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1

Dye laser pumped atomic iodine laser  

Microsoft Academic Search

Lasing has been demonstrated on the 2P1\\/2-2P3\\/2 transition in atomic iodine by optically pumping I2 vapor to dissociation with a flashlamp-pumped tunable dye laser. Lasing at 1.315 mu has been observed for pump wavelengths from 5010 to 4930 A˚. The device holds promise as a rapidly pulsed gain diagnostic for existing or future iodine systems.

S. J. Davis

1978-01-01

2

Dye laser pumped atomic iodine laser  

Microsoft Academic Search

Lasing has been demonstrated on the 2P1\\/2–2P3\\/2 transition in atomic iodine by optically pumping I2 vapor to dissociation with a flashlamp-pumped tunable dye laser. Lasing at 1.315 ? has been observed for pump wavelengths from 5010 to 4930 A?. The device holds promise as a rapidly pulsed gain diagnostic for existing or future iodine systems.

S. J. Davis

1978-01-01

3

Excimer Pumped Pulsed Tunable Dye Laser  

NASA Astrophysics Data System (ADS)

It has been recently shown and reported for the first time at this meeting, that Excimer pumping of a single-mode, short-cavity, grazing-incidence, longitudinally-pumped pulsed dye laser is feasible. In this paper the key concepts upon which this latest development is based are presented and are in a somewhat unusual form. This manuscript describes five specific dye laser examples. The five examples represent a progression from the simplest type of dye laser to the single-mode version mentioned above. The examples thus serve as a tutorial introduction to potential users of dye lasers. The article is organized into five sections or STEPS, each of which describes a different pulsed dye laser. Since the subtle points about dye lasers are best appreciated only after one actually attempts to build a working model, a PROCEDURES category is included in which details about the construction of the particular form of laser are given. As one reads through this category, think of it as looking over the shoulder of the laser builder. The NOTES category which follows is a brief but essential discussion explaining why various components and procedures are used, as well as how laser performance specifications are obtained. This subsection can he viewed as a discussion with the laser builder concerning the reasons for specific actions and choices made in the assembly of the example laser. The last category contains COMMENTS which provide additional related information pertaining to the example laser that goes beyond the earlier annotated discussion. If you like, these are the narrator's comments. At the end of the article, after the five sequential forms of the laser have been presented, there is a brief summation.

Littman, Michael G.

1988-06-01

4

Near-IR dye laser for diode-pumped operation  

SciTech Connect

A dye laser pumped by AlGaInP laser diodes produced efficient, low threshold operation at wavelengths between 740 and 800 nm. Rhodamine 700, oxazine 750, DOTCI and oxazine 1 dyes were demonstrated. Optical conversion efficiencies approaching 50% and output power as high as 361 mW were obtained when pumping with a DCM-based dye laser. Parametric variations of the pump power and wavelength were performed over the range of 615 nm to 690 nm to provide a more complete characterization of the dye laser.

Scheps, R. [Naval Command, Control and Ocean Surveillance Center, San Diego, CA (United States). RDT and E Div.] [Naval Command, Control and Ocean Surveillance Center, San Diego, CA (United States). RDT and E Div.

1995-01-01

5

Passive apparatus for stabilizing a flashlamp-pumped dye laser  

SciTech Connect

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.

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

1986-04-29

6

High average power excimer laser-pumped dye oscillators  

SciTech Connect

The design, construction, and testing of a high-average-power excimer laser-pumped dye oscillator is described. The system is designed to produce up to 75 watts of average power in the near uv at a pulse repetition rate of 500 Hz. 8 figs.

Tennant, R.A.; Whitehead, M.C.; Tallman, C.R.; Basinger, R.W.

1988-01-01

7

Flashlamp-pumped mode-locked dye lasers  

NASA Astrophysics Data System (ADS)

Recent developments in the production of tunable picosecond pulses by means of flashlamp-pumped mode-locked dye lasers are reviewed. Particular attention is paid to an extension of the passive dye laser mode-locking technique based on the loss modulation of the gain of a secondary oscillator by means of the pulse train of a master oscillator. The resulting two trains of independently tunable picosecond pulses can be used to monitor a transient species by an excite-probe experiment with one shot only.

Schneider, S.

1980-11-01

8

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

NASA Technical Reports Server (NTRS)

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.

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

1975-01-01

9

A performance analysis and characterization of the Lumonics, Inc. HyperDYE-300 laser pumped dye laser  

NASA Astrophysics Data System (ADS)

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.

Taylor, Travis S.; Davenport, Wayne E.; Ehrlich, John J.

1990-07-01

10

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

Microsoft Academic Search

The design and development of an efficient high average power dye laser oscillator-amplifier system developed at the Laser & Plasma Technology Division, Bhabha Atomic Research Center, 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 dye laser oscillator

Sunita Singh; Kamalesh Dasgupta; Sasi Kumar; K. G. Manohar; L. G. Nair; U. K. Chatterjee

1994-01-01

11

Dye laser pumped by radiation from a cw YAG:Nd/sup 3 +/ laser with intracavity second harmonic generation  

SciTech Connect

An experimental study was made of lasing in dyes pumped by radiation from a cw YAG:Nd/sup 3 +/ laser with intracavity second harmonic generation in an LiIO/sub 3/ crystal. The parameters of the tunable dye laser radiation were not inferior to those obtained by pumping dyes with high-power argon laser radiation.

Konvisar, P.G.; Lokhnygin, V.D.; Rustamov, S.R.; Fomichev, A.A.

1982-08-01

12

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

NASA Astrophysics Data System (ADS)

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.

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

1992-08-01

13

ACTIVE MEDIA: Anomalous dependence of the lasing parameters of dye solutions on the spectrum of microsecond pump laser pulses  

Microsoft Academic Search

The anomalous dependence of the lasing parameters of ethanol solutions of coumarin, rhodamine, oxazine, and laser dyes of other classes on the spectrum of microsecond pump laser pulses is found. The dependence is determined by the shape of the induced singlet --- singlet absorption spectra and absorption spectra of short-lived photoproducts. The elucidation of the influence of these factors makes

V. V. Tarkovsky; V. Yu Kurstak; S. S. Anufrik

2003-01-01

14

Excimer-laser pumped infrared dye laser at 907-1023 nm  

Microsoft Academic Search

Infrared laser operation has been achieved in the range 907-1023 nm by pumping LDS 925 (Styryl 13) with the ultraviolet output of a XeCl excimer laser at 308 nm. Despite conversion efficiency of 8.3% at 960 nm is easily achived.

L. A. Bloomfield

1989-01-01

15

Monolithic dye laser amplifier  

DOEpatents

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.

Kuklo, Thomas C. (Ripon, CA)

1993-01-01

16

Monolithic dye laser amplifier  

DOEpatents

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.

Kuklo, T.C.

1993-03-30

17

Beam profile of the flashlamp pumped pulsed dye laser: support for overlap of exposure spots.  

PubMed

The degree to which individual practitioners overlap exposure spots of the flashlamp pumped pulsed dye laser when treating large vascular lesions appears to be a matter of personal preference. There are few data to support one approach over another. We have measured the beam profile of this laser at two different energy fluences using a photodiode and a digitizing storage oscilloscope. Results show that for each energy fluence, the beam intensity decreases from the center to the outside rim of the beam. A plot of beam intensity versus the radius of the treatment field approaches a truncated normal distribution with a full width at half-maximum of 4.7-4.8 mm. These results help explain why clinical overlap of exposure spots can be safely undertaken and provide a rationale for recommendations concerning the degree of overlap needed to expedite treatment while still minimizing adverse reactions. PMID:7830473

Dinehart, S M; Flock, S; Waner, M

1994-01-01

18

Influence of pump repetition rate on dye photostability in a solid-state dye laser with a polymeric gain medium  

NASA Astrophysics Data System (ADS)

The influence of pump repetition rate on the conversion efficiency and photostability of a polymeric gain material doped with the dye Rh6G is studied. The effect of heating of the host polymeric matrix due to the high pump repetition rate in the stimulation of chemical reactions, leading to dye photodestruction, is discussed. Such heating appears to influence the polymeric gain material photostability considerably. The increase of the diffusion rate of the dye due to weak heat dissipation in the gain material and heating of the gain medium, consequently resulting in the migration of dye molecules from a pumped volume, is reported and discussed for the first time. The role of additives with low molecular weights in the polymeric matrix in increasing the photostability of the polymeric gain material is discussed.

Popov, S.

1998-11-01

19

The use of caffeine as a liquid filter in coaxial flashlamp pumped dye lasers  

Microsoft Academic Search

Problems of cooling and preserving laser dyes can be solved by adding caffeine or other suitable filter materials to the cooling water in coaxial systems. Systems using dissolved filter chemicals are cheap, versatile and assist in heat removal from coaxial type dye lasers.

John Calkins; Ed Colley; John Hazle

1982-01-01

20

Direct solar-pumped iodine laser amplifier  

Microsoft Academic Search

In order to evaluate the feasibility of the solar pumped dye laser, the parametric study of a dye laser amplifier pumped by a solar simulator and flashlamp was carried out, and the amplifier gains were measured at various pump beam irradiances on the dye cell. Rhodamine 6G was considered as a candidate for the solar pumped laser because of its

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

1986-01-01

21

Dye laser with rotating wedge alignment seruo  

SciTech Connect

A laser-pumped laser system is disclosed, such as a dye laser which is optically pumped by an argon ion laser. An improved servo system is provided for maintaining relative alignment of the pump laser beam with respect to the dye laser cavity. This is accomplished by rotating the pump beam such that the beam defines a conical surface, by means such as an optically-transmissive rotating wedge. Such rotation provides dithering along two orthogonal axes, which provides the necessary control information to maintain pump beam alignment.

Witte, K. G.; Johnston Jr., T. F.

1985-04-30

22

Dye laser amplifier  

DOEpatents

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.

Moses, Edward I. (Livermore, CA)

1992-01-01

23

Laser action of dyes in gelatin  

Microsoft Academic Search

High-gain directional stimulated emission has been observed for a number of dyes in gelatin with pumping by a nitrogen laser or a liquid dye laser. For some dyes the gel is made with water and gelatin; for others a detergent must be added or glycerin used instead of water.

T. Hansch; M. Pernier; A. Schawlow

1971-01-01

24

A micro-cavity fluidic dye laser  

Microsoft Academic Search

We have successfully fabricated and characterized a micro-cavity fluidic dye laser with metallic mirrors, which can be integrated with other microfluidic systems without adding further process steps. A laser dye solution is pumped through a microfluidic channel containing the laser cavity. The microfluidic channel structure, which is formed in SU-8 photoresist, is sandwiched between Pyrex glass wafers, bonded together at

Bjarne Helbo; Anders Kristensen; Aric Menon

2003-01-01

25

Direct solar-pumped iodine laser amplifier  

NASA Technical Reports Server (NTRS)

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

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

1986-01-01

26

Optically pumped iodine monofluoride laser  

SciTech Connect

This invention comprises an optically pumped iodine monofluoride laser operating on the B/sup 3/ ..pi.. (O/sup +/) ..-->.. X /SUP S/ ..sigma.. /sup +/ SYSTEM. Ground state IF was produced by the reaction beI/sub 2/ and F/sub 2/ in an optical cavity which was subsequently optically pumped with a high e00007600 broadband dye laser to produce lasing energy. 00007700

Davis, S. T.; Hanko, L.

1984-12-11

27

Direct solar-pumped iodine laser amplifier  

NASA Technical Reports Server (NTRS)

This semiannual progress report covers the period from April 1, 1985 to Sept. 30, 1985 under NASA grant NAS1-441 entitled direct solar pumped iodine laser amplifier. During this period the parametric studies of the iodine laser oscillator pumped by a Vortek simulator was carried out before the amplifier studies. The amplifier studies are postponed to the extended period following completion of the parametric studies. In addition, the kinetic modeling of a solar pumped iodine laser amplifier, and the experimental work for a solar pumped dye laser amplifier are in progress. This report contains three parts: (1) the radiation characteristics of solar simulator and the parametric characteristics of photodissociation iodine laser continuously pumped by a Vortek solar simulator; (2) kinetic modeling of a solar pumped iodine laser amplifier; and (3) the study of the dye laser amplifier pumped by a Tamarack solar simulator.

Han, K. S.

1985-01-01

28

Characteristics of a Broadband Dye Laser Using Pyrromethene and Rhodamine Dyes  

NASA Technical Reports Server (NTRS)

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.

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

2011-01-01

29

Dye laser traveling wave amplifier  

NASA Technical Reports Server (NTRS)

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.

Davidson, F.; Hohman, J.

1985-01-01

30

Solid state dye laser for medical applications  

NASA Astrophysics Data System (ADS)

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.

Aldag, Henry R.

1994-06-01

31

Dye laser tuner  

SciTech Connect

A laser of the kind in which the lasing medium is a free flowing dye stream incorporates a means of tuning the output wave length of the laser, this means being in the form of a wedged birefringent plate which is driven in a linear mode by a linear translator so that the thickness of the birefringent plate traversed by the intracavity beam of laser light may be varied.

Arthurs, E.G.; Purdie, A.F.

1980-11-11

32

Characteristics of xenon-lamp pumped pyrromethene 567-doped dye laser based on polymethylmethacrylater  

NASA Astrophysics Data System (ADS)

The solid-state medium containing pyrromethene 567 (PM567) in a polymethylmethacrylate polymer host is shown to lase under the flash lamp excitation. The experimental setup is an ordinary industrial product without special design. The bulk transmission losses, the output energy, and the other lasing properties are compared. The medium with the lowest transmission loss, measured to be 0.392 %/cm at 633 nm, gives a laser output of 130 mJ with a slope efficiency of 0.082%.

Wang, Lei; Chen, De-Ying; Xia, Yuan-Qin; Fan, Rong-Wei; He, Wei-Ming

2012-01-01

33

Direct solar-pumped iodine laser amplifier. Semiannual progress report, 1 March31 August 1986  

Microsoft Academic Search

In order to evaluate the feasibility of the solar pumped dye laser, the parametric study of a dye laser amplifier pumped by a solar simulator and flashlamp was carried out, and the amplifier gains were measured at various pump beam irradiances on the dye cell. Rhodamine 6G was considered as a candidate for the solar pumped laser because of its

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

1986-01-01

34

Tunability of optofluidic distributed feedback dye lasers  

NASA Astrophysics Data System (ADS)

We investigate the tunability of optofluidic distributed feedback (DFB) dye lasers. The lasers rely on light-confinement in a nano-structured polymer film where an array of nanofluidic channels constitutes a third order Bragg grating DFB laser resonator with a central phase-shift. The lasers are operated by filling the DFB laser resonator with a dye solution by capillary action and optical pumping with a frequency doubled Nd:YAG laser. The low reflection order of the DFB laser resonator yields low out-of-plane scattering losses as well as a large free spectral range (FSR), and low threshold fluences down to ~7 µJ/mm2 are observed. The large FSR facilitates wavelength tuning over the full gain spectrum of the chosen laser dye and we demonstrate 45 nm tunability using a single laser dye by changing the grating period and dye solution refractive index. The lasers are straight-forward to integrate on lab-on-a-chip microsystems, e.g. for novel sensor concepts, where coherent light in the visible range is desired.

Gersborg-Hansen, Morten; Kristensen, Anders

2007-01-01

35

Water soluble laser dyes  

DOEpatents

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.

Hammond, Peter R. (Livermore, CA); Feeman, James F. (Wyomissing, PA); Field, George F. (Santa Ana, CA)

1998-01-01

36

Water soluble laser dyes  

DOEpatents

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.

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

1998-08-11

37

Optofluidic ring resonator dye lasers  

Microsoft Academic Search

We overview the recent progress on optofluidic ring resonator (OFRR) dye lasers developed in our research group. The fluidics and laser cavity design can be divided into three categories: capillary optofluidic ring resonator (COFRR), integrated cylindrical optofluidic ring resonator (ICOFRR), and coupled optofluidic ring resonator (CpOFRR). The COFRR dye laser is based on a micro-sized glass capillary with a wall

Yuze Sun; Jonathan D. Suter; Xudong Fan

2010-01-01

38

Dye Photodestruction in a Solid-State Dye Laser with a Polymeric Gain Medium  

NASA Astrophysics Data System (ADS)

The process of dye photodestruction in a solid-state dye laser is studied, and implemented is a polymeric gain medium doped with a strongly concentrated dye. The behavior of the conversion efficiency in the polymeric gain medium pumped with different laser-pulse repetition rates and the process of dye photobleaching are analyzed. The contribution of the heating of the host material into the dye molecules deactivation is discussed. The negative effect of high dye concentration on the dye stability under a high pump repetition rate is reported and analyzed for the first time to my knowledge. A comparison of the present results with recently published data demonstrates the major role of photodestruction, rather than direct thermodestruction, in the dye stability of the solid-state gain medium. The role of additives with low molecular weights in the polymeric matrix, for increasing the stability of the gain material, is discussed.

Popov, Sergei

1998-09-01

39

Solid state dye lasers with scattering feedback  

NASA Astrophysics Data System (ADS)

Over the last decade, significant advances have been made toward the development of practical, tunable solid state dye lasers, which resulted in improved lasing efficiency with reduced dye photodegradation. To achieve this goal, a “chemical” approach was followed, where attention was focused onto the particular dye/host interaction and compatibility, specifically choosing already existing hosts for a given dye, synthesizing new dyes and/or matrices, or chemically modifying existing ones. Nevertheless, this approach was limited by a single fact learnt from the experience: there is no universal matrix which optimizes the efficiency and photostability of all dyes. This limitation could be overcome by following a “physical” approach, where the emission properties of the active medium are tailored by means of physical and structural modifications of the dye host. Following this approach, in this paper recent theoretical and experimental work is reviewed where it is demonstrated that following a simultaneous “physical” and “chemical” approach to tailor the emission properties of the host materials for solid state dye lasers, may lead, under specific circumstances, to the improvement of both the laser efficiency and photostability. In particular, it is demonstrated that optical scattering is not always detrimental either to conventional bulk lasers (laser rods or colloidal suspensions) or to integrated devices, but may give place, on the contrary, to dramatic improvements in the laser operation of organic (hybrid) laser rods, and to alternative ways of obtaining laser light from integrated devices based on the phenomenon of coherent random lasing, where feedback is provided by light scattering in an appropriate medium, without the need to manufacture complex periodic structures in the substrate. The processing and pumping flexibility of these materials, together with their low cost and capability of efficient emission across the whole visible spectrum makes them very attractive for the fabrication and development of coherent light sources suitable for integration in optoelectronic and disposable spectroscopic and sensing devices.

Costela, A.; Cerdán, L.; García-Moreno, I.

2013-11-01

40

Optofluidic Distributed Feedback Dye Lasers  

Microsoft Academic Search

We review our recent work on poly(dimethylsiloxane) (PDMS)-based optofluidic dye lasers using a guided wave distributed feedback (DFB) cavity. We show experimental results of single-mode operation, an integrated laser array, multiple color dye lasing, mechanical and fluidic tuning, and monolithic integration with microfluidic circuits. Potential applications and future directions are discussed

Zhenyu Li; Demetri Psaltis

2007-01-01

41

Fusion reactor pumped laser  

DOEpatents

A nuclear pumped laser capable of producing long pulses of very high power laser radiation is provided. A toroidal fusion reactor provides energetic neutrons which are slowed down by a moderator. The moderated neutrons are converted to energetic particles capable of pumping a lasing medium. The lasing medium is housed in an annular cell surrounding the reactor. The cell includes an annular reflecting mirror at the bottom and an annular output window at the top. A neutron reflector is disposed around the cell to reflect escaping neutrons back into the cell. The laser radiation from the annular window is focused onto a beam compactor which generates a single coherent output laser beam.

Jassby, Daniel L. (Princeton, NJ)

1988-01-01

42

Model of the para-terphenyl dye laser  

SciTech Connect

A theoretical model for a Para-Terphenyl dye laser pumped by an excimer laser has been developed. A new set of reaction-rate coefficients for Para-Terphenyl has been established. The problem of spontaneous emission in a dye has been solved analytically. The numerical solutions of the laser equations agree closely with the experimental results reported in the literature. Use of our model resulted in the achievement of higher efficiencies and narrower linewidths than those previously reported.

Fournier, G.

1981-11-01

43

SU8 BASED SOLID STATE DYE LASERS FOR LAB-ON-A-CHIP MICROSYSTEMS  

Microsoft Academic Search

We present a new type of optically pumped solid polymer dye lasers, which can easily be integrated with polymer based microsystems. The widely used photoresist SU-8 has been functionalized with optical gain, by doping it with Rhodamine 6G laser dye. The laterally emitting lasers can be fabricated on any suitable substrate in a single photo lithographic step on the dye

S. Kragh; S. Balslev; A. Kristensen

44

Single mode pulsed dye laser oscillator  

DOEpatents

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.

Hackel, Richard P. (Livermore, CA)

1992-01-01

45

Resonantly pumped optical pumping injection cavity lasers  

E-print Network

An optical parametric oscillator is tuned to the resonance wavelength of the etalon in an optical pumping injection cavity (OPIC) laser with a type-II "W" active region, thereby minimizing the threshold pump intensity and ...

Santilli, Michael Robert; McAlpine, T. C.; Greene, K. R.; Olafsen, L. J.; Bewley, W. W.; Felix, C. L.; Vurgaftman, I.; Meyer, J. R.; Lee, H.; Martinelli, R. U.

2004-11-01

46

Pumped up Lasers  

NASA Technical Reports Server (NTRS)

Cutting Edge Optronics released the first of potentially three products to result from an SBIR contract with Goddard Space Flight Center. The first commercial result is the WhisperMiniSlab, a diode pump for high performance laser systems. The slab uses a zig-zag path through the laser crystal which eliminates the need for thermal lensing. The result is smaller lasers with better beam quality for use in medical and industrial applications.

2000-01-01

47

Optically pumped molecular bromine laser. Master's thesis  

SciTech Connect

An optically pumped molecular bromine laser was studied to investigate the quenching kinetics state of Br2. This included characterization of the pressure dependence of the laser output power. The approach was to excite molecular bromine in a sealed cell with a Nd:YAG pumped dye laser. Unresolved side fluorescence and amplified stimulated emission (ASE) spectra were recorded. ASE offered the advantage of a simpler optical system with no externally induced wavelength dependencies. Stimulated emission as a signal monitor offered greater resolution than side fluorescence spectra and facilitated spectroscopic assignment. (JS)

Morrison, J.W.

1990-12-01

48

High-Intensity Coherent Vacuum Ultraviolet Source Using Unfocussed Commercial Dye Lasers  

E-print Network

1 High-Intensity Coherent Vacuum Ultraviolet Source Using Unfocussed Commercial Dye Lasers Daniel R Intruments Using two or three commercial pulsed nanosecond dye lasers pumped by a single 30 Hz Nd:YAG laser four-wave mixing of collimated (unfocussed) laser beams in mercury (Hg) vapor. Phase matching

Davis, H. Floyd

49

Fusion reactor pumped laser  

DOEpatents

A nuclear pumped laser capable of producing long pulses of very high power laser radiation is provided. A toroidal fusion reactor provides energetic neutrons which are slowed down by a moderator. The moderated neutrons are converted to energetic particles capable of pumping a lasing medium. The lasing medium is housed in an annular cell surrounding the reactor. The cell includes an annular reflecting mirror at the bottom and an annular output window at the top. A neutron reflector is disposed around the cell to reflect escaping neutrons back into the cell. The laser radiation from the annular window is focused onto a beam compactor which generates a single coherent output laser beam. 10 figs.

Jassby, D.L.

1987-09-04

50

Chemically pumped iodine laser  

Microsoft Academic Search

A chemically pumped iodine-atom laser is described based on electronic energy transfer to atomic iodine from chemically generated O2(1?). The total extracted power (10 W) is approximately 3% of the power contained in the O2(1?) flow.

R. J. Richardson; C. E. Wiswall

1979-01-01

51

Nuclear pumped laser modeling  

NASA Technical Reports Server (NTRS)

A model for an indirectly nuclear pumped laser experiment was developed. The apparatus consists of the usual cylindrical neutron moderator enclosing a gas filled quartz cell. The quartz cell in this case has two concentric compartments; the larger output compartment is filled with He-3 and fluorescent gases which are coupled radiatively to the inner compartment which is filled with a lasing gas for efficient optical pumping. The fluorescent gas in this study was a mixture of Ar, Kr and F2. Perfluoroalkyliodide was chosen as the lasant material of the inner compartment. The degree of photoabsorption in the lasant gas was calculated. The kinetic efficiencies of various gas combinations in the outer fluorescence tube were then evaluated in order to maximize the fluorescence output in the iodine pump band.

Wilson, J. W.; Shapiro, A.

1979-01-01

52

Fluidic fibre dye lasers  

NASA Astrophysics Data System (ADS)

We report the demonstration of compact fluidic fibre lasers based on capillary tubes and photonic crystal fibres, featuring single channel and multiple laterally integrated fluidic lasers respectively. Their preparation was based on capillary action and lasing occurred without the need for external mirrors or lithographically defined microstructures. The fibre lasers were found to be tunable by varying the chromophore density in the liquid core and a functional wavelength selectivity mechanism inherent in both types of lasers provided a long free spectral range that does not correspond to the length of the fibres. The enhanced mode spacing is attributed to a Vernier resonant effect.

Vasdekis, A. E.; Town, G. E.; Turnbull, G. A.; Samuel, I. D. W.

2007-04-01

53

Influence of surfactants on a nonflowing dye laser  

SciTech Connect

The effect of surfactants on the performance of pulsed, laser-pumped, flowing dye lasers has been reported. The use of surfactants in a nonflowing dye cell permits remarkably improved performance in a laser that is much simpler and more compact. The characteristics of such a system are reported here. Solutions of the laser dye rhodamine 590 perchlorate in various solvents were studied. Up to 300% improvement in conversion efficiency was observed for solutions with surfactants. Operation of the laser with the ethylene glycol/sodium dodecyl sulfate solution demonstrated a consistent output of around 8.0 mJ at a repetition rate of 5 Hz. Preliminary results on the laser bandwidth, pulse width, energy stability, and conversion efficiency will be presented.

Moran, M.B.; Marrs, C.D.

1988-05-15

54

Trans-spectral organic dye laser photocoagulation.  

PubMed

Clinical research utilizing the yellow, orange, and red wavelengths of the dye laser (Rhodamine 6G and MD-631) appears to have considerable promise and may demonstrate that the liquid organic dye laser is the laser of choice for photocoagulation of many types of ocular defects. The effectiveness of the dye laser as a photocoagulation source is due to the trans-spectral availability of relatively high output power wavelengths. Therefore, a target tissue can be selectively coagulated with minimal laser energy transmitted through the refractive media and minimal damage to nearby normal tissues. The dye laser, as a photocoagulation system, should prove valuable in the therapy of many ocular diseases. PMID:2421474

L'Esperance, F A

1985-01-01

55

Solar Pumped Laser Microthruster  

NASA Astrophysics Data System (ADS)

The development of microsatellites requires the development of engines to modify their orbit. It is natural to use solar energy to drive such engines. For an unlimited energy source the optimal thruster must use a minimal amount of expendable material to minimize launch costs. This requires the ejected material to have the maximal velocity and, hence, the ejected atoms must be as light as possible and be ejected by as high an energy density source as possible. Such a propulsion can be induced by pulses from an ultra-short laser. The ultra-short laser provides the high-energy concentration and high-ejected velocity. We suggest a microthruster system comprised of an inflatable solar concentrator, a solar panel, and a diode-pumped fiber laser. We will describe the system design and give weight estimates.

Rubenchik, A. M.; Beach, R.; Dawson, J.; Siders, C. W.

2010-10-01

56

Direct solar-pumped lasers  

NASA Technical Reports Server (NTRS)

The feasibility of direct solar pumping of an iodine photodissociation laser at lambda = 1.315 microns was investigated. Threshold inversion density and effect of elevated temperature (up to 670 K) on the laser output were measured. These results and the concentration of solar radiation required for the solar pumped iodine laser are discussed.

Lee, J. H.; Shiu, Y. J.; Weaver, W. R.

1980-01-01

57

Diode pumped solid-state laser oscillators for spectroscopic applications  

NASA Technical Reports Server (NTRS)

The rapid improvement in diode laser pump sources has led to the recent progress in diode laser pumped solid state lasers. To date, electrical efficiencies of greater than 10 percent were demonstrated. As diode laser costs decrease with increased production volume, diode laser and diode laser array pumped solid state lasers will replace the traditional flashlamp pumped Nd:YAG laser sources. The use of laser diode array pumping of slab geometry lasers will allow efficient, high peak and average power solid state laser sources to be developed. Perhaps the greatest impact of diode laser pumped solid state lasers will be in spectroscopic applications of miniature, monolithic devices. Single-stripe diode-pumped operation of a continuous-wave 946 nm Nd:YAG laser with less than 10 m/w threshold was demonstrated. A slope efficiency of 16 percent near threshold was shown with a projected slope efficiency well above a threshold of 34 percent based on results under Rhodamine 6G dye-laser pumping. Nonlinear crystals for second-harmonic generation of this source were evaluated. The KNbO3 and periodically poled LiNbO3 appear to be the most promising.

Byer, R. L.; Basu, S.; Fan, T. Y.; Kozlovsky, W. J.; Nabors, C. D.; Nilsson, A.; Huber, G.

1987-01-01

58

Tunable narrow-band UV laser system pumped by a copper vapour laser  

SciTech Connect

A narrow-band laser system is designed, which produces 10-ns pulses of tunable UV radiation with an average power of 3 W, pulse repetition rate of 12 kHz, and linewidth smaller than 45 MHz. The system uses a cw dye laser as a master oscillator. Its radiation is amplified by a three-stage dye system whose output signal is frequency doubled in a BBO crystal. The system is pumped by a copper vapour laser. (lasers)

Bokhan, P A; Zakrevskii, D E; Kochubei, S A; Stepanov, A Yu [Institute of Semiconductor Physics, Siberian Branch of the Russian Academy of Sciences, Novosibirsk (Russian Federation); Fateev, N V [Institute of Laser Physics, Siberian Branch, Russian Academy of Sciences, Novosibirsk (Russian Federation)

2001-02-28

59

Optically pumped hydrogen fluoride laser  

Microsoft Academic Search

We present results from a study of an optically pumped hydrogen fluoride laser. Rotation–vibration transitions within the (2,0) band near 1.3 ?m are pumped, and both amplified spontaneous emission (ASE) and laser oscillation are observed on (2,1) band transitions near 2.7 ?m. Longitudinal and transverse pumping schemes are discussed. We also have pumped the (3,0) band and observed ASE on

William J. Kessler; Steven J. Davis; Harold C. Miller; Gordon D. Hager

1998-01-01

60

Optically pumped hydrogen fluoride laser  

Microsoft Academic Search

We present results from a study of an optically pumped hydrogen fluoride laser. Rotation-vibration transitions within the (2,0) band near 1.3 mum are pumped, and both amplified spontaneous emission (ASE) and laser oscillation are observed on (2,1) band transitions near 2.7 mum. Longitudinal and transverse pumping schemes are discussed. We also have pumped the (3,0) band and observed ASE on

William J. Kessler; Steven J. Davis; Harold C. Miller; Gordon D. Hager

1998-01-01

61

Nd Laser Pumped by Laser Diodes.  

National Technical Information Service (NTIS)

Performance data for laser diode pumped cw Nd:BEL and Nd :YAG lasers are presented. Two phased laser diode arrays are used as the pump source, each emitting 500 mW. The heat sink for the arrays is temperature controlled to allow for wavelength tunability....

R. Scheps

1989-01-01

62

Direct solar-pumped iodine laser amplifier. Semiannual Progress Report, 1 April30 September 1985  

Microsoft Academic Search

During this period the parametric studies of the iodine laser oscillator pumped by a Vortek simulator was carried out before the amplifier studies. The amplifier studies are postponed to the extended period following completion of the parametric studies. In addition, the kinetic modeling of a solar pumped iodine laser amplifier, and the experimental work for a solar pumped dye laser

Han

1985-01-01

63

Dye laser tuning with pellicles.  

NASA Technical Reports Server (NTRS)

Thin nitrocellulose membranes (pellicles) are shown to exhibit properties which make them suitable for intracavity tuning elements in high-energy pulsed dye lasers. Uncoated pellicles of 2-micron and 8-micron thickness with surface figures of lambda/1 are shown to closely approximate the properties of low-finesse etalons with wide free spectral ranges. Pellicles of 8-micron thickness, coated on both surfaces with 50% reflectivity multilayer dielectrics, are shown to be effective as spectral narrowing elements with peak transmission greater than 80% and resultant laser linewidths of 0.57 nm full width at half-maximum.

Mumola, P. B.

1973-01-01

64

Direct solar-pumped iodine laser amplifier. Semiannual progress report, 1 March-31 August 1986  

SciTech Connect

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

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

1986-11-01

65

Amplified spontaneous emission in narrow-band pulsed dye laser oscillators--theory and experiment  

SciTech Connect

We have investigated the effect of amplified spontaneous emission (ASE) on the spectral and temporal characteristics of narrowband pulsed dye laser oscillators. The space and time dependent rate equations for the molecular populations and photon fluxes have been solved numberically to study the dependence of ASE on various laser parameters and the effects of ASE on the spectral and temporal profile of the dye laser output. To account for the diffraction losses present in a real dye laser oscillator, appropriate feedback factors for the laser and ASE photon fluxes were introduced into the boundary conditions for the oscillator. These theoretical results have been substantiated by experimental measurements of ASE in a narrow-band pulsed dye laser oscillator. We show that a considerable reduction of ASE in a grazing incidence grating dye laser oscillator can be obtained by appropriately shaping the pump pulse. Oscillations observed in the temporal output of pulsed dye lasers are also discussed.

Nair, L.G.; Dasgupta, K.

1985-11-01

66

Single-mode pulsed tunable dye laser  

NASA Astrophysics Data System (ADS)

The design and performance of a tunable single-mode optically pumped grazing-incidence pulsed dye laser are reported. The device is a modified version of the laser described by Littman and Metcalf (1978) and Liu and Littman (1981) and comprises a 2-mm-path-length dye cell, a 1.27 x 2.5-cm 2400 line/mm diffraction grating, two 2.5-cm-diameter lambda/20 dielectric mirrors, a 4-in.-diameter rotation stage, a 100-nm-resolution differential micrometer, three 2.5-cm-square mounts, a 2.5-cm-diameter 750-mm lens, and a translation stage. Performance parameters include time-averaged linewidth less than 150 MHz, near-TEM(00)-mode operation, tuning range greater than 15/cm without mode hopping, background light less than 0.01 percent, and efficiency 3 percent. A drawing of the apparatus, Fizeau interferograms of the scanning pattern, and a photograph showing the spatial mode of the laser are provided.

Littman, M. G.

1984-12-01

67

Capillary driven tunable optofluidic DFB dye lasers  

NASA Astrophysics Data System (ADS)

We present the design and operation of low-threshold and widely tunable polymer-based nanofluidic distributed feedback (DFB) dye lasers. The devices rely on light-confinement in a nanostructured polymer film embedded between two substrates. An array of nanofluidic channels forms a Bragg grating DFB laser resonator relying on the third order Bragg reflection. The lasers are fabricated by Combined Electron beam and UV Lithography (CEUL) in a thin film of SU-8 resist and polymer mediated wafer bonding. The devices are operated without the need for external fluidic handling apparatus. Capillary action drives the liquid dye infiltration of the nanofluidic DFB lasers and accounts for dye replenishment. The low Bragg reflection order yields: (i) low out-of-plane scattering losses, (ii) low coupling losses for the light when traversing the dye-filled nanofluidic channels due to the sub-wavelength dimensions of the resonator segments, and (iii) a large free spectral range (FSR). Points (i)+(ii) enable a low threshold for lasing, point (iii) facilitates wavelength tuning over the full gain spectrum of the chosen laser dye without mode-hopping. By combining different grating periods and dye solution refractive indices, we demonstrate a tuning range of 45 nm using a single laser dye and obtain laser threshold fluences down to ~ 7 ?J/mm2. The lasers are straightforward to integrate on lab-on-a-chip microsystems, e.g. for novel sensor concepts, where coherent light in the visible range is desired.

Gersborg-Hansen, Morten; Kristensen, Anders

2007-09-01

68

An electrically pumped germanium laser  

E-print Network

Electrically pumped lasing from Germanium-on-Silicon pnn heterojunction diode structures is demonstrated. Room temperature multimode laser with 1mW output power is measured. Phosphorous doping in Germanium at a concentration ...

Cai, Yan

69

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

PubMed

Flashlamp-pumped pulsed dye laser is the preferred treatment for port-wine stain. Vascular hemoglobin and epidermal melanin are competing sites for dye laser absorption and damage. The case presented illustrates the potential hazard of ignition induced by dye laser treatment on the face of a patient receiving inhalation anesthesia. A 6-year-old girl with almost black hair was treated for a port-wine stain covering most of the right half of her face. She was treated with dye laser under general anesthesia administered by mask. A laser pulse close to the upper part of the eyebrow induced a blaze and the eyebrow was instantly destroyed by the fire. Regrowth of the eyebrow was complete after a few months. Hair specimens of various colors were exposed experimentally to dye laser irradiation in room and oxygen-saturated atmospheres. Risk factors of ignition are high laser dosage, a high oxygen level, repeated pulses and dark colored hair. PMID:11357290

Molin, L; Hallgren, S

1999-04-01

70

Distributed feedback dye-doped sol-gel silica lasers  

NASA Astrophysics Data System (ADS)

Solid state dye lasers with narrow linewidth and short pulse duration have attracted increasing attention because of their potential applications. Distributed feedback (DFB) laser is an effective compact coherent light source capable of tunable output with narrow linewidth. In this dissertation, lasing characteristics of dye doped sol-gel silica distributed feedback lasers have been investigated. The optical properties of sol-gel silica deduced from measurements of DFB laser output have also been studied. High optical homogeneity sol-gel silica slabs doped with desired concentration of Rhodamine 6G (MG), Coumarin 460 (C460), or Exalite 377E (E377) dye have been fabricated. Spatial periodic gain modulation in the dye doped sol-gel silica slab was created by crossing the diffracted pump beams from a holographic grating (1800 lines/mm) used as a beam splitter. Tunable laser emission in the yellow, the blue, and in the near ultraviolet region has been generated from the distributed feedback geometry using sol-gel silica slabs doped with R6G, C460 or E377 dye respectively. Wavelength tuning range of approximately 20 nm around the emission centers (562 nm, 480 nm, 376 nm) has been realized by varying the pump beams intersection angle. The laser linewidth was of the order of 60~80 pm when pump energy was several times over the threshold. Laser pulse trains with sub-nanosecond spikes were induced. A slope efficiency of approximately 4.5% has been obtained. The time behavior of distributed feedback R6G doped sol- gel silica laser has been studied using a N2 laser as the pump source. Sub-nanosecond pulse duration has been obtained. The pulse number in the output pulse train is sensitive to the pump energy. Experimental results of the time behavior are in good agreement with theoretical calculations. The lasing performance of tunable distributed feedback dye-doped sol-gel silica laser operating at different Bragg scattering order (M = 1, 2, 3) has also been studied. Distributed feedback laser operating at higher Bragg scattering order was observed at higher pump energy threshold and with lower energy conversion efficiency. The energy conversion efficiency of 0.7% (for M = 3) and 11% (for M = 2) has been achieved. Based on the Bragg scattering condition and the temperature dependence of the refractive index (?) of the gain medium, temperature tuning of the laser output was realized in experiment from the distributed feedback R6G doped sol-gel silica/PMMA lasers. Wavelength tuning from 573 nm to 556 mm has been demonstrated by varying the temperature from 21°C to 58°C. The laser linewidth was kept below 0.5 mm within the whole tuning range. The thermal coefficient of the emission wavelength has been measured. Finally the thermal coefficient of refractive index of sol-gel silica has been derived from these experimental data. Discontinuity in d?/dT curve attributable to phase transition has been observed in dye doped sol-gel silica slab and PMMA bulk. Temperature tuning performance of DFB laser using high temperature treated sol-gel silica as the gain medium has also been investigated.

Zhu, Xiaolei

71

Study of excitation transfer in flowing helium afterglow pumped with a tuneable dye laser. 2: Measurement of the rate coefficient for the rotational relaxation of He2(3p (3 Pi g))  

NASA Technical Reports Server (NTRS)

The rotational relaxation of the He2(3p(3pi g)) state is examined by optically pumping a flowing helium afterglow with a tuneable dye laser. The population of the J = 8 rotational state is enhanced by optically saturating the R sub 7 component of the transition connecting this state with the metastable He2(2s (3 Sigma u +)) molecular state. From the lifetime and yield of the Q sub 7 component, the rate coefficient for the rotational relaxation via the forbidden delta J = 1 channel is determined to be of the order of 2 x 10 to the minus 11th power cm3/sec. It is found that this represents about half of the total rate of rotational relaxation in this state.

Collins, C. B.; Johnson, B. W.

1972-01-01

72

Optically pumped molecular beam lasers  

SciTech Connect

Investigations on Na/sub 2/ and I/sub 2/ dimer lasers using a supersonic molecular beam as laser active material have been performed. In the case of Na/sub 2/ a threshold pump power of only 17 ..mu..W has been obtained.

Wellegehausen, B.; Gaubatz, U.; Bergmann, K.

1986-08-15

73

Optically pumped iodine monofluoride laser  

Microsoft Academic Search

In accordance with the present invention, there is provided a short wavelength chemical laser device which utilizes iodine monofluoride as a lasing medium. The device is an optically pumped iodine monofluoride laser in which the ground state iodine monofluoride is produced by reacting iodine and fluorine to form a flame within which the monofluoride is produced. The monofluoride is then

S. J. Davis; L. Hanko

1984-01-01

74

Direct solar-pumped iodine laser amplifier. Semiannual progress report, 1 October 1985-30 March 1986  

Microsoft Academic Search

During this period the parametric studies of the iodine laser oscillator pumped by a Vortek simulator were carried out before amplifier studies. The amplifier studies are postponed to the extended period after completing the parametric studies. In addition, the kinetic modeling of a solar-pumped iodine laser amplifier, and the experimental work for a solar pumped dye laser amplifier are in

Han

1986-01-01

75

Chemically pumped iodine laser  

Microsoft Academic Search

McDermott et al. (1978) have developed a practical O2(1 Delta) generator based on bubbling Cl2 in alkaline H2O2. In the work described in the present paper, it proved possible to convert a transverse-flow mixing chemical laser, originally designed as a CO chemical laser, to a chemical iodine-atom laser by installing a version of the McDermott generator on the laser. The

R. J. Richardson; C. E. Wiswall

1979-01-01

76

Selective Emitter Pumped Rare Earth Laser  

NASA Technical Reports Server (NTRS)

A selective emitter pumped rare earth laser provides an additional type of laser for use in many laser applications. Rare earth doped lasers exist which are pumped with flashtubes or laser diodes. The invention uses a rare earth emitter to transform thermal energy input to a spectral band matching the absorption band of a rare earth in the laser in order to produce lasing.

