Simple analytical expressions for the optical extraction efficiency from COILs with different kinds of resonators

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2 Scopus citations


It is shown that the celebrated Rigrod model (W.W. Rigrod, J. Appl. Phys., 34, 2602 (1963)) is inadequate for calculating the output power of gas-flow lasers in an important range of parameters where the quenching of the excited species is slow and the optical extraction efficiency is high. For both two level systems and chemical oxygen-iodine lasers (COIL) very simple analytic formulae for the output power are obtained which should be used instead of the Rigrod model. The formulae are given for Fabry-Perot, stable and unstable resonators. Both the saturation parameter and the extraction efficiency differ from those appearing in the Rigrod model. The highest extraction efficiency (greater than that calculated by the Rigrod model) can be achieved for both stable and unstable resonators with uniform intensity distribution over the cross section. The extraction efficiency of unstable resonators can be substantially increased by increasing the length of the part of the mirrors lying downstream of the optical axis. The derived formulae are applied to describe the experimental dependence of the power of the RotoCOIL on the threshold gain and to estimate the plenum yield of singlet oxygen. Estimated values of the yield are in better agreement with experimental measurements than that obtained by the Rigrod model.

Original languageEnglish
StatePublished - 1 Jan 1995
Event26th Plasmadynamics and Lasers Conference, 1995 - San Diego, United States
Duration: 19 Jun 199522 Jun 1995


Conference26th Plasmadynamics and Lasers Conference, 1995
Country/TerritoryUnited States
CitySan Diego

ASJC Scopus subject areas

  • General Engineering


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