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1

Feasibility of solar-pumped dye lasers  

NASA Technical Reports Server (NTRS)

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

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

1987-01-01

2

Threshold pump power of a solar-pumped dye laser  

NASA Technical Reports Server (NTRS)

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

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

1988-01-01

3

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

4

Improvement of facial acne scars by the 585 nm flashlamp-pumped pulsed dye laser  

Microsoft Academic Search

Background: Hypertrophic or erythematous scars (or both) have remained notoriously difficult to treat because of their persistence or recurrence after traditional therapies. Recently, the 585 nm flashlamp-pumped pulsed dye laser has been shown to be effective in treating similar traumatic and surgical scars.Objective: Our purpose was to determine the effectiveness of the 585 nm flashlamp-pumped pulsed dye laser in the

Tina S. Alster; Thomas O. McMeekin

1996-01-01

5

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

NASA Technical Reports Server (NTRS)

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

Williams, M. D.

1984-01-01

6

Spectroscopic and kinetic studies of a dye laser pumped Br2 B TPi(0 /sub u/) X /sub g/ laser  

SciTech Connect

A dye laser pumped Br2 B TPi(0 /sub u/) X /sub g/ laser has been studied. Spectroscopic assignments have shown that lasing occurs from 10< or =J'< or =63 in 12< or =v'< or =17 using Rhodamine 590 dye. The output appeared limited to the 79--81 isotope of Br2. By utilizing stimulated emission as a monitor for laser excitation spectra, dramatic increases in the resolution were observed that exceeded the normal resolution of the dye laser. The Br2 laser operated at Br2 pressures of up to 60 Torr. A simple model to explain the characteristics of the Br2 laser is described.

Perram, G.P.; Davis, S.J.

1986-03-01

7

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

NASA Technical Reports Server (NTRS)

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

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

1991-01-01

8

Investigation of optical nonlinearities of an azo dye using a 532 nm diode-pumped Nd:YAG laser  

NASA Astrophysics Data System (ADS)

Solid-state dye-doped polymers are attractive alternatives to the conventional liquid dye systems. In this paper, the third order nonlinear optical property of Sudan III, an azo dye in solvents and dye doped polymer films measured using the Z-scan technique is reported. Multiple diffraction rings were observed when the dye doped in both the liquid and solid media was exposed to a diode-pumped Nd:YAG laser at 532 nm.

Gayathri, C.; Ramalingam, A.

2008-01-01

9

Biharmonic pumping in dye lasers with distributed feedback  

Microsoft Academic Search

We have shown that biharmonic pumping can effectively excite traveling population gratings in an active medium when mO o\\/2 +1\\/T1), and temperature gratings if mO 0xm)-1. As the order m increases the population-grating excitation efficiency decreases, while that of the temperature gratings may either increase or decrease. The times taken for the thermal and resonance processes which form the gratings

V. A. Batyrev; M. V. Korl'Kov

1984-01-01

10

Oxazine laser dyes  

DOEpatents

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

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

1992-01-01

11

Construction and Characterization of a Nanosecond Nd:YAG Laser Pumped Distributed Feedback Dye Laser Generating Picosecond Pulses  

NASA Astrophysics Data System (ADS)

We have constructed a Distributed Feedback Dye Laser (DFDL) using interferometric pumping. DFDL works according to the dynamic modulation of the gain medium creating short pulses. Shortening of the pulses, stability, and dynamic range of the DFDL were investigated. Pulses were measured with the help of a photodiode with a 30 picosecond response time. Traces were recorded with a Tektronics DSA73304D (33GHz) digital serial analyser. The gain medium contains an ethanol solution of Rhodamine 590 dye and DODCI saturable absorber. Increasing the concentration of DODCI saturable absorber resulted in significant pulse shortening (150 to 54 picoseconds). Single pulse generation was achieved when the power of the pump laser was adjusted 10 percent above the laser threshold. The central wavelength of the laser pulses was 587 nm. The mathematical modeling, optical layout of the DFDL, and the results of the temporal and spectral characterization of the laser are presented on the poster. The development of the DFDL will lead to an extensive investigation of short pulse dye lasers for educational purposes and for applications in nonlinear spectroscopy.

Clark, Timothy; Weckerly, Chris; Ujj, Laszlo

2013-03-01

12

Studies to enhance the beam quality from flashlamp pumped dye lasers  

SciTech Connect

A number of techniques have been considered for reducing the divergence of the beam of energy generated by a flashlamp pumped dye laser, particularly for those lasers with a high Fresnel number. The principal motivation is to enhance the brightness of such laser beams. The techniques that have been evaluated, or are under active investigation, include: (1) solvent effects; (2) unstable resonators; (3) telescopic resonators; (4) oscillator amplifier configurations; and (5) phase conjugation techniques. Results are presented that show that judicious choice of solvents can give a modest reduction in divergence and improvements of at least a factor two in beam brightness. More sophisticated techniques such as the use of a telescopic resonator can enhance the brightness by a factor in excess of 200. There is scope for further improvement in beam quality by suitable combinations of techniques or materials.

Titterton, D.H.; Winstanley, P.A.; Finlayson, A.J.; Case, A.D.; Llewelyn, E.S. [DRA Farnborough (United Kingdom)

1994-12-31

13

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

14

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

15

Generation of 10 mW tunable narrowband radiation around 210 nm using a 6.5 kHz repetition rate copper vapour laser pumped dye laser  

NASA Astrophysics Data System (ADS)

A reliable laser system, capable of generating 10 mW average power of tunable narrowband deep UV radiation around 210 nm is demonstrated. The system is based on a 6.5 kHz repetition rate copper vapour laser pumped dye laser. The dye laser emission is subsequently tripled by phasematched second harmonic generation and sum-frequency mixing in two BBO crystals. An application of the present system for high resolution excitation around 213 nm of the 1B 2( 1? +u) state of the CS 2 molecule and a resultant total fluorescence spectrum is given as an example.

Koprinkov, I. G.; Naylor, G. A.; Pique, J. P.

1994-01-01

16

Diode pumped distributed Bragg reflector lasers based on a dye-to-polymer energy transfer blend  

NASA Astrophysics Data System (ADS)

We report the demonstration of a compact, all-solid-state polymer laser system comprising of a Gallium Nitride (GaN) semiconductor diode laser as the pump source. The polymer laser was configured as a surface emitting, distributed Bragg reflector laser (DBR), based on a novel energy transfer blend of Coumarin 102 and the conjugated polymer poly(2-methoxy-5-(2’-ethylhexyloxy)-1,4-phenylene vinylene). In this configuration, diode pumping was possible both due to the improved quality of the resonators and the improved harvesting of the diode laser light.

Vasdekis, A. E.; Tsiminis, G.; Ribierre, J.-C.; O'Faolain, Liam; Krauss, T. F.; Turnbull, G. A.; Samuel, I. D. W.

2006-10-01

17

Dye system for dye laser applications  

DOEpatents

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

Hammond, Peter R. (Livermore, CA)

1991-01-01

18

Dye laser amplifier  

DOEpatents

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

Moses, E.I.

1992-12-01

19

Optofluidic dye lasers  

Microsoft Academic Search

Optofluidic dye lasers are microfabricated liquid dye lasers enabled by the microfluidics technology. The integration of dye\\u000a lasers with microfluidics not only facilitates the implementation of complete “lab-on-a-chip” systems, but also allows the\\u000a dynamical control of the laser properties which is not achievable with solid-state optical components. We review the recent\\u000a demonstrations of on-chip liquid dye lasers and some of

Zhenyu Li; Demetri Psaltis

2008-01-01

20

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

21

Ultrafast distributed feedback dye lasers  

NASA Astrophysics Data System (ADS)

A distributed feedback dye laser (DFDL) was experimentally studied to determine the utmost lower limit on ultrafast pulse generation. The ultimate aim was to determine its suitability as a cheaper high peak power laser source. The dye cell was excited by the second harmonic of a laboratory built cavity dumped passively q switched and modelocked Nd:YAG Laser to induce temperature phase grating in dye solution. Different features studied include threshold conditions, pulse shortening, by reducing cavity length, polymerization limitations, simultaneous induction of multiple superimposed gratings, line narrowing, polarization, temporal and spectral characteristics. The pump polarization affect on dynamic gratings and threshold conditions indicated the number of lasing lines (maximum nine) or intensity of a single line depends upon the state of pump polarization (SOP). Various types of tuning methods such as Bragg index, refractive index, half angle and state of pump polarization were tested for improved divergence, bandwidth, line-width and wider spectral ranges. The combined effect of coherence length and SOP of excitation laser on emission of multiple lines was studied without using external gratings. The results of this critical and contemporary work on DFDL is in agreement with most of the published results and opens a new era for their potential suitability in optical communication, sensing and photonic devices.

Khan, Nasrullah

2000-04-01

22

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

23

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

24

Diode-pumped polymer lasers  

NASA Astrophysics Data System (ADS)

In this paper we describe the design and performance of diode-pumped organic lasers based on the poly(paraphenylene-vinylene) derivative MEH-PPV. To achieve the very low oscillation thresholds required for direct diode pumping, we use a novel surface-emitting distributed Bragg reflector cavity. We describe the operating characteristics of such devices when operating below and above threshold, and show that they can combine low threshold operation with the favourable spectral and emission characteristics of DFB lasers. We also describe and characterize an energy transfer gain medium using coumarin 102 laser dye as the host, which has been optimized for efficient harvesting of the diode laser excitation.

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

2007-09-01

25

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

26

Chemical stabilization of laser dyes  

NASA Astrophysics Data System (ADS)

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

Koch, Tad H.

1987-05-01

27

Continuous-wave organic dye lasers and methods  

DOEpatents

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

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

2014-09-16

28

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

PubMed Central

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

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

2014-01-01

29

Use of flashlamp-pumped pulsed dye laser in the treatment of superficial vascular malformations and ulcerated hemangiomas.  

PubMed

A retrospective study of 502 patients treated with tunable flashlamp pulsed dye laser for superficial vascular malformations (433), ulcerated hemangiomas (65) and postinvolutional redness (4) is presented. Patients were treated in the period from June 1997 to March 2006, with follow-up ranging from six months to four years. The age of the patients ranged from three months to 80 years. Correlation between clinical response and patients' age, location of lesion and number of treatments were evaluated in groups of superficial vascular malformations, whereas healing rates of the ulceration were assessed in a series of hemangiomas. The result were judged to be excellent in 51%, good in 39%, fair in 7% and poor in 3% of patients with vascular malformations. Excellent ultimate outcome confirmed the clinical efficacy of the use of the pulsed dye laser in the treatment of dermal vascular malformations, which also appears to have good prospects in the management of hemangioma complication. PMID:21282744

Di Maio, Luigi; Baldi, Alfonso; Dimaio, Valerio; Barzi, Alberto

2011-01-01

30

Superthin resonator dye laser with THz intermode frequency separation  

NASA Astrophysics Data System (ADS)

Two-color laser irradiation is considered an effective way to pump THz excitations for numerous scientific and applied goals. We present a design for convenient laser source with THz intermode frequency separation. The setup is based on dye laser with superthin resonator pumped by a subnanosecond pulse laser. It was proven that the superthin resonator dye laser is useful, possesses high stability and high energy conversion, and generates narrow laser modes. The ability of this laser to pump CARS processes for THz vibrations is demonstrated.

Rudych, P. D.; Surovtsev, N. V.

2014-10-01

31

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

32

Laser properties and photostabilities of laser dyes doped in ORMOSILs  

NASA Astrophysics Data System (ADS)

Laser dyes such as rhodamine B, rhodamine 6G, pyrromethene 567, perylene orange and perylene red were doped into GPTMS-, MTES- and VTES-derived organically modified silicates (ORMOSILs) by sol-gel process. A longitudinal pumped solid-state dye laser was established with a Q-switched Nd:YAG laser source. The lifetimes of these dyes in various ORMOSILs were investigated by using such an experimental setup at a pump repetition rate of 2 Hz and pump intensity of 0.1 or 1.4 J/cm 2. The lifetime of 60 000 pulses, 50 GJ/mol in normalized photostability, was obtained for the pyrromethene 567 doped in MTES-derived ORMOSIL with the net sample thickness of 4 mm when its output energy declined to 50% of its initial value. The slope efficiencies of pyrromethene 567 and perylene orange in various host media were also measured.

Yang, Yu; Wang, Minquan; Qian, Guodong; Wang, Zhiyu; Fan, Xianping

2004-01-01

33

Continuous-wave solid-state dye laser  

NASA Astrophysics Data System (ADS)

We report the first realization of a cw solid-state dye laser. The laser medium consists of a laser dye (Rhodamine 6G) dissolved in a photopolymer. The UV-cured solution is sandwiched between two DVD substrates. The resonator design was derived from a conventional liquid solvent dye laser geometry. The laser radiation can be tuned from 565 to 615 nm by using a birefringent filter. A pump power of 2 W leads to a cw output power of more than 20 mW.

Bornemann, R.; Lemmer, U.; Thiel, E.

2006-06-01

34

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. 6 figs.

Hackel, R.P.

1992-11-24

35

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

36

Solar pumped laser  

NASA Technical Reports Server (NTRS)

A solar pumped laser is described in which the lasant is a gas that will photodissociate and lase when subjected to sunrays. Sunrays are collected and directed onto the gas lasant to cause it to lase. Applications to laser propulsion and laser power transmission are discussed.

Lee, J. H.; Hohl, F.; Weaver, W. R. (inventors)

1984-01-01

37

Diode pumped alkali lasers  

NASA Astrophysics Data System (ADS)

Diode pumped alkali lasers attract growing attention during the past several years because they have demonstrated potential to compete and, possibly, replace the best existing high power laser systems. In spite of the fact that an optically pumped alkali (potassium) vapor laser was first proposed by A.L. Schawlow and C.H. Townes in 1958, the intensive research and development of alkali vapor started only in 2003, when really efficient lasing in Rb and Cs vapors was demonstrated. The interest to this research was stimulated by the possibility of using efficient diode lasers for optical pumping of the alkali gain medium that promises high overall efficiency of the device. A variety of experiments on alkali lasers, including the demonstration of efficient Rb, Cs and K vapor lasers, power scaling experiments with multiple diode laser pumping sources and experiments on diode pumped alkali vapor amplifiers were performed during the past several years. In this paper we present a review of the most important achievements in high power alkali lasers research and development, discuss some problems existing in this field and future perspectives in DPAL development.

Zhdanov, B. V.; Knize, R. J.

2011-11-01

38

Dye laser for lidar ozonometry  

Microsoft Academic Search

Thus results have been published in Ref. 2 of observations of ozone in the lower layers of the atmosphere with the help of lidar, but the necessary measurement accuracy was not obtained due to insufficient energy of the laser pulses. A detailed analysis of the possibility of such measurements [3] has shown the need to use a dye laser with

P. A. Baranov; V. I. Kozintsev; V. N. Makarov; V. G. Nikiforov; A. N. Novoselov

1982-01-01

39

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

40

Theoretical studies of solar-pumped lasers  

NASA Technical Reports Server (NTRS)

Possible types of lasers were surveyed for solar power conversion. The types considered were (1) liquid dye lasers, (2) vapor dye lasers, and (3) nondissociative molecular lasers. These are discussed.

Harries, W. L.

1983-01-01

41

Zeolite-dye micro lasers  

E-print Network

We present a new class of micro lasers based on nanoporous molecular sieve host-guest systems. Organic dye guest molecules of 1-Ethyl-4-(4-(p-Dimethylaminophenyl)-1,3-butadienyl)-pyridinium Perchlorat were inserted into the 0.73-nm-wide channel pores of a zeolite AlPO$_4$-5 host. The zeolitic micro crystal compounds where hydrothermally synthesized according to a particular host-guest chemical process. The dye molecules are found not only to be aligned along the host channel axis, but to be oriented as well. Single mode laser emission at 687 nm was obtained from a whispering gallery mode oscillating in a 8-$\\mu$m-diameter monolithic micro resonator, in which the field is confined by total internal reflection at the natural hexagonal boundaries inside the zeolitic microcrystals.

Vietze, U; Laeri, F; Ihlein, G; Schüth, F; Limburg, B; Abraham, M

1998-01-01

42

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

43

SOLAR PUMPED LASER MICROTHRUSTER  

SciTech Connect

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

2010-02-05

44

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

45

Solar Pumped Laser Microthruster  

SciTech Connect

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. [Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore CA 94550 (United States)

2010-10-08

46

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

47

Triplet-extinction coefficients of some laser dyes. 1  

SciTech Connect

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

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

1989-03-01

48

Selective photothermolysis of blood vessels following flashlamp-pumped pulsed dye laser irradiation: in vivo results and mathematical modelling are in agreement.  

PubMed

Laser therapy using the pulsed dye laser is the standard treatment for port-wine stains (PWS). But the mechanism of action has not been elucidated completely, yet. The dorsal skin-fold chamber model in hamsters was used to investigate the effects of laser treatment (lambda(em)=585 nm; pulse duration: 0.45 ms; fluence: 6 J per cm2) on blood vessels. Vessels (n=3394) were marked with FITC dextran (MW 150 kDa) and diameters (2-186 microm) were measured using intravital fluorescence microscopy up to 24 h following irradiation. Histology (H&E, TUNEL, CD31) was taken 1 or 24 h after irradiation. The experimental results were compared with the predictions of a mathematical model based on the finite-element method. Following irradiation treatment the number of unperfused vessels decreases with decreasing vessel diameter in vivo. Histology indicated a restriction of tissue injury to the irradiated area after 1 h. Blood vessels contained aggregated red blood cells. After 24 h tissue damage occurred also outside the irradiated area and thrombus formation was visible. These results were in agreement with the mathematical calculations. In addition to initial physical effects after pulsed dye laser treatment delayed biological processes contribute significantly to the reduction of perfused blood vessels. Because of incomplete photocoagulation of smaller blood vessels (diameter 2-16 microm) a complete bleaching of PWS seems to be unlikely. PMID:16098046

Babilas, Philipp; Shafirstein, Gal; Bäumler, Wolfgang; Baier, Jürgen; Landthaler, Michael; Szeimies, Rolf-Markus; Abels, Christoph

2005-08-01

49

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

50

Efficiency and photostability of dye-doped solid-state lasers in different hosts  

Microsoft Academic Search

We survey the preparation procedures of pyrromethene (PM) and rhodamine dyes in silica, silica–zirconia, organically modified silicate (ormosil) and organic polymer matrices. Absorption and luminescence spectra, as well as decay time fluorescence of pyrromethene dyes are given. The solid-state laser samples were tested and their efficiencies and photostabilities at transversal pumping configuration, are given. Pyrromethene 597 had the best laser

Eli Yariv; Silke Schultheiss; Tsiala Saraidarov; Renata Reisfeld

2001-01-01

51

Solid hosts for dye laser rods: Part 1, Criteria for choosing a host material  

SciTech Connect

This paper will attempt to provide selection criteria for polymers as hosts for flashlamp-pumped dye laser rods. The properties of transparent polymer materials are compared with typical inorganic crystal and glass hosts. 2 figs., 1 tab.

Erickson, G.F.

1987-01-01

52

New laser dyes based on 3-imidazopyridylcoumarin derivatives  

NASA Astrophysics Data System (ADS)

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

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

2012-03-01

53

Microfluidic dye laser integration in a lab-on-a-chip device  

NASA Astrophysics Data System (ADS)

We report on an original design and fabrication of microfluidic dye laser integrated into a functional poly-dimethylsiloxane (PDMS) lab-on-a-chip system. Soft lithography has been used for the fabrication of the microfluidic channels allowing the liquid dye circulation. The laser cavity, formed by two cleaved optical fibers with end face metallization, is directly integrated into a microfluidic channel. The active dye molecules are optically pumped by a pulsed and frequency-doubled Nd:Yag laser at 532 nm wavelength. Finally, the output laser beam is extracted and coupled into the optical fiber. As a result, the characteristics of the laser output power as a function of pumping energy density is presented. We also show that the micro dye laser we fabricated can work steadily with an average output power up to 0.35 mW. The wavelength tunability is also demonstrated with the laser system.

Kou, Qingli; Yesilyurt, Ilker; Escalier, Guilhem; Galas, Jean Christophe; Coureau, Laurent; Chen, Yong

2004-12-01

54

Effect of pump efficiency on lasing in dye-doped chiral nematic liquid crystals  

NASA Astrophysics Data System (ADS)

The purpose of this study was to investigate the effect of varying the pump efficiency of dye-doped chiral nematic liquid crystal lasers, through the dependence on absorption efficiency. Two dyes from the rhodamine subset of the xanthene family (rhodamine B and rhodamine 6G) with similar chemical properties but different absorption and emission spectra have been compared for a fixed pumping wavelength (532nm). Each dye was dissolved in E49 (a commercial nematic mixture from Merck NB-C) and the resulting mixtures characterised in terms of their absorption and laser induced fluorescence spectra. A high twisting power chiral dopant (BDH1281, also from Merck NB-C) was used to induce 1-D photonic band gaps with the high and low energy edges corresponding to the fluorescence maximum for each dye. Laser action was induced in the resulting four mixtures and typical laser parameters such as slope efficiency and threshold energy were examined for each one. The results indicate that the mixtures doped with rhodamine 6G had an absolute absorption ~ 57% greater than those doped with rhodamine B. Rhodamine 6G-doped mixtures therefore had the highest pump efficiency and lased more than 6 times more efficiently then those doped with rhodamine B. We believe that the performance of rhodamine 6G is also influenced by its greater degree of alignment with the liquid crystal host and a possible input energy dependence of the quantum efficiency of the dyes (indicated by the fluorescence characteristics of the achiral dye-doped mixtures). Further experimentation is needed to determine exactly which parameters are responsible for the superior performance of rhodamine 6G in chiral nematic lasers.

Gillespie, Carrie; Morris, Stephen M.; Coles, Harry J.

2005-04-01

55

Generation of tunable sub-picosecond pulses in the UV with a travelling wave dye laser  

NASA Astrophysics Data System (ADS)

A transverse pumped dye laser in travelling wave arrangement has been used to generate laser pulses of 10 ?J to 26 ?J, 600 fs+/-30 fs in the spectral range from 337 nm to 345 nm. The travelling wave condition, i.e. the synchronisation of pump pulse and generated pulse, was fulfilled by tilting the pulse front of the pump pulse with respect to the direction of propagation of the pulse. To introduce the necessary tilt the pump pulse was first diffracted by a grating and then imaged onto the dye cell of the travelling wave dye laser by using a cylindrical concave mirror. Pulse-front distortions due to the optical imaging were corrected with a telescope. It is shown for the first time that the generated pulses have a tilted pulse front due to the travelling wave pumping scheme. The tilt manifests itself in angular dispersion of the generated pulses.

Schmidt-Uhlig, T.; Szatmári, S.; Marowsky, G.; Simon, P.

56

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

57

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

58

Single-mode and tunable microfluidic dye lasers  

Microsoft Academic Search

We present a technology for miniaturized, chip-based liquid dye lasers, which may be integrated with microfluidic networks and planar waveguides without addition of further process steps. The microfluidic dye lasers consist of a microfluidic channel with an embedded optical resonator. The lasers are operated with Rhodamine 6G laser dye dissolved in a suitable solvent, such as ethanol or ethylene glycol,

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

2006-01-01

59

Effects of quantum noise in a dye-laser model  

NASA Astrophysics Data System (ADS)

The steady-state properties of a dye laser model with white quantum noise and strongly colored pump noise are investigated. An effective diffusion coefficient in the steady state is presented. Our coefficient differs from that of Fox and Roy [Phys. Rev. A 35, 1838 (1987)]. We compare our results with the measurements and simulations of Lett, Short, and Mandel [Phys. Rev. Lett. 52, 341 (1984)], and the results of Fox and Roy, respectively. We find that the quantum noise plays an important role in the steady-state analysis of laser fluctuations below and near threshold.

Jia, Ya; Li, Jia-Rong

1997-03-01

60

Raman-shifted dye laser for water vapor DIAL measurements  

NASA Technical Reports Server (NTRS)

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

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

1987-01-01

61

Influence of excitation conditions on laser action in organic dye solutions  

Microsoft Academic Search

The relationship between the laser action in organic dye solutions with an output energy of ~ 102 J and the pump source characteristics is discussed. It is shown that the specified conditions are satisfied best by a cavity electric-discharge pump source operating under a near-critical damped oscillatory regime. The most effective method for attaining this regime is a reduction in

B. A. Barikhin; B. S. Makaev; L. V. Sukhanov; A. I. Pavlovskii

1976-01-01

62

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

63

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

64

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

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 greater than 30 gallons/minute at a static pressure greater than 150 pounds/square inch and a specifically designed support vessel for containing the dye cell. 6 figs.

Davin, J.

1992-12-01

65

Diffusion driven optofluidic dye lasers encapsulated into polymer chips.  

PubMed

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

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

2012-10-01

66

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

67

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

PubMed Central

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. PMID:24173352

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

2013-01-01

68

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

69

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

70

Subpicosecond pulse generation in a synchronously mode-locked cw rhodamine 6G dye laser  

Microsoft Academic Search

We report the generation of wavelength-tunable subpicosecond pulses in a synchronously mode-locked rhodamine 6G dye laser, pumped directly by a mode-locked argon-ion laser (pulsewidth approx.100 psec). The nearly transform-limited subpicosecond pulses are tunable in the 5625-to 6045-A spectral range. Peak powers of approx.1 kW have been obtained.

R. K. Jain; C. P. Ausschnitt

1978-01-01

71

Far-red polyurethane-host solid-state dye laser  

SciTech Connect

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

Nikolaev, S V; Pozhar, V V; Dzyubenko, M I [A.Ya. Usikov Institute of Radiophysics and Electronics, National Academy of Sciences of Ukraine, Khar'kov (Ukraine); Doroshenko, A O [Research Institute of Chemistry, V. N. Karazin Kharkiv National University, Kharkov (Ukraine)

2009-09-30

72

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

73

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

74

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. 9 figs.

Davin, J.

1992-12-01

75

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

76

Diode-pumped laser altimeter  

NASA Technical Reports Server (NTRS)

TEM(sub 00)-mode output energies up to 22.5 mJ with 23 percent slope efficiencies were generated at 1.064 microns in a diode-laser pumped Nd:YAG laser using a transverse-pumping geometry. 1.32-micron performance was equally impressive at 10.2 mJ output energy with 15 percent slope efficiency. The same pumping geometry was successfully carried forward to several complex Q-switched laser resonator designs with no noticeable degradation of beam quality. Output beam profiles were consistently shown to have greater than 90 percent correlation with the ideal TEM(sub 00)-order Gaussian profile. A comparison study on pulse-reflection-mode (PRM), pulse-transmission-mode (PTM), and passive Q-switching techniques was undertaken. The PRM Q-switched laser generated 8.3 mJ pulses with durations as short as 10 ns. The PTM Q-switch laser generated 5 mJ pulses with durations as short as 5 ns. The passively Q-switched laser generated 5 mJ pulses with durations as short as 2.4 ns. Frequency doubling of both 1.064 microns and 1.32 microns with conversion efficiencies of 56 percent in lithium triborate and 10 percent in rubidium titanyl arsenate, respectively, was shown. Sum-frequency generation of the 1.064 microns and 1.32 microns radiations was demonstrated in KTP to generate 1.1 mJ of 0.589 micron output with 11.5 percent conversion efficiency.

Welford, D.; Isyanova, Y.

1993-01-01

77

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

NASA Technical Reports Server (NTRS)

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

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

2004-01-01

78

Suitability of Polymeric Media In Solid State Dye Lasers  

NASA Astrophysics Data System (ADS)

Solid hosts doped with organic dyes are suitable for tunable solid state lasers because of large band width in visible region. Moreover they also overcome the problems of toxicity and limited tunability due to liquid solutions of the dyes. We report fluorescence spectra of different rhodamine dyes in different solid hosts which can be quite helpful in choosing the proper solid host for solid state dye lasers.

Sharma, Amit; Saini, G. S. S.

