated-absorption lines of acetylene. Its long-term frequency stability is of the order of 10{sup --12}, with a reproducibility of {plus_minus}10 kHz. Using the lines of C{sub 2}H{sub 2} or HCN, we could obtain such a high stability with the same laser at many wavelengths covering the 1.51--1.56-{mu}m band.

  12. Electronic speckle pattern interferometry and digital holographic interferometry with microbolometer arrays at 10.6 {mu}m

    SciTech Connect

    Vandenrijt, Jean-Francois; Georges, Marc P.

    2010-09-20

    Electronic speckle pattern interferometry and digital holographic interferometry are investigated at long infrared wavelengths. Using such wavelengths allows one to extend the measurement range and decrease the sensitivity of the techniques to external perturbations. We discuss the behavior of reflection by the object surfaces due to the long wavelength. We have developed different experimental configurations associating a CO2 laser emitting at 10.6{mu}m and microbolometer arrays. Phase-shifting in-plane and out-of-plane electronic speckle pattern interferometry and lensless digital holographic interferometry are demonstrated on rotation measurements of a solid object.

  13. 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)

  14. [Oral hygiene customs in 6-12 year old schoolchildren].

    PubMed

    Hernández-Martínez, César Tadeo; Medina-Solís, Carlo Eduardo; Robles-Bermeo, Norma Leticia; Mendoza-Rodríguez, Martha; Veras-Hernández, Miriam; De la Rosa-Santillana, Rubén; Escoffié-Ramírez, Mauricio; Márquez-Rodríguez, Sonia

    2014-01-01

    OBJECTIVE. To characterize utilization of oral hygiene devices and customs in schoolchildren. MATERIAL AND METHODS. We performed a cross-sectional study in 1,404 schoolchildren (6- 12 year olds) from 14 public schools in Pachuca, Hidalgo, México, using a questionnaire for sociodemographic variables and 1) Tooth brushing frequency (<1/d vs. at least 1/d), 2) Use of toothpaste (not always vs. always), 3) Flossing (never, does not know vs. at least 1/week), 4) Use of mouthwash (never, does not know vs. at least 1/week). Analyses were performed with nonparametric tests. RESULTS. Mean age was 8.97 ± 1.99 years; 50.1% were male. Prevalence of utilization of oral hygiene devices and associated customs were 85.5% tooth brushing, 90.9% toothpaste, 19.4% flossing, and 28.2% mouthwash. Only 11.8% of participants reported utilization in all 4 categories. We observed differences (p < 0.05) across sexes only in the use of toothpaste, as women used it more often. Differences across age were observed (p < 0.05) for tooth brushing (younger children brushed more often) and flossing (older children flossed more often). CONCLUSIONS. Tooth brushing was the oral hygiene practice more often performed in this sample, with other frequencies being relatively low. There were differences by age and sex across some variables.

  15. FREQUENT EXPRESSION OF MUM1/IRF4 IN BURKITT LYMPHOMA

    PubMed Central

    Gualco, Gabriela; Queiroga, Eduardo M.; Weiss, Lawrence M.; Klumb, Claudete E. N.; Harrington, William J.; Bacchi, Carlos E.

    2009-01-01

    Burkitt lymphoma (BL) is a highly aggressive non-Hodgkin lymphoma (NHL) with endemic, sporadic and immunodeficiency-associated clinical variants composed of monomorphic medium-size B-cells with a high proliferation rate and a translocation involving the C-MYC locus. Classically the immunophenotype of Burkitt lymphoma has been considered to be of germinal center type. In most reports, all cases of BL are reported to be MUM1 negative. MUM1 expression is seen in plasma cells and in a small fraction of B cells located in the light zone of germinal centers corresponding to the final step of intra-germinal center (GC) B-cell differentiation, and in activated T-cells. Therefore, MUM1 expression may denote the final step of intra-GC B-cell differentiation at centrocyte stage, as well as the subsequent steps of B-cell maturation towards plasma cells. Unlike most normal GC B-cells, in which the expression of MUM1 and bcl-6 are mutually exclusive, the tumor cells in approximately 50% of MUM1 positive DLBCL show co-expression of bcl-6, suggesting that the expression of these proteins may be deregulated. In one of the few studies in the literature, 25 BL-cases, including 19 associated with HIV; two of these cases showed occasional MUM1+ cells, less than the 20% cut-off for positivity. We studied 222 cases of well-characterized Burkitt lymphoma with the classic phenotype and C-MYC translocation, and found 90 cases (40.5%) with MUM1 nuclear expression suggesting a late germinal center stage of differentiation. PMID:19144381

  16. 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.

  17. DETECTION OF THE 3.3 {mu}m AROMATIC FEATURE IN THE SUPERNOVA REMNANT N49 WITH AKARI

    SciTech Connect

    Seok, Ji Yeon; Koo, Bon-Chul; Onaka, Takashi

    2012-01-10

    We present an infrared (IR) study of the supernova remnant (SNR) N49 in the Large Magellanic Cloud with the near-IR (NIR; 2.5-5 {mu}m) spectroscopic observations performed by AKARI. The observations were performed as a coarse spectral mapping to cover most of the bright region in the east, which enables us to compare the distribution of various line emissions and to examine their correlation. We detect the 3.3 {mu}m aromatic feature in the remnant, which is the first time the presence of the 3.3 {mu}m aromatic feature related to an SNR has been reported. In the line maps of the H{sub 2} 1-0 O(3), the 3.3 {mu}m feature, and the Br{alpha}, the distribution of the aromatic feature shows overall correlation with those of other emissions together with regional differences that reflect the local physical conditions. By comparing other archival imaging data at different wavelengths, the association of the aromatic emission with other ionic/molecular emissions is clarified. We examine the archival Spitzer Infrared Spectrograph data of N49 and find signatures of other polycyclic aromatic hydrocarbon (PAH) features at 6.2, 7.7, and 11.3 {mu}m corresponding to the 3.3 {mu}m aromatic feature. Based on the band ratios of the PAHs, we find that the PAHs in N49 are not only dominantly neutral, but they are also small in size. We discuss the origin of the PAH emission in N49 and conclude that the emission is either from the PAHs that have survived the shock or from the PAHs in the preshock gas that was heated by the radiative precursor.

  18. 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...

  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. 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...

  1. 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...

  2. 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...

  3. Thulium:ZBLAN blue fiber laser pumped by two wavelengths

    SciTech Connect

    Tohmon, G.; Sato, H.; Ohya, J.; Uno, T.

    1997-05-01

    We demonstrate and analyze an upconversion blue fiber laser pumped by two wavelengths. Lasing at 0.48 {mu}m with very low pump threshold power is obtained from a Tm-doped fluorozirconate fiber that is counterpropagating pumped by 1.21- and 0.649-{mu}m light. We employed a rate-equation analysis using parameters obtained by fitting to the experimental data to predict the 0.48-{mu}m output characteristics as a function of fiber length and output reflectivity. {copyright} 1997 Optical Society of America

  4. 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.

  5. 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.

  6. 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.

  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, 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...

  9. 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...

  10. 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…

  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.

  12. Baseband integrated acousto-optic frequency shifter/modulator module for fiber optic at 1.3 mum.

    PubMed

    Tsai, C S; Cheng, Z Y

    1993-01-01

    A baseband integrated acoustooptic (AO) frequency shifter/modulator module that consists of a pair of titanium-indiffused proton-exchanged (TIPE) waveguide lenses and a pair of cascaded guided-wave AO Bragg cells has been realized in a Y-cut LiNbO(3) waveguide substrate 0.1 cmx1.0 cmx2.0 cm in size. A device module operating at the optical wavelength of 1.3 mum has provided a -3-dB tunable bandwidth of 120 MHz at baseband. The frequency-shifted or -modulated light propagates in a fixed direction, irrespective of the magnitude of frequency shift or modulation, and is focused into a spot (FWHM) of 6.2-mum size on the output edge of the waveguide. Accordingly, this optical frequency shifter/module can be directly interfaced with single-mode optical fibers to facilitate applications in fiber optic systems.

  13. 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.

  14. SPECTROSCOPICALLY SELECTED SPITZER 24 {mu}m ACTIVE GALACTIC NUCLEI

    SciTech Connect

    Choi, P. I.; Yan Lin; Helou, G.; Storrie-Lombardi, L. J.; Shim, H.; Fadda, D.; Im, M.

    2011-05-01

    We investigate the active galactic nucleus (AGN) sub-population of a 24 {mu}m flux-limited galaxy sample in the Spitzer Extragalactic First Look Survey. Using deep Keck optical spectroscopy and a series of emission-line diagnostics, we identify AGN-dominated systems over broad redshift 0 < z < 3.5 and luminosity 9 < log (L{sub TIR}) < 14 ranges, with sample means of (z) = 0.85 and (log (L{sub TIR})) = 11.5. We find that down to the flux limits of our Spitzer MIPS sample (f{sub 24} > 200 {mu}Jy), 15%-20% of sources exhibit strong AGN signatures in their optical spectra. At this flux limit, the AGN population accounts for as much as 25%-30% of the integrated 24 {mu}m flux. This corresponds to an MIR AGN contribution {approx}2-3 x greater than that found in ISOCAM 15 {mu}m studies that used X-ray AGN identifications. Based on our spectroscopically selected AGN sample, we also investigate the merits of Infrared Array Camera (IRAC) color selection for AGN identification. Our comparison reveals that although there is considerable overlap, a significant fraction of spectroscopic AGNs are not identifiable based on their MIR colors alone. Both the measured completeness and reliability of the IRAC color selections are found to be strongly dependent on the MIR flux limit. Finally, our spectroscopic AGN sample implies as much as a 3 x higher AGN surface density at high redshift (z > 1.2) than that of recent optical surveys at comparable optical flux limits, suggestive of a population of heavily obscured, optical/UV reddened AGNs.

  15. 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.

  16. 21 CFR 516.29 - Termination of MUMS-drug designation.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...) The sponsor of a MUMS-designated drug must notify FDA of any decision to discontinue active pursuit of... such notification. (c) MUMS designation shall terminate upon the expiration of any applicable period of... approval or approval of the drug's application. (h) Where a drug has been MUMS-designated for a minor...

  17. Nodes, networks, and MUMs: Preserving diversity at all scales

    NASA Astrophysics Data System (ADS)

    Noss, Reed F.; Harris, Larry D.

    1986-05-01

    The present focus of practical conservation efforts is limited in scope. This narrowness results in an inability to evaluate and manage phenomena that operate at large spatiotemporal scales. Whereas real ecological phenomena function in a space-time mosaic across a full hierarchy of biological entities and processes, current conservation strategies address a limited spectrum of this complexity. Conservation typically is static (time-limited), concentrates on the habitat content rather than the landscape context of protected areas, evaluates relatively homogeneous communities instead of heterogeneous landscapes, and directs attention to particular species populations and/or the aggregate statistic of species diversity. Insufficient attention has been given to broad ecological patterns and processes and to the conservation of species in natural relative abundance patterns (native diversity). The authors present a conceptual scheme that evaluates not only habitat content within protected areas, but also the landscape context in which each preserve exists. Nodes of concentrated ecological value exist in each landscape at all levels in the biological hierarchy. Integration of these high-quality nodes into a functional network is possible through the establishment of a system of interconnected multiple-use modules (MUMs). The MUM network protects and buffers important ecological entities and phenomena, while encouraging movement of individuals, species, nutrients, energy, and even habitat patches across space and time. An example is presented for the southeastern USA (south Georgia-north Florida), that uses riparian and coastal corridors to interconnect existing protected areas. This scheme will facilitate reintroduction and preservation of wide-ranging species such as the Florida panther, and help reconcile species-level and ecosystem-level conservation approaches.

  18. X-ray backlighting characterization experiments performed with laser wavelengths of 1. 06, 0. 53, and 0. 35. mu. m

    SciTech Connect

    Matthews, D.L.; Campbell, E.M.; Ceglio, N.

    1982-01-01

    We report the conversion efficiency, xi/sub x/, for production of x-ray backlighting line sources from 1.4 keV to 8.6 keV as a function of laser wavelength, -pulselength and intensity. For K-shell x-ray line emission we observed only a moderate increase in xi/sub x/ when using a 0.35..mu..m (instead of 1.06 ..mu..m) wavelength laser.

  19. Reflection Coefficients for Wires and Cables at 106 mum.

    PubMed

    Hayes, C L; Brandewie, R A

    1973-07-01

    Measurements are given of the reflectivity coefficient for a variety of wires and cables at 10.6 mum. The results are presented as a function of wire incidence angle for two polarizations, parallel and perpendicular to the samples. The normal incidence reflectivity is very high, ranging from 610% for aluminum wire down to 16.8% for hemp rope in parallel polarization. The perpendicular polarization results are lower by a factor that varied from 5.9 to 2.04. Depolarization by the wires was also determined. The depolarization ratio was found to vary between 17.7% and 1%, being larger for the more irregular samples. The results indicate that a wire avoidance system could be developed for airplanes or helicopters using a scanning 10.6 microm laser and coherent receiver. The power required for such an application is estimated from the data and is found to be relatively low, only 28 W being required to cover a 20 degrees x 90 degrees field in 1 sec.

  20. 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

  1. Effect of laser radiation absorption in water and blood on the optimal wavelength for endovenous obliteration of varicose veins

    SciTech Connect

    Zhilin, K M; Minaev, V P; Sokolov, Aleksandr L

    2009-08-31

    This work examines laser radiation absorption in water and blood at the wavelengths that are used in endovenous laser treatment (EVLT): 0.81-1.06, 1.32, 1.47, 1.5 and 1.56 {mu}m. It is shown that the best EVLT conditions are ensured by 1.56-{mu}m radiation. Analysis of published data suggests that even higher EVLT efficacy may be achieved at wavelengths of 1.68 and 1.7 {mu}m. (laser medicine)

  2. 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.

  3. INFRARED SPECTROSCOPY OF GAS-PHASE POLYCYCLIC AROMATIC HYDROCARBON CATIONS IN THE 10-50 {mu}m SPECTRAL RANGE

    SciTech Connect

    Bakker, Joost M.; Redlich, Britta; Van der Meer, Alexander F. G.; Oomens, Jos

    2011-11-10

    The gas-phase infrared spectra of four polycyclic aromatic hydrocarbon (PAH) cations have been recorded in the 10-50 {mu}m (or 1000-200 cm{sup -1}) spectral range via IR multiple photon dissociation (IRMPD) spectroscopy. Ionized PAHs are formed by UV laser ionization in an effusive beam and subsequently irradiated with a single pulse of narrowband tunable infrared light produced by the Free-Electron Laser for IntraCavity Experiments FELICE. The ion population is then analyzed in a time-of-flight mass spectrometer. Upon resonance, dissociation is induced so that IR spectra can be recorded by monitoring either the depleted parent ion intensity or the appearance of fragment ions as a function of the wavelength. The intracavity IR fluence enables the recording of IRMPD spectra of strongly bound PAH cations in the hitherto inaccessible far-IR spectral range. Experimental spectra are presented for the radical cations of anthracene, tetracene, pentacene, and coronene. Spectra calculated with density functional theory at the B3LYP/6-311g(2df,2pd) level reproduce IR frequencies reasonably accurately in this spectral range when a uniform scaling factor of 0.94 over the complete 10-50 {mu}m spectral range is employed. We show that even vibrational modes with a calculated IR intensity lower than 1 km mol{sup -1} can be observed. For the catacondensed PAH cations we find CH out-of-plane bending vibrations involving four adjacent CH groups within a few wavenumbers of 733 cm{sup -1}, closely matching the 13.6 {mu}m UIR band. For the larger systems, pentacene and coronene, we observe a continuous structureless background absorption above 400 cm{sup -1} which is attributed to the high density of IR dipole allowed combination modes for these systems.

  4. Teaching Global Awareness with Simulations and Games. Grades 6-12. Global Awareness Series.

    ERIC Educational Resources Information Center

    Lamy, Steven L.; And Others

    This teaching guide contains 15 simulation/games for students in grades 6-12 on the topic of global awareness. The overall objective is to help students understand various global concepts and social studies content. Specifically, it gives students the chance to experience and understand international/intercultural situations which involve people…

  5. 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…

  6. 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…

  7. 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,…

  8. West Nile virus activity--United States, October 6-12, 2004.

    PubMed

    2004-10-15

    During October 6-12, a total of 86 cases of human West Nile virus (WNV) illness were reported from 18 states (Arizona, Florida, Illinois, Kansas, Louisiana, Michigan, Minnesota, Missouri, Nevada, New Jersey, New Mexico, North Dakota, Ohio, Oklahoma, Pennsylvania, Tennessee, Texas, and Utah).

  9. More Novels and Plays: Thirty Creative Teaching Guides for Grades 6-12.

    ERIC Educational Resources Information Center

    Worthington, Janet E.; Somers, Albert B.

    This companion volume to "Novels and Plays" contains 30 detailed teaching guides for some of the best literature commonly taught in grades 6-12. Twenty of the guides are new to this edition and the others have been updated with fresh related readings, extension resources, and revised questions and activities. Guides are organized according to the…

  10. Teaching Global Awareness Using the Media. Grades 6-12, Global Awareness Series.

    ERIC Educational Resources Information Center

    Lamy, Steven L.; And Others

    This teaching guide on global awareness contains 15 media-related activities for students in grades 6-12. The objective is to help students see how the media affect their opinions and the roles the media plays in world affairs. The activities are divided into five sections. The first section contains a general survey of the students' knowledge of…

  11. 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…

  12. Language Arts Grades 6-12 Program Evaluation, 1996-97.

    ERIC Educational Resources Information Center

    Wadden, Jerry M.

    The Language Arts 6-12 Program of the Des Moines Independent Community School District (Iowa) is directed by its mission statement to provide a quality educational program to a diverse community of students where all are expected to learn. The Language Arts supervisor is responsible for supervising and coordinating all aspects of the middle and…

  13. Method of Controlling Lasing Wavelength(s)

    NASA Technical Reports Server (NTRS)

    Barnes, Norman P. (Inventor); Murray, Keith E. (Inventor); Hutcheson, Ralph L. (Inventor)

    2000-01-01

    A method is provided to control the lasing wavelength of a laser material without changing or adjusting the mechanical components of a laser device, The rate at which the laser material is pumped with the pumping energy is controlled so that lasing occurs at one or more lasing wavelengths based on the rate. The lasing wavelengths are determined by transition lifetimes and/or energy transfer rates.

  14. InAlGaAs/InP light-emitting transistors operating near 1.55 {mu}m

    SciTech Connect

    Huang Yong; Zhang Xuebing; Ryou, Jae-Hyun; Dupuis, Russell D.; Dixon, Forest; Holonyak, Nick Jr.; Feng, Milton

    2008-06-01

    Light-emitting transistors (LETs) operating at around 1.55 {mu}m were investigated using InP/InAlGaAs heterostructures grown by metal organic chemical vapor deposition. By incorporating InGaAs quantum wells (QWs) in the base region of the N-InP/p-InAlGaAs/N-InAlAs heterojunction bipolar transistors, LET structures were achieved with a current gain of 45 and light emission at a wavelength of 1.65 {mu}m. The light output was found to be dependent on the base current. The larger the number of QWs incorporated in the base of the LETs, the larger the light output, with correspondingly reduced current gain. Secondary ion mass spectroscopy shows that the p-type dopant, zinc (Zn), which is commonly used in the growth of InAlGaAs, diffuses into the emitter and the base active QW region, leading to compromised electrical performance and light output intensity. Increasing the Zn doping level in the barrier layers of the QW structure causes the photoluminescence efficiency to decrease rapidly. Consequently, an alternative low-diffusivity dopant, carbon (C), was studied and a LET with a C-doped base was grown and fabricated. The highest light output was demonstrated for the C-doped LETs owing to the improved quality of the active layer.

  15. 21 CFR 516.23 - Timing of requests for MUMS-drug designation.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...-drug designation. A sponsor may request MUMS-drug designation at any time in the drug development... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Timing of requests for MUMS-drug designation. 516.23 Section 516.23 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND...

  16. 21 CFR 516.23 - Timing of requests for MUMS-drug designation.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...-drug designation. A sponsor may request MUMS-drug designation at any time in the drug development... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Timing of requests for MUMS-drug designation. 516.23 Section 516.23 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND...

  17. 21 CFR 516.23 - Timing of requests for MUMS-drug designation.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...-drug designation. A sponsor may request MUMS-drug designation at any time in the drug development... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Timing of requests for MUMS-drug designation. 516.23 Section 516.23 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND...

  18. 21 CFR 516.23 - Timing of requests for MUMS-drug designation.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...-drug designation. A sponsor may request MUMS-drug designation at any time in the drug development... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Timing of requests for MUMS-drug designation. 516.23 Section 516.23 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND...

  19. 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...

  20. 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...

  1. 21 CFR 516.23 - Timing of requests for MUMS-drug designation.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...-drug designation. A sponsor may request MUMS-drug designation at any time in the drug development... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Timing of requests for MUMS-drug designation. 516.23 Section 516.23 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND...

  2. 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)

  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. A new optical wavelength ratio measurement apparatus: The fringe counting sigmameter

    SciTech Connect

    Juncar, P.; Elandaloussi, H.; Himbert, M.

    1994-12-31

    A new compact and achromatic Michelson-type interferometer with a variable path difference is presented. This {open_quotes}fringe-counting sigmameter{close_quotes} allows to measure optical wavelength ratios between two radiations emitted by stabilized lasers. Maintained in vacuum, this apparatus can determine wavelength/frequency laser radiation from 0,36 {mu}m to 1,5 {mu}m with a relative accuracy of 5.10{sup -9}, with the use of a reference stabilized He-Ne laser.

  6. Transparency of the Atmosphere to Short Horizontal Wavelength Gravity Waves

    DTIC Science & Technology

    2008-12-16

    around the initial horizontal wavelengths and the maxi - mum value is normalized to 1.0 (black rectangles). Then the function y ¼ 1 p arctan zxþ hð Þ þ...Space Res., 35, 2017 –2023, doi:10.1016/ j.asr.2005.04.109. Ern, M., P. Preusse, and C. D. Warner (2006), Some experimental con- straints for spectral

  7. 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.

  8. SPITZER 24 {mu}m SURVEY FOR DUST DISKS AROUND HOT WHITE DWARFS

    SciTech Connect

    Chu, You-Hua; Bilikova, Jana; Gruendl, Robert A.; Su, Kate Y. L.; De Marco, Orsola; Guerrero, Martin A.; Updike, Adria C.; Rauch, Thomas

    2011-09-15

    Two types of dust disks around white dwarfs (WDs) have been reported: small dust disks around cool metal-rich WDs consisting of tidally disrupted asteroids and a large dust disk around the hot central WD of the Helix planetary nebula (PN) possibly produced by collisions among Kuiper-Belt-like objects. To search for more dust disks of the latter type, we have conducted a Spitzer MIPS 24 {mu}m survey of 71 hot WDs or pre-WDs, among which 35 are central stars of PNe (CSPNs). Nine of these evolved stars are detected and their 24 {mu}m flux densities are at least two orders of magnitude higher than their expected photospheric emission. Considering the bias against the detection of distant objects, the 24 {mu}m detection rate for the sample is {approx}>15%. It is striking that seven, or {approx}20%, of the WD and pre-WDs in known PNe exhibit 24 {mu}m excesses, while two, or 5%-6%, of the WDs not in PNe show 24 {mu}m excesses and they have the lowest 24 {mu}m flux densities. We have obtained follow-up Spitzer Infrared Spectrograph spectra for five objects. Four show clear continuum emission at 24 {mu}m, and one is overwhelmed by a bright neighboring star but still shows a hint of continuum emission. In the cases of WD 0950+139 and CSPN K 1-22, a late-type companion is present, making it difficult to determine whether the excess 24 {mu}m emission is associated with the WD or its red companion. High-resolution images in the mid-infrared are needed to establish unambiguously the stars responsible for the 24 {mu}m excesses.

  9. 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}.

  10. Simple wavelength assignment protocol

    NASA Astrophysics Data System (ADS)

    Suryaputra, Stephen; Touch, Joseph D.; Bannister, Joseph A.

    2000-10-01

    IP routers can be coupled with wavelength-selective optical cross- connects to support existing Internet infrastructure in a wavelength division multiplexing (WDM) optical network. Because optical wavelength routing is transparent to IP, packets can bypass traditional forwarding and pass directly through the optical cross-connect, resulting in very high throughput and low delay routing. This approach shares features with label switching, but wavelengths are much more scarce resource than labels. Because optical switches have larger switching times than electronic switches, and wavelength conversions are expensive, wavelength label swapping is not easily done. Wavelength label assignments must consider these limitations to be practical in an optical environment. The performance of an instance of this approach, called Packet over Wavelengths (POW) has been simulated and studied. A new signaling protocol, Simple Wavelength Assignment Protocol (SWAP) is devised to be POW signaling protocol. SWAP takes into account the optical device limitations, and is designed to minimize wavelength conversion, utilize wavelengths with the merging of flows, and reduce the reconfiguration of optical switches. SWAP, to our knowledge, is the first approach to combine signaling and wavelength assignment in an on- line protocol. This paper describes high level SWAP design challenges, decision, and overhead.

  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. 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

  14. 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.

  15. Metal slit array Fresnel lens for wavelength-scale optical coupling to nanophotonic waveguides.

    PubMed

    Jung, Young Jin; Park, Dongwon; Koo, Sukmo; Yu, Sunkyu; Park, Namkyoo

    2009-10-12

    We propose a novel metal slit array Fresnel lens for wavelength-scale optical coupling into a nanophotonic waveguide. Using the plasmonic waveguide structure in Fresnel lens form, a much wider beam acceptance angle and wavelength-scale working distance of the lens was realized compared to a conventional dielectric Fresnel lens. By applying the plasmon waveguide dispersion relation to a phased antenna array model, we also develop and analyze design rules and parameters for the suggested metal slit Fresnel lens. Numerical assessment of the suggested structure shows excellent coupling efficiency (up to 59%) of the 10 mum free-space Gaussian beam to the 0.36 mum Si waveguide within a working distance of a few mum.

  16. 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.

  17. PROBING THE '30 {mu}m' FEATURE: LESSONS FROM EXTREME CARBON STARS

    SciTech Connect

    Messenger, Stephen J.; Speck, Angela; Volk, Kevin E-mail: speckan@missouri.edu

    2013-02-20

    Some carbon-rich evolved stars exhibit a very prominent spectral feature at {approx}{sup 3}0 {mu}m''. The C-rich nature of these objects suggests that the carrier is a sulfide, carbide, or other substance apt to form in a reducing environment. However, the carrier of this spectral feature remains disputed, with magnesium sulfide (MgS) as the most favored candidate. In order to investigate the carrier of the {sup 3}0 {mu}m'' feature further, we have taken a dual approach, studying both laboratory and observational data. In order to obtain a homogeneous sample, we studied the {sup 3}0 {mu}m'' feature observed in the spectra of galactic extreme carbon stars that exhibit the 11 {mu}m SiC absorption feature. Thus, we avoid potential differences in the target objects that could contribute to the observed differences in the shape, position, and strength of the {sup 3}0 {mu}m'' feature. In addition, we analyzed the shape and position of the {sup 3}0 {mu}m'' features for a range of sulfide minerals for which laboratory data exist. Our study of observed astronomical features shows a range of shapes and positions for the {sup 3}0 {mu}m'' feature despite similarities in the source objects. The nature of our sample argues against grain processing or temperature differences due to hardening of the stellar radiation field with evolution. While there are very few correlations between spectral parameters for our sample, the peak positions of the {approx}11 {mu}m absorption and 30 {mu}m emission features do correlate, and these peak positions correlate with the modeled optical depth. These correlations suggest that the carriers of the observable spectral features are closely related to one another and to the density/pressure in the dust formation zone. Furthermore, we suggest that the blue-broadening of the 11 {mu}m feature cannot be attributed to SiS{sub 2} based on existing laboratory spectra, but further lab work is needed to investigate the effect of increasing oxidation.

  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. 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

  20. 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

  1. Improved executive functions in 6-12-year-old children following cognitively engaging tennis lessons.

    PubMed

    Ishihara, Toru; Sugasawa, Shigemi; Matsuda, Yusuke; Mizuno, Masao

    2016-11-16

    The aim of this cross-sectional study was to evaluate the relationships between cognitively engaging exercise (i.e., game-based and coordination exercises), executive functions (i.e., inhibitory control and working memory), and physical fitness. Forty junior tennis players (6-12 years old), who regularly participated in tennis lessons (2.55 years, SD = 1.61) prior to the study, were investigated. All participants completed evaluations of executive functions (inhibitory control and working memory) at rest. The duration of each lessons' instructional activities, including coordination training, game-based exercise, rallying, and non-physical activity (explanations and breaks), was recorded. Physical fitness was evaluated using the Tennis Field Test. A longer duration of game-based exercise was positively correlated with inhibitory control and physical fitness. Coordination training was associated with improved working memory. Non-physical activity was inversely correlated with inhibitory control, working memory, and physical fitness. The results suggest that game-based tennis lessons have beneficial effects on inhibitory control and physical fitness levels, and a longer duration of coordination training is associated with better working memory. The present study indicates that shortened non-physical activity time within a sports setting is associated with the development of executive functions and physical fitness.

  2. Short wavelength FELS

    SciTech Connect

    Sheffield, R.L.

    1991-01-01

    The generation of coherent ultraviolet and shorter wavelength light is presently limited to synchrotron sources. The recent progress in the development of brighter electron beams enables the use of much lower energy electron rf linacs to reach short-wavelengths than previously considered possible. This paper will summarize the present results obtained with synchrotron sources, review proposed short- wavelength FEL designs and then present a new design which is capable of over an order of magnitude higher power to the extreme ultraviolet. 17 refs., 10 figs.

  3. Laser-plasma interaction experiments at laser wavelengths of 1. 064. mu. m, 0. 532. mu. m, and 0. 355. mu. m

    SciTech Connect

    Campbell, E.M.; Mead, W.C.; Turner, R.E.

    1982-01-01

    The effect of laser wavelength on laser-plasma coupling is one of the critical issues facing the laser driven inertial confinement community. The advantages of using lasers with output wavelength less than 1 ..mu..m, such as enhanced absorption and hydrodynamic efficiency, reduction in parametric instabilities and corresponding suprathermal electron generation, have long been predicted theoretically.

  4. 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.

  5. A passively mode-locked fiber laser at 1.54 mum with a fundamental repetition frequency reaching 2 GHz.

    PubMed

    McFerran, J J; Nenadovic, L; Swann, W C; Schlager, J B; Newbury, N R

    2007-10-01

    We demonstrate a fundamentally mode-locked fiber laser with a repetition frequency in excess of 2 GHz at a central wavelength of 1.535 mum. Co-doped ytterbium-erbium fiber provides the gain medium for the laser, affording high gain per unit length, while a semiconductor saturable absorber mirror (SAM) provides the pulse shaping mechanism in a standing wave cavity. Results are shown confirming cw mode-locking for 1 GHz and 2 GHz repetition frequency systems. The response of the frequency comb output to pump power variations is shown to follow a single pole response. The timing jitter of a 540MHz repetition-rate laser has been suppressed to below 100 fs through phase-lead compensated feedback to the pump power. Alternatively, a single comb line of a 850MHz repetition-rate laser has been phase-locked to a narrow linewidth cw laser with an in-loop phase jitter of 0.06 rad(2). The laser design is compatible with low-noise oscillator applications.

  6. 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.

  7. 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.

  8. 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.

