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Sample records for dye lasers

  1. Dye laser amplifier

    DOEpatents

    Moses, E.I.

    1992-12-01

    An improved dye laser amplifier is disclosed. The efficiency of the dye laser amplifier is increased significantly by increasing the power of a dye beam as it passes from an input window to an output window within the dye chamber, while maintaining the intensity of the dye beam constant. 3 figs.

  2. Dye laser amplifier

    DOEpatents

    Moses, Edward I.

    1992-01-01

    An improved dye laser amplifier is disclosed. The efficiency of the dye lr amplifier is increased significantly by increasing the power of a dye beam as it passes from an input window to an output window within the dye chamber, while maintaining the intensity of the dye beam constant.

  3. Laser dye stability

    NASA Astrophysics Data System (ADS)

    Fletcher, N.

    1980-06-01

    Lasing characteristics and bleaching of four Eastman Kodak ir dyes have been examined in dimethyl sulfoxide. These ir dyes are shown to improve in performance in the absence of oxygen. Their photochemical stability was found to be comparable to the quinolone laser dyes when exposed to flashlamp excitation. Photodecomposition of the ir dyes under lasing conditions was found to vary between 1.6 and 6×10-10 moles of dye for each joule (electrical) of input energy; in comparison, the photodecomposition values for the better coumarin dyes was 0.2 to 1.0×10-10 moles/J at a concentration of 1.0×10-4 M in ethanol. It was also found that increasing the concentration of these tricarbocyanine dyes gives a marked improvement in the useful lifetime of these solutions as lasing media in the absence of oxygen.

  4. 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##

  5. 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.

  6. Monolithic dye laser amplifier

    DOEpatents

    Kuklo, Thomas C.

    1993-01-01

    A fluid dye laser amplifier for amplifying a dye beam by pump beams has a channel structure defining a channel through which a laseable fluid flows and the dye and pump beams pass transversely to one another through a lasing region. The channel structure is formed with two pairs of mutually spaced-apart and mutually confronting glass windows, which are interlocked and make surface-contacts with one another and surround the lasing region. One of the glass window pairs passes the dye beam and the other passes the pump beams therethrough and through the lasing region. Where these glass window pieces make surface-contacts, glue is used to join the pieces together to form a monolithic structure so as to prevent the dye in the fluid passing through the channel from entering the space between the mutually contacting glass window pieces.

  7. Monolithic dye laser amplifier

    DOEpatents

    Kuklo, T.C.

    1993-03-30

    A fluid dye laser amplifier for amplifying a dye beam by pump beams has a channel structure defining a channel through which a laseable fluid flows and the dye and pump beams pass transversely to one another through a lasing region. The channel structure is formed with two pairs of mutually spaced-apart and mutually confronting glass windows, which are interlocked and make surface-contacts with one another and surround the lasing region. One of the glass window pairs passes the dye beam and the other passes the pump beams therethrough and through the lasing region. Where these glass window pieces make surface-contacts, glue is used to join the pieces together to form a monolithic structure so as to prevent the dye in the fluid passing through the channel from entering the space between the mutually contacting glass window pieces.

  8. Chemical stabilization of laser dyes

    NASA Astrophysics Data System (ADS)

    Koch, Tad H.

    1987-05-01

    Coumarin laser dyes upon excitation degrade to produce products which absorb at the lasing wavelength. This results in attenuation of dye laser output through interference of stimulated emission. The roles of singlet oxygen and excitation intensity on dye degradation were explored. Singlet oxygen is formed but its reactions with the dye do not appear to be a major cause of dye laser output deterioration. High light intensity results in dye sensitized, solvent oligomerization to yield materials which interfere with dye stimulated emission. 1, 4-Diazabicyclo2,2,2octane (DABCO)inhibits this oligomerization.

  9. Dye laser traveling wave amplifier

    NASA Technical Reports Server (NTRS)

    Davidson, F.

    1983-01-01

    A flash lamp pumped dye laser suitable for use as an amplifier stage was developed. The desired output laser pulses are of nanosecond duration, tunable in center frequency, and of good optical quality. Its usefulness as a laser oscillator is emphasized, because it constitutes a compact, relatively efficient source of tunable dye laser light.

  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. 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.

  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. 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.

  14. 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.

  15. Dye laser in ophthalmic disease.

    PubMed

    Wang, K S; Wei, Y H; Zhang, M H; Shi, X H; Shi, H Y

    1982-01-01

    From September 1978 to May 1980, dye lasers have been used in the treatment of 56 cases of eye disease (60 eyes), including among others peripheral retinal breaks, macular breaks, prebreak stage degeneration, congenital iris residual membrane, incomplete surgical iridectomy, secondary glaucoma iris bombé, closed-angle glaucoma, vireous hemorrhage, periphlebitis retinae, Coats disease, thrombosis of central and branch retinal vein. Most of the results are satisfactory. Dye laser irradiation has the advantage in iridotomy. Only one pulse can perforate the iris and no serious complication has been encountered. There is a definite therapeutic effect in treatment of vitreous hemorrhage by dye laser. PMID:7109813

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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

  2. 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.

  3. Dye laser traveling wave amplifier

    NASA Technical Reports Server (NTRS)

    Davidson, F.; Hohman, J.

    1984-01-01

    A flashlamp pumped dye laser suitable for use as a single stage amplifier is described. Particular emphasis is placed on the efforts to increase output pulse energy and improve the temporal profile of the injected pulse. By using high power thin film polarizers, output energies reach from 4 to 45 mJ. Various dispersive elements are used to develop an amplified pulse with an extremely clean temporal profile.

  4. Optofluidic circular grating distributed feedback dye laser

    NASA Astrophysics Data System (ADS)

    Chen, Yan; Li, Zhenyu; Henry, M. David; Scherer, Axel

    2009-07-01

    We demonstrate an optically pumped surface emitting optofluidic dye laser using a second-order circular grating distributed feedback resonator. We present a composite bilayer soft lithography technique specifically developed for the fabrication of our dye laser and investigate a hybrid polymer material system [poly(dimethylsiloxane)/perfluoropolyether] to construct high-resolution Bragg gratings. Our lasers emit single frequency light at low lasing thresholds of 6 μJ/mm2. These optofluidic dye lasers can serve as low-cost and compact coherent light sources that are fully integrated within microfluidic analysis chips and provide an efficient approach to construct compact spectroscopy systems.

  5. 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.

  6. Dabco stabilization of coumarin dye lasers

    NASA Astrophysics Data System (ADS)

    Von Trebra, Robert; Koch, Tad H.

    1982-12-01

    1.4-diazabicyclo [2.2.2] octane (DABCO) has been shown to extend the lifetime of several coumarin dyes in nitrogen-laser-pumped and flash-lamp-pumped dye lasers. With 0.010 M DABCO average power output remains at better than 907 of initial power at least three times longer than without DABCO.DABCO is effective in stabilizing dye solutions which are not oxygen degassed and to a lesser extent, in stabilizing oxygen degassed dye solutions. Average power output, pulse duration, and spectral linewidth are not significantly affected. Stabilization is proposed to occur through a combination of dye triplet excited state quenching and quenching of singlet oxygen which results from oxygen quenching of dye triplet states.

  7. 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.

  8. Computer simulation of CPM dye lasers

    SciTech Connect

    Wang Qingyue; Zhao Xingjun )

    1990-01-01

    Quantative analysis of the laser pulses of various intracavity elements in a CPM dye laser is carried out in this study. The pulse formation is simulated with a computer, resulting in an asymmetric numerical solution for the pulse shape. The mechanisms of pulse formation are also discussed based on the results of computer simulation.

  9. Dye laser remote sensing of marine plankton

    NASA Technical Reports Server (NTRS)

    Mumola, P. B.; Jarrett, O., Jr.; Brown, C. A., Jr.

    1973-01-01

    Dye laser, emitting four wavelengths sequentially in time, has been incorporated into helicopter-borne lidar flight package, for performing studies of laser-induced fluorescence of chlorophyll A in algae. Data obtained by multicolor lidar technique can provide water-resource management with rapid-access wide-area coverage of the impact of various environmental factors for any body of water.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. Plasmonic enhancement of Rhodamine dye random lasers

    NASA Astrophysics Data System (ADS)

    Ismail, Wan Zakiah Wan; Vo, Thanh Phong; Goldys, Ewa M.; Dawes, Judith M.

    2015-08-01

    We demonstrate improved characteristics in Rhodamine dye random lasers with the addition of gold nanoparticles. As a result of the strong plasmonic enhancement induced by gold nanoparticles, Rhodamine 640/gold random lasers have less than half the lasing threshold compared with Rhodamine 640/alumina random lasers in the weakly scattering regime for 10-3 M dye concentration. The optimum concentration of gold nanoparticles occurs at ~8  ×  1010 cm-3, close to the transition between the weakly scattering and diffusive regimes. Rhodamine 640 has a better performance compared with Rhodamine 6G which is attributed to the greater spectral overlap of the Rhodamine 6G fluorescence spectrum with the plasmon resonance of gold, leading to an increased energy transfer and fluorescence quenching for Rhodamine 6G by gold. We also observe the contrasting trends of lasing threshold between random dye lasers incorporating dielectric and metal nanoparticles in the diffusive scattering regime. The effects of gold nanoparticles in random dye lasers are discussed in the context of the tradeoff between local field enhancement and fluorescence quenching.

  15. 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.

  16. Comparative laser performances of pyrromethene 567 and rhodamine 6G dyes in copper vapour laser pumped dye lasers

    NASA Astrophysics Data System (ADS)

    Ray, A. K.; Kundu, S.; Sasikumar, S.; Rao, C. S.; Mula, S.; Sinha, S.; Dasgupta, K.

    2007-05-01

    Narrowband laser performances and photochemical stability of alcoholic solutions of pyrromethene 567 and rhodamine 6G dyes, under high-repetition rate copper vapour laser (at 510 nm), as well as, high-peak intensity Nd:YAG laser (at 532 nm) excitation have been investigated. We have observed that pyrromethene 567 dye solutions offer higher efficiency, wider tuning range, but lower photochemical stability and higher lasing threshold than that of rhodamine 6G dye solutions. An addition of about 100 mM DABCO, as a singlet oxygen quencher, in pyrromethene 567 dye solutions improved its photochemical stability close to that of rhodamine 6G. The observation of higher slope efficiency, in spite of higher threshold pump energy for pyrromethene 567 dye than that of rhodamine 6G dye solutions, was explained by a predictive model on gain characteristics of both dye solutions as a function of pump energy.

  17. 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.

  18. Bichromatic emission in a ring dye laser

    NASA Technical Reports Server (NTRS)

    Lawandy, N. M.; Sohrab Afzal, R.; Rabinovich, W. S.

    1987-01-01

    An experimental study of a high-Q Rhodamine 6G ring dye laser has been performed, and bichromatic emission (BE) with wavelength spacings as large as 110 A when the laser operated bidirectionally has been measured. The BE vanished at all excitations when the laser was forced into unidirectional operation using a Faraday isolator. However, when a weak reflected beam was allowed to make a single pass in the direction opposite to that allowed by the Faraday device, BE is recovered at the higher pump powers.

  19. 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.

  20. 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.

  1. 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)

  2. Progress in solid state dye laser development

    SciTech Connect

    Hermes, R.E.

    1990-01-01

    A triaxial flashlamp (15 cm) was used to optically pump laser rods prepared from an acrylate based copolymer (0.95 cm O.D. {times} 10.0 cm L.). The performance of 13 laser dyes incorporated into this polymeric solid host is reported. The best lasing performance was obtained with sulforhodamine-B, with a calculated slope efficiency of 0.52% and a maximum single pulse output energy of 580 mJ. A commercially available fluorescent polymeric material was also evaluated. 12 refs., 2 figs.

  3. Optofluidic microcavities: Dye-lasers and biosensors

    PubMed Central

    Chen, Y.; Lei, L.; Zhang, K.; Shi, J.; Wang, L.; Li, H.; Zhang, X. M.; Wang, Y.; Chan, H. L. W.

    2010-01-01

    Optofluidic microcavities are integrated elements of microfluidics that can be explored for a large variety of applications. In this review, we first introduce the physics basis of optical microcavities and microflow control. Then, we describe four types of optofluidic dye lasers developed so far based on both simple and advanced device fabrication technologies. To illustrate the application potential of such devices, we present two types of laser intracavity measurements for chemical solution and single cell analyses. In addition, the possibility of single molecule detection is discussed. All these recent achievements demonstrated the great importance of the topics in biology and several other disciplines. PMID:24753719

  4. 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)

  5. Dye laser amplifier including a specifically designed diffuser assembly

    DOEpatents

    Davin, James; Johnston, James P.

    1992-01-01

    A large (high flow rate) dye laser amplifier in which a continuous replened 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 relatively high flow rate and a specifically designed diffuser assembly for slowing down the flow of dye while, at the same time, assuring that as the dye stream flows through the diffuser assembly it does so in a stable manner.

  6. Preliminary investigation of the effects of dye concentration on the output of a multiwavelength dye laser

    NASA Technical Reports Server (NTRS)

    Clark, I. O.; Burney, L. G.

    1974-01-01

    The effects of dye concentration on the output wavelength and energy of a multiwavelength dye laser were investigated. The dyes tested were Coumarin 2 in methyl alcohol and Rhodomine 6G, Acridine Red, and 7-diethylamino-4-methyl Coumarin (7DA 4MC) in ethyl alcohol.

