Abstract: A method for measuring and determining a THz spectrum of a sample (17) having an improved spectral resolution. Two laser beams (1a, 2a) are superimposed, such that two parts (11, 12) of a superimposed laser radiation are generated, which have a beat frequency in the THz range. The first part (11) is introduced into an emitter (13) for generating a THz radiation (14), which passes through the sample. The characteristic transmission radiation (18) thus obtained is forwarded to a detector (15), which is activated by the second part (12) of the superimposed laser radiation. By repetition with different beat frequencies, a measurement signal I(f) of the form I(f)=A(f)·cos [?(f)] is obtained for the sample. An auxiliary signal ?(f) shifted by 90° is determined from the measurement signal I(f), with ?(f)=A(f)·cos [?(f)±90°]. The THz spectrum S(f) of the sample is determined by the auxiliary signal ?(f), with S(f)=|z(f)|=|I(f)+i?(f)|.

Abstract: The invention relates to a method for measuring and determining a THz spectrum of a sample (17), wherein two laser beams (1a, 2a) are superimposed, such that two parts (11, 12) of a superimposed laser radiation are generated, which have a beat frequency in the THz range, wherein the first part (11) is introduced into an emitter (13) for generating a THz radiation (14), wherein the THz radiation (14) passes through the sample (17) and the characteristic transmission radiation (18) thus obtained is forwarded to a detector (15), wherein the detector (15) is activated by the second part (12) of the superimposed laser radiation, wherein, by repetition with different beat frequencies, a measurement signal I(f) of the form I(f)=A(f)·cos[?(f)] is obtained for the sample (17), wherein an auxiliary signal ?(f) shifted by 90° is determined from the measurement signal I(f), with ?(f)=A(f)·cos[?(f)±90°], and wherein the THz spectrum S(f) of the sample (17) is determined by means of the auxiliary signal ?(f), with S(f)