  9. 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

  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. 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…

  12. 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...

  13. SPITZER 70 AND 160 {mu}m OBSERVATIONS OF THE COSMOS FIELD

    SciTech Connect

    Frayer, D. T.; Huynh, M. T.; Bhattacharya, B.; Fadda, D.; Helou, G.; Sanders, D. B.; Le Floc'h, E.; Ilbert, O.; Kartaltepe, J. S.; Lee, N.; Surace, J. A.; Capak, P.; Murphy, E.; Aussel, H.; Salvato, M.; Scoville, N. Z.; Fu, H.; Afonso-Luis, A.; Sargent, M. T.

    2009-11-15

    We present Spitzer 70 and 160 {mu}m observations of the COSMOS Spitzer survey (S-COSMOS). The data processing techniques are discussed for the publicly released products consisting of images and source catalogs. We present accurate 70 and 160 {mu}m source counts of the COSMOS field and find reasonable agreement with measurements in other fields and with model predictions. The previously reported counts for GOODS-North and the extragalactic First Look Survey are updated with the latest calibration, and counts are measured based on the large area SWIRE survey to constrain the bright source counts. We measure an extragalactic confusion noise level of {sigma} {sub c} = 9.4 {+-} 3.3 mJy (q = 5) for the MIPS 160 {mu}m band based on the deep S-COSMOS data and report an updated confusion noise level of {sigma} {sub c} = 0.35 {+-} 0.15 mJy (q = 5) for the MIPS 70 {mu}m band.

  14. 21 CFR 516.30 - Annual reports for a MUMS-designated drug.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... Drug Development that includes the following information: (a) A short account of the progress of drug... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Annual reports for a MUMS-designated drug. 516.30 Section 516.30 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN...

  15. 21 CFR 516.25 - Refusal to grant MUMS-drug designation.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... successful drug development in a timely manner, and (iii) Any other information required under § 516.20. (b... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Refusal to grant MUMS-drug designation. 516.25 Section 516.25 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN...

  16. 21 CFR 516.25 - Refusal to grant MUMS-drug designation.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... successful drug development in a timely manner, and (iii) Any other information required under § 516.20. (b... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Refusal to grant MUMS-drug designation. 516.25 Section 516.25 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN...

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

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... with the drug development plan submitted to the agency under § 516.20 and (2) Compliance with all... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Termination of MUMS-drug designation. 516.29 Section 516.29 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN...

  18. 21 CFR 516.25 - Refusal to grant MUMS-drug designation.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... successful drug development in a timely manner, and (iii) Any other information required under § 516.20. (b... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Refusal to grant MUMS-drug designation. 516.25 Section 516.25 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN...

  19. 21 CFR 516.30 - Annual reports for a MUMS-designated drug.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... Drug Development that includes the following information: (a) A short account of the progress of drug... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Annual reports for a MUMS-designated drug. 516.30 Section 516.30 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN...

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

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... with the drug development plan submitted to the agency under § 516.20 and (2) Compliance with all... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Termination of MUMS-drug designation. 516.29 Section 516.29 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN...

  1. 21 CFR 516.25 - Refusal to grant MUMS-drug designation.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... successful drug development in a timely manner, and (iii) Any other information required under § 516.20. (b... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Refusal to grant MUMS-drug designation. 516.25 Section 516.25 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN...

  2. 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...

  3. 21 CFR 516.29 - Termination of MUMS-drug designation.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... with the drug development plan submitted to the agency under § 516.20 and (2) Compliance with all... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Termination of MUMS-drug designation. 516.29 Section 516.29 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN...

  4. 21 CFR 516.25 - Refusal to grant MUMS-drug designation.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... successful drug development in a timely manner, and (iii) Any other information required under § 516.20. (b... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Refusal to grant MUMS-drug designation. 516.25 Section 516.25 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN...

  5. 21 CFR 516.30 - Annual reports for a MUMS-designated drug.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... Drug Development that includes the following information: (a) A short account of the progress of drug... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Annual reports for a MUMS-designated drug. 516.30 Section 516.30 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN...

  6. BCL6, MUM1 AND CD10 EXPRESSION IN MANTLE CELL LYMPHOMA

    PubMed Central

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

    2009-01-01

    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 (GC) 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. 32% 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. PMID:19826251

  7. "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…

  8. 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…

  9. 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.

  10. QUANTIFYING NON-STAR-FORMATION-ASSOCIATED 8 {mu}m DUST EMISSION IN NGC 628

    SciTech Connect

    Crocker, Alison F.; Calzetti, Daniela; Thilker, David A.; Aniano, Gonzalo; Draine, Bruce T.; Hunt, Leslie K.; Kennicutt, Robert C.; Sandstrom, Karin; Smith, J. D. T.

    2013-01-10

    Combining H{alpha} and IRAC images of the nearby spiral galaxy NGC 628, we find that between 30% and 43% of its 8 {mu}m dust emission is not related to recent star formation. Contributions from dust heated by young stars are separated by identifying H II regions in the H{alpha} map and using these areas as a mask to determine the 8 {mu}m dust emission that must be due to heating by older stars. Corrections are made for sub-detection-threshold H II regions, photons escaping from H II regions, and for young stars not directly associated with H II regions (i.e., 10-100 Myr old stars). A simple model confirms that this amount of 8 {mu}m emission can be expected given dust and PAH absorption cross sections, a realistic star formation history, and the observed optical extinction values. A Fourier power spectrum analysis indicates that the 8 {mu}m dust emission is more diffuse than the H{alpha} emission (and similar to observed H I), supporting our analysis that much of the 8 {mu}m-emitting dust is heated by older stars. The 8 {mu}m dust-to-H{alpha} emission ratio declines with galactocentric radius both within and outside of H II regions, probably due to a radial increase in disk transparency. In the course of this work, we have also found that intrinsic diffuse H{alpha} fractions may be lower than previously thought in galaxies, if the differential extinction between H II regions and diffuse regions is taken into account.

  11. Miniaturized optical wavelength sensors

    NASA Astrophysics Data System (ADS)

    Kung, Helen Ling-Ning

    Recently semiconductor processing technology has been applied to the miniaturization of optical wavelength sensors. Compact sensors enable new applications such as integrated diode-laser wavelength monitors and frequency lockers, portable chemical and biological detection, and portable and adaptive hyperspectral imaging arrays. Small sensing systems have trade-offs between resolution, operating range, throughput, multiplexing and complexity. We have developed a new wavelength sensing architecture that balances these parameters for applications involving hyperspectral imaging spectrometer arrays. In this thesis we discuss and demonstrate two new wavelength-sensing architectures whose single-pixel designs can easily be extended into spectrometer arrays. The first class of devices is based on sampling a standing wave. These devices are based on measuring the wavelength-dependent period of optical standing waves formed by the interference of forward and reflected waves at a mirror. We fabricated two different devices based on this principle. The first device is a wavelength monitor, which measures the wavelength and power of a monochromatic source. The second device is a spectrometer that can also act as a selective spectral coherence sensor. The spectrometer contains a large displacement piston-motion MEMS mirror and a thin GaAs photodiode flip-chip bonded to a quartz substrate. The performance of this spectrometer is similar to that of a Michelson in resolution, operating range, throughput and multiplexing but with the added advantages of fewer components and one-dimensional architecture. The second class of devices is based on the Talbot self-imaging effect. The Talbot effect occurs when a periodic object is illuminated with a spatially coherent wave. Periodically spaced self-images are formed behind the object. The spacing of the self-images is proportional to wavelength of the incident light. We discuss and demonstrate how this effect can be used for spectroscopy

  12. Long wavelength infrared detector

    NASA Technical Reports Server (NTRS)

    Vasquez, Richard P. (Inventor)

    1993-01-01

    Long wavelength infrared detection is achieved by a detector made with layers of quantum well material bounded on each side by barrier material to form paired quantum wells, each quantum well having a single energy level. The width and depth of the paired quantum wells, and the spacing therebetween, are selected to split the single energy level with an upper energy level near the top of the energy wells. The spacing is selected for splitting the single energy level into two energy levels with a difference between levels sufficiently small for detection of infrared radiation of a desired wavelength.

  13. 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.

  14. 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}.

  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. 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}.

  17. 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.

  18. Line-by-line radiative excitation model for the non-equilibrium atmosphere: Application to CO[sub 2] 15-[mu]m emission

    SciTech Connect

    Wintersteiner, P.P. ); Picard, R.H.; Sharma, R.D.; Winick, J.R. )

    1992-11-20

    We describe a new line-by-line (LBL) algorithm for radiative excitation in infrared bands in a non-local thermodynamic equilibrium (non-LTE) planetary atmosphere. Specifically, we present a predictive model for the terrestrial CO[sub 2] 15[mu]m emission that incorporates this generic algorithm, and validate the model by comparing its results with emission spectra obtained in a limb-scanning rocket experiment. The unique features of the reactive-excitation algorithm are discussed in this paper. These features contribute to accurate radiative transfer results and reliable atmospheric cooling rates. For altitudes above 40 km, we present results of model calculations of CO[sub 2]([nu][sub 2]) vibrational temperatures, 15-[mu]m limb spectral radiances, and cooling rates, for the main band and for weaker hot and isotopic bands. We calculate the excitation and deexcitation rates due to different processes. We compare the predicted limb radiance with earthlimb spectral scans obtained in the SPIRE rocket experiment over Poker Flat, Alaska, and get excellent agreement as a function of both wavelength and tangent height. This constitutes the first validation of a long-wavelength CO[sub 2] non-LTE emission model using an actual atmospheric data set and verifies the existence of certain aeronomic features that have only been predicted by models and constrains the previously unknown value of the very important rate constant for deactivation of the CO[sub 2] bending mode by atomic oxygen to the range of 5-6 [times] 10[sup [minus]12] cm[sup 3]/(mol s) at mesospheric and lower thermospheric temperatures. We discuss the significance of this large value for terrestrial and Venusian thermospheres and the convergence rate of the iterative scheme, the model's sensitivity to the background atmosphere, the importance of the lower boundary surface contribution, and the effects of the choice of the layer thickness and the neglect of line overlap. 86 refs., 20 figs., 5 tabs.

  19. 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.

  20. Triple wavelength monitor PDIC

    NASA Astrophysics Data System (ADS)

    Park, Deukhee; Ha, Chang-woo; Shin, Sang-cheol; Kwon, Kyoung-soo; Ko, Joo-yul; Kang, Shin-jae

    2006-08-01

    Recently the demand for high-capacity optical storage systems compatible with CD, DVD, and Blue is growing. We designed the Vertical NIP photodiode with a diameter of 700um and the trans-impedance circuits by using 0.6um BiCMOS process. The measured sensitivity of the photodiode is 0.25, 0.42, and 0.48A/W for 405, 650, and 780nm wavelength lights, respectively. The capacitance of the PD is 4.5pF. Monitor PDIC for detecting triple wavelength lights is presented in this paper. The complete monitor PDIC with the NIP photodiode of 700um in diameter occupies 1900um*1200um. -3dB bandwidth is 110MHz and the temperature drift of output voltage is 3.2%.

  1. 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.

  2. Determination of arm fat area and arm muscle area norms in children 6-12 years of age in Bursa.

    PubMed

    Günay, U; Sapan, N; Salih, C; Doğruyol, H

    1990-01-01

    Since arm fat area and arm muscle area measurements are said to assess the calorie and protein reserves in the body more accurately than triceps skinfold thickness measurements, we decided to use this system on 1497 girls and 1651 boys who were pupils in elementary schools in Bursa. From the data obtained, percentile norms for the children aged between 6-12 were calculated and percentile curves were drawn. The data that we collected can be used in future nutritional surveys.

  3. Millimeter wavelength thermographic scanner.

    PubMed

    Cacak, R K; Winans, D E; Edrich, J; Hendee, W R

    1981-01-01

    Two new types of thermographic instruments sensitive to millimeter-wave electromagnetic radiation have been designed, constructed, and tested. These instruments utilize wavelengths that are three orders of magnitude longer and much more penetrating than those used in conventional infrared thermography. The instruments are capable of detecting apparent thermal variations as small as a fraction of a degree existing at tissue depths of several millimeters below the skin. By comparison, conventional IR thermographic units are limited to sampling radiation emitted only from the surface. The millimeter wave thermographic units are designed to contribute to the clinical detection of breast abnormalities with the specific aim of accurately and noninvasively detecting breast cancer.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. Evaluation of optical coherence quantitation of analytes in turbid media by use of two wavelengths

    SciTech Connect

    Sathyam, U.S.; Colston, B.W. Jr.; Da Silva, L.B.; Everett, M.J.

    1999-04-01

    We introduce a novel method for determining analyte concentration as a function of depth in a highly scattering media by use of a dual-wavelength optical coherence tomography system. We account for the effect of scattering on the measured attenuation by using a second wavelength that is not absorbed by the sample. We assess the applicability of this technique by measuring the concentration of water in an Intralipid phantom, using a probe wavelength of 1.53 {mu}m and a reference wavelength of 1.31 {mu}m. The results of our study show a strong correlation between the measured absorption and the water content of the sample. The accuracy of the technique, however, was limited by the dominance of scattering over absorption in the turbid media. Thus, although the effects of scattering were minimized, significant errors remained in the calculated absorption values. More-accurate results could be obtained with the use of more powerful superluminescent diodes and a choice of wavelengths at which absorption effects are more significant relative to scattering. {copyright} 1999 Optical Society of America

  11. 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.

  12. 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.

  13. 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.

  14. Microlens performance limits in sub-2mum pixel CMOS image sensors.

    PubMed

    Huo, Yijie; Fesenmaier, Christian C; Catrysse, Peter B

    2010-03-15

    CMOS image sensors with smaller pixels are expected to enable digital imaging systems with better resolution. When pixel size scales below 2 mum, however, diffraction affects the optical performance of the pixel and its microlens, in particular. We present a first-principles electromagnetic analysis of microlens behavior during the lateral scaling of CMOS image sensor pixels. We establish for a three-metal-layer pixel that diffraction prevents the microlens from acting as a focusing element when pixels become smaller than 1.4 microm. This severely degrades performance for on and off-axis pixels in red, green and blue color channels. We predict that one-metal-layer or backside-illuminated pixels are required to extend the functionality of microlenses beyond the 1.4 microm pixel node.

  15. THE CONNECTION BETWEEN 3.3 {mu}m POLYCYCLIC AROMATIC HYDROCARBON EMISSION AND ACTIVE GALACTIC NUCLEUS ACTIVITY

    SciTech Connect

    Woo, Jong-Hak; Park, Dawoo; Kim, Ji Hoon; Imanishi, Masatoshi

    2012-02-15

    We investigate the connection between starburst and active galactic nucleus (AGN) activity by comparing 3.3 {mu}m polycyclic aromatic hydrocarbon (PAH) emission with AGN properties. Utilizing the slitless spectroscopic capability of the AKARI space telescope, we observe a moderate-luminosity Type I AGN at z {approx} 0.4 to measure global starburst activity. The 3.3 {mu}m PAH emissions are detected for 7 out of 26 target galaxies. We find no strong correlation between the 3.3 {mu}m PAH emission and AGN luminosity in the limited range of the observed AGN luminosity, suggesting that global star formation may not be closely related to AGN activity. Combining our measurements with previous 3.3 {mu}m measurements of low-redshift Type I AGNs in the literature, we investigate the connection between nuclear starburst and AGN activity. In contrast to global star formation, the 3.3 {mu}m PAH luminosity measured from the central part of galaxies correlates with AGN luminosity, implying that starburst activity and AGN activity are directly connected in the nuclear region.

  16. Research with high-power short-wavelength lasers

    SciTech Connect

    Holzrichter, J.F.; Campbell, E.M.; Lindl, J.D.; Storm, E.

    1985-03-05

    Three important high-temperature, high-density experiments were conducted recently using the 10-TW, short-wavelength Novette laser system at the Lawrence Livermore National Laboratory. These experiments demonstrated successful solutions to problems that arose during previous experiments with long wavelength lasers (lambda greater than or equal to 1..mu..m) in which inertial confinement fusion (ICF), x-ray laser, and other high-temperature physics concepts were being tested. The demonstrations were: (1) large-scale plasmas (typical dimensions of up to 1000 laser wavelengths) were produced in which potentially deleterious laser-plasma instabilities were collisionally damped. (2) Deuterium-tritium fuel was imploded to a density of 20 g/cm/sup 3/ and a pressure of 10/sup 10/ atm. (3) A 700-fold amplification of soft x rays by stimulated emission at 206 and 209 A (62 eV) from Se/sup +24/ ions was observed in a laser-generated plasma. Isoelectronic scaling to 155 A (87 eV) in Y/sup +29/ was also demonstrated.

  17. 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.

  18. The growth and delivery of mesenchymal and limbal stem cells using copolymer polyamide 6/12 nanofiber scaffolds.

    PubMed

    Holan, Vladimir; Javorkova, Eliska; Trosan, Peter

    2013-01-01

    The injured or otherwise damaged cornea is healed by limbal stem cells (LSC). If the limbus where LSC reside is also damaged or nonfunctional, the cornea cannot heal properly and this defect leads to impaired vision that can result in blindness. The only way to treat total LSC deficiency is by transplantation of limbal tissue or a transfer of LSC. Recently, mesenchymal stem cells (MSC) have been shown as another promising source of stem cells for corneal healing and regeneration. Here, we describe a protocol for the use of polyamide 6/12 nanofiber scaffolds for the growth of MSC and LSC, and for their transfer onto a mechanically damaged ocular surface in the experimental mouse model.

  19. DETECTIONS OF WATER ICE, HYDROCARBONS, AND 3.3 {mu}m PAH IN z {approx} 2 ULIRGs

    SciTech Connect

    Sajina, Anna; Spoon, Henrik; Yan Lin; Imanishi, Masatoshi; Fadda, Dario; Elitzur, Moshe

    2009-09-20

    We present the first detections of the 3 {mu}m water ice and 3.4 {mu}m amorphous hydrocarbon (HAC) absorption features in z {approx} 2 ULIRGs. These are based on deep rest-frame 2-8 {mu}m Spitzer Infrared Spectrograph spectra of 11 sources selected for their appreciable silicate absorption. The HAC-to-silicate ratio for our z {approx} 2 sources is typically higher by a factor of 2-5 than that observed in the Milky Way. This HAC 'excess' suggests compact nuclei with steep temperature gradients as opposed to predominantly host obscuration. Beside the above molecular absorption features, we detect the 3.3 {mu}m polycyclic aromatic hydrocarbon (PAH) emission feature in one of our sources with three more individual spectra showing evidence for it. Stacking analysis suggests that water ice, hydrocarbons, and PAH are likely present in the bulk of this sample even when not individually detected. The most unexpected result of our study is the lack of clear detections of the 4.67 {mu}m CO gas absorption feature. Only three of the sources show tentative signs of this feature at significantly lower levels than has been observed in local ULIRGs. Overall we find that the closest local analogs to our sources, in terms of 3-4 {mu}m color, HAC-to-silicate and ice-to-silicate ratios, as well as low PAH equivalent widths, are sources dominated by deeply obscured nuclei. Such sources form only a small fraction of ULIRGs locally and are commonly believed to be dominated by buried active galactic nuclei (AGNs). Our sample suggests that, in an absolute number, such buried AGNs are at least an order of magnitude more common at z {approx} 2 than today. The presence of PAH suggests that significant levels of star formation are present even if the obscured AGNs typically dominate the power budget.

  20. THE 3.3 {mu}m POLYCYCLIC AROMATIC HYDROCARBON EMISSION AS A STAR FORMATION RATE INDICATOR

    SciTech Connect

    Kim, Ji Hoon; Im, Myungshin; Jun, Hyunsung David; Lee, Hyung Mok; Lee, Myung Gyoon; Nakagawa, Takao; Matsuhara, Hideo; Wada, Takehiko; Takagi, Toshinobu; Oyabu, Shinki; Yamada, Rika; Inami, Hanae; Armus, Lee; Ohyama, Youichi; Helou, George; Shi, Yong E-mail: mim@astro.snu.ac.kr

    2012-12-01

    Polycyclic aromatic hydrocarbon (PAH) emission features dominate the mid-infrared spectra of star-forming galaxies and can be useful to calibrate star formation rates (SFRs) and diagnose ionized states of grains. However, the PAH 3.3 {mu}m feature has not been studied as much as other PAH features since it is weaker than others and resides outside of Spitzer capability. In order to detect and calibrate the 3.3 {mu}m PAH emission and investigate its potential as an SFR indicator, we carried out an AKARI mission program, AKARI mJy Unbiased Survey of Extragalactic Sources (AMUSES), and compared its sample with various literature samples. We obtained 2-5 {mu}m low-resolution spectra of 20 flux-limited galaxies with mixed spectral energy distribution classes, which yielded the detection of the 3.3 {mu}m PAH emission from 3 out of 20 galaxies. For the combined sample of AMUSES and literature samples, the 3.3 {mu}m PAH luminosities correlate with the infrared luminosities of star-forming galaxies, albeit with a large scatter (1.5 dex). The correlation appears to break down at the domain of ultraluminous infrared galaxies (ULIRGs), and the power of the 3.3 {mu}m PAH luminosity as a proxy for the infrared luminosity is hampered at log[L {sub PAH3.3} erg{sup -1} s{sup -1}] > {approx}42.0. Possible origins for this deviation in the correlation are discussed, including contributions from active galactic nuclei and strongly obscured young stellar objects, and the destruction of PAH molecules in ULIRGs.

  1. 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.

  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.

  3. 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.

  4. 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.

  5. 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 }.

  6. Multiple-wavelength tunable laser

    NASA Technical Reports Server (NTRS)

    Barnes, Norman P. (Inventor); Walsh, Brian M. (Inventor); Reichle, Donald J. (Inventor)

    2010-01-01

    A tunable laser includes dispersion optics for separating generated laser pulses into first and second wavelength pulses directed along first and second optical paths. First and second reflective mirrors are disposed in the first and second optical paths, respectively. The laser's output mirror is partially reflective and partially transmissive with respect to the first wavelength and the second wavelength in accordance with provided criteria. A first resonator length is defined between the output mirror and the first mirror, while a second resonator length is defined between the output mirror and the second mirror. The second resonator length is a function of the first resonator length.

  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. 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.

  9. 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.

  10. 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.

  11. Assessment of food habits in children aged 6-12 years and the risk of caries.

    PubMed

    Doichinova, Liliya; Bakardjiev, Peter; Peneva, Milena

    2015-01-02

    Food is necessary for the proper growth and development of children. The excessive intake of low-molecular carbohydrates constitutes a serious health issue, which has an unfavourable impact on the dental health status. The aim of this study was to assess the food habits in healthy children aged 6-12 years and the effect on their oral risk profile. The study included 100 children. The assessment of their nutrition was done with the help of a seven-day reproduction of the food intake and a survey used to determine their underlying food habits and preferences. The results revealed unbalanced nutrition of the children and increased intake of simple sugar, which will increase the risk of development of dental caries. The observed high levels of DMFT (number of decayed, missing and filled teeth) in 54% of the children is a logical result of the frequent intake of sugary foods and beverages for a long period of time, as this will increase the acid production by microorganisms in dental plaque, which is one of the leading etiologic factors for the development of caries. It is necessary for dentists to administer control over the carbohydrate intake and the food habits of children, as well as to encourage non-cariogenic diet in order to keep their good oral health.

  12. Study of ablation by laser irradiation of plane targets at wavelengths 1. 05, 0. 53, and 0. 35. mu. m

    SciTech Connect

    Key, M.H.; Toner, W.T.; Goldsack, T.J.; Kilkenny, J.D.; Veats, S.A.; Cunningham, P.F.; Lewis, C.L.S.

    1983-07-01

    Ablation by laser irradiation at wavelengths lambda = 1.05, 0.53, and 0.35 ..mu..m has been studied from analysis of time-resolved x-ray spectra of layered targets and of ion emission. Irradiance was varied in the range 2 x 10/sup 13/ to 2 x 10/sup 15/ W cm/sup -2/ with constant laser power and variable focal spot size. Deductions include the effect of lateral energy transport from small focal spots and ablation rates and ablation pressures obtained both in the limit of negligible transport and when lateral transport is significant. Advantages of short wavelengths for ablatively driven implosions are quantified.

  13. Carbon dioxide sequestration monitoring and verification via laser based detection system in the 2 mum band

    NASA Astrophysics Data System (ADS)

    Humphries, Seth David

    Carbon Dioxide (CO2) is a known contributor to the green house gas effect. Emissions of CO2 are rising as the global demand for inexpensive energy is placated through the consumption and combustion of fossil fuels. Carbon capture and sequestration (CCS) may provide a method to prevent CO2 from being exhausted to the atmosphere. The carbon may be captured after fossil fuel combustion in a power plant and then stored in a long term facility such as a deep geologic feature. The ability to verify the integrity of carbon storage at a location is key to the success of all CCS projects. A laser-based instrument has been built and tested at Montana State University (MSU) to measure CO2 concentrations above a carbon storage location. The CO2 Detection by Differential Absorption (CODDA) Instrument uses a temperature-tunable distributed feedback (DFB) laser diode that is capable of accessing a spectral region, 2.0027 to 2.0042 mum, that contains three CO2 absorption lines and a water vapor absorption line. This instrument laser is aimed over an open-air, two-way path of about 100 m, allowing measurements of CO2 concentrations to be made directly above a carbon dioxide release test site. The performance of the instrument for carbon sequestration site monitoring is studied using a newly developed CO2 controlled release facility. The field and CO2 releases are managed by the Zero Emissions Research Technology (ZERT) group at MSU. Two test injections were carried out through vertical wells simulating seepage up well paths. Three test injections were done as CO2 escaped up through a slotted horizontal pipe simulating seepage up through geologic fault zones. The results from these 5 separate controlled release experiments over the course of three summers show that the CODDA Instrument is clearly capable of verifying the integrity of full-scale CO2 storage operations.

  14. SPITZER/INFRARED SPECTROGRAPH INVESTIGATION OF MIPSGAL 24 {mu}m COMPACT BUBBLES

    SciTech Connect

    Flagey, N.; Noriega-Crespo, A.; Carey, S. J.; Billot, N.

    2011-11-01

    The MIPSGAL 24 {mu}m Galactic Plane Survey has revealed more than 400 compact-extended objects. Less than 15% of these MIPSGAL bubbles (MBs) are known and identified as evolved stars. We present Spitzer observations of four MBs obtained with the InfraRed Spectrograph to determine the origin of the mid-IR emission. We model the mid-IR gas lines and the dust emission to infer physical conditions within the MBs and consequently their nature. Two MBs show a dust-poor spectrum dominated by highly ionized gas lines of [O IV], [Ne III], [Ne V], [S III], and [S IV]. We identify them as planetary nebulae with a density of a few 10{sup 3} cm{sup -3} and a central white dwarf of {approx}>200,000 K. The mid-IR emission of the two other MBs is dominated by a dust continuum and lower-excitation lines. Both of them show a central source in the near-IR (Two Micron All Sky Survey and IRAC) broadband images. The first dust-rich MB matches a Wolf-Rayet star of {approx}60,000 K at 7.5 kpc with dust components of {approx}170 and {approx}1750 K. Its mass is about 10{sup -3} M{sub sun} and its mass loss is about 10{sup -6} M{sub sun} yr{sup -1}. The second dust-rich MB has recently been suggested as a Be/B[e]/luminous blue variable candidate. The gas lines of [Fe II] as well as hot continuum components ({approx}300 and {approx}1250 K) arise from the inside of the MB while its outer shell emits a colder dust component ({approx}75 K). The distance to the MB remains highly uncertain. Its mass is about 10{sup -3} M{sub sun} and its mass loss is about 10{sup -5} M{sub sun} yr{sup -1}.

  15. Interaction of endokinin A/B and (Mpa(6))-γ2-MSH-6-12 in pain regulation in mice.

    PubMed

    Zhou, Lanxia; Yang, Qing; He, Chunbo; Wei, Chunnan; Yang, Yinliang; Dong, Shouliang

    2015-10-01

    The present study focused on the interactive effects of (Mpa(6))-γ2-MSH-6-12 (Mpa, spinal level) and endokinin A/B (EKA/B, supraspinal level) on pain regulation in mice. EKA/B (30 pmol) only weakened 100 pmol Mpa-induced hyperalgesia at 5 min, but could enhance it during 20-30 min. However, EKA/B (100 pmol) antagonized all dose levels of Mpa significantly at 5 min and blocked them completely at 10 min. EKA/B (3 nmol) co-injected with Mpa presented marked analgesia at 5 min and enduring hyperalgesia within 20-60 min. To investigate the underlying mechanisms between Mpa and EKA/B, SR140333B and SR142801 (NK1 and NK3 receptor antagonists, respectively) were utilized. SR140333B had no influence on Mpa, while SR142801 potentiated it during 20-30 min. Whereas, SR140333B and SR142801 could block the co-administration of Mpa and EKA/B (30 pmol) separately at 5 min and 30 min. These phenomena might attribute to that these two antagonists promoted the antagonism of EKA/B (30 pmol) at the early stage, while antagonized EKA/B preferentially in the latter period. SR140333B weakened the analgesia of EKA/B (3 nmol), but produced no effect on Mpa. However, SR140333B failed to affect the co-injection of Mpa and EKA/B, which implied that EKA/B cooperated with Mpa prior to SR140333B. These results could potentially help to better understand the interaction of NK and MrgC receptors in pain regulation in mice.

  16. Spatial phase stepping wavelength meter

    NASA Astrophysics Data System (ADS)

    Surrel, Yves; García-Márquez, Jorge; Fodor, Jozsua; Juncar, Patrick

    2005-03-01

    A new way of evaluating the ratio between a reference wavelength radiation and an unknown wavelength radiation in a two-beam interferometer is proposed here. The advantage of two-beam interferometry is the sinusoidal fringe signal for which precise phase detection algorithms exist. Modern algorithms can cope with different sources of errors, and correct them. We recall the principle of the Michelson-type lambdameter using temporal interference and we introduce the Young-type lambdameter using spatial interference. The Young-type lambdameter is based on the acquisition of the interference pattern from two point sources (e.g. two ends of monomode fibres projected onto a CCD camera). The measurement of an unknown wavelength can be achieved by comparing with a reference wavelength. Accurate interference phase maps can be calculated using spatial phase shifting. In this way, each small group of contiguous pixels acts as a single interferometer, and the whole set of pixels corresponds to many hundreds or thousands of interferometric measurement system units. The analysis of uncertainties shows that resolutions better than 10-7 can be achieved. An advantage of the fibre wavelength metre described here is the measurement velocity that takes only a few seconds.

  17. 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.

  18. 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.

  19. 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

  20. 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.

  1. 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.

  2. 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.

  3. 1 {mu}m EXCESS SOURCES IN THE UKIDSS. I. THREE T DWARFS IN THE SLOAN DIGITAL SKY SURVEY SOUTHERN EQUATORIAL STRIPE

    SciTech Connect

    Matsuoka, Y.; Murata, K. L.; Fujiwara, M.; Nagayama, T.; Peterson, B. A.; Suenaga, T.; Furusawa, K.; Miyake, N.; Omori, K.; Suzuki, D.; Wada, K.