2011-12-01

79

Diode laser-pumped solid-state lasers  

Microsoft Academic Search

Recently, interest in diode laser-pumped solid-state lasers has increased due to their advantages over flashlamp-pumped solid-state lasers. The authors present a historical overview of semiconductor diode-pumped solid-state lasers beginning with work in the early 1960's and extending to recent work on wavelength extension of these devices by laser operation on new transitions. Modeling of these devices by rate equations to

T. Y. Fan; R. L. Byer

1988-01-01

80

Lasant Materials for Blackbody-Pumped Lasers  

NASA Technical Reports Server (NTRS)

Blackbody-pumped solar lasers are proposed to convert sunlight into laser power to provide future space power and propulsion needs. There are two classes of blackbody-pumped lasers. The direct cavity-pumped system in which the lasant molecule is vibrationally excited by the absorption of blackbody radiation and laser, all within the blackbody cavity. The other system is the transfer blackbody-pumped laser in which an absorbing molecule is first excited within the blackbody cavity, then transferred into a laser cavity when an appropriate lasant molecule is mixed. Collisional transfer of vibrational excitation from the absorbing to the lasing molecule results in laser emission. A workshop was held at NASA Langley Research Center to investigate new lasant materials for both of these blackbody systems. Emphasis was placed on the physics of molecular systems which would be appropriate for blackbody-pumped lasers.

Deyoung, R. J. (editor); Chen, K. Y. (editor)

1985-01-01

81

Generation of microsecond laser pulses in polyurethane matrices doped with dyes  

SciTech Connect

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

Nikolaev, S V; Pozhar, V V; Dzyubenko, M I [A.Ya. Usikov Institute of Radiophysics and Electronics, National Academy of Sciences of Ukraine, Khar'kov (Ukraine)

2006-08-31

82

Optofluidic microcavities: Dye-lasers and biosensors  

PubMed Central

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

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

2010-01-01

83

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

84

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

85

Optically pumped isotopic ammonia laser system  

DOEpatents

An optically pumped isotopic ammonia laser system which is capable of producing a plurality of frequencies in the middle infrared spectral region. Two optical pumping mechanisms are disclosed, i.e., pumping on R(J) and lasing on P(J) in response to enhancement of rotational cascade lasing including stimulated Raman effects, and, pumping on R(J) and lasing on P(J+2). The disclosed apparatus for optical pumping include a hole coupled cavity and a grating coupled cavity.

Buchwald, Melvin I. (Santa Fe, NM); Jones, Claude R. (Los Alamos, NM); Nelson, Leonard Y. (Seattle, WA)

1982-01-01

86

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

NASA Technical Reports Server (NTRS)

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

Minato, Atsushi; Sugimoto, Nobuo; Sasano, Yasuhiro

1992-01-01

87

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

SciTech Connect

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

Mandl, A.; Klimek, D.E. [Textron Defense Systems, Everett, MA (United States)] [Textron Defense Systems, Everett, MA (United States)

1996-03-01

88

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

89

Diode Pumped Solid State Laser Photoacoustic Spectrometer  

E-print Network

Diode Pumped Solid State Laser Photoacoustic Spectrometer Jeffrey S. Pilgrim and David S. Bomse study is based on Tm3+ :YAG [3]. Other solid state lasers are available as shown in Fig. 1, which hampered by the absence of a simple tunable infrared source with moderate power. Diode pumped solid state

90

Cladding For Transversely-Pumped Laser Rod  

NASA Technical Reports Server (NTRS)

Combination of suitable dimensioning and cladding of neodymium:yttrium aluminum garnet of similar solid-state laser provides for more efficient utilization of transversely-incident pump light from diode lasers. New design overcomes some of limitations of longitudinal- and older transverse-pumping concepts and promotes operation at higher output powers in TEM00 mode.

Byer, Robert L.; Fan, Tso Yee

1989-01-01

91

Solar-pumped solid-state lasers  

Microsoft Academic Search

Results are presented for direct solar pumping of a Nd:YAG rod laser. Stable CW output of more than 60 W was obtained with a slope efficiency exceeding 2 percent. A compound parabolic concentrator, designed to increase the solar radiation coupled into the laser rod, was used in these experiments. The results are consistent with predictions based on a single solar-pumped

M. Weksler; J. Shwartz

1988-01-01

92

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

93

Diode pumped alkali vapor fiber laser  

DOEpatents

A method and apparatus is provided for producing near-diffraction-limited laser light, or amplifying near-diffraction-limited light, in diode pumped alkali vapor photonic-band-gap fiber lasers or amplifiers. Laser light is both substantially generated and propagated in an alkali gas instead of a solid, allowing the nonlinear and damage limitations of conventional solid core fibers to be circumvented. Alkali vapor is introduced into the center hole of a photonic-band-gap fiber, which can then be pumped with light from a pump laser and operated as an oscillator with a seed beam, or can be configured as an amplifier.

Payne, Stephen A. (Castro Valley, CA); Beach, Raymond J. (Livermore, CA); Dawson, Jay W. (Livermore, CA); Krupke, William F. (Pleasanton, CA)

2007-10-23

94

Diode pumped alkali vapor fiber laser  

DOEpatents

A method and apparatus is provided for producing near-diffraction-limited laser light, or amplifying near-diffraction-limited light, in diode pumped alkali vapor photonic-band-gap fiber lasers or amplifiers. Laser light is both substantially generated and propagated in an alkali gas instead of a solid, allowing the nonlinear and damage limitations of conventional solid core fibers to be circumvented. Alkali vapor is introduced into the center hole of a photonic-band-gap fiber, which can then be pumped with light from a pump laser and operated as an oscillator with a seed beam, or can be configured as an amplifier.

Payne, Stephen A. (Castro Valley, CA); Beach, Raymond J. (Livermore, CA); Dawson, Jay W. (Livermore, CA); Krupke, William F. (Pleasanton, CA)

2006-07-26

95

RICE UNIVERSITY Pulsed Dye Laser For Excitation Of Strontium  

E-print Network

RICE UNIVERSITY Pulsed Dye Laser For Excitation Of Strontium by Priya Gupta A Thesis Submitted April, 2004 #12;2 #12;#12;iii ABSTRACT Pulsed Dye Laser For Excitation Of Strontium by Priya Gupta that is used to make ultracold strontium plasma. In order to make ultracold plasma, we cool and trap strontium

Killian, Thomas C.

96

Diode-Pumped Solid State Lasers  

E-print Network

III The use ofdiode lasers instead ofHashlamps as optical pump sources for solid state lasers offers significant advantages such as higher efficiency and longer lifetime. We have demonstrated three novel lasers based on this technology. The first is a zig-zag slab laser pumped by hybrid planar microchannel-cooled diode arrays that allow high-repetition-rate operation in a pulsed mode. The second is an end-pumped laser that uses multiple diode lasers for power scalabilitywhile maintaining high efficiency and good beam quality. The third is a Yb:YAG laser, pumped by strained-layer InGaAs diode lasers, that offers advantages over AlGaAs-pumped Nd:YAG lasers. These advances should lead to lower-cost higher-power solid state lasers. I NTEREST HAS INCREASED in the past few years in using semiconductor diode lasers to excite solid state lasers based on rare-earth ion-doped transparent solids such as neodymium-doped yttrium aluminum

T. Y Fan

97

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

98

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

99

Theoretcial studies of solar-pumped lasers  

NASA Technical Reports Server (NTRS)

A method of pumping a COhZ laser by a hot cavity was demonstrated. The cavity, heated by solar radiation, should increase the efficiency of solar pumped lasers used for energy conversion. Kinetic modeling is used to examine the behavior of such a COhZ laser. The kinetic equations are solved numerically vs. time and, in addition, steady state solutions are obtained analytically. The effect of gas heating filling the lower laser level is included. The output power and laser efficiency are obtained as functions of black body temperature and gas ratios (COhZ-He-Ar) and pressures. The values are compared with experimental results.

Harries, W. L.; Fong, Z. S.

1984-01-01

100

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

101

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

102

Two-photon optically pumped molecular gas visible laser. [Ammonia  

SciTech Connect

Recent investigations of the multiphoton ionization (MPI) spectrum of gaseous ammonia have led to the discovery of a novel two-photon pumped molecular gas electronic transition laser. Resonant, two-photon electronic excitation of NH/sub 3/ in the near uv (approx. 305 nm) leads to the first observation of fluorescence from NH/sub 3/ excited states (B and C'), and, at higher pressures, to lasing action (approx. 570 nm) between numerous C' and A state vibronic levels. A frequency-doubled Nd:YAG pumped dye laser (a few mJ) is focused into a cell containing NH/sub 3/ (or ND/sub 3/). Stimulated emission is observed in the forward and backward direction at NH/sub 3/ pressures greater than approx. 200 torr, without external mirrors to provide feedback. Conversion coefficiencies (output NH/sub 3/ pulse energy/input pulse energy) as high as 2% have been observed.

Quick, C.R. Jr.; Glownia, J.H.; Tiee, J.J.; Archuleta, F.L.

1983-01-01

103

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

104

Research on solar pumped liquid lasers  

NASA Astrophysics Data System (ADS)

A solar pumped liquid laser that can be scaled up to high power (10Mw CW) for space applications was developed. Liquid lasers have the inherent advantage over gases in that they provide much higher lasant densities and thus high power densities. Liquids also have inherent 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(3+):ZrC14 liquid was chosen for its high intrinsic efficiency as well as its relatively good stability against decomposition due to protic contamination. The development and testing of the laser liquid and the development of a large solar concentrator to pump the laser was emphasized. The procedure to manufacture the laser liquid must include diagnostic tests of the solvent purity (from protic contamination) at various stages in the production process.

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

1983-03-01

105

Prospects for solar-pumped semiconductor lasers  

SciTech Connect

Approaches are discussed for a direct solar-pumped semiconductor laser. Efficiencies of 35% should be achievable, an order of magnitude better than the efficiency achieved by other solar pumped lasers. The output wavelength of a semiconductor laser will be well matched to the optimum conversion efficiency of a solar cell of the same material. Solar pumped semiconductor lasers are thus an excellent candidate for space-based energy-transmission. Recently several designs for such lasers have been proposed. A critical parameter is the sunlight intensity required for lasing. This threshold has been calculated to be in the range of 2,500 to 10,000 times solar intensity for conventional stripe laser designs, depending on assumptions. Several approaches have been recently proposed to reduce this threshold. The calculated minimum threshold is 25--50 times solar concentration, and could possible be reduced even further with use of light-trapping.

Landis, G.A. [W.J. Schafer Associates, Cleveland, OH (United States)

1994-12-31

106

Electrical pumping of color center lasers  

Microsoft Academic Search

This paper presents an assessment of the feasibility of using electrical pumping to achieve laser action in color centers in the alkali halides. We discuss mainly the self-trapped exciton in the alkali halides, which is a prime candidate for such a pumping scheme because it is known to produce strong electroluminescence. The theory of electrical contacts to insulating crystals is

R. W. Boyd; M. S. Malcuit; K. J. Teegarden

1982-01-01

107

Electrical pumping of color center lasers  

Microsoft Academic Search

This paper presents an assessment of the feasibility of using electrical pumping to achieve laser action in color centers in the alkali halides. The discussion is mainly of the self-trapped exciton in the alkali halides, which is a prime candidate for such a pumping scheme because it is known to produce strong electroluminescence. The theory of electrical contacts to insulating

R. W. Boyd; M. S. Malcuit; K. J. Teegarden

1982-01-01

108

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

109

Research on solar pumped liquid lasers  

NASA Astrophysics Data System (ADS)

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.

1985-04-01

110

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

111

A two-photon pumped polyfluorene laser  

NASA Astrophysics Data System (ADS)

A tunable two-photon pumped solid-state laser based on polyfluorene is reported. A detailed investigation of the two-photon absorption in polyfluorene for both nanosecond and femtosecond time regimes in solution, and solid-state allows the determination of the most favorable conditions for lasing. Tunable distributed feedback lasers are made by spin coating from a polyfluorene solution on corrugated silica substrates and lasing is achieved under two-photon excitation at 640 nm with an absorbed energy density at lasing threshold of 1.3 mJ/cm2. These results highlight an alternative pumping scheme for blue organic semiconductor lasers.

Tsiminis, Georgios; Ruseckas, Arvydas; Samuel, Ifor D. W.; Turnbull, Graham A.

2009-06-01

112

Stable doped hybrid sol-gel materials for solid-state dye laser  

E-print Network

Stable doped hybrid sol-gel materials for solid-state dye laser Tran H. Nhung, Michael Canva.3380, 140.3580. 1. Introduction Much research has already been devoted to solid- state dye lasers, because stability, the pyr- romethene dyes are currently the most promising dyes used for solid-state laser

Paris-Sud XI, Université de

113

A free-electron laser pumped by the soliton laser  

NASA Astrophysics Data System (ADS)

We propose a scheme for building a free-electron laser in the soft X-ray region pumped by the soliton laser. Making use of soliton laser wave evolution shape and single-pass small signal analysis, we find that this laser has two special advantages over the previous electromagnetic wave undulator free-electron lasers. One is a very small “mass-shift effect” because of the special characteristics of soliton laser; the other is that it has an additional “frequency tuning effect” based on the conventional free-electron laser's tunability. We also obtain the small signal gain and present some discussion.

Jiang, Hua-Bei

1991-09-01

114

Broad band electro-optic tuning of a CW dye laser  

NASA Astrophysics Data System (ADS)

In many practical applications involving broadband illumination, it is desirable to have intense broadband sources of high spatial coherence. Here, a simulation of such sources with a CW dye laser continuously tunable by electro-optic means over a broad spectral band is demonstrated. The proposed system employs a conventional intracavity Pockels cell with longitudinal applied electric field and cylindrical ring electrodes; the dye laser is a commercial jet-stream laser in its standard configuration. The tuning voltages (1.3 A/V for N = 1) are sufficiently low for allowing rapid tuning (62 A/microsec at 5W pump power) over a large spectral band (310 A for N = 1, 500 A for N = 3 with Rh6G). The use of the system for absolute measurements of optical delays, surface testing, and transmission by spectral modulation of light is discussed.

Chappuis, C.; Goedgebuer, J. P.

1983-08-01

115

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

116

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

117

Solar pumped lasers and their applications  

NASA Astrophysics Data System (ADS)

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.

118

Scaling studies of solar pumped lasers  

NASA Technical Reports Server (NTRS)

A progress report of scaling studies of solar pumped lasers is presented. Conversion of blackbody radiation into laser light has been demonstrated in this study. Parametric studies of the variation of laser mixture composition and laser gas temperature were carried out for CO2 and N2O gases. Theoretical analysis and modeling of the system have been performed. Reasonable agreement between predictions in the parameter variation and the experimental results have been obtained. Almost 200 mW of laser output at 10.6 micron was achieved by placing a small sapphire laser tube inside an oven at 1500 K the tube was filled with CO2 laser gas mixture and cooled by longitudinal nitrogen gas flow.

Christiansen, W. H.; Chang, J.

1985-01-01

119

Laser photolysis of fluorone dyes in a chitosan matrix  

SciTech Connect

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

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

2012-08-31

120

Synchronously pumped mode-locked Ti:Al2O3 lasers  

NASA Technical Reports Server (NTRS)

Synchronously pumped mode-locked laser operation in a Ti:Al2O3 ring laser is demonstrated. The laser pump source was a frequency-doubled Nd:YAG laser-amplifier system producing a 60-micron-long macropulse that comprised a wavetrain of mode-locked 70-ps micropulses with a 10-ns spacing (100 MHz). The Ti:Al2O3 laser consisted of a 1-cm-long crystal with faces cut at the Brewster angle and placed in a ring laser cavity configuration with a 2 percent output coupling mirror. The cavity was adjusted for a 5-ns round trip transit time, which was close to half the temporal spacing of the pump pulse. When the crystal was pumped synchronously at 532 nm with a 30-mJ macropulse, which was approximately an order of magnitude above the laser threshold, mode-locked lasing at approximately 200 MHz was obtained. This macropulse pump energy corresponds to an average micropulse pump energy of about 5 microJ at the Ti:Al2O3 crystal face. The mode-locked operation of the Ti:Al2O3 was observed only after several microseconds into the macropulse, indicating a long build-up process over many cavity trips. During this time, relaxation oscillations were observed. When mode locking started, the relaxation oscillation frequency increased by an order of magnitude. Synchronous pumping has been limited to operation with dye lasers and used either a CW or pulsed mode-locked pump source. Recent work has demonstrated CW mode-locked operation of a Ti:Al2O3 laser. The result raises the possibility that pulsed synchronous pumping may be used to obtain significantly narrowed laser pulses in Ti:Al2O3.

1988-01-01

121

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

122

Uniformity of pump intensity distribution in diode-array side-pumped laser rod  

NASA Astrophysics Data System (ADS)

Diode-pumped solid-state lasers are high efficiency, long lifetime, compact and reliable, so they have been covering a wide range of applications. Thermal effect is a major limiting factor in scaling the average power of high-power solid-state lasers, so it is a critical issue in designing diode-pumped solid-state lasers. The uniform pump intensity distribution in laser rod can weaken the influence of thermal effects in laser, and the research of improving the pump distribution uniformity has attracted a great deal of attention. People usually establish a model of single diode-bar pumped laser rod to calculate the distribution. However, for diode-array pumped high-power lasers, the model is limited and has deviation with the actual pump distribution, which cannot reflect the real working conditions in the laser. In this paper, the theoretical model of diode-array pumped laser rod is built. Based on the actual working environment of diode-array side-pumped Tm:YAG laser rod, the expression of pump intensity distribution in the laser medium is deduced. Additionally, the influence of total pump power, pump structure, Tm:YAG rod characteristic parameters and pump beam radius on pump intensity distribution are simulated and analyzed. Moreover, the parameters are optimized in order to obtain the optimistic results which are efficient to improve the uniformity of pump distribution. The results show that when the pumping distance from diode-array to the rod's surface is 3mm, the distance between two rows of diode-bars is 1mm, the absorption coefficient is 330m-1,the pump beam width is 2.5mm,the pump intensity distribution of five-way pumped laser rod is improved, and then the thermal effects could be weakened. The presented results can provide theoretical guidance to design and optimization of high-power lasers.

Liu, Wenwen; Niu, Yanxiong; Liu, Haixia; Wang, Caili; Niu, Haisha; Man, Da

2014-11-01

123

Rigrod laser-pumped-laser resonator model: I. Theoretical considerations  

NASA Astrophysics Data System (ADS)

Dilute laser materials whose ion doping is minimized are attractive because Auger up-conversion is minimized, substantially lower heat fractions result and transverse or longitudinal gain and heat deposition gradients are reduced. In addition, amplified spontaneous emission (ASE) effects are minimized as well. Lasers using dilute laser materials, however, tend to have lowered efficiencies due to the difficulty in obtaining efficient absorption in laser crystals of reasonable length. This is primarily because of the use of simple single or double-passed pump absorption schemes. While this difficulty may be overcome using multi-passed absorption pump beams, as has been successfully demonstrated in connection with the development of thin-disc lasers, higher absorption and efficiency are obtained with added complexity and cost. In this paper, we present an alternative method in which a dilute or thin absorbing laser material is placed intra-cavity to a pump laser resonator. With the absorbing laser crystal acting as an effective outcoupler, we find that the highest absorption and resonator extraction efficiencies are obtained with the most dilute or thin materials when resonator mirrors of near unity reflectivity are used. This counter-intuitive result is explained by a corresponding long photon lifetime inside the laser resonator, which effectively multi-passes the absorbing laser crystal, leading to a very high absorption efficiency.

Brown, D. C.

2014-08-01

124

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

125

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

126

Light-emitting diode pumped polymer lasers  

NASA Astrophysics Data System (ADS)

Semiconducting polymers are very promising optoelectronic materials enabling the simple fabrication of devices such as light-emitting diodes, lasers and solar cells. However, the development of polymer lasers has been hampered by the low charge mobility of these materials preventing electrically driven lasers. We find that this problem can be overcome by taking advantage of the complementary properties of inorganic semiconductors. We show that by separating the charge transporting and lasing regions in a structure combining an indium gallium nitride light-emitting diode with a semiconducting polymer distributed feedback laser, an electrically pumped hybrid polymer laser can be made. This provides a new route to simple, convenient, compact and low-cost visible lasers with the potential for applications in security, sensing, spectroscopy, and medical diagnostics.

Turnbull, G. A.; Yang, Y.; Shaw, P.; Ruseckas, A.; Samuel, I. D. W.

2008-08-01

127

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

128

A new concept for solar pumped lasers  

NASA Technical Reports Server (NTRS)

A new approach is proposed in which an intermediate body heated by sunlight is used as the pumping source for IR systems, i.e., concentration solar radiation is absorbed and reradiated via an intermediate blackbody. This body is heated by focused sunlight to a high temperature and its heat losses are engineered to be small. The cooled laser tube (or tubes) is placed within the cavity and is pumped by it. The advantage is that the radiation spectrum is like a blackbody at the intermediate temperature and the laser medium selectively absorbs this light. Focusing requirements, heat losses, and absorption bandwidths of laser media are examined, along with energy balance and potential efficiency. The results indicate that for lasers pumped through an IR absorption spectrum, the use of an intermediate blackbody offers substantial and important advantages. The loss in radiative intensity for optical pumping by a lower-temperature body is partly compensated by the increased solid angle of exposure to the radiative environment.

Christiansen, W. H.

1978-01-01

129

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

130

Longitudinally pumped pulsed Ti:S laser  

NASA Astrophysics Data System (ADS)

Our pulsed Ti:S laser is abaxial longitudinally pumped by a frequency double YAG laser with VRM unstable resonator, the Ti:S crystal is Bi-Brewster-cutting. The single output energy of the Ti:S laser is over 130 mJ at 1 Hz and over 110 mJ at 10 Hz, the efficiency is 39.6% and 36. 7% respectively, the tunable range is 0.723 approximately 0.996 micrometers with only a pair of flat mirrors, the output energy in the two ends is 1/10 of that in the center wavelength. We discuss the effect of choice of the crystal size, the angle (alpha) (between the pump beam and the cavity axis) on efficiency. We suggest that the high absorptivity, high FOM value of the crystal bring high output and high efficiency when longitudinally pumped by a flat-top laser beam. We also show the scheme of our Ti:S laser and our broad band transmitted curve of reflective mirror.

Liu, Hongfa; Yan, Baisheng; Lei, Hairong; Zhang, Guowei; Chen, Qinghan

1996-09-01

131

Longitudinally pumped pulsed Ti:S laser  

SciTech Connect

The pulsed Ti:S laser is abaxial longitudinally pumped by a frequency doubled YAG laser with VRM unstable resonator. The single output energy of the Ti:S laser is over 130mJ at 1Hz and over 110mJ at 10Hz, the efficiency is 39.6% and 36.7% respectively, the tunable range is 0.723 {approximately} 0.996 {micro}m with only a pair of flat mirrors, the output energy in the two ends is 1/10 of that in the center wavelength. The authors discuss the effect of choice of the crystal size, the angle {alpha} (between the pump beam and the cavity axis) on efficiency. They suggest that the high absorptivity, high FOM value of the crystal bring high output and high efficiency when longitudinally pumped by a flat-top laser beam. They also show the scheme of their Ti:S laser and the broad band transmitted curve of reflective mirror.

Liu Hongfa; Yan Baisheng; Lei Hairong; Zhang Guowei [Beijing Inst. of Tech. (China). Dept. of Optical Engineering; Chen, Qinghan [Southwest Inst. of Technical Physics, Chengdu (China)

1996-12-31

132

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

133

Pulsed mononode dye laser developed for a geophysical application  

NASA Technical Reports Server (NTRS)

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

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

1986-01-01

134

High power diode lasers for solid-state laser pumps  

NASA Technical Reports Server (NTRS)

The development and commercial application of high power diode laser arrays for use as solid-state laser pumps is described. Such solid-state laser pumps are significantly more efficient and reliable than conventional flash-lamps. This paper describes the design and fabrication of diode lasers emitting in the 780 - 900 nm spectral region, and discusses their performance and reliability. Typical measured performance parameters include electrical-to-optical power conversion efficiencies of 50 percent, narrow-band spectral emission of 2 to 3 nm FWHM, pulsed output power levels of 50 watts/bar with reliability values of over 2 billion shots to date (tests to be terminated after 10 billion shots), and reliable operation to pulse lengths of 1 ms. Pulse lengths up to 5 ms have been demonstrated at derated power levels, and CW performance at various power levels has been evaluated in a 'bar-in-groove' laser package. These high-power 1-cm stacked-bar arrays are now being manufactured for OEM use. Individual diode laser bars, ready for package-mounting by OEM customers, are being sold as commodity items. Commercial and medical applications of these laser arrays include solid-state laser pumping for metal-working, cutting, industrial measurement and control, ranging, wind-shear/atmospheric turbulence detection, X-ray generation, materials surface cleaning, microsurgery, ophthalmology, dermatology, and dental procedures.

Linden, Kurt J.; Mcdonnell, Patrick N.

1994-01-01

135

Feasibility study: Monodisperse polymer particles containing laser-excitable dyes  

NASA Technical Reports Server (NTRS)

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

Vanderhoff, John W.; Chen, Jing-Hong

1993-01-01

136

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

E-print Network

treatment with a 585-nm pulsed dye laser. The patients were all female, ranging in age from 47 to 67 with the NLite 585-nm pulsed dye laser (ICN Photonics, Costa Mesa, CA). The patients were all female, rangingCollagen Remodeling After 585-nm Pulsed Dye Laser Irradiation: An Ultrasonographic Analysis BRENT R

McCarthy, John E.

137

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

138

Ultra-narrow-linewidth combined CW Ti:Sapphire/Dye laser for atom cooling and high-precision spectroscopy  

E-print Network

Ultra-narrow-linewidth combined CW Ti:Sapphire/Dye laser for atom cooling and high.5 nm Ar laser 457.9 nm 514.5 nm Ar laser 457.9 nm CW Ti:Sapphire Laser Combined CW Ti:Sapphire/Dye Laser Introduction Dye laser and Ti:Sapphire laser are characterized by ability to tune over a wide

Kobtsev, Sergei M.

139

Study of acid-base dye laser systems  

Microsoft Academic Search

Rate equations with temporal, spectral and spatial dependences are derived to obtain the characteristics of the laser emission of dye molecules that undergo acid-base processes. The model has been tested to reproduce the experimental results of the laser emission due to the monoprotonated species of 4-amino-7-phenyl-8H-pyrazino[2,3-c]-1,2,6-thiadiazine 2,2-dioxide in acetonitrile. Numerical solution of the rate equations is performed to predict general

R. Weigand; J. M. Guerra

1995-01-01

140

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

141

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

142

Experimental investigation of inhomogeneously pumped injection lasers  

SciTech Connect

An investigation was made of inhomogeneously pumped injection lasers in the form of Al/sub x/Ga/sub 1-x/As--GaAs double heterostructures. Bistable operation of such lasers was demonstrated and the switching time between the two states was less than 2 x 10/sup -10/ sec. A study was made of regular pulsations of the output radiation resulting from inhomogeneous pumping. The pulsation frequency was tunable up to 2 GHz and the duration of each pulsation (spike) was less than 2.5 x 10/sup -1/ sec. It was found that the pulsation frequency obeyed fproportional(I-I/sub th/)/sup 1/2/, where I and I/sub th/ are the current through the heterodiode and the threshold value of this current, respectively.

Borodulin, V.I.; Konyaev, V.P.; Novikova, E.R.; Tager, A.A.; Tregub, D.P.; Elenkrig, B.B.

1983-03-01

143

Convenient Microscale Synthesis of a Coumarin Laser Dye Analog  

ERIC Educational Resources Information Center

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

Aktoudianakis, Evangelos; Dicks, Andrew P.

2006-01-01

144

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

145

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

146

Electrically pumped mid-infrared random lasers.  

PubMed

Electrically pumped random lasers, operating in the mid-infrared regime at ? ? 10 ?m, are realized for the first time. Randomly distributed air holes are patterned onto a quantum cascade wafer emitting in the transverse-magnetic (TM) polarization. The advantage of employing TM polarized gain medium is that TM modes are more effectively confined in the gain region, and thus improve lasing efficiency and vertical confinement compared to TE modes. PMID:24030916

Liang, Hou Kun; Meng, Bo; Liang, Guozhen; Tao, Jin; Chong, Yidong; Wang, Qi Jie; Zhang, Ying

2013-12-17

147

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

148

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

149

Average power limits of diode-laser-pumped solid-state lasers  

Microsoft Academic Search

We investigated the average power limits of diode laser pumped slab lasers and present design calculations for several laser configurations. In the laser designs, a number of diode lasers, each one of which is coupled to an optical fiber are employed to pump a solid state laser material in a zigzag slab or a disk geometry. The systems described here

Santanu Basu; Robert L. Byer

1990-01-01

150

Advanced solar energy conversion. [solar pumped gas lasers  

NASA Technical Reports Server (NTRS)

An atomic iodine laser, a candidate for the direct solar pumped lasers, was successfully excited with a 4 kW beam from a xenon arc solar simulator, thus proving the feasibility of the concept. The experimental set up and the laser output as functions of operating conditions are presented. The preliminary results of the iodine laser amplifier pumped with the HCP array to which a Q switch for giant pulse production was coupled are included. Two invention disclosures - a laser driven magnetohydrodynamic generator for conversion of laser energy to electricity and solar pumped gas lasers - are also included.

