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Sample records for 6g dye laser

  1. Seventeen psec pulses from a nitrogen laser-pumped short-cavity rhodamine 6G dye laser

    SciTech Connect

    Liesegang, G.W.

    1983-08-15

    We wish to report the generation of 17-psec pulses of 200-kW intensity from a nitrogen-pumped rhodamine 6G short-cavity dye laser. This dye laser has a cavity length of 120 ..mu..m and is axially pumped by the nitrogen laser. (AIP)

  2. Narrow bandwidth tuning of rhodamine 6G dye pumped by a XeCl excimer laser

    SciTech Connect

    Shangguan Cheng; Ling Ying-yi; Wang Yi-man; Dou Ai-rong; Huang Dan-hong

    1986-03-01

    In this paper the experimental study for narrow bandwidth tuning of ethylene glycol solution of rhodamine 6G pumped by a XeCl excimer laser is reported. The tunable range from 572.7 nm to 612.9 nm with linewidth of 0.004 nm has been obtained. The conversion efficiency is 16.0%. The experimental results of seven other dyes are also presented.

  3. Reciprocal passive mode locking of a rhodamine 6G dye laser and the Ar/sup +/ pump laser

    SciTech Connect

    Yasa, Z.A.; Amer, N.M.

    1981-02-01

    A rhodamine 6G dye laser, internally pumped within the extended cavity of an Ar/sup +/-ion laser, is mode locked when its cavity length is matched to half that of the pump laser: the 5145-A argon laser line is passively mode locked by the combination of the saturable absorption and the lasing action of the dye, which is in turn synchronously pumped and mode locked. Tunable (5650-5950-A)approx.10 psec pulses are generated, and the average output power is approx.80 mW.

  4. Reciprocal passive mode locking of a rhodamine 6G dye laser and the Ar+ pump laser

    SciTech Connect

    Yasa, Zafer A.; Amer, Nabil M.

    1981-02-01

    We report that a rhodamine 6G dye laser, internally pumped within the extended cavity of an Ar+-ion laser, is mode locked when its cavity length is matched to half that of the pump laser: the 5145-Å argon laser line is passively mode locked by the combination of the saturable absorption and the lasing action of the dye, which is in turn synchronously pumped and mode locked. Tunable (5650–5950-Å) ~10 psec pulses are generated, and the average output power is ~80 mW.

  5. Photodegradation and self-healing in a Rhodamine 6G dye and nanoparticle-doped polyurethane random laser

    NASA Astrophysics Data System (ADS)

    Anderson, Benjamin R.; Gunawidjaja, Ray; Eilers, Hergen

    2015-07-01

    One of the fundamental difficulties in implementing organic dyes in random lasers is irreversible photodegradation of the dye molecules, leading to loss of performance and the need to replace the dye. We report the observation of self-healing after photodegradation in a Rhodamine 6G dye and nanoparticle-doped polyurethane random laser. During irradiation, we observe two distinct temporal regions in which the random lasing emission first increases in intensity and redshifts, followed by further redshifting, spectral broadening, and decay in the emission intensity. After irradiation, the emission intensity is found to recover back to its peak value, while still being broadened and redshifted, which leads to the result of an enhancement of the spectrally integrated intensity. We also perform IR-VIS absorbance measurements and find that the results suggest that during irradiation, some of the dye molecules form dimers and trimers and that the polymer host is irreversibly damaged by photooxidation and Norrish type I photocleavage.

  6. Compression mechanism of subpicosecond pulses by malachite green dye in passively mode-locked rhodamine 6G/DODCI CW dye lasers

    SciTech Connect

    Watanabe, A.; Hara, M.; Kobayashi, H.; Takemura, H.; Tanaka, S.

    1983-04-01

    The pulse width compression effect of a malachite green (MG) dye upon subpicosecond pulses has been experimentally investigated in a CW passively mode-locked rhodamine 6G/DODCI dye laser. The pulse width reduces as MG concentration increases, and reaches 0.34 ps at 1.5 X 10/sup -6/ M. By adding the MG dye, good mode locking is achieved in a rather wide pumping-power range. A computer simulation of pulse growth has also been carried out by using simple rate equations, in which the fast-recovery component of loss due to the MG dye is taken into account. The simulated results can explain some experimental results qualitatively such as pulse width compression and pumping-power restriction. The pulse width compression results essentially from the fast recovery of cavity loss caused by the MG dye.

  7. Rhodamine 6G laser pumped by cathodoluminescence

    SciTech Connect

    Lisitsyn, V.M.; Lyakh, G.O.; Orlovskii, V.M.; Osipov, V.V.; Urbazaev, M.N.

    1984-08-01

    Cathodoluminescence from a CdS crystal, generated by the action of high-power short-duration electron beam pulses was used to pump a rhodamine 6G (R6G) laser. Measurements were made of the energy spectrum of the electrons in the beam exciting the CdS crystal, of the cathodoluminescence spectrum of CdS, of the absorption and emission spectra of the dye, and also of the time characteristics of the cathodoluminescence and of the dye laser radiation. When the electron beam incident on the crystal was characterized by a current of 500 A and duration 8 nsec at half-height, the radiation pulses emitted by R6G had an energy of approx.1 mJ and the efficiency of generation of these pulses was approx.0.3%. OFF

  8. The shape effect of Au particles on random laser action in disordered media of Rh6G dye doped with PMMA polymer

    NASA Astrophysics Data System (ADS)

    Yin, Jiajia; Feng, Guoying; Zhou, Shouhuan; Zhang, Hong; Wang, Shutong; Zhang, Hua

    2016-10-01

    Random laser actions in a disordered media based on polymethyl methacrylate (PMMA) polymer doped with Rh6G dye and Au nanoparticles have been demonstrated. It was observed that the shape of Au nanoparticles can tune the spectral central position of the random laser action. It was also seen that the shape of Au nanoparticles strongly affects the pump threshold. Comparing nanosphere- and nanorod-based systems, the nanorod-based one exhibited a lower threshold.

  9. Short pulse generation from a flashlamp-pumped rhodamine 6G ring dye laser using the colliding pulse mode-locking technique

    SciTech Connect

    Singh, S.

    1987-01-01

    The colliding pulse mode-locking (CPM) technique has been applied to a flashlamp-pumped rhodamine 6G dye laser to reliably generate pulses of <1.5 ps. Pulse evolution in the ring cavity has been studied by examining the pulse characteristics at various parts of the pulse train using a Photochron II streak camera. The measured pulse durations in the ring cavity were found to be detector-limited and were shorter than those generated in a linear cavity. The shortest pulses were observed to evolve toward the end of the --600-ns long mode-locked train.

  10. Spectroscopy and laser action of rhodamine 6G doped aluminosilicate xerogels

    SciTech Connect

    McKiernan, J.M.; Yamanaka, S.A.; Dunn, B.; Zink, J.I. )

    1990-07-26

    Rhodamine 6G (R6G) doped aluminosilicate glass synthesized by the sol-gel method exhibits laser action. Transparent 5 mm {times} 5 mm {times} 10 mm monoliths were used as cast in a simple laser cavity. This new material was pumped at rates of up to 25 Hz and was still active after as many as 40,000 pump pulses. Luminescence and free-running laser spectra are measured. The dependence of the R6G doped aluminosilicate dye laser output on the number of pump pulses and the pump pulse energy is discussed.

  11. Output characteristics of a laser utilizing rhodamine 6G in microporous glass

    SciTech Connect

    Al'tshuler, G.B.; Dul'neva, E.G.; Krylov, K.I.; Meshkovskii, I.K.; Urbanovich, V.S.

    1983-06-01

    A study was made of the lasing characteristics of new active media in the form of microporous glass containing a dye. The efficiency of conversion of the pump radiation, and the spatial and frequency spectra of the output radiation were determined for lasers with dispersive and nondispersive resonators and with active elements in the form of an ethanol solution of rhodamine 6G or microporous glass containing either rhodamine 6G or its ethanol solution. It was found that the use of active elements made of microporous glass and containing rhodamine 6G improved considerably the spatial characteristics of the output radiation compared with those obtained using liquid active media.

  12. Research of the quenched dye lasers pumped by excimer lasers

    SciTech Connect

    Xue Shaolin; Lou Qihong

    1996-12-31

    In this paper, the quenched dye lasers pumped by XeCl and KrF excimer lasers were investigated theoretically and experimentally. Dye laser pulses with duration of 0.8 ns for XeCl laser pumping and 2 ns for KrF laser pumping were obtained. The dye Rhodamine 6G dissolved in methyl was used as the active medium in the quenched dye laser. When the pump laser was KrF and the active medium was Coumarin 498 the quenched dye laser emitted pulse with duration of about 2 ns. The characteristics of the quenched dye laser was also investigated in detail.

  13. Study of photoproducts of Rhodamine 6G in ethanol upon powerful laser pumping

    SciTech Connect

    Batishche, S.A.; Malevich, N.A.; Mostovnikov, V.A.

    1995-04-01

    Absorption spectra of rhodamine 6G in ethanol solution are measured using, the technique of laser probing upon pumping by a doubled Nd {sup 3+}:YAG laser with pulse length{tau}{sub 01}{approx_equal}16ns. It is shown that, at the pumping energy density {ge}1.5 J/cm{sup 2}, short-lived ({tau} < 25 ns) and long-lived photoproducts formed in the dye solution, which absorbed in a wide spectral range, including the lasing region. The estimates show that the probability of rhodamine 6G transformation to the photoproduct upon three-step excitation at 532 nm achieves {approximately}2.5 X 10{sup -3}. It is noted that, in order to obtain reliable spectroscopic information using this technique, one should take into account the intense scattering of probing radiation by thermal noise gratings, which are formed due to self-diffraction of the pumping radiation into noise components.

  14. Feasibility of solar-pumped dye lasers

    NASA Technical Reports Server (NTRS)

    Lee, Ja H.; Kim, Kyung C.; Kim, Kyong H.

    1987-01-01

    Dye laser gains were measured at various pump-beam irradiances on a dye cell in order to evaluate the feasibility of solar pumping. Rhodamine 6G dye was considered as a candidate for the solar-pumped laser because of its high utilization of the solar spectrum and high quantum efficiency. Measurements show that a solar concentration of 20,000 is required to reach the threshold of the dye.

  15. Spectral and temporal features of the pumping of rhodamine 6G by radiation from a copper vapor laser

    SciTech Connect

    Soldatov, A.N.; Sukhanov, V.B.

    1983-01-01

    An experimental investigation was made of the influence of the relative delay time tau and of the intensity ratio R/sub 21/ of the spectral components emitted by a copper vapor laser on the energy and spectral characteristics of lasing in rhodamine 6G. For certain values of tau and P/sub 21/, lasing in the dye was disrupted. A clamping effect was discovered between the rhodamine 6G laser emission spectrum and the yellow line of the copper vapor laser. The results obtained were used to determine the parameters of an interference filter for suppressing the yellow line from the copper vapor laser, and this made it possible to raise the efficiency of conversion of the pump radiation into lasing in the dye.

  16. Spectral broadening in a microdroplet dye laser

    NASA Astrophysics Data System (ADS)

    Knospe, Anders G.; Kwok, Alfred S.

    2004-05-01

    We have observed broadening of the lasing spectrum of 60-μm diameter micrdroplet dye lasers. The spectral width of microdroplet dye lasers consisting of Rhodamine 6G or Pyrromethene 597 is essentially constant when water is used as a solvent but broaden by >30% at high input-laser intensities when ethanol is used as solvent. Spectral broadening is preceded by stimulated Raman scattering of ethanol in the microdroplets as the input-laser intensity increases.

  17. A sensitive fluorescence method for detection of E. Coli using rhodamine 6G dyeing.

    PubMed

    Wang, Yaohui; Jiang, Caina; Wen, Guiqing; Zhang, Xinghui; Luo, Yanghe; Qin, Aimiao; Liang, Aihui; Jiang, Zhiliang

    2016-06-01

    Negatively charged bacteria combined with positively charged alkaline dye rhodamine 6G (Rh6G) in NaH2 PO4 -Na2 HPO4 buffer solution pH 7.4, by electrostatic interaction. The dyed bacteria exhibited a strong fluorescence peak at 552 nm and fluorescence intensity was directly linear to Escherichia coli (E. coli), Bacillus subtilis (B. subtilis) and Staphylococcus aureus (S. aureus) concentrations in the range of 7.06 × 10(4) to 3.53 × 10(7) , 4.95 × 10(5) to 2.475 × 10(8) and 32.5 to 16250 colony forming unit/mL (cfu/mL) respectively, with detection limits of 3.2 × 10(4) cfu/mL E. coli, 2.3 × 10(5) cfu/mL B. subtilis and 16 cfu/mL S. aureus, respectively. Samples were cultured for 12 h, after which the linear detection range for E. coli was 2 to 88 cfu/mL. This simple, rapid and sensitive method was used for the analysis of water and drinking samples. Copyright © 2015 John Wiley & Sons, Ltd.

  18. Laser ablation of dyes

    NASA Astrophysics Data System (ADS)

    Späth, M.; Stuke, M.

    1992-01-01

    High density 50 μs pulses of the UV dyes PPF, POPOP and BBO and of two dyes in the visible region, Xanthen N92 and Fluorol 7GA were generated by laser ablation. Dye powders were pressed with 7800 kp/cm 2 in round pellets which were ablated by exposure to KrF excimer laser radiation (248 nm) at a fluence of 100 mJ/cm 2. The ablation cloud was optically activated with a XeCl excimer laser. Its fluorescence spectrum was measured and was identified as a dye vapour fluorescence spectrum by comparison to conventional dye solution and dye vapour spectra. The dye cloud is not deflected in an electric field (10 6 V/m). By changing the delay time between the ablation laser and the focused activation laser, the velocity distribution of the ablated dye was measured. Its maximum is at 600 m/s for PPF. Knowing the thickness of the ablated dye layer per shot (300 Å) and the size of the ablation cloud (pictures of a video camera), one can estimate the maximum density of the dye in the gas pulse to be 10 -5 mol/ l in the range of concentration of lasing dyes. However, no lasing was observed up to now.

  19. Laser based on dye-activated silica gel

    SciTech Connect

    Altshuler, G.B.; Bakhanov, V.A.; Dulneva, E.G.; Erofeev, A.V.; Mazurin, O.V.; Roskova, G.P.; Tsekhomskaya, T.S.

    1987-06-01

    Silica gel activated by a dye is used as a new laser medium. The lasin characteristics of rhodamine 6G in silica gel are reported. An important characteristic of the dye laser is its long service life, which is determined by the photostability of the dye in silic gel.(AIP)

  20. Study of laser emission losses in rhodamine 6G solutions under quasilongitudinal laser excitation

    SciTech Connect

    Aristov, A.V.; Eremenko, A.S.; Nikolaev, A.B.

    1986-08-01

    As a result of studies of the reciprocal of the quantum yield of stimulated laser emission as a function of the reciprocal of the useful loss factor, a quantitative dependence of induced losses in the pumping and lasing channels on the volume density of absorbed exciting radiation has been established. It is concluded from quantitative evidence that the margin of an appreciable increase in lasing efficiency for rhodamine 6G solutions consists in a decrease of the pumping-induced light scattering.

  1. Study of the spectral and angular characteristics of laser action by rhodamine 6G solutions in a short cavity

    SciTech Connect

    Smirnov, V.S.; Studenov, V.I.; Rozuvanova, V.A.

    1984-05-01

    An experimental and theoretical study has been made of the spectral and angular characteristics of a laser with an ethanol solution of rhodamine 6G, pumped with the second-harmonic radiation of an LTIPCh-6 laser, as a function of the spacing of a Fabry-Perot interferometer used as a cavity laser. It is shown experimentally that when the cavity is short, the radiation of the laser studied has a distinct spectral and angular structure which is determined by the length of the cavity and is independent of the reflectancies of the cavity mirrors, activator concentration, or power of the exciting radiation. Good agreement is shown to exist between the experimental and theoretical results. It is concluded that the character of formation of the spectral and angular radiation characteristics of a dye laser is determined almost entirely by the properties of the Fabry-Perot interferometer used as the cavity.

  2. Fanshaped superradiance of a dye laser

    SciTech Connect

    Wang, X.; Peng, G.

    1982-09-01

    The experimental apparatus used to achieve fan shaped superradiance of a dye laser by using second harmonics from a giant pulsed YAP:Nd(3+) laser oscillator-amplifier to pump Rhodamine 6G is described. The laser device employs a single 45 deg LiNbO3 electro-optical Q-switched yttrium aluminate laser as the oscillation stage, and after one stage of oscillation of yttrium aluminate laser amplification, it puts out a laser peak power of approximately 30 MW, with a repetition rate of once per second using LiLO3 (I type phase matching, theta m approximately 30 deg) outer cavity frequency doubling, it puts out 0.539 micrometer frequency doubled light, with a peak power of 1.8 MW and then uses the 0.539 micrometer frequency doubled light to pump Rhodamine 6G laser dye. The emission obtained assumes a fan shape which is planar.

  3. Oxazine laser dyes

    DOEpatents

    Hammond, Peter R.; Field, George F.

    1992-01-01

    New oxazine compounds useful as dye laser media in solution, are superiior to prior art materials. The oxazine dyes useful when pumped by the 578.2 nm copper line to operate in the 700-800 nm range are described by formula I ##STR1##

  4. Diode-pumped dye laser

    NASA Astrophysics Data System (ADS)

    Burdukova, O. A.; Gorbunkov, M. V.; Petukhov, V. A.; Semenov, M. A.

    2016-10-01

    This letter reports diode pumping for dye lasers. We offer a pulsed dye laser with an astigmatism-compensated three-mirror cavity and side pumping by blue laser diodes with 200 ns pulse duration. Eight dyes were tested. Four dyes provided a slope efficiency of more than 10% and the highest slope efficiency (18%) was obtained for laser dye Coumarin 540A in benzyl alcohol.

  5. Laser kinetic processes in dye mixtures

    SciTech Connect

    Lei Jie; Fu Honglang

    1988-11-01

    Radiation from rhodamine 6G+cresyl violet and rhodamine B+cresyl violet dye mixtures in ethyl alcohol pumped by N/sub 2/ laser light were studied. The rate constants of resonant transfer in the mixtures were determined. The radiative transfer processes are discussed.

  6. Laser dye technology

    SciTech Connect

    Hammond, P R

    1999-09-01

    The author has worked with laser dyes for a number of years. A first interest was in the Navy blue-green program where a flashlamp pumped dye laser was used as an underwater communication and detection device. It made use of the optical window of sea-water--blue for deep ocean, green for coastal water. A major activity however has been with the Atomic Vapor Laser Isotope Separation Program (AVLIS) at the Lawrence Livermore National Laboratory. The aim here has been enriching isotopes for the nuclear fuel cycle. The tunability of the dye laser is utilized to selectively excite one isotope in uranium vapor, and this isotope is collected electrostatically as shown in Figure 1. The interests in the AVLIS program have been in the near ultra-violet, violet, red and deep-red.

  7. Methods for reducing the divergence of lamp-excited rhodamine 6G solution lasers

    SciTech Connect

    Smirnov, V.S.

    1980-11-01

    Different methods for reducing the divergence of rhodamine 6G solution lasers with lamp pumping are studied experimentally. A reduction of divergence to 2--4 mrad is achieved. It is shown that some methods provide such low divergence for comparatively low losses of lasing energy.

  8. Tunable optofluidic distributed feedback dye lasers

    NASA Astrophysics Data System (ADS)

    Li, Zhenyu; Zhang, Zhaoyu; Emery, Teresa; Scherer, Axel; Psaltis, Demetri

    2006-08-01

    We demonstrated a continuously tunable optofluidic distributed feedback (DFB) dye laser on a monolithic poly(dimethylsiloxane) (PDMS) elastomer chip. The optical feedback was provided by a phase-shifted higher order Bragg grating embedded in the liquid core of a single mode buried channel waveguide. We achieved nearly 60nm continuously tunable output by mechanically varying the grating period with two dye molecules Rhodamine 6G (Rh6G) and Rhodamine 101 (Rh101). Single-mode operation was obtained with <0.1nm linewidth. Because of the higher order grating, a single laser, when operated with different dye solutions, can provide tunable output covering from near UV to near IR spectral region. The low pump threshold (< 1uJ) makes it possible to use a single high energy pulsed laser to pump hundreds of such lasers on a chip. An integrated array of five DFB dye lasers with different lasing wavelengths was also demonstrated. Such laser arrays make it possible to build highly parallel optical sensors on a chip. The laser chip is fully compatible with PDMS based soft microfluidics.

  9. Water soluble laser dyes

    DOEpatents

    Hammond, Peter R.; Feeman, James F.; Field, George F.

    1998-01-01

    Novel water soluble dyes of the formula I are provided ##STR1## wherein R.sup.1 and R.sup.4 are alkyl of 1 to 4 carbon atoms or hydrogen; or R.sup.1 -R.sup.2 or R.sup.2 -R.sup.4 form part of aliphatic heterocyclic rings; R.sup.2 is hydrogen or joined with R.sup.1 or R.sup.4 as described above; R.sup.3 is --(CH.sub.2).sub.m --SO.sub.3.sup.-, where m is 1 to 6; X is N, CH or ##STR2## where Y is 2 --SO.sub.3.sup.- ; Z is 3, 4, 5 or 6 --SO.sub.3.sup.-. The novel dyes are particularly useful as the active media in water solution dye lasers.

  10. Water soluble laser dyes

    DOEpatents

    Hammond, P.R.; Feeman, J.F.; Field, G.F.

    1998-08-11

    Novel water soluble dyes of the formula 1 are provided by the formula described in the paper wherein R{sup 1} and R{sup 4} are alkyl of 1 to 4 carbon atoms or hydrogen; or R{sup 1}--R{sup 2} or R{sup 2}--R{sup 4} form part of aliphatic heterocyclic rings; R{sup 2} is hydrogen or joined with R{sup 1} or R{sup 4} as described above; R{sup 3} is --(CH{sub 2}){sub m}--SO{sub 3}{sup {minus}}, where m is 1 to 6; X is N, CH or formula 2 given in paper where Y is 2 --SO{sub 3}{sup {minus}} ; Z is 3, 4, 5 or 6 --SO{sub 3}{sup {minus}}. The novel dyes are particularly useful as the active media in water solution dye lasers.

  11. Azacoumarin dye lasers

    DOEpatents

    Hammond, Peter R.; Atkins, Ronald L.; Henry, Ronald A.; Fletcher, Aaron N.

    1978-01-01

    A dye laser comprising a laser dye solution of a compound having the general structure: ##STR1## wherein at least one of the 5, 6 and 8 ring positions is occupied by a nitrogen atom in lieu of the corresponding CR group and X is OH, alkoxy, or amino including amino substituted by at least one of the following: alkyl, aryl, acyl, aracyl, a group which taken together with the nitrogen atom of the amino group forms a heterocyclic ring, or part of one or two 5 or 6 membered aliphatic heterocyclic rings attached to ring A at positions 6 or 8 or both depending on where the N in ring A is located. R.sub.3, R.sub.4, R.sub.5, R.sub.6 and R.sub.8 are hydrogen or other groups as defined below. The compounds lase in the blue-green to near ultraviolet region.

  12. Azaquinolone dye lasers

    DOEpatents

    Hammond, Peter R.; Atkins, Ronald L.; Henry, Ronald A.; Fletcher, Aaron N.

    1978-01-01

    A dye laser comprising a laser dye solution of a compound having the general structure: ##STR1## wherein at least one of the 5, 6 and 8 ring positions is occupied by a nitrogen atom in lieu of the corresponding CR group and X is OH, alkoxy, or amino including amino substituted by at least one of the following: alkyl, aryl, acyl, aracyl, a group which taken together with the nitrogen atom of the amino group forms a heterocyclic ring, or part of one or two 5 or 6 membered aliphatic heterocyclic rings attached to ring A at positions 6 or 8 or both depending on where the N in ring A is located. R.sub.1, R.sub.3, R.sub.4, R.sub.5, R.sub.6 and R.sub.8 are hydrogen or other groups as defined below. The compounds lase in the blue to near ultraviolet region.

  13. Single mode optofluidic distributed feedback dye laser

    NASA Astrophysics Data System (ADS)

    Li, Zhenyu; Zhang, Zhaoyu; Emery, Teresa; Scherer, Axel; Psaltis, Demetri

    2006-01-01

    Single frequency lasing from organic dye solutions on a monolithic poly(dimethylsiloxane) (PDMS) elastomer chip is demonstrated. The laser cavity consists of a single mode liquid core/PDMS cladding channel waveguide and a phase shifted 15th order distributed feedback (DFB) structure. A 1mM solution of Rhodamine 6G in a methanol and ethylene glycol mixture was used as the gain medium. Using 6 nanosecond 532nm Nd:YAG laser pulses as the pump light, we achieved threshold pump fluence of ~0.8mJ/cm2 and single-mode operation at pump levels up to ten times the threshold. This microfabricated dye laser provides a compact and inexpensive coherent light source for microfluidics and integrated optics covering from near UV to near IR spectral region.

  14. Dye system for dye laser applications

    SciTech Connect

    Hammond, P.R.

    1991-05-21

    This patent describes a dye of the DCM family, (2-methyl-6-(2-(1,2,3,4-tetrahydro-1-methyl-6-quinolinyl)ethenyl)-4H-pyran-4-ylidene)-propanedinitrile, dissolved in 2-phenoxyethanol, is non-mutagenic, stable and efficient, particularly in a pumped continuous wave laser system.

  15. Dye system for dye laser applications

    DOEpatents

    Hammond, Peter R.

    1991-01-01

    A dye of the DCM family, [2-methyl-6-[2-(1,2,3,4-tetrahydro-1-methyl-6-quinolinyl)ethenyl]-4H-pyran -4-ylidene]-propanedinitrile, dissolved in 2-phenoxyethanol, is non-mutagenic, stable and efficient, particularly in a pumped continuous wave laser system.

  16. Characteristics of a dye laser amplifier transversely pumped by copper vapor lasers with a two-dimensional calculation model

    SciTech Connect

    Sugiyama, A.; Nakayama, T.; Kato, M.; Maruyama, Y.

    1997-08-01

    A two-dimensional rate equation model, taking into consideration the transverse absorption loss of pump laser power, is proposed to evaluate the characteristics of a dye laser amplifier with a large input laser beam diameter pumped by high average power copper vapor lasers. The calculations are in good agreement with the measurements taken with a Rhodamine 6G dye, and the model can be used for evaluation of the dye concentration at any wavelength. {copyright} 1997 Optical Society of America

  17. Performance analysis and characterization of the Lumonics Inc. HyperDYE-300 laser-pumped dye laser. Final technical report

    SciTech Connect

    Taylor, T.S.; Davenport, W.E.; Ehrlich, J.J.

    1990-07-11

    The laser analyzed in this research, the Lumonics, Inc. HyperDYE-300 laser pumped dye laser, was procured via the FSTC D650 Program and was characterized in order to support the technology development of that program. The dye laser was pumped with a Neodymium:YAG q-switched laser and it utilized Rhodamine-6G in methanol. It was found to be tunable from about 545 nm to 590 nm and produced a maximum ouput energy of 56 percent of the pump beam energy. The analysis involved the measuring of optimum dye/solvent concentration, output energy versus tunability, optical efficiency versus tunability, temporal and spatial profiles, beam divergence, linewidth, and amplified spontaneous emission versus laser emission.

  18. Dye laser chain for laser isotope separation

    NASA Astrophysics Data System (ADS)

    Doizi, Denis; Jaraudias, Jean; Pochon, E.; Salvetat, G.

    1993-05-01

    Uranium enrichment by laser isotope separation uses a three step operation which requires four visible wavelengths to boost an individual U235 isotope from a low lying atomic energy level to an autoionizing state. The visible wavelengths are delivered by dye lasers pumped by copper vapor lasers (CVL). In this particular talk, a single dye chain consisting of a master oscillator and amplifier stages will be described and some of its performance given.

  19. High-repetition-rate high-power variable-bandwidth dye laser

    SciTech Connect

    Lavi, S.; Amit, M.; Bialolanker, G.; Miron, E.; Levin, L.A.

    1985-07-01

    An efficient high-repetition-rate dye laser is described which has a bandwidth that can be tailored to match typical atomic inhomogeneous linewidths. The dye laser is pumped by a 4-kHz 2--6 mJ/pulse copper vapor laser. The total efficiency of the dye laser (oscillator and amplifier) is 45% for rhodamine 6G and 30% for rhodamine B.

  20. Single mode pulsed dye laser oscillator

    DOEpatents

    Hackel, R.P.

    1992-11-24

    A single mode pulsed dye laser oscillator is disclosed. The dye laser oscillator provides for improved power efficiency by reducing the physical dimensions of the overall laser cavity, which improves frequency selection capability. 6 figs.

  1. Single mode pulsed dye laser oscillator

    DOEpatents

    Hackel, Richard P.

    1992-01-01

    A single mode pulsed dye laser oscillator is disclosed. The dye laser oscillator provides for improved power efficiency by reducing the physical dimensions of the overall laser cavity, which improves frequency selection capability.

  2. Dye-capped semiconductor nanoclusters. Excited state and photosensitization aspects of rhodamine 6G H-aggregates bound to SiO{sub 2} and SnO{sub 2} colloids

    SciTech Connect

    Nasr, C. |; Liu, D.; Kamat, P.V.; Hotchandani, S.

    1996-06-27

    SiO{sub 2} and SnO{sub 2} colloids are capped with a cationic dye, rhodamine 6G, by electrostatic interaction. The close packing of these dye molecules on the negatively charged SiO{sub 2} and SnO{sub 2} colloid results in the formation of H-aggregates. These aggregates are nonfluorescent but can inject electrons from the excited state into SnO{sub 2} colloids. The photophysical and photochemical properties of rhodamine-6G-aggregate on SiO{sub 2} and SnO{sub 2} colloids have been investigated using picosecond laser flash photolysis. Charge injection from the excited dye aggregate into SnO{sub 2} nanocrystallites occurs with a rate constant of 5.5 x 10{sup 9} s{sup -1}. The application of these dye aggregates in extending the photoresponse of nanocrystalline SnO{sup 2} film has been demonstrated by constructing a photoelectrochemical cell. A maximum incident photon-to-photocurrent efficiency of nearly 1% was observed for the photosensitized current generation. Fast reverse electron transfer between the injected electron and the cation radical of the dye aggregate is a limiting factor in maximizing the incident photon-to-photocurrent efficiency (IPCE). 65 refs., 11 figs.

  3. 29-fsec pulse generation from a linear-cavity synchronously pumped dye laser

    SciTech Connect

    Kubota, H.; Kurokawa, K.; Nakazawa, M.

    1988-09-01

    29-fsec optical pulses at a center wavelength of 615 nm have been generated from a linear-cavity synchronously pumped dye laser without using the colliding-pulse mode-locking technique. The laser consists of two dye jets (a gain jet and a saturable absorber jet) and a sequence of four Brewster-angled prisms. Kiton Red S is used as the laser dye instead of the conventional Rhodamine 6G.

  4. Precisely tunable, narrow-band pulsed dye laser

    SciTech Connect

    Bhatia, P.S.; Keto, J.W.

    1996-07-01

    A narrow-band, precisely tunable dye laser pumped by an injection-seeded YAG laser is described. The laser achieves an output of 100 mJ/pulse and 40{percent} efficiency when one uses Rhodamine 6G dyes. The output pulse is Gaussian both in time and spatial profile. The laser oscillator employs an intracavity {acute e}talon that is repetitively pressure scanned over one free spectral range while the grating successively steps to consecutive {acute e}talon modes. We pressure scanned the {acute e}talon under computer control using a bellows. Methods are described for calibrating the tuning elements for absolute precision. We demonstrated that the laser has an absolute precision of {plus_minus}0.4 pm over a 1.0-nm scan. This accuracy is achievable over the wavelength range of a dye. {copyright} {ital 1996 Optical Society of America.}

  5. Pneumatically tunable optofluidic dye laser

    NASA Astrophysics Data System (ADS)

    Song, Wuzhou; Psaltis, Demetri

    2010-02-01

    We presented a tunable optofluidic dye laser with integrated elastomeric air-gap etalon controlled by air pressure. The chip was fabricated with polydimethylsiloxane (PDMS) via replica molding. It comprises a liquid waveguide and microscale air-gap mirrors providing the feedback. The lasing wavelength is chosen by the interference between two parallel PDMS-air interfaces inside the internal tunable air-gap etalon, of which pneumatic tuning can be realized by inflating the air-gap etalon with compressed air. This dye laser exhibits a pumping threshold of 1.6 μJ/pulse, a lasing linewidth of 3 nm, and a tuning range of 14 nm.

  6. Laser induced fluorescence spectroscopy of various carbon nanostructures (GO, G and nanodiamond) in Rd6G solution

    PubMed Central

    Bavali, A.; Parvin, P.; Mortazavi, S. Z.; Nourazar, S. S.

    2015-01-01

    The effect of carbon nanostructures such as graphene (G), graphene oxide (GO) and nanodiamond (ND) on the spectral properties of Rhodamine 6G (Rd6G) emission due to the laser induced fluorescence (LIF) was investigated. It is shown that the addition of carbon nano- structures lead to sensible Red/Blue shifts which depend on the optical properties and surface functionality of nanoparticles. The current theories such as resonance energy transfer (RET), fluorescence quenching and photon propagation in scattering media support the experimental findings. Stern-Volmer curves for dynamic and static quenching of Rd6G molecules embedded with G, GO and nanodiamond are correlated with spectral shifts. Furthermore, time evolution of the spectral shift contributes to determine loading/release rates of fluorescent species with large S-parameter on the given nano-carriers. PMID:26137372

  7. High-power high-repetition-rate copper-vapor-pumped dye laser

    SciTech Connect

    Singh, S.; Dasgupta, K.; Kumar, S.; Manohar, K.G.; Nair, L.G.; Chatterjee, U.K. . Laser and Plasma Technology Div.)

    1994-06-01

    The design and development of an efficient high average power dye laser oscillator-amplifier system developed at the Laser and Plasma Technology Division, Bhabha Atomic Research Centre, is reported. The dye laser is pumped by a 6.5-kHz repetition rate copper vapor laser. The signal beam to the dye amplifier is obtained from an efficient narrow-band grazing incidence grating (GIG) dye laser oscillator incorporating a multiple prism beam expander. Amplifier extraction efficiency up to 40% was obtained in a single amplifier stage, using rhodamine 6G (Rh6G) in ethanol. The authors have also demonstrated simultaneous amplification of two laser beams at different wavelengths in the same dye amplifier cell.

  8. Triplet-extinction coefficients of some laser dyes. 1

    SciTech Connect

    Pavlopoulos, T.G.; Golich, D.J.

    1989-03-01

    For flashlamp-pumped dye lasers, the negative effect of triplet-state losses on laser action efficiency is well known. Oscilloscope traces of laser pulses showed that laser action diminishes much sooner than the flashlamp excitation pulse. This effect was attributed to the buildup of triplet-state dye molecules during the excitation from the flashlamp pulse. Triplet-extinction coefficients epsilon(T) were measured over the laser-action spectral region of Rhodamine 6G; Rhodamine B; Rhodamine 110; Fluorol-7GA; Coumarin 540A; Coumarin 522; Coumarin 1; Coumarin 120; 4,4'-diphenyl stilbene; and 2,7-bis(4-methoxy-phenyl)-9,9-dipropylfluorene. The different lines from an argon-ion cw laser were employed for excitation. McClure's method was used to obtain the triplet extinction coefficients Epsilon(T). The method requires the measurement of triplet optical densities OD(T) as a function of different cw laser-excitation intensities (powers) I(ex). The importance of triplet-state losses on dye-laser efficiency is reviewed. The laser action properties of the laser dyes studied are briefly discussed as they relate to the measured epsilon=(T) values.

  9. Triplet extinction coefficients of some laser dyes I

    SciTech Connect

    Pavlopoulos, T.G.; Golich, D.J.

    1988-07-15

    We measured the triplet extinction coefficients epsilon/sub T/ over the laser action spectral region of Rhodamine 6G; Rhodamine B; Rhodamine 110; Fluorol-7GA; Coumarin 540A; Coumarin 522; Coumarin 1; Coumarin 120; 4,4'-diphenyl stilbene; and 2,7-bis-(4-methoxy-phenyl)-9,9-dipropylfluorene. We employed the different lines from an argon ion cw laser for excitation. McClure's method was used to obtain the triplet extinction coefficients epsilon/sub T/. The method requires the measurement of triplet optical densities OD/sub T/ as a function of different cw laser excitation intensities (powers) I/sub ex/ . The importance of triplet-state losses on dye laser efficiency is reviewed. The laser action properties of the laser dyes we studied are briefly discussed as they relate to the measured epsilon/sub T/ values.

  10. Dye laser traveling wave amplifier

    NASA Technical Reports Server (NTRS)

    Davidson, F.; Hohman, J.

    1985-01-01

    Injection locking was applied to a cavity-dumped coaxial flashlamp pumped dye laser in an effort to obtain nanosecond duration pulses which have both high energy and narrow-linewidth. In the absence of an injected laser pulse, the cavity-dumped dye laser was capable of generating high energy (approx. 60mJ) nanosecond duration output pulses. These pulses, however, had a fixed center wavelength and were extremely broadband (approx. 6nm FWHM). Experimental investigations were performed to determine if the spectral properties of these outputs could be improved through the use of injection-locking techniques. A parametric study to determine the specific conditions under which the laser could be injection-locked was also carried out. Significant linewidth reduction to 0.0015nm) of the outputs was obtained through injection-locking but only at wavelengths near the peak lasing wavelength of the dye. It was found, however; that by inserting weakly dispersive tuning elements in the laser cavity, these narrow-linewidth outputs could be obtained over a wide (24nm) tuning range. Since the tuning elements had low insertion losses, the tunability of the output was obtained without sacrificing output pulse energy.

  11. High-power rhodamine 6G laser with an extended service life

    SciTech Connect

    Knyazev, B.A.; Lebedev, S.V.; Fokin, E.P.

    1983-02-01

    A laser was constructed in which rhodamine G dissolved in isopropyl alcohol was used as the active medium. It was pumped by a coaxial flashlamp and the output energy of the laser was up to 8 J. An investigation was made of the photochemical stability of rhodamine G solutions as a function of the spectral composition of the pump radiation. Optimal selection of the solvent and of a filter through which the pump radiation was passed, and the use of previously tested components ensured that the service life was superior to that of similar lasers; practically no maintenance was needed during operation. The operating characteristics of the laser and the dynamics of their changes over a period of three years of its use in applications were recorded. When the output energy was approx.5 J per pulse, the laser could emit 1.5 x 10/sup 3/ pulses without dismantling and replacement of the active medium and this represented an integrated irradiance of the active medium in excess of 2 kJ/cm/sup 3/.

  12. Grating cavity dual wavelength dye laser.

    PubMed

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

    2011-02-14

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

  13. Influence of thiourea on the emission characteristics of a laser based on an aqueous solution of rhodamine 6G

    SciTech Connect

    Viktorova, A.A.; Savikin, A.P.; Tsaregradskii, V.B.

    1983-08-01

    An investigation was made of the spectral (luminescence and lasing) characteristics of an aqueous solution of rhodamine 6G with an addition of thiourea. When the thiourea concentration in the solvent was > or =30%, the absorption and fluorescence spectra changed greatly, the lasing threshold decreased approximately fourfold, and the output power increased by an order of magnitude. The good thermooptical properties of water as a solvent, in combination with the disaggregation properties of thiourea, made it possible to realize (without circulation of the solution) a pulse-periodic lasing regime at a repetition frequency of < or approx. =50 Hz and with output radiation parameters typical of a laser with continuous circulation of an ethanol solution of rhodamine 6G.

  14. The aqueous-polyelectrolyte dye solution as an active laser medium

    SciTech Connect

    Akimov, A I; Saletskii, A M

    2000-11-30

    The spectral, luminescent, and lasing properties of aqueous solutions of a cationic dye rhodamine 6G with additions of anion polyelectrolytes - polyacrylic and polymethacrylic acids - are studied. It is found that the energy and spectral properties of lasing of these solutions depend on the ratio of concentrations of polyelectrolyte and molecules. It is also found that the lasing parameters of aqueous-polyelectrolyte dye solutions can be controlled by changing the structure of the molecular system. The variation in the structure of aqueous-polyelectrolyte dye solutions of rhodamine 6G resulted in an almost five-fold increase in the lasing efficiency compared to that in aqueous dye solutions. (lasers, active media)

  15. Solvent-free fluidic organic dye lasers.

    PubMed

    Choi, Eun Young; Mager, Loic; Cham, Tran Thi; Dorkenoo, Kokou D; Fort, Alain; Wu, Jeong Weon; Barsella, Alberto; Ribierre, Jean-Charles

    2013-05-01

    We report on the demonstration of liquid organic dye lasers based on 9-(2-ethylhexyl)carbazole (EHCz), so-called liquid carbazole, doped with green- and red-emitting laser dyes. Both waveguide and Fabry-Perot type microcavity fluidic organic dye lasers were prepared by capillary action under solvent-free conditions. Cascade Förster-type energy transfer processes from liquid carbazole to laser dyes were employed to achieve color-variable amplified spontaneous emission and lasing. Overall, this study provides the first step towards the development of solvent-free fluidic organic semiconducting lasers and demonstrates a new kind of optoelectronic applications for liquid organic semiconductors.

  16. Development of a single-mode dye laser pumped by a copper vapor laser

    NASA Astrophysics Data System (ADS)

    Arai, Yasushi; Niki, Hideaki; Adachi, Satoru; Takeda, Tetsuya; Yamanaka, Tatsuhiko; Yamanaka, Chiyoe

    1986-10-01

    An efficient high power single mode dye laser was developed for a study of uranium enrichment. The oscillation and amplification properties were studied experimentally and theoretically. The obtained band width was narrower than 100 MHz. When rhodamine 6 G chloride was used, the average output power and efficiency of the oscillator-amplifier system were 300 mW and 5%, respectively, at 575 nm for the total copper vapor laser pumping power of 4 W.

  17. Stimulated Raman scattering of laser dye mixtures dissolved in multiple scattering media

    SciTech Connect

    Yashchuk, V P; Komyshan, A O; Tikhonov, E A; Olkhovyk, L A

    2014-10-31

    Stimulated Raman scattering (SRS) of a mixture of rhodamine 6G and pyrromethene 605 laser dyes in vesicular films is studied. It is shown that a peculiar interaction of dyes occurs under conditions of multiple scattering of light from vesicles. This interaction manifests itself as SRS excitation of one of the dyes by random lasing of the other dye, provided that the random lasing spectrum overlaps the Stokes lines of the first dye. In addition, there is energy transfer between molecules of these dyes if their luminescence and absorption spectra overlap. The results obtained confirm that the mechanism of SRS from laser dyes in multiple scattering media is similar to that in coherent-active Raman spectroscopy. These results extend the possibility of determining the vibrational spectrum of dye molecules from their secondary radiation in these media. (nonlinear optical phenomena)

  18. The physics of dye laser amplifiers

    NASA Astrophysics Data System (ADS)

    Jensen, C. C.

    This paper describes a method for the complete analysis of the optical properties of a laser dye. The analysis uses direct measurements of the saturation intensities for absorption and emission. The complete analysis of an ultraviolet laser dye, 3,5,3,5-Tetra-t-butyl-p-sexiphenyl, demonstrates the power of the saturation analysis method. The dye TBS exhibits some unique optical properties which affect its emission wavelength range and photochemistry.

  19. Generation of microsecond laser pulses in polyurethane matrices doped with dyes

    SciTech Connect

    Nikolaev, S V; Pozhar, V V; Dzyubenko, M I

    2006-08-31

    Active laser elements based on polyurethane matrices doped with rhodamine 6G and oxazine 17 dyes are fabricated and tested. Lasing in the yellow-green and red spectral regions is obtained upon excitation of these matrices by a dye laser at 532 nm. The spectral and spatial-angular parameters of emission are studied. It is shown that these parameters are similar for polymer and liquid dye lasers. It is confirmed that pump radiation causes strong thermal distortions of active polymer media and the degree of influence of these distortions on lasing is demonstrated in experiments. The tuning of a laser based on a rhodamine 6G-doped polymer matrix is demonstrated in the range between 579 and 601 nm. (lasers)

  20. Solid state dye laser for medical applications

    NASA Astrophysics Data System (ADS)

    Aldag, Henry R.

    1994-06-01

    The development of solid state dye lasers could lead to a major breakthrough in the cost and compactness of a medical device. Advantages include: elimination of the flow system for the gain medium; ease with which to implement wavelength agility or the replacement of a degraded rod or sheet; and toxicity and flammability become a non-issue. Dye lasers have played a role in cardiology, dermatology, and urology. Of these cardiology is of interest to Palomar. The Palomar Model 3010 flashlamp-pumped dye laser medical device was used during phase 1 FDA clinical trials to break-up blood clots that cause heart attacks, a process known as coronary laser thrombolysis. It is the objective of this research and development effort to produce solid matrix lasers that will replace liquid dye lasers in these medical specialties.

  1. Dye lasers. Citations from the NTIS data base

    NASA Astrophysics Data System (ADS)

    Cavagnaro, D. M.

    1980-08-01

    Studies on dye laser theory, design, components, optical systems, and frequency range are presented in approximately 96 citations. Abstracts on lasing dyes, pumping, tuning, excitation, molecular structure, and modulation are included. Studies on dye laser use in spectroscopy are covered.

  2. Degradation of a textile dye, Rhodamine 6G (Rh6G), by heterogeneous sonophotoFenton process in the presence of Fe-containing TiO2 catalysts.

    PubMed

    Demir, Nazlı; Gündüz, Gönül; Dükkancı, Meral

    2015-03-01

    In this study, degradation of Rhodamine 6G (Rh6G) was investigated with ultrasound-assisted heterogeneous photoFenton process by iron-containing TiO2 catalysts. The catalysts were prepared by incipient wetness impregnation method and characterized by XRD, SEM, FT-IR, nitrogen adsorption, and ICP-AES measurements. Almost complete color removal (99.9 %) was achieved after a reaction time of 90 min while chemical oxygen demand (COD) could be removed by 24 % only with the 1 wt% iron-containing TiO2 catalyst. Initial color removal after 15 min of reaction and total COD abatement after 90 min of reaction decreased with increasing calcination temperature of the catalyst from 573 to 973 K. This indicated that the catalytic activity of the catalyst depend on the percentage of anatase phase in the TiO2, which was decreased with increasing calcination temperature.

  3. Degradation of a textile dye, Rhodamine 6G (Rh6G), by heterogeneous sonophotoFenton process in the presence of Fe-containing TiO2 catalysts.

    PubMed

    Demir, Nazlı; Gündüz, Gönül; Dükkancı, Meral

    2015-03-01

    In this study, degradation of Rhodamine 6G (Rh6G) was investigated with ultrasound-assisted heterogeneous photoFenton process by iron-containing TiO2 catalysts. The catalysts were prepared by incipient wetness impregnation method and characterized by XRD, SEM, FT-IR, nitrogen adsorption, and ICP-AES measurements. Almost complete color removal (99.9 %) was achieved after a reaction time of 90 min while chemical oxygen demand (COD) could be removed by 24 % only with the 1 wt% iron-containing TiO2 catalyst. Initial color removal after 15 min of reaction and total COD abatement after 90 min of reaction decreased with increasing calcination temperature of the catalyst from 573 to 973 K. This indicated that the catalytic activity of the catalyst depend on the percentage of anatase phase in the TiO2, which was decreased with increasing calcination temperature. PMID:24756679

  4. High-repetition-rate, narrow-band dye lasers with water as a solvent for dyes

    NASA Astrophysics Data System (ADS)

    Ray, Alok K.; Sinha, Sucharita; Kundu, Soumitra; Kumar, Sasi; Nair, Sivagiriyal Karunakaran Sreenivasan; Pal, Tamal; Dasgupta, Kamalesh

    2002-03-01

    The performance of a copper vapor laser-pumped narrow-band dye laser in oscillator-amplifier configuration with water-based binary mixture solvents is described. Although oscillator efficiency in water-surfactant (sodium lauryl sulfate) solvent was comparable with that that employed pure ethanolic solvent, amplifier efficiency was found to be lower. Experiments that were carried out with vertically polarized pump beams and either horizontally or vertically polarized signal beams show that, in case of both the pump and signal having orthogonal polarization (horizontal) and same polarization (vertical), the extraction efficiency for both ethanolic and water-micelle media increased substantially from 15.7% to 18.5% and from 10% to 12.5%, respectively. However, the relative difference remained nearly the same, indicating that a slower orientational diffusion of excited dye molecules in a micellar medium is not responsible for a decrease in amplifier efficiency. Amplifier efficiency comparable with that containing ethanolic dye solutions could be obtained with a binary solvent that comprises a mixture of water and about 30% n-propanol. The performances of two efficient dyes, Rhodamine-6G and Kiton Red S, using water-based solvents were studied.

  5. Continuous-wave dye laser pumped by a high-pressure argon arc

    SciTech Connect

    Thiel, E.; Zander, C.; Drexhage, K.

    1988-11-01

    Continuous-wave operation of a Rhodamine 6G dye laser, incoherently pumped by a high-pressure argon arc, has been achieved. A special electrode design reduces melting of the electrode tips, and thus the arc provides the necessary brightness for periods of the order of hours.

  6. Dye laser amplifier including a dye cell contained within a support vessel

    DOEpatents

    Davin, J.

    1992-12-01

    A large (high flow rate) dye laser amplifier in which a continuous replenished supply of dye is excited by a first light beam, specifically a copper vapor laser beam, in order to amplify the intensity of a second different light beam, specifically a dye beam, passing through the dye is disclosed herein. This amplifier includes a dye cell defining a dye chamber through which a continuous stream of dye is caused to pass at a flow rate of greater than 30 gallons/minute at a static pressure greater than 150 pounds/square inch and a specifically designed support vessel for containing the dye cell. 6 figs.

  7. Dye laser amplifier including a dye cell contained within a support vessel

    DOEpatents

    Davin, James

    1992-01-01

    A large (high flow rate) dye laser amplifier in which a continous replenished supply of dye is excited by a first light beam, specifically a copper vapor laser beam, in order to amplify the intensity of a second different light beam, specifically a dye beam, passing through the dye is disclosed herein. This amplifier includes a dye cell defining a dye chamber through which a continuous stream of dye is caused to pass at a flow rate of greater than 30 gallons/minute at a static pressure greater than 150 pounds/square inch and a specifically designed support vessel for containing the dye cell.

  8. Characteristics of a Broadband Dye Laser Using Pyrromethene and Rhodamine Dyes

    NASA Technical Reports Server (NTRS)

    Tedder, Sarah A.; Danehy, Paul M.; Wheeler, Jeffrey L.

    2011-01-01

    A broadband dye laser pumped by a frequency-doubled Nd:YAG laser with a full-width half-maximum (FWHM) from 592 to 610 nm was created for the use in a dual-pump broadband CARS system called WIDECARS. The desired broadband dye laser was generated with a mixture of Pyrromethene dyes as an oscillator gain medium and a spectral selective optic in the oscillator cavity. A mixture of Rhodamine dyes were used in the amplifier dye cell. To create this laser a study was performed to characterize the spectral behavior of broadband dye lasers created with Rhodamine dyes 590, 610, and 640, Pyrromethene dyes 597 and 650 as well as mixture of these dyes.

  9. High Raman-to-fluorescence ratio of Rhodamine 6G excited with 532  nm laser wavelength using a closely packed, self-assembled monolayer of silver nanoparticles.

    PubMed

    Sadegh, N; Khadem, H; Tavassoli, S H

    2016-08-01

    A highly efficient Raman-to-fluorescence ratio of Rhodamine 6G is obtained by means of 532 nm laser wavelength, which is in close proximity of the dye's absorption maximum. Closely packed, gap-filled self-assembled monolayers of silver nanoparticles were produced to observe the Raman signals of Rhodamine 6G. Two mechanisms contribute to detect the Raman signals of the fluorescent sample: surface-enhanced Raman scattering (SERS) and nanomaterial surface energy transfer (NSET). Self-assembled monolayers of silver nanoparticles with different coverage densities and also those filled with probe molecules were prepared through variations of the substrate's immersion time in a nanoparticle solution and drying the substrate, respectively. Examination of the effects of these two factors on the plasmonic response and SERS efficiency of the substrate revealed that in a gap-filled dense coverage, near-field interactions dominate, which remarkably increase the Raman-to-fluorescence ratio (RFR). To have a perfect dense coverage, the efficient immersion time was obtained at about 48 h. Drying the substrates also caused further enhancement in RFR through filling interparticle spaces with dye molecules and, accordingly, an increase in NSET efficiency. PMID:27505398

  10. Nanoimprinted polymer photonic crystal dye lasers

    NASA Astrophysics Data System (ADS)

    Christiansen, Mads B.; Smith, Cameron L. C.; Buss, Thomas; Xiao, Sanshui; Mortensen, Niels A.; Kristensen, Anders

    2010-05-01

    Optically pumped polymer photonic crystal band-edge dye lasers are presented. The photonic crystal is a rectangular lattice providing laser feedback as well as an optical resonance for the pump light. The lasers are defined in a thin film of photodefinable Ormocore hybrid polymer, doped with the laser dye Pyrromethene 597. A compact frequency doubled Nd:YAG laser (352 nm, 5 ns pulses) is used to pump the lasers from above the chip. The laser devices are 450 nm thick slab waveguides with a rectangular lattice of 100 nm deep air holes imprinted into the surface. The 2-dimensional rectangular lattice is described by two orthogonal unit vectors of length a and b, defining the ΓP and ΓX directions. The frequency of the laser can be tuned via the lattice constant a (187 nm - 215 nm) while pump light is resonantly coupled into the laser from an angle (θ) depending on the lattice constant b (355 nm). The lasers are fabricated in parallel on a 10 cm diameter wafer by combined nanoimprint and photolithography (CNP). CNP relies on a UV transparent quartz nanoimprint stamp with an integrated metal shadow mask. In the CNP process the photonic crystal is formed by mechanical deformation (imprinting) while the larger features are defined by UV exposure through the combined mask/mold.

  11. Flashlamp-pumped submicrosecond dye laser

    SciTech Connect

    Trusov, A.K.; Trusov, K.K.

    1985-02-01

    A laser flashlamp pumping system having an input energy of 330 J and a pulse duration of approx.230 nsec was developed experimentally and tests were made using a solution of rhodamine 6G under lasing conditions. The maximum lasing energy was 1.1 J, the efficiency was 0.33%, the angle of divergence of the beam at half-energy in a planar resonator was 1.2--1.3 mrad, and the illumination of an ethanol solution of rhodamine 6G halved the output energy when the intensity was 170 kJ/liter.

  12. Determination of the rate constants of molecular processes regulating the level of induced absorption in a laser based on an aqueous-micellar solution of rhodamine 6G with lamp pumping

    SciTech Connect

    Levin, M.B.; Snegov, M.I.; Cherkasov, A.S.

    1987-03-01

    A method of determining the average lifetime tau of the products responsible for inverse induced absorption in aqueous--micellar solutions of rhodamine 6G (R6G) on lamp pumping based on a comparison of threshold intensities of excitation (W/sub th/) in the resonators of a laser with a different Q is proposed. Using the value of tau found (0.2 ..mu..sec) and experimental data on the change in W/sub th/ with the concentration of cyclooctatetraene (COT) added to the solution the rate constant of quenching of the absorbing products by COT molecules (K/sub q/ = 2.6 x 10/sup 7/ M/sup -1/sec/sup -1/) was determined. In the assumption that the absorbing products are triplet dye molecules, the value of the rate constant of interconversion (K/sub 32/) of R6G into an aqueous--micellar solution (K/sub 32/ = 1.3 x 10/sup 7/ sec/sup -1/) was determined. A comparison was made of the values of the constants found with the corresponding values known from the literature.

  13. Mixed titanium, silicon, and aluminum oxide nanostructures as novel adsorbent for removal of rhodamine 6G and methylene blue as cationic dyes from aqueous solution.

    PubMed

    Pal, Umapada; Sandoval, Alberto; Madrid, Sergio Isaac Uribe; Corro, Grisel; Sharma, Vivek; Mohanty, Paritosh

    2016-11-01

    Mixed oxide nanoparticles containing Ti, Si, and Al of 8-15 nm size range were synthesized using a combined sol-gel - hydrothermal method. Effects of composition on the structure, morphology, and optical properties of the nanoparticles were studied using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), microRaman spectroscopy, and diffuse reflectance spectroscopy (DRS). Dye removal abilities of the nanoparticles from aqueous solutions were tested for different cationic dyes. While all the mixed oxide nanoparticles revealed high and fast adsorption of cationic dyes, the particles containing Ti and Si turned out to be the best. The adsorption kinetics and equilibrium adsorption behavior of the adsorbate - adsorbent systems could be well described by pseudo-second-order kinetics and Langmuir isotherm model, respectively. Estimated thermodynamic parameters revealed the adsorption process is spontaneous, driven mainly by the electrostatic force between the cationic dye molecules and negative charge at nanoparticle surface. Highest dye adsorption capacity (162.96 mg MB/g) of the mixed oxide nanostructures containing Ti and Si is associated to their high specific surface area, and the presence of surface Si-O(δ-) groups, in addition to the hydroxyl groups of amorphous titania. Mixed oxide nanoparticles containing 75% Ti and 25% Si seen to be the most efficient adsorbents for removing cationic dye molecules from wastewater.

  14. Mixed titanium, silicon, and aluminum oxide nanostructures as novel adsorbent for removal of rhodamine 6G and methylene blue as cationic dyes from aqueous solution.

    PubMed

    Pal, Umapada; Sandoval, Alberto; Madrid, Sergio Isaac Uribe; Corro, Grisel; Sharma, Vivek; Mohanty, Paritosh

    2016-11-01

    Mixed oxide nanoparticles containing Ti, Si, and Al of 8-15 nm size range were synthesized using a combined sol-gel - hydrothermal method. Effects of composition on the structure, morphology, and optical properties of the nanoparticles were studied using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), microRaman spectroscopy, and diffuse reflectance spectroscopy (DRS). Dye removal abilities of the nanoparticles from aqueous solutions were tested for different cationic dyes. While all the mixed oxide nanoparticles revealed high and fast adsorption of cationic dyes, the particles containing Ti and Si turned out to be the best. The adsorption kinetics and equilibrium adsorption behavior of the adsorbate - adsorbent systems could be well described by pseudo-second-order kinetics and Langmuir isotherm model, respectively. Estimated thermodynamic parameters revealed the adsorption process is spontaneous, driven mainly by the electrostatic force between the cationic dye molecules and negative charge at nanoparticle surface. Highest dye adsorption capacity (162.96 mg MB/g) of the mixed oxide nanostructures containing Ti and Si is associated to their high specific surface area, and the presence of surface Si-O(δ-) groups, in addition to the hydroxyl groups of amorphous titania. Mixed oxide nanoparticles containing 75% Ti and 25% Si seen to be the most efficient adsorbents for removing cationic dye molecules from wastewater. PMID:27529381

  15. Experimental studies on output, spatial, and spectral characteristics of a microdroplet dye laser containing intralipid as a highly scattering medium

    SciTech Connect

    Taniguchi, Hiroshi; Tanosaki, Shinji; Tsujita, Kazuhiro; Inaba, Humio

    1996-11-01

    Lasing characteristics of Rhodamine 6G dye-doped microdroplets containing highly scattering fat emulsion Intralipid-10% are studied experimentally. Noteworthy findings are that well-defined lasing threshold can be observed and one order or more magnitude enhancement of emission intensity with suitable (optimum) conditions of the Intralipid mixing ratio, in comparison with original neat-dye lasing microdroplets. The authors present and discuss the measured results of input-output intensities for different dye concentrations and dye-Intralipid mixing ratios in this high-gain laser dye-soft scatterer system and microscope images of spatial distribution of light emission from both the microdroplets containing neat-dye and dye-Intralipid mixture. It was found that almost no-lasing neat-dye microdroplets, which have either much higher or much lower dye concentration, can achieve lasing by substituting suitably certain amounts of the Intralipid, causing multiple light scattering. Spectral measurements of lasing outputs from the Rhodamine 6G dye-Intralipid microdroplets show the tendency of the disappearance of the well-known mode structures, owing to the morphology-dependent resonances of this microspherical cavity inherent to the neat-dye microdroplets. It is their belief that the present results make this novel method of dye-Intralipid microsystem very attractive for a variety of future applications, including diagnostic tools for highly sensitive detection and identification of small quantity objects and species embedded or hidden in highly scattering media.

  16. Performance of an array of plasma pinches as a new optical pumping source for dye lasers

    SciTech Connect

    Rieger, H.; Kim, K.

    1983-11-01

    A new optical pumping source consisting of an array of plasma pinches in the hypocycloidal-pinch geometry is employed to pump a variety of dye lasers. A dye cuvette is inserted along the symmetry axis of the plasma device such that it may be surrounded by the plasma pinch. The light from the plasma pinch is very intense and rich in ultraviolet, which makes it an attractive optical pumping source for dye lasers, particularly in the blue-green spectral region. Control of the plasma fluorescence is achieved by the choice of gas, its fill pressure, and the capacitor bank voltage and its stored energy. The rise time of this ''plasma flashlamp'' depends mainly on the gas species and the fill pressure. Output energy of approx.2 mJ per cm/sup 3/ of lasing medium, or 2 kW/cm/sup 3/ for a 1-..mu..s laser pulse, is obtained from rhodamine 6G, coumarin 480, LD 490, and coumarin 504 dyes. That both the coumarin 480 and rhodamine 6G lasers have the comparable output power is a direct proof that the present optical pumping source is more efficient than the commercial xenon flashlamps in pumping lasers in the blue-green spectral region.

  17. Dye lasers. Citations from the NTIS data base

    NASA Astrophysics Data System (ADS)

    Cavagnaro, D. M.

    1980-08-01

    This bibliography covers studies on dye laser theory, design, components, optical systems, and frequency range. Abstracts on lasing dyes, pumping, tuning, excitation, molecular structure, and modulation are included. Studies on dye laser use in spectroscopy are covered. This updated bibliography contains 217 citations, none of which are new entries to the previous edition.

  18. Dye laser amplifier including a low turbulence, stagnation-free dye flow configuration

    DOEpatents

    Davin, James

    1992-01-01

    A large (high flow rate) dye laser amplifier in which a continuous replenished supply of dye is excited by a first light beam, specifically a copper vapor laser beam, in order to amplify the intensity of a second different light beam, specifically a dye beam, passing through the dye is disclosed herein. This amplifier includes a dye cell defining a dye chamber through which a continuous stream of dye is caused to pass at a flow rate of for example 30 gallons/minute, a specifically designed support vessel for containing the dye cell and a screen device for insuring that the dye stream passes into the dye cell in a substantially turbulent free, stagnation-free manner.

  19. Dye laser amplifier including a low turbulence, stagnation-free dye flow configuration

    DOEpatents

    Davin, J.

    1992-12-01

    A large (high flow rate) dye laser amplifier in which a continuous replenished supply of dye is excited by a first light beam, specifically a copper vapor laser beam, in order to amplify the intensity of a second different light beam, specifically a dye beam, passing through the dye is disclosed herein. This amplifier includes a dye cell defining a dye chamber through which a continuous stream of dye is caused to pass at a flow rate of for example 30 gallons/minute, a specifically designed support vessel for containing the dye cell and a screen device for insuring that the dye stream passes into the dye cell in a substantially turbulent free, stagnation-free manner. 9 figs.

  20. Second harmonic and sum frequency generation on dye-coated surfaces using collinear and non-collinear excitation geometries. [Rhodamine 6G monolayers on glass

    SciTech Connect

    Muenchausen, R.E.; Nguyen, D.C.; Keller, R.A.; Nogar, N.S.

    1986-01-01

    Doubly resonantly enhanced sum frequency generation from rhodamine 6G monolayers adsorbed on glass substates is compared with resonantly enhanced second harmonic generation using a collinear excitation geometry. Second harmonic and sum frequency generation with a non-collinear excitation geometry is also reported where spatial filtering of the non-collinear output is shown to increase the scattered light rejection by more than 4 orders of magnitude.

  1. Design and Construction of Simple, Nitrogen-Laser-Pumped, Tunable Dye Lasers

    ERIC Educational Resources Information Center

    Hilborn, Robert C.

    1978-01-01

    The basic physical principles of dye lasers are discussed and used to analyze the design and operation of tunable dye lasers pumped by pulsed nitrogen lasers. Details of the design and construction of these dye lasers are presented. Some simple demonstration experiments are described. (BB)

  2. Study of excitation transfer in laser dye mixtures by direct measurement of fluorescence lifetime

    NASA Technical Reports Server (NTRS)

    Lin, C.; Dienes, A.

    1973-01-01

    By directly measuring the donor fluorescence lifetime as a function of acceptor concentration in the laser dye mixture Rhodamine 6G-Cresyl violet, we found that the Stern-Volmer relation is obeyed, from which the rate of excitation transfer is determined. The experimental results indicate that the dominant mechanism responsible for the efficient excitation transfer is that of resonance transfer due to long range dipole-dipole interaction.

  3. Solid-state tunable lasers based on dye-doped sol-gel materials

    SciTech Connect

    Dunn, B.; Mackenzie, J.D.; Zink, J.I.; Stafsudd, O.M.

    1992-03-01

    The sol-gel process is a solution synthesis technique which provides a low temperature chemical route for the preparation of rigid transparent matrix materials. The luminescent organic dye molecules, rhodamine 6G and coumarin 540A have been incorporated, via the sol-gel method, into aluminosilicate and organically modified silicate host matrices. Synthesis, laser oscillation and photostability for these systems are reported. The improved photostability of these materials with respect to comparable polymeric host materials is discussed.