    2011-08-15

    We report the discovery of two field brown dwarfs, ULAS J0128-0041 and ULAS J0321+0051, and the rediscovery of ULAS J0226+0051 (IfA 0230-Z1), in the Sloan Digital Sky Survey (SDSS) southern equatorial stripe. They are found in the course of our follow-up observation program of 1 {mu}m excess sources in the United Kingdom Infrared Telescope Infrared Deep Sky Survey. The Gemini Multi-Object Spectrographs spectra at red optical wavelengths (6500-10500 A) are presented, which reveal that they are early-T dwarfs. The classification is also supported by their optical to near-infrared colors. It is noted that ULAS J0321+0051 is one of the faintest currently known T dwarfs. The estimated distances to the three objects are 50-110 pc, thus they are among the most distant field T dwarfs known. The dense temporal coverage of the target fields achieved by the SDSS-II Supernova Survey allows us to perform a simple time-series analysis of the dwarfs. We create stacked images of each year from 2002-2007 and find significant proper motions of 150-290 mas yr{sup -1} or transverse velocities of 40-100 km s{sup -1} for ULAS J0128-0041 and ULAS J0226+0051. We also find that there are no detectable, long-term (a-few-year) brightness variations above a few times 0.1 mag for the two brown dwarfs.

  4. 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.

  5. Long wavelength luminescence from gallium-indium-nitrogen-arsenic-antimony on gallium arsenide

    NASA Astrophysics Data System (ADS)

    Gambin, Vincent F.

    GaInNAs grown on GaAs has recently been found to optically emit at wavelengths longer than previously thought possible with material grown epitaxially on GaAs substrates. Dilute-nitride GaInNAs alloys have quickly become an excellent candidate for low cost 1.3--1.55 mum vertical cavity surface emitting lasers (VCSELs) and high power edge emitting lasers in the past few years. Nitride-arsenide alloys were grown by solid source molecular beam epitaxy (MBE) using a N radio frequency (RF) plasma cell. The nitride-arsenide based crystal is grown under metastable conditions with low substrate temperatures and a highly reactive N radical plasma source. However, defects generated during this non-equilibrium growth are a source for non-radiative recombination and diminished photoluminescence (PL). By rapid thermal annealing (RTA) the material after growth, defects are removed from the crystal and the material quality of the GaInNAs films improves significantly. By measuring structural changes that occur during anneal, new insight has been made into the mechanisms which cause the optoelectronic properties to improve. In an effort to further enhance crystal quality, Sb present during GaInNAs growth is thought to act as a surfactant to maintain surface planarity, and phase coherence, resulting in increased PL efficiency. With the addition of Sb, we have observed both a sharp intensity increase in samples with a high In concentration and a bandgap past 1.3 mum. Increasing the In or N content in materials with PL over 1.3 mum normally drops optical intensity; however, using Sb, we can maintain high PL efficiency out to 1.6 mum. Since both In and Sb in GaAs add compressive stress and the solubility of N in GaAs is limited, there is a need for GaNAs tensile strain compensating barriers for applications in multiple quantum well, high-intensity devices. With the development of GaInNAsSb alloys and strain compensated barriers, even longer wavelengths are possible on GaAs, greatly

  6. Dual-wavelength phase-shifting digital holography selectively extracting wavelength information from wavelength-multiplexed holograms.

    PubMed

    Tahara, Tatsuki; Mori, Ryota; Kikunaga, Shuhei; Arai, Yasuhiko; Takaki, Yasuhiro

    2015-06-15

    Dual-wavelength phase-shifting digital holography that selectively extracts wavelength information from five wavelength-multiplexed holograms is presented. Specific phase shifts for respective wavelengths are introduced to remove the crosstalk components and extract only the object wave at the desired wavelength from the holograms. Object waves in multiple wavelengths are selectively extracted by utilizing 2π ambiguity and the subtraction procedures based on phase-shifting interferometry. Numerical results show the validity of the proposed technique. The proposed technique is also experimentally demonstrated.

  7. 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.

  8. Four-wave mixing parametric oscillation and frequency comb generation at visible wavelengths in a silica microbubble resonator

    NASA Astrophysics Data System (ADS)

    Yang, Yong; Jiang, Xuefeng; Kasumie, Sho; Zhao, Guangming; Xu, Linhua; Ward, Jonathan M.; Yang, Lan; Chormaic, Síle Nic

    2016-11-01

    Frequency comb generation in microresonators at visible wavelengths has found applications in a variety of areas such as metrology, sensing, and imaging. To achieve Kerr combs based on four-wave mixing in a microresonator, dispersion must be in the anomalous regime. In this work, we demonstrate dispersion engineering in a microbubble resonator (MBR) fabricated by a two-CO$_2$ laser beam technique. By decreasing the wall thickness of the MBR down to 1.4 $\\mu$m, the zero dispersion wavelength shifts to values shorter than 764 nm, making phase matching possible around 765 nm. With the optical \\textit{Q}-factor of the MBR modes being greater than $10^7$, four-wave mixing is observed at 765 nm for a pump power of 3 mW. By increasing the pump power, parametric oscillation is achieved, and a frequency comb with 14 comb lines is generated at visible wavelengths.

  9. 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

  10. 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).

  11. 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.

  12. An innovative method for the preparation of mum (Thai fermented sausages) with acceptable technological quality and extended shelf-life.

    PubMed

    Wanangkarn, Amornrat; Liu, Deng-Cheng; Swetwiwathana, Adisorn; Tan, Fa-Jui

    2012-11-15

    Freshly-manufactured mum sausages were assigned to two processing methods (process I: stored at ∼30 °C for 14 days; process II: stored at ∼30 °C for three days, vacuum-packaged, and stored at 4 °C until day 28). Physicochemical, microbial, textural, and sensory properties of samples were analysed. The results showed that dehydration was more intense in process I samples, and resulted in lower moisture content and water activity. Significant decreases in pH values, and increases in lactic acid were observed in both samples by day 3. The total microflora and lactic acid bacteria counts increased rapidly during the fermentation and then decreased while the Enterobacteriaceae counts decreased steadily. Too much dehydration resulted in tough textures and unacceptable sensory qualities for process I samples. In conclusion, after three days of fermentation, with vacuum-packaging, ripening and storage at 4 °C up to 28 days, it is possible to produce mum sausages with better qualities and an extended shelf life.

  13. 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.

  14. 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

  15. 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.

  16. 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.

  17. 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.

  18. Flare stars at radio wavelengths

    NASA Technical Reports Server (NTRS)

    Lang, Kenneth R.

    1990-01-01

    The radio emission from dMe flare stars is discussed using Very Large Array and Arecibo observations as examples. Active flare stars emit weak, unpolarized, quiescent radio radiation that may be always present. Although thermal bremsstrahlung and/or thermal gyroresonance radiation account for the slowly-varying, quiescent radio radiation of solar active regions, these processes cannot account for the long-wavelength quiescent radiation observed from nearby dMe flare stars. It has been attributed to nonthermal gyrosynchrotron radiation, but some as yet unexplained mechanism must be continually producing the energetic electrons. Long duration, narrow-band radiation is also emitted from some nearby dMe stars at 20 cm wavelength. Such radiation may be attributed to coherent plasma radiation or to coherent electron-cyclotron masers. Impulsive stellar flares exhibit rapid variations that require radio sources that are smaller than the star in size, and high brightness temperatures greater than 10(exp 15) K that are also explained by coherent radiation processes. Quasi-periodic temporal fluctuations suggest pulsations during some radio flares. Evidence for frequency structure and positive or negative frequency drifts during radio flares from dMe stars is also presented.

  19. Flare stars at radio wavelengths

    NASA Technical Reports Server (NTRS)

    Lang, Kenneth R.

    1989-01-01

    The radio emission from dMe flare stars is discussed using Very Large Array and Arecibo observations as examples. Active flare stars emit weak, unpolarized, quiescent radio radiation that may be always present. Although thermal bremsstrahlung and/or thermal gyroresonance radiation account for the slowly-varying, quiescent radio radiation of solar active regions, these processes cannot account for the long-wavelength quiescent radiation observed from nearby dMe flare stars. It has been attributed to nonthermal gyrosynchrotron radiation, but some as yet unexplained mechanism must be continually producing the energetic electrons. Long duration, narrow-band radiation is also emitted from some nearby dMe stars at 20 cm wavelength. Such radiation may be attributed to coherent plasma radiation or to coherent electron-cyclotron masers. Impulsive stellar flares exhibit rapid variations that require radio sources that are smaller than the star in size, and high brightness temperatures greater than 10(exp 15) K that are also explained by coherent radiation processes. Quasi-periodic temporal fluctuations suggest pulsations during some radio flares. Evidence for frequency structure and positive or negative frequency drifts during radio flares from dMe stars is also presented.

  20. Evaluation of Visual Pedagogy in Dental Check-ups and Preventive Practices Among 6-12-Year-Old Children with Autism.

    PubMed

    Nilchian, Firoozeh; Shakibaei, Fereshteh; Jarah, Zeinab Taghi

    2017-03-01

    This study was aimed to evaluate the impact of visual pedagogy in dental check-ups and preventive practices among children with autism aged 6-12. In this randomized double-blind clinical trial, the cooperation of 40 children with autism age 6-12. The selected children were equally divided into two groups of case and control (n = 20). The obtained data were analyzed by statistical tests, including Chi square and independent t test. The results of Cochran showed a significant increase in children's cooperation with regard to fluoride therapy in the case group by repeating the visit and training sessions (p ≤ 0.001). The findings of this study demonstrated, visual pedagogy was merely effective in the case of fluoride therapy in the case group.

  1. Synthesis, NMR analysis and X-ray crystal structure of 3-(2-naphthoyl)-6,12-diphenyl-3,9-diazatetraasterane

    NASA Astrophysics Data System (ADS)

    Tan, Hong-bo; Song, Xiu-qing; Yan, Hong; Xin, Hong-xing

    2017-02-01

    Novel 3-(2-naphthoyl)-6,12-diphenyl-3,9-diazatetraasterane (3, Tetraethyl 3-(2-naphthoyl)-6,12-diphenyl-3,9-diazapentacyclo [6.4.0.02,7.04,11.05,10]dodecane-1,5,7,11-tetracarboxylate) was prepared by naphthoylation of 3,9-diazatetraasterane (2). The target compound was isolated and unambiguously confirmed by NMR spectra, high-resolution mass spectrometry, and single-crystal X-ray diffraction analysis. In order to discuss the spatial effects on the NMR of 3 by the naphthoyl group, spectra analysis (1D-NMR and 2D-NMR) of 2 and 3 was conducted in details by the shifts and assignments of signals. Single-crystal X-ray diffraction assists to explain the molecular asymmetry of 3 and elucidates the effects of naphthoyl group on the geometry of the central cage of 3,9-diazatetraasterane.

  2. 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…

  3. 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.

  4. [Nutritional condition and serum protein concentration in children (6-12 years old) of Chacopata Sucre State, Venezuela (December--January, 1997)].

    PubMed

    Vásquez, Solange; García, Andrés Gerardi; Lugo, Raquel Salazar

    2004-01-01

    A biochemical and anthropometrical study of 175 children (6-12 years old) from Chacopata, Sucre State was done (December--January, 1997). The children were evaluated by combined anthropometrical indicators (OMS), clinical, nutritional and biochemical tests. The results showed 81.71% well-nourished children, 4.57% obese children and 13.72% with some degree of undernutrition: 3.43% acute undernourished and 10.29% chronic undernourished. Total seric proteins including fractions: albumin, alfa-1 alfa-2, beta and gamma globulins as well as total globulins and albumin/globulin indexes were at the normal reference range for children (6-12 years old). A significative increase in alfa-1 globulin (0.18+/-0.08 g/dl; 8-9 years old group) and decrease of alfa-2 globulin (0.71+/-0.11 g/dl; 10-12 year old group) was observed. Biochemical results associated with nutritional condition showed normal values, moreover, this biochemical index decreased in the undernourished group. A significant decrease of the seric beta globulin in the undernourished children (0.72+/-0,12 g/dl) with respect to the well-nourished children (0.79+/-0.15) was found. In children (6-12 years old) from Chacopata, compensated chronic undernourishement is prevalent.

  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. 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.

  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. 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.

  9. 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.

  10. Localized (5 {mu}m) probing and detailed mapping of hair with synchrotron powered FT-IR microspectroscopy

    SciTech Connect

    Wetzel, David L. Williams, Gwyn P.

    1998-06-01

    The thickness and high absorptivity of single hairs typically result in the saturation of major infrared bands and their distortion. Single human hairs longitudinally microtomed and mounted on mirror slides were scanned routinely in the past with a 20thinsp{mu}m{times}100thinsp{mu}m aperture that limited spatial resolution for localized probing and detailed mapping. Use of the nondivergent, bright, and low-noise synchrotron source for FT-IR microspectroscopy enables good S/N even at apertures as small as 5{endash}6 {mu}m. Functional group mapping as well as localized probing for extraneous materials illustrates the utility of this powerful probe. {copyright} {ital 1998 American Institute of Physics.}

  11. Observation of nonlinear optical phenomena in air and fused silica using a 100 GW, 1.54 mum source.

    PubMed

    Naudeau, M L; Law, R J; Luk, T S; Nelson, T R; Cameron, S M; Rudd, J V

    2006-06-26

    A 100-GW optical parametric chirped-pulse amplifier system is used to study nonlinear effects in the 1.54 mum regime. When focusing this beam in air, strong third-harmonic generation (THG) is observed, and both the spectra and efficiency are measured. Broadening is observed on only the blue side of the third-harmonic signal and an energy conversion efficiency of 0.2% is achieved. When propagated through a 10-cm block of fused silica, a collimated beam is seen to collapse and form multiple filaments. The measured spectral features span 400-2100 nm. The spectrum is dominated by previously unobserved Stokes emissions and broad emissions in the visible.

  12. 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.

  13. SPITZER IRS SPECTRA OF LUMINOUS 8 {mu}m SOURCES IN THE LARGE MAGELLANIC CLOUD: TESTING COLOR-BASED CLASSIFICATIONS

    SciTech Connect

    Buchanan, Catherine L.; Kastner, Joel H.; Hrivnak, Bruce J.; Sahai, Raghvendra

    2009-12-15

    We present archival Spitzer Infrared Spectrograph (IRS) spectra of 19 luminous 8 {mu}m selected sources in the Large Magellanic Cloud (LMC). The object classes derived from these spectra and from an additional 24 spectra in the literature are compared with classifications based on Two Micron All Sky Survey (2MASS)/MSX (J, H, K, and 8 {mu}m) colors in order to test the 'JHK8' (Kastner et al.) classification scheme. The IRS spectra confirm the classifications of 22 of the 31 sources that can be classified under the JHK8 system. The spectroscopic classification of 12 objects that were unclassifiable in the JHK8 scheme allow us to characterize regions of the color-color diagrams that previously lacked spectroscopic verification, enabling refinements to the JHK8 classification system. The results of these new classifications are consistent with previous results concerning the identification of the most infrared-luminous objects in the LMC. In particular, while the IRS spectra reveal several new examples of asymptotic giant branch (AGB) stars with O-rich envelopes, such objects are still far outnumbered by carbon stars (C-rich AGB stars). We show that Spitzer IRAC/MIPS color-color diagrams provide improved discrimination between red supergiants and oxygen-rich and carbon-rich AGB stars relative to those based on 2MASS/MSX colors. These diagrams will enable the most luminous IR sources in Local Group galaxies to be classified with high confidence based on their Spitzer colors. Such characterizations of stellar populations will continue to be possible during Spitzer's warm mission through the use of IRAC [3.6]-[4.5] and 2MASS colors.

  14. Parametric wavelength conversion in photonic crystal fibers

    NASA Astrophysics Data System (ADS)

    Yang, Sigang; Wu, Zhaohui; Yang, Yi; Chen, Minghua; Xie, Shizhong

    2016-11-01

    Nonlinear wavelength conversion provides flexible solutions for generating wideband tunable radiation in novel wavelength band. Parametric process in photonic crystal fibers (PCFs) has attracted comprehensive interests since it can act as broadband tunable light sources in non-conventional wavelength bands. The current state-of-the-art photonic crystal fibers can provide more freedom for customizing the dispersion and nonlinearity which is critical to the nonlinear process, such as four wave mixing (FWM), compared with the traditional fibers fabricated with doping techniques. Here we demonstrate broadband parametric wavelength conversion in our homemade photonic crystal fibers. The zero dispersion wavelength (ZDW) of PCFs is critical for the requirement of phase matching condition in the parametric four wave mixing process. Firstly a procedure of the theoretical design of PCF with the ZDW at 1060 nm is proposed through our homemade simulation software. A group of PCF samples with gradually variable parameters are fabricated according to the theoretical design. The broadband parametric gain around 1060 nm band is demonstrated pumped with our homemade mode locked fiber laser in the anomalous dispersion region. Also a narrow gain band with very large wavelength detune with the pump wavelength in the normal dispersion region is realized. Wavelength conversion with a span of 194 nm is realized. Furthermore a fiber optical parametric oscillator based on the fabricated PCF is built up. A wavelength tunable range as high as 340 nm is obtained. This report demonstrates a systematic procedure to realize wide band wavelength conversion based on PCFs.

  15. Single-wavelength STED microscope

    NASA Astrophysics Data System (ADS)

    Baer, Stephen C.

    2011-03-01

    The zero-point STED microscope (US Pat. 5,866,911)1 was the first far-field microscope to overcome the diffraction limit, but optimally it requires two expensive synchronized short-pulsed lasers. Replacing the synchronized pulsed lasers with CW lasers had been proposed to reduce costs1, but this seriously reduced resolution compared to a similarly powered pulsed STED microscope. A recent theoretical and experimental study (Nat. Methods 4, 915 (2007))3 argued that CW STED has better resolution than previously believed, but there appear to be flaws in the theory sufficient to raise questions about its reported experimental confirmation. We describe an alternative approach to reducing cost of the STED microscope while preserving resolution. A portion of the beam from a femtosecond pulsed laser of a wavelength able to excite fluorescence by multiphoton absorption, is passed through a long optical fiber to stretch the pulses to reduce their peak power so they can no longer excite but can quench by stimulated emission. The stretched pulses are shaped into a doughnut profile and then recombined with the first beam for interaction with the specimen. With suitable fluorophores, this instrument should be able to match the resolution performance of the pulsed laser STED microscope using separate lasers. Particularly when added to an existing multiphoton microscope, such performance should be achievable at extremely low added cost.

  16. 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.

  17. NEAR-INFRARED AND MILLIMETER-WAVELENGTH OBSERVATIONS OF Mol 160: A MASSIVE YOUNG PROTOSTELLAR CORE

    SciTech Connect

    Wolf-Chase, Grace; Smutko, Michael; Sherman, Reid; Harper, Doyal A.; Medford, Michael

    2012-02-01

    We have discovered two compact sources of shocked H{sub 2} 2.12 {mu}m emission coincident with Mol 160 (IRAS 23385+6053), a massive star-forming core thought to be a precursor to an ultracompact H II region. The 2.12 {mu}m sources lie within 2'' (0.05 pc) of a millimeter-wavelength continuum peak where the column density is {>=}10{sup 24} cm{sup -2}. We estimate that the ratio of molecular hydrogen luminosity to bolometric luminosity is >0.2%, indicating a high ratio of mechanical to radiant luminosity. CS J = 2{yields}1 and HCO{sup +} J = 1{yields}0 observations with the Combined Array for Research in Millimeter-wave Astronomy (CARMA) indicate that the protostellar molecular core has a peculiar velocity of {approx}2 km s{sup -1} with respect to its parent molecular cloud. We also observed 95 GHz CH{sub 3}OH J = 8{yields}7 Class I maser emission from several locations within the core. Comparison with previous observations of 44 GHz CH{sub 3}OH maser emission shows that the maser sources have a high mean ratio of 95 GHz to 44 GHz intensity. Our observations strengthen the case that Mol 160 (IRAS 23385+6053) is a rapidly accreting massive protostellar system in a very early phase of its evolution.

  18. 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.

  19. 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.

  20. Short-wavelength MEMS-tunable VCSELs.

    PubMed

    Cole, Garrett D; Behymer, Elaine; Bond, Tiziana C; Goddard, Lynford L

    2008-09-29

    We present electrically-injected MEMS-tunable vertical-cavity surface-emitting lasers with emission wavelengths below 800 nm. Operation in this wavelength range, near the oxygen A-band from 760-780 nm, is attractive for absorption-based optical gas sensing. These fully-monolithic devices are based on an oxide-aperture AlGaAs epitaxial structure and incorporate a suspended dielectric Bragg mirror for wavelength tuning. By implementing electrostatic actuation, we demonstrate the potential for tuning rates up to 1 MHz, as well as a wide wavelength tuning range of 30 nm (767-737 nm).

  1. DISCOVERY OF A RICH CLUSTER AT z = 1.63 USING THE REST-FRAME 1.6 {mu}m 'STELLAR BUMP SEQUENCE' METHOD

    SciTech Connect

    Muzzin, Adam; Hoekstra, Henk; Wilson, Gillian; Demarco, Ricardo; Nantais, Julie; Lidman, Chris; Yee, H. K. C.; Rettura, Alessandro

    2013-04-10

    We present a new two-color algorithm, the 'Stellar Bump Sequence' (SBS), that is optimized for robustly identifying candidate high-redshift galaxy clusters in combined wide-field optical and mid-infrared (MIR) data. The SBS algorithm is a fusion of the well-tested cluster red-sequence method of Gladders and Yee with the MIR 3.6 {mu}m-4.5 {mu}m cluster detection method developed by Papovich. As with the cluster red-sequence method, the SBS identifies candidate overdensities within 3.6 {mu}m-4.5 {mu}m color slices, which are the equivalent of a rest-frame 1.6 {mu}m stellar bump 'red-sequence'. In addition to employing the MIR colors of galaxies, the SBS algorithm incorporates an optical/MIR (z'-3.6 {mu}m) color cut. This cut effectively eliminates foreground 0.2 mu}m-4.5 {mu}m colors that are similarly red as z > 1.0 galaxies and add noise when searching for high-redshift galaxy overdensities. We demonstrate using the z {approx} 1 GCLASS cluster sample that similar to the red sequence, the stellar bump sequence appears to be a ubiquitous feature of high-redshift clusters, and that within that sample the color of the stellar bump sequence increases monotonically with redshift and provides photometric redshifts accurate to {Delta}z = 0.05. We apply the SBS method in the XMM-LSS SWIRE field and show that it robustly recovers the majority of confirmed optical, MIR, and X-ray-selected clusters at z > 1.0 in that field. Lastly, we present confirmation of SpARCS J022427-032354 at z = 1.63, a new cluster detected with the method and confirmed with 12 high-confidence spectroscopic redshifts obtained using FORS2 on the Very Large Telescope. We conclude with a discussion of future prospects for using the algorithm.

  2. Generation and homodyne detection of continuous-variable entangled optical beams with a large wavelength difference

    SciTech Connect

    Guo Xiaomin; Xie Changde; Li Yongmin

    2011-08-15

    We present a scheme for generating and homodyne detecting of continuous-variable entanglement of bright optical beams with a large wavelength difference by utilizing an optical parametric oscillator (OPO) and an optical parametric amplifier (OPA) simultaneously. Entangled optical beams at 0.8 and 1.5 {mu}m are generated from the OPA; the seed beams injected in the OPA as well as the local oscillators at the two wavelengths needed for homodyne detection are provided by the OPO. The entangler is a ring resonator involving a second-order nonlinear crystal that is pumped from two opposite directions. In one direction the pump power is above the oscillation threshold and the optical nonlinear resonator operates as an OPO. In the other direction the pump power is below the threshold and it operates as a phase-sensitive frequency nondegenerate optical parametric amplifier. Our scheme combines the advantages of both OPO and OPA quantum optical devices and opens another avenue for preparation and homodyne detection of high quality bright entangled light with a large wavelength difference.

  3. 880 {mu}m IMAGING OF A TRANSITIONAL DISK IN UPPER SCORPIUS: HOLDOVER FROM THE ERA OF GIANT PLANET FORMATION?

    SciTech Connect

    Mathews, Geoffrey S.; Williams, Jonathan P.; Menard, Francois

    2012-07-01

    We present 880 {mu}m images of the transition disk around the star [PZ99] J160421.7-213028, a solar mass star in the nearby Upper Scorpius association. With a resolution down to 0.''34, we resolve the inner hole in this disk, and via model fitting to the visibilities and spectral energy distribution we determine both the structure of the outer region and the presence of sparse dust within the cavity. The disk contains {approx}0.1 M{sub Jup} of millimeter-emitting grains, with an inner disk edge of about 70 AU. The inner cavity contains a small amount of dust with a depleted surface density in a region extending from about 20 to 70 AU. Taking into account prior observations indicating little to no stellar accretion, the lack of a binary companion, and the presence of dust near {approx}0.1 AU, we determine that the most likely mechanism for the formation of this inner hole is the presence of one or more giant planets.

  4. 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.

  5. 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.

  6. 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.

  7. 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)

  8. Noise performance of 0.35-(mu)m SOI CMOS devices and micropower preamplifier following 63-MeV, 1-Mrad (Si) proton irradiation

    NASA Technical Reports Server (NTRS)

    Binkley, D. M.; Hopper, C. E.; Cressler, J. D.; Mojarradi, M. M.; Blalock, B. J.

    2004-01-01

    This paper presents measured noise for 0.35(mu)m, silicon-on-insulator devices and a micropower preamplifier following 63-MeV, 1-Mrad (Si) proton irradiation. Flicker noise voltage, important for gyros having low frequency output, increases less than 32% after irradiation.

  9. Expression IRF/MUM1>25% Predictor to Three-year Survival of Diffuse Large B Cell Lymphoma in the Immunochemotherapy Era

    PubMed Central

    Sofo-Hafizovic, Alma; Chikha, Adisa; Gojak, Refet; Hadzimesic, Emina Suljovic

    2016-01-01

    Introduction: Non Hodgkin lymphoma-Diffuse large B cell lymphoma (DLBC) is composed of more varieties of one disease. Analysis and understanding of a wide range of characteristics of the disease, which include: clinical, immunohistochemical, cytogenetic and molecular characteristics may improve treatment results. Aim: achieving the estimated three-year survival and influence of IRF/MUM1 expression to three-year survival. Material and methods: A study was retrospective–prospective, patients were followed for seven years a period of dine. The study included 60 patients de novo DLBCL. Age was 18-72 years old, the average age 45 years, male 31 (51,7%) and female 29 (48.3%). Median follow-up was 47 months (3-91 months). To determine differentiation immunophenotype antibodies those were used anti-CD20, anti-CD10, anti-Bcl-6, IRF-4/MUM1, CD 138. Results: Included the GCB type was 65%. Impact prognostic index IPI>2 GBC vs non GBC p=0,038 X2. Statistically significant difference was confirmed compared to the IPI> 2 to 3 year OS p<0,0005 X2. Significantly longer three-year survival was provided in the group GCB 36 (92,3%) vs. non GCB 8 (38,1%) p=0,003 X2. Clinical and immunohistochemical factors showed a significant impact to three-year survival by univariate: LDH p=0,005, MUM1 p=0,003, while CD10 p=0,069 was confirmed on the level of borderline impact. Using multivariate analysis, expression MUM1 has the greatest impact p<0.0005 OR=0.083 (95% CI 0.23-0.303) on the disease outcome – three-year survival. Conclusion: expression MUM1 >25% has the greatest impact on the disease outcome – three-year survival. PMID:27994293

  10. INFRARED SPECTRAL ENERGY DISTRIBUTIONS OF SEYFERT GALAXIES: SPITZER SPACE TELESCOPE OBSERVATIONS OF THE 12 {mu}m SAMPLE OF ACTIVE GALAXIES

    SciTech Connect

    Gallimore, J. F.; Yzaguirre, A.; Jakoboski, J.; Stevenosky, M. J.; Axon, D. J.; O'Dea, C. P.; Robinson, A.; Baum, S. A.; Buchanan, C. L.; Elitzur, M.; Elvis, M.

    2010-03-01

    The mid-infrared spectral energy distributions (SEDs) of 83 active galaxies, mostly Seyfert galaxies, selected from the extended 12 {mu}m sample are presented. The data were collected using all three instruments, Infrared Array Camera (IRAC), Infrared Spectrograph (IRS), and Multiband Imaging Photometer for Spitzer (MIPS), aboard the Spitzer Space Telescope. The IRS data were obtained in spectral mapping mode, and the photometric data from IRAC and IRS were extracted from matched, 20'' diameter circular apertures. The MIPS data were obtained in SED mode, providing very low-resolution spectroscopy (R {approx} 20) between {approx}55 and 90 {mu}m in a larger, 20'' x 30'' synthetic aperture. We further present the data from a spectral decomposition of the SEDs, including equivalent widths and fluxes of key emission lines; silicate 10 {mu}m and 18 {mu}m emission and absorption strengths; IRAC magnitudes; and mid-far-infrared spectral indices. Finally, we examine the SEDs averaged within optical classifications of activity. We find that the infrared SEDs of Seyfert 1s and Seyfert 2s with hidden broad line regions (HBLRs, as revealed by spectropolarimetry or other technique) are qualitatively similar, except that Seyfert 1s show silicate emission and HBLR Seyfert 2s show silicate absorption. The infrared SEDs of other classes within the 12 {mu}m sample, including Seyfert 1.8-1.9, non-HBLR Seyfert 2 (not yet shown to hide a type 1 nucleus), LINER, and H II galaxies, appear to be dominated by star formation, as evidenced by blue IRAC colors, strong polycyclic aromatic hydrocarbon emission, and strong far-infrared continuum emission, measured relative to mid-infrared continuum emission.

  11. Wavelengths effective in induction of malignant melanoma.

    PubMed Central

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

    1993-01-01

    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. Images Fig. 4 PMID:8341684

  12. 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.

  13. Sub-wavelength focusing meta-lens.

    PubMed

    Roy, Tapashree; Rogers, Edward T F; Zheludev, Nikolay I

    2013-03-25

    We show that a planar plasmonic metamaterial with spatially variable meta-atom parameters can focus transmitted light into sub-wavelength hot-spots located beyond the near-field of the metamaterial. By nano-structuring a gold film we created an array of meta-lenses generating foci of 160 nm (0.2λ) in diameter when illuminated by a wavelength of 800 nm. We attribute the occurrence of sub-wavelength hotspots beyond the near field to the phenomenon of superoscillation.

  14. High Power Short Wavelength Laser Development

    DTIC Science & Technology

    1977-11-01

    Unlimited güä^äsjäsiiiüüü X NRTC-77-43R P I High Power Short Wavelength Laser Development November 1977 D. B. Cohn and W. B. Lacina...NO NRTC-77-43R, «. TITLE fana »uetjjitj BEFORE COMPLETING FORM CIPIENT’S CATALOO NUMBER KIGH.POWER SHORT WAVELENGTH LASER DEVELOPMENT , 7...fWhtn Data Enterte NRTC-77-43R HIGH POWER SHORT WAVELENGTH LASER DEVELOPMENT ARPA Order Number: Program Code Number: Contract Number: Principal

  15. 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.

  16. Wavelength multicasting in silicon photonic nanowires.

    PubMed

    Biberman, Aleksandr; Lee, Benjamin G; Turner-Foster, Amy C; Foster, Mark A; Lipson, Michal; Gaeta, Alexander L; Bergman, Keren

    2010-08-16

    We demonstrate a scalable, energy-efficient, and pragmatic method for high-bandwidth wavelength multicasting using FWM in silicon photonic nanowires. We experimentally validate up to a sixteen-way multicast of 40-Gb/s NRZ data using spectral and temporal responses, and evaluate the resulting data integrity degradation using BER measurements and power penalty performance metrics. We further examine the impact of this wavelength multicasting scalability on conversion efficiency. Finally, we experimentally evaluate up to a three-way multicast of 160-Gb/s pulsed-RZ data using spectral and temporal responses, representing the first on-chip wavelength multicasting of pulsed-RZ data.