Lee, J. H.

1981-01-01

151

Comparative Histological Studies of the Tunable Dye (at 577 nm) Laser and Argon Laser: The Specific Vascular Effects of the Dye Laser  

Microsoft Academic Search

This study compares the histological changes occurring after argon laser and dye laser (operating at 577 nm) treatment of normal human skin. The initial effect of the argon laser is a diffuse nonspecific epidermal and upper dermal necrosis with subsequent cell death and a neutrophilic response at 48 hr. These changes occur at 15 joules\\/cm2 and their extent closely correlates

Jeffrey Greenwald; Seymour Rosen; R. Rox Anderson; Terence Harrist; Francille MacFarland; Joel Noe; John A. Parrish

1981-01-01

152

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

153

Interface module for transverse energy input to dye laser modules  

DOEpatents

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

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

1994-10-11

154

Dye-enhanced diode laser photocoagulation of choroidal neovascularizations  

NASA Astrophysics Data System (ADS)

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

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

1994-06-01

155

Flow tube used to cool solar-pumped laser  

NASA Technical Reports Server (NTRS)

A flow tube has been designed and constructed to provide two major functions in the application of a laser beam for transmission of both sound and video. It maintains the YAG laser at the proper operating temperature of 300 degrees K under solar pumping conditions, and it serves as a pump cavity for the laser crystal.

1968-01-01

156

Solar-pumped laser and its second harmonic generation  

Microsoft Academic Search

Solar radiation concentrated by using a large solar collector was used to optically excite a Nd:YAG laser medium and was successfully converted into coherent laser light. The maximum laser output power attained 60 W in multi-mode. This is the highest power so far reported on a solar-pumped laser. Q-switched pulse operation of the cw solar-pumped ND:YAG laser was performed by

H. Arashi; Y. Kaneda

1993-01-01

157

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

NASA Astrophysics Data System (ADS)

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

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

2008-01-01

158

Diode-side-pumped laser heads for solid-state lasers  

SciTech Connect

Principal configurations of diode-side-pumped laser heads for solid-state lasers are considered. A comparative analysis is performed for radiation characteristics of lasers with such laser heads. (review)

Grechin, Sergei G; Nikolaev, P P [Scientific-Research Institute of Radioelectronics and Laser Technology at the N.E. Bauman Moscow State Technical University, Moscow (Russian Federation)

2009-01-31

159

Solar-pumped gas laser development  

NASA Technical Reports Server (NTRS)

The direct conversion of solar radiation into an inverted population for extraction in an optical cavity holds promise as a relatively simple system design. Broad-band photoabsorption in the visible or near-UV range is required to excite large volumes of gas and to ensure good solar absorption efficiency. The state excited must be a metastable state which is not quenched by the parent gas. The emission bandwidth must be less than approximately 10 A. The system should show chemical reversibility and an insensitivity to increasing temperature. Other properties such as good quantum efficiency and kinetic efficiency are also implied. A search of electronic-vibrational transitions in diatomic molecules satisfying these conditions is now in progress. A photodissociation-pumped atomic iodine laser is now being tested under solar pumping conditions. Photodissociation studies for thallium spin-flip metastable formation will begin in the near future.

Wilson, J. W.

1981-01-01

160

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

161

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

162

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

163

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

DOEpatents

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

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

1992-12-01

164

Recalcitrant molluscum contagiosum successfully treated with the pulsed dye laser  

PubMed Central

Background and aims: Molluscum contagiosum is caused by the molluscum contagiosum virus (MCV) and is a very common skin disorder mainly involving young children Cryotherapy, curettage or some topical therapies have been applied for MC, but all of these treatments need several sessions, can be somewhat ineffective, and very painful. The present study assessed the impact of a single session of pulsed dye laser treatment of MC lesions which had proved resistant to other approaches Subjects and methods: Fifteen children comprised the study subjects, 11 boys and 4 girls, 3–5 years of age (mean 4.2 yr) with recalcitrant MC. Lesions were counted at baseline, and a single shot from a 585 nm pulsed dye laser was applied to each lesion (3 mm, 300 ms, 8.0 J/cm2). Lesions were counted again at 1 week post-treatment and followed for up to 3 months thereafter. Results: All patients completed the study and no patient dropped out through pain or discomfort. Purpura was seen at each treated lesion immediately after irradiation, but at 1 week after treatment, lesion clearance was virtually complete which was maintained for 1 month, and no recurrence was seen at 3 months in 8 of the 15 patients who remained available for followup. Conclusions: A single treatment of MC lesions with the pulsed dye laser successfully cured even recalcitrant lesions with no recurrence on follow up, and was well tolerated by the young subjects. PMID:24155550

Omi, Tokuya; Kawana, Seiji

2013-01-01

165

Collinear dual-color laser emission from a microfluidic dye laser  

Microsoft Academic Search

Collinear dual-color laser emission on a chip is obtained from a liquid dye mixture flowing through an optical microcavity. Soft lithography has been used to fabricate the microfluidic channels and integrate the optical resonator. The laser cavity, of nanoliter volume, is made of two parallel gold mirrors coated on the end faces of optical fibers and integrated into a polydimethylsiloxane

Q. Kou; I. Yesilyurt; Y. Chen

2006-01-01

166

"Diode Pumped Solid State Lasers At 2 And 3 µm"  

NASA Astrophysics Data System (ADS)

The most attractive alternative to flashlamp pumping of solid state lasers is the diode laser. In the past two decades numerous laboratory devices have been assembled which incorporated single diode lasers, small laser diode arrays or LED's for pumping of Nd:YAG, Nd:glass and a host of other Nd lasers. The low power output, low packaging density, and extremely high cost of diode lasers prevented any serious applications for laser pumping in the past. The reason for the continued interest in this area stems from the potential dramatic increase in system efficiency and component lifetime, and reduction of thermal load of the solid-state laser material. The latter not only will reduce thereto-optic effects and therefore lead to better beam quality but also will enable an increase in pulse repetition frequency. The attractive operating parameters combined with low voltage operation and the compactness of an all solid-state laser system have a potential high payoff. The high pumping efficiency compared to flashlamps stems from the good spectral match between the laser diode emission and the rare earth activator absorption bands. A significant advantage of laser diode pumping compared to arc lamps is system lifetime and reliability. Laser diode arrays have exhibited lifetimes on the order of 10,000 hours in cw operation and 109 shots in the pulsed mode. Flashlamp life is on the order of 107 shots, and about 200 hours for cw operation. In addition, the high pump flux combined with a substantial UV content in lamp pumped systems causes material degradation in the pump cavity and in the coolant. Such problems are virtually eliminated with laser diode pump sources. The absence of high voltage pulses, high temperatures and UV radiation encountered with arc lamps leads to much more benign operating features for solid state laser systems employing laser diode pumps. Laser diode technology dates back to 1962 when laser action in GaAs diodes was first demonstrated. However, it took a decade to transform a fragile device requiring cryogenic temperatures into one capable of emitting a continuous beam at room temperature. In the last few years the rapid progress in fabricating diode lasers has increased interest in developing diode pumped solid state lasers. Device fabrication improvements such as double hetero-structures, multiple quantum well structures, monolithic phased arrays and multiple stripe lasers which were made possible by improved manufacturing technologies have produced a dramatic reduction of threshold current and increases of slope efficiency, lifetime and output power.

Esterowitz, Leon

1988-06-01

167

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

168

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

NASA Astrophysics Data System (ADS)

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.; Eltokhy, A.; Harith, M. A.

2011-09-01

169

Investigation Solvation Dynamics and Isomerization of Dye IR-140 Using pump supercontinuum-probing Technique  

E-print Network

The solvation dynamics and isomerization process of an organic dye, IR-140, in polar solvents and nonpolar solvents have been investigated using pump supercontinuum-probing (PSCP) technique. In all solvents, the dynamics exhibits solvent-dependent. Solvent induced spectral shifts of the absorption and emission spectra of IR-140 have also been studied in a variety of solvents. At the same time, the photoisomerization process has been examined. The approximate energy-band structure of IR-140 was also supposed firstly.

Wang, D; Wu, S; Yang, H; Xiang, Q G J; Xu, G; Wang, Danling; Jiang, Hongbing; Wu, Songjiang; Yang, Hong; Xiang, Qihuang Gong Junfeng; Xu, Guangzhi

2001-01-01

170

Key techniques for space-based solar pumped semiconductor lasers  

NASA Astrophysics Data System (ADS)

In space, the absence of atmospheric turbulence, absorption, dispersion and aerosol factors on laser transmission. Therefore, space-based laser has important values in satellite communication, satellite attitude controlling, space debris clearing, and long distance energy transmission, etc. On the other hand, solar energy is a kind of clean and renewable resources, the average intensity of solar irradiation on the earth is 1353W/m2, and it is even higher in space. Therefore, the space-based solar pumped lasers has attracted much research in recent years, most research focuses on solar pumped solid state lasers and solar pumped fiber lasers. The two lasing principle is based on stimulated emission of the rare earth ions such as Nd, Yb, Cr. The rare earth ions absorb light only in narrow bands. This leads to inefficient absorption of the broad-band solar spectrum, and increases the system heating load, which make the system solar to laser power conversion efficiency very low. As a solar pumped semiconductor lasers could absorb all photons with energy greater than the bandgap. Thus, solar pumped semiconductor lasers could have considerably higher efficiencies than other solar pumped lasers. Besides, solar pumped semiconductor lasers has smaller volume chip, simpler structure and better heat dissipation, it can be mounted on a small satellite platform, can compose satellite array, which can greatly improve the output power of the system, and have flexible character. This paper summarizes the research progress of space-based solar pumped semiconductor lasers, analyses of the key technologies based on several application areas, including the processing of semiconductor chip, the design of small and efficient solar condenser, and the cooling system of lasers, etc. We conclude that the solar pumped vertical cavity surface-emitting semiconductor lasers will have a wide application prospects in the space.

He, Yang; Xiong, Sheng-jun; Liu, Xiao-long; Han, Wei-hua

2014-12-01

171

Solar-pumped lasers for space power transmission  

NASA Technical Reports Server (NTRS)

Multi-Megawatt CW solar-pumped lasers appear to be technologically feasible for space power transmission in the 1990s time frame. A new concept for a solar-pumped laser is presented which utilizes an intermediate black body cavity to provide a uniform optical pumping environment for the lasant, either CO or CO2. Reradiation losses are minimized with resulting high efficiency operation. A 1 MW output laser may weigh as little as 8000 kg including solar collector, black body cavity, laser cavity and ducts, pumps, power systems and waste heat radiator. The efficiency of such a system will be on the order of 10 to 20%. Details of the new concept, laser design, comparison to competing solar-powered lasers and applications to a laser solar power satellite (SPS) concept are presented.

Taussig, R.; Bruzzone, C.; Nelson, L.; Quimby, D.; Christiansen, W.

1979-01-01

172

Vanadium-pumped titanium x-ray laser  

DOEpatents

A resonantly photo-pumped x-ray laser (10) is formed of a vanadium (12) and titanium (14) foil combination (16) that is driven by two beams (18, 20) of intense line focused (22, 24) optical laser radiation. Ground state neon-like titanium ions (34) are resonantly photo-pumped by line emission from fluorine-like vanadium ions (32).

Nilsen, Joseph (Livermore, CA)

1992-01-01

173

Vanadium-pumped titanium x-ray laser  

DOEpatents

A resonantly photo-pumped x-ray laser is formed of a vanadium and titanium foil combination that is driven by two beams of intense line focused optical laser radiation. Ground state neon-like titanium ions are resonantly photo-pumped by line emission from fluorine-like vanadium ions. 4 figs.

Nilsen, J.

1992-05-26

174

CO.sub.2 optically pumped distributed feedback diode laser  

DOEpatents

A diode laser optically pumped by a CO.sub.2 coherent source. Interference fringes generated by feeding the optical pumping beam against a second beam, periodically alter the reflectivity of the diode medium allowing frequency variation of the output signal by varying the impingent angle of the CO.sub.2 laser beams.

Rockwood, Stephen D. (Los Alamos, NM)

1980-01-01

175

Multireflection Pumping Concept for Miniaturized Diode-Pumped Solid-State Lasers  

NASA Astrophysics Data System (ADS)

An innovative pump concept for diode-pumped, solid-state lasers is introduced as an example for an Er:YSGG laser, permitting its miniaturization. Embedded in a multireflective pump cavity, the laser crystal is simultaneously side and end pumped. Specially calculated and shaped deflecting optics distribute the coaxially input pumping light homogeneously over the lateral surface of the crystal, therefore reducing the size of the laser head, including the optical resonator, to a length of 27.5 mm and an outside diameter of 12.5 mm. The differential efficiency achieved is between 8.7% and 24%. The laser emits energy of 15.7 mJ at an absolute efficiency of 9.1% and a repetition rate of 4 Hz.

Meister, Jörg; Franzen, Rene; Apel, Christian; Gutknecht, Norbert

2004-11-01

176

Diode-pumped miniature solid-state laser - Design considerations  

Microsoft Academic Search

The LED-direct pumped laser was considered theoretically as a way to miniaturize solid state lasers. The pumping efficiency of the system was calculated numerically by 3-D ray tracing. For LiNdP4O12, an efficient Nd stoichiometric material, the threshold power density and the pump power density necessary to obtain a 5-mW output power under optimum output coupling conditions were calculated to be

Kenichi Kubodera; Kenju Otsuka

1977-01-01

177

Long-Lifetime Laser Materials For Effective Diode Pumping  

NASA Technical Reports Server (NTRS)

Long quantum lifetimes reduce number of diodes required to pump. Pumping by laser diodes demonstrated with such common Nd laser materials as neodymium:yttrium aluminum garnet (Nd:YAG) and Nd:YLiF4, but such materials as Nd:LaF3, Nd:NaF.9YF3, and possibly Nd:YF3 more useful because of long lifetimes of their upper laser energy levels. Cost effectiveness primary advantage of solid-state laser materials having longer upper-laser-level lifetimes. Because cost of diodes outweighs cost of laser material by perhaps two orders of magnitude, cost reduced significantly.

Barnes, Norman P.

1991-01-01

178

Quasicontinuous wave linearly polarized rubidium vapor laser pumped by a 5-bar laser diode stack  

NASA Astrophysics Data System (ADS)

We report a quasicontinuous wave (CW) linearly polarized rubidium vapor laser. The pumping source consists of five laser diode bars and its linewidth is reduced from the raw 1.8 to 0.2 nm by a bulk volume Bragg grating. Instead of adopting the "quasi-waveguide structure" gain cell, the pumping light of the rubidium vapor laser propagates freely in the vapor cell. The pumping light with polarization perpendicular to one of the rubidium laser is coupled into the resonator cavity by the polarized beam splitter. This laser configuration is suitable for a convection-cooling diode-pumped alkali vapor laser.

Li, Zhiyong; Tan, Rongqing; Huang, Wei; Zhang, Dandan

2014-11-01

179

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

180

METHODOLOGICAL NOTES: A simple dye laser for demonstrations  

NASA Astrophysics Data System (ADS)

A simple scheme is described for demonstrating laser generation of (? = 570 nm) in an ethanol solution of rhodamin 6G excited by a small N2 laser LGI-21 (P = 3kW, ? = 337 nm). The solution is placed into a cell of 4-5 mm thickness with a silver or aluminum mirror and a quartz window at the ends. Excitation is produced by a beam focused by a spherical lens through the quartz window. Radiation from the dye laser leaves the cell at a small angle in the direction opposite to the exciting beam through the same lens and this produces collimated radiation which is then aimed in the desired direction by deflecting mirrors.

Ageev, Leonid A.

1981-07-01

181

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

182

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, Peter R. (Livermore, CA)

1986-01-01

183

Optically end-pumped plastic waveguide laser with in-line Fabry-Pérot resonator.  

PubMed

A plastic waveguide laser doped with organic dye molecule was fabricated with self-written active (SWA) waveguide technique. The device has a Fabry-Perot resonator consisting of a pair of highly reflective dielectric mirrors, which has brought two advantages for efficient optical pumping; (i) the efficient optical feedback in the cavity can be induced, and (ii) the reflection band of the dielectric mirrors can be tuned to overlap only with the emission band of the doped dye. For the SWA waveguide devices, furthermore, the active waveguide core is essentially coupled with a fiber port for optical input. Owing to these advantages, an experimental configuration for the optical end pumping can be easily applied. The high absorption efficiency for the pumping light could be obtained in this pumping method. A remarkable lowering of the lasing threshold was observed. As the best results of this study, consequently, the lasing action under the optical pumping energy as low as 50 nJ was achieved. PMID:21164756

Yamashita, Kenichi; Ito, Masahiro; Sugimoto, Shuhei; Morishita, Takashi; Oe, Kunishige

2010-11-01

184

Optically pumped FIR lasers: Frequency and power measurements and laser magnetic resonance spectroscopy  

Microsoft Academic Search

Optically pumped FIR lasers are currently in use in both frequency metrology and laser magnetic resonance spectroscopy programs in the NBS Boulder labs. The laser for use in frequency metrology is a CW 71 ?m methyl alcohol waveguide laser with over 100 mW output for frequency synthesis. Another laser with an intracavity absorption cell for laser spectroscopy has been constructed

KENNETH M. EVENSON; DONALD A. JENNINGS; F. RUSSELL PETERSEN; JOHN A. MUCHA; JUAN J. JIMENEZ; R. M. Charlton; CARLETON J. HOWARD

1977-01-01

185

Diode-pumped continuous-wave Nd:glass laser  

NASA Technical Reports Server (NTRS)

The paper reports on diode-laser pumping of monolithic Nd:glass laser oscillators. End pumping with a single-stripe diode laser, a threshold of 2.2 mW, and a slope efficiency of 42 percent were observed on a 2-mm-long oscillator with a mode radius of 35 microns. The oscillator generated 2.5 mW of single-ended output power in many axial modes.

Kozlovsky, W. J.; Fan, T. Y.; Byer, R. L.

1986-01-01

186

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

NASA Astrophysics Data System (ADS)

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

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

1992-06-01

187

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

NASA Astrophysics Data System (ADS)

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

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

2014-10-01

188

Nuclear-Pumped Lasers. [efficient conversion of energy liberated in nuclear reactions to coherent radiation  

NASA Technical Reports Server (NTRS)

The state of the art in nuclear pumped lasers is reviewed. Nuclear pumped laser modeling, nuclear volume and foil excitation of laser plasmas, proton beam simulations, nuclear flashlamp excitation, and reactor laser systems studies are covered.

1979-01-01

189

Scaling of CO2TEA laser pumped roto-vibrational molecular lasers  

Microsoft Academic Search

Experimental results are presented which show that in CO2 laser pumped optically pumped roto-vibrational molecular lasers (OPMLs) it is the 'tail' rather than the 'spike' of the pump pulse which is important. The results of a model are described for pulse propagation in an absorbing medium. These results indicate that in one particular example for an OCS OPML (OCS equals

E. Armandillo; J. M. Green

1979-01-01

190

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

191

Diode-pumped lasers for ultra-high peak power  

NASA Astrophysics Data System (ADS)

The generation of the highest laser peak intensities at a high degree of system compactness can be achieved by combining modern diode-pump technologies with the chirped pulse amplification technique. In principle, the spectroscopic properties of the gain medium determine the scaling laws of both high output pulse energy and short pulse duration. Here we introduce a novel criterion classifying laser materials with respect to their ability to generate pulses of highest peak power in a diode-pumped solid state laser system. Furthermore, amplified spontaneous emission as well as laser damage issues affecting the efficiency and compactness of a laser amplifier system are discussed.

Siebold, M.; Hein, J.; Hornung, M.; Podleska, S.; Kaluza, M. C.; Bock, S.; Sauerbrey, R.

2008-03-01

192

Taming Random Lasers through Active Spatial Control of the Pump  

NASA Astrophysics Data System (ADS)

Active control of the spatial pump profile is proposed to exercise control over random laser emission. We demonstrate numerically the selection of any desired lasing mode from the emission spectrum. An iterative optimization method is employed, first in the regime of strong scattering where modes are spatially localized and can be easily selected using local pumping. Remarkably, this method works efficiently even in the weakly scattering regime, where strong spatial overlap of the modes precludes spatial selectivity. A complex optimized pump profile is found, which selects the desired lasing mode at the expense of others, thus demonstrating the potential of pump shaping for robust and controllable single mode operation of a random laser.

Bachelard, N.; Andreasen, J.; Gigan, S.; Sebbah, P.

2012-07-01

193

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

Microsoft Academic Search

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

H. R. Aldag; S. M. Dolotov; M. F. Koldunov; Ya V. Kravchenko; Aleksandr A. Manenkov; D. P. Pacheco; E. P. Ponomarenko; A. V. Reznichenko; G. P. Roskova; T. S. Tsekhomskaya

2000-01-01

194

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

195

Diode-array-pumped repetitively pulsed neodymium phosphate glass laser  

SciTech Connect

Repetitively pulsed generation (200 {mu}s, 40 Hz) was obtained in a neodymium phosphate glass laser pumped by a 870-nm diode array. The maximum slope lasing efficiency with respect to the optical pump energy equal to 13% is restricted by the factor ({approx}0.23) of active-medium filling by the mode field. By adjusting the laser cavity, the single-transverse mode regime, in particular, the generation of the TEM{sub 00} mode is obtained in the entire range of pump energies. (active media. lasers)

Bogatov, A P; Drakin, A E; Miftakhutdinov, D R; Starodub, A N [P. N. Lebedev Physics Institute, Russian Academy of Sciences, Moscow (Russian Federation); Mikaelyan, G T [Inject Research and Manufacturing Enterprise, Saratov (Russian Federation)

2008-09-30

196

Ultra-narrow-linewidth combined CW Ti:Sapphire/Dye laser for atom cooling and high-precision spectroscopy  

E-print Network

Ultra-narrow-linewidth combined CW Ti:Sapphire/Dye laser for atom cooling and high 37, k. 141, Novosibirsk, 630058, Russia ABSTRACT Presented is a new combined CW Ti:Sapphire/Dye laser-term output line width does not exceed 10 kHz for the Ti:Sapphire laser and amounts to 50 kHz for the Dye

Kobtsev, Sergei M.

197

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

198

Efficient laser performance of a cryogenic Yb:YAG laser pumped by fiber coupled 940 and 969?nm laser diodes  

NASA Astrophysics Data System (ADS)

Laser performance of Yb:YAG at different cryogenic temperatures pumped by a fiber coupled diode laser emitting at 940 and 969?nm were presented. The pump laser diode bandwidth, absorption bandwidth as well as absorption of the laser material at cryogenic temperatures play a vital role on laser performance. The laser threshold decreases and the output power and slope efficiency increase when cooled to cryogenic temperatures.

Jambunathan, V.; Miura, T.; T?snohlídková, L.; Lucianetti, A.; Mocek, T.

2015-01-01

199

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

200

New Concepts for Diode-Pumped Solid-State Lasers  

Microsoft Academic Search

Solid-state lasers are attractive sources of coherent radiation for various scientific and technological applications. But\\u000a the different fields of applications increasingly demand more powerful, efficient, and rugged lasers with higher beam quality.\\u000a Hence, at present a new generation of laser systems, based on diode lasers, has begun to dominate. Through replacement of\\u000a the discharge lamps formerly used as pump sources

Andreas Tuennermann; Holger Zellmer; Wolfram Schoene; Adolf Giesen; Karsten Contag

2000-01-01

201

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

202

First-order-like transition for colored saturation models of dye lasers: Effects of quantum noise  

NASA Astrophysics Data System (ADS)

A multidimensional form of the unified colored-noise approximation is applied to obtain the Fokker-Planck equation for intensity distributions of dye-laser models simultaneously driven by colored pump noise and quantum noise. The stationary intensity distributions (SID's) of these models are calculated. The first-order-like transitions (FOLT's) of the models are studied and compared. With the help of the combination of Sturm's theorem and Descarte's rule of signs, the following conclusions on the FOLT are obtained. (1) In the limit of white pump noise (the correlation time of the pump noise ?=0), the FOLT disappears for the colored loss-noise model with saturation whereas it does not disappear for the colored gain-noise model. (2) The dependence of the FOLT on ? is intensely affected by the quantum noise. If quantum noise is neglected, the first critical curve which separates the regions of single extremum and double extrema of the SID does not change with ?. However, when the quantum noise is considered, the first critical curve does change with ?. (3) When ?-->?, the area of region II in which the SID varies monotonically contracts and tends to zero. Therefore the FOLT disappears in the models. (4) It is found that when the strength of the quantum noise P varies (? is fixed), the critical curves also change.

Li, Cao; da-Jin, Wu; Ling, Lin

1994-01-01

203

600-W lamp pumped CW Nd:YAG laser  

NASA Astrophysics Data System (ADS)

A lamp pumped CW Nd:YAG laser is presented in this paper for the requirement of industrial application. The main factors, which affect output power and beam quality of high power solid-state laser module, are theoretically analyzed. Total electro-optics efficiency of lamp pumped Nd:YAG crystal as high as 4.0% is obtained, and output power is higher than 647 W with beam parameter product 22 mm·mrad.

Li, Qiang; Wang, Zhimin; Wang, Zhiyong; Yu, Zhensheng; Lei, Hong; Guo, Jiang; Li, Gang; Zuo, Tiechuan

2003-09-01

204

Quantum mechanical features of optically pumped CW FIR lasers  

NASA Technical Reports Server (NTRS)

Quantum mechanical predictions for the gain of an optically pumped CW FIR laser are presented for cases in which one or both of the pump and FIR transitions are pressure or Doppler broadened. The results are compared to those based on the rate equation model. Some of the quantum mechanical predictions are verified in CH3OH.

Seligson, D.; Leite, J. R. R.; Sanchez, A.; Feld, M. S.; Ducloy, M.

1977-01-01

205

Nuclear pumped lasers: Advantages of O2 (1 delta)  

NASA Technical Reports Server (NTRS)

Nuclear pumped laser technology was evaluated as a possible future weapons contender. It was determined that in order to become a primary weapon the following engineering problems must be solved: shielding, heat dissipation, high efficiency fixed focus pumping, good beam quality, and thermal blooming.

Taylor, J. J.

1979-01-01

206

Feasibility of supersonic diode pumped alkali lasers: Model calculations  

NASA Astrophysics Data System (ADS)

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.

2013-04-01

207

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

208

A Modular Control Platform for a Diode Pumped Alkali Laser  

NASA Astrophysics Data System (ADS)

Many of the difficulties of creating compact, high power laser systems can be overcome if the heat dissipating properties of chemical lasers can be combined with the efficiency of diode lasers. Recently, the novel idea of using solid state diode lasers to pump gaseous gain media, such as is done in diode pumped alkali lasers (DPALs), has been proposed and early experiments have shown promising results. However, a number of technical issues need to be overcome to realize high output power from these lasers. In order to achieve higher power, the efficiency of coupling between pump laser energy and the chemical cell must be increased, and eventually multiple high power diode pumps must be combined and synchronized so that their energy can pump the chemical cell. Additionally, an inter-cavity adaptive optics system may be a requirement to be able to propagate these lasers with high efficiency. DPAL systems are complex and require a significant amount of data fusion and active feedback to control and optimize their performance. There are a wide range of components including pump lasers, gain cells and monitoring points needed to study and refine the overall laser system. In support of this dynamic development environment, we have developed a hardware framework using commercial off the shelf (COTS) components which supports the rapid assembly of functional system blocks into a cohesive integrated system. Critical to this system are a simple communication protocol, industry standard communication pipes (USB, Bluetooth, etc), and flexible high level scripting. Simplifying the integration process has the benefit of allowing flexible "on the fly" modifications to adapt the system as needed and enhance available functionality. The modular nature of the architecture allows scalability and adaptability as more pieces are added to the system. Key components of this system are demonstrated for selected portions of a DPAL system using a USB backbone.

Shapiro, J.; Teare, S.

