One- and two-photon laser optogalvanic spectroscopy of neon in the 570–626nm region (original) (raw)
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Two-photon time-resolved optogalvanic signals of neon
Optics Communications, 2009
In this work, temporal evolution of two-photon laser optogalvanic signals of neon has been studied. Optogalvanic signals for four transitions from the metastable 2p 5 3s[3/2] 2 state to 2p 5 4d 0 [3/2] 1 , 2p 5 4d 0 [3/2] 2 , 2p 5 4d 0 [5/2] 3 and 2p 5 4d 0 [5/2] 2 states were recorded over a range of discharge currents (3.4-9 mA). It was found that the shape of the optogalvanic signal was strongly dependent on the discharge current so that its peak shifted to shorter times and its amplitude increased with the discharge current. The decay rates of the 4d states, calculated from the optogalvanic signals, were found to increase linearly with the discharge current in the range of 6.2-9 mA. However, for the range of 3.4-5.4 mA, the decay rates were observed to slightly decrease with the discharge current.
The study of dominant physical processes in the time-resolved optogalvanic spectra of neon
European Physical Journal D, 2005
We present the dominant physical processes responsible for the production of the optogalvanic signal in the spectra of neon. We have investigated the effects on the optogalvanic signal by scanning a dye laser across the neon transitions in the DC discharge plasma. Time-resolved spectra are obtained at a fixed wavelength of the dye laser resonantly tuned to an optically allowed transition. The temporal evolutions of the signals are registered on a storage oscilloscope. Three transitions from the 3s[1/2]2 metastable state corresponding to the ΔJ = ΔK = 0, ±1 dipole selection rules have been selected to investigate the dominant physical processes responsible for the optogalvanic signals. The change in the signal amplitude as a function of the discharge current has been registered. In addition the electron collisional ionization rate parameter ratios have been determined for the transitions corresponding to dipole selection rules ΔJ = ΔK = -1, ΔJ = ΔK = 1 and ΔJ = ΔK = 0, as 1.63, 1.75 and 1.0 respectively. The effective lifetimes of the upper levels involved in the aforementioned transitions are also calculated as 62.5 μs, 31.25 μs and 12.85 μs respectively.
Journal of the Optical Society of America B, 1996
A model based on rate equations has been developed to describe the optogalvanic signal observed in the negative-glow region of a hollow-cathode discharge when a pulsed dye laser is tuned to the 1s 5 -2p 4 and 1s 2 -2p 1 neon transitions (Paschen notation). We include an ambipolarlike term of charge loss that is determined empirically and a term that takes into account the variation of photoelectrons produced by changes in the 1s 2 population on laser irradiation. The change of sign of the signal for transitions from the 1s 2 level with respect to those from the 1s 5 state, the amplitude, and the time evolution are well predicted.
The study of optogalvanic effect associated with the 1s states of neon
Journal of Molecular Structure, 2008
We report on the temporal evolution of the optogalvanic signals in neon using a commercial hollow cathode lamp in conjunction with a Nd:YAG pumped dye laser system. We have recorded transitions excited from each of the neon 1s states over a range of discharge current to investigate the dominant physical processes responsible for the optogalvanic effect in neon discharges. The decay rates associated with the four 1s levels have been obtained using a mathematical rate equation model. A linear relationship between the decay rates and the discharge current has been found and the effective lifetimes and the electron collisional rate parameters of the 1s levels have been determined.
On the Time Resolved Optogalvanic Spectroscopy of Neon in a Hollow Cathode Discharge
Journal of Nano- and Electronic Physics, 2021
Time resolved optogalvanic (OG) signals of 1s4-2p8 (650.65 nm) and 1s3-2p7 (653.29 nm) transitions have been studied in neon DC plasma. Numerical fit of the signals based on four-term rate equation model has been used to elucidate the contributions to the signal from four 1si levels. Evolution of decay rates of four 1si neon states as a function of discharge current has been studied. The dominant discharge processes for the first transition were photoionization and impact ionization, while for the second transition-the metastable-metastable collisional ionization mechanism was added to the previously mentioned mechanisms to produce the OG signal. The effective lifetimes of the 1si states have been determined for both transitions, where 2 s is found for the resonance state 1s2, while the 1s3,4,5 have an almost equivalent effective lifetime of 40 s. The long effective lifetime of all 1s2,4 states in comparison with their radiative lifetimes is attributed to the radiation trapping effect. The contribution of the 1si states to the OG signals has been studied. 1s3 state involvement was most important in the 1s3-2p7 transition signal, while the 1s4 state has a large contribution to the 1s4-2p8 transition signal.
The study of the 1s4–2pj optogalvanic transients in a neon discharge plasma
Optics Communications, 2009
Time dependent optogalvanic signals induced by the 1s 4 ? 2p j laser excitations have been studied in neon DC plasma. The decay rates related to all the four 1s i levels have been derived by fitting the waveforms with a mathematical rate equation model. The temporal signatures of three transitions namely 638.3, 650.7 and 724.5 nm related to the 2p 7 , 2p 8 and 2p 10 upper levels, respectively, have been found to be different from the rest of the transitions. We relate these effects to the population redistribution of decaying channels and to the processes responsible for the optogalvanic effect.
Doppler-free two-photon optogalvanic spectroscopy
Optics Letters, 1979
We describe the use of a new Doppler-free technique, two-photon optogalvanic spectroscopy (TOGS) in the observation of thirteen transitions from the four levels in the 3s configuration of 2 0 Ne. The transitions from the two nonmetastable 3s levels are the first Doppler-free two-photon transitions reported from energy levels other than ground or metastable levels. This is also the first report 4d[5/2j J = 3 splitting in 20 Ne.