  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. Magic wavelengths for terahertz clock transitions

    NASA Astrophysics Data System (ADS)

    Zhou, Xiaoji; Xu, Xia; Chen, Xuzong; Chen, Jingbiao

    2010-01-01

    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 3P0, 3P1, and 3P2 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.

  19. Apparatus for shifting the wavelength of light

    DOEpatents

    McCulla, William H.; Allen, Jr., John D.

    1983-01-01

    A light beam is reflected back and forth between a rotating body having a retroreflection corner at opposite ends thereof and a fixed mirror to change the wavelength of the light beam by the Doppler effect.

  20. Low Noise Mid-Wavelength IR Photodetectors

    DTIC Science & Technology

    2014-02-19

    Several ICIP structures were grown by MBE and fabricated into devices with a cut -off wavelength near 4-5 µm. Experimental results obtained from these... cut -off wavelength near 4-5 µm. Experimental results obtained from these devices have indicated improved device performance at high temperatures...zone (3), consisting of several GaSb/AlSb QWs. Zone (2) is composed of a series of digitally-graded InAs/AlSb QWs that form an energy ladder with

  1. SALSA - A lunar submillimeter-wavelength array

    NASA Technical Reports Server (NTRS)

    Mahoney, M. J.; Marsh, K. A.

    1992-01-01

    A conceptual design for a Synthesis Array for Lunar Submillimeter Astronomy (SALSA) is described with emphasis on information relevant to its implementation. SALSA is optimized to synthesize images of astronomical sources at wavelengths between 60 and 300 microns with an angular resolution of 10 milliarcseconds at the shortest wavelength. The discussion covers engineering considerations and descriptions of subsystems, including the environmental shield, antenna, and beam transport.

  2. 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

  3. 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.

  4. Applying the Power of Reticular Chemistry to Finding the Missing alb-MOF Platform Based on the (6,12)-Coordinated Edge-Transitive Net.

    PubMed

    Chen, Zhijie; Weseliński, Łukasz J; Adil, Karim; Belmabkhout, Youssef; Shkurenko, Aleksander; Jiang, Hao; Bhatt, Prashant M; Guillerm, Vincent; Dauzon, Emilie; Xue, Dong-Xu; O'Keeffe, Michael; Eddaoudi, Mohamed

    2017-03-01

    Highly connected and edge-transitive nets are of prime importance in crystal chemistry and are regarded as ideal blueprints for the rational design and construction of metal-organic frameworks (MOFs). We report the design and synthesis of highly connected MOFs based on reticulation of the sole two edge-transitive nets with a vertex figure as double six-membered-ring (d6R) building unit, namely the (4,12)-coordinated shp net (square and hexagonal-prism) and the (6,12)-coordinated alb net (aluminum diboride, hexagonal-prism and trigonal-prism). Decidedly, the combination of our recently isolated 12-connected (12-c) rare-earth (RE) nonanuclear [RE9(μ3-OH)12(μ3-O)2(O2C-)12] carboxylate-based cluster, points of extension matching the 12 vertices of hexagonal-prism d6R, with 4-connected (4-c) square porphyrinic tetracarboxylate ligand led to the formation of the targeted RE-shp-MOF. This is the first time that RE-MOFs based on 12-c molecular building blocks (MBBs), d6R building units, have been deliberately targeted and successfully isolated, paving the way for the long-awaited (6,12)-c MOF with alb topology. Indeed, combination of a custom-designed hexacarboxylate ligand with RE salts led to the formation of the first related alb-MOF, RE-alb-MOF. Intuitively, we successfully transplanted the alb topology to another chemical system and constructed the first indium-based alb-MOF, In-alb-MOF, by employing trinuclear [In3(μ3-O)(O2C-)6] as the requisite 6-connected trigonal-prism and purposely made a dodecacarboxylate ligand as a compatible 12-c MBB. Prominently, the dodecacarboxylate ligand was employed to transplant shp topology into copper-based MOFs by employing the copper paddlewheel [Cu2(O2C-)4] as the complementary square building unit, affording the first Cu-shp-MOF. We revealed that highly connected edge-transitive nets such shp and alb are ideal for topological transplantation and deliberate construction of related MOFs based on minimal edge-transitive nets.

  5. A SPECTROSCOPICALLY CONFIRMED EXCESS OF 24 mum SOURCES IN A SUPER GALAXY GROUP AT z = 0.37: ENHANCED DUSTY STAR FORMATION RELATIVE TO THE CLUSTER AND FIELD ENVIRONMENT

    SciTech Connect

    Tran, Kim-Vy H.; Saintonge, Amelie; Moustakas, John; Bai, Lei; Zaritsky, Dennis; Gonzalez, Anthony H.; Kautsch, Stefan J.; Holden, Bradford P.

    2009-11-01

    To trace how dust-obscured star formation varies with environment, we compare the fraction of 24 mum sources in a super galaxy group to the field and a rich galaxy cluster at z approx 0.35. We draw on multi-wavelength observations{sup 9}Based on observations made with (1) The ESO telescopes at Paranal Observatories under program IDs 072.A-0367, 076.B-0362, 078.B-0409; (2) the NASA/ESA Hubble Space Telescope (GO-10499); STScI is operated by the association of Universities for Research in Astronomy, Inc. under the NASA contract NAS 5-26555; (3) the Spitzer Space Telescope, which is operated by the Jet Propulsion Laboratory, California Institute of Technology under a contract with NASA; support for this work was provided by NASA through an award issued by JPL/Caltech (GO-20683); (4) the Chandra X-ray Observatory Center, which is operated by the Smithsonian Astrophysical Observatory for and on behalf of the National Aeronautics Space Administration under contract NAS8-03060; and (5) the Magellan 6.5 m telescope operated by OCIW. that combine Hubble, Chandra, and Spitzer imaging with extensive optical spectroscopy (>1800 redshifts) to isolate galaxies in each environment and thus ensure a uniform analysis. We focus on the four galaxy groups (sigma{sub 1D} = 303-580 km s{sup -1}) in supergroup 1120-12 that will merge to form a galaxy cluster comparable in mass to Coma. We find that (1) the fraction of supergroup galaxies with SFR{sub IR} >= 3 M {sub sun} yr{sup -1} is 4 times higher than in the cluster (32% +- 5% versus 7% +- 2%); (2) the supergroup's infrared luminosity function confirms that it has a higher density of IR members compared to the cluster and includes bright IR sources (log(L {sub IR})[erg s{sup -1}] >45) not found in galaxy clusters at z approx< 0.35; and (3) there is a strong trend of decreasing 24 mum fraction with increasing galaxy density, i.e., an infrared-density relation, not observed in the cluster. These dramatic differences are surprising

  6. A first principles study on the solvation and structure of SO{sub 4}{sup 2-}(H{sub 2}O){sub n}, n=6-12

    SciTech Connect

    Gao Bing; Liu Zhifeng

    2004-11-01

    The structures of hydrated sulfate clusters, SO{sub 4}{sup 2-}(H{sub 2}O){sub n} with n=6-12, are obtained by density functional theory calculations. For SO{sub 4}{sup 2-}(H{sub 2}O){sub 12}, two structures with symmetric distribution of H{sub 2}O molecules around the sulfate group are favored in energy. The structures for the smaller clusters, SO{sub 4}{sup 2-}(H{sub 2}O){sub n} with n=6-11, are obtained by taking away one H{sub 2}O molecule successively from the two symmetric SO{sub 4}{sup 2-}(H{sub 2}O){sub 12} isomers. The hydrogen bonding between the sulfate O atoms and H{sub 2}O molecules are strong. So are the hydrogen bonds among H{sub 2}O molecules, which are facilitated by the structure of the polyatomic sulfate group. The solvation energy is quite large (often exceeding 15 kcal/mol). The patterns for structural and energy changes as the cluster size increases are very different from the well studied hydrated halide ions, although the competition between solute-solvent and solvent-solvent interactions is again an important factor. Ab initio molecular dynamics simulations also show 'crowding' effects in the first solvation of SO{sub 4}{sup 2-}(H{sub 2}O){sub 12} at raised temperature.

  7. The beneficial effects of game-based exercise using age-appropriate tennis lessons on the executive functions of 6-12-year-old children.

    PubMed

    Ishihara, Toru; Sugasawa, Shigemi; Matsuda, Yusuke; Mizuno, Masao

    2017-03-06

    This study evaluated the effects of two different types of tennis lessons-those involving a technique-based approach (TBA) and those involving a game-based approach (PLAY+STAY [P+S])-on the executive functions (EFs) of junior tennis players. Eighty-one tennis players (6-12 years old) were recruited and assigned to one of three groups: TBA, P+S, or watching TV (CONT). Subjects completed evaluations of EFs (inhibitory control, working memory, and cognitive flexibility) before and after 50min programs. The overall score for EFs improved significantly for both the P+S and TBA groups but not for the CONT group; indeed the CONT group showed no improvement in overall EFs. Furthermore, the overall EF score improved more for P+S participants than for those in TBA. Looking at components of EFs, the pattern for inhibitory control reflected the pattern for the overall EF index: Improvement in the P+S and TBA groups but not in the CONT group. Only the P+S group improved in working memory. Thus, playing tennis and practicing isolated tennis skills both improved EFs of junior players more than did watching TV, and game-based tennis lessons seem to hold more promise for improving EFs than drills of tennis skills.

  8. 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.

  9. 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.

  10. Le role du phytoplancton de petite taille (<20 mum) dans les variations des proprietes optiques des eaux du Saint-Laurent

    NASA Astrophysics Data System (ADS)

    Mas, Sebastien

    Les mesures satellitaires de couleur des oceans sont largement determinees par les proprietes optiques inherentes (IOPs) des eaux de surface. D'autre part, le phytoplancton de petite taille (<20 mum) est le plus souvent dominant dans les oceans, et peut donc etre une source importante de variation des IOPs dans les oceans. Dans ce contexte, le but principal de ce doctorat etait de definir l'impact du phytoplancton (<20 mum) sur les variations des proprietes optiques de l'Estuaire et du Golfe du Saint-Laurent (Canada). Afin d'atteindre cet objectif, il etait necessaire de determiner en milieu controle les facteurs de variabilite des proprietes optiques cellulaires et des IOPs du phytoplancton (<20 mum) des eaux du Saint-Laurent, et d'evaluer la contribution du phytoplancton (<20 mum) aux proprietes optiques totales des eaux du Saint-Laurent. Des experiences en laboratoire ont montre que les variations des proprietes optiques des cellules phytoplanctoniques soumises a un cycle jour-nuit, ainsi qu'a des changements concomitants d'intensite lumineuse, peuvent contribuer significativement a la variabilite des proprietes optiques observee en milieu naturel. D'autres experiences ont, quant a elles, mis en evidence que les variations des proprietes optiques des cellules phytoplanctoniques dues aux phases de croissance peuvent alterer les IOPs des oceans, particulierement pendant les periodes de floraison. De plus, la presence de bacteries et de particules detritiques peut egalement affecter la variabilite des IOPs totales, notamment la diffusion. Au printemps, dans l'Estuaire et le Golfe du Saint-Laurent, la contribution du phytoplancton <20 mum aux IOPs presentait des differences regionales evidentes pour les proprietes d'absorption et de diffusion. En plus de la variabilite spatiale, les proprietes optiques cellulaires presentaient des variations journalieres, et ce particulierement pour le picophytoplancton. Enfin, la plupart des differences observees dans les

  11. 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)

  12. Effect of temperature on the {sup 127}I{sub 2} fluorescence excited by He-Ne laser radiation (0.63 {mu}m)

    SciTech Connect

    Kireev, S.V.; Shnyrev, S.L.

    1994-10-01

    Effect of temperature on the fluorescence of molecular iodine-127 vapors excited by the 0.63 {mu}m radiation of a {sup 3}He-{sup 22}Ne laser was studied. It was shown that heating iodine vapors can increase the sensitivity of the iodine-127 detection by the laser-fluorescent method by approximately an order of magnitude. The main contribution to the fluorescence signal is made by the absorption line 6-3 P(33). 20 refs., 4 figs.

  13. 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.

  14. 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.

  15. 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.

  16. Effect of wavelength change in microholographic recording

    NASA Astrophysics Data System (ADS)

    Katayama, Ryuichi

    2016-09-01

    In microholographic recording, expensive laser diodes having no spectrum broadening (single mode) and no wavelength variation are used. On the other hand, in conventional optical disk systems, cheap laser diodes having spectrum broadening (multimode) and wavelength variation are used. It is a great advantage if the laser diodes for conventional optical disk systems can be used for microholographic recording. Therefore, the effect of wavelength change in microholographic recording was investigated through a numerical simulation. The laser diodes were modeled so that the full width at 1/e2 maximum of the spectrum was 0.8 nm and the center wavelength was 405 nm. The numerical aperture of the objective lenses was 0.85 and the thickness of the recording medium was 300 μm. The diffraction efficiency of the diffracted beam from a microhologram was calculated using the coupled wave theory and the following results were obtained. The diffraction efficiency decreased by three orders of magnitude by replacing single-mode laser diodes with multimode laser diodes, which makes it necessary to enhance the readout signal. The tolerance of the optical path length difference between the signal and reference beams was -50 110 μm, which makes it necessary to adjust the optical path length difference. The tolerance of the wavelength variation was 405 +/- 0.5 nm, which makes it necessary to select the laser diodes. The conclusion was that it is not practical to use the laser diodes for conventional optical disk systems for microholographic recording.

  17. Wavelength-codified fiber laser hydrogen detector

    NASA Astrophysics Data System (ADS)

    Ortigosa-Blanch, A.; Díez, A.; González-Segura, A.; Cruz, J. L.; Andrés, M. V.

    2005-11-01

    We report a scheme for an optical hydrogen detector that codifies the information in wavelength. The system is based on an erbium-doped fiber laser with two coupled cavities and a Palladium-coated tapered fiber within one of the laser cavities. The tapered fiber acts as the hydrogen-sensing element. When the sensing element is exposed to a hydrogen atmosphere, its attenuation decreases changing the cavity losses. This change leads the system to switch lasing from the wavelength of the auxiliary cavity to the characteristic wavelength of the cavity which contains the sensing element. The detection level can be shifted by adjusting the reflective elements of the cavity containing the sensing element.

  18. 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.

  19. 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.

  20. 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.

  1. Wavelength Dependence on the Space Charge Collection

    SciTech Connect

    Washington, A.; Teague, L.; Duff, M.; Burger, A.; Groza, M.; Buliga, V.

    2012-05-31

    The distribution of the internal electric field in Cd{sub 1-x}Zn{sub x}Te (CZT) materials has significant effects on the charge collection ability. Light exposure at various wavelengths is a relatively unexplored process that alters charge collection at the anode contact. The use of multiple wavelengths can target charge carriers at various trap energies and positions throughout the crystal. The controlled illumination increases charge collection by releasing trapped electron and hole carriers in the crystal despite differences in light energy. Our study presents the results from our investigation of the effect of external illumination of CZT on the internal electric field via the Pockels effect. The space charge collection is further analyzed based on location and intensity relative to the specific wavelength of illumination.

  2. 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

  3. 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

  4. Development of rotational movements, hand shaping, and accuracy in advance and withdrawal for the reach-to-eat movement in human infants aged 6-12 months.

    PubMed

    Sacrey, Lori-Ann R; Karl, Jenni M; Whishaw, Ian Q

    2012-06-01

    The reach-to-eat movement, transport of a hand to grasp an object that is withdrawn and placed in the mouth, is amongst the earliest developing functional movements of human infants. The present longitudinal study is the first description of the maturation of hand-rotation, hand shaping, and accuracy associated with the advance and withdrawal phases of the movement. Eight infants, aged 6-12 months, and eight adults, were video recorded as they reached for familiar objects or food items. Hand, arm, and trunk movements were assessed frame-by-frame with the Skilled Reaching Rating Scale, previously developed for the assessment of adult reaching, and supplementary kinematic analysis. Reach-to-eat maturation was characterized by three changes. First, for advance, a simple open hand transport gradually matured to a movement associated with pronation and hand shaping of the digits for precision grasping. Second, for withdrawal to the mouth, a direct withdrawal movement gradually became associated with hand supination that oriented the target object to the mouth. Third, associated with the maturation of rotational movements, inaccurate and fragmented hand transport and withdrawal movements developed into precise targeting of the hand-to-object and object-to-mouth. Across the age range, there was a decrease in bimanual reaching and an increase in right handed reaching. The results are discussed in relation to the idea that the maturation of the reach-to-eat movement involves the development of rotational and shaping movements of the hand and visual and somatosensory guidance of a preferred hand.

  5. ±J Ising model on mixed Archimedean lattices: (33,42), (32,4,3,4), (3,122), (4,6,12)

    NASA Astrophysics Data System (ADS)

    Lebrecht, W.; Valdés, J. F.

    2013-10-01

    This paper addresses the problem of finding analytical expressions describing the ground state properties of mixed Archimedean lattices over which a generalized Edwards-Anderson model (±J Ising model) is defined. A local frustration analysis is performed based on representative cells for (33,42), (32,4,3,4), (3,122) and (4,6,12) lattices, following the notation proposed by Grünbaum and Shephard. The concentration of ferromagnetic (F) bonds x is used as the independent variable in the analysis (1-x is the concentration for antiferromagnetic (A) bonds), where x spans the range [0.00,1.00]. The presence of A bonds brings frustration, whose clear manifestation is when bonds around the minimum possible circuit of bonds (plaquette) cannot be simultaneously satisfied. The distribution of curved (frustrated) plaquettes within the representative cell is determinant for the evaluation of the parameters of interest such as average frustration segment, energy per bond, and fractional content of unfrustrated bonds. Two methods are developed to cope with this analysis: one based on the direct probability of a plaquette being curved; the other one is based on the consideration of the different ways bonds contribute to the particular plaquette configuration. Exact numerical simulations on a large number of randomly generated samples associated to (33,42) and (32,4,3,4) lattices allow to validate the previously described theoretical analysis. It is found that the first method presents slight advantages over the second one. However, both methods give an excellent description for most of the range for x. The small deviations at specific intervals of x for each lattice are relevant to the self-imposed limitations of both methods due to practical reasons. A particular discussion for the point x=0.50 for each one of the four lattices also sheds light on the general trends of the properties described here.

  6. 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.

  7. Multi-wavelength Luminosity Functions of Galaxies

    NASA Technical Reports Server (NTRS)

    Gardner, J. P.; Miller, N. A.

    2002-01-01

    Multivariate or multi-wavelength luminosity functions will reveal the interplay between star formation, chemical evolution, and absorption and re-emission of dust within evolving galaxy populations. By using principal component analysis to reduce the dimensionality of the problem, we optimally extract the relevant photometric information from large galaxy catalogs. As a demonstration of the technique, we derive the multi-wavelength luminosity function for the galaxies in the released SDSS catalog, and compare the results with those obtained by traditional methods. This technique will be applicable to catalogs of galaxies from datasets obtained by 2MASS, and the SIRTF and GALEX missions.

  8. Multi-Wavelength Luminosity Functions of Galaxies

    NASA Technical Reports Server (NTRS)

    Gardner, Jonathan P.

    2002-01-01

    Multivariate or multi-wavelength luminosity functions will reveal the interplay between star formation, chemical evolution, and ab- sorption and re-emission of dust within evolving galaxy populations. By using principal component analysis to reduce the dimensionality of the problem, I optimally extract the relevant photometric information from large galaxy catalogs. As a demonstration of the technique, I derive the multi-wavelength luminosity function for the galaxies in the released SDSS catalog, and compare the results with those obtained by traditional methods. This technique will be applicable to catalogs of galaxies from datasets obtained by 2MASS, and the SIRTF and GALEX missions.

  9. 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.

  10. 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.

  11. New design for a wavelength demultiplexing device

    NASA Astrophysics Data System (ADS)

    Bethmann, Konrad; Orghici, Rozalia; Pichler, Elke; Zywietz, Urs; Schimdt, Thomas; Gleissner, Uwe; Kelb, Christian; Roth, Bernhard; Reinhardt, Carsten; Willer, Ulrike; Schade, Wolfgang

    2015-05-01

    Arrayed waveguide gratings (AWG) originally designed as demultiplexing device and manufactured with well established silicon wafer technology are already used successfully as compact spectrometers with high resolution1. In this paper, the concept of a new design for a wavelength demultiplexing device based on tailor-made polymers is presented. The motivation for a new design is a smaller footprint of the device and the avoidance of bended waveguides and the associated losses. Extensive simulations were performed to optimize the design. Using microscope projection lithography and hot embossing a first polymer based device was realized. Its characterization and the achieved performance in terms of resolution and covered wavelength range will be discussed.

  12. 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

  13. Suggested isosbestic wavelength calibration in clinical analyses.

    PubMed

    Hoxter, G

    1979-01-01

    I recommend the use of isosbestic points for conveniently checking the wavelength scale of spectrophotometers in the ultraviolet and visible regions. Colorimetric pH indicators, hemoglobin derivatives, and other radiation-absorbing substances that are convertible into stable isomers of different absorption spectra provide a means for calibrating many different wavelengths by comparing the absorptivities of these isomers in equimolar solutions. The method requires no special precautions and results are independent of substance concentration and temperature between 4 and 45 degrees C. Isosbestic calibration may be important for (e.g.) coenzyme-dependent dehydrogenase activity determinations and in quality assurance programs.

  14. New method for spectrofluorometer monochromator wavelength calibration.

    PubMed

    Paladini, A A; Erijman, L

    1988-09-01

    A method is presented for wavelength calibration of spectrofluorometer monochromators. It is based on the distortion that the characteristic absorption bands of glass filters (holmium or didymium oxide), commonly used for calibration of spectrophotometers, introduce in the emitted fluorescence of fluorophores like indole, diphenyl hexatriene, xylene or rhodamine 6G. Those filters or a well characterized absorber with sharp bands like benzene vapor can be used for the same purpose. The wavelength calibration accuracy obtained with this method is better than 0.1 nm, and requires no modification in the geometry of the spectrofluorometer sample compartment.

  15. 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.

  16. Optimal wavelength selection for noncontact reflection photoplethysmography

    NASA Astrophysics Data System (ADS)

    Corral Martinez, Luis F.; Paez, Gonzalo; Strojnik, Marija

    2011-08-01

    In this work, we obtain backscattered signals from human forehead for wavelengths from 380 to 980 nm. The results reveal bands with strong pulsatile signals that carry useful information. We describe those bands as the most suitable wavelengths in the visible and NIR regions from which heart and respiratory rate parameters can be derived using long distance non-contact reflection photoplethysmography analysis. The latter results show the feasibility of a novel technique for remotely detection of vital signs in humans. This technique, which may include morphological analysis or maps of tissue oxygenation, is a further step to real non-invasive remote monitoring of patients.

  17. Concepts for a short wavelength rf gun

    NASA Astrophysics Data System (ADS)

    Kuzikov, S. V.; Shchelkunov, S.; Vikharev, A. A.

    2017-03-01

    Three concepts of an rf gun to be operated at 0.1-10 mm wavelengths are considered. In all the concepts, the rf system exploits an accelerating traveling wave. In comparison with a classical decimeter standing-wave rf gun, we analyze the advantages of new concepts, available rf sources, and achievable beam parameters.

  18. Short wavelength radio observations of Saturn's rings

    NASA Technical Reports Server (NTRS)

    Janssen, M. A.

    1974-01-01

    Passive radio observations are discussed from 1 mm to 2 cm wavelengths. The interferometric technique was used to observe the brightness of the rings. The reflectivity and disk temperature are also considered. The differences between radio and radar observations are examined and discussed.

  19. 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.

  20. 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.

  1. Age-related changes in wavelength discrimination

    PubMed Central

    Shinomori, Keizo; Schefrin, Brooke E.; Werner, John S.

    2008-01-01

    Wavelength discrimination functions (420 to 620–650 nm) were measured for four younger (mean 30.9 years) and four older (mean 72.5 years) observers. Stimuli consisted of individually determined isoluminant monochromatic lights (10 Td) presented in each half of a 2° circular bipartite field with use of a Maxwellian-view optical system. A spatial two-alternative forced-choice method was used in combination with a staircase procedure to determine discrimination thresholds across the spectrum. Small but consistent elevations in discrimination thresholds were found for older compared with younger observers. Because the retinal illuminance of the stimuli was equated across all observers, these age-related losses in discrimination are attributable to neural changes. Analyses of these data reveal a significant change in Weber fraction across adulthood for a chromatically opponent pathway receiving primarily antagonistic signals from middle-wavelength-sensitive and long-wavelength-sensitive cones but not for a short-wavelength-sensitive cone pathway. PMID:11205976

  2. Pump noise cancellation in parametric wavelength converters.

    PubMed

    Ataie, Vahid; Myslivets, Evgeny; Wiberg, Andereas O J; Alic, Nikola; Radic, Stojan

    2012-12-10

    A novel technique for pump noise effect mitigation in parametric wavelength converters is introduced. The method relies on digital signal processing and effectively takes advantage of the correlation property between the pump and idler, imposed by the parametric interaction. A 4 dB improvement in receiver performance is demonstrated experimentally for the conventional 10 Gbps OOK signal converted over 20 nm.

  3. Aero-Optics at Shorter Wavelengths.

    DTIC Science & Technology

    1980-03-01

    heliostat 1.93 1788 60 coelostat 2.40 2161 60 Changing from a CO2 laser to an iodine laser gives a wavelength ratio of 1/8. Assuming S is fixed, the...thickness and velocity profile. When the wall is concave to the external flow, Gortler vortices may occur. Cooling or heating can alter boundary layer

  4. 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.

  5. 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.

  6. Fiber optics wavelength division multiplexing(components)

    NASA Technical Reports Server (NTRS)

    Hendricks, Herbert D.

    1985-01-01

    The long term objectives are to develop optical multiplexers/demultiplexers, different wavelength and modulation stable semiconductor lasers and high data rate transceivers, as well as to test and evaluate fiber optic networks applicable to the Space Station. Progress in each of the above areas is briefly discussed.

  7. Investigation of optimum wavelengths for oximetry

    NASA Astrophysics Data System (ADS)

    Huong, Audrey K. C.; Stockford, Ian M.; Crowe, John A.; Morgan, Stephen P.

    2009-07-01

    An evaluation of the optimum choice of wavelengths, when using the 'Modified Lambert-Beer law' to estimate blood oxygen saturation, that minimises the mean error across a range of oxygen saturation values is presented. The stability of this approach and its susceptibility to noise are also considered.

  8. Long wavelength gravity and topography anomalies

    NASA Technical Reports Server (NTRS)

    Watts, A. B.; Daly, S. F.

    1981-01-01

    It is shown that gravity and topography anomalies on the earth's surface may provide new information about deep processes occurring in the earth, such as those associated with mantle convection. Two main reasons are cited for this. The first is the steady improvement that has occurred in the resolution of the long wavelength gravity field, particularly in the wavelength range of a few hundred to a few thousand km, mainly due to increased coverage of terrestrial gravity measurements and the development of radar altimeters in orbiting satellites. The second reason is the large number of numerical and laboratory experiments of convection in the earth, including some with deformable upper and lower boundaries and temperature-dependent viscosity. The oceans are thought to hold the most promise for determining long wavelength gravity and topography anomalies, since their evolution has been relatively simple in comparison with that of the continents. It is also shown that good correlation between long wavelength gravity and topography anomalies exists over some portions of the ocean floor

  9. 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.

  10. Interleukin-1beta, -6, -12 and tumor necrosis factor-alpha expression in brains of dogs with canine distemper virus infection.

    PubMed

    Gröne, A; Alldinger, S; Baumgärtner, W

    2000-10-02

    Canine distemper virus infection in dogs is commonly associated with demyelinating central nervous system lesions. Investigations on viral protein expression by studying mRNA and protein distribution together with the characterization of CD4 and CD8 inflammatory cells and MHC class II up-regulation revealed a biphasic disease process. To further investigate the cellular interactions in the different plaque types the cerebella of 14 dogs with confirmed distemper infection were investigated for expression of interleukin (IL)-1beta, -6, -12 and tumor necrosis factor-alpha (TNF) by immunohistochemistry using rabbit polyclonal anti-cytokine antibodies. T-cells and astrocytes were identified with rabbit anti CD3- and GFAP-monoclonal and polyclonal antibodies, respectively; and microglia/macrophages were characterized by their ability to bind lectin from Bandeiraea simplicifolia (BS-1). To further name the cytokine expressing cells immunoenzymatic double staining using DAB and New Fuchsin was performed. White matter lesions were classified according to histopathological criteria into acute, subacute and chronic. Canine distemper virus nucleoprotein antigen was demonstrated in nearly all plaques, except in older plaques where virus was not present within the plaque but adjacent to the lesion. IL-1 expression was observed to varying degrees in all types of lesions. Most often IL-1 was present in CD3 and BS-1 positive cells in the brain parenchyma in earlier plaques and comprising perivascular cuffs found in chronic plaques. IL-6 expression was present in all lesions, and followed a similar distribution pattern as IL-1. IL-12 displayed very often a granular extracellular pattern of immunoreactivity, especially in the brain parenchyma, and was found only in individual perivascular cells. TNF staining, predominantly found in astrocytes, was present in lesions of various types; however, staining appeared to be stronger in acute lesions and decreased in chronic plaques. In the

  11. Prevalence and Factors Associated with Goitre among 6-12-year-old Children in a Rural Area of Karnataka in South India.

    PubMed

    Manjunath, Bhanu; Suman, G; Hemanth, T; Shivaraj, N S; Murthy, N S

    2016-01-01

    In India, endemic goitre is present in sub-Himalayan region and in pockets in states of Andhra Pradesh, Karnataka and Gujarat. Being a public health problem amenable for prevention, the assessment of prevalence of endemic goitre in an area helps in understanding whether the preventive strategies under National Iodine Deficiency Disorder Control Program (NIDDCP) have any impact on the control of endemic goitre. Hence, the current study was carried out to determine the prevalence, distribution and factors associated with iodine deficiency goitre among 6-12-year-old children in a rural area in south Karnataka. A cross-sectional study was conducted among 838 children, using a questionnaire adopted from Iodized Salt Program Assessment Tool and the tools prescribed by WHO for goitre survey. The prevalence of goitre in the study area was 21.9% (95% CI 19.2-24.8). There was higher prevalence of goitre among those having salt iodine <15 ppm than those with >15 ppm (P = 0.01; OR 1.59; 95% CI 1.10-2.29). In 10% of the children, urinary iodine excretion (UIE) was assessed and prevalence was higher among those with <100 μg/l of UIE than those with normal UIE, which was not statistically significant (P = 0.8, OR 1.36; 95% CI 0.62-2.96). Multiple logistic regression revealed that gender (P = 0.002; OR 1.7; 95% CI 1.21-2.35) was an independent variable associated with goitre. The study area was found to be moderately endemic for goitre based on the WHO criteria. Higher prevalence of goitre was found to be still associated with consumption of low iodized salt (<15 ppm) necessitating emphasis on monitoring of salt iodine levels in the study area. Though NIDDCP is being implemented since five decades in India, the burden of iodine deficiency disorders (IDDs) is still high demanding further impetus to the monitoring systems of the programme.

  12. Imaging Uranus at Submillimeter to Centimeter Wavelengths

    NASA Astrophysics Data System (ADS)

    Hofstadter, Mark D.; Butler, B. J.; Gurwell, M. A.