Chubb, Donald L. (Inventor); Patton, Martin O. (Inventor)

2001-01-01

77

New laser materials for laser diode pumping  

NASA Technical Reports Server (NTRS)

The potential advantages of laser diode pumped solid state lasers are many with high overall efficiency being the most important. In order to realize these advantages, the solid state laser material needs to be optimized for diode laser pumping and for the particular application. In the case of the Nd laser, materials with a longer upper level radiative lifetime are desirable. This is because the laser diode is fundamentally a cw source, and to obtain high energy storage, a long integration time is necessary. Fluoride crystals are investigated as host materials for the Nd laser and also for IR laser transitions in other rare earths, such as the 2 micron Ho laser and the 3 micron Er laser. The approach is to investigate both known crystals, such as BaY2F8, as well as new crystals such as NaYF8. Emphasis is on the growth and spectroscopy of BaY2F8. These two efforts are parallel efforts. The growth effort is aimed at establishing conditions for obtaining large, high quality boules for laser samples. This requires numerous experimental growth runs; however, from these runs, samples suitable for spectroscopy become available.

Jenssen, H. P.

1990-01-01

78

Direct solar-pumped iodine laser amplifier. Semiannual Progress Report, 1 April-30 September 1985  

SciTech Connect

During this period the parametric studies of the iodine laser oscillator pumped by a Vortek simulator was carried out before the amplifier studies. The amplifier studies are postponed to the extended period following completion of the parametric studies. In addition, the kinetic modeling of a solar pumped iodine laser amplifier, and the experimental work for a solar pumped dye laser amplifier are in progress. This report contains three parts: (1) the radiation characteristics of solar simulator and the parametric characteristics of photodissociation iodine laser continuously pumped by a Vortek solar simulator; (2) kinetic modeling of a solar pumped iodine laser amplifier; and (3) the study of the dye laser amplifier pumped by a Tamarack solar simulator.

Han, K.S.

1985-09-01

79

Electron beam pumped semiconductor laser  

NASA Technical Reports Server (NTRS)

Electron-beam-pumped semiconductor ultra-violet optical sources (ESUVOSs) are disclosed that use ballistic electron pumped wide bandgap semiconductor materials. The sources may produce incoherent radiation and take the form of electron-beam-pumped light emitting triodes (ELETs). The sources may produce coherent radiation and take the form of electron-beam-pumped laser triodes (ELTs). The ELTs may take the form of electron-beam-pumped vertical cavity surface emitting lasers (EVCSEL) or edge emitting electron-beam-pumped lasers (EEELs). The semiconductor medium may take the form of an aluminum gallium nitride alloy that has a mole fraction of aluminum selected to give a desired emission wavelength, diamond, or diamond-like carbon (DLC). The sources may be produced from discrete components that are assembled after their individual formation or they may be produced using batch MEMS-type or semiconductor-type processing techniques to build them up in a whole or partial monolithic manner, or combination thereof.

Hug, William F. (Inventor); Reid, Ray D. (Inventor)

2009-01-01

80

Gas-phase optically pumped infrared lasers  

Microsoft Academic Search

This experimental research program is designed to assess the possibility of using gas-phase optically pumped lasers (OPL) as efficient, frequency-agile mid-infrared sources. The eventual goal will be to incorporate efficient diode lasers into the pumping step, either by direct frequency stabilized diode pumping or by pumping with diode-pumped solid state lasers. In this paper, we discuss experiments on a optically

Harold C. Miller; Dan T. Radzykewycz; Gordon D. Hager; William J. Kessler; Steven J. Davis

1993-01-01

81

Approximate analytic solutions for the optical pumping of fluorescent dyes  

NASA Technical Reports Server (NTRS)

A general technique for solving a system of rate equations describing the interaction of an electromagnetic field and a molecular system is presented. The method is used to obtain approximate time-dependent solutions for the upper-level population of fluorescent dyes in the presence of a pump field.

Lawandy, N. M.

1978-01-01

82

Confinement of pyridinium hemicyanine dye within an anionic metal-organic framework for two-photon-pumped lasing  

NASA Astrophysics Data System (ADS)

Two-photon-pumped dye lasers are very important because of their applications in wavelength up-conversion, optical data storage, biological imaging and photodynamic therapy. Such lasers are very difficult to realize in the solid state because of the aggregation-caused quenching. Here we demonstrate a new two-photon-pumped micro-laser by encapsulating the cationic pyridinium hemicyanine dye into an anionic metal-organic framework (MOF). The resultant MOF?dye composite exhibits significant two-photon fluorescence because of the large absorption cross-section and the encapsulation-enhanced luminescent efficiency of the dye. Furthermore, the well-faceted MOF crystal serves as a natural Fabry-Perot resonance cavity, leading to lasing around 640?nm when pumped with a 1064-nm pulse laser. This strategy not only combines the crystalline benefit of MOFs and luminescent behaviour of organic dyes but also creates a new synergistic two-photon-pumped lasing functionality, opening a new avenue for the future creation of solid-state photonic materials and devices.

Yu, Jiancan; Cui, Yuanjing; Xu, Hui; Yang, Yu; Wang, Zhiyu; Chen, Banglin; Qian, Guodong

2013-10-01

83

Confinement of pyridinium hemicyanine dye within an anionic metal-organic framework for two-photon-pumped lasing.  

PubMed

Two-photon-pumped dye lasers are very important because of their applications in wavelength up-conversion, optical data storage, biological imaging and photodynamic therapy. Such lasers are very difficult to realize in the solid state because of the aggregation-caused quenching. Here we demonstrate a new two-photon-pumped micro-laser by encapsulating the cationic pyridinium hemicyanine dye into an anionic metal-organic framework (MOF). The resultant MOF [symbol: see text] dye composite exhibits significant two-photon fluorescence because of the large absorption cross-section and the encapsulation-enhanced luminescent efficiency of the dye. Furthermore, the well-faceted MOF crystal serves as a natural Fabry-Perot resonance cavity, leading to lasing around 640 nm when pumped with a 1064-nm pulse laser. This strategy not only combines the crystalline benefit of MOFs and luminescent behaviour of organic dyes but also creates a new synergistic two-photon-pumped lasing functionality, opening a new avenue for the future creation of solid-state photonic materials and devices. PMID:24173352

Yu, Jiancan; Cui, Yuanjing; Xu, Hui; Yang, Yu; Wang, Zhiyu; Chen, Banglin; Qian, Guodong

2013-01-01

84

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

DOEpatents

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.

Davin, James (Gilroy, CA)

1992-01-01

85

Fusion pumped laser  

DOEpatents

Apparatus is provided for generating energy in the form of laser radiation. A tokamak fusion reactor is provided for generating a long, or continuous, pulse of high-energy neutrons. The tokamak design provides a temperature and a magnetic field which is effective to generate a neutron flux of at least 10.sup.15 neutrons/cm.sup.2.s. A conversion medium receives neutrons from the tokamak and converts the high-energy neutrons to an energy source with an intensity and an energy effective to excite a preselected lasing medium. The energy source typically comprises fission fragments, alpha particles, and radiation from a fission event. A lasing medium is provided which is responsive to the energy source to generate a population inversion which is effective to support laser oscillations for generating output radiation.

Pappas, Daniel S. (Los Alamos, NM)

1989-01-01

86

Fusion pumped laser  

DOEpatents

The apparatus of this invention may comprise a system for generating laser radiation from a high-energy neutron source. The neutron source is a tokamak fusion reactor generating a long pulse of high-energy neutrons and having a temperature and magnetic field effective to generate a neutron flux of at least 10/sup 15/ neutrons/cm/sup 2//center dot/s. Conversion means are provided adjacent the fusion reactor at a location operable for converting the high-energy neutrons to an energy source with an intensity and energy effective to excite a preselected lasing medium. A lasing medium is spaced about and responsive to the energy source to generate a population inversion effective to support laser oscillations for generating output radiation. 2 figs., 2 tabs.

Pappas, D.S.

1987-07-31

87

Flashlamp pumped laser technology; Proceedings of the Meeting, Los Angeles, CA, Jan. 21, 22, 1986  

NASA Astrophysics Data System (ADS)

Consideration is given to flashlamps and arc lamps, the power conditioning for flashlamps and arc lamps, solid-state laser pump cavity designs, the characterization of high power flashlamps and their application to Nd, and the optimized flashlamp pumping of disk amplifiers. Topics discussed include high energy and high average power flashlamp excited dye lasers, the flashlamp pumping of slab lasers, flashlamp technology used in military laser systems, and the design of industrial CW-pumped Nd:YAG lasers. Papers are presented on the effects of design and operational constraints on flashlamps for industrial pulsed lasers, scientific applications for flashlamp pumped Nd:YAG lasers, advances in pump source technology, and lanthanide series and transition metal solid-state lasers.

Schuda, Felix

1986-01-01

88

Optofluidic third order distributed feedback dye laser  

NASA Astrophysics Data System (ADS)

This letter describes the design and operation of a polymer-based third order distributed feedback (DFB) microfluidic dye laser. The device relies on light confinement in a nanostructured polymer film where an array of nanofluidic channels is filled by capillary action with a liquid dye solution which has a refractive index lower than that of the polymer. In combination with a third order DFB grating, formed by the array of nanofluidic channels, this yields a low threshold for lasing. The laser is straightforward to integrate on lab-on-a-chip microsystems where coherent, tunable light in the visible range is desired.

Gersborg-Hansen, Morten; Kristensen, Anders

2006-09-01

89

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

NASA Technical Reports Server (NTRS)

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

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

1986-01-01

90

An efficient, diode-pumped, ion-implanted Nd: GGG planar waveguide laser  

NASA Astrophysics Data System (ADS)

We report the first laser operation of an ion-implanted Nd: GGG planar waveguide laser at 1.062 ?m. Diode array and dye laser pumping is described with threshold absorbed powers as low as 8 mW. Slope efficiencies of 30% with respect to absorbed power have been observed with output powers of up to 40 mW.

Field, S. J.; Hanna, D. C.; Large, A. C.; Shepherd, D. P.; Tropper, A. C.; Chandler, P. J.; Townsend, P. D.; Zhang, L.

1991-11-01

91

Volumetric direct nuclear pumped laser  

NASA Technical Reports Server (NTRS)

A volumetric direct nuclear pumped laser was developed in which the gas is a mixture of He-3 and a minority gas from the group of argon, krypton, xenon, chlorine and fluorine. The mixture of He-3 and the minority gas produces lasing with a minority gas concentration of from 0.01 to 10 percent argon, 1 percent krypton, 0.01 to 5 percent xenon and small concentrations of chlorine or fluorine.

Jalufka, N. W.; Hohl, F.; Deyoung, R. J.; Williams, M. D. (inventors)

1978-01-01

92

The effect of incident angle of pumping light on Cholesteric Liquid Crystal tunable laser wavelength  

E-print Network

One notable feature of dye doped cholesteric liquid crystal is the variation of pitch and refractive index as the incidence angle of the pumping light shifts. Based on this feature, this paper studies the effects of pumping light's incidence angle on emission properties of the dye doped cholesteric liquid crystal tunable laser. First, we investigated the relationship among the concentration of chiral reagent, the incidence angle of the pumping light, and the pitch of liquid-crystal display (LCD); then we made a tunable-wavelength laser and pumped the prepared sample with 532nm laser outputted from the Nd: YAG multi-frequency pulse laser. As the incident angle of the pumping light shifts between 20 {\\deg} ~ 90 {\\deg}, the tuning range of the wavelength emitted by the laser reaches 10.73nm, ranging between 647.38nm and 658.11nm.

Yin, Xiangbao

2014-01-01

93

Intracavity dye-laser photothermal deflection spectroscopy  

SciTech Connect

An intracavity, cw, dye-laser photothermal deflection (PTD) technique has been developed for gas-phase vibrational overtone spectroscopy. This new technique has a similar S/N ratio and significantly lower window noise than the intracavity photoacoustic technique under identical conditions.

Reddy, K.V.

1983-04-01

94

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

NASA Technical Reports Server (NTRS)

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.

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

1987-01-01

95

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

DOEpatents

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.

Davin, James (Gilroy, CA)

1992-01-01

96

Direct solar-pumped iodine laser amplifier  

NASA Astrophysics Data System (ADS)

The improvement on the collection system of the Tarmarack Solar Simulator beam was attemped. The basic study of evaluating the solid state laser materials for the solar pumping and also the work to construct a kinetic model algorithm for the flashlamp pumped iodine lasers were carried out. It was observed that the collector cone worked better than the lens assembly in order to collect the solar simulator beam and to focus it down to a strong power density. The study on the various laser materials and their lasing characteristics shows that the neodymium and chromium co-doped gadolinium scandium gallium garnet (Nr:Cr:GSGG) may be a strong candidate for the high power solar pumped solid state laser crystal. On the other hand the improved kinetic modeling for the flashlamp pumped iodine laser provides a good agreement between the theoretical model and the experimental data on the laser power output, and predicts the output parameters of a solar pumped iodine laser.

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

1987-02-01

97

Direct solar-pumped iodine laser amplifier  

NASA Technical Reports Server (NTRS)

The improvement on the collection system of the Tarmarack Solar Simulator beam was attemped. The basic study of evaluating the solid state laser materials for the solar pumping and also the work to construct a kinetic model algorithm for the flashlamp pumped iodine lasers were carried out. It was observed that the collector cone worked better than the lens assembly in order to collect the solar simulator beam and to focus it down to a strong power density. The study on the various laser materials and their lasing characteristics shows that the neodymium and chromium co-doped gadolinium scandium gallium garnet (Nr:Cr:GSGG) may be a strong candidate for the high power solar pumped solid state laser crystal. On the other hand the improved kinetic modeling for the flashlamp pumped iodine laser provides a good agreement between the theoretical model and the experimental data on the laser power output, and predicts the output parameters of a solar pumped iodine laser.

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

1987-01-01

98

Direct solar-pumped iodine laser amplifier  

Microsoft Academic Search

A XeCl laser pumped iodine laser oscillator was developed which will be incorporated into the Master Oscillator Power Amplifier (MOPA) system. The developed XeCl laser produces output energy of about 60 mJ per pulse. The pulse duration was about 10 nsec. The kinetic model for the solar-pumped laser was refined and the algorithm for the calculation of a set of

Kwang S. Han; In Heon Hwang; Khong Hon Kim; Larry V. Stock

1988-01-01

99

Direct solar-pumped iodine laser amplifier. Semiannual progress report, 1 October 1985-30 March 1986  

SciTech Connect

During this period the parametric studies of the iodine laser oscillator pumped by a Vortek simulator were carried out before amplifier studies. The amplifier studies are postponed to the extended period after completing the parametric studies. In addition, the kinetic modeling of a solar-pumped iodine laser amplifier, and the experimental work for a solar pumped dye laser amplifier are in progress. This report contains three parts: (1) a 10 W CW iodine laser pumped by a Vortek solar simulator; (2) kinetic modeling to predict the time to lasing threshold, lasing time, and energy output of solar-pumped iodine laser; and (3) the study of the dye laser amplifier pumped by a Tamarack solar simulator.

Han, K.S.

1986-03-01

100

Direct solar-pumped iodine laser amplifier  

Microsoft Academic Search

This semiannual progress report covers the period from April 1, 1985 to Sept. 30, 1985 under NASA grant NAS1-441 entitled direct solar pumped iodine laser amplifier. During this period the parametric studies of the iodine laser oscillator pumped by a Vortek simulator was carried out before the amplifier studies. The amplifier studies are postponed to the extended period following completion

K. S. Han

1985-01-01

101

Direct solar-pumped iodine laser amplifier  

Microsoft Academic Search

The improvement on the collection system of the Tarmarack Solar Simulator beam was attemped. The basic study of evaluating the solid state laser materials for the solar pumping and also the work to construct a kinetic model algorithm for the flashlamp pumped iodine lasers were carried out. It was observed that the collector cone worked better than the lens assembly

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

1987-01-01

102

Nd:BEL Laser Pumped by Laser Diodes.  

National Technical Information Service (NTIS)

Performance data for a laser diode pumped cw Nd:BEL laser is presented . Two phased laser diode arrays are used as the pump source, each emitting 500 mW. The heat sink for the arrays is temperature controlled to allow for wavelength tunability. A Nd:YAG r...

D. F. Heller, E. J. Schimitschek, J. Myers, R. Scheps

1988-01-01

103

Dye laser amplifier including a specifically designed diffuser assembly  

DOEpatents

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.

Davin, James (Gilroy, CA); Johnston, James P. (Stanford, CA)

1992-01-01

104

Direct solar-pumped iodine laser amplifier  

NASA Technical Reports Server (NTRS)

The optimum conditions of a solar pumped iodine laser are found in this research for the case of a continuous wave operation and a pulsed operation. The optimum product of the pressure(p) inside the laser tube and the tube diameter(d) was pd=40 approx. 50 torr-cm on the contrary to the case of a high intensity flashlamp pumped iodine laser where the optimum value of the product is known to be pd=150 torr-cm. The pressure-diameter product is less than 1/3 of that of the high power iodine laser. During the research period, various laser materials were also studied for solar pumping. Among the laser materials, Nd:YAG is found to have the lowest laser threshold pumping intensity of about 200 solar constant. The Rhodamine 6G was also tested as the solar pumped laser material. The threshold pumping power was measured to be about 20,000 solar constant. The amplification experiment for a continuously pumped iodine laser amplifier was performed using Vortek solar simulator and the amplification factors were measured for single pass amplification and triple pass amplification of the 15 cm long amplifier tube. The amplification of 5 was obtained for the triple pass amplification.

Han, Kwang S.; Hwang, In Heon

1990-01-01

105

Diode laser--pumped solid-state lasers.  

PubMed

Diode laser-pumped solid-state lasers are efficient, compact, all solid-state sources of coherent optical radiation. Major advances in solid-state laser technology have historically been preceded by advances in pumping technology. The helical flash lamps used to pump early ruby lasers were superseded by the linear flash lamp and arc lamp now used to pump neodymium-doped yttrium-aluminum-garnet lasers. The latest advance in pumping technology is the diode laser. Diode laser-pumped neodymium lasers have operated at greater than 10 percent electrical to optical efficiency in a single spatial mode and with linewidths of less than 10 kilohertz. The high spectral power brightness of these lasers has allowed frequency extension by harmonic generation in nonlinear crystals, which has led to green and blue sources of coherent radiation. Diode laser pumping has also been used with ions other than neodymium to produce wavelengths from 946 to 2010 nanometers. In addition, Q-switched operation with kilowatt peak powers and mode-locked operation with 10-picosecond pulse widths have been demonstrated. Progress in diode lasers and diode laser arrays promises all solid-state lasers in which the flash lamp is replaced by diode lasers for average power levels in excess of tens of watts and at a price that is competitive with flash lamp-pumped laser systems. Power levels exceeding 1 kilowatt appear possible within the next 5 years. Potential applications of diode laser-pumped solid-state lasers include coherent radar, global sensing from satellites, medical uses, micromachining, and miniature visible sources for digital optical storage. PMID:17832940

Byer, R L

1988-02-12

106

Direct solar-pumped iodine laser amplifier  

Microsoft Academic Search

The optimum conditions of a solar pumped iodine laser are found in this research for the case of a continuous wave operation and a pulsed operation. The optimum product of the pressure(p) inside the laser tube and the tube diameter(d) was pd=40 approx. 50 torr-cm on the contrary to the case of a high intensity flashlamp pumped iodine laser where

Kwang S. Han; In Heon Hwang

1990-01-01

107

Tuning of a narrow linewidth pulsed dye laser with a Fabry-Perot and diffraction grating over a large wavelength range  

SciTech Connect

It is shown that the motion of a diffraction grating and an air-spaced Fabry-Perot interferometer in a Haensch-type dye laser can be synchronized. A nitrogen-pumped dye laser built according to this principle was capable of resolving the iodine spectra over more than 30 nm. Result and error sources are discussed in detail.

Olcay, M.R.; Pasqual, J.A.; Lisboa, J.A.; Francke, R.E.

1985-10-01

108

CCMR: Analysis of Surface Dyes: Preparation for Laser Spectroscopy  

NSDL National Science Digital Library

Preliminary work for laser spectroscopy with surface-adsorbed dyes is presented. Prussian blue dye is characterized and future sum-frequency generation experiments are described. Ultrafast surface-specific laser spectroscopy is utilized as an effective way of directly studying electron transfer between dye and semiconductor in dye-sensitized solar cells. Previous studies and theories have not allowed these electron transfer mechanisms to be fully understood. Future work will utilize infrared analysis to observe vibrational modes in dye and form a picture of electron transfer.

Souva, Matthew

2010-08-15

109

Direct solar-pumped iodine laser amplifier  

NASA Technical Reports Server (NTRS)

This semiannual progress report covers the period from March 1, 1987 to September 30, 1987 under NASA grant NAG1-441 entitled 'Direct solar-pumped iodine laser amplifier'. During this period Nd:YAG and Nd:Cr:GSGG crystals have been tested for the solar-simulator pumped cw laser, and loss mechanisms of the laser output power in a flashlamp-pumped iodine laser also have been identified theoretically. It was observed that the threshold pump-beam intensities for both Nd:YAG and Nd:Cr:GSGG crystals were about 1000 solar constants, and the cw laser operation of the Nd:Cr:GSGG crystal was more difficult than that of the Nd:YAG crystal under the solar-simulator pumping. The possibility of the Nd:Cr:GSGG laser operation with a fast continuously chopped pumping was also observed. In addition, good agreement between the theoretical calculations and the experimental data on the loss mechanisms of a flashlamp-pumped iodine laser at various fill pressures and various lasants was achieved.

Han, Kwang S.

1987-01-01

110

Diode laser-pumped solid-state lasers  

NASA Technical Reports Server (NTRS)

Recently, interest in diode laser-pumped solid-state lasers has increased due to their advantages over flashlamp-pumped solid-state lasers. A historical overview is presented of semiconductor diode-pumped solid-state lasers beginning with work in the early 1960s and continuing through recent work on wavelength extension of these devices by laser operation on new transitions. Modeling of these devices by rate equations to obtain expressions for threshold, slope efficiency, and figures of merit is also given.

Fan, Tso Yee; Byer, Robert L.

1988-01-01

111

Direct solar-pumped iodine laser amplifier  

NASA Technical Reports Server (NTRS)

This semiannual progress report covers the period from September 1, 1988 to February 28, 1989 under NASA grant NAG-1-441 entitled, Direct Solar-Pumped Iodine Laser Amplifier. During this period, the research effort was concentrated on the solar pumped master oscillator power amplifier (MOPA) system using n-C3F7I. In the experimental work, the amplification measurement was conducted to identify the optimum conditions for amplification of the center's Vortek solar simulator pumped iodine laser amplifier. A modeling effort was also pursued to explain the experimental results in the theoretical work. The amplification measurement of the solar simulator pumped iodine laser amplifier is the first amplification experiment on the continuously pumped amplifier. The small signal amplification of 5 was achieved for the triple pass geometry of the 15 cm long solar simulator pumped amplifier at the n-C3F7I pressure of 20 torr, at the flow velocity of 6 m/sec and at the pumping intensity of 1500 solar constants. The XeCl laser pumped iodine laser oscillator, which was developed in the previous research, was employed as the master oscillator for the amplification measurement. In the theoretical work, the rate equations of the amplifier was established and the small signal amplification was calculated for the solar simulator pumped iodine laser amplifier. The amplification calculated from the kinetic equations with the previously measured rate coefficients reveals very large disagreement with experimental measurement. Moreover, the optimum condition predicted by the kinetic equation is quite discrepant with that measured by experiment. This fact indicates the necessity of study in the measurement of rate coefficients of the continuously pumped iodine laser system.

Han, Kwang S.; Hwang, In Heon; Stock, Larry V.

1989-01-01

112

CW optically pumped molecular iodine laser  

Microsoft Academic Search

Laser oscillation on several molecular iodine transitions is observed. The unique feature of this laser is that it is excited by a CW optical pump, a single longitudinal mode Ar(+) laser, and that it exhibits CW oscillation on more than 100 individually selectable transitions spanning more than one octave from 0.57 to 1.35 microns. The characteristics of the molecular-iodine laser

J. B. Koffend; F. J. Wodarczyk; R. W. Field

1978-01-01

113

Solar simulator-pumped atomic iodine laser  

SciTech Connect

An atomic iodine laser, a candidate for the direct solar-pumped gas laser, was excited with a 4-kW beam from a xenon arc solar simulator. Continuous lasing at 1.315 ..mu..m for over 10 ms was obtained for static filling of n-C/sub 3/F/sub 7/I vapor. By momentarily flowing the lasant, a 30-Hz pulsed output was obtained for about 200 ms. The peak laser power observed was 4 W for which the system efficiency reached 0.1%. These results indicate that direct solar pumping of a gas laser for power conversion in space is indeed feasible.

Lee, J.H.; Weaver, W.R.

1981-07-15

114

Mather-type dense plasma focus as a new optical pump for short-wavelength high-power lasers  

SciTech Connect

For the first time, a Mather-type dense plasma focus (MDPF) is successfully operated as an optical pump for lasers. Rhodamine-6G dye is optically pumped using the MDPF fluorescence, producing a laser pulse 1 ..mu..s in duration and more than 50 kW in output power. No optimization is attempted either of the laser cavity or of the lasing medium concentration and volume. A brief description of the experimental setup is presented, along with a summary and discussion of the results. The advantages of the present optical pump source and, in particular, their implications for the pumping of short-wavelength lasers are discussed.

Fanning, J.J.; Kim, K.

1984-04-01

115

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

SciTech Connect

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.

Mandl, A.; Zavriyev, A.; Klimek, D.E. [Textron Systems Div., Wilmington, MA (United States)] [Textron Systems Div., Wilmington, MA (United States)

1996-10-01

116

Experimental investigations on energy-transfer characteristics and performance of some laser dye mixtures  

NASA Astrophysics Data System (ADS)

Energy transfer from both Coumarin 120 (C120) and p-Bis(o-methylstyryl)-benzene (Bis-MSB), energy donors, to coumarin 7(C7) (acceptor) individually has been studied by steady-state emission measurements in methanol. The dye laser characteristics of the above-mentioned dyes have also been studied with respect to the energy transfer mechanism in the same solvent using a pulsed nitrogen laser as a pumping source. The large values of the critical transfer distances, R0, indicate that the dominant mechanism responsible for energy transfer is due to long-range dipole-dipole interaction between the excited donor and ground state acceptor molecule. Both photophysical and photochemical stability of the donors has been examined under the effect of N 2 laser pumping.

Ghazy, R.; Zim, S. A.; Shaheen, M.; El-Mekawey, F.

2002-03-01

117

Exploding conducting film laser pumping apparatus  

DOEpatents

The 342-nm molecular iodine and the 1.315-..mu..m atomic iodine lasers have been optically pumped by intense light from exploding-metal-film discharges. Brightness temperatures for the exploding-film discharges were approximately 25,000 K. Although lower output energies were achieved for such discharges when compared to exploding-wire techniques, the larger surface area and smaller inductance inherent in the exploding-film should lead to improved efficiency for optically-pumped gas lasers.

Ware, K.D.; Jones, C.R.

1984-04-27

118

A continuously pumped iodine laser amplifier  

Microsoft Academic Search

The amplification characteristics were studied for a continuously pumped iodine laser amplifier using n-C3F7I as the amplifying medium. A small-signal amplification of 5 was obtained from a 15 cm long amplifier pumped with 1000 AM0 solar radiation by passing the oscillator output through the amplifier three times.

In Heon Hwang; Kwang S. Han

1991-01-01

119

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

NASA Astrophysics Data System (ADS)

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.

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

1995-03-01

120

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

SciTech Connect

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.

Mandl, A.; Zavriyev, A.; Klimek, D.E. [Textron Systems Div., Wilmington, MA (United States)] [Textron Systems Div., Wilmington, MA (United States)

1997-03-01

121

Research on solar pumped liquid lasers  

NASA Technical Reports Server (NTRS)

A solar pumped liquid laser that can be scaled up to high power (10 mW CW) for space applications was developed. Liquid lasers have the advantage over gases in that they provide much higher lasant densities and thus high-power densities. Liquids also have advantages over solids in that they have much higher damage thresholds and are much cheaper to produce for large scale applications. Among the liquid laser media that are potential candidates for solar pumping, the POC13: Nd sup 3+:ZrC14 liquid was chosen for its high intrinsic efficiency and its relatively good stability against decomposition due to protic contamination. The development of a manufacturing procedure and performance testing of the laser, liquid and the development of an inexpensive large solar concentrator to pump the laser are examined.

Cox, J. D.; Kurzweg, U. H.; Weinstein, N. H.; Schneider, R. T.

1985-01-01

122

Frequency stabilization of diode-laser-pumped solid state lasers  

NASA Technical Reports Server (NTRS)

The goal of the NASA Sunlite program is to fly two diode-laser-pumped solid-state lasers on the space shuttle and while doing so to perform a measurement of their frequency stability and temporal coherence. These measurements will be made by combining the outputs of the two lasers on an optical radiation detector and spectrally analyzing the beat note. Diode-laser-pumped solid-state lasers have several characteristics that will make them useful in space borne experiments. First, this laser has high electrical efficiency. Second, it is of a technology that enables scaling to higher powers in the future. Third, the laser can be made extremely reliable, which is crucial for many space based applications. Fourth, they are frequency and amplitude stable and have high temporal coherence. Diode-laser-pumped solid-state lasers are inherently efficient. Recent results have shown 59 percent slope efficiency for a diode-laser-pumped solid-state laser. As for reliability, the laser proposed should be capable of continuous operation. This is possible because the diode lasers can be remote from the solid state gain medium by coupling through optical fibers. Diode lasers are constructed with optical detectors for monitoring their output power built into their mounting case. A computer can actively monitor the output of each diode laser. If it sees any variation in the output power that might indicate a problem, the computer can turn off that diode laser and turn on a backup diode laser. As for stability requirements, it is now generally believed that any laser can be stabilized if the laser has a frequency actuator capable of tuning the laser frequency as far as it is likely to drift in a measurement time.

Byer, Robert L.

1988-01-01

123

Continuous wave optically pumped iodine monofluoride B /sup 3/Pi(0/sup +/). -->. X /sup 1/. sigma. /sup +/ laser  

SciTech Connect

A continuous wave optically pumped iodine monofluoride laser operating on the B /sup 3/Pi(0/sup +/) ..-->.. X /sup 1/..sigma../sup +/ system is described. The laser operated on a series of rovibronic lines originating from v' = 2--5. By tuning the dye laser pump source over a single rovibronic line, spectral structure was produced on the IF laser output that was analyzed and found to be consistent with hyperfine structure in IF. Hyperfine coupling constants were determined in this analysis. Implications for a chemically pumped IF laser are also presented.

Davis, S.J.; Hanko, L.; Wolf, P.J.

1985-06-01

124

Solar-pumped photodissociation iodine laser  

NASA Technical Reports Server (NTRS)

The scientific feasibility of a solar-pumped iodine photodissociation laser for space applications is under investigation. Recently, a 2-W CW output for more than one hour was achieved using n-C3F7I vapor as the laser material and a vortex-stabilized argon arc as the light source.

Lee, J. H.; Weaver, W. R.; Humes, D. H.; Williams, M. D.; Lee, M. H.

1986-01-01

125

Solar-pumped photodissociation iodine laser  

SciTech Connect

The scientific feasibility of a solar-pumped iodine photodissociation laser for space applications is under investigation. Recently, a 2-watt CW output for more than one hour was achieved using n-C/sub 3/F/sub 7/I vapor as the laser material and a vortex-stabilized argon arc as the light source.

Lee, J.H.; Weaver, W.R.; Humes, D.H.; Williams, M.D.; Lee, M.H.

1986-08-15

126

Solar-pumped photodissociation iodine laser @f|  

Microsoft Academic Search

The scientific feasibility of a solar-pumped iodine photodissociation laser for space applications is under investigation. Recently, a 2-watt CW output for more than one hour was achieved using n-C3F7I vapor as the laser material and a vortex-stabilized argon arc as the light source.

J. H. Lee; W. R. Weaver; D. H. Humes; M. D. Williams; M. H. Lee

1986-01-01

127

Semiconductor disk laser-pumped subpicosecond holmium fibre laser  

SciTech Connect

The first passively mode-locked holmium fibre laser has been demonstrated, with a semiconductor saturable absorber mirror (SESAM) as a mode locker. Semiconductor disk lasers have been used for the first time to pump holmium fibre lasers. We obtained 830-fs pulses at a repetition rate of 34 MHz with an average output power of 6.6 mW.

Chamorovskiy, A Yu; Marakulin, A V; Leinonen, T; Kurkov, Andrei S; Okhotnikov, Oleg G

2012-01-31

128

Applications of lasers and electro-optics  

Microsoft Academic Search

Supported by the IRPA Programme on Laser Technology and Applications, many types of lasers have been designed, constructed and applied in various areas of science, medicine and industries. Amongst these lasers constructed were high power carbon dioxide lasers, rare gas halide excimer lasers, solid state Neodymium-YAG lasers, nitrogen lasers, flashlamp pumped dye lasers and nitrogen and excimer laser pumped dye

B. C. Tan; K. S. Low; Y. H. Chen; Harith Ahmad; T. Y. Tou

1994-01-01

129

Direct solar-pumped iodine laser amplifier  

NASA Technical Reports Server (NTRS)

A XeCl laser pumped iodine laser oscillator was developed which will be incorporated into the Master Oscillator Power Amplifier (MOPA) system. The developed XeCl laser produces output energy of about 60 mJ per pulse. The pulse duration was about 10 nsec. The kinetic model for the solar-pumped laser was refined and the algorithm for the calculation of a set of rate equations was improved to increase the accuracy and the efficiency of the calculation. The improved algorithm was applied to explain the existing experimental data taken from a flashlamp pumped iodine laser for three kinds of lasants, i-C3F7I, n-C4F9I, and t-C4F9I. Various solid laser materials were evaluated for solar-pumping. The materials studied were Nd:YAG, Nd:YLF, and Cr:Nd:GSGG crystals. The slope efficiency of 0.17 percent was measured for the Nd:YLF near the threshold pump intensity which was 211 solar constants (29W/sq cm). The threshold pump intensity of the Nd:YAG was measured to be 236 solar constants (32W/sq cm) and the near-threshold slope efficiency was 0.12 percent. True CW laser operation of Cr:Nd:GSGG was possible only at pump intensities less than or equal to 1,500 solar constants (203 W/sq cm). This fact was attributed to the high thermal focusing effect of the Cr:Nd:GSGG rod.

Han, Kwang S.; Hwang, In Heon; Kim, Khong Hon; Stock, Larry V.

1988-01-01

130

Fluorescence enhancement monitoring of pyrromethene laser dyes by metallic Ag nanoparticles.  

PubMed

Fluorescence enhancement monitoring of pyrromethene laser dyes using their complexation with Ag nanoparticles (Ag NPs) was studied. The size of the prepared Ag NPs was determined by transmission electron spectroscopy and UV/Vis absorption spectroscopy. Mie theory was also used to confirm the size of NPs theoretically. The effect of different nanoparticle concentrations on the optical properties of 1 × 10(-4) ?M?PM dyes shows that 40%of Ag NPs concentration (40%C Ag NPs) in complex is the optimum concentration. Also, the effects of different concentrations of PM dyes in a complex was measured. Emission enhancement factors were calculated for all samples. Fluorescence enhancement efficiencies depended on the input pumping energy of a Nd-YAG laser (wavelength 532?nm and 8?ns pulse duration) were reported and showed the lowest energy (28 and 32?mJ) in the case of PM567 and PM597, respectively. Copyright © 2014 John Wiley & Sons, Ltd. PMID:24652745

Sakr, Mahmoud E M; Abou Kana, Maram T H; Abdel Fattah, Gamal

2014-11-01

131

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

SciTech Connect

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.

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

1987-09-01

132

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

PubMed

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

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

2002-03-20

133

Direct solar-pumped iodine laser amplifier  

NASA Technical Reports Server (NTRS)

A XeCl laser which was developed earlier for an iodine laser oscillator was modified in order to increase the output pulse energy of XeCl laser so that the iodine laser output energy could be increased. The electrical circuit of the XeCl laser was changed from a simple capacitor discharge circuit of the XeCl laser to a Marx system. Because of this improvement the output energy from the XeCl laser was increased from 60 mj to 80 mj. Subsequently, iodine laser output energy was increased from 100 mj to 3 mj. On the other hand, the energy storage capability and amplification characteristics of the Vortek solar simulator-pumped amplifier was calculated expecting the calculated amplification factor is about 2 and the energy extraction efficiency is 26 percent due to the very low input energy density to the amplifier. As a result of an improved kinetic modeling for the iodine solar simulator pumped power amplifier, it is found that the I-2 along the axis of the tube affects seriously the gain profile. For the gas i-C3F7I at the higher pressures, the gain will decrease due to the I-2 as the pumping intensity increases, and at these higher pressures an increase in flow velocity will increase the gain.

Han, Kwang S.; Hwang, In H.; Stock, Larry V.

1988-01-01

134

Solar Pumped Lasers and Their Applications  

NASA Technical Reports Server (NTRS)

Since 1980, NASA has been pursuing high power solar lasers as part of the space power beaming program. Materials in liquid, solid, and gas phases have been evaluated against the requirements for solar pumping. Two basic characteristics of solar insolation, namely its diffuse irradiance and 5800 K blackbody-like spectrum, impose rather stringent requirements for laser excitation. However, meeting these requirements is not insurmountable as solar thermal energy technology has progressed today, and taking advantage of solar pumping lasers is becoming increasingly attractive. The high density photons of concentrated solar energy have been used for mainly electric power generation and thermal processing of materials by the DOE Solar Thermal Technologies Program. However, the photons can interact with materials through many other direct kinetic paths, and applications of the concentrated photons could be extended to processes requiring photolysis, photosynthesis, and photoexcitation. The use of solar pumped lasers on Earth seems constrained by economics and sociopolitics. Therefore, prospective applications may be limited to those that require use of quantum effects and coherency of the laser in order to generate extremely high value products and services when conventional and inexpensive means are ineffective or impossible. The new applications already proposed for concentrated solar photons, such as destruction of hazardous waste, production of renewable fuel, production of fertilizer, and air/water pollution controls, may benefit from the use of inexpensive solar pumped laser matched with the photochemical kinetics of these processes.

Lee, Ja H.

1991-01-01

135

Studies of blackbody-pumped lasers  

NASA Technical Reports Server (NTRS)

Laser action was achieved in a large-scale pulsed system and meaningful experiments were carried out in the axial flow facility to understand the physics of solar-pumped lasers. Studies of the variation of laser mixture composition were done for mixtures of CO2 and N2O additions. Theoretical analysis and modeling of the system were also performed based on a model including radiative pumping, diffusion and wall deactivation, and vibrational energy transfer between two optically active species. Qualitative agreement between predictions in the parameter variation and the experimental results were obtained with CO and N2O mixtures. Several experimental studies were performed to quantify the properties of carbon monoxide as absorber and storage of energy in the blackbody pumped system.

Christiansen, W. H.; Chang, J.; Sirota, M.

1988-01-01

136

Direct solar-pumped iodine laser amplifier  

Microsoft Academic Search

This semiannual progress report covers the period from September 1, 1988 to February 28, 1989 under NASA grant NAG-1-441 entitled, Direct Solar-Pumped Iodine Laser Amplifier. During this period, the research effort was concentrated on the solar pumped master oscillator power amplifier (MOPA) system using n-C3F7I. In the experimental work, the amplification measurement was conducted to identify the optimum conditions for

Kwang S. Han; In Heon Hwang; Larry V. Stock

1989-01-01

137

Photosensitization method to improve lithotripsy with dye and alexandrite lasers  

NASA Astrophysics Data System (ADS)

Laser lithotripsy is based on laser induced plasma formation. Successful stone fragmenting is dependent on power density at the fiber tip in contact with the stone and on the absorption of laser radiation by the stone itself. The use of the laser has been ineffective in the treatment of hard stones and of stones that absorb only minimal amounts of laser radiation. In our experimental and clinical studies we used Rifamycin (Rifocin) as a photosensitizer for the pulsed Dye laser and Sterile Indocyanine Green (Cardio Green) for the pulsed Alexandrite laser. We found that the use of these substances significantly increased the effectiveness of the laser in the treatment of those stones.

Cecchetti, Walter; Tasca, Andrea; Guazzieri, Stefano; Zattoni, Filiberto; Pagano, Francesco

1993-05-01

138

Flashlamp-pumped iodine monobromide laser characteristics  

NASA Technical Reports Server (NTRS)

The operating characteristics of a flashlamp-pumped IBr laser were investigated to evaluate its suitability for solar-pumped laser applications. A peak power of 350 W/sq cm at 2.7 microns was achieved at 12-torr IBr pressure. At 500-J flashlamp energy, the IBr output saturated; a gain of 0.17% per cm was measured for IBr. Neon was found to be effective for enhancing the recombination of the photodissociation products. With neon as a buffer gas, the laser pulse length was extended to 53 microsec. The termination of the laser pulse, within the flashlamp pulse, is thought to be due to the temperature rise in the gas. Increasing the IBr initial temperature decreased the lasing output. At 300 C, output dropped to approximately one-half the room temperature value. The dominant quencher is thought to be atomic iodine. IBr was found to couple better to the flashlamp energy than C3F7I.

Zapata, L. E.; De Young, R. J.

1983-01-01

139

Solar pumped laser technology options for space power transmission  

NASA Technical Reports Server (NTRS)

An overview of long-range options for in-space laser power transmission is presented. The focus is on the new technology and research status of solar-pumped lasers and their solar concentration needs. The laser options include gas photodissociation lasers, optically-pumped solid-state lasers, and blackbody-pumped transfer lasers. The paper concludes with a summary of current research thrusts.

