Linear chromatic dispersion combined prism beam splitting device

Abstract

The invention discloses a linear chromatic dispersion combined prism beam splitting device which is formed by combining two prisms made of a special selected material and provided with coating films on the side faces in the mode of 'bottom surface adhesion and opposite coating film faces'. The linear chromatic dispersion combined prism beam splitting device is especially suitable for spectral analysis, spectrum detection and other relevant fields. Based on a control variable method and a differential equation thought, the non-linear chromatic dispersion of the second prism is utilized to compensate non-linear chromatic dispersion of the first prism so as to obtain the linear chromatic dispersion combined prism beam splitting device by controlling light propagation direction and the shapes of the prisms according to the chromatic dispersion characteristic of a first prism material. The linear chromatic dispersion combined prism beam splitting device overcomes the defect of chromatic dispersion non-linearity of the single prism and has the advantages of being wide in free spectral range, high in light energy utilization rate, good in universality, simple in structure, low in price and the like.

Description

technical field [0001] The present invention relates to a prism light-splitting device, in particular to a linear dispersion combined prism light-splitting device, which is a combined prism composed of two prisms with specially selected materials and side coatings according to the method of "the bottom surfaces are attached to each other, and the coating surfaces are opposite". In spectral detection, analysis and other related fields. Background technique [0002] First of all, it is necessary to clarify such a concept that the dispersion of a material is caused by its refractive index as a function of wavelength. When the refractive index of the material is a function of wavelength, the material has linear dispersion characteristics; when the refractive index of the material is a high-order function of wavelength, the material has nonlinear dispersion characteristics. The dispersion characteristics of a prism are characterized by the relationship between the deflection ang...

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Problems solved by technology

The space remote sensing short-wave infrared imaging spectrometer developed by the Shanghai Institute of Technical Physics for the "Tiangong-1" uses the OASIS system. Although a complex optical system is used, the average spectral resolution of the system only reaches 24nm 【8】 , reflecting that the nonlinear defect of the dispersion of the OASIS system has not been better improved

[0011] The shortcoming of above-mentioned three kinds of prior art is mainly reflected in the following aspects: one, for triangular prism, the refractive index of material causes the angular dispersion rate of triangular prism to present serious non-linearity with the nonlinear variation of wavelength, short-wave (400nm ) part of the angular dispersion rate is dozens of times to hundreds of times the angular dispersion rate of the long-wave (1000nm) part; Second, the Fery prism can achieve linear dispersion in theory, but in practice the angular dispersion of the short-wave part (400nm) of the Fery prism The rate is more than 10 times that of the long-wave (1000nm) partial angular dispersion rate. In addition, the spectroscopic effect of the Fery prism is subject to the processing accuracy, the actual processing is difficult, and the key parameters are difficult to control; 3. For the OASIS system that corrects the nonlinear dispersion of the prism, use The shaft system increases the difficulty and cost of system processing, increases the difficulty of system installation and adjustment, and the nonlinear dispersion of the system is still serious

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