Femtosecond two-photon laser-induced fluorescence of krypton for high-speed flow imaging

Wang, Yejun; Capps, C. David; Kulatilaka, Waruna D.

doi:10.1364/ol.42.000711

Cited by 21 publications

(9 citation statements)

References 14 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It is important to point out that these lines fall within the transmission linewidth of commonly used bandpass filters for the Kr 5p' [3/2] 2 -5s' [1/2] 1 transition, and may constitute a source of error when interpreting PMT data, if not taken into consideration. Interestingly, the presence of additional fluorescence features has also been observed in femtosecond-TALIF related research [25,26]. An evaluation of the filtered emission spectra with their respective transmission curves shows very good agreement for the bandpass filter used for Kr but only fair agreement for that of N. Fortuitously, the effective transmission -given by the product of the respective normalized linestrengths with either the experimental or datasheet valuesonly differ by around 1%, and no further attempt is made to understand this discrepancy.…”

Section: Fluorescence Spectramentioning

confidence: 64%

TALIF measurements of atomic nitrogen in the afterglow of a nanosecond capillary discharge

Chng

Lepikhin

Orel

et al. 2020

Plasma Sources Sci. Technol.

View full text Add to dashboard Cite

The atomic nitrogen (N) density in a nanosecond pulse capillary discharge is measured using two-photon laser induced fluorescence (TALIF). The capillary discharge is favored for its unique combination of both large reduced fields (E/N) and high specific deposited energies. Under such conditions, we find that a pure nitrogen (N2) capillary discharge at a pressure of 27 mbar and temperature of about 300 K, produces a peak N-atom density of 1.29 • 10 17 cm -3 , corresponding to an extremely high dissociation degree of about 10%. The time evolution of the N-atom density is tracked from a few hundred ns after discharge initiation, up to several ms when the concentration of N-atoms falls below the detection limit. The temporal evolution curve exhibits a trapezoidal-like shape, characterized by an initial rise in the N-atom density up to a few µs, followed by a relatively flat and constant profile until about 1 ms, and finally terminating with a drop to near detection limits at about 10 ms. The high electron densities (≈10 15 cm -3 ) and efficient production of electronically excited states associated with this type of discharge is found to have a profound effect on the consequent kinetics. A process of stepwise dissociation through electron impact of the N 2 (A Σ u + 3

show abstract

Section: Fluorescence Spectramentioning

confidence: 64%

TALIF measurements of atomic nitrogen in the afterglow of a nanosecond capillary discharge

Chng

Lepikhin

Orel

et al. 2020

Plasma Sources Sci. Technol.

View full text Add to dashboard Cite

show abstract

“…Our study here aims further to analyze the processes leading to the depletion of the fluorescing state while using 3 times shorter laser pulses (10 ps). Quadratic regimes have been also achieved when using fs-TALIF in Kr gas by constructing laser sheets so as to significantly decrease I [12,35]. Therefore, our work and the excellent studies [12,14,34,35], contribute to the development of ultrafast TALIF diagnostics for determining absolute densities and quenching coefficients of H and N atoms in reactive plasmas.…”

Section: Resultsmentioning

confidence: 72%

Picosecond two-photon absorption laser-induced fluorescence (ps-TALIF) in krypton: The role of photoionization on the density depletion of the fluorescing state Kr 5p′[3/2]2

et al. 2021

View full text Add to dashboard Cite

The present study focuses on the application of a picosecond (ps) TALIF technique in krypton (Kr) at variable pressure (0.1-10 mbar). The laser intensity (I, units W.cm -2 ) is tuned between 1 and 480 MW.cm -2 , and the depletion of the density of the Kr 5p´[3/2]2 fluorescing state through photoionization (PIN) and amplified stimulated emission (ASE) is investigated. This is done by combining TALIF experiments with a simple 0D numerical model. We demonstrate that for a gas pressure of 3 mbar and 15 < 𝐼 ≤ 480 MW.cm -2 , a saturated fluorescence signal is obtained, which is largely attributed to PIN, ASE being negligible. Also, a broadening of the two-photon absorption line (i.e. 4p 6 1 S0→→5p´[3/2]2) is recorded due to the production of charged species through PIN, inducing a Stark effect. For I≤15 MW.cm -2 , though, PIN is significantly limited, the absorption line is noticeably narrowed, and the quadratic dependence of the TALIF signal intensity versus the laser energy is obtained. Thus, in this case, the investigated Kr TALIF scheme, using the 5p´[3/2]2→5s[3/2]1 fluorescence channel, can be used for calibration purposes in ps-TALIF experiments. These results are of interest for fundamental research since most ps-TALIF studies performed in Kr do not investigate in detail the role of PIN and ASE on the depletion of the Kr 5p´[3/2]2 state density. Moreover, this work contributes to the development of ps-TALIF for determining absolute densities and quenching coefficients of H and N atoms in plasmas. This is useful in numerous plasma-based applications (e.g. thin film synthesis, biomedical treatments, plasma-assisted combustion, …), for which the knowledge of the density/kinetics of reactive atoms is essential.