Conway, E. J.

1986-01-01

140

Heat pump processes induced by laser radiation  

NASA Technical Reports Server (NTRS)

A carbon dioxide laser system was constructed for the demonstration of heat pump processes induced by laser radiation. The system consisted of a frequency doubling stage, a gas reaction cell with its vacuum and high purity gas supply system, and provisions to measure the temperature changes by pressure, or alternatively, by density changes. The theoretical considerations for the choice of designs and components are dicussed.

Garbuny, M.; Henningsen, T.

1980-01-01

141

Microwave-pumped atomic gas laser  

Microsoft Academic Search

This patent describes a method of obtaining coherent optical or quasi-optical radiation from a chemical element whose first excited state is metastable. It includes: enclosing a solid compound containing the element in a gas-tight enclosure containing a buffer gas or mixture of gases; placing the enclosure in a microwave cavity and between laser mirrors; and pumping the compound with microwave

Bramley

1989-01-01

142

Theoretical studies of solar-pumped lasers  

NASA Technical Reports Server (NTRS)

Solar-pumped lasers were investigated by comparing experimental results from pulse experiments with steady state calculations. The time varying behavior of an IBr laser is studied. The analysis is only approximate, but indicates that conditions occurring in a pulsed experiment are quite different from those at steady state. The possibility of steady-state lasing in an IBr laser is determined. The effects of high temperatures on the quenching and recombination rates are examined. Although uncertainties in the values of the rate coefficients make it difficult to draw firm conclusions, it seems steady state running may be possible at high temperatures.

Harries, W. L.

1982-01-01

143

Theoretical studies of solar-pumped lasers  

SciTech Connect

Solar-pumped lasers were investigated by comparing experimental results from pulse experiments with steady state calculations. The time varying behavior of an IBr laser is studied. The analysis is only approximate, but indicates that conditions occurring in a pulsed experiment are quite different from those at steady state. The possibility of steady-state lasing in an IBr laser is determined. The effects of high temperatures on the quenching and recombination rates are examined. Although uncertainties in the values of the rate coefficients make it difficult to draw firm conclusions, it seems steady state running may be possible at high temperatures.

Harries, W.L.

1982-02-01

144

Prototype laser-diode-pumped solid state laser transmitters  

NASA Technical Reports Server (NTRS)

Monolithic, diode-pumped Nd:YAG ring lasers can provide diffraction-limited, single-frequency, narrow-linewidth, tunable output which is adequate for use as a local oscillator in a coherent communication system. A laser was built which had a linewidth of about 2 kHz, a power of 5 milliwatts, and which was tunable over a range of 30 MHz in a few microseconds. This laser was phase-locked to a second, similar laser. This demonstrates that the powerful technique of heterodyne detection is possible with a diode-pumped laser used as the local oscillator. Laser diode pumping of monolithic Nd:YAG rings can lead to output powers of hundreds of milliwatts from a single laser. A laser was built with a single-mode output of 310 mW. Several lasers can be chained together to sum their power, while maintaining diffraction-limited, single frequency operation. This technique was demonstrated with two lasers, with a total output of 340 mW, and is expected to be practical for up to about ten lasers. Thus with lasers of 310 mW, output of up to 3 W is possible. The chaining technique, if properly engineered, results in redundancy. The technique of resonant external modulation and doubling is designed to efficiently convert the continuous wave, infrared output of our lasers into low duty-cycle pulsed green output. This technique was verified through both computer modeling and experimentation. Further work would be necessary to develop a deliverable system using this technique.

Kane, Thomas J.; Cheng, Emily A. P.; Wallace, Richard W.

1989-01-01

145

Long-path absorption measurement of CO(2) with a Raman-shifted tunable dye laser.  

PubMed

A laser long-path absorption system was developed with a hydrogen Raman shifter pumped by a tunable dye laser. The absorption spectrum of CO(2) in the 2-µm region was measured in the open air with a retroreflector or a hard target. The concentration of CO(2) was determined from the spectrum by the least-squares method. Noise in the system was analyzed, and the propagation of error to the obtained concentration was investigated. The statistical error in the concentration was estimated at approximately 1% for a single spectrum measurement. Comparison with the simultaneous measurements with a nondispersive infrared gas analyzer showed good agreement. PMID:20856536

Sugimoto, N; Minato, A

1993-11-20

146

Room-temperature, continuous-wave, 946-nm Nd:YAG laser pumped by laser-diode arrays and intracavity frequency doubling to 473 nm  

SciTech Connect

We report the use of GaAlAs laser-diode arrays to pump a cw Nd:YAG laser operating on the 946-nm /sup 4/F/sub 3/2/..-->../sup 4/I/sub 9/2/ transition. At room temperature, the lasing threshold was reached with 58 mW of absorbed pump power, and, with 175 mW of absorbed pump power, 42 mW of output power at 946 nm was obtained in a TEM/sub 00/ mode by using 0.7% output coupling. In addition, pumping with an infrared dye laser operating in a pure TEM/sub 00/ mode was used to investigate the effects of reabsorption loss that are characteristic of the 946-nm laser transition. LiIO/sub 3/ was used as an intracavity doubling crystal, and 100 ..mu..W of blue light was generated by using diode-laser pumping in a nonoptimized cavity.

Risk, W.P.; Lenth, W.

1987-12-01

147

Efficient pumping of inertial fusion energy lasers  

NASA Astrophysics Data System (ADS)

Solid-state lasers have been demonstrated as attractive drivers for laser-plasma interaction and have presently been developed for various applications like inertial confinement fusion (ICF) [1], particle acceleration and intense X-ray generation [3]. Viable real world applications like power production at industrial scale will require high laser system efficiency, repetition rate and lifetime which are only possible with semiconductor diode pumping. The paper describes the work conducted with two 20 kW diode laser sources pumping an ytterbium:YAG laser amplifier. The set-up acts as a small scale prototype for the DiPOLE project [2]. This project aims to develop scalable gas cooled cryogenic multi-slab diode pumped solid state lasers capable of producing KJ pulse energy. A scale-down prototype is currently under development at the Central Laser Facility (CLF) designed to generate 10 J at 10 Hz. To secure an efficient pumping process the sources have to fulfill aside power requirement in the spectral and time domain, the claim for high homogenization and low divergence of the spatial and angular beam distribution as well as a minimization of losses within the optical path. The existing diode laser sources designed and built by INGENERIC deliver 20 kW pulsed power, concentrated on a plateau of FWHM dimension of 20 x 20 mm² with a homogeneity of more than 90 %. The center wavelength of 939.5 nm is controlled in a range of ± 0.1 nm. The time and area integrated spectrum of at least 76 % of the total energy is contained within a 6 nm wide wavelength band around the center wavelength. Repetition rates can be adjusted between 0.1 Hz up to 10 Hz with rise and fall times less than 50 ?s and pulse durations from 0.2 ms to 1.2 ms. The paper describes the impact of different designs on the performance of pump sources and puts special emphasis on the influence of the optical components on efficiency and performance. In addition the influence of the measuring principle is discussed.

Wessling, C.; Rübenach, O.; Hambücker, S.; Sinhoff, V.; Banerjeea, S.; Ertel, K.; Mason, P.

2013-02-01

148

Continuous-wave-fiber-laser-pumped Ti:sapphire laser  

Microsoft Academic Search

We report the first experimental demonstration of a high-power Ti:sapphire laser pumped by an efficient, compact and cost-effective continuous-wave (cw) fiber-laser-green source at 532 nm. The green source is obtained by direct singlepass second-harmonic-generation (SHG) of a Yb-fiber laser in MgO:sPPLT crystal, providing 11 W of green power in TEM00 spatial profile. The Ti:sapphire laser is continuously tunable across 743-970

Kavita Devi; S. Chaitanya Kumar; G. K. Samanta; M. Ebrahim-Zadeh

2010-01-01

149

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

DOEpatents

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.

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

1993-10-26

150

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

DOEpatents

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.

Field, George F. (Danville, CA); Hammond, Peter R. (Livermore, CA)

1993-01-01

151

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

SciTech Connect

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)

Alimov, O K [Institute of Nuclear Physics, Academy of Sciences of Uzbekistan, Tashkent (Uzbekistan); Basiev, T T; Orlovskii, Yu V; Osiko, V V [Laser Materials and Technology Research Center, A. M. Prokhorov General Physics Institute, Russian Academy of Sciences, Moscow (Russian Federation); Samoilovich, M I [Tekhnomash Central Research Technological Institute, Moscow (Russian Federation)

2008-07-31

152

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

NASA Technical Reports Server (NTRS)

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.

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

1986-01-01

153

UV laser interaction with a fluorescent dye solution studied using pulsed digital holography.  

PubMed

A frequency tripled Q-switched Nd-YAG laser (wavelength 355 nm, pulse duration 12 ns) has been used to pump Coumarin 153 dye solved in ethanol. Simultaneously, a frequency doubled pulse (532 nm) from the same laser is used to probe the solvent perpendicularly resulting in a gain through stimulated laser induced fluorescence (LIF) emission. The resulting gain of the probe beam is recorded using digital holography by blending it with a reference beam on the detector. Two digital holograms without and with the pump beam were recorded. Intensity maps were calculated from the recorded digital holograms and used to calculate the gain of the probe beam due to the stimulated LIF. In addition numerical data of the local temperature rise was calculated from the corresponding phase maps using Radon inversion. It was concluded that about 15% of the pump beam energy is transferred to the dye solution as heat while the rest is consumed in the radiative process. The results show that pulsed digital holography is a promising technique for quantitative study of fluorescent species. PMID:24150372

Amer, Eynas; Gren, Per; Sjödahl, Mikael

2013-10-21

154

Terahertz graphene lasers: Injection versus optical pumping  

SciTech Connect

We analyze the formation of nonequilibrium states in optically pumped graphene layers and in forward-biased graphene structures with lateral p-i-n junctions and consider the conditions of population inversion and lasing. The model used accounts for intraband and interband relaxation processes as well as deviation of the optical phonon system from equilibrium. As shown, optical pumping suffers from a significant heating of both the electron-hole plasma and the optical phonon system, which can suppress the formation of population inversion. In the graphene structures with p-i-n junction, the injected electrons and holes have relatively low energies, so that the effect of cooling can be rather pronounced, providing a significant advantage of the injection pumping in realization of graphene terahertz lasers.

Ryzhii, Victor; Otsuji, Taiichi [Research Institute for Electrical Communication, Tohoku University, Sendai 980-8577 (Japan); Ryzhii, Maxim [Computational Nanoelectronics Laboratory, University of Aizu, Aizu-Wakamatsu 965-8580 (Japan); Mitin, Vladimir [Department of Electrical Engineering, University at Buffalo, SUNY, Buffalo, New York 14260-1920 (United States)

2013-12-04

155

Solar-pumped gas laser development  

NASA Technical Reports Server (NTRS)

A survey of gas properties through detailed kinetic models led to the identification of critical gas parameters for use in choosing appropriate gas combinations for solar pumped lasers. Broadband photoabsorption in the visible or near UV range is required to excite large volumes of gas and to insure good solar absorption efficiency. The photoexcitation density is independent of the absorption bandwidth. The state excited must be a metastable state which is not quenched by the parent gas. The emission bandwidth must be less than 10 A to insure lasing threshold over reasonable gain lengths. The system should show a high degree of chemical reversibility and an insensitivity to increasing temperature. Other properties such as good quantum efficiency and kinetic efficiency are also implied. Although photoexcitation of electronic vibrational transitions is considered as a possible system if the emission bands sufficiently narrow, it appears that photodissociation into atomic metastables is more likely to result in a successful solar pumped laser system.

Wilson, J. W.

1980-01-01

156

New laser dye systems based on transition metal complexes  

NASA Astrophysics Data System (ADS)

Excited state properties of luminescent ruthenium (II) complexes and their interactions with laser dyes, other metal complexes, and oxygen have been studied in both homogeneous and surfactant containing solutions and in solid polymer matrices. Low cost experimental tools have been developed to facilitate these studies. These include a low cost temperature controller, a simple deoxygenation cell for surfactant solutions, and a low frequency computerized lockin amplifier. Also, new quantum counters for light intensity measurements have been developed. Energy transfer from ruthenium (II) complexes to a variety of rhodamine and oxazine laser dyes has been demonstrated in both homogeneous solutions and in surfactant-assisted ones. Singlet energy transfer efficiencies from the charge transfer (CT) sensitizing state of the Ru(II) complex to the laser dyes in homogeneous solutions are unity, and in surfactant-assisted systems efficiencies are 45-75% at concentrations of 10-5M.

Demas, J. N.

1982-05-01

157

Solar-pumped laser for free space power transmission  

NASA Technical Reports Server (NTRS)

Laser power transmission; laser systems; space-borne and available lasers; 2-D and 1 MW laser diode array systems; technical issues; iodine solar pumped laser system; and laser power transmission applications are presented. This presentation is represented by viewgraphs only.

Lee, Ja H.

1989-01-01

158

Low threshold solar-pumped iodine laser  

Microsoft Academic Search

Solar-pumped lasing of i-C3F7I and n-C4F9I at lower solar concentrations (170 solar constants) and longer gain lengths than previous solar lasers is demonstrated, with potential application to the lasing needs of space. Two xenon arc solar simulators provide an AM0 spectrum over the 60-cm gain length, and output pulse energies of 70 mJ and an average power of 550 mW

R. J. Deyoung

1986-01-01

159

Efficiency and threshold pump intensity of CW solar-pumped solid-state lasers  

NASA Technical Reports Server (NTRS)

The authors consider the relation between the threshold pumping intensity, the material properties, the resonator parameters, and the ultimate slope efficiencies of various solid-state laser materials for solar pumping. They clarify the relation between the threshold pump intensity and the material parameters and the relation between the ultimate slope efficiency and the laser resonator parameters such that a design criterion for the solar-pumped solid-state laser can be established. Among the laser materials evaluated, alexandrite has the highest slope efficiency of about 12.6 percent; however, it does not seem to be practical for a solar-pumped laser application because of its high threshold pump intensity. Cr:Nd:GSGG is the most promising for solar-pumped lasing. Its threshold pump intensity is about 100 air-mass-zero (AM0) solar constants and its slope efficiency is about 12 percent when thermal deformation is completely prevented.

Hwang, In H.; Lee, Ja H.

1991-01-01

160

Semiconductor Laser Diode Pumps for Inertial Fusion Energy Lasers  

SciTech Connect

Solid-state lasers have been demonstrated as attractive drivers for inertial confinement fusion on the National Ignition Facility (NIF) at Lawrence Livermore National Laboratory (LLNL) and at the Omega Facility at the Laboratory for Laser Energetics (LLE) in Rochester, NY. For power plant applications, these lasers must be pumped by semiconductor diode lasers to achieve the required laser system efficiency, repetition rate, and lifetime. Inertial fusion energy (IFE) power plants will require approximately 40-to-80 GW of peak pump power, and must operate efficiently and with high system availability for decades. These considerations lead to requirements on the efficiency, price, and production capacity of the semiconductor pump sources. This document provides a brief summary of these requirements, and how they can be met by a natural evolution of the current semiconductor laser industry. The detailed technical requirements described in this document flow down from a laser ampl9ifier design described elsewhere. In brief, laser amplifiers comprising multiple Nd:glass gain slabs are face-pumped by two planar diode arrays, each delivering 30 to 40 MW of peak power at 872 nm during a {approx} 200 {micro}s quasi-CW (QCW) pulse with a repetition rate in the range of 10 to 20 Hz. The baseline design of the diode array employs a 2D mosaic of submodules to facilitate manufacturing. As a baseline, they envision that each submodule is an array of vertically stacked, 1 cm wide, edge-emitting diode bars, an industry standard form factor. These stacks are mounted on a common backplane providing cooling and current drive. Stacks are conductively cooled to the backplane, to minimize both diode package cost and the number of fluid interconnects for improved reliability. While the baseline assessment in this document is based on edge-emitting devices, the amplifier design does not preclude future use of surface emitting diodes, which may offer appreciable future cost reductions and increased reliability. The high-level requirements on the semiconductor lasers involve reliability, price points on a price-per-Watt basis, and a set of technical requirements. The technical requirements for the amplifier design in reference 1 are discussed in detail and are summarized in Table 1. These values are still subject to changes as the overall laser system continues to be optimized. Since pump costs can be a significant fraction of the overall laser system cost, it is important to achieve sufficiently low price points for these components. At this time, the price target for tenth-of-akind IFE plant is $0.007/Watt for packaged devices. At this target level, the pumps account for approximately one third of the laser cost. The pump lasers should last for the life of the power plant, leading to a target component lifetime requirement of roughly 14 Ghosts, corresponding to a 30 year plant life and 15 Hz repetition rate. An attractive path forward involes pump operation at high output power levels, on a Watts-per-bar (Watts/chip) basis. This reduces the cost of pump power (price-per-Watt), since to first order the unit price does not increase with power/bar. The industry has seen a continual improvement in power output, with current 1 cm-wide bars emitting up to 500 W QCW (quasi-continuous wave). Increased power/bar also facilitates achieving high irradiance in the array plane. On the other hand, increased power implies greater heat loads and (possibly) higher current drive, which will require increased attention to thermal management and parasitic series resistance. Diode chips containing multiple p-n junctions and quantum wells (also called nanostack structures) may provide an additional approach to reduce the peak current.

Deri, R J

2011-01-03

161

Optically pumped mid-infrared vibrational hydrogen chloride laser  

Microsoft Academic Search

The results of an experimental investigation of an optically pumped vibrational laser in HCl are reported. Two different excitation sources were used: a Nd:yttrium–aluminum–garnet laser pumped optical parametric oscillator and a Raman shifted alexandrite laser. Overtone pumping on the (2,0) and (3,0) bands was employed to produce laser oscillation on the (3,2) and (2,1) bands near 3.8 ?m. We also

Harold C. Miller; John McCord; Gordon D. Hager; Steven J. Davis; William J. Kessler; David B. Oakes

1998-01-01

162

Optically pumped mid-infrared vibrational hydrogen chloride laser  

Microsoft Academic Search

The results of an experimental investigation of an optically pumped vibrational laser in HCl are reported. Two different excitation sources were used: a Nd:yttrium-aluminum-garnet laser pumped optical parametric oscillator and a Raman shifted alexandrite laser. Overtone pumping on the (2,0) and (3,0) bands was employed to produce laser oscillation on the (3,2) and (2,1) bands near 3.8 mum. We also

Harold C. Miller; John McCord; Gordon D. Hager; Steven J. Davis; William J. Kessler; David B. Oakes

1998-01-01

163

In-well pumping of InGaN/GaN vertical-external-cavity surface-emitting lasers  

NASA Astrophysics Data System (ADS)

In-well-pumped blue InGaN/GaN vertical-external-cavity surface-emitting lasers are demonstrated. The laser structures were grown on bulk GaN substrates by using metal-organic vapor phase epitaxy near atmospheric pressure. The active zone consisted of up to 20 InGaN quantum wells distributed in a resonant periodic gain configuration. High-reflectivity dielectric distributed Bragg-reflectors were used as mirrors. Laser emission with a single longitudinal mode at 440 nm was achieved by exclusively pumping the quantum wells with the 384 nm emission line of a dye-/N2-laser.

Wunderer, Thomas; Northrup, John E.; Yang, Zhihong; Teepe, Mark; Strittmatter, André; Johnson, Noble M.; Rotella, Paul; Wraback, Michael

2011-11-01

164

Efficient flashlamp-pumped IBr laser  

SciTech Connect

The operating characteristics and scaling parameters of a flashlamp-pumped, 4-m-long IBr laser were investigated to further evaluate its potential as a solar-pumped laser. A peak power of 3 kW/cm/sup 2/ at 2.7 ..mu..m was achieved at 4-Torr IBr pressure. A gain of 0.07 m/sup -1/ was measured at a maximum capacitor discharge energy of 4 kJ. The threshold input power necessary for lasing was found to decrease by a factor of 4 and the laser pulse width increased fourfold as the active gain length was increased from 1 to 4 m. A maximum pulse width of 120 ..mu..s was achieved with 10-Torr argon diluent added to 4-Torr IBr. Quenching of the excited state by the parent molecule was shown to be unimportant for pressures less than 4-Torr IBr. An intrinsic efficiency in the range of 12% has been measured for flashlamp-pumped IBr.

Zapata, L.E.; De Young, R.J.

1985-02-01

165

Optically (solar) pumped oxygen-iodine lasers  

NASA Astrophysics Data System (ADS)

We present the results of theoretical and experimental studies demonstrating the possibility of developing an oxygen-iodine laser (OIL) with direct optical pumping of molecular oxygen involving inter-molecular interaction with charge transfer from donor molecule (buffer gas) to acceptor molecule (oxygen). This interaction lifts degeneracy of the lower energy states of molecular oxygen and increases its absorption cross section in the visible spectral region and the UV Herzberg band, where high quantum yield of singlet oxygen is achieved (QY ˜ 1 and QY ˜ 2, respectively) at the same time. A pulse-periodic optical pump sources with pulse energy of ˜50 kJ, pulse duration of ˜25 ?s, and repetition rate of ˜10 Hz, which are synchronized with the mechanism of singlet oxygen generation, are developed. This allows implementation of a pulse-periodic oxygen-iodine laser with an efficiency of ˜25%, optical efficiency of ˜40%, and parameter L/ T ˜ 1/1.5, where T is the thermal energy released in the laser active medium upon generation of energy L. It is demonstrated that, under direct solar pumping of molecular oxygen, the efficiency parameter of the OIL can reach L/ T ˜ 1/0.8 in a wide range of scaling factors.

Danilov, O. B.; Zhevlakov, A. P.; Yur'ev, M. S.

2014-07-01

166

Applications for reactor-pumped lasers  

SciTech Connect

Nuclear reactor-pumped lasers (RPLs) have been developed in the US by the Department of Energy for over two decades, with the primary research occurring at Sandia National Laboratories and Idaho National Engineering Laboratory. The US program has experimentally demonstrated reactor-pumped lasing in various mixtures of xenon, argon, neon, and helium at wavelengths of 585, 703, 725, 1,271, 1,733, 1,792, 2,032, 2,630, 2,650, and 3,370 nm with intrinsic efficiency as high as 2.5%. The major strengths of a reactor-pumped laser are continuous high-power operation, modular construction, self-contained power, compact size, and a variety of wavelengths (from visible to infrared). These characteristics suggest numerous applications not easily accessible to other laser types. The continuous high power of an RPL opens many potential manufacturing applications such as deep-penetration welding and cutting of thick structures, wide-area hardening of metal surfaces by heat treatment or cladding application, wide-area vapor deposition of ceramics onto metal surfaces, production of sub-micron sized particles for manufacturing of ceramics, and 3-D ceramic lithography. In addition, a ground-based RPL could beam its power to space for such activities as illuminating geosynchronous communication satellites in the earth`s shadow to extend their lives, beaming power to orbital transfer vehicles, removing space debris, and providing power (from earth) to a lunar base during the long lunar night.

Lipinski, R.J.; McArthur, D.A. [Sandia National Labs., Albuquerque, NM (United States). Nuclear Systems Research

1994-10-01

167

Scalable pump source for diode pumped alkali laser  

NASA Astrophysics Data System (ADS)

External cavity diode laser systems are well-suited for diode pumped alkali laser (DPAL) systems due to their high power efficiency and excellent wavelength control under changing thermal loads. By conditioning the characteristics of feedback power, external cavities can narrow the spectral bandwidth and limit transverse modes of diode laser bars. Existing configurations typically use low-efficiency diffraction gratings at the Littrow angle to send back to the diodes a small fraction of the power, while directing the majority of the power forward in the output beam. We previously reported that a stepped mirror allows a single external cavity to condition the output beams of a stack of diode array bars. In this report, we describe a new approach that could use a single external cavity to condition the output beams of several hundred diode array bars. A high efficiency grating is used to feedback essentially all the power in the external cavity, and power splitters then distribute the power to multiple diode array stacks. A 384 bar module capable of 20 kW power output into a modelimited slowly diverging beam with a spectral width below 0.050 nm has been designed and proposed for use in a DPAL. A 50 bar 3 kW prototype is currently being assembled.

Hersman, F. W.; Distelbrink, J. H.; Ketel, J.; Sargent, D.; Watt, D. W.

2014-02-01

168

Random fiber laser of POSS solution-filled hollow optical fiber by end pumping  

NASA Astrophysics Data System (ADS)

Random fiber laser is obtained by end pumping a hollow optical fiber (HOF) filled with a dispersive solution of polyhedral oligomeric silsesquioxanes (POSS) nanoparticles and laser dye pyrromethene 597 (PM597) in carbon disulfide (CS2), in which the concentration is 1.5×10-2 M for PM597 and 18.5 wt% for POSS, respectively. It is found that the pump light at the one end of the liquid core optical fiber (LCOF) can pass the whole length of LCOF because the POSS nanoparticles were dispersed in CS2 at a molecular level (1-3 nm) with high stability and without sedimentation. Above the threshold pump energy (˜0.81 mJ) the random fiber laser appears coherent and resonant feedback multimode lasing in the weakly scattering system. For the LCOF containing PM597 with the same concentration and no POSS nanoparticles, there occurs only ASE that can be observed under the same experimental condition.

Hu, Zhijia; Zheng, Hongjun; Wang, Lijuan; Tian, Xiujie; Wang, Tongxin; Zhang, Qijin; Zou, Gang; Chen, Yang; Zhang, Qun

2012-09-01

169

Flashlamp-pumped iodine monobromide laser characteristics  

SciTech Connect

The operating characteristics of a flashlamp-pumped IBr laser were investigated to evaluate its suitability for solar-pumped laser applications. A peak power of 350 W/cm/sup 2/ at 2.7 ..mu..m was achieved at 12-Torr IBr pressure. At 500-J flashlamp energy, the IBr output saturated; a gain of 0.17% cm/sup -1/ was measured for IBr. Neon was found to be effective for enhancing the recombination of the photodissociation products. With neon as a buffer gas, the laser pulse length was extended to 53 ..mu..sec. The termination of the laser pulse, within the flashlamp pulse, is thought to be due to the temperature rise in the gas. Increasing the IBr initial temperature decreased the lasing output. At 300 /sup 0/C, output dropped to approximately one-half the room temperature value. The dominant quencher is thought to be atomic iodine. IBr was found to couple better to the flashlamp energy than C/sub 3/F/sub 7/I.

Zapata, L.E.; De Young, R.J.

1983-04-01

170

Amplified spontaneous emission in solar-pumped iodine laser  

NASA Technical Reports Server (NTRS)

The amplified spontaneous emission (ASE) from a long pulse, solar-simulating radiation pumped iodine laser amplifier is studied. The ASE threshold pump intensity is almost proportional to the inverse of the laser gain length when the gas pressure is constant in the laser tube.

Cho, Yong S.; Hwang, In H.; Han, Kwang S.; Lee, Ja H.

1992-01-01

171

End-Pumped Nd:BEL Laser Performance.  

National Technical Information Service (NTIS)

Performance data for a cw Nd:BEL laser end pumped by two 500 mW laser diode arrays are presented and compared with the performance data for a Nd:YAG laser in a similar configuration. The phased arrays used as the pump source are cooled by a temperature-co...

D. F. Heller, E. J. Schimitschek, J. Myers, R. Scheps

1988-01-01

172

Comparison of the performance of photonic band-edge liquid crystal lasers using different dyes as the gain medium  

NASA Astrophysics Data System (ADS)

The primary concern of this work is to study the emission characteristics of a series of chiral nematic liquid crystal lasers doped with different laser dyes (DCM, pyrromethene 580, and pyrromethene 597) at varying concentrations by weight (0.5-2 wt %) when optically pumped at 532 nm. Long-wavelength photonic band-edge laser emission is characterized in terms of threshold energy and slope efficiency. At every dye concentration investigated, the pyrromethene 597-doped lasers exhibit the highest slope efficiency (ranging from 15% to 32%) and the DCM-doped lasers the lowest (ranging from 5% to 13%). Similarly, the threshold was found to be, in general, higher for the DCM-doped laser samples in comparison to the pyrromethene-doped laser samples. These results are then compared with the spectral properties, quantum efficiencies and, where possible, fluorescence lifetimes of the dyes dispersed in a common nematic host. In accordance with the low thresholds and high slope efficiencies, the results show that the molar extinction coefficients and quantum efficiencies are considerably larger for the pyrromethene dyes in comparison to DCM, when dispersed in the liquid crystal host.

Mowatt, Carrie; Morris, Stephen M.; Song, Myoung Hoon; Wilkinson, Timothy D.; Friend, Richard H.; Coles, Harry J.

2010-02-01

173

Single mode coupled optofluidic ring resonator dye lasers  

Microsoft Academic Search

The authors demonstrate the single mode dye laser from a coupled optofluidic ring resonator that consists of a cylindrical ring resonator fused onto the inner surface of a thin-walled capillary ring resonator. The whispering gallery modes in each ring resonator interact strongly and utilize the Vernier effect to generate single mode laser emission. The lasing threshold is 3.0 muJ\\/mm2. The

Xiang Wu; Yuze Sun; Jonathan D. Suter; Xudong Fan

2009-01-01

174

Single mode coupled optofluidic ring resonator dye lasers  

NASA Astrophysics Data System (ADS)

The authors demonstrate the single mode dye laser from a coupled optofluidic ring resonator that consists of a cylindrical ring resonator fused onto the inner surface of a thin-walled capillary ring resonator. The whispering gallery modes in each ring resonator interact strongly and utilize the Vernier effect to generate single mode laser emission. The lasing threshold is 3.0 ?J/mm2. The light can be coupled out through an optical taper in contact with the capillary.

Wu, Xiang; Sun, Yuze; Suter, Jonathan D.; Fan, Xudong

2009-06-01

175

''Stenungsund-77'': Smoke Plume Measurements with a Pulsed Dye Laser.  

National Technical Information Service (NTIS)

This report describes some of the results obtained in a field experiment at Stenungsund in May 1977, under the support and coordination of the Swedish Space Corporation. We made lidar measurements with a pulsed tunable dye laser working at wavelengths in ...

G. Gustafsson, B. Hartmann, G. Spangstedt, O. Steinvall

1977-01-01

176

Iodine laser pumped by solar radiation  

SciTech Connect

An analysis is made of the use of solar radiation in space to pump a cw gas-flow iodine laser emitting at 1.3 ..mu... It is shown that the high probability of dissociation of I/sub 2/ molecules by solar radiation at an iodide vapor pressure of 0.25--0.5 kPa when the degree of concentration of solar radiation is 100--200 removes the constraint on the maximum duration of irradiation of the laser iodide associated with quenching of I(/sup 2/P/sub 1/2/) by I/sub 2/ molecules. In this case, the maximum duration of irradiation is governed by heating and pyrolysis. Numerical calculations and analytical estimates are used to analyze three variants of a solar-pumped iodine laser: using pure CF/sub 3/I iodide purified from I/sub 2/, using a CF/sub 3/I--(CF/sub 3/N)/sub 2/ mixture not purified from I/sub 2/, and using (CF/sub 3/)/sub 3/ CI not purified from I/sub 2/. Problems of circulation, purification, cooling, and irradiation of the active gas are examined.

Zalesskii, V.Y.

1983-06-01

177

DOE reactor-pumped laser program  

SciTech Connect

FALCON is a high-power, steady-state, nuclear reactor-pumped laser (RPL) concept that is being developed by the Department of Energy. The FALCON program has experimentally demonstrated reactor-pumped lasing in various mixtures of xenon, argon, neon, and helium at at wavelengths of 585, 703, 725, 1271, 1733, 1792, 2032, 2630, 2650, and 3370 nm with intrinsic efficiency as high as 2.5%. The major strengths of a reactor-pumped laser are continuous high-power operation, modular construction, self-contained power, compact size, and a variety of wavelengths (from visible to infrared). These characteristics suggest numerous applications not easily accessible to other laser types. A ground-based RPL could beam its power to space for such activities as illuminating geosynchronous communication satellites in the earth`s shadow to extend their lives, beaming power to orbital transfer vehicles, removing space debris, and providing power (from earth) to a lunar base during the long lunar night. The compact size and self-contained power also makes an RPL very suitable for ship basing so that power-beaming activities could be situated around the globe. The continuous high power of an RPL opens many potential manufacturing applications such as deep-penetration welding and cutting of thick structures, wide-area hardening of metal surfaces by heat treatment or cladding application, wide-area vapor deposition of ceramics onto metal surfaces, production of sub-micron sized particles for manufacturing of ceramics, wide-area deposition of diamond-like coatings, and 3-D ceramic lithography.

Felty, J.R. [USDOE, Germantown, MD (United States). Defense Programs; Lipinski, R.J.; McArthur, D.A.; Pickard, P.S. [Sandia National Labs., Albuquerque, NM (United States)

1993-12-31

178

DOE reactor-pumped laser program  

SciTech Connect

FALCON is a high-power, steady-state, nuclear reactor-pumped laser (RPL) concept that is being developed by the Department of Energy. The FALCON program has experimentally demonstrated reactor-pumped lasing in various mixtures of xenon, argon, neon, and helium at wavelengths of 585, 703, 725, 1271, 1733, 1792, 2032, 2630, 2650, and 3370 nm with intrinsic efficiency as high as 2.5%. The major strengths of a reactor-pumped laser are continuous highpower operation, modular construction, self-contained power, compact size, and a variety of wavelengths (from visible to infrared). These characteristics suggest numerous applications not easily accessible to other laser types. A ground-based RPL could beam its power to space for such activities as illuminating geosynchronous communication satellites in the earth`s shadow to extend their lives, beaming power to orbital transfer vehicles, removing space debris, and providing power (from earth) to a lunar base during the long lunar night. The compact size and self-contained power also makes an RPL very suitable for ship basing so that power-beaming activities could be situated around the globe. The continuous high power of an RPL opens many potential manufacturing applications such as deep-penetration welding and cutting of thick structures, wide-area hardening of metal surfaces by heat treatment or cladding application, wide-area vapor deposition of ceramics onto metal surfaces, production of sub-micron sized particles for manufacturing of ceramics, wide-area deposition of diamond-like coatings, and 3-D ceramic lithography.

Felty, J.R. [Department of Energy, Germantown, MD (United States). Defense Programs; Lipinski, R.J.; McArthur, D.A.; Pickard, P.S. [Sandia National Labs., Albuquerque, NM (United States). Nuclear Systems Research

1994-12-31

179

Fissioning uranium plasmas and nuclear-pumped lasers  

NASA Technical Reports Server (NTRS)

Current research into uranium plasmas, gaseous-core (cavity) reactors, and nuclear-pumped lasers is discussed. Basic properties of fissioning uranium plasmas are summarized together with potential space and terrestrial applications of gaseous-core reactors and nuclear-pumped lasers. Conditions for criticality of a uranium plasma are outlined, and it is shown that the nonequilibrium state and the optical thinness of a fissioning plasma can be exploited for the direct conversion of fission fragment energy into coherent light (i.e., for nuclear-pumped lasers). Successful demonstrations of nuclear-pumped lasers are described together with gaseous-fuel reactor experiments using uranium hexafluoride.

Schneider, R. T.; Thom, K.

1975-01-01

180

Theoretical and experimental studies of optically pumped molecular gas lasers.  

E-print Network

??Optically pumped molecular gas lasers based on vibrational-rotational transitions in the infrared spectral region were studied experimentally and theoretically. A model was developed to predict… (more)

Amarin, Ratanavis

2010-01-01

181

On the flow and thermal characteristics of high Reynolds numbers (2800-17000) dye cell: simulation and experiment  

E-print Network

This paper presents computational and experimental studies on wavelength/frequency fluctuation characteristics of high pulse repetition rate (PRR: 18 kHz) dye laser pumped by frequency doubled Nd:YAG laser (532 nm). The temperature gradient in the dye solution is found to be responsible for wavelength fluctuations of the dye laser at low flow rates (2800cells for high PRR pumping.

Mishra, G K; Prakash, O; Biswal, R; Dixit, S K; Nakhe, S V

2014-01-01

182

Fiber-laser-pumped Ti:sapphire laser  

E-print Network

We report the first experimental demonstration of efficient and high-power operation of a Ti:sapphire laser pumped by a simple, compact, continuous-wave (cw) fiber-laser-based green source. The pump radiation is obtained by direct single-pass second-harmonic-generation (SHG) of a 33-W, cw Yb-fiber laser in 30-mm-long MgO:sPPLT crystal, providing 11 W of single-frequency green power at 532 nm in TEM00 spatial profile with power and frequency stability better than 3.3% and 32 MHz, respectively, over one hour. The Ti:sapphire laser is continuously tunable across 743-970 nm and can deliver an output power up to 2.7 W with a slope efficiency as high as 32.8% under optimum output coupling of 20%. The laser output has a TEM00 spatial profile with M2<1.44 across the tuning range and exhibits a peak-to-peak power fluctuation below 5.1% over 1 hour.

Samanta, G K; Devi, Kavita; Ebrahim-Zadeh, M

2010-01-01

183

Interface module for transverse energy input to dye laser modules  

DOEpatents

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.

English, Jr., Ronald E. (Tracy, CA); Johnson, Steve A. (Tracy, CA)

1994-01-01

184

Pumping scheme dependent multimode laser emission from free-standing cylindrical microcavity  

NASA Astrophysics Data System (ADS)

We report the observation of multimode laser emission from a free-standing microring cavity based on rhodamine 6G dye doped hollow poly(methyl methacrylate) optical fiber (DDHPOF) obtained by pulsed photo-excitation. Two different pumping schemes were employed to characterize DDHPOF; the stripe illumination and the spot illumination. By using spot illumination, the slope efficiency of system is enhanced by more than 3 times than that of the stripe illumination and also a red-shift in emission spectrum is observed with the pump power. When the pump power is increased beyond the threshold value, laser emission occurs with a multimode structure. From the relation between mode spacing and diameter of cylindrical cavity, the lasing action is considered to be formed by whispering gallery modes (WGMs).

Peter, Jaison; Saleem, Rasool; Sebastian, Ananthu; Radhakkrishnan, P.; Nampoori, V. P. N.; Girijavallabhan, C. P.; Kailasnath, M.

2014-06-01

185

Nuclear pumped laser research at the Jet Propulsion Laboratory  

NASA Technical Reports Server (NTRS)

Using a partially nuclear excited xenon flashlamp to pump an iodine laser, laser pulse shapes were analyzed with and without nuclear flashlamp augmentation. The pulse shapes indicate that the deposition of nuclear energy is equally as effective as electrical energy deposition in producing laser pulse energy output. The amplification of the E-beam pumped CF3I was measured at pressures of several atmospheres. Preliminary data shows that, for a part of the iodine laser pulse, amplification of almost a factor of two is measured. This measurement indicates that the gain in an E-beam pumped CF3I is an order of magnitude greater than in the coaxial laser tube.

Russell, G. R.

1979-01-01

186

Solid-state lasers based on copolymers of methyl methacrylate and 2-hydroxyethyl acrylate doped with pyrromethene 567 dye  

NASA Astrophysics Data System (ADS)

Solid-state dye laser samples based on copolymers of methyl methacrylate (MMA) and 2-hydroxyethyl acrylate (HEA) doped with pyrromethene 567(PM567) were prepared. The highest slope efficiency 46.4% was obtained. With pump repetition rate of 10 Hz and intensity of 0.1 J/cm2, the output energy of the sample based on P (MMA: HEA 16:4) remained up to 82.10% of its initial value after approximate 100000 shots. To our knowledge, the achieved photostability is the best under the same condition so far. Compared with the sample based on the monopolymer, the slope efficiency and photostability of copolymer-based solid-state dye samples were both enhanced. The results indicate that the high laser performance using solid-state dye samples based on copolymers of MMA with HEA as solid hosts can be achieved.

Chen, D. Y.; Jiang, Y. G.; Fan, R. W.; Peng, H.; Xia, Y. Q.

2009-05-01

187

Solar-simulator-pumped atomic iodine laser kinetics  

Microsoft Academic Search

The literature contains broad ranges of disagreement in kinetic data for the atomic iodine laser. A kinetic model of a solar-simulator-pumped iodine laser is used to select those kinetic data consistent with recent laser experiments at the Langley Research Center. Analysis of the solar-simulator-pumped laser experiments resulted in the following estimates of rate coefficients: for alkyl radical (n-C3F7) and atomic

H. W. Wilson; S. Raju; Y. J. Shiu

1983-01-01

188

Recycle Rate in a Pulsed, Optically Pumped Rubidium Laser  

SciTech Connect

A pulsed, optically pumped rubidium laser operating in analogy to the diode pumped alkali laser (DPAL) system at pump intensities as high as 750 kW/cm{sup 2} has been demonstrated with output energies of up to 13 {mu}J/pulse. Output energy is dramatically limited by spin-orbit relaxation rates under these high intensity pump conditions. More than 250 photons are available for every rubidium atom in the pumped volume, requiring a high number of cycles per atom during the 2-8 ns duration of the pump pulse. At 550 Torr of ethane, the spin-orbit relaxation rate is too slow to effectively utilize all the incident pump photons. Indeed, a linear dependence of output energy on pump pulse duration for fixed pump energy is demonstrated.

Miller, Wooddy S.; Sulham, Clifford V.; Holtgrave, Jeremy C.; Perram, Glen P. [Department of Engineering Physics, Air Force Institute of Technology, 2950 Hobson Way, Wright-Patterson Air Force Base, Ohio 45433-7765 (United States)

2010-10-08

189

Biological research by optically pumped far infrared lasers  

NASA Astrophysics Data System (ADS)

The FIR breeding for paddy rice, black bean and wheat, the chlorophyll mutation of paddy rice induced by optically pumped FIR laser, etc., are presented. The results of SDS electrophoresis analysis of soluble proteins of Drosophita melanrgaster irradiated by optically pumped FIR laser are described and discussed.

Zhengyu, Mi

1989-05-01

190

Experiments on gas-phase optically pumped infrared lasers  

Microsoft Academic Search

Population inversions in small gas-phase molecules are produced by optical pumping of vibrational overtone transitions. Efficient frequency down conversion of the pump radiation is obtained by lasing on the inverted transitions. The performance of the lasers is governed by kinetic relaxation and energy exchange processes. The effect of these processes on the ultimate scalability of this class of laser will

Harold C. Miller; Gordon D. Hager

1995-01-01

191

The nuclear pumped laser program at the University of Illinois  

NASA Astrophysics Data System (ADS)

Nuclear pumped lasers (NPLs) have been under study at the University of Illinois for a number of years. This paper describes one recently completed, and two on-going studies related to NPLs. These include an experimental and theoretical investigation of the atomic iodine laser excited with a nuclear pumped XeBr* flashlamp; an experimental investigation of the nuclear pumped Ne (585 nm) laser; and experimental measurements on spatial pumping power uniformity in NPL cavities. Progress and results in each of these three studies are reviewed.