  7. A flashlamp pumped zig-zag slab dye laser

    NASA Astrophysics Data System (ADS)

    Dearth, J. J.; Vaughn, V. V.; McGowan, R. B.; Ehrlich, J.; Conrad, R. W.

    In the experiments reported here, the zig-zag principle is extended from solid slab to liquid dye lasers. A zig-zag dye laser is constructed, and the laser beam quality is observed for both straight-through and zig-zag paths. The zig-zag dye cell and its associated flashlamp pumping system are described, and thermally induced effects in the system are discussed.

  8. Dye energy transfer in xerogel matrices and application to solid-state dye lasers

    NASA Astrophysics Data System (ADS)

    Nhung, Tran Hong; Canva, Michael; Chaput, Frédéric; Goudket, Hélène; Roger, Gisèle; Brun, Alain; Manh, Dang Duc; Hung, Nguyen Dai; Boilot, Jean-Pierre

    2004-03-01

    Laser dyes Rhodamine B and Perylene Red were incorporated at different relative concentrations into hybrid matrices synthesized using the sol-gel process. Energy transfer from Rhodamine B-donor to Perylene Red-acceptor molecules was observed. Using the different co-doped samples, solid-state dye laser systems were achieved with tuning band position control and increased efficiency with respect to the materials using solely one type of dye.

  9. 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.

  10. 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.

  11. 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.

  12. Distributed-feedback dye-doped solgel silica lasers.

    PubMed

    Zhu, X L; Lam, S K; Lo, D

    2000-06-20

    Dye-doped solgel silica lasers with distributed feedback were demonstrated. Solgel silica slabs doped with Rhodamine 6G or Coumarin 460 dyes were fabricated. Periodic gain modulation in dye-doped solgel silica slabs were created by the interference pattern of the pumped laser beams diffracted by a holographic grating. Laser pulse trains with subnanosecond spikes were induced. Laser emission wavelengths were centered at 480 and 585 nm for Rhodamine 6G and Coumarin 460, respectively. It was possible for us to tune approximately 20 nm around the emission centers by varying the intersection angle. The laser linewidth was of the order of 60 pm. PMID:18345240

  13. A tunable dual frequency dye laser - dual frequency oscillator design

    NASA Technical Reports Server (NTRS)

    Abury, Y.

    1983-01-01

    The pulsed dye laser offers a tunable oscillator, followed by three amplifiers. It is pumped by a dual frequency Nd:YAG laser. Tuning and spectral width are controlled by a holographic network connected to a high power telescope. The modified two wavelength dye laser allows for absorption lidar techniques for remote sensing of the atmosphere. Line switching is achieved by electrooptical commutation. A feasibility experiment was performed with the original oscillator. A model was then built, and tested with different dyes. After a few modifications were made to improve the conversion efficiency, this oscillator was inserted in the laser to check whether the amplifier stages were correctly adjusted.

  14. Threshold pump power of a solar-pumped dye laser

    NASA Technical Reports Server (NTRS)

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

    1988-01-01

    Threshold solar power for dye laser pumping has been determined by measuring the gain of a rhodamine 6G dye laser amplifier at various solar-simulated irradiances on an amplifier cell. The measured threshold was 20,000 solar constants (2.7 kW/sq cm) for the dye volume of 2 x 5 x 40 cu mm and the optimum dye concentration of 0.001 M. The threshold is about one-third of that achievable with a high-intensity solar concentrator.

  15. Single-mode and tunable microfluidic dye lasers

    NASA Astrophysics Data System (ADS)

    Kristensen, A.; Balslev, S.; Gersborg-Hansen, M.; Bilenberg, B.; Rasmussen, T.; Nilsson, D.

    2006-08-01

    We present a technology for miniaturized, chip-based liquid dye lasers, which may be integrated with microfluidic networks and planar waveguides without addition of further process steps. The microfluidic dye lasers consist of a microfluidic channel with an embedded optical resonator. The lasers are operated with Rhodamine 6G laser dye dissolved in a suitable solvent, such as ethanol or ethylene glycol, and optically pumped at 532 nm with a pulsed, frequency doubled Nd:YAG laser. Both vertically and laterally emitting devices are realized. A vertically emitting Fabry-Perot microcavity laser is integrated with a microfluidic mixer, to demonstrate realtime wavelength tunability. Two major challenges of this technology are addressed: lasing threshold and fluidic handling. Low threshold, in-plane emission and integration with polymer waveguides and microfluidic networks is demonstrated with distributed feed-back lasers. The challenge of fluidic handling is addressed by hybridization with mini-dispensers, and by applying capillary filling of the laser devices.

  16. 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.

  17. 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.

  18. Optofluidic dye laser in a foil.

    PubMed

    Vannahme, Christoph; Christiansen, Mads Brøkner; Mappes, Timo; Kristensen, Anders

    2010-04-26

    First order distributed feedback optofluidic dye lasers embedded in a 350 microm thick TOPAS((R)) foil are demonstrated. They are designed in order to give high output pulse energies. Microfluidic channels and first order distributed feedback gratings are fabricated in parallel by thermal nanoimprint into a 100 microm foil. The channels are closed by thermal bonding with a 250 microm thick foil and filled with 5.10(-3) mol/l Pyrromethene 597 in benzyl alcohol. The fluid forms a liquid core single mode slab waveguide of 1.6 microm height on a nanostructured grating area of 0.5 x 0.5 mm(2). This results in a large gain volume. Two grating periods of 185 nm and 190 nm yield single mode laser light emission at 566 nm and 581 nm respectively. High emitted pulse energies of more than 1 microJ are reported. Stable operation for more than 25 min at 10 Hz pulse repetition rate is achieved. PMID:20588775

  19. Dye laser studies using zig-zag optical cavity

    SciTech Connect

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

    1994-06-01

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

  20. Laser head for simultaneous optical pumping of several dye lasers. [with single flash lamp

    NASA Technical Reports Server (NTRS)

    Mumola, P. B.; Mcalexander, B. T. (Inventor)

    1975-01-01

    The invention is a laser head for simultaneous pumping several dye lasers with a single flash lamp. The laser head includes primarily a multi-elliptical cylinder cavity with a single flash lamp placed along the common focal axis of the cavity and with capillary tube dye cells placed along each of the other focal axes of the cavity. The inside surface of the cavity is polished. Hence, the single flash lamp supplies the energy to the several dye cells.

  1. A hybrid copper/gold laser pumped dye amplifier

    NASA Astrophysics Data System (ADS)

    Ainsworth, M. D.; Piper, J. A.

    1989-01-01

    The design and operating characteristics of a high average power copper vapour laser pumped dye amplifier which is injected with the 627.8 nm output of a gold vapour laser are reported. In these experiments both the CVL pump and GVL injection signals are obtained from a modified CVL plasma tube. Amplifier gain and efficiency as functions of both the pump and injection power, for a number of dyes and dye mixtures, were investigated. Amplifier efficiencies of 25% are reported for CVL pump powers of 4 W and GVL injection powers of only 50 mW.

  2. 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.

  3. 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.

  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. A model of twenty one lines DFB dye laser

    NASA Astrophysics Data System (ADS)

    Khan, N.; Abas, N.

    2009-02-01

    Multiple tunable laser lines were obtained by pumping solution of Rh6G in ethanol (1mM) by five pairs of the second harmonic of a passively Q. switched and mode locked Nd:YAG laser. The time delays among the excitation pulses were varied within coherence length of 1cm. Twenty one equally spaced lines were obtained by pumping dye solution with ten pairs of excitation beams derived from the same source. It was possible to tune the wavelengths by a microcontroller based mirror mounted stage. Number of lasing lines varied from minimum five to maximum twenty one. The wavelength of output lines varied from 540 to 590nm. The pulse lengths were measured, using Hadland Streak Camera, to vary from minimum 10 to maximum 30ps. The experimental results have lead to maturity of a 21-lines model of a distributed feedback dye laser. The dye cell was excited by the 2nd harmonic of a laboratory built passively Q. switched and mode-locked Nd:YAG laser to induce simultaneous temperature phase grating in the dye solution. This work on distributed feedback dye laser is in agreement with most of the published results on semiconductor DFB lasers. Simultaneous operation of 21-lines of slightly varying wavelengths opens a new era of research in biosensors, multiphoton ignition and measurements. This multi-wavelength operation of DFDL is based on mutual couplings of five overwritten dynamic gratings.

  6. 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)

  7. 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.

  8. Dye laser spectrometer for ultrahigh spectral resolution: design and performance.

    PubMed

    Helmcke, J; Lee, S A; Hall, J L

    1982-05-01

    A dye laser spectrometer for ultrahigh spectral resolution is described. The laser frequency is stabilized to the side of a transmission fringe of an optical cavity by means of the usual differencing servo technique. With an intralaser-cavity AD(*)P phase modulator, driven by improved fast servo electronics, the linewidth of the jet stream dye laser was reduced to 1.8 kHz rms. With fast amplitude stabilization a 1.0-kHz line-width was observed. Good long-term stability and digital frequency scanning (with a step resolution of 1 kHz and a continuous tuning range of 900 MHz) are accomplished by transferring the long-term stability of an I(2)-stabilized He-Ne laser to the dye laser via a second optical cavity and an offset locked He-Ne laser. A drift rate of <1 kHz/min was obtained while using this dye laser spectrometer to investigate two-photon optical Ramsey fringes. A fringe width of the Ramsey features of 17 kHz has been observed, confirming for the first time the high resolution capability of two-photon optical Ramsey resonances. PMID:20389917

  9. 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.

  10. 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.

  11. 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.

  12. Solid state dye lasers: rhodamines in silica-zirconia materials.

    PubMed

    Schultheiss, Silke; Yariv, Eli; Reisfeld, Renata; Breuer, Hans Dieter

    2002-05-01

    Silica-zirconia materials as well as silica-zirconia ormosils prepared by the sol-gel technique were doped with the laser dyes Rhodamine B and Rhodamine 6G and used as solid state dye lasers. The photostability and efficiency of the solid state laser samples were measured in a transverse pumping configuration by either a nitrogen laser or the second harmonic of a Nd-YAG laser. Under the excitation of a nitrogen laser the photostability of Rhodamine B in silica-zirconia materials was low and decreased with a growing amount of zirconia. The photophysical properties of the incorporated dyes were studied by time-resolved fluorescence spectroscopy. The fluorescence lifetimes of both dyes increased when the matrix was modified by organic compounds Furthermore, the threshold energy of Rhodamine 6G in two ormosils containing 3 and 50% methylsilica was measured. The results revealed that the threshold energy was lower for the matrix with a higher amount of ormosil while the slope efficiency was higher in the matrix containing 30% ormosil. PMID:12653469

  13. Diode-Pumped Dye Laser Using a Tapered Optical Fiber

    NASA Astrophysics Data System (ADS)

    Patterson, Brian; Stofel, James; Myers, Elliot; Knize, Randy

    2015-05-01

    We describe the construction of a simple dye laser based on a single-mode optical fiber. Light from a 120-mW laser diode (λ = 520 nm) is launched into the fiber. The fiber is tapered to a diameter of approximately 1 μm and placed in Rhodamine 6G laser dye. The pump light interacts with the gain medium through the evanescent field outside the fiber causing stimulated emission, which couples back into the fiber. Mirrors on each end of the fiber provide the necessary feedback for lasing, and a grating is used to narrow the spectral output. We characterize the lasing threshold and output spectrum of the laser. This has been a good project for undergraduate students to learn about lasers and optics.

  14. Pulsed mononode dye laser developed for a geophysical application

    NASA Technical Reports Server (NTRS)

    Jegou, J. P.; Pain, T.; Megie, G.

    1986-01-01

    Following the extension of the lidar technique in the study of the atmosphere, the necessity of having a high power pulsed laser beam with a narrowed bandwidth and the possibility of selecting a particular wavelength within a certain spectral region arises. With the collaboration of others, a laser cavity using the multiwave Fizeau wedge (MWFW) was developed. Using the classical method of beam amplification with the aid of different stages, a new pulsed dye laser device was designed. The originality resides in the use of reflecting properties of the MFWF. Locally a plan wave coming with a particular angular incidence is reflected with a greater than unity coefficient; this is the consequence of the wedge angle which doubles the participation of every ray in the interferometric process. This dye laser operation and advantages are discussed. The feasibility of different geophysical applications envisageable with this laser is discussed.

  15. 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.

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

    NASA Technical Reports Server (NTRS)

    Vanderhoff, John W.; Chen, Jing-Hong

    1993-01-01

    The objective was to determine the feasibility of the preparation of monodisperse spherical poly(methyl methacrylate) and polystyrene particles that contain laser-excitable dyes in the size range 0.1 microns to 1 cm. Poly(methyl methacrylate) and polystyrene were chosen because of their excellent optical properties. The sphericity was required for uniformity of spectral output of re-irradiated light from the dye-containing particles. The monodispersity was required to give each particle the same optical properties when exposed to laser light.

  17. Chemical stabilization of laser dyes. Final report, 1 December 1984-28 February 1987

    SciTech Connect

    Koch, T.H.

    1987-05-07

    Coumarin laser dyes upon excitation degrade to produce products that absorb at the lasing wavelength. This results in attenuation of dye laser output through interference of stimulated emission. The roles of singlet oxygen and excitation intensity on dye degradation were explored. Singlet oxygen is formed but its reactions with the dye do not appear to be a major cause of dye laser output deterioration. High light intensity results in dye-sensitized, solvent oligomerization to yield materials that interfere with dye-stimulated emission. 1, 4-Diazabicyclo2,2,2octane (DABCO)inhibits this oligomerization.