209

Development and characterization of Yb-Er laser glass for high average power laser diode pumping  

Microsoft Academic Search

.   A new strong erbium laser glass (SELG) based on a boro-alumo-phosphate composition is reported. We discuss the synthesis and\\u000a chemical properties together with spectroscopic and thermo-mechanical data. The new glass composition shows excellent laser\\u000a performance and withstands high-average power pump radiation. We present laser results at 1.54 ?m from flashlamp and laser\\u000a pumping. In tests with laser-diode pumped Q-switched Er-Yb

G. Karlsson; F. Laurell; J. Tellefsen; B. Denker; B. Galagan; V. Osiko; S. Sverchkov

2002-01-01

210

Four-Pass Coupler for Laser-Diode-Pumped Solid-State Laser  

NASA Technical Reports Server (NTRS)

A four-pass optical coupler affords increased (in comparison with related prior two-pass optical couplers) utilization of light generated by a laser diode in side pumping of a solid-state laser slab. The original application for which this coupler was conceived involves a neodymium-doped yttrium aluminum garnet (Nd:YAG) crystal slab, which, when pumped by a row of laser diodes at a wavelength of 809 nm, lases at a wavelength of 1,064 nm. Heretofore, typically, a thin laser slab has been pumped in two passes, the second pass occurring by virtue of reflection of pump light from a highly reflective thin film on the side opposite the side through which the pump light enters. In two-pass pumping, a Nd:YAG slab having a thickness of 2 mm (which is typical) absorbs about 84 percent of the 809-nm pump light power, leaving about 16 percent of the pump light power to travel back toward the laser diodes. This unused power can cause localized heating of the laser diodes, thereby reducing their lifetimes. Moreover, if the slab is thinner than 2 mm, then even more unused power travels back toward the laser diodes. The four-pass optical coupler captures most of this unused pump light and sends it back to the laser slab for two more passes. As a result, the slab absorbs more pump light, as though it were twice as thick. The gain and laser cavity beam quality of a smaller laser slab in conjunction with this optical coupler can thus be made comparable to those of a larger two-pass-pumped laser slab.

Coyle, Donald B.

2008-01-01

211

Passively Q-switched side pumped monolithic ring laser  

NASA Technical Reports Server (NTRS)

Disclosed herein are systems and methods for generating a side-pumped passively Q-switched non-planar ring oscillator. The method introduces a laser into a cavity of a crystal, the cavity having a round-trip path formed by a reflection at a dielectrically coated front surface, a first internal reflection at a first side surface of the crystal at a non-orthogonal angle with the front, a second internal reflection at a top surface of the crystal, and a third internal reflection at a second side surface of the crystal at a non-orthogonal angle with the front. The method side pumps the laser at the top or bottom surface with a side pump diode array beam and generates an output laser emanating at a location on the front surface. The design can include additional internal reflections to increase interaction with the side pump. Waste heat may be removed by mounting the crystal to a heatsink.

Li, Steven X. (Inventor)

2012-01-01

212

The ballistic method of pumping solid-state lasers  

E-print Network

The ballistic method for obtaining a dense radiating plasma and the possibilities of using this method to pump solid-state lasers are investigated. The plasma was obtained experimentally by heating the working gas in a ballistic plasmatron. A vortex chamber is proposed for transferring energy into the plasmatron - laser system.

Volov, D B

2013-01-01

213

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

214

Capacitive-discharge-pumped copper bromide vapour laser  

SciTech Connect

A copper bromide vapour laser pumped by a high-frequency capacitive discharge is developed. It is shown that, by using of a capacitive discharge, it is possible to built a sealed off metal halide vapour laser of a simple design allowing the addition of active impurities into the working medium. (letters)

Sukhanov, V B; Fedorov, V F; Troitskii, V O [Institute of Atmospheric Optics, Siberian Branch, Russian Academy of Sciences, Tomsk (Russian Federation); Gubarev, F A; Evtushenko, Gennadii S [Tomsk Polytechnical University, Tomsk (Russian Federation)

2007-07-31

215

Millennia V Diode-Pumped, CW Visible Laser  

E-print Network

Millennia V Diode-Pumped, CW Visible Laser User's Manual The Solid-State Laser Company 1335 Terra and service and includes a replacement parts list and a list of world-wide Spectra-Physics service centers you guide your Spectra-Physics field service engineer to the source of any problems. Do not attempt repairs

Kleinfeld, David

216

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

E-print Network

Abstract- The reliability and lifetime demanded by spacebased 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.

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

217

Diode-pumped solid state laser for inertial fusion energy  

SciTech Connect

The authors evaluate the prospect for development of a diode-pumped solid-state-laser driver in an inertial fusion energy power plant. Using a computer code, they predict that their 1 GWe design will offer electricity at 8.6 cents/kW {center_dot} hr with the laser operating at 8.6% efficiency and the recycled power level at 31%. The results of their initial subscale experimental testbed of a diode-pumped solid state laser are encouraging, demonstrating good efficiencies and robustness.

Payne, S.A.; Krupke, W.F.; Orth, C.D. [and others

1994-11-01

218

Improving Reliability of High Power Quasi-CW Laser Diode Arrays for Pumping Solid State Lasers  

NASA Technical Reports Server (NTRS)

Most Lidar applications rely on moderate to high power solid state lasers to generate the required transmitted pulses. However, the reliability of solid state lasers, which can operate autonomously over long periods, is constrained by their laser diode pump arrays. Thermal cycling of the active regions is considered the primary reason for rapid degradation of the quasi-CW high power laser diode arrays, and the excessive temperature rise is the leading suspect in premature failure. The thermal issues of laser diode arrays are even more drastic for 2-micron solid state lasers which require considerably longer pump pulses compared to the more commonly used pump arrays for 1-micron lasers. This paper describes several advanced packaging techniques being employed for more efficient heat removal from the active regions of the laser diode bars. Experimental results for several high power laser diode array devices will be reported and their performance when operated at long pulsewidths of about 1msec will be described.

Amzajerdian, Farzin; Meadows, Byron L.; Baker, Nathaniel R.; Barnes, Bruce W.; Baggott, Renee S.; Lockard, George E.; Singh, Upendra N.; Kavaya, Michael J.

2005-01-01

219

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

220

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

221

CW theory of a laser diode-pumped two-manifold solid state laser  

Microsoft Academic Search

We develop a general plane wave theory for cw diode-pumped solid state lasers which is valid for arbitrary saturation and outcoupling. Our model is based on the steady state rate equations for a two-manifold system coupled to the growth of the laser field and the depletion of the pump. This model is entirely analytic and predicts: a linear photon flux

P. Peterson; A. Gavrielides; P. M. Sharma

1994-01-01

222

Diode-pumped thin disk 15% Tm:KYW laser  

NASA Astrophysics Data System (ADS)

We demonstrate high-efficient CW thin disk 15%Tm:KYW laser pumped by a 20W CW laser diode bar at 803nm. Three 15%Tm:KYW b-cut disks of 200, 250 and 300?m thickness are tested, with the maximal laser output being of 4.9W at ~1.9?m. Slope and optical-to-optical conversion efficiencies are reported as well.

Vatnik, S. M.; Vedin, I. A.; Pavljuk, A. A.

2007-06-01

223

Revisiting of LED pumped bulk laser: first demonstration of Nd:YVO4 LED pumped laser.  

PubMed

We describe here what is, to the best of our knowledge, the first LED pumped Nd:YVO4 laser. Near-IR LED arrays with a wavelength centered close to 850 nm were used to pump transversely the crystal. By pulsing LEDs, with a duration of the order of the laser transition lifetime, we obtained sufficient pump intensities to reach the laser threshold. At a frequency of 250 Hz, we obtained an output energy of 40 ?J at 1064 nm for an input pump energy of 7.4 mJ, which corresponds to an optical efficiency of 0.5%. Experimental results of small signal gain are compared with theoretical analysis. PMID:25490664

Barbet, Adrien; Balembois, François; Paul, Amandine; Blanchot, Jean-Philippe; Viotti, Anne-Lise; Sabater, Jacques; Druon, Frédéric; Georges, Patrick

2014-12-01

224

CONTROL OF LASER RADIATION PARAMETERS: Features of emission from a submillimeter laser under intense optical pumping  

NASA Astrophysics Data System (ADS)

The emission of a submillimeter laser pumped by a high-power (up to ~ 1 kW) CO2 laser is studied. It is found that lasing of CH2F2 molecules saturates at the pump power ~350 W. A delay of submillimeter lasing depending on the gas pressure in the active medium and the pump intensity is observed. The possibility of a rapid tuning (in about 1 ms) of the submillimeter laser emission by scanning the emission from the CO2 laser is demonstrated experimentally.

Grachev, Gennadii N.; Zaikovskii, Ivan V.; Zakharyash, Valerii F.; Klementyev, Vasilii M.; Smirnov, A. L.

2002-05-01

225

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

E-print Network

Continuous-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- ward the development of solid-state lasers. Indeed, bulk solid-state lasers including bulk doped

Paris-Sud XI, Université de

226

Infantile hemangioma: pulsed dye laser versus surgical therapy  

NASA Astrophysics Data System (ADS)

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

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

2014-05-01

227

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

228

High-power diode-pumped cryogenically cooled Yb:CaF2 laser  

E-print Network

, in the past few years, among the most promising laser materials for high- energy/high-power diode-pumped laserHigh-power diode-pumped cryogenically cooled Yb:CaF2 laser with extremely low quantum defect S March 30, 2011 (Doc. ID 143643); published April 27, 2011 High-power diode-pumped laser operation at 992

229

High Power 938nm Cladding Pumped Fiber Laser  

SciTech Connect

We have developed a Nd:doped cladding pumped fiber amplifier, which operates at 938nm with greater than 2W of output power. The core co-dopants were specifically chosen to enhance emission at 938nm. The fiber was liquid nitrogen cooled in order to achieve four-level laser operation on a laser transition that is normally three level at room temperature, thus permitting efficient cladding pumping of the amplifier. Wavelength selective attenuation was induced by bending the fiber around a mandrel, which permitted near complete suppression of amplified spontaneous emission at 1088nm. We are presently seeking to scale the output of this laser to 10W. We will discuss the fiber and laser design issues involved in scaling the laser to the 10W power level and present our most recent results.

Dawson, J; Beach, R; Brobshoff, A; Liao, Z; Payne, S; Pennington, D; Taylor, L; Hackenberg, W; Bonaccini, D

2002-12-26

230

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

231

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

232

Patterned Block-Copolymer-Silica Mesostructures as Host Media for the Laser Dye Rhodamine 6G  

E-print Network

Patterned Block-Copolymer-Silica Mesostructures as Host Media for the Laser Dye Rhodamine 6G Gernot support and cladding. For the structure-directing block copolymer surfactants used, (EO)20(PO)70(EO)20 (P

Yang, Peidong

233

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

234

Continuous-wave SrMoO4 intracavity Raman laser pumped using a disk laser  

Microsoft Academic Search

The use of disk lasers to pump continuous-wave (cw) intracavity Raman lasers is discussed with a view to power scaling these devices via improved thermal management. Preliminary results for a Nd:YVO4\\/SrMoO4 Raman laser in this geometry are reported. An output power of 295 mW at the 1st Stokes wavelength of 1175 nm was obtained for 13.2 W absorbed pump power

Gerald M Bonner; Huaijin Zhang; Jiyang Wang; Alan J Kemp; Helen M Pask

2011-01-01

235

LaRC results on nuclear pumped noble gas lasers  

NASA Technical Reports Server (NTRS)

The recent experiment and theoretical results obtained for noble gas nuclear laser systems are presented. It is shown that the noble gas lasers are among the easiest systems to pump by nuclear excitation and as a result, all of the noble gases except He have lased under nuclear excitation. The noble gas systems are not ideal for high-power applications but they do give valuable insight into the operation and pumping mechanisms associated with nuclear lasers. At present, the Ar-Xe system is the best noble gas candidate for (U-235)F6 pumping. It appears that the quenching of Ar-Xe lasing is a result of the fluorine and not the uranium or fission fragments themselves. Thus, to achieve lasing with UF6, a fluorine compatible system must be found.

Deyoung, R. J.

1979-01-01

236

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

237

Adaptive pumping for spectral control of random lasers  

NASA Astrophysics Data System (ADS)

A laser is not necessarily a sophisticated device: pumping an amplifying medium randomly filled with scatterers makes a perfectly viable `random laser'. The absence of mirrors greatly simplifies laser design, but control over the emission wavelength and directionality is lost, seriously hindering prospects for this otherwise simple laser. Recently, we proposed an approach to tame random lasers, inspired by coherent light control in complex media. Here, we implement this method in an optofluidic random laser where modes are spatially extended and overlap, making individual mode selection impossible, a priori. We show experimentally that control over laser emission can be regained even in this extreme case. By actively shaping the optical pump within the random laser, single-mode operation at any selected wavelength is achieved with spectral selectivity down to 0.06 nm and more than 10 dB side-lobe rejection. This method paves the way towards versatile tunable and controlled random lasers as well as the taming of other laser sources.

Bachelard, Nicolas; Gigan, Sylvain; Noblin, Xavier; Sebbah, Patrick

2014-06-01

238

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

239

A cladding-pumped, tunable holmium doped fiber laser.  

PubMed

We present a tunable, high power cladding-pumped holmium doped fiber laser. The laser generated >15 W CW average power across a wavelength range of 2.043 - 2.171 ?m, with a maximum output power of 29.7 W at 2.120 ?m. The laser also produced 18.2 W when operating at 2.171 µm. To the best of our knowledge this is the highest power operation of a holmium doped laser at a wavelength >2.15 µm. We discuss the significance of background losses and fiber design for achieving efficient operation in holmium doped fibers. PMID:24514352

Simakov, Nikita; Hemming, Alexander; Clarkson, W Andrew; Haub, John; Carter, Adrian

2013-11-18

240

Pump and probe spectroscopy with continuous wave quantum cascade lasers  

SciTech Connect

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.

Kirkbride, James M. R.; Causier, Sarah K.; Dalton, Andrew R.; Ritchie, Grant A. D., E-mail: grant.ritchie@chem.ox.ac.uk [Department of Chemistry, Physical and Theoretical Chemistry Laboratory, The University of Oxford, South Parks Road, Oxford (United Kingdom)] [Department of Chemistry, Physical and Theoretical Chemistry Laboratory, The University of Oxford, South Parks Road, Oxford (United Kingdom); Weidmann, Damien [Space Science and Technology Department, STFC Rutherford Appleton Laboratory, Harwell Oxford Campus, Didcot OX11 0QX (United Kingdom)] [Space Science and Technology Department, STFC Rutherford Appleton Laboratory, Harwell Oxford Campus, Didcot OX11 0QX (United Kingdom)

2014-02-07

241

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

242

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

243

Electron beam pumped KrF lasers for fusion energy  

NASA Astrophysics Data System (ADS)

In this paper, we describe the development of electron beam pumped KrF lasers for inertial fusion energy. KrF lasers are an attractive driver for fusion, on account of their demonstrated very high beam quality, which is essential for reducing imprint in direct drive targets; their short wavelength (248 nm), which mitigates the growth of plasma instabilities; and their modular architecture, which reduces development costs. In this paper we present a basic overview of KrF laser technology as well as current research and development in three key areas: electron beam stability and transport; KrF kinetics and laser propagation; and pulsed power. The work will be cast in context of the two KrF lasers at the Naval Research Laboratory, The Nike Laser (5 kJ, single shot), and The Electra Laser (400-700 J repetitively pulsed).

Sethian, J. D.; Friedman, M.; Giuliani, J. L.; Lehmberg, R. H.; Obenschain, S. P.; Kepple, P.; Wolford, M.; Hegeler, F.; Swanekamp, S. B.; Weidenheimer, D.; Welch, D.; Rose, D. V.; Searles, S.

2003-05-01

244

Increasing pumping efficiency by using gradient-doped laser crystals  

NASA Astrophysics Data System (ADS)

Investigations of a new class of optical materials with functional nonuniform distribution of optical dopant are continued. Longitudinal pumping and heat release in active elements with a gradient distribution of optical centers are simulated. It is shown that, for a given length of the laser element, pumping efficiency remains at a stably high level upon variation of its power density for different gradients of concentration of activators. It is demonstrated that, in addition to a high level of optical pumping efficiency, the temperature profile in the active medium becomes smoother.

Stroganova, E. V.; Galutskiy, V. V.; Tkachev, D. S.; Nalbantov, N. N.; Tsema, A. A.; Yakovenko, N. A.

2014-12-01

245

Nonlinear fibre-optic devices pumped by semiconductor disk lasers  

SciTech Connect

Semiconductor disk lasers offer a unique combination of characteristics that are particularly attractive for pumping Raman lasers and amplifiers. The advantages of disk lasers include a low relative noise intensity (-150 dB Hz{sup -1}), scalable (on the order of several watts) output power, and nearly diffraction-limited beam quality resulting in a high ({approx}70 % - 90 %) coupling efficiency into a single-mode fibre. Using this technology, low-noise fibre Raman amplifiers operating at 1.3 {mu}m in co-propagation configuration are developed. A hybrid Raman-bismuth doped fibre amplifier is proposed to further increase the pump conversion efficiency. The possibility of fabricating mode-locked picosecond fibre lasers operating under both normal and anomalous dispersion is shown experimentally. We demonstrate the operation of 1.38-{mu}m and 1.6-{mu}m passively mode-locked Raman fibre lasers pumped by 1.29-{mu}m and 1.48-{mu}m semiconductor disk lasers and producing 1.97- and 2.7-ps pulses, respectively. Using a picosecond semiconductor disk laser amplified with an ytterbium-erbium fibre amplifier, the supercontinuum generation spanning from 1.35 {mu}m to 2 {mu}m is achieved with an average power of 3.5 W. (invited paper)

Chamorovskiy, A Yu; Okhotnikov, Oleg G [Optoelectronics Research Center, Tampere University of Technology, Tampere (Finland)

2012-11-30

246

Terahertz emission in organic crystals pumped by conventional laser wavelength  

NASA Astrophysics Data System (ADS)

Intense Terahertz radiation in organic crystals is typically generated by optical rectification of short wavelength infrared femtosecond lasers between 1.3 and 1.5 ?m. In this wavelength range high energy ultrashort pump sources are hardly available. Here we present results on powerful THz generation by using DAST and DSTMS pumped directly by the widely used and well-established Ti:sapphire laser technology, emitting at 0.8 ?m. This approach enables straightforward THz generation by optical rectification. We present systematic studies on nIR-to-THz conversion efficiency, damage threshold, and on the emitted THz spectrum and field strength.

Vicario, Carlo; Monoszlai, Balazs; Ruiz, Blanca; Jazbinsek, Mojca; Medrano, Carolina C.; Hauri, Christoph P.

2014-03-01

247

Diode-Pumped Mode-Locked LiSAF Laser  

SciTech Connect

Under this contract we have developed Cr{sup 3+}:LiSrAlF{sub 6} (Cr:LiSAF, LiSAF) mode-locked lasers suitable for generation of polarized electrons for CEBAF. As 670 nm is an excellent wavelength for optical pumping of Cr:LiSAF, we have used a LIGHTWAVE developed 670 nm diode pump module that combines the output of ten diode lasers and yields approximately 2 Watts of optical power. By the use of a diffraction limited pump beam however, it is possible to maintain a small mode size through the length of the crystal and hence extract more power from Cr:LiSAF laser. For this purpose we have developed a 1 Watt, red 660nm laser (LIGHTWAVE model 240R) which serves as an ideal pump for Cr:LiSAF and is a potential replacement of costly and less robust krypton laser. This new system is to compliment LIGHTWAVE Series 240, and is currently being considered for commercialization. Partially developed under this contract is LIGHTWAVEs product model 240 which has already been in our production lines for a few months and is commercially available. This laser produces 2 Watts of output at 532 nm using some of the same technology developed for production of the 660nm red system. It is a potential replacement for argon ion lasers and has better current and cooling requirements and is an excellent pump source for Ti:Al{sub 2}O{sub 3}. Also, as a direct result of this contract we now have the capability of commercially developing a mode-locked 100MHz Cr:LiSAF system. Such a laser could be added to our 100 MHz LIGHTWAVE Series 131. The Series 131 lasers provide pico second pulses and were originally developed under another DOE SBIR. Both models of LIGHTWAVE Series 240 lasers, the fiber coupled pump module and the 100MHz LiSAF laser of Series 131 have been partially developed under this contract, and are commercially competitive products.

None

1996-02-01

248

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

249

Development of a nanosecond-laser-pumped Raman amplifier for short laser pulses in plasma  

E-print Network

of solid-state optics. The amplifica- tion of short laser pulses is achieved by energy transfer from a longDevelopment of a nanosecond-laser-pumped Raman amplifier for short laser pulses in plasma Y. Ping,1 December 2009 Progress on developing a plasma amplifier/compressor based on stimulated Raman scattering

250

LED pumped Nd:YAG laser development program  

NASA Technical Reports Server (NTRS)

The results of a development program for light emitting diode (LED) pumped Nd:YAG lasers are described. An index matching method to increase the coupling efficiency of the laser is described. A solid glass half-cylinder of 5.0 by 5.6 centimeters was used for index matching and also as a pumping cavity reflector. The laser rods were 1.5 by 56 millimeters with dielectric coatings on both end surfaces. The interfaces between the diode array, glass cylinder, and laser rod were filled with viscous fluid of refractive index n = 1.55. Experiments performed with both the glass cylinder and a gold coated stainless steel reflector of the same dimensions under the same operating conditions indicate that the index matching cylinder gave 159 to 200 percent improvement of coupling efficiency over the metal reflector at various operating temperatures.

Farmer, G. I.; Kiang, Y. C.; Lynch, R. J.

1973-01-01

251

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

252

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. PMID:25324655

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

2014-01-01

253

Development of a dual-wavelength dye-laser system for the UV and its application to simultaneous multi-element detection  

NASA Astrophysics Data System (ADS)

In this paper, the design and performance characteristics of a pulsed tunable dye laser system for the simultaneous generation of two UV wavelengths are presented. The system is composed of an oscillator and an amplifier stage, pumped by the second harmonic of a commercial Nd:YAG laser. Dual-wavelength operation is achieved with one additional tuning mirror introduced to the prism expanded grazing incidence oscillator. The two obtained wavelengths are independently tunable, their separation is only limited by the gain profile of the dye. Both wavelengths are frequency doubled by Second-Harmonic Generation (SHG) in two KDP or BBO crystals. Performance characteristics such as bandwidth, efficiency, tuning range and wavelength separation are reported. As application two such systems are used for the simultaneous detection of the four elements cadmium, nickel, manganese and lead by Laser-Excited Atomic Fluorescence Spectrometry in a graphite furnace (ETA-LEAFS).

Schütz, M.; Heitmann, U.; Hese, A.

1995-10-01

254

Cladding for transverse-pumped solid-state laser  

NASA Technical Reports Server (NTRS)

In a transverse pumped, solid state laser, a nonabsorptive cladding surrounds a gain medium. A single tranverse mode, namely the Transverse Electromagnetic (TEM) sub 00 mode, is provided. The TEM sub 00 model has a cross sectional diameter greater than a transverse dimension of the gain medium but less than a transverse dimension of the cladding. The required size of the gain medium is minimized while a threshold for laser output is lowered.

Byer, Robert L. (inventor); Fan, Tso Y. (inventor)

1989-01-01

255

Further development of high-power pump laser diodes  

Microsoft Academic Search

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

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

2003-01-01

256

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.

257

Deformation of partially pumped active mirrors for high average-power diode-pumped solid-state lasers.  

PubMed

We discuss the deformation of a partially pumped active mirror amplifier as a free standing disk, as implemented in several laser systems. We rely on the Lucia laser project to experimentally evaluate the analytical and numerical deformation models. PMID:21643092

Albach, Daniel; LeTouzé, Geoffroy; Chanteloup, Jean-Christophe

2011-04-25

258

Infrared and far-infrared laser emissions from a TE CO2 laser pumped NH3 gas  

Microsoft Academic Search

In this paper, infrared (IR) and far-infrared (FIR) laser emissions from a TE CO2 laser pumped NH3 gas are reported. 8 IR laser emissions near the wavelength of 12 mum were observed by using 4 different CO2 laser lines for the pumping. 3 IR laser emissions in P-branch of vibrational-rotational band (nu2 --> G) oscillated simultaneously in two pumping cases,

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

1978-01-01

259

Investigations of laser pumped gas cell atomic frequency standard  

NASA Technical Reports Server (NTRS)

The performance characteristics of a rubidium gas cell atomic frequency standard might be improved by replacing the standard rubidium discharge lamp with a single mode laser diode. Aspects of the laser pumped gas cell atomic clock studied include effects due to laser intensity, laser detuning, and the choice of the particular atomic absorption line. Results indicate that the performance of the gas cell clock may be improved by judicious choice of the operating parameters of the laser diode. The laser diode also proved to be a valuable tool in investigating the operation of the conventional gas cell clock. Results concerning linewidths, the light shift effect and the effect of isotopic spin exchange in the conventional gas cell clock are reported.

Volk, C. H.; Camparo, J. C.; Fueholz, R. P.

1982-01-01

260

Random distributed feedback Raman fiber laser with polarized pumping  

NASA Astrophysics Data System (ADS)

In this letter, the polarization properties of a random fiber laser operating via Raman gain and random distributed feedback owing to Rayleigh scattering are investigated for the first time. Using polarized pump, the partially polarized generation is obtained with a generation spectrum exhibiting discrete narrow spectral features contrary to the smooth spectrum observed for the depolarized pump. The threshold, output power, degree of polarization and the state of polarization (SOP) of the lasing can be significantly influenced by the SOP of the pump. Fine narrow spectral components are also sensitive to the SOP of the pump wave. Furthermore, we found that random lasing’s longitudinal power distributions are different in the case of polarized and depolarized pumping that results in considerable reduction of the generation slope efficiency for the polarized radiation. Our results indicate that polarization effects play an important role on the performance of the random fiber laser. This work improves the understanding of the physics of random lasing in fibers and makes a step forward towards the establishment of the vector model of random fiber lasers.

Wu, H.; Wang, Z. N.; Churkin, D. V.; Vatnik, I. D.; Fan, M. Q.; Rao, Y. J.

2015-01-01

261

Electrically pumped mode-locked vertical-cavity semiconductor lasers.  