Miley, G. H.; Williams, W. H.; Shaban, Y.; Petra, M.

192

Grating formation in bi-layered DNA-complex devices: application to thin-film tunable dye lasers  

NASA Astrophysics Data System (ADS)

Interaction of some organic dyes with DNA induces fluorescence enhancement through intercalation or groove binding, stimulating the development of compact tunable thin-film dye lasers. We have demonstrated amplified spontaneous emission (ASE), laser emission and its tuning via distributed feedback (DFB) with a dynamic grating formed in DNA-surfactant complexes doped with cyanine or hemicyanine dyes. The formation of semi-persistent (or quasi-dynamic) grating is more preferable in order to realize stable and easily tunable laser sources, so we fabricated bi-layered devices composed of a DNA-CTMA layer doped with pyridine 1 (Py1) and an PMMA layer including an azo dye, Disperse Red 1 (DR1). Under simultaneous excitation of the azo layer with interfering two beams for grating formation and the emission layer with another beam as pumping, we observed laser emission from the device. The oscillation wavelength was controlled by varying the incident beam angles allowing the fast tuning suitable to applications. Furthermore, monolithic DNA device having two functions of lasing and grating formation would be more promising. DNA-CTMA complex had been considered to be a poor matrix for grating inscription, but we found that doping of an azo-carbazole compound made it possible to inscribe gratings with relatively high diffraction efficiency and with fast response which could be applicable to monolithic tunable laser system.

Kawabe, Yutaka; Chida, Toshifumi; Matsuoka, Toshinori; Fukuzawa, Kodai; Tada, Kazuhiro

2013-10-01

193

Spectroscopy and laser action of the "red perylimide dye" in various solvents  

NASA Astrophysics Data System (ADS)

Optical properties of the red perylimide laser dye in various solvents are studied. The absorption spectrum exhibits two main bands, in the ranges 480-600 and 400-460 nm, due to the S 0-S 1 and S 0-S 2 transition. The fluorescence spectrum is a mirror image of the S 0-S 1 absorption (shift of ˜ 30-50 nm). The Stokes shift increases with solvent polarity. Such dye-solvent interactions are compared to theoretical predictions. The fluorescence quantum yields approaches unity in all the solvents studied. Laser tunability around 30 nm was obtained each time, covering the spectral range 580-640 nm. This interval is important for medical applications in photodynamic therapy and fluorescence diagnostics. The laser threshold energy varied from 0.35 mJ/pulse in cyclohexane to 1.87 mJ/pulse in methanol, and the slope efficiency from about 6.6% in methanol to 14% in xylenes. The laser output was stable for several hours of operation under an average pump energy of about 20 mJ/pulse at 1 Hz repetition rate, without flow.

Gvishi, R.; Reisfeld, R.; Burshtein, Z.

1993-10-01

194

Experiments and modeling of optically-pumped hydrogen halide lasers  

Microsoft Academic Search

Experiments on an optically-pumped hydrogen fluoride laser are discussed. Rotation-vibration transitions are pumped on overtone bands and lasing is observed on delta v = I transitions at wavelengths near 2.7 microns. Kinetic modeling of short-pulsed optically-pumped hydrogen halide lasers has been carried out. The model utilizes sealing laws to obtain rate constants describing the energy transfer reactions. A truncated version

Nicholas P. Machara; Harold C. Miller; Dan T. Radzykewycz Jr.; Gordon D. Hager

1993-01-01

195

An experimental optimization study for concentration and laser power effects in the fullerene-C 60 and azo dye doped guest-host liquid crystal systems  

NASA Astrophysics Data System (ADS)

The current-voltage characteristics of a famous guest-host liquid crystal system have been investigated under dark and laser illumination conditions. Dependency of current modulation with respect to concentration and laser power gives some optimization possibilities and estimations on the reorientation mechanisms of the liquid crystals. The current-voltage character of pure E7 is almost unchanged with laser pumping, while the fullerene and dye doping are enhancing effects in their individual and collective usage. The negative resistance effect was observed for some certain concentrations of the dye and C 60, and this peculiarity is shown to be switched with laser illumination. The mobility of the doped LC samples was calculated by transient current measurements and its dependency on the dye concentration and the laser power was investigated. It is evaluated that the effect of methyl red is a critical parameter in photoconductivity applications of liquid crystals.

Okutan, M.; Köysal, O.; San, S. E.; Yakuphanoglu, F.

2009-11-01

196

Low threshold solar-pumped iodine laser  

NASA Technical Reports Server (NTRS)

Solar-pumped lasing of i-C3F7I and n-C4F9I at lower solar concentrations (170 solar constants) and longer gain lengths than previous solar lasers is demonstrated, with potential application to the lasing needs of space. Two xenon arc solar simulators provide an AM0 spectrum over the 60-cm gain length, and output pulse energies of 70 mJ and an average power of 550 mW are achieved. Low pressure lasing times of 600 ms are reached, and the observed 0.074 percent slope efficiency could approach the 0.2 percent maximum theoretical efficiency. Due to less quenching of I(asterisk), n-C4F9I is found to be a superior lasant to i-C3F7I.

Deyoung, R. J.

1986-01-01

197

Astigmatically compensated cavities for CW dye lasers  

Microsoft Academic Search

An analysis is given of folded 3-mirror laser resonators with an internal cell set at Brewster's angle. A method is described to compensate the astigmatic distortions introduced by both the internal mirror and the cell. This compensation is achieved for a specific relation between cell thickness and folding angle. It allows the formation of a tight intracavity focus as required

H. Kogelnik; E. Ippen; A. Dienes; C. Shank

1972-01-01

198

Low threshold solar-pumped iodine laser  

SciTech Connect

Solar-pumped lasing of i-C/sub 3/F/sub 7/I and n-C/sub 4/F/sub 9/I has been achieved at very low threshold pumping powers (170 solar constants) using a long (60 cm) gain length box laser configuration. Two xenon arc solar simulators were used to provide an AMO spectrum over the 60 cm gain length. Maximum pulse energy of 73mJ and average power of 525 mW were achieved at 7.3kW optical input. A slope efficiency of 0.074 percent was measured, the maximum theoretical efficiency being 0.2 percent. Longer gain lengths allow reduced optical input concentration, thus making the solar trough collector feasible for space applications. n-C/sub 4/F/sub 9/I was found to have less quenching of I*, making it a superior lasant to i-C/sub 3/F/sub 7/I.

DeYoung, R.J.

1986-07-01

199

An optically-pumped multigas far-IR laser  

SciTech Connect

In the present experiment, CH/sub 3/OH, CH/sub 3/Br, and CH/sub 3/I were simultaneously introduced into a far-IR, optically pumped laser cavity. The adjustment of the partial pressures of the three gases and the tuning of the appropriate CO/sub 2/ laser pump line yielded laser operation for each of them which is assessed to be as efficient as that obtainable from the gases in isolation.

Prasad, J.; Rao, D.N.; Prasad, P.N.

1983-01-01

200

Chemical oxygen-iodine laser with cryosorption vacuum pump  

NASA Astrophysics Data System (ADS)

In a chemical oxygen-iodine laser (COIL), chemically prepared, gaseous gain medium at 3-10 Torr pressure is drawn through the laser cavity by vacuum suction. Multiple-stage vacuum pumps such as Roots blowers or steam ejectors are typically used to receive and compress the gas flowing from the laser and exhaust it to the atmosphere. The size and weight of such vacuum pumps present a significant challenge to engineering and packaging a transportable COIL system.

Vetrovec, John

2000-05-01

201

High power CW iodine laser pumped by solar simulator  

NASA Technical Reports Server (NTRS)

An iodine photodissociation laser was pumped by a long Ar arc as the solar simulator to produce a 10-W CW output. Continuous lasing for 1 h was achieved with a flow of the laser material n-C3F7I. The 10-W CW output is the highest produced to date and establishes the feasibility of developing a solar-pumped laser for space power transmission.

Lee, Ja H.; Lee, Min H.; Weaver, Willard R.

1987-01-01

202

High-power CW tunable solid state dye lasers: from the visible to UV  

NASA Astrophysics Data System (ADS)

We describe a high power CW solid-state dye laser setup. With perylene orange in PMMA as gain medium an output power up to 800 mW at 576 nm and a tuning range between 565 and 595 nm is reached. The laser output shows good long time power stability. The durability can be adjusted by variation of the pump power. A feedback loop controls the laser output. At a setpoint of e.g. 100 mW, the laser output can be provided for more than eight hours with a low noise level (RMS < 10%). The spectral width of the laser emission is less than 3 GHz and can be tuned over more than 30 nm. A circular mode-profile is achieved with M2 < 1.4 [1]. Via intra-cavity second harmonic generation more than 1 mW of 290 nm UV-radiation is achieved. As nonlinear element a 7 mm BBO (Beta-Barium Borate) crystal is used. The UV laser radiation can be tuned over 10 nm. The theoretical limit of UV output is estimated to 3.5 mW. To our knowledge we present the first tunable CW polymer UV laser. While the output stability at the fundamental wavelength is reasonably good, in the UV region a significant enhancement of the noise level is observed. In addition to this the long time stability is reduced to few minutes. The limitation is mainly given by the photo-decomposition of the organic dye molecules.

Bornemann, R.; Thiel, E.; Haring Bolívar, P.

2012-06-01

203

The role of the molecular dynamics in the local intensity instabilities of large aperture dye lasers  

E-print Network

lasers I. Leyvaa) and J. M. Guerra Departamento de O´ ptica, Facultad de Ciencias Fi´sicas Universidad fluctuations of large aperture dye lasers, and find dependencies on solvent viscosity and active molecular size dye lasers are used in a great deal of practical applications, from isotope enrichment to photody

Rey Juan Carlos, Universidad

204

The role of the solvent viscosity on the spatiotemporal instabilities of large aperture dye lasers  

E-print Network

The role of the solvent viscosity on the spatiotemporal instabilities of large aperture dye lasers for publication 27 May 1998 Local intensity fluctuations in a large aperture dye laser have been measured behavior as the molecular polarization orientation driven by the laser field. © 1998 American Institute

Rey Juan Carlos, Universidad

205

Dye-mixture laser tunable in three primary color regions with a linear variable filter.  

PubMed

The tuning characteristics of a Coumarine 460-Disodium Fluorescein-Rhodamine 640 dye-mixture laser in the blue, green, and yellow-orange regions are reported. A linear variable filter was inserted into the laser cavity as a tuning element. The tunable range was 439-485 nm in the blue region, 509-531 nm in the green region, and 592-601 nm in the yellow-orange region. Comparison of the characteristics of the one-wavelength tuning output with those of simultaneous broadband outputs in the three color regions showed that energy transfer was an important mechanism for the oscillations, especially in the longer-wavelength region, which was farthest away from a pumping wavelength. PMID:20963135

Saito, Y; Shimodaira, K; Nomura, A; Kano, T

1995-01-20

206

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

SciTech Connect

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.

Abdel-Kareem, O. [Conservation Department, Faculty of Archaeology, Cairo University (Egypt); Eltokhy, A.; Harith, M. A. [National Institute of Laser Enhanced Science, Cairo University (Egypt)

2011-09-22

207

XeCl laser pumped iodine laser using t-C4F9I  

NASA Technical Reports Server (NTRS)

An iodine photodissociation laser using t-C4F9I as the active material was pumped by an XeCl laser. An iodine laser output energy of 3 mJ with pulse duration of 25 ns was obtained when the pumping pulse energy was 80 mJ, the iodide pressure was 70 torr, and the reflectance of the output mirror was 85 percent. The high pumping efficiency and low threshold pump power achieved in this experiment are attributable to the high absorption cross section at the pump laser wavelength (308 nm) of the iodide used.

Hwang, In Heon; Han, Kwang S.

1989-01-01

208

XeCl laser pumped iodine laser using t-C4F9I  

NASA Technical Reports Server (NTRS)

An iodine photodissociation laser using t-C4F9I as the active material was pumped by a XeCl laser. An iodine laser output energy of 3 mJ with pulse duration of 25 ns was obtained when the pumping pulse energy was 80 mJ, the iodine pressure was 70 torr, and the reflectance of the output mirror was 85 percent. The high pumping efficiency and low threshold pump power achieved in this experiment are attributable to the high absorption cross section at the pump laser wavelength (308 nm) of the iodide used.

Hwang, In Heon; Han, Kwang S.; Lee, Ja H.

1989-01-01

209

Treatment of hemangiomas with 595 nm pulsed dye laser dermobeam.  

PubMed

The third generation dye lasers are pulsed dye lasers with a wavelength of 595 nm. Hemangiomas are the most common benign tumor in infancy, and ulceration is their most frequent complication. We used a 595 nm, Dermobeam 2000 laser (from Deka MELA Calenzano, Italy), using a dynamic skin cooling system (Spray) as the cooling method. The diameter of the spots was 7 mm, the energy density (fluence J/cm2) from 4 to 8 J/cm2. The emission modality (repetition rate) was repeated at 0.5 Hz. We initially chose a long pulse duration of 30 msec, but in the majority of cases it was 0.5 msec. The SmartSpray Cooling system parameters were : freezing, flood, duration, and advance. The spray length was from 60%. The delay (advance or anticipation) was 10 msec. The anesthetic effect limited the need for additional topical, local or general anesthetic. In a prospective study, we treated 16 patients with 22 cutaneous hemangiomas from July 2000 to February 2002 (over a 19 month period), with a mean follow up of 22.44 months (10 to 42 months). Our purpose was to review the therapeutic response of ulcerated hemangioma to the third generation pulsed dye laser. The female/male sex ratio was approximately 3 :1 (12 girls, and 4 boys). Patients were aged from 1 to 15 months, for a mean of 4.9 months. We tried to evaluate the therapeutic response of ulcerated hemangiomas to 595 nm wavelength pulsed dye laser. We observed no adverse effects; however 2 failures due to pain were recorded from ulcerated hemangiomas as the severity of the subcutaneous component of the mixed hemangiomas remained unchanged. These 2 cases showed proliferation of the subcutaneous component, and required general corticosteroids. We examined the children about 10 to 15 days after the first treatment, and evaluated the residual pain. The treatment could be continued while the pain level is low (1 session in most cases), and until the ulceration heals (after 4 sessions). Laser therapy was always effective on severe bleeding, but recurrences were frequent and it was necessary to treat hemangiomas until the end of the cicatrisation. Laser therapy is indicated for hemangiomas only in rare instances : due to the refractory ulceration failing to heal after 2 weeks of specialized dressing, aesthetic risk due to localization (such as philtrum, columella, or nasal margin). It is also possible to treat residual telangiectasia. No uniformly effective treatment modality was found. PMID:12695128

Michel, Jean-Loïc

2003-01-01

210

DPSS Laser Beam Quality Optimization Through Pump Current Tuning  

SciTech Connect

The goal of this study is to demonstrate how a DPSS laser beam's quality parameters can be simultaneously optimized through pump current tuning. Two DPSS lasers of the same make and model were used where the laser diode pump current was first varied to ascertain the lowest RMS noise region. The lowest noise was found to be 0.13% in this region and the best M{sup 2} value of 1.0 and highest laser output power were simultaneously attained at the same current point. The laser manufacturer reported a M{sup 2} value of 1.3 and RMS noise value of .14% for these lasers. This study therefore demonstrates that pump current tuning a DPSS laser can simultaneously optimize RMS Noise, Power and M{sup 2} values. Future studies will strive to broaden the scope of the beam quality parameters impacted by current tuning.

Omohundro, Rob; /Newport Spectra-Physics, Santa Clara; Callen, Alice; /SLAC; Sukuta, Sydney; /San Jose City Coll.

2012-03-30

211

Method and apparatus for efficient operation of optically pumped laser  

NASA Technical Reports Server (NTRS)

An optically pumped single mode laser, e.g., Nd:YAG crystal (20) with planoconcave mirrors is increased in efficiency by an order of magnitude to about 8% by optics (25, 27) for focusing the high power multimode output of laser diode arrays (21, 22) into the mode volume (20') of the laser medium (20). A plurality of these optically pumped single mode lasers (1-4) may be cascaded in a ring with dichroic mirrors (M.sub.1 -M.sub.4) at the corners for coupling in the laser diode arrays, each having its own means for spatially tailoring its beam to concentrate pump distribution inside the lasing mode volume of the medium. An InGaAlAs pump diode (30) with its wavelength the same as the lasing medium makes the ring unidirectional.

Sipes, Jr., Donald L. (Inventor)

1987-01-01

212

Tunable narrow linewidth laser output from PM567 doped nematic liquid crystal under holographic pumping  

NASA Astrophysics Data System (ADS)

LC cell injected the mixture of dye pyrromethene 567 (PM567) and nematic liquid crystal (NLC) by capillary action was prepared. Holographic pumping with a Nd:YAG laser (532 nm, 1 Hz, 10 ns) to form gain distributed feedback in the cell, tunable laser output from the cell was investigated. Through changing the intersection angles of the two coherent light beams from 46° to 50°, the tuning range we obtained is about 37 nm (550-587 nm). Additionally, the FWHM of the laser under such experimental setup was less than 0.1 nm even without the resonant cavity, and the threshold of the laser was about 26 ?J, which was very low as we known.

Chen, D. Y.; Fan, Y. K.; Fan, R. W.; Xia, Y. Q.

2011-12-01

213

Direct solar pumping of semiconductor lasers: A feasibility study  

NASA Technical Reports Server (NTRS)

This report describes results of NASA Grant NAG-1-1148, entitled Direct Solar Pumping of Semiconductor Lasers: A Feasibility Study. The goals of this study were to provide a preliminary assessment of the feasibility of pumping semiconductor lasers in space with directly focused sunlight and to identify semiconductor laser structures expected to operate at the lowest possible focusing intensities. It should be emphasized that the structures under consideration would provide direct optical-to-optical conversion of sunlight into laser light in a single crystal, in contrast to a configuration consisting of a solar cell or storage battery electrically pumping a current injection laser. With external modulation, such lasers could perhaps be efficient sources for intersatellite communications. We proposed specifically to develop a theoretical model of semiconductor quantum-well lasers photopumped by a broadband source, test it against existing experimental data where possible, and apply it to estimating solar pumping requirements and identifying optimum structures for operation at low pump intensities. These tasks have been accomplished, as described in this report of our completed project. The report is organized as follows: Some general considerations relevant to the solar-pumped semiconductor laser problem are discussed in Section 2, and the types of structures chosen for specific investigation are described. The details of the laser model we developed for this work are then outlined in Section 3. In Section 4, results of our study are presented, including designs for optimum lattice-matched and strained-layer solar-pumped quantum-well lasers and threshold pumping estimates for these structures. It was hoped at the outset of this work that structures could be identified which could be expected to operate continuously at solar photoexcitation intensities of several thousand suns, and this indeed turned out to be the case as described in this section. Our project is summarized in Section 5, and information on publications resulting from this work is provided in Section 6.

Anderson, Neal G.

1992-01-01

214

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

NASA Astrophysics Data System (ADS)

The development and application of optical parametric (OP) systems with pulsed dye amplifiers producing single frequency mode (SFM), narrow linewidth, and tunable laser radiation for high-spectral-resolution laser diagnostics is described. An optical parametric generator (OPG) was developed, consisting of a pair of counter-rotating ? barium borate (?-BBO) crystals pumped by third-harmonic output of an injection-seeded Nd:YAG laser. The OPG crystals themselves are injection-seeded using a continuous wave (cw) distributed feedback (DFB) diode laser or external cavity diode laser (ECDL) at idler wavelength. The OPG is converted for some applications into an optical parametric oscillator (OPO) by incorporating a feedback cavity. The signal output from the OP system is amplified using pulsed dye amplifiers. The PDAs are pumped either by second-harmonic or third-harmonic output of the Nd:YAG laser depending on the OP output wavelength and the dye solution used in PDAs. The linewidth of the laser beam produced using OP/PDA systems is 200 MHz and the spatial beam profile is nearly Gaussian. Initial application of OP/PDA system included two-photon laser induced fluorescence (LIF) of atomic oxygen in counter-flow flames, dual pump coherent anti-Stokes Raman spectroscopy (CARS) for N2 and CO2, and nitric oxide (NO) planar laser induced fluorescence (PLIF) in compressible flowfield. A two-photon pump polarization spectroscopy probe (TPP-PSP) laser system has also been developed using two SFM OPG/PDA systems for the detection of atomic hydrogen (H-atom) in flames. In TPP-PSP, a 243-nm pump beam excites the 1S-2S two photon transition and the excited atoms in 2S level are probed by polarization spectroscopy between n=2 and n=3 manifolds using a circularly polarized 656-nm pump and a linearly polarized 656-nm probe laser beam. Using the TPP-PSP scheme, atomic hydrogen was detected at concentrations as low as 11 ppm. The use of injection-seeded OPG/PDAs as SFM sources for the pump and probe beams allows accurate measurement of signal intensities and spectral lineshapes. A detailed investigation of the effect of 243-nm and 656-nm pump beam energies on the different transitions of atomic hydrogen was performed. TPP-PSP lineshapes for high energy 243-nm and 656-nm pump beams showed significant broadening when compared with lineshapes for lower energy 243-nm and 656-nm pump beams. A continuous shifting of the center of n=2-n=3 transition was also observed with increasing 243-nm pump beam energy. Sub-Doppler H-atom lineshapes were also investigated and exhibited significant narrowing. The effect of varying collisional environments on the TPP-PSP signal from atomic hydrogen was investigated by performing measurements in near-adiabatic hydrogen-air flames. The results of these measurements are very encouraging for quantitative measurements of atomic hydrogen in flames.

Bhuiyan, Aizaz Hossain

215

Assignment of the /Li-7/2 optically pumped laser transitions pumped by Ar/+/ and Kr/+/ laser lines  

NASA Technical Reports Server (NTRS)

Welling and Wellegehausen (1977) have reported a list of Na2 and Li2 lines (belonging to B-X and A-X systems) which lase when vapors of these dimers are pumped with an Ar(+) or Kr(+) laser. A description is presented of a fluorescence study of the A-X system of the (Li-7)2 molecule excited by a Kr(+) laser (6471 A). The optically pumped laser lines are identified as P and R doublets in two different fluorescence series. The conditions which favor lasing action of these lines are pointed out. All but one of the known optically pumped laser lines of (Li-7)2 along with their assignments are presented in a table. For each pumping line, several additional wavelengths are listed which satisfy the condition for laser oscillations and which might well lase well under slightly improved conditions.

Verma, K. K.; Stwalley, W. C.; Zemke, W. T.

1981-01-01

216

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

DOEpatents

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.

Hammond, P.R.

1983-12-29

217

LASERS AND AMPLIFIERS: Peculiarities of pumping of copper vapour and copper bromide vapour lasers  

NASA Astrophysics Data System (ADS)

Lasing and peculiarities of pumping of a copper vapour laser with a commercially produced 'Crystal' LT-40Cu active element and of a CuBr laser with a large-volume experimental active element are studied experimentally. It is shown that the efficiency of lasers with an average radiation power up to 50 W relative to the energy supplied to the active medium during useful pumping achieves 4%. It is found that the stage of useful pumping of the central part of the laser tube is preceded by a partial breakdown of the discharge gap and the charging of parasitic capacitances. A distinguishing feature of the pumping of a CuBr laser as compared to the Cu laser is that the inductance of the leads from the pump oscillator to the active element and the inductance of the pump oscillator can be increased, while the average radiation power remains unchanged.

Evtushenko, Gennadii S.; Kostyrya, I. D.; Sukhanov, V. B.; Tarasenko, Viktor F.; Shiyanov, D. V.

2001-08-01

218

Advancement of High Power Laser Diodes for Pumping 2-micron Solid State Lasers  

Microsoft Academic Search

The reliability and lifetime demanded by space- based applications of 2-micron solid state lasers are beyond the capability of currently available laser diode arrays. This paper provides the status of an ongoing technology advancement effort toward long-lifetime high power laser diode arrays suitable for pumping Thulium and Holmium based solid state lasers. I. INTRODUCTION Laser diode array is a critical

Farzin Amzajerdian; Byron Meadows; Michael Kavaya; Upendra Singh; Nathaniel Baker; Vikas Sudesh

219

Overview and future direction for blackbody solar-pumped lasers  

NASA Technical Reports Server (NTRS)

A review of solar-pumped blackbody lasers is given which addresses their present status and suggests future research directions. The blackbody laser concept is one system proposed to scale to multimegawatt power levels for space-to-space power transmissions for such applications as onboard spacecraft electrical or propulsion needs. Among the critical technical issues are the scalability to high powers and the laser wavelength which impacts the transmission optics size as well as the laser-to-electric converter at the receiver. Because present blackbody solar-pumped lasers will have laser wavelengths longer than 4 microns, simple photovoltaic converters cannot be used, and transmission optics will be large. Thus, future blackbody laser systems should emphasize near visible laser wavelengths.

Deyoung, R. J.

1988-01-01

220

Optical phase conjugation by degenerate four-wave mixing in basic green 1 dye-doped gelatin film using He–Ne laser  

Microsoft Academic Search

Optical phase conjugation in gelatin film doped with basic green 1 has been measured using CW laser radiation (?=632.8nm) generated by He–Ne laser of total power 35mW. The degenerate four-wave mixing (DFWM) experiment allowed for measurement of phase conjugate reflectivity as a function of dye concentration, backward beam intensity, forward beam intensity, probe beam intensity, mean pumping beam intensity and

Qusay Mohammed Ali; P. K. Palanisamy

2007-01-01

221

Fiber-DFB laser array pumped with a single 1-W CW Yb-fiber laser  

Microsoft Academic Search

A 50-GHz grid fiber distributed feedback laser wavelength-division-multiplexing transmitter source is demonstrated pumped by a single continuous-wave Yb-fiber laser source at 977 nm. Up to 21 mW of output power is achieved per channel with maintenance of key operational parameters. The performance of this single Yb-fiber laser pump configuration is also compared with that of a semiconductor pump configuration which

L. B. Fu; R. Selvas; M. Ibsen; J. K. Sahu; J. N. Jang; S.-U. Alam; J. Nilsson; D. J. Richardson; D. N. Payne; C. Codemard; S. Goncharov; I. Zalevsky; A. B. Grudinin

2003-01-01

222

XeCl laser pumped iodine laser using tC4F9I  

Microsoft Academic Search

An iodine photodissociation laser using t-C4F9I as the active material was pumped by an XeCl laser. An iodine laser output energy of 3 mJ with pulse duration of 25 ns was obtained when the pumping pulse energy was 80 mJ, the iodide pressure was 70 torr, and the reflectance of the output mirror was 85 percent. The high pumping efficiency

In Heon Hwang; Kwang S. Han

1989-01-01

223

XeCl laser pumped iodine laser using tC4F9I  

Microsoft Academic Search

An iodine photodissociation laser using t-C4F9I as the active material was pumped by a XeCl laser. An iodine laser output energy of 3 mJ with pulse duration of 25 ns was obtained when the pumping pulse energy was 80 mJ, the iodine pressure was 70 torr, and the reflectance of the output mirror was 85 percent. The high pumping efficiency

In Heon Hwang; Kwang S. Han; Ja H. Lee

1989-01-01

224

Polarization properties of laser-diode-pumped micro-grained Nd:YAG ceramic lasers  

Microsoft Academic Search

Detailed polarization properties have been examined in laser-diode-pumped (LD-pumped) micro-grained ceramic Nd:YAG lasers in different microchip cavity configurations. Stable linearly-polarized single-frequency oscillations, whose polarization direction coincide with that of an LD pump light, were observed in an external cavity scheme. While, in the case of a thin-slice laser scheme with coated reflective ends, elliptically-polarized single-frequency operations took place in the

Kenju Otsuka; Takayuki Ohtomo

2008-01-01

225

Green HgCl-laser with wideband optical pumping  

NASA Astrophysics Data System (ADS)

A photodissociation laser using the B-X electron transition in mercury chloride (wavelengths, 558 and 559 nm) is reported. The laser employs wideband optical pumping of HgCl2 vapors by a thermal plasma emission. The laser pulse energy reaches 2.1 J with a duration of 7.6 microsec; the efficiency of the laser with respect to the stored energy is 0.1 percent.

Bazhulin, S. P.; Basov, N. G.; Bugrimov, S. N.; Zuyev, V. S.; Kamrukov, A. S.; Kashnikov, G. N.; Kozlov, N. P.; Ovchinnikov, P. A.; Opekan, A. G.; Orlov, V. K.

1987-04-01

226

A green mercury chloride laser with wideband optical pumping  

NASA Astrophysics Data System (ADS)

A photodissociation laser using the B-X electron transition in mercury chloride (wavelengths, 558 and 559 nm) is reported. The laser employs wideband optical pumping of HgCl2 vapors by a thermal plasma emission. The laser pulse energy reaches 2.1 J with a duration of 7.6 microsec; the efficiency of the laser with respect to the stored energy is 0.1 percent.

Bazhulin, S. P.; Basov, N. G.; Bugrimov, S. N.; Zuev, V. S.; Kamrukov, A. S.

1986-06-01

227

Chemically pumped iodine laser as a fusion driver  

SciTech Connect

The recently demonstrated chemically pumped iodine laser is evaluated for fusion requirements. Efficiencies greater than 8% and long energy storage times are predicted, with high repetition rates and elimination of pulsed power supplies.

Busch, G.E.

1980-01-01

228

AlGaAs diode pumped tunable chromium lasers  

DOEpatents

An all-solid-state laser system is disclosed wherein the laser is pumped in the longwave wing of the pump absorption band. By utilizing a laser material that will accept unusually high dopant concentrations without deleterious effects on the crystal lattice one is able to compensate for the decreased cross section in the wing of the absorption band, and the number of pump sources which can be used with such a material increases correspondingly. In a particular embodiment a chromium doped colquiriite-structure crystal such as Cr:LiSrAlF.sub.6 is the laser material. The invention avoids the problems associated with using AlGaInP diodes by doping the Cr:LiSrAlF.sub.6 heavily to enable efficient pumping in the longwave wing of the absorption band with more practical AlGaAs diodes.

Krupke, William F. (Pleasanton, CA); Payne, Stephen A. (Castro Valley, CA)

1992-01-01

229

A solar simulator-pumped atomic iodine laser  

NASA Technical Reports Server (NTRS)

An atomic iodine laser, a candidate for the direct solar-pumped gas laser, was excited with a 4-kW beam from a xenon arc solar simulator. Continuous lasing at 1.315 micron for over 10 ms was obtained for static filling of n-C3F7I vapor. By momentarily flowing the lasant, a 30-Hz pulsed output was obtained for about 200 ms. The peak laser power observed was 4 W for which the system efficiency reached 0.1%. These results indicate that direct solar pumping of a gas laser for power conversion in space is indeed feasible.

Lee, J. H.; Weaver, W. R.

1981-01-01

230

Multiple pulses EUV laser pumping: ASE, seeded operations, and applications  

NASA Astrophysics Data System (ADS)

We present in this paper a laser-driven coherent EUV beamline resulting from the combination of a versatile high-order laser harmonic generator with a robust plasma-based EUV laser amplifier. Both devices can be used separetely or in synergy. Seeding of the plasma amplifier by a high-order harmonic beam leads to a strong improvement of the EUV laser beam divergence and uniformity. Moreover the system can be turned easily into a IR pump-XUV probe setup for plasma opacity probing. The possibility to generate two separate harmonic sources from the same gas cell offers the opportunity to explore EUV pump-EUV probe experiments.

Ros, D.; Kazamias, S.; Cassou, K.; Pittman, M.; Guilbaud, O.; Daboussi, S.; Delmas, O.; Demailly, J.; Neveu, O.; Mestrallain, A.; Sall, D.; Li, L.; Zeitoun, P.

2013-10-01

231

-mode Nd:YAG laser with annular pumping  

NASA Astrophysics Data System (ADS)

We demonstrated a radially polarized, LG01-mode Nd:YAG laser by applying annular-shaped pump light. The annular profile of the pump light was originated from the mode conversion inside a conventional multimode fiber under off-focus coupling condition. This laser gave a maximum output power of 1.2 W at 1,064 nm with a slope efficiency of 28.3 %.

Fang, Zhiqiang; Xia, Kegui; Yao, Yao; Li, Jianlang

2014-10-01

232

Thermal effects of pulsed pumping in semiconductor disk lasers  

NASA Astrophysics Data System (ADS)

It has been demonstrated experimentally that pulsed pumping can significantly improve the thermal management in an optically-pumped semiconductor disk laser, and the output power of semiconductor disk lasers under pulsed pumping can be upgraded to times of those under continuous pumping. This paper presents numerical analysis of the thermal effects of pulsed pumping in semiconductor disk lasers, so to theoretically disclose the details of the thermal processes of pulsed pumping. In the simulation, the parabolic heat conduction equation, which is widely employed to describe the transient thermal transfer processes, is solved under cylindrical coordinates by the use of the finite element method, a periodic pump pulses train is assumed, and the maximum temperature rise in the multiple quantum wells active region is focused. The influences of the duty cycle, the repetition rate, and the pulse width of the pump pulses on the maximum temperature rise are investigated, and the results are compared with the case of continuous-wave pumping. Some simulation results are compared with reported data, and the theoretical results are in good agreement with the experiments.

Zhang, Peng; Dai, Teli; Liang, Yiping; Fan, Siqiang; Zhang, Yu

2012-11-01

233

Feasibility of supersonic diode pumped alkali lasers: Model calculations  

SciTech Connect

The feasibility of supersonic operation of diode pumped alkali lasers (DPALs) is studied for Cs and K atoms applying model calculations, based on a semi-analytical model previously used for studying static and subsonic flow DPALs. The operation of supersonic lasers is compared with that measured and modeled in subsonic lasers. The maximum power of supersonic Cs and K lasers is found to be higher than that of subsonic lasers with the same resonator and alkali density at the laser inlet by 25% and 70%, respectively. These results indicate that for scaling-up the power of DPALs, supersonic expansion should be considered.

Barmashenko, B. D.; Rosenwaks, S. [Department of Physics, Ben-Gurion University of the Negev, Beer-Sheva 84105 (Israel)] [Department of Physics, Ben-Gurion University of the Negev, Beer-Sheva 84105 (Israel)

2013-04-08

234

Direction controllable linearly polarized laser from a dye-doped cholesteric liquid crystal  

E-print Network

Direction controllable linearly polarized laser from a dye-doped cholesteric liquid crystal Ying demonstrate a direction controllable linearly polarized laser from a dye-doped cholesteric liquid crystal (CLC codes: (230.3720) Liquid crystal devices; (160, 3710) Materials References and links 1. V. I. Kopp, Z. Q

Wu, Shin-Tson

235

Direction controllable linearly polarized laser from a dye-doped cholesteric liquid crystal  

E-print Network

Direction controllable linearly polarized laser from a dye-doped cholesteric liquid crystal Ying demonstrate a direction controllable linearly polarized laser from a dye-doped cholesteric liquid crystal (CLC codes: (230.3720) Liquid-crystal devices, (160, 3710) Materials References and links 1. V. I. Kopp, Z. Q

Wu, Shin-Tson

236

Resonantly pumped high efficiency Ho:YAG laser.  

PubMed

High-efficient CW and Q-switched Ho:YAG lasers resonantly dual-end-pumped by two diode-pumped Tm:YLF lasers at 1908 nm were investigated. A maximum slope efficiency of 74.8% in CW operation as well as a maximum output power of 58.7 W at 83.2 W incident pump power was achieved, which corresponded to an optical-to-optical conversion efficiency of 70.6%. The maximum pulse energy of 2.94 mJ was achieved, with a 31 ns FWHM pulse width and a peak power of approximately 94.7 kW. PMID:23207298

Shen, Ying-Jie; Yao, Bao-Quan; Duan, Xiao-Ming; Dai, Tong-Yu; Ju, You-Lun; Wang, Yue-Zhu

2012-11-20

237

New stable tunable solid-state dye laser in the red  

NASA Astrophysics Data System (ADS)

A red perylene derivative was impregnated into a composite silica-gel glass, and characterized as a dye laser material. The absorption spectrum in the range 480 - 600 nm belongs to the S0 - S1 electronic transition, with a structure reflecting the perylene skeletal vibrations, of typical energy 1100 - 1200 cm-1. An additional peak between 400 and 460 nm belongs to the S0 - S2 transition. The fluorescence exhibits a mirror image relative to the S0 - S1 absorption, with a Stokes shift of about 40 nm for the 0 - 0 transition. Laser tunability was obtained in the range 605 - 630 nm using a frequency-doubled Nd:YAG laser for pumping ((lambda) equals 532 nm). This wavelength range is important for medical applications, such as photodynamic therapy of some cancer tumors. Maximum laser efficiency of approximately 2.5% was obtained at 617 nm. Maximum output was approximately 0.36 mJ/pulse at a repetition rate of 10 Hz. Minimum laser threshold obtained was 0.45 mJ/pulse. The medium losses are attributed to an excited-state singlet-singlet absorption, with an upper limit cross-section of approximately 2.5 X 10-16 cm2. The laser output was stable over more than approximately 500,000 pulses, under excitation with the green line of a copper vapor laser (510 nm), of energy density approximately 40 mJ/cm2 per pulse. Good prospects exist for a considerable enhancement in laser output efficiency.

Gvishi, Raz; Reisfeld, Renata; Burshtein, Zeev; Miron, Eli

1993-08-01

238

Solar-pumped photodissociation iodine laser@f|  

Microsoft Academic Search

The scientific feasibility of a solar-pumped iodine photodissociation laser for space applications is under investigation. Recently, a 2-watt CW output for more than one hour was achieved using n-C3F7I vapor as the laser material and a vortex-stabilized argon arc as the light source.

J. H. Lee; W. R. Weaver; D. H. Humes; M. D. Williams; M. H. Lee

1986-01-01

239

Optimization of laser fibers for high pump light absorption  

NASA Astrophysics Data System (ADS)

For the implementation of novel fiber laser concepts, such as extra-large mode area (X-LMA) fiber lasers or multi-core fiber lasers alternative manufacturing processes for highly-doped silica glasses and the laser fibers fabricated from it are required. For efficient laser operation a high absorption of pump power in the active fiber core is a necessary condition. To increase the pump light absorption the fiber development aimed at the preparation of laser-active and adapted passive single-large core fibers up to multi-core structures with 7 large cores showing broken circular fiber symmetry. The optimization of the optical fibers which will be shown in detail is based on the combination of several innovative manufacturing methods such as the powder sintering technology (REPUSIL), the preform preparation by stack-and-draw technique and the fiber drawing process. The described procedure is particularly suitable to produce multifilament glass preforms resp. laser fibers with large cores in which the radial and lateral indices of refraction can be adjusted homogeneously and reproducibly. Due to the realized increase of the laser-active core volume in these fibers the pump light absorption could be considerably increased and the resulting shorter fiber length allows the use of fibers with a moderate attenuation. The results concerning the characterization of materials science and the optical aspects e. g. the dopant concentration distributions and related refractive index profiles as well attenuation and pump absorption spectra will be presented.

Bierlich, Jörg; Kobelke, Jens; Jetschke, Sylvia; Grimm, Stephan; Unger, Sonja; Schuster, Kay

2014-03-01

240

Blackbody-Pumped CO2-N2 Transfer Laser.  

National Technical Information Service (NTIS)

A compact blackbody-pumped CO2-N2 transfer laser was constructed and the significant operating parameters were investigated. Lasing was achieved at 10.6 microns by passing preheated N2 through a 1.5-mm-diameter nozzle to a laser cavity where the N2 was mi...

R. J. Deyoung, N. S. Higdon

1984-01-01

241

REVIEW: Chemically pumped oxygen---iodine laser  

Microsoft Academic Search

A review is given of the principles of operation of the oxygen---iodine laser. Various types of chemical generators of singlet oxygen, which are key components in oxygen---iodine lasers, are considered. Experimental investigations of cw and pulsed oxygen---iodine lasers are described. The state-of-the-art theoretical investigations and potential applications of oxygen---iodine lasers are discussed.

Nikolai N. Yuryshev

1996-01-01

242

Photovoltaic converters for solar-pumped lasers  

NASA Technical Reports Server (NTRS)

The authors describe a mathematical parametric study of converters used to convert laser radiation to electricity for space-based laser power systems. Two different lasers, the 1.06-micron Nd laser and the 1.315-micron iodine laser, are used in the vertical junction converter. The calculated efficiency is 50 percent for a 100-junction Si photovoltaic converter when used with a Nd laser. The calculated efficiency for a 1000-junction Ga(0.53)In(0.47)As photovoltaic converter is 43 percent when used with an iodine laser.

Walker, Gilbert H.; Heinbockel, John H.

1988-01-01

243

Flashlamp-pumped iodine laser with an optically thick medium  

SciTech Connect

A procedure is described for numerical calculations of the temporal and radial dependences of the laser radiation power and energy and also of the refractive index for free-oscillation and inversion-storage conditions in the case of a cylindrically symmetric pump source positioned directly in the gaseous active medium. Some results of these calculations as applied to a CF/sub 3/I iodine photodissociation laser are presented. An analysis is made of the dependences of the laser characteristics on the active gas pressure, degree of dilution, flashlamp radius, resonator loss factor, and pump pulse profile and duration.

Vinokurov, G.N.; Zalesskii, V.Y.; Krepostnov, P.I.

1980-05-01

244

Compact VCSEL pumped Q-switched Nd:YAG lasers  

NASA Astrophysics Data System (ADS)

We have explored using 808nm Vertical Cavity Surface emitting laser (VCSEL) arrays for end-pumping of Nd:YAG lasers. A variety of laser designs were explored including a compact passively Q-switched lasers that produced a 22mJ pulse having a pulse width of <1.5ns, and an actively Q-switched laser that produced a 40mJ pulse having a 7 ns pulse width. The VCSEL pumped actively Q-switched laser was used as a source for sum frequency generation. Using a 2mm type II KTP and 3mm type I LBO, we generated greater than 5mJ at 355nm with a 21% THG conversion efficiency.