  18. Laser dyes excited by high PRR Nd:YAG laser second-harmonic radiation

    NASA Astrophysics Data System (ADS)

    Soldatov, A. N.; Donin, V. I.; Jakovin, D. V.; Reimer, I. V.

    2008-01-01

    The lasing characteristics of red-emitting dyes in ethanol excited by Nd:YAG laser second-harmonic radiation are examined. The Nd:YAG laser was pumped by a diode matrix. The pump pulse repetition rates (PRRs) were 2.5 - 10 kHz and the pulse duration was 60 - 300 ns. The following dyes were evaluated: oxazine 17, DCM, DCM sp, and pyridine 1. The conversion efficiency for oxazine was 25 % without wavelength selection and 15 % with wavelength selection over the tuning range from 630 to 700 nm. The Nd:YAG and dye laser designs used are described elsewhere [1,2].

  19. Pulsed dye laser fragmentation of ureteral calculi: initial clinical experience.

    PubMed

    Dretler, S P; Watson, G; Parrish, J A; Murray, S

    1987-03-01

    The pulsed dye laser, emitting at wavelengths of 504 nm. for 1 microsecond. at a frequency of 5 Hz. transmitted via a 250 mu in diameter silicon-coated quartz fiber, was passed into the ureter through the working channel of a 9.5F rigid ureteroscope. Seventeen patients with ureteral calculi too large to be extracted directly, who were unable to be treated by extracorporeal shock wave lithotripsy or who otherwise would have required transureteral or percutaneous ultrasonic stone removal, underwent attempted stone fragmentation by pulsed dye laser application. Of the 17 calculi 16 were fragmented to spontaneously passable or easily extractable fragments. There was no significant ureteral injury, thermal or otherwise, attributable to laser energy action. At 3-month followup 15 of the 17 ureters had improved and 2 showed evidence of ureterscopic injury. The mechanism of stone fragmentation by laser is small volume "shock wave" formation. PMID:3820363

  20. Flashlamp pumped solid-state dye laser incorporating pyrromethene 597

    NASA Astrophysics Data System (ADS)

    Finlayson, A. J.; Peters, N.; Kolinsky, P. V.; Venner, M. R. W.

    1999-07-01

    Solid-state rods containing the laser dye pyrromethene 597 (Pyr 597) in a modified polymethyl methacrylate polymer host have been fabricated and shown to give significant lasing action under flashlamp excitation. The rods all displayed a favorable positive-lensing characteristic and also exhibited low bulk transmission losses. The rod with the lowest transmission loss, measured to be 0.31% cm-1 at 633 nm, gave a laser output of 880 mJ with a 0.35% energy efficiency.

  1. Flashlamp pumped polymer dye laser containing Rhodamine 6G

    NASA Astrophysics Data System (ADS)

    Finlayson, A. J.; Peters, N.; Kolinsky, P. V.; Venner, M. R. W.

    1998-04-01

    Polymeric rods incorporating the laser dye Rhodamine 6G in a copolymer of hydroxypropyl acrylate and methylmethacrylate have been shown to lase under flashlamp excitation. The rods exhibit high bulk transmission levels, coupled with positive lensing characteristics, that have enabled output energies up to 354 mJ/pulse with a 0.14% energy efficiency to be demonstrated in a preliminary study.

  2. 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…

  3. Dye laser pumped, continuous-wave KTP optical parametric oscillators

    NASA Astrophysics Data System (ADS)

    Klein, M. E.; Scheidt, M.; Boller, K.-J.; Wallenstein, R.

    1998-06-01

    We report on dye-laser-pumped, continuous-wave (CW) KTiOPO4 (KTP) optical parametric oscillators (OPOs) with pump and idler resonant cavities. With a linear two-mirror cavity the pump power at threshold was 70 mW. The single-frequency signal and idler output wavelengths were tuned in the range of 1025 to 1040 nm and 1250 to 1380 nm by tuning the dye laser in the range of 565 to 588 nm. With a dual three-mirror cavity the threshold was 135 mW. Pumped by 500 mW of 578 nm radiation the 1040 nm single-frequency signal wave output power was 84 mW. Power and frequency stable operation with a spectral bandwidth of less than 9 MHz was obtained by piezo-electrically locking the length of the pump resonant cavity to the dye laser wavelength. Similar performance was achieved by placing the idler resonant OPO inside the resonator of the dye laser. With this system power stable and single-frequency operation was achieved with a spectral bandwidth of less than 11 MHz for the idler wave.

  4. Dye-sensitized solar cells using laser processing techniques

    NASA Astrophysics Data System (ADS)

    Kim, Heungsoo; Pique, Alberto; Kushto, Gary P.; Auyeung, Raymond C. Y.; Lee, S. H.; Arnold, Craig B.; Kafafi, Zakia H.

    2004-07-01

    Laser processing techniques, such as laser direct-write (LDW) and laser sintering, have been used to deposit mesoporous nanocrystalline TiO2 (nc-TiO2) films for use in dye-sensitized solar cells. LDW enables the fabrication of conformal structures containing metals, ceramics, polymers and composites on rigid and flexible substrates without the use of masks or additional patterning techniques. The transferred material maintains a porous, high surface area structure that is ideally suited for dye-sensitized solar cells. In this experiment, a pulsed UV laser (355nm) is used to forward transfer a paste of commercial TiO2 nanopowder (P25) onto transparent conducting electrodes on flexible polyethyleneterephthalate (PET) and rigid glass substrates. For the cells based on flexible PET substrates, the transferred TiO2 layers were sintered using an in-situ laser to improve electron paths without damaging PET substrates. In this paper, we demonstrate the use of laser processing techniques to produce nc-TiO2 films (~10 μm thickness) on glass for use in dye-sensitized solar cells (Voc = 690 mV, Jsc = 8.7 mA/cm2, ff = 0.67, η = 4.0 % at 100 mW/cm2). This work was supported by the Office of Naval Research.

  5. Continuous-wave synchronously pumped femtosecond dye laser at 1. 3. mu. m

    SciTech Connect

    Choa, F.S.; Liu, Y.; Liu, P.

    1989-02-15

    We report a synchronously pumped, cw mode-locked, near-IR dye laser based on the Kodak Q-switch dye No. 5. Benzyl alcohol is used as the solvent to form a flowing dye jet. Synchronously pumped by 2-psec, 950-mW, compressed pulses of a Nd:YAG laser, the dye laser can be tuned from 1210 to 1340 nm with a maximum output of 5 mW and a pulse duration of 600 fsec.

  6. 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.

  7. 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.

  8. 10-Hz kilowatt-class dye laser system

    NASA Astrophysics Data System (ADS)

    Klimek, Daniel E.; Aldag, Henry R.

    1993-06-01

    Textron Defense Systems (Formerly Avco Research Laboratory) has developed a kilowatt class dye laser. The device is a transverse flow, flashlamp pumped laser that operates at greater than 100 Joules per pulse, and at a repetition rate up to 10 Hz. Operating at 10 Hz, an average power of 1.04 kW was obtained at 585 nm using rhodamine 590 in a methanol/water solvent mixture. The output power was increased to 1.4 kW by adding the triplet quencher cyclooctatetraene to the solution. Under these conditions, the measured efficiency (average laser pulse energy/energy stored in flashlamp capacitors) was 1.8%. A limited series of experiments using alternative dyes was also carried out. Comparable energies and average powers were obtained at 610 nm using rhodamine 610, and 660 nm using sulforhodamine 640.

  9. 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.

  10. Development of tunable flashlamp excited dye laser system

    NASA Astrophysics Data System (ADS)

    Bhanthumnavin, V.; Apikitmata, S.; Kochareon, P.

    1991-05-01

    A tunable flashlamp excited dye laser (FEDL) was successfully developed for the first time in Thailand by Thai scientists at KMIT Thonburi (Bangmod). The Rhodamine 6G dissolved in ethyl alcohol was utilized as a laser medium and circulated by a pump through a laser head. The dye cuvette had an inner diameter of 4.0 mm and was 90 mm long. The cavity mirrors M(sub 1), and M(sub 2) were concave mirrors with reflectivities of 100 and 73 percent respectively. A power supply of 0-20 kV and current of 0-50 mA charged a capacitor of 0.3 micro-f at 10-15 kV which was then discharged via a spark gap through the flashlamp. The output laser wavelengths was tunable from lambda = 550-640 nm. It is the first FEDL system, locally developed, which has a tunable wavelength for the laser output. The laser pulse width is about 1.0 microsecond with energy of 20 mJ and peak power pf 20 KW. The repetition rate of the laser is 1/15 Hz.

  11. 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

  12. 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.

  13. Laser dye stability, part 10. Effects of DABCO on flashlamp pumping of coumarin dyes

    NASA Astrophysics Data System (ADS)

    Fletcher, A. N.; Pietrak, M. E.

    1985-07-01

    1,4-Diazabicyclo[2.2.2]octane (DABCO) was tested as a flashlamp-pumped laser lifetime-extender with a variety of coumarin dyes and solvents under both air and argon. In a few cases, DABCO could be considered to have extended the lifetime as much as threefold; however, the selection of the appropriate cover gas and/or solvent could often yield a much greater improvement in the absence of DABCO. In general, DABCO was not found to be very valuable as a lifetime-extender. Furthermore, under some conditions DABCO was found to markedly reduce the laser lifetime and output.

  14. Diffusion driven optofluidic dye lasers encapsulated into polymer chips.

    PubMed

    Wienhold, Tobias; Breithaupt, Felix; Vannahme, Christoph; Christiansen, Mads Brøkner; Dörfler, Willy; Kristensen, Anders; Mappes, Timo

    2012-10-01

    Lab-on-a-chip systems made of polymers are promising for the integration of active optical elements, enabling e.g. on-chip excitation of fluorescent markers or spectroscopy. In this work we present diffusion operation of tunable optofluidic dye lasers in a polymer foil. We demonstrate that these first order distributed feedback lasers can be operated for more than 90 min at a pulse repetition rate of 2 Hz without fluidic pumping. Ultra-high output pulse energies of more than 10 μJ and laser thresholds of 2 μJ are achieved for resonator lengths of 3 mm. By introducing comparatively large on-chip dye solution reservoirs, the required exchange of dye molecules is accomplished solely by diffusion. Polymer chips the size of a microscope cover slip (18 × 18 mm(2)) were fabricated in batches on a wafer using a commercially available polymer (TOPAS(®) Cyclic Olefin Copolymer). Thermal imprinting of micro- and nanoscale structures into 100 μm foils simultaneously defines photonic resonators, liquid-core waveguides, and fluidic reservoirs. Subsequently, the fluidic structures are sealed with another 220 μm foil by thermal bonding. Tunability of laser output wavelengths over a spectral range of 24 nm on a single chip is accomplished by varying the laser grating period in steps of 2 nm. Low-cost manufacturing suitable for mass production, wide laser tunability, ultra-high output pulse energies, and long operation times without external fluidic pumping make these on-chip lasers suitable for a wide range of lab-on-a-chip applications, e.g. on-chip spectroscopy, biosensing, excitation of fluorescent markers, or surface enhanced Raman spectroscopy (SERS). PMID:22820609

  15. Multiline distributed feedback dye laser endorses Wien's displacement law

    NASA Astrophysics Data System (ADS)

    Khan, N.; Abas, N.; Kalair, A.

    2016-04-01

    Peak spectral intensity shifting in a distributed feedback dye laser (DFDL) supporting multiple lines in 550 to 570 nm range is reported. A 3 mM solution of Rh6G in ethanol is pumped with a complex interference pattern of multiple Q-switched and mode-locked frequency-doubled Nd:YAG laser pulses for obtaining numerous discrete laser lines to study the impact of temperature buildup on resonant frequency shifting characteristics. Multiple pulses pumped DFDL are operated at five and nine wavelengths in two separate arrangements and spectra recorded without changing exciting pulses intensities and angles. Higher intensity lines are found to shift during operation from longer to shorter wavelengths due to gradual temperature rise in the dye solution. Laser lines associated with relatively higher intensities shift from lower to higher frequency parts of emission spectrum due to accumulative temperature rise. This temperature-dependent peak intensity drift occurrence becomes faster by reducing the pumping laser interpulse periods. This paper reports gradual heat accumulation stipulated spectral intensity shifts of laser lines in multiline DFDL, which appears to be compliant with Wien's displacement law.

  16. 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.

  17. Spectral characteristics of a ternary-mixture of dyes in a dye laser pumped by copper vapor laser

    NASA Astrophysics Data System (ADS)

    Khare, R.; Shukla, P. K.; Shrivastava, V. K.; Nakhe, S. V.

    2014-02-01

    The spectral characteristics of a ternary-mixture, composed of Rhodamine 640, Rhodamine 6G and DCM in ethanol and excited by copper vapor laser, are reported. The concentration of each dye in the ternary-mixture was optimized to provide peak emission at 633 nm and absorb both wavelengths of copper vapor laser, i.e. 510.6 and 578.2 nm. A fluorescence range of 612-679 nm with a relatively broad peak at 631-634 nm was obtained when concentrations of Rhodamine 640, Rhodamine 6G and DCM in the ternary-mixture were 0.90 mM, 0.30 mM and 0.90 mM respectively. This ternary-mixture of dyes in ethanol, when used as a gain medium in a narrowband, tunable dye laser oscillator, transversely pumped by both wavelengths of a copper vapor laser, provided a spectral tuning range of 620-665 nm with an almost flat peak at 630-634 nm.

  18. 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.

  19. 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.

  20. 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.

