• Title, Summary, Keyword: Optogalvanic effect

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Observation of Penning ionization using the optogalvanic effect

  • Jeong, Kee-Ju;Lee, Jun-Hoi
    • Journal of Korean Vacuum Science & Technology
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    • v.7 no.1
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    • pp.18-22
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    • 2003
  • The optogalvanic effect is proposed and demonstrated as a technique for Penning ionization in a discharge of mixtures of metal vapors and rare gases. The gadolinium and argon mixture is used as a prototype. The lowest metastable of argon, 3P$_2$ (ls$\_$5/ in Paschen notation) at 93144 cm$\^$-1/, is within kT from the excited states of Gd ion. Thus Penning ionization occurs to an excited states of the ion. This process strongly alters the optogalvanic signal and has its own signatures.

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Wavelength Measurement of Pulsed Tunable Laser Using Optogalvanic Effect (Optogalvanic 효과를 이용한 펄스형 파장가변 레이저의 파장측정)

  • 정의창
    • Korean Journal of Optics and Photonics
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    • v.4 no.2
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    • pp.181-187
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    • 1993
  • Optogalvanic spectrum of Ne has been obtained in the visible wavelength region 550-600 nm by using pulsed tunable dye laser. The recorded laser wavelengths are calibrated on the basis of the accurately-known Ne atomic transition lines. The accuracy of the measured wavelength is ${\pm}$ 0.005 nm. We tabulated the wavelengths and the relative intensities of the OG signals which are useful to calibrate the dye laser using R-590, R-610 dyes.

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Observation of Negative Resistance Region in Voltage-current Curve of Hollow Cathode Discharge (속이 빈 원통형음극 방전의 전압-전류 곡선에서 음 저항 영역 관찰)

  • Lee, Jun-Hoi;Lee, Sung-Jik
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.18 no.9
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    • pp.870-875
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    • 2005
  • We measured the optogalvanic signal and discharge voltage-current(V-I) curve under the two different discharge conditions with different buffer gases, Ar, and Ne. When the Gd was used as a cathode material at low discharge current less than 10mA, a significant change was observed in the current-voltage curve. Time resolved optogalvanic signal measurement were measured by the diode laser of which wavelengths correspond to metastable transition line of these gases (Ar, Ne). From these measurements, we found that the characteristics of the V-I curve strongly depend on the Penning ionization process.

Laser doppler velocimetry using the optogalvanic effect of $Co_2$ laser (광전류 효과를 이용한 $Co_2$ 레이저 도플러 속도 측정기)

  • 최종운;김용평;김윤명
    • Korean Journal of Optics and Photonics
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    • v.8 no.6
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    • pp.482-485
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    • 1997
  • A new laser Doppler velocimeter employing a $CO_2$laser has been developed by using its optogalvanic effect. A change in the electric impedance of a discharge, induced by mixing of a returned wave with an originally existing wave inside the cavity, was employed to detect the Doppler frequency shift. A Doppler frequency shift as much as 60 KHz was detected, and also a good linear relationship between the velocity and the Doppler frequency shift was obtained.

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Measurement of Ar Temperature of Hollow Cathode Discharge Plasma

  • Lee, Jun-Hoi;Shin, Jae-Soo;Lee, Sung-Jik;Lee, Min-Soo
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.18 no.4
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    • pp.381-385
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    • 2005
  • The plasma temperature of Ar gas in hollow cathode discharge were measured. This is done by measuring the line profile of the 1s/sub 8/-2p/sub 8/ transition in Ar, using a single-frequency diode laser. Low power diode lasers have been successfully used for investigation of the line profiles of Ar transitions in hollow cathode discharges. It turns out that the plasma temperature of Ar is 640∼783 K in the discharge current range at 7∼10 mA.