Characteristics of a broadband dye laser using Pyrromethene and Rhodamine dyes

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

doi:10.1364/ao.50.000901

Cited by 12 publications

(8 citation statements)

References 42 publications

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“…The moderate bandwidth mixture is Rhodamine 640 (R640) and Kiton Red 620 (KR620) dissolved in methanol, similar to that used in prior work, which provides broadband output centred near 607 nm, with a full width at half maximum (FWHM) of approximately 5-6 nm. The mixture providing broader bandwidth is a solution of Pyrromethene 597 (PM597) and Pyrromethene 650 (PM650), following the work of Tedder et al (2011). The mixture produces very broad output, covering a range of ∼570-610 nm.…”

Section: Picosecond Cars Diagnostic Systemmentioning

confidence: 99%

“…The present work, which is a follow-on to initial studies reported by Pendleton et al (2012), presents new CARS data on rotational temperature and vibrational distribution function (VDF) in nanosecond pulse discharges in nitrogen and air, both in a repetitively pulsed discharge in plane-toplane geometry and in a single-pulse discharge in point-topoint, diffuse filament geometry. By using a new broadband dye laser mixture (Tedder et al 2011), up to 20 vibrational levels could be probed, although only levels v = 0-9 were found to have populations above the detection limit. The experimental temporal evolution of rotational temperature and nitrogen VDF is compared to predictions of a coupled master equation/plasma chemistry kinetic model.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Picosecond CARS measurements of nitrogen vibrational loading and rotational/translational temperature in non-equilibrium discharges

Montello¹,

Yin²,

Burnette³

et al. 2013

J. Phys. D: Appl. Phys.

133

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Picosecond coherent anti-Stokes Raman spectroscopy (CARS) is used to study vibrational energy loading and relaxation kinetics in nitrogen and air ns pulsed non-equilibrium plasmas, in both plane-to-plane and pin-to-pin geometries. In 10 kHz repetitively pulsed plane-to-plane plasmas, up to ∼50% of coupled discharge power is found to load vibrations, in good agreement with a master equation kinetic model. In the pin-to-pin geometry, ∼40% of total discharge energy in a single pulse in air at 100 Torr is found to couple directly to nitrogen vibrations by electron impact, also in good agreement with model predictions. Post-discharge, the total quanta in vibrational levels v = 0-9 is found to increase by ∼60% in air and by a factor of ∼3 in nitrogen, respectively, a result in direct contrast to modelling results which predict the total number of quanta to be essentially constant until ultimately decaying by V-T relaxation and mass diffusion. More detailed comparison between experiment and model show that the vibrational distribution function (VDF) predicted by the model during, and directly after, the discharge pulse is in good agreement with that determined experimentally. However, for time delays exceeding ∼1 µs, the experimental VDF shows populations of vibrational levels v 2 greatly exceeding modelling results, which predict their predominant decay due to net downward V-V transfer and corresponding increase in v = 1 population. This is at variance with the experimental results, which show a significant monotonic increase in the populations of levels v = 2-9 at t ∼ 1-10 µs after the discharge pulse, both in nitrogen and air, before gradually switching to relaxation at t ∼ 10-100 µs. It is concluded that a collisional process is likely feeding high vibrational levels at a rate which is comparable to the rate at which population of the high levels is lost due to net downward V-V energy transfer. A likely candidate for the source of additional vibrational quanta is quenching of metastable electronic states of nitrogen to highly excited vibrational levels of the ground electronic state. The effect of electronic-vibrational (E-V) coupling on time-resolved N 2 vibrational populations and temperature, estimated using a phenomenological E-V energy transfer model, provides qualitative interpretation of the present experimental results.

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Section: Picosecond Cars Diagnostic Systemmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Picosecond CARS measurements of nitrogen vibrational loading and rotational/translational temperature in non-equilibrium discharges

Montello¹,

Yin²,

Burnette³

et al. 2013

J. Phys. D: Appl. Phys.

133

View full text Add to dashboard Cite

show abstract

“…Figure 4 also shows the insertion of a variable angle of incidence transmission filter between the pre-amplifier and final amplifier. When used in combination with a very broad dye mixture [18], consisting of a solution of Pyrromethene 597 and Pyrromethene 650 dyes, this enables tuning of the broadband spectral output. Figure 5 shows the spectral output, as determined from the non-resonant background (NRB) spectrum of argon, along with the Stokes wavelengths for v = 0 to v = 10 transitions of N 2 , when a 552 nm edge dichroic filter is inserted oriented at an angle of 10° with respect to the laser beam propagation axis.…”

Section: Broadband Carsmentioning

confidence: 99%

Coherent anti-Stokes Raman scattering and spontaneous Raman scattering diagnostics of nonequilibrium plasmas and flows

