Studies Of Fourier Transform Spectroscopy For Uv And Vuv

The survey of research and development about Fourier transform spectroscopy is summarized firstly in Chapter One of this dissertation. The structures, performance and principle of several kinds of Fourier transform spectrometers which are used in ultraviolet, vacuum ultraviolet and soft X-ray regions are described emphatically and the applications of high resolution Fourier transform spectrometer are further elaborated. The needs to extend Fourier transform spectroscopy to the short wavelength optical region and the main technical difficulties involved are discussed systematically. The main research content of dissertation is presented finally. In Chapter Two, some factors which effect spectral resolution and position shifts of lines are discussed and analyzed according to the basic principle of Fourier transform spectrometer. Numerical simulations of spectral line is given by using a kind of FFT algorithm for large number data and the characteristic of multiplex in the short wavelength region is debated at the end of this chapter. The developed experimental installation of Fourier transform spectrometer for ultraviolet and vacuum ultraviolet regions is described in Chapter Three, it has the advantages of high resolution, high precision, wide spectral region and compact. At first, the design for optical structure is put forward. The mechanisms and structures of beamsplitter/recombiner and catseye retrorefiector are investigated, the reason why stabilized laser is utilized to be reference light source in spectrometer is analyzed. Secondly, the experimental investigation which used A1 +MgF2 as beamsplitter coatings in ultraviolet and vacuum ultraviolet are carried out based on the practical requirement of beamsplitter of Fourier transform spectrometer during development. The probabilities of film layers material selection and structure design have been analyzed by means of some numerical calculations. We have developed an instrument employing Seya-Namioka monochromator, mainly for measuring the spectral properties of beamsplitter films grown on ultraviolet fused quartz substrate at an incident angle of 5 degrees. The results of measurement are discussed. This work extends the area of application of Al + MgF2 coatings. The electronic circuits used to sample and record the light source interferogram are presented, it is consisted of amplifiers, bandpass filter,automatic gain control, phase locked loop units and so on. Electrical simulation has been performed by means of photoelectric insulated A/D sampling converter. The importance of driving mirror smoothly used in Fourier transform spectrometer is discussed. We have designed and used high precision pneumatic hydraulic servo system to move catseye movable mirror in Fourier transform spectrometer. The spectrum of source in ZYGO interferometer is measured by use of this system, and the result conforms to theory. The method of data processing for interferogram is discribed in Chapter Four. The interferogram of a mercury lamp has been measured in experiment by means of ultraviolet Fourier transform spectrometer in developing. The apodization function that we have chosen is four-term Blackman-Harris window function and a fitting polynomial has been used for phase correction of Fourier transform spectra based on the least square method. The ultraviolet emission lines of high precision have been obtained by use of this method. The performances of spectrometer and the program of data processing for interferogram are tested and verified through experiments. The measuring range is in the wavelength region from 170nm to 600nm. The spectral resolution of transformed spectrum is better than l.5×105 at 300nm and wavelength accuracy of this Fourier transform spectrometer is in the range from 0.0002nm to 0.009nm over the spectral region 280nm to 600nm. The devices including vacuum tank and Wilson seal system used to measuring the spectra in vacuum ultraviolet are sho...