Bruker Optik Gmbh

Christian Hepp

Stephan Luettjohann

A method for measuring and determining a THz spectrum of a sample () having an improved spectral resolution. Two laser beams () are superimposed, such that two parts () of a superimposed laser radiation are generated, which have a beat frequency in the THz range. The first part () is introduced into an emitter () for generating a THz radiation (), which passes through the sample. The characteristic transmission radiation () thus obtained is forwarded to a detector (), which is activated by the second part () of the superimposed laser radiation. By repetition with different beat frequencies, a measurement signal I(f) of the form I(f)=A(f)&#xb7;cos [&#x3a6;(f)] is obtained for the sample. An auxiliary signal &#x128;(f) shifted by 90&#xb0; is determined from the measurement signal I(f), with &#x128;(f)=A(f)&#xb7;cos [&#x3a6;(f)&#xb1;90&#xb0;]. The THz spectrum S(f) of the sample is determined by the auxiliary signal &#x128;(f), with S(f)=|z(f)|=|I(f)+i&#x128;(f)|.

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Gaggenau, Germany

Christian Hepp