PubMed

We demonstrate what is to our knowledge the first electrically pumped mode-locked vertical-cavity surfaceemitting laser. The lasing threshold current is 15 mA with a 1% output coupler. The output pulse width is 80 ps at a repetition rate of 1 GHz. PMID:19829453

Jiang, W; Shimizu, M; Mirin, R P; Reynolds, T E; Bowers, J E

1993-11-15

262

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

263

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

264

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

265

Scaling Studies of Blackbody-Pumped Carbon-Dioxide Lasers Using Gaussian and Waveguide Cavities  

Microsoft Academic Search

A large scale pulsed laser system with heated tantalum foils as the blackbody pumping source was built in the laboratory. A deeper understanding of the physics and the scaling factors of the blackbody pumped CO _2 laser has been achieved through parametric scaling studies using this system. Numerical analysis is also performed for computing pumping power and laser gain. Theoretical

Jim Jih-Chyun Chang

1989-01-01

266

Scaling studies of blackbody-pumped CO sub 2 lasers using gaussian and waveguide cavities  

Microsoft Academic Search

A large scale pulsed laser system with heated tantalum foils as the blackbody pumping source was built in the laboratory. A deeper understanding of the physics and the scaling factors of the blackbody pumped COâ laser has been achieved through parametric scaling studies using this system. Numerical analysis is also performed for computing pumping power and laser gain. Theoretical analysis

1989-01-01

267

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

NASA Astrophysics Data System (ADS)

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

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

2014-05-01

268

New materials for diode laser pumping of solid-state lasers  

Microsoft Academic Search

The authors review recent progress in the development of new materials for III-V semiconductor diode lasers useful for pumping solid-state lasers. All of the diode lasers discussed are grown on GaAs substrates. Particular emphasis is placed on the performance and reliability of high-CW-power strained-layer InGaAs-AlGaAs diode lasers emitting in the wavelength range between 0.87 and 1.1 ?m, improved resistance to

C. A. Wang; S. H. Groves

1992-01-01

269

CW submillimeter wave laser pumped by an RF-excited CO2 waveguide laser  

Microsoft Academic Search

Optical pumping of a submillimeter wave (SMMW) laser with a relatively compact continuous wave CO2 waveguide laser is reported. The CO2 laser beam is directed into the SMMW cavity through a 1.5-mm hole in the mirror of the SMMW laser, which is an unoptimized hole-coupled resonator with a 90-cm long metal waveguide. Part of the beam is reflected off the

M. S. Tobin

1981-01-01

270

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

271

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

272

Development of distributed feedback dye lasers for generation of high-power 193 nm excimer laser short pulses  

Microsoft Academic Search

The combination of picosecond dye lasers, nonlinear mixing in crystals, and excimer amplifiers offers an attractive way to generate intense diffraction-limited pulses throughout the ultraviolet region. However, it is difficult to generate 193 nm seed pulses because this wavelength cannot be obtained by second harmonic generation method in any known crystals. The thesis will describe a laser system which efficiently

Yifeng Cui

1993-01-01

273

The spectral characteristics of CW dye laser emission with intracavity absorption by a gaseous medium  

Microsoft Academic Search

The spectral characteristics of emission from a CW dye laser, which is locked to atomic absorption lines in a gas discharge, have been investigated experimentally. The observed behavior of the laser spectrum at different output power levels and cavity tunings confirmed a conclusion concerning the dominant role of the absorbing medium in the frequency locking mechanism. It is shown that

M. V. Danileiko; A. M. Negriiko; E. G. Udovitskaia; V. M. Khodakovskii; L. P. Iatsenko

1985-01-01

274

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 several solvent viscosities. A decrease on the relative fluctuations amplitude as the solvent viscosity, the achieved orientation during the time of radia- tion of the laser pulse will depend on the solvent viscosity

Rey Juan Carlos, Universidad

275

Solid-state laser-pumped high-power electric-discharge HF laser  

SciTech Connect

We report the possibility of creating high-power nonchain electric-discharge HF lasers with an all-solid-state pump source. The maximum energy stored in the pump source capacitors based on solid-state FID-switches is 990 J for the open-circuit voltage of 240 kV. The pulse energy of 30 J is obtained in the hydrogen-containing SF{sub 6} mixture at the electric efficiency of the order of 3%. (lasers)

Velikanov, S D; Garanin, Sergey G; Kodola, B E; Komarov, Yu N; Shchurov, V V [Russian Federal Nuclear Center - The All-Russian Research Institute of Experimental Physics, Sarov, Nizhnii Novgorod region (Russian Federation); Efanov, V M; Efanov, M V; Yarin, P M ['FID Technology' Research and Production Association, St.Petersburg (Russian Federation); Kazantsev, S Yu; Kononov, I G; Firsov, K N [A M Prokhorov General Physics Institute, Russian Academy of Sciences, Moscow (Russian Federation); Domazhirov, A P; Podlesnykh, S V; Sivachev, A A

2010-08-03

276

Mode-locking of diode laser-pumped solid-state lasers  

Microsoft Academic Search

Mode-locked diode-pumped solid state lasers have become important sources for efficient and reliable short pulse generation. We review techniques for active mode-locking of diode-pumped lasers, highlighting techniques which have produced much shorter pulse durations than previous technologies and extended operating repetition rates to the several gigahertz regime. To achieve even shorter pulse durations a series of nonlinear passive mode-locking techniques

G. P. A. Malcolm; A. I. Ferguson

1992-01-01

277

Highly efficient passive Q switches for a neodymium laser based on thiopyrylotricarbocyanine dyes  

SciTech Connect

The spectral, photochemical and nonlinear optical properties of a group of thiopyrylotricarbocyanine dyes in a polyurethane matrix are studied and compared with well-known materials for passive Q-switching such as nickel BDN and BDNII complexes. Passive laser Q switches based on these dyes feature the high modulation efficiency (up to 76%) in neodymium lasers and high photochemical stability. It is shown that the service life of Q switches can be considerably increased by removing oxygen from a polymer matrix. (elements of laser setups)

Bezrodnyi, V I [Institute of Physics, National Academy of Sciences of Ukraine, Kiev (Ukraine); Derevyanko, Nadezhda A; Ishchenko, Aleksandr A; Kropachev, A V [Institute of Organic Chemistry, National Academy of Sciences of Ukraine, Kiev (Ukraine)

2009-01-31

278

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

279

Continuous-wave mode-locked optical parametric oscillator synchronously pumped by a diode-laser-pumped solid-state laser  

Microsoft Academic Search

Continuous-wave operation of a mode-locked optical parametric oscillator has been achieved with the use of an all-solid-state laser pump. The oscillator, based on a 5-mm-long KTP crystal, is synchronously pumped at 523.5 nm by a continuous train of picosecond pulses at 352 MHz obtained by frequency doubling the output of a CW mode-locked, diode-laser-pumped Nd:YLF laser in an external enhancement

M. Ebrahimzadeh; G. P. A. Malcolm; A. I. Ferguson

1992-01-01

280

Expansion cooled CO nuclear pumped laser  

NASA Technical Reports Server (NTRS)

The paper describes a series of experiments designed to investigate the performance of a fission fragment excited CO laser with gasdynamic cooling. The experiments use a wall source of fission fragments to provide excitation of CO or CO gas mixtures. A separate investigation examines the effects on vibrational excitation distribution of CO or CO gas mixtures with the addition of UF6.

Davis, J. F.; Bird, P. F.; Mansfield, C. R.; Helmick, H. H.

1979-01-01

281

Laser pumped superconductive energy storage system  

Microsoft Academic Search

A superconductive energy storage system comprising a magnetic field surrounding a superconducting coil having large currents circulating therein, cooling said coil to superconducting temperatures, starting said circulating current in said superconducting coil inductively by a small primer coil, transmitting additional energy into said energy storage system utilizing a laser beam, and retaining said energy in said energy storage system until

1983-01-01

282

Diode Pumped Solid State Laser Photoacoustic Spectrometer  

E-print Network

Abstract: Photoacoustic spectroscopy (PAS) is well-known for trace gas detection but has been hampered by the lack of a simple tunable infrared source. DPSS lasers offer this capability and enable a PAS sensor with superior performance. ©2000 Optical Society of America

Jeffrey S. Pilgrim; David S. Bomse

283

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

284

Lasers '87; Proceedings of the Tenth International Conference on Lasers and Applications, Lake Tahoe, NV, Dec. 7-11, 1987  

NASA Astrophysics Data System (ADS)

Various papers on lasers are presented. The general topics addressed include: laser physics and theory, VUV and X-ray lasers, excimer lasers, chemical lasers, nuclear pumped lasers, blue-green and metal-vapor lasers, dye lasers, solid-state lasers, semiconductor and diode lasers, CO2 lasers, FIR lasers, ultrafast phenomena, nonlinear phenomena, wave mixing and dynamic gratings, and phase conjugation. Also considered are: laser radars and remote sensing, adaptive optics and propagation, imaging, fiber optics, laser spectroscopy, laser dyes, lasers in medicine, optical devices and measuring technique, laser industrial applications, lasers in strategic defense.

Duarte, F. J.

285

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

NASA Astrophysics Data System (ADS)

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

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

1997-05-01

286

Pump and signal combiner for bi-directional pumping of all-fiber lasers and amplifiers.  

PubMed

We developed an all-fiber component with a signal feedthrough capable of combining up to 6 fiber-coupled multi-mode pump sources to a maximum pump power of 400 W at efficiencies in the range of 89 to 95%, providing the possibility of transmitting a high power signal in forward and in reverse direction. Hence, the fiber combiner can be implemented in almost any fiber laser or amplifier architecture. The complete optical design of the combiner was developed based on ray tracing simulations and confirmed by experimental results. PMID:23263048

Theeg, Thomas; Sayinc, Hakan; Neumann, Jörg; Overmeyer, Ludger; Kracht, Dietmar

2012-12-17

287

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

288

Fiber Raman laser and amplifier pumped by Nd3+:YVO4 solid state laser  

NASA Astrophysics Data System (ADS)

Pumping source is the key technology of fiber Raman amplifiers (FRA) which are important for ultra long haul and high bit rate dense wavelength division multiplexing (DWDM) systems. In this paper the research work of the project, "Fiber Raman Laser and Amplifier pumped by Nd3+:YVO4 Solid State Laser", supported by the National High-tech Program (863-program) of China is introduced, in which a novel 14xx nm pump module with fine characteristics of high efficiency, simplicity, compactness and low cost is researched and developed. A compact 1342 nm Nd3+:YVO4 diode pumped solid state laser (DPSSL) module is developed with the total laser power of 655mW and the slope efficiency of 42.6% pumped by a 2W 808nm laser diode (LD). A special C-lens fiber collimator is designed to couple the 1342nm laser beam into a piece of single mode fiber (SMF) and the coupling efficiency of 80% is reached. The specific 14xx nm output laser is generated from a single stage Raman resonator which includes a pair of fiber Bragg gratings and a piece of Germanic-silicate or Phospho-silicate fiber pumped by such DPSSL module. The slope efficiency for conversion from 1342 to 14xx nm radiation is 75% and the laser power is more than 300mW each. Finally, Raman gain experiments are carried out with 100km SMF. 100 nm bandwidth with 10dB on-off Raman gain and 1.1dB gain flatness is achieved by pumped at 1425, 1438, 1455 and 1490nm.

Liu, Deming; Zhang, Minming; Liu, Shuang; Nie, Mingju; Wang, Ying

2005-04-01

289

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

290

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

SciTech Connect

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

Sizykh, A G; Tarakanova, E A [Quantum Electronics Division, Krasnoyarsk State University, Krasnoyarsk (Russian Federation)

1998-12-31

291

Resonantly pumped room temperature Ho:LuVO? laser.  

PubMed

Spectroscopic characterization of a Ho:LuVO4 crystal grown by the Czochralski method has been performed, including the absorption and emission spectra. We demonstrate a 2 ?m room temperature Ho:LuVO4 laser, resonantly pumped by a 1.94 ?m Tm:YAP laser. By use of an output coupler with T=10% transmission, the Ho:LuVO4 laser generated continuous-wave output power of 2.5 W at 2074.18 nm, with a beam quality factor of Mx2=My2=1.3, for a total incident pump power of 19.4 W. The slope efficiency with respect to the pump power was 17.6%, and the optical-to-optical efficiency was 12.9%. Moreover, we obtained a Ho:LuVO4 laser that operated at 2073.77 and 2055.27 nm, by using different output couplers with transmissions of T=15 and 30%. PMID:25361346

Yao, B Q; Cui, Z; Duan, X M; Du, Y Q; Han, L; Shen, Y J

2014-11-01

292

Electric-discharge-pumped nitrogen ion laser  

NASA Technical Reports Server (NTRS)

The routine operation is described of an N2(+) laser oscillating on the first negative band system of N2(+) which is produced in a preionized transverse discharge device. The discharge design incorporates features which favor the efficient production of the excitation transfer reaction of He2(+) with N2. A capacitive discharge switched by means of a high-current grounded grid thyratron is used to meet the design requirement of a volumetric discharge in high-pressure gas mixtures where the electric discharge need not have an ultrafast rise time (greater than 10 nsec) but should be capable of transferring large quantities of stored electric energy to the gas. A peak power of 180 kW in an 8-nsec laser pulse was obtained with a 0.1% mixture of N2 in helium at a total pressure of 3 atm. The most intense laser oscillations were observed on the (0,1) vibrational transition at 427.8 microns.

Laudenslager, J. B.; Pacala, T. J.; Wittig, C.

1976-01-01

293

Measurement of liquid sheet using laser tagging method by photochromic dye  

NASA Astrophysics Data System (ADS)

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

Rosli, Nurrina Binti; Amagai, Kenji

2014-12-01

294

Loss measurements on laser-dye-doped and undoped unclad plastic optical fibers  

NASA Astrophysics Data System (ADS)

We present side induced fluorescence (SIF) results on laser dye doped unclad plastic optical fibers. The SIF data can be used to obtain optical loss spectra for the low loss region of the absorption tail of the laser dye that has been doped into the fiber. Dyes which have been examined include derivatives of rhodamine and pyromethene. SIF deduced loss results in combination with cutback loss measurements on undoped fibers suggest that the electronic absorption of the laser dye dominates the loss far (> 200 nm) from the peak of the dye absorption (the order of 0.5 cm-1 at 750 nm). Loss measurements of unclad undoped fibers suggest that loss is dominated by scattering and defect mechanisms. In fact these losses are quite high compared to literature measurements of analogous clad fibers. Thus intrinsic loss of the polymer (PMMA in most cases) is minor compared to scattering and defect losses when dealing with unclad fibers. We also present the fit of our dye-doped fiber loss data to homogeneous and inhomogeneous broadening equations and show that broadening is dominated by inhomogeneous mechanisms as is expected.

Kopecky, Sarah; Dirk, Carl W.; Peralez, Albert; Rodriguez, Osvaldo; de la Rosa-Cruz, Elder; Ocampo, Miguel; Castano, Victor M.; Rodriguez, M. Rogelio

2001-06-01

295

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

296

Laser diode pumped Cr 4+:YAG passively Q-switched Nd 3+:S-FAP laser  

Microsoft Academic Search

A laser diode pumped Cr4+:YAG repetitively and passively Q-switched Nd3+:S-FAP laser is studied theoretically and experimentally. The pulse energies, pulsewidths and pulse repetition rates in different conditions are measured and the experimental results are in agreement with the theoretical predictions on the whole.

Xingyu Zhang; Shengzhi Zhao; Qingpu Wang; Lianke Sun; Shaojun Zhang; Guangtao Yao; Zhenya Zhang

1998-01-01

297

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

298

Excitation of Hermite Gaussian modes in end-pumped solid-state lasers via off-axis pumping  

Microsoft Academic Search

We demonstrate a method for the excitation of Hermite Gaussian modes (one transverse dimension) in end-pumped solid-state lasers. The excitation is performed by pumping off-axis with the help of a fibre-coupled laser diode. With increasing transverse separation of the fibre from the optical axis, the Hermite Gaussian modes can be successively observed. This laser has a variable M2-factor and can

H. Laabs; B. Ozygus

1996-01-01

299

University of Florida nuclear pumped laser program. [excitation of laser gaseous  

NASA Technical Reports Server (NTRS)

The mechanism of excitation of laser gases by fast ions (triton, proton, or fission fragments) and especially any role UF6 might play in radiative deexcitation of these gases were investigated. Population densities of excited important for laser action were obtained. Nuclear pumped CW-laser systems, especially He-Ne and CO2, were studied using steady state reactors. It was demonstrated that He-Ne lases in a CW-mode with nuclear pumping at both the red and the infrared transition. The infrared transition was observed to be superradiant.

Schneider, R. T.

1979-01-01

300

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

301

Development of Nd,Cr co-doped laser materials for solar-pumped lasers  

NASA Astrophysics Data System (ADS)

Solar-pumped laser has attracted attention in the area of renewable energy creation. However, since the conversion efficiency from solar energy to laser energy is low, such lasers are not yet in practical use. In this work, we developed Nd3+,Cr3+ codoped YVO4 and CaYAlO4 crystals for solar-pumped laser. We succeeded to increase absorption at UV-VIS region with both crystals drastically. The absorption cross section of Nd,Cr:CaYAlO4 around 400 nm was more than 70 times that of Nd,Cr:YAG crystals. The fluorescence at 1 ?m was observed by pumping at 400 nm. It indicates that energy transfer from Cr to Nd occurred effectively.

Ogawa, Takayo; Wada, Satoshi; Higuchi, Mikio

2014-02-01

302

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

303

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

304

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

305

Optically pumped carbon dioxide laser mixtures. [using solar radiation  

NASA Technical Reports Server (NTRS)

This work explores the concept of blackbody radiation pumping of CO2 gas as a step toward utilization of solar radiation as a pumping source for laser action. To demonstrate this concept, an experiment was performed in which laser gas mixtures were exposed to 1500 K thermal radiation for brief periods of time. A gain of 2.8 x 10 to the -3rd reciprocal centimeters has been measured at 10.6 microns in a CO2-He gas mixture of 1 Torr pressure. A simple analytical model is used to describe the rate of change of energy of the vibrational modes of CO2 and to predict the gain. Agreement between the prediction and experiment is good.

Yesil, O.; Christiansen, W. H.

1979-01-01

306

Demonstration of an all-diode-pumped soft x-ray laser  

E-print Network

laser pulses with 1 J energy. Figure 1 shows a block dia- gram of the soft x-ray laser system. The pumpDemonstration of an all-diode-pumped soft x-ray laser Federico J. Furch,1,3, * Brendan A. Reagan,1); published October 27, 2009 We have demonstrated an 18.9 nm Ni-like molybdenum soft x-ray laser, pumped

Rocca, Jorge J.

307

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

308

New high performance laser dyes on the basis of quinolisinocoumarin's derivatives  

NASA Astrophysics Data System (ADS)

Discovery generation of new laser dyes on the basis of quinolisinocoumarin's derivatives in a spectral range 490-580 nm. It is exhibited, that the greatest generative efficiency and photodurability the availability for given compoundes in the third standing coumarin's basis of the strong electron acceptor, for example carbamyl-, benzimidozoli- and benzthiazolyl-groups, and in a standing seven - electron donor N-(CH2) 6 groups. Given quinolisinocoumarin's derivatives have high generative efficiency which exceeds known laser dyes in 2-3 times. Thus the photochemical stability exceeds rhodamine 6G on the order.

Anufrick, S. S.; Tarkovski, V. V.; Kuzniatsou, Y. M.; Nikitchenko, V. M.

2006-03-01

309

Highly efficient neodymium:yttrium aluminum garnet laser end pumped by a semiconductor laser array  

NASA Technical Reports Server (NTRS)

In recent experiments, 80-mW CW power in a single mode has been achieved from a neodymium:yttrium aluminum garnet (Nd:YAG) laser with only 1 W of electrical power input to a single semiconductor laser array pump. This corresponds to an overall efficiency of 8 percent, the highest reported CW efficiency for a Nd:YAG laser. A tightly focused semiconductor laser end pump configuration is used to achieve high pumping intensities (on the order of 1 kW/sq cm), which in turn causes the photon to photon conversion efficiency to approach the quantum efficiency (76 percent for Nd:YAG at 1.06 microns pumped at 0.810 micron). This is achieved despite the dual-lobed nature of the pump. Through the use of simple beam-combining schemes (e.g., polarization coupling and multireflection point pumping), output powers over 1 W and overall electrical to optical efficiencies as high as 10 percent are expected.

Sipes, D. L.

1985-01-01

310

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

311

Method and system for homogenizing diode laser pump arrays  

DOEpatents

An optical amplifier system includes a diode pump array including a plurality of semiconductor diode laser bars disposed in an array configuration and characterized by a periodic distance between adjacent semiconductor diode laser bars. The periodic distance is measured in a first direction perpendicular to each of the plurality of semiconductor diode laser bars. The diode pump array provides a pump output propagating along an optical path and characterized by a first intensity profile measured as a function of the first direction and having a variation greater than 10%. The optical amplifier system also includes a diffractive optic disposed along the optical path. The diffractive optic includes a photo-thermo-refractive glass member. The optical amplifier system further includes an amplifier slab having an input face and position along the optical path and separated from the diffractive optic by a predetermined distance. A second intensity profile measured at the input face of the amplifier slab as a function of the first direction has a variation less than 10%.

Bayramian, Andy J

2013-10-01

312

Pump power stability range of single-mode solid-state lasers with rod thermal lensing  

Microsoft Academic Search

The pump power stability range of solid-state laser resonators operating in the TEM(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

Sandro de Silvestri; Vittorio Magni; Paolo Laporta

1987-01-01

313

Cr:ZnSe laser pumped with Tm:YAP microchip laser  

NASA Astrophysics Data System (ADS)

Cr:ZnSe laser coherently longitudinally pumped with Tm:YAP microchip laser was realised. The pumping laser consisted of Tm:YAP crystal (3x3 mm) with resonator mirrors deposited directly on its faces (on rear face the dielectric layer with high reflectance for 1998 nm wavelength and high transmittance for 790 nm pumping radiation wavelength; on output face the dielectric layer with reflectance 97% at 1998 nm wavelength). The maximal output power was 5.5 W and the generated radiation wavelength was 1998 nm. The main advantage of this pumping was stable and still output without relaxation spikes (non-spiking). The Tm:YAP laser radiation was collimated and focused by the set of two CaF2 lenses. The pumping beam spot diameter inside the Cr:ZnSe crystal was 300 ?m. The Cr:ZnSe laser resonator consisted of flat rear mirror (HT at 1998 nm and HR at 2100 - 2900 nm) and curved output coupler (r = -150 mm, R = 95% at 2100 - 2700 nm). The maximal output energy of stable radiation was 4 mJ (pulse duration 10 ms, repetition rate 10 Hz). For wavelength tuning the Lyott filter (quartz plate under Brewster angle) was placed between the Cr:ZnSe crystal and output coupler. The generated radiation wavelength was continuously tunable from 2246 - 2650 nm.

Koranda, Petr; Sulc, Jan; Doroshenko, Maxim; Jelinková, Helena; Basiev, Tasoltan T.; Osiko, Vjatcheslav; Badikov, V. V.; Badikov, D.

2010-02-01

314

High energy erbium laser end-pumped by a laser diode bar array coupled to a Nonimaging Optic Concentrator  

E-print Network

, 3q w xYb phosphate glass 2 end pumped by a laser diode bar array leads to a low-cost, compact micro-laser Concentrator NOC to increase the efficiency of a w xNd:YVO laser 5 . In this paper, we present an Er:Yb:glass4High energy erbium laser end-pumped by a laser diode bar array coupled to a Nonimaging Optic

Boyer, Edmond

315

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

316

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

PubMed

We experimentally demonstrate ultrafast dynamic of generation of the 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 C(3)?(u) and B(3)?(g) states of N(2) 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. PMID:25320986

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

2014-08-11

317

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

318

Theory of nonradiative decay dynamics in intensely pumped solid-state laser media via laser photothermal diagnostics  

E-print Network

Theory of nonradiative decay dynamics in intensely pumped solid-state laser media via laser deexcitation and thermal-conduction transient evolution in solid-state laser media, resulting from intense and specifically laser media in the past 2 decades.1­3 All existing theoretical treatments of solid-state laser

Mandelis, Andreas

319

A microfluidic dye laser fabricated by nanoimprint lithography in a highly transparent and chemically resistant cyclo-olefin copolymer (COC)  

NASA Astrophysics Data System (ADS)

We present a polymer-based, microfluidic dye laser suitable for integration into polymer- or silicon-based lab-on-a-chip systems. The laser is fabricated by nanoimprint lithography (NIL) in cyclo-olefin copolymer (COC). The polymer device consists of microfluidic channels, with sizes ranging from several mm down to a few µm, and integrated optical waveguides to couple the light out of the structure, all fabricated in one single NIL step and with approximately 10 nm roughness. COC is a highly transparent, chemically resistant thermoplastic polymer optimal for the integration of microfluidic systems with optical elements. Rhodamine 6G dissolved in ethanol is used as an active medium in the laser, and the resonator is based on multiple reflections from a periodic structure of 16 µm wide, parallel microfluidic channels. Lasing from the device is observed at 577 nm, when optically pumped with a frequency doubled Nd:YAG laser emitting at 532 nm, where Rhodamine 6G has its absorption maximum.

Nilsson, Daniel; Balslev, Søren; Kristensen, Anders

2005-02-01

320

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

DOEpatents

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

Davin, J.M.

1992-09-01

321

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

DOEpatents

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

Davin, James M. (Livermore, CA)

1992-01-01

322

Frequency-doubled pulsed chemical oxygen-iodine laser as an efficient pump source for high-power solid state lasers  

Microsoft Academic Search

Output laser parameters are enhanced significantly by using laser pumping. An excellent example is usage of laser diodes for solid-state laser pumping. Although there are permanent advances towards development of this technique, its application for laser systems of more than 100 J output requires time, significant effort and expense. I propose another pumping source based on a rather simple and

P. G. Kryukov

1995-01-01

323

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.

324

High Energy Directly Pumped Ho:YLF Laser  

NASA Technical Reports Server (NTRS)

The most commonly used crystal architecture to produce 2 micrometer laser is co-doping Ho and Tm into a single host crystal. In this method, the stored energy transfer from the Tm (3)F4 to the Ho (5)I7 manifold is not fast enough to warrant high efficiency for short pulse applications. By separating the Ho and the Tm ions and doping the Tm in YALO3 and the Ho in YLF, we were able to directly pump the Ho (5)I7 manifold with 1.94 micrometers. The Ho:YLF laser has produced 33 mJ at 2.062 micrometers with a quantum efficiency of 0.88. The performance of each laser will be presented.

Petros, Mulugeta; Yu, Ji-Rong; Singh, Upendra N.; Barnes, Norman P.

2000-01-01

325

Spatial coherence of a single-frequency ring Nd : YAG chip laser with diode pumping  

SciTech Connect

The spatial coherence of the radiation emitted by a single-frequency ring Nd : YAG chip laser with a diode pumping was determined. The maximum value of the degrees coherence was 0.99994{+-}0.00003. The factors limiting the spatial coherence of the radiation of low-power diode-pumped solid-state lasers was discussed. (control of laser radiation parameters)

Kravtsov, Nikolai V; Firsov, V V [D.V. Skobel'tsyn Institute of Nuclear Physics, M.V. Lomonosov Moscow State University, Moscow (Russian Federation); Laptev, G D [International Laser Center, M. V. Lomonosov Moscow State University, Moscow (Russian Federation); Morozov, E Yu [Department of Physics, M.V. Lomonosov Moscow State University, Moscow (Russian Federation)

1998-01-31

326

Spectroscopy and efficient laser action from diode pumping of a new broadly  

E-print Network

Spectroscopy and efficient laser action from diode pumping of a new broadly tunable crystal: Yb3 November 12, 2001 The first demonstration of laser action in a Yb3 :Sr3Y(BO3)3 crystal is reported) and hence is of particular interest for diode-pumped femtosecond and tunable laser sources. Efficient

Boyer, Edmond

327

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

328

Photophysical parameters and laser activity of 3(4-dimethylamino-phenyl)-1-(2, 5-dimethyl-thiophen-3-yl)-propenone (DDTP): A new potential laser dye  

NASA Astrophysics Data System (ADS)

The photophysical parameters such as singlet absorption, molar absorptivity, oscillator strength, dipole moment, fluorescence spectra and fluorescence quantum yield of DDTP were measured in different solvents. DDTP dye exhibits red shift in both absorption and emission spectra as solvent polarity increases, indicating that the dipole moment of DDTP dye is higher in excited state than that in the ground state. The density functional calculation were used to obtain the ground state and excited state dipole moments for it has proven to be suitable for calculating electronic excitation energy. A crystalline solid of DDTP gives excimer like emission at 575 nm. The absorption and emission spectra of DDTP have been investigated in organized media of aqueous micellar solution. The critical micelle concentration (CMC) of sodium dodecyl sulphate (SDS), cetyltrimethyl ammonium bromide (CTAB) and triton X-100 (TX-100) are determined using DDTP dye. Dye solution ca 1×10-3 mol dm-3 in dimethyl sulfoxide (DMSO) gives laser emission in the range 490-560 nm with emission maximum at 520 nm upon pumping by nitrogen laser (337.1). The gain coefficient (?) and emission cross section ?e at maximum laser emission are also determined.

El-Daly, Samy A.; Asiri, Abdullah M.; Obeid, Abdullah Y.; Khan, Salman A.; Alamry, Khalid A.; Hussien, Mahmoud A.; Al-Sehemi, Abdullah G.

2013-02-01

329

Lamp-excited dye laser with diffraction divergence  

Microsoft Academic Search

Based on experience with partial compensation of phase distortions of the wavefront, owing to optical nonuniformities of solid state and gaseous active media [3] with the help of retroreflector optics [4], it may be expected that retroreflector mirrors (RRM) can also be used effectively in cavities with liquid active media, in particular, with dye solutions. The purpose of this work

B. A. Barikhin; K. P. Barkovskii; V. B. Gerasimov; A. L. Dudarevich; E. V. Kudryavkin; V. E. Naruta; V. I. Nedolugov; V. K. Orlov; A. G. Petukhov; V. I. Ral'chenko; A. I. Chernomordin

1986-01-01

330

Rigrod laser-pumped-laser resonator model: II. Application to thin and optically-dilute laser media  

NASA Astrophysics Data System (ADS)

In part I of this paper, and to set the foundation for this part II, we derived the resonator equations describing the normalized intensities, output power, gain, and extraction efficiency for a standard resonator incorporating two dielectric mirrors and a gain element. We then generalized the results to include an absorbing region representing a second laser crystal characterized by a small-signal transmission T0. Explicit expressions were found for the output power extracted into absorption by the second laser crystal and the extraction efficiency, and the limits to each were discussed. It was shown that efficient absorption by a thin or dilute second laser crystal can be realized in resonators in which the mirror reflectivities were high and in which the single-pass absorption was low, due to the finite photon lifetime and multi-passing of the absorbing laser element. In this paper, we apply the model derived in part I to thin or dilute laser materials, concentrating on a Yb, Er:glass intracavity pumped by a 946 nm Nd:YAG laser, a Yb, Er:glass laser-pumped intracavity by a 977 nm diode laser, and an Er:YAG laser-pumped intracavity to a 1530 nm diode laser. It is shown that efficient absorption can be obtained in all cases examined.

