Testing and development of a mobile Fourier transform infrared spectrometer system for the analysis of atmospheric pollutants

1992 ◽  
Author(s):  
Mark R. Witkowski ◽  
Charles T. Chaffin, Jr. ◽  
Timothy L. Marshall ◽  
Martin L. Spartz ◽  
Jonathan H. Fateley ◽  
...  
Keyword(s):  
Fourier Transform ◽  
Fourier Transform Infrared ◽  
Atmospheric Pollutants ◽  
Fourier Transform Infrared Spectrometer ◽  
Infrared Spectrometer ◽  
Spectrometer System

Broadband terahertz dielectric measurement based on multi-beam interference and Fourier transform infrared spectrometer

2018 ◽  
Vol 32 (25) ◽  
pp. 1850298
Author(s):  
Jie Shi ◽  
Mao-Rong Wang ◽  
Kai Zhong ◽  
Chu Liu ◽  
Jia-Lin Mei ◽  
...  
Keyword(s):  
Fourier Transform ◽  
Room Temperature ◽  
Fourier Transform Infrared ◽  
Refraction Index ◽  
Good Alternative ◽  
Dielectric Measurement ◽  
Terahertz Time Domain Spectroscopy ◽  
Fourier Transform Infrared Spectrometer ◽  
Limited Frequency ◽  
Infrared Spectrometer

We demonstrate a method for obtaining optical coefficients over a broad terahertz spectral range from 1.5 THz to 16 THz at room temperature. Based on the interferograms directly acquired by a Fourier transform infrared spectrometer (FTIR), multi-beam interference principle combining Fresnel’s formula is employed to extract the refraction index and the extinction coefficient, giving the basis for calculating dielectric coefficients. It avoids the uncertainty and phase instability while using Kramers–Kronig (KK) relations and overcomes the limited frequency range of terahertz time-domain spectroscopy (TDS). Moreover, this method has better stability and is needless of cutting useful information between neighboring interference peaks for thin samples compared with TDS, making it a general processing method for interferograms and a good alternative for terahertz dielectric measurement.

scholarly journals Intensity Simulation of a Fourier Transform Infrared Spectrometer

Sensors ◽  
2020 ◽  
Vol 20 (7) ◽  
pp. 1833 ◽  
Author(s):  
Zhuoya Ni ◽  
Qifeng Lu ◽  
Yishu Xu ◽  
Hongyuan Huo
Keyword(s):  
Fourier Transform ◽  
Brightness Temperature ◽  
Michelson Interferometer ◽  
Fourier Transform Infrared ◽  
Core Element ◽  
Simulation Process ◽  
Fourier Transform Infrared Spectrometer ◽  
Infrared Spectrometer ◽  
Input Spectrum ◽  
The Fourier Transform

This paper introduces an intensity simulation for the Fourier transform infrared spectrometer whose core element is the Michelson interferometer to provide support for the on-orbit monitoring of the instrument and to improve the data processing and application of the Fourier transform spectrometer. The Geostationary Interferometric Infrared Imager (GIIRS) aboard on Fengyun-4B (FY-4B) satellite, which will be launched in 2020, aims to provide hyperspectral infrared observations. An intensity simulation of the Michelson interferometer based on the GIIRS’s instrument parameters is systematically analyzed in this paper. Off-axis effects and non-linearity response are two important factors to be considered in this simulation. Off-axis effects mainly cause the wavenumber shift to induce a large brightness temperature error compared with the input spectrum, and the non-linearity response reduces the energy received by the detector. Then, off-axis effects and a non-linearity response are added to the input spectrum successively to obtain the final spectrum. Off-axis correction and non-linearity correction are also developed to give a full simulation process. Comparing the corrected spectrum with the input spectrum, we can see that the brightness temperature errors have a magnitude of 10−3 K, and this fully proves the reliability and rationality of the whole simulation process.

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