HP Labs Technical Reports

Suppression of Interference Effects in Spectroscopy Using an Integrating Sphere

Owen, Geraint

HPL-96-69

Keyword(s): spectroscopy, thin film

Abstract: Interference effects occur in the optical spectroscopy of thin film samples, and they can obliterate absorption spectra, especially if these are weak. A novel solution to this problem is proposed: it involves placing the sample inside an integrated sphere and then collecting both reflected and transmitted light simultaneously. The effectiveness of this technique has been demonstrated experimentally, and absorption dips as weak as 2.4x10(to the minus 4 power) have been measured. A further attribute of the method is that some of the light reflected from the walls of the sphere is redirected back towards the sample, thus increasing its absorption by a substantial factor.

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