Cole, Brian; Hays, Alan; McIntosh, Chris; Nettleton, John; Goldberg, Lew

2012-03-01

245

Optical phase conjugation by degenerate four-wave mixing in basic green 1 dye-doped gelatin film using He Ne laser  

NASA Astrophysics Data System (ADS)

Optical phase conjugation in gelatin film doped with basic green 1 has been measured using CW laser radiation ( ?=632.8 nm) generated by He-Ne laser of total power 35 mW. The degenerate four-wave mixing (DFWM) experiment allowed for measurement of phase conjugate reflectivity as a function of dye concentration, backward beam intensity, forward beam intensity, probe beam intensity, mean pumping beam intensity and angle between the forward pumping beam and probe beam. For 1 mM concentration of basic green 1-doped gelatin film, 0.1% phase conjugate reflectivity has been observed.

Ali, Qusay Mohammed; Palanisamy, P. K.

2007-09-01

246

Experimental demonstration of enhancing pump absorption rate in cladding-pumped ytterbium-doped fiber lasers using pump-coupling long-period fiber gratings  

Microsoft Academic Search

A long-period fiber grating (LPFG) was inscribed in a single-mode fiber and was spliced with a ytterbium (Yb)-doped double-clad fiber in order to couple pump radiation of the inner cladding into the core in a cladding-pumped fiber laser. The use of an LPFG permits a partial core-pumping scheme in a cladding-pumping fiber laser because a portion of the pump radiation

Seungin Baek; Sookyoung Roh; Yoonchan Jeong; Byoungho Lee

2006-01-01

247

Design of ultrahigh brightness solar-pumped disk laser.  

PubMed

To significantly improve the solar-pumped laser beam brightness, a multi-Fresnel lens scheme is proposed for side-pumping either a single-crystal Nd:YAG or a core-doped ceramic Sm(3+) Nd:YAG disk. Optimum laser system parameters are found through ZEMAX and LASCAD numerical analysis. An ultrahigh laser beam figure of merit B of 53 W is numerically calculated, corresponding to a significant enhancement of more than 180 times over the previous record. 17.7 W/m(2) collection efficiency is also numerically attained. The strong thermal effects that have hampered present-day rod-type solar-pumped lasers can also be largely alleviated. PMID:22968278

Liang, Dawei; Almeida, Joana

2012-09-10

248

A kinetic model for a solar-pumped iodine laser  

Microsoft Academic Search

Good agreement between the theoretical predictions and the experimental data is found for a flashlamp-pumped iodine laser for different fill pressures and different lasants (i-C3F7I, n-C4F9I, and t-C4F9I). The following loss mechanisms of the laser output power have been identified: a relatively large amount of initial molecular iodine in the fill gas and laser light scattering as a function of

L. V. Stock; J. W. Wilson

1988-01-01

249

A solar simulator-pumped atomic iodine laser  

Microsoft Academic Search

An atomic iodine laser, a candidate for the direct solar-pumped gas laser, was excited with a 4-kW beam from a xenon arc solar simulator. Continuous lasing at 1.315 micron for over 10 ms was obtained for static filling of n-C3F7I vapor. By momentarily flowing the lasant, a 30-Hz pulsed output was obtained for about 200 ms. The peak laser power

J. H. Lee; W. R. Weaver

1981-01-01

250

A solar simulator-pumped atomic iodine laser  

Microsoft Academic Search

An atomic iodine laser, a candidate for the direct solar-pumped gas laser, was excited with a 4-kW beam from a xenon arc solar simulator. Continuous lasing at 1.315 ?m for over 10 ms was obtained for static filling of n-C3F7I vapor. By momentarily flowing the lasant, a 30-Hz pulsed output was obtained for about 200 ms. The peak laser power

Ja H. Lee; W. R. Weaver

1981-01-01

251

Electron beam pumped krypton fluoride lasers for fusion energy  

Microsoft Academic Search

High-energy electron beam pumped krypton fluoride (KrF) gas lasers are an attractive choice for inertial fusion energy (IFE). Their short wavelength and demonstrated high beam uniformity optimizes the laser-target physics, and their pulsed power technology scales to a large system. This paper presents the principals of this type of laser and the progress toward developing technologies that can meet the

JOHN D. SETHIAN; MATTHEW C. MYERS; ROBERT H. LEHMBERG; PAUL C. KEPPLE; S. P. Obenschain; FRANK HEGELER; M. Friedman; MATTHEW F. WOLFORD; RUSSELL V. SMILGYS; STEPHEN B. SWANEKAMP; DOUGLAS WEIDENHEIMER; DAVID GIORGI; DALE R. WELCH; DAVID V. ROSE; STUART SEARLES

2004-01-01

252

Gain-Induced Refractive Index Changes in Resonantly Pumped Optical Pumping Injection Cavity Lasers  

NASA Astrophysics Data System (ADS)

An optical pumping injection cavity (OPIC) laser contains a type-II W active region enclosed between two GaSb/AlAsSb distributed Bragg reflector mirrors, where the thickness of the etalon cavity surrounded by the mirrors is tuned to the desired pump wavelength. Multiple reflections of the pump photons result in more efficient absorption of the pump beam and consequently higher efficiencies and lower lasing thresholds. An optical parametric oscillator is used to pump the OPIC lasers at resonance, where the threshold pump intensities are minimized and output efficiencies are maximized. The resonant pump wavelength is found to vary quadratically with temperature, not linearly as would be expected from temperature-dependence of the lattice constant and refractive indices. Possible sources of this nonlinearity are lattice heating and gain-induced changes in the refractive indices resulting from the increase of optical pumping intensity with temperature. Through spectral measurements using step-scan Fourier Transform Infrared spectroscopy and multilayer reflectivity modeling, the relative contributions of these possible sources of parabolic temperature dependence of resonant wavelength are investigated.

Olafsen, Linda; Bain, Lauren; Ice, Lauren; Ball, Ben

2011-03-01

253

Solar-Pumped TEM?? Mode Nd:YAG laser.  

PubMed

Here we show a significant advance in solar-pumped laser beam brightness by utilizing a 1.0 m diameter Fresnel lens and a 3 mm diameter Nd:YAG single-crystal rod. The incoming solar radiation is firstly focused by the Fresnel lens on a solar tracker. A large aspheric lens and a 2D-CPC concentrator are then combined to further compress the concentrated solar radiation along the thin laser rod within a V-shaped pumping cavity. 2.3 W cw TEM?? (M² ? 1.1) solar laser power is finally produced, attaining 1.9 W laser beam brightness figure of merit, which is 6.6 times higher than the previous record. For multimode operation, 8.1 W cw laser power is produced, corresponding to 143% enhancement in collection efficiency. PMID:24150353

Liang, Dawei; Almeida, Joana

2013-10-21

254

Potential of solar-simulator-pumped alexandrite lasers  

NASA Technical Reports Server (NTRS)

An attempt was made to pump an alexandrite laser rod using a Tamarak solar simulator and also a tungsten-halogen lamp. A very low optical laser cavity was used to achieve the threshold minimum pumping-power requirement. Lasing was not achieved. The laser threshold optical-power requirement was calculated to be approximately 626 W/sq cm for a gain length of 7.6 cm, whereas the Tamarak simulator produces 1150 W/sq cm over a gain length of 3.3 cm, which is less than the 1442 W/sq cm required to reach laser threshold. The rod was optically pulsed with 200 msec pulses, which allowed the alexandrite rod to operate at near room temperature. The optical intensity-gain-length product to achieve laser threshold should be approximately 35,244 solar constants-cm. In the present setup, this product was 28,111 solar constants-cm.

Deyoung, Russell J.

1990-01-01

255

Passively Q-switched diode-pumped Er:YAG solid-state laser  

E-print Network

light is provided by a fiber-coupled laser diode from QPC with a 40 active imaging or Lidar. The pump sources are either Er:Yb fiber lasers operating at 1532 nm [1] or laser] with a diffraction limited Er:Yb fiber laser as pump source. Recently, directly diode-pumped emitters achieved 8 W

Paris-Sud XI, Université de

256

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

PubMed

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

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

2014-11-17

257

Direct solar pumping of semiconductor lasers: A feasibility study  

NASA Technical Reports Server (NTRS)

The primary goals of the feasibility study are the following: (1) to provide a preliminary assessment of the feasibility of pumping semiconductor lasers in space directly focused sunlight; and (2) to identify semiconductor laser structures expected to operate at the lowest possible focusing intensities. It should be emphasized that the structures under consideration would provide direct optical-to-optical conversion of sunlight into laser light in a single crystal, in contrast to a configuration consisting of a solar cell or battery electrically pumping a current injection laser. With external modulation, such lasers may prove to be efficient sources for intersatellite communications. We proposed to develop a theoretical model of semiconductor quantum-well lasers photopumped by a broadband source, test it against existing experimental data where possible, and apply it to estimating solar pumping requirements and identifying optimum structures for operation for operation at low pump intensities. This report outlines our progress toward these goals. Discussion of several technical details are left to the attached summary abstract.

Anderson, Neal G.

1991-01-01

258

Strong terahertz radiation from air plasmas generated by an aperture-limited Gaussian pump laser beam  

SciTech Connect

Terahertz radiation generated by focusing the fundamental laser pulse and its second harmonic into ambient air strongly saturates with increasing pump laser energy. We demonstrate a simple method to control the Gaussian pump laser beam to improve the output of terahertz radiation with an adjustable aperture. With the optimal aperture-limited pump laser beams, the terahertz wave amplitudes can be enhanced by more than eight times depending on the pump laser parameters than those of aperture-free cases.

Peng Xiaoyu; Toncian, Toma; Jung, Ralph; Willi, Oswald [Institut fuer Laser-und Plasmaphysik, Heinrich-Heine-Universitaet Duesseldorf, Duesseldorf, 40225 (Germany); Li Chun; Li Yutong; Wang Weimin; Wang Shoujun; Liu Feng [Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100080 (China); Chen Min; Pukhov, Alexander [Institut fuer Theoretische physik I, Heinrich-Heine-Universitaet Duesseldorf, Duesseldorf, 40225 (Germany); Sheng Zhengming; Zhang Jie [Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100080 (China); Department of Physics, Shanghai Jiao Tong University, Shanghai, 200240 (China)

2009-03-09

259

New concepts for compact diode-pumped femtosecond lasers  

NASA Astrophysics Data System (ADS)

We report the successful implementation of Gires-Tournois and chirped mirrors in a diode-pumped, Kerr-lens mode-locked Cr:LiSGaF laser. The laser delivered 30 mW of 79 fs, nearly transform limited pulses at 855 nm and 90 MHz repetition rate. The mirror-dispersion controlled cavity is compared to our prism setup and pulse width limitations in diode pumped Cr:LiSGaF/Cr:LiSAF lasers are identified. Mode matching calculations of pump beam and cavity mode are presented to optimize low threshold, highly efficient fs-operation. Following this analysis a compact prismless design of roughly shoe box size is suggested, which incorporates an additional high n2 element to enhance stability.

Gaebel, Kai; Russbueldt, P.; Rotarius, G.; Bette, H.; Lebert, Rainer; Du, Keming; Loosen, Peter; Poprawe, Reinhart; Valster, Adriaan

1997-08-01

260

Frequency-tunable optically pumped carbon monoxide laser  

Microsoft Academic Search

Single line, frequency tunable lasing was observed in an optically pumped, repetitively pulsed, room temperature CO laser for the first time. The R(0) and R(7) ro-vibrational transitions in the (2,0) overtone of CO at 2.3 micrometer were optically pumped with a high-energy optical parametric oscillator (OPO). Single line lasing was observed on (2,1) P(2)-P(17) transitions and R(0)-R(11) transitions (covering wavelengths

John E. McCord; Andrei A. Ionin; Steven P. Phipps; Peter G. Crowell; Alan I. Lampson; John K. McIver; Gordon D. Hager

2000-01-01

261

Environmental testing of a diode-laser-pumped Nd:YAG laser and a set of diode-laser-arrays  

Microsoft Academic Search

Results of the environmental test of a compact, rigid and lightweight diode-laser-pumped Nd:YAG laser module are discussed. All optical elements are bonded onto the module using space applicable epoxy, and two 200 mW diode laser arrays for pump sources are used to achieve 126 mW of CW output with about 7 percent electrical-to-optical conversion efficiency. This laser assembly and a

H. Hemmati; J. R. Lesh

1989-01-01

262

Composition and method of preparation of solid state dye laser rods  

DOEpatents

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.).

Hermes, Robert E. (Los Alamos, NM)

1992-01-01

263

Pump and probe spectroscopy with continuous wave quantum cascade lasers.  

PubMed

This paper details infra-red pump and probe studies on nitric oxide conducted with two continuous wave quantum cascade lasers both operating around 5 ?m. The pump laser prepares a velocity selected population in a chosen rotational quantum state of the v = 1 level which is subsequently probed using a second laser tuned to a rotational transition within the v = 2 ? v = 1 hot band. The rapid frequency scan of the probe (with respect to the molecular collision rate) in combination with the velocity selective pumping allows observation of marked rapid passage signatures in the transient absorption profiles from the polarized vibrationally excited sample. These coherent transient signals are influenced by the underlying hyperfine structure of the pump and probe transitions, the sample pressure, and the coherent properties of the lasers. Pulsed pump and probe studies show that the transient absorption signals decay within 1 ?s at 50 mTorr total pressure, reflecting both the polarization and population dephasing times of the vibrationally excited sample. The experimental observations are supported by simulation based upon solving the optical Bloch equations for a two level system. PMID:24511944

Kirkbride, James M R; Causier, Sarah K; Dalton, Andrew R; Weidmann, Damien; Ritchie, Grant A D

2014-02-01

264

Diode-Pumped, Q-Switched, Frequency-Doubling Laser  

NASA Technical Reports Server (NTRS)

Experimental Q-switched, diode-pumped, intracavity-frequency-doubling laser generates pulses of radiation at wavelength of 532 nm from excitation at 810 nm. Principal innovative feature distinguishing laser from others of its type: pulsed operation of laser at pulse-repetition frequencies higher than reported previously. Folded resonator keeps most of second-harmonic radiation away from Q-switcher, laser crystal, and laser diodes. Folding mirror highly reflective at fundamental laser wavelength and highly transmissive at second-harmonic laser wavelength. By virtue of difference of about 0.6 percent between reflectivities in two polarizations at fundamental wavelength, folding mirror favors polarized oscillation at fundamental wavelength. This characteristic desirable for doubling of frequency in some intracavity crystals.

Hemmati, Hamid; Lesh, James R.

1993-01-01

265

Optically pumped Iodine monofluoride B/sup 3/Pi(O/sup +/). -->. X/sup 1/. sigma. /sup +/ laser  

SciTech Connect

An optically pumped iodine monofluoride laser operating on the B/sup 3/Pi(O/sup +/)..-->..X/sup 2/..sigma../sup +/ system has been demonstrated. Ground-state IF was produced by the reaction of I/sub 2/+F/sub 2/ and subsequently excited with a high-energy, broadband dye laser. Lasing was observed on the (2,10), (3,11), (4,9), and (4,10) transitions covering the wavelength range 7200--6500 A.

Davis, S.J.; Hanko, L.

1980-10-15

266

Fiber laser pumped high energy cryogenically cooled Ho:YLF laser  

NASA Astrophysics Data System (ADS)

In this paper we report on a high energy, low repetition rate 2-micron-laser, with high conversion efficiency in terms of output energy per pump power. The laser consists of a Ho3+-doped LiYF4 (YLF) crystal cooled to cryogenic temperatures in an unstable resonator, pumped by a thulium fiber laser. The cooling to 77 K makes Ho:YLF a quasi four level laser system, which greatly enhances the extraction efficiency. We achieved 356 mJ in Q-switched operation at 1 Hz PRF when pumping the laser with 58 W for 36 ms. The high beam quality from the fiber laser and the use of an unstable resonator with a graded reflectivity mirror (GRM) resulted in a high quality laser beam with a M2-value of 1.3.

Lippert, Espen; Fonnum, Helge; Stenersen, Knut

2012-09-01

267

Optimization of rod diameter in solid state lasers side pumped with multiple laser diode arrays  

NASA Technical Reports Server (NTRS)

Results of a study to determine the optimum laser rod diameter for maximum output energy in a solid state neodymium laser transversely pumped with multiple laser diode arrays are reported here. Experiments were performed with 1.0 mm, 1.5 mm and 2.0 mm rod radii of both neodymium doped Y3Al5O12 (Nd:YAG) and La2Be2O5 (Nd:BeL) pumped with laser diode arrays having a maximum combined energy of 10.5 mJ. Equations were derived which predict the optimum rod radius and corresponding output mirror reflectivity for a given laser material and total pump energy. Predictions of the equations agreed well with the experiments for each of the laser materials which possessed significantly different laser properties from one another.

Sims, Newton, Jr.; Chamblee, Christyl M.; Barnes, Norman P.; Lockard, George E.; Cross, Patricia L.

1992-01-01

268

Resonantly pumped, high peak power Er:YAG laser  

NASA Astrophysics Data System (ADS)

The high peak power hybrid Er:YAG laser, resonantly pumped at the wavelength of 1532 nm was developed. The fused silica acousto-optic modulator driven by 10 W of RF power was deployed as the Q-switch for such a laser. For the best case of Q-switching regime the pulses of 110 kW peak power (4 mJ, 37 ns) were reached at the pump power of 7.8 W and the repetition rate of 500 Hz.

Zendzian, W.; Ga?ecki, L.; Jabczynski, J. K.; Kwiatkowski, J.; Gorajek, L.; Nemec, M.; Jelinkova, H.; Sulc, J.

2010-02-01

269

Graphene surface emitting terahertz laser: Diffusion pumping concept  

NASA Astrophysics Data System (ADS)

We suggest a concept of a tunable graphene-based terahertz (THz) surface emitting laser with diffusion pumping. We employ significant difference in the electronic energy gap of graphene and a typical wide-gap semiconductor, and demonstrate that carriers generated in the semiconductor can be efficiently captured by graphene resulting in population inversion and corresponding THz lasing from graphene. We develop design principles for such a laser and estimate its performance. We predict up to 50 W/cm2 terahertz power output for 100 kW/cm2 pump power at frequency around 10 THz at room temperature.

Davoyan, Arthur R.; Morozov, Mikhail Yu.; Popov, Vyacheslav V.; Satou, Akira; Otsuji, Taiichi

2013-12-01

270

Graphene surface emitting terahertz laser: Diffusion pumping concept  

SciTech Connect

We suggest a concept of a tunable graphene-based terahertz (THz) surface emitting laser with diffusion pumping. We employ significant difference in the electronic energy gap of graphene and a typical wide-gap semiconductor, and demonstrate that carriers generated in the semiconductor can be efficiently captured by graphene resulting in population inversion and corresponding?THz lasing from graphene. We develop design principles for such a laser and estimate its performance. We predict up to 50?W/cm{sup 2} terahertz power output for 100?kW/cm{sup 2} pump power at frequency around 10?THz at room temperature.

Davoyan, Arthur R., E-mail: davoyan@seas.upenn.edu [Kotelnikov Institute of Radio Engineering and Electronics (Saratov Branch), Russian Academy of Sciences, Saratov 410019, Russia and Department of Electrical and Systems Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104 (United States); Morozov, Mikhail Yu.; Popov, Vyacheslav V. [Kotelnikov Institute of Radio Engineering and Electronics (Saratov Branch), Russian Academy of Sciences, Saratov 410019 (Russian Federation)] [Kotelnikov Institute of Radio Engineering and Electronics (Saratov Branch), Russian Academy of Sciences, Saratov 410019 (Russian Federation); Satou, Akira; Otsuji, Taiichi [Research Institute of Electrical Communication (RIEC), Tohoku University, Sendai, Miyagi 980-8577 (Japan)] [Research Institute of Electrical Communication (RIEC), Tohoku University, Sendai, Miyagi 980-8577 (Japan)

2013-12-16

271

Conceptual Design Studies of a Laser Diode Pumped Solid State Laser System for the Laser Fusion Reactor Driver  

Microsoft Academic Search

We have developed a conceptual designing technique of a laser diode pumped solid state laser system having high peak power, high efficiency, good beam quality, and high repetition rate. Using this technique, we evaluated the feasibility of the systems with several solid state laser materials for the laser fusion reactor driver with 10 MJ blue output, 10% overall efficiency, and

Kenta Naito; Masanobu Yamanaka; Masahiro Nakatsuka; Tadashi Kanabe; Kunioki Mima; Chiyoe Yamanaka; Sadao Nakai

1992-01-01

272

Fiber-coupled high brightness high power diode laser for solid-state laser pumping and material processing  

Microsoft Academic Search

Two applications emerge as drivers for higher brightness fiber-coupled diode lasers: advanced solid-state pumping schemes and materials processing. In contrast to the well-established side-pumping schemes of laser rods, advanced pumping schemes for today's solid-state lasers make use of the high brightness of the pump sources to increase the performance and efficiency of the solid-state laser. Materials processing applications such as

Bodo Ehlers; Stefan Heinemann; Falk Doerfel

2003-01-01

273

Further development of high-power pump laser diodes  

NASA Astrophysics Data System (ADS)

AlGaAs/InGaAs based high power pump laser diodes with wavelength of around 980 nm are key products within erbium doped fiber amplifiers (EDFA) for today's long haul and metro-communication networks, whereas InGaAsP/InP based laser diodes with 14xx nm emission wavelength are relevant for advanced, but not yet widely-used Raman amplifiers. Due to the changing industrial environment cost reduction becomes a crucial factor in the development of new, pump modules. Therefore, pump laser chips were aggressively optimized in terms of power conversion and thermal stability, which allows operation without active cooling at temperatures exceeding 70°C. In addition our submarine-reliable single mode technology was extended to high power multi-mode laser diodes. These light sources can be used in the field of optical amplifiers as well as for medical, printing and industrial applications. Improvements of pump laser diodes in terms of power conversion efficiency, fiber Bragg grating (FBG) locking performance of single mode devices, noise reduction and reliability will be presented.

Schmidt, Berthold; Lichtenstein, Norbert; Sverdlov, Boris; Matuschek, Nicolai; Mohrdiek, Stefan; Pliska, Tomas; Mueller, Juergen; Pawlik, Susanne; Arlt, Sebastian; Pfeiffer, Hans-Ulrich; Fily, Arnaud; Harder, Christoph

2003-12-01

274

The chemically pumped oxygen-iodine laser  

Microsoft Academic Search

The present status of the chemical oxygen-iodine laser is discussed. The pertinent processes occurring in the chemical O2 generator, the O2(1Delta) transport region, and the nozzle are reviewed. The energy transfer kinetics, laser gain, and the performance and device efficiency are examined.

P. V. Avizonis; G. Hasen; K. A. Truesdell

1990-01-01

275

Multiple oscillation of whispering-gallery-mode dye lasers in green and orange regions using mixed-dye-doped solid microspheres  

NASA Astrophysics Data System (ADS)

Mixed-dye-doped solid microspheres are excited by a transversely excited-atmospheric ultraviolet N2 laser to obtain a multiple oscillation of a whispering-gallery-mode (WGM) dye laser in both green and orange regions. The multiple oscillation exhibits separate modes of WGMs in both spectral regions.

Taniguchi, Hiroshi; Tanosaki, Shinji; Yamada, Hiroshi; Fujiwara, Tamiya; Baba, Mamoru

1993-06-01

276

Temperature distribution of laser crystal in LD end-pumped Nd:YAG/LBO blue laser  

NASA Astrophysics Data System (ADS)

In this study, LD end-pumped Nd:YAG/LBO solid state blue laser is realized by even hollow cavity. A thermal distribution model of Nd:YAG crystal is established. Based on the calculation, the temperature distribution of laser crystal is obtained. The results show that the temperature decreases from the pump end to the launch end exponentially. When the pumping power is 10 W and the radius of pumping beams is 240?m, a biggest output power 1.06 W of blue light is achieved, giving an optical conversion efficiency of 10.6%.

Zhang, Lei; Zheng, Yibo; Li, Simian; Jia, Liping; Kang, Junjian

2012-11-01

277

Solar-simulator-pumped atomic iodine laser kinetics  

NASA Technical Reports Server (NTRS)

The literature contains broad ranges of disagreement in kinetic data for the atomic iodine laser. A kinetic model of a solar-simulator-pumped iodine laser is used to select those kinetic data consistent with recent laser experiments at the Langley Research Center. Analysis of the solar-simulator-pumped laser experiments resulted in the following estimates of rate coefficients: for alkyl radical (n-C3F7) and atomic iodine (I) recombination, 4.3 x 10 to the 11th power (1.9) + or - cu cm/s; for n-C3F7I stabilized atomic iodine recombination (I + I) 3.7 x 10 to the -32nd power (2.3) + or -1 cm to the 6th power/s; and for molecular iodine (I2) quenching, 3.1 x 10 to the -11th power (1.6) + or - 1 cu cm/s. These rates are consistent with the recent measurements.

Wilson, H. W.; Raju, S.; Shiu, Y. J.

1983-01-01

278

Line-Focus Generation for X-Ray Laser Pumping  

NASA Astrophysics Data System (ADS)

Down-scaling of X-ray lasers towards shorter wavelengths imposes the need for higher irradiance of the pump laser systems. Typically, for a factor of 2 reduction in wavelength, a factor of ˜10 increase in irradiance was so far required. This discourages the use of refractive optics after the compressor stage of the high-power CPA laser systems commonly used for pumping X-ray lasers due to increasing nonlinear phase distortion (B-Integral). We present ray-tracing calculations of alternative focusing schemes applying reflective optics for grazing-incidence line-focus generation. The proposed mirrors deliver a narrow and shortened line focus from a high-aperture input beam, yielding an increase of irradiance on target.

Staub, F.; Bleiner, D.; Jia, F.; Balmer, J. E.

279

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

SciTech Connect

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.

Khoobehi, B.; Char, C.A.; Peyman, G.A.; Schuele, K.M. (Louisiana State Univ. Medical Center, School of Medicine, New Orleans (USA))

1990-01-01

280

Nuclear pumped laser for next step ICF driver  

SciTech Connect

A conceptual design for an alternative laser driver for the Laboratory Microfusion Facility (LMF) is presented. A pulsed fission reactor is used to excite an oxygen-iodine laser in this study based on preliminary data on nuclear pumping of O/sub 2/(/sup 1/..delta..). Although a working NPL of this specific type has not yet been assembled, the authors believe this concept holds great potential both as a test facility driver and as a future power reactor.

Balog, S.; Chung, H.; Doczy, M.; Duraski, R.; Hutcheson, M.; Eglezopoulos, L.R.; Russ, D.

1989-03-01

281

Flashlamp-pumped iodine laser with an optically thick medium  

Microsoft Academic Search

A procedure is described for numerical calculations of the temporal and radial dependences of the laser radiation power and energy and also of the refractive index for free-oscillation and inversion-storage conditions in the case of a cylindrically symmetric pump source positioned directly in the gaseous active medium. Some results of these calculations as applied to a CF3I iodine photodissociation laser

G. N. Vinokurov; V Yu Zalesski?; P. I. Krepostnov

1980-01-01

282

Characteristics of the electron beam pumped iodine monofluoride laser  

Microsoft Academic Search

Electron beam pumping of Ar\\/CF3I\\/NF3 mixtures yields optical pulse lengths approximately 0.5 microsec from iodine monofluoride. Laser efficiency in this system is approximately 0.04 percent. Laser performance is limited by the formation of molecular iodine. The formation of molecular iodine in the excited state reduces the number of iodine atoms available to form excited-state IF. In the ground state, molecular

L. F. Champagne; J. E. Ehrlich

1983-01-01

283

Characteristics of the electron beam pumped iodine monofluoride laser  

Microsoft Academic Search

Electron beam pumping of Ar\\/CFâI\\/NFâ mixtures yields optical pulse lengths about 0.5 ..mu..s from iodine monofluoride. Laser efficiency in this system is about0.04 percent. Laser performance is limited by the formation of molecular iodine. The formation of molecular iodine in the excited state (Iâ) reduces the number of iodine atoms available to form IF. In the ground state, molecular iodine

L. F. Champagne; J. E. Ehrlich

1983-01-01

284

Grazing incidence pumping for high efficiency x-ray lasers  

Microsoft Academic Search

Over the last decade, most laser-driven collisional excitation x-ray lasers have relied on the absorption of the pump energy incident at normal incidence to a pre-formed plasma. The main advantage is that the inversion can be created at various plasma regions in space and time where the amplification and ray propagation processes are best served. The main disadvantage is that

J. Dunn; R. Keenan; V. N. Shlyaptsev

2005-01-01

285

Solar Pumped High Power Solid State Laser for Space Applications  

NASA Technical Reports Server (NTRS)

Highly coherent laser light provides a nearly optimal means of transmitting power in space. The simplest most direct means of converting sunlight to coherent laser light is a solar pumped laser oscillator. A key need for broadly useful space solar power is a robust solid state laser oscillator capable of operating efficiently in near Earth space at output powers in the multi hundred kilowatt range. The principal challenges in realizing such solar pumped laser oscillators are: (1) the need to remove heat from the solid state laser material without introducing unacceptable thermal shock, thermal lensing, or thermal stress induced birefringence to a degree that improves on current removal rates by several orders of magnitude and (2) to introduce sunlight at an effective concentration (kW/sq cm of laser cross sectional area) that is several orders of magnitude higher than currently available while tolerating a pointing error of the spacecraft of several degrees. We discuss strategies for addressing these challenges. The need to remove the high densities of heat, e.g., 30 kW/cu cm, while keeping the thermal shock, thermal lensing and thermal stress induced birefringence loss sufficiently low is addressed in terms of a novel use of diamond integrated with the laser material, such as Ti:sapphire in a manner such that the waste heat is removed from the laser medium in an axial direction and in the diamond in a radial direction. We discuss means for concentrating sunlight to an effective areal density of the order of 30 kW/sq cm. The method integrates conventional imaging optics, non-imaging optics and nonlinear optics. In effect we use a method that combines some of the methods of optical pumping solid state materials and optical fiber, but also address laser media having areas sufficiently large, e.g., 1 cm diameter to handle the multi-hundred kilowatt level powers needed for space solar power.

Fork, Richard L.; Laycock, Rustin L.; Green, Jason J. A.; Walker, Wesley W.; Cole, Spencer T.; Frederick, Kevin B.; Phillips, Dane J.

2004-01-01

286

Continuous-wave diode-pumped solid-state laser with an intracavity fiber Bragg grating  

E-print Network

Bragg grating, and the output laser beam is then directly coupled in the optical fiber. The singleContinuous-wave diode-pumped solid-state laser with an intracavity fiber Bragg grating Sylvie Yiou concept of laser that benefits from both fiber and laser crystals: a cw diode-pumped solid-state laser

Paris-Sud XI, Université de

287

Pulsed dye laser treatment for facial flat warts.  

PubMed

The facial flat wart is not only a contagious viral disease, but also a cause of a distressing cosmetic problem. Although there are many therapeutic options, including salicylic acid, imiquimod, cryotherapy, retinoids, intralesional immunotherapy, and topical 5-aminolevulinic acid photodynamic therapy among others, no monotherapy has been proved to achieve complete remission in every case. Treatment with pulsed dye laser (PDL) seems to be a promising therapeutic option. To assess the efficacy and safety of PDL in a series of patients with viral flat warts on the face, in this prospective study, 32 patients were treated with PDL at 595-nm wavelength, a laser energy density of 9 or 14?J/cm(2) with a spot size of 7 or 5?mm, respectively, with air cooling and a pulse duration of 0.5?millisecond. A complete response was noted in 14 patients (44%), and an excellent response was observed in 18 patients (56%) with 1-year follow-up, with only four recurrences. No significant side effects were reported except intense transitory purpuric response. We consider that PDL is a good option of treatment for flat warts on the face due to its good clinical results, fast response, and low incidence of side effects. PMID:24502309

Grillo, E; Boixeda, P; Ballester, A; Miguel-Morrondo, A; Truchuelo, T; Jaén, P

2014-01-01

288

Skin welding using pulsed laser radiation and a dye  

NASA Astrophysics Data System (ADS)

Previous skin welding studies have used continuous wave (CW) delivery of radiation. However, heat diffusion during irradiation prevents strong welds from being achieved without creating large zones of thermal damage to surrounding tissue. This damage may prevent normal wound healing. Strong welds and minimal thermal damage can be achieved by introducing a dye and delivering the radiation in a pulsed mode. Two-cm-long, full-thickness incisions were made in guinea pig skin. India ink was used as an absorber, and egg white albumin was used as an adhesive. A 5-mm-diameter spot of CW, 1.06-micrometer Nd:YAG laser radiation was scanned over the weld site, producing 100 millisecond pulses. The cooling time between scans and number of scans was varied. Thermal damage zones were measured using a transmission polarizing microscope to identify birefringence changes in tissue. Tensile strengths were measured using a tensiometer. For pulsed welding and long cooling times, weld strengths of 2.4 kg/cm2 were measured, and thermal damage to the epidermis was limited to approximately 500 micrometers. With CW welding, comparable weld strengths resulted in approximately 2700 micrometer of thermal damage. CW laser radiation weld strengths were only 0.6 kg/cm2 when thermal damage in the epidermis was limited to approximately 500 micrometers.

Fried, Nathaniel M.; Walsh, Joseph T., Jr.

1998-07-01

289

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

NASA Astrophysics Data System (ADS)

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.

Smucler, Roman; Horak, Ladislav; Mazanek, Jiri

1999-06-01

290

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

SciTech Connect

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.

Erickson, G.F.

1987-01-01

291

Optically Pumped Atomic Rubidium Lasers: Two-Photon and Exciplex Excitation Mechanisms  

NASA Astrophysics Data System (ADS)

The Doppler-broadened two-photon absorption (TPA) cross-section for the 52S1/2 ? 52 D5/2 transition in Rb is measured using direct absorption methods. The selection rule |DeltaF| ? 2 applied to both isotopes yields 17 transitions in 3 Doppler limited lines. A detailed model of the intensity profile was also developed to account for a focused Gaussian beam (with an M2 value of 1.09) propagating through a two-photon absorption medium. A peak absorbance of 24% was observed for an intensity of 6.28 kWcm2 at the focus, a Rb density of 4.6x1015 cm-3 , and a path length of 15 cm. Alkali concentrations from 1.61 - 8.52x1015 cm -3 were monitored in the far wing of the D 2 line. Extracting the hyperfine-broadened TPA cross-section from 87 test configurations, while varying the pump power, alkali concentration and focal length, yielded an error-weighted average of 6.75x10^-21 cm4W with a standard deviation of 3.61x10-21 cm4W. This cross-section is sufficient for a pulsed dye laser to bleach the pump transition in the Two-Photon Pumped Alkali Laser (TPAL) that lases at 420 nm and 5.2 microm. Optically pumped atomic rubidium lasers pumped in the blue satellite of the D2 line from the ground Rb-Ar or Rb-Kr collision pair to the dissociative B2S+1/2 state produce laser emission at 780.2 nm. Lasing is achieved for pump wavelengths of 752.3 to greater than 760 nm for the Rb-Ar system and 757.1 -- 760.4 nm for the Rb-Kr system. Slope efficiencies increase with both Rb and Ar concentrations and exceed 0.25% using a heat pipe configuration. The gain is very high with photon build-up times of 1--3.7 ns. Laser induced heating and subsequent condensation of alkali vapor in the heat pipe configuration currently limits operation to less than 2500 Torr.

Gallagher, Jeffrey E.

292

Dye-dispersion study at proposed pumped-storage project on Hudson River at Cornwall, New York  

USGS Publications Warehouse

Data were collected during a dye-dispersion study on a 6-mile, tide-affected reach of the Hudson River near the proposed Cornwall Pumped Storage Project on September 21-22, 1977. The results indicated that complete mixing did not occur during the first tidal cycle but was complete after two or more cycles. The fluorometric dye-tracing procedure was used to determine the dispersion characteristics of the water mass. Rhodamine WT dye, 20-percent solution, was continuously injected on the west side of the river throughout an ebb tide, and its movement was monitored during a 30-hour period. Samples were collected both individually and continuously. Automatic dye samplers were used at selected cross sections near each bank. Bathymetric measurements were made at eight cross sections between Newburgh and West Point to determine the depths. (Woodard-USGS)

Dunn, Bernard; Gravlee, George C.

1978-01-01

293

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

NASA Astrophysics Data System (ADS)

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.

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

2014-08-01

294

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

PubMed

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 ((1)S0-(3)P0) 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. PMID:25173252

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

2014-08-01

295

High power high repetition rate VCSEL array side-pumped pulsed blue laser  

NASA Astrophysics Data System (ADS)

High power, kW-class, 808 nm pump modules based on the vertical-cavity surface-emitting laser (VCSEL) technology were developed for side-pumping of solid-state lasers. Two 1.2 kW VCSEL pump modules were implemented in a dual side-pumped Q-switched Nd:YAG laser operating at 946 nm. The laser output was frequency doubled in a BBO crystal to produce pulsed blue light. With 125 ?s pump pulses at a 300 Hz repetition rate 6.1 W QCW 946 nm laser power was produced. The laser power was limited by thermal lensing in the Nd:YAG rod.

van Leeuwen, Robert; Zhao, Pu; Chen, Tong; Xu, Bing; Watkins, Laurence; Seurin, Jean-Francois; Xu, Guoyang; Miglo, Alexander; Wang, Qing; Ghosh, Chuni

2013-03-01

296

The chemically pumped iodine laser as a fusion driver  

Microsoft Academic Search

A chemically pumped iodine laser is evaluated for fusion requirements. Efficiencies greater than 8 percent and long energy storage times are predicted, with high repetition rates and elimination of pulsed power supplies. Bibtex entry for this abstract Preferred format for this abstract (see Preferences) Find Similar Abstracts: Use: Authors Title Keywords (in text query field) Abstract Text Return: Query Results

G. E. Busch

1980-01-01

297

Modeling of a solar-pumped iodine laser  

Microsoft Academic Search

The direct conversion in space of solar radiation into laser radiation for power transmission to earth, satellites, or deep space probes shows promise as a reasonably simple technology and may have cost advantage in deployment and greater reliability compared to other methods of space power generation and transmission. The main candidates for solar pumping are the gas dynamic, photochemical, and

J. W. Wilson; J. H. Lee

1980-01-01

298

Modeling of a solar-pumped iodine laser  

Microsoft Academic Search

The direct conversion in space of solar radiation into laser radiation for power transmission to earth, satellites, or deep space probes shows promise as a reasonably simple technology and may have cost advantage in deployment and greater reliability compared to other methods of space power generation and transmission. The main candidates for solar pumping are the gas dynamic, photochemical, and

J. W. Wilson; J. H. Lee

2009-01-01

299

Anomalous dispersion and the pumping of far infrared (FIR) lasers  

NASA Technical Reports Server (NTRS)

It is shown that the anomalous dispersion at the pump transition in molecular far-infrared lasers (FIR) can lead to sizable focusing and defocusing effects. Criteria for beam spreading and trapping are considered with CH2F as an example.

Lawandy, N. M.

1978-01-01

300

Computer modeling of an optically pumped hydrogen halide laser  

Microsoft Academic Search

Kinetic modelling of a short-pulse optically pumped hydrogen fluoride laser has been undertaken. This work utilizes scaling laws to obtain many of the rate constants describing the numerous energy transfer reactions. Because of the numerous differential equations and energy exchange reactions that must be considered in a complete model, a truncated version has been constructed which includes the processes which

Nicholas P. Machara; Gordon D. Hager

1993-01-01

301

Nuclear-driven flashlamp pumping of the atomic iodine laser  

SciTech Connect

This report is a study of the atomic iodine laser pumped with nuclear- excited XeBr fluorescence. Preliminary experiments, conducted in the TRIGA reactor investigated the fluorescence of the excimer XeBr under nuclear pumping with {sup 10}B and {sup 3}He, for use as a flashlamp gas to stimulate the laser. These measurements included a determination of the fluorescence efficiency (light emitted in the wavelength region of interest, divided by energy deposited in the gas) of XeBr under nuclear pumping, with varying excimer mixtures. Maximum fluorescence efficiencies were approximately 1%. In order to better understand XeBr under nuclear excitation, a kinetics model of the system was prepared. The model generated the time-dependant concentrations of 20 reaction species for three pulse sizes, a TRIGA pulse, a fast burst reactor pulse, and an e-beam pulse. The modeling results predicted fluorescence efficiencies significantly higher (peak efficiencies of approximately 10%) than recorded in the fluorescence experiments. The cause of this discrepancy was not fully determined. A ray tracing computer model was also prepared to evaluate the efficiency with which nuclear-induced fluorescence generated in one cavity of a laser could be coupled into another cavity containing an iodine lasant. Finally, an experimental laser cell was constructed to verify that nuclear-induced XeBr fluorescence could be used to stimulate a laser. Lasing was achieved at 1.31 micron in the TRIGA using C{sub 3}F{sub 7}I, a common iodine lasant. Peak laser powers were approximately 20 mW. Measured flashlamp pump powers at threshold agreed well with literature values, as did lasant pressure dependency on laser operation.

Miley, G.H.

1992-03-01

302

Continuously tunable diode-pumped Tm:YAP laser  

NASA Astrophysics Data System (ADS)

Tunable solid-state laser sources emitting in the 2 ?m wavelength region are important for applications in atmospheric monitoring and laser radar because many molecular absorption lines are present there. We report on continuously tunable operation of a diode pumped Tm:YAP laser, which is among the most efficient laser materials emitting in the 1.9-2 ?m spectral band, while continuous tuning of this material has not yet been reported. The 3mm long a-cut (Pbnm) crystal sample with 4% at. doping was used. The 400 ?m fiber was used to deliver up to 17W of pump power to the coupling optics. The differential efficiency in respect to the absorbed pump power reached 57% while the attained optical-to-optical efficiency was 48%. The maximal output of 4.8W was only limited by the available pump power and relatively low sample absorption. The free running wavelength was measured at 1.99 ?m. A 1.5mm thick birefringent plate made from quartz inserted under a Brewster's angle was used as a tuning element. The maximal output power of 3.85W in this set-up was obtained. The laser could be tuned from 1869nm up to 2036nm with a maximum at 1985 nm. The tuning range of over 160nm covers many important atmospheric absorption lines. In this wavelength range, the absorption depth in water changes from 100 ?m (laser wavelength 1.94 ?m) to 400 ?m (wavelength 1.87 ?m) making it potentially attractive for medical applications as a laser scalpel with variable cutting depth.

