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CRDS: Cavity Ring Down Spectroscopy

Description: A type of absorbtion spectroscopy used to measure the concentration of species in liquid or gaseous samples

Recommended Product: Quantel Brio

  • Summary
    1. CRDS is used for 10 years
    2. Non intrusive measurement
    3. Highly sensitive and quantitative method
  • Basics
    1. Measuring the life time of a photon in a resonant cavity, where a liquid or gazeous sample is placed

Brio 2w/3w for CRDS and LIBS

(Courtesy of CORIA-Rouen 2005)

  • Advantages of the method
    1. non sensitive to laser pulse to pulse fluctuations
    2. Applicable on non fluorescent species
    3. Quite simple theory
    4. High sensitivity (Typ. 10-5 to 10-10 cm-¹)
  • Can be coupled with LIF
  • An optical feedback can be implemented to adjust the mode matching between the laser pulse and the cavity length
    => OF-CRDS
    => OF-CEAS Cavity Enhanced Absorption Spectroscopy

  • Fields of application
    1. Flame analysis
      1. Optimization of the gaz seeders in automotive engines
      2. Mapping of the different elements (effective sections of absorption change w/ the wavelength) in a laminar flame, as function of the distance to the burner
    1. Trace analysis
    2. Environmental survey