Discharge instabilities initiated by nonuniform laser extraction in electron-beam sustained discharge KrF lasers

Journal Article · Wed Jul 01 04:00:00 EDT 1987 · J. Appl. Phys.; (United States)

DOI:https://doi.org/10.1063/1.339166· OSTI ID:6537944

Kushner, M J

The photon energy of KrF lasers (lambda = 248 nm) is sufficiently large to photodetach electrons from the halogen negative ion (F/sup -/) and to photoionize excited states of krypton. In electron-beam (e-beam) sustained discharge KrF lasers, the contribution of photogenerated electrons to the total rate of ionization can be large enough to significantly perturb the conductivity of the plasma. If laser oscillation is spatially nonuniform, the photoelectron contribution to the conductivity deforms the local electric field. This condition can ultimately lead to a local discharge ionization instability and an arclike termination of the discharge. In this paper, the effect of nonuniform optical extraction on the discharge stability of an e-beam sustained discharge KrF laser will be studied with results from a two-dimensional time-dependent discharge kinetics and laser extraction model. Examples of stable and unstable configurations will be presented. The time at which the arclike ionization instability terminates the discharge correlates with the time that multistep ionization becomes an appreciable fraction of the total rate of ionization. A criterion for discharge stability is proposed; gradients in conductivity caused by photogenerated electrons must be either perpendicular or parallel to the bulk electric field.

• Research Organization: University of Illinois, Department of Electrical and Computer Engineering, Gaseous Electronics Laboratory, 607 East Healey, Champaign, Illinois 61820
• OSTI ID: 6537944
• Journal Information: J. Appl. Phys.; (United States), Journal Name: J. Appl. Phys.; (United States) Vol. 62:1; ISSN JAPIA
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
420300* -- Engineering-- Lasers-- (-1989)
BEAMS
ELECTRIC DISCHARGES
ELECTRICAL PUMPING
ELECTRON BEAM PUMPING
ELECTRON BEAMS
ELEMENTARY PARTICLES
ELEMENTS
EXCIMER LASERS
FLUIDS
FLUORIDES
FLUORINE COMPOUNDS
GAS LASERS
GASES
HALIDES
HALOGEN COMPOUNDS
INSTABILITY
IONIZATION
KINETICS
KRYPTON
KRYPTON COMPOUNDS
KRYPTON FLUORIDES
LASERS
LEPTON BEAMS
MASSLESS PARTICLES
NONMETALS
PARTICLE BEAMS
PHOTOIONIZATION
PHOTONS
PUMPING
RARE GAS COMPOUNDS
RARE GASES
STABILITY