Brown, D. C.

2014-08-01

331

CW submillimeter wave laser pumped by an RF-excited CO2 waveguide laser  

NASA Astrophysics Data System (ADS)

Optical pumping of a submillimeter wave (SMMW) laser with a relatively compact continuous wave CO2 waveguide laser is reported. The CO2 laser beam is directed into the SMMW cavity through a 1.5-mm hole in the mirror of the SMMW laser, which is an unoptimized hole-coupled resonator with a 90-cm long metal waveguide. Part of the beam is reflected off the Brewster angle ZnSe window, a portion of which is reflected into a stable infrared Fabry-Perot interferometer, used as a frequency stabilization element. Another portion of the beam from the Brewster angle window can be combined with the output of a stable CO2 laser and fed into a HgCdTe photomixer for frequency determination. Increased frequency tunability of the waveguide pump laser was demonstrated and it has resulted in new low threshold SMMW emissions by pumping into absorption lines which are beyond the tuning range of a conventional CO2 laser.

Tobin, M. S.

1981-02-01

332

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

333

Behavior of threshold pump power of diode end-pumped solid-state lasers in critical cavity configurations  

NASA Astrophysics Data System (ADS)

The influence of transverse mode locking in critical cavity configurations on the threshold pump power of diode end-pumped solid-state lasers was investigated both theoretically and experimentally for the large portion of the cavity stability region. An experimental study was performed for lasers based on Nd:YLF, Nd:YVO4, Nd:GdVO4 and Nd:KGW crystals.

Bezotosnyi, V. V.; Cheshev, E. A.; Gorbunkov, M. V.; Koromyslov, A. L.; Kostryukov, P. V.; Krivonos, M. S.; Popov, Yu M.; Tunkin, V. G.

2015-02-01

334

Modeling of longitudinally pumped solid-state lasers exhibiting reabsorption losses  

Microsoft Academic Search

Many solid-state lasers of current exhibit reabsorption loss. Previous modeling calculations of laser performance with longitudinal pumping either have neglected reabsorption loss or have been valid only for certain special cases of the ratio of the pump- and laser-beam waists. Rigorous numerical modeling calculations have been carried out to provide a comprehensive understanding of the behavior of longitudinally pumped solid-state

W. P. Risk

1988-01-01

335

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

336

The theoretical analysis of the THz of the CO2 laser pumped CH3OH  

NASA Astrophysics Data System (ADS)

This paper established a model of three-energy-level system from the laser rate equation theory, and then analyzed the molecular dynamic processes and laser mechanism of the optically pumped CH3OH. According to the experimental parameters, the CO2 laser is used to pump CH3OH to emit pulsed THz laser lines. When the 9P(36) line of CO2 laser pumps CH3OH, the 118.8 ?m line radiation is obtained, and then we analyze the three-energy-level system's the number of particles and the characteristics of the output waveform, and the influence of the pump light, buffer gas pressure and output coupler reflectivity on laser output power. The results show that this model reveals the generate terahertz optical pump laser process correctly.

Lan, Hui; Wang, Xingbing

2014-07-01

337

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

338

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

PubMed

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

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

2014-03-10

339

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

340

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

341

Laser Scanning Confocal Microscopy Study of Dye Diffusion in Fibers Ye Song, Mohan Srinivasarao,*, Alan Tonelli, C. M. Balik, and Ralph McGregor  

E-print Network

to noninvasively obtain high-resolution three-dimensional images of the spatial distribution of dyes (fluorescein, and the ability not only to determine the total dye content of the fiber but also to image the dye distributionLaser Scanning Confocal Microscopy Study of Dye Diffusion in Fibers Ye Song, Mohan Srinivasarao

Srinivasarao, Mohan

342

Runaway electron beam control for longitudinally pumped metal vapor lasers  

NASA Astrophysics Data System (ADS)

Physics and techniques for producing of the pulsed runaway electron beams are considered. The main obstacle for increasing electron energies in the beams is revealed to be a self- breakdown of the e-gun's gas-filled diode. Two methods to suppress the self-breakdown and enhance the volumetric discharge producing the e-beam are offered and examined. Each of them provides 1.5 fold increase of the ceiling potential on the gun. The methods also give the ways to control several guns simultaneously. Resulting in the possibility of realizing the powerful longitudinal pumping of metal-vapor lasers on self-terminated transitions of atoms or ions.

Kolbychev, G. V.; Kolbycheva, P. D.

1995-08-01

343

Fabrication of pump combiners for high-power fiber lasers  

NASA Astrophysics Data System (ADS)

A custom fabrication procedure for pump combiners matched to a wide variety of double-clad fibers used in high power fiber lasers has been developed. Both combiners with and without feedthrough can be fabricated with an improved repeatability thanks to a specific mechanical setup that simplifies placing the fibers in their proper location within the input bundle before the tapering and fusion processes. Extensive characterization results on 7-to-1 and on (6+1)-to-1 combiners are confirming the validity of the proposed approach.

Braglia, Andrea; Olivero, Massimo; Neri, Alessandra; Perrone, Guido

2011-02-01

344

Thermal damage control of dye-assisted laser tissue welding: effect of dye concentration  

NASA Astrophysics Data System (ADS)

Successful laser-assisted tissue welding was implemented to provide proper weld strength with minimized tissue thermal injury. We investigated and compared the weld strengths and morphologic changes in porcine small intestinal submucose (SIS) and porcine ureteral tissues with various concentration of indocyanine green (ICG) and with a solid albumin sheet. The study showed that the tissues were welded at lower ICG concentration (0.05 mM) with minimized tissue thermal damage using an 800-nm wavelength diode laser.

Xie, Hua; Buckley, Lisa A.; Prahl, Scott A.; Shaffer, Brian S.; Gregory, Kenton W.

2001-05-01

345

Simple and high performance DFB laser based on dye-doped nanocomposite volume gratings  

NASA Astrophysics Data System (ADS)

This letter reports on the optimized design and operation performance of a second order distributed feedback (DFB) dye laser based on an active organic waveguide with a volume Bragg grating. The DFB gratings were inscribed holographically in a dye-doped organic nanocomposite containing high refractive index inorganic nanoparticles. In this work we experimentally investigated and theoretically analyzed the influence of waveguide and grating parameters on the spectral and energy characteristics of this kind of DFB laser in order to obtain a narrow-band emission of low divergence. We will show that a tailored improvement of the waveguide and grating parameters provides a low-threshold laser emission in the spectral range of 570–620?nm with a linewidth of less than 0.05?nm and an output beam profile close to a Gaussian distribution.

Smirnova, Tatiana N.; Sakhno, Oksana V.; Fitio, Volodymyr M.; Gritsai, Yuri; Stumpe, Joachim

2014-12-01

346

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

347

Delivering pump light to a laser gain element while maintaining access to the laser beam  

DOEpatents

A lens duct is used for pump delivery and the laser beam is accessed through an additional component called the intermediate beam extractor which can be implemented as part of the gain element, part of the lens duct or a separate component entirely.

Beach, Raymond J. (Livermore, CA); Honea, Eric C. (Sunol, CA); Payne, Stephen A. (Castro Valley, CA)

2001-01-01

348

New highly efficient laser bars and laser arrays for 8xx-10xx nm pumping applications  

NASA Astrophysics Data System (ADS)

High-power laser bars and laser arrays are attractive light sources for many industrial applications such as direct material processing or as pump sources for solid state and fiber lasers. There is also a great interest in quasi-CW laser bars for laser ignition and fusion applications. These applications require a continuous improvement of laser diodes for reliable operation at high output powers densities and simultaneously high electrical-to-optical efficiencies. JENOPTIK presents an overview of recent progress in the development of highly efficient CW and quasi-CW laser devices emitting in a wide wavelength range between 880 nm and 1020 nm. Laser arrays emitting in the wavelength range 915 nm to 976 nm exhibit very high efficiencies above 65%. Our technology of new generation 940 nm high fill-factor bars has been currently extended to emission wavelength of 1020 nm with excellent results: 200 W output power with 63% efficiency using passively cooled heatsinks. Additionally, performances of high brightness low fill-factor laser bars with resonator lengths of 4 mm are shown. The innovative design of the laser structure enables, moreover, the realization of 500 W - 880 nm quasi-CW laser bars with wall-plug efficiencies of 55% and a narrow fast-axis divergence angle of 40° (95% power content).

Pietrzak, A.; Huelsewede, R.; Zorn, M.; Hirsekorn, O.; Sebastian, J.; Meusel, J.; Bluemel, V.; Hennig, P.

2014-03-01

349

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

350

Tm-Doped Fibre Laser Pumped Cr2+:ZnSe Poly-Crystal Laser  

NASA Astrophysics Data System (ADS)

Demonstrations of cw lasing in Cr2+:ZnSe poly-crystal are reported. The laser consists of a 1.7-mm-thick Cr2+:ZnSe poly-crystal disc pumped by a Tm-silica double-clad fibre laser at 2050nm. Using a concave high-reflection mirror with a radius of curvature of 500mm as the rear mirror, the laser delivers up to 1030mW of radiation around 2.367 ?m.

Yang, Yong; Tang, Yu-Long; Xu, Jian-Qiu; Hang, Yin

2008-01-01

351

Laser Diode-Pumped Organic Semiconductor Lasers Utilizing Two-Dimensional Photonic Crystal Resonators  

Microsoft Academic Search

Two-dimensional photonic crystal lasers based on the small molecule organic semiconductor tris-(8-hydroxyquinoline) aluminum (Alq 3) doped with 4-Dicyanomethylene-2-methyl-6-(p-dimethylaminostyryl)-4H-pyran (DCM) are optically pumped with a conventional low-cost pulsed (In)GaN laser diode. We compare photonic crystal resonators providing first- and second-order distributed feedback and find threshold values of 1.9 and 3.2kW\\/cm2, respectively. Such inorganic-organic hybrid laser systems open up a way to

Christian Karnutsch; Marc Stroisch; Martin Punke; Uli Lemmer; Jing Wang; Thomas Weimann

2007-01-01

352

LD side-pumped Nd:YAG Q-switched laser without water cooling  

Microsoft Academic Search

A novel LD side-pumped Nd:YAG Q-switched solid-state laser, which made use of the special pumping strcture with conductive cooling instead of water cooling, was investigated.After selecting an appropriate length and diameter of Nd:YAG laser crystal rod and using three groups of laser diode centimeter bar which was composed by 12 laser diodes and uniformly arranged according to the angle of

Ming Ling; Guang-Yong Jin; Xue-Chun Tan; Zhi-Chao Wu; Zhu Liang

2009-01-01

353

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

354

Scaling laser-diode pumped solid-state amplifiers to the petawatt level  

Microsoft Academic Search

Summary form only given. Increased performance of high-power laser-diodes, decline in laser-diode-power cost, development of new lasing materials, progress on key optical components, and novel pulse-compression techniques enable the design of efficient petawatt-class amplifiers based on diode-pumped chirped-pulse amplification technology. New research in high-field plasma physics, laser-pumped X-ray sources, laser fusion, particle accelerators and generators, as well as astro-physics is

T. Topfer; J. Hein; G. Quednau; M. Hellwing; J. Philipps; H.-G. Walther; W. Theobald; R. Sauerbrey; W. Wintzer; D. Ehrt; K. Stollberg; D. Wolff; D. Habs; M. D. Perry

2001-01-01

355

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

356

Diamond cooling of high power diode pumped solid state lasers  

NASA Astrophysics Data System (ADS)

We have demonstrated the feasibility of cooling high power solid-stae lasers with diamond windows, whose thermal conductivity is about two orders of magnitude higher than sapphire's. An output power of 200Watt was achieved froma single Nd:YVO4 slab in a zigzag configuration when pumped with 600Watt diodes at 808nm. The maximum output power reported in the literature with conventional cooling schemes is about 50W. A 2.3x4x24mm3 slab was pumped from its broad side (4x24 mm2) through a 0.3mm thick optical diamond window placed in close contact with the lasing crystal. The diamond window, held in a water-cooled copper housing acted as a heat conductor. The other broad side of the crystal was cooled directly by its water-cooled copper housing. Since pumping and cooling were along the same axis, a Cartesian thermal gradient was achieved, while the zigzag scheme was used to minimize thermal lensing. By using a BBO Q-switch, 70Watt average power was obtained at 20kHz with a pulse width of 19msec and with a beam quality of 3 and 12 times diffraction limit in the zigzag and transverse directions respectively. The output of a two-head configuration was 295Watt.

Tzuk, Yitshak; Tal, Alon; Goldring, Sharone; Glick, Yaakov; Lebiush, Eyal; Kaufman, Guy; Lavi, Raphael

2003-06-01

357

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

358

An actively mode-locked Ho: YAG solid laser pumped by a Tm: YLF laser  

NASA Astrophysics Data System (ADS)

A continuous wave mode-locked (CWML) Ho: YAG laser based on an acousto-optic modulator (AOM) pumped by a 1.9??m Tm: YLF laser is demonstrated. This is the first time a report on an active CWML Ho: YAG laser has been published. A maximum output power of 1.04?W at 2097.25?nm in the CWML regime is obtained at a pump power of 13.2?W, corresponding to a slope efficiency of 13.3%. The mode-locked pulse repetition frequency is 82.76?MHz and the single pulse energy is 12.57?nJ. The mode-locked pulse width is 102?ps measured through a no-background second harmonic autocorrelation with KTP as the nonlinear crystal. Furthermore, the M2 factor is calculated to be 1.146.

Yao, B. Q.; Cui, Z.; Wang, J.; Duan, X. M.; Dai, T. Y.; Du, Y. Q.; Yuan, J. H.; Liu, W.

2015-02-01

359

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

360

Diode-pumped, cryogenically cooled, femtosecond burst mode laser  

NASA Astrophysics Data System (ADS)

We present a novel approach for the construction of a high energy, high power burst mode laser system, based on diode pumped cryogenically cooled Yb:CaF2. The system consists of a frontend producing pulses of 300 fs duration with 1 MHz. Bursts of 1000 subsequent pulses are cut from the continuous train by an electro optical modulator. Afterwards the duration of the individual pulses is stretched to 50 ps. The amplifier system consists of two amplifiers. Both amplifiers utilize mirror based relay imaging schemes to allow for a sufficient number of extraction passes for achieving efficient energy extraction. The goal parameters of the system are to achieve a total energy of 5J per burst with a repetition rate of 10Hz. Amplification results for the first of two amplifiers are demonstrated. A total output energy of 480 mJ was achieved corresponding to an optical to optical efficiency from absorbed pump energy to extracted energy of more than 17%. Single pulse energies of up to 7.5mJ are generated when changing to less pulses per burst. To achieve a constant energy from pulse to pulse during the burst we present a technique based on the modulation of the laser diode current during one pulse. With this technique the gain variation during the burst was than 5% peak to peak.

Körner, Jörg; Hein, Joachim; Liebetrau, Hartmut; Kahle, Martin; Seifert, Reinhard; Klöpfel, Diethard; Kaluza, Malte C.

2013-05-01

361

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

362

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

SciTech Connect

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

Nag, A.; Chakrabarty, T.; Bhattacharyya, K. (Indian Association for the cultivation of Science, Calcutta (India))

1990-05-17

363

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

SciTech Connect

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

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

1996-01-01

364

Calmodulin activation of the Ca2+ pump revealed by fluorescent chelator dyes in human red blood cell ghosts  

PubMed Central

Ca2+ transport in red blood cell ghosts was monitored with fura2 or quin2 incorporated as the free acid during resealing. This is the first report of active transport monitored by the fluorescent intensity of the chelator dyes fura2 (5-50 microM) or quin2 (250 microM) in hemoglobin-depleted ghosts. Since there are no intracellular compartments in ghosts and the intracellular concentrations of all assay chelator substances including calmodulin (CaM), the dyes, and ATP could be set, the intracellular concentrations of free and total Ca [( Cafree]i and [Catotal]i) could be calculated during the transport. Ghosts prepared with or without CaM rapidly extruded Ca2+ to a steady- state concentration of 60-100 nM. A 10(4)-fold gradient for Ca2+ was routinely produced in medium containing 1 mM Ca2+. During active Ca2+ extrusion, d[Cafree]i/dt was a second order function of [Cafree]i and was independent of the dye concentration, whereas d[Catotal]i/dt increased as a first order function of both the [Cafree]i and the concentration of the Ca:dye complex. CaM (5 microM) increased d[Catotal]i/dt by 400% at 1 microM [Cafree]i, while d[Cafree]i/dt increased by only 25%. From a series of experiments we conclude that chelated forms of Ca2+ serve as substrates for the pump under permissive control of the [Cafree]i, and this dual effect may explain cooperativity. Free Ca2+ is extruded, and probably also Ca2+ bound to CaM or other chelators, while CaM and the chelators are retained in the cell. PMID:1371307

1992-01-01

365

High-power CW diode-laser-array-pumped solid-state lasers and efficient nonlinear optical frequency  

NASA Astrophysics Data System (ADS)

During the interim period of this bridging contract, we have continued to work on the development of high-power cw diode-laser-array-pumped solid-state lasers. Towards that end, we have built lower power lasers in order to test individual components needed for the high-power laser, specifically we have built a 1 watt ring laser and a 5 watt slab laser. The 1 watt laser was used to study the injection locking process while assembling all the necessary electronics. We have demonstrated that it is possible to injection lock a diode-pumped laser using a single piezo-mounted mirror due to the lower intrinsic laser noise compared to an arc-lamp-pumped system. This allows us to optimize the injection locking servo loop and build a more stable locking system. The 5 watt laser was used as a test bed to find a practical way to mount the slab laser while minimizing the losses that occur at the total internal reflection (TIR) points in the slab. After trying many different means of protecting the TIR surfaces, we found that a new product from DuPont, Teflon AF 1600, has all the properties needed to provide a low loss protective coating. Using this material, the laser had a cavity loss of below 2%, which allowed for efficient operation of the laser in a side-pumped design. This laser produced 5 watts of output power with a slope efficiency near 20%.

Shine, Robert J.; Byer, Robert L.

1994-01-01

366

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

367

High-performace cladding-pumped erbium-doped fibre laser and amplifier  

SciTech Connect

We report cladding-pumped erbium-doped fibre laser and amplifier configurations. Through fibre design optimisation, we have achieved a record-high laser slope efficiency, 40 % with respect to absorbed pump power ({lambda} = 976 nm), and an output power of 7.5 W. The erbium-doped fibre amplifier efficiency reaches 32 %.

Kotov, L V; Likhachev, M E; Bubnov, M M; Medvedkov, O I; Lipatov, D S; Vechkanov, N N; Guryanov, Aleksei N

2012-05-31

368

Aligning microcavity resonances in silicon photonic-crystal slabs using laser-pumped thermal tuning  

E-print Network

, for example, can be tailored to give all-pass,1 bandpass,2 flat-top,2 or channel-drop3 filter responseAligning microcavity resonances in silicon photonic-crystal slabs using laser-pumped thermal tuning in silicon photonic-crystal PhC slabs using laser-pumped thermal tuning. The thermal gradient resulting from

Fan, Shanhui

369

Highly efficient optically pumped vertical-emitting semiconductor laser with more than  

E-print Network

an optically pumped vertical-external-cavity surface-emitting laser (OP-VECSEL) generating more than 20 W of cw to as the vertical- external-cavity surface-emitting laser (VECSEL), substantially increased the TEM00 output power to currently 0.5 W [1]. The concept of optically pumped VECSELs (OP-VECSELs) [2,3] further re- duces

Keller, Ursula

370

Experimental observation of longitudinal-mode selection in nonuniformly pumped injection lasers  

SciTech Connect

An experimental Al/sub x/Ga/sub 1-x/As-GaAs mode-selection effect for DH lasers using nonuniform pumping has been observed. The output spectrum has also been measured for injector lasers operating with pulsed pump currents.(AIP)

Borodulin, V.I.; Konyaev, V.P.; Novikova, E.R.; Tager, A.A.; Tregub, D.P.; Utkina, O.A.; Elenkrig, B.B.

1983-07-01

371

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

372

FM mode-locked, laser-diode-pumped La(1-x)Nd(x)MgAl11O19 laser  

Microsoft Academic Search

This paper presents the operating characteristics of a FM laser diode pumped La(1-x)Nd(x)MgAl11O19 (LNA) laser mode-locked by an electrooptic phase modulator. Transform limited pulses as short as 14 ps at an average output power of 50 mW are obtained when pumped by a 500-mW broad-stripe laser diode.

D. W. Hughes; A. Majdabadi; J. R. M. Barr; D. C. Hanna

1993-01-01

373

Ultraviolet ultrafast pump--probe laser based on a Ti:sapphire laser system  

SciTech Connect

An ultrafast spectroscopic pump--probe apparatus for detection of ultraviolet time-resolved spectra is described. Frequency doubling of an 810-nm 0.3-TW Ti:sapphire laser system yields 15-mJ 165-fs pulses at 405 nm. We obtain pulse energies of 0.8 mJ by frequency tripling to 270 nm. An ultraviolet supercontinuum extending from 200 to 600 nm is also generated in water by use of the frequency-doubled 405-nm light. The system operates at a 5-Hz repetition rate and is useful for applications in deep-ultraviolet pump--probe subpicosecond spectroscopy.

Rodriguez, G.; Roberts, J.P.; Taylor, A.J. (Group CST-5, MS E543, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States))

1994-08-01

374

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

375

Development of Nd,Cr co-doped laser materials for solar-pumped lasers  

NASA Astrophysics Data System (ADS)

Solar-pumped lasers have attracted attention in the area of renewable energy creation. However, since the conversion efficiency from solar energy to laser energy is low, such lasers are not yet in practical use. In this work, we grew and evaluated Nd3+,Cr3+-co-doped YVO4 and CaYAlO4 crystals for solar-pumped lasers. We succeeded in dramatically increasing the absorption from the ultraviolet to visible region using both crystals. The maximum absorption coefficient was 58 cm-1 at 402 nm for 1.0 at. % Cr-co-doped Nd:YVO4 crystal. The absorption coefficient of Nd,Cr:CaYAlO4 reached 52 cm-1 at 430 nm in the case of 0.1 at. % Cr doping. Strong fluorescence at 1 µm was observed upon pumping Nd,Cr:YVO4 at 400 nm. The result indicates effective energy transfer from Cr to Nd occurred in the Nd,Cr:YVO4.

Ogawa, Takayo; Wada, Satoshi; Higuchi, Mikio

2014-08-01

376

High-power diode-pumped cryogenically-cooled Yb:CaF2 laser with extremely low quantum defect  

E-print Network

the most promising laser materials for high-energy/high-power diode-pumped laser systems [13High-power diode-pumped cryogenically-cooled Yb:CaF2 laser with extremely low quantum defect S-peak power laser with high repetition rate, very interesting laser development at cryogenic temperature has

Boyer, Edmond

377

Scalable concept for diode-pumped high-power solid-state lasers  

Microsoft Academic Search

A new, scalable concept for diode-pumped high-power solid-state lasers is presented. The basic idea of our approach is a very thin laser crystal disc with one face mounted on a heat sink. This allows very high pump power densities without high temperature rises within the crystal. Together with a flat-top pump-beam profile this geometry leads to an almost homogeneous and

A. Giesen; H. Hügel; A. Voss; K. Wittig; U. Brauch; H. Opower

1994-01-01

378

Ti : sapphire laser pumped by the second harmonic of a pulsed diode-pumped Nd : YAG laser for two-photon spectroscopy  

SciTech Connect

The characteristics of a ring Ti : sapphire laser with gain modulation and frequency tuning using a prism beamsplitter are presented. The output pulse duration was about 50 ns at a pulse repetition rate of 7 - 18 kHz, and the frequency tuning range was 30 nm. The radiation bandwidth of the laser with a 0.7-mm-thick intracavity Fabry - Perot etalon was 12 GHz. The maximum average output power reached 160 mW at the pump power of 4.5 W and the pulse repetition rate of 7 kHz. As a pump laser, we used a diode-pumped frequency-doubled Q-switched Nd :YAG laser. (lasers)

Donin, Valerii I; Yakovin, Dmitrii V; Gribanov, A V [Institute of Automation and Electrometry, Siberian Branch, Russian Academy of Sciences, Novosibirsk (Russian Federation)

2009-03-31

379

Single-shot spectral measurements and mode correlations in a multimode pulsed dye laser  

SciTech Connect

Statistical cross correlations between mode intensities in individual pulses from a multimode dye laser have been studied by using a Fizeau interferometer and a high-resolution linear photodiode array. We find that positive intensity cross correlations develop between modes separated by certain characteristic frequencies. This appears to be a result of spatial hole burning in the standing-wave cavity. The gain competition between certain modes is minimized because of the spatial inhomogeneity of the mode intensity distributions in the gain medium.

Westling, .A.; Raymer, M.G.; Snyder, J.J.

1984-04-01

380

Two-wavelength dye-laser operation using a reflecting Fizeau interferometer  

Microsoft Academic Search

Newly found reflection properties of the Fizeau wedge interferometer are shown to be of particular advantage in obtaining\\u000a efficient multi-wavelength operation of dye lasers. Use is made of the fact that the reflecting Fizeau wedge can ensure at\\u000a once a selective feedback for a given wavelength and quasi-total reflection in an other direction for all other wavelengths.\\u000a Fully independent tuning

M. N. Nenchev; Y. H. Meyer

1981-01-01

381

Light harvesting and energy transfer in laser-dye-labeled poly(aryl ether) dendrimers  

Microsoft Academic Search

The photophysical properties of a series of laser-dye-labeled poly(aryl ether) dendrimers, generations 1--4, have been determined. The dendrimers act as extremely efficient light-harvesting antennae capable of transferring light energy through space from their periphery to their core. The light-harvesting ability of these molecules increases with generation due to an increase in the number of peripheral chromophores. The energy-transfer efficiency was

Alex Adronov; Sylvain L. Gilat; J. M. J. Frechet; Kaoru Ohta; Frederik V. R. Neuwahl; Graham R. Fleming

2000-01-01

382

Short-laser-pulse-induced photoelectric phenomena and reorientation in nematics activated with ionic dyes  

Microsoft Academic Search

The photoelectric phenomena and orientational nonlinearity induced by nanosecond laser pulses in planar layers of liquid crystals\\u000a oriented by silicon oxide (SiO) and activated with polymethine dyes were investigated. These phenomena are due to the photogeneration\\u000a of surface and bulk charges in the liquid crystal cell, their spatial distribution between the grating vector and the beam\\u000a propagation directions, and the

S. V. Serak; A. A. Kovalev; A. V. Agashkov

2000-01-01

383

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

NASA Technical Reports Server (NTRS)

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

Lin, C.; Dienes, A.

1973-01-01

384

Reducing Thermal Effect in End-Diode-Pumped Laser Crystal by Using a Novel Resonator  

NASA Astrophysics Data System (ADS)

We report a new way, i.e. double-end-pumping, to extend the stability range of a laser resonator, in advantage of making the thermal loading be effectively divided between the ends of the laser crystal to reduce the thermal effect, thus to extend the stability range. Using this new way, we experimentally obtained a 2.7-W cw laser source at 671 nm by intracavity frequency doubling of 1342 nm of a Nd:YVO4 laser based on the nonlinear crystal LiB3O5. The maximum pump power is 28 W, which is higher than 13 W of the single-end-pumping.