  4. Reconfigurable Solid-state Dye-doped Polymer Ring Resonator Lasers.

    PubMed

    Chandrahalim, Hengky; Fan, Xudong

    2015-01-01

    This paper presents wavelength configurable on-chip solid-state ring lasers fabricated by a single-mask standard lithography. The single- and coupled-ring resonator hosts were fabricated on a fused-silica wafer and filled with 3,3'-Diethyloxacarbocyanine iodide (CY3), Rhodamine 6G (R6G), and 3,3'-Diethylthiadicarbocyanine iodide (CY5)-doped polymer as the reconfigurable gain media. The recorded lasing threshold was ~220 nJ/mm(2) per pulse for the single-ring resonator laser with R6G, marking the lowest threshold shown by solid-state dye-doped polymer lasers fabricated with a standard lithography process on a chip. A single-mode lasing from a coupled-ring resonator system with the lasing threshold of ~360 nJ/mm(2) per pulse was also demonstrated through the Vernier effect. The renewability of the dye-doped polymer was examined by removing and redepositing the dye-doped polymer on the same resonator hosts for multiple cycles. We recorded consistent emissions from the devices for all trials, suggesting the feasibility of employing this technology for numerous photonic and biochemical sensing applications that entail for sustainable, reconfigurable, and low lasing threshold coherent light sources on a chip. PMID:26674508

  5. Reconfigurable Solid-state Dye-doped Polymer Ring Resonator Lasers

    PubMed Central

    Chandrahalim, Hengky; Fan, Xudong

    2015-01-01

    This paper presents wavelength configurable on-chip solid-state ring lasers fabricated by a single-mask standard lithography. The single- and coupled-ring resonator hosts were fabricated on a fused-silica wafer and filled with 3,3′-Diethyloxacarbocyanine iodide (CY3), Rhodamine 6G (R6G), and 3,3′-Diethylthiadicarbocyanine iodide (CY5)-doped polymer as the reconfigurable gain media. The recorded lasing threshold was ~220 nJ/mm2 per pulse for the single-ring resonator laser with R6G, marking the lowest threshold shown by solid-state dye-doped polymer lasers fabricated with a standard lithography process on a chip. A single-mode lasing from a coupled-ring resonator system with the lasing threshold of ~360 nJ/mm2 per pulse was also demonstrated through the Vernier effect. The renewability of the dye-doped polymer was examined by removing and redepositing the dye-doped polymer on the same resonator hosts for multiple cycles. We recorded consistent emissions from the devices for all trials, suggesting the feasibility of employing this technology for numerous photonic and biochemical sensing applications that entail for sustainable, reconfigurable, and low lasing threshold coherent light sources on a chip. PMID:26674508

  6. Extended emission wavelength of random dye lasers by exploiting radiative and non-radiative energy transfer

    NASA Astrophysics Data System (ADS)

    Wan Ismail, Wan Zakiah; Goldys, Ewa M.; Dawes, Judith M.

    2016-02-01

    We demonstrate long-wavelength operation (>700 nm) of random dye lasers (using a methylene blue dye) with the addition of rhodamine 6G and titania, enabled by radiative and non-radiative energy transfer. The pump energy is efficiently absorbed and transferred to the acceptors, to support lasing in random dye lasers in the near infrared. The optimum random laser performance with the highest emission intensity and the lowest lasing threshold was achieved for a concentration of methylene blue as the acceptor equal to 6× the concentration of rhodamine 6G (donor). Excessive levels of methylene blue increased the lasing threshold and broadened the methylene blue emission linewidth due to dye quenching from re-absorption. This is due to competition between the donor emission and energy transfer and between absorption loss and fluorescence quenching. The radiative and non-radiative energy transfer is analyzed as a function of the acceptor concentration and pump energy density, with consideration of the spectral overlap. The dependence of the radiative and non-radiative transfer efficiency on the acceptor concentration is obtained, and the energy transfer parameters, including the radiative and non-radiative energy transfer rate constants ( K R and K NR), are investigated using Stern-Volmer analysis. The analysis indicates that radiative energy transfer is the dominant energy transfer mechanism in this system.

  7. Continuous-wave organic dye lasers and methods

    SciTech Connect

    Shapira, Ofer; Chua, Song-Liang; Zhen, Bo; Lee, Jeongwon; Soljacic, Marin

    2014-09-16

    An organic dye laser produces a continuous-wave (cw) output without any moving parts (e.g., without using flowing dye streams or spinning discs of solid-state dye media to prevent photobleaching) and with a pump beam that is stationary with respect to the organic dye medium. The laser's resonant cavity, organic dye medium, and pump beam are configured to excite a lasing transition over a time scale longer than the associated decay lifetimes in the organic dye medium without photobleaching the organic dye medium. Because the organic dye medium does not photobleach when operating in this manner, it may be pumped continuously so as to emit a cw output beam. In some examples, operation in this manner lowers the lasing threshold (e.g., to only a few Watts per square centimeter), thereby facilitating electrical pumping for cw operation.

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

    DOEpatents

    Johnson, Steve A.; Seppala, Lynn G.

    1986-01-01

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

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

    DOEpatents

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

    1984-06-13

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

  10. Pressure-induced shifts of the fluorescence spectrum of rhodamine 6G in solution

    SciTech Connect

    Zhang, B.; Chandrasekhar, M.; Chandrasekhar, H.R.

    1985-09-01

    The effect of hydrostatic pressure on the fluorescence spectrum of rhodamine 6G dye in two different solutions is studied. The peak shifts to longer wavelengths with increasing pressure with a pressure coefficient of -29 and -19 cm/sup -1//kbar for ethanol and 4:1 methanol-ethanol solvents, respectively. Possible applications of increasing the tunability of dye lasers by pressure are discussed.

  11. Irradiation of Escherichia coli in the Visible Spectrum with a Tunable Organic-Dye Laser Energy Source

    PubMed Central

    Takahashi, Patrick K.; Toups, Harold J.; Greenberg, David B.; Dimopoullos, George T.; Rusoff, Louis L.

    1975-01-01

    Pulsed laser energy was shown to be effective in inhibiting the growth of Escherichia coli. The irradiation source was derived from a tunable organic-dye laser utilizing rhodamine 6G (590 ± 5 nm) solutions as lasing media. The organisms, suspended in nutrient broth, were irradiated both with and without an exogenous photosensitizer. One photosensitizer (toluidine blue) did not appreciably alter the inhibitory effect observed. In the presence of acridine orange, however, some additional growth occurred. PMID:1089163

  12. Passive mode locking of an energy transfer continuous-wave dye laser

    SciTech Connect

    French, P.M.W.; Taylor, J.R.

    1986-08-01

    The first passive mode locking of a continuous-wave energy transfer dye laser is reported. Using an argon ion laser-pumped mixture of rhodamine 6G and sulphur rhodamine 101 as the active medium, pulses of less than 500 fs duration have been generated over the spectral range 652-694 nm using two different saturable absorbers in a simple linear cavity without dispersion optimization. Pulses as short as 120 fs have been measured using standard second-harmonic generation autocorrelation techniques.

  13. Structural influence of the inorganic network in the laser performance of dye-doped hybrid materials

    NASA Astrophysics Data System (ADS)

    Costela, A.; García-Moreno, I.; García, O.; del Agua, D.; Sastre, R.

    2005-05-01

    We report a systematic study of the influence on the laser action of Rhodamine 6G (Rh6G) of the composition and structure of new hybrid matrices based on 2-hydroxyethyl methacrylate (HEMA) as organic monomer and different weight proportions of dimethyldiethoxysilane (DEOS) and tetraethoxysilane (TEOS) as inorganic part. We selected mixtures of di- and tetra-functionalized alkoxides trying to decrease, in a controlled way, the rigidity of the three-dimensional network by making use of the flexibility provided by the linear chains acting as a spacer of the inorganic domains. The organization of the molecular units in these nanomaterials was studied through a structural analysis by solid-state NMR. The different reactivity exhibited by di- and tetra-functionalized silanols generates a non-homogeneous tri-dimensional network. Thus, the laser performance in dye-doped hybrid materials is improved when the inorganic phase is composed of a unique alkoxide.

  14. Experimental and theoretical investigation of a multipass, plane mirror, femtosecond dye laser amplifier

    NASA Astrophysics Data System (ADS)

    Wittmann, M.; Penzkofer, A.; Gössl, G.

    1995-08-01

    Femtosecond pulses of a passive mode-locked Rhodamine-6G dye laser are amplified in a double-stage, three-pass, plane mirror, Sulforhodamine-101 amplifier system. Saturable filters (Schott glass RG645 and Malachite Green) are used to suppress amplified spontaneous emission. Input pulses of 110-fs duration are broadened to 240 fs in the amplifier system and recompressed to 75 fs in a prism-pair compressor. Using a 20-Hz Q-switched Nd:YAG pump laser of 50-mJ second-harmonic output energy, we obtained amplified and recompressed pulses of 180- mu J energy at 625 nm starting with 40-pJ input pulses. The small-signal amplification dynamics is studied numerically. Relevant gain dye and saturable filter parameters are derived. The influence of amplified spontaneous emission is analyzed.

  15. Random lasers from dye-doped chiral photonic crystal films

    NASA Astrophysics Data System (ADS)

    Huang, Yuhua; Zhou, Ying; Wu, Shin-Tson

    2007-02-01

    We have obtained a dye-doped chiral photonic crystal (PC) film with reflection band gap much wider than its original band gap without dye dopants by using multiple-step fabrication processes. Moreover, the dye-doped chiral PC films using our multiple-step fabrication processes exhibit many oscillations within the broadened reflection band gap. The abrupt change of the optical density of state (DOS) around the oscillations provides the possibility of generating laser emission when the dye-doped chiral PC film is pumped by a pulsed laser with wavelength in the absorption region of the laser dye. Based on this property, we demonstrated random lasers which exhibit different multiple-mode laser wavelength at different spatial positions. Different from the random lasers induced by the scattering mechanism, the random lasers from the dye-doped cholesteric polymer film exhibit Gaussian-like beam shape and specific propagation orientation which is normal to the cholesteric planar surface. It is foreseeable that a high efficiency and high power broadband laser can be generated using cholesteric polymer films.

  16. Continuous-wave dye lasers in the DCM region.

    PubMed

    Hammond, P; Cooke, D

    1992-11-20

    Laser dye DCM in an ethylene glycol solution is a favored medium for converting the argon-ion 488- and 514-nm pump lines to tunable radiation in the 600-730-nm region. However, the dye precipitates from solution, is a powerful mutagen, and the glycol solvent is hygroscopic. Replacement dyes in 3-phenyl-1- propanol or 2-phenoxyethanol, particularly the latter, are proposed.

  17. Continuous-wave dye lasers in the DCM region

    SciTech Connect

    Hammond, P.; Cooke, D. )

    1992-11-20

    Laser dye DCM in an ethylene glycol solution is a favored medium for converting the argon-ion 488- and 514-nm pump lines to tunable radiation in the 600--730-nm region. However, the dye precipitates from solution, is a powerful mutagen, and the glycol solvent is hygroscopic. Replacement dyes in 3-phenyl-1-propanol or 2-phenoxyethanol, particularly the latter, are proposed.

  18. Photoactive dye enhanced tissue ablation for endoscopic laser prostatectomy

    NASA Astrophysics Data System (ADS)

    Ahn, Minwoo; Nguyen, Trung Hau; Nguyen, Van Phuc; Oh, Junghwan; Kang, Hyun Wook

    2015-02-01

    Laser light has been widely used as a surgical tool to treat benign prostate hyperplasia with high laser power. The purpose of this study was to validate the feasibility of photoactive dye injection to enhance light absorption and eventually to facilitate tissue ablation with low laser power. The experiment was implemented on chicken breast due to minimal optical absorption Amaranth (AR), black dye (BD), hemoglobin powder (HP), and endoscopic marker (EM), were selected and tested in vitro with a customized 532-nm laser system with radiant exposure ranging from 0.9 to 3.9 J/cm2. Light absorbance and ablation threshold were measured with UV-VIS spectrometer and Probit analysis, respectively, and compared to feature the function of the injected dyes. Ablation performance with dye-injection was evaluated in light of radiant exposure, dye concentration, and number of injection. Higher light absorption by injected dyes led to lower ablation threshold as well as more efficient tissue removal in the order of AR, BD, HP, and EM. Regardless of the injected dyes, ablation efficiency principally increased with input parameter. Among the dyes, AR created the highest ablation rate of 44.2+/-0.2 μm/pulse due to higher absorbance and lower ablation threshold. Preliminary tests on canine prostate with a hydraulic injection system demonstrated that 80 W with dye injection yielded comparable ablation efficiency to 120 W with no injection, indicating 33 % reduced laser power with almost equivalent performance. In-depth comprehension on photoactive dye-enhanced tissue ablation can help accomplish efficient and safe laser treatment for BPH with low power application.

  19. Conversion of the luminescence of laser dyes in opal matrices to stimulated emission

    SciTech Connect

    Alimov, O K; Basiev, T T; Orlovskii, Yu V; Osiko, V V; Samoilovich, M I

    2008-07-31

    The luminescence and laser characteristics of a synthetic opal matrix filled with organic dyes are studied upon excitation by nanosecond laser pulses. The appearance of stimulated emission in a partially ordered scattering medium is investigated. It is shown that if the luminescence spectrum of a dye (oxazine-17) is located far outside the photonic bandgap of the opal matrix, stimulated emission along a preferential direction in the (111) plane is observed when pumping exceeds a threshold even without an external optical cavity. The stimulated emission spectrum is considerably narrower than the luminescence spectrum and consists of several narrow lines located within the dye luminescence band. If the luminescence spectrum of a dye (rhodamine 6G) overlaps with the photonic bandgap of the opal matrix, a different picture is observed. The loss of radiation in the matrix leads to the red shift of the luminescence spectrum, while the stimulated emission as in the case of oxazine-17 lies is observed within the luminescence band. (active media, lasers, and amplifiers)

  20. Two-photon excitation of dyes in a polymer matrix by femtosecond pulses from a Ti:sapphire laser

    SciTech Connect

    Meshalkin, Yu P; Myachin, A Yu; Bakhareva, S S; Svetlichnyi, Valerii A; Kopylova, T N; Reznichenko, A V; Dolotov, S M; Ponomarenko, E P

    2003-09-30

    Two-photon fluorescence was observed for 18 organic dyes in a polymethyl methacrylate (PMMA) matrix excited by a femtosecond Ti:sapphire laser. The product of the cross section for two-photon absorption by the quantum yield of fluorescence (two-photon fluorescence cross section) is estimated by comparing it with fluorescence of Rhodamine 6G in ethanol. Using this parameter, dyes are selected that exhibit the most intense fluorescence in PMMA and their concentrations in PMMA are optimised. Coumarin and rhodamine dyes in polymer matrices are proposed for using as visualisers of femtosecond radiation of a Ti:sapphire laser and as detectors in self-triggering systems. (active media. lasers)

  1. Flashlamp-excited dye laser therapy for treatment of cutaneous vascular lesions

    NASA Astrophysics Data System (ADS)

    Goldberg, David J.

    1990-06-01

    Flashlamp excited dye laser therapy represents an exciting new advance in the treatment of a variety of cutaneous vascular lesions. Portwine stains, angiomas and telangiectases can be treated in all age groups with this laser system. This paper will review the physics of flashlamp dye laser photothermolysis. The differences between argon laser photocoagulation and flashlamp excited dye laser therapy will be reviewed.

  2. Investigation of a pulsed dye laser under various pumping conditions

    SciTech Connect

    Nechaev, S.Y.

    1983-08-01

    An investigation was made of the influence of bilateral laser pumping in an almost longitudinal arrangement on the spectral and energy characteristics of a short-pulse laser utilizing rhodamine 6G. A considerable increase in efficiency over that for unilateral pumping was observed, together with a narrowing of the spectrum, in a dispersive resonator having a prism telescope and a grating.

  3. Passive apparatus for stabilizing a flashlamp-pumped dye laser

    SciTech Connect

    De Wilde, M.A.; Decker, L.J.

    1986-04-29

    A flash lamp pumped, dye laser apparatus is described which consists of a flash lamp and a liquid dye solution in a transparent compartment proximate to the flash lamp. The compartment is also connected to a tubular circulatory system for moving the liquid dye. The dye solution is activated by flashing of the lamp for lasing to emit light, the lamp and compartment enclosed in a cooling first water jacket, the jacket enclosing deionized water for cooling, an improved cooling system wherein the temperature of the deionized water and the liquid dye solution are maintained within 0.5/sup 0/C of one another, enabling the laser for pulsing at a stabilized 10 pulses per second rate.

  4. Self-scanning of a dye laser due to feedback from a BaTiO/sub 3/ phase-conjugate reflector

    SciTech Connect

    Whitten, W.B.; Ramsey, J.M.

    1984-02-01

    Feedback from a self-pumped BaTiO/sub 3/ phase-conjugate reflector into an untuned cw dye laser produces substantial line narrowing (4--6 GHz) and generates a recurrent wavelength sweep from the rhodamine 6G peak at 618 nm to as far as 644 nm.

  5. Kinetic peculiarities of rhodamine 6G photodegradation in polymethylmethacrylate

    SciTech Connect

    Mardaleishvili, I.R.; Anisimov, V.M.

    1986-10-01

    Dye-activated polymer matrices have found recently wide technological applications as active laser media. The kinetic mechanism for dye photodegradation has been studied in this work for polymethylmethacrylate (PMMA) activated by rhodamine 6G (R6G). It has been found that the dye molecules are not equivalent with respect to their stability to the light and the effective width of their distribution over this parameter depends on the photon energy acting on the system. For the short wavelength UV irradiation (lambda = 254 nm) the distribution is narrow and it widens with an increase in the excitation wavelength. Optically transparent PMMA films (molecular weight 160,000 and thickness ca.20 mum) have been used in the present work. The necessity of accounting for the kinetics and effectiveness of the relaxation processes leading to a change in the reactivity of the molecules added to the polymer matrix limit the applicability of the kinetic stabilization method. A detailed study of the relaxation processes has been carried out, where it has been demonstrated for a number of polymer matrices, including PMMA, that a relaxation of guest molecules, leading to an enhancement of their reactivity, is effective only at the temperatures close to T /SUB c/ of the polymer. For PMMA activated by R6G the dark incubation of the previously irradiated sample for 30 min at 90 C leads to a substantial increase in the further photodegradation process. This is due to the fact that the relaxation process leads to an increased fraction of the highly reactive molecules. Diagrams are included.

  6. Concentration quenching of rhodamine 6G fluorescence in the adsorbed state

    SciTech Connect

    Zemskii, V.I.; Meshkovskii, I.K.; Sokolov, I.A.

    1985-08-01

    Porous glass to which molecules of organic dyes have been added is a promising active solid medium for tunable lasers. The spectroluminescent characteristics of samples of porous glass activated with rhodamine 6G molecules have been studied. It is shown that molecules of rhodamine 6G adsorbed in porus glass retain their capacity for fluorescence with a high quantum yield. Fixation of rhodamine 6G molecules on the pore walls interferes with their association in the concentration range up to 10/sup 19/ cm/sup -3/. Concentration quenching of fluorescence is observed starting with a concentration of dye molecules of 5 x 10/sup 15/ cm/sup -3/; this is explained by inductive-resonance energy transfer between monomeric molecules under conditions of inhomogeneous broadening of the electronic spectra of the adsorbed molecules.

  7. Laser photolysis of fluorone dyes in a chitosan matrix

    SciTech Connect

    Slyusareva, E A; Sizykh, A G; Gerasimova, M A; Slabko, V V; Myslivets, S A

    2012-08-31

    Kinetics of laser-induced photobleaching of fluorone dyes (fluorescein, dibromofluorescein, eosin Y, erythrosin B, Rose Bengal) is studied in a chitosan matrix. For all dyes the bleaching kinetics at the intensities of laser radiation 0.7 - 11.9 W cm{sup -2} demonstrates quasi-monomolecular behaviour. The results are analysed using a kinetic model, based on the four-level (S{sub 0}, S{sub 1}, T{sub 1}, T{sub n}) scheme of the dye with chemically active triplet states taken into account. It is shown that the rate constants of the chemical reaction involving higher triplet states in the dyes studied amount to (3.9 - 18.6) Multiplication-Sign 10{sup 6} s{sup -1} and exceed the analogous values for the reaction involving the first lower triplet states by nine orders of magnitude. The rate of reaction involving the first triplet states appeared to be higher by one - two orders of magnitude than that in the case of higher triplet states involved because of low population of the latter. The possible mechanism of dye bleaching with participation of chitosan that consists in reduction of the dye to the leuco form by transfer of hydrogen from the chitosan matrix is discussed. (interaction of laser radiation with matter. laser plasmas)

  8. Effect of gold nanoparticles on the optical properties of Rhodamine 6G

    NASA Astrophysics Data System (ADS)

    Barzan, Mohammad; Hajiesmaeilbaigi, Fereshteh

    2016-05-01

    Gold nanoparticles are synthesized by the laser ablation method and characterized by transmission electron microscopy and UV-visible absorption spectroscopy. The absorption and emission spectra and powers of Rhodamine 6G in the absence and presence of 27 nm diameter gold nanoparticles were studied. Empirical measurements represented that presence of gold nanoparticles lead to decrease the fluorescence power and fluorescence quantum yield, and increase the absorbance and absorbed power of Rhodamine 6G. Also, Stern-Volmer quenching constant of dye in proximity of nanoparticles shows high value which implies efficient quenching of the dye fluorescence by gold nanoparticles. Fluorescence quantum yield, radiative and nonradiative decay rate of Rhodamine 6G-gold nanoparticles assembly, in parallel orientation, as a function of dye's dipole moment distance from gold nanoparticle's surface, based on Gersten-Nitzan model, are calculated. Calculations show variations of the fluorescence quenching is strongly depended on the distance between the dye molecules and the Nps' surface. Also, calculated radiative decay rate indicates good agreement with the experimental value, and results of the ratio of the nonradiative to the radiative decay rate of Rhodamine 6G-gold nanoparticles mixture show nonradiative energy transfer is better explained in terms of NSET rather than FRET mechanism.

  9. Preparation of 6-hydroxyindolines and their use for preparation of novel laser dyes

    DOEpatents

    Field, G.F.; Hammond, P.R.

    1993-10-26

    A novel method is described for the synthesis of 6-hydroxyindolines and new fluorescent dyes produced therefrom, which dyes are ring-constrained indoline-based rhodamine class dyes. These dyes have absorption and emission spectra which make them particularly useful in certain dye laser applications.

  10. Preparation of 6-hydroxyindolines and their use for preparation of novel laser dyes

    DOEpatents

    Field, George F.; Hammond, Peter R.

    1993-01-01

    A novel method for the synthesis of 6-hydroxyindolines and new fluorescent dyes produced therefrom, which dyes are ring-constrained indoline-based rhodamine class dyes. These dyes have absorption and emission spectra which make them particularly useful in certain dye laser applications.

  11. Tunable DFB lasers based on DNA-surfactant-dye complexes

    NASA Astrophysics Data System (ADS)

    Chida, Toshifumi; Kawabe, Yutaka

    2012-10-01

    We succeeded to observe fluorescence enhancement and tunable laser emission from spin coated films of DNAcetyltrimetylammonium (CTMA) complex doped with weakly fluorescent cyanine dyes, DiQC2(1) and DiQC2(3) which were optically excited by interfering two beams forming a induced dynamic grating. Wavelength tuning of the laser emission was achieved by varying the angle between the pumping beams determining the grating period on the film. Degradation processes of the dye-doped films of DNA complex and PMMA were investigated and compared by monitoring absorption spectra after continuous excitation with a pulsed laser. Roles of DNA for fluorescence enhancement and improved durability were confirmed for these cyanine dyes.

  12. Parameters of a dye laser with transverse pumping

    SciTech Connect

    Burakov, V.S.; Samson, A.M.; Zhukovskii, V.V.; Isaevich, A.V.

    1987-12-01

    The authors describe a new method for determining the excitation and output parameters of dye laser media under conditions of transverse optical pumping by laser radiation. The dye is modeled as a medium with two electron-vibrational levels. The method is based on the variation of the value of the distance on the mirror reflection coefficients of the resonator and on estimates of inactive or parasitic losses, the probability of exciting active dye molecules with the radiation incident on the front face of the cell, and the unsaturated gain coefficient of that output frequency. Experimental data are then derived for these conditions for a rhodamine 4C solution in ethanol. Pumping was done using a neodymium laser.

  13. Photonics of laser-excited symmetric cationic polymethine dyes

    SciTech Connect

    Svetlichnyi, Valerii A; Maier, G V; Lapin, I N; Kopylova, T N; Derevyanko, Nadezhda A; Ishchenko, Aleksandr A

    2007-02-28

    Efficient lasing is obtained in the visible and near-IR spectral regions in solutions of symmetric polymethine dyes of the indolenine series (indocyanines) pumped by the second harmonic of a Nd{sup 3+}:YAG laser at 532 nm and an exciplex XeCl* laser at 308 nm into the first (long-wavelength) and higher-lying electronic absorption bands. The quantum lasing efficiency upon UV excitation achieves 37%. It is shown that these dyes can also limit the radiation power of these lasers. Polymethine dyes limit especially efficiently the second-harmonic power, their attenuation factor for the radiation power density of 100 MW cm{sup -2} achieving 14. The nanosecond flash-photolysis study of transient absorption spectra showed that the radiation power is limited by the mechanism of reverse saturated singlet-singlet absorption. It is established that the limiting ability of polymethines strongly depends on their structure. (active media)

  14. High-efficiency pyrromethene doped solid-state dye lasers

    SciTech Connect

    Hermes, R.E. ); Allik, T.H.; Chandra, S. ); Hutchinson, J.A. )

    1993-08-16

    Successful laser oscillation of various pyrromethene dyes doped in a modified acrylic plastic has been achieved. Pumped with a frequency doubled Nd:YAG laser at 532 nm, a slope efficiency of 85% has been obtained from one of the dyes in plastic, with an output beam energy of 128 mJ. A useful lifetime of greater than 20 000 shots at 3.33 Hz with output energies above 30 mJ has been demonstrated, with only a 34% loss in the available output energy.

  15. Convenient Microscale Synthesis of a Coumarin Laser Dye Analog

    ERIC Educational Resources Information Center

    Aktoudianakis, Evangelos; Dicks, Andrew P.

    2006-01-01

    Coumarin (2H-1-benzopyran-2-one) and its derivatives constitute a fascinating class of organic substances that are utilized industrially in areas such as cosmetics, food preservatives, insecticides and fluorescent laser dyes. The product can be synthesized, purified, and characterized within two hours with benefits of microscale reactivity being…

  16. A comparison of the Cassegrain and other beam expanders in high-power pulsed dye lasers

    NASA Astrophysics Data System (ADS)

    Trebino, R.; Siegman, A. E.; Roller, J. P.

    1982-08-01

    Beiting and Smith (1979) introduced a pulsed dye laser cavity employing an on-axis reflective Cassegrain telescope in place of the refractive telescope beam expander used in the dye laser oscillator reported by Haensch (1972). The new design has the potential to overcome several drawbacks of the Haensch design. The characteristics of the Cassegrain dye laser are discussed, and a report is presented of some problems encountered in an attempt to achieve efficient high-power operation. Attention is given to amplified spontaneous emission (ASE) and alignment effects, and to a comparison of the Cassegrain dye laser with other commonly used pulsed dye laser designs. It is found that the Cassegrain dye laser has some advantages over the Haensch design. These advantages are mainly related to the larger possible magnification and, hence, better linewidth. But the Cassegrain dye laser retains also several drawbacks inherent in the Haensch model, including alignment difficulty, high cost, and ASE.

  17. Generation of picosecond pulses in a dye laser excited by radiation from an argon laser with passively locked modes

    SciTech Connect

    Vinogradova, A.A.; Krindach, D.P.; Nazarov, B.I.; Tsapenko, A.M.

    1980-01-01

    Passive locking of argon laser modes was used in generation of tunable picosecond pulses in a synchronously excited dye laser. An experimental study was made of the characteristics of the dye laser radiation as a function of the argon laser characteristics.

  18. Interface module for transverse energy input to dye laser modules

    DOEpatents

    English, R.E. Jr.; Johnson, S.A.

    1994-10-11

    An interface module for transverse energy input to dye laser modules is provided particularly for the purpose of delivering enhancing transverse energy beams in the form of illumination bar to the lasing zone of a dye laser device, in particular to a dye laser amplifier. The preferred interface module includes an optical fiber array having a plurality of optical fibers arrayed in a co-planar fashion with their distal ends receiving coherent laser energy from an enhancing laser source, and their proximal ends delivered into a relay structure. The proximal ends of the optical fibers are arrayed so as to be coplanar and to be aimed generally at a common point. The transverse energy beam array delivered from the optical fiber array is acted upon by an optical element array to produce an illumination bar which has a cross section in the form of a elongated rectangle at the position of the lasing window. The illumination bar is selected to have substantially uniform intensity throughout. 5 figs.

  19. Interface module for transverse energy input to dye laser modules

    DOEpatents

    English, Jr., Ronald E.; Johnson, Steve A.

    1994-01-01

    An interface module (10) for transverse energy input to dye laser modules is provided particularly for the purpose of delivering enhancing transverse energy beams (36) in the form of illumination bar (54) to the lasing zone (18) of a dye laser device, in particular to a dye laser amplifier (12). The preferred interface module (10) includes an optical fiber array (30) having a plurality of optical fibers (38) arrayed in a co-planar fashion with their distal ends (44) receiving coherent laser energy from an enhancing laser source (46), and their proximal ends (4) delivered into a relay structure (3). The proximal ends (42) of the optical fibers (38) are arrayed so as to be coplanar and to be aimed generally at a common point. The transverse energy beam array (36) delivered from the optical fiber array (30) is acted upon by an optical element array (34) to produce an illumination bar (54) which has a cross section in the form of a elongated rectangle at the position of the lasing window (18). The illumination bar (54) is selected to have substantially uniform intensity throughout.

  20. Dye-enhanced diode laser photocoagulation of choroidal neovascularizations

    NASA Astrophysics Data System (ADS)

    Klingbeil, Ulrich; Puliafito, Carmen A.; McCarthy, Dan; Reichel, Elias; Olk, Joseph; Lesiecki, Michael L.

    1994-06-01

    Dye-enhanced diode laser photocoagulation, using the dye indocyanine green (ICG), has shown some potential in the treatment of choroidal neovascularizations (CNV). A diode laser system was developed and optimized to emit at the absorption maximum of ICG. In a clinical study at two retinal centers, more than 70 patients, the majority of which had age-related macular degeneration, were treated. Eighteen cases with ill-defined subfoveal CNV were followed an average of 11 months after laser treatment. The results show success in resolving the CNV with an average long-term preservation of visual function equal to or superior to data provided by the Macular Photocoagulation Study for confluent burns of low intensity applied to the CNV. Details of the technique and discussion of the controversies inherent in such a treatment strategy will be presented.

  1. Ultraviolet single-frequency coupled optofluidic ring resonator dye laser.

    PubMed

    Tu, Xin; Wu, Xiang; Li, Ming; Liu, Liying; Xu, Lei

    2012-08-27

    Ultraviolet single-frequency lasing is realized in a coupled optofluidic ring resonator (COFRR) dye laser that consists of a thin-walled capillary microfluidic ring resonator and a cylindrical resonator. The whispering gallery modes (WGMs) in each resonator couple to each other and generate single-frequency laser emission. Single-frequency lasing occurs at 386.75 nm with a pump threshold of 5.9 μJ/mm. The side-mode-suppression ratio (SMSR) is about 20 dB. Moreover, the laser emits mainly in two directions, and each of them has a divergence of only 10.5°.

  2. Dye-triplet-state and singlet-oxygen quenching effects in solid state dye lasers

    NASA Astrophysics Data System (ADS)

    King, Terence A.; Ahmad, Mohammad; Gorman, Anthony; Hamblett, I.; Rahn, Mark D.

    2000-04-01

    The main photodegradation mechanisms of pyrromethene 567 are discussed, and the quantum efficiency of self-sensitized photo-oxidation, the predominant mechanism, was found to be 0.5% in aerated benzene-d6. Other degradation mechanisms do exist, but the high photostability of the dye in solid host media possibly implies that they are all diffusion controlled. Solid-state dye lasers based on pyrromethene 567 doped poly(methyl methacrylate) with an added singlet oxygen quencher 1,4-diazobicyclo [2,2,2] octane showed a lifetime of 550,000 pulses. A triplet quencher, perylene, provided no improvement. Singlet oxygen quenching is effective in the solid-state whereas triplet quenching is not, presumably due to the slower diffusion rate of dye molecules compared with oxygen.

  3. Experimental and theoretical studies of complex pulse evolutions in a passively mode-locked ring dye laser

    SciTech Connect

    Avramopoulos, H.; French, P.M.W.; Williams, J.A.R.; New, G.H.C.; Taylor, J.R. )

    1988-09-01

    The optimization of any femtosecond laser requires the various sources of frequency chirp to be taken into account. In particular, for a passively mode-locked CPM ring dye laser, the effects of group velocity dispersion and self-phase modulation arising from time-dependent absorption saturation and the optical Kerr effect must be considered. In this paper a detailed experimental and theoretical study has been made of the role of these parameters in a Rhodamine 110 CPM dye laser. Periodic pulse evolutions are observed, when both positive and negative frequency chirp are present, which are reminiscent of those governed by the nonlinear Schrodinger equation but which are, in fact, distinctly different. Similar results have been obtained with the standard Rhodamine 6G system and it is believed that the theoretical model is generally applicable to any passively mode-locked femtosecond dye laser. An important consequence of this work is that is permits the absolute value of the net group velocity dispersion in the laser cavity to be estimated.

  4. Synthesis, structure, and physical properties of hybrid nanocomposites for solid-state dye lasers.

    PubMed

    García-Moreno, I; Costela, A; Cuesta, A; García, O; del Agua, D; Sastre, R

    2005-11-24

    We report on the synthesis, structural characterization, physical properties, and lasing action of two organic dyes, Rhodamine 6G (Rh6G) and Pyrromethene 597 (PM597), incorporated into new hybrid organic-inorganic materials, where the organic component was either poly(2-hydroxyethyl-methacrylate) (PHEMA) or copolymers of HEMA with methyl methacrylate (MMA), and the inorganic counterpart consisted of silica derived from hydrolysis-condensation of methyltriethoxysilane (TRIEOS) in weight proportion of up to 30%. Lasing efficiencies of up 23% and high photostabilities, with no sign of degradation in the initial laser output after 100 000 pump pulses at 10 Hz, were demonstrated when pumping the samples transversely at 534 nm with 5.5 mJ/pulse. A direct relationship could be established between the structure of the hybrid materials, analyzed by solid-state NMR, and their laser behavior. An inorganic network dominated by di-/tri- substituted silicates in a proportion approximately 35:65, corresponding to samples of HEMA with 15 and 20 wt % proportion of TRIEOS, optimizes the lasing photostability. The thermal properties of these materials, together with the high homogeneity revealed by atomic force microscopy (AFM) images, even in compounds with high silica content, indicate their microstructure to be a continuous phase, corresponding to the polymer matrix, which "traps" the silica components at molecular level via covalent bonding, with few or no silica islands.

  5. Spectral properties of optical anisotropy induced by laser radiation in dye solutions

    SciTech Connect

    Pikulik, L G; Chernyavskii, V A; Grib, A F

    2000-06-30

    Spectral studies of induced quasi-crystal properties (which can be quantitatively characterised by the difference in the refractive indices of ordinary and extraordinary waves, {Delta}n=n{sub o}-n{sub e}) in Rhodamine 6G and Rhodamine 4C solutions in glycerine excited in the visible and UV ranges of the absorption spectrum are presented. It is demonstrated that the observed spectral dependences of {Delta}n of these dye solutions excited in the visible (long-wavelength) and UV (short-wavelength) ranges of the absorption spectrum can be interpreted in terms of an oscillator model of a molecule. The proposed method for the analysis of induced optical anisotropy in solutions of organic compounds allows the relative orientation of oscillators in a molecule and, thus, the relative orientation of electronic transitions in a molecule to be determined in a reliable way. (iv international conference on atom and molecular pulsed lasers (ampl'99))

  6. Tunable optofluidic dye laser with integrated air-gap etalon

    NASA Astrophysics Data System (ADS)

    Song, Wuzhou; Vasdekis, Andreas E.; Psaltis, Demetri

    2010-11-01

    In this work we demonstrate an integrated air-gap etalon that enables single wavelength operation and tuning ability for optofluidic dye laser. The integrated elastomeric air-gap etalon is controlled by air pressure. The chip was fabricated with polydimethylsiloxane (PDMS) via replica molding. It comprises a liquid waveguide and micro-scale air-gap mirrors providing the feedback. The lasing wavelength is chosen by the interference between two parallel PDMS-air interfaces inside the internal tunable air-gap etalon, of which pneumatic tuning can be realized by inflating the air-gap etalon with compressed air. This dye laser exhibits a pumping threshold of 1.6 μJ/pulse, a lasing linewidth of 3 nm and a tuning range of 14 nm.

  7. Absorption-polarization characteristics of rhodamine 6G and its base in poly(methyl methacrylate)

    SciTech Connect

    Prishchepov, A.S.; Nizamou, N.

    1986-01-01

    Results are presented of the measurement and analysis of the absorption-polarization characteristics of rhodamine 6G and the base of rhodamine 6G (BR6G) in polymeric films of poly(methylmethacrylate) (PMMA). The absorption spectrum of a PMMA film containing BR6G and the cationic dye in the monomeric and associated states are shown.

  8. High-definition color image in dye thermal transfer printing by laser heating

    NASA Astrophysics Data System (ADS)

    Kitamura, Takashi

    1999-12-01

    In laser thermal transfer printing using dye sublimation type medium, a high definition and continuous tone image can be obtained easily because the laser beam is focused to small spot and heat energy can be controlled by the pulse width modulation of laser light. The donor ink sheet is composed of the laser absorbing layer and sublimation dye layer. The tone reproduction was depend on the mixture ratio of dye to binder and thickness of ink layer. The four color ink sheets such as cyan, magenta, yellow and black were prepared for color printing image which have a high resolution and good continuous tone reproduction using sublimation dye transfer printing by laser heating.

  9. Electronic improvement of interferometric measurement of dye laser wavelengths

    NASA Astrophysics Data System (ADS)

    Mulders, J. J. L.; Steeman, P. A. M.; Kemper, A. H.; Steenhuysen, L. W. G.

    1985-08-01

    The wavelength of a dye laser beam has been determined with a Michelson interferometer with one moving mirror. The addition and design of a phase locked loop (PLL) to multiply the fringe frequency is discussed. Experimentally it appeared that the addition of a PLL has two main advantages: an improvement in the resolution of the system by a factor of ten, and an improvement in reproducibility due to the flywheel effect of the PLL.

  10. Raman-shifted dye laser for water vapor DIAL measurements.

    PubMed

    Grossmann, B E; Singh, U N; Higdon, N S; Cotnoir, L J; Wilkerson, T D; Browell, E V

    1987-05-01

    For improved DIAL measurements of water vapor in the upper troposphere or lower stratosphere, we have generated narrowband (~0.03-cm(-1)) laser radiation at 720- and 940-nm wavelengths by stimulated Raman scattering (SRS) using the narrow linewidth (~0.02-cm(-1)) output of a Nd:YAG-pumped dye laser. For a hydrogen pressure of 350 psi, the first Stokes conversion efficiencies to 940 nm were 20% and 35% when using a conventional and waveguide Raman cell, respectively. We measured the linewidth of the first Stokes line at high cell pressures and inferred collisional broadening coefficients that agree well with those previously measured in spontaneous Raman scattering.

  11. Raman-shifted dye laser for water vapor DIAL measurements

    NASA Technical Reports Server (NTRS)

    Grossmann, B. E.; Singh, U. N.; Cotnoir, L. J.; Wilkerson, T. D.; Higdon, N. S.; Browell, E. V.

    1987-01-01

    For improved DIAL measurements of water vapor in the upper troposphere or lower stratosphere, narrowband (about 0.03/cm) laser radiation at 720- and 940-nm wavelengths was generated by stimulated Raman scattering (SRS), using the narrow linewidth (about 0.02/cm) output of a Nd:YAG-pumped dye laser. For a hydrogen pressure of 350 psi, the first Stokes conversion efficiencies to 940 nm were 20 percent and 35 percent, when using a conventional and waveguide Raman cell, respectively. The linewidth of the first Stokes line at high cell pressures, and the inferred collisional broadening coefficients, agree well with those previously measured in spontaneous Raman scattering.

  12. Dye laser amplifier including an improved window configuration for its dye beam

    DOEpatents

    O'Neil, R.W.; Davin, J.M.

    1992-12-01

    A dye laser amplifier in which a continuously replenished supply of dye is excited with a first light beam in order to amplify the intensity of a second different light beam passing therethrough is disclosed herein. This amplifier includes a cell though which a continuous stream of the dye is caused to pass, and means for directing the first beam into the cell while the second beam is directed into and through the same cell. There is also disclosed herein a specific improvement to this amplifier which resides in the use of a pair of particularly configured windows through which the second beam passes along fixed paths as the second beam enters and exits the dye cell. Each of these windows has a relatively thick main section which is substantially larger in dimensions transverse to its beam path than the cross section of the second beam itself, whereby to add structural integrity to the overall window. At the same time, the latter includes a second section which is disposed entirely within the confines of the main section and through which the second beam is intended to pass in its entirety. This second section is made substantially thinner than the main section in order to reduce optical distortion as the second beam passes therethrough. 4 figs.

  13. Dye laser amplifier including an improved window configuration for its dye beam

    DOEpatents

    O'Neil, Richard W.; Davin, James M.

    1992-01-01

    A dye laser amplifier in which a continuously replenished supply of dye is excited with a first light beam in order to amplify the intensity of a second different light beam passing therethrough is disclosed herein. This amplifier includes a cell though which a continuous stream of the dye is caused to pass, and means for directing the first beam into the cell while the second beam is directed into and through the same cell. There is also disclosed herein a specific improvement to this amplifier which resides in the use of a pair of particularly configured windows through which the second beam passes along fixed paths as the second beam enters and exits the dye cell. Each of these windows has a relatively thick main section which is substantially larger in dimensions transverse to its beam path than the cross section of the second beam itself, whereby to add structural integrity to the overall window. At the same time, the latter includes a second section which is disposed entirely within the confines of the main section and through which the second beam is intended to pass in its entirety. This second section is made substantially thinner than the main section in order to reduce optical distortion as the second beam passes therethrough.

  14. Identification Of Natural Dyes On Archaeological Textile Objects Using Laser Induced Fluorescent Technique

    NASA Astrophysics Data System (ADS)

    Abdel-Kareem, O.; Eltokhy, A.; Harith, M. A.

    2011-09-01

    This study aims to evaluate the use of Laser Fluorescent as a non-destructive technique for identification of natural dyes on archaeological textile objects. In this study wool textile samples were dyed with 10 natural dyes such as cochineal, cutch, henna, indigo, Lac, madder, safflower, saffron, sumac and turmeric. These dyes common present on archaeological textile objects to be used as standard dyed textile samples. These selected natural dyes will be used as known references that can be used a guide to identify unknown archaeological dyes. The dyed textile samples were investigated with laser radiation in different wavelengths to detect the best wavelengths for identification each dye. This study confirms that Laser Florescent is very useful and a rapid technique can be used as a non-destructive technique for identification of natural dyes on archaeological textile objects. The results obtained with this study can be a guide for all conservators in identification of natural organic dyes on archaeological textile objects.

  15. Identification Of Natural Dyes On Archaeological Textile Objects Using Laser Induced Fluorescent Technique

    SciTech Connect

    Abdel-Kareem, O.; Eltokhy, A.; Harith, M. A.

    2011-09-22

    This study aims to evaluate the use of Laser Fluorescent as a non-destructive technique for identification of natural dyes on archaeological textile objects. In this study wool textile samples were dyed with 10 natural dyes such as cochineal, cutch, henna, indigo, Lac, madder, safflower, saffron, sumac and turmeric. These dyes common present on archaeological textile objects to be used as standard dyed textile samples. These selected natural dyes will be used as known references that can be used a guide to identify unknown archaeological dyes. The dyed textile samples were investigated with laser radiation in different wavelengths to detect the best wavelengths for identification each dye. This study confirms that Laser Florescent is very useful and a rapid technique can be used as a non-destructive technique for identification of natural dyes on archaeological textile objects. The results obtained with this study can be a guide for all conservators in identification of natural organic dyes on archaeological textile objects.

  16. Absolute tracer dye concentration using airborne laser-induced water Raman backscatter

    NASA Technical Reports Server (NTRS)

    Hoge, F. E.; Swift, R. N.

    1981-01-01

    The use of simultaneous airborne-laser-induced dye fluorescence and water Raman backscatter to measure the absolute concentration of an ocean-dispersed tracer dye is discussed. Theoretical considerations of the calculation of dye concentration by the numerical comparison of airborne laser-induced fluorescence spectra with laboratory spectra for known dye concentrations using the 3400/cm OH-stretch water Raman scatter as a calibration signal are presented which show that minimum errors are obtained and no data concerning water mass transmission properties are required when the laser wavelength is chosen to yield a Raman signal near the dye emission band. Results of field experiments conducted with an airborne conical scan lidar over a site in New York Bight into which rhodamine dye had been injected in a study of oil spill dispersion are then indicated which resulted in a contour map of dye concentrations, with a minimum detectable dye concentration of approximately 2 ppb by weight.

  17. Laser velocimetry with fluorescent dye-doped polystyrene microspheres.

    PubMed

    Lowe, K Todd; Maisto, Pietro; Byun, Gwibo; Simpson, Roger L; Verkamp, Max; Danehy, Paul M; Tiemsin, Pacita I; Wohl, Christopher J

    2013-04-15

    Simultaneous Mie scattering and laser-induced fluorescence (LIF) signals are obtained from individual polystyrene latex microspheres dispersed in an air flow. Microspheres less than 1 μm mean diameter were doped with two organic fluorescent dyes, Rhodamine B (RhB) and dichlorofluorescein (DCF), intended either to provide improved particle-based flow velocimetry in the vicinity of surfaces or to provide scalar flow information (e.g., marking one of two fluid streams). Both dyes exhibit measureable fluorescence signals that are on the order of 10(-3) to 10(-4) times weaker than the simultaneously measured Mie signals. It is determined that at the conditions measured, 95.5% of RhB LIF signals and 32.2% of DCF signals provide valid laser-Doppler velocimetry measurements compared with the Mie scattering validation rate with 6.5 W of 532 nm excitation, while RhB excited with 1.0 W incident laser power still exhibits 95.4% valid velocimetry signals from the LIF channel. The results suggest that the method is applicable to wind tunnel measurements near walls where laser flare can be a limiting factor and monodisperse particles are essential.

  18. Laser velocimetry with fluorescent dye-doped polystyrene microspheres.

    PubMed

    Lowe, K Todd; Maisto, Pietro; Byun, Gwibo; Simpson, Roger L; Verkamp, Max; Danehy, Paul M; Tiemsin, Pacita I; Wohl, Christopher J

    2013-04-15

    Simultaneous Mie scattering and laser-induced fluorescence (LIF) signals are obtained from individual polystyrene latex microspheres dispersed in an air flow. Microspheres less than 1 μm mean diameter were doped with two organic fluorescent dyes, Rhodamine B (RhB) and dichlorofluorescein (DCF), intended either to provide improved particle-based flow velocimetry in the vicinity of surfaces or to provide scalar flow information (e.g., marking one of two fluid streams). Both dyes exhibit measureable fluorescence signals that are on the order of 10(-3) to 10(-4) times weaker than the simultaneously measured Mie signals. It is determined that at the conditions measured, 95.5% of RhB LIF signals and 32.2% of DCF signals provide valid laser-Doppler velocimetry measurements compared with the Mie scattering validation rate with 6.5 W of 532 nm excitation, while RhB excited with 1.0 W incident laser power still exhibits 95.4% valid velocimetry signals from the LIF channel. The results suggest that the method is applicable to wind tunnel measurements near walls where laser flare can be a limiting factor and monodisperse particles are essential. PMID:23595429

  19. Red/blue spectral shifts of laser-induced fluorescence emission due to different nanoparticle suspensions in various dye solutions.

    PubMed

    Bavali, A; Parvin, P; Mortazavi, S Z; Mohammadian, M; Mousavi Pour, M R

    2014-08-20

    Red/blue shifts of laser-induced fluorescence (LIF) are investigated using several guest dielectric nanoscatterers, such as TiO2, ZnO, Al2O3, and SiO2, in the host Rd6G, RdB, Coumarin 4, and Coumarin 7 ethanolic solutions. A couple of inflection points are identified varying nanoparticle (NP) density into dye solutions based on LIF spectroscopy. The inflection of the spectral shift exhibits that the suspension of NPs in dye solutions significantly involves a couple of competitive chemical and optical mechanisms during photon traveling in scattering media regarding ballistic and diffusive transport. It is shown that the low, medium, and high NP additives in fluorescent suspension induce blue, red, and blue spectral shifts, respectively.

  20. Hair ignition by dye laser for port-wine stain: risk factors evaluated.

    PubMed

    Molin, L; Hallgren, S

    1999-04-01

    Flashlamp-pumped pulsed dye laser is the preferred treatment for port-wine stain. Vascular hemoglobin and epidermal melanin are competing sites for dye laser absorption and damage. The case presented illustrates the potential hazard of ignition induced by dye laser treatment on the face of a patient receiving inhalation anesthesia. A 6-year-old girl with almost black hair was treated for a port-wine stain covering most of the right half of her face. She was treated with dye laser under general anesthesia administered by mask. A laser pulse close to the upper part of the eyebrow induced a blaze and the eyebrow was instantly destroyed by the fire. Regrowth of the eyebrow was complete after a few months. Hair specimens of various colors were exposed experimentally to dye laser irradiation in room and oxygen-saturated atmospheres. Risk factors of ignition are high laser dosage, a high oxygen level, repeated pulses and dark colored hair.

  1. Investigating Two-Photon-Induced Fluorescence in Rhodamine-6G in Presence of Cetyl-Trimethyl-Ammonium-Bromide.

    PubMed

    Maurya, Sandeep Kumar; Yadav, Dheerendra; Goswami, Debabrata

    2016-09-01

    We investigate the effect of cetyl-trimethyl-ammonium-bromides (CTAB) concentration on the fluorescence of Rhodamine-6G in water. This spectroscopic study of Rhodamine-6G in presence of CTAB was performed using two-photon-induced-fluorescence at 780 nm wavelength using high repetition rate femtosecond laser pulses. We report an increment of ∼10 % in the fluorescence in accordance with ∼12 % enhancement in the absorption intensity of the dye molecule around the critical micellar concentration. We discuss the possible mechanism for the enhancement in the two-photon fluorescence intensity and the importance of critical micellar concentration. PMID:27324955

  2. Hydrogen peroxide sensor using laser grade dye Rhodamine B

    NASA Astrophysics Data System (ADS)

    Pattanaik, Amitansu; Sahare, P. D.; Nanda, Maitreyee

    2007-11-01

    Many chemical sensors based on fluorescence spectroscopy have been reported in applications, ranging from biomedical and environmental monitoring to industrial process control. In these diverse applications, the analyte can be probed directly, by measuring its intrinsic absorption, or by incorporating some transduction mechanism such as reagent chemistry to enhance sensitivity and selectivity. Hydrogen Peroxide is a colorless liquid. It is a common oxidizing and bleaching agent. It plays an important role in High Power Laser such as Chemical Oxygen Iodine Laser (COIL). As it is on the Hazardous substance list and on the special health hazard substance list, detection of Hydrogen Peroxide is of great importance. In the present study the detection of hydrogen Peroxide is by fluorescence quenching of laser grade dye Rhodamine B. Estimation of rate constant of the bimolecular quenching reaction is made.

  3. Laser beam control and diagnostic systems for the copper-pumped dye laser system at Lawrence Livermore National Laboratory

    SciTech Connect

    Bliss, E.S.; Peterson, R.L.; Salmon, J.T.; Thomas, R.A.

    1992-11-01

    The laser system described in the previous paper is used for experiments in which success requires tight tolerances on beam position, direction, and wavefront. Indeed, the optimum performance of the laser itself depends on careful delivery of copper laser light to the dye amplifiers, precise propagation of dye laser beams through restricted amplifier apertures, and accurate monitoring of laser power at key locations. This paper describes the alignment systems, wavefront correction systems, and laser diagnostics systems which ensure that the control requirements of both the laser and associated experiments are met. Because laser isotope separation processes utilize more than one wavelength, these systems monitor and control multiple wavelengths simultaneously.

  4. Preparation of certain m-aminophenols and the use thereof for preparation of laser dyes

    DOEpatents

    Hammond, Peter R.

    1986-01-01

    Methods are provided for making certain m-aminophenols using a sulfonation/alkali fusion procedure. The aminophenols are key intermediates in the synthesis of dyes, particularly efficient, stable dyes for laser application. Preparations of some rhodamine and phenoxazone dyes from the m-aminophenols are described.

  5. Preparation of certain m-aminophenols and the use thereof for preparation of laser dyes

    DOEpatents

    Hammond, P.R.

    1983-12-29

    Methods are provided for making certain m-aminophenols using a sulfonation/alkali fusion procedure. The aminophenols are key intermediates in the synthesis of dyes, particularly efficient, stable dyes for laser application. Preparations of some rhodamine and phenoxazone dyes from the m-aminophenols are described.

  6. Photophysical and photochemical properties of coumarin laser dyes in amphiphilic media

    NASA Astrophysics Data System (ADS)

    Jones, G., II; Jackson, W. R.; Kanoktanaporn, S.; Bergmark, W. R.

    1983-10-01

    Photophysical properties of coumarin laser dyes solubilized in aqueous detergent or cyclodextrin solutions have been investigated. Dyes appear to be incorporated in hydrated (hydrogen bonded) sites within detergent micelles. Photodegradation is inhibited for detergent solubilized dye. Electron transfer photochemistry is examined by flash photolysis.

  7. Laser Assisted Cancer Immunotherapy: Optical Dye Distribution in Tumors

    NASA Astrophysics Data System (ADS)

    Swindle, Ryan

    2005-03-01

    Laser Assisted Cancer Immunotherapy is an experimental modality used to treat superficial tumors implanted on sterile Balb/C mice. The goal of the project is to induce a positive immune response toward a complete eradication of the primary tumor. Optimal necrosis results from depositing the maximum amount of thermal energy into the tumor without damaging the surrounding healthy tissue. In our laboratory, the optical dye, indocyanine green (ICG), is injected into the center of the tumor prior to surface and interstitial laser irradiation. A diode laser operating at a wavelength near 804 nm exerts thermal energy into the tumor via ICG absorption at 790 nm. Maximum immune response should occur with a uniform distribution of ICG throughout the tumor. By mapping the ICG distribution, the spatial homogeneity of the dye can be determined, which, in turn, mimics the tumor temperature profile. After excision, the tumors were cut into samples of approximately 250 microns thick and dissolved in a chemical detergent. Each sample was run through an absorption spectrometer to determine the distribution of ICG throughout the tumor. Results for both radial and depth profiles of ICG tumor distribution will be presented.

  8. Laser inactivation of periodontal bacteria using photosensitizing dyes

    NASA Astrophysics Data System (ADS)

    Golding, Paul S.; Maddocks, L.; King, Terence A.; Drucker, D. B.

    1996-12-01

    We demonstrate the killing of the oral bacteria Prevotella nigrescens using a photosensitizer and light from a 10 Hz, frequency doubled, Q-switched Nd:YAG pumped dye laser, with modified oscillator to increase output power. This system produced light at wavelengths close to 620 nm, the absorption maximum of the photosensitizing agent, malachite green isothiocyanate, a wavelength that is not significantly absorbed by tissue. A bacterial reduction of 97.5 percent was achieved at an energy density of 0.67 J/cm2 and exposure times of 300 seconds.

  9. Raman-shifted dye laser for water vapor DIAL measurements

    SciTech Connect

    Grossmann, B.E.; Singh, U.N.; Higdon, N.S.; Cotnoir, L.J.; Wilkerson, T.D.; Browell, E.V.

    1987-05-01

    For improved DIAL measurements of water vapor in the upper troposphere or lower stratosphere, we have generated narrowband (--0.03-cm/sup -1/) laser radiation at 720- and 940-nm wavelengths by stimulated Raman scattering (SRS) using the narrow linewidth (--0.02-cm/sup -1/) output of a Nd:YAG-pumped dye laser. For a hydrogen pressure of 350 psi, the first Stokes conversion efficiencies to 940 nm were 20% and 35% when using a conventional and waveguide Raman cell, respectively. We measured the linewidth of the first Stokes line at high cell pressures and inferred collisional broadening coefficients that agree well with those previously measured in spontaneous Raman scattering.

  10. Circularly polarized laser emission induced in isotropic and achiral dye systems

    PubMed Central

    Cerdán, Luis; García-Moreno, Sara; Costela, Angel; García-Moreno, Inmaculada; de la Moya, Santiago

    2016-01-01

    The production of efficient, tunable, and switchable circularly polarized laser emission would have far reaching implications in optical communications or biophotonics. In this work, it is demonstrated the direct generation of circularly polarized (CP) laser emission in achiral and isotropic dye laser systems without the use of extracavity polarizing elements, and without resorting to chiral dyes, chiral liquid crystal matrices, or interferometric methods. The origin of this ellipticity arises from the dynamic birefringence induced by the strong and polarized laser pumping and the subsequent orientation anisotropy of the excited molecular dipoles. A complete polarimetric characterization of the polarization state of conventional dye laser oscillators as a function of different experimental parameters is performed and it is shown that the generated light always possesses a certain level of circularity that changes in a distinctive way with pump energy and polarization. These results demonstrate that it is possible to generate and modulate CP laser light from efficient and photostable conventional laser dyes. PMID:27350073

  11. Circularly polarized laser emission induced in isotropic and achiral dye systems

    NASA Astrophysics Data System (ADS)

    Cerdán, Luis; García-Moreno, Sara; Costela, Angel; García-Moreno, Inmaculada; de La Moya, Santiago

    2016-06-01

    The production of efficient, tunable, and switchable circularly polarized laser emission would have far reaching implications in optical communications or biophotonics. In this work, it is demonstrated the direct generation of circularly polarized (CP) laser emission in achiral and isotropic dye laser systems without the use of extracavity polarizing elements, and without resorting to chiral dyes, chiral liquid crystal matrices, or interferometric methods. The origin of this ellipticity arises from the dynamic birefringence induced by the strong and polarized laser pumping and the subsequent orientation anisotropy of the excited molecular dipoles. A complete polarimetric characterization of the polarization state of conventional dye laser oscillators as a function of different experimental parameters is performed and it is shown that the generated light always possesses a certain level of circularity that changes in a distinctive way with pump energy and polarization. These results demonstrate that it is possible to generate and modulate CP laser light from efficient and photostable conventional laser dyes.

  12. Circularly polarized laser emission induced in isotropic and achiral dye systems.

    PubMed

    Cerdán, Luis; García-Moreno, Sara; Costela, Angel; García-Moreno, Inmaculada; de la Moya, Santiago

    2016-01-01

    The production of efficient, tunable, and switchable circularly polarized laser emission would have far reaching implications in optical communications or biophotonics. In this work, it is demonstrated the direct generation of circularly polarized (CP) laser emission in achiral and isotropic dye laser systems without the use of extracavity polarizing elements, and without resorting to chiral dyes, chiral liquid crystal matrices, or interferometric methods. The origin of this ellipticity arises from the dynamic birefringence induced by the strong and polarized laser pumping and the subsequent orientation anisotropy of the excited molecular dipoles. A complete polarimetric characterization of the polarization state of conventional dye laser oscillators as a function of different experimental parameters is performed and it is shown that the generated light always possesses a certain level of circularity that changes in a distinctive way with pump energy and polarization. These results demonstrate that it is possible to generate and modulate CP laser light from efficient and photostable conventional laser dyes. PMID:27350073

  13. Circularly polarized laser emission induced in isotropic and achiral dye systems.

    PubMed

    Cerdán, Luis; García-Moreno, Sara; Costela, Angel; García-Moreno, Inmaculada; de la Moya, Santiago

    2016-06-28

    The production of efficient, tunable, and switchable circularly polarized laser emission would have far reaching implications in optical communications or biophotonics. In this work, it is demonstrated the direct generation of circularly polarized (CP) laser emission in achiral and isotropic dye laser systems without the use of extracavity polarizing elements, and without resorting to chiral dyes, chiral liquid crystal matrices, or interferometric methods. The origin of this ellipticity arises from the dynamic birefringence induced by the strong and polarized laser pumping and the subsequent orientation anisotropy of the excited molecular dipoles. A complete polarimetric characterization of the polarization state of conventional dye laser oscillators as a function of different experimental parameters is performed and it is shown that the generated light always possesses a certain level of circularity that changes in a distinctive way with pump energy and polarization. These results demonstrate that it is possible to generate and modulate CP laser light from efficient and photostable conventional laser dyes.

  14. Scaling up a high average power dye laser amplifier and its new pumping designs

    SciTech Connect

    Takehisa, K.

    1997-01-01

    Scaling up of a high average power dye laser amplifier is discussed. Differences in the characteristics between a high average power dye laser amplifier with transverse pumping and longitudinal pumping are presented by a simple theory and simulations. The simulation results for dye laser amplifiers of 10-kW average output power show that longitudinal pumping is as efficient as transverse pumping with the potential of orders of magnitude lower dye flow rate. New pumping designs are also proposed for a dye laser amplifier aimed to achieve high gain with high efficiency to reduce the number of amplifier stages. Simulation results suggest that the new designs, in comparison with a conventional amplifier, can produce several orders of magnitude higher gain without decreasing the conversion efficiency. {copyright} 1997 Optical Society of America

  15. Technology and engineering aspects of high power pulsed single longitudinal mode dye lasers

    NASA Astrophysics Data System (ADS)

    Rawat, V. S.; Mukherjee, Jaya; Gantayet, L. M.

    2015-09-01

    Tunable single mode pulsed dye lasers are capable of generating optical radiations in the visible range having very small bandwidths (transform limited), high average power (a few kW) at a high pulse repetition rate (a few tens of kHz), small beam divergence and relatively higher efficiencies. These dye lasers are generally utilized laser dyes dissolved in solvents such as water, heavy water, ethanol, methanol, etc. to provide a rapidly flowing gain medium. The dye laser is a versatile tool, which can lase either in the continuous wave (CW) or in the pulsed mode with pulse duration as small as a few tens of femtoseconds. In this review, we have examined the several cavity designs, various types of gain mediums and numerous types of dye cell geometries for obtaining the single longitudinal mode pulsed dye laser. Different types of cavity configuration, such as very short cavity, short cavity with frequency selective element and relatively longer cavity with multiple frequency selective elements were reviewed. These single mode lasers have been pumped by all kinds of pumping sources such as flash lamps, Excimer, Nitrogen, Ruby, Nd:YAG, Copper Bromide and Copper Vapor Lasers. The single mode dye lasers are either pumped transversely or longitudinally to the resonator axis. The pulse repletion rate of these pump lasers were ranging from a few Hz to a few tens of kHz. Physics technology and engineering aspects of tuning mechanism, mode hop free scanning and dye cell designs are also presented in this review. Tuning of a single mode dye laser with a resolution of a few MHz per step is a technologically challenging task, which is discussed here.

  16. A linewidth-narrowed and frequency-stabilized dye laser for application in laser cooling of molecules.

    PubMed

    Dai, D P; Xia, Y; Yin, Y N; Yang, X X; Fang, Y F; Li, X J; Yin, J P

    2014-11-17

    We demonstrate a robust and versatile solution for locking the continuous-wave dye laser for applications in laser cooling of molecules which need linewidth-narrowed and frequency-stabilized lasers. The dye laser is first stabilized with respect to a reference cavity by Pound-Drever-Hall (PDH) technique which results in a single frequency with the linewidth 200 kHz and short-term stabilization, by stabilizing the length of the reference cavity to a stabilized helium-neon laser we simultaneously transfer the ± 2 MHz absolute frequency stability of the helium-neon laser to the dye laser with long-term stabilization. This allows the dye laser to be frequency chirped with the maximum 60 GHz scan range while its frequency remains locked. It also offers the advantages of locking at arbitrary dye laser frequencies, having a larger locking capture range and frequency scanning range to be implemented via software. This laser has been developed for the purpose of laser cooling a molecular magnesium fluoride beam.

  17. A linewidth-narrowed and frequency-stabilized dye laser for application in laser cooling of molecules.

    PubMed

    Dai, D P; Xia, Y; Yin, Y N; Yang, X X; Fang, Y F; Li, X J; Yin, J P

    2014-11-17

    We demonstrate a robust and versatile solution for locking the continuous-wave dye laser for applications in laser cooling of molecules which need linewidth-narrowed and frequency-stabilized lasers. The dye laser is first stabilized with respect to a reference cavity by Pound-Drever-Hall (PDH) technique which results in a single frequency with the linewidth 200 kHz and short-term stabilization, by stabilizing the length of the reference cavity to a stabilized helium-neon laser we simultaneously transfer the ± 2 MHz absolute frequency stability of the helium-neon laser to the dye laser with long-term stabilization. This allows the dye laser to be frequency chirped with the maximum 60 GHz scan range while its frequency remains locked. It also offers the advantages of locking at arbitrary dye laser frequencies, having a larger locking capture range and frequency scanning range to be implemented via software. This laser has been developed for the purpose of laser cooling a molecular magnesium fluoride beam. PMID:25402105

  18. PicoGreen dye as an active medium for plastic lasers

    NASA Astrophysics Data System (ADS)

    Pradeep, C.; Vallabhan, C. P. G.; Radhakrishnan, P.; Nampoori, V. P. N.