?erný, Pavel; Šulc, Jan; Jelínkova, Helena

2006-04-01

303

Different emission properties of a band edge laser pumped by picosecond and nanosecond pulses  

Microsoft Academic Search

Different emission properties of band edge laser in a face centered cubic (FCC) photonic crystal pumped by ps and ns pulse were investigated experimentally. For the case pumped by ps laser, multi-mode emission is obtained and every modes have narrow line width. For the case pumped by ns laser, there is only a single dominant mode with high output intensity

S J Chen; Y Zhou; T R Zhai; Z N Wang; D H Liu

2012-01-01

304

A kinetic model for a solar-pumped iodine laser  

SciTech Connect

Good agreement between the theoretical predictions and the experimental data is found for a flashlamp-pumped iodine laser for different fill pressures and different lasants ({ital i}-C{sub 3}F{sub 7}I, {ital n}-C{sub 4}F{sub 9}I, and {ital t}-C{sub 4}F{sub 9}I). The following loss mechanisms of the laser output power have been identified: a relatively large amount of initial molecular iodine in the fill gas and laser light scattering as a function of pressure.

Stock, L.V. (Hampton University, Hampton, VA 23668 (US)); Wilson, J.W. (NASA, Langley Research Center, Hampton, VA 23665)

1988-10-01

305

Characteristics of the electron beam pumped iodine monofluoride laser  

SciTech Connect

Electron beam pumping of Ar/CF/sub 3/I/NF/sub 3/ mixtures yields optical pulse lengths about 0.5 ..mu..s from iodine monofluoride. Laser efficiency in this system is about0.04 percent. Laser performance is limited by the formation of molecular iodine. The formation of molecular iodine in the excited state (I/sub 2/) reduces the number of iodine atoms available to form IF. In the ground state, molecular iodine (I/sub 2/) absorbs the IF laser emission at 485 and 491 nm.

Champagne, L.F.; Ehrlich, J.E.

1983-02-01

306

Negative-coupling resonances in pump-coupled lasers  

E-print Network

We consider coupled lasers, where the intensity deviations from the steady state, modulate the pump of the other lasers. Most of our results are for two lasers where the coupling constants are of opposite sign. This leads to a Hopf bifurcation to periodic output for weak coupling. As the magnitude of the coupling constants is increased (negatively) we observe novel amplitude effects such as a weak coupling resonance peak and, strong coupling subharmonic resonances and chaos. In the weak coupling regime the output is predicted by a set of slow evolution amplitude equations. Pulsating solutions in the strong coupling limit are described by discrete map derived from the original model.

T. W. Carr; M. L. Taylor; I. B. Schwartz

2005-10-28

307

Femtosecond Cr:Colquiriite Lasers Pumped by a Single Tapered Diode Laser  

E-print Network

Ti:Sapphire lasers could provide tunable femtosecond pulses in the 680-1180 nm region; however, due to the requirement of expensive green pump sources, its current cost sets a barrier to its widespread adoption. As an ...

Demirbas, Umit

308

Traveling-wave laser-produced-plasma energy source for photoionization laser pumping and lasers incorporating said  

DOEpatents

A traveling-wave, laser-produced-plasma, energy source used to obtain single-pass gain saturation of a photoionization pumped laser. A cylindrical lens is used to focus a pump laser beam to a long line on a target. Grooves are cut in the target to present a surface near normal to the incident beam and to reduce the area, and hence increase the intensity and efficiency, of plasma formation.

Sher, Mark H. (Los Altos, CA); Macklin, John J. (Stanford, CA); Harris, Stephen E. (Palo Alto, CA)

1989-09-26

309

Efficient generation of tunable VUV laser radiation below 205 nm by SFM in BBO  

Microsoft Academic Search

Design and performance characteristics of a tunable dye laser system for sum frequency mixing (SFM) in a BBO crystal are presented. The system is composed of two tunable pulsed dye lasers pumped synchronously by the second harmonic of a commercial Nd:YAG laser. The radiation produced by the first dye laser is frequency doubled by second-harmonic generation (SHG) in KDP and

U. Heitmann; M. Koetteritzsch; S. Heitz; A. Hese

1992-01-01

310

Highly efficient solar-pumped Nd:YAG laser.  

PubMed

The recent progress in solar-pumped laser with Fresnel lens and Cr:Nd:YAG ceramic medium has revitalized solar laser researches, revealing a promising future for renewable reduction of magnesium from magnesium oxide. Here we show a big advance in solar laser collection efficiency by utilizing an economical Fresnel lens and a most widely used Nd:YAG single-crystal rod. The incoming solar radiation from the sun is focused by a 0.9 m diameter Fresnel lens. A dielectric totally internally reflecting secondary concentrator is employed to couple the concentrated solar radiation from the focal zone to a 4 mm diameter Nd:YAG rod within a conical pumping cavity. 12.3 W cw laser power is produced, corresponding to 19.3 W/m(2) collection efficiency, which is 2.9 times larger than the previous results with Nd:YAG single-crystal medium. Record-high slope efficiency of 3.9% is also registered. Laser beam quality is considerably improved by pumping a 3 mm diameter Nd:YAG rod. PMID:22274224

Liang, Dawei; Almeida, Joana

2011-12-19

311

Study on the Pr:KYF ultraviolet laser at 305 nm pumped by blue laser  

NASA Astrophysics Data System (ADS)

An all-solid-state Pr:KY3F10 (Pr:KYF) laser pumped by blue laser (471 nm) has been demonstrated. With the incident pump power of 2.6 W, the maximum output power at 610 nm is 213 mW. Moreover, the intracavity second-harmonic generation (SHG) is also achieved with the maximum ultraviolet (UV) power at 305 nm of 11 mW by using a ?-BaB2O4 (BBO) nonlinear crystal.

Ni, Tian-yi; Li, Yong-liang; Zhang, Tian-yi; Ruan, Ren-qiu

2012-09-01

312

Continuous wave chemically pumped atomic iodine laser  

SciTech Connect

Cw laser action achieved on the 2p178-2p3/2 transition of the iodine atom by energy transfer from the 1 delta metastable state of O2 is discussed. The effluent from a conventional oxygen generator was mixed with molecular iodine at the entrance of a longitudinal flow laser cavity where the I2 was dissociated by a small amount of O2 (1 sigma ) that was present in the flow due to energy pooling processes. The measured output power was greater than 4MW

Benard, D.J.; Bousek, R.R.; Mcdermott, W.E.; Pchelkin, N.R.

1981-05-12

313

Experimental study of the diode pumped alkali laser (DPAL)  

NASA Astrophysics Data System (ADS)

A small-scale cesium diode-pumped alkali laser (DPAL) apparatus has been developed for fundamental researches. A commercial laser diode with volume Bragg grating outcoupler is used to pump the gain cell longitudinally. Both windows of the gain cell are set at Brewster's angle for minimum loss and maximum durability. Output coupling coefficient is continuously variable from 13% to 85% by the slanted quartz plate outcoupler inserted in the optical resonator. Small signal gain is measured with a laser diode probe at various gain cell temperatures. A 6.5 W continuouswave output with 56% optical-to-optical conversion efficiency (based on the absorbed power) has been achieved. A numerical simulation code is developed and its calculation results are in good agreement with the experiments.

Endo, Masamori; Nagaoka, Ryuji; Nagaoka, Hiroki; Nagai, Toru; Wani, Fumio

2014-02-01

314

Comparison of the Effectiveness of Nonablative Fractional Laser versus Pulsed-Dye Laser in Thyroidectomy Scar Prevention  

PubMed Central

Background The anterior neck is the site of open thyroidectomy and where postoperative scarring can cause distress to patients. Both fractional and pulsed-dye lasers are effective and safe methods for preventing and improving surgical scars. Objective This study evaluated the improvement in scar appearance with laser intervention during the wound healing process. We evaluated the effect of nonablative fractional and pulsed-dye lasers on fresh thyroidectomy scars. Methods Patients were treated 3 times at 4-week interval with a follow-up visit at the 6th month. Scars were divided into 2 halves for each optional treatment. At every visit, a questionnaire evaluating the scar and patient satisfaction was completed. Results Thirty patients completed the 6-month process. The mean Vancouver Scar Scale scores improved significantly from 8.0 to 4.6 and 8.2 to 4.7 with nonablative fractional and pulsed-dye lasers, respectively (p<0.001). However, there was no significant difference between the 2 methods (p=0.840). Conclusion There remains no consensus on the optimal treatment of scars. The present study indicates nonablative fractional and pulsed-dye lasers significantly improve scars. Nonablative fractional lasers are non-inferior to pulsed-dye lasers. Further studies are required to corroborate this finding.

Ha, Ji Min; Kim, Han Su; Cho, Eun Byul; Park, Gyeong Hun; Kim, Kwang Ho; Kim, Lee Su; Kim, Kwang Joong

2014-01-01

315

Quantum-trajectory description of laser noise with pump depletion  

NASA Astrophysics Data System (ADS)

The intensity fluctuations of a three-level laser are known to drop below shot noise in the presence of depletion of the ground state. We study the fluctuations of the laser output as a function of the parameter ?, defined as the fraction of atoms needed for the laser to operate. For a sufficiently small number of active atoms, the value of ?, and thereby the ground-state depletion, can be appreciable even for modest pumping. This suggests that the intensity fluctuations in the laser output would decrease below shot noise as the number of active atoms is reduced. A microscopic approach that uses a quantum-trajectory method and a macroscopic approach using semiclassical rate equations both show, however, that rather than decreasing, the intensity fluctuations actually increase with ?. We find that the fluctuations of the output are determined by the dependence of the cycle time of the atoms on the number of photons in the laser mode.

Visser, J.; Nienhuis, G.; Dutra, S. M.; van Exter, M. P.; Woerdman, J. P.

2002-06-01

316

Development of a frequency doubled high powered laser diode end-pumped Nd:YVO?/LBO laser  

E-print Network

to determine the temperature distribution within the laser media. Experiments are performed to characterize the laser diode spectral output and laser crystal response to the pump radiation. Finally, the thesis presents a simple technique to image infrared...

Barr, Aaron Maxwell

2012-06-07

317

551 nm Generation by sum-frequency mixing of intracavity pumped Nd:YAG laser  

NASA Astrophysics Data System (ADS)

We present for the first time a Nd:YAG laser emitting at 1319 nm intracavity pumped by a 946 nm diode-pumped Nd:YAG laser. A 809 nm laser diode is used to pump the first Nd:YAG crystal emitting at 946 nm, and the second Nd:YAG laser emitting at 1319 nm intracavity pumped at 946 nm. Intracavity sumfrequency mixing at 946 and 1319 nm was then realized in a LBO crystal to reach the yellow range. We obtained a continuous-wave output power of 158 mW at 551 nm with a pump laser diode emitting 18.7 W at 809 nm.

Dong, Y.; Li, S. T.; Zhang, X. H.

2012-02-01

318

Broadband OPCPA pumped by ultra-narrowband gaseous iodine laser  

NASA Astrophysics Data System (ADS)

Amplification of femtosecond pulses using an ultra-narrowband gaseous pulse laser was demonstrated for the first time. A single-shot sub-nanosecond iodine photodissociation laser with a bandwidth of 20 pm was used as a driver in an allstage OPCPA. An externally triggerable OPO tuned to laser line of 1315.24 nm was used in the front end of the iodine laser. Frequency tripled beam at 438 nm was used to pump parametric amplifiers, LBO and KDP crystals. The signal pulses from a Ti:sapphire laser at the central wavelength of 800 nm with a bandwidth of 70 nm (FWHM) were stretched from 12.5 fs to 250 ps and amplified by a factor of 2×108. The amplified pulses of typical bandwidth of 50 nm were compressed down to 27 fs. The output power of 0.5 TW was achieved. An optimized amplifier chain and addition of a third nonlinear crystal would enable to generate femtosecond pulses of several terawatts. The broadband pulses at 800 nm central wavelength were amplified in the KDP crystal for the first time, due to the suitable wavelength of the pump pulses. Availability of large aperture KDP crystals promises the generation of petawatt beam at kJ iodine laser facilities.

Novák, O.; Tur?i?ová, H.; Divoký, M.; Smrž, M.; Huynh, J.; Straka, P.

2012-02-01

319

High-power Er:YAG laser at 1646nm pumped by an Er,Yb fiber laser  

Microsoft Academic Search

In this paper we describe an Er:YAG laser pumped by a tunable, cladding-pumped Er,Yb fiber laser and discuss factors affecting the laser performance. Crystals with different Er 3+-concentrations in the range 0.5% to 4 at% and with crystal lengths selected for ~95% absorption of the pump light at 1532nm were used, and the laser performance was investigated for a range

Peter Jander; Jayanta K. Sahu; W. Andrew Clarkson

320

Future directions in 980-nm pump lasers: submarine deployment to low-cost watt-class terrestrial pumps  

NASA Astrophysics Data System (ADS)

The demands of global bandwidth and distribution are rising rapidly as Internet usage grows. This fundamentally means that more photons are flowing within optical cables. While transmitting sources launches some optical power, the majority of the optical power that is present within modern telecommunication systems originates from optical amplifiers. In addition, modern optical amplifiers offer flat optical gain over broad wavelength bands, thus making possible dense wavelength de-multiplexing (DWDM) systems. Optical amplifier performance, and by extension the performance of the laser pumps that drive them, is central to the future growth of both optical transmission and distribution systems. Erbium-doped amplifiers currently dominate optical amplifier usage. These amplifiers absorb pump light at 980 nm and/or 1480 nm, and achieve gain at wavelengths around 1550 nm. 980 nm pumps achieve better noise figures and are therefore used for the amplification of small signals. Due to the quantum defect, 1480 nm lasers deliver more signal photon per incident photon. In addition, 1480 nm lasers are less expensive than 980 nm lasers. Thus, 1480 nm pump lasers are used for amplification in situations where noise is not critical. The combination of these traits leads to the situation where many amplifiers contain 980 nm lasers to pump the input section of the Er- doped fiber with 1480 nm lasers being used to pump the latter section of Er fiber. This can be thought of as using 980 nm lasers to power an optical pre-amplifier with the power amplification function being pump with 1480 nm radiation. This paper will focus on 980 nm pump lasers and the impact that advances in 980 nm pump technology will have on optical amplification systems. Currently, 980 nm technology is rapidly advancing in two areas, power and reliability. Improving reliability is becoming increasingly important as amplifiers move towards employing more pump lasers and using these pump lasers without redundancy. Since the failure rate allowable for an amplifier is not a function of the number of pumps employed in the amplifier, the allowable failure rate of an individual pump laser is decreasing for next-generation amplifiers. This will lead to specifications for terrestrial pumps well below 1000 FIT, and may lead to the case where high power amplifiers need laser pump reliability to approach 100 FIT. In addition, 980 nm laser diodes are now being deployed in submarine systems where failure rates lower than 100 FIT are commonly specified. It is obvious that both terrestrial and submarine markets are pushing allowable failure rates for pumps for optical amplifiers to continually decrease. A second push for improvement is in the output power of 980 nm pump modules. There exist a number of motivations for increasing the output power of pump lasers. First, each additional channel in a DWDM system requires additional power. To first order, a doubling in channel count implies a doubling in pump power. Second, larger amplifiers require multiple pumps. Higher output power from pump modules allows for fewer pumps, less complicated control systems and smaller size amplifiers. The discussion of this paper will focus on how current development progress of 980 nm laser diodes addresses these issues: better reliability and higher output powers.

Gulgazov, Vadim N.; Jackson, Gordon S.; Lascola, Kevin M.; Major, Jo S.; Parke, Ross; Richard, Tim; Rossin, Victor V.; Zhang, Kai

1999-09-01

321

Laser demonstration and performance characterization of optically pumped Alkali Laser systems  

NASA Astrophysics Data System (ADS)

Diode Pumped Alkali Lasers (DPALs) offer a promising approach for high power lasers in military applications that will not suffer from the long logistical trails of chemical lasers or the thermal management issues of diode pumped solid state lasers. This research focuses on characterizing a DPAL-type system to gain a better understanding of using this type of laser as a directed energy weapon. A rubidium laser operating at 795 nm is optically pumped by a pulsed titanium sapphire laser to investigate the dynamics of DPALs at pump intensities between 1.3 and 45 kW/cm2. Linear scaling as high as 32 times threshold is observed, with no evidence of second order kinetics. Comparison of laser characteristics with a quasi-two level analytic model suggests performance near the ideal steady-state limit, disregarding the mode mis-match. Additionally, the peak power scales linearly as high as 1 kW, suggesting aperture scaling to a few cm2 is sufficient to achieve tactical level laser powers. The temporal dynamics of the 100 ns pump and rubidium laser pulses are presented, and the continually evolving laser efficiency provides insight into the bottlenecking of the rubidium atoms in the 2P3/2 state. Lastly, multiple excited states of rubidium and cesium were accessed through two photon absorption in the red, yielding a blue and an IR photon through amplified stimulated emission. Threshold is modest at 0.3 mJ/pulse, and slope efficiencies increase dramatically with alkali concentrations and peak at 0.4%, with considerable opportunity for improvement. This versatile system might find applications for IR countermeasures or underwater communications.

Sulham, Clifford V.

322

Polarization features of optically pumped CdS nanowire lasers  

NASA Astrophysics Data System (ADS)

High quality CdS nanowires suspended in air were optically pumped both below and above the lasing threshold. The polarization of the pump laser was varied while emission out of the end facet of the nanowire was monitored in a ‘head-on’ measurement geometry. Highest pump-efficiency and most efficient absorption of the pump radiation are demonstrated for an incident electric field being polarized parallel to the nanowire axis. This polarization dependence, which was observed both above the lasing threshold and in the regime of amplified spontaneous emission, is caused by an enhanced absorption for parallel polarized optical pumping. Measured Stokes parameters of the nanowire emission reveal that due to the onset of lasing the degree of polarization rapidly increases from approximately 15 to 85%. Both Stokes parameters and degree of polarization of the nanowire lasing emission are independent of the excitation polarization. The transversal lasing mode is therefore not notably affected by the polarization of the pumping beam, although the supply with optical gain is significantly enhanced for an excitation polarization parallel to the nanowire axis.

Röder, Robert; Ploss, Daniel; Kriesch, Arian; Buschlinger, Robert; Geburt, Sebastian; Peschel, Ulf; Ronning, Carsten

2014-10-01

323

Pulsed submillimeter laser pumped by CO/sub 2/ laser radiation  

SciTech Connect

A study was made of the energy and time characteristics of a submillimeter laser pumped by CO/sub 2/ laser radiation. The optimal stimulated emission conditions were found for vibrational--rotational transitions in the CH/sub 3/I and CD/sub 3/I molecules.

Manita, O.F.

1980-03-01

324

Highly Efficient Operation of Tm:fiber Laser Pumped Ho:YLF Laser  

NASA Technical Reports Server (NTRS)

A 19 W, TEM(sub 00) mode, Ho:YLF laser pumped by continuous wave Tm:fiber laser has been demonstrated at the room temperature. The slope efficiency and optical-to-optical efficiency are 65% and 55%, respectively.

Bai, Yingxin; Petros, M.; Yu, Jirong; Petzar, Paul; Trieu, Bo; Chen, Sam; Lee, Hyung; Singh, U.

2006-01-01

325

Instabilities in a laser-diode-pumped microchip solid-state laser with feedback  

NASA Astrophysics Data System (ADS)

Random chaotic relaxation oscillation burst generations have been observed in laser-diode-pumped microchip multimode lasers coupled to a single-mode optical fiber. Dynamical characterizations have been carried out by the singular value decomposition method and the joint time-frequency analysis, and the observed instability has been identified to be a random switching between stable and chaotic operation.

Otsuka, K.; Ko, J.-Y.; Chern, J.-L.; Ohki, K.; Utsu, H.

1999-11-01

326

Nd:LNA laser optical pumping of He-4 - Application to space magnetometers  

NASA Technical Reports Server (NTRS)

Results obtained from laser pumping in a helium magnetometer sensor, using a tunable Nd:LNA laser pumped with a high-power diode laser, are reported. It is shown that it was possible to observe both the Hanle signals and the n = 0, p = 1 parametric resonance by monitoring the pumping radiation passing through the cell. As the diode laser-pumped Nd:LNA laser was tuned through the D0, D1, and D2 transitions, three distinct resonance signals were produced. A comparison of the slope of lamp-pumped signals and laser-pumped D1 signals showed that, under otherwise identical conditions, the slope of the D1 laser signal was 45 times greater than the lamp-pumped signal.

Slocum, R. E.; Schearer, L. D.; Tin, P.; Marquedant, R.

1988-01-01

327

Low-cost, single-mode diode-pumped Cr:Colquiriite lasers  

E-print Network

We present three Cr[superscript 3+]:Colquiriite lasers as low-cost alternatives to Ti:Sapphire laser technology. Single-mode laser diodes, which cost only $150 each, were used as pump sources. In cw operation, with ~520 ...

Demirbas, Umit

328

Luminescent light source for laser pumping and laser system containing same  

DOEpatents

The invention relates to a pumping lamp for use with lasers comprising a porous substrate loaded with a component capable of emitting light upon interaction of the component with exciting radiation and a source of exciting radiation. Preferably, the pumping lamp comprises a source of exciting radiation, such as an electron beam, and an aerogel or xerogel substrate loaded with a component capable of interacting with the exciting radiation, e.g., a phosphor, to produce light, e.g., visible light, of a suitable band width and of a sufficient intensity to generate a laser beam from a laser material.

Hamil, Roy A. (Tijeras, NM); Ashley, Carol S. (Albuquerque, NM); Brinker, C. Jeffrey (Albuquerque, NM); Reed, Scott (Albuquerque, NM); Walko, Robert J. (Albuquerque, NM)

1994-01-01

329

Dual-pump CARS temperature and major species concentration measurements in counter-flow methane flames using narrowband pump and broadband Stokes lasers  

SciTech Connect

Dual-pump coherent anti-Stokes Raman scattering (CARS) is used to measure temperature and species profiles in representative non-premixed and partially-premixed CH{sub 4}/O{sub 2}/N{sub 2} flames. A new laser system has been developed to generate a tunable single-frequency beam for the second pump beam in the dual-pump N{sub 2}-CO{sub 2} CARS process. The second harmonic output ({proportional_to}532 nm) from an injection-seeded Nd:YAG laser is used as one of the narrowband pump beams. The second single-longitudinal-mode pump beam centered near 561 nm is generated using an injection-seeded optical parametric oscillator, consisting of two non-linear {beta}-BBO crystals, pumped using the third harmonic output ({proportional_to}355 nm) of the same Nd:YAG laser. A broadband dye laser (BBDL), pumped using the second harmonic output of an unseeded Nd:YAG laser, is employed to produce the Stokes beam centered near 607 nm with full-width-at-half-maximum of {proportional_to}250 cm{sup -1}. The three beams are focused between two opposing nozzles of a counter-flow burner facility to measure temperature and major species concentrations in a variety of CH{sub 4}/O{sub 2}/N{sub 2} non-premixed and partially-premixed flames stabilized at a global strain rate of 20 s{sup -1} at atmospheric-pressure. For the non-premixed flames, excellent agreement is observed between the measured profiles of temperature and CO{sub 2}/N{sub 2} concentration ratios with those calculated using an opposed-flow flame code with detailed chemistry and molecular transport submodels. For partially-premixed flames, with the rich side premixing level beyond the stable premixed flame limit, the calculations overestimate the distance between the premixed and the non-premixed flamefronts. Consequently, the calculated temperatures near the rich, premixed flame are higher than those measured. Accurate prediction of the distance between the premixed and the non-premixed flames provides an interesting challenge for future computations. (author)

Thariyan, Mathew P.; Ananthanarayanan, Vijaykumar; Bhuiyan, Aizaz H.; Naik, Sameer V.; Gore, Jay P.; Lucht, Robert P. [School of Mechanical Engineering, Purdue University, West Lafayette, IN 47907 (United States)

2010-07-15

330

Collagen Remodeling After 585-nm Pulsed Dye Laser Irradiation: An Ultrasonographic Analysis  

E-print Network

after treatment. Ultrasound images were obtained with the Episcan I-100 (Longport Inc., Swarthmore, PACollagen Remodeling After 585-nm Pulsed Dye Laser Irradiation: An Ultrasonographic Analysis BRENT R. MOODY, MD,n JOHN E. MCCARTHY, PHD,w AND GEORGE J. HRUZA, MDn n Laser and Dermatologic Surgery Center

McCarthy, John E.

331

Stark effect applicable to optically pumped far-infrared laser  

NASA Technical Reports Server (NTRS)

Absorption measurements at CO2 laser frequencies were carried out as a function of Stark fields and CH3OH gas pressures to assess the effect of low electric field Stark tuning on methanol absorption at the P(12) 9.4 micron CO2 laser line, in a continuing search for coherent emitters at submillimeter wavelengths (far infrared). The line center absorption coefficient is found to increase five-fold with a 2.3 kV/cm Stark field at the 220 mtorr methanol pressure optimal for methanol far infrared lasing. The low electric field Stark tuning encourages efforts to enhance the pumping efficiency of a methanol far infrared laser at its normal optimum operating pressure, and suggests that significant Stark field induced frequency modulation of the far IR laser output is feasible.

Claspy, P. C.; Koo, K. P.

1976-01-01

332

Advances in solid state laser technology for space and medical applications  

NASA Technical Reports Server (NTRS)

Recent developments in laser technology and their potential for medical applications are discussed. Gas discharge lasers, dye lasers, excimer lasers, Nd:YAG lasers, HF and DF lasers, and other commonly used lasers are briefly addressed. Emerging laser technology is examined, including diode-pumped lasers and other solid state lasers.

Byvik, C. E.; Buoncristiani, A. M.

1988-01-01

333

Narrow line diode laser stacks for DPAL pumping  

NASA Astrophysics Data System (ADS)

Diode pumped alkali metal vapor lasers (DPALs) offer the promise of scalability to very high average power levels while maintaining excellent beam quality, making them an attractive candidate for future defense applications. A variety of gain media are used and each requires a different pump wavelength: near 852nm for cesium, 780nm for rubidium, 766nm for potassium, and 670nm for lithium atoms. The biggest challenge in pumping these materials efficiently is the narrow gain media absorption band of approximately 0.01nm. Typical high power diode lasers achieve spectral widths around 3nm (FWHM) in the near infrared spectrum. With state of the art locking techniques, either internal to the cavity or externally mounted gratings, the spectral width can typically be reduced to 0.5nm to 1nm for kW-class, high power stacks. More narrow spectral width has been achieved at lower power levels. The diode's inherent wavelength drift over operating temperature and output power is largely, but not completely, eliminated. However, standard locking techniques cannot achieve the required accuracy on the location of the spectral output or the spectral width for efficient DPAL pumping. Actively cooled diode laser stacks with continuous wave output power of up to 100W per 10mm bar at 780nm optimized for rubidium pumping will be presented. Custom designed external volume holographic gratings (VHGs) in conjunction with optimized chip material are used to narrow and stabilize the optical spectrum. Temperature tuning on a per-bar-level is used to overlap up to fifteen individual bar spectra into one narrow peak. At the same time, this tuning capability can be used to adjust the pump wavelength to match the absorption band of the active medium. A spectral width of <0.1nm for the entire stack is achieved at <1kW optical output power. Tuning of the peak wavelength is demonstrated for up to 0.15nm. The technology can easily be adapted to other diode laser wavelengths to pump different materials.

Koenning, Tobias; Irwin, David; Stapleton, Dean; Pandey, Rajiv; Guiney, Tina; Patterson, Steve

2014-02-01

334

High-Reliability Pump Module for Non-Planar Ring Oscillator Laser  

NASA Technical Reports Server (NTRS)

We propose and have demonstrated a prototype high-reliability pump module for pumping a Non-Planar Ring Oscillator (NPRO) laser suitable for space missions. The pump module consists of multiple fiber-coupled single-mode laser diodes and a fiber array micro-lens array based fiber combiner. The reported Single-Mode laser diode combiner laser pump module (LPM) provides a higher normalized brightness at the combined beam than multimode laser diode based LPMs. A higher brightness from the pump source is essential for efficient NPRO laser pumping and leads to higher reliability because higher efficiency requires a lower operating power for the laser diodes, which in turn increases the reliability and lifetime of the laser diodes. Single-mode laser diodes with Fiber Bragg Grating (FBG) stabilized wavelength permit the pump module to be operated without a thermal electric cooler (TEC) and this further improves the overall reliability of the pump module. The single-mode laser diode LPM is scalable in terms of the number of pump diodes and is capable of combining hundreds of fiber-coupled laser diodes. In the proof-of-concept demonstration, an e-beam written diffractive micro lens array, a custom fiber array, commercial 808nm single mode laser diodes, and a custom NPRO laser head are used. The reliability of the proposed LPM is discussed.

Liu, Duncan T.; Qiu, Yueming; Wilson, Daniel W.; Dubovitsky, Serge; Forouhar, Siamak

2007-01-01

335

High-reliability pump module for non-planar ring oscillator laser  

NASA Astrophysics Data System (ADS)

We propose and have demonstrated a prototype high-reliability pump module for pumping a Non-Planar Ring Oscillator (NPRO) laser suitable for space missions. The pump module consists of multiple fiber-coupled single-mode laser diodes and a fiber array micro-lens array based fiber combiner. The reported Single-Mode laser diode combiner laser pump module (LPM) provides a higher normalized brightness at the combined beam than multimode laser diode based LPMs. A higher brightness from the pump source is essential for efficient NPRO laser pumping and leads to higher reliability because higher efficiency requires a lower operating power for the laser diodes, which in turn increases the reliability and lifetime of the laser diodes. Single-mode laser diodes with Fiber Bragg Grating (FBG) stabilized wavelength permit the pump module to be operated without a thermal electric cooler (TEC) and this further improves the overall reliability of the pump module. The single-mode laser diode LPM is scalable in terms of the number of pump diodes and is capable of combining hundreds of fiber-coupled laser diodes. In the proof-of-concept demonstration, an e-beam written diffractive micro lens array, a custom fiber array, commercial 808nm single mode laser diodes, and a custom NPRO laser head are used. The reliability of the proposed LPM is discussed.

Liu, Duncan T.; Qiu, Yueming; Wilson, Daniel W.; Dubovitsky, Serge; Forouhar, Siamak

2007-09-01

336

LASERS: Iodine laser pumped by light from a shock front created by detonating an explosive  

Microsoft Academic Search

The results are presented of investigations, performed in 1965-1966, of a pulsed photodissociation iodine laser utilizing CF3I and C3F7I molecules and pumped by light from a shock front created by detonating an explosive charge. Such lasers were found to possess a unique combination of high output energy and high pulse power. Two types of laser were studied. In one of

V. P. Arzhanov; Boris L. Borovich; V. S. Zuev; V. M. Kazanskii; V. A. Katulin; G. A. Kirillov; S. B. Kormer; Yu V. Kuratov; A. I. Kuryapin; O. Yu Nosach; M. V. Sinitsyn; Yu Yu Stoilov

1992-01-01

337

Efficient holmium:yttrium lithium fluoride laser longitudinally pumped by a semiconductor laser array  

NASA Technical Reports Server (NTRS)

Optical pumping of a holmium:yttrium lithium floride (Ho:YLF) crystal with a 790-nm continuous-wave diode-laser array has generated 56 mW of 2.1-micron laser radiation with an optical-to-optical conversion slope efficiency of 33 percent while the crystal temperature is held at 77 K. The lasing threshold occurs at 7 mW of input power, and laser operation continues up to a crystal temperature of 124 K.

Hemmati, H.

1987-01-01

338

Dual-Wavelength Internal-Optically-Pumped Semiconductor Laser Diodes  

NASA Astrophysics Data System (ADS)

Dual-wavelength laser sources have various existing and potential applications in wavelength division multiplexing, differential techniques in spectroscopy for chemical sensing, multiple-wavelength interferometry, terahertz-wave generation, microelectromechanical systems, and microfluidic lab-on-chip systems. In the drive for ever smaller and increasingly mobile electronic devices, dual-wavelength coherent light output from a single semiconductor laser diode would enable further advances and deployment of these technologies. The output of conventional laser diodes is however limited to a single wavelength band with a few subsequent lasing modes depending on the device design. This thesis investigates a novel semiconductor laser device design with a single cavity waveguide capable of dual-wavelength laser output with large spectral separation. The novel dual-wavelength semiconductor laser diode uses two shorter- and longer-wavelength active regions that have separate electron and hole quasi-Fermi energy levels and carrier distributions. The shorter-wavelength active region is based on electrical injection as in conventional laser diodes, and the longer-wavelength active region is then pumped optically by the internal optical field of the shorter-wavelength laser mode, resulting in stable dual-wavelength laser emission at two different wavelengths quite far apart. Different designs of the device are studied using a theoretical model developed in this work to describe the internal optical pumping scheme. The carrier transport and separation of the quasi-Fermi distributions are then modeled using a software package that solves Poisson's equation and the continuity equations to simulate semiconductor devices. Three different designs are grown using molecular beam epitaxy, and broad-area-contact laser diodes are processed using conventional methods. The modeling and experimental results of the first generation design indicate that the optical confinement factor of the longer-wavelength active region is a critical element in realizing dual-wavelength laser output. The modeling predicts lower laser thresholds for the second and third generation designs; however, the experimental results of the second and third generation devices confirm challenges related to the epitaxial growth of the structures in eventually demonstrating dual-wavelength laser output.

Green, Benjamin

339

Threshold kinetics of a solar-simulator-pumped iodine laser  

Microsoft Academic Search

A model of the chemical kinetics of the n-C3F7I solar-simulator-pumped iodine laser is utilized to study the major kinetic processes associated with the threshold behavior of this experimental system. Excited-state diffusion to the cell wall is the dominant limiting factor below 5 torr. Excited-state diffusion to the cell wall is the dominant limiting factor below 5 torr. Excited-state recombination with

J. W. Wilson; Y. Lee; W. R. Weaver; D. H. Humes; J. H. Lee

1984-01-01

340

Thin-Film Evaporative Cooling for Side-Pumped Laser  

NASA Technical Reports Server (NTRS)

A system and method are provided for cooling a crystal rod of a side-pumped laser. A transparent housing receives the crystal rod therethrough so that an annular gap is defined between the housing and the radial surface of the crystal rod. A fluid coolant is injected into the annular gap such the annular gap is partially filled with the fluid coolant while the radial surface of the crystal rod is wetted as a thin film all along the axial length thereof.

Stewart, Brian K. (Inventor)

2010-01-01

341

Direct solar-pumped iodine laser amplifier. Semiannual progress report, 1 March30 September 1987  

Microsoft Academic Search

This semiannual progress report covers the period from March 1, 1987 to September 30, 1987 under NASA grant NAG1-441 entitled Direct solar-pumped iodine laser amplifier. During this period Nd:YAG and Nd:Cr:GSGG crystals have been tested for the solar-simulator pumped cw laser, and loss mechanisms of the laser output power in a flashlamp-pumped iodine laser also have been identified theoretically. It

Han

1987-01-01

342

Scaling CW diode-end-pumped Nd:YAG lasers to high average powers  

Microsoft Academic Search

The authors analyze the scaling limits of diode-end-pumped Nd:YAG lasers imposed by pumping geometry, thermal distortion, birefringence, and fracture. A scalable 15-W output power diode-end-pumped laser which achieves a 60% slope efficiency is demonstrated. Thermal distortion in this laser is reduced from 2.6 waves to less than 0.15 waves with an aspheric laser rod. Depolarization is reduced by 40 times

Steve C. Tidwell; Jonathan F. Seamans; Mark S. Bowers; Ananda K. Cousins

1992-01-01

343

A microwave-pumped slab CO{sub 2} laser  

SciTech Connect

The radiation parameters of a diffusion-cooled compact slab CO{sub 2} laser pumped by microwave discharge at a frequency of 2.45 GHz are studied. A magnetron from a domestic microwave oven is used as the pump source. An average output power of 25 W and an efficiency of {approx}13% are obtained at a wavelength 10.6 {mu}m. A peak output power of 580 W is achieved for 20-{mu}s pulses emitted at a pulse repetition rate of 400 Hz. The dependence of parameters of the CO{sub 2} laser on the input pulse power in the range 0.8-8 kW, the composition and pressure of the working mixture and the pump pulse duration and repetition rate are studied experimentally. Optimal relations between these parameters are determined for the given design of the laser. (special issue devoted to the 25th anniversary of the a.m. prokhorov general physics institute)

Mineev, A P; Nefedov, S M; Pashinin, P P [A.M. Prokhorov General Physics Institute, Russian Academy of Sciences, Moscow (Russian Federation)

2007-10-31

344

Surgical treatment of rhinophyma using carbon dioxide (CO2) laser and pulsed dye laser (PDL).  

PubMed

Rhinophyma is a slowly progressive, benign dermatological disorder of the nose. The most widely accepted theory is that rhinophyma is the end stage of chronic rosacea. The primary reason for its excision is cosmetic deformity. Many treatment modalities have been described, including CO(2) laser. This method provides a very dry surgical field, which allows the sculpting of the hypertrophic areas. Pulsed dye laser (PDL) is a safe and effective treatment, resulting in a significant improvement in erythema, telangiectases, symptoms and quality of life. We report the case of a 63-year-old Caucasian man with a 2-year history of rapid progression rhinophyma. The patient was submitted to five CO(2) laser sessions, followed by three PDL sessions. Favourable re-epithelization of the surfaces treated with CO(2) laser was achieved within a very short period of time. PDL post-treatment purpura lasted a medium of 12 days. After 12 months of follow-up the patient remains without evidence of relapse. To our knowledge, this is the first case described of treatment using a combination of the CO(2) laser and PDL. PMID:20331343

Moreira, Ana; Leite, Inês; Guedes, Rita; Baptista, Armando; Mota, Gioconda

2010-04-01

345

Diffusive and convective dye replenishment in optofluidic light sources  

NASA Astrophysics Data System (ADS)

Optofluidic dye lasers have recently attracted much interest as potentially efficient light sources for integration on lab-on-a-chip micro-systems. However, dye bleaching resulting in limited life-time could limit the applications of such devices in lab-on-a-chip technology. Typically, the problem of dye bleaching is addressed by employing a continuous convective flow of liquid-dissolved dye molecules, compensating the bleaching caused by the external optical pump. In previously reported optofluidic light sources the required convective dye replenishing flow has been achieved by external fluid handling apparatus (syringe pumps), on-chip microfluidic pumps, or by means of capillary effect. We have investigated the bleaching dynamics that occur in optofluidic light sources where a liquid laser dye in a micro-fluidic channel is locally bleached due to optical pumping. A simple one-dimensional diffusion model is used to explore the characteristic evolution of the local un-bleached dye concentration in the optically pumped or bleached volume of the device. In the absence of convective flow, the decay of the local dye concentration in the optically pumped volume is governed by the diffusion rate and the resulting lifetime of the device is mainly limited by the capacity of the fluidic reservoirs. Generic microfluidic platforms typically allow for device layouts with a large volume ratio between the fluidic reservoir and the region being optically pumped. These conclusions drawn from the simple model are supported by basic experiments. Our investigations reveal the possibility that such optofluidic dye laser devices may potentially be operated for days by diffusion without the need for a convective flow. Relying on diffusion rather than convection to generate the necessary dye replenishment significantly simplifies optofluidic dye laser device layouts, omitting the need for cumbersome and costly external fluidic handling or on-chip microfluidic pumping devices.

Gersborg-Hansen, Morten; Mortensen, Niels Asger; Kristensen, Anders

2007-09-01

346

Sensing of DNA conformation based on change in FRET efficiency between laser dyes  

E-print Network

This communication reports the effect of DNA conformation on fluorescence resonance energy transfer (FRET) efficiency between two laser dyes in layer by layer (LbL) self assembled film. The dyes Acraflavine and Rhodamine B were attached onto the negative phosphate backbones of DNA in LbL film through electrostatic attraction. Then FRET between these dyes was investigated. Increase in pH or temperature causes the denaturation of DNA followed by coil formation of single stranded DNA. As a result the FRET efficiency also changed along with it. These observations demonstrated that by observing the change in FRET efficiency between two laser dyes in presence of DNA it is possible to detect the altered DNA conformation in the changed environment.

Dey, Dibyendu; Roy, Arpan Datta; Bhattacharjee, D; Sinha, Sangram; Paul, P K; Chakraborty, Santanu; Hussain, Syed Arshad

2014-01-01

347

High-energy optically pumped iodine laser. I - Kinetics in an optically thick medium  

Microsoft Academic Search

A theoretical description is given of the operation of a high-energy atomic iodine laser pumped by high-intensity broadband radiation, with allowance for nonlinear transport of pump radiation into an optically thick medium. The proposed model determines the temporal and spatial dependences of the various chemical species, gas temperature, pump radiation, and stimulated emission in the laser medium. The model is

J. S. Cohen; O. P. Judd

1984-01-01

348

CW Theory of quasi-three level end-pumped laser oscillators  

Microsoft Academic Search

Equations describing the pump excitation and power extraction of end-pumped quasi-three level CW laser oscillators are derived which are useful in the optimization of such systems. The theory takes into account arbitrarily large ground state depletion due to intense pumping as well as gain saturation due to the extracting laser beam. The presented theory is more general than previously published

Raymond J Beach

1996-01-01

349

Laser rods with undoped, flanged end-caps for end-pumped laser applications  

DOEpatents

A method and apparatus for achieving improved performance in a solid state laser is provided. A flanged, at least partially undoped end-cap is attached to at least one end of a laserable medium. Preferably flanged, undoped end-caps are attached to both ends of the laserable medium. Due to the low scatter requirements for the interface between the end-caps and the laser rod, a non-adhesive method of bonding is utilized such as optical contacting combined with a subsequent heat treatment of the optically contacted composite. The non-bonded end surfaces of the flanged end-caps are coated with laser cavity coatings appropriate for the lasing wavelength of the laser rod. A cooling jacket, sealably coupled to the flanged end-caps, surrounds the entire length of the laserable medium. Radiation from a pump source is focussed by a lens duct and passed through at least one flanged end-cap into the laser rod.