Yao, Ai-Yun; Hou, Wei; Li, Hui-Qing; Bi, Yong; Lin, Xue-Chun; Geng, Ai-Cong; Kong, Yu-Peng; Cui, Da-Fu; Xu, Zu-Yan

2005-03-01

385

Design criteria for mode size optimization in diode-pumped solid-state lasers  

Microsoft Academic Search

Based on space-dependent rate equation analysis, design and optimization criteria for the mode size of diode-pumped solid-state lasers are proposed, assuming an TEM00 single transverse mode in the resonator and circular or elliptic Gaussian pump beam. The optimum ratio between mode and pump spot size increases with input power and ellipticity of the pump beam. Simple plots may be used

Paolo Laporta; Marcello Brussard

1991-01-01

386

Optimization of a Raman shifted dye laser system for DIAL applications  

NASA Technical Reports Server (NTRS)

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

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

1990-01-01

387

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

388

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

NASA Technical Reports Server (NTRS)

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

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

1992-01-01

389

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

390

Electrically pumped hybrid AlGaInAs-silicon evanescent laser  

Microsoft Academic Search

An electrically pumped light source on silicon is a key element needed for photonic integrated circuits on silicon. Here we report an electrically pumped AlGaInAs-silicon evanescent laser architecture where the laser cavity is defined solely by the silicon waveguide and needs no critical alignment to the III-V active material during fabrication via wafer bonding. This laser runs continuous-wave (c.w.) with

Alexander W. Fang; Oded Cohen; Richard Jones; Mario J. Paniccia; John E. Bowers

2006-01-01

391

A solar-pumped CW 18 W Nd:YAG laser  

Microsoft Academic Search

The development of a solar-pumped Nd:YAG laser is reported. A solar energy collector consisting of a paraboloidal mirror 10 m in aperture and 3.2 m in focal length is used to pump a water-cooled Nd:YAG laser rod 4 mm in diameter and 75 mm in length. The maximum output of the laser is 18 W in multi-mode, the highest output

Haruo Arashi; Yasuo Oka; Nenokichi Sasahara; Atsushi Kaimai; Mareo Ishigame

1984-01-01

392

Preliminary results with sutured colonic anastomoses reinforced with dye-enhanced fibrinogen and a diode laser  

NASA Astrophysics Data System (ADS)

A common cause of morbidity in patients recovering from bowel surgery is leakage from colonic anastomoses. A technique utilizing a laser activated protein solder to strengthen colonic anastomoses in a canine model was evaluated. Following creation of six single-layer interrupted suture anastomoses in four dogs, a protein solder consisting of indocyanine green dye and fibrinogen was topically appied to the serosal surface and exposed to 808 nm continuous wave diode laser energy. Immediately following anastomosis, the mean leakage pressure of sutures alone was 129 +/- 14 mm hg (n equals 6), while the mean leakage pressure of sutures reinforced with the laser welded solder was 312 +/- 32 mm hg (n equals 6) (p <0.001). Histologic examination of sections take through the anastomosis demonstrated a layer of fibrinogen across the anastomotic gap without evidence of thermal injury. Laser activated protein solder significantly enhances the immediate strength of sutured colonic anastomoses without causing appreciable thermal injury to surrounding tissues.

Libutti, Steven K.; Williams, Matthew R.; Oz, Mehmet C.; Forde, Kenneth A.; Bass, Lawrence S.; Weinstein, Samuel; Auteri, Joseph S.; Treat, Michael R.; Nowygrod, Roman

1991-07-01

393

Fast photocatalytic degradation of methylene blue dye using a low-power diode laser.  

PubMed

This study focused on the application of diode lasers as alternative light sources for the fast photocatalytic degradation of methylene blue. The photocatalytic decomposition of methylene blue in aqueous solution under 443nm laser light irradiation was found to be technically feasible using Ag/AgCl nanoparticles as photocatalysts. The effects of various experimental parameters, such as irradiation time, light source, catalyst loading, initial dye concentration, pH, and laser energy on decolorization and degradation were investigated. The mineralization of methylene blue was confirmed by chemical oxygen demand analysis. The results demonstrate that the laser-induced photocatalytic process can effectively degrade methylene blue under the optimum conditions (pH 9.63, 4mg/L MB concentration, and 1.4g/L Ag/AgCl nanoparticles). PMID:25285998

Liu, Xianhua; Yang, Yulou; Shi, Xiaoxuan; Li, Kexun

2015-02-11

394

Design of an advanced diode-pumped solid state laser for high-altitude airborne operations  

NASA Astrophysics Data System (ADS)

As part of the Advanced Targeting FLIR (ATFLIR) program for the United States Navy, Raytheon has designed and developed a compact and rugged diode-pumped solid-state laser for high-altitude airborne targeting systems. This laser is based on the relatively mature Nd:YAG technology. In the laser pump head, 168 diode bars are stacked into 24 arrays, which, in turn, are packed around the laser rod to provide 4-sided optical pumping. These standard 20°C operating temperature diode bars and the laser rod are conductively cooled to fins located in the air flow circulating in the pod housing. The laser operates with very low variation in output energy or beam divergence at laser pulse rates from 8 to 20 Hertz and ambient temperatures from -54 to +71°C. The optical to optical efficiency of the pump head is better than 25%. Eye safe laser wavelengths are achieved thorough the use of an Optical Parametric Oscillator. This compact and rugged diode-pumped solid-state laser with proven performance and reliability on high altitude aircrafts can also be modified to serve as transmitters for a variety of airborne laser remote sensing applications. It also has the potential to serve as laser transmitters for spaceborne applications with some design changes and space qualifications.

Nieuwsma, Daniel E.; Wang, Jinxue

2005-01-01

395

A three-level model for alkali metal vapor lasers. Part II: broadband optical pumping  

NASA Astrophysics Data System (ADS)

The effects of pump laser spectral bandwidth on the performance of longitudinally pumped diode-pumped alkali lasers is explored by extending the analytic, three-level model using longitudinally averaged number densities. By assuming a statistical distribution between the upper two levels, the limiting solution for the quasi-two level system is achieved. A second limiting solution is identified for strongly bleached conditions where the atom recycle rate, limited by spin-orbit relaxation, fully specifies the output power. Performance in the intermediate regime depends significantly on the pump bandwidth relative to the atomic absorption line width and requires numerical simulation. The ratio of populations for the two excited, 2P3/2,1/2 states completes an analytic solution and depends primarily on pump laser bandwidth, threshold, and alkali concentration. Absorption well into the wings on the atomic profile can be utilized by increasing alkali concentration, but imposes increased pump intensity threshold.

Hager, Gordon D.; Perram, Glen P.

2013-09-01

396

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.

397

Diode-pumped doubly resonant all-intracavity continuous-wave ultraviolet laser at 336 nm  

NASA Astrophysics Data System (ADS)

We report for the first time a coherent ultraviolet radiation at 336 nm by intracavity sum-frequency generation of a 912 nm Nd:GdVO4 laser and a 532 nm frequency doubling Nd:YVO4 laser. The ultraviolet laser is obtained by using a doubly resonator, type-I critical phase matching CsLiB6O10 (CLBO) crystal sum-frequency mixing. With a total diode pump power of 31.8 W (13.1 W pump power for 912 nm Nd:GdVO4 laser and 18.7 W pump power for 532 nm Nd:YVO4 frequency doubling laser), TEM00 mode ultraviolet laser at 336 nm of 93 mW is obtained. The power stability is better than 3.4% and laser beam quality M2 factors are 1.52 and 1.27 in both horizontal and vertical dimensions respectively.

Lü, Y. F.; Sun, G. C.; Fu, X. H.; Liu, Z. T.; Chen, J. F.

2010-08-01

398

Power density in direct nuclear-pumped He-3 lasers  

NASA Technical Reports Server (NTRS)

The interaction of neutron beams with He-3 gas is of interest for nuclear pumped lasers. The effects of spectral dependence of the neutron beam, neutron attenuation in the gas-filled laser tube, and transport of the charged-particle He-3(n, p)He-3 reaction products are treated in detail. An expression for the energy density as a function of position within the tube, tube radius, operating pressure, and neutron fluence is given. The maximum energy density within the optical cavity is achieved when the tube radius is 3.26/P where P (atm) is the operating pressure. The variation of radius by 50% above and below optimum will change the energy density at most by 10%, although performance degrades quickly for radii outside this range. If the optimum tube radius is used for each operating pressure, then the power density on the centerline (kW/cu cm) is given as 9.3 x 10 to the -18th power times the operating pressure times flux in a thermal neutron environment of flux (n/sq cm sec).

Wilson, J. W.; Deyoung, R. J.

1978-01-01

399

Feasibility study: Monodisperse polymer particles containing laser-excitable dyes  

NASA Technical Reports Server (NTRS)

The optical properties associated with small particles, which include aerosols, hydrosols and solid microspheres have an impact on several areas of science and engineering. Since the advent of high-speed computers and lasers, the interaction of light with matter in the form of small particles with a discontinuous optical boundary relative to the surroundings has been much better understood. Various nonlinear optical effects have been observed involving interaction of a laser beam with both solid microspheres and liquid microdroplets. These include observation of second and third harmonic generation, four wave mixing, optical visibility, two photon absorption, observation of stimulated emission and lasing, and Stimulated Raman Scattering. Many of these effects are observed with laser intensities which are orders of magnitude less than that required by threshold condition for interactions in macroscopic bulk medium. The primary reason for this is twofold. The front surface of the microsphere acts as a thick lens to enhance the internal intensity of the input laser radiation, and the spherical shape of the droplet acts as an optical cavity to provide feedback at specific wavelengths corresponding to the whispering gallery modes or the morphology dependent resonances (MDR's). The most interesting and significant recent finding in this field is undoubtedly the existence of resonance peaks in linear and nonlinear optical spectra. Such resonance peaks are only dependent on the particle morphology, which means the size, shape and refractive index of the particle. Because of the simultaneous presence of these resonances, they have been referred to by many names, including structural resonances, whispering modes or whispering gallery modes, creeping waves, circumferential waves, surfaces modes, and virtual modes. All of these names refer to the same phenomena, i.e. morphology dependent resonances (MDR's) which has already been described and predicted precisely by electromagnetic theory and Loentz-Mie theory since 1908. MDR's can become important when the particle size (radius a) approaches and exceeds the wavelength of the electromagnetic wave (lambda) and the refractive index of the particle is greater than that of the surrounding medium. Such resonances are easiest to observe from a single particle with high symmetry, such as a sphere, spheroid, or cylinder. MDR's correspond to solutions of the characteristic equations of the electromagnetic fields in the presence of a sphere.

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

1993-01-01

400

Diode-pumped tunable Tm : YLF laser for mid-infrared gas spectroscopy  

SciTech Connect

The spectral characteristics of the longitudinally diode-pumped Tm : YLF laser radiation are experimentally studied. The laser wavelength was tuned within a spectral range of 1860 - 1940 nm with a linewidth not exceeding 1 nm. The effect of water vapour on the spectral characteristics is studied. (lasers)

Eremeikin, O N [Institute of Applied Physics, Russian Academy of Sciences, Moscow (Russian Federation); Savikin, A P; Pavlenko, K Yu; Sharkov, V V [N. I. Lobachevski State University of Nizhni Novgorod, Nizhnii Novgorod (Russian Federation)

2010-08-27

401

High power 2 {micro}m wing-pumped Tm{sup 3+}:YAG laser  

SciTech Connect

Using a scalable diode end-pumping technology developed at Lawrence Livermore National Laboratory the authors have demonstrated a compact Tm{sup 3+}:YAG laser capable of generating greater than 50 W of cw 2 {micro}m laser output power. The design and operational characteristics of this laser will be discussed.

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

1996-01-01

402

Diode-pumped solid state laser phototherapy for treatment of neonatal hyperbilirubinemia  

NASA Astrophysics Data System (ADS)

The authors introduce the design of a diode-pumped solid- state laser phototherapy unit, capable of fulfilling the recommendations of the clinical use of laser in phototherapy for the treatment of neonatal hyperbilirubinemia. This compact laser power unit has the advantages of easy application by the medical staff plus being more cost effective.

Hamza, Mostafa; El-Ahl, Mohammad H. S.; Hamza, Ahmad M.

2001-01-01

403

Pump radiation distribution in multi-element first cladding laser fibres  

SciTech Connect

Pump radiation transfer is studied experimentally in multi-element first cladding laser fibres. A model of this process is proposed, which is in good agreement with experimental results. An all-fibre single-mode cw ytterbium laser based on a three-element first cladding fibre with an output power of 100W is fabricated. (lasers)

Mel'kumov, Mikhail A; Bufetov, Igor' A; Bubnov, M M; Shubin, Aleksei V; Semenov, S L; Dianov, Evgenii M [Fiber Optics Research Center, Russian Academy of Sciences, Moscow (Russian Federation)

2005-11-30

404

Comparative study of diode-pumped hydrocarbon free Rb and K vapor lasers  

NASA Astrophysics Data System (ADS)

Based on the kinetic model of diode-pumped alkali vapor lasers, operation parameters including helium pressure, temperature and output mirror reflectivity are optimized for hydrocarbon free Rb laser and K laser. A comparative study on the output characteristics of hydrocarbon free Rb laser and K laser is also carried out. Results show that a better capability is presented in hydrocarbon free K laser instead of hydrocarbon free Rb laser, such as lower pump threshold, higher laser gain and optical-to-optical efficiency. The performance difference between K and Rb laser is mainly induced by the difference of helium pressure, which results in an evident difference on the absorption cross section and emission cross section.

Gao, Fei; Chen, Fei; Xie, Jijiang; Li, Dianjun; Xie, Jingjiang; Yang, Guilong; Zheng, Changbin; Xu, Yan; Guo, Jin

2014-06-01

405

Tunable laser operation of a Tm 3+-doped tellurite glass laser near 2 ?m pumped by a 1211 nm semiconductor disk laser  

NASA Astrophysics Data System (ADS)

We report on the performance around 1970 nm of a thulium-doped TZNG bulk glass laser pumped by a semiconductor disk laser (SDL) emitting at 1211 nm. A pump-limited maximum output power of 60 mW at 1946 nm was obtained with a measured slope efficiency of 22.4%. The tuning range of 115 nm extended from 1850 nm to 2040 nm. Comparison with a previously reported performance when pumped at 793 nm with Ti:sapphire laser is discussed highlighting the competitiveness of pumping at 1211 nm.

Fusari, F.; Vetter, S.; Lagatsky, A. A.; Richards, B.; Calvez, S.; Jha, A.; Dawson, M. D.; Sibbett, W.; Brown, C. T. A.

2010-07-01

406

Microfluidic laser embedded in glass by three-dimensional femtosecond laser microprocessing  

Microsoft Academic Search

Microfluidic dye lasers three-dimensionally embedded in glass have been fabricated for what is believed to be the first time by integrating micro-optical and microfluidic components by use of a femtosecond laser. By pumping the microfluidic laser, in which the microfluidic chamber was filled with the laser dye Rhodamine 6G dissolved in ethanol, with a frequency-doubled Nd:yttrium aluminum garnet laser, lasing

Ya Cheng; Koji Sugioka; Katsumi Midorikawa

2004-01-01

407

Kinetic study of laser-induced photocatalytic degradation of dye (alizarin yellow) from wastewater using nanostructured ZnO  

Microsoft Academic Search

Nanoparticles of zinc oxide semiconductor were applied for removal of toxic organic pollutants such as dyes (alizarin yellow GG) from wastewater using laser induced photocatalytic process. A special photoreactor was designed for this purpose using local resources. Laser enhanced photo degradation of alizarin yellow GG (AYGG) was carried out by irradiating the contaminated aqueous solution with a 355 nm radiation

Khizar Hayat; Mohammed A. Gondal; Mazen M. Khaled; Shakeel Ahmed

2010-01-01

408

DYE LASER SOURCE OF MONOCHROMATIC UV-B AND UV-C RADIATIONS FOR BIOLOGICAL ACTION SPECTROSCOPY  

EPA Science Inventory

The authors have used a flashlamp driven tunable dye laser as a radiation source for observing UV-C and UV-B action spectra of two eukaryotic microorganisms. The general nature of the irradiation system and various operating parameters are described. The laser produces the high p...

409

Study of a low power dissipation, miniature laser-pumped rubidium frequency standard  

NASA Astrophysics Data System (ADS)

This paper studies a miniature low power consumption laser-pumped atom vapour cell clock scheme. Pumping 87Rb with a vertical cavity surface emitting laser diode pump and locking the laser frequency on a Doppler-broadened spectral line, it records a 5 × 10-11?-1/2 (? < 500 s) frequency stability with a table-top system in a primary experiment. The study reveals that the evaluated scheme is at the level of 2.7 watts power consumption, 90 cm3 volume and 10-12?-1/2 short-term frequency stability.

Liu, Guo-Bin; Zhao, Feng; Gu, Si-Hong

2009-09-01

410

Compact soft x-ray laser pumped by a pulse-train laser  

SciTech Connect

Recent experimental results of Al XI x-ray lasing in recombining plasmas are described. ASE{close_quote}s of two Li-like Al lines (105.7 A and 154.7 A) were observed using a pulse-train laser with only 2.3 J/cm pumping energy. Gain coefficient of 105.7 A was improved up to over 4 cm{sup {minus}1} when laser intensity of the second half of a pulse-train laser was reduced to 25{percent} of the first one. The time duration of the gain was about 1 ns. Also a experiment on double-pass amplification of Al{sup 10+} 154.7 A line was carried out by using an x-ray multi-layer mirror and increase of the line intensity by a factor of 4.4 was observed. {copyright} {ital 1996 American Institute of Physics.}

Hara, T.; Ando, K.; Aoyama, M.; Aoyagi, Y. [The Institute of Physical and Chemical Research, Wako-shi, Saitama 351-01 (Japan)

1996-05-01

411

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. Deguil, F. Salin, "High power diode-pumped Yb:KGW ultrafast laser," in OSA Trends in Optics and Photonics (TOPS) Vol. 73, Conference on Lasers and Electro-Optics, OSA Technical Digest (Optical Society

Major, Arkady

412

Low-threshold sub-10 fs mode-locked Ti:sapphire laser pumped by 488 nm fiber laser  

NASA Astrophysics Data System (ADS)

We demonstrated the first low-threshold mode-locked Ti:sapphire oscillator pumped by a 488 nm fiber laser. Laser pulses as short as 8.2 fs with a bandwidth wider than 400 nm at a repetition rate of 148 MHz were generated under a pump power as low as 504 mW. Using a 0.5% output coupler, we further realized a 280 mW threshold power for mode-locking operation.

Yu, Zijiao; Han, Hainian; Zhang, Long; Teng, Hao; Wang, Zhaohua; Wei, Zhiyi

2014-10-01

413

Resonance enhancement of optoacoustic signal for frequency stabilization of CO2 laser pump for CH3OH FIR laser  

Microsoft Academic Search

The resonance enhancement of an optoacoustic signal, generated in methyl alcohol vapor, is investigated with the objective of obtaining a reliable discriminator at reduced pump power levels. The 9P(36) pump line from a CO2 laser is used throughout the study. The optoacoustic signal strength and resonator Q are measured at the fundamental longitudinal resonant frequency for various resonator geometries and

J. R. Fishback; M. Azar; C. A. Ventrice; D. P. Hutchinson

1988-01-01

414

Diffractive Combiner of Single-Mode Pump Laser-Diode Beams  

NASA Technical Reports Server (NTRS)

An optical beam combiner now under development would make it possible to use the outputs of multiple single-mode laser diodes to pump a neodymium: yttrium aluminum garnet (Nd:YAG) nonplanar ring oscillator (NPRO) laser while ensuring that the laser operates at only a single desired frequency. Heretofore, an Nd:YAG NPRO like the present one has been pumped by a single multimode laser-diode beam delivered via an optical fiber. It would be desirable to use multiple pump laser diodes to increase reliability beyond that obtainable from a single pump laser diode. However, as explained below, simplistically coupling multiple multimode laser-diode beams through a fiber-optic combiner would entail a significant reduction in coupling efficiency, and lasing would occur at one or more other frequencies in addition to the single desired frequency. Figure 1 schematically illustrates the principle of operation of a laser-diode-pumped Nd:YAG NPRO. The laser beam path is confined in a Nd:YAG crystal by means of total internal reflections on the three back facets and a partial-reflection coating on the front facet. The wavelength of the pump beam - 808 nm - is the wavelength most strongly absorbed by the Nd:YAG crystal. The crystal can lase at a wavelength of either 1,064 nm or 1,319 nm - which one depending on the optical coating on the front facet. A thermal lens effect induced by the pump beam enables stable lasing in the lowest-order transverse electromagnetic mode (the TEM00 mode). The frequency of this laser is very stable because of the mechanical stability of the laser crystal and the unidirectional nature of the lasing. The unidirectionality is a result of the combined effects of (1) a Faraday rotation induced by an externally applied magnetic field and (2) polarization associated with non-normal incidence and reflection on the front facet.

Liu, Duncan; Wilson, Daniel; Qiu, Yueming; Forouhar, Siamak

2007-01-01

415

Method for optical pumping of thin laser media at high average power  

DOEpatents

A thin, planar laser material is bonded to a light guide of an index-matched material forming a composite disk. Diode array or other pump light is introduced into the composite disk through the edges of the disk. Pump light trapped within the composite disk depletes as it multi-passes the laser medium before reaching an opposing edge of the disk. The resulting compound optical structure efficiently delivers concentrated pump light and to a laser medium of minimum thickness. The external face of the laser medium is used for cooling. A high performance cooler attached to the external face of the laser medium rejects heat. Laser beam extraction is parallel to the heat flux to minimize optical distortions.

Zapata, Luis E. (Livermore, CA); Beach, Raymond J. (Livermore, CA); Honea, Eric C. (Sunol, CA); Payne, Stephen A. (Castro Valley, CA)

2004-07-13

416

Direct nuclear-pumped lasers using the He-3/n,p/H-3 reaction  

NASA Technical Reports Server (NTRS)

A description is presented of experimental results concerning a specific class of direct nuclear-pumped lasers classified as 'volumetric nuclear lasers'. In the considered laser system a fissioning gas, He-3, is mixed with the lasing gas to form a homogeneous mixture, resulting in uniform volume excitation. In typical volumetric nuclear lasers a fast-burst reactor is used as a source of neutrons which penetrate a polyethylene moderator. Here the fast neutrons are thermalized. After thermalization, neutrons scatter into the laser cell. Nuclear reactions produce a proton of 0.56 MeV and a tritium ion of 0.19. These ions produce secondary electrons which pump the laser medium creating a population inversion. The results reported demonstrate direct nuclear pumping of He-3-Ar, Xe, Kr, and Cl with the considered system.

Deyoung, R. J.; Jalufka, N. W.; Hohl, F.

1978-01-01

417

Requirements for a laser pumped FEL operating in the X-ray regime  

NASA Astrophysics Data System (ADS)

A laser pumped free electron laser (FEL) can in principle generate coherent, polarized, high power X-rays using a much lower energy electron beam than would be required by a conventional FEL. This is due to the dramatic reduction in the wiggler period, which in the case of a laser pumped FEL is the laser wavelength. However, a number of practical obstacles could prevent the realization of a laser pumped FEL in the laboratory. Foremost amongst these is the requirement that the axial velocity spread on the electron beam be less than the difference between the average velocity of the beam and the velocity of the ponderomotive wave. This requirement places a severe limitation on both the beam emittance and energy spread. Conditions are given on the emittance, energy spread, current density, and laser intensity needed to achieve lasing in the X-ray regime.

Gordon, D. F.; Sprangle, P.; Hafizi, B.; Roberson, C. W.

2001-12-01

418

Histological study on the treatment of vascular malformations resistant to pulsed dye laser  

PubMed Central

Background and Aims: The pulsed dye laser (PDL) is recognized both as an effective treatment for vascular malformations and the as first treatment of choice for these lesions. However, PDL irradiation has poor efficacy in some patients, particularly the elderly. The present study histologically assessed such patients to try to elucidate the reason. Materials and Methods: A pulsed dye laser was used in 3 subjects in whom previous laser treatment was ineffective. Three-millimeter punch biopsies were obtained before laser treatment, 1 week and 3 months after the laser treatment. Each specimen was stained with toluidine blue and examined under light microscopy followed by electron microscopy with oolong tea extract (OTE) staining. Results: Microscopy revealed an increase in the vasculature at baseline and an increased number of dermal fibroblasts. One week post-irradiation, inflammatory cell infiltration was observed together with extensive interstitial perivascular edema. At 1 week and 3 months after laser irradiation, normal structures were observed for both blood vessels and capillary endothelial cells. Mild changes were noted in other interstitial features, but findings obtained 3 months after irradiation were almost similar to those before irradiation. Conclusions: The lower efficacy of PDL treatment in the elderly was possibly due to the markedly low amount of red blood cells in our subjects' blood vessels, a major chromophore for the PDL, was markedly low. It is possible that age-related denaturation of dermal matrix collagen plays some role in maintaining the vasculature in the interstitium with edema, and inflammatory cell infiltration could lead to the cellular release of some cytokines which favor reconstruction of the vasculature. PMID:24204091

Seiji, Kawana; Sato, Shigeru; Naito, Zenya

2013-01-01

419

40 W cw TEM00 mode diode-laser-pumped Nd:YAG zigzag miniature-slab laser  

NASA Astrophysics Data System (ADS)

We have built a cw, diode-laser-pumped, Nd;YAG slab laser that emits 72 W of multimode power when pumped with 235 W, or 40 W of TEM00 power when pumped with 212 W of diode laser power. The slope efficiencies are 36% for multimode operation and 22% for TEM00 mode operation. The laser uses the zig-zag slab geometry to reduce the thermal effects associated with high power operation, resulting in less than one wave of distortion at the full pump power. Reasonable efficiency for the side- pumped slab design was obtained by confining the pump power within a gold-coated box which surrounds the slab. TEM00 mode operation was obtained in a simple three-mirror folded cavity. The Nd:YAG slab acted as an aperture in the cavity and the astigmatism due to off axis incidence on a curved mirror corrected for a minor 1 meter cylindrical thermal lens. A significant advantage of our design over previous slab lasers is a new Teflon AF protective coating on the slab total internal reflection surfaces which greatly simplifies the mounting and cooling of the slab laser medium.

Shine, Robert J., Jr.; Alfrey, Anthony J.; Byer, Robert L.

1995-04-01

420

One-megawatt solar pumped and electrically driven lasers for space power transmission  

NASA Technical Reports Server (NTRS)

High power lasers in space could provide power for a variety of future space missions such as spacecraft electric power requirements and laser propulsion. This study investigates four electrically pumped laser systems, krypton fluoride, copper vapor, laser diode array, and the carbon dioxide laser, all scaled to 1-MW laser output. Each system obtained its primary power from a large solar photovoltaic array which, in turn, provides power for the appropriate laser power conditioning subsystem. Each system was block-diagrammed, and the power and efficiency were found for each subsystem. The laser diode array had the highest solar-to-laser efficiency (6 percent) and smallest radiator area making it the most advantageous of the electrically driven lasers studied. This system was then compared with an iodine solar pumped laser system previously studied. The diode array had a better wavelength with regard to transmission optics mass, but it also had a heavier radiator because of its lower temperature radiator requirement. A more advanced solar pumped laser could emerge as the preferred laser system for space applications.

Deyoung, R. J.; Lee, J. H.; Williams, M. D.; Schuster, G.; Conway, E. J.

1988-01-01

421

40-W cw, TEM00-mode, diode-laser-pumped, Nd:YAG miniature-slab laser  

NASA Astrophysics Data System (ADS)

We have built a diode-laser-pumped Nd:YAG slab laser that emits 40 W of cw power in a TEM00 mode and 72 W of power in multimode operation when pumped with 235 W. The slope efficiencies are 22% for TEM00-mode operation and 36% for multimode operation. The laser uses a zigzag slab geometry to reduce thermally induced distortions and operates at less than one wave of distortion at the full pump power. A significant advantage of our design over those of previous slab lasers is a new Teflon AF protective coating on the slab total-internal-reflection surfaces, which greatly simplifies the mounting and cooling of the slab laser medium.

Shine, R. J., Jr.; Alfrey, A. J.; Byer, R. L.

1995-03-01

422

40-W cw, TEM(00)-mode, diode-laser-pumped, Nd:YAG miniature-slab laser.  

PubMed

We have built a diode-laser-pumped Nd:YAG slab laser that emits 40 W of cw power in a TEM(00) mode and 72 W of power in multimode operation when pumped with 235 W. The slope efficiencies are 22% for TEM(00)-mode operation and 36% for multimode operation. The laser uses a zigzag slab geometry to reduce thermally induced distortions and operates at less than one wave of distortion at the full pump power. A significant advantage of our design over those of previous slab lasers is a new Teflon AF protective coating on the slab total-internal-reflection surfaces, which greatly simplifies the mounting and cooling of the slab laser medium. PMID:19859220

Shine, R J; Alfrey, A J; Byer, R L

1995-03-01

423

University of Illinois nuclear pumped laser program. [experiments with a TRIGA pulsed reactor with a broad pulse and a low peak flux  

NASA Technical Reports Server (NTRS)

The development of nuclear pumped lasers with improved efficiency, energy storage capability, and UF6 volume pumping is reviewed. Results of nuclear pumped laser experiments using a TRIGA-type pulsed reactor are outlined.