    2015-08-01

    Deoxyribonucleic acid lipid complex thin films are used as a host material for laser dyes. We tested PicoGreen dye, which is commonly used for the quantification of single and double stranded DNA, for its applicability as lasing medium. PicoGreen dye exhibits enhanced fluorescence on intercalation with DNA. This enormous fluorescence emission is amplified in a planar microcavity to achieve yellow lasing. Here the role of DNA is not only a host medium, but also as a fluorescence dequencher. With the obtained results we have ample reasons to propose PicoGreen dye as a lasing medium, which can lead to the development of DNA based bio-lasers.

  19. Composition and method of preparation of solid state dye laser rods

    DOEpatents

    Hermes, Robert E.

    1992-01-01

    The present invention includes solid polymeric-host laser rods prepared using bulk polymerization of acrylic acid ester comonomers which, when admixed with dye(s) capable of supporting laser oscillation and polymerized with a free radical initiator under mild thermal conditions, produce a solid product having the preferred properties for efficient lasing. Unsaturated polymerizable laser dyes can also be employed as one of the comonomers. Additionally, a method is disclosed which alleviates induced optical stress without having to anneal the polymers at elevated temperatures (>85.degree. C.).

  20. Detection of single rhodamine 6g molecules in levitated microdroplets

    SciTech Connect

    Barnes, M.D.; Ng, K.C.; Whitten, W.B.; Ramsey, J.M. )

    1993-09-01

    Single Rhodamine 6G (R6G) molecules in levitated glycerol microdroplets have been detected with signal-to-noise ratios of >40 using CW laser-induced fluorescence. The fluorescence signal from single R6G molecules was identified by the magnitude of the fluorescence signal and by the unique time dependence of the fluorescence count rate before photobleaching. This high sensitivity allows single molecules to be counted by use of a digital detection approach offering significantly lower detection limits than those possible with conventional detection methods. 27 refs., 6 figs.

  1. Development of magnetic luminescent core/shell nanocomplex particles with fluorescence using Rhodamine 6G

    SciTech Connect

    Lee, Hee Uk; Song, Yoon Seok; Park, Chulhwan; Kim, Seung Wook

    2012-12-15

    Graphical abstract: Display Omitted Highlights: ► A simple method was developed to synthesize Co-B/SiO{sub 2}/dye/SiO{sub 2} composite particles. ► The magnetic particle shows that highly luminescent and core/shell particles are formed. ► Such core/shell particles can be easily suspended in water. ► The magnetic particles could detect fluorescence for the application of biosensor. -- Abstract: A simple and reproducible method was developed to synthesize a novel class of Co-B/SiO{sub 2}/dye/SiO{sub 2} composite core/shell particles. Using a single cobalt core, Rhodamine 6G of organic dye molecules was entrapped in a silica shell, resulting in core/shell particles of ∼200 nm diameter. Analyses using a variety of techniques such as transmission electron microscopy, X-ray photoelectron spectroscopy, vibration sample magnetometry, confocal laser scanning microscopy, and fluorescence intensity demonstrated that dye molecules were trapped inside the core/shell particles. A photoluminescence investigation showed that highly luminescent and photostable core/shell particles were formed. Such core/shell particles can be easily suspended in water. The synthesized magnetic particles could be used to detect fluorescence on glass substrate arrays for bioassay and biosensor applications.

  2. Invasive leg vein treatment with 1064/1319 Nd:YAG laser: combination with dye laser treatment

    NASA Astrophysics Data System (ADS)

    Smucler, Roman; Horak, Ladislav; Mazanek, Jiri

    1999-06-01

    More than 2 500 leg veins patients were treated with dye laser / ScleroPlus, Candela, USA / successfully in our clinic and we use this therapy as the basic cosmetics treatment. But especially diameter of leg vein is limiting factor. Very often we have to treat some cases that are not ideal for classical surgical or for dye laser method. We decided to make invasive perivenous laser coagulation. We adapted original Czech 1064/1319 nm Nd:YAG laser / US patent pending /, which is new combine tool, for invasive application. Principe: After we have penetrated the cutis with laser fiber we coagulate leg veins during slowly perivenous motion. Perfect preoperative examination is a condition of success. After 15 months we have very interesting results. Some patients / 15%/ were perfect treated only with this possibility but excellent results are acquired from combination with dye laser.

  3. Infantile hemangioma: pulsed dye laser versus surgical therapy

    NASA Astrophysics Data System (ADS)

    Remlova, E.; Dostalova, T.; Michalusova, I.; Vranova, J.; Jelinkova, H.; Hubacek, M.

    2014-05-01

    Hemangioma is a mesenchymal benign tumor formed by blood vessels. Anomalies affect up to 10% of children and they are more common in females than in males. The aim of our study was to compare the treatment efficacy, namely the curative effect and adverse events, such as loss of pigment and appearance of scarring, between classical surgery techniques and laser techniques. For that reason a group of 223 patients with hemangioma was retrospectively reviewed. For treatment, a pulsed dye laser (PDL) (Rhodamine G, wavelength 595 nm, pulsewidth between 0.45 and 40 ms, spot diameter 7 mm, energy density 9-11 J cm-2) was used and the results were compared with a control group treated with classical surgical therapy under general anesthesia. The curative effects, mainly number of sessions, appearance of scars, loss of pigment, and relapses were evaluated as a marker of successful treatment. From the results it was evident that the therapeutic effects of both systems are similar. The PDL was successful in all cases. The surgery patients had four relapses. Classical surgery is directly connected with the presence of scars, but the system is safe for larger hemangiomas. It was confirmed that the PDL had the optimal curative effect without scars for small lesions (approximately 10 mm). Surgical treatment under general anesthesia is better for large hemangiomas; the disadvantage is the presence of scars.

  4. High-efficiency high-energy flashlamp-pumped dye laser

    SciTech Connect

    Jethwa, J.; Anufrik, S.S.; Docchio, F.

    1982-08-01

    A flashlamp-pumped dye laser using barium sulfate or polytetrafluorethylene powders as diffuse reflection in a close-coupled pumping geometry is described. Long pulse pumping (approx.15 ..mu..sec) and use of a vaccum-walled dye cell gave an efficiency of 0.8%.

  5. Measuring the Dispersion Curve of a PMMA-Fibre Optic Cable Using a Dye Laser

    ERIC Educational Resources Information Center

    Zorba, Serkan; Farah, Constantine; Pant, Ravi

    2010-01-01

    An advanced undergraduate laboratory experiment is outlined which uses a dye laser to map out the chromatic dispersion curve of a polymethyl methacrylate (PMMA) optical fibre. Seven different wavelengths across the visible spectrum are employed using five different dyes. The light pulse is split into two pulses, one to a nearby photodetector and…

  6. Developing a narrow-line laser spectrometer based on a tunable continuous-wave dye laser

    SciTech Connect

    Wang, Chun; Lv, Shasha; Bi, Jin; Liu, Fang; Li, Liufeng; Chen, Lisheng

    2014-08-15

    We present the development of a dye-laser-based spectrometer operating at 550–600 nm. The spectrometer will be used to detect an ultra-narrow clock transition ({sup 1}S{sub 0}-{sup 3}P{sub 0}) in an Ytterbium optical lattice clock and perform high-resolution spectroscopy of iodine molecules trapped in the sub-nanometer channels of zeolite crystal (AlPO{sub 4}-11). Two-stage Pound-Drever-Hall frequency stabilization is implemented on the tunable continuous-wave dye laser to obtain a reliable operation and provide stable laser radiations with two different spectral linewidths. In the first-stage frequency locking, a compact home-built intracavity electro-optic modulator is adopted for suppressing fast frequency noise. With an acquisition time of 0.1 s the 670-kHz linewidth of the free-running dye laser is reduced to 2 kHz when locked to a pre-stabilization optical cavity with a finesse of 1170. When the pre-stabilized laser is locked to a high-finesse optical cavity, a linewidth of 1.4 Hz (2 s) is observed and the frequency stability is 3.7 × 10{sup −15} (3 s). We also measure and analyze the individual noise contributions such as those from residual amplitude modulation and electronic noise. The ongoing upgrades include improving long-term frequency stability at time scales from 10 to 100 s and implementing continuous frequency scan across 10 GHz with radio-frequency precision.

  7. Comparison of the treatment of vascular lesions with the copper-vapor laser and flashlamp-pumped dye laser

    NASA Astrophysics Data System (ADS)

    Flock, Stephen T.; Waner, Milton; McGrew, Ben; Colvin, G. B.; Montague, Donna

    1992-08-01

    Vascular lesions such as port-wine stains and telangiectases are sometimes treated with carbon-dioxide lasers, argon lasers or argon-pumped dye lasers; however these lasers are non- specific in their thermal effect on tissues and as a result often cause significant scarring. Recently, evidence has accumulated that the flashlamp-pumped dye (585 nm) and copper- vapor (578 nm) lasers, which produce pulsed light that is efficiently absorbed by hemoglobin, are more selective in coagulating abnormal vascular tissue and as a result give a superior clinical result. It is not yet clear what the most important physical and biological mechanisms are during the light-tissue interaction mediated by these two lasers. The post-treatment sequence of events is different for tissue irradiated by each laser; most significantly, the flashlamp-pumped dye laser causes significant transient purpura, whereas the copper vapor laser causes blanching and eschar formation. The clinical outcome, that is regression of the lesion, is equally successful with either laser although some evidence has accumulated showing that the flashlamp-pumped dye laser is best suited to the treatment of small vessel disease while the copper-vapor laser is better for the treatment of large vessel disease. In this paper, we will discuss our observations of the treatment of vascular lesions on humans with the copper-vapor and flashlamp-pumped dye lasers using empirically derived efficacious treatment parameters. Mathematical models of light and heat propagation and in vivo experiments involving mice ears and rat skin flaps will be used to elucidate what we feel are the important underlying mechanisms of this vascular lesion laser therapy.

  8. Study of the generation characteristics of laser converters with dye-based wide-aperture solid--liquid active elements

    SciTech Connect

    Eremenko, A.S.; Zemskii, V.I.; Kolesnikov, Y.L.; Malinin, B.G.; Meshkovsky, I.K.; Savkin, N.P.; Stepanov, V.E.; Shildyaev, V.S.

    1986-11-01

    The lasing characteristics of an active element, consisting of a fine porous silicate matrix, has been studied. Molecules of a dye (rhodamine 6G) and an ethanol solution of the same dye were introduced into the cells. It has been shown that under conditions of large heat release (when thermooptical distortions begin to appear in the dye solutions), the solid--liquid element preserves the stability of its own lasing characteristics.

  9. New efficient laser dyes for the red region of the spectrum. Part 1. Peri-indenones

    NASA Astrophysics Data System (ADS)

    Belov, S. P.; Burdukova, O. A.; Komlev, I. V.; Petukhov, V. A.; Povedailo, V. A.; Semenov, M. A.

    2016-07-01

    We report the generation characteristics of ethanol solutions of twenty newly synthesised dyes belonging to peri-indenones, including benzanthrones and phenalemines. The tuning curves of these dyes, generating light in the orange and red spectral regions, are measured, and the wavelength tuning ranges are determined. The dependence of the generation energy on the pump energy in a non-selective cavity is measured. It is shown that some of the synthesised dyes surpass the widely used laser dyes in the energy efficiency and the width of the wavelength tuning range.

  10. A random laser made of nematic liquid crystal doped with a laser dye

    NASA Astrophysics Data System (ADS)

    Sznitko, L.; Kaliciak, K.; Adamow, A.; Mysliwiec, J.

    2016-06-01

    We report on random laser emission obtained in 5CB and E7 nematic liquid crystal (LC) mixtures doped with 1% weight to weight ratio of DCM laser dye. The LC cell was used as asymmetric planar waveguide were emission was collected from the edge of the sample. Variable stripe length method was utilized to estimate the gain and the losses coefficients. Both systems have shown the threshold energy fluence in order of several mJ/cm2. In both cases above Fredericks potential, significant increase of emission intensity was observed due to the increase of light scattering on liquid crystalline domains. Moreover the use of fifth order of diffraction grating covered with thin alumina film resulted in strong multimode and directional laser emission.

  11. Intersystem crossing from highly excited states. rhodamine 6G

    SciTech Connect

    Ryl'kov, V.V.; Cheshev, E.A.

    1985-09-01

    The authors carried out an investigation of ethanolic solutions of Rhodamine 6G (R6G) at 20 C by laser flash photolysis. The excitation of dilute (3 /SUP ./ 10/sup -5/ M) solutions of R6G with an initial optical density of 1.5 up to an intensity of 100 MW/cm/sup 2/ resulted in only weak triplet-triplet absorption. The introduction of additions of lithium chloride or lithium bromide in 0.1 M concentrations into a solution of R6G (3.10/sup -5/ M) resulted in the appearance of induced absorption and the introduction of an addition of lithium nitrate in the same concentration into the solution did not result in enhancement of triplet-triplet absorption.

  12. Fluorescent monodisperse spherical particles based on mesoporous silica containing rhodamine 6G

    NASA Astrophysics Data System (ADS)

    Trofimova, E. Yu.; Grudinkin, S. A.; Kukushkina, Yu. A.; Kurdyukov, D. A.; Medvedev, A. V.; Yagovkina, M. A.; Golubev, V. G.

    2012-06-01

    Fluorescent monodisperse spherical silica (SiO2) particles with a regular mesoporous structure containing encapsulated Rhodamine 6G (R6G) dye have been synthesized. The as-synthesized particles have been coated with SiO2 and SiO2-CTAB (cetyltrimethylammonium bromide, C16H33N(CH3)3Br) shells in order to prevent uncontrolled release of the dye from pores. The kinetics of R6G release from the pores of silica particles has been studied. It has been found that the particles synthesized by adding CTAB and R6G to the reaction mixture, as well as the particles coated with the SiO2-CTAB shell, are characterized by the maximum duration of dye release from the pores, which is probably associated with the formation of chemical bonds between R6G and CTAB molecules.

  13. Linewidth characteristics of Raman-shifted dye laser output at 720 and 940 nm

    NASA Technical Reports Server (NTRS)

    Grossmann, B. E.; Higdon, N. S.; Higdon, N. S.; Higdon, N. S.; Higdon, N. S.; Higdon, N. S.; Higdon, N. S.

    1986-01-01

    Existing DIAL systems for water vapor measurements in the troposphere operate at wavelengths near 720 nm. The use of stronger water vapor absorption lines in the range 930 to 960 nm will significantly improve DIAL measurements in the upper troposphere and lower stratosphere where water vapor concentrations are low. The generation of light at 940 nm using a frequency doubled Nd:YAG pumped dye laser is inefficient due to the small absorption if infrared dyes at the pump wavelength. However, 940 nm generation utilizing stimulated Raman scattering of dye lasers is attractive because of a potentially high conversion efficiency plus the possibility of retaining the narrow linewidth available from some dye lasers. The Raman conversion efficiency and line broadening are presented for first Stokes operation at 720 and 940 nm using hydrogen and deuterium as the Raman media.

  14. Direct laser interference patterning of polystyrene films doped with azo dyes, using 355 nm laser light

    NASA Astrophysics Data System (ADS)

    Broglia, M. F.; Suarez, S.; Soldera, F.; Mücklich, F.; Barbero, C. A.; Bellingeri, R.; Alustiza, F.; Acevedo, D.

    2014-05-01

    The generation of line-like periodic patterns by direct laser interference patterning (DLIP) of polystyrene films (PS) at a wavelength of 355 nm has been investigated. No structuration is achieved in plain PS due to the weak absorption of the polymer at 355 nm. On the other hand, patterning is achieved on films doped (PSd) with an azo dye (2-anisidine → 2-anisidine) which is incorporated in the polymer solution used for film preparation. Periodic micro-structures are generated. DLIP on PSd results in the swelling of the surface at low fluences, while at high laser intensities it causes the ablation of the regions at the interference maxima positions. The results contrast with the usual process of DLIP on PS (at shorter wavelengths, like 266 nm) where only ablation is detected. The results suggest that decomposition of the azo dye is the driving force of the patterning which therefore differ from the patterning obtained when plain PS is irradiated with laser light able to be absorbed by the aromatic ring in PS (e.g. 266 nm). The biocompatibility of these materials and adhesion of cells was tested, the data from in vitro assays shows that fibroblast cells are attached and proliferate extensively on the PSd films.

  15. Deposition of organic dyes for dye-sensitized solar cell by using matrix-assisted pulsed laser evaporation

    NASA Astrophysics Data System (ADS)

    Yen, Chih-Ping; Yu, Pin-Feng; Wang, Jyhpyng; Lin, Jiunn-Yuan; Chen, Yen-Mu; Chen, Szu-yuan

    2016-08-01

    The deposition of various distinct organic dyes, including ruthenium complex N3, melanin nanoparticle (MNP), and porphyrin-based donor-π-acceptor dye YD2-o-C8, by using matrix-assisted pulsed laser evaporation (MAPLE) for application to dye-sensitized solar cell (DSSC) is investigated systematically. It is found that the two covalently-bonded organic molecules, i.e., MNP and YD2-o-C8, can be transferred from the frozen target to the substrate with maintained molecular integrity. In contrast, N3 disintegrates in the process, presumably due to the lower bonding strength of metal complex compared to covalent bond. With the method, DSSC using YD2-o-C8 is fabricated, and an energy conversion efficiency of 1.47% is attained. The issue of the low penetration depth of dyes deposited by MAPLE and the possible resolution to it are studied. This work demonstrates that MAPLE could be an alternative way for deposition of organic dyes for DSSC.

  16. Prussian Blue Modified PLA Microcapsules Containing R6G for Ultrasonic/Fluorescent Bimodal Imaging Guided Photothermal Tumor Therapy.

    PubMed

    Feng, Shanshan; Wang, Jinrui; Ma, Fang; Liang, Xiaolong; Li, Xiaoda; Xing, Sen; Yue, Xiuli

    2016-03-01

    A theranostic agent has been successfully constructed for fluorescence/ultrasound dual-modal imaging guided photothermal therapy by loading the fluorescent dye R6G into polylactide microcapsules (PLA MCs) followed by deposition of Prussian blue nanoparticles (PB NPs) into the surface of PLA MCs. It was proved that the obtained microcapsules of R6G@PLA/PB MCs could serve as an efficient probe to simultaneously enhance fluorescence imaging and ultrasound imaging greatly in vivo. R6G@PLA/PB MCs exhibited significant photothermal cytotoxicity. Cancer cells could be killed efficiently through photothermal effects of R6G@PLA/PB MCs due to the strong absorption of PB NPs in the near infrared region under laser irradiation. In a word, R6G@PLA/PB MCs integrate multiple capabilities for effective tumor imaging and therapy. Such a single agent provides us a possibility to interpret accurately the obtained images, identify the size and location of the tumor, as well as guide and monitor the photothermal therapy.

  17. Effects of argon, dye, and Nd:YAG lasers on epidermis, dermis, and venous vessels

    SciTech Connect

    Landthaler, M.; Haina, D.; Brunner, R.; Waidelich, W.; Braun-Falco, O.

    1986-01-01

    The aim of the present study, which was performed at the dorsal aspects of the ears of guinea pigs, was to compare effects of different lasers on epidermis, dermis, and small venous vessels. Irradiations were performed with argon, dye, and Nd:YAG lasers. In the first series tissue repair processes were studied after argon laser application. Laser defects were excised after 1, 4, 8, and 14 days and were prepared for routine histological examination. The breadth of epidermal defect and extent of dermal coagulation and occlusion of vessels by thrombus formation were examined histologically. In a second series parameters of irradiation (ie, exposure time, laser power) of the three different lasers were changed systematically. Laser-induced morphological tissue changes could be best observed 24 hours after irradiation. Each of the lasers led to occlusion of vessels by thrombus formation and also coagulated epidermis and dermis. The extent of dermal and epidermal coagulation was less pronounced after dye laser application. Using short exposure times it was possible to reduce the extent of epidermal damage caused by argon and Nd:YAG lasers. Only 50-msec dye laser pulses led to intravascular thrombus formation without epidermal and dermal damage.

  18. Far-red polyurethane-host solid-state dye laser

    SciTech Connect

    Nikolaev, S V; Pozhar, V V; Dzyubenko, M I; Doroshenko, A O

    2009-09-30

    The output energy and emission spectrum of a solid-state dye laser using Oxazine 1 in polyurethane as the gain medium have been measured. Under microsecond pumping, efficient lasing has been obtained in the range 700-745 nm. The highest conversion efficiency and output energy achieved are 23% and 127 mJ, respectively. (lasers)

  19. QUANTITATIVE DETECTION OF ENVIRONMENTALLY IMPORTANT DYES USING DIODE LASER/FIBER-OPTIC RAMAN

    EPA Science Inventory

    A compact diode laser/fiber-optic Raman spectrometer is used for quantitative detection of environmentally important dyes. This system is based on diode laser excitation at 782 mm, fiber optic probe technology, an imaging spectrometer, and state-of-the-art scientific CCD camera. ...

  20. Influence of ZnO nanoparticles on Coumarin-503 and Coumarin-540 dye mixture for energy transfer distributed feedback dye lasers

    NASA Astrophysics Data System (ADS)

    Vijayaraghavan, G. V.; Basheer Ahamed, M.

    2016-07-01

    Using organic dyes Coumarin-503 (C503) and Coumarin-540 (C540) as donor and acceptor dyes, respectively, and Nd-YAG as pumping source (355 nm), an energy transfer-distributed feedback dye laser (ETDFDL) was constructed and its characteristics studied. Theoretical studies such as critical transfer radius (Ro), critical concentration (Co), and half quenching concentration (C1/2) were carried out using the absorption and fluorescence spectra of donor and acceptor dyes. On varying the input pump energy to the nanoparticle-incorporated ETDFDL and keeping the acceptor and donor dye concentrations constant, the lasing output obtained was found to be higher than that without the use of nanoparticles. This enhancement was due to the size, shape, and coupling between nanoparticles with the dye mixture. Tunability in the range of 435-553 nm was obtained for both donor (C503) and acceptor (C540) DFDL as a function of the angle of interfering beams of the pump laser.

  1. Development of a single-longitudinal-mode, high-peak-power, tunable pulsed dye laser

    SciTech Connect

    Black, J.F.; Valentini, J.J. )

    1994-09-01

    A compact, high-peak-power, user-friendly, single-longitudinal-mode (SLM) tunable dye laser has been developed. The device yields [gt]12 mJ pulses of 6 ns duration and [similar to]2.7[times]transform-limited linewidths of [lt]200 MHz. Seamless single-mode tunability of [gt]20 cm[sup [minus]1] is possible without resetting. The dye laser makes efficient use of the pump laser, with [similar to]10% conversion of the 532 nm pump energy to tunable dye power and occupies [lt]4 m[sup 2] (including pump laser and all diagnostics). The linewidth of the device can be switched from [lt]200 MHz SLM operation to [lt]0.5 cm[sup [minus]1] broadband modeless operation by moving one mirror. This allows rapid interchange between high-resolution scanning and a fast survey scan'' mode of operation to isolate the spectral region of interest at low resolution.

  2. Effect of dye laser pulse duration on selective cutaneous vascular injury

    SciTech Connect

    Garden, J.M.; Tan, O.T.; Kerschmann, R.; Boll, J.; Furumoto, H.; Anderson, R.R.; Parrish, J.A.

    1986-11-01

    The pulsed dye laser at 577 nm, a wavelength well absorbed by oxyhemoglobin, causes highly selective thermal injury to cutaneous blood vessels. Confinement of thermal damage to microvessels is, in theory, related to the laser exposure time (pulsewidth) on selective vascular injury. This study investigates the effect of 577 nm dye laser pulsewidth on selective vascular injury. Nine Caucasian, normal volunteers received 577 nm dye laser exposures at pulsewidths of 1.5-350 microseconds to their skin. Clinical purpura threshold exposure doses were determined in each volunteer, and biopsies of threshold and suprathreshold doses were examined in each volunteer. The laser exposure dose required to produce purpura increased as pulsewidth increased in all 9 subjects (p less than 0.001). This finding corresponds to laser pulsewidths equal to or exceeding the thermal relaxation times for dermal blood vessels. Histologically, vessel damage was selectively, but qualitatively, different for short vs long pulsewidths. Pulsewidths shorter than 20 microseconds caused vessel wall fragmentation and hemorrhage, whereas longer pulsewidths caused no significant hemorrhage. The purpura noted clinically appears to be due to a coagulum of intralumenal denatured erythrocytes. At 24 h, there was marked vessel wall necrosis at all pulsewidths. The short pulsewidths may cause erythrocyte vaporization, rapid thermal expansion, and mechanical vessel rupture with hemorrhage. Long pulsewidths appear to cause thermal denaturation with less mechanical vessel damage. The selective, nonhemorrhagic, vascular necrosis caused by the long-pulsewidth dye laser may lead to a more desirable clinical outcome in the therapy of blood vessel disease processes.

  3. Photophysical and photochemical properties of coumarin laser dyes in amphiphilic media. Technical report, 1 Jan-31 Oct 83

    SciTech Connect

    Jones, G. II; Jackson, W.R.; Kanoktanaporn, S.; Bergmark, W.R.

    1983-10-31

    Photophysical properties of coumarin laser dyes solubilized in aqueous detergent or cyclodextrin solutions have been investigated. Dyes appear to be incorporated in hydrated (hydrogen bonded) sites within detergent micelles. Photodegradation is inhibited for detergent solubilized dye. Electron transfer photochemistry is examined by flash photolysis.

  4. Histologic comparison of the pulsed dye laser and copper vapor laser effects on pig skin

    SciTech Connect

    Tan, O.T.; Stafford, T.J.; Murray, S.; Kurban, A.K. )

    1990-01-01

    Albino pig skin was exposed to the copper vapor (CVL) and flash-lamp pulsed dye (PDL) lasers at 578 nm with a 3 mm diameter spotsize over a range of fluences until purpura and whitening were first established. The total irradiation time was the parameter that was varied in order for the CVL to reach the desired fluence. The lowest fluence producing each clinical endpoint was designated the threshold fluence: 34 J/cm{sup 2} was required to produce purpura using the CVL compared to 7.5 J/cm{sup 2} with the PDL laser. Histologically, skin exposed to purpura fluences from the CVL revealed the presence of constricted, disrupted papillary dermal blood vessels with trapped RBC's within them which were unlike those exposed to PDL where the irradiated vessels were dilated and packed with masses of intravascular agglutinated RBC's. The whitening threshold fluences for the CVL and PDL lasers were 67 J/cm{sup 2} and 29 J/cm{sup 2}, respectively. Streaming of epidermal cells and dermal collagen denaturation were observed in CVL irradiated skin, compared to occasional dyskeratotic epidermal cells and focal dermal collagen denaturation following PDL exposure. The mechanisms responsible for the clinical and histologic changes produced by the two laser systems are discussed.

  5. Spectral and generating properties of active laser media based on dye-doped elastomers

    NASA Astrophysics Data System (ADS)

    Bezrodnyi, Vladimir; Derevyanko, N.; Ishchenko, Alexander A.; Slobodin, Valeriy V.; Karabanova, Ludmila V.

    2002-12-01

    The advantages of a polyurethane matrix over other polymers, which are widely used as active media for dye lasers, are analzyed. This matrix exhibits the photostability, service life, radiation resistance, conversion efficiency, and homogeneity of the dye distribution that surpass these properties for active media based on polyurethane acrylate, which has close physical and operation properties. These advantages result not only from the milder polymerization conditions but also from a lower probability of the formation of ion pairs and dye aggregates. A substantial suppression of these processes in polyurethane is explained by its greater polarity and solvation ability compared to polyurathane acrylate.

  6. Photoinduced processes in solid polymer solutions of dyes in an interference field of laser radiation

    SciTech Connect

    Sizykh, A G; Tarakanova, E A

    1998-12-31

    An investigation was made of the relationships governing the photochemical mechanism of formation of light-induced gratings in solid polymer solutions of a dye with a high quantum yield of the triplet states. The combined analysis of the results of real and numerical experiments was made for a solution of eosin K in gelatin. The protonation rate constant of the dye was measured and the dependence of the diffraction efficiency on the duration of irradiation was explained taking diffusion of the dye into account. A method was proposed for determination of the duffusion coefficient in a spatially modified interference field of the laser radiation. The diffusion coefficients were found. (nonlinear optical phenomena)

  7. Measurement of liquid sheet using laser tagging method by photochromic dye

    NASA Astrophysics Data System (ADS)

    Rosli, Nurrina Binti; Amagai, Kenji

    2014-12-01

    Liquid atomization system has been extensively applied as the most significant process in many industrial fields. In the internal combustion engine, the combustion phenomenon is strongly influenced by the spray characteristics of the fuel given by the atomization process. In order to completely understand the whole atomization process, a detail investigation of relations between the liquid jet characteristics and the breakup phenomenon is required. In this study, a non-intrusive method called as laser tagging method by photochromic dye has been developed with aim to study the breakup process of liquid sheet in detail, covering from the behavior in film until disintegrated into ligament and droplets. The laser tagging method by photochromic dye is based on a shift in the absorption spectrum of photochromic dye molecules tagged by ultraviolet laser. The shift results a color change at the tagged region of liquid containing the dye. In this study, the motions of the dye traces were analyzed as the liquid surface velocity. As a result, liquid sheet was found to keep its velocity constantly in film before suddenly increase around broken point. However, it then decreased after broken into droplets. By forming a set of four points of dye traces on the liquid sheet, the change of relative position of the set enabled the measurement of deformation and rotational motion of the liquid sheet. As a result, the normal strain of the liquid sheet parallel to the flow direction depended on the flow behavior of ligament formation.

  8. Dye lasers: Design, operation, and performance. March 1975-October 1989 (Citations from the Searchable Physics Information Notices data base). Report for Mar 75-Oct 89

    SciTech Connect

    Not Available

    1989-11-01

    This bibliography contains citations concerning the design, operation, and performance of dye lasers. Dye materials, pulse techniques, laser pumping systems, experimental applications, design of dye laser systems, and performance evaluations are considered. Modeling of dye laser operation is also discussed. Descriptions of system components and experimental variables, and their effects on laser output are included. References to other laser systems such as carbon dioxide lasers, x-ray lasers, and UV lasers are included in related bibliographies. (Contains 264 citations fully indexed and including a title list.)

  9. Pulsed dye laser application in ablation of vascular ectasias of the larynx: a preliminary animal study

    NASA Astrophysics Data System (ADS)

    Woo, Peak; Wang, Zhi; Perrault, Donald F., Jr.; McMillan, Kathleen; Pankratov, Michail M.

    1995-05-01

    Vascular ectasias (dilatation) and vascular lesions of the larynx are difficult to treat with exciting modalities. Varix (enlarged vessel) of the vocal folds, vocal fold hemorrhage, vascular polyp, hemangioma, intubation or contact granuloma are common problems which disturb voice. Current applications of CO2 laser and cautery often damage the delicate vocal fold cover. The 585 nm dermatologic pulsed dye laser may be an ideal substitute. Two adult canines were examined under anesthesia via microlaryngoscopy technique. Pulsed dye laser (SPTL-1a, Candela Laser Corp., Wayland, MA) energy was delivered via the micromanipulator with the 3.1-mm spot size in single pulses of 6, 8, and 10 Joules/cm2 and applied to the vessels of the vocal folds, epiglottis, and arytenoid cartilage. Endoscopic examination was carried out immediately after the treatment and at 4 weeks postoperatively. The animals were sacrificed at 3 weeks, larynges excised, and whole organ laryngeal section were prepared for histology. Pulsed dye laser thrombosed vessels of the vocal fold using 6 or 8 Joules/cm2. Vascular break and leakage occurred at 10 Joules/cm2. Follow up examination showed excellent vessel obliteration or thrombosis without scarring or injury to the overlying tissues. Histologic examination shows vascular thrombosis without inflammation and fibrosis in the vocal fold cover. Pulsed dye laser may have promise in treatment of vascular lesions of the larynx and upper airway.

  10. CF/sub 2/Cl/sub 2/ as a dye laser tuning gas: refractive-index measurements

    SciTech Connect

    McGee, T.J.; Burris, J. Jr.

    1981-10-15

    Freon 12 is used for pressure tuning a dye laser. The frequency doubled dye laser radiation is used to excite the spectrum of NO-..gamma.. bands as a function of pressure and to deduce the index of refraction of the freon. (AIP)

  11. Intracavity absorption with a continuous wave dye laser - Quantification for a narrowband absorber

    NASA Technical Reports Server (NTRS)

    Brobst, William D.; Allen, John E., Jr.

    1987-01-01

    An experimental investigation of the dependence of intracavity absorption on factors including transition strength, concentration, absorber path length, and pump power is presented for a CW dye laser with a narrow-band absorber (NO2). A Beer-Lambert type relationship is found over a small but useful range of these parameters. Quantitative measurement of intracavity absorption from the dye laser spectral profiles showed enhancements up to 12,000 (for pump powers near lasing threshold) when compared to extracavity measurements. The definition of an intracavity absorption coefficient allowed the determination of accurate transition strength ratios, demonstrating the reliability of the method.

  12. A nano-patterned photonic crystal laser with a dye-doped liquid crystal

    NASA Astrophysics Data System (ADS)

    Ko, Doo-Hyun; Morris, Stephen M.; Lorenz, Alexander; Castles, Flynn; Butt, Haider; Gardiner, Damian J.; Qasim, Malik M.; Wallikewitz, Bodo; Hands, Philip J. W.; Wilkinson, Timothy D.; Amaratunga, Gehan A. J.; Coles, Harry J.; Friend, Richard H.

    2013-07-01

    Covering a nano-patterned titanium dioxide photonic crystal (PC) within a well-oriented film of dye-doped liquid crystal (LC), a distributed feedback laser is constructed whereby the emission characteristics can be manipulated in-situ using an electric field. This hybrid organic-inorganic structure permits simultaneous selectivity of both the beam pattern and laser wavelength by electrical addressing of the LC director. In addition, laser emission is obtained both in the plane and normal to the PC. Along with experimental data, a theoretical model is presented that is based upon an approximate calculation of the band structure of this birefringent, tuneable laser device.

  13. Attogram detection limit for aqueous dye samples by laser-induced fluorescence

    SciTech Connect

    Dovichi, N.J.; Martin, J.C.; Keller, R.A.

    1983-02-18

    A modified flow cytometer has been used to detect attogram quantities of aqueous rhodamine 6G by laser-induced fluorescence analysis. A detection limit of 28 attograms (35,000 molecules) was obtained, nearly two orders of magnitude better than earlier measurements. The detection limit in concentration units was 1.4 x 10/sup -13/ mole per liter. During the 1-second measurement period, the total volume sampled was 0.42 microliter. On average, only half a rhodamine 6G molecule was present in the 6-picoliter probed volume.

  14. Master dye laser oscillator including a specific grating assembly for use therein

    DOEpatents

    Davin, J.M.

    1992-09-01

    A dye laser oscillator for producing a tuned dye beam is disclosed herein and includes, among other components, a beam output coupling assembly, a dye cell assembly, a beam expander assembly, an etalon assembly, and a grating assembly. Each of three assemblies is vertically supported from a horizontal base so as to be readily removable from the base without interference from or interfering with the other assemblies. The particular grating assembly disclosed is specifically designed for proper optical alignment with the intended path of the dye beam to be produced and for accurate pivotal movement relative to the beam path in order to function as a coarse tuning mechanism in the production of the ultimately tuned beam. 5 figs.

  15. Master dye laser oscillator including a specific grating assembly for use therein

    DOEpatents

    Davin, James M.

    1992-01-01

    A dye laser oscillator for producing a tuned dye beam is disclosed herein and includes, among other components, a beam output coupling assembly, a dye cell assembly, a beam expander assembly, an etalon assembly, and a grating assembly. Each of three assemblies is vertically supported from a horizontal base so as to be readily removable from the base without interference from or interfering with the other assemblies. The particular grating assembly disclosed is specifically designed for proper optical alignment with the intended path of the dye beam to be produced and for accurate pivotal movement relative to the beam path in order to function as a coarse tuning mechanism in the production of the ultimately tuned beam.

  16. Hair dryer use to optimize pulsed dye laser treatment in rosacea patients.

    PubMed

    Kashlan, Lana; Graber, Emmy M; Arndt, Kenneth A

    2012-06-01

    Rosacea is a common chronic inflammatory condition characterized by erythema, telangiectasias, papules, and pustules. While there are many effective treatment options for the papulopustular type, laser therapy remains the most effective modality to treat erythematotelangiectatic rosacea. Erythema and flushing associated with rosacea remains an uncomfortable and socially embarrassing problem for patients. Unfortunately, patients often do not have significant erythema or flushing when they present for laser treatment. With this in mind, we propose a novel technique aimed at enhancing the response of rosacea patients being treated for erythema with pulsed dye laser. Specifically, we present a split-face example of our clinical observation that pre-treatment with forced heated air prior to pulsed-dye laser leads to a greater response in rosacea patients with erythema and flushing.

  17. Preliminary results with dye-enhanced selective laser sclerosis of venous varicosities

    NASA Astrophysics Data System (ADS)

    Libutti, Steven K.; Oz, Mehmet C.; Chuck, Roy S. H.; Auteri, Joseph S.; Hibshoosh, Hanina; Nowygrod, Roman; Treat, Michael R.

    1990-06-01

    Laser sclerosis (photosclerosis) of veins after injection of wavelength-specific dyes to enhance and localize energy absorption could provide a useful adjunct to current treatment options. To enhance the absorption of 808nm diode laser energy, ear veins of 18 rabbits were infused with 2-3cc of indocyanine green (maximum absorption 805nm) and exposed for 2 to 20 seconds. Animals were sacrificed between 0 and 28 days after operation. Discrete time intervals of laser exposure exist during which various sized vessels can be photosclerosed without significant thermal injury to the overlying tissue. The use of low power, diode lasers, in conjunction with wavelength-specific dyes, may provide a simple, effective, and cosmetically appealling alternative to current treatment options for superficial varicosities of the extremities.

  18. High-average-power dye laser at Lawrence Livermore National Laboratory.

    PubMed

    Bass, I L; Bonanno, R E; Hackel, R P; Hammond, P R

    1992-11-20

    The copper-laser-pumped dye laser system developed at the Lawrence Livermore National Laboratory (LLNL) is now capable of sustained, efficient, and reliable operation at total powers exceeding 2500 W and single amplifier chain powers exceeding 1300 W. Wavelength center frequency stability is maintainable to < 50 MHz. Laser dyes developed at LLNL permit tunability from 550 to 650 nm. Wave-front quality is < lambda/4 peak to valley. The system is operated remotely with the aid of a comprehensive set of diagnostics. Besides supporting its primary atomic-vapor-laser-isotope-separation mission, the system is being used in alternate applications such as materials processing and the generation of artificial guide stars. PMID:20802559

  19. Morphological alterations on Citrobacter freundii bacteria induced by erythrosine dye and laser light.

    PubMed

    Silva, Josmary R; Cardoso, Gleidson; Maciel, Rafael R G; de Souza, Nara C

    2015-01-01

    The effect of the laser irradiation (532 nm) on films prepared from Citrobacter freundii mixed with erythrosine dye was investigated by using atomic force microscopy. It was observed that morphological changes of bacterial surfaces after irradiations, which were attributed to cellular damage of the outer membranes, are a result of a photodynamic effect. The results suggested that the combination of erythrosine and laser light at 532 nm could be a candidate to a photodynamic therapy against C. freundii.

  20. Leg veins with diameter between 1 and 3 mm: flash-lamp-pulsed dye laser, alexandrite laser, invasive Nd:YAG laser treatment, or sclerotherapy?

    NASA Astrophysics Data System (ADS)

    Smucler, Roman; Mazanek, Jiri; Moidlova, Marta

    2000-05-01

    After unrealistic laser expectations we can see renaissance of 'golden standard' -- sclerotherapy in leg veins treatment. Every laser specialist knows difference between facial and leg veins now. Combination of flash lamp pulsed dye laser /PDL/ and sclerotherapy can be new 'golden standard' but patients are dissatisfied with this procedure which include 'needle medicine.' We presented our way to solve this problem partially-invasive laser treatment with Nd:YAG laser last year. Another trend is introduction of new modifications of near infrared lasers. GentleLASE/Candela, MA/ with dynamic cooling is one of them. We treat veins from 0 - 1 mm in diameter very successfully with PDL/ScleroPlus, Candela, MA/, bigger veins we recommend for minimal invasive or classical surgery. Combination of lasers is we think only one possibility for successful laser treatment. Aim of our work is comparison of sclerotherapy with combinated treatments with PDL, near infrared laser and invasive Nd:YAG laser for veins in diameter between 1 - 2 mm. Results show that combination of lasers offer same results with comparable side effects like sclerotherapy that is cheaper and most common of course. Patients prefer pure laser therapy with combination of pulsed dye laser and alexandrite laser. We think that isn't one best method, decision is one the doctor and patient.

  1. Synchronous cavity mode and feedback wavelength scanning in dye laser oscillators with gratings.

    PubMed

    McNicholl, P; Metcalf, H J

    1985-09-01

    A simple result of scalar diffraction theory is used to derive the round trip phase accrual of a plane wave in dye laser oscillators containing gratings. This is used to determine configurations where the standing wave condition is satisfied at the feedback wavelength throughout an angle scan. We find that at least one such exactly synchronous configuration always exists regardless of oscillator type.

  2. Quantum beats in forward scattering - Subnanosecond studies with a mode-locked dye laser

    NASA Astrophysics Data System (ADS)

    Harde, H.; Burggraf, H.; Mlynek, J.; Lange, W.

    1981-06-01

    Time-resolved polarization spectroscopy of transient coherent superpositions of atomic substates is extended to the picosecond time scale by using a synchronously pumped mode-locked dye laser. As a first demonstration, hyperfine beats in the sodium D1 and D2 lines were resolved. The ground-state splitting could be determined with an accuracy of better than 0.001.

  3. Quantum beats in forward scattering: subnanosecond studies with a mode-locked dye laser.

    PubMed

    Harde, H; Burggraf, H; Mlynek, J; Lange, W

    1981-06-01

    Time-resolved polarization spectroscopy of transient coherent superpositions of atomic substates is extended to the picosecond time scale by using a synchronously pumped mode-locked dye laser. As a first demonstration, hyperfine beats in the sodium D(1) and D(2), lines were resolved. The ground-state splitting could be determined with an accuracy of better than 10(-3).

  4. Nonconfocal unstable resonator for solid-state dye lasers based on a gradient-reflectivity mirror

    SciTech Connect

    Chandra, S.; Allik, T.H.; Hutchinson, J.A.

    1995-12-01

    A compact high-brightness solid-state dye laser, consisting of a nonconfocal unstable resonator formed of a planar mirror and a gradient-reflectivity mirror, is modeled by use of ray-tracing analysis. Collimated 80-mJ output was obtained in a 10-mmmrad beam. {copyright} {ital 1995 Optical Society of America.}

  5. Ultrastructure: effects of melanin pigment on target specificity using a pulsed dye laser (577 nm)

    SciTech Connect

    Tong, A.K.; Tan, O.T.; Boll, J.; Parrish, J.A.; Murphy, G.F.

    1987-06-01

    It has been shown recently that brief pulses of 577 nm radiation from the tunable dye laser are absorbed selectively by oxyhemoglobin. This absorption is associated with highly specific damage to superficial vascular plexus blood vessels in those with lightly pigmented (type I-II) skin. To determine whether pigmentary differences in the overlying epidermis influence this target specificity, we exposed both type I (fair) and type V (dark) normal human skin to varying radiant exposure doses over 1.5-microsecond pulse durations from the tunable dye laser at a wavelength of 577 nm. Using ultrastructural techniques, we found in type I skin that even clinical subthreshold laser exposures caused reproducible alterations of erythrocytes and adjacent dermal vascular endothelium without comparable damage to the overlying epidermis. In contrast, degenerated epidermal basal cells represented the predominant form of cellular damage after laser exposure of type V skin at comparable doses. We conclude that epidermal melanin and vascular hemoglobin are competing sites for 577 nm laser absorption and damage, and that the target specificity of the 577 nm tunable dye laser is therefore influenced by variations in epidermal pigmentation. This finding is relevant to the clinical application of the tunable dye laser in the ablative treatment of vascular lesions. We also found on ultrastructure that the presence of electron-lucent circular structures of approximately 800 A in diameter were observed only at and above clinical threshold doses in those with type I skin and at the highest dose of 2.75 J/cm2 in type V skin. It has been proposed that these structures might be heat-fixed molds of water vapor. Both this and ultrastructural changes of epidermal basal cells demonstrate mechanisms responsible for alteration of tissue after exposure to 577 nm, which are discussed.

  6. Singlet oxygen scavengers affect laser-dye impairment of endothelium-dependent responses of brain arterioles.

    PubMed

    Rosenblum, W I; Nelson, G H

    1996-04-01

    This study investigates the possible role of singlet oxygen in accounting for the inhibitory effect of laser-dye injury on endothelium-dependent dilations. The combination of helium-neon (HeNe) laser (20-s exposure) and intravascular Evans blue impairs endothelium-dependent dilation of mouse pial arterioles by acetylcholine (ACh), bradykinin (BK), and calcium ionophore A23187. Each has a different endothelium-derived mediator (EDRFACh, EDRFBK, EDRFionophore, respectively). In this study, diameters at a craniotomy site were monitored in vivo with an image splitter-television microscope. The laser-dye injury, as usual, abolished the responses 10 and 30 min after injury, with recovery, complete or partial, at 60 min. Dilations by sodium nitroprusside, an endothelium-independent dilator, were not affected by laser-dye. When the singlet oxygen scavengers L-histidine (10(-3) M) and L-tryptophan (10(-2) M) were added to the suffusate over the site, the responses to ACh at 10 and 30 min were relatively intact, the response to BK was partly protected at 10 min only, and the response to ionophore was still totally impaired at 10 and 30 min. Lysine, a nonscavenging amino acid, had no protective effects with any dilator. We postulate that a heat-induced injury initiates a chain of events resulting in prolonged singlet oxygen generation by the endothelial cell (not by the dye). We postulate further that destruction of EDRFACh by singlet oxygen is responsible for laser-dye inhibition of ACh and that generation of the radical must continue for > or = 30 min. On the other hand, the heat injury itself is probably responsible for the elimination of the response to ionophore. Heat plus singlet oxygen generated by heat-damaged tissue may initially impair the response to BK, but by 30 min only the effects of some other factor, presumably heat injury, account for the impaired response to BK. PMID:8967364

  7. Tracheal anastomosis using indocyanine green dye enhanced fibrinogen with a near-infrared diode laser

    NASA Astrophysics Data System (ADS)

    Auteri, Joseph S.; Jeevanandam, Valluvan; Oz, Mehmet C.; Libutti, Steven K.; Kirby, Thomas J.; Smith, Craig R.; Treat, Michael R.

    1990-06-01

    A major obstacle to lung transplantation and combined heart- lung transplantation is dehiscence of the tracheobronchial anastomosis. We explored the possibility of laser welded anastomoses in canine tracheas in vivo. Laser anastomoses were performed on three-quarter circumferential anterior tracheotomies. A continous wave diode laser (808 +1 nm) at a power density of 9.6 watts/cm was used. Human fibrinogen was mixed with indocyanine green dye (ICG, max absorbance 805 nm) and applied to the anastomosis site prior to laser exposure. Animals were sacrificed at 0, 21 and 28 days post-operatively. At sacrifice weld bursting pressures were measured by raising intratracheal pressure using forced ventilation via an endotracheal tube. Sutured and laser welded anastomoses had similar bursting pressures, and exhibited satisfactory histologic evidence of healing. However, compared to polypropylene sutured controls, the laser welded anastomoses exhibited less peritracheal inflammatory reaction and showed visibly smoother luminal surfaces at 21 and 28 days post- operatively. Tracheal anastomosis using ICG dye enhanced fibrinogen combined with the near-infrared diode laser is a promising extension of the technology of laser tissue fusion and deserves further study.

  8. Detection of carcinogenic chromium in synthetic hair dyes using laser induced breakdown spectroscopy.

    PubMed

    Gondal, M A; Maganda, Y W; Dastageer, M A; Al Adel, F F; Naqvi, A A; Qahtan, T F

    2014-03-10

    A laser induced breakdown spectroscopic (LIBS) system, consisting of a pulsed 266 nm laser radiation, in conjunction with a high-resolution spectrograph, a gated intensified charge coupled device camera, and a built-in delay generator were used to develop a sensitive detector to quantify the concentration of toxic substances such as chromium in synthetic hair dyes available on the local market. The strong atomic transition line of chromium (Cr I) at 427.5 nm wavelength was used as a fingerprint wavelength to calibrate the detection system and also to quantify the levels of chromium in the hair dye samples. The limit of detection achieved by our LIBS detection system for chromium was 1.2 ppm, which enabled us to detect chromium concentration in the range of 5-11 ppm in the commercial hair dyes available on the local market. The concentrations of chromium in the hair dyes measured using our system were validated using a standard analytical technique such as inductively coupled plasma mass spectrometry (ICPMS), and acceptable agreement (nearly 8%) was found between the results obtained by the two methods (LIBS and ICPMS). This study is highly significant for human health, specifically for people using synthetic hair dyes for changing the color of their hair. PMID:24663421

  9. Direct Analysis of Textile Fabrics and Dyes Using IR Matrix-Assisted Laser Desorption Electrospray Ionization (MALDESI) Mass Spectrometry

    PubMed Central

    Cochran, Kristin H.; Barry, Jeremy A.; Muddiman, David C.; Hinks, David

    2012-01-01

    The forensic analysis of textile fibers uses a variety of techniques from microscopy to spectroscopy. One such technique that is often used to identify the dye(s) within the fiber is mass spectrometry (MS). In the traditional MS method, the dye must be extracted from the fabric and the dye components are separated by chromatography prior to mass spectrometric analysis. Direct analysis of the dye from the fabric allows the omission of the lengthy sample preparation involved in extraction, thereby significantly reducing the overall analysis time. Herein, a direct analysis of dyed textile fabric was performed using the infrared matrix-assisted laser desorption electrospray ionization (IR-MALDESI) source for MS. In MALDESI, an IR laser with wavelength tuned to 2.94 μm is used to desorb the dye from the fabric sample with the aid of water as the matrix. The desorbed dye molecules are then post-ionized by electrospray ionization (ESI). A variety of dye classes were analyzed from various fabrics with little to no sample preparation allowing for the identification of the dye mass and in some cases the fiber polymer. Those dyes that were not detected using MALDESI were also not observed by direct infusion ESI of the dye standard. PMID:23237031

  10. Direct analysis of textile fabrics and dyes using infrared matrix-assisted laser desorption electrospray ionization mass spectrometry.

    PubMed

    Cochran, Kristin H; Barry, Jeremy A; Muddiman, David C; Hinks, David

    2013-01-15

    The forensic analysis of textile fibers uses a variety of techniques from microscopy to spectroscopy. One such technique that is often used to identify the dye(s) within the fiber is mass spectrometry (MS). In the traditional MS method, the dye must be extracted from the fabric and the dye components are separated by chromatography prior to mass spectrometric analysis. Direct analysis of the dye from the fabric allows the omission of the lengthy sample preparation involved in extraction, thereby significantly reducing the overall analysis time. Herein, a direct analysis of dyed textile fabric was performed using the infrared matrix-assisted laser desorption electrospray ionization (IR-MALDESI) source for MS. In MALDESI, an IR laser with wavelength tuned to 2.94 μm is used to desorb the dye from the fabric sample with the aid of water as the matrix. The desorbed dye molecules are then postionized by electrospray ionization (ESI). A variety of dye classes were analyzed from various fabrics with little to no sample preparation allowing for the identification of the dye mass and in some cases the fiber polymer. Those dyes that were not detected using MALDESI were also not observed by direct infusion ESI of the dye standard. PMID:23237031

  11. Direct analysis of textile fabrics and dyes using infrared matrix-assisted laser desorption electrospray ionization mass spectrometry.

    PubMed

    Cochran, Kristin H; Barry, Jeremy A; Muddiman, David C; Hinks, David

    2013-01-15

    The forensic analysis of textile fibers uses a variety of techniques from microscopy to spectroscopy. One such technique that is often used to identify the dye(s) within the fiber is mass spectrometry (MS). In the traditional MS method, the dye must be extracted from the fabric and the dye components are separated by chromatography prior to mass spectrometric analysis. Direct analysis of the dye from the fabric allows the omission of the lengthy sample preparation involved in extraction, thereby significantly reducing the overall analysis time. Herein, a direct analysis of dyed textile fabric was performed using the infrared matrix-assisted laser desorption electrospray ionization (IR-MALDESI) source for MS. In MALDESI, an IR laser with wavelength tuned to 2.94 μm is used to desorb the dye from the fabric sample with the aid of water as the matrix. The desorbed dye molecules are then postionized by electrospray ionization (ESI). A variety of dye classes were analyzed from various fabrics with little to no sample preparation allowing for the identification of the dye mass and in some cases the fiber polymer. Those dyes that were not detected using MALDESI were also not observed by direct infusion ESI of the dye standard.

  12. Characterization of Pyrromethene-BF2-Complexes as laser dyes

    NASA Astrophysics Data System (ADS)

    Davenport, Wayne E.; Ehrlich, John J.; Neister, S. E.

    This paper compares the dye service lifetimes, slope efficiencies, tuning curves, and output energies of two Pyrromethene-BF2-Complexes to that of Rhodamine 590 Chloride. Service lifetimes were tested with and without the addition of caffeine as a UV filter. Due to the reported low triplet state absorption, the flashlamp pulse-widths were varied from two microseconds to ten microseconds in an effort to detect its presence.

  13. Efficient sintering of nanocrystalline titanium dioxide films for dye solar cells via raster scanning laser

    NASA Astrophysics Data System (ADS)

    Mincuzzi, Girolamo; Vesce, Luigi; Reale, Andrea; Di Carlo, Aldo; Brown, Thomas M.

    2009-09-01

    By identifying the right combination of laser parameters, in particular the integrated laser fluence Φ, we fabricated dye solar cells (DSCs) with UV laser-sintered TiO2 films exhibiting a power conversion efficiency η =5.2%, the highest reported for laser-sintered devices. η is dramatically affected by Φ and a clear trend is reported. Significantly, DSCs fabricated by raster scanning the laser beam to sinter the TiO2 films are made as efficient as those with oven-sintered ones. These results, confirmed on three batches of cells, demonstrate the remarkable potential (noncontact, local, low cost, rapid, selective, and scalable) of scanning laser processing applied to DSC technology.

  14. Optical Features of Spherical Gold Nanoparticle-Doped Solid-State Dye Laser Medium

    NASA Astrophysics Data System (ADS)

    Hoa, D. Q.; Lien, N. T. H.; Duong, V. T. T.; Duong, V.; An, N. T. M.

    2016-05-01

    The development of a new laser medium based on gold nanoparticle/dye-doped polymethylmethacrylate (PMMA) has been investigated. In particular, gold nanoparticles with small (16 nm diameter) spherical shape strongly influenced the absorption and fluorescence emission spectra of [2-[2-[4-(dimethylamino)phenyl]ethenyl]-6-methyl-4 H-pyran-4-ylidene]-propanedinitrile (DCM) laser dye. Fluorescence quenching and enhancement of DCM emission were observed for various concentrations of gold nanoparticles (GNPs). Fluorescence intensity enhancement was recorded for the sample containing 1.5 × 1010 par/mL GNPs and doped with 3 × 10-5 mol/L DCM. Thermal photodegradation was significantly decreased by using low pump energy for laser emission.

  15. Techniques for reducing and/or eliminating secondary modes in a dye laser oscillator

    DOEpatents

    Hackel, Richard P.

    1988-01-01

    A dye laser master oscillator is disclosed herein. This oscillator is intended to provide a single mode output, that is, a primary beam of light of a specific wavelength, but also has the tendency to provide secondary modes, that is, secondary beams of light at different wavelengths and slightly off-axis with respect to the primary beam as a result of grazing incident reflections within the dye cell forming part of the master oscillator. Also disclosed herein are a number of different techniques for reducing or eliminating these secondary modes.

  16. Time-resolved spectroscopy of laser emission from dye-doped droplets.

    PubMed

    Biswas, A; Latifi, H; Armstrong, R L; Pinnick, R G

    1989-02-15

    Micrometer-sized droplets of Rhodamine 6G solution in water and ethanol are irradiated by high-intensity nanosecond pulses from a frequency-doubled Nd:YAG laser. Coupling of the spontaneous fluorescence emission with natural resonant modes of the spherical droplets results in stimulated emission, with each droplet behaving like a laser cavity. Spectral observations suggest that droplet lasing emission is supported by resonances of a single mode order. The emission exhibits faster rise times and is shorter lived than corresponding bulk-liquid fluorescence. Lasing in droplets is generally initiated almost simultaneously with elastic scattering, unlike stimulated Raman scattering, which is significantly delayed.

  17. The perylene derivative BASF-241 solution as a new tunable dye laser in the visible

    NASA Astrophysics Data System (ADS)

    Ivri, J.; Burshtein, Z.; Miron, E.; Reisfeld, R.; Eyal, M.

    1990-09-01

    Basic optical properties of the perylene derivative BASF-241 solution in chloroform relevant to its application as a dye laser were measured. The fluorescence spectrum, excited by frequency-doubled (532-nm) Nd:YAG laser pulses, shows three pronounced peaks centered at 540, 580, and 630 nm, with a Stokes shift and mirror image in relation to the absorption spectrum. The quantum yield was about a unity, with a lifetime of 5.0 +/- 0.5 ns. Addition of trichloroacetic acid (CCl3COOH) causes a red shift of absorption and fluorescence spectra by about 750/cm-L/mol. In a cavity consisting of a about 100 percent reflecting back mirror and an 8 percent reflecting output coupler, lasing was obtained at 577 nm, with a threshold of about 10 micro-J/pulse, and a slope efficiency of about 8 percent. Medium losses were attributed to excited singlet-singlet absorption of cross section 1-2 x 10 to the -16th sq cm. Using a grating, a tuning range of almost 20 nm was obtained, centered at the 0-1 fluorescence emission peak. The laser range shifted to the red when the dye was dissolved in chloroform with an increasing concentration of trichloroacetic acid. The BASF-241 solution in chloroform thus appears to be a new, promising material for a dye laser.

  18. Improvements in laser flare removal for particle image velocimetry using fluorescent dye-doped particles

    NASA Astrophysics Data System (ADS)

    Petrosky, B. J.; Lowe, K. T.; Danehy, P. M.; Wohl, C. J.; Tiemsin, P. I.

    2015-11-01

    Laser flare, or scattering of laser light from a surface, can often be a major issue in particle image velocimetry (PIV) involving solid boundaries in the flow or a gas-liquid interface. The use of fluorescent light from dye-doped particles has been demonstrated in water applications, but reproducing the technique in an airflow is more difficult due to particle size constraints and safety concerns. The following work presents fluorescent Kiton Red 620 (KR620)-doped polystyrene latex microspheres as a solution to this issue. The particles are small and narrowly distributed, with a mean diameter of 0.87 μ \\text{m} and diameter distribution standard deviation of 0.30 μ \\text{m} . Furthermore, the KR620 dye exhibits much lower toxicity than other common fluorescent dyes, and would be safe to use in large flow facilities. The fluorescent signal from the particles is measured on average to be 320  ±  10 times weaker than the Mie scattering signal from the particles. This reduction in signal is counterbalanced by greatly enhanced contrast via optical rejection of the incident laser wavelength. Fluorescent PIV with these particles is shown to eliminate laser flare near surfaces, allowing for velocity measurements as close as 100 μ \\text{m} to the surface. In one case, fluorescent PIV led to velocity vector validation rates more than 20 times that of the Mie scattering results in the boundary layer region of an angled surface.

  19. Nanoforest Nb2O5 Photoanodes for Dye-Sensitized Solar Cells by Pulsed Laser Deposition

    SciTech Connect

    Ghosh, Rudresh; Brennaman, Kyle M.; Uher, Tim; Ok, Myoung-Ryul; Samulski, Edward T.; McNeil, L. E.; Meyer, Thomas J.; Lopez, Rene

    2011-10-26

    Vertically aligned bundles of Nb₂O₅ nanocrystals were fabricated by pulsed laser deposition (PLD) and tested as a photoanode material in dye-sensitized solar cells (DSSC). They were characterized using scanning and transmission electron microscopies, optical absorption spectroscopy (UV–vis), and incident-photon-to-current efficiency (IPCE) experiments. The background gas composition and the thickness of the films were varied to determine the influence of those parameters in the photoanode behavior. An optimal background pressure of oxygen during deposition was found to produce a photoanode structure that both achieves high dye loading and enhanced photoelectrochemical performance. For optimal structures, IPCE values up to 40% and APCE values around 90% were obtained with the N₃ dye and I₃{sup –}/I{sup –} couple in acetonitrile with open circuit voltage of 0.71 V and 2.41% power conversion efficiency.

  20. Broadband coherent anti-Stokes Raman spectroscopy with a modeless dye laser.

    PubMed

    Hahn, J W; Park, C W; Park, S N

    1997-09-20

    We develop a modeless dye laser for broadband coherent anti-Stokes Raman spectroscopy (CARS) and investigate the operational characteristics of the modeless laser. The energy efficiency of the modeless laser is 6%, and the beam divergence is 0.65 mrad. We construct a compact movable CARS system with the modeless laser and a graphite tube furnace to assess the accuracy of the CARS temperature. It is found that the difference between the averaged CARS temperature and the radiation temperature measured with an optical pyrometer is <2% at a temperature range from 1000 to 2400 K. We also measure the averaged CARS temperature drift owing to the variation of the spectral distribution of the modeless laser, which is <1.5% during 5 h of operation. PMID:18259536

  1. Intracavity absorption with a continuous wave dye laser: quantification for a narrowband absorber.

    PubMed

    Brobst, W D; Allen, J E

    1987-09-01

    Although it is recognized as a very sensitive detection technique, the general application of intracavity absorption to areas such as chemical kinetics and photochemistry has been somewhat limited. Concerns are frequently expressed about the nonlinear nature, experimental difficulty, and reliability of the technique. To allay some of these objections, the dependence of intracavity absorption on factors such as transition strength, concentration, absorber path length, and pump power has been investigated experimentally for a cw dye laser with a narrowband absorber (NO(2)). For this case a Beer-Lambert type relationship has been confirmed over a useful range of these parameters. The extent of intracavity absorption was quantitatively measured directly from the dye laser spectral profiles and, when compared to extracavity measurements, indicated enhancements as high as 12,000 for pump powers near lasing threshold. By defining an intracavity absorption coefficient, it was possible to demonstrate the reliability of the method by obtaining accurate transition strength ratios.

  2. Refractometric monitoring of dissolution and fluid flow with distributed feedback dye laser sensor.

    PubMed

    Vannahme, Christoph; Sørensen, Kristian Tølbøl; Gade, Carsten; Dufva, Martin; Kristensen, Anders

    2015-03-01

    Monitoring the dissolution of solid material in liquids and monitoring of fluid flow is of significant interest for applications in chemistry, food production, medicine, and especially in the fields of microfluidics and lab on a chip. Here, real-time refractometric monitoring of dissolution and fast fluid flow with DFB dye laser sensors with an optical imaging spectroscopy setup is presented. The dye laser sensors provide both low detection limits and high spatial resolution. It is demonstrated how the materials NaCl, sucrose, and bovine serum albumin show characteristic dissolution patterns. The unique feature of the presented method is a high frame rate of up to 20 Hz, which is proven to enable the monitoring of fast flow of a sucrose solution jet into pure water.

  3. Intracavity absorption with a continuous wave dye laser: quantification for a narowband absorber

    SciTech Connect

    Brobst, W.D.; Allen J.E. Jr.

    1987-09-01

    Although it is recognized as a very sensitive detection technique, the general application of intracavity absorption to areas such as chemical kinetics and photochemistry has been somewhat limited. Concerns are frequently expressed about the nonlinear nature, experimental difficulty, and reliability of the technique. To allay some of these objections, the dependence of intracavity absorption on factors such as transition strength, concentration, absorber path length, and pump power has been investigated experimentally for a cw dye laser with a narrowband absorber (NO/sub 2/). For this case a Beer-Lambert type relationship has been confirmed over a useful range of these parameters. The extent of intracavity absorption was quantitatively measured directly from the dye laser spectral profiles and, when compared to extracavity measurements, indicated enhancements as high as 12,000 for pump powers near lasing threshold. By defining an intracavity absorption coefficient, it was possible to demonstrate the reliability of the method by obtaining accurate transition strength ratios.

  4. Semiclassical theory of dye lasers: the single-frequency and multifrequency steady states of operation

    SciTech Connect

    Fu, H.; Haken, H.

    1988-05-01

    A semiclassical theory of dye lasers is presented in which the relevant energy-level diagram of a dye molecule is assumed to consist of a bandlike ground state with many sublevels and an excited single state. This theory not only describes the single-frequency operation, which has a low instability threshold, but also describes the two-frequency and multifrequency steady states of operation and the transitions between the different steady states. The general solution of a multifrequency operation is given explicitly and differs essentially from the well-known Rabi oscillation. The theoretical predictions are in good agreement with recent experiments done by Hillman et al. (Phys. Rev. Lett. 52, 1605 (1984)), which cannot be explained by the conventional Maxwell--Bloch laser theory derived from two-level atoms.

