engleski

Cavity ring-down spectroscopy for atomic hydrogen beam characterization

In Cavity Ring-Down Spectroscopy (CRDS) technique laser pulse oscillates back and forth between highly reflective mirrors. Atoms traversing the cavity waist absorb photons at Doppler shifted frequencies depending on their parallel velocity component. This gives contribution both to the blue and to the red spectral line wing resulting with line profile broadening or even line splitting. Recently we have applied this technique to study laser induced plasma plume [1], [2]. It has been shown that spatial and temporal resolution of the CRDS technique can be used to study plume dynamic performing the forward convolution of measured absorption lineshapes. In the present work we apply the model calculation for the case of atomic hydrogen beam characterization. Typical hydrogen velocity distributions and various angular atom distributions were used for different sets of CRDS observation parameters to calculate Hydrogen alfa absorption line profile at 656 nm. We shall discuss several simple experimental implementations and applications for different hydrogen atomic beam sources. [1] N. Krstulović, N. Čutić and S. Milošević, Modelling of cavity ring-down spectroscopy characterization of laser-induced plasma plume, IEEE Transactions on Plasma Science, in press June 2008 [2] N. Krstulović, N. Čutić and S. Milošević, Spatial and temporal probing of laser induced plasma plume by cavity ring-down spectroscopy, submitted to Spectrochimica Acta Part B 2008.

cavity ring-down spectroscopy; hydrogen beam

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