  1. Ar-ion-laser-pumped infrared dye laser at 875-1084 nm

    SciTech Connect

    Kato, K.

    1984-12-01

    High-efficiency high-power cw dye-laser operation has been acheived from 875 to 1084 nm by pumping two styryl derivatives with an Ar-ion laser. Peak output powers as high as 900 and 750 mW were obtained around 925 and 980 nm, respectively.

  2. 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.

  3. 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)

  4. Broad band tunable dye laser development

    NASA Astrophysics Data System (ADS)

    Lee, Jong Min; Kim, Jung Bog; Kim, Sung Ho; Go, Do Kyung; Lim, Chang Hwan; Rho, Si Pyo; Song, Kyu Seok; Lee, Byung Cheol; Rhi, Jong Hoon; Han, Jae Min

    1992-12-01

    The technical goal and objectives are the development of a tunable laser which can be tuned from UV to near IR and commercialization for uses in various fields. Two kinds of resonators are developed. The user can select one resonator and change into the other without changing other parts. GIM type has a linewidth of 5 GHz which is able to be used usually, and a SLM type which has a very narrow linewidth of less than 1 GHz. Each system can have one or two amplifiers depending on output power or cost. High stability and safety, cost-down, and modules into about 30 components have been tried. We hope that this laser can help developments in researches of university, industry, and institute.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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

  11. High laser efficiency and photostability of pyrromethene dyes mediated by nonpolar solvent.

    PubMed

    Gupta, Monika; Kamble, Priyadarshini; Rath, M C; Naik, D B; Ray, Alok K

    2015-08-10

    Many pyrromethene (PM) dyes have been shown to outperform established rhodamine dyes in terms of laser efficiency in the green-yellow spectral region, but their rapid photochemical degradation in commonly used ethanol or methanol solvents continues to limit its use in high average power liquid dye lasers. A comparative study on narrowband laser efficiency and photostability of commercially available PM567 and PM597 dyes, using nonpolar n-heptane and 1,4-dioxane and polar ethanol solvents, was carried out by a constructed pulsed dye laser, pumped by the second harmonic (532 nm) radiation of a Q-switched Nd:YAG laser. Interestingly, both nonpolar solvents showed a significantly higher laser photostability (∼100 times) as well as peak efficiency (∼5%) of these PM dyes in comparison to ethanol. The different photostability of the PM dyes was rationalized by determining their triplet-state spectra and capability to generate reactive singlet oxygen (O21) by energy transfer to dissolved oxygen in these solvents using pulse radiolysis. Heptane is identified as a promising solvent for these PM dyes for use in high average power dye lasers, pumped by copper vapor lasers or diode-pumped solid-state green lasers. PMID:26368369

  12. Thermally induced refractive index gradients in a dye-laser cell

    NASA Astrophysics Data System (ADS)

    Burshtein, Z.; Levron, D.; Bialolenker, G.

    1988-11-01

    The program GABI calculates refractive index gradients generated in a dye solution, flowing in a planar cell, and pumped by a repetitively pulsed copper vapor laser beam. The calculation results serve for design evaluation and selection of optimal pump geometry, dye solvent and dye solution flow velocity.

  13. 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.

  14. 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.

  15. 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.

  16. Comparison of the argon tunable dye laser with the flashlamp pulsed dye laser in treatment of facial telangiectasia

    NASA Astrophysics Data System (ADS)

    Broska, Pamela; Martinho, Elena; Goodman, Matthew M.

    1992-06-01

    A prospective, side-by-side comparison study of two different lasers for the treatment of solar- induced telangiectasia was carried out in 14 patients at the Beckman Laser Institute and Medical Clinic. The argon tunable dye laser (Coherent, Palo Alto, Calif.) was used in the method modified from Orenstein and Nelson to completely treat discrete telangiectasias on one cheek. Specifically, the argon tunable dye laser (ATDL) was set at 0.7 - 0.8 watts, 585 nm wavelength, shutter-pulsed at 0.1 second duration with a spot size of 0.1 mm, and individual vessels were 'traced out' with 4X loupe magnification. Each patient's opposite cheek was then treated in the standard fashion with the flashlamp pulsed dye laser (Candela, Natick, Mass.) using a technique similar to Polla's et al. Specifically, the flashlamp pulsed dye laser (FPDL) was set at 585 nm wavelength, pulsed mode of 450 microseconds pulse duration, spot size of 5 mm, overlapping 10 - 20%, with power densities of 5.5 to 6.5 joules/cm2. All patients had symmetrical cheek telangiectasias of several years' duration. Patients were treated on day 0, and examined on weeks 2, 4, and 6. Photos were taken at each visit, and evaluation was done by questionnaire and direct observation, as well as by photographic slides later projected to an impartial panel. Final evaluation by the panel at week 6 showed 11/14 patients with excellent results (75 - 100% clearing) at sites treated with the FPDL, compared with 4/14 with the ATDL. In contrast, 4/14 FPDL sites were graded as fair to minimal improvement, and 9/14 as fair for the ATDL. The patients' self-evaluations graded the final results very similar to that of the panel. Most patients were bothered by the ecchymosis and hyperpigmentation associated with the FPDL, resulting in less than 50% of the patients preferring the FPDL despite its more impressive results. We conclude that the final results favor the FPDL over the ATDL for treatments of facial telangiectasia. However, non

  17. A Moiré Cavity Plasmonic Dye Laser

    NASA Astrophysics Data System (ADS)

    Karademir, Ertugrul; Balci, Sinan; Kocabas, Coskun; Aydinli, Atilla

    2015-03-01

    From its first conception to its first demonstration, plasmonic lasers have been an intriguing topic of research. In this work, Moiré gratings which manifest a cavity state in the SPP dispersion curve. We used a reverse Kretschmann setup to decouple the amplified light component of SPPs. We employed a Moiré cavity with 250 +256 nm periodicity together with a Styryl 7 laser dye dissolved in ethylene glycol in 5 mM concentration and obtained a lasing at 718 nm. Pumping threshold was 1.5 mJ/cm2 with FWHM of 2.8 nm. Furthermore, periodicities of 242 +248 nm and 260 +266 nm resulted in proportional shift of the lasing peak. We did not observe any lasing action on samples with Au and Ti coatings, although solely Au coated samples showed plasmonic modes in the spectrum. Resulting lasing peak is highly TM polarized. Reflection map measurements confirm that lasing mode is supported with the cavity state of the metallic Moiré cavity and simulations support reflection map measurements. Thus, we demonstrated, to our knowledge, the first plasmonic dye laser on a Moiré cavity. TUBITAK 110T790, 110T589, 112T091.

  18. 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.

  19. 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.

  20. Evaluation of laser dye mutagenicity using the Ames/Salmonella microsome test

    SciTech Connect

    Wuebbles, B.J.Y.; Felton, J.S.

    1985-01-01

    Twenty-five laser dyes and four analogs were tested for mutagenicity in the Ames/Salmonella test. Seven dyes and two analogs gave positive mutagenic responses with bacterial strains TA-1538 and TA98. Of two widely used families of laser dyes (coumarins and rhodamines), four coumarin samples, but none of the rhodamine samples, were mutagenic. Using high-performance liquid chromatography (HPLC), it was determined that five mutagenic dye samples had multiple components. The dyes themselves may not be the mutagenic agents in all cases (as with Nile Blue) but may contain impurities that are mutagenic. This study indicates the need for further toxicological testing of these types of compounds. The mutagenic components of these dye mixtures, whether it is the dye or a contaminant, presents a possible hazard to those handling them. Therefore, practices and procedures for the safe handling of specific dyes should be reviewed in light of these findings.

  1. 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)

  2. 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.

  3. New laser dyes based on 3-imidazopyridylcoumarin derivatives

    NASA Astrophysics Data System (ADS)

    Anufrik, S. S.; Tarkovsky, V. V.; Sazonko, G. G.; Asimov, M. M.

    2012-03-01

    A comparative analysis of the spectral-luminescent characteristics and generation parameters of a number of 3-imidazopyridylcoumarin derivatives has been carried out under nano- and microsecond excitation by coherent and incoherent light. New coumarin dyes are offered that feature the ability to lase under different types of pumping in the spectral range 525-580 nm; high lasing efficiency reaching 20% and 1% under laser and lamp pumping, respectively; and high photochemical stability (3-5 times higher than that of rhodamine 6 G) under conditions of powerful nonmonochromatic pumping.

  4. [Peculiarity of pulsed dye laser lithotriptor and its clinical application].

    PubMed

    Matsumoto, T; Miki, M; Mamiya, Y; Hirata, T; Shimizu, H; Tochimoto, M; Ito, T; Aika, T

    1989-09-01

    Ultrasound lithotriptors (USL) and electrohydraulic lithotriptors (EHL) are representative lithotriptors for endoscopic elimination of upper urinary tract stones. However, they have some disadvantages. For example, USL can not be used with flexible scopes and EHL can cause unexpected tissue injury. To overcome these problems, the pulsed dye laser lithotriptor (MDL-1, Candera Co.) was developed. The characteristics of this laser lithotriptor and its direct effects on tissue was investigated. This pulsed dye laser lithotriptor generates a 504 nm wavelength green light beam by using a combination of a xenon flash lamp and the greenish dye composed of coumarin solution. The maximum output energy is 60 mJ/pulse and the pulse duration is 1.5 microsecond. The pulse rate can be varied from 1 to 20 Hz. First, the intensity of the shock wave was measured by using a combination of a piezoelectric element and an oscilloscope, and then, the results were compaired with those obtained by a similar experiment with an EHL. The average intensity of the shock wave was 54.4 mW under the conditions of 40 mJ/pulse of output energy and 10 Hz of pulse duration. On the other hand, the EHL generated an average of 54.7 W under the conditions of 400 mJ/pulse output energy. Then, fragmentation of various kinds of urinary stones in saline solution was performed. The results showed that this lithotriptor could fragment almost all kinds of stones except cystine stones. Then, hen's eggs were used to observe the effect if laser bean influenced on the organism immediately behind the photoradiated object. Only the egg shell was demolished but the egg membrane below the eggshell did not undergo any change. After these experiments, skin, liver, kidney and urinary bladder of nude mice and human prostatic urethral mucosa in case of TUR-P were irradiated by this laser. The results showed that laser energy caused slight penetration and localized hemorrhage from the surface of epithelium to subcutaneous

  5. Picosecond pulses produced by mode locking a Nd:glass laser with Kodak dye number26

    SciTech Connect

    Schiller, N.H.; Foresti, M.; Alfano, R.R.

    1985-05-01

    Kodak dye number26 was used to generate picosecond laser pulses by mode locking a Nd:glass laser. The intensity profiles and characteristics of the pulses were compared with those of pulses emitted using dyes number5 and number9860.

  6. 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

  7. 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.

  8. 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

  9. 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

    A compact and simple simultaneous multi-wavelength dye laser cavity was developed for a differential absorption technique. Dielectric multilayer interference filters were inserted inside the cavities as tuning elements, and two types of a DIAL system were constucted by using the dye laser tuned with dielectric multilayer filters to measure NO2 concentration. The usefulness of this dye laser was clarified for the differential absoroption technique in outdoor experiments. Some basic designs of the laser cavity with these filters to get simultaneously multi-wavelength output are summarized.

  10. Photophysics of Laser Dye-Doped Polymer Membranes for Laser-Induced Fluorescence Photogrammetry

    NASA Technical Reports Server (NTRS)

    Dorrington, Adrian A.; Jones, Thomas W.; Danehy, Paul M.

    2004-01-01

    Laser-induced fluorescence target generation in dye-doped polymer films has recently been introduced as a promising alternative to more traditional photogrammetric targeting techniques for surface profiling of highly transparent or reflective membrane structures. We investigate the photophysics of these dye-doped polymers to help determine their long-term durability and suitability for laser-induced fluorescence photogrammetric targeting. These investigations included experimental analysis of the fluorescence emission pattern, spectral content, temporal lifetime, linearity, and half-life. Results are presented that reveal an emission pattern wider than normal Lambertian diffuse surface scatter, a fluorescence time constant of 6.6 ns, a pump saturation level of approximately 20 micro J/mm(exp 2), and a useful lifetime of more than 300,000 measurements. Furthermore, two demonstrations of photogrammetric measurements by laser-induced fluorescence targeting are presented, showing agreement between photogrammetric and physically measured dimensions within the measurement scatter of 100 micron.

  11. Comparative histological studies of the tunable dye (at 577 nm) laser and argon laser: the specific vascular effects of the dye laser

    SciTech Connect

    Greenwald, J.; Rosen, S.; Anderson, R.R.; Harrist, T.; MacFarland, F.; Noe, J.; Parrish, J.A.

    1981-09-01

    This study compares the histological changes occurring after argon laser and dye laser (operating at 577 nm) treatment of normal human skin. The initial effect of the argon laser is a diffuse nonspecific epidermal and upper dermal necrosis with subsequent cell death and a neutrophilic response at 48 hr. These changes occur at 15 joules/cm2 and their extent closely correlates with the energy applied. In sharp contrast, the immediate effect of the dye laser is erythrocyte aggregation, vessel rupture, and hemorrhage. At 48 hr, there is a pattern of acute vasculitis in the upper dermis and a prominent perivascular neutrophilic response in the mid-dermis. Focal epidermal necrosis does occur but is relatively minimal, while skin appendages and collagen are preserved. The energy to produce these alterations is relatively small, approximately 3 J/cm2. Thus, the dye laser at 577 nm can selectively damage the cutaneous vascular plexus and may provide a basis for treatment of cutaneous vascular lesions.