  5. Argon-pumped tunable dye laser for port-wine stains

    NASA Astrophysics Data System (ADS)

    Teillac-Hamel, Dominique; de Prost, Yves

    1994-12-01

    We have been using a continuous dye laser (coherent medical) for more than two years. The wavelength is 585 nm, the power 1.8 W and the fluence 16 - 18 J/cm2. We have treated 364 patients with port-wine stains and 15 children with ulcerated hemangiomas. The results were analyzed using a computer program developed by a team in Lille. The most frequent color was pale pink, followed by deep pink, red and purple. The mean number of laser sessions was 2.3.

  6. Non-degenerate two photon absorption enhancement for laser dyes by precise lock-in detection

    SciTech Connect

    Xue, B.; Katan, C.; Bjorgaard, J. A.; Kobayashi, T.

    2015-12-15

    This study demonstrates a measurement system for a non-degenerate two-photon absorption (NDTPA) spectrum. The NDTPA light sources are a white light super continuum beam (WLSC, 500 ∼ 720 nm) and a fundamental beam (798 nm) from a Ti:Sapphire laser. A reliable broadband NDTPA spectrum is acquired in a single-shot detection procedure using a 128-channel lock-in amplifier. The NDTPA spectra for several common laser dyes are measured. Two photon absorption cross section enhancements are found in the experiment and validated by theoretical calculation for all of the chromophores.

  7. Non-degenerate two photon absorption enhancement for laser dyes by precise lock-in detection

    NASA Astrophysics Data System (ADS)

    Xue, B.; Katan, C.; Bjorgaard, J. A.; Kobayashi, T.

    2015-12-01

    This study demonstrates a measurement system for a non-degenerate two-photon absorption (NDTPA) spectrum. The NDTPA light sources are a white light super continuum beam (WLSC, 500 ˜ 720 nm) and a fundamental beam (798 nm) from a Ti:Sapphire laser. A reliable broadband NDTPA spectrum is acquired in a single-shot detection procedure using a 128-channel lock-in amplifier. The NDTPA spectra for several common laser dyes are measured. Two photon absorption cross section enhancements are found in the experiment and validated by theoretical calculation for all of the chromophores.

  8. Singlet Oxygen and Dye-Triplet-State Quenching in Solid-State Dye Lasers Consisting of Pyrromethene 567 Doped Poly(Methyl Methacrylate)

    NASA Astrophysics Data System (ADS)

    Ahmad, Mohammad; Rahn, Mark D.; King, Terence A.

    1999-10-01

    Solid-state dye lasers based on poly(methyl methacrylate) (PMMA) doped with Pyrromethene 567 dye (P567) have been investigated. The preparation techniques employed provided high photostability and laser damage threshold for P567 in pure PMMA with 270,000 pulses emitted before the conversion efficiency fell to half its initial value for a pump fluence of 0.16 J cm 2 . When PMMA was modified with 1,4-diazobicyclo 2,2,2 octane singlet oxygen quencher, the longevity increased to 550,000 pulses, corresponding to a normalized photostability of 270 GJ mol 1 . Modification of PMMA with a triplet quencher (perylene) yielded no improvement, but in ethanol solutions both additives enhanced photostability. It is possible that in PMMA, stabilization by means of triplet quenching that depends on dye diffusion is prevented but that stabilization by means of singlet oxygen quenching that depends on the faster oxygen diffusion rate will succeed.

  9. Photophysical properties of lasing mixed solutions of oxazine 17 and rhodamine 6G

    SciTech Connect

    Levshin, L.V.; Saletskii, A.M.; Yuzhakov, V.I.

    1985-09-01

    This paper presents the results of the effect of triplet states of the donor component, for which Rhodamine 6G was used, on the lasing characteristics of lamp-pumped solutions of this dye, oxazine. The energy and spectral properties are studied and the results analyzed.

  10. Diagnosis of NMOS DRAM functional performance as affected by a picosecond dye laser

    NASA Technical Reports Server (NTRS)

    Kim, Q.; Schwartz, H. R.; Edmonds, L. D.; Zoutendyk, J. A.

    1992-01-01

    A picosec pulsed dye laser beam was at selected wavelengths successfully used to simulate heavy-ion single-event effects (SEEs) in negative channel NMOS DRAMs. A DRAM was used to develop the test technique because bit-mapping capability and previous heavy-ion upset data were available. The present analysis is the first to establish such a correlation between laser and heavy-ion data for devices, such as the NMOS DRAM, where charge collection is dominated by long-range diffusion, which is controlled by carrier density at remote distances from a depletion region. In the latter case, penetration depth is an important parameter and is included in the present analysis. A single-pulse picosecond dye laser beam (1.5 microns diameter) focused onto a single cell component can upset a single memory cell; clusters of memory cell upsets (multiple errors) were observed when the laser energy was increased above the threshold energy. The multiple errors were analyzed as a function of the bias voltage and total energy of a single pulse. A diffusion model to distinguish the multiple upsets from the laser-induced charge agreed well with previously reported heavy ion data.

  11. The influence of Ag nanoparticles on random laser from dye-doped nematic liquid crystals

    NASA Astrophysics Data System (ADS)

    Ye, Lihua; Liu, Bo; Li, Fangjie; Feng, Yangyang; Cui, Yiping; Lu, Yanqing

    2016-10-01

    The threshold energy and electric field response characteristic of random laser have been investigated in dye-doped nematic liquid crystal (DDNLC) with the addition of different concentrations of Ag nanoparticles (NPs). Due to the localized surface plasmon resonance (LSPR) induced by Ag NPs, random laser from DDNLC with Ag NP doping had a lower threshold energy. From another point of view, nematic liquid crystals (LCs) in a DDNLC cell with the addition of Ag NPs could be more easily influenced by the electric field, which allowed the random laser to be controlled at a lower applied voltage. The turn-off time and turn-on time of random laser also decreased in the DDNLC cells with increasing the concentration of Ag NPs. This is due to the enhancement of the electro-optical characteristic of LC and the restoring force imparted by the locally ordered LCs induced by the Ag NPs, respectively.

  12. Spectral and lasing characteristics of dye-doped cholesteric liquid crystals as materials for laser projection screens

    NASA Astrophysics Data System (ADS)

    Ilchishin, Igor P.

    2004-07-01

    Absorbtion spectra, fluorescence spectra and quantum yields of dyes of various classes in cholesteric liquid crystals (CLC) and in isotropic solutions as well as the thresholds oftheir lasing in CLC were investigated. The increase ofquantum yields of dyes in concentrated CLC-solution in comparison with diluted isotropic ones are established for the first time. It has been shown that neutral phenolenone dyes with voluminose terminal groups which hinder aggregation of their molecules in concentrated solutions. The experimental investigations of the lasing efficiency of a distributed feedback laser (DFB) based on CLC from excitation intensity and optical density of dye in the active layer are presented. The thermal phase grating induced by laser radiation in doped CLC, as it is shown, the high << effective Q>> of the CLC layers are compensated and the lasing efficiency ofthis lasers are improved.

  13. Laser inhibited diffusion in rhodamine-ethanol solutions

    NASA Technical Reports Server (NTRS)

    Lawandy, N. M.; Fuhr, P. L.; Robinson, D. W.

    1981-01-01

    The diffusion of rhodamine-6G dye in ethanol is observed to be inhibited by optical pumping by a cadmium laser. The diffusion process is observed as a function of the solution temperature. The relative difference in diffusion coefficients with and without optical pumping is calculated. The effect is interpreted as being due to a stronger solvent-dye interaction in the first excited singlet state of rhodamine-6G.

  14. Random lasing and coherent back scattering study in rhodamine 6G doped polymer optical fiber (POF) particles

    NASA Astrophysics Data System (ADS)

    C, Sreechandralijith K.; Peter, Jaison; Thankappan, Aparna; Nampoori, V. P. N.; Radhakrishnan, P.

    2014-10-01

    We demonstrate coherent back scattering and random lasing from an active random media of Rhodamine 6G doped polymer optical fiber particles on different sizes. Narrow emission modes are observed experimentally over a broad range of scattering strengths without requiring optical cavities. The particle-size dependence of transport mean free path, which measured from coherent backscattering measurements. Since the scattering mean free path is less than the emission wavelength, recurrent light scattering arises and provides coherent feedback for lasing. Laser emission from the sample observed in all directions. This observation also provides direct evidence for the existence of recurrent scattering of light. The lasing threshold intensity depends on the excitation volume, also the decrease of the lasing threshold at large particle size. The feedback for lasing originates mainly from backscattering of particles near the boundaries of the pumped region. Here, the lasing threshold depends strongly on the size distribution, dye concentration and intensity of excitation in the ensemble.

  15. Fiberized fluorescent dye microtubes

    NASA Astrophysics Data System (ADS)

    Vladev, Veselin; Eftimov, Tinko

    2013-03-01

    In the present work we study the effect of the length of fluorescent dye-filled micro-capillaries on the fluorescence spectra. Two types of micro-capillaries have been studied: a 100 μm inner diameter fused silica capillary with a transparent coating and one of the holes of a fiber optic glass ferrule with 125 μm inner diameter. The tubes were filled with solutions of Rhodamine 6G dissolved in ethanol and then in glycerin. Experimental data show that the maximum fluorescence and the largest spectral widths are observed for a sample length of about 0.25 mm for the used concentration. This results show that miniature tunable fiberized dye lasers can be developed using available standard micro-and fibre-optic components.

  16. Selective photothermal interaction using near-infrared laser and laser-absorbing dye in gel phantom and chicken breast tissue

    NASA Astrophysics Data System (ADS)

    Cowan, Thomas M.; Liu, Guangyu; Simmons, Sarah; Real, Jeremy; Lucroy, Michael D.; Bartels, Kenneth E.; Nordquist, Robert E.; Chen, Wei R.

    2002-06-01

    Photothermal interaction of an 805-nm diode laser with an absorptive dye, indocyanine green (ICG), has been shown to be an efficacious therapy for metastatic breast tumors in a rat model when combined with immunoadjuvant. When ICG solution was injected into the target tissue, selective tissue destruction can be achieved. To study the selective photothermal interaction, temperature change in irradiated tissue was achieved. To study the selective photothermal interaction, temperature change in irradiated tissue was studied using chicken breast tissue and phantom composed of gelatin and intralipid. ICG solution was mixed with gel phantom to simulate dye-enhanced target tissue. The target gel was then embedded in chicken breast tissue. The temperature change of irradiated chicken and gel phantom was measured by needle temperature probes at different tissue depths and radii from the center of the laser beam to construct a two-dimensional array of temperature change in a cylindrical coordinate system. It was shown that it is possible to selectively raise the temperature of deep target tissue while not substantially heating nontargeted tissue. A Nd:YAG laser was also used to irradiate the tissue-gel system and the photothermal results were compared with that using the 805-nm laser.

  17. Feasibility study: Monodisperse polymer particles containing laser-excitable dyes

    NASA Technical Reports Server (NTRS)

    Venkateswarlu, Putcha; He, K. X.; Sharma, A.

    1993-01-01

    The optical properties associated with small particles, which include aerosols, hydrosols and solid microspheres have an impact on several areas of science and engineering. Since the advent of high-speed computers and lasers, the interaction of light with matter in the form of small particles with a discontinuous optical boundary relative to the surroundings has been much better understood. Various nonlinear optical effects have been observed involving interaction of a laser beam with both solid microspheres and liquid microdroplets. These include observation of second and third harmonic generation, four wave mixing, optical visibility, two photon absorption, observation of stimulated emission and lasing, and Stimulated Raman Scattering. Many of these effects are observed with laser intensities which are orders of magnitude less than that required by threshold condition for interactions in macroscopic bulk medium. The primary reason for this is twofold. The front surface of the microsphere acts as a thick lens to enhance the internal intensity of the input laser radiation, and the spherical shape of the droplet acts as an optical cavity to provide feedback at specific wavelengths corresponding to the whispering gallery modes or the morphology dependent resonances (MDR's). The most interesting and significant recent finding in this field is undoubtedly the existence of resonance peaks in linear and nonlinear optical spectra. Such resonance peaks are only dependent on the particle morphology, which means the size, shape and refractive index of the particle. Because of the simultaneous presence of these resonances, they have been referred to by many names, including structural resonances, whispering modes or whispering gallery modes, creeping waves, circumferential waves, surfaces modes, and virtual modes. All of these names refer to the same phenomena, i.e. morphology dependent resonances (MDR's) which has already been described and predicted precisely by

  18. From Dye Laser Factory to Portable Semiconductor Laser: Four Generations of Sodium Guide Star Lasers for Adaptive Optics in Astronomy and Space Situational Awareness

    NASA Astrophysics Data System (ADS)

    d'Orgeville, C.; Fetzer, G.

    This presentation recalls the history of sodium guide star laser systems used in astronomy and space situational awareness adaptive optics, analysing the impact that sodium laser technology evolution has had on routine telescope operations. While it would not be practical to describe every single sodium guide star laser system developed to date, it is possible to characterize their evolution in broad technology terms. The first generation of sodium lasers used dye laser technology to create the first sodium laser guide stars in Hawaii, California, and Spain in the late 1980's and 1990's. These experimental systems were turned into the first laser guide star facilities to equip medium-to-large diameter adaptive optics telescopes, opening a new era of LGS AO-enabled diffraction-limited imaging from the ground. Although they produced exciting scientific results, these laser guide star facilities were large, power-hungry and messy. In the USA, a second-generation of sodium lasers was developed in the 2000's that used cleaner, yet still large and complex, solid-state laser technology. These are the systems in routine operation at the 8-10m class astronomical telescopes and 4m-class satellite imaging facilities today. Meanwhile in Europe, a third generation of sodium lasers was being developed using inherently compact and efficient fiber laser technology, and resulting in the only commercially available sodium guide star laser system to date. Fiber-based sodium lasers will be deployed at two astronomical telescopes and at least one space debris tracking station this year. Although highly promising, these systems remain significantly expensive and they have yet to demonstrate high performance in the field. We are proposing to develop a fourth generation of sodium lasers: based on semiconductor technology, these lasers could provide the final solution to the problem of sodium laser guide star adaptive optics for all astronomy and space situational awareness applications.

  19. Enhancement of the stability of a synchronously excited cw dye laser by insertion of a nonlinear absorber

    SciTech Connect

    Gafurov, K.G.; Krindach, D.P.; Nekhaenko, V.A.; Yakovlev, A.G.

    1985-06-01

    An experimental investigation was made of combined mode locking of a cw laser utilizing a mixture of rhodamine 6G (amplifier) and malachite green (absorber). The action of a saturable absorber shortened the output pulses to 700 fsec, widened the range of existence of the short pulses, and appreciably increased the lasing stability compared with synchronous excitation of pure rhodamine 6G. These characteristics of the radiation of a laser with combined mode locking were associated with the saturation dynamics of the gain and the absorption.

  20. Portable IR dye laser optofluidic microresonator as a temperature and chemical sensor.

    PubMed

    Lahoz, F; Martín, I R; Gil-Rostra, J; Oliva-Ramirez, M; Yubero, F; Gonzalez-Elipe, A R

    2016-06-27

    A compact and portable optofluidic microresonator has been fabricated and characterized. It is based on a Fabry-Perot microcavity consisting essentially of two tailored dichroic Bragg mirrors prepared by reactive magnetron sputtering deposition. The microresonator has been filled with an ethanol solution of Nile-Blue dye. Infrared laser emission has been measured with a pump threshold as low as 0.12 MW/cm2 and an external energy conversion efficiency of 41%. The application of the device as a temperature and a chemical sensor is demonstrated. Small temperature variations as well as small amount of water concentrations in the liquid laser medium are detected as a shift of the resonant laser modes. PMID:27410592

  1. High efficiency picosecond pulse generation in the 675-930 nm region from a dye laser synchronously pumped by an argon-ion laser. Technical report

    SciTech Connect

    Bado, P.; Dupuy, C.; Wilson, K.R.; Boggy, R.; Bowen, J.

    1983-04-01

    Picosecond pulses tunable from 675 to 930 micrometers have been obtained from a dye-laser synchronously pumped at 514.5 micrometers by a mode-locked Argon-ion laser. Peak energy conversion efficiencies between 10% and 29% are observed with pulse durations between 1.7 ps and 16 ps as measured by autocorrelation.

  2. Large fluctuations at the lasing threshold of solid- and liquid-state dye lasers

    NASA Astrophysics Data System (ADS)

    Basak, Supratim; Blanco, Alvaro; López, Cefe

    2016-08-01

    Intensity fluctuations in lasers are commonly studied above threshold in some special configurations (especially when emission is fed back into the cavity or when two lasers are coupled) and related with their chaotic behaviour. Similar fluctuating instabilities are usually observed in random lasers, which are open systems with plenty of quasi-modes whose non orthogonality enables them to exchange energy and provides the sort of loss mechanism whose interplay with pumping leads to replica symmetry breaking. The latter however, had never been observed in plain cavity lasers where disorder is absent or not intentionally added. Here we show a fluctuating lasing behaviour at the lasing threshold both in solid and liquid dye lasers. Above and below a narrow range around the threshold the spectral line-shape is well correlated with the pump energy. At the threshold such correlation disappears, and the system enters a regime where emitted laser fluctuates between narrow, intense and broad, weak peaks. The immense number of modes and the reduced resonator quality favour the coupling of modes and prepares the system so that replica symmetry breaking occurs without added disorder.

  3. Large fluctuations at the lasing threshold of solid- and liquid-state dye lasers

    PubMed Central

    Basak, Supratim; Blanco, Alvaro; López, Cefe

    2016-01-01

    Intensity fluctuations in lasers are commonly studied above threshold in some special configurations (especially when emission is fed back into the cavity or when two lasers are coupled) and related with their chaotic behaviour. Similar fluctuating instabilities are usually observed in random lasers, which are open systems with plenty of quasi-modes whose non orthogonality enables them to exchange energy and provides the sort of loss mechanism whose interplay with pumping leads to replica symmetry breaking. The latter however, had never been observed in plain cavity lasers where disorder is absent or not intentionally added. Here we show a fluctuating lasing behaviour at the lasing threshold both in solid and liquid dye lasers. Above and below a narrow range around the threshold the spectral line-shape is well correlated with the pump energy. At the threshold such correlation disappears, and the system enters a regime where emitted laser fluctuates between narrow, intense and broad, weak peaks. The immense number of modes and the reduced resonator quality favour the coupling of modes and prepares the system so that replica symmetry breaking occurs without added disorder. PMID:27558968

  4. Large fluctuations at the lasing threshold of solid- and liquid-state dye lasers.

    PubMed

    Basak, Supratim; Blanco, Alvaro; López, Cefe

    2016-01-01

    Intensity fluctuations in lasers are commonly studied above threshold in some special configurations (especially when emission is fed back into the cavity or when two lasers are coupled) and related with their chaotic behaviour. Similar fluctuating instabilities are usually observed in random lasers, which are open systems with plenty of quasi-modes whose non orthogonality enables them to exchange energy and provides the sort of loss mechanism whose interplay with pumping leads to replica symmetry breaking. The latter however, had never been observed in plain cavity lasers where disorder is absent or not intentionally added. Here we show a fluctuating lasing behaviour at the lasing threshold both in solid and liquid dye lasers. Above and below a narrow range around the threshold the spectral line-shape is well correlated with the pump energy. At the threshold such correlation disappears, and the system enters a regime where emitted laser fluctuates between narrow, intense and broad, weak peaks. The immense number of modes and the reduced resonator quality favour the coupling of modes and prepares the system so that replica symmetry breaking occurs without added disorder. PMID:27558968

  5. Large fluctuations at the lasing threshold of solid- and liquid-state dye lasers.

    PubMed

    Basak, Supratim; Blanco, Alvaro; López, Cefe

    2016-08-25

    Intensity fluctuations in lasers are commonly studied above threshold in some special configurations (especially when emission is fed back into the cavity or when two lasers are coupled) and related with their chaotic behaviour. Similar fluctuating instabilities are usually observed in random lasers, which are open systems with plenty of quasi-modes whose non orthogonality enables them to exchange energy and provides the sort of loss mechanism whose interplay with pumping leads to replica symmetry breaking. The latter however, had never been observed in plain cavity lasers where disorder is absent or not intentionally added. Here we show a fluctuating lasing behaviour at the lasing threshold both in solid and liquid dye lasers. Above and below a narrow range around the threshold the spectral line-shape is well correlated with the pump energy. At the threshold such correlation disappears, and the system enters a regime where emitted laser fluctuates between narrow, intense and broad, weak peaks. The immense number of modes and the reduced resonator quality favour the coupling of modes and prepares the system so that replica symmetry breaking occurs without added disorder.

  6. Use of reflectance spectrophotometry to predict the response of port wine stains to pulsed dye laser.

    PubMed

    Halachmi, Shlomit; Azaria, Ron; Inbar, Roy; Ad-El, Dean; Lapidoth, Moshe

    2014-01-01

    Reflectance spectroscopy can be used to quantitate subtle differences in color. We applied a portable reflectance spectrometer to determine its utility in the evaluation of pulsed dye laser treatment of port wine stains (PWS) and in prediction of clinical outcome, in a prospective study. Forty-eight patients with PWS underwent one to nine pulsed dye laser treatments. Patient age and skin color as well as PWS surface area, anatomic location, and color were recorded. Pretreatment spectrophotometric measurements were performed. The subjective clinical results of treatment and the quantitative spectrophotometry results were evaluated by two independent teams, and the findings were correlated. The impact of the clinical characteristics on the response to treatment was assessed as well. Patients with excellent to good clinical results of laser treatments had pretreatment spectrophotometric measurements which differed by more than 10%, whereas patients with fair to poor results had spectrophotometric measurements with a difference of of less than 10%. The correlation between the spectrophotometric results and the clinical outcome was 73% (p < 0.01). The impact of the other clinical variables on outcome agreed with the findings in the literature. Spectrophotometry has a higher correlation with clinical outcome and a better predictive value than other nonmeasurable, nonquantitative, dependent variables.

  7. Argon laser phototherapy of human malignancies using rhodamine-123 as a new laser dye: The intracellular role of oxygen

    SciTech Connect

    Castro, D.J.; Saxton, R.E.; Markley, J.; Foote, C.S.; Fetterman, H.R.; Castro, D.J.; Ward, P.H. )

    1990-08-01

    Recent studies demonstrated that the cationic, mitochondrial-specific dye Rhodamine-123 (Rh-123), is an efficient tumor photosensitizer for Argon laser treatment of human cancer cells both in vitro and in tumors grown as xenografts in athymic mice. To demonstrate the photodynamic mechanism of action of this reaction, the intracellular role of oxygen and temperature changes in treated cells have to be defined. In the current study, a large panel of human tumor cell lines of diverse histologic origin were tested for in vitro sensitivity to Rh-123 and the Argon laser (514.5 nm) in oxygen, deuterium oxide (D2O), and nitrogen (N2) environment. Tumor cells in suspension were first sensitized to Rh-123 (1 or 20 micrograms/ml for 1 hour), cooled on ice to 4 degrees C, and then exposed to the Argon laser (delta T = 14 +/- 1 degree C). Cell proliferation measured by (3H)-thymidine uptake 24 hours after sensitization with Rh-123 and laser treatment was significantly decreased in tumor cells kept in oxygen and D2O atmospheres. No decrease in DNA synthesis was seen in Rh-123 and laser treated cells kept in an N2 environment. Control tumor cells treated with Rh-123 or the Argon laser separately did not show any decreased (3H)-thymidine uptake in oxygen, D2O or N2 environment. These results provide evidence of a photodynamic process since Rh-123 sensitization and Argon laser activation occur at nonthermal levels of energy and are oxygen dependent. The high effectiveness of this technique of photodynamic therapy with the Argon laser, and low toxicity of Rh-123 could make its clinical use very attractive for the treatment of superficial malignancies.

  8. Experience with the pulsed dye laser in management of ureteric calculi.

    PubMed

    Bolton, D M; Peters, J S; Costello, A J

    1992-10-01

    Pulsed dye laser lithotripsy is a recently developed technique for the management of urinary calculi. This article reports the results of treatment of a cohort of patients managed with this technology. Post-treatment bed stay was generally less than 48 h, narcotic analgesia was not regularly required, and no significant post-treatment complications were encountered. This treatment appeared to complement an existing extracorporeal shockwave lithotripsy (ESWL) service at St Vincent's Hospital and may offer a financial advantage in the treatment of patients with urinary calculi.

  9. Selective fluorescence functionalization of dye-doped polymerized structures fabricated by direct laser writing (DLW) lithography

    NASA Astrophysics Data System (ADS)

    de Miguel, Gustavo; Vicidomini, Giuseppe; Duocastella, Martí; Diaspro, Alberto

    2015-11-01

    The continuous development of the vast arsenal of fabrication techniques is a pivotal factor in the breakthrough of nanotechnology. Although the broad interest is generally focused on the reduction of the dimensions of the fabricated structures, localized functionalization of the nanomaterials emerges as a key factor closely linked to their potential applications. In particular, fabrication of spatially selective fluorescence nanostructures is highly demanded in nanophotonics, as for example in three-dimensional (3D) optical data storage (ODS), where massive storage capacity and fast writing-reading processes are promised. We have developed an innovative method to control the location and intensity of the fluorescence signal in dye-doped photopolymerized structures fabricated with Direct Laser Writing (DLW) lithography. Well-defined fluorescent pixels (area = 0.24 μm2) were written inside a polymer matrix with the help of a femtosecond pulsed laser (multiphoton absorption) via a thermally-induced di-aggregation of a fluorescent dye. Moreover, we have accomplished a fine control of the fluorescence intensity which can increase the storage capacity of ODS systems fabricated with this approach.The continuous development of the vast arsenal of fabrication techniques is a pivotal factor in the breakthrough of nanotechnology. Although the broad interest is generally focused on the reduction of the dimensions of the fabricated structures, localized functionalization of the nanomaterials emerges as a key factor closely linked to their potential applications. In particular, fabrication of spatially selective fluorescence nanostructures is highly demanded in nanophotonics, as for example in three-dimensional (3D) optical data storage (ODS), where massive storage capacity and fast writing-reading processes are promised. We have developed an innovative method to control the location and intensity of the fluorescence signal in dye-doped photopolymerized structures fabricated

  10. A review of the quality of life following pulsed dye laser treatment for erythemotelangiectatic rosacea.

    PubMed

    Bonsall, Alexandra; Rajpara, Sanjaykumar

    2016-01-01

    Rosacea is a chronic condition, affecting up to 10% of the population. It has a negative impact on patients' quality of life (QOL), leading to loss of self-confidence, emotional distress and withdrawal from normal societal interactions. Erythemotelangiectatic (ET) rosacea is a frequent reason for consultation and difficult to treat, as vascular signs such as flushing, erythema and telangiectasia often persist despite medical therapy. Several studies have demonstrated objective improvements in vascular signs following pulsed dye laser (PDL) treatment, but very few have investigated improvement in QOL. We reviewed the current literature to find evidence for the effect of PDL on QOL in ET rosacea. PMID:26836241

  11. Emission Lifetimes of a Fluorescent Dye under Shock Compression.

    PubMed

    Liu, Wei-long; Bassett, Will P; Christensen, James M; Dlott, Dana D

    2015-11-01

    The emission lifetimes of rhodamine 6G (R6G) were measured under shock compression to 9.1 GPa, with the dual intents of better understanding molecular photophysics in extreme environments and assessing the usefulness of fluorescence lifetime microscopy to measure spatially dependent pressure distributions in shocked microstructured media. R6G was studied as free dye dissolved in poly(methyl methacrylate) (PMMA), or dye encapsulated in silica microparticles suspended in PMMA. Thin layers of these materials in impedance-matched geometries were subjected to planar single-stage shocks created by laser-driven flyer plates. A synchronized femtosecond laser excited the dye at selected times relative to flyer plate arrival and the emission lifetimes were measured with a streak camera. Lifetimes decreased when shocks arrived. The lifetime decrease was attributed to a shock-induced enhancement of R6G nonradiative relaxation. At least part of the relaxation involved shock-enhanced intersystem crossing. For free dye in PMMA, the lifetime decrease during the shock was shown to be a linear function of shock pressure from 0 to 9 GPa, with a slope of -0.22 ns·GPa(-1). The linear relationship makes it simple to convert lifetimes into pressures. Lifetime measurements in shocked microenvironments may be better than emission intensity measurements, because lifetimes are sensitive to the surrounding environment, but insensitive to intensity variations associated with the motion and optical properties of a dynamically changing structure.

  12. Emission Lifetimes of a Fluorescent Dye under Shock Compression.

    PubMed

    Liu, Wei-long; Bassett, Will P; Christensen, James M; Dlott, Dana D

    2015-11-01

    The emission lifetimes of rhodamine 6G (R6G) were measured under shock compression to 9.1 GPa, with the dual intents of better understanding molecular photophysics in extreme environments and assessing the usefulness of fluorescence lifetime microscopy to measure spatially dependent pressure distributions in shocked microstructured media. R6G was studied as free dye dissolved in poly(methyl methacrylate) (PMMA), or dye encapsulated in silica microparticles suspended in PMMA. Thin layers of these materials in impedance-matched geometries were subjected to planar single-stage shocks created by laser-driven flyer plates. A synchronized femtosecond laser excited the dye at selected times relative to flyer plate arrival and the emission lifetimes were measured with a streak camera. Lifetimes decreased when shocks arrived. The lifetime decrease was attributed to a shock-induced enhancement of R6G nonradiative relaxation. At least part of the relaxation involved shock-enhanced intersystem crossing. For free dye in PMMA, the lifetime decrease during the shock was shown to be a linear function of shock pressure from 0 to 9 GPa, with a slope of -0.22 ns·GPa(-1). The linear relationship makes it simple to convert lifetimes into pressures. Lifetime measurements in shocked microenvironments may be better than emission intensity measurements, because lifetimes are sensitive to the surrounding environment, but insensitive to intensity variations associated with the motion and optical properties of a dynamically changing structure. PMID:26469397

  13. Raman spectroscopy of organic dyes adsorbed on pulsed laser deposited silver thin films

    NASA Astrophysics Data System (ADS)

    Fazio, E.; Neri, F.; Valenti, A.; Ossi, P. M.; Trusso, S.; Ponterio, R. C.

    2013-08-01

    The results of a surface-enhanced Raman scattering (SERS) study performed on representative organic and inorganic dyes adsorbed on silver nanostructured thin films are presented and discussed. Silver thin films were deposited on glass slides by focusing the beam from a KrF excimer laser (wavelength 248 nm, pulse duration 25 ns) on a silver target and performing the deposition in a controlled Ar atmosphere. Clear Raman spectra were acquired for dyes such as carmine lake, garanza lake and brazilwood overcoming their fluorescence and weak Raman scattering drawbacks. UV-visible absorption spectroscopy measurements were not able to discriminate among the different chromophores usually referred as carmine lake (carminic, kermesic and laccaic acid), as brazilwood (brazilin and brazilein) and as garanza lake (alizarin and purpurin). SERS measurements showed that the analyzed samples are composed of a mixture of different chromophores: brazilin and brazilein in brazilwood, kermesic and carminic acid in carmine lake, alizarin and purpurin in garanza lake. Detection at concentration level as low as 10-7 M in aqueous solutions was achieved. Higher Raman intensities were observed using the excitation line of 632.8 nm wavelength with respect to the 785 nm, probably due to a pre-resonant effect with the molecular electronic transitions of the dyes.

  14. Sentinel Lymph Node Detection Using Laser-Assisted Indocyanine Green Dye Lymphangiography in Patients with Melanoma

    PubMed Central

    Jain, Vikalp; Phillips, Brett T.

    2013-01-01

    Introduction. Sentinel lymph node (SLN) biopsy is a vital component of staging and management of multiple cancers. The current gold standard utilizes technetium 99 (tech99) and a blue dye to detect regional nodes. While the success rate is typically over 90%, these two methods can be inconclusive or inconvenient for both patient and surgeon. We evaluated a new technique using laser-assisted ICG dye lymphangiography to identify SLN. Methods. In this retrospective analysis, we identified patients with melanoma who were candidates for SLN biopsy. In addition to tech99 and methylene blue, patients received a dermal injection of indocyanine green (ICG). The infrared signal was detected with the SPY machine (Novadaq), and nodes positive by any method were excised. Results. A total of 15 patients were evaluated, with 40 SLNs removed. Four patients were found to have nodal metastases on final pathology. 100% of these 4 nodes were identified by ICG, while only 75% (3/4) were positive for tech99 and/or methylene blue. Furthermore, none of the nodes missed by ICG (4/40) had malignant cells. Conclusion. ICG dye lymphangiography is a reasonable alternative for locating SLNs in patients with melanoma. Prospective studies are needed to better ascertain the full functionality of this technique. PMID:24382997

  15. Long-term wavelength drift compensation of tunable pulsed dye laser for sodium detection lidar

    NASA Astrophysics Data System (ADS)

    Xia, Yuan; Cheng, Xuewu; Li, Faquan; Wang, Jihong; Yang, Yong; Lin, Xin; Gong, Shunsheng

    2015-11-01

    Wavelength stabilization for a pulsed laser presents more challenges than that of continuous wave laser. We have developed a simple and efficient long-term wavelength drifts compensation technique for tunable pulsed dye lasers (PDL) applied in sodium detection lidar system. Wavelength calibration and locking are implemented by using optogalvanic (OG) spectroscopy in a Na hollow cathode lamp (HCL) in conjunction with a digital control software. Optimization of OG signals for better laser wavelength discrimination and feedback control is performed. Test results indicate that locking the multimode broadband PDL to the Na atomic transition corresponding to 589.158 nm is well achieved although the temperature in the laboratory is unstable. Through active compensation, the maximum wavelength drift is reduced from over 5 pm to 0.42 pm in 10 h and the maximum wavelength drift rate of the PDL is improved from 3.3 pm/h to 0.3 pm/h. It has been used to efficient sodium resonance fluorescence lidar detection. This technique is economical and easy to implement, and it provides flexible wavelength control and allows generalization for some other applications which require the wavelength of tunable pulsed lasers to be fixed at an atomic resonance transition references.

  16. Transient absorption in water-micellar solutions of rhodamine 6G with flash lamp excitation

    SciTech Connect

    Levin, M.B.; Cherkasov, A.S.

    1986-06-01

    This paper studies the kinetics of transient losses in water-micellar solutions of rhodamine 6G by using flash lamp excitation. During the experiments, the laser radiation energy was measured, the time evolution of stimulated emission spectra was recorded; pulse shape was monitored by an oscillograph. The change of generation characteristics of water-micellar solutions of rhodamine 6G as a function of cyclooctatetraene concentration is shown.

  17. Use of Tunable, Pulsed Dye Laser for Quantitative Fluorescence in Syphilis Serology (FTA-ABS Test)

    PubMed Central

    Kasatiya, S. S.; Lambert, N. G.; Laurence, R. A.

    1974-01-01

    A pulsed dye laser was used as an excitation source in a fluorescent treponemal antibody absorption (FTA-ABS) test. A high precision in quantitative fluorescence was obtained with this high-power excitation source coupled to an electronic detection system and a storage oscilloscope by standardization of fluorescence evaluation and through elimination of human error. One 0.4-μs pulse exposure was sufficient to record fluorescence intensity data on the oscilloscope. Absence of fading of fluorescence after repeated excitation permitted multiple readings of the same microscope field. Almost 100% reproducible results were obtained for the FTA-ABS test with 40 samples. Electronic detection of fluorescence and the high sensitivity obtained with laser excitation raise doubts about the relative value of quantitative immunofluorescence in the FTA-ABS test. PMID:4598221

  18. Enhancement of KTP/532 laser disc decompression and arthroscopic microdiscectomy with a vital dye

    NASA Astrophysics Data System (ADS)

    Yeung, Anthony T.

    1993-07-01

    Currently, the clinical indications and results of arthroscopic microdiscectomy and laser disc decompression come close to, but do not exceed, the results of classic discectomy or microdiscectomy for the whole spectrum of surgical disc herniations. However, as minimally invasive techniques continue to evolve, results can be expected to equal or be potentially superior to conventional surgery. This exhibit demonstrates how the use of a vital dye can enhance standard arthroscopic microdiscectomy techniques and, when used in conjunction with KTP/532 laser disc decompression, allows for better arthroscopic visualization, documentation, and extraction of nucleus pulposus, ultimately expanding the current limiting criteria for minimally invasive techniques. When proper patient selection is combined with good clinical indications, the surgical results are rather dramatic, often achieving immediate relief of sciatica in the operating room.

  19. Effectiveness of the Pulse Dye Laser Treatment in a Caucasian Women With Dermatosis Papulosa Nigra.

    PubMed

    Karadag, Ayse Serap; Ozkanli, Şeyma; Mansuroglu, Cem; Ozlu, Emin; Zemheri, Ebru

    2015-01-01

    Dermatosis papulosa nigra (DPN) is a group of superficial, benign papules commonly in African-American and Asian persons. DPN is considered to be a form of seborrheic keratosis with a specific localization and it is less frequently described in the white population. Treatment modalities include cryosurgery, curettage, electrosurgery, shave removal, and different laser treatment. Pulsed dye laser (PDL) has traditionally been used to treat vascular lesions, but it has been shown to be effective in treatment of lentigines, ephelides, seborrheic keratosis, and rarely DPN. A 43-year-old white female presents with a 5 year-old history of hyperpigmented papules on malar region, neck and upper trunk. The patient is diagnosed with DPN based on her clinical and histopathological findings. The PDL treatment was used successfully. In our opinion PDL is an effective alternative cure option for DPN. PMID:26120179

  20. Random lasing from Rhodamine 6G doped ethanediol solution based on the cicada wing nanocones

    NASA Astrophysics Data System (ADS)

    Zhang, Hua; Feng, Guoying; Zhang, Hong; Yang, Chao; Yin, Jiajia; Dai, Shenyu; Zhou, Shouhuan

    2016-06-01

    Random lasing from Rhdomaine 6G (Rh6G) doped ethanediol solution based on the cicada wing nanostructures as scatterers has been demonstrated. The optical positive feedback of the random laser is provided by these nanocones on the cicada wing, where the scale of the nanocones and the distance between them is about 150 nm and 200 nm, respectively. Al-coated reflector has been introduced to reduce the loss of the pump energy from the bottom, and moreover lower the laser threshold, which is about 126.0 μJ/pulse. Due to the liquid gain medium, the lifetime of this random laser is longer than conventional random lasers. This random laser shows the potential applications in biological random laser and photonic devices.

  1. Photophysical parameters and fluorescence quenching of 7-diethylaminocoumarin (DEAC) laser dye

    NASA Astrophysics Data System (ADS)

    El-Mossalamy, E. H.; Obaid, A. Y.; El-Daly, S. A.

    2011-10-01

    The optical properties including electronic absorption spectrum, emission spectrum, fluorescence quantum yield, and dipole moment of electronic transition of 7-diethylaminocoumarin (DEAC) laser dye have been measured in different solvents. Both electronic absorption and fluorescence spectra are red shifted as the polarity of the medium increases, indicating that the dipole moment of molecule increases on excitation. The fluorescence quantum yield of DEAC decreases as the polarity of solvent increases, a result of the role of solvent polarity in stabilization of the twisting of the intramolecular charge transfer (TICT) in excited state, which is a non-emissive state, as well as hydrogen bonding with the hetero-atom of dye. The emission spectrum of DEAC has also been measured in cationic (CTAC) and anionic (SDS) micelles, the intensity increases as the concentration of surfactant increases, and an abrupt change in emission intensity is observed at critical micelle concentration (CMC) of surfactant. 2×10 -3 mol dm -3 of DEAC gives laser emission in the blue region on pumping with nitrogen laser ( λex=337.1 nm). The laser parameters such as tuning range, gain coefficient ( α), emission cross section ( σe), and half-life energy have been calculated in different solvents, namely acetone, dioxane , ethanol, and dimethyforamide (DMF). The photoreactivity of DEAC has been studied in CCl 4 at a wavelength of 366 nm. The values of photochemical yield ( ϕc) and rate constant ( k) are determined. The interaction of organic acceptors such as picric acid (PA), tetracyanoethylene (TCNE), and 7,7,8,8-tetracynoquinonedimethane (TCNQ) with DEAC is also studied using fluorescence measurements in acetonitrile (CH 3CN); from fluorescence quenching study we assume the possible electron transfer from excited donor DEAC to organic acceptor forming non-emissive exciplex.

  2. Early results of pulsed dye laser angioplasty with integral ball-tips in long femoral occlusions

    NASA Astrophysics Data System (ADS)

    Murray, Alan; Mitchell, David C.; Wood, Richard F. M.

    1990-07-01

    A Pulsed Dye laser together with specifically designed integral ball-tipped optical fibres have been used for the primary recanalisation of femoropopliteal vascular disease in 25 limbs of 23 patients. All patients had complete occlusions of the vessels ranging from 8-49cms in length (mean 22cms), having presented with critical ischaemia (18) or severe claudication warranting operative intervention (5). Pedal ulceration was present in 8 limbs and digital gangrene in 4. The laser produced visible light at 480nm in lOOmJ/lus pulses, at a frequency of 10-20Hz. The energy delivery device comprised a smooth atraumatic ball-tip constructed from the glass of the optical fibre, which was loaded retrogradely into a standard balloon angioplasty catheter. The device was introduced through a common femoral artery cutdown. Angiographic recanalisation was achieved in 22 of the 25 limbs with a mean energy of 280J(range 68-727J) and in each case the channel created by the laser fibre was augmented by balloon angioplasty. Technical failure occurred in three cases, caused by a wall dissection, persistent side-branch entry and incomplete lesion penetration respectively. Eighteen of procedures (72%) were clinically successful with marked symptomatic improvement. Of the four angiographic successful but clinical failures, acute occlusion within 48 hours occurred in 2 diabetic patients with very poor run-off and distal gangrene. The third case failed acutely due to a technically inadequate balloon dilatation and the fourth patient failed to improve symptomatically due to widespread with segmental tibial vessel disease below a successful recanalisation. Over a mean follow-up period of 7 months, three patients died of myocardial infarction. Twelve of the 23 patients (52%) remain well with patent vessels. These early results demonstrate the efficacy of pulsed dye laser angioplasty using ball-tipped optical fibres.

  3. Effect of relaxation processes on fluorescence lifetime and polarization characteristics of rhodamine 6G in glycerol

    SciTech Connect

    Levshin, L.V.; Struganova, I.A.; Tolevtaev, B.N.

    1986-11-01

    Some new phenomena which can be attributed to the relaxation kinetics of the distribution halfwidth over the 0-0 frequencies for organic dye solutions have been discovered in the present work. The kinetic and polarization characteristics of flourescence from the viscous dipolar solutions of the dyes exhibiting dynamic inhomogeneous broadening upon excitation near the absorption band center have been studied. The objects of the study are rhodamine 6G solutions in glycerol and ethanol at the concentration 10/sup -//sub 6/ mole/liter. It was concluded that the presence of the dip in the flourescence lifetime and the hump in the fluorescence polarization dependences on emission wavelength in the viscous dipolar solution of rhodamine 6G has been detected. The phenomena have been explained by the formation of the excited-state nonequilibrium distribution of the flourescence centers over the 0-0 transition frequencies upon monochromatic excitation and by the subsequent relaxation of the nonequilibrium distribution into the equilibrium one.

  4. Selective fluorescence functionalization of dye-doped polymerized structures fabricated by direct laser writing (DLW) lithography.

    PubMed

    de Miguel, Gustavo; Vicidomini, Giuseppe; Duocastella, Martí; Diaspro, Alberto

    2015-12-21

    The continuous development of the vast arsenal of fabrication techniques is a pivotal factor in the breakthrough of nanotechnology. Although the broad interest is generally focused on the reduction of the dimensions of the fabricated structures, localized functionalization of the nanomaterials emerges as a key factor closely linked to their potential applications. In particular, fabrication of spatially selective fluorescence nanostructures is highly demanded in nanophotonics, as for example in three-dimensional (3D) optical data storage (ODS), where massive storage capacity and fast writing-reading processes are promised. We have developed an innovative method to control the location and intensity of the fluorescence signal in dye-doped photopolymerized structures fabricated with Direct Laser Writing (DLW) lithography. Well-defined fluorescent pixels (area = 0.24 μm(2)) were written inside a polymer matrix with the help of a femtosecond pulsed laser (multiphoton absorption) via a thermally-induced di-aggregation of a fluorescent dye. Moreover, we have accomplished a fine control of the fluorescence intensity which can increase the storage capacity of ODS systems fabricated with this approach. PMID:26572098

  5. Semiclassical dye-laser equations and the unidirectional single-frequency operation

    SciTech Connect

    Fu, H.; Haken, H.

    1987-11-15

    A semiclassical description for dye lasers is proposed, where the energy-level diagram of the dye molecule is assumed to consist of a continuous bandlike ground state and an excited singlet state. Unidirectional single-frequency (s.f.) operation is discussed. The linear-stability analysis for this operation reveals a very low threshold instability, which may appear generally in practical lasers. The ratio of the instability threshold to the lasing threshold may be of any value greater than 1, depending mainly on the bandwidth and the distribution of the dipole moments on the band, but it is independent of the cavity loss. This instability may account for that observed in recent experiments by Hillman, Krasinki, Boyd, and Stroud (Phys. Rev. Lett. 52, 1605 (1984)). A general approach to analyzing the linear stability of the s.f. operation of the Maxwell-Bloch equations is also proposed, which states that only the eigenvalues of a 2 x 2 matrix are relevant: one concerns the stability of the s.f. operation near the lasing threshold, the other determines the instability threshold of this operation.

  6. Direct solar-pumped iodine laser amplifier

    NASA Technical Reports Server (NTRS)

    Han, Kwang S.; Kim, K. H.; Stock, L. V.

    1986-01-01

    In order to evaluate the feasibility of the solar pumped dye laser, the parametric study of a dye laser amplifier pumped by a solar simulator and flashlamp was carried out, and the amplifier gains were measured at various pump beam irradiances on the dye cell. Rhodamine 6G was considered as a candidate for the solar pumped laser because of its good utilization of the solar spectrum and high quantum efficiency. The measurement shows that a solar concentration of 20,000 is required to reach the threshold of the dye. The work to construct a kinetic model algorithm which predicts the output parameter of laser was progressed. The kinetic model was improved such that there is good agreement between the theoretical model and experimental data for the systems defined previously as flashlamp pumped laser oscillator, and the long path length solar pumped laser.

  7. Enhanced fluorescence emitted by microdroplets containing organic dye emulsions.

    PubMed

    Boni, M; Nastasa, V; Andrei, I R; Staicu, Angela; Pascu, M L

    2015-01-01

    In this paper, laser beam resonant interaction with pendant microdroplets that are seeded with a laser dye (Rhodamine 6G (Rh6G)) water solution or oily Vitamin A emulsion with Rhodamine 6G solution in water is investigated through fluorescence spectra analysis. The excitation is made with the second harmonic generated beam emitted by a pulsed Nd:YAG laser system at 532 nm. The pendant microdroplets containing emulsion exhibit an enhanced fluorescence signal. This effect can be explained as being due to the scattering of light by the sub-micrometric drops of oily Vitamin A in emulsion and by the spherical geometry of the pendant droplet. The droplet acts as an optical resonator amplifying the fluorescence signal with the possibility of producing lasing effect. Here, we also investigate how Rhodamine 6G concentration, pumping laser beam energies and number of pumping laser pulses influence the fluorescence behavior. The results can be useful in optical imaging, since they can lead to the use of smaller quantities of fluorescent dyes to obtain results with the same quality. PMID:25784965

  8. Preliminary clinical results of pulsed-dye laser therapy for recurrent respiratory papillomatosis

    NASA Astrophysics Data System (ADS)

    McMillan, Kathleen; Shapshay, Stanley M.; McGilligan, J. A.; Wang, Zhi; Rebeiz, Elie E.

    1998-07-01

    Recurrent respiratory papillomatosis (RRP) is a viral disease characterized by the growth of benign tumors on the vocal cords. Standard management of RRP currently consists of CO2 laser microsurgical ablation of the papillomas. Because of the recurrent nature of this disease, patients are often faced with significant cumulative risk of soft tissue complications such as vocal cord scarring. As a minimally traumatic alternative to management of RRP, we have investigated the use of the 585 nm pulsed dye laser (PDL) to cause regression of the papillomas by selective eradication of the tumor microvasculature. Three patients have been treated with the PDL at fluences of 6 J/cm2 (double pulses per irradiated site), 8 J/cm2 (single pulses), and 10 J/cm2 (single pulses), at noncritical areas within the larynx, using a specially designed micromanipulator. Lesions on the true cords were treated with the CO2 laser. Clinical examination showed that PDL treatment appeared to produce complete regression of papillomas. Unlike the sites of lesions treated by the CO2 laser, the epithelial surface at the PDL treatment sites was preserved intact. The presumed mechanism for papilloma regression following PDL treatment involves acute or chronic localized hypoxia caused by loss of tumor microvasculature.

  9. Optimal dye concentration and power density for laser-assisted vascular anatomosis (LAVA)

    NASA Astrophysics Data System (ADS)

    Ren, Zhen; Furnary, Anthony; Xie, Hua; Lagerquist, Kathryn A.; Burke, Allen; Prahl, Scott A.; Gregory, Kenton W.

    2003-06-01

    Laser tissue welding with albumin solder/indocyanine green (ICG) dye is an effective technique in surgical reconstruction. This study was carried out in vitro to find optimal ICG concentration and power density (PD) in laser assisted vascular anastomosis (LAVA). Fresh porcine carotid arteries incised into vascular strips (n = 120) were welded by diode laser in end-to-end with 50% albumin solder of 0.01, 0.1, and 1.0 mM ICG and at power density of 27.7, 56.7, and 76.9 W/cm2. Direct temperature was measured by inserting thermocouples outside and inside vessel. Tensile strength was tested immediately and histological study was performed. Temperature (both outside and inside vessel) significantly gradually decreasd (p < 0.01) with the increasing of ICG concentration at PD 56.7 W/cm2. Tensile strength significantly gradually decreased (p < 0.01) with increasing of ICG concentration at PD 56.7 W/cm2. Histological study showed minimal thermal injury limited to adventitia of vessels and no appreciable difference in all groups. We find that ICG concentration within solder is most important factor affecting both tissue temperature and tensile strength during laser vessel welding. The optimal balance between stronger strength and minimal thermal injury of vessel may be achieved primarily by using PD 56.7 W/cm2 at 0.01 mM ICG within solder during LAVA.

  10. Enhanced efficiency of the dye-sensitized solar cells by excimer laser irradiated carbon nanotube network counter electrode

    SciTech Connect

    Chien, Yun-San Fu, Wei-En; Yang, Po-Yu; Lee, I-Che; Chu, Chih-Chieh; Chou, Chia-Hsin; Cheng, Huang-Chung

    2014-02-03

    The carbon nanotube network decorated with Pt nanoparticles (PtCNT) irradiated by excimer laser as counter electrode (CE) of dye-sensitized solar cells (DSSCs) has been systematically demonstrated. The conversion efficiency would be improved from 7.12% to 9.28% with respect to conventional Pt-film one. It was attributed to the enhanced catalytic surface from Pt nanoparticles and the improved conductivity due to the adjoining phenomenon of PtCNTs irradiated by laser. Moreover, the laser annealing could also promote the interface contact between CE and conductive glass. Therefore, such a simple laser-irradiated PtCNT network is promising for the future flexible DSSCs applications.

  11. Generation of intense 10-ps, 193-nm pulses using simple distributed feedback dye lasers and an ArF(*) amplifier.

    PubMed

    Hatten, D L; Cui, Y; Iii, W T; Mikes, T; Goldhar, J

    1992-11-20

    A pair of holographic distributed feedback dye lasers is used to generate 10-ps pulses at two selected wavelengths that are mixed in a BBO crystal to produce a pulse ~ 10 ps in duration at 193 nm. This seed pulse is subsequently amplified in an ArF(*) excimer laser to an energy of 10-15 mJ with <40 microJ in amplified spontaneous emission. The pulses are nearly transform limited and diffraction limited.

  12. Surface-enhanced Raman spectroscopy on laser-engineered ruthenium dye-functionalized nanoporous gold

    NASA Astrophysics Data System (ADS)

    Schade, Lina; Franzka, Steffen; Biener, Monika; Biener, Jürgen; Hartmann, Nils

    2016-06-01

    Photothermal processing of nanoporous gold with a microfocused continuous-wave laser at λ = 532 nm provides a facile means in order engineer the pore and ligament size of nanoporous gold. In this report we take advantage of this approach in order to investigate the size-dependence of enhancement effects in surface-enhanced Raman spectroscopy (SERS). Surface structures with laterally varying pore sizes from 25 nm to ≥200 nm are characterized using scanning electron microscopy and then functionalized with N719, a commercial ruthenium complex, which is widely used in dye-sensitized solar cells. Raman spectroscopy reveals the characteristic spectral features of N719. Peak intensities strongly depend on the pore size. Highest intensities are observed on the native support, i.e. on nanoporous gold with pore sizes around 25 nm. These results demonstrate the particular perspectives of laser-fabricated nanoporous gold structures in fundamental SERS studies. In particular, it is emphasized that laser-engineered porous gold substrates represent a very well defined platform in order to study size-dependent effects with high reproducibility and precision and resolve conflicting results in previous studies.

  13. Chitosan, nanoclay and chitosan-nanoclay composite as adsorbents for Rhodamine-6G and the resulting optical properties.

    PubMed

    Vanamudan, Ageetha; Pamidimukkala, Padmaja

    2015-03-01

    The objective of this study was to investigate the use of chitosan-clay nanocomposite (CC) as an adsorbent for Rhodamine 6G (Rh-6G). The effects of adsorbent dose, contact time, and concentration on the adsorption process were systematically studied. Isotherm models were applied to the experimental equilibrium data obtained from spectrophotometric measurements of dye adsorption. Various Kinetic models were used to describe the kinetic data and evaluate of rate constants. Rh-6G loaded adsorbents were investigated for their optical and photophysical properties. PMID:25526692

  14. Combined Treatment with Botulinum Toxin and 595-nm Pulsed Dye Laser for Traumatic Scarring.

    PubMed

    Lee, Sang Ju; Jeong, Se Yeong; No, Yeon A; Park, Kui Young; Kim, Beom Joo

    2015-12-01

    Traumatic scars on skin covering areas of high movement, especially areas on the face, can be stressful for patients. We report two cases of traumatic scars that occurred on the chin, and that were successfully treated with a combined therapy of 595-nm pulsed dye laser (PDL) and intramuscular injection of botulinum toxin. After the treatment, good cosmetic results were achieved in both patients. The only adverse effect during and after the treatments was mild pain, which resolved within several days without any additional treatment. In conclusion, the combination of 595-nm PDL and intramuscular botulinum toxin injection was shown to be a safe and effective treatment for traumatic scars on the mobile chin area in Korean patients. PMID:26719648

  15. Spectroscopic studies of biologically active coumarin laser dye: Evaluation of dipole moments by solvatochromic shift method

    NASA Astrophysics Data System (ADS)

    Koppal, V. V.; Muddapur, G. V.; Patil, N. R.; Melavanki, R. M.

    2016-05-01

    In this paper we attempted to record absorption and emission spectra of 2-acetyl-3H-benzo[f]chromen-3-one [2AHBC] laser dye in different solvents of varying polarities to investigate its solvatochromic behavior. The two electronic states dipole moments of 2AHBC are calculated using solvatochromic spectral shifts which are correlated with dielectric constant (ɛ) refractive index (n) of various solvents. A systematic approach is made to estimate ground and excited state dipole moments on the basis of different solvent correlation methods like Bilot-Kawski equations, Lippert-Mataga, Bakhsheiv, Kawaski-Chamma-Viallet and Reichardt methods. Dipole moments in the excited state was found to be higher than the ground state by confirming π→π* transition.

  16. Combined CW ring single-frequency Ti:sapphire/dye laser for atom cooling and high-precision spectroscopy

    NASA Astrophysics Data System (ADS)

    Kobtsev, Sergey; Baraulya, Vladimir; Lunin, Vladimir

    2007-04-01

    Presented in the work are the results of the development of a new combined CW ring single-frequency laser with universal design that allows efficient use as the active medium of both a Ti:Sapphire crystal and a dye jet. For the first time such combination has been implemented in a horizontal resonator configuration that offers an improvement of stability in the position of optical elements and more convenient operation. The short-term line width without the frequency stabilisation is less than 5 MHz (Ti:Sapphire) and < 10 MHz (Dye); with the frequency stabilisation to a specially designed thermo-stabilised reference interferometer with high finesse, the line width is less than 10 kHz (Ti:Sapphire) and 90 kHz (Dye), output frequency drift being less than 25 MHz/hour. The total working spectral range of the combined laser stretches from 550 to 1000 nm (550-770 nm for the Dye and 695-1000 nm for Ti:Sapphire) when pumped with 532/515-nm radiation. The maximum output power with a 10-W pump exceeds 2 W for the Ti:Sapphire configuration and is > 1 .5 W for the Dye one.

  17. Polymer thin-film distributed feedback tunable lasers

    NASA Astrophysics Data System (ADS)

    Dumarcher, Vincent; Rocha, Licinio; Denis, Christine; Fiorini, Céline; Nunzi, Jean-Michel; Sobel, Frank; Sahraoui, Bouchta; Gindre, Denis

    2000-07-01

    We report on measurements of laser emission from poly-methylmethacrylate and poly-vinyl carbazole polymer films doped with rhodamine-6G, DCM and coumarin laser dyes in an optically pumped distributed feedback scheme. We obtain tunability on a broad spectral range for all samples. We show the impact of waveguiding in the polymer film on reducing the laser threshold. We also show that the number of laser modes increases with the polymer film thickness, following the guided mode dispersion.

  18. Nonconventional Use of Flash-Lamp Pulsed-Dye Laser in Dermatology.

    PubMed

    Nisticò, Steven; Campolmi, Piero; Moretti, Silvia; Del Duca, Ester; Bruscino, Nicola; Conti, Rossana; Bassi, Andrea; Cannarozzo, Giovanni

    2016-01-01

    Flash-lamp pulsed-dye laser (FPDL) is a nonablative technology, typically used in vascular malformation therapy due to its specificity for hemoglobin. FPDL treatments were performed in a large group of patients with persistent and/or recalcitrant different dermatological lesions with cutaneous microvessel involvement. In particular, 149 patients (73 males and 76 females) were treated. They were affected by the following dermatological disorders: angiokeratoma circumscriptum, genital and extragenital viral warts, striae rubrae, basal cell carcinoma, Kaposi's sarcoma, angiolymphoid hyperplasia, and Jessner-Kanof disease. They all underwent various laser sessions. 89 patients (59.7%) achieved excellent clearance, 32 patients (21.4%) achieved good-moderate clearance, 19 patients (12.7%) obtained slight clearance, and 9 subjects (6.1%) had low or no removal of their lesion. In all cases, FPDL was found to be a safe and effective treatment for the abovementioned dermatological lesions in which skin microvessels play a role in pathogenesis or development. Further and single-indication studies, however, are required to assess a standardized and reproducible method for applying this technology to "off-label" indications. PMID:27631010

  19. Nonconventional Use of Flash-Lamp Pulsed-Dye Laser in Dermatology

    PubMed Central

    Del Duca, Ester; Bruscino, Nicola; Conti, Rossana; Cannarozzo, Giovanni

    2016-01-01

    Flash-lamp pulsed-dye laser (FPDL) is a nonablative technology, typically used in vascular malformation therapy due to its specificity for hemoglobin. FPDL treatments were performed in a large group of patients with persistent and/or recalcitrant different dermatological lesions with cutaneous microvessel involvement. In particular, 149 patients (73 males and 76 females) were treated. They were affected by the following dermatological disorders: angiokeratoma circumscriptum, genital and extragenital viral warts, striae rubrae, basal cell carcinoma, Kaposi's sarcoma, angiolymphoid hyperplasia, and Jessner-Kanof disease. They all underwent various laser sessions. 89 patients (59.7%) achieved excellent clearance, 32 patients (21.4%) achieved good-moderate clearance, 19 patients (12.7%) obtained slight clearance, and 9 subjects (6.1%) had low or no removal of their lesion. In all cases, FPDL was found to be a safe and effective treatment for the abovementioned dermatological lesions in which skin microvessels play a role in pathogenesis or development. Further and single-indication studies, however, are required to assess a standardized and reproducible method for applying this technology to “off-label” indications. PMID:27631010

  20. Nonconventional Use of Flash-Lamp Pulsed-Dye Laser in Dermatology

    PubMed Central

    Del Duca, Ester; Bruscino, Nicola; Conti, Rossana; Cannarozzo, Giovanni

    2016-01-01

    Flash-lamp pulsed-dye laser (FPDL) is a nonablative technology, typically used in vascular malformation therapy due to its specificity for hemoglobin. FPDL treatments were performed in a large group of patients with persistent and/or recalcitrant different dermatological lesions with cutaneous microvessel involvement. In particular, 149 patients (73 males and 76 females) were treated. They were affected by the following dermatological disorders: angiokeratoma circumscriptum, genital and extragenital viral warts, striae rubrae, basal cell carcinoma, Kaposi's sarcoma, angiolymphoid hyperplasia, and Jessner-Kanof disease. They all underwent various laser sessions. 89 patients (59.7%) achieved excellent clearance, 32 patients (21.4%) achieved good-moderate clearance, 19 patients (12.7%) obtained slight clearance, and 9 subjects (6.1%) had low or no removal of their lesion. In all cases, FPDL was found to be a safe and effective treatment for the abovementioned dermatological lesions in which skin microvessels play a role in pathogenesis or development. Further and single-indication studies, however, are required to assess a standardized and reproducible method for applying this technology to “off-label” indications.

  1. A methodology for improving laser beam induced current images of dye sensitized solar cells

    NASA Astrophysics Data System (ADS)

    Navas, Francisco Javier; Alcántara, Rodrigo; Fernández-Lorenzo, Concha; Martín, Joaquín

    2009-06-01

    Using the laser beam induced current (LBIC) technique for the study of solar cells and photovoltaic devices, it is possible to obtain images representing the different degrees of quantum efficiency observed on the surface of these elements. Dye sensitized solar cells (DSSCs) or photoelectrochemical solar cells, in contrast to those based on solid-solid interfaces, show a slow response to irradiance variations—up to tens of seconds. This is basically due to both viscous matter transport processes and load transfer. This response is inappreciable when the device is functioning continuously but when a LBIC scan is performed, in which the laser moves quickly from one point to another, the slow response produces a memory effect and the signal generated at one given point depends on the conversion efficiency coefficients of the previously excited positions, resulting in diffuse images and a lack of sharpness. This work presents a methodology to correct high-resolution LBIC mappings of DSSCs using an algorithm based on the kinetics of the discharge process of the irradiated zone. The validity of the proposed method has been evaluated by carrying out experiments where the algorithm has been applied to LBIC mappings.

  2. Solar Lentigines: Evaluating Pulsed Dye Laser (PDL) as an Effective Treatment Option

    PubMed Central

    Ghaninejhadi, Hayedeh; Ehsani, Amirhooshang; Edrisi, Ladan; Gholamali, Fatemeh; Akbari, Zahra; Noormohammadpour, Pedram

    2013-01-01

    Introduction: Solar lentigines are among commonest cosmetic problems. There are many topical therapies suggested to treat these lesions including cryotherapy, chemical peeling with tri chloro acetic acid (TCA) and laser therapy with q-switched lasers as well as long pulsed lasers. Considering possible treatment side effects (PIH, scar) with cryotherapy and peeling in Iranian patients (darker skin types) it seems necessary to try to find alternative measures. The aim of the present study was to evaluate effect of long pulsed dye laser (LPDL) on lentigines via an objective method (computerized dermoscopy). Methods: Patients with pathologically confirmed lentigines were selected if they agreed to participate in the study,were not treated before, hadn’t history of psoriasis, vitiligo, scar formation and were not pregnant. Letigines were dermoscopied before and after treatment with PDL (V-beam, 595nm, Candela Corp. Wayland, USA) using fluence of 10 joules,without DCD (dynamic cooling device) via extra compress lens provided with laser system.The resulting figures were compared by two academic unrelated dermatologists as well as by computerized analysis. Post laser side effects were treated with topical antibiotics and mild topical steroids. Patients were followed for six months after the end of the study to determine the rate of recurrence via dermoscopy of sites of previous lesions and also delayed side effects. Results: A total of 21 patients with the same number of lesions, were included in the study.Mean age of patients was 54.2 years (±23.3) ranging from 39 to 71 years. Included patient swere 18 females and three males. From 21 treated lesions, 11 were located on the hands and 10 on the face. Comparing before and after photographs taken through dermoscopy system,revealed that approximately 57% of patients had more than 75% improvement. Mean pigment analysis score (calculated by computerized dermoscope software) was respectively 8 and 2 before and after PDL

  3. Laser-induced release of liposome-encapsulated dye to monitor tissue temperature: study of different liposome compositions

    NASA Astrophysics Data System (ADS)

    Desmettre, Thomas; Mordon, Serge R.; Devoisselle, Jean-Marie; Soulie-Begu, Sylvie

    1995-01-01

    This study aimed to evaluate the interest of several liposome compositions (DPPC, DSPC, DPPA) to control specific ranges of temperature and to assess the possible use of temperature sensitive liposomes in an established model such as the liver as a new approach to monitor tissue temperature under laser irradiation. Temperature sensitive liposomes (DPPC or DSPC or DPPA) loaded with carboxy-fluorescein were injected to Wistar rats. The liver was exposed and irradiated with a 100 W Nd:YAG laser (single pulse mode, pulses ranging from 100 to 260 ms, spot diameter: 4 mm) to avoid direct absorption by the dye entrapped in the liposomes. The temperature was measured with an infrared camera during laser irradiation. The animals were then sacrificed and the liver was surgically removed. Immediately after, the fluorescence was measured -- ex vivo -- with a fluorescent imaging system. We were not able to prepare stable high transition temperature liposomes (DPPE). Concerning DPPC, the mechanism of dye release at the basal temperature led to a complete leakage of the dye in less than 5 minutes. Only background fluorescence was observed but no specific response due to laser irradiation. Nevertheless the results obtained using DSPC liposomes meet to a large extent our requirements since a useful monitoring of temperature is feasible from 42 degree(s)C to 62 degree(s)C. In fact the critical temperature of most tissues varies from 53 degree(s)C to 58 degree(s)C.