    2007-10-01

    We have been making regular observations of Uranus for the past several years, in part to search for variability associated with the 2007 equinox. We will present an analysis of our current data set, spanning wavelengths from 1 mm to 20 cm (using the SMA and VLA radio observatories), including our latest data collected in August of 2007. These wavelengths probe the atmosphere from pressures of 1 to 50 bars, which extends from the lower tropopause far into convectively dominated regions, and includes several altitudes of cloud formation. We have found that, at all our wavelengths, the planet appears symmetric, with both the north (spring) and south (fall) polar regions being radio bright. At pressures greater than a few bars, this is almost certainly due to the poles being depleted in atmospheric absorbers by convective processes (Hofstadter and Butler 2003, Icarus 165, 168-180). Near 1 bar, the bright poles could be due to the physical temperature being 5 K higher there than at the equator, or due to a strong depletion of CH4 vapor over the poles. A combination of the two seems likely, as compositional variations are consistent with the circulation inferred from several data sets, and 2 K temperature variations are found both in theoretical models (Friedson and Ingersoll 1987, Icarus 69, 135-156) and in Voyager infrared measurements made in 1986 during southern summer solstice (Hanel et al. 1986, Science 233, 70-74). We will discuss these results in the context of observations of Uranus made at other wavelengths, and recent images we have acquired of Neptune at radio wavelengths. This work was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under contract with NASA. We acknowledge the support of NASA's Planetary Astronomy program, and of the VLA and SMA observatories.

  13. High-Power fiber amplifier with widely tunable repetition rate, fixed pulse duration, and multiple output wavelengths.

    PubMed

    Schrader, Paul E; Farrow, Roger L; Kliner, Dahv A V; Fève, Jean-Philippe; Landru, Nicolas

    2006-11-27

    We report a pulsed, fiber-amplified microchip laser providing widely tunable repetition rate (7.1 - 27 kHz) with constant pulse duration (1.0 ns), pulse energy up to 0.41 mJ, linear output polarization, diffraction-limited beam quality (M(2) < 1.2), and < 1% pulse-energy fluctuations. The pulse duration was shown to minimize nonlinear effects that cause temporal and spectral distortion of the amplified pulses. This source employs passive Q-switching, single-stage single-pass amplification, and cw pumping, thus offering high efficiency, simplicity, and compact, rugged packaging for use in practical applications. The high peak power and high beam quality make this system an ideal pump source for nonlinear frequency conversion, and we demonstrated efficient harmonic generation and optical parametric generation of wavelengths from 213 nm to 4.4 mum with Watt-level output powers.

  14. 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}).

  15. 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.

  16. 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.

  17. Methods of controlling the emission wavelength in InAs/GaAsN/InGaAsN heterostructures on GaAs substrates

    SciTech Connect

    Mamutin, V. V. Egorov, A. Yu.; Kryzhanovskaya, N. V.; Mikhrin, V. S.; Nadtochy, A. M.; Pirogov, E. V.

    2008-07-15

    Studies of the properties of InGaAsN compounds and methods of controlling the emission wavelength in InAs/GaAsN/InGaAsN heterostructures grown by molecular beam epitaxy on GaAs substrates are reviewed. The results for different types of heterostructures with quantum-size InGaAsN layers are presented. Among those are (1) traditional InGaAsN quantum wells in a GaAs matrix, (2) InAs quantum dots embedded in an (In)GaAsN layer, and (3) strain-compensated superlattices InAs/GaAsN/InGaAsN with quantum wells and quantum dots. The methods used in the study allow controllable variations in the emission wavelength over the telecommunication range from 1.3 to 1.76 {mu}m at room temperature.

  18. 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

  19. 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.

  20. 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.

  1. 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.

  2. Discrete Wavelength-Locked External Cavity Laser

    NASA Technical Reports Server (NTRS)

    Pilgrim, Jeffrey S.; Silver, Joel A.

    2004-01-01

    A prototype improved external cavity laser (ECL) was demonstrated in the second phase of a continuing effort to develop wavelength-agile lasers for fiber-optic communications and trace-gas-sensing applications. This laser is designed to offer next-generation performance for incorporation into fiber-optic networks. By eliminating several optical components and simplifying others used in prior designs, the design of this laser reduces costs, making lasers of this type very competitive in a price-sensitive market. Diode lasers have become enabling devices for fiber optic networks because of their cost, compactness, and spectral properties. ECLs built around diode laser gain elements further enhance capabilities by virtue of their excellent spectral properties with significantly increased (relative to prior lasers) wavelength tuning ranges. It is essential to exploit the increased spectral coverage of ECLs while simultaneously insuring that they operate only at precisely defined communication channels (wavelengths). Heretofore, this requirement has typically been satisfied through incorporation of add-in optical components that lock the ECL output wavelengths to these specific channels. Such add-in components contribute substantially to the costs of ECL lasers to be used as sources for optical communication networks. Furthermore, the optical alignment of these components, needed to attain the required wavelength precision, is a non-trivial task and can contribute substantially to production costs. The design of the present improved ECL differs significantly from the designs of prior ECLs. The present design relies on inherent features of components already included within an ECL, with slight modifications so that these components perform their normal functions while simultaneously effecting locking to the required discrete wavelengths. Hence, add-in optical components and the associated cost of alignment can be eliminated. The figure shows the locking feedback signal

  3. Sinusoidal nonlinearity in wavelength-sweeping interferometry

    SciTech Connect

    Perret, Luc; Pfeiffer, Pierre

    2007-11-20

    We report the influence of the nonlinearities in the wavelength-sweeping speed on the resulting interferometric signals in an absolute distance interferometer. The sweeping signal is launched in the reference and target interferometers from an external cavity laser source. The experimental results demonstrate a good resolution in spite of the presence of nonlinearities in the wavelength sweep. These nonlinearities can be modeled by a sum of sinusoids. A simulation is then implemented to analyze the influence of their parameters. It shows that a sinusoidal nonlinearity is robust enough to give a good final measurement uncertainty through a Fourier transform technique. It can be concluded that an optimal value of frequency and amplitude exists in the case of a sinusoidal nonlinearity.

  4. Human wavelength discrimination of monochromatic light explained by optimal wavelength decoding of light of unknown intensity.

    PubMed

    Zhaoping, Li; Geisler, Wilson S; May, Keith A

    2011-01-01

    We show that human ability to discriminate the wavelength of monochromatic light can be understood as maximum likelihood decoding of the cone absorptions, with a signal processing efficiency that is independent of the wavelength. This work is built on the framework of ideal observer analysis of visual discrimination used in many previous works. A distinctive aspect of our work is that we highlight a perceptual confound that observers should confuse a change in input light wavelength with a change in input intensity. Hence a simple ideal observer model which assumes that an observer has a full knowledge of input intensity should over-estimate human ability in discriminating wavelengths of two inputs of unequal intensity. This confound also makes it difficult to consistently measure human ability in wavelength discrimination by asking observers to distinguish two input colors while matching their brightness. We argue that the best experimental method for reliable measurement of discrimination thresholds is the one of Pokorny and Smith, in which observers only need to distinguish two inputs, regardless of whether they differ in hue or brightness. We mathematically formulate wavelength discrimination under this wavelength-intensity confound and show a good agreement between our theoretical prediction and the behavioral data. Our analysis explains why the discrimination threshold varies with the input wavelength, and shows how sensitively the threshold depends on the relative densities of the three types of cones in the retina (and in particular predict discriminations in dichromats). Our mathematical formulation and solution can be applied to general problems of sensory discrimination when there is a perceptual confound from other sensory feature dimensions.

  5. 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.

  6. Synchronous two-wavelength temporal interferometry

    NASA Astrophysics Data System (ADS)

    Zhang, Xiaoqiong; Gao, Zhan; Qin, Jie; Li, Guangyu; Feng, Ziang; Wang, Shengjia

    2016-09-01

    Interferometry is an optical measuring method with the character of non-destructive, high sensitivity and high accuracy. However, its measurement range is limited by the phase ambiguity. Hence the method with two separate different wavelengths light source is introduced to enlarge the measurement range. As for the two-wavelength interferometry case, phase shifting is the traditional way to acquire the phase map, it needs to repeat the measurement twice, which means the measurement cannot be accomplished in real time. Hence to solve the problem, a temporal sequence interferometry has been used. This method can obtain the desired phase information in real time by using the Fourier transform methods of the interferogram recorded in a sequence while the object is being deformed. But, it is difficult to retrieve the phase information directly due to the multi extreme points in one period of the cosine function. In this paper, an algorithm based on the wavelet ridge analysis is adopted to retrieve the two wavelength phase fluctuation caused by the displacement simultaneously. The preliminary experiment is conducted and the results are compared with theoretical simulations to validate the proposed approach. The laser emits light with two wavelengths 532 nm and 473 nm, two separated interference patterns in time sequence are detected by the CCD camera in the same time. The overlapped interferograms of two colors are analyzed by this algorithm and the corresponding phase information are obtained. The maximum error value between the simulation and theory is 0.03 um and the relative error is 0.33%.

  7. 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.

  8. Intrinsic Wavelength Shifts in Stellar Spectra

    NASA Astrophysics Data System (ADS)

    Dravins, D.; Lindegren, L.; Ludwig, H.-G.; Madsen, S.

    2004-12-01

    Wavelengths of stellar spectral lines do not have the precise values `naively' expected from laboratory wavelengths merely Doppler-shifted by stellar radial motion. Slight displacements may originate as convective shifts (correlated velocity and brightness patterns in the photosphere), as gravitational redshifts, or perhaps be induced by wave motions. Intrinsic lineshifts thus reveal stellar surface structure, while possible periodic changes (during a stellar activity cycle, say) need to be segregated from variability induced by orbiting exoplanets. Absolute lineshifts can now be studied also in some stars other than the Sun, thanks to astrometric determinations of stellar radial motion. Comparisons between spectroscopic apparent radial velocities and astrometrically determined radial motions reveal greater spectral blueshifts in F-type stars than in the Sun (as theoretically expected from their more vigorous convection), further increasing in A-type stars (possibly due to atmospheric shockwaves). Solar spectral atlases, and high-resolution spectra (from UVES on ESO VLT) of a dozen solar-type stars are being surveyed for `unblended' photospheric lines of most atomic species with accurate laboratory wavelengths available. One aim is to understand the ultimate information content of stellar spectra, and in what detail it will be feasible to verify models of stellar atmospheric hydrodynamics. These may predict line asymmetries (bisectors) and shifts for widely different classes of lines, but there will not result any comparison with observations if such lines do not exist in real spectra. An expected near-future development in stellar physics is spatially resolved spectroscopy across stellar disks, enabled by optical interferometry and adaptive optics on very large telescopes. Stellar surface structure manifests itself in the center-to-limb wavelength changes along a stellar diameter, and their spatially resolved time variability, diagnostics which already now can be

  9. Robust Fixed-Wavelength Laser Eye Protection

    DTIC Science & Technology

    1994-06-01

    protection : ■ protection against a few known wavelengths, such as used by friendly forces, and ■ protection against lasers that are frequency-agile, or...for flashblindness protection but were too slow for use against lasers. Many goggle materials have been developed to protect against specific laser...hazard to the eyes offered by currently fielded range-finders and designators requires that eye protection against these devices be made available

  10. 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.

  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. Short wavelength striations on expanding plasma clouds

    SciTech Connect

    Winske, D.; Gary, S.P.

    1989-01-01

    The growth and evolution of short wavelength (

  13. Gas sensing using wavelength modulation spectroscopy

    NASA Astrophysics Data System (ADS)

    Viveiros, D.; Ribeiro, J.; Flores, D.; Ferreira, J.; Frazao, O.; Santos, J. L.; Baptista, J. M.

    2014-08-01

    An experimental setup has been developed for different gas species sensing based on the Wavelength Modulation Spectroscopy (WMS) principle. The target is the measurement of ammonia, carbon dioxide and methane concentrations. The WMS is a rather sensitive technique for detecting atomic/molecular species presenting the advantage that it can be used in the near-infrared region using optical telecommunications technology. In this technique, the laser wavelength and intensity are modulated applying a sine wave signal through the injection current, which allows the shift of the detection bandwidth to higher frequencies where laser intensity noise is reduced. The wavelength modulated laser light is tuned to the absorption line of the target gas and the absorption information can be retrieved by means of synchronous detection using a lock-in amplifier, where the amplitude of the second harmonic of the laser modulation frequency is proportional to the gas concentration. The amplitude of the second harmonic is normalised by the average laser intensity and detector gain through a LabVIEW® application, where the main advantage of normalising is that the effects of laser output power fluctuations and any variations in laser transmission, or optical-electrical detector gain are eliminated. Two types of sensing heads based on free space light propagation with different optical path length were used, permitting redundancy operation and technology validation.

  14. 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.

  15. 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.

  16. 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.

  17. RED SUPERGIANTS AS POTENTIAL TYPE IIn SUPERNOVA PROGENITORS: SPATIALLY RESOLVED 4.6 {mu}m CO EMISSION AROUND VY CMa AND BETELGEUSE

    SciTech Connect

    Smith, Nathan; Hinkle, Kenneth H.; Ryde, Nils E-mail: hinkle@noao.edu

    2009-03-15

    We present high-resolution 4.6 {mu}m CO spectra of the circumstellar environments of two red supergiants (RSGs) that are potential supernova (SN) progenitors: Betelgeuse and VY Canis Majoris (VY CMa). Around Betelgeuse, {sup 12}CO emission within {+-}3'' ({+-}12 km s{sup -1}) follows a mildly clumpy but otherwise spherical shell, smaller than its {approx}55'' shell in K I {lambda}7699. In stark contrast, 4.6 {mu}m CO emission around VY CMa is coincident with bright K I in its clumpy asymmetric reflection nebula, within {+-}5'' ({+-}40 km s{sup -1}) of the star. Our CO data reveal redshifted features not seen in K I spectra of VY CMa, indicating a more isotropic distribution of gas punctuated by randomly distributed asymmetric clumps. The relative CO and K I distribution in Betelgeuse arises from ionization effects within a steady wind, whereas in VY CMa, K I is emitted from skins of CO cloudlets resulting from episodic mass ejections 500-1000 yr ago. In both cases, CO and K I trace potential pre-SN circumstellar matter: we conclude that an extreme RSG like VY CMa might produce a Type IIn event like SN 1988Z if it were to explode in its current state, but Betelgeuse will not. VY CMa demonstrates that luminous blue variables are not necessarily the only progenitors of SNe IIn, but it underscores the requirement that SNe IIn suffer enhanced episodic mass loss shortly before exploding.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. Bibliography of Short Wavelength Chemical Laser Research

    DTIC Science & Technology

    1993-05-01

    shock tube dissociation of fluorine azide, (2) identify and characterize alternatives to BiF as the lasant in an excited NF driven laser , (3) develop...L.F. Phillips KINETICS OF 12 FOLLOWING ArF LASER EXCITATION: THERMAL DISSOCIATION OF THE A’(2u) STATE J. Phys. Chem., 88, 6084 (1984) 267. Tellinghuisen...VISIBLE WAVELENGTH CHEMICAL LASER SCHEMES BASED ON THERMAL DISSOCIATION OF CHLORINE AZIDE Proc. Int. Conf on.LASERS 󈨟, Eds. F.J. Duarte and D.G. Harris

  6. 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

  7. Multi-wavelength applications of gravitational lensing

    NASA Astrophysics Data System (ADS)

    Fadely, Ross

    2010-12-01

    Using an array of multi-wavelength data, we examine a variety of astrophysical problems with gravitational lensing. First, we seek to understand the mass distribution of an early-type galaxy with an analysis of the lens Q0957+561. We dissect the lens galaxy into luminous and dark components, and model the environment using results from weak lensing. Combining constraints from newly-discovered lensed images and stellar population models, we find the lens has a density profile which is shallower than isothermal, unlike those of typical early-type galaxies. Finally, using the measured time delay between the quasar images we find the Hubble constant to be H 0 = 79.3+6.7-8.5 km s-1 Mpc-1 . One intriguing application of lensing is to exploit the lens magnification boost to study high-redshift objects in greater detail than otherwise possible. Here, we analyze the mid-infrared properties of two lensed z ˜ 2 star-forming galaxies, SDSS J120602.09+514229.5 and SDSS J090122.37+181432.3, using Spitzer /IRS spectra to study their rest-frame ˜ 5-12 μm emission. Both systems exhibit strong polycyclic aromatic hydrocarbon (PAH) features in the spectra, indicating strong star formation and the absence of significant AGN activity. For SDSS J090122.37+181432.3, this detection belies that inferred from optical measurements, indicating mid-IR spectroscopy provides key information needed to understand the properties of high-redshift star-forming galaxies. While lensing provides measurements of the macroscopic properties of lens systems, it can also shed light on small-scale structure of galaxies. To identify and understand lens substructure, we examine the multi-wavelength properties of flux ratios for six lenses. Variations of the flux ratios with wavelength can be used to study the lensed quasars and the small-scale mass distribution of lens galaxies. We detect strong multi-wavelength variations in the lenses HE 0435-1223 and SDSS 0806+2006. For HE 0435-1223, we study its

  8. Imaging Antenna Structure For Submillimeter Wavelengths

    NASA Technical Reports Server (NTRS)

    Rebeiz, G.; Rutledge, D.

    1990-01-01

    Integrated-circuit antenna structure contains two-dimensional array of antennas and antenna reflectors. In receiving mode, each antenna acts as part of detector for one picture element in millimeter- or submillimeter-wavelength imaging radar system. Millimeter-wave imaging system used to view objects through fog, smoke, or smog with resolution intermediate between microwave and visible-light imaging systems. Antenna elements, supports, and reflectors made by integrated-circuit techniques. Structures fabricated on front and back substrates separately. Substrates then joined. Inexpensive way to provide large number of small antenna elements required for imaging, all mounted rigidly in way that does not degrade operation.

  9. a Self-Consistent Analysis of Far-Infrared and Submillimeter Wavelength Metal-Grating Free Electron Lasers.

    NASA Astrophysics Data System (ADS)

    Xu, Yansun

    A theoretical exploration of the characteristics and operational requirements of far-infrared and sub-millimeter wavelength Metal-Grating Free-Electron-Lasers is presented. In the device an open planar type of quasi-optical resonator is loaded with a strip of rectangular metal-grating, and driven by a moderate energy electron beam. The basic tuning features and energy storage capacity of the resonator are described by the dispersion relation of the periodic slow -wave structure. To give a complete description of electron and wave dynamics in the laser oscillator, a set of self -consistent equations are derived through the use of the Lorentz force equation and the Maxwell's equations. Small signal gain and output efficiency of the device are developed from the self-consistent model. The nonlinear saturation is examined with a strong-field technique which is based upon a simple nonlinear ordinary differential equation of Duffing type. A detailed evaluation of the start-current, optimum interaction length and output efficiency of the laser oscillator at far-infrared and sub-millimeter wavelength region, indicates that the operations at wavelengths from 1mm to 100mum could be optimized at the output efficiencies around 1% with the use of an 100keV to 1MeV electron beam of current densities from 10 to 100(A/cm{^2}) and a 10 to 20cm long grating section. A theory of klystron type Metal-Grating Free Electron Lasers is also developed. Results of the proof-of-principle tests in the lower-millimeter wavelength region show that the klystron type devices generate more coherent radiations with start-current below 0.5A, and output power and efficiency up to 600watts and 2% at about 35GHz.

  10. 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.

  11. Monolithic single mode interband cascade lasers with wide wavelength tunability

    NASA Astrophysics Data System (ADS)

    von Edlinger, M.; Weih, R.; Scheuermann, J.; Nähle, L.; Fischer, M.; Koeth, J.; Kamp, M.; Höfling, S.

    2016-11-01

    Monolithic two-section interband cascade lasers offering a wide wavelength tunability in the wavelength range around 3.7 μm are presented. Stable single mode emission in several wavelength channels was realized using the concept of binary superimposed gratings and two-segment Vernier-tuning. The wavelength selective elements in the two segments were based on specially designed lateral metal grating structures defined by electron beam lithography. A dual-step dry etch process provided electrical separation between the segments. Individual current control of the segments allowed wavelength channel selection as well as continuous wavelength tuning within channels. A discontinuous tuning range extending over 158 nm in up to six discrete wavelength channels was achieved. Mode hop free wavelength tuning up to 14 nm was observed within one channel. The devices can be operated in continuous wave mode up to 30 °C with the output powers of 3.5 mW around room temperature.

  12. 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.

  13. Dual-wavelength InP quantum dot lasers

    SciTech Connect

    Shutts, S.; Smowton, P. M.; Krysa, A. B.

    2014-06-16

    We have demonstrated a two-section dual-wavelength diode laser incorporating distributed Bragg reflectors, with a peak-wavelength separation of 62.5 nm at 300 K. Each lasing wavelength has a different temperature dependence, providing a difference-tuning of 0.11 nm/K. We discuss the mechanisms governing the light output of the two competing modes and explain how the short wavelength can be relatively insensitive to output changes at the longer wavelength. Starting from an initial condition when the output at both wavelengths are equal, a 500% increase in the long wavelength output causes the short wavelength output to fall by only 6%.

  14. Dye mixtures for ultrafast wavelength shifters

    SciTech Connect

    Gangopadhyay, S.; Liu, L.; Palsule, C.; Borst, W.; Wigmans, R.; Barashkov, N.

    1994-12-31

    Particle detectors based on scintillation processes have been used since the discovery of radium about 100 years ago. The fast signals that can be obtained with these detectors, although often considered a nice asset, were rarely essential for the success of experiments. However, the new generation of high energy particle accelerators require particle detectors with fast response time. The authors have produced fast wavelength shifters using mixtures of various Coumarin dyes with DCM in epoxy-polymers (DGEBA+HHPA) and measured the properties of these wavelength shifters. The particular mixtures were chosen because there is a substantial overlap between the emission spectrum of Coumarin and the absorption spectrum of DCM. The continuous wave and time-resolved fluorescence spectra have been studied as a function of component concentration to optimize the decay times, emission peaks and quantum yields. The mean decay times of these mixtures are in the range of 2.5--4.5 ns. The mean decay time increases with an increase in Coumarin concentration at a fixed DCM concentration or with a decrease in DCM concentration at a fixed Coumarin concentration. This indicates that the energy transfer is radiative at lower relative DCM concentrations and becomes non-radiative at higher DCM concentrations.

  15. Wavelengths for EVE coronal dimming signatures

    NASA Astrophysics Data System (ADS)

    Hudson, H. S.; Simoes, P. J. D. A.; Kukstas, E.

    2014-12-01

    The EVE instrument on SDO detects post-flare dimmings, mainly in the spectral regions of Fe IX-XII in its MEGS-A range. We have shown that dimmings occurred in most of the 31 X-class flares that occurred between SDO launch and the end of April 2014. Based upon earlier X-ray observations, we interpret these dimmings as the result of CME mass ejections from the low corona. We can estimate the masses involved in these dimmings by deriving a best pre-event temperature and emission measure in the dimmed region from EVE, and a source volume from AIA images. The dimming for SOL2011-02-15, the first of these events, "peaked" at -3.4% in Fe IX in terms of the pre-event emission from the whole Sun, with smaller relative depletions in higher ionization states of Fe. Because of its high photon throughput, EVE data determine line centroids with precisions of a few km/s equivalent. In the present study we analyze the wavelengths of the dimmed regions, characterizing their displacements from the mean wavelengths as functions of heliographic position, time, event magnitude, and excitation state of Fe.

  16. Coherence techniques at extreme ultraviolet wavelengths

    SciTech Connect

    Chang, Chang

    2002-01-01

    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.

  17. Raman Amplifier Performance under New Wavelength Ranges

    NASA Astrophysics Data System (ADS)

    Khalaf, Ashraf A. M.; Mustafa, Fathy M.

    2016-03-01

    Due to the benefits of Raman amplifier (RA) for long-haul Ultra Wideband (UW)-WDM optical communications systems, we are studying and investigating how to widen the bandwidth and flatten the gain of RA by testing it in a new wider range of wavelengths (1.4 μm≤λsignal≤1.7 μm) instead of the benchmark range (1.45 μm≤λsignal≤1.65 μm). Four different ranges of signal wavelengths are used in this paper with the aim of testing the performance of RA model proposed in [13-15]: 1. 1.4 μm≤λsignal≤1.45 μm 2. 1.45 μm≤λsignal≤1.65 μm 3. 1.65 μm≤λsignal≤1.75 μm 4. 1.43 μm≤λsignal≤1.7 μm Different model sizes are used and analyzed to get wider bandwidth and more flat gain.

  18. Retinal injury thresholds for blue wavelength lasers.

    PubMed

    Lund, David J; Stuck, Bruce E; Edsall, Peter

    2006-05-01

    The interaction mechanism leading to laser-induced retinal alteration can be thermal or non-thermal, depending upon the wavelength of the laser radiation and the duration of the exposure. To investigate the effect of exposure duration on the interaction mechanism, retinal injury thresholds in the rhesus monkey were experimentally measured for exposure to laser radiation at wavelengths of 441.6, 457.9, 476.5, and 496.5 nm. Exposure durations were 0.1, 1, 5, 16, and 100 s; and 1/e retinal irradiance diameters were 50, 125, and 327 microm. Tissue response was observed via ophthalmoscope 1 h and 48 h post exposure. Thermal and non-thermal damage thresholds were obtained depending upon the exposure duration. These threshold data are in agreement with data previously reported in the literature for 100-s duration exposures, but differences were noted for shorter exposures. The current study yielded an estimated injury threshold for 1-s duration, 327-microm retinal irradiance diameter exposures at 441.6 nm, which is an order of magnitude higher than that previously reported. This study provides evidence that laser-induced retinal damage is primarily induced via thermal mechanisms for exposures shorter than 5 s in duration. Arguments are presented that support an amendment of the thermal hazard function, R(lambda).

  19. Long-Wavelength Instability in Marangoni Convection

    NASA Technical Reports Server (NTRS)

    VanHook, Stephen J.; Schatz, Michael F.; Swift, Jack B.; McCormick, W. D.; Swinney, Harry L.

    1996-01-01

    Our experiments in thin liquid layers (approximately 0.1 mm thick) heated from below reveal a well-defined long-wavelength instability: at a critical temperature difference across the layer, the depth of the layer in the center of the cell spontaneously decreases until the liquid-air interface ruptures and a dry spot forms. The onset of this critical instability occurs at a temperature difference across the liquid layer that is 35% smaller than that predicted in earlier theoretical studies of a single layer model. Our analysis of a two-layer model yields predictions in accord with the observations for liquid layer depths greater than or equal to 0.15 mm, but for smaller depths there is an increasing difference between our predictions and observations (the difference is 25% for a layer 0.06 mm thick). In microgravity environments the long-wavelength instability observed in our terrestrial experiments is expected to replace cellular convection as the primary instability in thick as well as thin liquid layers heated quasistatically from below.

  20. 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.

  1. 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.

  2. Light scattering by irregular particles much larger than the wavelength with wavelength-scale surface roughness.

    PubMed

    Grynko, Yevgen; Shkuratov, Yuriy; Förstner, Jens

    2016-08-01

    We simulate light scattering by random irregular particles that have dimensions much larger than the wavelength of incident light at the size parameter of X=200 using the discontinuous Galerkin time domain method. A comparison of the DGTD solution for smoothly faceted particles with that obtained with a geometric optics model shows good agreement for the scattering angle curves of intensity and polarization. If a wavelength-scale surface roughness is introduced, diffuse scattering at rough interface results in smooth and featureless curves for all scattering matrix elements which is consistent with the laboratory measurements of real samples.

  3. 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.

  4. 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.

  5. 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."

  6. NH{sub 2}CH{sub 2}OH THERMAL FORMATION IN INTERSTELLAR ICES CONTRIBUTION TO THE 5-8 mum REGION TOWARD EMBEDDED PROTOSTARS

    SciTech Connect

    Bossa, J. B.; Theule, P.; Duvernay, F.; Chiavassa, T.

    2009-12-20

    Aminomethanol (NH{sub 2}CH{sub 2}OH) is formed at low temperature from the purely thermal reaction of NH{sub 3} and H{sub 2}CO in laboratory interstellar ice analogs. We report for the first time its infrared and mass spectra. We study its reaction and desorption kinetics using Fourier transform infrared spectroscopy and mass spectrometry. Its reaction rate is estimated to be k(T) = 0.05 x exp(-4.5(kJ mol{sup -1})/RT) and its desorption energy to be E{sub des} = 58 +- 2 kJ mol{sup -1}. NH{sub 2}CH{sub 2}OH can also contribute to the 5-8 mum region of thermally processed ices encountered in many young stellar objects. Gas phase NH{sub 2}CH{sub 2}OH may be present in hot core regions, when the frozen material is desorbed.

  7. 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.

  8. 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.

  9. 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.

  10. 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

  11. MIPS 24 {mu}m OBSERVATIONS OF THE HUBBLE DEEP FIELD SOUTH: PROBING THE IR-RADIO CORRELATION OF GALAXIES AT z>1

    SciTech Connect

    Huynh, Minh T.; Gawiser, Eric; Marchesini, Danilo; Brammer, Gabriel; Guaita, Lucia

    2010-11-10

    We present MIPS 24 {mu}m observations of the Hubble Deep Field South taken with the Spitzer Space Telescope. The resulting image is 254 arcmin{sup 2} in size and has a sensitivity ranging between {approx}12 and {approx}30 {mu}Jy rms, with a median sensitivity of {approx}20 {mu}Jy rms. A total of 495 sources have been cataloged with a signal-to-noise ratio greater than 5{sigma}. The source catalog is presented as well as source counts which have been corrected for completeness and flux boosting. The IR sources are then combined with MUSYC optical/NIR and ATHDFS radio observations to obtain redshifts and radio flux densities of the sample. We use the IR/radio flux density ratio (q{sub 24}) to explore the IR-radio correlation for this IR sample and find q{sub 24} = 0.71 {+-} 0.31 for sources detected in both IR and radio. The results are extended by stacking IR sources not detected in the radio observations and we derive an average q{sub 24} for redshift bins between 0 < z < 2.5. We find that the high-redshift (z>1) sources have an average q{sub 24} ratio which is better fit by local LIRG SEDs rather than local ULIRG SEDs, indicating that high-redshift ULIRGs differ in their IR/radio properties. So, ULIRGs at high-redshift have SEDs different from those found locally. Infrared-faint radio sources are examined, and while nine radio sources do not have an MIPS detection and are therefore radio-loud active galactic nuclei (AGNs), only one radio source has an extreme IRAC 3.6 {mu}m to radio flux density ratio indicating it is a radio-loud AGN at z>1.

  12. 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.

  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. 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.

  15. Monitoring the stability of wavelength calibration of spectrophotometers.

    PubMed

    Korzun, W J; Miller, W G

    1986-01-01

    The difference in absorbance (delta A) between equimolar acid and alkaline solutions of methyl red, at a wavelength near the isosbestic point of the indicator, is reproducible. Furthermore, this delta A is sensitive to changes in the wavelength calibration of the instrument used to make the measurement. The delta A of methyl red can be used to monitor wavelength accuracy in both manual and automated spectrophotometric instruments. Although this measurement does not establish wavelength calibration, it is useful for monitoring the wavelength accuracy of previously calibrated, automated spectrophotometers that do not easily lend themselves to calibration checks by conventional techniques.

  16. Tunable optical tweezers for wavelength-dependent measurements.

    PubMed

    Hester, Brooke; Campbell, Gretchen K; López-Mariscal, Carlos; Filgueira, Carly Levin; Huschka, Ryan; Halas, Naomi J; Helmerson, Kristian

    2012-04-01

    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.