  12. 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.

  13. 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.

  14. Ultralow detection limits for an organic dye determined by fluorescence spectroscopy with laser diode excitation

    SciTech Connect

    Johnson, P.A.; Barber, T.E.; Smith, B.W.; Winefordner, J.D. )

    1989-04-15

    Fluorescence of IR-140, a laser dye in methanol solution, is excited by a semiconductor laser diode. Analytical figures of merit are compared for three different instrumental configurations, with the dye measured in a cuvette, a liquid jet, and a compact instrument. The best limit of detection, 46,000 molecules, was achieved with a liquid jet. Linear dynamic range was 6 orders of magnitude. The laser diode operates in the near-infrared region, resulting in low background fluorescence.

  15. Single-mode operation of a long-pulse flashlamp pumped dye laser

    SciTech Connect

    Mandl, A.; Klimek, D.E.; Chou, H.P.; Litzenberger, L.; Wang, Y.

    1995-02-01

    The authors describe the achievement of single-mode operation of a flashlamp pumped long-pulse, {approximately} 700 ns dye laser, with output energy of about 350 mJ using a linear optical cavity with a ``twisted mode`` configuration. Measurements indicate that the laser frequency chirps by about 40 MHz over the entire pulse. Homodyne measurements indicate that the instantaneous bandwidth is close to the transform limit. This represents a significant advance in dye laser performance.

  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. PMID:25402105

  17. Improving dye laser efficiency with uv absorbers and wavelength shifters. Final report

    SciTech Connect

    Matheson, K L; Thorne, J M

    1981-01-01

    The nonuniform heating in flashlamp pumped dye lasers forms refractive index gradients in the dye solution. These gradients distort the wavefront of the laser beam resulting in limited output power, limited pulse repetition rate, and limited attainable linewidth. The theorectical bases for using uv absorbers and wavelength shifters to eliminate light of detrimental wavelengths and thereby improve dye laser efficiency are described, and the results of experiments for evaluating 12 uv absorbers and 12 wavelength filters for use as possible pump light filters are presented. These experiments showed that the appropriate uv absorber or wavelength shifter to be used with a given laser dye is based on the absorption spectrum of the dye. If a uv absorber is needed, then the compound should be chosen so that its long wavelength absorption peak is just to the short wavelength side of the absorption peaks of the laser dye. If a wavelength shifter is needed, then the compound should be chosen so that there is maximum overlap between the fluorescence spectrum of the shifter and the absorption spectrum of the dye. Tabulated data are presented which can be used to selected protectors and shifters for specific dyes. (LCL)

  18. High-repetition-rate tunable dye lasers pumped by copper vapor laser

    SciTech Connect

    Zherikin, A.N.; Letokhov, V.S.; Mishin, V.I.; Belyaev, V.P.; Evtyunin, A.N.; Lesnoi, M.A.

    1981-06-01

    A study was made of stimulated emission and amplification of light in lasers with active media consisting of alcohol solutions of rhodamines 110, 6G, and B, and of oxazine 17. The pulse repetition frequency was 10 kHz and pumping was provided by a mass-produced copper vapor laser of the ILGI-101 type. The dye lasers emitted in the range 530--720 nm. The efficiency of the oxazine 17 laser was 20% and the efficiency of the rhodamine 6G amplifier was 30% when the width of the laser emission spectrum was 0.8 cm/sup -1/. A Fabry--Perot interferometer was used to reduce the width of the spectrum to 0.04 cm/sup -1/, but this reduced the efficiency to 7%. The maximum output power was 0.6 W. The radiation was transformed to the second harmonic in the 265--360 nm range with an efficiency of 5%.

  19. BRIEF COMMUNICATIONS: High-repetition-rate tunable dye lasers pumped by copper vapor laser

    NASA Astrophysics Data System (ADS)

    Zherikin, A. N.; Letokhov, V. S.; Mishin, V. I.; Belyaev, V. P.; Evtyunin, A. N.; Lesnoĭ, M. A.

    1981-06-01

    A study was made of stimulated emission and amplification of light in lasers with active media consisting of alcohol solutions of rhodamines 110, 6G, and B, and of oxazine 17. The pulse repetition frequency was 10 kHz and pumping was provided by a mass-produced copper vapor laser of the ILGI-101 type. The dye lasers emitted in the range 530-720 nm. The efficiency of the oxazine 17 laser was 20% and the efficiency of the rhodamine 6G amplifier was 30% when the width of the laser emission spectrum was 0.8 cm-1. A Fabry-Perot interferometer was used to reduce the width of the spectrum to 0.04 cm-1, but this reduced the efficiency to 7%. The maximum output power was 0.6 W. The radiation was transformed to the second harmonic in the 265-360 nm range with an efficiency of 5%.

  20. 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.).

  1. Spectroscopic properties and amplified spontaneous emission of fluorescein laser dye in ionic liquids as green media

    NASA Astrophysics Data System (ADS)

    AL-Aqmar, Dalal M.; Abdelkader, H. I.; Abou Kana, Maram T. H.

    2015-09-01

    The use of ionic liquids (ILs) as milieu materials for laser dyes is a promising field and quite competitive with volatile organic solvents and solid state-dye laser systems. This paper investigates some photo-physical parameters of fluorescein dye incorporated into ionic liquids; 1-Butyl-3-methylimidazolium chloride (BMIM Cl), 1-Butyl-3-methylimidazolium tetrachloroaluminate (BMIM AlCl4) and 1-Butyl-3-methylimidazolium tetrafluoroborate (BMIM BF4) as promising host matrix in addition to ethanol as reference. These parameters are: absorption and emission cross-sections, fluorescence lifetime and quantum yield, in addition to the transition dipole moment, the attenuation length and oscillator strength were also investigated. Lasing characteristics such as amplified spontaneous emission (ASE), the gain, and the photostability of fluorescein laser dye dissolved in different host materials were assessed. The composition and properties of the matrix of ILs were found that it has great interest in optimizing the laser performance and photostability of the investigated laser dye. Under transverse pumping of fluorescein dye by blue laser diode (450 nm) of (400 mW), the initial ASE for dye dissolved in BMIM AlCl4 and ethanol were decreased to 39% and 36% respectively as time progressed 132 min. Relatively high efficiency and high fluorescence quantum yield (11.8% and 0.82% respectively) were obtained with good photostability in case of fluorescein in BMIM BF4 that was decreased to ∼56% of the initial ASE after continuously pumping with 400 mW for 132 min.

  2. 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…

  3. Study of the mechanisms of laser-induced release of liposome-encapsulated dye

    SciTech Connect

    Khoobehi, B.; Char, C.A.; Peyman, G.A.; Schuele, K.M. )

    1990-01-01

    To differentiate the contributing factors (blood or encapsulated dye) leading to the release of encapsulated dyes from liposomes after laser exposure, we initiated an in vitro experimental study. The release of encapsulated calcein was quantified under various experimental conditions in whole blood and in buffered solution containing high-density lipoprotein. Generally, the amount of dye release improved with an increase in laser power, with a maximum release of approximately 80% of encapsulated dye. Because the laser exposure was not continuous, only 80% of each sample was actually exposed. Therefore, 80% release may be thought of as total release. In a lipoprotein/buffer mixture, the 488 nm wavelength caused greater dye release than the 577 nm wavelength, because the maximum absorption of calcein is near 488 nm. The laser wavelength at 577 nm, however, caused greater release in the blood mixture, reflecting the peak absorption of hemoglobin at near 577 nm. At a 3 x higher liposome concentration, the differences in the effects of wavelengths on the release of dye from liposomes were insignificant. Although the 577 nm wavelength is an optimum wavelength for dye and drug delivery in the presence of blood, the 488 nm wavelength might also be suitable for the release of dye from the liposomes.

  4. 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.

  5. 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.

  6. Solid hosts for dye laser rods: Part 2, Some experimental results

    SciTech Connect

    Erickson, G.F.

    1987-01-01

    Attempts and problems encountered in producing high quality polymer dye laser rods are discussed. Purification methods used on the monomer materials, curing agent problems, and gamma radiation curing are considered. 7 figs.

  7. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2014-08-01

    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 (1S0-3P0) in an Ytterbium optical lattice clock and perform high-resolution spectroscopy of iodine molecules trapped in the sub-nanometer channels of zeolite crystal (AlPO4-11). 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 × 10-15 (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.

  9. Frequency tuning of a distributed feedback dye laser with two transmission gratings.

    PubMed

    Cui, Y; Ding, T N; Hatten, D L; Hill, W T; Goldhar, J

    1993-11-20

    Distributed feedback dye lasers, which use a holographic grating, present a very simple and reliable way to generate ultrashort pulses. We have developed a new technique for wavelength tuning of this type of laser by projecting the image of a second grating into the dye cell. Single-line operating and tuning was demonstrated with transform-limited output pulses on a picosecond time scale. PMID:20856504

  10. 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.

  11. 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)

  12. 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.

  13. 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.

  14. 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.

  15. Enhancement of the efficiency of dye lasers using electron energy transfer processes

    NASA Astrophysics Data System (ADS)

    Levin, M. B.; Uzhinov, B. M.

    1990-04-01

    Various types of electron energy transfer processes are considered, which are associated with the introduction of energy donors (Dn) and triplet quenchers (TQ) into the acceptor dye solutions with the use of luminescent light filters (LLF) in the pumping system. Mixed solutions are proposed which make it possible to increase the efficiency of the coumarine 314 dye laser by a factor of 1.8. In lasers using unsubstituted and B rhodamines, the simultaneous action of Dn, TQ, and LLF leads, in the optimal cases, to a three-to-ten-fold increase in the efficiency, making the efficiency of these dyes close to that of rhodamine 6G.

  16. Blue-to-orange color-tunable laser emission from tailored boron-dipyrromethene dyes.

    PubMed

    Esnal, Ixone; Valois-Escamilla, Ismael; Gómez-Durán, César F A; Urías-Benavides, Arlette; Betancourt-Mendiola, María L; López-Arbeloa, Iñigo; Bañuelos, Jorge; García-Moreno, Inmaculada; Costela, Angel; Peña-Cabrera, Eduardo

    2013-12-16

    A series of meso-substituted boron-bipyrromethene (BODIPY) dyes are synthesized and their laser and photophysical properties systematically studied. Laser emission covering a wide visible spectral region (from blue to orange) is obtained by just changing the electron donor character of the heteroatom at position 8. The additional presence of methyl groups at positions 3 and 5 results in dyes with a photostability similar to that of the unsubstituted dye but with much improved efficiency. Correlation of the lasing properties of the different dyes to their photophysical properties provides inklings to define synthetic strategies of new BODIPY dyes with enhanced efficiency and modulated wavelength emission over the visible spectral region. PMID:24255000

  17. Molecular origins of optoelectronic properties in coumarin dyes: toward designer solar cell and laser applications.

    PubMed

    Liu, Xiaogang; Cole, Jacqueline M; Waddell, Paul G; Lin, Tze-Chia; Radia, Jignesh; Zeidler, Anita

    2012-01-12

    Coumarin derivatives are used in a wide range of applications, such as dye-sensitized solar cells (DSCs) and dye lasers, and have therefore attracted considerable research interest. In order to understand the molecular origins of their optoelectronic properties, molecular structures for 29 coumarin laser dyes are statistically analyzed. To this end, data for 25 compounds were taken from the Cambridge Structural Database and compared with data for four new crystal structures of coumarin laser dyes [Coumarin 487 (C(19)H(23)NO(2)), Coumarin 498 (C(16)H(17)NO(4)S), Coumarin 510 (C(20)H(18)N(2)O(2)), and Coumarin 525 (C(22)H(18)N(2)O(3))], which are reported herein. The competing contributions of different resonance states to the bond lengths of the 4- and 7-substituted coumarin laser dyes are computed based on the harmonic oscillator stabilization energy model. Consequently, a positive correlation between the contribution of the para-quinoidal resonance state and the UV-vis peak absorption wavelength of these coumarins is revealed. Furthermore, the perturbations of optoelectronic properties, owing to chemical substituents in these coumarin laser dyes, are analyzed: it is found that their UV-vis peak absorption and lasing wavelengths experience a red shift, as the electron-donating strength of the 7-position substituent increases and/or the electron-withdrawing strength of the 3- or 4-position substituent rises; this conclusion is corroborated by quantum-chemical calculations. It is also revealed that the closer the relevant substituents align with the direction of the intramolecular charge transfer (ICT), the larger the spectral shifts and the higher the molar extinction coefficients of coumarin laser dyes. These findings are important for understanding the ICT mechanism in coumarins. Meanwhile, all structure-property correlations revealed herein will enable knowledge-based molecular design of coumarins for dye lasers and DSC applications. PMID:22117623

  18. Tunable ultraviolet co-doped dye laser of Pyrromethene 597 and Rhodamine 610

    NASA Astrophysics Data System (ADS)

    Lu, Zhenzhong; Sun, Yanling; Ma, Lin; Liu, Jifang

    2015-12-01

    The laser performance of Pyrromethene 597 (PM597) and Rhodamine 610 mixture is studied. A wide tuning range from 580 to 655 nm is achieved. The laser linewidth obtained is less than 0.1 nm. The highest conversion efficiency of 42.5% is obtained at 600 nm. Using a beta-BaB2O4 (BBO) crystal to frequency double the dye laser into ultraviolet (UV), a tuning range from 296 to 324 nm is obtained. The peak conversion efficiency from the dye laser to the UV laser is 9.7% and the highest UV laser output energy is 9.51 mJ at 301.25 nm. To the best of our knowledge, the tuning range and the conversion efficiency are the best under the same condition so far. All our results indicate that high laser performance can be achieved using a laser dyes’ mixture.