  4. Investigation of Fluorescence Characteristic in Transversely Excited Dye and Nanoparticle-Doped PMMA Fibre

    NASA Astrophysics Data System (ADS)

    NG, C. S.; Yap, S. S.; Chin, O. H.; Wong, H. Y.; Tou, T. Y.

    2011-03-01

    A simple extruder was used to fabricate poly (methyl methacrylate) (PMMA) fibers with optimum diameter 0.5 mm from the modified, low-softening (50-60° C) PMMA that was prepared using the reactive polymerization. The laser dye Rhodamine 6G (R6G) and Zinc Oxide (ZnO) nanoparticles of nominal diameter 30nm were added to the monomer MMA prior to the polymerization process, hence producing a random media. The nanoparticle embedded dye-doped PMMA fibers were transversely excited by TEA Nitrogen (N2) laser for fluorescence studies. It was observed that ZnO nanoparticles embedded in the dye-doped PMMA fibre significantly improved the fluorescence characteristic.

  5. Treatment of Port-Wine Stains with Flash Lamp Pumped Pulsed Dye Laser on Indian Skin: A Six Year Study

    PubMed Central

    Thajudheen, Chandroth Ponnambath; Jyothy, Kannangath; Priyadarshini, Arul

    2014-01-01

    Context: Port-wine stain (PWS) is one of the commonly encountered congenital cutaneous vascular lesions, with an equal sex distribution. Pulsed dye lasers (PDL) have revolutionized the treatment of both congential and acquired cutaneous vascular lesions. The pulsed dye lasers owing to its superior efficacy and safety profile have become the gold standard for the management of port-wine stains. Aims: To evaluate the efficacy and side effects of pulsed dye laser for the management of Port-wine stain on Indian skin. Materials and Methods: Seventy five patients of Fitzpatrick skin types IV&V with PWS underwent multiple treatments with PDL (V beam-Candela) over a period of six years at monthly intervals. Laser parameters were wavelength 595nm, spot sizes 7-10mm, fluence 6-12 j/cm2, pulse duration 0.45-10ms, along with cryogen cooling. Serial photographs were taken before and after every session. Clinical improvement scores of comparable photographs using a quartile grading (o=<20%, 1=21-40%, 2=41-60%, 3=61-80%, 4=>80%) were judged independently by two dermatologists after the series of treatment. Minimum number of treatments was 6 and maximum 17. They were followed up at six monthly intervals to observe re darkening of PWS. Results: No patient showed total clearance.Grade3 improvement was observed in 70 % of children and 50% of adults after 8-10 sessions. Children showed better and faster response than adults. Thirty percent of patients developed post inflammatory hyper pigmentation which resolved over a period of six to eight weeks. Two patients had superficial scarring due to stacking of pulses. None of the patients showed re darkening of PWS till now. Conclusion: Pulsed dye laser is an effective and safe treatment for port-wine stain in Indian skin. PMID:24761097

  6. In vivo experiment study of nonablative photorejuvenation by using a 595-nm pulsed dye laser

    NASA Astrophysics Data System (ADS)

    Dang, Yongyan; Ren, Qiushi; Li, Wangrong; Liu, Huaxu; Liu, Yuxiu; Zhang, Jinsheng

    2005-01-01

    The pulsed dye laser (PDL) has a history of producing safe and effective clearance of dermal vascular lesions; however, non-ablative treatments of rhytids with 595nm PDL are seldom studied. The purpose of our research is to evaluate the changes of skin elasticity, histology and the amount of hydroxyproline after 595nm PDL non-ablative rejuvenation and to offer references for effective clinical treatments. Forty KM mice were used for this experiment. Laser parameters were as follows: an energy fluence of 8 to 12J/cm2, a pulse duration of 10ms, and a spot size of 7mm with 10% overlap. Skin elasticity was measured using Reviscometer RVM 600. Specimens were sectioned for hematoxylin-eosin and Van-Gieson staining, and dermal thickness was recorded in an ocular micrometer. The amount of hydroxyproline in the dermis was quantified by the biochemical method. No marked side effects such as blister and purpura were noted during laser treatments. New collagen synthesized with an improvement in the organization of collagen fibrils. The 12 J/cm2 group improved skin elasticity by 31.7%, dermal thickness by 25.3% and the amount of hydroxyproline by 55.9%. There were the good correlations between dermal thickness and the amount of hydroxyproline. Therefore 595nm PDL non-ablative photo-rejuvenation is a safe and effective method for wrinkle reduction. And the energy level of 12 J/cm2 has the greatest effect in improving skin mechanical properties and accelerating new collagen formation.

  7. Re-evaluation of all-plastic organic dye laser with DFB structure fabricated using photoresists

    PubMed Central

    Tsutsumi, Naoto; Nagi, Saori; Kinashi, Kenji; Sakai, Wataru

    2016-01-01

    Organic solid-state lasers (OSSLs) with distributed feedback structures can detect nanoscale materials and therefore offer an attractive sensing platform for biological and medical applications. Here we investigate the lasing characteristics, i.e., the threshold and slope efficiency, as a function of the grating depth in OSSL devices with distributed feedback (DFB) structure fabricated using photoresists. Two types of photoresists were used for the DFB structures: a negative photoresist, SU-8 2002, and a positive photoresist, ma-P 1275. The DFB structure was fabricated using a Lloyd-mirror configuration. The active layer was a rhodamine 6G-doped cellulose acetate waveguide. The threshold for the first order mode (m  = 1) was lower than that for the second and third order modes (m = 2, and 3). A low threshold of 27 μJ cm−2 pulse−1 (58 nJ) was obtained using SU-8 2002, with m = 1. The slope efficiency was evaluated as a function of grating depth for each mode and increased as the grating depth increased. PMID:27703217

  8. Re-evaluation of all-plastic organic dye laser with DFB structure fabricated using photoresists

    NASA Astrophysics Data System (ADS)

    Tsutsumi, Naoto; Nagi, Saori; Kinashi, Kenji; Sakai, Wataru

    2016-10-01

    Organic solid-state lasers (OSSLs) with distributed feedback structures can detect nanoscale materials and therefore offer an attractive sensing platform for biological and medical applications. Here we investigate the lasing characteristics, i.e., the threshold and slope efficiency, as a function of the grating depth in OSSL devices with distributed feedback (DFB) structure fabricated using photoresists. Two types of photoresists were used for the DFB structures: a negative photoresist, SU-8 2002, and a positive photoresist, ma-P 1275. The DFB structure was fabricated using a Lloyd-mirror configuration. The active layer was a rhodamine 6G-doped cellulose acetate waveguide. The threshold for the first order mode (m  = 1) was lower than that for the second and third order modes (m = 2, and 3). A low threshold of 27 μJ cm‑2 pulse‑1 (58 nJ) was obtained using SU-8 2002, with m = 1. The slope efficiency was evaluated as a function of grating depth for each mode and increased as the grating depth increased.

  9. Effect of solvent viscosity on the anisotropy of distribution of excited centers in an active medium of a dye laser at a pump power near the threshold value

    SciTech Connect

    Yartsev, A.I.; Sechkarev, A.V.

    1995-03-01

    Dependences of the anisotropy of the distribution of excited centers (A) in rhodamine 6G and 6-aminophenolenon solutions in organic solvents of different viscosity are studied. Relying on the character of the dependence of A on the viscosity, the conclusion is made that it is possible to employ a relation similar to the Levshin-Perrin formula for polarized luminescence in the threshold excitation mode. Experimental data are used to calculate angles between absorption and emission dipoles of electron auxochrome groups of molecules for the dyes under investigation and to estimate the effective volume of activator molecules for the ethanol solution of rhodamine 6G. 6 refs., 1 fig.

  10. Stability and astigmatic compensation analysis of five- and six- or seven-mirror cavities for mode-locked dye lasers

    SciTech Connect

    Cojocaru, E.; Julea, T.; Herisanu, N.

    1989-07-01

    An analysis of the stability and astigmatic compensation of five- and six- or seven-mirror cavities for mode-locked dye lasers and simple relations for the folding angle to get a maximum stability region are given in this paper. Analytical relations referring to equivalent resonators are deduced. We draw attention to the lack of opportunity to use long cavity approximation to obtain stability diagrams and made some considerations on beam waist sizes.

  11. Efficient photocatalytic degradation of rhodamine 6G with a quantum dot-metal organic framework nanocomposite.

    PubMed

    Kaur, Rajnish; Vellingiri, Kowsalya; Kim, Ki-Hyun; Paul, A K; Deep, Akash

    2016-07-01

    The hybrid structures of metal organic frameworks (MOFs) and nanoparticles may offer the realization of effective photocatalytic materials due to combined benefits of the porous and molecular sieving properties of MOF matrix and the functional characteristics of encapsulated nanoparticles. In this study, cadmium telluride (CdTe) quantum dots (QD) are conjugated with a europium-MOF for the synthesis of a novel nanocomposite material with photocatalytic properties. Successful synthesis of a QD/Eu-MOF nanocomposite was characterized with various spectroscopic and microscopic techniques. This QD/Eu-MOF is found to be an effective catalyst to complete the degradation of Rhodamine 6G dye within 50 min. PMID:27101017

  12. Study of nonlinear refraction of organic dye by Z-scan technique using He-Ne laser

    SciTech Connect

    Medhekar, S.; Kumar, R.; Mukherjee, S.; Choubey, R. K.

    2013-02-05

    Laser induced third-order nonlinear optical responses of Brilliant Green solution has been investigated by utilizing single beam Z-scan technique with a continuous-wave He-Ne laser radiation at 632.8 nm. It was observed that the material exhibits self-defocusing type optical nonlinearity. The measurements of nonlinear refraction were carried out at different dye concentrations and found that the increase in solution concentration leads to the linear increase of the nonlinear refractive index. The experimental results confirm great potential of the Brilliant Green for the application in nonlinear optical devices.

  13. Hyper-Rayleigh scattering and hyper-Raman scattering of dye-adsorbed silver nanoparticles induced by a focused continuous-wave near-infrared laser

    SciTech Connect

    Itoh, Tamitake; Ozaki, Yukihiro; Yoshikawa, Hiroyuki; Ihama, Takashi; Masuhara, Hiroshi

    2006-02-20

    We report that hyper-Rayleigh scattering, surface-enhanced hyper-Raman scattering, and two-photon excited luminescence occur intermittently by focusing a continuous-wave near-infrared (cw-NIR) laser into a colloidal silver solution including rhodamine 6G (R6G) and sodium chloride (NaCl). On the other hand, continuous hyper-Rayleigh scattering is observed from colloidal silver free from R6G and NaCl, demonstrating that hyper-Raman scattering and two-photon excited luminescence are attributed to R6G and their intermittent features are dependent on the colloidal dispersion. These results suggest that the cw-NIR laser has three roles; the source of the nonlinear response, optical trapping of nanoparticles, and making nanoparticle aggregates possessing the high activity for the nonlinear response.

  14. Mechanism for radiative energy transfer and expansion of the spectral lasing range in a rhodamine 6G--oxazine 17 system

    SciTech Connect

    Reva, M.G.; Akimov, A.I.; Korol'kova, N.V.; Kurokhtin, N.V.; Uzhinov, B.M.

    1985-12-01

    The nature of radiative transfer of electronic excitation energy from rhodamine 6G to oxazine 17 is determined. As a result of laser excitation, lasing in the acceptor (oxazine 17) is achieved due to absorption of donor (rhodamine 6G) luminescence by its molecules. The continuous tuning range of single-component ethanol solutions of rhodamine 6G and oxazine 17, and of a binary rhodamine 6G--oxazine 17 system with energy transfer, is determined.

  15. Experimental study of generalized self-filtering unstable resonators in an ablative-wall flash-lamp-pumped dye laser.

    PubMed

    Mahmodi, M; Farahbod, A H; Hariri, A

    1998-02-20

    The performance of a generalized self-filtering unstable resonator (GSFUR) that consists of two curved mirrors in a nonconfocal scheme with a low magnification of M = -1.62 in an ablative-wall flash-lamp dye laser is reported. The objective was to study the near- and far-field intensity distribution and the divergence of the laser beam. It was found that the output beam has a nearly Gaussian distribution with a pulse duration of ~400 ns FWHM, almost independent of the diameter of the field-limiting aperture, but increases slightly with the pumping rate. A diffraction-limited laser beam of 1.1 mrad was obtained from this laser cavity. The output energy was ~1 mJ when an intracavity glass plate was used as an output coupler. The required relations needed for the GSFUR design were also derived. PMID:18268685

  16. Treatment of Hemorrhagic Vocal Polyps by Pulsed Dye Laser-Assisted Laryngomicrosurgery

    PubMed Central

    Byeon, Hyung Kwon; Han, Ji Hyuk; Choi, Byeong Il; Hwang, Hye Jin; Kim, Ji-Hoon; Choi, Hong-Shik

    2015-01-01

    Objective. Conventional surgical techniques of laryngomicrosurgery (LMS) on hemorrhagic vocal polyps are often difficult due to obscuration of the surgical field by inadvertent bleeding from the lesion, and there are often significant amounts of mucosal epithelium loss. Here, we introduce our surgical technique using pulsed dye laser (PDL), which can effectively resect the polyp with vocal fold mucosa preservation. Methods. Patients who were diagnosed with hemorrhagic vocal polyp and who were surgically managed using PDL from March 2013 to October 2014 were retrospectively reviewed. Preoperative and postoperative clinical outcomes and surgical findings were evaluated. Results. A total of 39 patients were treated with PDL-assisted enucleation LMS. The average age was 43.7 years (range 20–73), and there were 20 males and 19 females (17 professional voice users). In all cases, the hemorrhagic polyp was successfully enucleated after application of PDL, thereby preserving the overlying epithelium. Postoperative voice outcomes were favorable with clear preservation of the vocal fold mucosal wave. Conclusion. PDL-assisted enucleation LMS for the treatment of hemorrhagic vocal polyps can be a safe and effective surgical technique. It can be considered a promising treatment option for hemorrhagic vocal polyps. PMID:26557700

  17. Optimal operating regime of saturable absorbers in mode-locked lasers

    SciTech Connect

    Narovlyanskaya, N.M.; Tikhonov, E.A.

    1982-01-01

    An investigation was made of ultrashort pulse generation by passive mode locking in a rhodamine 6G jet laser with pulsed laser pumping of up to 300 nsec duration. In order to obtain single ultrashort pulses per axial period in these systems, it was essential to reduce their time of formation to several loop passes. It was shown experimentally that the rate of formation of ultrashort pulses is influenced appreciably by the nonlinear absorber dye and, for a given intracavity intensity, the best dyes are those having a purely electronic transition near the lasing frequency. In this case, the critical bleaching intensity and relaxation time are minimized as a result of the increased role of stimulated resonance transitions in the dye modulator. Optimal types of polymethine dyes are suggested for nonlinear absorbers of tunable ultrashort-pulse rhodamine 6G lasers.

  18. Influence of lithium iodide on association of rhodamine 6G molecules in mixtures of isopropanol with CCl/sub 4/

    SciTech Connect

    Saletskii, A.M.; Shekunov, V.A.; Yuzhakov, V.I.

    1987-11-01

    The spectral-luminescent properties of rhodamine 6G on addition of lithium iodide to the solutions were studied in mixtures of polar (isopropanol) and nonpolar (carbon tetrachloride) solvents. It was found that when LiI is added, the complex associates of the dye molecules formed in solutions containing more than 90 vol. % of CCl/sub 4/ dissociate into rhodamine 6G monomers. The enthalpy of association of rhodamine depends on the concentration of the salt in the system. The volume and the geometry of the complexes have been evaluated from the data of the polarization characteristics of the fluorescence of the associates.

  19. Optimization of lasing in an inverted-opal titania photonic crystal cavity as an organic solid-state dye-doped laser.

    PubMed

    Zhang, Dingke; Chen, Shijian; Jiang, Maohua; Ye, Lijuan

    2014-11-10

    Lasing performance of a dye-doped laser by encapsulating orange fluorescent dye 4-(Dicyanomethylene)-2-methyl-6-(4-dimethylaminostyryl)-4H-pyran (DCM) with different concentrations in a highly ordered three-dimensional (3D) inverted-opal titania (TiO2) photonic crystal (PC) microcavity was studied. The lasing threshold and laser quality were improved by optimizing the concentration of the laser dye DCM. When the concentration of DCM is optimized to 10-4  mol/l, the photoluminescence (PL) efficiency of DCM is sufficient to achieve lasing emission and meanwhile no fluorescence quantum quenching occurs. Therefore, the emission spectrum was greatly narrowed and the threshold was significantly improved, which reached 0.8  mJ pulse-1 cm-2. Our findings are promising results toward the realization of fabricating a highly efficient low-threshold organic laser.

  20. Optimization of lasing in an inverted-opal titania photonic crystal cavity as an organic solid-state dye-doped laser.

    PubMed

    Zhang, Dingke; Chen, Shijian; Jiang, Maohua; Ye, Lijuan

    2014-11-10

    Lasing performance of a dye-doped laser by encapsulating orange fluorescent dye 4-(Dicyanomethylene)-2-methyl-6-(4-dimethylaminostyryl)-4H-pyran (DCM) with different concentrations in a highly ordered three-dimensional (3D) inverted-opal titania (TiO2) photonic crystal (PC) microcavity was studied. The lasing threshold and laser quality were improved by optimizing the concentration of the laser dye DCM. When the concentration of DCM is optimized to 10-4  mol/l, the photoluminescence (PL) efficiency of DCM is sufficient to achieve lasing emission and meanwhile no fluorescence quantum quenching occurs. Therefore, the emission spectrum was greatly narrowed and the threshold was significantly improved, which reached 0.8  mJ pulse-1 cm-2. Our findings are promising results toward the realization of fabricating a highly efficient low-threshold organic laser. PMID:25402981

  1. Laser-induced bioluminescence

    SciTech Connect

    Hickman, G.D.; Lynch, R.V. III

    1981-01-01

    A project has been initiated to determine the feasibility of developing a complete airborne remote sensing system for rapidly mapping high concentration patches of bioluminescent organisms in the world's oceans. Conceptually, this system would be composed of a laser illuminator to induce bioluminescence and a low light level image intensifier for detection of light. Initial laboratory measurements consisted of using a 2-J flash lamp pulsed optical dye laser to excite bioluminescence in the marine dinoflagellate Pyrocustis lunula at ambient temperature using Rhodamine 6G as the lasing dye (585 nm) and a laser pulse width of 1 microsec. After a latency period of 15-20 msec, the bioluminescence maximum occurred in the blue (480 nm is the wavelength maximum for most dinoflagellate bioluminescence) with the peaking occurring approximately 65 msec after the laser pulse. Planned experiments will investigate the effect of different excitation wavelengths and energies at various temperatures and salinities of the cultures.

  2. Treatment of basal-cellular skin cancer and heavy concomitant diseases by a photodynamic therapeutic method with a dye laser LITT-PDT

    NASA Astrophysics Data System (ADS)

    Evtushenko, V. A.; Soldatov, A. N.; Vusik, M. V.; Reimer, I. V.

    2008-01-01

    Experimental results of initial testing dye-laser "LITT-PDT" pumped by a copper vapor laser are presented. "LITT PDT" is a modern laser medical complex on CVL-pumped dye laser, generating radiation in a red spectrum area with a tuning wavelength of 630 - 700 nm and preserving high intensity of radiation on each wavelength, necessary for treatment by a photodynamic therapeutic method (PDM). Radiation in a red spectrum area (630 - 700 nm) enables treatment for oncological diseases by PDM using any photosensitizer. The given laser medical complex, generating radiation simultaneously on yellow and green discrete spectrum lines, makes methods of low intensive laser therapy for treatment of precancer and dermatological diseases possible.

  3. Synthesis and characterization of gold graphene composite with dyes as model substrates for decolorization: a surfactant free laser ablation approach.

    PubMed

    Sai Siddhardha, R S; Lakshman Kumar, V; Kaniyoor, Adarsh; Sai Muthukumar, V; Ramaprabhu, S; Podila, Ramakrishna; Rao, A M; Ramamurthy, Sai Sathish

    2014-12-10

    A facile surfactant free laser ablation mediated synthesis (LAMS) of gold-graphene composite is reported here. The material was characterized using transmission electron microscopy, field emission scanning electron microscopy, energy dispersive X-ray spectroscopy, powdered X-ray diffraction, Raman spectroscopy, Zeta potential measurements and UV-Visible spectroscopic techniques. The as-synthesized gold-graphene composite was effectively utilized as catalyst for decolorization of 4 important textile and laser dyes. The integration of gold nanoparticles (AuNPs) with high surface area graphene has enhanced the catalytic activity of AuNPs. This enhanced activity is attributed to the synergistic interplay of pristine gold's electronic relay and π-π stacking of graphene with the dyes. This is evident when the Rhodamine B (RB) reduction rate of the composite is nearly twice faster than that of commercial citrate capped AuNPs of similar size. In case of Methylene blue (MB) the rate of reduction is 17,000 times faster than uncatalyzed reaction. This synthetic method opens door to laser ablation based fabrication of metal catalysts on graphene for improved performance without the aid of linkers and surfactants.

  4. Low-pulse energy Q-switched Nd:YAG laser treatment for hair-dye-induced Riehl's melanosis.

    PubMed

    On, Hye Rang; Hong, Won Jin; Roh, Mi Ryung

    2015-06-01

    Riehl's melanosis, a form of dermatitis characterized by reticulate pigmentation, typically presents as a gray-brown to black hyperpigmentation on the face and neck. Among the various etiologic factors suggested, photoallergic reaction and pigmented contact dermatitis resulting from exposure to drugs, coal tar dyes, optical whitener, or other ingredients found in cosmetics are believed to be the major contributing factors in this disease. The histopathological features of Riehl's melanosis mainly consist of pigmentary incontinence along with infiltration of numerous dermal melanophages and lymphohistiocytes.1,2 Additionally, notable clinical improvements in the treatment of this condition have been reported for intense pulsed light (IPL) therapy, in comparison to long-term topical application of bleaching agents.2 Here, we report the cases of two Asian patients treated with a low-pulse energy 1,064-nm Q-switched (QS) Nd:YAG laser for hair dye-induced Riehl's melanosis on the face and neck. In conclusion, we observed that Riehl's melanosis on the face and neck was effectively and safely treated with a low-pulse energy 1,064-nm QS Nd:YAG laser. We suggest that this method can be used in Asian patients with Riehl's melanosis at risk of postinflammatory hyperpigmentation from excessive light or laser energy delivery. PMID:25602355

  5. Synthesis and characterization of gold graphene composite with dyes as model substrates for decolorization: A surfactant free laser ablation approach

    NASA Astrophysics Data System (ADS)

    Sai Siddhardha, R. S.; Lakshman Kumar, V.; Kaniyoor, Adarsh; Sai Muthukumar, V.; Ramaprabhu, S.; Podila, Ramakrishna; Rao, A. M.; Ramamurthy, Sai Sathish

    2014-12-01

    A facile surfactant free laser ablation mediated synthesis (LAMS) of gold-graphene composite is reported here. The material was characterized using transmission electron microscopy, field emission scanning electron microscopy, energy dispersive X-ray spectroscopy, powdered X-ray diffraction, Raman spectroscopy, Zeta potential measurements and UV-Visible spectroscopic techniques. The as-synthesized gold-graphene composite was effectively utilized as catalyst for decolorization of 4 important textile and laser dyes. The integration of gold nanoparticles (AuNPs) with high surface area graphene has enhanced the catalytic activity of AuNPs. This enhanced activity is attributed to the synergistic interplay of pristine gold's electronic relay and π-π stacking of graphene with the dyes. This is evident when the Rhodamine B (RB) reduction rate of the composite is nearly twice faster than that of commercial citrate capped AuNPs of similar size. In case of Methylene blue (MB) the rate of reduction is 17,000 times faster than uncatalyzed reaction. This synthetic method opens door to laser ablation based fabrication of metal catalysts on graphene for improved performance without the aid of linkers and surfactants.

  6. Laser performance of Coumarin 540A dye molecules in polymeric host media with different viscosities: From liquid solution to solid polymer matrix

    SciTech Connect

    Costela, A.; Garcia-Moreno, I.; Barroso, J.; Sastre, R.

    1998-01-01

    Photophysical parameters and lasing properties of Coumarin 540A dye molecules are studied in solutions of increasing viscosity, from liquid solutions in 1,4-dioxane to solid solutions in poly(methyl methacrylate). The fluorescence quantum yield and lasing efficiencies decrease as the viscosity of the solution increases, reflecting the strong influence of the rigidity of the medium on the radiative processes. The photodegradation mechanisms acting on the fluorophores are analyzed by following the dependence of laser induced fluorescence and laser output on the number of pump laser pulses. The fluorescence redistribution after pattern photobleaching technique is used, and Fick{close_quote}s second law is applied to study the diffusion of dye molecules in the highly viscous polymer solutions. The diffusion coefficients of the dye molecules as a function of the increased viscosity of the medium are determined. {copyright} {ital 1998 American Institute of Physics.}

  7. Development of injection-seeded optical parametric laser systems with pulsed dye amplifiers for high-spectral-resolution combustion diagnostics

    NASA Astrophysics Data System (ADS)

    Bhuiyan, Aizaz Hossain

    The development and application of optical parametric (OP) systems with pulsed dye amplifiers producing single frequency mode (SFM), narrow linewidth, and tunable laser radiation for high-spectral-resolution laser diagnostics is described. An optical parametric generator (OPG) was developed, consisting of a pair of counter-rotating β barium borate (β-BBO) crystals pumped by third-harmonic output of an injection-seeded Nd:YAG laser. The OPG crystals themselves are injection-seeded using a continuous wave (cw) distributed feedback (DFB) diode laser or external cavity diode laser (ECDL) at idler wavelength. The OPG is converted for some applications into an optical parametric oscillator (OPO) by incorporating a feedback cavity. The signal output from the OP system is amplified using pulsed dye amplifiers. The PDAs are pumped either by second-harmonic or third-harmonic output of the Nd:YAG laser depending on the OP output wavelength and the dye solution used in PDAs. The linewidth of the laser beam produced using OP/PDA systems is 200 MHz and the spatial beam profile is nearly Gaussian. Initial application of OP/PDA system included two-photon laser induced fluorescence (LIF) of atomic oxygen in counter-flow flames, dual pump coherent anti-Stokes Raman spectroscopy (CARS) for N2 and CO2, and nitric oxide (NO) planar laser induced fluorescence (PLIF) in compressible flowfield. A two-photon pump polarization spectroscopy probe (TPP-PSP) laser system has also been developed using two SFM OPG/PDA systems for the detection of atomic hydrogen (H-atom) in flames. In TPP-PSP, a 243-nm pump beam excites the 1S-2S two photon transition and the excited atoms in 2S level are probed by polarization spectroscopy between n=2 and n=3 manifolds using a circularly polarized 656-nm pump and a linearly polarized 656-nm probe laser beam. Using the TPP-PSP scheme, atomic hydrogen was detected at concentrations as low as 11 ppm. The use of injection-seeded OPG/PDAs as SFM sources for the

  8. Microarray Analysis of Port Wine Stains Before and After Pulsed Dye Laser Treatment

    PubMed Central

    Laquer, Vivian T.; Hevezi, Peter A.; Albrecht, Huguette; Chen, Tina S.; Zlotnik, Albert; Kelly, Kristen M.

    2014-01-01

    Background and Objectives Neither the pathogenesis of port wine stain (PWS) birthmarks nor tissue effects of pulsed dye laser (PDL) treatment of these lesions is fully understood. There are few published reports utilizing gene expression analysis in human PWS skin. We aim to compare gene expression in PWS before and after PDL, using DNA microarrays that represent most, if not all, human genes to obtain comprehensive molecular profiles of PWS lesions and PDL-associated tissue effects. Materials and Methods Five human subjects had PDL treatment of their PWS. One week later, three biopsies were taken from each subject: normal skin (N); untreated PWS (PWS); PWS post-PDL (PWS + PDL). Samples included two lower extremity lesions, two facial lesions, and one facial nodule. High-quality total RNA isolated from skin biopsies was processed and applied to Affymetrix Human gene 1.0ST microarrays for gene expression analysis. We performed a 16 pair-wise comparison identifying either up- or down-regulated genes between N versus PWS and PWS versus PWS + PDL for four of the donor samples. The PWS nodule (nPWS) was analyzed separately. Results There was significant variation in gene expression profiles between individuals. By doing pair-wise comparisons between samples taken from the same donor, we were able to identify genes that may participate in the formation of PWS lesions and PDL tissue effects. Genes associated with immune, epidermal, and lipid metabolism were up-regulated in PWS skin. The nPWS exhibited more profound differences in gene expression than the rest of the samples, with significant differential expression of genes associated with angiogenesis, tumorigenesis, and inflammation. Conclusion In summary, gene expression profiles from N, PWS, and PWS + PDL demonstrated significant variation within samples from the same donor and between donors. By doing pair-wise comparisons between samples taken from the same donor and comparing these results between donors, we were

  9. Small-beam, low-power argon-pumped tunable dye laser at 585 nm for the treatment of cherry angiomas

    NASA Astrophysics Data System (ADS)

    Littler, Curt M.

    1990-06-01

    An argon-pumped tunable dye laser tuned to 585 nm was used to treat clinically typical cherry angiomas in a preliminary study. A spot size of 0.1 mm and low power (0.1 - 0.15W) in the continuous mode was used for treatment. Results ranged from decrease in size of the cherry angioma to complete regression. In all cases, there was minimal to no scarring. Further study in the treatment of elevated cutaneous vascular lesions with the continuous wave dye laser seems warranted.

  10. Biostimulative effects of Nd:YAG Q-switch dye on normal human fibroblast cultures: study of a new chemosensitizing agent for the Nd:YAG laser

    SciTech Connect

    Castro, D.J.; Saxton, R.E.; Fetterman, H.R.; Castro, D.J.; Ward, P.H.

    1987-12-01

    Kodak Q-switch II is a new chemical with an absorption maxima at 1051 nm, designed to be used as an Nd:YAG dye laser. The potential for this dye as a new chemosensitizing agent in the treatment of connective tissue diseases and wound healing with low energy Nd:YAG laser was examined. Two normal fibroblast cell lines were tested for sensitivity to various levels of this dye in vitro. These cells were exposed to Q-switch II dye at concentrations of 0.01, 0.1, 1, 10, 50, and 100 micrograms/ml for 1 and 24 hours. Cell viability was assessed by the trypan blue exclusion test. Cell duplication and DNA synthesis were measured by the incorporation of (/sup 3/H)-thymidine at 6 and 24 hours postexposure to Q-switch II dye. At concentrations up to 10 micrograms/ml, both cell lines tested showed no changes in cell viability. However, at concentrations equal or higher than 50 micrograms/ml, more than 40% of the fibroblasts incorporated trypan blue after 24 hours of exposure to this dye, indicating significant cell destruction. The results indicate that Q-switch II dye is nontoxic to normal human fibroblast cultures and showed significant biostimulative effects on cell duplication at concentrations equal to or lower than 10 micrograms/ml. Further studies will be required to determine the usefulness of Q-switch II dye as a new photochemosensitizing agent for potential biostimulation of wound healing and/or treatment of connective tissue diseases with the Nd:YAG laser (near infrared, 1060 nm) at nonthermal levels of energies.

  11. Time-resolved laser-induced fluorescence study on dyes used in DNA sequencing

    SciTech Connect

    Chang, Kaisyang; Force, R.K. )

    1993-01-01

    Research on the time-resolved fluorescence of fluorescein isothiocyanate, NBD, tetramethylrhodamine isothiocyanate, and Texas Red - the dyes used for fluorescence-based DNA sequencing - is described. Mean fluorescence lifetiems in both aqueous buffer solution and 5.3%T, 4.8%C polyacrylamide gel were determined as a function of excitation wave-lengths at 337, 470, and 550 nm and were found to be 3.5, 1.1, 2.5, and 4.3 ns; the detection limits are 10, 200, 200 and 200 amol for FITC, NBD, TEMR, and T. Red, respectively. Comparisons of fluorescence parameters between the conjugated dyes and the free dyes are also reported. Results on the optimization of the excitation source wavelengths to improve sensitivity and reduce background scattering in polyacrylamide gel are also reported. Time-resolved fluorescence was successfully applied to resolve spectral overlapping of emissions in both solution and in polyacrylamide gel. 12 refs., 6 figs., 1 tab.

  12. Phenothiazinium dyes in association with diode red laser against B16F10 melanoma cells: in vitro study

    NASA Astrophysics Data System (ADS)

    Miranda, Anderson F.; Santos, Gustavo M. P.; de Oliveira, Susana C. P. S.; Monteiro, Juliana S. C.; Sampaio, Fernando J. P.; Gomes Júnior, Rafael Araújo; Brugnera, Aldo; Gesteira, Maria F. M.; Zanin, Fátima A. A.; Pinheiro, Antônio Luiz B.; Vannier-Santos, Marcos A.

    2014-02-01

    In Brazil solar incidence is high and continuous throughout the year. Body exposure to sunlight may be a key point in the rates of individuals affected by melanoma and other types of skin cancer in many countries. Brazil already occupies the 15th place in the ranking of melanoma cases and the limitations presented by drugs used in the therapy of this cancer, new approaches are being used in an attempt to decrease the mortality of this malignancy. The aim of this study was to evaluate the effects of phenothiazinium dyes (PD) associated with laser light on murine melanoma (B16F10) in vitro by measuring cell growth using colorimetric assay before and after photodynamic therapy. We used a diode laser (λ660nm, 2.4 J/cm2, 40 mW, 60 s, CW) associated with PD at 12.5 μg/mL, time pre-irradiation of 30 minutes). The following groups were tested: control (LF-), PD (L-F+), Laser (L+F-), Laser + PD (L+F+). The results showed a significant reduction in cell growth in the group treated by the photodynamic therapy compared to the control at 24 and 48 h (p < 0.001). Were showing at 30 min PD has a dose-dependent response on B16F10 cells, but at 24 h did not demonstrated this response.

  13. Platinum-scatterer-based random lasers from dye-doped polymer-dispersed liquid crystals in capillary tubes.

    PubMed

    Wang, Jianlong; Zhang, Yating; Cao, Mingxuan; Song, Xiaoxian; Che, Yongli; Zhang, Haiting; Zhang, Heng; Yao, Jianquan

    2016-07-20

    The resonance characteristics of platinum-scatter-based random lasers from dye-doped polymer-dispersed liquid crystals (DDPDLCs) in capillary tubes were researched for the first time, to the best of our knowledge. After adding platinum nanoparticles (Pt NPs) into the liquid crystal mixtures, the emission spectra of DDPDLCs revealed a lower lasing threshold in comparison with those of DDPDLCs without Pt NPs due to light scattering of liquid crystal droplets and the local field enhancement around Pt NPs. Furthermore, the full width at half-maximum (FWHM) and the lasing threshold were determined by the doping density of the Pt NPs. The threshold was decreased by about half from 17.5  μJ/pulse to 8.7  μJ/pulse on the condition that around 1.0 wt. % was the optimum concentration of Pt NPs doped into the DDPDLCs. The FWHM of the peaks sharply decreased to 0.1 nm. Our work provides an extremely simple method to enhance random lasers from DDPDLCs doped with Pt NPs, and it has potential applications in random fiber lasers or laser displays.

  14. Platinum-scatterer-based random lasers from dye-doped polymer-dispersed liquid crystals in capillary tubes.

    PubMed

    Wang, Jianlong; Zhang, Yating; Cao, Mingxuan; Song, Xiaoxian; Che, Yongli; Zhang, Haiting; Zhang, Heng; Yao, Jianquan

    2016-07-20

    The resonance characteristics of platinum-scatter-based random lasers from dye-doped polymer-dispersed liquid crystals (DDPDLCs) in capillary tubes were researched for the first time, to the best of our knowledge. After adding platinum nanoparticles (Pt NPs) into the liquid crystal mixtures, the emission spectra of DDPDLCs revealed a lower lasing threshold in comparison with those of DDPDLCs without Pt NPs due to light scattering of liquid crystal droplets and the local field enhancement around Pt NPs. Furthermore, the full width at half-maximum (FWHM) and the lasing threshold were determined by the doping density of the Pt NPs. The threshold was decreased by about half from 17.5  μJ/pulse to 8.7  μJ/pulse on the condition that around 1.0 wt. % was the optimum concentration of Pt NPs doped into the DDPDLCs. The FWHM of the peaks sharply decreased to 0.1 nm. Our work provides an extremely simple method to enhance random lasers from DDPDLCs doped with Pt NPs, and it has potential applications in random fiber lasers or laser displays. PMID:27463926

  15. Spectral characteristics of DFB polymer lasers

    NASA Astrophysics Data System (ADS)

    Dumarcher, Vincent; Rocha, Licinio; Denis, Christine; Fiorini-Debuisschert, Celine; Nunzi, Jean-Michel; Sobel, Frank; Sahraoui, Bouchta; Gindre, Denis; Kretsch, Kevin P.; Blau, Werner J.; Pfeiffer, S.; Tillmann, Hartwig; Hoerhold, Hans-Heinrich; Maillou, Thierry; Le Moigne, Jacques

    2000-05-01

    We present a study of Distributed Feedback laser emission in various polymer materials. This laser scheme permits efficient control of the stimulated emission in dye doped polymer materials. Optical feedback is provided by distributed Bragg gratings formed in the film by interference patterns from the pump beam. We demonstrate broad tunability of laser emission in polymeric waveguides doped with stilbenoid, phenylene vinylene and oligomers of phenyl ethynylene used for OLEDs. Laser action was also obtained with Rhodamine 6G in PMMA deposited on surface relief grating and excited in a transverse single beam pumping geometry.

  16. Amplified spontaneous emission of Rhodamine 6G embedded in pure deoxyribonucleic acid

    NASA Astrophysics Data System (ADS)

    Rau, Ileana; Szukalski, Adam; Sznitko, Lech; Miniewicz, Andrzej; Bartkiewicz, Stanislaw; Kajzar, Francois; Sahraoui, Bouchta; Mysliwiec, Jaroslaw

    2012-10-01

    Deoxyribonucleic acid (DNA) is commonly viewed as a genetic information carrier. However, now it is recognized as a nanomaterial, rather than as a biological material, in the research field of nanotechnology. Here, we show that using pure DNA, doped with rhodamine 6G, we are able to observe amplified spontaneous emission (ASE) phenomenon. Moderate ASE threshold, photodegradation, and reasonable gain coefficient observed in this natural host gives some perspectives for practical applications of this system in biophotonics. Obtained results open the way and will be leading to construction of truly bio-lasers using nature made luminophores, such as anthocyanins.

  17. Ab initio theoretical reinvestigation of the ground and excited state properties of silylated coumarins: Good candidates for solid state dye lasers and dye-sensitized solar cells.

    PubMed

    Jain, Virendra Kumar

    2015-11-01

    We present ab initio theoretical calculations of various properties of the ground and excited states of basic coumarin (1) and its derivatives: 4-methylcoumarin (2), 7-aminocoumarin (3), 7-amino-4-methylcoumarin or coumarin 120 (4), 4-trifluoromethylcoumarin (5), 7-amino-4-trifluoromethylcoumarin or coumarin 151 (6), silylated coumarin 120 (7) and silylated coumarin 151 (8). We calculate the following: (i) ground and excited state dipole moments (ii) energies and locations of HOMOs and LUMOs (iii) SCF total energies of ground state (iv) excitation energies with oscillator strengths for first six excited states (v) C=O and C-N bond lengths in ground and excited states (vi) ground state thermodynamic and electronic properties. The ground and excited state properties of coumarins 1-8 are obtained within the framework of density functional theory using B3LYP and long-range-corrected (LRC) ωB97X-D functionals with 6-31G(d,p) basis set. A detailed comparative analysis of different photo physical and electronic properties of silylated and unsilylated coumarins is made. On the basis of theoretical results we find many interesting features of silylation process and we can conclude that silylation will result in better long-term photo and thermodynamic stability compared to its unsilylated counterpart due to increase in the values of thermodynamic parameters like SCF total energy, G(0) and H(0), etc. Therefore, silylated molecules may become good candidates for solid state dye lasers and dye sensitized solar cells. In contrast, we find that both the functional B3LYP and LRC-ωB97X-D predict nearly the same results for electronic, thermodynamic and photo physical properties of studied coumarins 1-8 in their ground states but B3LYP hybrid functional severely overestimates excited state dipole moments, underestimates vertical excitation energies, oscillator strengths, C=O and C-N bond lengths of studied coumarins. On the basis of our theoretical results we conclude that LRC

  18. Self-phase-modulation-controlled passively mode-locked dye laser

    SciTech Connect

    Wang, C.; Ishida, Y.; Yamamoto, Y. )

    1990-09-01

    We demonstrate a laser that permits self-phase modulation to be controlled independently of other parameters in a colliding-pulse mode-locked laser system. With this laser system, pulse compression by a factor of 1.5 was observed, and a stronger soliton effect was found.

  19. Sonocatalytic and sonophotocatalytic degradation of Rhodamine 6G containing wastewaters.

    PubMed

    Bokhale, Nileema B; Bomble, Snehal D; Dalbhanjan, Rachana R; Mahale, Deepika D; Hinge, Shruti P; Banerjee, Barnali S; Mohod, Ashish V; Gogate, Parag R

    2014-09-01

    The present work deals with degradation of aqueous solution of Rhodamine 6G (Rh 6G) using sonocatalytic and sonophotocatalytic treatment schemes based on the use of cupric oxide (CuO) and titanium dioxide (TiO2) as the solid catalysts. Experiments have been carried out at the operating capacity of 2 L and constant initial pH of 12.5. The effect of catalyst loading on the sonochemical degradation has been investigated by varying the loading over the range of 1.5-4.5 g/L. It has been observed that the maximum degradation of 52.2% was obtained at an optimum concentration of CuO as 1.5 g/L whereas for TiO2 maximum degradation was observed as 51.2% at a loading of 4 g/L over similar treatment period. Studies with presence of radical scavengers such as methanol (CH3OH) and n-butanol (C4H9OH) indicated lower extents of degradation confirming the dominance of radical mechanism. The combined approach of ultrasound, solid catalyst and scavengers has also been investigated at optimum loadings to simulate real conditions. The optimal solid loading was used for studies involving oxidation using UV irradiations where 26.4% and 28.9% of degradation was achieved at optimal loading of CuO and TiO2, respectively. Studies using combination of UV and US irradiations have also been carried out using the optimal concentration of the catalysts. It has been observed that maximum degradation of 63.3% is achieved using combined US and UV with TiO2 (4 g/L) as the photocatalyst. Overall it can be said that the combined processes give higher extent of degradation as compared to the individual processes based on US or UV irradiations.

  20. Combination of 595-nm pulsed dye laser, long-pulsed 755-nm alexandrite laser, and microdermabrasion treatment for keratosis pilaris: retrospective analysis of 26 Korean patients.

    PubMed

    Lee, Sang Ju; Choi, Min Ju; Zheng, Zhenlong; Chung, Won Soon; Kim, Young Koo; Cho, Sung Bin

    2013-06-01

    Keratosis pilaris (KP) has beenpresented as small keratotic follicular papules with or without surrounding erythema. Various treatments with laser or light therapy have been used for the management of KP with various clinical outcomes. In the present study, we investigated the efficacy and safety of a combination therapy for KP. A total of 29 anatomical sites with KP in 26 patients were treated using a 595-nm pulsed dye laser (PDL) with nonpurpuragenic fluences, a long-pulsed 755-nm alexandrite laser, and microdermabrasion. Clinical improvement was assessed by comparing preand posttreatment clinical photographs and patient satisfaction rates. Evaluation of the clinical results three months after the treatments showed that 12 of the 29 anatomical sites (41.4%) demonstrated Grade 3 clinical improvement, ten (34.5%) had Grade 2 clinical improvement, four (13.8%) showed Grade 1 improvement, and three (10.3%) showed Grade 4 improvement. We observed that KP lesions improved not only in erythema and skin texture, but also in brownish dyschromias. Potential adverse events were not observed, except prolonged posttherapy scaling. Our observations demonstrate that combination therapy using a 595-nm PDL, a long-pulsed 755-nm alexandrite laser, and microdermabrasion can have a positive therapeutic effect on KP.

  1. Combination of 595-nm pulsed dye laser, long-pulsed 755-nm alexandrite laser, and microdermabrasion treatment for keratosis pilaris: retrospective analysis of 26 Korean patients.

    PubMed

    Lee, Sang Ju; Choi, Min Ju; Zheng, Zhenlong; Chung, Won Soon; Kim, Young Koo; Cho, Sung Bin

    2013-06-01

    Keratosis pilaris (KP) has beenpresented as small keratotic follicular papules with or without surrounding erythema. Various treatments with laser or light therapy have been used for the management of KP with various clinical outcomes. In the present study, we investigated the efficacy and safety of a combination therapy for KP. A total of 29 anatomical sites with KP in 26 patients were treated using a 595-nm pulsed dye laser (PDL) with nonpurpuragenic fluences, a long-pulsed 755-nm alexandrite laser, and microdermabrasion. Clinical improvement was assessed by comparing preand posttreatment clinical photographs and patient satisfaction rates. Evaluation of the clinical results three months after the treatments showed that 12 of the 29 anatomical sites (41.4%) demonstrated Grade 3 clinical improvement, ten (34.5%) had Grade 2 clinical improvement, four (13.8%) showed Grade 1 improvement, and three (10.3%) showed Grade 4 improvement. We observed that KP lesions improved not only in erythema and skin texture, but also in brownish dyschromias. Potential adverse events were not observed, except prolonged posttherapy scaling. Our observations demonstrate that combination therapy using a 595-nm PDL, a long-pulsed 755-nm alexandrite laser, and microdermabrasion can have a positive therapeutic effect on KP. PMID:23464682

  2. Diode laser anastemoses of medium-size arteries with indocyanine green dye-enhanced albumine

    NASA Astrophysics Data System (ADS)

    Weng, Guo-Xing; Williamson, Warren; Aretz, H. Thomas

    1998-11-01

    In order to achieve a better long-term patency result and solve the problem of tensile strength in laser artery anastomoses, diode laser and Indocyanine Green (ICG) enhanced albumin were applied to medium-size artery anastomoses with three different methods, that is, direct laser vascular anastomoses, direct method enforced with ICG albumin, and laser welding with ICG albumin as 'solder'. Internal mammary artery (IMA) harvested from patients undergoing coronary bypass procedures, in vivo rat abdominal artery, and in vitro swine heart and IMA were chosen as the experimental materials. The results revealed that only 3.15 +/- 0.36 minutes were required for each anastomosis; the bursting pressure and tensile strength were greater in the groups enforced with ICG albumin and laser welding than that with direct laser anastomoses. In the laser soldering group, the thermal damage was limited in the adventitial layer, only at a depth of 200 micrometers . There was also a satisfied result in the in vivo laser welding rat's abdominal adventitial layer, only at a depth of 200 micrometers . There was also a satisfied result in the in vivo laser welding rat's abdominal arteries. However, end-to-side laser welding of IMA soronary artery with ICG albumin needs further investigation about its tensile strength in an in vivo model.

  3. Laser-pointer-induced self-focusing effect in hybrid-aligned dye-doped liquid crystals

    PubMed Central

    Wang, Jing; Aihara, Yosuke; Kinoshita, Motoi; Mamiya, Jun-ichi; Priimagi, Arri; Shishido, Atsushi

    2015-01-01

    Nonlinear optics deals with phenomena where “light controls light”; e.g., there is mediation by an intensity-dependent medium through which light propagates. This field has attracted much attention for its immense potential in applications dependent on nonlinear processes, such as frequency conversion, multiple-photon absorption, self-phase modulation, and so on. However, such nonlinearities are typically only observed at very high light intensities and thus they require costly lasers. Here, we report on a self-focusing effect induced with a 1 mW handheld laser pointer. We prepared polymer-stabilized dye-doped liquid crystals, in which the molecular director orientation gradually changes from homeotropic at one surface to homogeneous at the other. This is referred to as hybrid alignment. In such films, the threshold intensity needed to form diffraction rings was reduced by a factor of 8.5 compared to that in conventional homeotropic cells, which enabled the induction of the self-focusing effect with a laser pointer. PMID:25944052

  4. Laser-pointer-induced self-focusing effect in hybrid-aligned dye-doped liquid crystals

    NASA Astrophysics Data System (ADS)

    Wang, Jing; Aihara, Yosuke; Kinoshita, Motoi; Mamiya, Jun-Ichi; Priimagi, Arri; Shishido, Atsushi

    2015-05-01

    Nonlinear optics deals with phenomena where “light controls light” e.g., there is mediation by an intensity-dependent medium through which light propagates. This field has attracted much attention for its immense potential in applications dependent on nonlinear processes, such as frequency conversion, multiple-photon absorption, self-phase modulation, and so on. However, such nonlinearities are typically only observed at very high light intensities and thus they require costly lasers. Here, we report on a self-focusing effect induced with a 1 mW handheld laser pointer. We prepared polymer-stabilized dye-doped liquid crystals, in which the molecular director orientation gradually changes from homeotropic at one surface to homogeneous at the other. This is referred to as hybrid alignment. In such films, the threshold intensity needed to form diffraction rings was reduced by a factor of 8.5 compared to that in conventional homeotropic cells, which enabled the induction of the self-focusing effect with a laser pointer.

  5. Laser-pointer-induced self-focusing effect in hybrid-aligned dye-doped liquid crystals.

    PubMed

    Wang, Jing; Aihara, Yosuke; Kinoshita, Motoi; Mamiya, Jun-Ichi; Priimagi, Arri; Shishido, Atsushi

    2015-01-01

    Nonlinear optics deals with phenomena where "light controls light"; e.g., there is mediation by an intensity-dependent medium through which light propagates. This field has attracted much attention for its immense potential in applications dependent on nonlinear processes, such as frequency conversion, multiple-photon absorption, self-phase modulation, and so on. However, such nonlinearities are typically only observed at very high light intensities and thus they require costly lasers. Here, we report on a self-focusing effect induced with a 1 mW handheld laser pointer. We prepared polymer-stabilized dye-doped liquid crystals, in which the molecular director orientation gradually changes from homeotropic at one surface to homogeneous at the other. This is referred to as hybrid alignment. In such films, the threshold intensity needed to form diffraction rings was reduced by a factor of 8.5 compared to that in conventional homeotropic cells, which enabled the induction of the self-focusing effect with a laser pointer. PMID:25944052

  6. Thermal damage of tissue during near-infrared laser irradiation with assistance of light-absorbing dye

    NASA Astrophysics Data System (ADS)

    Gnyawali, Surya C.; Le, Kelvin; Le, Henry; Wicksted, James P.; Bartels, Kenneth E.; Liu, Hong; Chen, Yichao; Chen, Wei R.

    2008-02-01

    The selective photothermal-tissue interaction using dye enhancement has been proven to be effective in minimizing the peripheral normal tissue damage during cancer treatment. It is important that the tissue-thermal damage be analyzed and the damage rate process be estimated before the photothermal-immunotherapy for cancer treatment. In this study, we have used the EMT6 mouse tumor model for the laser-tumor treatment with a simultaneous surface temperature measurement using infrared thermography. The images acquired were processed to obtain the temperature profiles. The saturation temperature and corresponding time of irradiation from the temporal profiles were used to calculate the damage parameter using Arrhenius rate process equation. The damage parameters obtained from six mice were compared. Our results of in vivo study show that the damage analyses agree with the previous in vitro study on skins.

  7. Excitation laser energy dependence of surface-enhanced fluorescence showing plasmon-induced ultrafast electronic dynamics in dye molecules

    NASA Astrophysics Data System (ADS)

    Itoh, Tamitake; Yamamoto, Yuko S.; Tamaru, Hiroharu; Biju, Vasudevanpillai; Murase, Norio; Ozaki, Yukihiro

    2013-06-01

    We find unique properties accompanying surface-enhanced fluorescence (SEF) from dye molecules adsorbed on Ag nanoparticle aggregates, which generate surface-enhanced Raman scattering. The properties are observed in excitation laser energy dependence of SEF after excluding plasmonic spectral modulation in SEF. The unique properties are large blue shifts of fluorescence spectra, deviation of ratios between anti-Stokes SEF intensity and Stokes from those of normal fluorescence, super-broadening of Stokes spectra, and returning to original fluorescence by lower energy excitation. We elucidate that these properties are induced by electromagnetic enhancement of radiative decay rates exceeding the vibrational relaxation rates within an electronic excited state, which suggests that molecular electronic dynamics in strong plasmonic fields can be largely deviated from that in free space.

  8. Clinical feasibility of various optical instruments for quantitative evaluation of pulsed-dye laser treatment of port wine stain skin

    NASA Astrophysics Data System (ADS)

    Kim, Chang-Seok; Jung, Byungjo; Choi, Bernard; Verkruysse, Wim; Zhang, Rong; Nelson, John S.

    2005-04-01

    For quantitative prediction and evaluation of pulsed dye laser therapy of port wine stain (PWS) skin, the CIE L*a*b* color difference, ΔE*, has been utilized to characterize numerically the color differences between normal untreated and treated PWS skin. Three optical instruments (Minolta chromameter CR-200, a cross-polarized diffuse reflectance imaging system, and visual reflectance spectrometers) are compared to investigate their clinical feasibility for quantitative color assessment. Compared to the chromameter as a standard measurement instrument, other instruments also provide valuable measurements of skin color for the relative quantification of PWS treatment outcome. The fiber-optic visual reflectance spectrometer is preferable for continuous measurement of a small area of skin. The cross-polarized imaging system is useful as a simple non-contact measurement technique to provide spatially resolved color difference images.

  9. Generation of intense 25-fsec pulses by a pulsed laser system

    SciTech Connect

    Angel, G.; Gagel, R.; Laubereau, A. )

    1989-09-15

    A pulsed femtosecond dye laser is demonstrated with relaxed stability requirements, improved output reproducibility, and significant pulse shortening. Starting with a sequence of {approx}350 pump pulses of a Nd:glass laser (repetition rate 6 Hz, duration 1.3 psec), pulses of 25 fsec and 10 nJ are generated at 566 nm. A non-colliding-pulse, mode-locked ring laser is used with dispersion compensation and the dyes Rhodamine 6G, DQOCI, and DTCI. The evolution of the pulse parameters as a function of cavity round trips is investigated.

  10. Medium performance effect on the high output energy from a xenon lamp-pumped pyrromethene-567 solid-state dye laser

    NASA Astrophysics Data System (ADS)

    Wang, Lei; Chen, De-Ying; Fan, Rong-Wei; He, Wei-Ming

    2012-04-01

    In order to obtain a high output energy from a xenon lamp-pumped solid-state dye laser, homogeneities of laser mediums and flatnesses of medium faces with different processing treatments are discussed in the paper. The mediums without aging treatment, which are prepared by using a prepolymer process and have diamond-machined end faces to produce the required optical finish, give a highest laser output of 281.9 mJ with 0.215% slope efficiency at 2.0 × 10-4 mol/L. The best medium lifetime is 21 shots to 50% of original output equating 74.6 kJ/liter.

  11. ZnO nanowire/reduced graphene oxide nanocomposites for significantly enhanced photocatalytic degradation of Rhodamine 6G

    NASA Astrophysics Data System (ADS)

    Zhang, Chao; Zhang, Jing; Su, Yanjie; Xu, Minghan; Yang, Zhi; Zhang, Yafei

    2014-02-01

    We have demonstrated a facile and low-cost approach to synthesize ZnO nanowire (NW)/reduced graphene oxide (RGO) nanocomposites, in which ZnO NWs and graphene oxide (GO) were produced in large scale separately and then hybridized into ZnO NW/RGO nanocomposites by mechanical mixing and low-temperature thermal reduction. Rhodamine 6G (Rh6G) was used as a model dye to evaluate the photocatalytic properties of ZnO NW/RGO nanocomposites. The obtained nanocomposites show significantly enhanced photocatalytic performance, which took only 10 min to decompose over 98% Rh6G. Finally the mechanism of the great enhancement about photocatalytic activity of ZnO NW/RGO nanocomposites is studied. It is mainly attributed to that RGO nanosheets can transfer the electrons of ZnO NWs excited by ultraviolet (UV) irradiation, increase electron migration efficiency, and then longer the lifetime of the holes in ZnO NWs. The high charge separation efficiency of photo-generated electron-hole pairs directly leads to the lower recombination rate of ZnO NW/RGO nanocomposites, makes more effective electrons and holes to participate the radical reactions with Rh6G, thus significantly improving the photocatalytic properties. The high degradation efficiency makes the ZnO NW/RGO nanocomposites promising candidates in the application of environmental pollutant and wastewater treatment.

  12. The energy transfer mechanism of a photoexcited and electroluminescent organic hybrid thin film of blue, green, and red laser dyes.

    PubMed

    Li, Weiling; Zhang, Jing; Zheng, Yanqiong; Chen, Guo; Cai, Miao; Wei, Bin

    2015-01-01

    Though optically pumped lasing has been realized for years, electrically pumped lasing has not yet been achieved in organic semiconductor devices. In order to make a better understanding of the laser mechanisms of the organic materials, we prepared organic thin films consisting of three efficient laser dyes of a blue emitter, 4″,4″'-N,N-diphenylamine-4,4'-diphenyl-1,1'-binaphthyl (BN), a green emitter, 1,4-bis[2-[4-[N,N-di(p-tolyl)amino] phenyl]vinyl]benzene (DSB), and a red emitter, 4-(dicyanomethylene)-2-t-butyl-6(1,1,7,7-tetramethyljulolidy-l-9-enyl)-4H-pyran (DCJTB) with different doping concentrations for the first time to investigate the cascade energy transfer process. The energy transfer schemes in the co-doped thin films in photoluminescence and electroluminescence have been investigated. The results indicated that the DSB molecules acted as a bridge to deliver energy more effectively from the host (BN) to the guest (DCJTB). Meanwhile, the maximum current efficiency (C E) and power efficiency (P E) of the organic light-emitting devices (OLEDs) with the emitting layer of lower doping concentration were 13.5 cd/A and 14.1 lm/W, respectively.

  13. Synthesis and analysis of nickel dithiolene dyes in a nematic liquid crystal host. 1998 summer research program for high school juniors at the University of Rochester`s Laboratory for Laser Energetics: Student research reports

    SciTech Connect

    Lippa, I.

    1999-03-01

    The Liquid Crystal Point Diffraction Interferometer (LCPDI) can be employed to evaluate the Omega Laser system for optimum firing capabilities. This device utilizes a nickel dithiolene infrared absorbing liquid crystal dye dissolved in a liquid crystal host medium (Merck E7). Three nickel dithiolene dyes were characterized for both their solubility in the E7 host and their infrared spectral absorption.

  14. Broadband optical absorption enhancement of N719 dye in ethanol by gold-silver alloy nanoparticles fabricated under laser ablation technique

    NASA Astrophysics Data System (ADS)

    Al-Azawi, Mohammed A.; Bidin, Noriah; Abbas, Khaldoon N.; Bououdina, Mohamed; Azzez, Shrook A.

    2016-04-01

    The formation of gold-silver alloy nanoparticles (Au-Ag alloy NPs) by a two-step process with a pulsed Nd:YAG laser without any additives is presented. Mixtures of Au and Ag colloidal suspensions were separately obtained by 1064-nm laser ablation of metallic targets immersed in ethanol. Subsequently, the as-mixed colloidal suspensions were reirradiated by laser-induced heating at the second-harmonic generation (532 nm) for different irradiation periods of time. The absorption spectra and morphology of the colloidal alloys were studied as a function of exposure time to laser irradiation. Transmission electron microscopy revealed the formation of monodispersed spherical nanoparticles with a homogeneous size distribution in all the synthesized samples. UV-vis and photoluminescence spectroscopy measurements were also employed to characterize the changes in the light absorption and emission of N719 dye solution with different concentrations of Au-Ag colloidal alloys, respectively. The localized surface plasmon resonance (LSPR) of Au-Ag alloy NPs enhanced the absorption and fluorescence peak of the dye solution. The mixture of dye molecules with a higher concentration of alloy NPs exhibited an additional coupling of dipole moments with the LSPR, thereby contributing to the improvement of the optical properties of the mixture.

  15. Broadband optical absorption enhancement of N719 dye in ethanol by gold-silver alloy nanoparticles fabricated under laser ablation technique

    NASA Astrophysics Data System (ADS)

    Al-Azawi, Mohammed A.; Bidin, Noriah; Abbas, Khaldoon N.; Bououdina, Mohamed; Azzez, Shrook A.

    2016-04-01

    The formation of gold-silver alloy nanoparticles (Au-Ag alloy NPs) by a two-step process with a pulsed Nd:YAG laser without any additives is presented. Mixtures of Au and Ag colloidal suspensions were separately obtained by 1064-nm laser ablation of metallic targets immersed in ethanol. Subsequently, the as-mixed colloidal suspensions were reirradiated by laser-induced heating at the second-harmonic generation (532 nm) for different irradiation periods of time. The absorption spectra and morphology of the colloidal alloys were studied as a function of exposure time to laser irradiation. Transmission electron microscopy revealed the formation of monodispersed spherical nanoparticles with a homogeneous size distribution in all the synthesized samples. UV-vis and photoluminescence spectroscopy measurements were also employed to characterize the changes in the light absorption and emission of N719 dye solution with different concentrations of Au-Ag colloidal alloys, respectively. The localized surface plasmon resonance (LSPR) of Au-Ag alloy NPs enhanced the absorption and fluorescence peak of the dye solution. The mixture of dye molecules with a higher concentration of alloy NPs exhibited an additional coupling of dipole moments with the LSPR, thereby contributing to the improvement of the optical properties of the mixture.

  16. Multimode distributed feedback laser emission in a dye-doped optically pumped polymer thin-film

    NASA Astrophysics Data System (ADS)

    Sobel, F.; Gindre, D.; Nunzi, J.-M.; Denis, C.; Dumarcher, V.; Fiorini-Debuisschert, C.; Kretsch, K. P.; Rocha, L.

    2004-11-01

    We report on particular features of thin film distributed feedback (DFB) lasers. Devices are optically pumped using a Lloyd-mirror interferometer. For a given DFB grating period, the number of lasing modes is film thickness dependent. Spectral content of the devices is analysed using planar waveguide theory. An excellent agreement between the theoretical transverse electric mode structure and the laser emission spectrum is found.

  17. Effect of quencher and temperature on fluorescence intensity of laser dyes: DETC and C504T.

    PubMed

    Jana, Basavaraja; Inamdar, S R; H M, Suresh Kumar

    2017-01-01

    Fluorescence quenching of 7- Diethylamino-3-thenoylcoumarin (DETC) and 2,3,6,7-tetrahydro-1,1,7,7-tetramethyl11-oxo-1H,5H,11H- [1]benzopyrano[6,7,8-ij]quinolizine-10-carboxylic acid, ethyl ester (C504T) by aniline(AN), dimethylaniline (DMA) and diethylaniline (DEA) was investigated in toluene by steady state and transient methods. The quenching parameters like frequency of encounter (kd), probability of quenching per encounter (p), quenching rate parameters (kq) and activation energy of quenching (Ea) were determined experimentally. The kq values determined by steady state and time-resolved methods for the both dyes were found to be same, indicating the dynamic nature of interaction. Magnitudes of p and Ea suggested that the quenching reaction is predominantly controlled by material diffusion. The quenching mechanism is rationalized in terms of electron transfer (ET) from donors (aromatic amines) to the acceptors (coumarin derivatives) confirmed by correlating kq with free energy changes (ΔG°). Further, an effect of temperature on fluorescence intensity was carried out in toluene and methanol solvents. Fluorescence intensity of both the dyes decreases with increase in temperature. Temperature quenching in case of C504T is due to intersystem crossing S1→T2, whereas for DETC, quenching is due to intersystem crossing S1→T2 and ICT→TICT transition. PMID:27423111

  18. Effect of quencher and temperature on fluorescence intensity of laser dyes: DETC and C504T.

    PubMed

    Jana, Basavaraja; Inamdar, S R; H M, Suresh Kumar

    2017-01-01

    Fluorescence quenching of 7- Diethylamino-3-thenoylcoumarin (DETC) and 2,3,6,7-tetrahydro-1,1,7,7-tetramethyl11-oxo-1H,5H,11H- [1]benzopyrano[6,7,8-ij]quinolizine-10-carboxylic acid, ethyl ester (C504T) by aniline(AN), dimethylaniline (DMA) and diethylaniline (DEA) was investigated in toluene by steady state and transient methods. The quenching parameters like frequency of encounter (kd), probability of quenching per encounter (p), quenching rate parameters (kq) and activation energy of quenching (Ea) were determined experimentally. The kq values determined by steady state and time-resolved methods for the both dyes were found to be same, indicating the dynamic nature of interaction. Magnitudes of p and Ea suggested that the quenching reaction is predominantly controlled by material diffusion. The quenching mechanism is rationalized in terms of electron transfer (ET) from donors (aromatic amines) to the acceptors (coumarin derivatives) confirmed by correlating kq with free energy changes (ΔG°). Further, an effect of temperature on fluorescence intensity was carried out in toluene and methanol solvents. Fluorescence intensity of both the dyes decreases with increase in temperature. Temperature quenching in case of C504T is due to intersystem crossing S1→T2, whereas for DETC, quenching is due to intersystem crossing S1→T2 and ICT→TICT transition.