Meissner, Helmuth E. (Pleasanton, CA); Beach, Raymond J. (Livermore, CA); Bibeau, Camille (Danville, CA); Sutton, Steven B. (Manteca, CA); Mitchell, Scott (Tracy, CA); Bass, Isaac (Castro Valley, CA); Honea, Eric (Sunol, CA)

1999-01-01

350

Crystalline fiber Ho3+:YAG laser resonantly pumped by high-spectral-brightness laser diodes  

NASA Astrophysics Data System (ADS)

Recent advances of high power and narrow bandwidth laser diodes emitting at 1.9 ?m open the path to direct diode pumping of Ho3+:YAG lasers. The usual method to pump such laser is to use thulium fiber laser which has an excellent beam quality with high power and narrow bandwidth emission. The draw back of this system is the low efficiency of this fiber laser and the increased overall complexity. In this paper we present first results of resonantly diode pumping of a Ho3+:YAG laser with fiberlike geometry. The fiber coupled diode modules used for pumping in this work (BrightLockTMUltra-500) produce each 25 W at 1.91 ?m with 3 nm linewidth. The fiber has a core diameter of 600 ?m with 0.22 numerical aperture. The Ho3+:YAG crystal has a diameter of 1.2 mm, a length of 60 mm, a doping concentration of 0.75 at.% and is symmetrically pumped by two diode modules from both ends. Total internal reflection on the polished rod barrel allows a high pump intensity along the rod length. The Ho3+:YAG laser cavity is composed of a high reflective flat mirror and a concave output coupler with a radius of curvature of 500 mm. With an output coupler of 50 % we measured a threshold of 11 W. The maximum output power was 11.87 W with a wavelength of 2.09 ?m. The incident power to output power slope efficiency was 0.38 at currently 4 % of internal losses.

Berrou, Antoine; Ibach, Thierry; Schellhorn, Martin; Hu, Wentao; Lammert, Robert; Vaissié, Laurent; Ungar, Jeff; Eichhorn, Marc

2012-03-01

351

SEPARATION OF HISTORICAL DYES USING CAPILLARY ELECTROPHORESIS WITH LASER-INDUCED FLUORESCENCE DETECTION  

Microsoft Academic Search

In this study, the separation properties of alizarin, purpurin, carmine and morin were explored using capillary electrophoresis (CE). A 30 cm capillary (10 µm i.d.) and an applied voltage of 16-20 kV was used to separate the dyes prior to post-column detection in a sheath flow cuvette using laser-induced fluorescence (LIF). Two lasers were used for excitation; a 488 nm argon ion laser and

Douglas M. Goltz; Shokoufeh Ahmadi; Ghodrattolah Absalan; Douglas B. Craig

2012-01-01

352

LASERS: Iodine laser pumped by light from a shock front created by detonating an explosive  

NASA Astrophysics Data System (ADS)

The results are presented of investigations, performed in 1965-1966, of a pulsed photodissociation iodine laser utilizing CF3I and C3F7I molecules and pumped by light from a shock front created by detonating an explosive charge. Such lasers were found to possess a unique combination of high output energy and high pulse power. Two types of laser were studied. In one of them the active medium was pumped by light from a shock wave in xenon, and in the other a shock wave propagated through a mixture of the active medium and a rare gas. The energy characteristics of the second type of laser were found to be considerably higher than those of the first type. The laser pulse radiation enegy reached ~100 J with an average power of ~15 MW.

Arzhanov, V. P.; Borovich, Boris L.; Zuev, V. S.; Kazanski?, V. M.; Katulin, V. A.; Kirillov, G. A.; Kormer, S. B.; Kuratov, Yu V.; Kuryapin, A. I.; Nosach, O. Yu; Sinitsyn, M. V.; Sto?lov, Yu Yu

1992-02-01

353

Gain dynamics of a free-space nitrogen laser pumped by circularly polarized femtosecond laser pulses  

NASA Astrophysics Data System (ADS)

We experimentally demonstrate ultrafast dynamic of generation of a strong 337-nm nitrogen laser by injecting an external seed pulse into a femtosecond laser filament pumped by a circularly polarized laser pulse. In the pump-probe scheme, it is revealed that the population inversion between the excited and ground states of N2 for the free-space 337-nm laser is firstly built up on the timescale of several picoseconds, followed by a relatively slow decay on the timescale of tens of picoseconds, depending on the nitrogen gas pressure. By measuring the intensities of 337-nm signal from nitrogen gas mixed with different concentrations of oxygen gas, it is also found that oxygen molecules have a significant quenching effect on the nitrogen laser signal. Our experimental observations agree with the picture of electron-impact excitation.

Yao, Jinping; Xie, Hongqiang; Zeng, Bin; Chu, Wei; Li, Guihua; Ni, Jielei; Zhang, Haisu; Jing, Chenrui; Zhang, Chaojin; Xu, Huailiang; Cheng, Ya; Xu, Zhizhan

2014-08-01

354

Development of lasers optimized for pumping Ti:Al2O3 lasers  

NASA Technical Reports Server (NTRS)

Laboratory demonstrations that were completed included: (1) an all-solid-state, broadly tunable, single-frequency, Ti:Al2O3 master oscillator, and (2) a technique for obtaining 'long' (nominally 100- to 200-ns FWHM) laser pulses from a Q-switched, Nd oscillator at energy levels commensurate with straightforward amplification to the joule level. A diode-laser-pumped, Nd:YLF laser with intracavity SHG was designed, constructed, and evaluated. With this laser greater than 0.9 W of CW, output power at 523.5 nm with 10 W of diode-laser pump power delivered to the Nd:YLF crystal was obtained. With this laser as a pump source, for the first time, to our knowledge, an all solid-state, single frequency, Ti:Al203 laser with sufficient output power to injection seed a high-energy oscillator over a 20-nm bandwidth was demonstrated. The pulsed laser work succeeded in demonstrating pulse-stretching in a Q-switched Nd:YAG oscillator. Pulse energies greater than 50-mJ were obtained in pulses with 100- to 200-ns pulsewidths (FWHM).

Rines, Glen A.; Schwarz, Richard A.

1994-01-01

355

Effect of pump wavelength on self-induced laser line sweeping in Yb-doped fiber laser  

NASA Astrophysics Data System (ADS)

We have characterized ytterbium-doped fiber laser and described in detail the effect of pump wavelength on self-induced laser line sweeping (SLLS). SLLS is a transient laser regime manifested by a relatively slow laser line shifting and usually observed in the near of pump laser threshold. The fiber laser under consideration is cladding-pumped by a temperature stabilized multimode laser diode (LD) at about 976 nm. The output wavelength of the diode is tunable by changing the diode temperature and current through the diode. The cavity of the laser is formed by perpendicularly cleaved fiber ends. Using this laser layout we made detailed study of sweeping dependences on pump wavelength by adjustment of the LD current and LD case temperature. The laser manifested laser line sweeping within the range of 5-7 nm on a wide span of pump laser diode power and temperature: 15-45°C LD temperature scale and pump range reaching to more than twice the amount of excess over threshold. We performed the measurement of the laser line sweeping span, period and rate as the dependence of pump wavelength.

Navratil, P.; Peterka, P.; Kubecek, V.

2013-05-01

356

Rapid prototyping of a micro pump with laser micromachining  

NASA Astrophysics Data System (ADS)

A microelectrohydrodynamic (EHD) injection pump has been developed using laser micromachining technoogy. Two desings have been fabricated, tested, and evaluated. The first design has two silicon pieces with KOH-etched wells which are stacked on the tpo of each other. The wells are etched on one side of the wafer and gold is deposited on the other side to serve as the pump electrodes. A Nd:YAG laser is used to drill an array of circular holes in the well region of both silicon parts. This creates a grid distribution with a square pattern. Next the well regions of the silicon parts are aligned, and the parts are bonded together using a Staystik thermoplastic. The pump unit is then mounted into a ceramic package with a large hole drilled in the bottom of the package to permit fluid flow. Aluminum ribbon wire bonds are used to connect the pump electrodes to the package leads. Isolation of metallization and wires is achieved by filling the package well and coating the wires with polyimide. When a voltage is applied at the electrodes, ions are injected into the working fluid, such as an organic solvent, thus inducing flow. The second design has the silicon parts oriented 'back-to-back' and bonded together with Stayform. A 'back-to-back' design will decrease the grid distance so that a smaller voltage is required for pumping. Preliminary results have demonstrated that this micropump can achieve a pressure head of about 287 Pa with an applied voltage of 120 Volt.

Wong, C. Channy; Chu, Dahwey; Liu, Sally L.; Tuck, Melanie R.; Mahmud, Zahid; Amatucci, Vincent A.

1995-09-01

357

Optimization of electron-beam pumped excimer laser  

NASA Astrophysics Data System (ADS)

The output energy of an electron-beam pumped xenon flouride laser has been enhanced by optimizing certain electron-gun and gas-mix parameters. The optimized e-gun parameters include anode-cathode spacing, magnetic field strength, and cathode voltage. The optimized laser gas parameters include NF3 concentration, Xe concentration, and total pressure. The shortest anode-cathode spacing (9 cm), the strongest magnetic guide field (1600 Gauss), and the highest cathode voltage (375 kV) gave the highest laser output. The optimum gas concentrations were 0.05 percent NF3, 0.3 percent Xe, with Ne added to bring the total gas pressure to 60 psia. The energy degraded by 2 percent per shot with this gas mix.

Lowum, T. F.; Swecker, J. L.

358

A microporous glass-polymer composite as a new material for solid-state dye lasers: II. Lasing properties  

SciTech Connect

The conversion efficiency and service life of the laser elements based on a polymer-filled microporous glass (PFMPG) composite doped with organic dyes are studied. It is shown that both the conversion efficiency and the service life of the laser elements achieve the values obtained for the same dyes in bulk polymer elements. Good lasing characteristics of the elements studied are advantageously combined with the high mechanical strength and high laser damage resistance and excellent thermooptical properties of the PFMPG composite. (lasers)

Aldag, H R; Pacheco, D P [Physical Sciences Inc., 20 New England Business Center, Andover (United States); Dolotov, S M; Ponomarenko, E P; Reznichenko, A V ['Alfa-Akonis' Research and Devices Enterprise, Dolgoprudnyi, Moscow region (Russian Federation); Koldunov, M F ['Optronika' R and D Enterprise, Dolgoprudnyi, Moscow region (Russian Federation); Kravchenko, Ya V; Manenkov, Aleksandr A [A.M. Prokhorov General Physics Institute, Russian Academy of Sciences, Moscow (Russian Federation); Roskova, G P; Tsekhomskaya, T S [I.V. Grebenshchikov Institute of Silicate Chemistry, Russian Academy of Sciences, St.Petersburg (Russian Federation)

2000-12-31

359

Polarisation of a spin- {1}/{2} ?-NMR probe 11Be using collinear laser optical pumping  

NASA Astrophysics Data System (ADS)

Spin {1}/{2} probes have special importance in the field of NMR, since they have no electric quadrupole moment and are thus pure magnetic sensors. The absence of quadrupolar splittings greatly simplifies the NMR frequency spectrum. That the muon is spin {1}/{2} is one of the reasons it has become so useful as a magnetic probe. Until now there has been no spin {1}/{2} probe suitable for beta-detected NMR. Such a probe would be particularly useful in complex materials, which are in general non-cubic. In this paper we describe the development of a low energy beam of spin-polarised 11Be, which is the lightest spin {1}/{2} isotope suitable for ?-NMR. The intensity of the 11Be+ beam-generated by a laser ionisation source-is about 106/s. The 11Be nuclei are polarised by collinear laser optical pumping with an externally frequency doubled dye laser tuned to the 2S- 2P transition of 11Be+ at 313 nm.

Levy, C. D. P.; Pearson, M. R.; Morris, G. D.; Lassen, J.; Chow, K. H.; Hossain, M. D.; Kiefl, R. F.; Labbé, R.; MacFarlane, W. A.; Parolin, T. J.; Root, L.; Saadaoui, H.; Smadella, M.; Wang, D.

2009-04-01

360

A blackbody-pumped CO2-N2 transfer laser  

NASA Technical Reports Server (NTRS)

A compact blackbody-pumped CO2-N2 transfer laser was constructed and the significant operating parameters were investigated. Lasing was achieved at 10.6 microns by passing preheated N2 through a 1.5-mm-diameter nozzle to a laser cavity where the N2 was mixed with CO2 and He. An intrinsic efficiency of 0.7 percent was achieved for an oven temperature of 1473 K and N2 oven pressure of 440 torr. The optimum laser cavity consisted of a back mirror with maximum reflectivity and an output mirror with 97.5-percent reflectivity. The optimum gas mixture was 1CO2/.5He/6N2. The variation of laser output was measured as a function of oven temperature, nozzle diameter, N2 oven pressure, He and CO2 partial pressures, nozzle-to-oven separation, laser cell temperature, and output laser mirror reflectivity. With these parameters optimized, outputs approaching 1.4 watts were achieved.

Deyoung, R. J.; Higdon, N. S.

1984-01-01

361

AFRL Advanced Electric Lasers Branch - Construction and Upgrade of a 50-watt Facility-Class Sodium Guidestar Pump Laser  

NASA Astrophysics Data System (ADS)

The development of a reliable and effective laser source for pumping mesospheric sodium to generate an artificial guidestar has been well documented. From the early achievements with 589nm high-power dye lasers at the Keck and Lick observatories to the ground-breaking 50W CW FASOR (Frequency Addition Source of Optical Radiation) Guidestar at the Air Forces Starfire Optical Range (SOR), there has been intense interest in this technology from both the academic and military communities. Beginning in the fall of 2008, the Air Force Research Laboratorys Advanced Electric Lasers Branch began a project to build, test, verify and deliver an upgraded version of the SOR FASOR for use at the AF Maui Optical Station (AMOS) in the summer of 2010. This FASOR will be similar in design to the existing SOR device and produce 50W of diffraction limited, linearly polarized narrow linewidth 589nm light by combining the output of two injection-locked Nd:YAG ring lasers (operating at 1064nm and 1319nm) using resonant sum-frequency generation in a lithium triborate crystal (LBO). The upgraded features will include modularized sub-components, embedded control electronics, and a simplified cooling system. The first portion of this upgrade project is to reconstruct the current SOR FASOR components and include improved methods of regulating the gain modules of the two injection lasers. In parallel with this effort, the technical plans for the modularization and re-packaging of the FASOR will be finalized and coordinated with the staff at Maui. This presentation will summarize the result of these efforts to date and provide updates on the AMOS FASOR status. Additionally, plans for "next-generation" FASOR upgrades for both SOR and AMOS will also be discussed.

Bronder, T.; Miller, H.; Stohs, J.; Lu, C.; Baker, J.; Lucero, A.

362

High efficiency 2 micrometer laser utilizing wing-pumped Tm.sup.3+ and a laser diode array end-pumping architecture  

DOEpatents

Wing pumping a Tm.sup.3+ doped, end pumped solid state laser generates 2 .mu.m laser radiation at high average powers with high efficiency. Using laser diode arrays to end-pump the laser rod or slab in the wing of the Tm.sup.3+ absorption band near 785 nm results in 2-for-1 quantum efficiency in Tm.sup.3+ because high Tm.sup.3+ concentrations can be used. Wing pumping allows the thermal power generated in the rod or slab to be distributed over a large enough volume to make thermal management practical in the laser gain medium even at high average power operation. The approach is applicable to CW, Q-switched, and rep-pulsed free-laser operation.

Beach, Raymond J. (Livermore, CA)

1997-01-01

363

High efficiency 2 micrometer laser utilizing wing-pumped Tm{sup 3+} and a laser diode array end-pumping architecture  

DOEpatents

Wing pumping a Tm{sup 3+} doped, end pumped solid state laser generates 2 {micro}m laser radiation at high average powers with high efficiency. Using laser diode arrays to end-pump the laser rod or slab in the wing of the Tm{sup 3+} absorption band near 785 nm results in 2-for-1 quantum efficiency in Tm{sup 3+} because high Tm{sup 3+} concentrations can be used. Wing pumping allows the thermal power generated in the rod or slab to be distributed over a large enough volume to make thermal management practical in the laser gain medium even at high average power operation. The approach is applicable to CW, Q-switched, and rep-pulsed free-laser operation. 7 figs.

Beach, R.J.

1997-11-18

364

Laser diode end-pumped ND:YAG laser. Memorandum report  

SciTech Connect

100 Hz operation of a Nd:YAG laser longitudinally pumped by a 1 W peak power quasi-cw laser diode was investigated theoretically and experimentally. An optical-to-optical slope efficiency of 33%, indicating a wall-plug efficiency of 7%, was exhibited, but the threshold optical power of 330 mW was high due to poor antireflection coatings on the laser rod giving a round-trip intracavity loss of 3.1 %. The 1.064 micrometer output was observed to be diffraction-limited. The theoretical modelling of the laser's input/ output characteristics agreed well with the experimentally obtained results.

Elder, I.F.

1992-01-01

365

Powerful short-pulse lasers pumped by the light of a shock wave front  

Microsoft Academic Search

Radiation of a shock wave front proved to be very powerful light source for pumping of high power lasers. Particularly, explosively pumped iodine photodissociation lasers (EPIL) are nowadays well developed type of device of multikilojoule level, rather convenient for many applications. Usually such lasers work in free running mode and generate pulses of microsecond duration. Generating short pulses of nanosecond

Gennadi A. Kirillov; V. A. Eroshenko; Gennady G. Kochemasov; Stanislav M. Kulikov; S. N. Pevny; Stanislav A. Sukharev

2000-01-01

366

Laser induced photocatalytic degradation of hazardous dye (Safranin-O) using self synthesized nanocrystalline WO3.  

PubMed

The photocatalytic degradation of Safranin-O (known as Basic Red 2) in water using locally synthesized nanocrystalline WO(3) as a photocatalyst was investigated under UV laser irradiation. The photo-oxidation removal of the dye was monitored by UV-vis spectrophotometer. The blank experiments for either laser irradiated only Safranin-O solution or the suspension containing WO(3) and Safranin-O in the dark showed that both laser illumination and the photocatalyst were essential for the removal of Safranin-O. The effect of experimental parameters including laser energy, catalyst loading, solution pH and the initial dye concentration on photocatalytic degradation of Basic Red 2 were also investigated. Results indicate that the rate of reaction is strongly influenced by the adsorption of an azo dye into the surface of the photocatalyst materials and suggests an optimum catalyst loading and dye concentration for the degradation reaction. It was investigated that the adsorption of the dye decreases at higher alkaline pH because both catalyst and substrate are negatively charged, developing repulsive forces between them. Kinetic data obtained reveals that the rate of the reaction obeys the first-order kinetics. PMID:21177021

Hayat, K; Gondal, M A; Khaled, M M; Yamani, Z H; Ahmed, S

2011-02-28

367

Laser-diode-pumped, erbium-doped, solid-state laser with high slope efficiency  

SciTech Connect

A laser and method for producing a laser emission at a wavelength of substantially 2.8 microns is disclosed. In a preferred embodiment of the invention, the laser comprises laser diode means for emitting a pump beam at a preselected wavelength; and a crystal having a preselected host material doped with a predetermined percent concentration of erbium activator ions sufficient to produce a laser emission at substantially 2.8 microns at a slope efficiency of at least 5 percent, but preferrably 10 percent, when the crystal is pumped by the pump beam. It is well known that the human body is comprised of approximately 70% water, with various human tissues containing about 60% to 90% of water, and bone and cartilage containing about 30% to 40% of water. Since the 2.8 micron wavelength has a substantially maximum absorption in water, this 2.8 micron wavelength is the ideal wavelength to use for a large variety of medical laser applications on the human body. A 2.8 micron wavelength laser could be used for precise surgery in such exemplary applications as brain surgery, neurosurgery, eye surgery, plastic surgery, burn treatment and the removal of malignancies.

Esterowitz, L.; Allen, R.; Kintz, G.

1989-10-31

368

Laser diode pumped, erbium-doped, solid state laser with high slope efficiency  

NASA Astrophysics Data System (ADS)

A laser and method for producing a laser emission at a wavelength of substantially 2.8 microns is disclosed. In a preferred embodiment of the invention, the laser comprises laser diode means for emitting a pump beam at a preselected wavelength; and a crystal having a preselected host material doped with a predetermined percent concentration of erbium activator ions sufficient to produce a laser emission at substantially 2.8 microns at a slope efficiency of at least 5 percent, but preferrably 10 percent, when the crystal is pumped by the pump beam. It is well known that the human body is comprised of approximately 70 percent water, with various human tissues containing about 60 to 90 percent of water, and bone and cartilage containing about 30 to 40 percent of water. Since the 2.8 micron wavelength has a substantially maximum absorption in water, this 2.8 micron wavelength is the ideal wavelength to use for a large variety of medical laser applications on the human body. A 2.8 micron wavelength laser could be used for precise surgery in such exemplary applications as brain surgery, neurosurgery, eye surgery, plastic surgery, burn treatment, and the removal of malignancies.

Esterowitz, Leon; Allen, R.; Kintz, G.

1989-10-01

369

Application of highly sensitive fluorescent dyes (CyDye DIGE Fluor saturation dyes) to laser microdissection and two-dimensional difference gel electrophoresis (2D-DIGE) for cancer proteomics  

Microsoft Academic Search

Proteome data combined with histopathological information provides important, novel clues for understanding cancer biology and reveals candidates for tumor markers and therapeutic targets. We have established an application of a highly sensitive fluorescent dye (CyDye DIGE Fluor saturation dye), developed for two-dimensional difference gel electrophoresis (2D-DIGE), to the labeling of proteins extracted from laser microdissected tissues. The use of the

Setsuo Hirohashi; Tadashi Kondo

2007-01-01

370

Nd:YAG end pumped by semiconductor laser arrays for free space optical communications  

NASA Technical Reports Server (NTRS)

Preliminary experimental results are reported for a diode-pumped Nd:YAG laser employing a tightly focused end-pump geometry. The resonator configuration is planoconcave, with the pumped end of the Nd:YAG rod being coated for high reflection at 1.06 microns. This geometry rectifies nearly all the inefficiencies plaguing side-pumped schemes. This laser is further considered as a candidate for optical communication over the deep space channel.

Sipes, D. L., Jr.

1985-01-01

371

Diode pumping of a solid state laser using evanescent field fiber optic coupling: a proposed technique.  

PubMed

The use of optical fibers to evanescently couple pump energy from laser diodes to a solid state laser rod is proposed. This technique involves placing a series of optical fibers side-by-side around the barrel portion of a laser rod, parallel to the laser resonator mode. A large index difference between the core region of the optical fibers and the solid state material facilitates evanescent coupling of pump light into the laser rod. Efficient operation will be possible due to a high overlap between the laser resonating mode and the pumped volume. PMID:20700158

Howerton, P H; Cordray, D M

1991-05-20

372

Experimental studies on the determination of the dipole moments of some different laser dyes  

NASA Astrophysics Data System (ADS)

In this paper we used the Stokes shift phenomena to determine the difference in the dipole moments of the excited state ?e and ground state ?g to be ( ?e- ?g), and the polarizability ?. In this paper, we studied six different laser dyes belonging to four different classes of laser dyes which are diolefin 2,5-Distyryl pyrazine (DSB); 1,4-Bis (-pyridyl-2-vinyl) benzene (P2VB) and p-Bis-( o-methylstyryl)-benzene (Bis-MSB) with ( ?e- ?g) equal to 6.40, 6.70 and 2.98 Debye, respectively; anthracene class includes 10(4-acetoxyphenyl)-2-methyl-9-acetoxy anthracene (APMAA) with ( ?e- ?g) value of 7.25 Debye; Rhodamine B (RB) with ( ?e- ?g) value of 5.33 Debye; and Coumarin 120 (C120) with the value 3.97 Debye for ( ?e- ?g). In addition the value of both polarizability ? and the radius r of each investigated laser dye molecule are determined. Therefore, the ratio ?/ r3 for each dye is calculated to be 0.93, 0.79, 0.39, 0.37, 0.67 and 0.76 for DSP, P2VB, Bis-MSB, APMAA, RB and C120, respectively. The values of r are 4.83, 4.83, 4.90, 5.34, 5.75 and 4.11 Å for the above consequence laser dyes. These dyes are studied in a large number of different solvents. The values obtained of ( ?e- ?g) for these selected dyes are positive, which means that the excited state is more polar than the ground state.

Ghazy, R.; Azim, S. A.; Shaheen, M.; El-Mekawey, F.

2004-01-01

373

Cr-doped solid state lasers pumped by visible laser diodes  

NASA Astrophysics Data System (ADS)

Operation of Cr 3+-doped solid state lasers pumped by visible laser diodes is discussed, with performance of three of the highest efficiency devices reported in detail. Cr:LiCaAlF 6 (Cr:LiCAF), Cr:LiSrAlF 6 (Cr:LiSAF) and Cr,Nd: Gd 3Sc 2Ga 3O 12 (Cr,Nd: GSGG) have all demonstrated low threshold and high slope efficiency when pumped with diodide power as high as 1 W. Laser emission levels have approached 200 mW while slope efficiencies as high as 50% were measured. Optical characterization 3ata for each laser resonator are presented and prospects for near-term power scaling are discussed.

Scheps, Richard

1992-01-01

374

Pump-free crossed-field free-electron laser  

NASA Astrophysics Data System (ADS)

Starting from basic concepts, we propose a new kind of free-electron laser (FEL): the pump-free crossed-field FEL in which the condition Eo+Vo×Bo=0 is not satisfied, and the electron orbit without radition fields and undulator or wiggler fields is not straight line (in planar configuration) or cycloid (in magnetron-like configuration). This paper presents a fluid dynamical analysis of the pump-free crossed-field FEL, in which the space charge effect is not taken into consideration. FEL instability is found near resonance? _{ ± 1} - kdot z_a = 0. While no FEL instability is found near resonance? _q - kdot z_a ± sqrt {1 - ? mathop zlimits^2 a^? o} = 0

Zhengbiao, Ouyang; Shenggang, Liu

1987-11-01

375

Tunable, diode side-pumped Er:YAG laser  

DOEpatents

A discrete-element Er:YAG laser, side pumped by a 220 Watt peak-power InGaAs diode array, generates >500 mWatts at 2.94 {micro}m, and is tunable over a 6 nm range near about 2.936 {micro}m. The oscillator is a plano-concave resonator consisting of a concave high reflector, a flat output coupler, a Er:YAG crystal and a YAG intracavity etalon, which serves as the tuning element. The cavity length is variable from 3 cm to 4 cm. The oscillator uses total internal reflection in the Er:YAG crystal to allow efficient coupling of the diode emission into the resonating modes of the oscillator. With the tuning element removed, the oscillator produces up to 1.3 Watts of average power at 2.94 {micro}m. The duty factor of the laser is 6.5% and the repetition rate is variable up to 1 kHz. This laser is useful for tuning to an atmospheric transmission window at 2.935 {micro}m (air wavelength). The laser is also useful as a spectroscopic tool because it can access several infrared water vapor transitions, as well as transitions in organic compounds. Other uses include medical applications (e.g., for tissue ablation and uses with fiber optic laser scalpels) and as part of industrial effluent monitoring systems. 4 figs.

Hamilton, C.E.; Furu, L.H.

1997-04-22

376

Tunable, diode side-pumped Er: YAG laser  

DOEpatents

A discrete-element Er:YAG laser, side pumped by a 220 Watt peak-power InGaAs diode array, generates >500 mWatts at 2.94 .mu.m, and is tunable over a 6 nm range near about 2.936 .mu.m. The oscillator is a plano-concave resonator consisting of a concave high reflector, a flat output coupler, a Er:YAG crystal and a YAG intracavity etalon, which serves as the tuning element. The cavity length is variable from 3 cm to 4 cm. The oscillator uses total internal reflection in the Er:YAG crystal to allow efficient coupling of the diode emission into the resonating modes of the oscillator. With the tuning element removed, the oscillator produces up to 1.3 Watts of average power at 2.94 .mu.m. The duty factor of the laser is 6.5% and the repetition rate is variable up to 1 kHz. This laser is useful for tuning to an atmospheric transmission window at 2.935 .mu.m (air wavelength). The laser is also useful as a spectroscopic tool because it can access several infrared water vapor transitions, as well as transitions in organic compounds. Other uses include medical applications (e.g., for tissue ablation and uses with fiber optic laser scalpels) and as part of industrial effluent monitoring systems.

Hamilton, Charles E. (Bellevue, WA); Furu, Laurence H. (Modesto, CA)

1997-01-01

377

Diode-pumped Ho:Tm:YLF laser pumping and AgGaSe2 parametric oscillator  

NASA Technical Reports Server (NTRS)

Tuning of both the pump laser, a Ho:Tm:YLF laser operating on the 5 I 7 - 5 I 8 transition, and an AgGaSe2 parametric oscillator has been demonstrated. Tuning of the Ho:Tm:YLF laser is complicated but not frustrated by the existence of both CO2 and H2O lines in the vicinity of the laser transition. Tuning of the parametric oscillator was achieved by tuning of the pump laser. Injection seeding of the parametric oscillator on the nonresonant signal was also demonstrated. In addition, the measured efficiencies of the parametric oscillator were compared by two different methods, measuring the parametric-oscillator output energy and measuring the energy depleted from the pump. By comparison of these measurements, the intrinsic efficiency of the parametric oscillator cab be determined

Barnes, Norman P.; Murray, Keith E.; Jani, Mahendra G.; Harrell, Sarah R.

1994-01-01

378

Infrared multi-line NH3 laser and its application for pumping an InSb laser  

Microsoft Academic Search

In this paper, infrared (IR) emissions from a TE CO2 laser pumped NH3 laser are reported. 38 IR laser lines were obtained from a CO2 9R(30) line pumped NH3:N2 mixture by cooling a NH3 laser tube, and 13 lines of them were new emission lines as far as we know. Four Q-branch lines were included and the others belonged to

N. Yamabayashi; T. Yoshida; K. Miyazaki; K. Fujisawa

1979-01-01

379

Single-mode Brillouin fiber laser passively stabilized at resonance frequency with self-injection locked pump laser  

Microsoft Academic Search

We demonstrate a single-mode Brillouin fiber ring laser, which is passively stabilized at pump resonance frequency by using self-injection locking of semiconductor pump laser. Resonance condition for Stokes radiation is achieved by length fitting of Brillouin laser cavity. The laser generate single-frequency Stokes wave with linewidth less than 0.5 kHz using approximately 17-m length cavity.

V V Spirin; C A López-Mercado; P Mégret; A A Fotiadi

2012-01-01

380

2-µm Tm:Lu?O? ceramic disk laser intracavity-pumped by a semiconductor disk laser.  

PubMed

A proof-of-principle study of a 1.97-µm Tm:Lu2O3 ceramic disk laser, intracavity pumped by a 1.2-µm semiconductor disk laser, is presented. The demonstrated concept allows for improved pump absorption and takes advantage of the broad wavelength coverage provided by semiconductor disk laser technology. For thin disk lasers the small thickness of the gain element typically leads to inefficient pump light absorption. This problem is usually solved by using a complex multi-pass pump arrangement. In this study we address this challenge with a new laser concept of an intracavity pumped ceramic thin disk laser. The output power at 1.97 µm was limited to 250 mW due to heat spreader-less mounting scheme of the ceramic gain disk. PMID:24104295

Saarinen, Esa J; Vasileva, Elena; Antipov, Oleg; Penttinen, Jussi-Pekka; Tavast, Miki; Leinonen, Tomi; Okhotnikov, Oleg G

2013-10-01

381

Operation features of a longitudinal-capacitive-discharge-pumped CuBr laser  

SciTech Connect

The frequency and energy characteristics of a capacitive-discharge-pumped CuBr laser are investigated. Processes proceeding in the discharge circuit of lasers pumped in this way, in particular, pumped without an external storage capacitor are analysed. It is shown that, depending on the pumping circuit, laser levels are excited either during the charge current flow or during the discharge of electrode capacitances. The differences in the influence of the active HBr addition on the characteristics of the discharge and lasing compared to the case of a usual repetitively pulsed high-current discharge with internal electrodes are established. (lasers)

Gubarev, F A; Shiyanov, D V [V.E. Zuev Institute of Atmospheric Optics, Siberian Branch, Russian Academy of Sciences, Tomsk (Russian Federation); Evtushenko, Gennadii S [Tomsk Polytechnical University, Tomsk (Russian Federation); Sukhanov, V B

2010-01-31

382

Nd:YAG laser diode-pumped directly into the emitting level at 938 nm.  

PubMed

We present the first demonstration of Nd:YAG laser pumped directly in band at 938 nm with a high-brightness fiber-coupled laser diode. Up to 6 W of CW laser emission at 1064 nm have been obtained under an absorbed pump power of 28 W at 938 nm. A comparison between 808 nm and 938 nm pumping, realized by thermal cartography, demonstrates the very low heat generation of in-band pumping. Numerical simulations were also implemented to study and discuss the laser performance of our system. PMID:19506661

Sangla, Damien; Balembois, François; Georges, Patrick

2009-06-01

383

Microporous glass-polymer composite as a new material for solid-state dye lasers: I. Material properties  

SciTech Connect

The mechanical, optical, and thermooptical properties of a microporous glass-polymer (MPG-P) composite used as a matrix for solid-state dye lasers are studied. It is shown that the composite has a high mechanical hardness, good transparency, excellent thermooptical parameters, and high laser damage resistance, and can be also readily doped with various dyes. The analysis of physical properties of the MPG-P composite showed its advantages over other solid matrices (bulk polymers and sol-gel glasses) for applications in efficient solid-state dye lasers. (lasers, active media)

Aldag, H R; Pacheco, D P [Physical Sciences Inc., 20 New England Business Center, Andover (United States); Dolotov, S M; Ponomarenko, E P; Reznichenko, A V ['Alfa-Akonis' Research and Devices Enterprise, Dolgoprudnyi, Moscow region (Russian Federation); Koldunov, M F ['Optronika' R and D Enterprise, Dolgoprudnyi, Moscow region (Russian Federation); Kravchenko, Ya V; Manenkov, Aleksandr A [A.M. Prokhorov General Physics Institute, Russian Academy of Sciences, Moscow (Russian Federation); Roskova, G P; Tsekhomskaya, T S [I.V. Grebenshchikov Institute of Silicate Chemistry, Russian Academy of Sciences, St.Petersburg (Russian Federation)

2000-11-30

384

Pulsed hollow-cathode ion lasers: pumping and lasing parameters  

SciTech Connect

Optimal discharge conditions have been experimentally found for ion lasers excited in the hollow-cathode discharge plasma by microsecond current pulses by pumping working atoms in secondkind collisions with ions and metastable buffer-gas atoms. Measurements of the output power of krypton ion and zinc-, cadmium-, mercury-, thallium-, copper-, and gallium-vapour lasers in tubes with cathodes of different diameters showed that the pulse power reaches several tens of watts, and the average power obtained with cathodes 2 cm in diameter and a length of 40 cm or more approaches 1 W. Lasing in most media is observed simultaneously at several lines (the multi-wavelength regime). Lasing on a three-component (He - Kr - Hg) mixture is realised in the multi-wavelength regime at blue, red, and IR lines.

Zinchenko, S P; Ivanov, I G

2012-06-30

385

Pulsed hollow-cathode ion lasers: pumping and lasing parameters  

NASA Astrophysics Data System (ADS)

Optimal discharge conditions have been experimentally found for ion lasers excited in the hollow-cathode discharge plasma by microsecond current pulses by pumping working atoms in secondkind collisions with ions and metastable buffer-gas atoms. Measurements of the output power of krypton ion and zinc-, cadmium-, mercury-, thallium-, copper-, and gallium-vapour lasers in tubes with cathodes of different diameters showed that the pulse power reaches several tens of watts, and the average power obtained with cathodes 2 cm in diameter and a length of 40 cm or more approaches 1 W. Lasing in most media is observed simultaneously at several lines (the multi-wavelength regime). Lasing on a three-component (He — Kr — Hg) mixture is realised in the multi-wavelength regime at blue, red, and IR lines.

Zinchenko, S. P.; Ivanov, I. G.

2012-06-01

386

Nuclear-pumped lasers for large-scale applications  

SciTech Connect

Efficient initiation of large-volume chemical lasers may be achieved by neutron induced reactions which produce charged particles in the final state. When a burst mode nuclear reactor is used as the neutron source, both a sufficiently intense neutron flux and a sufficiently short initiation pulse may be possible. Proof-of-principle experiments are planned to demonstrate lasing in a direct nuclear-pumped large-volume system; to study the effects of various neutron absorbing materials on laser performance; to study the effects of long initiation pulse lengths; to demonstrate the performance of large-scale optics and the beam quality that may be obtained; and to assess the performance of alternative designs of burst systems that increase the neutron output and burst repetition rate. 21 refs., 8 figs., 5 tabs.

Anderson, R.E.; Leonard, E.M.; Shea, R.F.; Berggren, R.R.

1989-05-01

387

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

Microsoft Academic Search

Photothermal interaction of an 805-nm diode laser with an absorptive dye, indocyanine green (ICG), has been shown to be an efficacious therapy for metastatic breast tumors in a rat model when combined with immunoadjuvant. When ICG solution was injected into the target tissue, selective tissue destruction can be achieved. To study the selective photothermal interaction, temperature change in irradiated tissue

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

2002-01-01

388

Laser emission from diode-pumped Nd:YAG ceramic waveguide lasers realized by direct femtosecond-laser writing technique.  

PubMed

We report on realization of buried waveguides in Nd:YAG ceramic media by direct femtosecond-laser writing technique and investigate the waveguides laser emission characteristics under the pump with fiber-coupled diode lasers. Laser pulses at 1.06 ?m with energy of 2.8 mJ for the pump with pulses of 13.1-mJ energy and continuous-wave output power of 0.49 W with overall optical efficiency of 0.13 were obtained from a 100-?m diameter circular cladding waveguide realized in a 0.7-at.% Nd:YAG ceramic. A circular waveguide of 50-?m diameter yielded laser pulses at 1.3 ?m with 1.2-mJ energy. PMID:24663857

Salamu, Gabriela; Jipa, Florin; Zamfirescu, Marian; Pavel, Nicolaie

2014-03-10

389

HE-pumped iodine laser for plasma and high intensity interactions  

Microsoft Academic Search

The amplifier channel energetics of high power iodine laser pumped by the radiation of shock wave front is treated. Conditions are discussed when super-high light field can be obtained by focusing the phase-conjugation of laser radiation.

G. A. Kirillov; G. G. Kochemasov; S. M. Kulikov; S. N. Pevny; S. A. Sukharev

1996-01-01

390

Improving Lifetime of Quasi-CW Laser Diode Arrays for Pumping 2-Micron Solid State Lasers  

NASA Technical Reports Server (NTRS)

Operating high power laser diode arrays in long pulse regime of about 1 msec, which is required for pumping 2-micron thulium and holmium-based lasers, greatly limits their useful lifetime. This paper describes performance of laser diode arrays operating in long pulse mode and presents experimental data on the active region temperature and pulse-to-pulse thermal cycling that are the primary cause of their premature failure and rapid degradation. This paper will then offer a viable approach for determining the optimum design and operational parameters leading to the maximum attainable lifetime.

Amzajerdian, Farzin; Meadows, Byron L.; Baker, Nathaniel R.; Barnes, Bruce W.; Singh, Upendra N.; Kavaya, Michael J.

2007-01-01

391

Optically pumped 13CD3I: new TeraHertz laser transitions  

NASA Astrophysics Data System (ADS)

We investigated the 13CD3I isotopomer of methyl iodide as a source of TeraHertz laser radiation using the optical pumping technique. We used a pulsed waveguide CO2 laser as the pump laser and an open Fabry-Pérot cavity for new laser line generation. We discovered 18 new laser lines with wavelengths ranging from 308.4 to 1132.7 ?m, plus two lines previously assigned to 12CD3I. All of the lines were characterized in wavelength, pump frequency offset, optimum pressure of operation, and relative polarization and intensity.

De Michele, A.; Moretti, A.; Pereira, D.

2011-06-01

392

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

Microsoft Academic Search

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

Patrick McNicholl; Harold J. Metcalf

1985-01-01

393

Synthesis of the Laser Dyes, AC2F and AC3F, and Related Compounds.  

National Technical Information Service (NTIS)

The synthesis of the laser dye, AC2F, which is 2-oxo-6,9-dimethyl-4-trifluoromethyl-6,7,8,9-tetrahydro-2H-pyrano(2,3- b)(1,8)naphthyridine, in nine steps from readily available starting materials is described. AC3F, which is the homologous 6,8,9-trimethyl...

R. A. Henry, P. R. Hammond

1977-01-01

394

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

NASA Technical Reports Server (NTRS)

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.

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

1990-01-01

395

Multi-wavelength laser from dye-doped cholesteric polymer films  

E-print Network

and Multiwavelength All-Optical Clock Recovery in Single-Mode Fiber Using the Temporal Talbot Effect," J. Lightwave," Optical Fiber Communication Conf., 2001, ME2­1. 11. H. Shi, G. Alphonse, J. Connolly, and P. Delfyett, "20Multi-wavelength laser from dye-doped cholesteric polymer films Yuhua Huang1,2,* and Shin-Tson Wu2

Wu, Shin-Tson

396

Microvascular blood flow dynamics associated with photodynamic therapy, pulsed dye laser irradiation and combined regimens  

Microsoft Academic Search

Background and Objectives: Previous in vitro studies demonstrated the potential utility of benzoporphyrin derivative monoacid ring A (BPD) photodynamic therapy (PDT) for vascular destruction. Moreover, the effects of PDT were enhanced when this intervention was followed immediately by pulsed dye laser (PDL) irradiation (PDT\\/ PDL). We further evaluate vascular effects of PDT alone, PDL alone and PDT\\/PDL in an in

Tia K. Smith; Bernard Choi; J. Stuart Nelson; Kathryn Osann; Kristen M. Kelly

2006-01-01

397

Modeling of a solar-pumped iodine laser  

NASA Technical Reports Server (NTRS)

The direct conversion in space of solar radiation into laser radiation for power transmission to earth, satellites, or deep space probes shows promise as a reasonably simple technology and may have cost advantage in deployment and greater reliability compared to other methods of space power generation and transmission. The main candidates for solar pumping are the gas dynamic, photochemical, and direct photoexcited lasers. Here consideration is given to the photochemical reaction of alkyliodides which predominantly excite the I(2P1/2) state which then lases at 1.315 microns. The iodine ground state is eventually lost to reconstituting the gas or in the formation of molecular iodine. The rates at which the gas is required to be recycled through the laser system are modest. The side exposure at 100-fold solar concentration of a 100-m long tube with a 1 sq m cross section is estimated to provide 20 kW of continuous laser output. Scaling laws and optimum operating conditions of this system are discussed.

Wilson, J. W.; Lee, J. H.