Miley, G. H.

1979-01-01

424

Definition and analysis of the lineshape matching coefficient in diode-pumped alkali vapor lasers  

NASA Astrophysics Data System (ADS)

For diode-pumped alkali lasers (DPALs), the matching of lineshape between D2 absorption line and pump light greatly affects the properties of laser output; however, there is rare theoretical study on the quantitative description of the lineshape matching coefficient. In this paper, we put forward a formula to describe the lineshape matching coefficient that represents the matching degree between D2 absorption line and pump light. Dependences of the matching coefficient and optical-optical efficiency on the linewidth ratio between D2 absorption line and pump light, and the center frequency shift of pump light caused by mode hopping are calculated and compared with experimental results in literatures. Results show the definition of lineshape matching coefficient can provide an effective way to improve the pump efficiency of DPALs.

Shen, Binglin; Pan, Bailiang; Yang, Jing; Qian, Aiqing; Jiao, Jian

2014-12-01

425

Optimising the efficiency of pulsed diode pumped Yb:YAG laser amplifiers for ns pulse generation.  

PubMed

We present a numerical model of a pulsed, diode-pumped Yb:YAG laser amplifier for the generation of high energy ns-pulses. This model is used to explore how optical-to-optical efficiency depends on factors such as pump duration, pump spectrum, pump intensity, doping concentration, and operating temperature. We put special emphasis on finding ways to achieve high efficiency within the practical limitations imposed by real-world laser systems, such as limited pump brightness and limited damage fluence. We show that a particularly advantageous way of improving efficiency within those constraints is operation at cryogenic temperature. Based on the numerical findings we present a concept for a scalable amplifier based on an end-pumped, cryogenic, gas-cooled multi-slab architecture. PMID:22274245

Ertel, K; Banerjee, S; Mason, P D; Phillips, P J; Siebold, M; Hernandez-Gomez, C; Collier, J C

2011-12-19

426

Pulsed laser deposition of Co3O4 nanocatalysts for dye degradation and CO oxidation  

NASA Astrophysics Data System (ADS)

Co3O4 nanoparticles (NPs) assembled coatings were synthesized using pulsed laser deposition (PLD) by taking advantage of phase explosion process. The coatings were prepared at substrate temperature of 150 °C by using three different laser fluences (3, 5, and 7 J/cm2) in order to tune the size of NPs. Structural property and surface morphology of NPs were investigated by Raman spectroscopy and electron microscopy respectively. The catalytic activity of these Co3O4 NPs coatings was tested for dye degradation as well as for CO oxidation. Co3O4 coating (3 J/cm2) was able to completely degrade Methylene blue dye with significantly high rate, via photo Fenton reaction under visible light irradiation, as compared to Co3O4 powder catalyst mainly owing to the size and nanocrystalline nature of NPs on the catalyst surface. Coating synthesized at low laser fluence (3 J/cm2) showed best catalytic activity. This particular coating also showed above 90% conversion efficiency of CO to CO2 at 250 °C with very high specific rate. The special features of NPs, such as narrow size distribution, small average size (5-20 nm), perfect spherical shape, low degree of agglomeration, and nanocrystalline phase, are the main factors responsible for the enhanced catalytic activity of the PLD produced Co3O4 NPs assembled coating.

Edla, R.; Patel, N.; El Koura, Z.; Fernandes, R.; Bazzanella, N.; Miotello, A.

2014-05-01

427

Histopathology of the effects of tuneable dye laser on monkey retina  

SciTech Connect

The tuneable dye laser was used to simulate treatment of choroidal neovascularization and panretinal photocoagulation (PRP) in monkey retina. The histopathologic effects of wavelengths from 560 to 630 nm in juxtafoveal, papillomacular bundle, and nonfoveal areas were investigated. An unexpected observation using high-intensity burns in juxtafoveal and, to a lesser extent, in papillomacular bundle areas was inner retinal damage with 600-nm light. At moderate energy levels, the effect of 600 nm were more comparable with those with other wavelengths and included much less damage to the inner retinal layers. At mild energy levels, the effects were comparable with other wavelengths. During and after the application of the burns, the energy levels and ophthalmoscopic appearances were comparable for each wavelength for the high-, moderate-, and mild-intensity burns. The histopathologic effects of 630-nm light (tuneable dye red) were comparable with those of the standard krypton red (647 nm) laser. Nonmacular and PRP effects were similar with all wavelengths. These results indicate that power levels may need to be reduced when placing 600-nm (orange) laser burns in the macula.

Smiddy, W.E.; Patz, A.; Quigley, H.A.; Dunkelberger, G.R.

1988-07-01

428

High efficiency, linearly polarized, directly diode-pumped Er:YAG laser at 1617??nm.  

PubMed

An efficient, directly diode-pumped Er:YAG laser at 1617 nm was demonstrated. A folding mirror with high reflectivity for the s-polarized light at the laser wavelength was used to achieve a linearly polarized laser. A maximum continuous-wave output power of 7.73 W was yielded under incident pump power of 50.57 W, and the optical conversion efficiency with respect to incident pump power was ?15.28%, which was the highest optical conversion efficiency with directly diode-pumped Er:YAG lasers up to now; in Q-switched operation, the maximum pulse energy of 7.82 mJ was generated with pulse duration of about 80 ns at a pulse repetition frequency of 500 Hz. PMID:25607959

Yu, Zhenzhen; Wang, Mingjian; Hou, Xia; Chen, Weibiao

2014-12-01

429

Development of diode-pumped ultra-short pulse solid-state lasers.  

E-print Network

??Investigation on high performance diode-pumped solid-state (DPSS) lasers operating at various modes (continuous-wave, Q-switching, and mode-locking) is one of the most active and prosperous areas… (more)

Kong, Jian.

2008-01-01

430

Laser velocimetry study of the flow field in a centrifugal pump  

E-print Network

The flow field in the impeller passages in a centrifugal pump was measured using a two dimensional laser 2-focus velocimeter. Measurements were taken at three circumferential (azimuthal) locations at the design and off-design operating conditions...

Rashid, Kazi M.

2012-06-07

431

A high carrier injection terahertz quantum cascade laser based on indirectly pumped scheme  

E-print Network

A Terahertz quantum cascade laser with a rather high injection coupling strength based on an indirectly pumped scheme is designed and experimentally implemented. To effectively suppress leakage current, the chosen quantum ...

Razavipour, S. G.

432

The shortest wavelength far-infrared laser line from CW CO2 laser pumped CH3OH and M-independent Stark splitting of laser lines  

Microsoft Academic Search

Methyl alcohol (CH3OH) molecules pumped with the 9R(16) CW CO2 laser line generate two new far-infrared laser lines at wavelengths of 33.4 and 36.4 mu m. The 33.4 mu m line has the shortest wavelength among the sub-mm lines reported so far from CH3OH and its isotopic species pumped with CW CO2 laser lines. Stark splitting is observed on the

N. Sokabe; T. Miyatake; Y. Nishi; A. Murai

1983-01-01

433

Generation of tunable far-infrared radiation by optical pumping molecular gas lasers  

Microsoft Academic Search

This paper summarizes the results obtained by optical pumping molecular gas lasers by use of a 20 atm high-pressure CO2-laser. The far-infrared laser gases investigated were several isotopes of the methylhalides (CH3X; X ? F, Cl, Br, I), heavy water (D2O) and ammonia (NH3), that delivered around 1000 laser lines with wavelengths ranging from the millimeter region down to 40

W. Schatz

1995-01-01

434

Ultra high brightness laser diode arrays for pumping of compact solid state lasers and direct applications  

NASA Astrophysics Data System (ADS)

High Power Laser Diodes (HPLD) are increasingly used in different fields of applications such as Industry, Medicine and Defense. Our significant improvements of performances (especially in power and efficiency) and a reproducible manufacturing process have led to reliable, highly robust components. For defense and security applications these devices are used predominantly for pumping of solid state lasers (ranging, designation, countermeasures, and sensors). Due to the drastically falling price per watt they are more and more replacing flash lamps as pump sources. By collimating the laser beam even with a bar to bar pitch of only 400?m. cutting edge brightness of our stacks.is achieved Due the extremely high brightness and high power density these stacks are an enabling technology for the development of compact highly efficient portable solid state lasers for applications as telemeters and designators on small platforms such as small UAVs and handheld devices. In combination with beam homogenizing optics their compact size and high efficiency makes these devices perfectly suited as illuminators for portable active imaging systems. For gated active imaging systems a very short pulse at high PRF operation is required. For this application we have developed a diode driver board with an efficiency several times higher than that of a standard driver. As a consequence this laser source has very low power consumption and low waste heat dissipation. In combination with its compact size and the integrated beam homogenizing optics it is therefore ideally suited for use in portable gated active imaging systems. The kWatt peak power enables a range of several hundred meters. The devices described in this paper mostly operate at wavelength between 800 nm and 980nm. Results from diodes operating between 1300 nm and 1550 nm are presented as well.

Kohl, Andreas; Fillardet, Thierry; Laugustin, Arnaud; Rabot, Olivier

2012-10-01

435

Transversely diode-pumped passively Q-switched erbium glass laser emitter  

SciTech Connect

The properties of a laser diode array-pumped passively Q-switched ytterbium-erbium glass laser emitter are studied. It is found experimentally that the maximum output energy is achieved when the diameter of the TEM{sub 00} mode is 0.65-0.77 of the transverse size of the active element. By using two 100-W linear laser diode arrays with the output power not exceeding 70% of the maximum power, 5 mJ was achieved in a 50-ns diffraction-limited single pulse for the efficiency (with respect to the pump radiation energy) of 1.35%. (lasers)

Bykov, V N; Sadovoi, A G [M.F. Stel'makh Polyus Research and Development Institute, Moscow (Russian Federation); Izyneev, A A; Sadovskii, P I; Sorokina, O A [Institute of Radio Engineering and Electronics, Russian Academy of Sciences, Fryazino, Moscow Region (Russian Federation)

2008-03-31

436

Pump-probe imaging of laser-induced periodic surface structures after ultrafast irradiation of Si  

SciTech Connect

Ultrafast pump-probe microscopy has been used to investigate laser-induced periodic surface structure (LIPSS) formation on polished Si surfaces. A crater forms on the surface after irradiation by a 150 fs laser pulse, and a second, subsequent pulse forms LIPSS within the crater. Sequentially delayed images show that LIPSS with a periodicity slightly less than the fundamental laser wavelength of 780 nm appear on Si surfaces ?50 ps after arrival of the second pump laser pulse, well after the onset of melting. LIPSS are observed on the same timescale as material removal, suggesting that their formation involves material ejection.

Murphy, Ryan D. [Applied Physics Program, University of Michigan, Ann Arbor, Michigan 48109 (United States)] [Applied Physics Program, University of Michigan, Ann Arbor, Michigan 48109 (United States); Torralva, Ben [Department of Atmospheric, Oceanic and Space Sciences, University of Michigan, Ann Arbor, Michigan 48109 (United States)] [Department of Atmospheric, Oceanic and Space Sciences, University of Michigan, Ann Arbor, Michigan 48109 (United States); Adams, David P. [Sandia National Laboratories, Albuquerque, New Mexico 87123 (United States)] [Sandia National Laboratories, Albuquerque, New Mexico 87123 (United States); Yalisove, Steven M. [Department of Materials Science and Engineering, University of Michigan, Ann Arbor, Michigan 48109 (United States)] [Department of Materials Science and Engineering, University of Michigan, Ann Arbor, Michigan 48109 (United States)

2013-09-30

437

Solar-pumped 80 W laser irradiated by a Fresnel lens.  

PubMed

A solar-pumped 100 W class laser that features high efficiency and low cost owing to the use of a Fresnel lens and a chromium codoped neodymium YAG ceramic laser medium was developed. A laser output of about 80 W was achieved with combination of a 4 m(2) Fresnel lens and a pumping cavity as a secondary power concentrator. This output corresponds to 4.3% of conversion efficiency from solar power into laser, and the maximum output from a unit area of Fresnel lens was 20 W/m(2), which is 2.8 times larger than previous results with mirror-type concentrator. PMID:19148246

Ohkubo, Tomomasa; Yabe, Takashi; Yoshida, Kunio; Uchida, Shigeaki; Funatsu, Takayuki; Bagheri, Behgol; Oishi, Takehiro; Daito, Kazuya; Ishioka, Manabu; Nakayama, Yuichirou; Yasunaga, Norihito; Kido, Kouichirou; Sato, Yuji; Baasandash, Choijil; Kato, Kiyoshi; Yanagitani, Takagimi; Okamoto, Yoshiaki

2009-01-15

438

An experimental investigation of (UF-235)6 fission nuclear-pumped lasers  

NASA Technical Reports Server (NTRS)

A UF6 handling system was designed for use in conjunction with the existing nuclear-pumped laser vacuum system at a nuclear reactor laboratory to perform the experiments described above. A modification to separate the gas fill system from the vacuum system and thus greatly reduce its volume is described as well as operating procedures for the first controlled nuclear pumping experiments with UF6 vapor contained in the laser cell.

Miley, G. H.

1979-01-01

439

Broadband laser amplifier based on gas-phase dimer molecules pumped by the Sun.  

PubMed

We report the design and experimental realization of a solar-pumped dimer gas-laser amplifier. The amplifying medium is Te(2) gas, which is capable of amplifying laser signals over a broad spectral range. A gain of 42% was measured at a wavelength of 632.8 nm. We also present studies of the material characteristics and a brief review of the study of other candidate materials for solar pumping. PMID:18049599

Pe'er, I; Vishnevitsky, I; Naftali, N; Yogev, A

2001-09-01

440

A solar-pumped Nd:YAG laser in the high collection efficiency regime  

Microsoft Academic Search

Solar-pumped lasers can be used for space and terrestrial applications. We report on solar side-pumped Nd:YAG laser experiments, which included comprehensive beam quality measurements and demonstrated record collection efficiency and day long operation. A 6.75 m2 segmented primary mirror was mounted on a commercial two-axis positioner and focused the solar radiation towards a stationary non-imaging-optics secondary concentrator, which illuminated a

Mordechai Lando; Jacob Kagan; Boris Linyekin; Vadim Dobrusin

2003-01-01

441

14 J/2 Hz Yb3+:YAG diode pumped solid state laser chain.  

PubMed

The Lucia laser chain is a Diode Pumped Solid State Laser system based on Yb3+ doped YAG disks used in an active mirror scheme. Front-end and amplifier stages are presented with recent energetic performances (14 J/2 Hz) achieved with improved pumping and extraction architectures. Emphasis is given on the crucial role of ASE and thermal mitigation considerations in engineering the amplifier head. PMID:23388979

Gonçalvès-Novo, Thierry; Albach, Daniel; Vincent, Bernard; Arzakantsyan, Mikayel; Chanteloup, Jean-Christophe

2013-01-14

442

Vertical-cavity surface-emitting laser active regions for enhanced performance with optical pumping  

Microsoft Academic Search

We have developed an improved active region design for optically pumped vertical-cavity surface-emitting lasers. We have reduced device thresholds by over 50% and raised maximum lasing temperatures to 79 \\/spl deg\\/C while attaining 76% pump efficiencies.

Jon Geske; Kian-Gap Gan; Yae L. Okuno; Brandon Barnes; Joachim Piprek; John E. Bowers

2004-01-01

443

Absorption spectroscopy measurements in optically dense explosive fireballs using a modeless broadband dye laser.  

PubMed

A modeless broadband dye laser is applied to probe inside optically dense fireballs generated by high explosives using single-shot, high resolution absorption spectroscopy. Despite attenuation of the main beam by 98%, high signal-to-noise ratio absorption spectra of Al, Ti, and AlO are readily obtained at resolutions of 0.007 nm, and luminosity from the fireball is strongly rejected. Detection limits for atomic species are less than 200 ppb. The method offers good time resolution of chemistry within the fireball, and scaling laws suggest that this technique should be valid in explosives tests at least up to the gram scale. PMID:19796492

Glumac, Nick

2009-09-01

444

Single-shot spectral measurements and mode correlations in a multimode pulsed dye laser  

SciTech Connect

Statistical cross correlations between mode intensities in individual pulses from a multimode dye laser have been studied by using a Fizeau interferometer and a high-resolution linear photodiode array. It is found that positive intensity cross correlations develop between modes separated by certain characteristic frequencies. This appears to be a result of spatial hole burning in the standing-wave cavity. The gain competition between certain modes is minimized because of the spatial inhomogeneity of the mode intensity distributions in the gain medium. 17 references.

Westling, L.A.; Raymer, M.G.

1984-04-01

445

The simulation of diode side-pumped Tm:YAG laser  

NASA Astrophysics Data System (ADS)

Tm:YAG laser, the wavelength is 2.01?m which is safe for eyes, has very important application at Coherent Laser Radar and surgical medical, and is a kind of ideal laser scalpel. As its wavelength is adjacent to the water absorption peak, the laser energy can be absorbed strongly by water, thus the effect of surgical cutting and evaporation is better than traditional methods, and bring smaller surrounding tissue injury, effective vascular incision condensation. Otherwise, the laser can be carried by ordinary silica fiber. Summarily, Tm:YAG laser is quite suitable for high-precision surgery. In the high-power case, Side-pumped instrument is an efficient one. Then how to select the parameters of the structure of side-pumped laser system has important practical significance for improving the laser performance. For the development and optimization of laser system, rate equation model of quasi-three rank energy levels was used to simulating the absorption process of side-pumped optical by media, laser threshold, efficiency and optimal parameters of activation medium. The results showed that Tm: YAG laser's output energy can achieve the maximum average output power of about 110W under the given parameters. The work can be referred to practice laser performance.

Chen, Xia; Huang, Chuyun; Yao, Yucheng; Yan, Xudong; Yang, Tao; Kong, Yujie; Wang, Yanlin

2009-08-01

446

Demonstration of triple pump coherent anti-Stokes Raman scattering in a jet diffusion flame  

E-print Network

Three pulsed narrow band pump sources (a frequency doubled pulsed Nd-YAG, and two narrow band dye lasers) and a broad-band Stokes laser source are used to demonstrate triple pump coherent anti-Stokes Raman scattering in a jet diffusion flame...

Velur Natarajan, Viswanathan

2002-01-01

447

Optical pumping of helium with arc lamp excited LNA lasers C. G. Aminoff (*), C. Larat, M. Leduc and F. Lalo  

E-print Network

plasmas with polarized nuclei [13] or sources of spin polarized electrons using optically pumped helium-4827 Optical pumping of helium with arc lamp excited LNA lasers C. G. Aminoff (*), C. Larat, M at 03BB =1.083 03BCm, suitable for optical pumping in helium. The laser is made of an LNA crystal

Paris-Sud XI, Université de

448

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

NASA Astrophysics Data System (ADS)

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

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

2013-08-01

449

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

PubMed Central

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

Jain, Vikalp; Phillips, Brett T.

2013-01-01

450

Reversing the pump dependence of a laser at an exceptional point  

PubMed Central

When two resonant modes in a system with gain or loss coalesce in both their resonance position and their width, a so-called exceptional point occurs, which acts as a source of non-trivial physics in a diverse range of systems. Lasers provide a natural setting to study such non-Hermitian degeneracies, as they feature resonant modes and a gain material as their basic constituents. Here we show that exceptional points can be conveniently induced in a photonic molecule laser by a suitable variation of the applied pump. Using a pair of coupled microdisk quantum cascade lasers, we demonstrate that in the vicinity of these exceptional points the coupled laser shows a characteristic reversal of its pump dependence, including a strongly decreasing intensity of the emitted laser light for increasing pump power. PMID:24925314

Brandstetter, M.; Liertzer, M.; Deutsch, C.; Klang, P.; Schöberl, J.; Türeci, H. E.; Strasser, G.; Unterrainer, K.; Rotter, S.

2014-01-01

451

Reversing the pump dependence of a laser at an exceptional point.  

PubMed

When two resonant modes in a system with gain or loss coalesce in both their resonance position and their width, a so-called exceptional point occurs, which acts as a source of non-trivial physics in a diverse range of systems. Lasers provide a natural setting to study such non-Hermitian degeneracies, as they feature resonant modes and a gain material as their basic constituents. Here we show that exceptional points can be conveniently induced in a photonic molecule laser by a suitable variation of the applied pump. Using a pair of coupled microdisk quantum cascade lasers, we demonstrate that in the vicinity of these exceptional points the coupled laser shows a characteristic reversal of its pump dependence, including a strongly decreasing intensity of the emitted laser light for increasing pump power. PMID:24925314

Brandstetter, M; Liertzer, M; Deutsch, C; Klang, P; Schöberl, J; Türeci, H E; Strasser, G; Unterrainer, K; Rotter, S

2014-01-01

452

Diode-end-pumped 1.2 W Yb:Y?O? planar waveguide laser.  

PubMed

Fabrication, characterization and laser performance of a Watt-level ytterbium-doped yttria waveguide laser is presented. The waveguide was grown onto a YAG substrate by pulsed laser deposition and features a 6 µm thick ytterbium-doped yttria layer sandwiched between two 3 µm undoped yttria layers. The laser deposited film was characterized by X-ray diffraction, showing a high degree of crystallinity and analyzed spectroscopically, showing performance indistinguishable from previously reported bulk material. When pumped with 8.5 W from a broad area diode laser the waveguide laser produces 1.2 W of output at 1030 nm. PMID:25321579

Beecher, Stephen J; Parsonage, Tina L; Mackenzie, Jacob I; Sloyan, Katherine A; Grant-Jacob, James A; Eason, Robert W

2014-09-01

453

Generation of tunable far-infrared radiation by optical pumping molecular gas lasers  

NASA Astrophysics Data System (ADS)

This paper summarizes the results obtained by optical pumping molecular gas lasers by use of a 20 atm high-pressure CO 2-laser. The far-infrared laser gases investigated were several isotopes of the methylhalides (CH 3X; X ? F, Cl, Br, I), heavy water (D 2O) and ammonia (NH 3), that delivered around 1000 laser lines with wavelengths ranging from the millimeter region down to 40 ?m. By exploiting the continuous tunability of the CO 2-laser to pump either a waveguide laser or a multipass Raman-cell broadly tunable FIR emission can be generated via stimulated Raman scattering. Moreover the observed far-infrared laser pulses were found to have pulse durations of less than 100 ps.

Schatz, W.

1995-01-01

454

Directional Fluorescence Spectra of Laser Dye in Opal and Inverse Opal Photonic Crystals Lydia Bechger,* Peter Lodahl, and Willem L. Vos  

E-print Network

Directional Fluorescence Spectra of Laser Dye in Opal and Inverse Opal Photonic Crystals Lydia polystyrene opals and alumina inverse opals are studied, allowing us to compare direct and inverted structures emission was first reported in refs 6 and 7: titania inverse opals doped with laser dye showed a broadband

Vos, Willem L.

455

264 W output power at 1585 nm in Er-Yb codoped fiber laser using in-band pumping.  

PubMed

We demonstrate a high-power cladding-pumped Er-Yb codoped fiber laser with 74% efficiency. A pump-limited output power of 264 W is obtained using in-band pumping at 1535 nm. We compare the efficiency of 1480 and 1535 nm pumping through numerical simulations and experimental measurements. PMID:24978785

Jebali, M A; Maran, J-N; LaRochelle, S

2014-07-01

456

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

PubMed Central

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

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

1974-01-01

457

Modeling technique of capacitive discharge pumping of metal vapor lasers for electrode capacitance optimization.  

PubMed

To estimate optimum gas discharge tube (GDT) electrode capacitance of metal vapor lasers (MVLs) pumped by a longitudinal capacitive discharge, we offer to use series connection of capacitors to the electrodes of a conventionally pumped GDT with inner electrodes. It has been demonstrated that the maximum output power in CuBr lasers is obtained when the capacitances of high-voltage and ground electrodes are equal. When using a model circuit an average output power reaches 12 W that suggests the possibility of generating high average output power (>10 W) in MVLs pumped using a capacitive discharge. PMID:22667661

Gubarev, F A; Evtushenko, G S; Vuchkov, N K; Sukhanov, V B; Shiyanov, D V

2012-05-01

458

Direct diode-pumped Kerr-lens mode-locked Ti:sapphire laser  

PubMed Central

We describe a Ti:sapphire laser pumped directly with a pair of 1.2W 445nm laser diodes. With over 30mW average power at 800 nm and a measured pulsewidth of 15fs, Kerr-lens-modelocked pulses are available with dramatically decreased pump cost. We propose a simple model to explain the observed highly stable Kerr-lens modelocking in spite of the fact that both the mode-locked and continuous-wave modes are smaller than the pump mode in the crystal. PMID:22714433

Durfee, Charles G.; Storz, Tristan; Garlick, Jonathan; Hill, Steven; Squier, Jeff A.; Kirchner, Matthew; Taft, Greg; Shea, Kevin; Kapteyn, Henry; Murnane, Margaret; Backus, Sterling

2012-01-01

459

Passively mode-locked diode-pumped monolithic channel waveguide laser with a repetition rate of 4.9 GHz  

E-print Network

ranging from biophotonics to optical frequency metrology. Waveguide solid-state lasers in combination into a diode pumped monolithic configuration. The laser produced pulses with a duration of 740 fs at around 1Passively mode-locked diode-pumped monolithic channel waveguide laser with a repetition rate of 4

460

Phosphate-core silica-clad Er/Yb-doped optical fiber and cladding pumped laser.  

PubMed

We present a composite optical fiber with a Er/Yb co-doped phosphate-glass core in a silica glass cladding as well as cladding pumped laser. The fabrication process, optical properties, and lasing parameters are described. The slope efficiency under 980 nm cladding pumping reached 39% with respect to the absorbed pump power and 28% with respect to the coupled pump power. Due to high doping level of the phosphate core optimal length was several times shorter than that of silica core fibers. PMID:24718138

Egorova, O N; Semjonov, S L; Velmiskin, V V; Yatsenko, Yu P; Sverchkov, S E; Galagan, B I; Denker, B I; Dianov, E M

2014-04-01

461

Scaling CW electron beam pumped rare gas lasers to ultra-high average power  

NASA Astrophysics Data System (ADS)

The overall objective of this program is to demonstrate the feasibility of efficiently scaling Ar:Xe lasers to ultra-high average power levels for strategic defense applications. The contractor has experimentally verified that the Ar:Xe laser system, which operates at near-IR wavelengths (1.73 micrometers), can achieve laser efficiencies of 4 percent with electron beam pumping at pump power densities as low as 10 watts/cc. This new efficient electron beam pumping regime promises cost-effective scaling of Ar:Xe laser systems to multi-megawatt average power levels while maintaining high electrical efficiency (4 to 6 percent) and near-diffraction-limited beam quality. In the Phase 2 effort, detailed experiments will be performed on an electron beam pumped Ar:Xe laser with a closed cycle flow loop at pump power densities of 10 to 20 W/cc. The objective of these experiments is to validate methods for correction and control of the optical distortions resulting from experiments is to validate methods for correction and control of the optical distortions resulting from CW pumping. Control of thermal distortions will be achieved by optimally contouring the spatial profile of electron beam power deposition in the active volume. With the optimal deposition profile, higher order optical distortions will be negligible and a diffraction limited beam will be obtained after tilt and focus corrections are made. These corrections can be made by a simple local loop by an adaptive optics system in the beam train.

1991-04-01

462

High power operation of cladding pumped holmium-doped silica fibre lasers.  

PubMed

We report the highest power operation of a resonantly cladding-pumped, holmium-doped silica fibre laser. The cladding pumped all-glass fibre utilises a fluorine doped glass layer to provide low loss cladding guidance of the 1.95 µm pump radiation. The operation of both single mode and large-mode area fibre lasers was demonstrated, with up to 140 W of output power achieved. A slope efficiency of 59% versus launched pump power was demonstrated. The free running emission was measured to be 2.12-2.15 µm demonstrating the potential of this architecture to address the long wavelength operation of silica based fibre lasers with high efficiency. PMID:23481989

Hemming, Alexander; Bennetts, Shayne; Simakov, Nikita; Davidson, Alan; Haub, John; Carter, Adrian

2013-02-25

463

Low-noise Raman fiber amplifier pumped by semiconductor disk laser.  

PubMed

A 1.3 µm Raman fiber amplifier pumped by 1.22 µm semiconductor disk laser in co-propagation geometry is demonstrated. Measured relative intensity n