  19. Surface enhanced Raman spectroscopy of individual rhodamine 6G molecules on large Ag nanocrystals

    SciTech Connect

    Michaels, A.M.; Nirmal, M.; Brus, L.E.

    1999-11-03

    To explore the relationship between local electromagnetic field enhancement and the large SERS (surface enhanced Raman scattering) enhancement that enables the observation of single molecule Raman spectra, they measure both resonant Rayleigh scattering spectra and rhodamine 6G Raman spectra from single Ag particles. The apparatus combines the techniques of dark-field optical microscopy for resonant Rayleigh measurements, and grazing incidence Raman spectroscopy. The Rayleigh spectra show that the citrate-reduced Ag colloid is extremely heterogeneous. Only the larger particles, in part created by salt induced aggregation, show a large SERS effect. In agreement with the work of Nie and Emory, a few nanocrystals show huge single molecule R6G SERS intensities. While all SERS active particles have some resonant Rayleigh scattering at the 514.5 nm laser wavelength, there is no correlation between the resonant Rayleigh spectra and the SERS intensity. A model is discussed in which huge SERS intensities result from single chemisorbed molecules interacting with ballistic electrons in optically excited large Ag particles. This model is a natural consequence of the standard local electromagnetic field model for SERS and the high surface sensitivity of plasmon dephasing in the noble metals.

  20. Effectiveness of antimicrobial photodynamic therapy on staphylococcus aureus using phenothiazinium dye with red laser

    NASA Astrophysics Data System (ADS)

    Monteiro, Juliana S. C.; de Oliveira, Susana C. P. S.; Pires-Santos, Gustavo M.; Sampaio, Fernando José P.; Zanin, Fátima Antônia A.; Pinheiro, Antônio L. B.

    2015-03-01

    The aim of this study was to evaluate in vitro the bactericidal effect of Antimicrobial Photodynamic Therapy - AmPDT using a phenothiazinium compound (toluidine blue O and methylene blue, 12.5 μg/mL) on Staphylococcus aureus (ATCC 23529) irradiated or not with the red laser (λ 660 nm, 12J/cm2). All tests were performed in triplicate and samples distributed into the following groups: Negative control, Laser, Photosensitizer, and AmPDT. Bactericidal effect of the Antimicrobial Photodynamic Therapy was assessed by counting of colony-forming units and analyzed statistically (ANOVA, Tukey test, p<0.05). The results showed, comparing the Laser group with Negative control, a statistically significant increase of counting on the Laser group (p = 0.003). The use of the photosensitizer alone reduced the mean number of CFU (64.8%) and its association with the Laser light resulted in 84.2% of inhibition. The results are indicative that the use of Antimicrobial Photodynamic Therapy presented in vitro bactericidal effect on Staphylococcus aureus.

  1. Facile synthesis of silicon carbide-titanium dioxide semiconducting nanocomposite using pulsed laser ablation technique and its performance in photovoltaic dye sensitized solar cell and photocatalytic water purification

    NASA Astrophysics Data System (ADS)

    Gondal, M. A.; Ilyas, A. M.; Baig, Umair

    2016-08-01

    Separation of photo-generated charge carriers (electron and holes) is a major approach to improve the photovoltaic and photocatalytic performance of metal oxide semiconductors. For harsh environment like high temperature applications, ceramic like silicon carbide is very prominent. In this work, 10%, 20% and 40% by weight of pre-oxidized silicon carbide was coupled with titanium dioxide (TiO2) to form nanocomposite semiconductor via elegant pulsed laser ablation in liquid technique using second harmonic 532 nm wavelength of neodymium-doped yttrium aluminium garnet (Nd-YAG) laser. In addition, the effect of silicon carbide concentration on the performance of silicon carbide-titanium dioxide nanocomposite as photo-anode in dye sensitized solar cell and as photocatalyst in photodegradation of methyl orange dye in water was also studied. The result obtained shows that photo-conversion efficiency of the dye sensitized solar cell was improved from 0.6% to 1.65% and the percentage of methyl orange dye removed was enhanced from 22% to 77% at 24 min under ultraviolet-visible solar spectrum in the nanocomposite with 10% weight of silicon carbide. This remarkable performance enhancement could be due to the improvement in electron transfer phenomenon by the presence of silicon carbide on titanium dioxide.

  2. Estimation of ground and excited state dipole moment of laser dyes C504T and C521T using solvatochromic shifts of absorption and fluorescence spectra

    NASA Astrophysics Data System (ADS)

    Basavaraja, Jana; Suresh Kumar, H. M.; Inamdar, S. R.; Wari, M. N.

    2016-02-01

    The absorption and fluorescence spectra of laser dyes: coumarin 504T (C504T) and coumarin 521T (C521T) have been recorded at room temperature in a series of non-polar and polar solvents. The spectra of these dyes showed bathochromic shift with increasing in solvent polarity indicating the involvement of π → π* transition. Kamlet-Taft and Catalan solvent parameters were used to analyze the effect of solvents on C504T and C521T molecules. The study reveals that both general solute-solvent interactions and specific interactions are operative in these two systems. The ground state dipole moment was estimated using Guggenheim's method and also by quantum mechanical calculations. The solvatochromic data were used to determine the excited state dipole moment (μe). It is observed that dipole moment value of excited state (μe) is higher than that of the ground state in both the laser dyes indicating that these dyes are more polar in nature in the excited state than in the ground state.

  3. Investigations on the growth, optical, thermal, dielectric, and laser damage threshold properties of crystal violet dye-doped potassium acid phthalate single crystal

    NASA Astrophysics Data System (ADS)

    Rao, G. Babu; Rajesh, P.; Ramasamy, P.

    2016-03-01

    Influence of crystal violet dye with different concentration on potassium acid phthalate single crystal grown by conventional method has been studied. No change has been observed in the structure, whereas changes have been observed in the external morphology of the crystal when the dyes are incorporated in the crystal lattice. Thermogravimetric and differential thermal analyses show the onset decomposition temperatures to be at 302, 285, 284, and 285 °C for pure, 0.1, 0.3, and 0.5 mol% crystal violet-doped potassium acid phthalate crystals, respectively. The dielectric measurement was carried out on the grown crystals as a function of frequency at various temperatures. In addition, strong luminescent emission bands at 638, 648, and 640 nm were observed in which the relative intensity was found to be reversed as a result of doping concentration. The laser damage threshold value significantly increased for dye-doped crystal in comparison with pure crystal which may make it suitable for the solid-state dye laser applications.

  4. Evaluation of quantum dot immunofluorescence and a digital CMOS imaging system as an alternative to conventional organic fluorescence dyes and laser scanning for quantifying protein microarrays.

    PubMed

    Jain, Aarti; Taghavian, Omid; Vallejo, Derek; Dotsey, Emmanuel; Schwartz, Dan; Bell, Florian G; Greef, Chad; Davies, D Huw; Grudzien, Jennipher; Lee, Abraham P; Felgner, Philip L; Liang, Li

    2016-04-01

    Organic fluorescent dyes are widely used for the visualization of bound antibody in a variety of immunofluorescence assays. However, the detection equipment is often expensive, fragile, and hard to deploy widely. Quantum dots (Qdot) are nanocrystals made of semiconductor materials that emit light at different wavelengths according to the size of the crystal, with increased brightness and stability. Here, we have evaluated a small benchtop "personal" optical imager (ArrayCAM) developed for quantification of protein arrays probed by Qdot-based indirect immunofluorescence. The aim was to determine if the Qdot imager system provides equivalent data to the conventional organic dye-labeled antibody/laser scanner system. To do this, duplicate proteome microarrays of Vaccinia virus, Brucella melitensis and Plasmodium falciparum were probed with identical samples of immune sera, and IgG, IgA, and IgM profiles visualized using biotinylated secondary antibodies followed by a tertiary reagent of streptavidin coupled to either P3 (an organic cyanine dye typically used for microarrays) or Q800 (Qdot). The data show excellent correlation for all samples tested (R > 0.8) with no significant change of antibody reactivity profiles. We conclude that Qdot detection provides data equivalent to that obtained using conventional organic dye detection. The portable imager offers an economical, more robust, and deployable alternative to conventional laser array scanners. PMID:26842269

  5. Extensive angiokeratoma circumscriptum - successful treatment with 595-nm variable-pulse pulsed dye laser and 755-nm long-pulse pulsed alexandrite laser.

    PubMed

    Baumgartner, Ján; Šimaljaková, Mária; Babál, Pavel

    2016-06-01

    Angiokeratomas are rare vascular mucocutaneous lesions characterized by small-vessel ectasias in the upper dermis with reactive epidermal changes. Angiokeratoma circumscriptum (AC) is the rarest among the five types in the current classification of angiokeratoma. We present a case of an extensive AC in 19-year-old women with Fitzpatrick skin type I of the left lower extremity, characterized by a significant morphological heterogeneity of the lesions, intermittent bleeding, and negative psychological impact. Histopathological examination after deep biopsy was consistent with that of angiokeratoma. The association with metabolic diseases (Fabry disease) was excluded by ophthalmological, biochemical, and genetic examinations. Nuclear magnetic resonance imaging has not detected deep vascular hyperplasia pathognomic for verrucous hemangioma. The combined treatment with 595-nm variable-pulse pulsed dye laser (VPPDL) and 755-nm long-pulse pulsed alexandrite laser (LPPAL) with dynamic cooling device led to significant removal of the pathological vascular tissue of AC. Only a slight degree of secondary reactions (dyspigmentations and texture changes) occurred. No recurrence was observed after postoperative interval of 9 months. We recommend VPPDL and LPPAL for the treatment of extensive AC.

  6. Extensive angiokeratoma circumscriptum - successful treatment with 595-nm variable-pulse pulsed dye laser and 755-nm long-pulse pulsed alexandrite laser.

    PubMed

    Baumgartner, Ján; Šimaljaková, Mária; Babál, Pavel

    2016-06-01

    Angiokeratomas are rare vascular mucocutaneous lesions characterized by small-vessel ectasias in the upper dermis with reactive epidermal changes. Angiokeratoma circumscriptum (AC) is the rarest among the five types in the current classification of angiokeratoma. We present a case of an extensive AC in 19-year-old women with Fitzpatrick skin type I of the left lower extremity, characterized by a significant morphological heterogeneity of the lesions, intermittent bleeding, and negative psychological impact. Histopathological examination after deep biopsy was consistent with that of angiokeratoma. The association with metabolic diseases (Fabry disease) was excluded by ophthalmological, biochemical, and genetic examinations. Nuclear magnetic resonance imaging has not detected deep vascular hyperplasia pathognomic for verrucous hemangioma. The combined treatment with 595-nm variable-pulse pulsed dye laser (VPPDL) and 755-nm long-pulse pulsed alexandrite laser (LPPAL) with dynamic cooling device led to significant removal of the pathological vascular tissue of AC. Only a slight degree of secondary reactions (dyspigmentations and texture changes) occurred. No recurrence was observed after postoperative interval of 9 months. We recommend VPPDL and LPPAL for the treatment of extensive AC. PMID:26736060

  7. Pulsed dye laser does not seem as effective as red light in Basal cell carcinoma mal-pdt: a small pilot study.

    PubMed

    Fernández-Guarino, M; Harto, A; Jaén, P

    2012-01-01

    Multiple light sources can be used for photodynamic therapy (PDT) with good results, but there are few comparative studies. This study compares the efficacy of treatment of basal cell carcinoma with PDT and two light sources, the non-coherent red light and pulsed dye laser 595 nm. In this small pilot study red light is more effective, but many more studies are needed to draw definitive conclusions.

  8. Pulsed Dye Laser Does Not Seem as Effective as Red Light in Basal Cell Carcinoma Mal-Pdt: A Small Pilot Study

    PubMed Central

    Fernández-Guarino, M.; Harto, A.; Jaén, P.

    2012-01-01

    Multiple light sources can be used for photodynamic therapy (PDT) with good results, but there are few comparative studies. This study compares the efficacy of treatment of basal cell carcinoma with PDT and two light sources, the non-coherent red light and pulsed dye laser 595 nm. In this small pilot study red light is more effective, but many more studies are needed to draw definitive conclusions. PMID:23209908

  9. Argon-pumped tunable dye laser therapy for facial port-wine stain hemangiomas in adults--a new technique using small spot size and minimal power

    SciTech Connect

    Scheibner, A.; Wheeland, R.G.

    1989-03-01

    A low power, argon-pumped tunable dye laser was used to deliver yellow light of 577 nm. Individual blood vessels within port-wine stain hemangiomas were treated with a 0.1-mm beam of light using 8 X magnification. This technique permits excellent resolution of facial and nuchal port-wine stain hemangiomas in adults without the adverse complications of textural change, permanent pigmentation abnormality, or hypertrophic scarring.

  10. Pulsed laser deposited porous nano-carpets of indium tin oxide and their use as charge collectors in core-shell structures for dye sensitized solar cells

    NASA Astrophysics Data System (ADS)

    Garvey, Timothy R.; Farnum, Byron H.; Lopez, Rene

    2015-01-01

    Porous In2O3:Sn (ITO) films resembling from brush carpets to open moss-like discrete nanostructures were grown by pulsed laser deposition under low to high background gas pressures, respectively. The charge transport properties of these mesoporous substrates were probed by pulsed laser photo-current and -voltage transient measurements in N719 dye sensitized devices. Although the cyclic voltammetry and dye adsorption measurements suggest a lower proportion of electro-active dye molecules for films deposited at the high-end background gas pressures, the transient measurements indicate similar electron transport rates within the films. Solar cell operation was achieved by the deposition of a conformal TiO2 shell layer by atomic layer deposition (ALD). Much of the device improvement was shown to be due to the TiO2 shell blocking the recombination of photoelectrons with the electrolyte as recombination lifetimes increased drastically from a few seconds in uncoated ITO to over 50 minutes in the ITO with a TiO2 shell layer. Additionally, an order of magnitude increase in the electron transport rate in ITO/TiO2 (core/shell) films was observed, giving the core-shell structure a superior ratio of recombination/transport times.Porous In2O3:Sn (ITO) films resembling from brush carpets to open moss-like discrete nanostructures were grown by pulsed laser deposition under low to high background gas pressures, respectively. The charge transport properties of these mesoporous substrates were probed by pulsed laser photo-current and -voltage transient measurements in N719 dye sensitized devices. Although the cyclic voltammetry and dye adsorption measurements suggest a lower proportion of electro-active dye molecules for films deposited at the high-end background gas pressures, the transient measurements indicate similar electron transport rates within the films. Solar cell operation was achieved by the deposition of a conformal TiO2 shell layer by atomic layer deposition (ALD). Much

  11. Comparison and mechanism of photocatalytic activities of N-ZnO and N-ZrO2 for the degradation of rhodamine 6G.

    PubMed

    Sudrajat, Hanggara; Babel, Sandhya

    2016-05-01

    N-doped ZnO (N-ZnO) and N-doped ZrO2 (N-ZrO2) are synthesized by novel, simple thermal decomposition methods. The catalysts are evaluated for the degradation of rhodamine 6G (R6G) under visible and UV light. N-ZnO exhibits higher dye degradation under both visible and UV light compared to N-ZrO2 due to possessing higher specific surface area, lower crystalline size, and lower band gap. However, it is less reusable than N-ZrO2 and its photocatalytic activity is also deteriorated at low pH. At the same intensity of 3.5 W/m(2), UVC light is shown to be a better UV source for N-ZnO, while UVA light is more suitable for N-ZrO2. At pH 7 with initial dye concentration of 10 mg/L, catalyst concentration of 1 g/L, and UVC light, 94.3 % of R6G is degraded by N-ZnO within 2 h. Using UVA light under identical experimental conditions, 93.5 % degradation of R6G is obtained by N-ZrO2. Moreover, the type of light source is found to determine the reactive species produced in the R6G degradation by N-ZnO and N-ZrO2. Less oxidative reactive species such as superoxide radical and singlet oxygen play a major role in the degradation of R6G under visible light. On the contrary, highly oxidative hydroxyl radicals are predominant under UVC light. Based on the kinetic study, the adsorption of R6G on the catalyst surface is found to be the controlling step.

  12. Comparison and mechanism of photocatalytic activities of N-ZnO and N-ZrO2 for the degradation of rhodamine 6G.

    PubMed

    Sudrajat, Hanggara; Babel, Sandhya

    2016-05-01

    N-doped ZnO (N-ZnO) and N-doped ZrO2 (N-ZrO2) are synthesized by novel, simple thermal decomposition methods. The catalysts are evaluated for the degradation of rhodamine 6G (R6G) under visible and UV light. N-ZnO exhibits higher dye degradation under both visible and UV light compared to N-ZrO2 due to possessing higher specific surface area, lower crystalline size, and lower band gap. However, it is less reusable than N-ZrO2 and its photocatalytic activity is also deteriorated at low pH. At the same intensity of 3.5 W/m(2), UVC light is shown to be a better UV source for N-ZnO, while UVA light is more suitable for N-ZrO2. At pH 7 with initial dye concentration of 10 mg/L, catalyst concentration of 1 g/L, and UVC light, 94.3 % of R6G is degraded by N-ZnO within 2 h. Using UVA light under identical experimental conditions, 93.5 % degradation of R6G is obtained by N-ZrO2. Moreover, the type of light source is found to determine the reactive species produced in the R6G degradation by N-ZnO and N-ZrO2. Less oxidative reactive species such as superoxide radical and singlet oxygen play a major role in the degradation of R6G under visible light. On the contrary, highly oxidative hydroxyl radicals are predominant under UVC light. Based on the kinetic study, the adsorption of R6G on the catalyst surface is found to be the controlling step. PMID:26873829

  13. The use of vitamins as tracer dyes for laser-induced fluorescence in liquid flow applications

    NASA Astrophysics Data System (ADS)

    Zähringer, Katharina

    2014-04-01

    Tracers commonly used in experimental flow studies are mostly nocuous to the environment and human health. Particularly, in large flow installations, this can become a problem. In this study, a solution of this problem is presented, based on using water-soluble vitamins. Five of them are examined here for their applicability in flow studies. Vitamins B2 and B6 turned out to be the most promising candidates, and the dependency of their fluorescence intensity on parameters like concentration, laser energy, temperature, and pH are determined for two commonly used laser excitation wavelengths (532, 355 nm). Two examples of application in a static mixer and a spray flow are shown and demonstrate the applicability of the vitamin tracers.

  14. Comparing Quantitative Values of Two Generations of Laser-Assisted Indocyanine Green Dye Angiography Systems: Can We Predict Necrosis?

    PubMed Central

    Fourman, Mitchell S.; Rivara, Andrew; Dagum, Alexander B.; Huston, Tara L.; Ganz, Jason C.; Bui, Duc T.; Khan, Sami U.

    2014-01-01

    Objective: Several devices exist today to assist the intraoperative determination of skin flap perfusion. Laser-Assisted Indocyanine Green Dye Angiography (LAICGA) has been shown to accurately predict mastectomy skin flap necrosis using quantitative perfusion values. The laser properties of the latest LAICGA device (SPY Elite) differ significantly from its predecessor system (SPY 2001), preventing direct translation of previous published data. The purpose of this study was to establish a mathematical relationship of perfusion values between these 2 devices. Methods: Breast reconstruction patients were prospectively enrolled into a clinical trial where skin flap evaluation and excision was based on quantitative SPY Q values previously established in the literature. Initial study patients underwent mastectomy skin flap evaluation using both SPY systems simultaneously. Absolute perfusion unit (APU) values at identical locations on the breast were then compared graphically. Results: 210 data points were identified on the same patients (n = 4) using both SPY systems. A linear relationship (y = 2.9883x + 12.726) was identified with a high level or correlation (R2 = 0.744). Previously published values using SPY 2001 (APU 3.7) provided a value of 23.8 APU on the SPY Elite. In addition, postoperative necrosis in these patients correlated to regions of skin identified with the SPY Elite with APU less than 23.8. Conclusion: Intraoperative comparison of LAICGA systems has provided direct correlation of perfusion values predictive of necrosis that were previously established in the literature. An APU value of 3.7 from the SPY 2001 correlates to a SPY Elite APU value of 23.8. PMID:25525483

  15. Rotational motion of rhodamine 6G tethered to actin through oligo(ethylene glycol) linkers studied by frequency-domain fluorescence anisotropy.

    PubMed

    Wazawa, Tetsuichi; Morimoto, Nobuyuki; Nagai, Takeharu; Suzuki, Makoto

    2015-01-01

    Investigation of the rotational motion of a fluorescent probe tethered to a protein helps to elucidate the local properties of the solvent and protein near the conjugation site of the probe. In this study, we have developed an instrument for frequency-domain fluorescence (FDF) anisotropy measurements, and studied how the local properties around a protein, actin, can be elucidated from the rotational motion of a dye tethered to actin. Rhodamine 6G (R6G) was attached to Cys-374 using newly-synthesized R6G-maleimide with three different oligo(ethylene glycol) (OEG) linker lengths. The time-resolved anisotropy decay of R6G tethered to G-actin was revealed to be a combination of the two modes of the wobbling motion of R6G and the tumbling motion of G-actin. The rotational diffusion coefficient (RDC) of R6G wobbling was ~0.1 ns(-1) at 20°C and increased with OEG linker length. The use of the three R6G-actin conjugates of different linker lengths was useful to not only figure out the linker length dependence of the rotational motion of R6G but also validate the analyses. In the presence of a cosolvent of glycerol, although the tumbling motion of G-actin was retarded in response to the bulk viscosity, the wobbling motion of R6G tethered to actin exhibited an increase of RDC as glycerol concentration increased. This finding suggests an intricate relationship between the fluid properties of the bulk solvent and the local environment around actin.

  16. Rotational motion of rhodamine 6G tethered to actin through oligo(ethylene glycol) linkers studied by frequency-domain fluorescence anisotropy

    PubMed Central

    Wazawa, Tetsuichi; Morimoto, Nobuyuki; Nagai, Takeharu; Suzuki, Makoto

    2015-01-01

    Investigation of the rotational motion of a fluorescent probe tethered to a protein helps to elucidate the local properties of the solvent and protein near the conjugation site of the probe. In this study, we have developed an instrument for frequency-domain fluorescence (FDF) anisotropy measurements, and studied how the local properties around a protein, actin, can be elucidated from the rotational motion of a dye tethered to actin. Rhodamine 6G (R6G) was attached to Cys-374 using newly-synthesized R6G-maleimide with three different oligo(ethylene glycol) (OEG) linker lengths. The time-resolved anisotropy decay of R6G tethered to G-actin was revealed to be a combination of the two modes of the wobbling motion of R6G and the tumbling motion of G-actin. The rotational diffusion coefficient (RDC) of R6G wobbling was ~0.1 ns−1 at 20°C and increased with OEG linker length. The use of the three R6G-actin conjugates of different linker lengths was useful to not only figure out the linker length dependence of the rotational motion of R6G but also validate the analyses. In the presence of a cosolvent of glycerol, although the tumbling motion of G-actin was retarded in response to the bulk viscosity, the wobbling motion of R6G tethered to actin exhibited an increase of RDC as glycerol concentration increased. This finding suggests an intricate relationship between the fluid properties of the bulk solvent and the local environment around actin. PMID:27493858

  17. Optical multichannel recorder and its application in studying a picosecond dye laser

    SciTech Connect

    Vinogradov, S.V.; Kuznetsov, V.V.; Lyutinskii, V.V.; Nazarov, V.N.; Neporent, B.S.; Nikolaev, G.E.; Poznyak, R.I.; Revinskii, V.V.; Sokolov, A.V.; Tovmasyan, S.K.; Chernyavskii, A.F.

    1987-09-01

    The authors created and applied an optical multichannel recorder with a PZS matrix detector for investigating the parameters of laser radiation. The instrument, called on OMR (optical multichannel recorder), records the spatial intensity distribution of a radiation pulse incident on the detector, memorizes it, reproduces it in the form of a semitone map on a television display, and outputs the signal intensity at any point, the intensity distribution over a given cross-section (line), and the integral over the cross section to a digital display.

  18. Double-label immunofluorescence with the laser scanning confocal microscope using cyanine dyes.

    PubMed

    Sargent, P B

    1994-11-01

    The laser scanning confocal microscope, when used with the krypton-argon ion laser, is well suited for the simultaneous detection of pairs of antigens by immunofluorescence. Traditionally, double-label studies have utilized secondary antibodies conjugated to fluorescein isothiocyanate (FITC), excited by the 488-nm line (blue), and to tetramethyl rhodamine isothiocyanate or Texas Red, excited by the 568-nm line (yellow). However, the use of fluorophores excited by the 488 nm line produces unsatisfactory results when tissue contains low wavelength-excitable autofluorescence. In the amphibian cardiac ganglion, for example, autofluorescent granules within parasympathetic neurons obscure cell surface-derived signals and prevent one from analyzing the relative position of acetylcholine receptor clusters and synaptic boutons by double-label immunofluorescence. This problem has been solved by using cyanine 3.18 (Cy3)- and cyanine 5.18 (Cy5)-conjugated secondary antibodies, which are excited efficiently by the 568-nm (yellow) and the 647-nm (red) lines and which emit in the orange/red and in the far-red, respectively, and thus by avoiding the 488-nm line altogether. The resulting images are as good or better than those obtained with FITC and Texas Red, even without consideration of autofluorescence.

  19. Laser synthesized super-hydrophobic conducting carbon with broccoli-type morphology as a counter-electrode for dye sensitized solar cells

    NASA Astrophysics Data System (ADS)

    Gokhale, Rohan; Agarkar, Shruti; Debgupta, Joyashish; Shinde, Deodatta; Lefez, Benoit; Banerjee, Abhik; Jog, Jyoti; More, Mahendra; Hannoyer, Beatrice; Ogale, Satishchandra

    2012-10-01

    A laser photochemical process is introduced to realize superhydrophobic conducting carbon coatings with broccoli-type hierarchical morphology for use as a metal-free counter electrode in a dye sensitized solar cell. The process involves pulsed excimer laser irradiation of a thin layer of liquid haloaromatic organic solvent o-dichlorobenzene (DCB). The coating reflects a carbon nanoparticle-self assembled and process-controlled morphology that yields solar to electric power conversion efficiency of 5.1% as opposed to 6.2% obtained with the conventional Pt-based electrode.A laser photochemical process is introduced to realize superhydrophobic conducting carbon coatings with broccoli-type hierarchical morphology for use as a metal-free counter electrode in a dye sensitized solar cell. The process involves pulsed excimer laser irradiation of a thin layer of liquid haloaromatic organic solvent o-dichlorobenzene (DCB). The coating reflects a carbon nanoparticle-self assembled and process-controlled morphology that yields solar to electric power conversion efficiency of 5.1% as opposed to 6.2% obtained with the conventional Pt-based electrode. Electronic supplementary information (ESI) available: Materials and equipment details, solar cell fabrication protocol, electrolyte spreading time measurement details, XPS spectra, electronic study, film adhesion test detailed analysis and field emission results. See DOI: 10.1039/c2nr32082g

  20. Vertical-cavity surface-emitting laser in the long-wavelength (700 nm) region in the visible by energy transfer between organic dyes

    NASA Astrophysics Data System (ADS)

    Liao, Zhifu; Zhou, Yuan; Cui, Yuanjing; Yang, Yu; Wang, Zhiyu; Qian, Guodong

    2014-06-01

    In this work, organic vertical-cavity surface-emitting lasers (VCSELs) with single-mode laser output in the long-wavelength region (~700 nm) of the visible were reported based on the energy transfer between dye pairs consisting of pyrromethene 597 (PM597) and rhodamine 700 (LD700). By co-doping PM597 into the polymeric hosts, the fluorescence intensity of LD700 was enhanced by 30-fold and the photophysical parameters of the donor-acceptor pairs were investigated, indicating the involvement of non-radiative resonance energy transfer processes between PM597 and LD700. Active distributed Bragg reflectors (DBR) were made by alternately spin-coating dye-doped polyvinylcarbazole and cellulose acetate thin films as the high and low refractive index layers, respectively. By sandwiching the active layer with 2 DBR mirrors, VCSEL emission at 698.9 nm in the biological first window (650-950 nm) was observed under the 532-nm laser pulses. The laser slope efficiency and threshold were also measured.

  1. How does the surface charge of ionic surfactant and cholesterol forming vesicles control rotational and translational motion of rhodamine 6G perchlorate (R6G ClO₄)?

    PubMed

    Ghosh, Surajit; Roy, Arpita; Banik, Debasis; Kundu, Niloy; Kuchlyan, Jagannath; Dhir, Anjali; Sarkar, Nilmoni

    2015-03-01

    The rotational dynamics and translational diffusion of a hydrophilic organic molecule, rhodamine 6G perchlorate (R6G ClO4) in small unilamellar vesicles formed by two different ionic surfactants, cetyltrimethylammonium bromide (CTAB) and sodium dodecyl sulfate (SDS), with cholesterol have been investigated using fluorescence spectroscopic methods. Moreover, in this article the formation of vesicle using anionic surfactant, SDS at different cholesterol-to-surfactant molar ratio (expressed by Q value (Q = [cholesterol]/[surfactant])) has also been reported. Visual observation, dynamic light scattering (DLS) study, turbidity measurement, steady state fluorescence anisotropy (r0) measurement, and eventually microscopic images reveal the formation of small unilamellar vesicles in aqueous solution. Also, in this study, an attempt has been made to observe whether the cationic probe molecule, rhodamine 6G (R6G) experiences similar or different microenvironment in cholesterol-SDS and cholesterol-CTAB assemblies with increase in cholesterol concentration. The influence of cholesterol on rotational and translational diffusion of R6G molecules has been investigated by monitoring UV-vis absorption, fluorescence, time-resolved fluorescence anisotropy, and finally fluorescence correlation spectroscopy (FCS) measurements. In cholesterol-SDS assemblies, due to the strong electrostatic attractive interaction between the negatively charged surface of vesicle and cationic R6G molecules, the rotational and diffusion motion of R6G becomes slower. However, in cholesterol-CTAB aggregates, the enhanced hydrophobicity and electrostatic repulsion induces the migration of R6G from vesicle bilayer to aqueous phase. The experimental observations suggest that the surface charge of vesicles has a stronger influence than the hydrophobicity of the vesicle bilayer on the rotational and diffusion motion of R6G molecules.

  2. Pulsed laser deposited porous nano-carpets of indium tin oxide and their use as charge collectors in core-shell structures for dye sensitized solar cells.

    PubMed

    Garvey, Timothy R; Farnum, Byron H; Lopez, Rene

    2015-02-14

    Porous In2O3:Sn (ITO) films resembling from brush carpets to open moss-like discrete nanostructures were grown by pulsed laser deposition under low to high background gas pressures, respectively. The charge transport properties of these mesoporous substrates were probed by pulsed laser photo-current and -voltage transient measurements in N719 dye sensitized devices. Although the cyclic voltammetry and dye adsorption measurements suggest a lower proportion of electro-active dye molecules for films deposited at the high-end background gas pressures, the transient measurements indicate similar electron transport rates within the films. Solar cell operation was achieved by the deposition of a conformal TiO2 shell layer by atomic layer deposition (ALD). Much of the device improvement was shown to be due to the TiO2 shell blocking the recombination of photoelectrons with the electrolyte as recombination lifetimes increased drastically from a few seconds in uncoated ITO to over 50 minutes in the ITO with a TiO2 shell layer. Additionally, an order of magnitude increase in the electron transport rate in ITO/TiO2 (core/shell) films was observed, giving the core-shell structure a superior ratio of recombination/transport times.

  3. Comparison of TiO₂ and ZnO solar cells sensitized with an indoline dye: time-resolved laser spectroscopy studies of partial charge separation processes.

    PubMed

    Sobuś, Jan; Burdziński, Gotard; Karolczak, Jerzy; Idígoras, Jesús; Anta, Juan A; Ziółek, Marcin

    2014-03-11

    Time-resolved laser spectroscopy techniques in the time range from femtoseconds to seconds were applied to investigate the charge separation processes in complete dye-sensitized solar cells (DSC) made with iodide/iodine liquid electrolyte and indoline dye D149 interacting with TiO2 or ZnO nanoparticles. The aim of the studies was to explain the differences in the photocurrents of the cells (3-4 times higher for TiO2 than for ZnO ones). Electrochemical impedance spectroscopy and nanosecond flash photolysis studies revealed that the better performance of TiO2 samples is not due to the charge collection and dye regeneration processes. Femtosecond transient absorption results indicated that after first 100 ps the number of photoinduced electrons in the semiconductor is 3 times higher for TiO2 than for ZnO solar cells. Picosecond emission studies showed that the lifetime of the D149 excited state is about 3 times longer for ZnO than for TiO2 samples. Therefore, the results indicate that lower performance of ZnO solar cells is likely due to slower electron injection. The studies show how to correlate the laser spectroscopy methodology with global parameters of the solar cells and should help in better understanding of the behavior of alternative materials for porous electrodes for DSC and related devices.

  4. Laser-excited fluorescence spectra of atomic uranium

    SciTech Connect

    Wang Songyue; Jin Changtai; Shen Mingtao; Wang Xiulan

    1987-05-01

    Using a dc-supply hollow-cathode lamp as a source of uranium vapor and a rhodamine 6G dye laser to excite the vapor optically, it was simple and convenient to detect fluorescence from uranium atoms at 753.393, 763.175, and 763.954 nm. We give a detailed discussion of how we eliminated the intense background emissions, which were principally due to the lamp.

  5. Ablation of intervertebral discs in dogs using a MicroJet-assisted dye-enhanced injection device coupled with the diode laser

    NASA Astrophysics Data System (ADS)

    Bartels, Kenneth E.; Henry, George A.; Dickey, D. Thomas; Stair, Ernest L.; Powell, Ronald; Schafer, Steven A.; Nordquist, Robert E.; Frederickson, Christopher J.; Hayes, Donald J.; Wallace, David B.

    1998-07-01

    Use of holmium laser energy for vaporization/coagulation of the nucleus pulposus in canine intervertebral discs has been previously reported and is currently being applied clinically in veterinary medicine. The procedure was originally developed in the canine model and intended for potential human use. Since the pulsed (15 Hz) holmium laser energy exerts photomechanical and photothermal effects, the potential for extrusion of additional disc material to the detriment of the patient is possible using the procedure developed for the dog. To reduce this potential complication, use of diode laser (805 nm - CW mode) energy, coupled with indocyanine green (ICG) as a selective laser energy absorber, was formulated as a possible alternative. Delivery of the ICG and diode laser energy was through a MicroJet device that could dispense dye interactively between individual laser 'shots.' Results have shown that it is possible to selectively ablate nucleus pulposus in the canine model using the device described. Acute observations (gross and histopathologic) illustrate that accurate placement of the spinal needle before introduction of the MicroJet device is critically dependent on the expertise of the interventional radiologist. In addition, the success of the overall technique depends on consistent delivery of both ICG and diode laser energy. Minimizing tissue carbonization on the tip of the MicroJet device is also of crucial importance for effective application of the technique in clinical veterinary medicine.

  6. The effect of pulsed dye laser on high-risk basal cell carcinomas with response control by Mohs micrographic surgery.

    PubMed

    Alonso-Castro, Leticia; Ríos-Buceta, Luis; Boixeda, Pablo; Paoli, John; Moreno, Carmen; Jaén, Pedro

    2015-09-01

    Several reports have shown the effectiveness of pulsed dye laser (PDL) for the treatment of basal cell carcinoma (BCC). Most studies have focused on low-risk BCCs, but an important limitation has been the lack of histologic confirmation of the treatment results. The aim of this study was to assess the effectiveness of PDL in high-risk BCCs with complete histologic evaluation with Mohs micrographic surgery (MMS). Seven patients with high-risk BCCs located on the face were included. All tumors were treated with three sessions of PDL (595 nm) at 4-week intervals. The tumor and 4 mm of peripheral skin were treated with two stacked pulses with a 1-s delay, a fluence of 15 J/cm(2), a pulse duration of 2 ms, and a spot size of 7 mm. MMS was performed at least 1 month after the last PDL session including excisional tumor debulking prior to the first stage of MMS for standard histologic evaluation. Apparent complete clinical response was achieved in five of seven patients. MMS was finally performed in six patients, and clear margins were achieved after one stage of MMS. The histologic evaluation of the tumor debulking specimens showed complete clearance in four of six cases. One patient who did not undergo MMS showed a recurrence after 14 months. This is the first pilot study that demonstrates that PDL can be effective for the treatment of high-risk BCCs. Until further scientific evidence is available, treatment of high-risk BCCs should include histologic confirmation of clearance.

  7. Lipidomics for clinical diagnosis: Dye-Assisted Laser Desorption/Ionization (DALDI) method for lipids detection in MALDI mass spectrometry imaging.

    PubMed

    Arafah, Karim; Longuespée, Rémi; Desmons, Annie; Kerdraon, Olivier; Fournier, Isabelle; Salzet, Michel

    2014-08-01

    Lipid-based biomarkers for research and diagnosis are rapidly emerging to unpack the basis of person-to-person and population variations in disease susceptibility, drug and nutritional responses, to name but a few. Hence, with the advent of MALDI Mass Spectrometry Imaging, lipids have begun to be investigated intensively. However, lipids are highly mobile during tissue preparation, and are soluble in the solvent used for matrix preparation or in the fixing fluid such as formalin, resulting in substantial delocalization. In the present article, we investigated as another alternative, the possibility of using specific dyes that can absorb UV wavelengths, in order to desorb the lipids specifically from tissue sections, and are known to immobilize them in tissues. Indeed, after lipid insolubilization with chromate solution or chemical fixation with osmium tetroxide, heterocyclic-based dyes can be directly used without matrix. Taking into account the fact that some dyes have this matrix-free capability, we identified particular dyes dedicated to histological staining of lipids that could be used with MALDI mass spectrometry imaging. We stained tissue sections with either Sudan Black B, Nile Blue A, or Oil Red O. An important advantage of this assay relies on its compatibility with usual practices of histopathological investigation of lipids. As a new method, DALDI stands for Dye-Assisted Laser Desorption Ionization and allows for future clinical and histopathological applications using routine histological protocols. Additionally, this novel methodology was validated in human ovarian cancer biopsies to demonstrate its use as a suitable procedure, for histological diagnosis in lipidomics field. PMID:24905741

  8. The UV and Laser Aging for PMMA/BDK/Azo-dye Polymer Blend Cured by UV Light Beams

    NASA Astrophysics Data System (ADS)

    Ahmad, A. A.; Omari, A. M.

    2015-10-01

    A polymeric-based solution blend composed of Azo-dye methyl red (MR) doped with polymethelmethacrelate (PMMA) solution, in addition, to the BenzylDimethylKetal (BDK) photoinitiator was made with optimum molar ratios and deposited on glass substrate by spin coating technique. The samples were then exposed to UV light beams in order to assist the layers polymerization by the proper exposure process. The photo chemical reaction occurred during the UV light polymerization process induces photo refractive changes which were presented as a function of wavelength or photon energy. Two main strong absorption peaks were observed in the films at around 330 nm (3.75 eV) and 500 nm (2.48 eV) for different curing time periods. This phenomenon enhances the films usage for optical data storage media at these two wavelengths. Since the deposited films were then useful as based layers for Read/Write optical data storage media, they were then tested by UV or laser Read/Write beams independently. The optical properties of the films were investigated while exposed to each beam. Finally, their optical properties were investigated as a function of aging time in order to relate the temporary and/or permanent light-exposure effect on the films compared to their optical properties before the light exposure. The films show a low absorbance at 630 nm (1.97 eV) and high absorbance at 480 nm (2.58 eV). This fact makes it possible to record holographic gratings in the polymeric film upon light exposure. In all cases the optical properties were evaluated by using the very sensitive, non destructive surface testing spectroscopic ellipsometry technique. The films were characterized in the spectral range of 300 to 1000 nm using Lorentz oscillator model with one oscillator centred at 4.15 eV. This study has been supported by the SEM and EDAX results to investigate the effect of the UV and visible beams on their optical properties. The results of this research determined the proper conditions for

  9. Giant unilamellar vesicles containing Rhodamine 6G as a marker for immunoassay of bovine serum albumin and lipocalin-2.

    PubMed

    Sakamoto, Misato; Shoji, Atsushi; Sugawara, Masao

    2016-07-15

    Functionalized giant unilamellar vesicles (GUVs) containing a fluorescence dye Rhodamine 6G is proposed as a marker in sandwich-type immunoassay for bovine serum albumin (BSA) and lipocalin-2 (LCN2). The GUVs were prepared by the electroformation method and functionalized with anti-BSA antibody and anti-LCN2 antibody, respectively. The purification of antibody-modified GUVs was achieved by conventional centrifugation and a washing step in a flow system. To antigen on an antibody slip, antibody-modified GUVs were added as a marker and incubated. After wash-out of excess reagents and lysis of the bound GUVs with Triton X-100, the fluorescence image was captured. The fluorometric immunoassays for BSA and LCN2 exhibited lower detection limits of 4 and 80 fg ml(-)(1), respectively. PMID:27117116

  10. Lasers of All Sizes

    NASA Astrophysics Data System (ADS)

    Balcou, Philippe; Forget, Sébastien Robert-Philip, Isabelle

    2015-10-01

    * Introduction * The Laser in All Its Forms * Gas lasers * Dye lasers * Solid-state lasers * Lasers for Every Taste * The rise of lasers * Lasers of all sizes * The colors of the rainbow... and beyond * Shorter and shorter lasers * Increasingly powerful lasers * Lasers: A Universal Tool? * Cutting, welding, and cleaning * Communicating * Treating illnesses * Measuring * Supplying energy? * Entertaining * Understanding * Conclusion

  11. Variables affecting clinical response to treatment of facial port-wine stains by flash lamp-pumped pulsed dye laser: the importance of looking beyond the skin.

    PubMed

    Bencini, Pier Luca; Cazzaniga, Simone; Galimberti, Michela Gianna; Zane, Cristina; Naldi, Luigi

    2014-07-01

    The response of port-wine stains (PWS) to conventional laser treatment in adults is difficult to predict. To assess the influence of local or systemic hemodynamic variables on the clearance of PWS by using flash lamp-pumped pulsed (FLPP) dye laser. All consecutive patients ages 18 years or older undergoing laser treatment for a facial PWS were eligible. Laser sessions were scheduled every 8 weeks. All patients were evaluated based on a standard scale with four evaluation categories, from no or minimal improvement to total or almost total clearance. Clearance was achieved by 50.1 % (95 % confidence interval 35.6-64.7) of patients after a maximum of 15 treatment sessions. In multivariate analysis, increased age, a newly described Type III capillaroscopic pattern, and presence of lesions in dermatome V2 were all associated with a reduced clinical response to treatment. In a model restricted to demographic pattern and patient characteristics, arterial hypertension was also associated with a lower clinical response. A strong association was found between arterial hypertension and the Type III capillaroscopic pattern. Age, arterial hypertension, capillaroscopic pattern, and body location should be considered when planning laser treatment of PWS.

  12. Intracavity dye laser spectroscopy studies of the Ba + N(2)O, Ca + N(2)O + CO, and Sr + N(2)O + CO reactions.

    PubMed

    Eckstrom, D J; Barker, J R; Hawley, J G; Reilly, J P

    1977-08-01

    A search for gain or absorption on several candidate visible chemical laser transitions has been carried out using the intracavity dye laser probe technique. Absorption was found on the following v'' ? v' bands of the BaO(A(1)Sigma ? X(1)Sigma) bands in the Ba + N(2)O reaction: 0 ? 1; 0 ? 4; 1 ? 1; 1 ? 2, and 5 ? 1. No gain or absorption could be detected on the 7 ? 1, 6 ? 0, and 4 ? 0 bands (sensitivity ~10(-4)/cm). In Ca, Sr + N(2)O + CO flames, absorption was found in the green arc bands of CaO and the red arc bands of SrO. Several new bandhead wavelengths are reported. Our results support assignment of the arc bands to the diatomic metal oxides. Absorptions and enhancements were found on various Sr, Ba, and Ba(+) transitions. PMID:20168881

  13. Transparent gel and xerogel of thorium phosphate: optical spectroscopy with: Nd3+,Eu3+,Cr3+ and Rhodamine 6G

    SciTech Connect

    Genet, M.; Brandel, V.; Lahalle, M.P.; Simoni, E.

    1992-03-01

    Chemical conditions for thorium phosphate gel preparation have been determined. The transparency is of good optical quality and the gel is very stable for a long time. Under drying condition, this gel can give rise to the xerogel which is still transparent. We can also prepare this xerogel by simple evaporation at room temperature of a very concentrated solution of thorium phosphate. From this viscous medium, the xerogel can be obtained in various kinds of shapes : threads, slabs and blocks. Solidification time depends on the final volume desired and spreads from few minutes to several weeks. Absorption spectrum of pure gel and xerogel have been recorded. Gel and xerogel doped with very well known probes like Nd3+ and Er3+ were examined to compare their optical properties with aqueous medium of the same chemical composition. Eu3+ doped gel and xerogel were also studied using their fluorescence properties. The optical properties of Cr3+ in doped gel and xerogel allowed us to determine the kinetics of hydration sphere modification during the drying period. Finally, as xerogel synthesis takes place at room temperature, fragile organic dye can be used as dopant, so Rhodamine 6G absorption and emission spectra have been studied in these conditions. When, at that time, the xerogel is doped with Coumarin 460 and Tb3+ an energy transfer is observed between dye and Tb3+ ions, which contributes to enhance the fluorescence of Tb3+ ions. Eu3+ behaves similarly. In conclusion, gel and xerogel of thorium phosphate tested with usual probes such as 3d, 4f ions and dyes seem to be very promising matrices.

  14. Direct patterning of rhodamine 6G molecules on mica by dip-pen nanolithography [rapid communication

    NASA Astrophysics Data System (ADS)

    Zhou, Hualan; Li, Zhuang; Wu, Aiguo; Wei, Gang; Liu, Zhiguo

    2004-09-01

    Dip-pen nanolithography (DPN) has been developed to pattern monolayer film of various molecules on suitable substrate through the controlled movement of ink-coated atomic force microscopy (AFM) tip, which makes DPN a potentially powerful tool for making the functional nanoscale devices. In this paper, the direct patterning of rhodamine 6G on mica by dip-pen nanolithography was demonstrated. R6G features patterned on the mica was successfully achieved with different tip movement which can be programmed by Nanoscript™ language. From the AFM image of R6G patterns, we know that R6G molecule is flatly binding to the mica surface through electrostatic interaction, thus stable R6G nanostructures could be formed on mica. The influence of translation speed and contact time on DPN was discussed. The method can be extended to direct patterning of many other organic molecules, and should open many opportunities for miniaturized optical device and site-specific biological staining.

  15. [Fluorescence Resonance Energy Transfer Detection of Cobalt Ions by Silver Triangular Nanoplates and Rhodamine 6G].

    PubMed

    Zhang, Xiu-qing; Peng, Jun; Ling, Jian; Liu, Chao-juan; Cao, Qiu-e; Ding, Zhong-tao

    2015-04-01

    In the present paper, the authors studied fluorescence resonance energy transfer (FRET) phenomenon between silver triangular nanoplates and bovine serum albumin (BSA)/Rhodamine 6G fluorescence complex, and established a fluorescence method for the detection of cobalt ions. We found that when increasing the silver triangular nanoplates added to certain concentrations of fluorescent bovine serum albumin (BSA)/Rhodamine 6G complex, the fluorescence of Rhodamine 6G would be quenched up to 80% due to the FRET between the quencher and donor. However, in the presence of cobalt ions, the disassociation of the fluorescent complex from silver triangular nanoplates occurred and the fluorescence of the Rhodamine 6G recovered. The recovery of fluorescence intensity rate (I/I0) has a good relationship with the cobalt ion concentration (cCO2+) added. Thus, the authors developed a fluorescence method for the detection of cobalt ions based on the FRET of silver triangular nanoplates and Rhodamine 6G.

  16. Rapid sintering of MoS2 counter electrode using near-infrared pulsed laser for use in highly efficient dye-sensitized solar cells

    NASA Astrophysics Data System (ADS)

    Jeong, Hansol; Kim, Jae-Yup; Koo, Bonkee; Son, Hae Jung; Kim, Dongwhan; Ko, Min Jae

    2016-10-01

    Molybdenum disulfide (MoS2) is a promising material for use as a low-cost electrocatalytic counter electrode (CE) in photoelectrochemical dye-sensitized solar cells (DSSCs). However, currently, the MoS2 CEs are generally prepared with a high temperature sintering for the synthesis and crystallization of MoS2. Here, we report a simple and rapid method for the preparation of highly efficient MoS2 CEs. The MoS2 films were synthesized at 70 °C, followed by sintering with a near-infrared (IR) pulsed laser for 1 min. Compared to the conventional heat-sintered MoS2 CE, the laser-sintered CE showed enhanced crystallinity and improved interconnection between the MoS2 particles, resulting in superior electrocatalytic activity towards the I-/I3- redox couple. When used in a DSSC, the laser-sintered MoS2 CE exhibited a higher conversion efficiency (η = 7.19%) compared to that of the heat-sintered CE (η = 5.96%). Furthermore, the laser-sintered CE had a comparable conversion efficiency compared to that of the conventional Pt CE (η = 7.42%).

  17. Relation between skin surface temperature and minimal blanching during argon, Nd-YAG 532, and CW dye 585 laser therapy of port-wine stains.

    PubMed

    Mordon, S; Beacco, C; Rotteleur, G; Brunetaud, J M

    1993-01-01

    Laser photocoagulation has proven to be valuable in the treatment of port-wine stains. In this application, the minimal blanching technique is used as an indicator of suitable dosage since it has been demonstrated that the immediate appearance a white mark is required to achieve permanent blanching a few months later. The objective of the investigations undertaken in this study was to correlate the temperature attained at the surface of port-wine stains with immediate blanching, upon irradiation with different laser fluences. A comparative study was performed using an argon laser (all lines), a 532 nm Nd:YAG and a 585 nm argon pumped dye laser. Surface temperature was studied using an infrared camera. Temperature was measured on 10 different port-wine stains using different fluences. Whitening threshold fluence was related to surface temperature. It appeared that whitening threshold fluence corresponded to a surface temperature of 53 degrees C (+/- 3 degrees C). The whitening threshold fluence was dependent on port-wine stains and wavelength. However, whitening threshold fluence remained lower for 532 nm and 585 nm and it correlated to the absorption curve of hemoglobin.

  18. Highly sensitive wavelength-dependent nonaqueous capillary electrophoresis for simultaneous screening of various synthetic organic dyes.

    PubMed

    Park, Moonhee; Bahng, Seung-Hoon; Woo, Nain; Kang, Seong Ho

    2016-05-15

    A novel multi-wavelength nonaqueous capillary electrophoresis (MW-NACE) technique based on wavelength-dependent laser-induced fluorescence (LIF) detection was investigated for the simultaneous screening of various synthetic organic dyes. Multi-wavelength excitation light sources were utilized to excite different organic dyes [e.g., 543 nm for crystal violet (CV), methyl violet B (MVB), methyl violet B base (MBB), rhodamine 6G (R6G), and rhodamine B base (RBB); 635 nm for nile blue A (NBA) and methylene blue (MB)] simultaneously. Using a nonaqueous buffer system composed of 15 mM sodium borate and 835 mM acetic acid in 100% ethanol (pH=5.4), all dyes were analyzed within 15 min with excellent resolution (R≥4.0) under an electric field of 500 V/cm. Calibration curves showed excellent linearity with square of correlation coefficients (r(2)) greater than 0.9908 over wide dynamic ranges of 0.4-50 μM for CV, 0.8-50 μM for MVB, 1.5-50 μM for MBB, 0.08-5 nM for R6G, 0.06-10 μM for MB, 0.02-10 μM for NBA, and 0.13-10 pM for RBB. The detection limits (S/N=3) of 40 fM to 0.5 μM were 10-200,000 times lower than those of previous detection methods. While adjacent peaks were not well distinguished with baseline separation in a single capillary, the devised technique was faster and more sensitive than conventional aqueous and nonaqueous CE approaches, thereby enabling the quantitative analysis of various dyes based on wavelength-dependent fluorescence detection with different excitation wavelengths. PMID:26992516

  19. Random laser action from flexible biocellulose-based device

    NASA Astrophysics Data System (ADS)

    dos Santos, Molíria V.; Dominguez, Christian T.; Schiavon, João V.; Barud, Hernane S.; de Melo, Luciana S. A.; Ribeiro, Sidney J. L.; Gomes, Anderson S. L.; de Araújo, Cid B.

    2014-02-01

    We demonstrate random lasing action in flexible bacterial cellulose (BC) membrane containing a laser-dye and either dielectric or metallic nanoparticles (NPs). The novel random laser system consists of BC nanofibers attached with Rhodamine 6G molecules and having incorporated either silica or silver NPs. The laser action was obtained by excitation of the samples with a 6 ns pulsed laser at 532 nm. Minimum laser threshold of ≈0.7 mJ/pulse was measured for the samples with silica NPs, whereas a laser threshold of 2.5 mJ/pulse for a system based on silver NPs was obtained. In both cases a linewidth narrowing from ≈50 to ≈4 nm was observed. Potential applications in biophotonics and life sciences are discussed for this proof-of-concept device.

  20. Dye Painting!

    ERIC Educational Resources Information Center

    Johnston, Ann

    This resource provides practical instructions for applying color and design directly to fabric. Basic information about the dye painting process is given. The guide addresses the technical aspects of fabric dye and color use and offers suggestions for fabric manipulation and dye application in order to achieve various design effects. This…

  1. Rhodamine-6G can photosensitize folic acid decomposition through electron transfer

    NASA Astrophysics Data System (ADS)

    Hirakawa, Kazutaka; Ito, Hiroki

    2015-05-01

    Rhodamine-6G photosensitized folic acid decomposition in aqueous solution, and its quantum yield in the presence of 10 μM folic acid was 9.9 × 10-6. A possible mechanism of this photodecomposition is direct oxidation through an electron transfer from folic acid to rhodamine-6G. The fluorescence lifetime of rhodamine-6G was slightly decreased by folic acid, suggesting electron transfer in the excited singlet state of rhodamine-6G. The quenching rate coefficient estimated from the Stern-Volmer plot of the fluorescence quenching supported that this electron transfer proceeds as a diffusion-controlled reaction. The quantum yields of the electron transfer and the following reaction could be determined.

  2. On a PLIF quantification methodology in a nonlinear dye response regime

    NASA Astrophysics Data System (ADS)

    Baj, P.; Bruce, P. J. K.; Buxton, O. R. H.

    2016-06-01

    A new technique of planar laser-induced fluorescence calibration is presented in this work. It accounts for a nonlinear dye response at high concentrations, an illumination light attenuation and a secondary fluorescence's influence in particular. An analytical approximation of a generic solution of the Beer-Lambert law is provided and utilized for effective concentration evaluation. These features make the technique particularly well suited for high concentration measurements, or those with a large range of concentration values, c, present (i.e. a high dynamic range of c). The method is applied to data gathered in a water flume experiment where a stream of a fluorescent dye (rhodamine 6G) was released into a grid-generated turbulent flow. Based on these results, it is shown that the illumination attenuation and the secondary fluorescence introduce a significant error into the data quantification (up to 15 and 80 %, respectively, for the case considered in this work) unless properly accounted for.

  3. Organic random lasers in the weak-scattering regime

    NASA Astrophysics Data System (ADS)

    Polson, R. C.; Vardeny, Z. V.

    2005-01-01

    We used the ensemble-averaged power Fourier transform (PFT) of random laser emission spectra over the illuminated area to study random lasers with coherent feedback in four different disordered organic gain media in the weak scattering regime, where the light mean free path, ℓ* is much larger than the emission wavelength. The disordered gain media include a π -conjugated polymer film, an opal photonic crystal infiltrated with a laser dye (rhodamine 6G; R6G) having optical gain in the visible spectral range, a suspension of titania balls in R6G solution, and biological tissues such as chicken breast infiltrated with R6G. We show the existence of universality among the random resonators in each gain medium that we tested, in which at the same excitation intensity a dominant random cavity is excited in different parts of the sample. We show a second universality when scaling the average PFT of the four different media by ℓ* ; we found that the dominant cavity in each disordered gain medium scales with ℓ* . The excellent agreement obtained with computer simulations using a distribution of random microdisks, each contributing a number of longitudinal whispering gallery modes within the gain spectrum, unambiguously shows that random lasers in the weak scattering regime cannot be described by gain amplification of localized photon states.

  4. Correlation of surface enhanced Raman spectroscopy and nanoparticle aggregation with rhodamine 6G

    NASA Astrophysics Data System (ADS)

    Hoff, Christopher A.

    Surface enhanced Raman spectroscopy (SERS) has fascinated the analytical chemistry field for decades. The SERS phenomenon has progressively leveraged the inherently insensitive Raman phenomenon from a novelty vibrational spectroscopy method into one capable of single molecule detection, with attendant molecular level selectivity and information. Yet, even after 40 years since its discovery, the core mechanism behind this phenomenon is still debated. This thesis presents results from a series of photometric titrations wherein solutions of 30 nm Au@Ag nanoparticles (NPs) were titrated with rhodamine 6G (R6G), spanning five orders of magnitude in R6G concentration, and which elucidate the conditions required for the onset of SERS by R6G in this system. The experiments illustrated the correlation between the Raman response and the plasmonic (via UV-Vis spectroscopy) properties of the nanoparticle solutions. It was found that the onset of R6G SERS was related much more closely to the aggregation of the nanoparticles in solution than to their R6G adsorbed surface coverage. However, triggering aggregation with sodium chloride appeared to enhance SERS by an independent mechanism, which is operative only at low, i.e., [NaCl] > 100 mM concentration.

  5. Stark spectroscopy of a probe lithium beam excited with two dye lasers as a technique to study a high-power ion-beam diode

    SciTech Connect

    Knyazev, B. A.; An, W.; Bluhm, H.

    2012-03-15

    A non-disturbing measurement of electric field distributions is a subject of special interest in plasma physics and high-voltage devices. In this paper we describe a diagnostic technique for remote sensing of electric fields via injection of a probe beam of lithium atoms and cascade excitation of resonance fluorescence with two broadband dye lasers. The fluorescence spectrum was recorded using a monochromator equipped with an optical multi-channel analyser. The magnitude of the local electric field was retrieved from the Stark-shifted components of the 3d-2plithium spectral line. The technique was applied to measurements of the electric field in the applied-B-field high-voltage diode of the 1 TW KALIF ion-beam accelerator.

  6. Stark spectroscopy of a probe lithium beam excited with two dye lasers as a technique to study a high-power ion-beam diode.

    PubMed

    Knyazev, B A; An, W; Bluhm, H

    2012-03-01

    A non-disturbing measurement of electric field distributions is a subject of special interest in plasma physics and high-voltage devices. In this paper we describe a diagnostic technique for remote sensing of electric fields via injection of a probe beam of lithium atoms and cascade excitation of resonance fluorescence with two broadband dye lasers. The fluorescence spectrum was recorded using a monochromator equipped with an optical multi-channel analyser. The magnitude of the local electric field was retrieved from the Stark-shifted components of the 3d-2p lithium spectral line. The technique was applied to measurements of the electric field in the applied-B-field high-voltage diode of the 1 TW KALIF ion-beam accelerator. PMID:22462900

  7. Studies of the photophysics of highly fluorescent Red Mega 480 laser dye in solutions: Steady state spectroscopy.

    PubMed

    Tangod, V B; Mastiholi, B M; Raikar, Prasad; Kulkarni, S G; Raikar, U S

    2015-09-01

    The absorption and fluorescence spectra of highly fluorescent industrially useful medium sized Red Mega 480 dye have been studied in various solvents at 298 K. The solute photophysical behavior depends strongly on the solute-solvent interactions. In order to understand the effect of inter molecular interactions on spectral behaviors of the dye in different solvents extent of this behavior can be analyzed by linear solvation energy relationships. In addition, ground and excited state dipole moments were evaluated by various methods. It is observed that excited state dipole moment (μe) is larger than the ground state (μg), absorption spectra show a bathochromic shift with increasing polarity indicating that transition involved is π→π(∗) and Onsager cavity radius is determined by atomic increment method.

  8. Assessment of the C-525 laser dye as a chemiluminescence sensitizer for lipid peroxidation in biological membranes: a comparison with chlorophyll-a.

    PubMed

    Sharov, V S; Briviba, K; Sies, H

    1996-01-01

    The C-525 laser dye at micromolar concentration range is shown to enhance up to two to three orders of magnitude the chemiluminescence (CL) accompanying tert-butyl hydroperoxide (t-BHP)-induced rat liver microsome oxidation and Fe(2+)-induced lipid peroxidation (LPO) in liposomes. C-525 is shown to be a more efficient sensitizer of CL accompanying LPO in membrane systems than the known low-energy excited triplet carbonyl sensitizer, chlorophyll-alpha, (Cl-a). Regarding the sensitization mechanism, C-525 and Cl-a were compared in (a) a peroxyl radical-producing system (2,2'-azobis(2-dimethylvaleronitrile) (AMVN); (b) excited carbonyl-producing systems (3-hydroxymethyl-3,4,4-trimethyl-1,2-dioxetane (HTMD) thermal decomposition and horseradish peroxidase (HRP)-catalyzed isobutanal oxidation); and (c) excited singlet oxygen-producing system [endoperoxide of 3,3-(1,4-naphthylidene)-dipropionate (NDPO2)]. C-525 sensitized CL only in the systems where peroxyl radical and/or triplet excited carbonyls are produced, the mechanism of CL sensitization apparently is energy transfer from the excited triplet carbonyls formed in the peroxyl radical self-reaction via Russell's mechanism or by dioxetane decomposition. Cl-a was found to considerably sensitize CL related to NDPO2 thermal decomposition, a source of singlet oxygen, in addition to acting as a sensitizer of triplet carbonyl CL. The chemical stability of the C-525 laser dye in excited state-generating systems was shown to be appropriate for its application as a sensitizer of CL related to LPO reactions in membranes, but not in the HRP-catalyzed peroxidation system. PMID:8902529

  9. Computational study of Gleevec and G6G reveals molecular determinants of kinase inhibitor selectivity

    SciTech Connect

    Lin, Yen -Lin; Meng, Yilin; Huang, Lei; Roux, Benoît

    2014-10-22

    Gleevec is a potent inhibitor of Abl tyrosine kinase but not of the highly homologous c-Src kinase. Because the ligand binds to an inactive form of the protein in which an Asp-Phe-Gly structural motif along the activation loop adopts a so-called DFG-out conformation, it was suggested that binding specificity was controlled by a “conformational selection” mechanism. In this context, the binding affinity displayed by the kinase inhibitor G6G poses an intriguing challenge. Although it possesses a chemical core very similar to that of Gleevec, G6G is a potent inhibitor of both Abl and c-Src kinases. Both inhibitors bind to the DFG-out conformation of the kinases, which seems to be in contradiction with the conformational selection mechanism. To address this issue and display the hidden thermodynamic contributions affecting the binding selectivity, molecular dynamics free energy simulations with explicit solvent molecules were carried out. Relative to Gleevec, G6G forms highly favorable van der Waals dispersive interactions upon binding to the kinases via its triazine functional group, which is considerably larger than the corresponding pyridine moiety in Gleevec. Upon binding of G6G to c-Src, these interactions offset the unfavorable free energy cost of the DFG-out conformation. When binding to Abl, however, G6G experiences an unfavorable free energy penalty due to steric clashes with the phosphate-binding loop, yielding an overall binding affinity that is similar to that of Gleevec. Such steric clashes are absent when G6G binds to c-Src, due to the extended conformation of the phosphate-binding loop.

  10. Computational study of Gleevec and G6G reveals molecular determinants of kinase inhibitor selectivity

    DOE PAGES

    Lin, Yen -Lin; Meng, Yilin; Huang, Lei; Roux, Benoît

    2014-10-22

    Gleevec is a potent inhibitor of Abl tyrosine kinase but not of the highly homologous c-Src kinase. Because the ligand binds to an inactive form of the protein in which an Asp-Phe-Gly structural motif along the activation loop adopts a so-called DFG-out conformation, it was suggested that binding specificity was controlled by a “conformational selection” mechanism. In this context, the binding affinity displayed by the kinase inhibitor G6G poses an intriguing challenge. Although it possesses a chemical core very similar to that of Gleevec, G6G is a potent inhibitor of both Abl and c-Src kinases. Both inhibitors bind to themore » DFG-out conformation of the kinases, which seems to be in contradiction with the conformational selection mechanism. To address this issue and display the hidden thermodynamic contributions affecting the binding selectivity, molecular dynamics free energy simulations with explicit solvent molecules were carried out. Relative to Gleevec, G6G forms highly favorable van der Waals dispersive interactions upon binding to the kinases via its triazine functional group, which is considerably larger than the corresponding pyridine moiety in Gleevec. Upon binding of G6G to c-Src, these interactions offset the unfavorable free energy cost of the DFG-out conformation. When binding to Abl, however, G6G experiences an unfavorable free energy penalty due to steric clashes with the phosphate-binding loop, yielding an overall binding affinity that is similar to that of Gleevec. Such steric clashes are absent when G6G binds to c-Src, due to the extended conformation of the phosphate-binding loop.« less

  11. Pulsed dye laser fragmentation of ureteral calculi: a review of the first 50 cases performed at Virginia Mason Medical Center.

