Espectroscopia de cavidade ressonante tipo Ring-DOWN supercontinuum resolvida no tempo para detecção de multicomponentes gasosos / Supercontinuum Cavity Ring-Down Spectroscopy For Simultaneous Detection Of Multicomponent Gases

AUTOR(ES)
FONTE

IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia

DATA DE PUBLICAÇÃO

21/10/2010

RESUMO

In this work, we present a variation of the technique CRDS (Cavity Ring-Down Spectroscopy) to obtain simultaneously a multicomponent absorption spectrum in a broad visible range. This new approach uses the Supercontinuum (SC) spectrum (resulting from irradiation of nonlinear media by femtosecond lasers, or simply generated by compact sources) as a light source to illuminate the cavity. In this context it is described the features of the modules assembling a MC-SC-CRDS (Multicomponent Supercontinuum Cavity Ring-Down Spectroscopy): a set of high refletivity mirrors, the resonant cavity and the detection system. Some problems related to the multimode excitation, stray light, effective use of the dynamic range of the detector, the poor resolution of the instrument to resolve narrow absorption lines are issued. We present the absorption spectra of H2O (polyads 4nu, 4nu + delta ) and O2 (spin-forbidden b-X branch) measured simultaneously by this technique in the visible range and a comparison with the absorption lines based on HITRAN database is made to demonstrate the functionality of this method.

ASSUNTO(S)

cavidade ressonante crds crds espectroscopia resonant cavity spectroscopy supercontinuum supercontinuum

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