  17. Short-wavelength bottom-emitting VCSELs

    NASA Astrophysics Data System (ADS)

    Choquette, Kent D.; Barton, Jonathon S.; Geib, Kent M.; Allerman, Andrew A.; Hindi, Jana J.

    1999-04-01

    The fabrication and performance of selectively oxidized 850 nm vertical cavity surface emitting laser (VCSEL) diodes which emit through transparent GaP substrates is reported. Emission through the substrate is advantageous for many VCSEL configurations, such as for the incorporation of optical elements in the substrate or flip-chip integration to microelectronic circuitry. The short wavelength bottom- emitting VCSELs are fabricated by wafer fusion using an inert gas low temperature annealing process. The electrical characteristics of n- and p-type GaAs/GaAs and GaAs/GaP wafer bonded interfaces have been examined to optimize the annealing temperature. A significant reduction of the current-voltage characteristics of the VCSELs bonded to GaP substrates has been achieved whereby the bottom-emitting VCSELs show similar threshold voltage as compared to top- emitting lasers.

  18. 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.

  19. Polarization-Insensitive Metalenses at Visible Wavelengths.

    PubMed

    Khorasaninejad, M; Zhu, A Y; Roques-Carmes, C; Chen, W T; Oh, J; Mishra, I; Devlin, R C; Capasso, F

    2016-11-09

    In this Letter, we demonstrate highly efficient, polarization-insensitive planar lenses (metalenses) at red, green, and blue wavelengths (λ = 660, 532, and 405 nm). Metalenses with numerical apertures (NA) of 0.85 and 0.6 and corresponding efficiencies as high as 60% and 90% are achieved. These metalenses are less than 600 nm-thick and can focus incident light down to diffraction-limited spots as small as ∼0.64λ and provide high-resolution imaging. In addition, the focal spots are very symmetric with high Strehl ratios. The single step lithography and compatibility with large-scale fabrication processes make metalenses highly promising for widespread applications in imaging and spectroscopy.

  20. 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

  1. The Table Mountain 8-mm wavelength interferometer

    NASA Technical Reports Server (NTRS)

    Janssen, M. A.; Gary, B. L.; Gulkis, S.; Olsen, E. T.; Soltis, F. S.; Yamane, N. I.

    1979-01-01

    A two-element radio interferometer operating at 8.33-mm wavelength has been developed at the Jet Propulsion Laboratory's Table Mountain Observatory near Wrightwood, CA. The interferometer employs a 5.5-m and a 3-m diameter antenna on an east-west baseline of 60 or 120 m, yielding fringe spacings at transit of 28 or 14 arcsec, respectively. The broad intermediate-frequency bandpass of 100-350 MHz and the system noise temperature of 500 K provide high sensitivity for the measurement of continuum sources. The interferometer has been used for high-resolution studies of the planets and the sun, and it is currently being adapted to study solar flare emissions at high spatial and time resolution.

  2. Handheld four-wavelength retinal vessel oximeter

    NASA Astrophysics Data System (ADS)

    Heaton, Larry C.; Smith, Matthew H.; Denninghoff, Kurt R.; Hillman, Lloyd W.

    2000-06-01

    Several techniques for measuring the oxygen saturation of blood in retinal vessels have been reported. One interesting application of retinal vessel oximetry is the identification of occult blood loss in trauma victims. However, all the devices described to date are too bulky and cumbersome to be used in a trauma bay or in the field. We present a design for a handheld instrument that performs four-wavelength retinal vessel oximetry. This device is comparable in size and weight to a commercially available camcorder, and is suitable for use in the trauma bay. The compact size of this device could also extend its applications beyond traditional clinical settings, as it could be used by primary care physicians and home health care workers for the screening and monitoring of ophthalmic diseases. Principles of operation and preliminary data from the device will be described.

  3. 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.

  4. Analysis of stereoelectronic properties, mechanism of action and pharmacophore of synthetic indolo[2,1-b]quinazoline-6,12-dione derivatives in relation to antileishmanial activity using quantum chemical, cyclic voltammetry and 3-D-QSAR CATALYST procedures.

    PubMed

    Bhattacharjee, Apurba K; Skanchy, David J; Jennings, Barton; Hudson, Thomas H; Brendle, James J; Werbovetz, Karl A

    2002-06-01

    Several indolo[2,1-b]quinazoline-6,12-dione (tryptanthrin) derivatives exhibited remarkable activity at concentrations below 100 ng/mL when tested against in vitro Leishmania donovani amastigotes. The in vitro toxicity studies indicate that the compounds are fairly well tolerated in both macrophage and neuronal lines. An analysis based on qualitative and quantitative structure-activity relationship studies between in vitro antileishmanial activity and molecular electronic structure of 27 analogues of indolo[2,1-b]quinazoline-6,12-dione is presented here by using a combination of semi-empirical AM1 quantum chemical, cyclic voltammetry and a pharmacophore generation (CATALYST) methods. A modest to good correlation is observed between activity and a few calculated molecular properties such as molecular density, octanol-water partition coefficient, molecular orbital energies, and redox potentials. Electron transfer seems to be a plausible path in the mechanism of action of the compounds. A pharmacophore generated by using the 3-D QSAR of CATALYST produced a fairly accurate predictive model of antileishmanial activity of the tryptanthrins. The validity of the pharmacophore model extends to structurally different class of compounds that could open new frontiers for study. The carbonyl group of the five- and six-membered rings in the indolo[2,1-b]quinazoline-6,12-dione skeleton and the electron transfer ability to the carbonyl atom appear to be crucial for activity.

  5. 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.

  6. 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.

  7. Four-wavelength retinal vessel oximetry

    NASA Astrophysics Data System (ADS)

    Drewes, Jonathan Jensen

    1999-11-01

    This dissertation documents the design and construction of a four-wavelength retinal vessel oximeter, the Eye Oximeter (EOX). The EOX scans low-powered laser beams (at 629, 678, 821 and 899 nm) into the eye and across a targeted retinal vessel to measure the transmittance of the blood within the vessel. From the transmittance measurements, the oxygen saturation of the blood within the vessel is computed. Retinal vessel oxygen saturation has been suggested as a useful parameter for monitoring a wide range of conditions including occult blood loss and a variety of ophthalmic diseases. An artificial eye that simulates the geometry of a human retinal vessel was constructed and used to calibrate the EOX saturation measurement. A number of different oximetry equations were developed and tested. From measurements made on whole human blood in the artificial eye, an oximetry equation that places a linear wavelength dependance on the scattering losses (3% decrease from 629 to 899 nm) is found to best calibrate the EOX oxygen saturation measurement. This calibration also requires that an adjustment be made to the absorption coefficient of hemoglobin at 629 nm that has been reported in the literature. More than 4,000 measurements were made in the eyes of three human subjects during the development of the EOX. Applying the oximetry equation developed through the in vitro experiments to human data, the average human retinal venous oxygen saturation is estimated to be 0.63 +/- 0.07 and the average human retinal arterial oxygen saturation is 0.99 +/- 0.03. Furthermore, measurements made away from the optic disk resulted in a larger variance in the calculated saturation when compared to measurements made on the optic disk. A series of EOX experiments using anesthetized swine helped to verify the sensitivity of the EOX measurement of oxygen saturation. It is found that the calibration in swine differed from the calibration in the artificial eye. An empirical calibration from the

  8. Free-space optics wavelength selection: 10 µm versus shorter wavelengths [Invited

    NASA Astrophysics Data System (ADS)

    Achour, Maha

    2003-06-01

    Here I address the many inquiries about 10-µm free-space optics (FSO) performance compared with that of shorter wavelengths. The growing interest in better understanding FSO weather effects is the result of carrier requests as well as recent progress in analyzing fog effects on FSO signal propagation. Extensive studies in modeling fog and simulating FSO attenuations revealed the complexity behind estimating FSO link availability in a given geographical location. There are many different types of fog that are inhomogeneous along the propagation path. Each type is characterized by water-droplet size and concentration; these parameters are used in Mie scattering theory to compute FSO signal attenuation. As a result, some vendors are augmenting their FSO links with a microwave backup link or simply investigating other wavelengths claimed to be more resistant to fog such as 10 µm. Here I analyze ways to improve FSO link availability, 10-µm improvement compared with shorter wavelengths, and challenges behind successful microwave backup installation.

  9. A stable and inexpensive wavelength reference for precise wavelength calibration of radial velocity spectrographs

    NASA Astrophysics Data System (ADS)

    Feger, Tobias; Ireland, Michael J.; Bento, Joao; Bacigalupo, Carlos

    2014-08-01

    We present a stable, inexpensive wavelength reference, based on a white-light interferometer for the use on current and future (arrays of) diffraction-limited radial velocity (RV) spectrographs. The primary aim of using an interferometer is to obtain a dense sinusoidal wavelength reference with spectral coverage between 450-650 nm. Its basic setup consists of an unbalanced fiber Mach-Zehnder interferometer (FMZI) that creates an interference pattern in the spectral domain due to superposition of phase delayed light, set by a fixed optical path-length difference (OPD). To achieve long-term stability, the interferometer is actively locked to a stable atomic line. The system operates in closed-loop using a thermo-optic modulator as the phase feedback component. We conducted stability measurements by superimposing the wavelength reference with thorium-argon (ThAr) emission lines and found the differential RMS shift to be ~5 m s-1 within 30 minute bins in an experiment lasting 5 hours.

  10. 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

  11. 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

  12. 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.

  13. 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%.

  14. Convolution kernels for multi-wavelength imaging

    NASA Astrophysics Data System (ADS)

    Boucaud, A.; Bocchio, M.; Abergel, A.; Orieux, F.; Dole, H.; Hadj-Youcef, M. A.

    2016-12-01

    Astrophysical images issued from different instruments and/or spectral bands often require to be processed together, either for fitting or comparison purposes. However each image is affected by an instrumental response, also known as point-spread function (PSF), that depends on the characteristics of the instrument as well as the wavelength and the observing strategy. Given the knowledge of the PSF in each band, a straightforward way of processing images is to homogenise them all to a target PSF using convolution kernels, so that they appear as if they had been acquired by the same instrument. We propose an algorithm that generates such PSF-matching kernels, based on Wiener filtering with a tunable regularisation parameter. This method ensures all anisotropic features in the PSFs to be taken into account. We compare our method to existing procedures using measured Herschel/PACS and SPIRE PSFs and simulated JWST/MIRI PSFs. Significant gains up to two orders of magnitude are obtained with respect to the use of kernels computed assuming Gaussian or circularised PSFs. A software to compute these kernels is available at https://github.com/aboucaud/pypher

  15. ELTS, interferometers, and hypertelescopes at different wavelengths

    NASA Astrophysics Data System (ADS)

    Labeyrie, Antoine

    2008-04-01

    In the way of major new instruments for ground-based optical astronomy, maximizing the science favors a large hypertelescope. If equipped with adaptive optics and a laser guide star, it can provide direct high-resolution images of faint extra-galactic and cosmological sources. The signal/(photon noise) ratio is theoretically higher than with interferometer schemes relying upon aperture synthesis, using a few large apertures to reconstruct images. The crowding limit on complex objects, the direct-imaging field, and the dynamic range are also improved with many small apertures. The adaptive phasing of hypertelescopes, achievable on bright stars with modified wave sensing techniques such as "dispersed speckle" analysis, is also achievable on very faint sources with a modified version of a laser guide star. This makes large hypertelescopes capable of observing cosmological deep fields of faint galaxies. Pending space versions, the size of which can in principle reach hundreds and thousands of kilometers, terrestrial hypertelescopes limited in size to one or two kilometers can be built at suitable sites and used efficiently from ultra-violet to millimeter wavelengths. Some sites can allow the coupling of a hypertelescope with an ELT, an alternate option which can also be efficient for imaging deep fields with a high-resolution.

  16. 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.

  17. 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.

  18. Micro unattended mobility system (MUMS)

    NASA Astrophysics Data System (ADS)

    Rudakevych, Pavlo; Greiner, Helen; Pletta, Bryan

    1999-07-01

    This report covers work under phase one of the Micro Unattended Mobility System project investigating the addition of a mobile sensor components to existing and future ground penetrator delivered unattended sensor systems. A typical unattended sensor strategy consists of air-dropping sensor packages into a target terrain for remote observation and intelligence gathering. Existing and planned unattended systems have no control over their location after the drop is complete. We propose to augment the capability of these sensing packages by giving them a degree of local mobility. From an assumed operational scenario, vehicle design specifications are identified that would be required for mission success. Three basic mobility concepts are presented and evaluated for their strengths and weaknesses in the proposed mission. The mobility concepts are grouped into wheeled, jumping, and crawling systems. Of the three mobility concepts discussed, the system that shows the most promise is presented in a more detailed design. This design consists of two side by side wheels which drag a reaction tail behind them. The control electronics, batteries, and drive motors are housed in a central body connected to the tail and two sensor payloads can be placed in the wheel hubs. This design is proposed for further development and testing in the second phase of this project.

  19. Investigating the wavelength dependency of dot gain in color print

    NASA Astrophysics Data System (ADS)

    Namedanian, Mahziar; Gooran, Sasan; Nyström, Daniel

    2011-01-01

    By separating the optical dot gain from the physical dot gain, it is possible to study different behaviors of color inks on different papers. In this study we are investigating the dependency of dot gain and wavelength in color print. Microscopic images have been used to separate optical and physical dot gain from each other. The optical behavior of primary color inks in different absorbing wavelength bands has been studied. It has been illustrated that the light scattering in the paper is wavelength independent, and therefore the Point Spread Function which indicates the probability of light scattering of the paper does not change in visible wavelengths (380 nm -700 nm). We have shown that it is possible to separate two printed color inks on one specific wavelength, due to the filtering behavior of the color inks. By considering the fact that light scattering in the paper is wavelength independent, it was possible to separately analyze the dot gain of each color.

  20. 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.

  1. Using Guide Wavelengths to Assess Far-Infrared Laser Emissions

    NASA Astrophysics Data System (ADS)

    DeShano, B.; Olivier, K.; Cain, B.; Zink, L. R.; Jackson, M.

    2014-09-01

    An optically pumped molecular laser system with a transverse excitation scheme has been used to observe 77 guide wavelengths associated with the modes of an oversized waveguide laser resonator. These guide wavelengths, spanning from 102.6 to 990.6 μm, were generated by a variety of lasing media, including methanol along with several symmetric- and asymmetric-top molecules. The guide wavelengths displayed several consistent characteristics when compared with their respective fundamental laser emissions: their wavelengths were about 0.47 % larger and their relative powers were at least a factor of ten weaker. The properties of these guide wavelengths were used to assess frequency and wavelength measurements associated with known far-infrared laser emissions. For several of these laser emissions, this prompted a reinvestigation and subsequent revision of their measured values. Five far-infrared laser frequencies were also measured for the first time.

  2. Using Guide Wavelengths to Assess Far-Infrared Laser Emissions

    NASA Astrophysics Data System (ADS)

    DeShano, B.; Olivier, K.; Cain, B.; Zink, L. R.; Jackson, M.

    2015-01-01

    An optically pumped molecular laser system with a transverse excitation scheme has been used to observe 77 guide wavelengths associated with the modes of an oversized waveguide laser resonator. These guide wavelengths, spanning from 102.6 to 990.6 μm, were generated by a variety of lasing media, including methanol along with several symmetric- and asymmetric-top molecules. The guide wavelengths displayed several consistent characteristics when compared with their respective fundamental laser emissions: their wavelengths were about 0.47 % larger and their relative powers were at least a factor of ten weaker. The properties of these guide wavelengths were used to assess frequency and wavelength measurements associated with known far-infrared laser emissions. For several of these laser emissions, this prompted a reinvestigation and subsequent revision of their measured values. Five far-infrared laser frequencies were also measured for the first time.

  3. 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.

  4. 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

    2015-06-05

    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.

  5. 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.

  6. Simultaneous two-wavelength Doppler phase-shifting digital holography.

    PubMed

    Barada, Daisuke; Kiire, Tomohiro; Sugisaka, Jun-ichiro; Kawata, Shigeo; Yatagai, Toyohiko

    2011-12-01

    This paper presents a method based on the use of an image sensor for obtaining the complex amplitudes of beams diffracted from an object at two different wavelengths. The complex amplitude for each wavelength is extracted by the Doppler phase-shifting method. The principle underlying the proposed method is experimentally verified by using the method with two lasers having different wavelengths to measure the surface shape of a concave mirror.

  7. 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.

  8. 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.

  9. Applications of photonic crystal in wavelength multiplex visualization

    NASA Astrophysics Data System (ADS)

    Qian, Shi; Lei, Zhang

    2016-10-01

    The triple-channel photonic crystal filters are proposed designed. These devices have advantages of better filtering effect and high wavelength accuracy. In wavelength multiplex visualization, these filters can bring different wavelength of view entering into eyes so that stereo images are formed. we discuss the problem about minimization of the angle shift .The simulation shows that higher-index material and more high-index material in a basic period can decrease the angle shift.

  10. Performance evaluation of distributed wavelength assignment in WDM optical networks

    NASA Astrophysics Data System (ADS)

    Hashiguchi, Tomohiro; Wang, Xi; Morikawa, Hiroyuki; Aoyama, Tomonori

    2004-04-01

    In WDM wavelength routed networks, prior to a data transfer, a call setup procedure is required to reserve a wavelength path between the source-destination node pairs. A distributed approach to a connection setup can achieve a very high speed, while improving the reliability and reducing the implementation cost of the networks. However, along with many advantages, several major challenges have been posed by the distributed scheme in how the management and allocation of wavelength could be efficiently carried out. In this thesis, we apply a distributed wavelength assignment algorithm named priority based wavelength assignment (PWA) that was originally proposed for the use in burst switched optical networks to the problem of reserving wavelengths of path reservation protocols in the distributed control optical networks. Instead of assigning wavelengths randomly, this approach lets each node select the "safest" wavelengths based on the information of wavelength utilization history, thus unnecessary future contention is prevented. The simulation results presented in this paper show that the proposed protocol can enhance the performance of the system without introducing any apparent drawbacks.

  11. 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.

  12. Characteristics of a cascaded grating multi wavelength dye laser

    NASA Astrophysics Data System (ADS)

    Rana, Paramjit; Sridhar, G.; Manohar, K. G.

    2016-12-01

    Characteristics of a multi wavelength dye laser in two cascaded grating resonator configurations are presented. DCM dye dissolved in ethanol, was transversely pumped by second harmonic of Nd:YAG laser and four wavelength, independently tunable, collinear dye laser operation was obtained in Cascaded Grazing Incidence Grating cavity (CGIG) and Hybrid CGIG with fourth grating in Littrow angle (HCGIG) configuration. Gain competition effect of all the sub-cavities was fully characterized and wavelength zones of operation were identified for each cavity for sustaining four wavelength operation. Overall efficiency of the oscillator was measured to be around 2% in CGIG and 7% in HCGIG.

  13. Multi-wavelength photoplethysmography method for skin arterial pulse extraction

    PubMed Central

    Liu, Jing; Yan, Bryan Ping-Yen; Dai, Wen-Xuan; Ding, Xiao-Rong; Zhang, Yuan-Ting; Zhao, Ni

    2016-01-01

    In this work, we present a multi-wavelength (MW) PPG method exploiting the wavelength dependence of light penetration in skin tissue to provide depth resolution of skin blood pulsation. The MW PPG system requires two to three light sources in different wavelengths and extracts the arterial blood pulsation through a multi-wavelength multi-layer light-skin interaction model, which removes the capillary pulsation (determined from the short-wavelength PPG signal) from the long-wavelength PPG signal using absorption weighting factors that are quasi-analytically calibrated. The extracted pulsations are used to calculate blood pressure (BP) through pulse transit time (PTT), and the results are compared with those obtained from the single wavelength PPG method. The comparative study is clinically performed on 20 subjects including 10 patients diagnosed with cardiovascular diseases and 10 healthy subjects. The result demonstrates that the MW PPG method significantly improves the measurement accuracy of systolic BP (SBP), reducing the mean absolute difference between the reference and the estimated SBP values from 5.7 mmHg (for single-wavelength PPG) to 2.9 mmHg (for three-wavelength PPG). PMID:27867733

  14. 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

  15. 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.

  16. 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.

  17. Spectroscopic measurements of SO(2) line parameters in the 9.2 mum atmospheric region and theoretical determination of self-broadening coefficients.

    PubMed

    Tasinato, Nicola; Charmet, Andrea Pietropolli; Stoppa, Paolo; Giorgianni, Santi; Buffa, Giovanni

    2010-01-28

    Sulfur dioxide is still the subject of numerous spectroscopic studies since it plays an active role in the chemistry of Earth's atmosphere and it is a molecule of proven astrophysical importance. In the present work we have determined the self-broadening and integrated absorption coefficients for several lines in the nu(1) band spectral region around 9.2 mum. Besides the parameters of the lines belonging to the nu(1) fundamental of (32)SO(2), also those for some rovibrational lines of the nu(1)+nu(2)-nu(2) hot band of the (32)SO(2) isotopologue and the nu(1) band of the (34)SO(2) isotopic species have been determined. The measurements have been carried out at 297 K using a tunable diode laser spectrometer. The self-broadening parameters have also been theoretically determined employing a semiclassical formalism based on the Anderson-Tsao-Curnutte approximation. The study has been completed with the determination of the vibrational cross sections of the three fundamental bands measured from the spectra recorded at a resolution of 0.2 cm(-1) using a Fourier transform infrared spectrometer.

  18. DETECTION OF THE 158 {mu}m [C II] TRANSITION AT z = 1.3: EVIDENCE FOR A GALAXY-WIDE STARBURST

    SciTech Connect

    Hailey-Dunsheath, S.; Nikola, T.; Stacey, G. J.; Oberst, T. E.; Parshley, S. C.; Benford, D. J.; Staguhn, J. G.; Tucker, C. E.

    2010-05-01

    We report the detection of 158 {mu}m [C II] fine-structure line emission from MIPS J142824.0+352619, a hyperluminous (L {sub IR} {approx} 10{sup 13} L {sub sun}) starburst galaxy at z = 1.3. The line is bright, corresponding to a fraction L {sub [CII]}/L {sub FIR} {approx} 2 x 10{sup -3} of the far-IR (FIR) continuum. The [C II], CO, and FIR continuum emission may be modeled as arising from photodissociation regions (PDRs) that have a characteristic gas density of n {approx} 10{sup 4.2} cm{sup -3}, and that are illuminated by a far-UV radiation field {approx}10{sup 3.2} times more intense than the local interstellar radiation field. The mass in these PDRs accounts for approximately half of the molecular gas mass in this galaxy. The L {sub [CII]}/L {sub FIR} ratio is higher than observed in local ultraluminous infrared galaxies or in the few high-redshift QSOs detected in [C II], but the L {sub [CII]}/L {sub FIR} and L {sub CO}/L {sub FIR} ratios are similar to the values seen in nearby starburst galaxies. This suggests that MIPS J142824.0+352619 is a scaled-up version of a starburst nucleus, with the burst extended over several kiloparsecs.

  19. 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.

  20. 0.5 {mu}m E/D AlGaAs/GaAs heterostructure field effect transistor technology with DFET threshold adjust implant

    SciTech Connect

    Baca, A.G.; Sherwin, M.E.; Zolper, J.C.; Shul, R.J.; Briggs, R.D.; Heise, J.A.; Robertson, P.J.; Hafich, M.F.

    1997-04-01

    A doped-channel heterostructure field effect transistor (H-FET) technology has been developed with self-aligned refractory gate processing and using both enhancement- and depletion-mode transistors. D-HFET devices are obtained with a threshold voltage adjust implant into material designed for E-HFET operation. Both E- and D-HFETs utilize W/WSi bilayer gates, sidewall spacers, and rapid thermal annealing for controlling short channel effects. The 0.5 {mu}m E- HFETs (D-HFETs) have been demonstrated with transconductance of 425 mS/mm (265-310 mS/mm) and f{sub t} of 45-50 GHz. Ring oscillator gate delays of 19 ps with a power of 0.6 mW have been demonstrated using direct coupled FET logic. These results are comparable to previous doped-channel HFET devices and circuits fabricated by selective reactive ion etching rather than ion implantation for threshold voltage adjustment.

  1. 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.

  2. Wavelength techniques for digital holographic memories

    NASA Astrophysics Data System (ADS)

    Lande, David

    Holographic storage is a technique to store and retrieve information spread out in a volume, in contrast to current optical devices which store information locally on a surface. It provides for parallel page-by-page recording and readout of data instead of the usual serial, bit-by-bit, technique, and offers much higher diffraction-limited capacity. Success in the development of a competitive holographic storage device then depends on its cost, compactness and reliability. Since the first digital demonstrations, considerable effort by various groups has been spent in the development of high performance, practical holographic systems. This thesis presents several contributions toward this goal, suitable for holographic storage in lithium niobate and other applicable media. An intuitive explanation of volume holography is given, and Fourier analysis is used to derive the diffraction- limited capacity of digital storage in the form of elementary refractive index gratings. The physics of photorefractive materials, which are commonly used in holographic recording, is then presented, along with an established phenomenological model for grating formation. Following an analysis of imaging and multiplexing, a completely automated storage system implementing wavelength-multiplexed holography is described and evaluated, highlighting the feasibility of systems with fewer optical and mechanical components. The volatility of information in photorefractive media is then addressed by a demonstration of optical fixing, a technique based on two-photon recording mechanisms. Such an all-optical technique removes the need for heating elements, high voltages, or other post-processing elements currently used in non-volatile systems. Two-photon recording is also used to modulate, or apodize, the amplitude of volume gratings within the crystal bulk, providing a flexible technique to reduce cross-talk noise between stored pages and optimize the system capacity. Finally, simulations of

  3. 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.

  4. 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

  5. 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)

  6. 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)

  7. THE MULTI-WAVELENGTH EXTREME STARBURST SAMPLE OF LUMINOUS GALAXIES. I. SAMPLE CHARACTERISTICS

    SciTech Connect

    Laag, Edward; Croft, Steve; Canalizo, Gabriela; Lacy, Mark

    2010-12-15

    This paper introduces the Multi-wavelength Extreme Starburst Sample (MESS), a new catalog of 138 star-forming galaxies (0.1 < z < 0.3) optically selected from the Sloan Digital Sky Survey using emission line strength diagnostics to have a high absolute star formation rate (SFR; minimum 11 M{sub sun} yr{sup -1} with median SFR {approx} 61 M{sub sun} yr{sup -1} based on a Kroupa initial mass function). The MESS was designed to complement samples of nearby star-forming galaxies such as the luminous infrared galaxies (LIRGs) and ultraviolet luminous galaxies (UVLGs). Observations using the Multi-band Imaging Photometer (24, 70, and 160 {mu}m channels) on the Spitzer Space Telescope indicate that the MESS galaxies have IR luminosities similar to those of LIRGs, with an estimated median L{sub TIR} {approx} 3 x 10{sup 11} L{sub sun}. The selection criteria for the MESS objects suggest they may be less obscured than typical far-IR-selected galaxies with similar estimated SFRs. Twenty out of 70 of the MESS objects detected in the Galaxy Evolution Explorer FUV band also appear to be UVLGs. We estimate the SFRs based directly on luminosities to determine the agreement for these methods in the MESS. We compare these estimates to the emission line strength technique, since the effective measurement of dust attenuation plays a central role in these methods. We apply an image stacking technique to the Very Large Array FIRST survey radio data to retrieve 1.4 GHz luminosity information for 3/4 of the sample covered by FIRST including sources too faint, and at too high a redshift, to be detected in FIRST. We also discuss the relationship between the MESS objects and samples selected through alternative criteria. Morphologies will be the subject of a forthcoming paper.

  8. 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.

  9. Astrochemistry at Millimetre and Submillimetre Wavelengths

    NASA Astrophysics Data System (ADS)

    Wirström, Eva, S.

    2009-12-01

    The focus of this thesis is a series of observational tests, aiming to clarify the chemical and physical origin of interstellar molecules. Spectral lines at millimetre and submillimetre wavelengths, caused by rotational transitions in CO, H2O, NH3, CH3OH, CH3SH, C2H3CN, and several of their isotopologues, have been observed towards regions of star-formation in the Galaxy. Maps of extended H2O and CO emission from the Orion nebula demonstrate that the water probably is localised to the photon-dominated region at the surface of the molecular cloud, at higher abundances than previously thought. Water is also observed in absorption from its ground-state towards the massive star-forming region Sgr B2. Curiously enough, a water abundance similar to the one reported for Orion is found in the low-excitation gas in one of the Galactic spiral arms. Ammonia absorption was also observed from diffuse spiral arm clouds along the same line-of-sight, but at about an order of magnitude lower abundance. The observed water and ammonia absorptions caused by the Sgr B2 cloud itself are successfully modelled without invoking a morphological component of hot gas. Two independent methods of analysis are applied to observations of methanol (CH3OH) and its 13C isotopologue in the cold envelopes of young stellar objects. Both methods indicate that methanol is mainly formed by hydrogenation of CO on cold dust grains. A study comparing the interstellar abundances of CH3SH (methyl mercaptan) and CH3OH unveil a possible trend of lower relative CH3SH abundances in more evolved objects. However, the significance of this trend, in relation to the chemical origin of these molecules, needs to be further investigated. In addition, searches for two pre-biotic molecules, namely vinyl acetylene (C2H3CCH) and amino acetonitrile (H2NCH2CN), resulting in improved upper abundance limits are presented. A comprehensive conclusion of this thesis is that in order to exploit the full capacity of high

  10. 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.

  11. Absorption spectrum of DNA for wavelengths greater than 300 nm

    SciTech Connect

    Sutherland, J.C.; Griffin, K.P.

    1981-06-01

    Although DNA absorption at wavelengths greater than 300 nm is much weaker than that at shorter wavelengths, this absorption seems to be responsible for much of the biological damage caused by solar radiation of wavelengths less than 320 nm. Accurate measurement of the absorption spectrum of DNA above 300 nm is complicated by turbidity characteristic of concentrated solutions of DNA. We have measured the absorption spectra of DNA from calf thymus, Clostridium perfringens, Escherichia coli, Micrococcus luteus, salmon testis, and human placenta using procedures which separate optical density due to true absorption from that due to turbidity. Above 300 nm, the relative absorption of DNA increases as a function of guanine-cytosine content, presumably because the absorption of guanine is much greater than the absorption of adenine at these wavelengths. This result suggests that the photophysical processes which follow absorption of a long-wavelength photon may, on the average, differ from those induced by shorter-wavelength photons. It may also explain the lower quantum yield for the killing of cells by wavelengths above 300 nm compared to that by shorter wavelengths.

  12. Corrections for Wavelength Variations in Precision Interferometric Displacement Measurements

    PubMed Central

    Stone, Jack; Phillips, Steven D.; Mandolfo, Gary A.

    1996-01-01

    Precision interferometric displacement measurements require deadpath corrections to account for variations in wavelength during the course of the measurement. This paper discusses common errors in applying deadpath corrections and describes the correction necessary to fully account for variations in wavelength. PMID:27805085

  13. 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…

  14. Cascaded wavelength division multiplexing for byte-wide optical interconnects

    SciTech Connect

    Deri, R. J.; Garrett, H. E.; Germelos, S.; Haigh,R. E.; Henderer, B. D.; Lowry, M. E.; Walker, J.D.