    PubMed

    Govier, F E; Gibbons, R P; Correa, R J; Brannen, G E; Weissman, R M; Pritchett, T R

    1990-04-01

    During the preceding 2 1/2 years 50 patients have undergone laser fragmentation of ureteral calculi at our medical center. Of these 50 patients 48 (96%) became free of stones without the need for an open operation: 44 (88%) were managed in 1 setting and 4 required adjunctive extracorporeal shock wave or ultrasonic lithotripsy, or a repeat session with the laser. Two patients (4%) eventually required an open operation: 1 required ureterolithotomy for a large impacted stone overlying the bony pelvis after a ureteroscope could not be advanced to this level and 1 had a good initial result with the laser but a persistent ureteral stricture developed and he required ureteroureterostomy 4 months later. Both open procedures were necessitated by mid ureteral stones, and the ureteral stricture was believed to be related to ureteroscopy and the impacted nature of the stone, rather than any damage by the laser probe.

  12. Rotational and Translational Dynamics of Rhodamine 6G in a Pyrrolidinium Ionic Liquid: A Combined Time-Resolved Fluorescence Anisotropy Decay and NMR Study

    SciTech Connect

    Guo, Jianchang; Han, Kee Sung; Mahurin, Shannon Mark; Baker, Gary A; Hillesheim, Patrick C; Dai, Sheng; Hagaman, Edward {Ed} W; Shaw, Robert W

    2012-01-01

    NMR spectroscopy and time-resolved fluorescence anisotropy decay (TRFAD) are two of the most commonly used methods to study solute-solvent interactions. However, only a few studies have been reported to date using a combined NMR and TRFAD approach to systematically investigate the overall picture of diffusional and rotational dynamics of both the solute and solvent. In this paper, we combined NMR and TRFAD to probe fluorescent rhodamine dyes in a pyrrolidinium-based room temperature ionic liquid (RTIL), an emergent environmentally-friendly solvent type used in several energy-related applications. A specific interaction of the R6G cation and [Tf2N]- anion was identified, resulting in near-stick boundary condition rotation of R6G in this RTIL. The diffusional rates of the R6G solute and [C4mpyr][Tf2N] solvent derived from 1H NMR suggest the rates are proportional to their corresponding hydrodynamic radii. The 1H and 13C NMR studies of self-rotational dynamics of [C4mpyr][Tf2N] showed that the self-rotational correlation time of [C4mpyr]+ is 47 2 ps at 300 K. At the same temperature, we find that the correlation time for N-CH3 rotation in [C4mpyr]+ is 77 2 ps, comparable to overall molecular reorientation. This slow motion is attributed to properties of the cation structure.

  13. Homogeneous linewidths of Rhodamine 6G at room temperature from cavity-enhanced spontaneous emission rates

    SciTech Connect

    Barnes, M.D.; Whitten, W.B.; Arnold, S.; Ramsey, J.M. )

    1992-11-15

    Fluorescence lifetimes of Rhodamine 6G in levitated micron-sized droplets have been measured using a time-correlated photon counting technique. The coupling of emission into spherical cavity modes of the droplet results in significant emission rate enhancements which allow estimation of the homogeneous linewidth at room temperature.

  14. Resonance Raman Scattering of Rhodamine 6G as Calculated Using Time-Dependent Density Functional Theory

    SciTech Connect

    Jensen, Lasse; Schatz, George C.

    2006-03-27

    The research described in this product was performed in part in the Environmental Molecular Sciences Laboratory, a national scientific user facility sponsored by the Department of Energy's Office of Biological and Environmental Research and located at Pacific Northwest National Laboratory. In this work, we present the first calculation of the resonance Raman scattering (RRS) spectrum of rhodamine 6G (R6G) which is a prototype molecule in surface-enhanced Raman scattering (SERS). The calculation is done using a recently developed time-dependent density functional theory (TDDFT) method, which uses a short-time approximation to evaluate the Raman scattering cross section. The normal Raman spectrum calculated with this method is in good agreement with experimental results. The calculated RRS spectrum shows qualitative agreement with SERS results at a wavelength that corresponds to excitation of the S1 state, but there are significant differences with the measured RRS spectrum at wavelengths that correspond to excitation of the vibronic sideband of S1. Although the agreement with the experiments is not perfect, the results provide insight into the RRS spectrum of R6G at wavelengths close to the absorption maximum where experiments are hindered due to strong fluorescence. The calculated resonance enhancements are found to be on the order of 105. This indicates that a surface enhancement factor of about 1010 would be required in SERS in order to achieve single-molecule detection of R6G.

  15. Treatment of Acne Vulgaris With Salicylic Acid Chemical Peel and Pulsed Dye Laser: A Split Face, Rater-Blinded, Randomized Controlled Trial

    PubMed Central

    Lekakh, Olga; Mahoney, Anne Marie; Novice, Karlee; Kamalpour, Julia; Sadeghian, Azeen; Mondo, Dana; Kalnicky, Cathy; Guo, Rong; Peterson, Anthony; Tung, Rebecca

    2015-01-01

    Introduction: Pulsed dye laser (PDL) has been used to treat acne lesions and scar erythema by interrupting superficial vasculature. Salicylic acid chemical peels are employed chiefly due to their lipophilic, comedolytic, and anti-inflammatory properties. Although studies have looked at peels and laser therapy independently in acne management, we examined these treatments in combination. Our primary objective was to evaluate the safety and efficacy of concurrent use of salicylic acid peels with PDL versus salicylic acid peels alone in the treatment of moderate to severe acne vulgaris. Methods: Adult patients with moderate to severe acne were included. Subjects received a total of 3 treatments at 3-week intervals. Per randomized split-face treatment, at week 0, one half of the subject’s face was treated with PDL (595 nm) followed by whole face application of a 30% salicylic acid peel. At weeks 3 and 6, the treatments were repeated. At 0 and 9 weeks, patients were assessed with the Global Evaluation Acne (GEA) scale and Dermatology Life Quality Index (DLQI) questionnaire. Results: Nineteen subjects were enrolled, and 18 completed the study. Significant improvement in acne was seen in both the combined (laser and peel) and chemical peel alone treatment arms (P < .0005 and P = .001). Using the GEA scale score, compared to week 0, the mean difference in acne improvement at week 9 was -1.61 in the combination therapy group versus -1.11 in the peel only group. Based on the GEA scale scoring, a statistically significant greater difference in acne improvement was seen, from week 0 to week 9, in the combination treatment group compared with the peel only group (P = .003). Conclusion: While acne subjects had significant benefit from the salicylic acid peel alone, they experienced greater significant benefit from PDL treatment used in conjunction with salicylic acid peels. The adjunctive utilization of PDL to salicylic acid peel therapy can lead to better outcomes in acne

  16. Computer-aided design and modeling of nickel dithiolene near-infrared dyes. 1998 summer research program for high school juniors at the University of Rochester`s Laboratory for Laser Energetics: Student research reports

    SciTech Connect

    Corsello, S.

    1999-03-01

    Recent advances in computational chemistry have made it feasible to design many types of molecules and predict their properties theoretically. The author applied these techniques to the design of organometallic transition-metal dyes absorbing in the near-infrared region of the spectrum which possess the combination of a large molar extinction coefficient, good chemical and thermal stability, and a high solubility in liquid crystal (LC) hosts. These properties are required for the dye to function as a near-infrared (IR) attenuator in a liquid crystal point diffraction interferometer (LCPDI) device that will be used as a beam diagnostic on the 60-beam OMEGA solid-state Nd:glass laser system at the University of Rochester`s Laboratory for Laser Energetics. Using commercially available software, both the absorption spectra and solubility characteristics of bis[1,2-di-(p-n alkoxyphenyl)ethane-1,2-dithione] nickel dye complexes were modeled in an isotropic host (cyclohexane) and, in most cases, excellent agreement was found with experimental data. Two additional compounds utilizing the same nickel dithiolene core but with alkylthio and phenylalkylthio terminal groups have been designed and show excellent potential to produce dramatic improvements in both solubility and optical density (absorbance) in liquid crystalline hosts. Based upon my work, a new dye not previously reported, 2(C{sub 4}S)2(C{sub 4}SPh)DTNi, has been proposed to satisfy the LCPDI device requirements. The nickel dithiolene dyes may also find important applications in other technology areas such as near-IR photography and laser-based near-IR communications.

  17. Prospective Comparison of Dual Wavelength Long-Pulsed 755-nm Alexandrite/1,064-nm Neodymium:Yttrium-Aluminum-Garnet Laser versus 585-nm Pulsed Dye Laser Treatment for Rosacea

    PubMed Central

    Seo, Hyun-Min; Kim, Jung-In; Kim, Han-Saem; Choi, Young-Jun

    2016-01-01

    Background Rosacea treatments including oral/topical medications and laser therapy are numerous but unsatisfactory. Objective To compare the effectiveness of the dual wavelength long-pulsed 755-nm alexandrite/1,064-nm neodymium: yttrium-aluminum-garnet laser (LPAN) with that of 585-nm pulsed dye laser (PDL) for rosacea. Methods This was a randomized, single-blinded, comparative study. Full face received four consecutive monthly treatments with LPAN or PDL, followed-up for 6 months after the last treatment. Erythema index was measured by spectrophotometer, and digital photographs were evaluated by consultant dermatologists for physician's global assessment. Subjective satisfaction surveys and adverse effects were recorded. Results Forty-nine subjects with rosacea enrolled and 12 dropped out. There were no significant differences between LPAN and PDL in the mean reduction of the erythema index (p=0.812; 3.6% vs. 2.8%), improvement of physician's global assessment (p=1.000; 88.9% vs. 89.5%), and subject-rated treatment satisfaction (p=0.842; 77.8% vs. 84.2%). PDL showed more adverse effects including vesicles than LPAN (p=0.046; 26.3% vs. 0.0%). No other serious or permanent adverse events were observed in both treatments. Conclusion Both LPAN and PDL may be effective and safe treatments for rosacea. PMID:27746641

  18. Fluorescent Ly6G antibodies determine macrophage phagocytosis of neutrophils and alter the retrieval of neutrophils in mice.

    PubMed

    Bucher, Kirsten; Schmitt, Fee; Autenrieth, Stella E; Dillmann, Inken; Nürnberg, Bernd; Schenke-Layland, Katja; Beer-Hammer, Sandra

    2015-09-01

    Fluorescently labeled Ly6G antibodies enable the tracking of neutrophils in mice, whereas purified anti-Ly6G rapidly depletes neutrophils from the circulation. The mechanisms underlying neutrophil depletion are still under debate. Here, we examined how identical Ly6G antibodies coupled to different fluorochromes affect neutrophil fate in vivo. BM cells stained with Ly6G antibodies were injected into mice. The number of retrieved anti-Ly6G-FITC(+) cells was reduced significantly in comparison with anti-Ly6G-APC(+) or anti-Ly6G-PE(+) cells. Flow cytometry and multispectral imaging flow cytometry analyses revealed that anti-Ly6G-FITC(+) neutrophils were preferentially phagocytosed by BMMs in vitro and by splenic, hepatic, and BM macrophages in vivo. Direct antibody injection of anti-Ly6G-FITC but not anti-Ly6G-PE depleted neutrophils to the same degree as purified anti-Ly6G, indicating that the FITC-coupled antibody eliminates neutrophils by a similar mechanism as the uncoupled antibody. With the use of a protein G-binding assay, we demonstrated that APC and PE but not FITC coupling inhibited access to interaction sites on the anti-Ly6G antibody. We conclude the following: 1) that neutrophil phagocytosis by macrophages is a central mechanism in anti-Ly6G-induced neutrophil depletion and 2) that fluorochrome-coupling can affect functional properties of anti-Ly6G antibodies, thereby modifying macrophage uptake of Ly6G-labeled neutrophils and neutrophil retrieval following adoptive cell transfer or injection of fluorescent anti-Ly6G.

  19. Fluorescent Ly6G antibodies determine macrophage phagocytosis of neutrophils and alter the retrieval of neutrophils in mice.

    PubMed

    Bucher, Kirsten; Schmitt, Fee; Autenrieth, Stella E; Dillmann, Inken; Nürnberg, Bernd; Schenke-Layland, Katja; Beer-Hammer, Sandra

    2015-09-01

    Fluorescently labeled Ly6G antibodies enable the tracking of neutrophils in mice, whereas purified anti-Ly6G rapidly depletes neutrophils from the circulation. The mechanisms underlying neutrophil depletion are still under debate. Here, we examined how identical Ly6G antibodies coupled to different fluorochromes affect neutrophil fate in vivo. BM cells stained with Ly6G antibodies were injected into mice. The number of retrieved anti-Ly6G-FITC(+) cells was reduced significantly in comparison with anti-Ly6G-APC(+) or anti-Ly6G-PE(+) cells. Flow cytometry and multispectral imaging flow cytometry analyses revealed that anti-Ly6G-FITC(+) neutrophils were preferentially phagocytosed by BMMs in vitro and by splenic, hepatic, and BM macrophages in vivo. Direct antibody injection of anti-Ly6G-FITC but not anti-Ly6G-PE depleted neutrophils to the same degree as purified anti-Ly6G, indicating that the FITC-coupled antibody eliminates neutrophils by a similar mechanism as the uncoupled antibody. With the use of a protein G-binding assay, we demonstrated that APC and PE but not FITC coupling inhibited access to interaction sites on the anti-Ly6G antibody. We conclude the following: 1) that neutrophil phagocytosis by macrophages is a central mechanism in anti-Ly6G-induced neutrophil depletion and 2) that fluorochrome-coupling can affect functional properties of anti-Ly6G antibodies, thereby modifying macrophage uptake of Ly6G-labeled neutrophils and neutrophil retrieval following adoptive cell transfer or injection of fluorescent anti-Ly6G. PMID:26019296

  20. Acne vulgaris in the context of complex medical co-morbities: the management of severe acne vulgaris in a female with retinitis pigmentosa - utilizing pulse dye laser in conjunction with medical therapy.

    PubMed

    Shariff, Ayesha; Keck, Laura; Zlotoff, Barrett

    2014-03-17

    Acne vulgaris is a pervasive inflammatory disorder of the skin, with multiple etiologies and treatment options. Although first-line therapies exist, it is often the case that a patient will present with an underlying disorder that prohibits the use of most currently accepted treatment modalities. We present a patient with severe acne vulgaris and a history of retinitis pigmentosa who was treated with 595 nanometer pulsed dye laser therapy, in conjunction with therapeutic alternatives to first-line acne medications. Our patient exhibited a significant and sustained improvement with the combined use of 595 nanometer pulsed dye laser, Yaz (drospirenone-ethinyl estradiol), dapsone, topical metronidazole, sodium-sulfacetamide wash, and topical azelaic acid. The positive results in this case, suggest that this combined treatment modality may serve as an example of a safe and effective treatment alternative in the management of acne vulgaris complicated by medical co-morbidities that contraindicate the use of most first-line treatment options.

  1. Laser resonance ionization scheme development for tellurium and germanium at the dual Ti:Sa-Dye ISOLDE RILIS

    NASA Astrophysics Data System (ADS)

    Day Goodacre, T.; Fedorov, D.; Fedosseev, V. N.; Forster, L.; Marsh, B. A.; Rossel, R. E.; Rothe, S.; Veinhard, M.

    2016-09-01

    The resonance ionization laser ion source (RILIS) is the principal ion source of the ISOLDE radioactive beam facility based at CERN. Using the method of in-source laser resonance ionization spectroscopy, a transition to a new autoionizing state of tellurium was discovered and applied as part of a three-step, three-resonance, photo-ionization scheme. In a second study, a three-step, two-resonance, photo-ionization scheme for germanium was developed and the ionization efficiency was measured at ISOLDE. This work increases the range of ISOLDE RILIS ionized beams to 31 elements. Details of the spectroscopy studies are described and the new ionization schemes are summarized.

  2. [Fluorescence Determination of Trace Se with the Hydride-K13-Rhodamine 6G System].

    PubMed

    Liang, Ai-hui; Li, Yuan; Huang, Shan-shan; Luo, Yang-he; Wen, Gui-qing; Jiang, Zhi-liang

    2015-05-01

    Se is a necessary trace element for human and animals, but the excess intake of Se caused poison. Thus, it is very important to determination of Se in foods and water. The target of this study is development of a new, sensitive and selective hydride generation-molecular fluorescence method for the determination of Se. In 0. 36 mol . L-1 sulfuric acid, NaBH4 as reducing agent, Se (IV) is reduced to H2 Se. Usin3-g I solution as absorption liquid3, I- is reduced to I- by H2Se. When adding rhodamine 6G, Rhodamine 6G and I3- form association particles, which lead to the fluorescence intensity decreased. When Se(IV) existing, Rhodamine 6G and I3- bind less, And the remaining amount of Rhodamine 6G increase. So the fluorescence intensity is enhanced. The analytical conditions were optimized, a 0. 36 ml . L-1 H2SO4, 21. 6.g . L-1 NaBH4, 23.3 µm . L-1 rhodamine 6G, and 50 µmol . L-1 KI3 were chosen for use. When the excitation wavelength is at 480nm, the Rayleigh scattering peak does not affect the fluorescence recording, and was selected for determination of Se. Under the selected conditions, Se(IV) concentration in the 0. 02~0. 60 µg . mL-1 range and the increase value of the fluorescence intensity (ΔF) at 562 nm linear relationship. The linear regression equation is ΔF562 nm =12. 6c + 20. 9. The detecton limit was 0.01 µ.g . L-1. The influence of coexistence substances on the hydride generatin-molecular fluorescence determination of 5. 07 X10(-6) mol . L-1 Se(IV) was considered in details. Results showed that this new fluorescence method is of high selectivity, that is, 0. 5 mmol. L-1 Ba2+, Ca2+, Zn2+ and Fe3+, 0. 25 mmol . L-1 . Mg2+, 0. 05 mmol . L-1 K+, 0. 2 mmol . L-1 Al3+, 0. 025 mmol . L-1 Te(VI) do not interfere with the determination. The influence of Hg2+, CD2+ and Cu2+ that precipitate with Se(IV), can be eliminated by addition of complex reagent. This hydride generation-molecular fluorescence method has been applied to determination of trace Se in water

  3. Effects of bandwidth-limiting tuning elements in synchronously pumped mode-locked lasers

    SciTech Connect

    Zandi, B.; Casperson, L.W.; MacFarlane, D.L. )

    1990-03-01

    A description of bandwidth-limiting tuning filters is introduced into a semiclassical model for synchronously pumped mode-locked dye lasers. The finite phase memory of the molecular wave functions is included as are the isotropic molecular distribution and the finite vibrational relaxation times. The new set of equations has been solved numerically using the best available values for the various parameters. The results have been compared with experimental data obtained using a rhodamine 6G dye laser, which is synchronously pumped using an acousto-optically mode-locked argon laser. Tuning element effects have been studied using two- and three-plate birefringent filters and a tuning wedge, and the experimental results agree with the numerical solutions.

  4. Selectable Ultrasensitive Detection of Hg2+ with Rhodamine 6G-Modified Nanoporous Gold Optical Sensor

    PubMed Central

    Wang, Zheng; Yang, Min; Chen, Chao; Zhang, Ling; Zeng, Heping

    2016-01-01

    An extremely sensitive fluorescence sensor has been developed for selectively detection of mercury ions based on metallophilic Hg2+-Au+ interactions, which results in an effective release of pre-adsorbed rhodamine 6G (R6G) molecules from the nanoporous gold substrate, associated with a significant decrease of fluorescence intensity. The optical sensor has a detection sensitivity down to 0.6 pM for Hg2+ and CH3Hg+ ions, in particular a superior selectivity in a complex aqueous system containing 13 different types of metal ions, meanwhile maintaining a long-term stability after 10 cycles. Such a fluorescence sensor combining multiple advantages therefore present promising potentials in various applications. PMID:27403721

  5. Selectable Ultrasensitive Detection of Hg2+ with Rhodamine 6G-Modified Nanoporous Gold Optical Sensor

    NASA Astrophysics Data System (ADS)

    Wang, Zheng; Yang, Min; Chen, Chao; Zhang, Ling; Zeng, Heping

    2016-07-01

    An extremely sensitive fluorescence sensor has been developed for selectively detection of mercury ions based on metallophilic Hg2+-Au+ interactions, which results in an effective release of pre-adsorbed rhodamine 6G (R6G) molecules from the nanoporous gold substrate, associated with a significant decrease of fluorescence intensity. The optical sensor has a detection sensitivity down to 0.6 pM for Hg2+ and CH3Hg+ ions, in particular a superior selectivity in a complex aqueous system containing 13 different types of metal ions, meanwhile maintaining a long-term stability after 10 cycles. Such a fluorescence sensor combining multiple advantages therefore present promising potentials in various applications.

  6. Selectable Ultrasensitive Detection of Hg(2+) with Rhodamine 6G-Modified Nanoporous Gold Optical Sensor.

    PubMed

    Wang, Zheng; Yang, Min; Chen, Chao; Zhang, Ling; Zeng, Heping

    2016-01-01

    An extremely sensitive fluorescence sensor has been developed for selectively detection of mercury ions based on metallophilic Hg(2+)-Au(+) interactions, which results in an effective release of pre-adsorbed rhodamine 6G (R6G) molecules from the nanoporous gold substrate, associated with a significant decrease of fluorescence intensity. The optical sensor has a detection sensitivity down to 0.6 pM for Hg(2+) and CH3Hg(+) ions, in particular a superior selectivity in a complex aqueous system containing 13 different types of metal ions, meanwhile maintaining a long-term stability after 10 cycles. Such a fluorescence sensor combining multiple advantages therefore present promising potentials in various applications. PMID:27403721

  7. An assessment of the ICE6G_C(VM5a) glacial isostatic adjustment model

    NASA Astrophysics Data System (ADS)

    Purcell, A.; Tregoning, P.; Dehecq, A.

    2016-05-01

    The recent release of the next-generation global ice history model, ICE6G_C(VM5a), is likely to be of interest to a wide range of disciplines including oceanography (sea level studies), space gravity (mass balance studies), glaciology, and, of course, geodynamics (Earth rheology studies). In this paper we make an assessment of some aspects of the ICE6G_C(VM5a) model and show that the published present-day radial uplift rates are too high along the eastern side of the Antarctic Peninsula (by ˜8.6 mm/yr) and beneath the Ross Ice Shelf (by ˜5 mm/yr). Furthermore, the published spherical harmonic coefficients—which are meant to represent the dimensionless present-day changes due to glacial isostatic adjustment (GIA)—contain excessive power for degree ≥90, do not agree with physical expectations and do not represent accurately the ICE6G_C(VM5a) model. We show that the excessive power in the high-degree terms produces erroneous uplift rates when the empirical relationship of Purcell et al. (2011) is applied, but when correct Stokes coefficients are used, the empirical relationship produces excellent agreement with the fully rigorous computation of the radial velocity field, subject to the caveats first noted by Purcell et al. (2011). Using the Australian National University (ANU) groups CALSEA software package, we recompute the present-day GIA signal for the ice thickness history and Earth rheology used by Peltier et al. (2015) and provide dimensionless Stokes coefficients that can be used to correct satellite altimetry observations for GIA over oceans and by the space gravity community to separate GIA and present-day mass balance change signals. We denote the new data sets as ICE6G_ANU.

  8. Evaluating Heat Pipe Performance in 1/6 g Acceleration: Problems and Prospects

    NASA Technical Reports Server (NTRS)

    Jaworske, Donald A.; McCollum, Timothy A.; Gibson, Marc A.; Sanzi, James L.; Sechkar, Edward A.

    2011-01-01

    Heat pipes composed of titanium and water are being considered for use in the heat rejection system of a fission power system option for lunar exploration. Placed vertically on the lunar surface, the heat pipes would operate as thermosyphons in the 1/6 g environment. The design of thermosyphons for such an application is determined, in part, by the flooding limit. Flooding is composed of two components, the thickness of the fluid film on the walls of the thermosyphon and the interaction of the fluid flow with the concurrent vapor counter flow. Both the fluid thickness contribution and interfacial shear contribution are inversely proportional to gravity. Hence, evaluating the performance of a thermosyphon in a 1 g environment on Earth may inadvertently lead to overestimating the performance of the same thermosyphon as experienced in the 1/6 g environment on the moon. Several concepts of varying complexity have been proposed for evaluating thermosyphon performance in reduced gravity, ranging from tilting the thermosyphons on Earth based on a cosine function, to flying heat pipes on a low-g aircraft. This paper summarizes the problems and prospects for evaluating thermosyphon performance in 1/6 g.

  9. Lasers.

    ERIC Educational Resources Information Center

    Schewe, Phillip F.

    1981-01-01

    Examines the nature of laser light. Topics include: (1) production and characteristics of laser light; (2) nine types of lasers; (3) five laser techniques including holography; (4) laser spectroscopy; and (5) laser fusion and other applications. (SK)

  10. Dye Painting with Fiber Reactive Dyes

    ERIC Educational Resources Information Center

    Benjamin-Murray, Betsy

    1977-01-01

    In her description of how to use dyes directly onto fabrics the author lists materials to be used, directions for mixing dyes, techniques for applying dyes, references for additional reading and sources for dye materials. Preceding the activity with several lessons in design and other textile techniques with the dye process will ensure a…

  11. Sol-gel/rhodamine 6G composite films with tailored microstructures

    SciTech Connect

    Logan, D.L.; Ashley, C.S.; Assink, R.A.; Brinker, C.J. |

    1992-12-31

    A multi-step hydrolysis procedure was developed to prepare composite organic dye/sol-gel thin films with variable porosity for such as switches or sensors. Variation of acid and base catalyzed hydrolysis sequences of three sols prepared from tetraethoxysilane with identical H{sub 2}O/Si ratios, dilution factors, and pH resulted in considerably different silicate speciation. Under conditions where monomer was avoided, the refractive indices of as-deposited films could be varied by an again step prior to film deposition. This general strategy, which relies on the aggregation of fractal polymeric clusters, is compatible with the low temperature and near neutral pH requirements of both organic dyes and biologically active species such as enzymes.

  12. Anti-CD155 and anti-CD112 monoclonal antibodies conjugated to a fluorescent mesoporous silica nanosensor encapsulating rhodamine 6G and fluorescein for sensitive detection of liver cancer cells.

    PubMed

    Tao, Liang; Song, Chaojun; Huo, Chenyang; Sun, Yuanjie; Zhang, Chunmei; Li, Xiaohua; Yu, Shaojuan; Sun, Mingyu; Jin, Boquan; Zhang, Zhujun; Yang, Kun

    2016-08-01

    A novel method for sensitive detection of liver cancer cells using anti-CD155 and anti-CD112 monoclonal antibodies conjugated to ultrabright fluorescent mesoporous silica nanoparticles (FMSNs) encapsulating Rhodamine 6G and fluorescein was developed. The diameter of the obtained nanoparticles was 90 nm, and the quantum yield was 69%. Because the emission of fluorescein has a high degree of overlap with the excitation of Rhodamine 6G, and these two dyes were sufficiently close to each other on the nanoparticles, fluorescence resonance energy transfer can occur between these two dyes. This transfer not only maintains the original feature of the nanochannels and the skeletal network of the silica weakening the inner filtering of the dye, but also makes the excitation peak of the nanoparticles wider and increases the useful load amount of the dye. Because the wider Stokes shifts weaken the interference of excitation, the detection sensitivity is enhanced at the same time. The NaIO4 oxidation method does not use a cross-linker but rather uses covalent immobilization of the monoclonal antibodies on the FMSNs. This method can maintain the activity of the monoclonal antibodies more easily than the glutaraldehyde method. These advantages ensure that the nanosensor has high sensitivity and specificity for detecting liver cancer SMMC-7721 and HHCC cells. The in vivo imaging experiment also ensured that the biosensor can target tumor tissue in mice. PMID:27301350

  13. Holographic volume gratings in dye-doped jelly-like gelatin

    NASA Astrophysics Data System (ADS)

    Efendiev, T. Sh.; Katarkevich, V. M.; Rubinov, A. N.

    2007-06-01

    Holographic characteristics of a thick self-developing photosensitive medium - dye-doped jelly-like gelatin are investigated by means of pulsed laser exposure. The experiments were performed using aqueous gelatin solutions of Rhodamin 6G with a layer thickness of 1 mm. The slanted holographic gratings were written with two crossed beams from a frequency-doubled (λ = 532 nm) and Q-switched YAG:Nd laser (τ 0.5 ~ 17 ns, f <= 50 Hz). In the course of recording the hologram was read with the beam from a single-mode He-Ne laser (λ = 632.8 nm) which was not absorbed by the photosensitive medium. The real-time evolution of the grating diffraction efficiency was studied in dependence of the dye and gelatin concentration as well as the writing pulse fluence. It is shown that under appropriate choice of the medium composition and parameters of the recording radiation, it is possible to obtain phase volume holographic gratings with a diffraction efficiency of ~ 87 % and an angular selectivity of ~ 20'.

  14. TRPC6 G757D Loss-of-Function Mutation Associates with FSGS.

    PubMed

    Riehle, Marc; Büscher, Anja K; Gohlke, Björn-Oliver; Kaßmann, Mario; Kolatsi-Joannou, Maria; Bräsen, Jan H; Nagel, Mato; Becker, Jan U; Winyard, Paul; Hoyer, Peter F; Preissner, Robert; Krautwurst, Dietmar; Gollasch, Maik; Weber, Stefanie; Harteneck, Christian

    2016-09-01

    FSGS is a CKD with heavy proteinuria that eventually progresses to ESRD. Hereditary forms of FSGS have been linked to mutations in the transient receptor potential cation channel, subfamily C, member 6 (TRPC6) gene encoding a nonselective cation channel. Most of these TRPC6 mutations cause a gain-of-function phenotype, leading to calcium-triggered podocyte cell death, but the underlying molecular mechanisms are unclear. We studied the molecular effect of disease-related mutations using tridimensional in silico modeling of tetrameric TRPC6. Our results indicated that G757 is localized in a domain forming a TRPC6-TRPC6 interface and predicted that the amino acid exchange G757D causes local steric hindrance and disruption of the channel complex. Notably, functional characterization of model interface domain mutants suggested a loss-of-function phenotype. We then characterized 19 human FSGS-related TRPC6 mutations, the majority of which caused gain-of-function mutations. However, five mutations (N125S, L395A, G757D, L780P, and R895L) caused a loss-of-function phenotype. Coexpression of wild-type TRPC6 and TRPC6 G757D, mimicking heterozygosity observed in patients, revealed a dominant negative effect of TRPC6 G757D. Our comprehensive analysis of human disease-causing TRPC6 mutations reveals loss of TRPC6 function as an additional concept of hereditary FSGS and provides molecular insights into the mechanism responsible for the loss-of-function phenotype of TRPC6 G757D in humans. PMID:26892346

  15. An assessment of the ICE6G_C (VM5A) glacial isostatic adjustment model

    NASA Astrophysics Data System (ADS)

    Purcell, Anthony; Tregoning, Paul; Dehecq, Amaury

    2016-04-01

    The recent release of the next-generation global ice history model, ICE6G_C(VM5a) [Peltier et al., 2015, Argus et al. 2014] is likely to be of interest to a wide range of disciplines including oceanography (sea level studies), space gravity (mass balance studies), glaciology and, of course, geodynamics (Earth rheology studies). In this presentation I will assess some aspects of the ICE6G_C(VM5a) model and the accompanying published data sets. I will demonstrate that the published present-day radial uplift rates are too high along the eastern side of the Antarctic Peninsula (by ˜8.6 mm/yr) and beneath the Ross Ice Shelf (by ˜5 mm/yr). Further, the published spherical harmonic coefficients - which are meant to represent the dimensionless present-day changes due to glacial isostatic adjustment (GIA) - will be shown to contain excessive power for degree ≥ 90, to be physically implausible and to not represent accurately the ICE6G_C(VM5a) model. The excessive power in the high degree terms produces erroneous uplift rates when the empirical relationship of Purcell et al. [2011] is applied but, when correct Stokes' coefficients are used, the empirical relationship will be shown to produce excellent agreement with the fully rigorous computation of the radial velocity field, subject to the caveats first noted by Purcell et al. [2011]. Finally, a global radial velocity field for the present-day GIA signal, and corresponding Stoke's coefficients will be presented for the ICE6GC ice model history using the VM5a rheology model. These results have been obtained using the ANU group's CALSEA software package and can be used to correct satellite altimetry observations for GIA over oceans and by the space gravity community to separate GIA and present-day mass balance change signals without any of the shortcomings of the previously published data-sets. We denote the new data sets ICE6G_ANU.

  16. Spectral characteristics and nonlinear studies of crystal violet dye.

    PubMed

    Sukumaran, V Sindhu; Ramalingam, A

    2006-03-01

    Solid-state dye-doped polymer is an attractive alternative to the conventional liquid dye solution. In this paper, the spectral characteristics and the nonlinear optical properties of the dye crystal violet are studied. The spectral characteristics of crystal violet dye doped poly(methylmethacrylate) modified with additive n-butyl acetate (nBA) are studied by recording its absorption and fluorescence spectra and the results are compared with the corresponding liquid mixture. The nonlinear refractive index of the dye in nBA and dye doped polymer film were measured using z-scan technique, by exciting with He-Ne laser. The results obtained are intercompared. Both the samples of dye crystal violet show a negative nonlinear refractive index. The origin of optical nonlinearity in the dye may be attributed due to laser-heating induced nonlinear effect.

  17. Exciton annihilation in dye-sensitized nanocrystalline semiconductor films

    NASA Astrophysics Data System (ADS)

    Namekawa, Akihiro; Katoh, Ryuzi

    2016-08-01

    Exciton annihilation in dye-sensitized nanocrystalline semiconductor (Al2O3) films has been studied through laser-induced fluorescence spectroscopy. The relative quantum yield of the fluorescence decreases with increasing excitation light intensity, the indication being that exciton annihilation occurred. The rate constants of the annihilation were estimated for three dyes, N719, D149, and MK2, that are known to be sensitizing dyes for efficient dye-sensitized solar cells. The hopping time between dye molecules and the diffusion length of excitons within their lifetime were also estimated to facilitate discussion of the relevance of exciton annihilation to primary processes in dye-sensitized solar cells.

  18. Molecular orientation of submonolayer rhodamine-6G on quartz substrates: A comparative study using reflection and transmission UV-Vis spectroscopy

    SciTech Connect

    Elking, M.D.; He, G.; Xu, Z.

    1996-10-01

    Reflection and transmission UV-Vis spectroscopy have been applied to study the molecular orientation and surface density of rhodamine-6G molecules physisorbed on optically flat quartz (SiO{sub 2}) substrates. Our results have shown that for the {ital s}-polarized excitation, the submonolayer of physisorbed rhodamine-6G dye molecules causes enhanced reflection in the wavelength region from 400 nm to 600 nm where the electronic transition takes place. For the {ital p}-polarized excitation, the reflection is enhanced when the angle of incidence is smaller than Brewster{close_quote}s angle of quartz at 55.6{degree}, and the reflection is reduced when the angle of incidence is larger than Brewster{close_quote}s angle of quartz. An independent method has been established in this paper by which the molecular orientation can be determined accurately by carrying out optical measurements in both the reflection and transmission directions. {copyright} {ital 1996 American Institute of Physics.}

  19. Dye-Sensitization Of Nanocrystalline ZnO Thin Films

    SciTech Connect

    Ajimsha, R. S.; Tyagi, M.; Das, A. K.; Misra, P.; Kukreja, L. M.

    2010-12-01

    Nannocrystalline and nanoporus thin films of ZnO were synthesized on glass substrates by using wet chemical drop casting method. X-ray diffraction measurements on these samples confirmed the formation of ZnO nanocrystallites in hexagonal wurtzite phase with mean size of {approx}20 nm. Photo sensitization of these nanostructured ZnO thin films was carried out using three types of dyes Rhodamine 6 G, Chlorophyll and cocktail of Rhodamine 6 G and Chlorophyll in 1:1 ratio. Dye sensitized ZnO thin films showed enhanced optical absorption in visible spectral region compared to the pristine ZnO thin films.

  20. Photochemical and lasing properties of pyrromethene dyes

    NASA Astrophysics Data System (ADS)

    Jones, Guilford, II; Klueva, Oksana; Kumar, Satish; Pacheco, Dennis P.

    2001-04-01

    Pyrromethene dyes, particularly PM 567, have been studied in liquid media using various spectroscopic techniques. Photodecomposition of dyes was monitored by absorption and fluorescence spectroscopy. In laser flash photolysis experiments on dyes in liquids, phototransients were observed (microsecond time domain) that included dye triplets and at least one other transient of the radical or radical-ion type. Experiments included product studies that allowed identification of major products of photodegradation; an assessment of the effectiveness of known stabilizing additives such as DABCO and butazate was also conducted. Purposes of the work included definition of the roles of energy and electron transfer mechanisms in dye photodegradation and the effects of oxygen or additives in dye media.

  1. Treatment of port wine stains with pulsed dye laser: a retrospective study of 848 cases in Shandong Province, People’s Republic of China

    PubMed Central

    Shi, Wenhao; Wang, Jinliang; Lin, Yan; Geng, Jianhui; Wang, Haixia; Gong, Yueqin; Liu, Huaxu; Zhang, Furen

    2014-01-01

    Background Currently, 595 nm pulsed dye laser (PDL) therapy is offered as one of the effective treatments of port wine stains (PWSs). However, the efficacy of PDL differs in different populations. Objective The purpose of the study was to investigate the efficacy, and related factors, of 595 nm PDL in the treatment of PWSs in Chinese patients with skin type III to IV. Methods A total of 848 cases that were treated with PDL were enrolled and analyzed in this study. An independent dermatologist evaluated these lesions according to the before and after photographs. Results The response rate (RR) of all the 848 PWS patients was 69.9%, within which the cure rate was 6.3%. The patients aged ≤1 year had the highest RR (93.9%), whereas those treated after age 50 reacted the worst (RR =25%). We analyzed the anatomical distribution of the lesion and found that the temporal region had the highest lesion clearance (RR =75.3%), while the extremities had the lowest clearance (RR =44.5%). Compared with the patients whose lesion size was larger than 80 cm2, the patients with small lesion size, of 0–20 cm2, had better clinical effect (RR =73.8% vs 53.2%). The reactions of the patients with hyperplastic lesion were worse than those with red patches (RR =36.4% vs 71.7%). As well, increasing treatment numbers could achieve higher clearance rates (P=0.005). Conclusion The PDL had a relatively high RR but a low clearance rate in Chinese patients with PWS, although the earlier the intervention, the better was the efficacy. The response of PDL was, not only related to the anatomical area, but also, to the lesion size, type of lesion (ie, the presence of existing hyperplastic lesions), and the number of treatment, all of which are essential for the evaluation of therapeutic effect and acquisition of patients consent before treatment. PMID:25548515

  2. An investigation of the application of laser-assisted indocyanine green fluorescent dye angiography in pedicle transverse rectus abdominus myocutaneous breast reconstruction

    PubMed Central

    Newman, Martin I; Samson, Michel C; Tamburrino, Joseph F; Swartz, Kimberly A; Brunworth, Louis

    2011-01-01

    BACKGROUND: Pedicle transverse rectus abdominus myocutaneous (pTRAM) flaps remain the most common method of autologous tissue breast reconstruction. Using pTRAM flaps, complications often arise postoperatively, secondary to inadequate circulation. Tissues from distant angiosomes are associated with poorer perfusion, but this differs among patients. Many modalities have been used to reduce the risk of complications, but none have achieved widespread application. The authors believe that laser-assisted indocyanine green fluorescent dye angiography (LA-ICGA) can potentially reduce the risk of complications. METHODS: In two routine, single-pedicle, ipsilateral pTRAM flaps, LA-ICGA imaging was performed following the division of the distal rectus muscle and deep inferior epigastric pedicle. The resulting images were used to guide design of the flap and debridement. RESULTS: In case 1, good perfusion was observed in zone 1 and part of zone 2. In case 2, good perfusion was observed in zone 1 and 50% of zone 3, with little perfusion in zone 2. In both cases, tissues with poor perfusion were debrided before transfer and inset. In both patients, there were no issues with wound healing, tissue necrosis or fat necrosis. CONCLUSIONS: The variability of perfusion of the pTRAM flap among individuals is well appreciated. LA-ICGA helped to determine the limits of good perfusion and, therefore, the limits of tissue to be preserved for transfer and inset. This helped to avoid harvesting poorly perfused tissue that would have almost certainly experienced necrosis and, ultimately, would have reduced the risk of postoperative complications. PMID:22379372

  3. Dye-enhanced selective photothermal laser-tissue interaction and photodynamic therapy in combination with immunoadjuvant for cancer treatment

    NASA Astrophysics Data System (ADS)

    Chen, Wei R.; Bartels, Kenneth E.; Sun, Jinghai; Liu, Hong; Nordquist, Robert E.; Korbelik, Mladen

    2003-12-01

    Immunoadjuvants have been used to stimulate host immune responses. However, immunoadjuvants alone have not been very successful in treating metastatic tumors. Following the principle of combined therapy in AIDS treatment and in combination chemotherapy, immunoadjuvants have been used in conjunction with other treatment modalities. The current study is an attempt to use both selective photothermal and selective photochemical interactions to accompany a new immunoadjuvant in the treatment of metastatic tumors. The immunoadjuvant, glycated chitosan (GC), has been shown in the previous studies to be effective in inducing immune responses when combined with the treatment of laser irradiation after the intratumoral injection of indocyanine green solution. When glycated chitosan was used with photodynamic therapy (PDT), the treatment effect was significantly increased. Specifically, when glycated chitosan was injected peritumorally after Photofrin-based PDT treatment of EMT6 mammary sarcoma in mice, the tumor-free rate of the treated mice was increased from 38% to 75% using 1.5% GC solution. In mTHPC-based PDT treatment of Line-1 lung adenocarcinoma in mice, the tumor-free rates of treated mice reached 38% while PDT alone did not result in any tumor free mouse. The combination of the immunoadjuvant and selective photophysical interaction may become an effective method to treat tumors with an induced anti-tumor immunity.

  4. Band-edge lasing in Rh6G-doped dichromated gelatin at different excitations

    NASA Astrophysics Data System (ADS)

    Ying, Cui-Feng; Zhou, Wen-Yuan; Ye, Qing; Zhang, Xiao-Liang; Tian, Jian-Guo

    2010-11-01

    One-dimensional photonic crystal band-edge lasing at different excitations was studied experimentally by altering the excitation angle. We considered almost every condition including in-band, out-of-band and near the band edge while keeping the density of states unchanged. Holographic rhodamin 6G-doped dichromated gelatin was used for creating low-threshold photonic band-edge lasing (PBEL). Lasing actions excited near the high-energy and low-energy band edges were observed simultaneously, and their full widths at half maximum were different. The results show that the PBEL intensity and pump efficiency are sensitive to the excitation angle, enhanced obviously at the excitation near the band edge and suppressed distinctly in the band which agreed well with the theoretical prediction. We also demonstrated for the first time that active matters exist not only in the air voids but also in the high-index regions of the gelatin.

  5. Cavity-enhanced spontaneous emission rates for rhodamine 6-G in levitated microdroplets

    SciTech Connect

    Barnes, M.D.; Whitten, W.B.; Ramsey, J.M. ); Arnold, S. )

    1992-01-01

    Fluorescence decay kinetics of Rhodamine 6-G molecules in levitated glycerol microdroplets (4--20 microns in diameter) have been investigated to determine the effects of spherical cavity resonances on spontaneous emission rates. For droplet diameters greater than 10 microns, the fluorescence lifetime is essentially the same as in bulk glycerol. As the droplet diameter is decreased below 10 microns, bi-exponential decay behavior is observed with a slow component whose rate is similar to bulk glycerol, and a fast component whose rate is as much as a factor of 10 larger than the bulk decay rate. This fast component is attributed to cavity enhancement of the spontaneous emission rate and, within the weak coupling approximation, a value for the homogeneous linewidth at room temperature can be estimated from the fluorescence lifetime data.

  6. Cavity-enhanced spontaneous emission rates for rhodamine 6-G in levitated microdroplets

    SciTech Connect

    Barnes, M.D.; Whitten, W.B.; Ramsey, J.M.; Arnold, S.

    1992-11-01

    Fluorescence decay kinetics of Rhodamine 6-G molecules in levitated glycerol microdroplets (4--20 microns in diameter) have been investigated to determine the effects of spherical cavity resonances on spontaneous emission rates. For droplet diameters greater than 10 microns, the fluorescence lifetime is essentially the same as in bulk glycerol. As the droplet diameter is decreased below 10 microns, bi-exponential decay behavior is observed with a slow component whose rate is similar to bulk glycerol, and a fast component whose rate is as much as a factor of 10 larger than the bulk decay rate. This fast component is attributed to cavity enhancement of the spontaneous emission rate and, within the weak coupling approximation, a value for the homogeneous linewidth at room temperature can be estimated from the fluorescence lifetime data.

  7. Fusion of Renewable Ring Resonator Lasers and Ultrafast Laser Inscribed Photonic Waveguides

    PubMed Central

    Chandrahalim, Hengky; Rand, Stephen C.; Fan, Xudong

    2016-01-01

    We demonstrated the monolithic integration of reusable and wavelength reconfigurable ring resonator lasers and waveguides of arbitrary shapes to out-couple and guide laser emission on the same fused-silica chip. The ring resonator hosts were patterned by a single-mask standard lithography, whereas the waveguides were inscribed in the proximity of the ring resonator by using 3-dimensional femtosecond laser inscription technology. Reusability of the integrated ring resonator – waveguide system was examined by depositing, removing, and re-depositing dye-doped SU-8 solid polymer, SU-8 liquid polymer, and liquid solvent (toluene). The wavelength reconfigurability was validated by employing Rhodamine 6G (R6G) and 3,3′-Diethyloxacarbocyanine iodide (CY3) as exemplary gain media. In all above cases, the waveguide was able to couple out and guide the laser emission. This work opens a door to reconfigurable active and passive photonic devices for on-chip coherent light sources, optical signal processing, and the investigation of new optical phenomena. PMID:27600872

  8. Fusion of Renewable Ring Resonator Lasers and Ultrafast Laser Inscribed Photonic Waveguides

    NASA Astrophysics Data System (ADS)

    Chandrahalim, Hengky; Rand, Stephen C.; Fan, Xudong

    2016-09-01

    We demonstrated the monolithic integration of reusable and wavelength reconfigurable ring resonator lasers and waveguides of arbitrary shapes to out-couple and guide laser emission on the same fused-silica chip. The ring resonator hosts were patterned by a single-mask standard lithography, whereas the waveguides were inscribed in the proximity of the ring resonator by using 3-dimensional femtosecond laser inscription technology. Reusability of the integrated ring resonator – waveguide system was examined by depositing, removing, and re-depositing dye-doped SU-8 solid polymer, SU-8 liquid polymer, and liquid solvent (toluene). The wavelength reconfigurability was validated by employing Rhodamine 6G (R6G) and 3,3‧-Diethyloxacarbocyanine iodide (CY3) as exemplary gain media. In all above cases, the waveguide was able to couple out and guide the laser emission. This work opens a door to reconfigurable active and passive photonic devices for on-chip coherent light sources, optical signal processing, and the investigation of new optical phenomena.

  9. Fusion of Renewable Ring Resonator Lasers and Ultrafast Laser Inscribed Photonic Waveguides.

    PubMed

    Chandrahalim, Hengky; Rand, Stephen C; Fan, Xudong

    2016-01-01

    We demonstrated the monolithic integration of reusable and wavelength reconfigurable ring resonator lasers and waveguides of arbitrary shapes to out-couple and guide laser emission on the same fused-silica chip. The ring resonator hosts were patterned by a single-mask standard lithography, whereas the waveguides were inscribed in the proximity of the ring resonator by using 3-dimensional femtosecond laser inscription technology. Reusability of the integrated ring resonator - waveguide system was examined by depositing, removing, and re-depositing dye-doped SU-8 solid polymer, SU-8 liquid polymer, and liquid solvent (toluene). The wavelength reconfigurability was validated by employing Rhodamine 6G (R6G) and 3,3'-Diethyloxacarbocyanine iodide (CY3) as exemplary gain media. In all above cases, the waveguide was able to couple out and guide the laser emission. This work opens a door to reconfigurable active and passive photonic devices for on-chip coherent light sources, optical signal processing, and the investigation of new optical phenomena. PMID:27600872

  10. Fusion of Renewable Ring Resonator Lasers and Ultrafast Laser Inscribed Photonic Waveguides.

    PubMed

    Chandrahalim, Hengky; Rand, Stephen C; Fan, Xudong

    2016-09-07

    We demonstrated the monolithic integration of reusable and wavelength reconfigurable ring resonator lasers and waveguides of arbitrary shapes to out-couple and guide laser emission on the same fused-silica chip. The ring resonator hosts were patterned by a single-mask standard lithography, whereas the waveguides were inscribed in the proximity of the ring resonator by using 3-dimensional femtosecond laser inscription technology. Reusability of the integrated ring resonator - waveguide system was examined by depositing, removing, and re-depositing dye-doped SU-8 solid polymer, SU-8 liquid polymer, and liquid solvent (toluene). The wavelength reconfigurability was validated by employing Rhodamine 6G (R6G) and 3,3'-Diethyloxacarbocyanine iodide (CY3) as exemplary gain media. In all above cases, the waveguide was able to couple out and guide the laser emission. This work opens a door to reconfigurable active and passive photonic devices for on-chip coherent light sources, optical signal processing, and the investigation of new optical phenomena.

  11. A study of the interaction between rhodamine 6g and hydroxy propyl β-cyclodextrin by steady state fluorescence

    NASA Astrophysics Data System (ADS)

    Bakkialakshmi, S.; menaka, T.

    2011-10-01

    The binding of rhodamine 6G and hydroxy propyl β-cyclodextrin (Hβ-CD) was investigated measuring fluorescence and absorption at pH 7.0. The solid inclusion complex of Rh6G and Hβ-CD has been studied by Ultraviolet (UV) spectroscopy, Fluorimetry, Fourier Transform Infrared (FTIR), 1H Nuclear Magnetic Resonance ( 1HNMR) and in the Scanning Electron Microscope (SEM). Association constant Kg and Ke were determined by the enhancement of the fluorescence of rhodamine 6G in the presence of Hβ-CD. Fluorescence of Rh6G is generally enhanced, in complexes of Rh6G and β-Cyclodextrin in aqueous solutions. The free energy change for the ground state (Δ Gg) and for the excited state (Δ Ge) have also been determined. The experimental results indicated that the inclusion process is an exothermic and spontaneous.

  12. A study of the interaction between rhodamine 6g and hydroxy propyl β-cyclodextrin by steady state fluorescence.

    PubMed

    Bakkialakshmi, S; Menaka, T

    2011-10-15

    The binding of rhodamine 6G and hydroxy propyl β-cyclodextrin (Hβ-CD) was investigated measuring fluorescence and absorption at pH 7.0. The solid inclusion complex of Rh6G and Hβ-CD has been studied by Ultraviolet (UV) spectroscopy, Fluorimetry, Fourier Transform Infrared (FTIR), (1)H Nuclear Magnetic Resonance ((1)HNMR) and in the Scanning Electron Microscope (SEM). Association constant K(g) and K(e) were determined by the enhancement of the fluorescence of rhodamine 6G in the presence of Hβ-CD. Fluorescence of Rh6G is generally enhanced, in complexes of Rh6G and β-Cyclodextrin in aqueous solutions. The free energy change for the ground state (ΔG(g)) and for the excited state (ΔG(e)) have also been determined. The experimental results indicated that the inclusion process is an exothermic and spontaneous.

  13. Fluorescence monitor method for measuring effective absorption coefficients of molecular rovibronic transitions using tunable dye laser excitation: The case of absorber linewidth narrower than the laser linewidth applied to H/sub 2/CO

    SciTech Connect

    Fairchild, P.W.; Garland, N.L.; Howard, W.E. III; Lee, E.K.C.

    1980-10-01

    A technique for measuring ''effective'' absorption coefficients is described. It circumvents deviations from Beer's law caused when the excitation source bandwidth is larger than the absorber bandwidth. The technique employs a fluorescence cell placed after an absorption cell to selectively monitor absorption in the center region of the source line. Model calculations relating the fluorescence intensity to source and absorber line shapes indicate that this method should yield linear Beer's law plots for moderate values of k/sub 0/Nl and ..cap alpha.., where ..cap alpha.. is the ratio of the source bandwidth to the absorber bandwidth. This technique has been applied to a number of single rotational levels in the 4/sup 1//sub 0/ transition of the H/sub 2/CO A /sup 1/A/sub 2/reverse arrowX /sup 1/A/sub 1/ system using pulsed, tunable dye laser excitation. The effective absorption coefficients determined experimentally have been compared to the theoretically calculated absorption coefficients.

  14. Investigation of the effect of the duration of pumping on the spectral and spatial--angular characteristics of lasing by rhodamine 6G solutions in a short resonator

    SciTech Connect

    Smirnov, V.S.; Studenov, V.I.

    1985-10-01

    An investigation of the spectral and spatial--angular characteristics of radiation of a laser based on an ethanol solution of rhodamine 6G in a short plane-parallel nonselective resonator with longitudinal pumping by laser radiation of nano- and microsecond duration was performed. It was shown that in all cases formation of the characteristics of the radiation investigated is due to the resonator parameters of the Fabry-Perot interferometer used as a resonator. It was noted that on an increase in the duration of excitation a weak short-wave shift of the maximum of the lasing spectrum with a simultaneous blurring of the interference structure of the spectrum and of the radiation field occurs. The indicated facts are explained by the difference of the energy contribution to the lasing volume, which leads both to homogeneous heating of the solution in the lasing zone and to radial inhomogeneity of heat release, degrading the conditions of inteference.

  15. Time resolved FRET measurement in various heterogeneous media using merocyanine dye as a donor

    NASA Astrophysics Data System (ADS)

    Kedia, Niraja; Bagchi, Sanjib

    2015-06-01

    Ultrafast fluorescence resonance energy transfer (FRET) from a merocyanine dye to a Rhodamine 6G (R6G) molecule in micelles formed by the surfactants SDS and DTAB and also in a catanionic vesicle formed by SDS and DTAB has been studied by picosecond time resolved emission spectroscopy. Here the dye acts as a donor molecule and R6G acts as the acceptor molecule. Multiple timescales of FRET have been detected, namely, an ultrafast component of 100-500 ps and relatively long component (1800-3300 ps). The different time scales are attributed to different donor-acceptor distances.

  16. Time resolved FRET measurement in various heterogeneous media using merocyanine dye as a donor.

    PubMed

    Kedia, Niraja; Bagchi, Sanjib

    2015-06-15

    Ultrafast fluorescence resonance energy transfer (FRET) from a merocyanine dye to a Rhodamine 6G (R6G) molecule in micelles formed by the surfactants SDS and DTAB and also in a catanionic vesicle formed by SDS and DTAB has been studied by picosecond time resolved emission spectroscopy. Here the dye acts as a donor molecule and R6G acts as the acceptor molecule. Multiple timescales of FRET have been detected, namely, an ultrafast component of 100-500 ps and relatively long component (1800-3300 ps). The different time scales are attributed to different donor-acceptor distances.

  17. Strong coupling between Rhodamine 6G and localized surface plasmon resonance of immobile Ag nanoclusters fabricated by direct current sputtering

    NASA Astrophysics Data System (ADS)

    Fang, Yingcui; Blinn, Kevin; Li, Xiaxi; Weng, Guojun; Liu, Meilin

    2013-04-01

    We made clean silver nano-clusters (AgNCs) on glass substrates by DC magnetron sputtering of a high purity Ag target in a high vacuum chamber. The AgNCs film shows strong localized surface plasmon resonance (LSPR) due to the coupling among Ag nanoparticles in the AgNCs and the coupling between AgNCs. The LSPR indicates strong coupling with Rhodamine 6G (R6G) adsorbed on the AgNC surface, which enhances the R6G absorption intensity and broadens the absorption wavelength range. This result promotes plasmonic nanoparticles to be better used in solar cells.

  18. Dye-doped organosilicate nanoparticles as cell-preserving labels for photoacoustic signal generation.

    PubMed

    Ramirez-Perez, Francisco I; Gutiérrez-Juárez Gerardo; Bok, Sangho; Gangopadhyay, Keshab; Gangopadhyay, Shubhra; Baker, Gary A; Polo-Parada, Luis

    2014-11-01

    Nanoparticle-assisted ultrasound generation by pulsed laser or photoacoustic (PA) techniques has been employed in the study of several tissues both in vivo and in vitro. Among the many applications of this technology, the detection of few cells in vitro is of particular interest. However, the toxicity induced by laser irradiation used for PA signal generation, whether in the absence or the presence of PA enhancers, within single isolated cells has not yet been investigated in detail. Herein, we report our studies of the cellular health of two different nanoparticle-labeled cell lines one hour after being subjected to a single laser pulse in vitro. We selected for this study an Hs936 skin epithelial melanoma cell line, which can be naturally detected photoacoustically, as well as a T47D human mammary breast gland epithelial cell line which has proven difficult to detect photoacoustically due to the absence of natural melanin. We have evaluated the amplitude of the PA signal derived from these two cell types, unlabeled and labeled with nanoparticles of two types (gold nanoparticles, AuNPs, or rhodamine 6G-doped organosilicate nanoparticles, R6G-NPOs), and assessed their health one hour subsequent to laser treatment. The current work corroborates previous findings that, for unlabeled cells, Hs936 produces a detectable PA signal whereas the T47D line does not. Cells labeled with AuNPs or R6G-NPOs produced a detectable PA signal of similar amplitude for the two cell lines. A significant number of Hs936 cells (both unlabeled cells and those labeled with AuNPs) exhibited cell nuclei alterations, as revealed by DAPI staining conducted an hour after photo treatment. Remarkably, the T47D cells suffered damage only when labeled with AuNPs. A significant finding, the R6G-NPOs proved capable of non-destructive PA signal generation in both cell types. Our findings advocate a transformational path forward for the use of dye-doped silicate nanoparticles in cell-compatible PA

  19. Central Shops Burning/Rubble Pit 631-6G Additonal Sampling and Monitor Well Installation Report

    SciTech Connect

    Palmer, E.

    1995-02-01

    The Central Shops Burning/Rubble Pit 631-6G was constructed in 1951 as an unlined earthen pit in surficial sediments for disposal and incineration of potentially hazardous substances, such as metals and organic solvents.

  20. Rh6G released from solid and nanoporous SiO2 spheres prepared by sol-gel route

    NASA Astrophysics Data System (ADS)

    García-Macedo, J. A.; Francisco S., P.; Franco, A.

    2015-10-01

    Porous silica nanoparticles are considering good systems for drug cargo and liquid separation. In this work we studied the release of rhodamine 6G (Rh6G) from solid and porous silica nanoparticles. Solid and porous SiO2 spheres were prepared by sol-gel method. Nanoporous channels were produced by using a surfactant that was removed by chemical procedure. Rh6G was incorporated into the channels by impregnation. The hexagonal structure of the pores was detected by XRD and confirmed by HRTEM micrographs. Rh6G released from the particles by stirring them in water at controlled speed was studied as function of time by photoluminescence. Released ratio was faster in the solid nanoparticles than in the porous ones. In the last case, a second release mechanism was observed. It was related with rhodamine coming out from the porous.

  1. Highly efficient solid-state distributed feedback dye laser based on polymer-filled nanoporous glass composite excited by a diode-pumped solid-state Nd:LSB microlaser.

    PubMed

    Katarkevich, Vasili M; Rubinov, Anatoli N; Efendiev, Terlan Sh; Anufrik, Slavamir S; Koldunov, Modest F

    2015-09-10

    Realization of a compact, robust, highly stable, and efficient solid-state distributed feedback (DFB) dye laser based on pyrromethene 580-doped modified poly-(methyl methacrylate) embedded into nanoporous glass host is reported. A diode-pumped solid-state STA01SH-500 Nd:LSB microlaser (λ=532  nm; τ0.5∼0.5  ns; EP≤80  μJ; f≤500  Hz) is used as a pump source. When pumped well above threshold, a DFB laser emits a train of ultrashort pulses (τ≤1  ns; τ0.5<0.5  ns; Δλ0.5≤0.01  nm), while at excitation intensities not far from threshold, single transform-limited picosecond pulses (τ0.5≤40  ps; τ0.5Δν0.5∼0.3), tunable from 541 to 598 nm, are generated. The DFB lasing efficiency reaches ∼60% upon an energy stability of ∼1.4% and an overall service life of the active element of ∼9×107 laser shots. More than an order of magnitude increase in the temperature stability of a lasing wavelength as compared with ethanol solutions of laser dyes is practically demonstrated.

  2. Highly efficient solid-state distributed feedback dye laser based on polymer-filled nanoporous glass composite excited by a diode-pumped solid-state Nd:LSB microlaser.

    PubMed

    Katarkevich, Vasili M; Rubinov, Anatoli N; Efendiev, Terlan Sh; Anufrik, Slavamir S; Koldunov, Modest F

    2015-09-10

    Realization of a compact, robust, highly stable, and efficient solid-state distributed feedback (DFB) dye laser based on pyrromethene 580-doped modified poly-(methyl methacrylate) embedded into nanoporous glass host is reported. A diode-pumped solid-state STA01SH-500 Nd:LSB microlaser (λ=532  nm; τ0.5∼0.5  ns; EP≤80  μJ; f≤500  Hz) is used as a pump source. When pumped well above threshold, a DFB laser emits a train of ultrashort pulses (τ≤1  ns; τ0.5<0.5  ns; Δλ0.5≤0.01  nm), while at excitation intensities not far from threshold, single transform-limited picosecond pulses (τ0.5≤40  ps; τ0.5Δν0.5∼0.3), tunable from 541 to 598 nm, are generated. The DFB lasing efficiency reaches ∼60% upon an energy stability of ∼1.4% and an overall service life of the active element of ∼9×107 laser shots. More than an order of magnitude increase in the temperature stability of a lasing wavelength as compared with ethanol solutions of laser dyes is practically demonstrated. PMID:26368971

  3. Acne vulgaris in the context of complex medical co-morbities: the management of severe acne vulgaris in a female with retinitis pigmentosa - utilizing pulse dye laser in conjunction with medical therapy.

    PubMed

    Shariff, Ayesha; Keck, Laura; Zlotoff, Barrett

    2014-03-01

    Acne vulgaris is a pervasive inflammatory disorder of the skin, with multiple etiologies and treatment options. Although first-line therapies exist, it is often the case that a patient will present with an underlying disorder that prohibits the use of most currently accepted treatment modalities. We present a patient with severe acne vulgaris and a history of retinitis pigmentosa who was treated with 595 nanometer pulsed dye laser therapy, in conjunction with therapeutic alternatives to first-line acne medications. Our patient exhibited a significant and sustained improvement with the combined use of 595 nanometer pulsed dye laser, Yaz (drospirenone-ethinyl estradiol), dapsone, topical metronidazole, sodium-sulfacetamide wash, and topical azelaic acid. The positive results in this case, suggest that this combined treatment modality may serve as an example of a safe and effective treatment alternative in the management of acne vulgaris complicated by medical co-morbidities that contraindicate the use of most first-line treatment options. PMID:24656277

  4. Spectroscopic Studies of Abiotic and Biological Nanomaterials: Silver Nanoparticles, Rhodamine 6G Adsorbed on Graphene, and c-Type Cytochromes and Type IV Pili in Geobacter sulfurreducens

    NASA Astrophysics Data System (ADS)

    Thrall, Elizabeth S.

    This thesis describes spectroscopic studies of three different systems: silver nanoparticles, the dye molecule rhodamine 6G adsorbed on graphene, and the type IV pili and c-type cytochromes produced by the dissimilatory metal-reducing bacterium Geobacter sulfurreducens. Although these systems are quite different in some ways, they can all be considered examples of nanomaterials. A nanomaterial is generally defined as having at least one dimension below 100 nm in size. Silver nanoparticles, with sub-100 nm size in all dimensions, are examples of zero-dimensional nanomaterials. Graphene, a single atomic layer of carbon atoms, is the paradigmatic two-dimensional nanomaterial. And although bacterial cells are on the order of 1 μm in size, the type IV pili and multiheme c-type cytochromes produced by G. sulfurreducens can be considered to be one- and zero-dimensional nanomaterials respectively. A further connection between these systems is their strong interaction with visible light, allowing us to study them using similar spectroscopic tools. The first chapter of this thesis describes research on the plasmon-mediated photochemistry of silver nanoparticles. Silver nanoparticles support coherent electron oscillations, known as localized surface plasmons, at resonance frequencies that depend on the particle size and shape and the local dielectric environment. Nanoparticle absorption and scattering cross-sections are maximized at surface plasmon resonance frequencies, and the electromagnetic field is amplified near the particle surface. Plasmonic effects can enhance the photochemistry of silver particles alone or in conjunction with semiconductors according to several mechanisms. We study the photooxidation of citrate by silver nanoparticles in a photoelectrochemical cell, focusing on the wavelength-dependence of the reaction rate and the role of the semiconductor substrate. We find that the citrate

  5. Using natural variation to investigate the function of individual amino acids in the sucrose-binding box of fructan:fructan 6G-fructosyltransferase (6G-FFT) in product formation.

