The Study On Optical Design And Optimization Of Concentric Imaging Spectrometers

Imaging spectrometers integrate imaging techniques with spectroscopic techniques, which can simultaneously acquire the spatial information and spectral information of the target, and combine them into one information cube. It can achieve the timing, location, quantity and quality characteristics of the target, and solves the problem of "no spectral imaging" and "non-spectral imaging" in the traditional fields of optical science.Compared with the traditional imaging spectrometer with grating or prism in a collimated beam, concentric imaging spectrometer can correct the spectral smile and keystone well, and has the advantages of flat image field, miniaturization, light weight. Concentric imaging spectrometer is adapt to a variety of remote sensing platforms, has been widely applied to the areas such as military reconnaissance, resource exploration, environmental monitoring and astronomical observations. The grating concentric imaging spectrometer is compact and convenient to align, but the wide-band, high diffraction efficiency grating is too difficult to produced. As the concentric imaging spectrometer dispersive element, prism has large undisturbed spectral and high spectral transmittance efficiency, which has received public attention and has been better researched. However, the spectral dispersion of prism is strongly nonlinear, which is increase the spectral calibration and decrease the spectral sensitivity. In addition, as to achieve the fidelity, high spatial resolution imaging from fore-optics, need to further studies according to the characteristics for spectral Imaging Systems.In the view of this, the concentric imaging spectrometer optical system is in-depth studied in this thesis. The main contents include the following aspects:First, based on the theory of geometric aberration and wavefront aberration, and the use of ray-tracing method, the aberration analysis model of concentric imaging spectrometer is established. The impact of structural parameters and dispersive element parameters on concentric imaging spectrometer aberration are analyzed, deepening the understanding of the concentric imaging spectrometer system. It provides a theoretical guidance for the optical design of concentric imaging spectrometer.Second, an Offner convex grating imaging spectrometer optical system and a Dyson concave grating imaging spectrometer optical system are designed. And the prototypes are fabricated.Third, concentric imaging spectrometer optical systems with achromatic Fery prisms are designed to decrease the nonlinear dispersion of spectrum, which have large undisturbed spectral and high spectral transmittance efficiency.Fourth, for different applications, different fore-optics are designed, and by integrated optimization to meet the requirements of high image quality, flat field and high spectral resolution.These studies are conducted for the laboratory portable curved grating imaging spectrometer, but they are also provide a theoretical basis and design basis of future airborne concentric imaging spectrometer and spaceborne concentric imaging spectrometer.