The spatial distribution of small signal gain in a segmented hollow cathode discharge laser

Adamowicz, Tadeusz M.; Szalai, L.; Rózsa, K.; Kwaśniewski, W.

doi:10.1007/s003400050322

Cited by 9 publications

(5 citation statements)

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“…8͑a͒. The qualitative agreement with experimental data measured for a 780.8 nm SHC copper ion laser 70 ͑having an inner diameter of 8 mm͒ is very good.…”

Section: B Laser Characteristics 1 Small-signal Gainsupporting

confidence: 78%

Au-II 282 nm segmented hollow-cathode laser-parametric studies and modeling

Bánó

Szalai

Horváth

et al. 2002

Journal of Applied Physics

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Laser operation on the Au-II 282.3 nm ultraviolet transition is obtained using a high-voltage segmented hollow-cathode discharge tube. The metal vapor is produced by means of cathode sputtering. A small amount of argon is added to the helium buffer gas in order to achieve higher sputtering yield. Measurements of the laser power and small signal gain indicate that the optimal partial concentration of argon is in the range of 0.25%-0.75%. Quasi-continuous wave output power of 100 mW is obtained from a 34-cm-long active region while the highest small-signal gain is 52% m Ϫ1. To explain the basic features of the laser operation we present a model of the segmented hollow-cathode discharge. All the discharge characteristics are calculated in a self-consistent way except the temperature of slow electrons. The trajectories of fast electrons emitted from the cathode are followed by Monte Carlo simulation. Rate equations of ion, metastable and metal atom densities are solved in the negative glow, while another Monte Carlo code is applied for the fast heavy particles in the cathode sheath. The spatial distribution of the gas temperature and the thermalization of sputtered metal atoms are calculated as well. The laser characteristics predicted by the model are in reasonable agreement with the experimental results.

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“…8͑a͒. The qualitative agreement with experimental data measured for a 780.8 nm SHC copper ion laser 70 ͑having an inner diameter of 8 mm͒ is very good.…”

Section: B Laser Characteristics 1 Small-signal Gainsupporting

confidence: 78%

Au-II 282 nm segmented hollow-cathode laser-parametric studies and modeling

Bánó

Szalai

Horváth

et al. 2002

Journal of Applied Physics

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“…Since the discharge length in each case is the same it must be concluded that the gain distribution throughout the tube cross section depends on the C/A ratio. The results in table 1 and reference [11] support this view.…”

Section: Discussionsupporting

confidence: 57%

“…At 9 mbar the TEM 01 mode is the last to be extinguished in the 2/6 and 2/4 configurations, (pD = 36 mbar mm), which indicates that the pumping is higher closer to the cathodes. A similar asymmetry in the pumping in a SHC, (pD = 56 mbar mm, C/A = 1) is described in [11] which reports a measurement of the spatial distribution of the small-signal gain throughout the tube cross section. That work attributes the double peaked distribution in the gain cross section to a higher density of metal vapour and buffer ions in the regions adjacent to the cathodes.…”

Section: Resultsmentioning

confidence: 60%

“…It is proposed that losses through the 'geometric' sides of the NG in a larger bore, small C/A configuration reduce the He + density and thereby the pumping. Tangible evidence for these losses is provided by the distribution of He + and charge-transfer ionization of Cu atoms throughout the bore of a SHC tube for C/A = 1 implied by the spatial dependence of the small-signal gain [11]. However, it is these losses which force the discharge to run at a higher voltage with concomitant increases in the local rates of buffer gas ionization and sputtering.…”

Section: Discussionmentioning

confidence: 99%

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Dependence of gain and output power on cathode to anode area ratio in a segmented hollow-cathode Cu-II 781 nm laser

Leigh

Tobin

Rózsa

1997

J. Phys. D: Appl. Phys.

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The characteristics of a segmented hollow-cathode He - 781 nm laser are modified by varying the cathode to anode area ratio (C/A), in steps from 3.0 to 0.33, for a fixed bore diameter of 4 mm. The discharge voltage for a given current to pressure ratio, and consequently the small-signal gain and multimode output power for a given current, are significantly increased when C/A is reduced. For a given gain in excess of 20% , the input power decreases slightly as C/A is reduced. However, for a given multimode output power, the input power is almost independent of C/A (0.33 to 2.0). For a gain of 60% the current density decreases from 450 to 340 mA when the area ratio is reduced from 3 to 0.5.

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“…The application of Brewster windows and the possibility to separately control the current in the different elements allows us to measure the gain as a function of current from zero current. However, we have to keep in mind that the gain distribution in the cross section of the discharge depends on the buffer gas pressure and the actual current [23], [24]. At higher pressures, the gain has two maxima near the cathode surfaces due to the high copper concentration there [25]- [28] and the gain is less in the axis of the tube.…”

Section: Resultsmentioning

confidence: 99%

High-gain ultraviolet Cu-II laser in a segmented hollow cathode discharge

Szalai¹,

Rózsa

Ulbel

et al. 1998

IEEE J. Quantum Electron.

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We report measurements of the discharge and laser characteristics of an ultraviolet (UV) copper ion laser radiating on the 248.6-and 270.3-nm transitions. Our 50-cm active length laser operates in a high-voltage segmented hollow cathode discharge with Brewster windows and external mirrors. The lowest threshold currents were 7.3 and 5.6 A for the above transitions, respectively. The threshold current was found to increase with decreasing active length. We obtained superior gain characteristics (to 11.2 and 8.8%/m gain for the 248.6and 270.3-nm transitions, respectively, at 0.3 A/cm linear current density) compared with previous studies on UV Cu ion lasers in conventional hollow cathode discharges.

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The spatial distribution of small signal gain in a segmented hollow cathode discharge laser

Cited by 9 publications

References 0 publications

Au-II 282 nm segmented hollow-cathode laser-parametric studies and modeling

Au-II 282 nm segmented hollow-cathode laser-parametric studies and modeling

Dependence of gain and output power on cathode to anode area ratio in a segmented hollow-cathode Cu-II 781 nm laser

High-gain ultraviolet Cu-II laser in a segmented hollow cathode discharge

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