  19. Two-threshold silver nanowire-based random laser with different dye concentrations

    NASA Astrophysics Data System (ADS)

    Wang, Zhaona; Shi, Xiaoyu; Wei, Sujun; Sun, Yanyan; Wang, Yanrong; Zhou, Jing; Shi, Jinwei; Liu, Dahe

    2014-09-01

    The feedback mechanisms of silver nanowire-based random lasers with different concentrations of laser dye rhodamine 6 G pumped by a nanosecond pulsed laser were demonstrated. It was shown that dye concentration greatly impacts on the optical amplification mechanism. At lower or higher dye concentrations, random lasers have a single threshold. At a proper concentration, the system shows transition from incoherent emission to coherent lasing and has two thresholds corresponding to incoherent feedback and coherent feedback, respectively. The corresponding physical mechanism was displayed. Also, the processes of fluorescence, incoherent feedback and coherent feedback were distinguished by the emission spectra in the time domain. The results will supply some guidance to clear the working mechanism of random lasers.

  20. 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)

  1. 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.

  2. The electrically and magnetically controllable random laser from dye-doped liquid crystals

    NASA Astrophysics Data System (ADS)

    Ye, Lihua; Liu, Bo; Zhao, Chong; Wang, Yan; Cui, Yiping; Lu, Yanqing

    2014-08-01

    The electrically and magnetically controllable random laser from dye-doped liquid crystals (LCs) was studied. The rubbing-alignment of the polyimide in the LC cell influenced the threshold voltage and the response time of the electrically controllable random laser. When the applied electric field was increased, the response time of the random laser decreased. The magnetically controllable random laser was studied in the hollow fiber structure, of which the response time was less than 1 s.

  3. 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.

  4. Recent progress in the development of electrically and optically pumped dye vapor lasers

    NASA Astrophysics Data System (ADS)

    Marowsky, G.

    1980-01-01

    This paper reviews new results in the field of organic dye vapor lasers. Gain studies of the scintillator dye POPOP in liquid solution and in the vapor phase show that a dye vapor exhibits optical gain nearly as high as in the solution case under excitation by a N2 laser. Superradiant emission has been observed from both optically excited POPOP vapor and electron-beam excited vapor. The optimum operating conditions of an electron-beam pumped dye vapor-buffer gas system with high purity argon as buffer are reported. Potential energy transfer processes from the rare-gas buffer to the dye vapor are discussed. The metastable ionic species Ar2(+) has been identified as the most likely POPOP excitation source after intense electron pumping of the dense Ar buffer gas at typically 4-5 atm. An estimate of the conversion efficiency from electronic energy deposited in the Ar buffer to stimulated emission of the dye yields 5 percent. These results suggest that an efficient tunable electron beam pumped dye vapor laser is feasible.

  5. 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.

  6. 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)

  7. 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. ...

  8. Thin-film waveguide evanescent dye laser and its gain measurement

    SciTech Connect

    Sasaki, K.; Fukao, T.; Saito, T.; Hamano, O.

    1980-06-01

    Superradiant waveguide evanescent-type dye lasers are realized by polyurethane top layers containing Rhodamine 6G and Rhodamine B respectively on single-mode glass waveguides with N/sub 2/ uv laser pumping. A new determination method of gain factor (negative absorption coefficient) by active guide length dependence of a triangle shape top layer is proposed.

  9. Thin-film waveguide evanescent dye laser and its gain measurement

    NASA Astrophysics Data System (ADS)

    Sasaki, K.; Fukao, T.; Saito, T.; Hamano, O.

    1980-06-01

    Superradiant waveguide evanescent-type dye lasers are realized by polyurethane top layers containing Rhodamine 6G and Rhodamine B respectively on single-mode glass waveguides with N2 UV laser pumping. A new determination method of gain factor (negative absorption coefficient) by active guide length dependence of a triangle shape top layer is proposed.

  10. Pulse-width stabilization of a synchronously pumped mode-locked dye laser

    NASA Astrophysics Data System (ADS)

    Rotman, S. R.; Roxlo, C. B.; Salour, M. M.; Bebelaar, D.

    1980-06-01

    Using an analog feedback loop acting on the mode-locker frequency of a synchronously pumped mode-locked dye laser, a substantial decrease of pulse-width variations at frequencies up to 10 kHz at the cost of an increase in higher-frequency noise was observed. A digital loop acting on the cavity length decreased noise at low frequencies. Using these methods, reproducible and stabilized frequency-tunable subpicosecond pulses were generated, and the effects of noise in the mode-locking frequency of the pumping Ar(+) laser and drift in the cavity length of the dye laser were determined.

  11. 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.

  12. Multipulse operation of a high average power, good beam quality zig-zag dye laser

    SciTech Connect

    Mandl, A.; Klimek, D.E.

    1996-03-01

    A laser pumped zig-zag dye laser operating at 568 nm with a pulse length {approximately} 2 {micro}s has been scaled to high power using a MOPA configuration. Pulse energies in excess of 7 J with beam quality < 2 XDL have been achieved under repetitively pulsed, 10 Hz operation. RMS jitter was measured as 0.12 of a 1 XDL spot. The device has operated with over 70 W output for runs up to 5 s. Substantially longer run times and output powers are possible. This device represents an advance in dye laser capabilities. Improvement in pointing accuracy of better than an order of magnitude have been demonstrated. In addition, an improvement in beam quality by about an order of magnitude has been achieved compared to other dye lasers operating in this power range.

  13. A computational model for transient temperature rise in a dye laser gain medium pumped by a copper vapor laser

    NASA Astrophysics Data System (ADS)

    Rawat, V. S.; Gantayet, L. M.; Sridhar, G.; Singh, S.

    2014-02-01

    Spectrally stable dye lasers play an important role in techniques based on high resolution spectroscopy and atomic spectroscopy. The spectral purity of a dye laser is affected when the pump power to it is increased beyond the threshold. When the pump power is increased beyond the threshold, two mode oscillations occur which decrease the spectral purity of the dye laser. The effect of higher pump pulse energies on transient thermal effects has been studied using a computational fluid dynamics (CFD) model and the disturbances to the laser cavity have been studied using commercially available ray tracing software. The change in the cavity length was determined from the CFD model for several dye concentrations and pump powers. The results of the CFD model have been verified by published results and experimental results from our system. Our study shows that in the longitudinally pumped single mode laser change in the cavity length is a more dominant disturbance than thermal blooming. Our model is useful for the design of the dye cell.

  14. 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.

  15. Laser-dye ablation technique for removal of carious dentin and enamel

    NASA Astrophysics Data System (ADS)

    McNally-Heintzelman, Karen M.; Gillings, Barrie R.; Dawes, Judith M.

    1997-05-01

    A GaAlAs semiconductor diode laser operating at a wavelength of 796 nm has been sued in conjunction with Indocyanine Green (ICG) dye to ablate carious dentin and enamel from extracted human teeth. The laser-dye ablation technique offers selective ablation as it is controlled by the placement of the ICG dye. In contrast with other laser techniques, the risk of collateral thermal damage is substantially reduced. The diode laser is suitable for ordinary fiber delivery and is cheaper and more compact than the higher power CO2; Er:YAG, Nd:YAG and Argon lasers currently being used by researchers. This paper reports the ablation of dental caries in fifty extracted teeth with various laser diode powers and dye concentrations. The mass of material ablated, temperature rise in the pulp and surface temperature were measured. The ablation was found to be efficient with negligible thermal damage to surrounding tissue. At the same time average surface temperatures reached during ablation may be sufficient to sterilize the treated surface. Hardness measurements and scanning electron microscopy of the laser treated cavity surfaces show the new surfaces to be suitable for placement of a dental filling.

  16. 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.

  17. Mirrorless laser action from optically pumped dye-treated animal tissues

    NASA Astrophysics Data System (ADS)

    Siddique, Masood; Yang, Li.; Wang, Q. Z.; Alfano, R. R.

    1995-02-01

    Significant narrowing of the spectral and temporal profiles of emission radiation was observed from optically pumped chicken tissue and pig fat samples treated with rhodamine 640 dye solution. This narrowing of the emission response is attributed to mirrorless laser action from multiple scattering of radiation from within the excited dye regions of the animal tissue. These studies yield insight into the mechanisms of nonlinear optical interaction with continuously disordered heterogeneous active scattering structures of various sizes such as in animal tissues.

  18. Intensity and absorbed-power distribution in a cylindrical solar-pumped dye laser

    NASA Technical Reports Server (NTRS)

    Williams, M. D.

    1984-01-01

    The internal intensity and absorbed-power distribution of a simplified hypothetical dye laser of cylindrical geometry is calculated. Total absorbed power is also calculated and compared with laboratory measurements of lasing-threshold energy deposition in a dye cell to determine the suitability of solar radiation as a pump source or, alternatively, what modifications, if any, are necessary to the hypothetical system for solar pumping.

  19. Synchronous pumping of picosecond dye laser using high efficiency second harmonic generation from optical fibres

    NASA Technical Reports Server (NTRS)

    Lawandy, N. M.; Bernardin, J. P.; Macdonald, R. L.; Demouchy, G.

    1991-01-01

    The stable operation of a mode-locked dye laser synchronously pumped by the second harmonic of an Nd:YAG laser produced in an Nd codoped germanosilicate optical fiber is reported. The optical fiber preparation technique, which results in a second harmonic conversion efficiency of 2 percent, is described. This optical fiber SHG conversion efficiency is the highest reported to date using a continuous-wave mode-locked laser.

  20. 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)

  1. 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.

  2. Infrared Pulse-laser Long-path Absorption Measurement of Carbon Dioxide Using a Raman-shifted Dye Laser

    NASA Technical Reports Server (NTRS)

    Minato, Atsushi; Sugimoto, Nobuo; Sasano, Yasuhiro

    1992-01-01

    A pulsed laser source is effective in infrared laser long-path absorption measurements when the optical path length is very long or the reflection from a hard target is utilized, because higher signal-to-noise ratio is obtained in the detection of weak return signals. We have investigated the performance of a pulse-laser long-path absorption system using a hydrogen Raman shifter and a tunable dye laser pumped by a Nd:YAG laser, which generates second Stokes radiation in the 2-micron region.

  3. 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.

  4. Pulsed dye laser lithotripsy for treatment of urolithiasis in two geldings.

    PubMed

    Howard, R D; Pleasant, R S; May, K A

    1998-05-15

    Transendoscopic pulsed dye laser lithotripsy was effective in the treatment of calcium carbonate urothlithiasis in 2 adult geldings. Perineal urethrotomy provided convenient access for standing transendoscopic lithotripsy and evacuation of a large cystic calculus in one gelding. In the second horse, an obstructive urethral calculus was fragmented and removed by a transurethroscopic approach. Pulsed dye laser lithotriptor is effective in fragmentation of the most common form (calcium carbonate) of uroliths in horses and may be performed in standing horses with reduced surgical invasiveness and trauma to the urinary tract, compared with conventional approaches. The principle disadvantages include cost of the procedure, which is comparable to laparocystotomy, and the time delay required to make arrangements for use of the pulsed dye laser lithotriptor. PMID:9604033

  5. 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.

  6. Single-mode operation of a zig-zag dye laser

    SciTech Connect

    Mandl, A.; Klimek, D.E.

    1995-05-01

    The authors report single-mode operations of a laser pumped zig-zag dye laser for pulse length {gt}1{mu}s with beam quality close to the diffraction limit. A unique linear optical cavity using counter-propagating orthogonally polarized waves was used. Laser efficiency measurements performed with a stable cavity had outputs of greater than 1.7 J at 568 nm using Pyrromethene-567 dye. The intrinsic laser efficiency was 55% with a slope efficiency of 77%. Single-mode operation was achieved using an unstable resonator with intra-cavity etalons to control the free running modes of the cavity and seeding with a single-mode Kr-ion laser operating at 568 nm. Heterodyne measurements were used to determine that the bandwidth was near the transform limit with the frequency chirping at a rate {approximately}60 MHz/{mu}s. Far-field measurements of the beam quality indicated close to diffraction limited output.

  7. Chirp control of a single-mode, good beam quality, zigzag dye laser

    SciTech Connect

    Mandl, A.; Zavriyev, A.; Klimek, D.E.

    1997-03-01

    The authors report a substantial reduction of frequency chirp of a single-mode laser-pumped zigzag dye laser. A linear optical cavity using counterpropagating orthogonally polarized waves was injection-seeded at 568 nm and operated with a laser output of about 1 J. The chirp was controlled by an intracavity Pockels cell that was configured to add optical density at a rate which counterbalanced the decrease in optical density due to dye-solvent heating during the {approximately}1-{micro}s laser pulse. Heterodyne measurements were used to determine that the bandwidth was near the transform limit and chirp rate of {approximately}1 MHz/{micro}s. The beam quality of the laser was measured at 10 Hz as 1.7 XDL.

  8. Laser annealed composite titanium dioxide electrodes for dye-sensitized solar cells on glass and plastics

    NASA Astrophysics Data System (ADS)

    Pan, Heng; Ko, Seung Hwan; Misra, Nipun; Grigoropoulos, Costas P.