    1997-11-17

    We demonstrate a wavelength division multiplexing approach for byte-wide optical interconnects over multimode fiber optic ribbon cable using filters based on common plastic ferrules. A dual wavelength link with eight cascaded filter stages exhibits bit error rates {le}l0{sup -l4}.

  15. Wavelength-selective light quenching of biochemical fluorophores

    NASA Astrophysics Data System (ADS)

    Gryczynski, Ignacy; Kusba, Jozef; Lakowicz, Joseph R.

    1997-01-01

    The use of light quenching to selectively eliminate the emission of biochemical fluorophores based on the emission wavelength is described. To demonstrate the possibility of wavelength-selective light quenching, a mixture of two fluorophores, 4-(dimethylamino)-4'-cyanostillene (DCS) and Prodan, emitting at different wavelengths was examined first. The emission spectrum and intensity decay were altered by the 570-nm quenching pulse due to selective quenching of the longer wavelength emission of DCS. Quenching of the solvent-sensitive fluorophore partially bound to human serum albumin and partially in the aqueous phase was then examined. Light quenching with a long wavelength (570 nm) time-delayed pulse selectively quenched the Prodan fluorophore in the aqueous phase while in the presence of the Prodan bound to human serum albumin, which emitted at shorter wavelengths, was not quenched. Using one- beam short wavelength excitation and quenching, a selective quenching of the blue-shifted emission of ribonuclease T1 in the presence of the red-shifted emission of the tryptophan residue in adrenocorticotropic hormone was observed. In both systems wavelength-selective light quenching was demonstrated by a shift in the emission spectra, and by changes in the intensity decay consistent with preferential quenching of one species. Light quenching is instantly reversible by blocking or defocusing of the quenching beam. It can occur for inaccessible residues or in viscous solvents, and thus can be of wide applicability for resolving the complex emission of biological macromolecules.

  16. 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.

  17. Mach-Zehnder wavelength selective switch embedded with microring resonators

    NASA Astrophysics Data System (ADS)

    Miura, Kengo; Shoji, Yuya; Mizumoto, Tetsuya

    2017-02-01

    A wavelength selective switch is proposed for optical wavelength division multiplexing network applications with very short range interconnections. The proposed device uses a Mach-Zehnder interferometer configuration incorporating wavelength selective phase shifters composed of microring resonators between their two arms. Wavelength selectivity is provided by cascaded microring resonators, which are placed in proximity so that the increase in excess loss caused by the difference in resonant wavelengths can be minimized. An on/off switching ratio >20 dB is obtainable when the drop/through transmittance ratio of the cascaded microring resonators is >22 dB and the coupling efficiency deviation from 50% is <1% in the directional couplers constructing the Mach-Zehnder interferometer.

  18. Two-wavelength full-field heterodyne interferometric profilometry

    NASA Astrophysics Data System (ADS)

    Hsieh, Hung-Chih; Chen, Yen-Liang; Jian, Zhi-Chen; Wu, Wang-Tsung; Su, Der-Chin

    2009-02-01

    An alternative full-field interferometric profilometry is proposed by combining two-wavelength interferometry and heterodyne interferometry. A collimated heterodyne light is introduced into a modified Twyman-Green interferometer, the full-field interference signals are taken by a fast CMOS camera. The sampled intensities recorded by each pixel are fitted to derive a sinusoidal signal with the least-square sine wave fitting algorithm, and its phase can be obtained. Comparing the phase of the reference point, the relative phase of the pixel can be calculated. Next, the same measurement is made again at a different wavelength. The relative phase with respect to the effective wavelength can be calculated and the profile of the tested sample can be derived with the two-wavelength interferometric technique. Its validity is demonstrated. It has merits of both two-wavelength interferometry and heterodyne interferometry.

  19. 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.

  20. Analysis of a dual-wavelength surface reference radar technique

    NASA Technical Reports Server (NTRS)

    Meneghini, Robert; Jones, Jeffrey A.; Gesell, Leslie H.

    1987-01-01

    The use of the single-wavelength surface reference technique (SRT), the standard dual-wavelength technique (DWT), and dual-wavelength surface reference technique (DSRT) for measuring precipitation from space is analyzed, and the results are compared. The characteristics of the three methods are described, and the surface return powers during clear air conditions are measured. It is observed that the rain rate estimates obtained with the DWT and DSRT are identical in form, and the surface reflectance can be derived from the estimates by replacing the rain reflectivity statistics with those of the backscattering cross section of the surface. The data reveal that the DSRT is more applicable than the SRT when the wavelength correlation in the backscattering cross section of the surface is high or when the mean values of the backscattering cross section at the two wavelengths are nearly equal.

  1. 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.

  2. 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.

  3. Optimal wavelength band clustering for multispectral iris recognition.

    PubMed

    Gong, Yazhuo; Zhang, David; Shi, Pengfei; Yan, Jingqi

    2012-07-01

    This work explores the possibility of clustering spectral wavelengths based on the maximum dissimilarity of iris textures. The eventual goal is to determine how many bands of spectral wavelengths will be enough for iris multispectral fusion and to find these bands that will provide higher performance of iris multispectral recognition. A multispectral acquisition system was first designed for imaging the iris at narrow spectral bands in the range of 420 to 940 nm. Next, a set of 60 human iris images that correspond to the right and left eyes of 30 different subjects were acquired for an analysis. Finally, we determined that 3 clusters were enough to represent the 10 feature bands of spectral wavelengths using the agglomerative clustering based on two-dimensional principal component analysis. The experimental results suggest (1) the number, center, and composition of clusters of spectral wavelengths and (2) the higher performance of iris multispectral recognition based on a three wavelengths-bands fusion.

  4. 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.

  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. 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

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. Wavelength calibration with Fabry Perot Interferometers - yes we can!

    NASA Astrophysics Data System (ADS)

    Franziskus Bauer, Florian; Zechmeister, Mathias; Reiners, Ansgar

    2015-08-01

    Hollow-cathode lamps (HCLs) are used as default wavelength standard for spectroscopic measurements but have a number of well-known shortcomings. Advancing to cm/s precision in radial velocity experiments requires more stable calibration sources with more uniform line distributions. Fabry Perot Interferometers (FPI) are a practical alternative with a well-suited line distribution at relatively low cost. We present a simple method to characterize FPIs using standard HCLs and including the FPI spectrum in the wavelength calibration process. We propose to use the HCL wavelength solution to define a rough wavelength scale that is used to approximate the FPI peak positions. We assume that the FPI mirror distance is a smooth function of wavelength and utilize the large number of FPI peaks (typically 10^4) to consistently model all FPI peak wavelengths. With this approach, we anchor the dense FPI lines with the absolute HCL-scale combining their precision and accuracy. We test our method with the HARPS spectrograph and compare our wavelength calibration to one derived from a laser frequency comb (LFC) spectrum. Our combined HCL/FPI wavelength calibration removes the known, large-amplitude distortions of 50 m/s that occur in the HCL solution. Direct comparison with the LFC solution bears only small differences between the LFC and the HCL/FPI solutions and demonstrates that the HCL/FPI solution can overcome the most important shortcomings in HCL wavelength solutions. An FPI can provide an economical alternative to LFCs in particular for smaller projects.

  12. Estimates of SASE power in the short wavelength region

    SciTech Connect

    Kim, Kwang-Je

    1992-03-01

    Given a sufficiently bright electron beam, the self-amplified-spontaneous emission (SASE) can provide gigawatts of short wavelength coherent radiation. The advantages of SASE approach are that is requires neither optical cavity nor an imput seed laser. In this note, we estimate the peak power performance of SASE for wavelengths shorter than 1000 {Angstrom}. At each wavelength, we calculate the saturated power from a uniform parameter undulator and the enhanced power from a tapered undulator. The method described here is an adaptation of that discussed by L.H. Yu, who discussed the harmonic generation scheme with seeded laser, to the case of SASE.

  13. Planar Rowland spectrometer for fiber-optic wavelength demultiplexing

    NASA Technical Reports Server (NTRS)

    Yen, H. W.; Friedrich, H. R.; Morrison, R. J.; Tangonan, G. L.

    1981-01-01

    A planar Rowland spectrometer was fabricated and characterized as a wavelength demultiplexer for multimode fiber-optic applications. The spectrometer consisted of a planar multimode glass waveguide with two curved end faces and a cylindrical concave attached to one of the end faces. Semiconductor lasers with wavelengths between 0.825 and 0.845 micron were used for the measurements. Cross-talk isolation between two adjacent fibers with center-to-center separation of 175 microns (100 A in wavelength difference) was measured to be 18 dB. The device's performance was limited by grating diffraction efficiency, optical aberration, waveguide dispersion, and waveguide losses.

  14. Cascaded wavelength conversion as favorable application of nonlinear optical polymers.

    PubMed

    Kim, Min-Su; Ju, Jung Jin; Park, Seung Koo; Do, Jung Yun; Lee, Myung-Hyun

    2008-06-23

    Nonlinear optical (NLO) polymers have been considered promising materials for wavelength conversion at a low pump power. However, they have not been readily adopted to practical applications due to their high absorption coefficients, especially at a shorter interacting wavelength. Our theoretical analysis proves that the influence of absorption coefficients can be mitigated significantly in cascaded wavelength conversion (CWC) processes. According to our example study, maximum conversion efficiencies for CWC can compare even with those for second-harmonic generation in many NLO polymers. Thus CWC can become a pertinent application of NLO polymers. However, to obtain such efficient CWC, several realistic problems should be resolved in practical devices.

  15. 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.

  16. Terahertz probe for spectroscopy of sub-wavelength objects.

    PubMed

    Mitrofanov, Oleg; Renaud, Cyril C; Seeds, Alwyn J

    2012-03-12

    A system of two probes is designed for terahertz (THz) time-domain spectroscopy of sub-wavelength size objects. A twin-needle probe confines broadband THz pulses spatially by means of surface plasmon waves to a sub-wavelength spot smaller than 10 microns. The confined pulses are detected within the near-field zone of the twin-needle probe by a sub-wavelength aperture probe. The system allows THz spectroscopy to be applied to single micrometer-size objects in the 1-2.5THz region.

  17. 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.

  18. Tutorial on 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. This paper considers two WDM system designs that might be used with multimode fibers and gives a general description of the components which could be used to implement the system. 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.

  19. Coupled metal gap waveguides as plasmonic wavelength sorters.

    PubMed

    Kang, Zhiwen; Wang, Guo Ping

    2008-05-26

    We propose a coupled metal gap waveguide structure for realizing plasmonic wavelength sorters. Theoretical analysis from the coupled-wave theory reveals that wavelength dependent coupling length of guided surface plasmon polaritons contributes to the routing of different wavelengths to different output ports with reasonable high extinction ratio. The analytical results are confirmed by the finite-difference time-domain numerical simulations. Our result may provide an alternative way to construct nanoscale frequency multiplexers, routers, and sorters for nanophotonic integration and optical communication.

  20. Filamentation of ultrashort laser pulses of different wavelengths in argon

    NASA Astrophysics Data System (ADS)

    Qi, Xiexing; Lin, Wenbin

    2017-02-01

    We investigate the filaments formed by the ultrashort laser pulses with different wavelengths of 400 nm, 586 nm and 800 nm propagating in argon. Numerical results show that, when the input power or the ratio of the input power to the critical power is given, the pulse with 400 nm wavelength has the largest on-axis intensity, as well as the narrowest filament and the most stable beam radius. These results indicate that the pulse with shorter wavelength is more suitable for the long-range propagation in argon.

  1. Wavelength routing beyond the standard graph coloring approach

    NASA Astrophysics Data System (ADS)

    Blankenhorn, Thomas

    2004-04-01

    When lightpaths are routed in the planning stage of transparent optical networks, the textbook approach is to use algorithms that try to minimize the overall number of wavelengths used in the . We demonstrate that this method cannot be expected to minimize actual costs when the marginal cost of instlling more wavelengths is a declining function of the number of wavelengths already installed, as is frequently the case. We further demonstrate how cost optimization can theoretically be improved with algorithms based on Prim"s algorithm. Finally, we test this theory with simulaion on a series of actual network topologies, which confirm the theoretical analysis.

  2. A high performance micro-dual-wavelength-spectrophotometer (MDWS).

    PubMed

    Schmidt, Werner

    2004-01-30

    The dual wavelength spectrophotometer (DWS) has proven to be the most sensitive device to monitor minute optical absorbance changes, which are inaccessible to conventional single or double beam spectrophotometers. The typical set ups, e.g. extensively used for Ca2+ or phytochrome measurements, are huge, expensive and cumbrous. Therefore, a novel high performance micro-dual-wavelength spectrophotometer (MDWS) was developed. It is miniaturized and no moving parts such as vibrational mirrors or rotating filter wheels involved. Its specifications are superior compared to the conventional set up being capable of detecting minute optical changes (reflection, absorbance, transmittance) at particular wavelengths.

  3. 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.

  4. 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.

  5. Short-wavelength infrared laser activates the auditory neurons: comparing the effect of 980 vs. 810 nm wavelength.

    PubMed

    Tian, Lan; Wang, Jingxuan; Wei, Ying; Lu, Jianren; Xu, Anting; Xia, Ming

    2017-02-01

    Research on auditory neural triggering by optical stimulus has been developed as an emerging technique to elicit the auditory neural response, which may provide an alternative method to the cochlear implants. However, most previous studies have been focused on using longer-wavelength near-infrared (>1800 nm) laser. The effect comparison of different laser wavelengths in short-wavelength infrared (SWIR) range on the auditory neural stimulation has not been previously explored. In this study, the pulsed 980- and 810-nm SWIR lasers were applied as optical stimuli to irradiate the auditory neurons in the cochlea of five deafened guinea pigs and the neural response under the two laser wavelengths was compared by recording the evoked optical auditory brainstem responses (OABRs). In addition, the effect of radiant exposure, laser pulse width, and threshold with the two laser wavelengths was further investigated and compared. The one-way analysis of variance (ANOVA) was used to analyze those data. Results showed that the OABR amplitude with the 980-nm laser is higher than the amplitude with the 810-nm laser under the same radiant exposure from 10 to 102 mJ/cm(2). And the laser stimulation of 980 nm wavelength has lower threshold radiant exposure than the 810 nm wavelength at varied pulse duration in 20-500 μs range. Moreover, the 810-nm laser has a wider optimized pulse duration range than the 980-nm laser for the auditory neural stimulation.

  6. A 158 {mu}m [C II] LINE SURVEY OF GALAXIES AT z {approx} 1-2: AN INDICATOR OF STAR FORMATION IN THE EARLY UNIVERSE

    SciTech Connect

    Stacey, G. J.; Hailey-Dunsheath, S.; Ferkinhoff, C.; Nikola, T.; Parshley, S. C.; Benford, D. J.; Staguhn, J. G.; Fiolet, N. E-mail: steve@mpe.mpg.d

    2010-12-01

    We have detected the 158 {mu}m [C II] line from 12 galaxies at z {approx} 1-2. This is the first survey of this important star formation tracer at redshifts covering the epoch of maximum star formation in the universe and quadruples the number of reported high-z [C II] detections. The line is very luminous, between <0.024% and 0.65% of the far-infrared (FIR) continuum luminosity of our sources, and arises from photodissociation regions on molecular cloud surfaces. An exception is PKS 0215+015, where half of the [C II] emission could arise from X-ray-dominated regions near the central active galactic nucleus (AGN). The L{sub [C{sub II}]}/L{sub FIR} ratio in our star formation-dominated systems is {approx}8 times larger than that of our AGN-dominated systems. Therefore this ratio selects for star formation-dominated systems. Furthermore, the L{sub [C{sub II}]}/L{sub FIR} and L{sub [C{sub II}]}/L{sub (CO(1-0))} ratios in our star-forming galaxies and nearby starburst galaxies are the same, so that luminous star-forming galaxies at earlier epochs (z {approx} 1-2) appear to be scaled-up versions of local starbursts entailing kiloparsec-scale starbursts. Most of the FIR and [C II] radiation from our AGN-dominated sample (excepting PKS 0215+015) also arises from kiloparsec-scale star formation, but with far-UV radiation fields {approx}8 times more intense than in our star formation-dominated sample. We speculate that the onset of AGN activity stimulates large-scale star formation activity within AGN-dominated systems. This idea is supported by the relatively strong [O III] line emission, indicating very young stars, that was recently observed in high-z composite AGN/starburst systems. Our results confirm the utility of the [C II] line, and in particular, the L{sub [C{sub II}]}/L{sub (FIR)} and L{sub [C{sub II}]}/L{sub CO(1-0)} ratios as tracers of star formation in galaxies at high redshifts.

  7. 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.

  8. 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.

  9. 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.

  10. Flaring Emission from Sagittarius A* at Millimeter Wavelengths

    NASA Astrophysics Data System (ADS)

    Li, J.; Shen, Z.; Miyazaki, A.; Huang, L.; Sault, R. J.; Miyoshi, M.; Tsuboi, M.; Tsutsumi, T.

    2011-05-01

    We present flaring emission observations from the Galactic Center compact radio source Sgr A* with the Australia Telescope Compact Array at mm wavelengths. Careful calibrations of both elevation-dependent and time-dependent gains have enabled us to establish the variability behavior of Sgr A*. Sgr A* was found to be very active, and several flares were detected at 3 mm wavelength during our observations from 2005 to 2008. On 2008 October 3, we detected flare emission quasi-simultaneously at 3 and 7 mm wavelengths, with the 3 mm flare leading 7 mm by about 1 hr. The observed time delay between 3 and 7 mm wavelength seems to support the expanding plasmon model.

  11. 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.

  12. Chalcogenide waveguide structure for dispersion in mid-infrared wavelength

    NASA Astrophysics Data System (ADS)

    Ashok, Nandam; Lak Lee, Yeung; Shin, WooJin

    2017-03-01

    We present a waveguide design with low dispersion in mid-infrared wavelengths. The design consists of slot-strip-slot structures horizontally, the strip structure is considered with high index and slot is considered with low index material. We show a dispersion of 0–350 ps/(km·nm) over a band width of 1375 nm, and the structure shows zero dispersions at 2512 and 3887 nm wavelength. The magnitude of dispersion can be fine-tuned by varying the waveguide parameters. Such a waveguide structure with low dispersion at mid-infrared wavelengths has a great potential for supercontinuum generation application. Apart this, we have also proposed dispersion compensation structure, the structure shows a high negative dispersion at 1510 nm wavelength. The structure should find application in the design of an integrated optic dispersion compensator for optical telecommunication and ultrafast waveguide lasers.

  13. Wavelength Tunability of Ion-Bombardment-Induced Ripples on Sapphire

    SciTech Connect

    Zhou,H.; Wang, Y.; Zhou, L.; Headrick, R.; Ozcan, A.; Wang, Y.; Ozaydin, G.; Ludwig, Jr., K.; Siddons, D.

    2007-01-01

    A study of ripple formation on sapphire surfaces by 300-2000 eV Ar{sup +} ion bombardment is presented. Surface characterization by in-situ synchrotron grazing incidence small angle x-ray scattering and ex-situ atomic force microscopy is performed in order to study the wavelength of ripples formed on sapphire (0001) surfaces. We find that the wavelength can be varied over a remarkably wide range -- nearly two orders of magnitude -- by changing the ion incidence angle. Within the linear theory regime, the ion induced viscous flow smoothing mechanism explains the general trends of the ripple wavelength at low temperature and incidence angles larger than 30{sup o}. In this model, relaxation is confined to a few nm thick damaged surface layer. The behavior at high temperature suggests relaxation by surface diffusion. However, strong smoothing is inferred from the observed ripple wavelength near normal incidence, which is not consistent with either surface diffusion or viscous flow relaxation.

  14. Lunar polarization studies at 3.1 mm wavelength

    NASA Technical Reports Server (NTRS)

    White, T. L.; Cogdell, J. R.

    1973-01-01

    Observations of the distribution of linearly polarized lunar thermal emission were made at a wavelength of 3.1 mm with The University of Texas 4.88 m parabolic reflector (0.042 deg HPBW). A shadow corrected, rough surface, thermal emission model for a homogeneous moon was least-squares-fitted to the polarization data. Results indicate an effective lunar dielectric constant of 1.34 plus or minus 0.04 with surface roughness characterized by a standard deviation of 17 (plus or minus 5) deg for surface slopes with a normal probability density, independent of lunar phase. A comparison of these results with published values at other wavelengths suggests that the effective lunar dielectric constant, as obtained by lunar emission measurements, decreases with decreasing wavelength of observation. This wavelength dependence may be interpreted in terms of an inhomogeneous surface and/or a surface that possesses intermediate scale surface roughness.

  15. Massively Sub-wavelength Guiding of Electromagnetic Waves

    PubMed Central

    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 1/600th 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. PMID:25510662

  16. 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.

  17. Metal-dielectric composites for beam splitting and far-field deep sub-wavelength resolution for visible wavelengths.

    PubMed

    Yan, Changchun; Zhang, Dao Hua; Zhang, Yuan; Li, Dongdong; Fiddy, M A

    2010-07-05

    We report beam splitting in a metamaterial composed of a silver-alumina composite covered by a layer of chromium containing one slit. By simulating distributions of energy flow in the metamaterial for H-polarized waves, we find that the beam splitting occurs when the width of the slit is shorter than the wavelength, which is conducive to making a beam splitter in sub-wavelength photonic devices. We also find that the metamaterial possesses deep sub-wavelength resolution capabilities in the far field when there are two slits and the central silver layer is at least 36 nm in thickness, which has potential applications in superresolution imaging.

  18. Optical phase conjugation of picosecond pulses at 1.06 mum in Sn(2)P(2)S(6):Te for wavefront correction in high-power Nd-doped amplifier systems.

    PubMed

    Bach, Tobias; Nawata, Kouji; Jazbinsek, Mojca; Omatsu, Takashige; Günter, Peter

    2010-01-04

    We report, for the first time to our knowledge, on picosecondpulse optical phase conjugation using photorefractive Sn(2)P(2)S(6) crystals. For 7.2-ps pulses at 1.06 mum, we have achieved phase-conjugate reflectivities of up to 45% with very fast build-up times, about 15 ms at an intensity of 23 W/cm(2) using Te-doped Sn(2)P(2)S(6). We furthermore demonstrate aberration-free 5 W optical output of 8-ps pulses at 1.06 mum from a side pumped Nd:YVO(4) amplifier using the Sn(2)P(2)S(6)-based phase-conjugate feedback.

  19. Optomechanical Light-Matter Interface with Optical Wavelength Conversion

    DTIC Science & Technology

    2015-07-21

    AFRL-AFOSR-VA-TR-2015-0240 DARPA) OPTOMECHANICAL LIGHT- MATTER INTERFACE WITH OPTICAL WAVELENGTH CONVERSION Hailin Wang University of Oregon, Eugene...2015 4. TITLE AND SUBTITLE (DARPA) OPTOMECHANICAL LIGHT- MATTER INTERFACE WITH OPTICAL WAVELENGTH CONVERSION 5a. CONTRACT NUMBER FA9550-10-1-0279 5b...of this program is to exploit this unique property to develop a light- matter interface that can map quantum states between two different optical

  20. Two-Wavelength Optical-Path-Difference Mapping

    NASA Technical Reports Server (NTRS)

    Manhart, Paul K.

    1990-01-01

    Proposed technique for measuring shapes and alignments of reflectors based on use of two-wavelength absolute-distance interferometer to generate optical-path-difference maps of reflecting or refracting surfaces. Facilitates such tasks as determining manufacturing and alignment errors of off-axis segment of large-aperture paraboloidal telescope mirror, or aligning all segments of such mirror. Suitable for use where reflecting surfaces highly aspherical, initial misalignments large, and/or surface errors exceed optical wavelengths.

  1. Multiple-wavelength Color Digital Holography for Monochromatic Image Reconstruction

    NASA Astrophysics Data System (ADS)

    Cheremkhin, P. A.; Shevkunov, I. A.; Petrov, N. V.

    In this paper, we consider the opposite problem, namely, using of color digital holograms simultaneously recorded on several wavelengths for the reconstruction of monochromatic images. Special feature of the procedure of monochromatic image reconstruction from the color hologram is the necessity of extracting information from separate spectral channels with a corresponding overlaying of obtained images to avoid mismatching of their spatial position caused by dependence of methods of numerical reconstruction from the laser wavelength.

  2. Multi-wavelength Observations of Microflares Near an Active Region

    NASA Astrophysics Data System (ADS)

    Bein, B.; Veronig, A.; Rybak, J.; Gömöry, P.; Berkebile-Stoiser, S.; Sütterlin, P.

    We study the multi-wavelength characteristics of a microflaring active region (AR 10898) near disc centre. The analysed data were from the 4^{th} of July 2006, and were recorded by DOT (Hα, Ca II H), RHESSI (X-rays), TRACE (EUV) and SOHO/MDI (magnetograms). The identified microflare events were studied with respect to their magnetic field configuration and their multi-wavelength time evolution.

  3. 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.

  4. Ultrafast laser-written dual-wavelength waveguide laser.

    PubMed

    Ams, Martin; Dekker, Peter; Marshall, Graham D; Withford, Michael J

    2012-03-15

    We report the performance of a dual-wavelength waveguide laser based on a phase-modulated sampled-grating architecture fabricated using the femtosecond laser direct-write technique. The waveguide laser was written in Yb-doped phosphate glass and had a narrow linewidth (<10 pm), high signal-to-noise ratio (>60 dB), 5 mW output power per channel, and wavelength separation of 10 nm.

  5. 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)

  6. Expanding plasma structure and its evolution toward long wavelengths

    SciTech Connect

    Sgro, A. G.; Peter Gary, S.; Lemons, D. S.

    1989-09-01

    The expansion of a plasma slab across an initially uniform magnetic field is simulated by the use of a two-dimensional electromagnetic hybrid (particle ions, fluid electrons of nonzero mass) computer code. The expanding plasma develops magnetic-field-aligned structure on time scales faster than an ion gyroperiod. Through the full duration of the /ital m//sub /ital i////ital m//sub /ital e// =100 simulation, the structure wavelength is well predicted by the wavelength at maximum growth rate from the linear Vlasov theory of the lower hybrid drift instability modified by deceleration. At /ital m//sub /ital i////ital m//sub /ital e// =400, the late time structure wavelength is about 1.5 times the early time value. At /ital m//sub /ital i////ital m//sub /ital e// =1836, the structure wavelength at early times is close to that corresponding to the maximum growth rate of linear theory, while at later times the structure wavelength becomes about twice as long as its early time value. These three results suggest that the ratio of the late time wavelength to the early time value gradually increases with /ital m//sub /ital i////ital m//sub /ital e//. Extrapolation of this scaling to larger /ital m//sub /ital i////ital m//sub /ital e// values is consistent with structure wavelengths observed in an expanding aluminum plasma experiment (J. Appl. Phys. J. /bold 20/, 157 (1981)), as well as the observed wavelength in the expanding barium plasma of the AMPTE magnetotail experiment (J. Geophys. Res. /bold 92/, 5777 (1987)).

  7. Far-field measurements of short-wavelength surface plasmons

    SciTech Connect

    Blau, Yochai; Gjonaj, Bergin; David, Asaf; Dolev, Shimon; Shterman, Doron; Bartal, Guy

    2015-03-23

    We present direct far-field measurements of short-wavelength surface plasmon polaritons (SPP) by conventional optics means. Plasmonic wavelength as short as 231 nm was observed for 532 nm illumination on a Ag−Si{sub 3}N{sub 4} platform, demonstrating the capability to characterize SPPs well below the optical diffraction limit. This is done by scaling a sub-wavelength interferometric pattern to a far-field resolvable periodicity. These subwavelength patterns are obtained by coupling light into counter-propagating SPP waves to create a standing-wave pattern of half the SPP wavelength periodicity. Such patterns are mapped by a scattering slit, tilted at an angle so as to increase the periodicity of the intensity pattern along it to more than the free-space wavelength, making it resolvable by diffraction limited optics. The simplicity of the method as well as its large dynamic range of measurable wavelengths make it an optimal technique to characterize the properties of plasmonic devices and high-index dielectric waveguides, to improve their design accuracy and enhance their functionality.

  8. Integration of both dense wavelength-division multiplexing and coarse wavelength-division multiplexing demultiplexer on one photonic crystal chip

    NASA Astrophysics Data System (ADS)

    Tian, Huiping; Shen, Guansheng; Liu, Weijia; Ji, Yuefeng

    2013-07-01

    An integrated model of photonic crystal (PC) demultiplexer that can be used to combine dense wavelength-division multiplexing (DWDM) and coarse wavelength-division multiplexing (CWDM) systems is first proposed. By applying the PC demultiplexer, dense channel spacing 0.8 nm and coarse channel spacing 20 nm are obtained at the same time. The transmission can be improved to nearly 90%, and the crosstalk can be decreased to less than -18 dB by enlarging the width of the bus waveguide. The total size of the device is 21×42 μm2. Four channels on one side of the demultiplexer can achieve DWDM in the wavelength range between 1575 and 1578 nm, and the other four channels on the other side can achieve CWDM in the wavelength range between 1490 and 1565 nm, respectively. The demonstrated demultiplexer can be applied in the future CWDM and DWDM system, and the architecture costs can be significantly reduced.

  9. Increased signals from short-wavelength-excited fluorescent molecules using sub-Ti:Sapphire wavelengths.

    PubMed

    Norris, G; Amor, R; Dempster, J; Amos, W B; McConnell, G

    2012-11-01

    We report the use of an all-solid-state ultrashort pulsed source specifically for two-photon microscopy at wavelengths shorter than those of the conventional Ti:Sapphire laser. Our approach involves sum-frequency mixing of the output from an optical parametric oscillator (λ= 1400-1640 nm) synchronously pumped by a Yb-doped fibre laser (λ= 1064 nm), with the residual pump radiation. This generated an fs-pulsed output tunable in the red spectral region (λ= 620-636 nm, ~150 mW, 405 fs, 80 MHz, M(2) ~ 1.3). We demonstrate the performance of our ultrashort pulsed system using fluorescently labelled and autofluorescent tissue, and compare with conventional Ti:Sapphire excitation. We observe a more than 3-fold increase in fluorescence signal intensity using our visible laser source in comparison with the Ti:Sapphire laser for two-photon excitation at equal illumination peak powers of 1.16 kW or less.

  10. Multi-wavelength multi-level optical storage

    NASA Astrophysics Data System (ADS)

    Wullert, John R., II

    Current digital information storage technologies offer rapid access and seemingly ever-increasing capacities. New storage techniques that improve the data rate of high-density storage technologies are attractive, particularly for cost-sensitive services such as video on demand. Wavelength multiplexing of optical information storage has the potential to increase storage capacity, density and data rate. This dissertation addresses the design, simulation and fabrication of a multi-wavelength, multi-level optical storage structure that has the potential to increase the capacity, density and data rate of optical storage. Multi-wavelength, multi-layer optical storage is a technique for storing data in many separate layers in a medium, where each layer responds to a unique optical wavelength. This approach builds on the strengths of current optical storage technologies and addresses some of their limitations. Multiple layers of storage increase the high storage density possible with optical techniques and the parallelism of wavelength multiplexing improves the relatively low data rate. Multi-wavelength, multi-level optical storage has been investigated theoretically and experimentally. The experimental results provide the first demonstration of optical storage using three wavelengths to read three separate layers of information. These read-only optical memories were based on dielectric mirrors of silicon dioxide, magnesium oxide and aluminum oxide. The layers were designed to be read with semiconductor lasers of 635, 780 and 980 nanometers. The prototype devices exhibited open margins between the on and off states for all eight combinations of the presence and absence of the three mirrors. Theoretical simulations were employed to assess the dynamic operation of multi-wavelength storage devices. Through systematic simulations, variations in the thickness and refractive index of the layers in the structure were identified as the primary noise mechanism and a critical

  11. Super sub-wavelength patterns in photon coincidence detection.

    PubMed

    Liu, Ruifeng; Zhang, Pei; Zhou, Yu; Gao, Hong; Li, Fuli

    2014-02-17

    High-precision measurements implemented with light are desired in all fields of science. However, light acts as a wave, and the Rayleigh criterion in classical optics yields a diffraction limit that prevents obtaining a resolution smaller than the wavelength. Sub-wavelength interference has potential application in lithography because it beats the classical Rayleigh resolution limit. Here, we carefully study second-order correlation theory to establish the physics behind sub-wavelength interference in photon coincidence detection. A Young's double slit experiment with pseudo-thermal light is performed to test the second-order correlation pattern. The results show that when two point detectors are scanned in different ways, super sub-wavelength interference patterns can be obtained. We then provide a theoretical explanation for this surprising result, and demonstrate that this explanation is also suitable for the results found for entangled light. Furthermore, we discuss the limitations of these types of super sub-wavelength interference patterns in quantum lithography.