1980-01-01

398

Resonantly photo-pumped nickel-like erbium X-ray laser  

DOEpatents

A resonantly photo-pumped X-ray laser (10) that enhances the gain of seve laser lines that also lase because of collisional excitations and recombination processes, is described. The laser comprises an aluminum (12) and erbium (14) foil combination (16) that is driven by two beams (18, 20) of intense line focused (22, 24) optical laser radiation. Ground state nickel-like erbium ions (34) are resonantly photo-pumped by line emission from hydrogen-like aluminum ions (32).

Nilsen, Joseph (Livermore, CA)

1990-01-01

399

Multiwatt optically pumped ammonia laser operation in the 12–13 ?m  

Microsoft Academic Search

Design and operating caracteristics of high pulse repetition rate NH3 laser producing up to 20 W of average output power are described. The NH3 laser, operating in the 12–13 ?m region was optically pumped with a high pulse repetition rate TEA CO2 laser. Dependences of the NH3 laser output on the pump energy, ammonia and buffer gas pressures and pulse

V. Yu. Baranov; S. A. Kazakov; V. D. Pis'menny; A. I. Starodubtsev; E. P. Velikhov; Yu. A. Gorokhov; V. S. Letokhov; A. P. Dyad'kin; A. Z. Grasiuk; B. I. Vasil'yev

1978-01-01

400

Physical aspects of constructing a nuclear-pumped solid-state laser  

SciTech Connect

An investigation is reported of the physical aspects of the feasibility of constructing a nuclear-pumped solid-state laser. The active media considered for such a laser include neodymium-activated uranyl-doped crystals of yttrium aluminium garnet and several types of silicate and phosphate glasses. It is shown that the laser action in yttrium aluminium garnet and in two types of phosphate glasses may be observed when pumping is provided by the pulsed BARS-6 reactor. (lasers)

Seregin, A A; D'yachenko, P P; Lapidus, V I; Seregina, E A [State Scientific Center of the Russian Federation 'A.I. Leipunski Institute for Physics and Power Engineering', Obninsk, Kaluga Region (Russian Federation)

1999-02-28

401

Discovery of Optically Pumped Far-infrared Laser Emissions from Formic Acid and its Isotopologues  

NASA Astrophysics Data System (ADS)

An optically pumped molecular laser system with a transverse excitation scheme has been used to generate far-infrared radiation. Over 100 laser emissions with wavelengths up to 1.03 mm have been detected with this system using formic acid and several of its isotopologues. This includes ten new laser lines which are reported with their operating pressure, power, polarization with respect to the CO2 pump laser, and wavelength measured to an uncertainty of ± 0.5 ?m.

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

2014-05-01

402

The pumping mechanism for the neon-nitrogen nuclear excited laser  

NASA Technical Reports Server (NTRS)

In order to determine the physical processes for pumping this laser, a detailed study of the afterglow system has been performed. The pumping mechanism has been found to be collisional-radiative electron-ion recombination. Microwave quenching of both the laser and spontaneous afterglow light have shown conclusively that a recombination process directly produces a nitrogen atom in either the upper laser level or, more likely, in a higher lying energy level which rapidly de-excites to the upper laser level.

Cooper, G. W.; Verdeyen, J. T.; Wells, W. E.; Miley, G. H.

1976-01-01

403

Polarization/Spatial Combining of Laser-Diode Pump Beams  

NASA Technical Reports Server (NTRS)

A breadboard version of an optical beam combiner is depicted which make it possible to use the outputs of any or all of four multimode laser diodes to pump a non-planar ring oscillator (NPRO) laser. The output of each laser diode has a single-mode profile in the meridional plane containing an axis denoted the 'fast' axis and a narrower multimode profile in the orthogonal meridional plane, which contains an axis denoted the 'slow' axis and a narrower multimode profile in the orthogonal meridional plane, which contains an axis denoted the 'slow' axis. One of the purposes served by the beam-combining optics is to reduce the fast-axis numerical aperture (NA) of the laser-diode output to match the NA of the optical fiber. Along the slow axis, the unmodified laser-diode NA is already well matched to the fiber optic NA, so no further slow-axis beam shaping is needed. In this beam combiner, the laser-diode outputs are collimated by aspherical lenses, then half-wave plates and polarizing beam splitters are used to combine the four collimated beams into two beams. Spatial combination of the two beams and coupling into the optical fiber is effected by use of anamorphic prisms, mirrors, and a focusing lens. The anamorphic prisms are critical elements in the NA-matching scheme, in that they reduce the fast-axis beam width to 1/6 of its original values. Inasmuch as no slow-axis beam shaping is needed, the collimating and focusing lenses are matched for 1:1 iumaging. Because these lenses are well corrected for infinite conjugates the combiner offers diffraction-limited performance along both the fast and slow axes.

Gelsinger, Paul; Liu, Duncan

2008-01-01

404

Measurement of heat pump processes induced by laser radiation  

NASA Technical Reports Server (NTRS)

A series of experiments was performed in which a suitably tuned CO2 laser, frequency doubled by a Tl3AsSe37 crystal, was brought into resonance with a P-line or two R-lines in the fundamental vibration spectrum of CO. Cooling or heating produced by absorption in CO was measured in a gas-thermometer arrangement. P-line cooling and R-line heating could be demonstrated, measured, and compared. The experiments were continued with CO mixed with N2 added in partial pressures from 9 to 200 Torr. It was found that an efficient collisional resonance energy transfer from CO to N2 existed which increased the cooling effects by one to two orders of magnitude over those in pure CO. Temperature reductions in the order of tens of degrees Kelvin were obtained by a single pulse in the core of the irradiated volume. These measurements followed predicted values rather closely, and it is expected that increase of pulse energies and durations will enhance the heat pump effects. The experiments confirm the feasibility of quasi-isentropic engines which convert laser power into work without the need for heat rejection. Of more immediate potential interest is the possibility of remotely powered heat pumps for cryogenic use, such applications are discussed to the extent possible at the present stage.

Garbuny, M.; Henningsen, T.

1983-01-01

405

Tm,Ho:YLF laser end-pumped by a semiconductor diode laser array  

NASA Technical Reports Server (NTRS)

An Ho:YLF crystal including Tm as sensitizers for the activator Ho, is optically pumped with a semiconductor diode laser array to generate 2.1 micron radiation with a pump power to output power of efficiency as high as 68 percent. The prior-art dual sensitizer system of Er and Tm requires cooling, such as by LN2, but by using Tm alone and decreasing the concentrations of Tm and Ho, and decreasing the length of the laser rod to about 1 cm, it has been demonstrated that laser operation can be obtained from a temperature of 77 K with an efficiency as high as 68 percent up to ambient room temperature with an efficiency at that temperature as high as 9 percent.

Hemmati, Hamid (inventor)

1990-01-01

406

Efficiency of transverse pumping of a solid-state pulsed Nd:YAG laser by laser diode arrays  

Microsoft Academic Search

A Nd3+:YAG laser with a cylindrical active element transversely pumped by quasi-continuous laser-diode arrays located around its side surface is studied experimentally. The developed pumping modules with symmetric and asymmetric geometries provide the differential efficiency of 48% and 55% for multimode free-running lasing upon pumping of elements of diameter 3 and 5 mm, respectively. Under the conditions corresponding to this

Aleksandr Yu Abazadze; Georgii M. Zverev; Yurii M. Kolbatskov

2002-01-01

407

Efficiency of transverse pumping of a solid-state pulsed Nd:YAG laser by laser diode arrays  

Microsoft Academic Search

A Nd{sup 3+}:YAG laser with a cylindrical active element transversely pumped by quasi-continuous laser-diode arrays located around its side surface is studied experimentally. The developed pumping modules with symmetric and asymmetric geometries provide the differential efficiency of 48% and 55% for multimode free-running lasing upon pumping of elements of diameter 3 and 5 mm, respectively. Under the conditions corresponding to

Aleksandr Yu Abazadze; Georgii M Zverev; Yurii M Kolbatskov

2002-01-01

408

Design of TEM00 mode side-pumped Nd:YAG solar laser  

NASA Astrophysics Data System (ADS)

An alternative solar laser pumping approach is here proposed to improve substantially TEM00 mode solar laser power. The solar radiation is both collected and concentrated by four Fresnel lenses, and redirected towards a laser head by four plane folding mirrors. A secondary concentrator with four semi-cylindrical fused silica lenses is designed to compress the highly concentrated solar radiation to a Nd:YAG single-crystal rod. Optimum pumping conditions and laser resonator parameters are found through ZEMAX© and LASCAD© numerical analysis. The proposed design offers a uniform absorbed pump distribution along the laser rod which has a minimum in its central region, reducing considerably thermal lensing effects. High order mode laser power of 83 W is numerically attained with a short symmetric laser resonant cavity, leading to high collection efficiency of 20.8 W/m2 for side-pumped Nd:YAG solar laser. Large spatial overlap between the pumped volume and the fundamental mode volume is found for an asymmetric laser resonator with concave end mirrors of large radius of curvature. 47.4 W TEM00 laser output power is numerically achieved, leading to a solar laser beam brightness figure of merit of 32 W. This value is 16.8 times more than the previous record for solar-pumped laser.

Almeida, Joana; Liang, Dawei

2014-12-01

409

Diode-pumped, continuously tunable, 2.3 micron CW laser specification  

NASA Astrophysics Data System (ADS)

A room-temperature solid state laser for producing an output laser emission at any wavelength within a preselected range of wavelengths is disclosed. In a preferred embodiment, the laser comprises: a pump laser for emitting a CW pump beam at a preselected wavelength; a laser cavity defined by a first reflective element, an output coupler reflective element and a folded mirror disposed between the first reflective element and the output coupler reflective element to form a reflective path in the laser cavity; a laser crystal disposed in the laser cavity, the laser crystal being responsive to the CW pump beam at the preselected wavelength for producing a CW laser emission within a preselected range of wavelengths when the laser crystal is pumped by the CW pump beam at the preselected wavelength, the folded mirror operating to collimate the CW laser emission in the optical path between the folded mirror and the output coupler reflective element; and a tuning element disposed in the laser cavity between the folded mirror and the output coupler reflective element for tuning the collimated CW laser emission to any wavelength within the preselected range of wavelengths.

Esterowitz, Leon; Stoneman, Robert; Pinto, Joseph

1994-04-01

410

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

PubMed Central

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

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

2012-01-01

411

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

PubMed

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

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

2013-01-15

412

Parametric studies on a short pulsed KrF pumped atomic iodine laser  

Microsoft Academic Search

This paper describes parametric studies performed on a short pulsed KrF excimer pumped atomic Iodine laser. Three different approaches were used to determine the gain in the laser cell. The first technique uses a tunable diode laser to directly measure the transient gain. The second method involves measuring the energy extracted from the laser for various outcoupling mirrors and applying

B. S. Hunt

1995-01-01

413

Optimization of an explosively pumped photo-dissociation iodine laser with phase conjugation  

Microsoft Academic Search

Simulations of an explosively pumped two-stage photo-dissociation iodine laser with an SBS mirror at laser aperture 15 cm have shown a good agreement of calculation and experimental data on energy, laser power dynamics, brightness and Strehl number of output radiation. Calculations and experiments show that parasitic reflections of laser radiation from the windows of amplifiers and elements of the optical

Fedor A. Starikov; Yu. V. Dolgopolov; A. M. Dudov; N. N. Gerasimenko; Gennady G. Kochemasov; S. M. Kulikov; S. N. Pevny; A. F. Shkapa; S. P. Smyshlyaev; Stanislav A. Sukharev; L. I. Zykov

2005-01-01

414

Mode structure of delay-coupled semiconductor lasers: inuence of the pump current  

Microsoft Academic Search

We consider two identical, mutually delay-coupled semiconductor lasers and show that their compound laser modes (CLMs) | the basic continuous wave solutions | depend rather sensitively on the pump current of the lasers. Specically , we show with gures and accompanying animations how the underlying CLM structure and the associated locking region, where both lasers operate stably with the same

Hartmut Erzgraber; Bernd Krauskopf; Daan Lenstra

415

Diode end pumped laser and harmonic generator using same  

NASA Technical Reports Server (NTRS)

A second harmonic, optical generator is disclosed in which a laser diode produces an output pumping beam which is focused by means of a graded, refractive index rod lens into a rod of lasant material, such as Nd:YAG, disposed within an optical resonator to pump the lasant material and to excite the optical resonator at a fundamental wavelength. A non-linear electro-optic material such as MgO:LiNbO.sub.3 is coupled to the excited, fundamental mode of the optical resonator to produce a non-linear interaction with the fundamental wavelength producing a harmonic. In one embodiment, the gain medium and the non-linear material are disposed within an optical resonator defined by a pair of reflectors, one of which is formed on a face of the gain medium and the second of which is formed on a face of the non-linear medium. In another embodiment, the non-linear, electro-optic material is doped with the lasant ion such that the gain medium and the non-linear doubling material are co-extensive in volume. In another embodiment, a non-linear, doubling material is disposed in an optical resonator external of the laser gai medium for improved stability of the second harmonic generation process. In another embodiment, the laser gain medium andthe non-linear material are bonded together by means of an optically transparent cement to form a mechanically stable, monolithic structure. In another embodiment, the non-linear material has reflective faces formed thereon to define a ring resonator to decouple reflections from the non-linear medium back to the gain medium for improved stability.

Byer, Robert L. (Inventor); Dixon, George J. (Inventor); Kane, Thomas J. (Inventor)

1988-01-01

416

High-energy optically pumped iodine laser. I. Kinetics in an optically thick medium  

Microsoft Academic Search

The operation of a high-energy atomic iodine laser pumped by high-intensity broadband radiation is described theoretically. Nonlinear transport of pump radiation into an optically thick medium is specifically taken into account. Integrodifferential formulations are made for both planar and cylindrical geometries. The model obtains the temporal and spatial dependences of the various chemical species, gas temperature, pump radiation, and stimulated

James S. Cohen; O. P. Judd

1984-01-01

417

Characterization of Pyrromethene-BF2-Complexes as laser dyes  

NASA Astrophysics Data System (ADS)

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

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

418

Numerical modeling and optimization of the optically pumped mid-infrared molecular laser  

Microsoft Academic Search

The mathematical model of the optically pumped molecular laser has been built. The satisfactory fit of the computer simulation results with the experimental data has been established. The optimization of the CO laser with the optical pumping in (2,0) overtone was carried out by the numerical modeling methods.

S. V. Vassiliev; Marina A. Kuzmina; Tasoltan T. Basiev; Gordon D. Hager

2002-01-01

419

120-W continuous-wave diode-pumped Tm:YAG laser.  

PubMed

We present a 120-W cw diode-pumped Tm:YAG laser. The Tm:YAG rod is side pumped by three diode arrays whose radiation is coupled through compound parabolic concentrators. The maximum optical-to-optical conversion efficiency of the 2.02-mum laser output is 25.2%, with a slope efficiency of 31.2%. PMID:18066286

Lai, K S; Phua, P B; Wu, R F; Lim, Y L; Lau, E; Toh, S W; Toh, B T; Chng, A

2000-11-01

420

Pump power stability range of single-mode solid-state lasers with rod thermal lensing  

SciTech Connect

The pump power stability range of solid-state laser resonators operating in the TEM/sub 00/ mode has been thoroughly investigated. It has been shown that, for a very general resonator containing intracavity optical systems, rod thermal lensing engenders a pump power stability range which is a characteristic parameter of laser material and pump cavity, but is independent of resonator configuration. Stability ranges have been calculated and critically discussed for Nd:YAG, Nd:Glasses, Nd:Cr:GSGG, and alexandrite. The independence of the pump power stability range from the resonator configuration has been experimentally demonstrated for a CW Nd:YAG laser.

De Silvestri, S.; La Porta, P.; Magni, V.

1987-11-01

421

Temporal characterization of a picosecond extreme ultraviolet laser pumped in grazing incidence  

NASA Astrophysics Data System (ADS)

We report an experimental study of the temporal duration of a transient pumping extreme ultraviolet (XUV) laser emitted at 18.9 nm, using an ultrafast x-ray streak camera. We have investigated the shot-to-shot reproducibility of the pulse duration, as well as its behaviour as a function of several pumping parameters. Our results show that the pulse duration increases slowly with the pump pulse duration, in agreement with previous observations performed in a different geometry. The angle of the pump laser relative to the target surface also affects the XUV laser duration in a measurable way.

Meng, L.; Bourgaux, A.-C.; Bastiani-Ceccotti, S.; Guilbaud, O.; Pittman, M.; Kazamias, S.; Cassou, K.; Daboussi, S.; Ros, D.; Klisnick, A.

2012-10-01

422

Diode-Laser Pumped Far-Infrared Local Oscillator Based on Semiconductor Quantum Wells  

NASA Technical Reports Server (NTRS)

The contents include: 1) Tetrahertz Field: A Technology Gap; 2) Existing THZ Sources and Shortcomings; 3) Applications of A THZ Laser; 4) Previous Optical Pumped LW Generations; 5) Optically Pumped Sb based Intersubband Generation Whys; 6) InGaAs/InP/AlAsSb QWs; 7) Raman Enhanced Optical Gain; 8) Pump Intensity Dependence of THZ Gain; 9) Pump-Probe Interaction Induced Raman Shift; 10) THZ Laser Gain in InGaAs/InP/AlAsSb QWs; 11) Diode-Laser Pumped Difference Frequency Generation (InGaAs/InP/AlAsSb QWs); 12) 6.1 Angstrom Semiconductor Quantum Wells; 13) InAs/GaSb/AlSb Nanostructures; 14) InAs/AlSb Double QWs: DFG Scheme; 15) Sb-Based Triple QWs: Laser Scheme; and 16) Exciton State Pumped THZ Generation. This paper is presented in viewgraph form.

Kolokolov, K.; Li, J.; Ning, C. Z.; Larrabee, D. C.; Tang, J.; Khodaparast, G.; Kono, J.; Sasa, S.; Inoue, M.; Biegel, Bryan A. (Technical Monitor)

2002-01-01

423

Tunable solid-state lasers incorporating dye-doped, polymer-nanoparticle gain media  

NASA Astrophysics Data System (ADS)

Tunable laser action in the visible spectrum has been established for what is believed to be the first time by use of dye-doped, polymer-silica nanoparticle gain media. The silica nanoparticles, ranging from 9 to 12 nm in diameter, appear to be uniformly dispersed in the poly(methyl methacrylate) matrix because the optical homogeneity of the gain medium is maintained. With Rhodamine 6G dye and 30% weight-by-weight silica nanoparticles, laser action was established in the 567-603-nm range. At the peak wavelength (? ~ 580 nm), laser conversion efficiency is ~63% at a beam divergence of 1.9 mrad (~1.3 times the diffraction limit). The new solid-state gain medium also exhibits a reduction in |?n/?T|.

Duarte, F. J.; James, R. O.

2003-11-01

424

Efficient Ho:YAP laser dual-end-pumped by Tm fiber laser  

NASA Astrophysics Data System (ADS)

We report the continuous wave and acousto-optically Q-switched operation of an in-band dual-end-pumped Ho:YAP laser at room temperature. A continuous wave output power of 11.0W at 2118 nm was obtained at an absorbed pump power of 19.8 W, corresponding to a slope efficiency of 62.1%. For the Q-switched mode, a maximum pulse energy of about 1.07 mJ and a minimum pulse width of 29 ns at a repetition rate of 10 kHz were achieved, resulting in a peak power of 36.9 kW.

Wang, Zhongwei; Ma, Xiuzhen; Li, Wenhui

2014-03-01

425

Single transverse mode operation at 1345 nm wavelength of a diode-laser pumped neodymium:ZBLAN multimode fiber laser  

Microsoft Academic Search

A diode-laser pumped multitransverse-mode neodymium-doped fluoride fiber laser is shown to oscillate in the lowest-order transverse mode when the cavity conditions are optimized. The combination of good pump coupling efficiency, laser operating efficiency, and good overlap of the HE11 mode to that of a single-mode fiber, allows up to 12 mW of continuous wave (CW) power to be coupled into

C. A. Millar; S. C. Fleming; M. C. Brierley; M. H. Hunt

1990-01-01

426

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

DOEpatents

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.

Hackel, Richard P. (Livermore, CA)

1988-01-01

427

Direct solar-pumped iodine laser amplifier. Final report, 1 March 1984-28 February 1990  

SciTech Connect

The optimum conditions of a solar pumped iodine laser are found in this research for the case of a continuous wave operation and a pulsed operation. The optimum product of the pressure(p) inside the laser tube and the tube diameter(d) was pd=40 approx. 50 torr-cm on the contrary to the case of a high intensity flashlamp pumped iodine laser where the optimum value of the product is known to be pd=150 torr-cm. The pressure-diameter product is less than 1/3 of that of the high power iodine laser. During the research period, various laser materials were also studied for solar pumping. Among the laser materials, Nd:YAG is found to have the lowest laser threshold pumping intensity of about 200 solar constant. The Rhodamine 6G was also tested as the solar pumped laser material. The threshold pumping power was measured to be about 20,000 solar constant. The amplification experiment for a continuously pumped iodine laser amplifier was performed using Vortek solar simulator and the amplification factors were measured for single pass amplification and triple pass amplification of the 15 cm long amplifier tube. The amplification of 5 was obtained for the triple pass amplification.

Han, K.S.; Hwang, I.H.

1990-03-01

428

Efficient Operation of a 400 W Diode Side-Pumped Yb:YAG Planar Waveguide Laser  

Microsoft Academic Search

We present an efficient high-power planar waveguide laser consisting of a 2% doped Yb:YAG core with sapphire claddings. The planar waveguide is double-side pumped at 940 nm using two custom aberration-corrected diode laser stacks which are imaged directly into the waveguide core. A method to measure the pump uniformity has been developed, showing uniform pumping throughout the waveguide core. Lat-

Ian J. Thomson; Fernando J. F. Monjardin; Howard J. Baker; Denis R. Hall

2011-01-01

429

Scalloped hibachi and vacuum-pressure foil for Electra: Electron beam pumped KrF laser  

Microsoft Academic Search

We are developing a new type of “scalloped” hibachi structure to be deployed on Electra, a 700 Joule\\/pulse electron beam pumped KrF laser system, to improve the durability and efficiency of the pressure foil. In an e-beam pumped laser, an electron beam is generated in a high vacuum diode, and then passed through a pressure foil to pump the gain

R. Jaynes; T. Albert; F. Hegeler; J. D. Sethian

2007-01-01

430

Efficient, frequency-stable laser-diode-pumped Nd:YAG laser  

NASA Technical Reports Server (NTRS)

One of the main goals of the study was to demonstrate a low-power efficient Nd:YAG laser oscillator for applications in remote coherent Doppler anemometry. An electrical-to-optical slope efficiency of 6.5 percent has been achieved by using commercially available CW laser diodes of up to 100 mW to pump monolithic Nd:YAG rod lasers. The observed Nd:YAG oscillation threshold is at 2.3 mW of laser-diode output power, i.e., a small fraction of the rated output power. The highest Nd:YAG CW output power reached is 4.4 mW at an overall electrical-to-optical efficiency of 1.5 percent. The frequency jitter is less than 10 kHz in 0.3 s.

Zhou, B.; Kane, T. J.; Dixon, G. J.; Byer, R. L.

1985-01-01

431

Laser rods with undoped, flanged end-caps for end-pumped laser applications  

DOEpatents

A method and apparatus for achieving improved performance in a solid state laser is provided. A flanged, at least partially undoped end-cap is attached to at least one end of a laserable medium. Preferably flanged, undoped end-caps are attached to both ends of the laserable medium. Due to the low scatter requirements for the interface between the end-caps and the laser rod, a non-adhesive method of bonding is utilized such as optical contacting combined with a subsequent heat treatment of the optically contacted composite. The non-bonded end surfaces of the flanged end-caps are coated with laser cavity coatings appropriate for the lasing wavelength of the laser rod. A cooling jacket, sealably coupled to the flanged end-caps, surrounds the entire length of the laserable medium. Radiation from a pump source is focused by a lens duct and passed through at least one flanged end-cap into the laser rod. 14 figs.

Meissner, H.E.; Beach, R.J.; Bibeau, C.; Sutton, S.B.; Mitchell, S.; Bass, I.; Honea, E.

1999-08-10

432

158 BrainResearch,359(1985) 158-165 Unfocused Laser Illumination Kills Dye-Targeted Mouse Neurons  

E-print Network

) to effect cellular damage by SP. Dorsal root ganglia neurons in vitro were selec- tivelylabeled with procion Lucifer Yellow, they pre- dicted that many optically dense dyes might allow cellular destruction of effecting cellular damage using laser microbeams, fluorescent dye injections, or focused fluorescent beams 7

433

Quantitative Amplification of Genomic DNA from Histological Tissue Sections after Staining with Nuclear Dyes and Laser Capture Microdissection  

Microsoft Academic Search

Laser capture microdissection (LCM) allows the selec- tive sampling of tissue from histological sections. A prerequisite for this technique is the availability of histological dyes that do not interfere with down- stream analysis of the sampled genetic material. We have examined the effect of four histological nuclear dyes (methyl green, hematoxylin, toluidine blue O, azure B) on TaqMan polymerase chain

Torsten Ehrig; Sarki A. Abdulkadir; Suzanne M. Dintzis; Jeffrey Milbrandt; Mark A. Watson

2001-01-01

434

Threshold kinetics of a solar-simulator-pumped iodine laser  

SciTech Connect

A model of the chemical kinetics of the n-C3F7I solar-simulator-pumped iodine laser is utilized to study the major kinetic processes associated with the threshold behavior of this experimental system. Excited-state diffusion to the cell wall is the dominant limiting factor below 5 torr. Excited-state recombination with the alkyl radical and quenching by the parent gas control threshold at higher pressures. Treatment of the hyperfine splitting and uncertainty in the pressure broadening are important factors in fixing the threshold level. In spite of scatter in the experimental data caused by instabilities in the simulator high-pressure arc, reasonable agreement is achieved between the model and experiment. Model parameters arrived at are within the uncertainty range of values found in the literature.

Wilson, J.W.; Lee, Y.

1984-02-01

435

Threshold kinetics of a solar-simulator-pumped iodine laser  

NASA Technical Reports Server (NTRS)

A model of the chemical kinetics of the n-C3F7I solar-simulator-pumped iodine laser is utilized to study the major kinetic processes associated with the threshold behavior of this experimental system. Excited-state diffusion to the cell wall is the dominant limiting factor below 5 torr. Excited-state diffusion to the cell wall is the dominant limiting factor below 5 torr. Excited-state recombination with the alkyl radical and quenching by the parent gas control threshold at higher pressures. Treatment of the hyperfine splitting and uncertainty in the pressure broadening are important factors in fixing the threshold level. In spite of scatter in the experimental data caused by instabilities in the simulator high-pressure high-pressure arc, reasonable agreement is achieved between the model and experiment. Model parameters arrived at are within the uncertainty range of values found in the literature.

Wilson, J. W.; Lee, Y.; Weaver, W. R.; Humes, D. H.; Lee, J. H.

1984-01-01

436

Low-power photolytically pumped lasers: Final technical report  

SciTech Connect

We have carried out an extensive series of measurements of the time-resolved Xe/sub 2/* emission spectra following optical pumping by a short-pulse F/sub 2/ laser at 157.6 nm. Most measurements were performed using a gated Optical Multichannel Analyzer detector; we also made measurements using a scanning monochromator fitted with a photomultiplier and using a boxcar integrator for time resolution. The two sets of results agree well and show that both the singlet and triplet emission bands are broader than expected and have center wavelengths closer together than expected. Measurements were performed both at room temperature and at elevated (140/sup 0/C) and reduced (-27/sup 0/C) temperatures. The broad bandwidth of the individual spectral bands was unexpected and conflicted with a previous spectral measurement using optical pumping by the Xe* resonance line from a microwave discharge lamp. Therefore, we also performed a series of spectral measurements using this type of optical pumping. We achieved good agreement with some previous results in the literature, but not with the result in question. We conclude that the present results are reliable. The results presented in this report provide the first definitive measurement of the individual excimer emissions from each of the Xe/sub 2/(0/sub u//sup +/) and Xe/sub 2/(1/sub u/) states. From these measurements and the known ground state potential, we derived a 1/sub u/ potential that reproduces the emission band very well. However, the 1/sub u/ potential is in substantial disagreement with the recent 1/sub u/ potential derived by the Toronto group. 13 refs., 32 figs., 3 tabs.

Messing, I.; Lorents, D.C.; Eckstrom, D.J.

1987-08-01

437

Direct solar-pumped iodine laser amplifier. Final report, 1 March 1984-28 February 1990  

Microsoft Academic Search

The optimum conditions of a solar pumped iodine laser are found in this research for the case of a continuous wave operation and a pulsed operation. The optimum product of the pressure(p) inside the laser tube and the tube diameter(d) was pd=40 approx. 50 torr-cm on the contrary to the case of a high intensity flashlamp pumped iodine laser where

K. S. Han; I. H. Hwang

1990-01-01

438

One joule per Q-switched pulse diode-pumped laser  

NASA Technical Reports Server (NTRS)

Q-switched 1-J output has been achieved from diode-pumped zig-zag Nd:YAG slabs in an oscillator-amplifier configuration. The oscillator was single transverse and longitudinal model. This laser set records for Q-switched energy per pulse, and for average power from a diode-pumped laser. The laser was constructed in a rugged configuration suitable for routine laboratory use.

Holder, Lonnie E.; Kennedy, Chandler; Long, Larry; Dube, George

1992-01-01

439

The antiguiding parameter in mid-infrared optically pumped semiconductor lasers  

Microsoft Academic Search

We describe measurements of the antiguiding parameter, ?, for several optically pumped semiconductor lasers. Three laser structures were investigated; two of the lasers utilize W-quantum wells (QWs) in which 14 InAs\\/In0.4 GaSb\\/InAs QWs are imbedded in lattice-matched In0.25 GaAsSb layers. The emission wavelengths of the W lasers were ?3.5 and 4.5 ?m, respectively. The other laser, a double heterostructure (DH)

A. P. Ongstad; G. C. Dente; M. L. Tilton; R. Kaspi; J. R. Chavez

2010-01-01

440

Optical distortion due to gas- dynamic motion in a photolytically pumped cylindrical laser cavity  

SciTech Connect

The authors give a general solution for the growth of refractive disturbances caused by gas-dynamic motion accompanying diffuse photolytic pumping of a cylindrically symmetric laser medium. Results are derived in sufficient generality to reveal scaling with all important system parameters except bleaching of the pump transition. A simple bounding relation is derived which ensures the preservation of neardiffraction-limited laser beam quality. The results apply to any cylindrical gas laser pumped by an external diffusely illuminating light source. The amount of optical disturbance is characterized by the pump-band optical depth or extinction and the thermal energy release per pump-band absorption event. Specific details are given for the photodissociation atomic iodine laser; the usefulness of buffer gases to increase the heat capacity of the active medium is quantified.

Riley, M.E.; Rice, J.K.

1983-03-01

441

Blue diode-pumped solid-state-laser based on ytterbium doped laser crystals operating on the resonance zero-phonon transition  

DOEpatents

The invention provides an efficient, compact means of generating blue laser light at a wavelength near .about.493+/-3 nm, based on the use of a laser diode-pumped Yb-doped laser crystal emitting on its zero phonon line (ZPL) resonance transition at a wavelength near .about.986+/-6 nm, whose fundamental infrared output radiation is harmonically doubled into the blue spectral region. The invention is applied to the excitation of biofluorescent dyes (in the .about.490-496 nm spectral region) utilized in flow cytometry, immunoassay, DNA sequencing, and other biofluorescence instruments. The preferred host crystals have strong ZPL fluorecence (laser) transitions lying in the spectral range from .about.980 to .about.992 nm (so that when frequency-doubled, they produce output radiation in the spectral range from 490 to 496 nm). Alternate preferred Yb doped tungstate crystals, such as Yb:KY(WO.sub.4).sub.2, may be configured to lase on the resonant ZPL transition near 981 nm (in lieu of the normal 1025 nm transition). The laser light is then doubled in the blue at 490.5 nm.

Krupke, William F. (Pleasanton, CA); Payne, Stephen A. (Castro Valley, CA); Marshall, Christopher D. (Livermore, CA)

2001-01-01

442

Discharge pumped iodine monofluoride laser: operating parameters and collisional kinetics  

SciTech Connect

Lasing has been observed at five different wavelengths ranging from 472 to 497 nm from discharge pumped iodine monofluoride (IF). At the optimum output coupling 4 mJ was measured in a 30 ns FWHM pulse with a peak power of 140 kW. The merits and deficiencies of both HI and CF/sub 3/I as iodine donors are discussed. Measurements show the small signal gain to be greater than or equal to 1% cm/sup -1/ from approx. 478 to 497 nm, while much of the absorption is due to excited state of He. Limited line tunability is also demonstrated by using an internally mounted Littrow prism. Quenching measurements of the upper and lower laser level show the lower level to be removed more rapidly, thereby avoiding bottlenecking. In addition, the upper level spontaneous emission lifetime is measured to be 17.2 +- 4.0 ns. Finally studies of the formation kinetics of the upper laser level of IF have shown I*(/sup 4/P) atoms to be an immediate precursor, while the F*(/sup 4/P) atoms are unimportant.

Dlabal, M.L.

1981-01-01

443

Femtosecond Yb:KGd(WO4)2 laser oscillator pumped by a high power fiber-coupled diode  

E-print Network

Femtosecond Yb:KGd(WO4)2 laser oscillator pumped by a high power fiber-coupled diode laser module oscillator is reported. The laser was pumped by a 25W fiber-coupled diode laser module operating at 980 nm.major@utoronto.ca Abstract: The development and characterization of a diode-pumped ultrashort pulse Yb:KGd(WO4)2 laser

Major, Arkady

444

Investigation of Diode Pumped Alkali Laser atmospheric transmission using tunable diode laser absorption spectroscopy  

NASA Astrophysics Data System (ADS)

A field deployable ruggedized tunable diode laser absorption spectroscopy (TDLAS) device fiber coupled to a pair of 12.5" Ritchey-Chretien telescopes was used to study atmospheric propagation for open path lengths of 100 to 1,000 meters to estimate atmospheric transmission at key High Energy Laser (HEL) wavelengths. The potassium (K) version of the Diode Pumped Alkali Laser (DPAL) operates in between two of the sharp oxygen rotational features in the PP and the PQ branches. The device can be used to observe rotational temperature, concentrations, and atmospheric pressure. Molecular oxygen absorption lines near the potassium, and water vapor absorption lines near the rubidium and cesium DPALs at wavelengths near 770 nm, 795 nm, and 895 nm, respectively, were investigated using the Line-by-Line Radiative Transfer Model (LBLRTM) with the High Energy Laser End-to-End Simulation (HELEEOS). A tunable diode laser absorption spectroscopy (TDLAS) device was used to anchor simulations to actual outdoor atmospheric open-path collections. The implications of different laser gain cell configurations in DPAL systems are discussed, including spectral lineshape and atmospheric transmittance and are compared to existing high power laser systems.

Rice, Christopher A.

445

20 Watt CW TEM00 intracavity doubled optically pumped semiconductor laser at 532 nm  

NASA Astrophysics Data System (ADS)

Optically-pumped semiconductor (OPS) lasers are power-scalable, wavelength-flexible, infrared brightness converters. Adding intra-cavity frequency doubling turns them into efficient, low noise, high power visible laser sources. We report on a laser combining an InGaAs gain medium with an LBO nonlinear crystal to produce more than 20 Watt CW in single transverse mode at 532 nm. Efficient cooling of the single gain chip using advanced mounting techniques is the key to making the laser reliable at high CW powers. A rugged and compact package withstands significant environmental excursions. The laser's low noise makes it suitable for demanding Ti:Sapphire pumping applications.

Berger, Jill D.; Anthon, Douglas W.; Caprara, Andrea; Chilla, Juan L.; Govorkov, Sergei V.; Lepert, Arnaud Y.; Mefferd, Wayne; Shu, Qi-Ze; Spinelli, Luis

2012-03-01

446

Direct solar-pumped iodine laser amplifier. Semiannual progress report, 1 March-30 September 1987  

SciTech Connect

This semiannual progress report covers the period from March 1, 1987 to September 30, 1987 under NASA grant NAG1-441 entitled Direct solar-pumped iodine laser amplifier. During this period Nd:YAG and Nd:Cr:GSGG crystals have been tested for the solar-simulator pumped cw laser, and loss mechanisms of the laser output power in a flashlamp-pumped iodine laser also have been identified theoretically. It was observed that the threshold pump-beam intensities for both Nd:YAG and Nd:Cr:GSGG crystals were about 1000 solar constants, and the cw laser operation of the Nd:Cr:GSGG crystal was more difficult than that of the Nd:YAG crystal under the solar-simulator pumping. The possibility of the Nd:Cr:GSGG laser operation with a fast continuously chopped pumping was also observed. In addition, good agreement between the theoretical calculations and the experimental data on the loss mechanisms of a flashlamp-pumped iodine laser at various fill pressures and various lasants was achieved.

Han, K.S.

1987-10-01

447

Investigation of new stilbazolium dye thin films deposited by pulsed laser deposition  

NASA Astrophysics Data System (ADS)

In present work we report the analysis of thin films and targets from new stilbazolium dye E-4-(2-(4- hydroxynaphthalen-1-yl)vinyl)-1-octylquinolinium iodide (D1) deposited by Pulsed Laser Deposition (PLD) technique using high power UV TEA N2 laser. The thin films are deposited onto substrates - KBr, 316L SS alloy, optical glass and aluminum foil. The films were characterized by FTIR spectroscopy, bright field microscopy, fluorescence microscopy and atomic force microscopy (AFM) analysis. FTIR spectroscopic analysis of thin films and target material shows small differences between deposited films and native substance. The films are found to be homogeneous by AFM results and without any cracks and droplets on the surfaces. The present study demonstrates the ability of PLD technique to provide thin films from new stilbazolium dyes with good quality when they are applied as non-linear optical (NLO) organic materials on different type of substrates.

Sotirov, S.; Todorova, M.; Draganov, M.; Penchev, P.; Bakalska, R.; Serbezov, V.

2013-03-01

448

Laser femtosecond MPI mass spectrometry of dye-labeled nucleotides  

SciTech Connect

The development of effective methods for reading genetic information, i.e., for DNA sequencing, is a problem in molecular biomedicine. Laser-induced fluorescence techniques have already been successfully used for partial automation of the DNA sequence analysis. An alternate way is to develop laser spectroscopic techniques with a very high spatial resolution (on the level of a few angstrom units) that could be used for direct visualization (mapping) of biomolecules, DNA included. The laser projective photoion microscopy based on ultrafast resonant laser photodetachment of molecular photoions from chromophores of biomolecules adsorbed on the tip of an ion projector needle can potentially come to be such a method. This possibility is based on the following two key factors: the photoionization fragmentation site (photoion or photoelectron detachment site) can be localized with an accuracy much better than the photoionization laser wavelength and the ion projective microscopy technique makes it possible to observe the ejection site of a charged particle with a high magnification. The authors discuss how this forms the basis for the possibility of detecting molecules and chromophores with subwavelength resolution, i.e., for the development of femtosecond photoionization microscopy.

Chekalin, S.V.; Golovlev, V.V.; Matveets, Y.A.; Yartsev, A.P.; Letokhov, V.S. (Inst. of Spectroscopy, USSR Academy of Sciences, 142092 Troitsk, Moscow Region (SU)); Seidel, C.; Wolfrum, J.; Gruelich, K.O. (Inst. of Physical Chemistry, Heidelberg Univ., Heidelberg D-6900 (DE))

1990-12-01

449

Demonstration of an iodine laser pumped by an air-helium electric discharge  

E-print Network

Demonstration of an iodine laser pumped by an air-helium electric discharge B. S. Woodard, J. W and a continuous-wave laser on the 1315 nm transition of atomic iodine using the energy transferred to I(2 P1W in a supersonic flow cavity. Keywords: electric oxygen iodine laser, electric discharge, singlet oxygen, active

Carroll, David L.

450

Gain measurements on a short pulsed KrF pumped atomic iodine laser  

Microsoft Academic Search

This paper describes gain measurements on a short pulsed KrF excimer pumped atomic iodine laser. Three different approaches were used to determine the gain. The first technique uses a tunable diode laser to directly measure the transient gain. The second method involves measuring the energy extracted from the laser for various outcoupling mirrors and applying the threshold gain condition to

B. Scott Hunt; Jack McIver; Gordon D. Hager

1993-01-01

451

Analytical characterization of an end pumped rare-earth-doped double-clad fiber laser  

Microsoft Academic Search

Few steps of derivations on the rate equations have made it clear that the key issue of obtaining an analytical expression for the output laser power, from a double-clad Yb3+-doped fiber laser, is how to integrate the products between the radiation power and its respective loss coefficient for both the pump and laser waves. After examining the approximations adopted in

Zhichun Duan; Liping Zhang; Jianguo Chen

2007-01-01

452

Volume 42, number 2 OPTICSCOMMUNICATIONS 15 June 1982 ELECTRON BEAM PUMPED CW Se II LASER ~  

E-print Network

Volume 42, number 2 OPTICSCOMMUNICATIONS 15 June 1982 ELECTRON BEAM PUMPED CW Se II LASER ~ J as a function of the electron beam dischargeparameters is reported. Recently we obtained cw laser radiation from the observation of cw laser action in 15 transitions of singly ionized selenium using a d.c. electron beam

Rocca, Jorge J.

453

Tm:YLF Pumped Ho:YAG and Ho:LuAG Lasers  

NASA Technical Reports Server (NTRS)

Room temperature Ho:YAG and Ho:LuAG lasers pumped by a Tm:YLF laser demonstrated a 3.4 mJ threshold and 0.41 slope efficiency, incident optical to laser output energy. Results for numerous rod lengths, Ho concentrations, and output mirror reflectivities are presented.

Barnes, Norman P.; Reichle, Donald J.; Walsh, Brian M.; Axenson, Theresa J.

2004-01-01

454

Z-scan studies and optical limiting of nanosecond laser pulses in neutral red dye  

Microsoft Academic Search

The nonlinear optical absorption, refraction and optical limiting behaviour of an organic dye, neutral red, were investigated under excitation with nanosecond laser pulses at 532nm. The nonlinear optical responses of the material were studied both in solution and solid film, made in methanol and polyvinyl alcohol, respectively, using single-beam Z-scan technique. The open aperture Z-scans of the solution samples displayed