    2009-02-01

    We report a rapid and low temperature process for fabricating composite TiO2 electrodes for dye-sensitized solar cells on glass and plastics by in tandem spray deposition and laser annealing. A homogenized KrF excimer laser beam (248 nm) was used to layer-by-layer anneal spray deposited TiO2 nanoparticles. The produced TiO2 film is crack free and contains small particles (30 nm) mixed with different fractions of larger particles (100-200 nm) controlled by the applied laser fluence. Laser annealed double-layered structure is demonstrated for both doctor-blade deposited and spray-deposited electrodes and performance enhancement can be observed. The highest demonstrated all-laser-annealed cells utilizing ruthenium dye and liquid electrolyte showed power conversion efficiency of ˜3.8% under simulated illumination of 100 mW/cm2.

  9. 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.

  10. 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.

  11. Gain measurements in binary and ternary dye mixture solutions under nitrogen laser excitation

    NASA Astrophysics Data System (ADS)

    Sanghi, Sujata; Mohan, D.; Singh, R. D.

    1997-05-01

    Energy transfer studies in the case of binary [Coumarin 485 (C485) + Rhodamine 610 perchlorate (Rh 610)] and ternary [C440 + C485 + Rh610 perchlorate] dye mixture solutions in ethanol have been made and discussed through optical gain characteristics at various acceptor concentrations and pump powers of the N 2-laser. In case of binary mixtures, we observe that the optical gain of the acceptor dye (Rh610) improves and the threshold power required for lasing action decreases when donor dye (C485) is added. The concentration dependence of peak gain and peak lasing wavelength of the energy transfer dye laser (ETDL) has been studied. The results have also been compared with the optical gain characteristics of these dyes in single component solutions. The energy transfer rate constants ( KF, the Förster type non-radiative and KR, the radiative rate constants) and critical transfer radius ( Ro) have been calculated using a Stern-Volmer analysis of the pump power dependence of the gain. From the experimental results, we find that the dominant mechanism responsible for efficient excitation transfer in this bimixture is of a radiative nature. Further, the gain equation for a ternary dye mixture has been derived using the transfer rate constants for two different possible bimixtures; C440 + C485 and C485 + Rh610, which is helpful in obtaining the optimum concentration to be used in the ternary mixture for higher gains.

  12. Performance of a flashlamp-pumped solid state dye laser

    NASA Astrophysics Data System (ADS)

    Minnigh, Stephen W.; Pacheco, Dennis P.; Burke, James G.; Dunleavy, Paul J.; Aldag, Henry R.; Ehrlich, John J.

    1996-03-01

    This paper describes an ongoing study of dye-doped polymer materials as gain media in flashlamp-pumped systems. In this work, we have demonstrated 300 mJ/pulse at 0.4% energy efficiency using PM-597 in modified PMMA. The slope efficiency was maintained at 0.46%, except at the highest input energies. These results are quite comparable to those obtained for the same dye in liquid solution. Two important materials considerations in achieving these results are to keep the bulk transmission losses below 0.5%/cm, and to design the resonator in accord with the static as well as the dynamic lensing of the rod.

  13. 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.

  14. 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.

  15. Pulsed dye laser in the treatment of 325 calculi of the urinary tract.

    PubMed

    Gautier, J R; Leandri, P; Rossignol, G; Caissel, J; Quintens, H

    1990-01-01

    The pulsed dye laser (Candela) has been used from February 1988 to September 1989 in order to treat 325 stones in 278 patients. A total of 285 endoscopies has been performed. The pulsed laser has helped to achieve the fragmentation of 318 stones. Laser fragmentation has not induced any complication at all. The main failures can be attributed to the nature and shape of the stone. Thanks to the thin laser fiber, the use of small diameter ureteroscopes has increased the reliability of ureteroscopy. The use of this technique combined to extracorporeal shock wave lithotripsy (ESWL) has reduced the rate of open surgery for ureteral stones down to less than 1%. PMID:1976095

  16. Energy scaling and beam quality studies of a zigzag solid-state plastic dye laser

    SciTech Connect

    Mandl, A.; Zavriyev, A.; Klimek, D.E.

    1996-10-01

    Studies of the energy scaling and beam quality improvement of a long-pulse laser pumped solid-state dye laser using a unique new zigzag optical configuration are presented. A beam quality of 1.7 XDL was measured using an unstable optical cavity at a laser output of 200 mJ. Single pulse energies as high as 1 J have been achieved. The laser has been operated at 5 Hz with an average output of about 250 mJ for runs up to 200 pulses.

  17. New 8-amino-BODIPY derivatives: surpassing laser dyes at blue-edge wavelengths.

    PubMed

    Bañuelos, Jorge; Martín, Virginia; Gómez-Durán, C F Azael; Arroyo Córdoba, Ismael J; Peña-Cabrera, Eduardo; García-Moreno, Inmaculada; Costela, Ángel; Pérez-Ojeda, M Eugenia; Arbeloa, Teresa; López Arbeloa, Iñigo

    2011-06-20

    The development of highly efficient and stable blue-emitting dyes to overcome some of the most important shortcomings of available chromophores is of great technological importance for modern optical, analytical, electronic, and biological applications. Here, we report the design, synthesis and characterization of new tailor-made BODIPY dyes with efficient absorption and emission in the blue spectral region. The major challenge is the effective management of the electron-donor strength of the substitution pattern, in order to modulate the emission of these novel dyes over a wide spectral range (430-500 nm). A direct relationship between the electron-donor character of the substituent and the extension of the spectral hypsochromic shift is seen through the energy increase of the LUMO state. However, when the electron-donor character of the substituent is high enough, an intramolecular charge-transfer process appears to decrease the fluorescence ability of these dyes, especially in polar media. Some of the reported novel BODIPY dyes provide very high fluorescence quantum yields, close to unity, and large Stokes shifts, leading to highly efficient tunable dye lasers in the blue part of the spectrum; this so far remains an unexploited region with BODIPYs. In fact, under demanding transversal pumping conditions, the new dyes lase with unexpectedly high lasing efficiencies of up to 63 %, and also show high photostabilities, outperforming the laser action of other dyes considered as benchmarks in the same spectral region. Considering the easy synthetic protocol and the wide variety of possible substituents, we are confident that this strategy could be successfully extended for the development of efficient blue-edge emitting materials and devices, impelling biophotonic and optoelectronic applications. PMID:21547964

  18. Hair Dryer Use to Optimize Pulsed Dye Laser Treatment in Rosacea Patients

    PubMed Central

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

    2012-01-01

    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. PMID:22768356

  19. 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.}

  20. 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.

  1. Intracavity Dye-Laser Absorption Spectroscopy (IDLAS) for application to planetary molecules

    NASA Technical Reports Server (NTRS)

    Lang, Todd M.; Allen, John E., Jr.

    1990-01-01

    Time-resolved, quasi-continuous wave, intracavity dye-laser absorption spectroscopy is applied to the investigation of absolute absorption coefficients for vibrational-rotational overtone bands of water at visible wavelengths. Emphasis is placed on critical factors affecting detection sensitivity and data analysis. Typical generation-time dependent absorption spectra are given.

  2. 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.

  3. Functions of laser light, laser-absorbing dye, and immunoadjuvants in photodynamic immunotherapy

    NASA Astrophysics Data System (ADS)

    Chen, Wei R.; Liu, Hong; Bartels, Kenneth E.; Nordquist, Robert E.

    2000-10-01

    Photo Dynamic Immuno Therapy (PDIT) is a novel approach for treatment of metastatic tumors. It involves an intratumor administration of a laser-absorbing dye and an immunoadjuvant, followed by a non-invasive laser irradiation. Previous studies using a novel immunoadjuvant, glycated chitosan, showed the effect of the treatment on a metastatic breast tumor in rats, including the eradication of treated primary tumors, regression of untreated metastases, and the evidence of immune responses induced by the treatment. To further understand the mechanism of PDIT, tumor-bearing rats were treated by different combinations of the three PDIT components. The rat survival rates and profiles of primary and metastatic tumors, after treatment by individual component and different combinations of components, were analyzed. All the experimental groups without using immunoadjuvant showed none or little positive effect. The use of glycated chitosan, either by itself or in combination of other components, has showed that among the concentrations of 0.5%, 1% and 2%, glycated chitosan was most effective at 1% in PDIT. Another immunoadjuvant, incomplete Freund's adjuvant, was also used and the results were compared with that of using glycated chitosan. PDIT was applied to a different tumor model- Met-Lu, a prostatic tumor with lung metastases in male rats and the preliminary results are reported.

  4. 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

  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. 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

  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. Atomic-fluorescence analysis of materials using a lamp-pumped dye LZhI laser as an excitation source

    SciTech Connect

    Denisov, L.K.; Loshin, A.F.; Nikiforov, V.G.; Sterlyadkina, E.A.

    1987-12-01

    The use of frequency-tunable dye lasers in atomic-fluorescence analysis has made it possible to lower significantly the limits of detection for most elements. In this work the commercially produced lamp-pumped dye lasers of the type LZhI were used as the excitation source, which made it possible, first of all, to simplify the design of the atomic-fluorescence spectrometer by eliminating the frequency doubling of the laser radiation and, second, to study the analytical possibilities of commercially produced dye lasers with microsecond lasing. The authors studied solutions of sodium, barium, potassium, calcium, nickel, cobalt, copper, and molybdenum salts. These elements were chosen based on the fact that they have absorption lines with different degrees of intensity in the region of generation of the most efficient rhodamine 6G dye laser.

  9. 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.

  10. Embedding of fluorescent dyes into polyelectrolyte capsules for remote destruction of the capsule shell by laser irradiation

    NASA Astrophysics Data System (ADS)

    Marchenko, I. V.; Parakhonsky, G. V.; Bukreeva, T. V.; Plotnikov, G. S.; Baranov, A. N.; Saletsky, A. M.

    2010-02-01

    Polyelectrolyte capsules were modified by different types of fluorescent dyes and their optical properties were investigated. Three methods of encapsulation were used: dye adsorption onto the porous core, change of the solvent and embedding into the polyelectrolyte shell. Suspension of capsules with Rhodamine 6G molecules in the shell was irradiated by laser beam with wavelength corresponded with the absorption band for the dye molecule. Measurements of the capsules size distribution before and after laser irradiation showed that the capsules were destroyed by laser radiation.

  11. Embedding of fluorescent dyes into polyelectrolyte capsules for remote destruction of the capsule shell by laser irradiation

    NASA Astrophysics Data System (ADS)

    Marchenko, I. V.; Parakhonsky, G. V.; Bukreeva, T. V.; Plotnikov, G. S.; Baranov, A. N.; Saletsky, A. M.

    2009-10-01

    Polyelectrolyte capsules were modified by different types of fluorescent dyes and their optical properties were investigated. Three methods of encapsulation were used: dye adsorption onto the porous core, change of the solvent and embedding into the polyelectrolyte shell. Suspension of capsules with Rhodamine 6G molecules in the shell was irradiated by laser beam with wavelength corresponded with the absorption band for the dye molecule. Measurements of the capsules size distribution before and after laser irradiation showed that the capsules were destroyed by laser radiation.

  12. BRIEF COMMUNICATIONS: Dye-jet laser pumped by the second harmonic of a Q-switched and mode-locked YAG:Nd3+ laser

    NASA Astrophysics Data System (ADS)

    Golubev, V. A.; Goncharov, A. N.; Maĭorov, A. P.; Makukha, V. K.; Smirnov, Vitalii A.; Tarasov, V. M.

    1981-05-01

    A report is given of the operating parameters of a dye jet laser pumped by the second harmonic of a cw Q-switched mode-locked YAG:Nd3+ laser. The dye laser emitted a continuous train of 250 nsec pulses at a repetition frequency of 25 kHz or a sequence of ultrashort pulse trains. A Lyot filter was used to tune the emission wavelength in the range 560-630 nm.

  13. 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.

  14. 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)

  15. 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.

  16. 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.

  17. Red-green-blue laser emissions from dye-doped poly(vinyl alcohol) films.

    PubMed

    Yap, Seong-Shan; Siew, Wee-Ong; Tou, Teck-Yong; Ng, Seik-Weng

    2002-03-20

    A microscope slide acting as a passive waveguide was coated by three separate poly(vinyl alcohol) films that were doped with Coumarin 460, Disodium Fluorescein, and Rhodamine 640 perchlorate. On collinear pumping by a nitrogen laser, these dyes furnished primary red-green-blue laser emissions that were collected and waveguided by the microscope slide but exited from both ends. Frosting the waveguide exit introduced light scattering at the glass-air interface and spatially overlaid the red-green-blue laser emissions that emerged as a uniform white-light beam. PMID:11921803

  18. A tunable dye laser with a CaMoO4 acoustooptical filter

    NASA Astrophysics Data System (ADS)

    Mazur, M. M.; Makhmudov, Kh. M.; Pustovoit, V. I.

    1988-04-01

    A new optical scheme is proposed and an electronically tunable laser with a CaMoO4 acoustooptical filter (AOF) used as the dispersing element is experimentally tested. For rhodamine C dye, an emission wavelength tuning range of about 40 nm with a line width of 0.3 nm is obtained. Single and dual frequency operation is described. It is shown that the CaMoO4 AOF allows for laser operation with a driving RF power of 1 W, making it possible to use the laser in the CW mode.

  19. 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.

  20. 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.