  12. Super sub-wavelength patterns in photon coincidence detection

    NASA Astrophysics Data System (ADS)

    Liu, Ruifeng; Zhang, Pei; Zhou, Yu; Gao, Hong; Li, Fuli

    2014-02-01

    High-precision measurements implemented with light are desired in all fields of science. However, light acts as a wave, and the Rayleigh criterion in classical optics yields a diffraction limit that prevents obtaining a resolution smaller than the wavelength. Sub-wavelength interference has potential application in lithography because it beats the classical Rayleigh resolution limit. Here, we carefully study second-order correlation theory to establish the physics behind sub-wavelength interference in photon coincidence detection. A Young's double slit experiment with pseudo-thermal light is performed to test the second-order correlation pattern. The results show that when two point detectors are scanned in different ways, super sub-wavelength interference patterns can be obtained. We then provide a theoretical explanation for this surprising result, and demonstrate that this explanation is also suitable for the results found for entangled light. Furthermore, we discuss the limitations of these types of super sub-wavelength interference patterns in quantum lithography.

  13. Highly efficient entanglement swapping and teleportation at telecom wavelength.

    PubMed

    Jin, Rui-Bo; Takeoka, Masahiro; Takagi, Utako; Shimizu, Ryosuke; Sasaki, Masahide

    2015-03-20

    Entanglement swapping at telecom wavelengths is at the heart of quantum networking in optical fiber infrastructures. Although entanglement swapping has been demonstrated experimentally so far using various types of entangled photon sources both in near-infrared and telecom wavelength regions, the rate of swapping operation has been too low to be applied to practical quantum protocols, due to limited efficiency of entangled photon sources and photon detectors. Here we demonstrate drastic improvement of the efficiency at telecom wavelength by using two ultra-bright entangled photon sources and four highly efficient superconducting nanowire single photon detectors. We have attained a four-fold coincidence count rate of 108 counts per second, which is three orders higher than the previous experiments at telecom wavelengths. A raw (net) visibility in a Hong-Ou-Mandel interference between the two independent entangled sources was 73.3 ± 1.0% (85.1 ± 0.8%). We performed the teleportation and entanglement swapping, and obtained a fidelity of 76.3% in the swapping test. Our results on the coincidence count rates are comparable with the ones ever recorded in teleportation/swapping and multi-photon entanglement generation experiments at around 800 nm wavelengths. Our setup opens the way to practical implementation of device-independent quantum key distribution and its distance extension by the entanglement swapping as well as multi-photon entangled state generation in telecom band infrastructures with both space and fiber links.

  14. Effect of wavelength on cutaneous pigment using pulsed irradiation

    SciTech Connect

    Sherwood, K.A.; Murray, S.; Kurban, A.K.; Tan, O.T.

    1989-05-01

    Several reports have been published over the last two decades describing the successful removal of benign cutaneous pigmented lesions such as lentigines, cafe au lait macules' nevi, nevus of Ota, and lentigo maligna by a variety of lasers such as the excimer (351 nm), argon (488,514 nm), ruby (694 nm), Nd:YAG (1060 nm), and CO/sub 2/ (10,600 nm). Laser treatment has been applied to lesions with a range of pigment depths from superficial lentigines in the epidermis to the nevus of Ota in the reticular dermis. Widely divergent laser parameters of wavelength, pulse duration, energy density, and spotsizes have been used, but the laser parameters used to treat this range of lesions have been arbitrary, with little effort focused on defining optimal laser parameters for removal of each type. In this study, miniature black pig skin was exposed to five wavelengths (504, 590, 694, 720, and 750 nm) covering the absorption spectrum of melanin. At each wavelength, a range of energy densities was examined. Skin biopsies taken from laser-exposed sites were examined histologically in an attempt to establish whether optimal laser parameters exist for destroying pigment cells in skin. Of the five wavelengths examined, 504 nm produced the most pigment specific injury; this specificity being maintained even at the highest energy density of 7.0 J/cm2. Thus, for the destruction of melanin-containing cells in the epidermal compartment, 504 nm wavelength appears optimal.

  15. Chromosphere above sunspots as seen at millimeter wavelengths

    NASA Astrophysics Data System (ADS)

    Loukitcheva, Maria A.; Solanki, Sami K.; White, Stephen M.

    2011-08-01

    Millimeter emission is known to be a sensitive diagnostic of temperature and density in the solar chromosphere. In this work we use millimeter wave data to distinguish between various atmospheric models of sunspots, whose temperature structure in the upper photosphere and chromosphere has been the source of some controversy. From mm brightness simulations we expect a radio umbra to change its appearance from dark to bright (compared to the Quiet Sun) at a given wavelength in the millimeter spectrum (depending on the exact temperature in the model used). Thereby the millimeter brightness observed above an umbra at several wavelengths imposes strong constraints on temperature and density stratification of the sunspot atmosphere, in particular on the location and depth of the temperature minimum and the location of the transition region. Current mm/submm observational data suggest that brightness observed at short wavelengths is unexpectedly low compared to the most widely used sunspot models such as of Maltby et al. (1986). A successful model that is in agreement with millimeter umbral brightness should have an extended and deep temperature minimum (below 3000 K), such as in the models of Severino et al. (1994). However, we are not able to resolve the umbra cleanly with the presently available observations and better resolution as well as better wavelength coverage are needed for accurate diagnostics of umbral brightness at millimeter wavelengths. This adds one more scientific objective for the Atacama Large Millimeter/Submillimeter Array (ALMA).

  16. Sensitivity of heterointerfaces on emission wavelength of quantum cascade lasers

    NASA Astrophysics Data System (ADS)

    Wang, C. A.; Schwarz, B.; Siriani, D. F.; Connors, M. K.; Missaggia, L. J.; Calawa, D. R.; McNulty, D.; Akey, A.; Zheng, M. C.; Donnelly, J. P.; Mansuripur, T. S.; Capasso, F.

    2017-04-01

    The measured emission wavelengths of AlInAs/GaInAs/InP quantum cascade lasers (QCLs) grown by metal organic vapor phase epitaxy (MOVPE) have been reported to be 0.5-1 μm longer than the designed QCL wavelength. This work clarifies the origin of the red-shifted wavelength. It was found that AlInAs/GaInAs heterointerfaces are compositionally graded over 2.5-4.5 nm, and indium accumulates at the AlInAs-to-GaInAs interface. Thus, the as-grown QCLs are far from the ideal abrupt interfaces used in QCL modeling. When graded layers are incorporated in QCL band structure and wavefunction calculations, the emission wavelengths are red shifted. Furthermore, we demonstrate that QCLs with graded interfaces can be designed without compromising performance and show greatly improved correlation between designed and measured emission wavelength. QCLs were designed for emission between 7.5 and 8.5 μm. These structures were grown and wet-etched ridge devices were fabricated. The QCLs exhibit room temperature peak powers exceeding 900 mW and pulsed efficiencies of 8 to 10%.

  17. CANDELS MULTI-WAVELENGTH CATALOGS: SOURCE DETECTION AND PHOTOMETRY IN THE GOODS-SOUTH FIELD

    SciTech Connect

    Guo Yicheng; Barro, Guillermo; Faber, Sandra M.; Koo, David C.; Giavalisco, Mauro; Willner, S. P.; Ashby, Matthew L. N.; Donley, Jennifer L.; Fontana, Adriano; Galametz, Audrey; Grazian, Andrea; Kocevski, Dale D.; McGrath, Elizabeth J.; Peth, Michael; Salvato, Mara; Wuyts, Stijn; and others

    2013-08-15

    We present a UV to mid-infrared multi-wavelength catalog in the CANDELS/GOODS-S field, combining the newly obtained CANDELS HST/WFC3 F105W, F125W, and F160W data with existing public data. The catalog is based on source detection in the WFC3 F160W band. The F160W mosaic includes the data from CANDELS deep and wide observations as well as previous ERS and HUDF09 programs. The mosaic reaches a 5{sigma} limiting depth (within an aperture of radius 0.''17) of 27.4, 28.2, and 29.7 AB for CANDELS wide, deep, and HUDF regions, respectively. The catalog contains 34,930 sources with the representative 50% completeness reaching 25.9, 26.6, and 28.1 AB in the F160W band for the three regions. In addition to WFC3 bands, the catalog also includes data from UV (U band from both CTIO/MOSAIC and VLT/VIMOS), optical (HST/ACS F435W, F606W, F775W, F814W, and F850LP), and infrared (HST/WFC3 F098M, VLT/ISAAC Ks, VLT/HAWK-I Ks, and Spitzer/IRAC 3.6, 4.5, 5.8, 8.0 {mu}m) observations. The catalog is validated via stellar colors, comparison with other published catalogs, zero-point offsets determined from the best-fit templates of the spectral energy distribution of spectroscopically observed objects, and the accuracy of photometric redshifts. The catalog is able to detect unreddened star-forming (passive) galaxies with stellar mass of 10{sup 10} M{sub Sun} at a 50% completeness level to z {approx} 3.4 (2.8), 4.6 (3.2), and 7.0 (4.2) in the three regions. As an example of application, the catalog is used to select both star-forming and passive galaxies at z {approx} 2-4 via the Balmer break. It is also used to study the color-magnitude diagram of galaxies at 0 < z < 4.

  18. Long-Wavelength Infrared Views of Messier 81

    NASA Technical Reports Server (NTRS)

    2003-01-01

    The magnificent and dusty spiral arms of the nearby galaxy Messier 81 are highlighted in these NASA Spitzer Space Telescope images. 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 three-panel mosaic is a series of images obtained with the multiband imaging photometer for Spitzer. Thermal infrared emission at 24 microns (top), 70 microns (center) and 160 microns (bottom) is shown in the images. Note that the effective spatial resolution degrades as ones moves to longer wavelengths.

    At these wavelengths, Spitzer sees the dust, rather than the stars, within the disc of silicates and carbonaceous grains. It is well-mixed with gas, which is best seen at radio wavelengths, to form the essential ingredients for future star formation.

  19. In-vacuum long-wavelength macromolecular crystallography.

    PubMed

    Wagner, Armin; Duman, Ramona; Henderson, Keith; Mykhaylyk, Vitaliy

    2016-03-01

    Structure solution based on the weak anomalous signal from native (protein and DNA) crystals is increasingly being attempted as part of synchrotron experiments. Maximizing the measurable anomalous signal by collecting diffraction data at longer wavelengths presents a series of technical challenges caused by the increased absorption of X-rays and larger diffraction angles. A new beamline at Diamond Light Source has been built specifically for collecting data at wavelengths beyond the capability of other synchrotron macromolecular crystallography beamlines. Here, the theoretical considerations in support of the long-wavelength beamline are outlined and the in-vacuum design of the endstation is discussed, as well as other hardware features aimed at enhancing the accuracy of the diffraction data. The first commissioning results, representing the first in-vacuum protein structure solution, demonstrate the promising potential of the beamline.

  20. Wavelength dependence of the apparent diameter of retinal blood vessels

    NASA Astrophysics Data System (ADS)

    Park, Robert; Twietmeyer, Karen; Chipman, Russell; Beaudry, Neil; Salyer, David

    2005-04-01

    Imaging of retinal blood vessels may assist in the diagnosis and monitoring of diseases such as glaucoma, diabetic retinopathy, and hypertension. However, close examination reveals that the contrast and apparent diameter of vessels are dependent on the wavelength of the illuminating light. In this study multispectral images of large arteries and veins within enucleated swine eyes are obtained with a modified fundus camera by use of intravitreal illumination. The diameters of selected vessels are measured as a function of wavelength by cross-sectional analysis. A fixed scale with spectrally independent dimension is placed above the retina to isolate the chromatic effects of the imaging system and eye. Significant apparent differences between arterial and venous diameters are found, with larger diameters observed at shorter wavelengths. These differences are due primarily to spectral absorption in the cylindrical blood column.

  1. Effect of graphene on plasmonic metasurfaces at infrared wavelengths

    SciTech Connect

    Ogawa, Shinpei Fujisawa, Daisuke; Ueno, Masashi

    2013-11-15

    Significant enhancement of infrared transmittance by the presence of a graphene layer on a plasmonic metasurface (PLM) has been demonstrated. PLMs with different configurations were fabricated, and their transmittance with and without graphene was compared. Selective enhancement by graphene occurred at the plasmon resonance wavelength. The degree of enhancement was found to depend on the width of the gap between the periodic metal regions in the PLM. A maximum enhancement of ∼210% was achieved at a wavelength of 10 μm. The ability to achieve such a drastic increase in transmittance at the plasmon resonant wavelength is expected to lead to improvements in the performance of energy collecting devices and optical sensors.

  2. In-vacuum long-wavelength macromolecular crystallography

    PubMed Central

    Wagner, Armin; Duman, Ramona; Henderson, Keith; Mykhaylyk, Vitaliy

    2016-01-01

    Structure solution based on the weak anomalous signal from native (protein and DNA) crystals is increasingly being attempted as part of synchrotron experiments. Maximizing the measurable anomalous signal by collecting diffraction data at longer wavelengths presents a series of technical challenges caused by the increased absorption of X-rays and larger diffraction angles. A new beamline at Diamond Light Source has been built specifically for collecting data at wavelengths beyond the capability of other synchrotron macromolecular crystallography beamlines. Here, the theoretical considerations in support of the long-wavelength beamline are outlined and the in-vacuum design of the endstation is discussed, as well as other hardware features aimed at enhancing the accuracy of the diffraction data. The first commissioning results, representing the first in-vacuum protein structure solution, demonstrate the promising potential of the beamline. PMID:26960130

  3. Active Antenna Development for the Long Wavelength Array

    NASA Astrophysics Data System (ADS)

    Stewart, K. P.; Hicks, B. C.; Crane, P. C.; Ray, P. S.; Gross, C.; Polisensky, E. J.; Erickson, W. C.

    2005-12-01

    We are developing and testing active baluns and electrically short dipoles for possible use as the primary wideband receiving elements in the Long Wavelength Array (LWA) for HF-VHF radio astronomy. Several dipoles of various designs and dimensions have been built and tested. Their useful range occurs when the dipole arms are approximately 1/8 to one wavelength long and the feedpoint is less than 1/2 wavelength above ground. An eight-element NRL LWA Test Array (NLTA) interferometer has been built and fringes have been observed from the brightest celestial sources in the frequency range from 10 MHz to 50 MHz. The antenna temperatures vary from about 10% to 100% of the average brightness temperature of the galactic background. With these parameters it is easy to make the amplifier noise levels low enough that final system temperature is dominated by the galactic background.

  4. Method for separating FEL output beams from long wavelength radiation

    SciTech Connect

    Neil, George; Shinn, Michelle D.; Gubeli, Joseph

    2016-04-26

    A method for improving the output beam quality of a free electron laser (FEL) by reducing the amount of emission at wavelengths longer than the electron pulse length and reducing the amount of edge radiation. A mirror constructed of thermally conductive material and having an aperture therein is placed at an oblique angle with respect to the beam downstream of the bending magnet but before any sensitive use of the FEL beam. The aperture in the mirror is sized to deflect emission longer than the wavelength of the FEL output while having a minor impact on the FEL output beam. A properly sized aperture will enable the FEL radiation, which is coherent and generally at a much shorter wavelength than the bending radiations, to pass through the aperture mirror. The much higher divergence bending radiations will subsequently strike the aperture mirror and be reflected safely out of the way.

  5. Development of fast FBG interrogator with wavelength-swept laser

    NASA Astrophysics Data System (ADS)

    Yamaguchi, Tatsuya; Shinoda, Yukitaka

    2015-05-01

    The objective of this research is the construction of a structural health monitoring system that uses fiber Bragg grating (FBG) to determine the health of structures. We develop fast FBG interrogator for real-time measurement of the reflected wavelength of a multipoint FBG to monitor the broadband vibration of a structure. This FBG interrogator, which combines a wavelength-swept laser and a real-time measurement system is capable of measuring wavelength within a standard deviation of 2×10-3 nm or less. We have demonstrated that the FBG interrogator is able to measure vibration that has a resonance frequency of 440 Hz at intervals of 0.1 ms with a multipoint FBG.

  6. Effect of graphene on plasmonic metasurfaces at infrared wavelengths

    NASA Astrophysics Data System (ADS)

    Ogawa, Shinpei; Fujisawa, Daisuke; Ueno, Masashi

    2013-11-01

    Significant enhancement of infrared transmittance by the presence of a graphene layer on a plasmonic metasurface (PLM) has been demonstrated. PLMs with different configurations were fabricated, and their transmittance with and without graphene was compared. Selective enhancement by graphene occurred at the plasmon resonance wavelength. The degree of enhancement was found to depend on the width of the gap between the periodic metal regions in the PLM. A maximum enhancement of ˜210% was achieved at a wavelength of 10 μm. The ability to achieve such a drastic increase in transmittance at the plasmon resonant wavelength is expected to lead to improvements in the performance of energy collecting devices and optical sensors.

  7. Magic Wavelength for the Hydrogen 1S-2S Transition

    NASA Astrophysics Data System (ADS)

    Kawasaki, Akio

    2016-05-01

    The state of the art precision measurement of the transition frequencies of neutral atoms is performed with atoms trapped by the magic wavelength optical lattice that cancels the ac Stark shift of the transitions. Trapping with magic wavelength lattice is also expected to improve the precision of the hydrogen 1S-2S transition frequency, which so far has been measured only with the atomic beam. In this talk, I discuss the magic wavelength for the hydrogen 1S-2S transition, and the possibility of implementing the optical lattice trapping for hydrogen. Optical trapping of hydrogen also opens the way to perform magnetic field free spectroscopy of antihydrogen for the test of CPT theorem.

  8. Short Wavelength Seeding through Compression for Fee Electron Lasers

    SciTech Connect

    Qiang, Ji

    2010-03-29

    In this paper, we propose a seeding scheme that compresses an initial laser modulation in the longitudinal phase space of an electron beam 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 Cis the compression factor of the first bunch compressor. Using two lasers as energy chirpers, such a modulation compression scheme can generate kilo-Ampershort wavelength current modulation with significant bunching factor from an initial a few tens Amper current. This compression scheme can also be used togenerate a prebunched single atto-second short wavelength current modulation and prebunched two color, two atto-second modulations.

  9. Wavelength metrology with a color sensor integrated chip

    NASA Astrophysics Data System (ADS)

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

    2016-03-01

    We have developed a method of wavelength sensing using the TCS3414 from AMS, a color sensor developed for use in cell phones and consumer electronics. The sensor datasheet specifies 16 bits of precision and 200ppm/C° temperature dependence, which preliminary calculations showed might be sufficient for picometer level wavelength discrimination of narrow linewidth sources. We have successfully shown that this is possible by using internal etalon effects in addition to the filters' wavelength responses, and recently published our findings in OpticsExpress. Our device demonstrates sub picometer precision over short time periods, with about 10pm drift over a one month period. This method requires no moving or delicate optics, and has the potential to produce inexpensive and mechanically robust devices. Funded by Brigham Young University and NSF Grant Number PHY-1205736.

  10. Methemoglobin in blood as determined by double-wavelength spectrophotometry.

    PubMed

    Sakata, M; Yoshida, A; Haga, M

    1982-03-01

    We describe spectrophotometric determination of methemoglobin (Met-Hb) in blood by absorbance differences at two wavelengths (characteristic of the instrument used) in the 500-600 nm region. Blood is diluted 100- to 200-fold with a solution containing KCN and carbon monoxide to convert hemoglobin to carboxyhemoglobin and Met-Hb to cyanomethemoglobin (CN-Met-Hb). Carboxyhemoglobin has the same absorbance at the two wavelengths used, so that the differences in absorbance reflect only the CN-Met-Hb component. After measurement of absorbance differences, potassium ferricyanide is added to convert all hemoglobin derivatives to CN-Met-Hb; samples are then remeasured at the same wavelengths. The percentage of Met-Hb is determined from the ratio of the absorbance differences. Results agree satisfactorily with currently accepted procedures and with calculated theoretical results for mixtures of oxyhemoglobin, carboxyhemoglobin, and Met-Hb.

  11. Displacement measurement using a wavelength-phase-shifting grating interferometer.

    PubMed

    Lee, Ju-Yi; Jiang, Geng-An

    2013-10-21

    A grating interferometer based on the wavelength-modulated phase-shifting method for displacement measurements is proposed. A laser beam with sequential phase shifting can be accomplished using a wavelength-modulated light passing through an unequal-path-length optical configuration. The optical phase of the moving grating is measured by the wavelength-modulated phase-shifting technique and the proposed time-domain quadrature detection method. The displacement of the grating is determined by the grating interferometry theorem with the measured phase variation. Experimental results reveal that the proposed method can detect a displacement up to a large distance of 1 mm and displacement variation down to the nanometer range.

  12. The wavelength dependence of Martian atmospheric dust radiative properties

    NASA Technical Reports Server (NTRS)

    Pollack, J. B.; Ockert-Bell, M. E.; Arvidson, R.; Shepard, M.

    1993-01-01

    One of the key radiative agents in the atmosphere of Mars is the suspended dust particles. A new analysis of two data sets of the Martian atmosphere is being carried out in order to better evaluate the radiative properties of the atmospheric dust particles. The properties of interest are the size distribution, optical constants, and other radiative properties, such as the single-scattering albedo and phase function. Of prime importance is the wavelength dependence of these radiative properties throughout the visible and near-infrared wavelengths. Understanding the wavelength dependence of absorption and scattering characteristics will provide a good definition of the influence that the atmospheric dust has on heating of the atmosphere.

  13. A novel two-way wavelength division multiplexed fiber laser

    NASA Astrophysics Data System (ADS)

    Ke, Hung-Jen; Chiu, Jian-Lin; Chiang, Chia-Chin; Tsao, Shyh-Lin

    2006-08-01

    We use the fiber loop mirror to form a cavity in our laser system, and two 1.5 μm semiconductor optical amplifier (SOA) also be used as a gain material in the cavity. We analyze the lasing power, SMSR, L-I curve and the stability of our designed symmetric resonator laser with various driving current of the SOA. According to our measured results, we can find that the polarization states of our lasers are stable and the output side-mode suppression ration (SMSR) of our laser is large. We successfully designed a symmetric two-way multi-wavelength wavelength-division-multiplexed (WDM) resonator laser system. The multi-wavelength continuous-wave(CW) fiber laser by utilizing the Fabry-Perot resonance can be applied to PolSK fiber-optic communication systems.

  14. Multi-wavelength study of MGRO J2019+37

    NASA Astrophysics Data System (ADS)

    Hou, Chao; Chen, Song-Zhan; Yuan, Qiang; Cao, Zhen; He, Hui-Hai; Sheng, Xiang-Dong

    2014-08-01

    MGRO J2019+37, within the Cygnus region, is a bright extended source revealed by Milagro at 12-35 TeV. This source is almost as bright as the Crab Nebula in the northern sky, but is not confirmed by ARGO-YBJ around the TeV scale. Up to now, no obvious counterpart at low energy wavelengths has been found. Hence, MGRO J2019+37 is a rather mysterious object and its VHE γ-ray emission mechanism is worth investigating. In this paper, a brief summary of the multi-wavelength observations from radio to γ-rays is presented. All the available data from XMM-Newton and INTEGRAL at X-ray, and Fermi-LAT at γ-ray bands, are used to get constraints on its emission flux at low energy wavelengths. Then, its possible counterparts and the VHE emission mechanism are discussed.

  15. Do shorter wavelengths improve contrast in optical mammography?

    NASA Astrophysics Data System (ADS)

    Taroni, P.; Pifferi, A.; Torricelli, A.; Spinelli, L.; Danesini, G. M.; Cubeddu, R.

    2004-04-01

    The detection of tumours with time-resolved transmittance imaging relies essentially on blood absorption. Previous theoretical and phantom studies have shown that both contrast and spatial resolution of optical images are affected by the optical properties of the background medium, and high absorption and scattering are generally beneficial. Based on these observations, wavelengths shorter than presently used (680-780 nm) could be profitable for optical mammography. A study was thus performed analysing time-resolved transmittance images at 637, 656, 683 and 785 nm obtained from 26 patients bearing 16 tumours and 15 cysts. The optical contrast proved to increase upon decreasing wavelengths for the detection of cancers in late-gated intensity images, with higher gain in contrast for lesions of smaller size (<1.5 cm diameter). For cysts either a progressive increase or decrease in contrast with wavelength was observed in scattering images.

  16. Magic wavelengths, matrix elements, polarizabilities, and lifetimes of Cs

    NASA Astrophysics Data System (ADS)

    Safronova, M. S.; Safronova, U. I.; Clark, Charles W.

    2016-07-01

    Motivated by recent interest in their applications, we report a systematic study of Cs atomic properties calculated by a high-precision relativistic all-order method. Excitation energies, reduced matrix elements, transition rates, and lifetimes are determined for levels with principal quantum numbers n ≤12 and orbital angular momentum quantum numbers l ≤3 . Recommended values and estimates of uncertainties are provided for a number of electric-dipole transitions and the electric dipole polarizabilities of the n s , n p , and n d states. We also report a calculation of the electric quadrupole polarizability of the ground state. We display the dynamic polarizabilities of the 6 s and 7 p states for optical wavelengths between 1160 and 1800 nm and identify corresponding magic wavelengths for the 6 s -7 p1 /2 and 6 s -7 p3 /2 transitions. The values of relevant matrix elements needed for polarizability calculations at other wavelengths are provided.

  17. Residual zonal flows in tokamaks and stellarators at arbitrary wavelengths

    NASA Astrophysics Data System (ADS)

    Monreal, Pedro; Calvo, Iván; Sánchez, Edilberto; Parra, Félix I.; Bustos, Andrés; Könies, Axel; Kleiber, Ralf; Görler, Tobias

    2016-04-01

    In the linear collisionless limit, a zonal potential perturbation in a toroidal plasma relaxes, in general, to a non-zero residual value. Expressions for the residual value in tokamak and stellarator geometries, and for arbitrary wavelengths, are derived. These expressions involve averages over the lowest order particle trajectories, that typically cannot be evaluated analytically. In this work, an efficient numerical method for the evaluation of such expressions is reported. It is shown that this method is faster than direct gyrokinetic simulations performed with the Gene and EUTERPE codes. Calculations of the residual value in stellarators are provided for much shorter wavelengths than previously available in the literature. Electrons must be treated kinetically in stellarators because, unlike in tokamaks, kinetic electrons modify the residual value even at long wavelengths. This effect, that had already been predicted theoretically, is confirmed by gyrokinetic simulations.

  18. Use of Dual-wavelength Radar for Snow Parameter Estimates

    NASA Technical Reports Server (NTRS)

    Liao, Liang; Meneghini, Robert; Iguchi, Toshio; Detwiler, Andrew

    2005-01-01

    Use of dual-wavelength radar, with properly chosen wavelengths, will significantly lessen the ambiguities in the retrieval of microphysical properties of hydrometeors. In this paper, a dual-wavelength algorithm is described to estimate the characteristic parameters of the snow size distributions. An analysis of the computational results, made at X and Ka bands (T-39 airborne radar) and at S and X bands (CP-2 ground-based radar), indicates that valid estimates of the median volume diameter of snow particles, D(sub 0), should be possible if one of the two wavelengths of the radar operates in the non-Rayleigh scattering region. However, the accuracy may be affected to some extent if the shape factors of the Gamma function used for describing the particle distribution are chosen far from the true values or if cloud water attenuation is significant. To examine the validity and accuracy of the dual-wavelength radar algorithms, the algorithms are applied to the data taken from the Convective and Precipitation-Electrification Experiment (CaPE) in 1991, in which the dual-wavelength airborne radar was coordinated with in situ aircraft particle observations and ground-based radar measurements. Having carefully co-registered the data obtained from the different platforms, the airborne radar-derived size distributions are then compared with the in-situ measurements and ground-based radar. Good agreement is found for these comparisons despite the uncertainties resulting from mismatches of the sample volumes among the different sensors as well as spatial and temporal offsets.

  19. Continuous blood oxygen saturation detection with single-wavelength photoacoustics

    NASA Astrophysics Data System (ADS)

    Peng, Qiwen; Gao, Fei; Feng, Xiaohua; Zheng, Yuanjin

    2015-03-01

    Blood oxygen saturation (SO2) reflects the oxygenation level in blood transport and tissue. Previous studies have shown the capability of non-invasive quantitative measurements of SO2 by multi-wavelength photoacoustic (PA) spectroscopy for diagnosis of brain, tumor hemodynamics and other pathophysiological phenomena. However, those multi-wavelength methods require a tunable laser or multiple lasers which are relatively expensive and bulky for filed measurement environment and applications. Besides, the operation of multiple wavelengths, calibration procedures and data processing gets system complicated, which reduces the feasibility and flexibility for continuous real-time monitoring. Here we report a newly proposed method by combining PA and scattered light signals wherein imposing a hypothesis that scattering intensity is linear to the concentrations of oxygenated hemoglobin and deoxygenated hemoglobin weighed by blood scattering coefficients. A rigorous theoretical relationship between PA and scattering signals is thus established, making it possible that SO2 can be measured with only one excitation wavelength. To verify the theory basis, both dual-ink phantoms and fresh porcine blood sample have been employed in the experiments. The phantom experiment is able to quantify the concentration of mixed red-green ink that is in precise agreement with pre-set values. The ex vivo experiment with fresh porcine blood was conducted and the results of the proposed single-wavelength method achieved high accuracy of 1% - 4% errors. These demonstrated that the proposed single-wavelength SO2 detection is able to provide non-invasive, accurate measurement of blood oxygenation, and herein create potential for applying it to real clinical applications with low cost and high flexibility.

  20. Backward Raman amplification in the long-wavelength infrared

    NASA Astrophysics Data System (ADS)

    Johnson, L. A.; Gordon, D. F.; Palastro, J. P.; Hafizi, B.

    2017-03-01

    The wealth of work in backward Raman amplification in plasma has focused on the extreme intensity limit; however, backward Raman amplification may also provide an effective and practical mechanism for generating intense, broad bandwidth, long-wavelength infrared radiation (LWIR). An electromagnetic simulation coupled with a relativistic cold fluid plasma model is used to demonstrate the generation of picosecond pulses at a wavelength of 10 μm with terawatt powers through backward Raman amplification. The effects of collisional damping, Landau damping, pump depletion, and wave breaking are examined, as well as the resulting design considerations for an LWIR Raman amplifier.