Design of optical system for fiber optic spectrometer based on holographic optical elements

Based on the theory of holographic optics, we analyzed the Gaussian imaging properties of holographic optical elements, including the optical focal power, position of imaging and diffraction efficiency, verified its feasibility to be a grating for the spectrometer. Based on the above theory and the spectrometer work principle,we designed the optical system, and through the simulation, image quality evaluation and optimization with Zemax，the final result was got. The parameters of holographic grating were as follows: the recording wavelength was 575nm,the angle between the recording beams (a planar wave beam and a spherical wave beam)was 100, the focal length was 40mm, the used diffracted light was +1 order , the aperture was 10 mm；The parameters of spectrometer were as follows：the range of work wavelength was 400 nm~800 nm, the volume was 140 mm30 mm40 mm,the width of spectrum was 29.1 mm. Finally,we built the light path on the optical platform, used the circuit system and the spectrometer software that were developed completely to collect mercury lamp spectrum. Testing results show the spectral resolution is better than 8 nm，the mercury spectra obtained are the same with the standard one, indicating that the optical system designed based on holographic optics is feasible.