Phase correction apodization method for Fourier transform spectrometer

Abstract

The invention relates to a phase correction apodization method for a Fourier transform spectrometer. In the method, by weighting a zero-crossing single-sided interferogram, the errors caused by utilizing data near a zero optical path difference point in the calculation process twice are reduced. The method has better weighting effects than an apodization method provided by Mertz, the accuracy of a recovery spectrum can be ensured, and the calculation complexity is effectively reduced simultaneously. After the zero-crossing single-sided interferogram is weighted by the apodization method provided by the invention, the sum of products of light intensity of two corresponding points with the same optical path difference in a short double side of the zero-crossing single-sided interferogram and respective corresponding twiddle factors is an average value of the sum of the products of the light intensity of the two corresponding points and respective corresponding twiddle factors before weighting. Thus the calculation errors brought by asymmetry of the interferogram are reduced, and a more precise recovery spectrum is obtained.

Description

technical field [0001] The invention relates to the field of phase correction of a spectrometer, in particular to a phase correction apodization method for a Fourier transform spectrometer. Background technique [0002] At present, the Fourier transform spectrometer is an instrument that measures the spectrum by detecting the interference signal and then performing Fourier transform on the interferogram. Ideally, the interferogram is symmetrical about the zero optical path difference, but because it is difficult to detect the interference signal from zero optical path difference, the beam splitter has absorption loss and inhomogeneity, electronic circuit errors, etc., the interferogram appears certain Degree of asymmetry and phase errors reduce detection sensitivity and lead to spectral line distortion. Therefore, the correction of the phase error is an important link in the calculation of the Fourier transform spectrum analyzer. In the phase error correction of the produc...

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Problems solved by technology

[0009] It can be seen that the method of using the apodization function proposed by Mertz to weight the zero-crossing unilateral interferogram has obvious disadvantages: when the asymmetry of the interferogram is serious, this weighting method not only cannot offset the calculation caused by the asymmetry error, it will aggravate the asymmetry and fail to achieve the expected weighting effect

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