Lempert

Adamovich

2014

J. Phys. D: Appl. Phys.

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The paper provides an overview of the use of coherent anti-Stokes Raman scattering (CARS) and spontaneous Raman scattering for diagnostics of low-temperature nonequilibrium plasmas and nonequilibrium high-enthalpy flows. A brief review of the theoretical background of CARS, four-wave mixing and Raman scattering, as well as a discussion of experimental techniques and data reduction, are included. The experimental results reviewed include measurements of vibrational level populations, rotational/translational temperature, electric fields in a quasi-steady-state and transient molecular plasmas and afterglow, in nonequilibrium expansion flows, and behind strong shock waves. Insight into the kinetics of vibrational energy transfer, energy thermalization mechanisms and dynamics of the pulse discharge development, provided by these experiments, is discussed. Availability of short pulse duration, high peak power lasers, as well as broadband dye lasers, makes possible the use of these diagnostics at relatively low pressures, potentially with a sub-nanosecond time resolution, as well as obtaining single laser shot, high signal-to-noise spectra at higher pressures. Possibilities for the development of single-shot 2D CARS imaging and spectroscopy, using picosecond and femtosecond lasers, as well as novel phase matching and detection techniques, are discussed. 45 I 2

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“…The moderate bandwidth mixture is Rhodamine 640 (R640) and Kiton Red 620 (KR620) dissolved in methanol, similar to that used in prior work, which provides broadband output centered near 607 nm, with a full width at half maximum (FWHM) of approximately 5-6 nm. The mixture providing broader bandwidth is a solution of Pyrromethene 597 (PM597) and Pyrromethene 650 (PM650), following the work of Tedder et al (2011). The mixture produces very broad output, with a range covering from ~570-610 nm.…”

Section: B Picosecond Cars Diagnostic Systemmentioning

confidence: 99%

“…By using a new broadband dye laser mixture (Tedder 2011), up to 20 vibrational levels could be probed, although only levels v=0-9 were found to have populations above the detection limit. The experimental temporal evolution of rotational temperature and nitrogen VDF is compared to predictions of a coupled master equation / plasma chemistry kinetic model.…”

Section: Introductionmentioning

confidence: 99%

Picosecond CARS Measurements of Nitrogen Vibrational Loading and Rotational/Translational Temperature in Nonequilibrium Discharges

Montello

Yin

Burnette

et al. 2012

43rd AIAA Plasmadynamics and Lasers Conference

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Picosecond Coherent Anti-Stokes Raman Spectroscopy is used to study vibrational energy loading and relaxation kinetics in nitrogen and air nsec pulsed non-equilibrium plasmas, in both plane-to-plane and pin-to-pin geometries. In 10 kHz repetitively pulsed plane-to-plane plasmas, up to ~50% of coupled discharge power is found to load vibrations, in good agreement with a master equation kinetic model. In the pin-to-pin geometry, ~33% of total discharge energy in a single pulse in air at 100 torr is found to couple directly to nitrogen vibrations by electron impact, also in good agreement with model predictions. Post-discharge, the total quanta in vibrational levels v=0-9 is found to increase by a factor of ~2 in air and by a factor of ~4 in nitrogen, respectively, a result in direct contrast to modeling results which predict the total number of quanta to be essentially constant until ultimately decaying by V-T relaxation and mass diffusion. More detailed comparison between experiment and model show that the vibrational distribution function (VDF) predicted by the model during, and directly after, the discharge pulse is in good agreement with that determined experimentally. However, for time delays exceeding ~10 μsec, the experimental VDF shows populations of vibrational levels v≥2 greatly exceeding modeling predictions, which predicts their monotonic decay due to net downward V-V transfer and corresponding increase in v=1 population. This is at variance with the experimental results, which show an increase in the populations of levels v=2 and v=3, reaching a maximum at t~50-100 μsec after the discharge pulse, and relatively steady v=4-9 populations at t~10-100 μsec. It is concluded that a collisional process is feeding high vibrational levels at a rate which is comparable to the rate at which population of the high levels is lost due to net downward V-V energy transfer. A likely candidate for the source of additional vibrational quanta is quenching of metastable electronic states of nitrogen to highly excited vibrational levels of the ground electronic state.

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Characteristics of a broadband dye laser using Pyrromethene and Rhodamine dyes

Cited by 12 publications

References 42 publications

Picosecond CARS measurements of nitrogen vibrational loading and rotational/translational temperature in non-equilibrium discharges

Picosecond CARS measurements of nitrogen vibrational loading and rotational/translational temperature in non-equilibrium discharges

Coherent anti-Stokes Raman scattering and spontaneous Raman scattering diagnostics of nonequilibrium plasmas and flows

Picosecond CARS Measurements of Nitrogen Vibrational Loading and Rotational/Translational Temperature in Nonequilibrium Discharges

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