show abstract

“…This was also confirmed by a time-dependent 2D model capable of simulating unsteady reacting flows. Furthermore, in a more recent study [104], the use of fs-TALIF only in Kr gas allowed the authors to perform single-shot 2D planar images of Kr atoms in a gas cell. The laser pulse duration was of about 80 fs at 1 kHz repetition rate, and the maximum laser pulse energy was of 13 μJ at 204.1 nm (i.e., the two-photon excitation wavelength used for Kr).…”

Section: Ultrafast (Ps/fs) Talifmentioning

confidence: 99%

“…Again, this would result in a significant increase in the laser intensity, possibly leading to photolytic effects and depletion of the laser-excited states by PIN and/or ASE. Therefore, appropriate solutions should be found, e.g., instead of using tightly focused laser beams, to spread the laser energy in a plane (i.e., creating a laser sheet) in order to reduce the laser intensity for the same laser peak pulse power [45,104]. Another effect of a high laser intensity can be the saturation of the optical transition, which is known as power saturation [3].…”

Section: Challenges On the Use Of Fast (Ns) And Ultrafast (Ps/fs) Talmentioning

confidence: 99%

Progresses on the Use of Two-Photon Absorption Laser Induced Fluorescence (TALIF) Diagnostics for Measuring Absolute Atomic Densities in Plasmas and Flames

Lombardi

Aubert

Duluard

et al. 2021

Plasma

View full text Add to dashboard Cite

Recent developments in plasma science and technology have opened new areas of research both for fundamental purposes (e.g., description of key physical phenomena involved in laboratory plasmas) and novel applications (material synthesis, microelectronics, thin film deposition, biomedicine, environment, flow control, to name a few). With the increasing availability of advanced optical diagnostics (fast framing imaging, gas flow visualization, emission/absorption spectroscopy, etc.), a better understanding of the physicochemical processes taking place in different electrical discharges has been achieved. In this direction, the implementation of fast (ns) and ultrafast (ps and fs) lasers has been essential for the precise determination of the electron density and temperature, the axial and radial gradients of electric fields, the gas temperature, and the absolute density of ground-state reactive atoms and molecules in non-equilibrium plasmas. For those species, the use of laser-based spectroscopy has led to their in situ quantification with high temporal and spatial resolution, with excellent sensitivity. The present review is dedicated to the advances of twophoton absorption laser induced fluorescence (TALIF) techniques for the measurement of reactive species densities (particularly atoms such as N, H and O) in a wide range of pressures in plasmas and flames. The requirements for the appropriate implementation of TALIF techniques as well as their fundamental principles are presented based on representative published works. The limitations on the density determination imposed by different factors are also discussed. These may refer to the increasing pressure of the probed medium (leading to a significant collisional quenching of excited states), and other issues originating in the high instantaneous power density of the lasers used (such as photodissociation, amplified stimulated emission, and photoionization, resulting to the saturation of the optical transition of interest).

show abstract

Femtosecond two-photon laser-induced fluorescence of krypton for high-speed flow imaging

Cited by 21 publications

References 14 publications

TALIF measurements of atomic nitrogen in the afterglow of a nanosecond capillary discharge

TALIF measurements of atomic nitrogen in the afterglow of a nanosecond capillary discharge

Picosecond two-photon absorption laser-induced fluorescence (ps-TALIF) in krypton: The role of photoionization on the density depletion of the fluorescing state Kr 5p′[3/2]2

Progresses on the Use of Two-Photon Absorption Laser Induced Fluorescence (TALIF) Diagnostics for Measuring Absolute Atomic Densities in Plasmas and Flames

Contact Info

Product

Resources

About