Formation of Complex and Energy Spectra in Diffraction Spectral Devices: the Radio-Optical Approach

On the basis of radio optics methods, an alternative description of the action of a prism spectral device is proposed, which is based on transformations of an optical signal by an optical coherent Fourier processor. The analyzed optical radiation is introduced into the optical coherent Fourier processor by a dispersing element in the form of a prism. The transmission function of the prism as a transparency and the input-output ratio of the prism spectral device for complex spectra in the form of a linear integral operator, in which the complex instrumental function is determined by the transmission function of the prism, are established. The unified approach to the description of diffraction spectral devices: prismatic and grating is proposed. A feature of this approach is the sequential description of the conversion of the optical signal by all elements of the devices from its input aperture to the result of reading by the photodetector. On the basis of radio optics methods, an alternative description of the operation of diffractive spectral devices and the formation of complex and energy spectra in them is proposed. Diffraction devices (prismatic and grating) are considered in the form of an optical coherent Fourier processor with a dispersing element installed at its input. Dispersing elements (prism and grating) are considered as transparencies, and their transmission functions are obtained. The ratios of input-output of prism and grating devices for complex spectra are established in the form of a linear integral operator, in which the complex instrumental function is determined by the transmission function of the dispersing element. The radio-optical approach made it possible to establish the dependence of the complex instrumental function on the parameters of the optical system of the device, in particular, on the parameters of the dispersing element: a prism or a grating.