    PubMed

    Ritsema, Tita; Verhaar, Auke; Vijn, Irma; Smeekens, Sjef

    2005-07-01

    Enzymes of the glycosyl hydrolase family 32 are highly similar with respect to primary sequence but catalyze divergent reactions. Previously, the importance of the conserved sucrose-binding box in determining product specificity of onion fructan:fructan 6G-fructosyltransferase (6G-FFT) was established [Ritsema et al., 2004, Plant Mol. Biol. 54: 853-863]. Onion 6G-FFT synthesizes the complex fructan neo-series inulin by transferring fructose residues to either a terminal fructose or a terminal glucose residue. In the present study we have elucidated the molecular determinants of product specificity by substitution of individual amino acids of the sucrose binding box with amino acids that are present on homologous positions in other fructosyltransferases or vacuolar invertases. Substituting the presumed nucleophile Asp85 of the beta-fructosidase motif resulted in an inactive enzyme. 6G-FFT mutants S87N and S87D did not change substrate or product specificities, whereas mutants N84Y and N84G resulted in an inactive enzyme. Most interestingly, mutants N84S, N84A, and N84Q added fructose residues preferably to a terminal fructose and hardly to the terminal glucose. This resulted in the preferential production of inulin-type fructans. Combining mutations showed that amino acid 84 determines product specificity of 6G-FFT irrespective of the amino acid at position 87. PMID:16158237

  6. Photochemistry of triarylmethane dyes bound to proteins

    NASA Astrophysics Data System (ADS)

    Indig, Guilherme L.

    1996-04-01

    Triarylmethanes represent a class of cationic dyes whose potential as photosensitizers for use in photodynamic therapy of neoplastic diseases has never been comprehensively evaluated. Here, the laser-induced photodecomposition of three triarylmethane dyes, crystal violet, ethyl violet, and malachite green, non-covalently bound to bovine serum albumin (a model biological target) was investigated. Upon laser excitation at 532 nm, the bleaching of the corresponding dye-protein molecular complexes follows spectroscopic patterns that suggest the formation of reduced forms of the dyes as major reaction photoproducts. That implies that an electron or hydrogen atom transfer from the protein to the dye's moiety within the guest-host complex is the first step of the photobleaching process. Since the availability of dissolved molecular oxygen was not identified as a limiting factor for the phototransformations to occur, these dyes can be seen as potential phototherapeutic agents for use in hypoxic areas of tumors. These triarylmethane dyes strongly absorb at relatively long wavelengths (absorption maximum around 600 nm; (epsilon) max approximately equals 105 M-1 cm-1), and only minor changes in their absorption characteristics are observed upon binding to the protein. However the binding event leads to a remarkable increase in their fluorescence quantum yield and photoreactivity.

  7. Uniform silica nanoparticles encapsulating two-photon absorbing fluorescent dye

    SciTech Connect

    Wu Weibing; Liu Chang; Wang Mingliang; Huang Wei; Zhou Shengrui; Jiang Wei; Sun Yueming; Cui Yiping; Xu Chunxinag

    2009-04-15

    We have prepared uniform silica nanoparticles (NPs) doped with a two-photon absorbing zwitterionic hemicyanine dye by reverse microemulsion method. Obvious solvatochromism on the absorption spectra of dye-doped NPs indicates that solvents can partly penetrate into the silica matrix and then affect the ground and excited state of dye molecules. For dye-doped NP suspensions, both one-photon and two-photon excited fluorescence are much stronger and recorded at shorter wavelength compared to those of free dye solutions with comparative overall dye concentration. This behavior is possibly attributed to the restricted twisted intramolecular charge transfer (TICT), which reduces fluorescence quenching when dye molecules are trapped in the silica matrix. Images from two-photon laser scanning fluorescence microscopy demonstrate that the dye-doped silica NPs can be actively uptaken by Hela cells with low cytotoxicity. - Graphical abstract: Water-soluble silica NPs doped with a two-photon absorbing zwitterionic hemicyanine dye were prepared. They were found of enhanced one-photon and two-photon excited fluorescence compared to free dye solutions. Images from two-photon laser scanning fluorescence microscopy demonstrate that the dye-doped silica NPs can be actively uptaken by Hela cells.

  8. A highly selective and sensitive photoswitchable fluorescent probe for Hg2+ based on bisthienylethene-rhodamine 6G dyad and for live cells imaging.

    PubMed

    Xu, Li; Wang, Sheng; Lv, Yingnian; Son, Young-A; Cao, Derong

    2014-07-15

    A new photochromic diarylethene derivative bearing rhodamine 6G dimmer as a fluorescent molecular probe is designed and synthesized successfully. All the compounds are characterized by nuclear magnetic resonance and mass spectrometry. The bisthienylethene-rhodamine 6G dyad exhibit excellent phtochromism with reversibly color and fluorescence changes alternating irradiation with ultraviolet and visible light. Upon addition of Hg(2+), its color changes from colorless to red and its fluorescence is remarkably enhanced. Whereas other ions including K(+), Na(+), Ca(2+), Mg(2+), Fe(2+), Co(2+), Ni(2+), Cu(2+), Zn(2+), Mn(2+), Pb(2+), Ni(2+), Fe(3+), Al(3+), Cr(3+) and so on induce basically no spectral changes, which constitute a highly selective and sensitive photoswitchable fluorescent probe toward Hg(2+). Furthermore, by means of laser confocal scanning microscopy experiments, it is demonstrated that this probe can be applied for live cell imaging and monitoring Hg(2+) in living lung cancer cells with satisfying results, which shows its value of potential application in environmental and biological systems.

  9. Characterization of the fluorescence correlation spectroscopy (FCS) standard Rhodamine 6G and calibration of its diffusion coefficient in aqueous solutions

    SciTech Connect

    Majer, G.; Melchior, J. P.

    2014-03-07

    Precise diffusion measurements of rhodamine 6G (Rh6G) dissolved in D{sub 2}O at concentrations between 50 and 200 μM were carried out in the temperature range from 280 to 320 K using pulsed field gradient nuclear magnetic resonance (PFG-NMR). The obtained diffusion coefficients can be used as a calibration reference in fluorescence correlation spectroscopy (FCS). Besides measuring the diffusivity of Rh6G, the diffusion coefficient of the solvent in the same system could be determined in parallel by PFG-NMR as the resonances of water and Rh6G are well separated in the {sup 1}H NMR spectrum. To analyze the differences due to the isotope effect of the solvent (D{sub 2}O vs. H{sub 2}O), the correlation time τ{sub D} of Rh6G was measured by FCS in both D{sub 2}O and H{sub 2}O. The obtained isotopic correction factor, τ{sub D}(D{sub 2}O)/τ{sub D}(H{sub 2}O) = 1.24, reflects the isotope effect of the solvent´s self-diffusion coefficients as determined previously by PFG-NMR.

  10. Copy Number Variation and Transposable Elements Feature in Recent, Ongoing Adaptation at the Cyp6g1 Locus

    PubMed Central

    Schmidt, Joshua M.; Good, Robert T.; Appleton, Belinda; Sherrard, Jayne; Raymant, Greta C.; Bogwitz, Michael R.; Martin, Jon; Daborn, Phillip J.; Goddard, Mike E.; Batterham, Philip; Robin, Charles

    2010-01-01

    The increased transcription of the Cyp6g1 gene of Drosophila melanogaster, and consequent resistance to insecticides such as DDT, is a widely cited example of adaptation mediated by cis-regulatory change. A fragment of an Accord transposable element inserted upstream of the Cyp6g1 gene is causally associated with resistance and has spread to high frequencies in populations around the world since the 1940s. Here we report the existence of a natural allelic series at this locus of D. melanogaster, involving copy number variation of Cyp6g1, and two additional transposable element insertions (a P and an HMS-Beagle). We provide evidence that this genetic variation underpins phenotypic variation, as the more derived the allele, the greater the level of DDT resistance. Tracking the spatial and temporal patterns of allele frequency changes indicates that the multiple steps of the allelic series are adaptive. Further, a DDT association study shows that the most resistant allele, Cyp6g1-[BP], is greatly enriched in the top 5% of the phenotypic distribution and accounts for ∼16% of the underlying phenotypic variation in resistance to DDT. In contrast, copy number variation for another candidate resistance gene, Cyp12d1, is not associated with resistance. Thus the Cyp6g1 locus is a major contributor to DDT resistance in field populations, and evolution at this locus features multiple adaptive steps occurring in rapid succession. PMID:20585622

  11. Ultraviolet lasers. Citations from the International Aerospace Abstracts data base

    NASA Technical Reports Server (NTRS)

    Mauk, S. C.

    1980-01-01

    Reports cited from the international literature describe various aspects of ultraviolet lasers including laser output, far ultraviolet radiation, electron pumping, optical pumping, and laser materials. Gas lasers, pulsed lasers, dye lasers, CO2 lasers, xenon fluoride lasers, and transversely excited atmospheric (TEA) lasers are considered. This updated bibliography contains 283 citations, 66 of which are new additions to the previous edition.

  12. Fluorescence depolarization of rhodamine 6G in glycerol: a photon-counting test of three-dimensional excitation transport theory

    SciTech Connect

    Anfinrud, P.A.; Hart, D.E.; Hedstrom, J.F.; Struve, W.S.

    1986-05-22

    Time-correlated photon counting has been used to measure fluorescence concentration depolarization for rhodamine 6G in glycerol. The excitation transport theory developed by Gochanour, Andersen, and Fayer yields good approximations to the experimental decay profiles over the concentration range 1.7 x 10/sup -4/ to 2.4 x 10/sup -3/ M. Although the differences between optimized theoretical and experimental profiles are fractionally small, they are readily characterized under present counting statistics. They prove to be dominated by experimental artifacts, arising from excitation trapping by rhodamine 6G aggregates and from self-absorption in solution cells thicker than approx. 10 ..mu..m.

  13. Optical devices based on dye-coated superconductor junctions: An example of a composite molecule-superconductor device

    SciTech Connect

    Zhao, J.; Jurbergs, D.; Yamazi, B.; McDevitt, J.T.

    1992-03-25

    High-temperature superconductors provide new opportunities as materials used in the construction of hybrid molecule-superconductor components. Here, the authors describe fabrication methods for and operation of optical sensors based on molecular dye-coated superconductor junctions. Devices prepared from yttrium barium cuprates and using octaethylporphyrin, phthalocyanine, and rhodamine 6G as dyes have been prepared. 9 refs., 1 fig.

  14. Textile dye dermatitis.

    PubMed

    Hatch, K L; Maibach, H I

    1995-04-01

    The literature concerning textile dye dermatitis published during the last decade was reviewed. Sixty-one cases of dye-allergic contact dermatitis in which the presentation or course of the dermatitis was unusual or the dye allergen was one not previously reported have been described. The four new dye allergens discovered were Disperse Blue 106, Disperse Blue 85, Disperse Brown 1, and Basic Red 46. The incidence of dye dermatitis varied from 1% to 15.9% depending on the country, patient sample, and number of dyes in the patch test series. The 10 new dye allergens discovered in these studies were Disperse Blue 153, Disperse Orange 13, Basic Black 1, Basic Brown 1, the acid dyes Supramine Yellow and Supramine Red, the direct dye Diazol Orange, the basic dye Brilliant Green, Turquoise Reactive, and Neutrichrome Red. Disperse Blue 106 and Disperse Blue 124 were shown to be the strongest clothing dye sensitizers to date. Standard screening patch test series were found to be inadequate for the detection of textile dye sensitivity; therefore textile dye patch test series should be used. It is difficult to determine whether the incidence of dye dermatitis is increasing or decreasing because controlled epidemiologic studies are lacking, but data suggest that textile dye sensitivity is more common than previously believed.

  15. Ag-nanoparticles on UF-microsphere as an ultrasensitive SERS substrate with unique features for rhodamine 6G detection.

    PubMed

    Hao, Zhixian; Mansuer, Mulati; Guo, Yuqing; Zhu, Zhirong; Wang, Xiaogang

    2016-01-01

    Urea and formaldehyde (UF) microsphere (MS) adsorbing Ag nanoparticles (NPs) was employed as a surface enhanced Raman scattering (SERS) substrate for rhodamine 6G (R6G) detection. The UF MSs and citrate-reduced Ag colloid supplying Ag NPs are synthesized separately and all the subsequent fabrication procedure is then implemented within 2 mL centrifuge tube. Influences of the composition and drying temperature of the UF MSs and the drying method and modification of AgNP/UFMS on the final SERS performance have first been reported. Excess formaldehyde useful in the formation of UF MSs again plays an important role in the SERS detection. Some interesting phenomena in the approach, such as swelling/deswelling of UF MSs and R6G diffusion within hydrophilic environment of UF MSs, are found to be of variable factors affecting the SERS performance. The substrate AgNP/UFMS confidently achieves a detection limit of 10(-13) M R6G and can be used as a simple and effective platform in the SERS spectroscopy. PMID:26695301

  16. LSP spectral changes correlating with SERS activation and quenching for R6G on immobilized Ag nanoparticles

    NASA Astrophysics Data System (ADS)

    Futamata, M.; Maruyama, Y.

    2008-10-01

    In terms of chemical enhancement in Surface Enhanced Raman Scattering (SERS), we investigated the effect of halide and other anions to rhodamine 6G (R6G) adsorbed Ag particles that were immobilized on the substrates. The residual species on chemically prepared Ag particles such as citrate or a-carbon were thoroughly substituted by various anions, e.g., Cl-, Br-, I-, SCN-, CN-, or S2O3 2- anions, whose adsorption features are elucidated by the formation constants for AgX2 ( m-1)-, here X denotes the above anions. In particular, Cl-, Br-, or SCN- ions activated SERS of R6G via intrinsic electronic interaction with Ag, whereas CN-, S2O3 2-, or I- anions quenched it due to their exclusive adsorption onto the Ag surfaces. We found that the activation process with the anions commonly yields a marked blue-shift of the coupled plasmon peak from ca. 650-700 to 500-550 nm in elastic scattering. It is rationalized by slight increase of the gap size between adjacent Ag nanoparticles by only ca. 1 nm based on theoretical simulations. This is probably caused by slight dissolution, oxidative etching, of the particles according to large formation constants of the complexes. Consequently, partly remaining negative charges on the Ag surface, and a slight increase in the gap size, providing huge electric field, facilitated R6G cations to adsorb on the nanoparticles, especially at the junction.

  17. Ag-nanoparticles on UF-microsphere as an ultrasensitive SERS substrate with unique features for rhodamine 6G detection.

    PubMed

    Hao, Zhixian; Mansuer, Mulati; Guo, Yuqing; Zhu, Zhirong; Wang, Xiaogang

    2016-01-01

    Urea and formaldehyde (UF) microsphere (MS) adsorbing Ag nanoparticles (NPs) was employed as a surface enhanced Raman scattering (SERS) substrate for rhodamine 6G (R6G) detection. The UF MSs and citrate-reduced Ag colloid supplying Ag NPs are synthesized separately and all the subsequent fabrication procedure is then implemented within 2 mL centrifuge tube. Influences of the composition and drying temperature of the UF MSs and the drying method and modification of AgNP/UFMS on the final SERS performance have first been reported. Excess formaldehyde useful in the formation of UF MSs again plays an important role in the SERS detection. Some interesting phenomena in the approach, such as swelling/deswelling of UF MSs and R6G diffusion within hydrophilic environment of UF MSs, are found to be of variable factors affecting the SERS performance. The substrate AgNP/UFMS confidently achieves a detection limit of 10(-13) M R6G and can be used as a simple and effective platform in the SERS spectroscopy.

  18. Interleukin-6 g.-174G>C promoter polymorphism is associated with obesity in the EPIC-Potsdam Study.

    PubMed

    Klipstein-Grobusch, Kerstin; Möhlig, Matthias; Spranger, Joachim; Hoffmann, Kurt; Rodrigues, Fabio U S; Sharma, Arya M; Klaus, Susanne; Pfeiffer, Andreas F H; Boeing, Heiner

    2006-01-01

    Homozygosity for the interleukin-6 (IL-6) g.-174G>C promoter polymorphism has recently been associated with indices of overweight. Homozygous subjects were observed to have reduced energy expenditure, suggesting that lower IL-6 gene transcription, caused by the IL-6 g.-174G>C promoter polymorphism, may be associated with obesity. The aim of this study was to investigate the association of this polymorphism with long-term weight gain. For 334 normal weight (20 < BMI < or = 25 kg/m2) and 334 obese (BMI > 30 kg/m2) subjects matched by age and sex originating from the population-based EPIC-Potsdam Study, recalled weight change from age 25 to study enrollment was determined, the IL-6 g.-174G>C promoter polymorphism was defined, and plasma concentrations of IL-6 and C-reactive protein were measured. The IL-6 g.-174G>C promoter polymorphism was significantly associated with obesity (chi2 = 7,34, p = 0.026). Odds ratios for subjects with GC and CC genotypes for obesity were 1.19 (95% CI: 0.84 to 1.68; p = 0.323) and 1.91 (95% CI: 1.19 to 3.08; p = 0.007), respectively. Recalled weight change from age 25 years to study enrollment differed significantly according to genotype (p = 0.044) and was most pronounced in subjects with the CC genotype, suggesting that the IL-6 g.-174G>C promoter polymorphism is a susceptibility or modifying locus for common obesity and weight gain.

  19. A Next Model of Northern Hemisphere Glaciation History: ICE-6G (VM5a)

    NASA Astrophysics Data System (ADS)

    Peltier, W. R.; Argus, D.; Gyllencreutz, R.; Mangerud, J.; Lohne, O. S.; Svendsen, J.

    2009-12-01

    Models of the evolving paleo-topography of the continents and paleo-bathymetry of the oceans, together with the evolving “masks” of the land-sea and surface albedo distributions, are required inputs for the application of modern coupled climate models in the reconstruction of past climate conditions. Previous reconstructions in the ICE-NG (VMX) sequence have relied almost exclusively upon ice-margin data sets to control the time dependence of the regions covered by glacial ice and the availability of radio-carbon dated relative sea level histories to control the evolution of continental ice-sheet thickness. In the past several years new space-geodetically derived data sets have become available that are allowing a further improvement in the accuracy of these reconstructions of environmental conditions over the period from Last Glacial Maximum to the beginning of the Holocene interglacial. These geodetic measurements include the time dependent gravitational field data being provided by the GRACE satellite system, as well as Very Long Baseline Interferometry (VLBI), Global Positioning System (GPS), Satellite Laser Ranging (SLR), and DORIS measurements of the present day rates of surface crustal displacement in both the vertical and horizontal directions.Furthermore, and in connection with our ability to understand the details of Eurasian deglaciation, a new model of ice-margin positions in this region has been produced that similarly impacts our understanding of glacial history throughout northwestern Europe. In this paper we will describe the revised model of northern hemisphere deglaciation that has enabled us to significantly improve upon the most recent ICE-5G (VM2) model that has continued to serve as the standard in this area since it was first published in 2004. The misfits if this model to the new space-geodetic data sets have recently been tabulated in Argus and Peltier (2009, GJI, submitted). Specific improvements to the previous model that will be the

  20. CRC handbook of laser science and technology. Volume 1. Lasers and masers

    SciTech Connect

    Weber, M.J.

    1982-01-01

    This book describes various types of lasers and masers. The following topics are discussed in detail: types and comparisons of laser sources, crystal and glass lasers, semiconductor lasers, organic dye and other liquid lasers, free-electron and x-ray lasers, masers and laser safety.

  1. IMB-6G, a novel N-substituted sophoridinic acid derivative, induces endoplasmic reticulum stress-mediated apoptosis via activation of IRE1α and PERK signaling

    PubMed Central

    Zhang, Na; Bi, Chongwen; Liu, Lu; Dou, Yueying; Tang, Sheng; Pang, Weiqiang; Deng, Hongbin; Song, Danqing

    2016-01-01

    Sophoridinic acid derivatives have received considerable attentions for their potencies in cancer therapy. IMB-6G is a novel N-substituted sophoridinic acid derivative with potent cytotoxicity against tumor cells. In the present study, we explored the antitumor abilities of IMB-6G in human hepatocellular carcinoma (HCC) cells and investigated the underlying mechanisms. We found that IMB-6G inhibited cell growth and induced mitochondrial-dependent apoptosis in HepG2 and SMMC7721 cells. Analyses of the molecular mechanism of IMB-6G-induced apoptosis indicated IMB-6G induced endoplasmic reticulum (ER) stress activation. Incubation of HCC cells with IMB-6G induced increase in Bip and CHOP levels, which precede induction of apoptosis. Further study showed IMB-6G activated IRE1α and PERK pathways but did not stimulated ATF6 pathway in HCC cells. Moreover, silencing of IRE1α dramatically abrogated IMB-6G-induced pro-apoptotic ASK1-JNK signaling. Importantly, interruption of CHOP rendered HCC cells sensitive to IMB-6G-induced apoptosis via inactivation of Bim, PUMA and Bax. Thus, the IRE1α-ASK1 and PERK-CHOP pathways may be a novel molecular mechanism of IMB-6G-induced apoptosis. Collectively, our study demonstrates that IMB-6G induces ER stress-mediated apoptosis by activating IRE1α and PERK pathways. Our findings provide a rationale for the potential application of IMB-6G in HCC therapy. PMID:27009865

  2. In vitro effectiveness of antimicrobial photodynamic therapy (APDT) using a 660 nm laser and malachite green dye in Staphylococcus aureus biofilms arranged on compact and cancellous bone specimens.

    PubMed

    Rosa, Luciano Pereira; da Silva, Francine Cristina; Nader, Sumaia Alves; Meira, Giselle Andrade; Viana, Magda Souza

    2014-11-01

    The aim of this study was to evaluate the in vitro effectiveness of antimicrobial photodynamic therapy (APDT) using a 660 nm visible laser combined with malachite green (MG) dye in the inactivation of Staphylococcus aureus (ATCC 25923) biofilms formed within compact and cancellous bone specimens. Specimens of 80 compact bones and 80 cancellous bones were contaminated with a standard suspension of S. aureus and incubated for 14 days at 37 °C to allow for the formation of biofilms. The specimens were divided into the following groups (n = 10) according to the treatment conditions: PS-L - (control - no treatment), PS+L - (only MG for 5 min), PS-L + 90 (only laser irradiation for 90 s), PS-L + 180 (only laser irradiation for 180 s), PS-L + 300 (only laser irradiation for 300 s), APDT90 (APDT for 90 s), APDT180 (APDT for 180 s), and APDT300 (APDT for 300 s). The findings were statistically analyzed using an ANOVA 5%. All of the experimental groups were significantly different from the control group for both the compact and cancellous bone specimens. The compact bone specimens that received APDT treatment (for either 90, 180, or 300 s) showed reductions in the log10 CFU/ml of S. aureus by a magnitude of 4 log10. Cancellous bone specimens treated with 300 s of APDT showed the highest efficacy, and these specimens had a reduction in S. aureus CFU/ml by a factor of 3 log10. APDT treatment using these proposed parameters in combination with MG was effective at inactivating S. aureus biofilms in compact and cancellous bone specimens.

  3. Stem cell marker upregulation in normal cutaneous vessels following pulsed-dye laser exposure and its abrogation by concurrent rapamycin administration: implications for treatment of port-wine stain birthmarks

    PubMed Central

    Loewe, Robert; Oble, Darryl A.; Valero, Teresa; Zukerberg, Lawrence; Mihm, Martin C.; Nelson, J. Stuart

    2011-01-01

    Port-wine stains (PWS) represent a group of vascular malformations that are usually accompanied by psychological distress for affected patients, often reflected in high treatment demand. Although the pulsed-dye laser (PDL) was established as standard therapy for PWS more than a decade ago, therapeutic outcome may be unsatisfactory. One of the main drawbacks to successful PDL therapy is PWS revascularization shortly after laser exposure. Therefore, inhibition of revascularization should improve therapeutic outcome of PDL therapy. In this study, we first evaluated the effects of various light energies on normal cutaneous vessels over a period of 14 days, particularly the proliferation and stem cell marker expression of dermal endothelial cells, which were found to be highest 8 days following laser exposure. We found that PDL exposure induced dose-dependent damage of dermal vessels up to energy densities of 6 J/cm2, above which no increase in PDL-induced effects were observed with the energies employed in this study. In dermal endothelial cells of PDL-exposed skin, we found strong expression of the proliferation marker Ki-67 as well as the stem cell marker nestin but not other stem cell markers such as CD133 and CD166. The influence of rapamycin (RPM), used as an adjuvant to PDL exposure, was also investigated. RPM administration reduced Ki-67 and nestin expression in dermal endothelial cells and increased PDL-induced destruction of dermal vessels, indicating that the use of RPM after PDL exposure may be an interesting new approach for prolonging and improving PWS laser therapeutic outcome. PMID:20482679

  4. Fluorescence properties of dye doped mesoporous silica

    SciTech Connect

    Carbonaro, Carlo M. Corpino, Riccardo Ricci, Pier Carlo Chiriu, Daniele; Cannas, Carla

    2014-10-21

    In this paper we present a review of the main results we obtained studying the emission properties of organic-inorganic hybrids obtained combining mesoporous silica and Xantene dyes, in particular the standard reference Rhodamine 6G. The purpose of the review is to show the possibility to efficiently 'dope' the transparent inorganic porous matrix to obtain promising systems for photonic and biomedical applications. The strategies to solve the concentration effect and the leaching phenomenon are discussed within the framework of the single exciton theory.

  5. Facile synthesis of gold nanopuncheons with high-index facets and their SERS effects on Rhodamine 6G

    SciTech Connect

    Li, Jing Chang, Minmin; Zhou, Xinmu; Li, Dongping; Li, Yongxiu

    2014-11-15

    Highlights: • Au nanopuncheons with high-index facets have been prepared by seed-mediated growth. • The nanopuncheons are enclosed by 24 planes of (2 5 0), (3 0 1) and 2 (0 1 0) planes. • The nanopuncheons showed high SERS activity toward Rhodamine 6G. - Abstract: Au nanopuncheons with exposed high-index facets have been synthesized in high-yield by employing didodecyldimethylammonium bromide (DDAB) as surfactant in one-step seed-mediated growth. Transmission electron microscopy (TEM) characterization showed that the as-prepared Au nanopuncheons possessed 24 high index facets of (2 5 0), (3 0 1), and 2 (0 1 0) planes. Due to the high density of atomic steps and kinks in the structure, the Au nanopuncheons exhibited high surface enhanced Raman scattering (SERS) activity toward Rhodamine 6G.

  6. Postglacial Rebound Model ICE-6G_C (VM5a) Constrained by Geodetic and Geologic Observations

    NASA Astrophysics Data System (ADS)

    Peltier, W. R.; Argus, D. F.; Drummond, R.

    2014-12-01

    We fit the revised global model of glacial isostatic adjustment ICE-6G_C (VM5a) to all available data, consisting of several hundred GPS uplift rates, a similar number of 14C dated relative sea level histories, and 62 geologic estimates of changes in Antarctic ice thickness. The mantle viscosity profile, VM5a is a simple multi-layer fit to prior model VM2 of Peltier (1996, Science). However, the revised deglaciation history, ICE-6G (VM5a), differs significantly from previous models in the Toronto series. (1) In North America, GPS observations of vertical uplift of Earth's surface from the Canadian Base Network require the thickness of the Laurentide ice sheet at Last Glacial Maximum to be significantly revised. At Last Glacial Maximum the new model ICE-6G_C in this region, relative to ICE-5G, roughly 50 percent thicker east of Hudson Bay (in and northern Quebec and Labrador region) and roughly 30 percent thinner west of Hudson Bay (in Manitoba, Saskatchewan, and the Northwest Territories).the net change in mass, however, is small. We find that rates of gravity change determined by GRACE when corrected for the predictions of ICE-6G_C (VM5a) are significantly smaller than residuals determined on the basis of earlier models. (2) In Antarctica, we fit GPS uplift rates, geologic estimates of changes in ice thickness, and geologic constraints on the timing of ice loss. The resulting deglaciation history also differs significantly from prior models. The contribution of Antarctic ice loss to global sea level rise since Last Glacial Maximum in ICE-6G_C is 13.6 meters, less than in ICE-5G (17.5 m), but significantly larger than in both the W12A model of Whitehouse et al. [2012] (8 m) and the IJ05 R02 model of Ivins et al. [2013] (7.5 m). In ICE-6G_C rapid ice loss occurs in Antarctica from 11.5 to 8 thousands years ago, with a rapid onset at 11.5 ka thereby contributing significantly to Meltwater Pulse 1B. In ICE-6G_C (VM5a), viscous uplift of Antarctica is increasing

  7. Cloth dye poisoning

    MedlinePlus

    ... poisonous ingredient in most household cloth dyes. Most common household cloth dyes are made from nonpoisonous substances, such as: Mild soaps Pigments Salts Although these substances are generally considered not dangerous, ...

  8. Advances in solid state laser technology for space and medical applications

    NASA Technical Reports Server (NTRS)

    Byvik, C. E.; Buoncristiani, A. M.

    1988-01-01

    Recent developments in laser technology and their potential for medical applications are discussed. Gas discharge lasers, dye lasers, excimer lasers, Nd:YAG lasers, HF and DF lasers, and other commonly used lasers are briefly addressed. Emerging laser technology is examined, including diode-pumped lasers and other solid state lasers.

  9. Rotational reorientation dynamics at high pressures: rhodamine 6G in ethanol from 1 bar to 6 kbar

    SciTech Connect

    Philips, L.A.; Webb, S.P.; Yeh, S.W.; Clark, J.H.

    1985-01-03

    Picosecond, time-resolved fluorescence depolarization spectroscopy has been used to measure the rotational reorientation time (tau/sub or/) of electronically excited rhodamine 6G. When the dependence of tau/sub or/ on solvent viscosity for a series of linear alcohols is compared with that for ethanol as a function of pressure over the range from 1 bar to 6 kbar, substantially different rotational reorientation dynamics are found for identical macroscopic viscosities. 31 references, 2 figures, 2 tables.

  10. Interleukin-6 G-174C gene polymorphism and serum resistin levels in North Indian women: potential risk of metabolic syndrome.

    PubMed

    Gupta, A; Gupta, V; Singh, A K; Tiwari, S; Agrawal, S; Natu, S M; Agrawal, C G; Negi, M P S; Pant, A B

    2011-10-01

    The present investigations were aimed to identify the possible association between genetic polymorphism in interleukin-6 (IL-6) G-174C gene, which confers susceptibility to metabolic syndrome, and serum level of resistin in North Indian women. The study population comprised 370 unrelated Indian women (192 having abdominal obesity and 178 controls). Polymorphism in genotype (CC+GC) of IL-6 G-174C gene was determined using a combination of polymerase chain reaction (PCR) and sequence-specific primer with restriction fragment length polymorphism (RFLP) technology. Insulin resistance (IR) and serum resistin level were also analyzed along with metabolic risk factors. Of 192 abdominal obese women, 147 (76.56%) were found to have mutant CC+GC (p = 0.001) genotype and allele frequency (p = 0.001), which was significantly higher 45 (23.44%) than non-obese and their respective wild type. The mutant genotype (CC+GC) of IL-6 gene was found to be associated significantly with high triglyceride (p = 0.025) and resistin level (p < 0.001), when compared with respective wild genotype (GG) in obese women. Non-obese women with no signs of metabolic risk factors were found to have significantly low level of serum resistin and IR in comparison to obese women having genetic polymorphism for IL-6 G-174C gene. Study suggests that IL-6 G-174C gene is one among the susceptibility loci for metabolic syndrome in North Indian women. Genotype for this polymorphism may prove informative for prediction of genetic risk for metabolic syndrome. Further, high level of serum resistin molecules may be targeted to correlate with metabolic syndrome risk factors and could be used as early prediction marker.

  11. Laser-frequency stabilization using forward scattering

    NASA Astrophysics Data System (ADS)

    Fellman, T.; Lindberg, Å.; Ståhlberg, B.

    1994-12-01

    Frequency stabilization of a single-mode dye laser is demonstrated using a simple magneto-optical forward scattering method. The dye laser was locked to the 2p4-3ss2, λ = 633 nm neon transition. Heterodyne beat-frequency measurements against a127I2-He-Ne meter standard laser showed a frequency stability of a few MHz.

  12. The laser in urology

    NASA Astrophysics Data System (ADS)

    Hofstetter, Alfons G.

    2002-10-01

    Laser is an acronym for a physical principle and means: Light Amplification by stimulated Emission of Radiation. This principle offers a lot of tissue/light effects caused by the parameters: power density/time and the special qualities of the laser light. Nowadays for diagnosis and therapy following lasers are used in urology: Krypton- and Dye-lasers as well as the Neodymium-YAG- (nd:YAG-), Holmium-YAG (Ho:YAG-), Diode-, Argon- and the CO2-lasers.

  13. Hydrothermal conversion of urban food waste to chars for removal of textile dyes from contaminated waters.

    PubMed

    Parshetti, Ganesh K; Chowdhury, Shamik; Balasubramanian, Rajasekhar

    2014-06-01

    Hydrothermal carbonization of urban food waste was carried out to prepare hydrochars for removal of Acridine Orange and Rhodamine 6G dyes from contaminated water. The chemical composition and microstructure properties of the synthesized hydrochars were investigated in details. Batch adsorption experiments revealed that hydrochars with lower degree of carbonization were more efficient in adsorption of dyes. Operational parameters such as pH and temperature had a strong influence on the dye uptake process. The adsorption equilibrium data showed excellent fit to the Langmuir isotherm. The pseudo-second-order kinetic model provided a better correlation for the experimental kinetic data in comparison to the pseudo-first-order kinetic model. Thermodynamic investigations suggested that dye adsorption onto hydrochars was spontaneous and endothermic. The mechanism of dye removal appears to be associated with physisorption. An artificial neural network (ANN)-based modelling was further carried out to predict the dye adsorption capacity of the hydrochars. PMID:24727353

  14. Physical and chemical investigations on natural dyes

    NASA Astrophysics Data System (ADS)

    Acquaviva, S.; D'Anna, E.; de Giorgi, M. L.; Della Patria, A.; Baraldi, P.

    2010-09-01

    Natural dyes have been used extensively in the past for many purposes, such us to colour fibers and to produce inks, watercolours and paints, but their use declined rapidly after the discovery of synthetic colours. Nowadays we witness a renewed interest, as natural dyes are neither toxic nor polluting. In this work, physical and chemical properties of four selected dyes, namely red (Madder), yellow (Weld and Turmeric) and blue (Woad) colours, produced by means of traditional techniques at the Museo dei Colori Naturali (Lamoli, Italy), have been investigated. The chromatic properties have been studied through the reflectance spectroscopy, a non-invasive technique for the characterisation of chromaticity. Reflection spectra both from powders and egg-yolk tempera models have been acquired to provide the typical features of the dyes in the UV-vis spectral range. Moreover, to assess the feasibility of laser cleaning procedures, tempera layers were investigated after irradiation with an excimer laser. Micro Raman spectroscopy, Scanning Electron Microscopy and Energy Dispersive X-Ray analyses have complemented the survey, returning compositional and morphological information as well. Efforts have been made to give scientific feedback to the production processes and to support the research activity in the restoration of the artworks where these dyes were employed.

  15. Matrix-assisted laser desorption/ionization mass spectrometric analysis of poly(3,4-ethylenedioxythiophene) in solid-state dye-sensitized solar cells: comparison of in situ photoelectrochemical polymerization in aqueous micellar and organic media.

    PubMed

    Zhang, Jinbao; Ellis, Hanna; Yang, Lei; Johansson, Erik M J; Boschloo, Gerrit; Vlachopoulos, Nick; Hagfeldt, Anders; Bergquist, Jonas; Shevchenko, Denys

    2015-04-01

    Solid-state dye-sensitized solar cells (sDSCs) are devoid of such issues as electrolyte evaporation or leakage and electrode corrosion, which are typical for traditional liquid electrolyte-based DSCs. Poly(3,4-ethylenedioxythiophene) (PEDOT) is one of the most popular and efficient p-type conducting polymers that are used in sDSCs as a solid-state hole-transporting material. The most convenient way to deposit this insoluble polymer into the dye-sensitized mesoporous working electrode is in situ photoelectrochemical polymerization. Apparently, the structure and the physicochemical properties of the generated conducting polymer, which determine the photovoltaic performance of the corresponding solar cell, can be significantly affected by the preparation conditions. Therefore, a simple and fast analytical method that can reveal information on polymer chain length, possible chemical modifications, and impurities is strongly required for the rapid development of efficient solar energy-converting devices. In this contribution, we applied matrix-assisted laser desorption/ionization mass spectrometry (MALDI MS) for the analysis of PEDOT directly on sDSCs. It was found that the PEDOT generated in aqueous micellar medium possesses relatively shorter polymeric chains than the PEDOT deposited from an organic medium. Furthermore, the micellar electrolyte promotes a transformation of one of the thiophene terminal units to thiophenone. The introduction of a carbonyl group into the PEDOT molecule impedes the growth of the polymer chain and reduces the conductivity of the final polymer film. Both the simplicity of sample preparation (only application of the organic matrix onto the solar cell is needed) and the rapidity of analysis hold the promise of making MALDI MS an essential tool for the physicochemical characterization of conducting polymer-based sDSCs.

  16. Catalytic solid substrate-room temperature phosphorimetry for the determination of residual perphenazine based on the electronic effect of rhodamine 6G.

    PubMed

    Zheng, Zhi-Yong; Cui, Ma-Lin; Zhang, Li-Hong; Jiang, Shu-Lian; Jiao, Li; Lin, Xuan; Lin, Shao-Qin; Liu, Jia-Ming

    2013-01-01

    The rhodamine 6G(+) -perphenazine (Rhod 6G(+) -PPH) compound is formed in the ester-exchange reaction between -OH of PPH and -COOC2 H5 of Rhod 6G(+) . PPH was oxidized to a red compound (PPH') in the presence of K2 S2 O8 . Interestingly, the room temperature phosphorescence (RTP) of Rhod 6G(+) was quenched because the -OH of PPH' reacted with -COOC2 H5 of Rhod 6G(+) -PPH to form Rhod 6G(+) -PPH' and PPH, which decreased the π-electron density (δ) of the carbon atom in the Rhod 6G(+) -PPH' conjugated system and enhanced the nonradiation energy loss of the excited Rhod 6G(+) of the triplet state. The PPH content was directly proportional to the ΔIp of the system. Thus, a new catalytic solid-substrate room temperature phosphorimetry (SSRTP) method was established for the determination of PPH. The method had high sensitivity (the limit of detection was 0.019 fg/spot, corresponding to a concentration of 4.8 × 10(-14)  g/mL; the sampling quantity was 0.40 μL/spot), good selectivity, convenience and speed. The analytical results were in accordance with those of high-performance liquid chromatography (HPLC). The structures of Rhod 6G(+) , PPH and Rhod 6G(+) -PPH were characterized by infrared spectra. The reaction mechanism by which PPH was determined is discussed.

  17. Ultrasonic dyeing of cellulose nanofibers.

    PubMed

    Khatri, Muzamil; Ahmed, Farooq; Jatoi, Abdul Wahab; Mahar, Rasool Bux; Khatri, Zeeshan; Kim, Ick Soo

    2016-07-01

    Textile dyeing assisted by ultrasonic energy has attained a greater interest in recent years. We report ultrasonic dyeing of nanofibers for the very first time. We chose cellulose nanofibers and dyed with two reactive dyes, CI reactive black 5 and CI reactive red 195. The cellulose nanofibers were prepared by electrospinning of cellulose acetate (CA) followed by deacetylation. The FTIR results confirmed complete conversion of CA into cellulose nanofibers. Dyeing parameters optimized were dyeing temperature, dyeing time and dye concentrations for each class of the dye used. Results revealed that the ultrasonic dyeing produced higher color yield (K/S values) than the conventional dyeing. The color fastness test results depicted good dye fixation. SEM analysis evidenced that ultrasonic energy during dyeing do not affect surface morphology of nanofibers. The results conclude successful dyeing of cellulose nanofibers using ultrasonic energy with better color yield and color fastness results than conventional dyeing. PMID:26964959

  18. Ultrasonic dyeing of cellulose nanofibers.

    PubMed

    Khatri, Muzamil; Ahmed, Farooq; Jatoi, Abdul Wahab; Mahar, Rasool Bux; Khatri, Zeeshan; Kim, Ick Soo

    2016-07-01

    Textile dyeing assisted by ultrasonic energy has attained a greater interest in recent years. We report ultrasonic dyeing of nanofibers for the very first time. We chose cellulose nanofibers and dyed with two reactive dyes, CI reactive black 5 and CI reactive red 195. The cellulose nanofibers were prepared by electrospinning of cellulose acetate (CA) followed by deacetylation. The FTIR results confirmed complete conversion of CA into cellulose nanofibers. Dyeing parameters optimized were dyeing temperature, dyeing time and dye concentrations for each class of the dye used. Results revealed that the ultrasonic dyeing produced higher color yield (K/S values) than the conventional dyeing. The color fastness test results depicted good dye fixation. SEM analysis evidenced that ultrasonic energy during dyeing do not affect surface morphology of nanofibers. The results conclude successful dyeing of cellulose nanofibers using ultrasonic energy with better color yield and color fastness results than conventional dyeing.

  19. Synthesis, linear optical, non-linear optical, thermal and mechanical characterizations of dye-doped semi-organic NLO crystals

    NASA Astrophysics Data System (ADS)

    Sesha Bamini, N.; Vidyalakshmy, Y.; Choedak, Tenzin; Kejalakshmy, N.; Muthukrishnan, P.; Ancy, C. J.

    2015-06-01

    Organic laser dyes Coumarin 485, Coumarin 540 and Rhodamine 590 Chloride were used to dope potassium acid phthalate crystals (KAP). Dye-doped KAP crystals with different dye concentrations such as 0.01 mM, 0.03 mM, 0.05 mM, 0.07 mM and 0.09 mM (in the KAP growth solution) were grown. The linear optical, non-linear optical, mechanical and thermal characterizations of dye-doped KAP crystals were studied and compared to understand the effect of dye and dye concentration on the KAP crystal. Absorption and emission studies of KAP and dye-doped KAP single crystals indicated the inclusion of the dye into the KAP crystal lattice. The effect of dye and its concentration on the SHG efficiency of the KAP crystal was studied using the Kurtz and Perry powder technique. It was observed that the absorption maximum wavelength and concentration of the dye used for doping the KAP single crystal decided the SHG efficiency of the dye-doped KAP single crystals. The mechanical hardness of the dye-doped and undoped (pure) KAP single crystals were studied using the Vickner’s microhardness test. It was observed that doping the KAP crystals with the laser dyes changed them from softer material to harder material. Etching studies showed an improvement in the optical quality of the KAP crystal after doping with laser dyes.

  20. Phototoxic effect of conjugates of plasmon-resonance nanoparticles with indocyanine green dye on Staphylococcus aureus induced by IR laser radiation

    SciTech Connect

    Tuchina, E S; Tuchin, Valerii V; Khlebtsov, B N; Khlebtsov, Nikolai G

    2011-04-30

    The effect of IR laser radiation ({lambda} = 805 - 808 nm) on the bacteria of the strain Staphylococcus aureus 209 P, incubated in indocyanine green solutions, is studied, as well as that of colloid gold nanoshells, nanocages and their conjugates with indocyanine green. It is found that the S. aureus 209 P cells are equally subjected to the IR laser radiation ({lambda} = 805 nm) after preliminary sensitisation with indocyanine green and gold nanoparticles separately and with conjugates of nanoparticles and indocyanine green. The enhancement of photodynamic and photothermal effects by 5 % is observed after 30 min of laser illumination ({lambda} = 808 nm) of bacteria, treated with conjugates of indocyanine green and nanocages. (optical technologies in biophysics and medicine)

  1. Interactions of dissolved humic substances with oppositely charged fluorescent dyes for tracer techniques.

    PubMed

    Hafuka, Akira; Ding, Qing; Yamamura, Hiroshi; Yamada, Koji; Satoh, Hisashi

    2015-11-15

    To investigate interactions between oppositely charged fluorescent dyes and dissolved humic substances, fluorescence quenching of fluorescein and rhodamine 6G with dissolved humic substances was performed. Binding coefficients were obtained by the Stern-Volmer equation. The fluorescence of rhodamine 6G was largely quenched by the addition of humic acid and a non-linear Stern-Volmer plot was obtained. This strong quenching may be caused by the electrostatic interaction between cationic rhodamine 6G and humic acid and strengthened by the hydrophobic repulsion. In contrast, the quenching and interactive effects of dissolved humic substances for fluorescein were relatively weak. PMID:26318652

  2. Exploring the Application of the Negishi Reaction of HaloBODIPYs: Generality, Regioselectivity, and Synthetic Utility in the Development of BODIPY Laser Dyes.

    PubMed

    Palao, Eduardo; Duran-Sampedro, Gonzalo; de la Moya, Santiago; Madrid, Miriam; García-López, Carmen; Agarrabeitia, Antonia R; Verbelen, Bram; Dehaen, Wim; Boens, Nöel; Ortiz, María J

    2016-05-01

    The generality of the palladium-catalyzed C-C coupling Negishi reaction when applied to haloBODIPYs is demonstrated on the basis of selected starting BODIPYs, including polyhalogenated and/or asymmetrical systems, and organozinc reagents. This reaction is an interesting synthetic tool in BODIPY chemistry, mainly because it allows a valuable regioselective postfunctionalization of BODIPY chromophores with different functional groups. In this way, functional patterns that are difficult to obtain by other procedures (e.g., asymmetrically functionalized BODIPYs involving halogenated positions) can now be made. The regioselectivity is achieved by controlling the reaction conditions and is based on almost-general reactivity preferences, and the nature of the involved halogens and their positions. This ability is exemplified by the preparation of a series of new BODIPY dyes with unprecedented substitution patterns allowing noticeable lasing properties. PMID:27055068

  3. Novel PAMAM Dendron as a Bichromophoric Probe Based on Rhodamine 6G and 1,8-Naphthalimide.

    PubMed

    Dimitrova, Margarita D; Georgiev, Nikolai I; Bojinov, Vladimir B

    2016-05-01

    A novel PAMAM dendron designed as a wavelength-shifting bichromophore with 1,8-naphthalimide energy "donor" capable of absorbing light and efficiently transferring the energy to a focal Rhodamine 6G "acceptor" was synthesized and investigated. Moreover, the system was configured on the "fluorophore-spacer-receptor" format. Thus, the distinguishing features of FRET systems were successfully combined with the properties of photoinduced electron transfer and classical ring-opening sensor systems. The synthesized compound shows excellent signaling properties towards protons, Hg(2+) and Fe(3+) ions, therefore, the system is able to act as an one-output combinatorial logic circuit with four chemical inputs. PMID:27048224

  4. Rhodamine 6G hydrazone bearing thiophene unit: A highly sensitive and selective off-on fluorescent chemosensor for Al3+

    NASA Astrophysics Data System (ADS)

    Wu, Wei-Na; Mao, Pan-Dong; Wang, Yuan; Zhao, Xiao-Lei; Jia, Lei; Xu, Zhou-Qing

    2016-10-01

    A rhodamine derivative (R1) has been synthesized by a hydrazone formation of rhodamine 6G hydrazide with 3-methylthiophene-2-carbaldehyde, which exhibits high selectivity and sensitivity as an "off-on" fluorescent sensor toward Al3+ in water containing media. The binding process was confirmed by UV-vis absorption, fluorescence measurements, mass spectroscopy and DFT calculation. The probe functions by Al3+ induced hydrolytic cleavage of the imine-bond to produce an intense rhodamine-based emission. To test the practical use of the probe, the determination of Al3+ in real water samples was also evaluated.

  5. Par6G suppresses cell proliferation and is targeted by loss-of-function mutations in multiple cancers

    PubMed Central

    Marques, E; Englund, J I; Tervonen, T A; Virkunen, E; Laakso, M; Myllynen, M; Mäkelä, A; Ahvenainen, M; Lepikhova, T; Monni, O; Hautaniemi, S; Klefström, J

    2016-01-01

    Differentiated epithelial structure communicates with individual constituent epithelial cells to suppress their proliferation activity. However, the pathways linking epithelial structure to cessation of the cell proliferation machinery or to unscheduled proliferation in the context of tumorigenesis are not well defined. Here we demonstrate the strong impact of compromised epithelial integrity on normal and oncogenic Myc-driven proliferation in three-dimensional mammary epithelial organoid culture. Systematic silencing of 34 human homologs of Drosophila genes, with previously established functions in control of epithelial integrity, demonstrates a role for human genes of apico-basal polarity, Wnt and Hippo pathways and actin dynamics in regulation of the size, integrity and cell proliferation in organoids. Perturbation of these pathways leads to diverse functional interactions with Myc: manifested as a RhoA-dependent synthetic lethality and Par6-dependent effects on the cell cycle. Furthermore, we show a role for Par6G as a negative regulator of the phosphatidylinositol 3′-kinase/phosphoinositide-dependent protein kinase 1/Akt pathway and epithelial cell proliferation and evidence for frequent inactivation of Par6G gene in epithelial cancers. The findings demonstrate that determinants of epithelial structure regulate the cell proliferation activity via conserved and cancer-relevant regulatory circuitries, which are important for epithelial cell cycle restriction and may provide new targets for therapeutic intervention. PMID:26073086

  6. Styryl dye coated metal oxide powders for the detection of latent fingermarks on non-porous surfaces.

    PubMed

    Chadwick, Scott; Maynard, Philip; Kirkbride, Paul; Lennard, Chris; McDonagh, Andrew; Spindler, Xanthe; Roux, Claude

    2012-06-10

    Conventional fingermark powders rely on contrast induced by absorption/reflection (e.g. black powder) or luminescence in the visible region (e.g. Blitz Green(®)). In most cases, these powders provide sufficient contrast; however, in some circumstances surface characteristics can interfere with the visualisation of powdered fingermarks. Visualisation in the near infra-red (NIR) region, however, has been shown to eliminate interferences commonly encountered in the visible region. In this study, a mixture of rhodamine 6G and the NIR laser dye styryl 11 (STaR 11) was coated onto an aluminium oxide nanopowder and then mixed with silver magnetic powder to develop and visualise fingermarks in the NIR. When compared to Blitz Green(®), it was determined that the STaR 11 magnetic powder was better suited for marks deposited on textured surfaces and for older marks, whereas Blitz Green(®) performed better on smooth glossy surfaces. The ability of the STaR 11 mixed dye formulation to be visualised in both the visible and NIR regions also provides a significant advantage over conventional luminescent fingermark powders.

  7. [Lasers].

    PubMed

    Passeron, T

    2012-11-01

    Lasers are a very effective approach for treating many hyperpigmented lesions. They are the gold standard treatment for actinic lentigos and dermal hypermelanocytosis, such as Ota nevus. Becker nevus, hyperpigmented mosaicisms, and lentigines can also be successfully treated with lasers, but they could be less effective and relapses can be observed. However, lasers cannot be proposed for all types of hyperpigmentation. Thus, freckles and café-au-lait macules should not be treated as the relapses are nearly constant. Due to its complex pathophysiology, melasma has a special place in hyperpigmented dermatoses. Q-switched lasers (using standard parameters or low fluency) should not be used because of consistent relapses and the high risk of post-inflammatory hyperpigmentation. Paradoxically, targeting the vascular component of the melasma lesion with lasers could have a beneficial effect. However, these results have yet to be confirmed. In all cases, a precise diagnosis of the type of hyperpigmentation is mandatory before any laser treatment, and the limits and the potential side effects of the treatment must be clearly explained to patients.

  8. Lasers.

    PubMed

    Passeron, T

    2012-12-01

    Lasers are a very effective approach for treating many hyperpigmented lesions. They are the gold standard treatment for actinic lentigos and dermal hypermelanocytosis, such as Ota nevus. Becker nevus, hyperpigmented mosaicisms, and lentigines can also be successfully treated with lasers, but they could be less effective and relapses can be observed. However, lasers cannot be proposed for all types of hyperpigmentation. Thus, freckles and café-au-lait macules should not be treated as the relapses are nearly constant. Due to its complex pathophysiology, melasma has a special place in hyperpigmented dermatoses. Q-switched lasers (using standard parameters or low fluency) should not be used because of consistent relapses and the high risk of post-inflammatory hyperpigmentation. Paradoxically, targeting the vascular component of the melasma lesion with lasers could have a beneficial effect. However, these results have yet to be confirmed. In all cases, a precise diagnosis of the type of hyperpigmentation is mandatory before any laser treatment, and the limits and the potential side effects of the treatment must be clearly explained to patients.

  9. Synthesis of Ag-doped TiO2 nanoparticles by combining laser decomposition of titanium isopropoxide and ablation of Ag for dye-sensitized solar cells

    NASA Astrophysics Data System (ADS)

    Al-Kamal, Ahmed Kamal

    Nanostructured powders of TiO2 and Ag-doped TiO2 are synthesized by a novel pulsed-laser process that combines laser ablation of a silver (Ag) disc with laser decomposition of a titanium tetra-isopropoxide (TTIP) solution. Nanoparticles are formed by rapid condensation of vaporized species in the plasma plume generated by the high power laser, resulting in the formation of rapidly quenched Ag-doped TiO2 nanoparticles that have far-from-equilibrium or metastable structures. The uniqueness of the new ablation process is that it is a one-step process, in contrast to the two-step process developed by previous researchers in the field. Moreover, its ability to synthesize an extended-solid solution phase of Ag in TiO 2 may also be unique. The present work implies that other oxide phases, such as Al2O3, MgO and MgAl2O4, can be doped with normally insoluble metals, such as Pt and Ir, thus opening new opportunities for catalytic applications. Again, there is the prospect of being able to synthesize nanopowders of diamond, c-BN, and mixtures thereof, which are of interest for applications in machine tools, rock-drill bits, and lightweight armor. A wet-chemistry method is also investigated, which has much in common with that adopted by previous workers in the field. However, photo-voltaic properties do not measure up to expectations based on published data. A possible explanation is that the selected Ag concentrations are too high, so that recombination of holes and electrons occurs via a quantum-tunneling mechanism reduces photo-activity. Future work, therefore, will investigate lower concentrations of Ag dopant in TiO2, while also examining the effects of metastable states, including extended solid solution, amorphous, and semi-crystalline structures.

  10. Nonlinear optical properties of multipyrrole dyes

    PubMed Central

    Frenette, Mathieu; Hatamimoslehabadi, Maryam; Bellinger-Buckley, Stephanie; Laoui, Samir; Bag, Seema; Dantiste, Olivier; Rochford, Jonathan; Yelleswarapu, Chandra

    2014-01-01

    The nonlinear optical properties of a series of pyrrolic compounds consisting of BODIPY and aza-BODIPY systems are investigated using 532 nm nanosecond laser and the Z-scan technique. Results show that 3,5-distyryl extension of BODIPY to the red shifted MeO2BODIPY dye has a dramatic impact on its nonlinear absorption properties changing it from a saturable absorber to an efficient reverse saturable absorbing material with a nonlinear absorption coefficient of 4.64 × 10−10 m/W. When plotted on a concentration scale per mole of dye in solution MeO2BODIPY far outperforms the recognized zinc(II) phthalocyanine dye and is comparable to that of zinc(II) tetraphenylporphyrin. PMID:25242819

  11. Lidar: A laser technique for remote sensing

    NASA Technical Reports Server (NTRS)

    Wilkerson, T. D.; Hickman, G. D.

    1978-01-01

    Experimental airborne lidar systems proved to be useful for shallow water bathymetric measurements, and detection and identification of oil slicks and algae. Dye fluorescence applications using organic dyes was studied. The possibility of remotely inducing dye flourescence by means of pulsed lasers opens up several hydrospheric applications for measuring water currents, water temperature, and salinity. Aerosol measurements by lidar are also discussed.

  12. Combining Laser Ablation/Liquid Phase Collection Surface Sampling and High-Performance Liquid Chromatography Electrospray Ionization Mass Spectrometry

    SciTech Connect

    Ovchinnikova, Olga S; Kertesz, Vilmos; Van Berkel, Gary J

    2011-01-01

    This paper describes the coupling of ambient pressure transmission geometry laser ablation with a liquid phase sample collection method for surface sampling and ionization with subsequent mass spectral analysis. A commercially available autosampler was adapted to produce a liquid droplet at the end of the syringe injection needle while in close proximity to the surface to collect the sample plume produced by laser ablation. The sample collection was followed by either flow injection or a high performance liquid chromatography (HPLC) separation of the extracted components and detection with electrospray ionization mass spectrometry (ESI-MS). To illustrate the analytical utility of this coupling, thin films of a commercial ink sample containing rhodamine 6G and of mixed isobaric rhodamine B and 6G dyes on glass microscope slides were analyzed. The flow injection and HPLC/ESI-MS analysis revealed successful laser ablation, capture and, with HPLC, the separation of the two compounds. The ablated circular area was about 70 m in diameter for these experiments. The spatial sampling resolution afforded by the laser ablation, as well as the ability to use sample processing methods like HPLC between the sample collection and ionization steps, makes this combined surface sampling/ionization technique a highly versatile analytical tool.

  13. SERS detection of R6G based on a novel graphene oxide/silver nanoparticles/silicon pyramid arrays structure.

    PubMed

    Zhang, C; Jiang, S Z; Huo, Y Y; Liu, A H; Xu, S C; Liu, X Y; Sun, Z C; Xu, Y Y; Li, Z; Man, B Y

    2015-09-21

    We present a novel surface-enhanced Raman scattering (SERS) substrate based on graphene oxide/silver nanoparticles/silicon pyramid arrays structure (GO/Ag/PSi). The SERS behaviors are discussed and compared by the detection of R6G. Based on the contrast experiments with PSi, GO/PSi, Ag/PSi and GO/AgA/PSi as SERS substrate, the perfect bio-compatibility, good homogeneity and chemical stability were confirmed. We also calculated the electric field distributions using Finite-difference time-domain (FDTD) analysis to further understand the GO/Ag/PSi structure as a perfect SERS platform. These experimental and theoretical results imply that the GO/Ag/PSi with regular pyramids array is expected to be an effective substrate for label-free sensitive SERS detections in areas of medicine, food safety and biotechnology.

  14. Space geodesy constrains ice age terminal deglaciation: The global ICE-6G_C (VM5a) model

    NASA Astrophysics Data System (ADS)

    Peltier, W. R.; Argus, D. F.; Drummond, R.

    2015-01-01

    A new model of the last deglaciation event of the Late Quaternary ice age is here described and denoted as ICE-6G_C (VM5a). It differs from previously published models in this sequence in that it has been explicitly refined by applying all of the available Global Positioning System (GPS) measurements of vertical motion of the crust that may be brought to bear to constrain the thickness of local ice cover as well as the timing of its removal. Additional space geodetic constraints have also been applied to specify the reference frame within which the GPS data are described. The focus of the paper is upon the three main regions of Last Glacial Maximum ice cover, namely, North America, Northwestern Europe/Eurasia, and Antarctica, although Greenland and the British Isles will also be included, if peripherally, in the discussion. In each of the three major regions, the model predictions of the time rate of change of the gravitational field are also compared to that being measured by the Gravity Recovery and Climate Experiment satellites as an independent means of verifying the improvement of the model achieved by applying the GPS constraints. Several aspects of the global characteristics of this new model are also discussed, including the nature of relative sea level history predictions at far-field locations, in particular the Caribbean island of Barbados, from which especially high-quality records of postglacial sea level change are available but which records were not employed in the development of the model. Although ICE-6G_C (VM5a) is a significant improvement insofar as the most recently available GPS observations are concerned, comparison of model predictions with such far-field relative sea level histories enables us to identify a series of additional improvements that should follow from a further stage of model iteration.

  15. Accurate and absolute diffusion measurements of Rhodamine 6G in low-concentration aqueous solutions by the PGSE-WATERGATE sequence

    SciTech Connect

    Majer, G.; Zick, K.

    2015-04-28

    A pulsed field gradient spin-echo nuclear magnetic resonance (NMR) sequence with solvent suppression (PGSE-WATERGATE) was applied to accurately measure the diffusion coefficients of Rhodamine 6G (Rh6G) in low-concentration aqueous solutions. Three samples with Rh6G concentrations of C{sub Rh6G} = 1, 4.5, and 25 μM were investigated. The precise determination of the diffusion coefficients in this low-concentration range was made possible by using a cryogenically cooled NMR probe and by the effective solvent suppression of the PGSE-WATERGATE sequence. The present results bridge the gap between diffusion data measured by fluorescence correlation spectroscopy in the single molecule limit and diffusivities obtained by pulsed field gradient NMR (PFG-NMR) without solvent suppression at higher concentrations. To further extend the concentration range, the diffusion coefficient of Rh6G was also measured on a sample with C{sub Rh6G} = 410 μM by PFG-NMR. The overall concentration dependence of the Rh6G diffusion at 25 °C is discussed in terms of dimerization of the Rh6G molecules. The concentration-dependent monomer/dimer proportion is deduced from the diffusion data.

  16. Laser Detection Of Latent Fingerprints: Tris(2,2'-Bipyridyl)Ruthenium(II) Chloride Hexahydrate As A Staining Dye For Time-Resolved Imaging

    NASA Astrophysics Data System (ADS)

    Menzel, E. R.

    1988-04-01

    The compound tris(2,2'-bipyridyl)ruthenium(II) chloride hexahydrate is suitable for laser detection of latent fingerprints on difficult surfaces such as wood and masking tape, as well as surfaces such as polyethylene, metal, etc. The fingerprint treatment can Involve either dusting with powder blended with this compound or by solution staining. The compound displays a strong d-n phosphorescence with a lifetime of about 10-6 and is thus very well suited for time-resolved imaging to suppress background fluorescence.

  17. Dependence of the activation energy of rhodamine 6G phototransformation into an irreversible photoproduct on the excitation wavelength

    SciTech Connect

    Aristov, A.V.

    1994-12-01

    The results of our previous studies of the quantum yield {Phi}{sub ip} of irreversible phototransformations in rhodamines in deoxygenated solutions are presented along with the results of a quantum-chemical analysis of the dipole-dipole electronic transitions between different molecular orbitals in the 15000-38000 cm{sup -1} spectral region. A combined analysis of these results gives insight into the features of the singlet-singlet absorption spectrum of xanthene dyes in a broad spectral region from 15000 to 38000 cm{sup -1} and explains a considerable difference in values of {Phi}{sub ip} upon excitations into the isoenergetic states in different parts of the absorption spectrum. The relation between the threshold activation energy of the photodestruction of molecules and molecular orbitals involved in the electronic transitions induced by absorption of photons in different spectral regions is found. 10 refs., 1 fig.

  18. PVA with nopal dye as holographic recording material

    NASA Astrophysics Data System (ADS)

    Toxqui-López, S.; Olivares-Pérez, A.; Fuentes-Tapia, I.; Pinto-Iguanero, B.

    2011-09-01

    Cactus nopal dye is introduced into a polyvinyl alcohol matrix achieving a like brown appearance thick film, such that they can be used as a recording medium. This dye material provides excellent property as photosensitizer, i.e., easy handling, low cost and can be used in real time holographic recording applications. The experimental results show the diffraction efficiencies obtained by recording grating patterns induced by a He-Cd laser (442nm). For the samples, a thick film of polyvinyl alcohol and dye from cactus nopal was deposited by the gravity technique on a glass substrate. This mixture dries to form a photosensitive emulsion.

  19. Diffusion of dye solution in the intermolecular nanostructure of polydimethylsiloxane

    NASA Astrophysics Data System (ADS)

    Saito, Mitsunori; Nishimura, Tatsuya; Sakiyama, Kohei; Nakagawa, Michinori

    2012-09-01

    Polydimethylsiloxane (PDMS) contains a large, flexible free space between weakly-bonded molecules, which allows notable molecular diffusion. A toluene solution of diarylethene (photochromic dye) was mixed with a PDMS oil, and then the mixture was cured in a glass vessel by adding a curing agent. Violet laser (405 nm wavelength) irradiation induced an absorption band at around 530 nm, and consequently, the irradiated portion exhibited a red color. The colored portion gradually expanded to the entire sample because of diffusion of the dye molecules. This diffusion characteristic was used for improving an organic dye durability against a photo-induced degradation.

  20. Optofluidic laser array based on stable high-Q Fabry-Pérot microcavities.

    PubMed

    Wang, Wenjie; Zhou, Chunhua; Zhang, Tingting; Chen, Jingdong; Liu, Shaoding; Fan, Xudong

    2015-10-01

    We report the development of an optofluidic laser array fabricated on a chip using stable plano-concave Fabry-Pérot (FP) microcavities, which are far less susceptible to optical misalignment during device assembly than the commonly used plano-plano FP microcavities. The concave mirrors in our FP microcavities were created by first generating an array of microwells of a few micrometers in depth and a few tens of micrometers in diameter on a fused silica chip using a CO2 laser, followed by coating of distributed Bragg reflection (DBR) layers. The plano-concave FP microcavity had a Q-factor of 5.6 × 10(5) and finesse of 4 × 10(3), over 100 times higher than those for the FP microcavities in existing optofluidic lasers. 1 mM R6G dye in ethanol was used to test the plano-concave FP microcavities, showing an ultralow lasing threshold of only 90 nJ mm(-2), over 10 times lower than that in the corresponding unstable plano-plano FP microcavities formed by the same DBR coatings on the same chip. Simultaneous laser emission from the optofluidic laser array on the chip and single-mode lasing operation were also demonstrated. Our work will lead to the development of optofluidic laser-based biochemical sensors and novel on-chip photonic devices with extremely low lasing thresholds (nJ mm(-2)) and mode volumes (fL).