Research On Large Aperture Spatial Heterodyne Imaging Spectroscopy

Large aperture spatial heterodyne imaging spectroscopy (LASHIS) is a novel Fourier transform spectroscopy (FTS) with high spectral resolution, high throughput, and high stability. This technology combines the advantages of the large aperture static imaging spectroscopy (LASIS) and the spatial heterodyne spectroscopy (SHS). On the one hand, this technique is based on the large aperture static imaging spectrometer with a pair of parallel gratings introduced in it. This grating pair produces a heterodyned interference frequency and reduces the interference frequency. Thus, a very high spectral resolution can be achieved in a selected spectral band with very little interference sampling points. On the other hand, there is no slit in this system and it is a point-to-point imaging spectrometer. Also, it is based on the common path Sagnac interferometer. It retains the high throughput, high stability advantages of LASIS. LASHIS, with high throughput, high spectral resolution, and high stability advantages, is especially suitable for hyperspectral detection of faint signals and meets the needs of hyperspectral remote sensing. In this thesis, LASHIS is systematically studied. The main contents include:1. The development status of the imaging spectroscopy and its development tendency are summarized. The research status of SHS with high spectral resolution and its applications are introduced.2. After introducing the principles of FTS and SHS, the basic principles of LASHIS are elaborated; the basic theoretical system of LASHIS is established.3. The optical model of LASHIS is set up. The simulated interference image of the Na lamp is generated using ray tracing method from this model. Moreover, an experimental device is built up and the real interference image of the Na lamp is generated from this device. These two results have a good agreement with each other. The bimodal structure of the Na lamp spectrum is recovered use spectral inversion methods. This verified the correctness of the theory of LASHIS.4. Based on the tolerance analysis of the main components of LASHIS. the prototype of LASHIS is designed and developed. The system adjustment method is summarized. The image quality of this prototype is tested using resolution targets, and its spectral calibration is presented using a tunable laser.5. Using the prototype, uniform surface light source and field real push-broom imaging experiments are carried out respectively. The spectral data cube is generated using the data processing method and high resolution spectrums are achieved. The retrieved spectrum consists with the simulated spectrum in MODTRAN.6. A spatial heterodyne spectrometer based on the Mach-Zehnder interferometer is proposed, the basic principle of this spectrometer is described. Its optical model is set up. The frequency of the interference pattern and its corresponding incident wavelength has a perfectly linear relationship. Thus, wide spectral band detection can be achieved. Also, it has dual light output characteristics.