Identification of the origins of photoionisation in CO2 tea lasers

S.J. Scott, A.L.S. Smith

Research output: Contribution to journalArticlepeer-review

4 Citations (Scopus)


In sealed CO2 spark preionized lasers, the preionization is largely due to photoionization of NO and NO2; in seeded TEA lasers it originates from the low ionization potential additive used. Unseeded and flowing gas lasers can still be successfully preionized but the source of this preionization has remained a mystery; previous attempts to isolate and identify low I.P. gaseous impurities have failed. These have now been identified, using a combination of cryogenic impurity concentration and mass spectroscopy and found to be a complex mixture of hydrocarbons (C2-C7). Of these hydrocarbons, the alkenes are found to be predominantly responsible for the photoionization and are present in concentrations of about 0.5 ppm. Deliberate addition of one of these alkenes, propene, to a UV preionized CO2 TEA laser was found to enhance the lasers performance at high energy loadings.
Original languageEnglish
Pages (from-to)1-5
Number of pages4
JournalApplied Physics B - Photophysics and Laser Chemistry
Issue number1
Publication statusPublished - Jan 1984


  • carbon dioxide lasers
  • impurities
  • photoionization
  • tea lasers
  • alkanes
  • electric discharges
  • electric sparks
  • hydorcarbons
  • mass spectroposy


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