  1. Update on flashlamp pumped pulsed dye laser treatment for port wine stains (capillary malformation) patients

    PubMed Central

    Hsiao, Yen-Chang; Chang, Cheng-Jen

    2011-01-01

    Background and Aims: Currently, the method of choice for the treatment of port-wine stains is laser photocoagulation. Because of evolving treatment options, it is no longer enough for port-wine stains merely to be lightened through laser treatment. The best course of management consists of the most appropriate laser that will produce the most complete clearing of a lesion in the fewest treatment sessions with the least morbidity. The goal is generally accomplished with the use of yellow-light lasers. Materials (Subjects) and Methods: Absorption of laser energy by melanin causes localized heating in the epidermis, which may, if not controlled, produce permanent complications such as hypertrophic scarring or dyspigmentation. Refinements of the results can be achieved by using the flashlamp-pumped pulsed dye laser (FLPDL) in conjunction with the cryogen spray cooling (CSC) system. In our related studies, the infrared thermal image instrument is used for doctors in determining the optimum laser light dosage and preventing the side effects caused by FLPDL. Topic application of angiogenesis inhibitor (Imiquimod) in conjunction with pulsed dye laser treatment for the PWS patients has been assessed for improvement of FLPDL treatment. Results: We present the clinical effect of FLPDL, and the efficacy and safety of cooled laser treatment of PWS birthmarks. Our clinical outcome in the laser treatment of patients with PWS has been achieved to maximize thermal impact on targeted vessels, while minimizing adverse complications. Conclusions: CSC in conjunction with FLPDL can improve the treatment of PWS. The infrared image instrument is helpful for doctors in determining the optimum laser light dosage. Topic application of angiogenesis inhibitor (Imiquimod) in conjunction with laser treatment for the PWS patients is promising in the near future. PMID:24155536

  2. Effect of. gamma. -cyclodextrin on the intramolecular charge transfer processes in aminocoumarin laser dyes

    SciTech Connect

    Nag, A.; Chakrabarty, T.; Bhattacharyya, K. )

    1990-05-17

    Steady-state and time-resolved studies on the emission properties of three 7-(diethylamino)coumarin laser dyes (I-III) in aqueous {gamma}-cyclodextrin ({gamma}-CD) solutions are reported. On addition of {gamma}-CD, fluorescence maxima of all the three dyes shift to higher energy, with a huge enhancement of the yield of intramolecular charge transfer (ICT) emission for the flexible ones (I and II) and a very slight enhancement for the rigid analogue III. The results are explained in terms of the concept of polarity-dependent twisted ICT rates. It is proposed that twisted ICT, the main nonradiative process in the excited ICT states of these dyes, is severely restricted inside the {gamma}-cyclodextrin cavity because of the reduced polarity. This is responsible for the enhancement of fluorescence from the ICT state.

  3. 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.

  4. FRET-assisted laser emission in colloidal suspensions of dye-doped latex nanoparticles

    NASA Astrophysics Data System (ADS)

    Cerdán, Luis; Enciso, Eduardo; Martín, Virginia; Bañuelos, Jorge; López-Arbeloa, Iñigo; Costela, Angel; García-Moreno, Inmaculada

    2012-09-01

    The use of commercial long-wavelength (>650 nm) laser dyes in many biophotonic applications has several important limitations, including low absorption at the standard pump wavelength (532 nm) and poor photostability. Here, we demonstrate that the use of Förster type (FRET) energy transfer can overcome these problems to enable efficient, stable near-infrared lasing in a colloidal suspension of latex nanoparticles containing a mixture of Rhodamine 6G and Nile Blue dyes. Experimental and theoretical analyses of the photophysics suggest that the dominant energy transfer mechanism is Förster type via dipole-dipole coupling, and also reveal an unexpected core/shell morphology in the dye-doped nanoparticles. FRET-assisted incoherent random lasing is also demonstrated in solid samples obtained by evaporation of colloidal suspensions.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. Electron microscopic study on black pig skin irradiated with pulsed dye laser (504 nm)

    NASA Astrophysics Data System (ADS)

    Yasuda, Yukio; Tan, Oon T.; Kurban, Amal K.; Tsukada, Sadao

    1991-06-01

    Selective damage of epidermal pigment cells induced by 504 nm pulsed dye laser at different pulse durations and fluence on black pig skin was examined electron microscopically. Epidermal melanosomes were satisfactorily disrupted at shorter pulse duration (100 ns). Epidermal blister formation and necrosis were seen at 2 days postirradiation, and reepithelization was evident at 7 days postirradiation in all specimens. Repigmentation was evident 21 to 56 days after irradiation. Histological pigmentary incontinence was evident at 2 days and persisted until 56 days postirradiation. This phenomenon was observed more frequently in skin exposed to longer pulse duration and at low fluences. Optimal parameters required to induce epidermal melanosome disruption using the 504 nm pulsed dye laser will be discussed.

  10. Measuring the dispersion curve of a PMMA-fibre optic cable using a dye laser

    NASA Astrophysics Data System (ADS)

    Zorba, Serkan; Farah, Constantine; Pant, Ravi

    2010-11-01

    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 the other coupled to the optical fibre cable at the end of which there is another photodetector. The difference in time of arrival at the detectors is used to compute the speed of light in the fibre for a given colour. In addition to a pedagogically simple and intuitive demonstration of the measurement of index of refraction, the use of a long fibre eliminates the need to direct the dangerous UV/visible laser pulse beam across a classroom, as is usually done in similar experiments. Ways to avoid systematic errors and other technical pitfalls—such as ringing oscillations—are presented.

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

    NASA Technical Reports Server (NTRS)

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

    1986-01-01

    Raman conversion efficiency and line broadening are reported for Stokes operation at 720 and 940 nm, with hydrogen and deuterium as the Raman source, and using an Nd:YAG pumped Quanta-Ray PDL-2 dye laser. The dye laser linewidth is 0.2/cm (FWHM) with the grating alone as an intracavity element, and the conversion efficiency at 400 psi was found to be 40 and 20 percent for outputs of 720 and 940 nm, respectively. Pressure broadening coefficients of (9.2 + or - 0.9) x 10 to the -5th per cm/psi for hydrogen, and 7.7 x 10 to the -5th per cm/psi for deuterium, were obtained in good agreement with previous results. The linewidth at the first Stokes wavelength was shown to be determined by pressure broadening in the Raman medium.

  12. Blue laser dye spectroscopic properties in solgel inorganic-organic hybrid films.

    PubMed

    Saraidarov, Tsiala; Reisfeld, Renata; Kazes, Miri; Banin, Uri

    2006-02-01

    A blue solid-state laser material based on 4,4' dibenzyl carbamido stilbene-2,2' disulfonic acid incorporated into solgel zirconia and inorganic-organic hybrid matrices is presented. The absorption maxima of the dye in various matrices are around 339-361 nm, and the broad fluorescence peaks are at 411-413 nm. Optical gain measurements using the variable stripe method show amplified spontaneous emission peaking at 437 nm. PMID:16480207

  13. Blue laser dye spectroscopic properties in solgel inorganic-organic hybrid films

    NASA Astrophysics Data System (ADS)

    Saraidarov, Tsiala; Reisfeld, Renata; Kazes, Miri; Banin, Uri

    2006-02-01

    A blue solid-state laser material based on 4,4‧ dibenzyl carbamido stilbene-2,2‧ disulfonic acid incorporated into solgel zirconia and inorganic-organic hybrid matrices is presented. The absorption maxima of the dye in various matrices are around 339-361 nm, and the broad fluorescence peaks are at 411-413 nm. Optical gain measurements using the variable stripe method show amplified spontaneous emission peaking at 437 nm.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

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

    NASA Astrophysics Data System (ADS)

    Chandrahalim, Hengky; Fan, Xudong

    2015-12-01

    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.

  19. 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

  20. 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

  1. Dynamic operations of a dye laser with a saturable absorber: pumping anisotropy and orientational relaxation

    NASA Astrophysics Data System (ADS)

    Gaisenok, V. A.; Krylov, G. G.; Sergeyev, S. V.

    1994-04-01

    Coupled oscillators nonlinear dynamics was found for a dye laser with a saturable absorber and polarized pumping. It has been shown that two coupled cross-linearly polarized modes demonstrate the Bar-Eli effect, when excitation conditions for them are different. As a result, output energy of laser emission stops oscillating and stabilize at a constant steady state. When excitation conditions for them are the same, a new type of asymmetrical auto-oscillations for two modes arises. In addition it was emphasized that orientational relaxation processes (radiationless energy transfer or Brownian rotation of molecules) in an active medium transform asymmetrical auto-oscillations to symmetrical ones.

  2. 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.

  3. Solid-state dye laser with modified poly(methyl methacrylate)-doped active elements

    NASA Astrophysics Data System (ADS)

    Maslyukov, A.; Sokolov, S.; Kaivola, M.; Nyholm, K.; Popov, S.

    1995-03-01

    Laser generation with modified poly(methyl methacrylate) (MPMMA)-doped matrices with several different types of Rhodamine-based dyes was obtained. Pumping with a frequency-doubled Q-switched Nd:YAG laser was used. During the experiments, high conversion efficiency was achieved. The strong nonlinear dependence of the operating lifetime and the conversion efficiency of material tested on the pump-pulse-repetition rate was observed. Possible mechanisms responsible for the conversion-efficiency drop and the useful lifetime of the material are discussed.

  4. 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.

  5. 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.

  6. Optimization of a Raman shifted dye laser system for DIAL applications

    NASA Technical Reports Server (NTRS)

    Singh, Upendra N.; Chu, Zhiping; Mahon, Rita; Wilkerson, Thomas D.

    1990-01-01

    An efficient Raman shifted dye laser system that generates tunable radiation at 765 and 940 nm with a bandwidth of 0.03/cm is described. Operating a Raman cell at hydrogen pressure below 14 atm, optimum first Stokes energy conversions of 45 percent and of 37 percent at 765 and 940 nm, respectively, were recorded. Optical depth measurements made at the centers of twenty-five absorption lines in the P branch of the oxygen A band imply a high spectral purity for both the laser and the Raman shifted radiation, and thus indicate the feasibility of using the stimulated Raman scattered radiation for differential absorption lidar (DIAL) measurements.

  7. Combined pulsed dye and CO2 lasers in the treatment of angiolymphoid hyperplasia with eosinophilia.

    PubMed

    Sagi, Lior; Halachmi, Shlomit; Levi, Assi; Amitai, Dan Ben; Enk, Claes D; Lapidoth, Moshe

    2016-08-01

    Angiolymphoid hyperplasia with eosinophilia (ALHE) is an uncommon dermatosis of unknown etiology that manifests as characteristic red nodules and papules with a predilection for the scalp and periauricular region. Treatment is required for both esthetic and functional reasons, as lesions may ulcerate and bleed. Many treatment approaches have been reported, including excision, systemic medical approaches, topical or intralesional therapies, and non-invasive modalities including cryotherapy, electrosurgery, and laser. Treatments have exhibited variable efficacy, and the recurrence rate is 100 %. We report the combination of pulsed dye laser and CO2 laser in the treatment of ALHE in 14 patients. All patients exhibited clinical response after a mean of 2.4 ± 0.4 treatment sessions. The clinical efficacy of the combined treatment, together with its well-tolerated nature, render the use of pulsed dye laser in combination with CO2 laser, a viable treatment for debulking ALHE lesions. Ongoing maintenance treatments are needed to due to the high degree of relapse. PMID:27184154

  8. 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.

  9. Spontaneous emission and oscillation in a planar microcavity dye laser

    NASA Astrophysics Data System (ADS)

    Osuge, Michihiro; Ujihara, Kikuo

    1994-09-01

    Characteristics of a planar microcavity laser using rhodamine 6G with pulsed excitation is studied. Theoretical aspects of controlled spontaneous emission and oscillation in a planar microcavity laser are discussed. The measured spectrum and the angular divergence of spontaneous emission below threshold are in good agreement with theory. The angular divergence yields the radius of the cavity quasimode. The spontaneous emission coupling ratio obtained from the measured input-output characteristics is in reasonable agreement with the theoretical value. The expression for the coupling ratio derived for a Fabry-Perot-type microcavity is shown to be essentially equal to that of a closed cavity or guided mode cavity derived by Yamamoto, Machida, and Bjoerk (1991). The observed spectral behavior near the threshold approximately follows the Schawlow-Townes formula, but for a limited range of output power. The observed spectrum and divergence above threshold indicate incoherence much worse than the Schawlow-Townes limit.

  10. The pulsed dye laser versus the Q-switched Nd:YAG laser in laser-induced shock-wave lithotripsy.

    PubMed

    Thomas, S; Pensel, J; Engelhardt, R; Meyer, W; Hofstetter, A G

    1988-01-01

    To date, there are two fairly well-established alternatives for laser-induced shock-wave lithotripsy in clinical practice. The Q-switched Nd:YAG laser is distinguished by the high-stone selectivity of its coupler systems. The necessity of a coupler system and its fairly small conversion rate of light energy into mechanical energy present serious drawbacks. Furthermore, the minimal outer diameter of the transmission system is 1.8 mm. The pulsed-dye laser can be used with a highly flexible and uncomplicated 200-micron fiber. However, the laser system itself is more complicated than the Q-switched Nd:YAG laser and requires a great deal of maintenance. Biological evaluation of damage caused by direct irradiation shows that both laser systems produce minor damage of different degrees. YAG laser lithotripsy with the optomechanical coupler was assessed in 31 patients with ureteral calculi. The instability and limited effectiveness of the fiber application system necessitated auxiliary lithotripsy methods in 14 cases. Dye-laser lithotripsy is currently being tested in clinical application. Further development, such as systems for blind application or electronic feedback mechanisms to limit adverse tissue effects, have yet to be optimized. Nevertheless, laser-induced shock-wave lithotripsy has the potential to become a standard procedure in the endourologic management of stone disease. PMID:2902500