A theoretical and experimental study on the spectral secondary peak characteristics of holographic reflection gratings

Abstract

This paper analyzes the reflection index modulation distribution and the corresponding spectrum characteristic of the holographic reflection gratings fabricated by Lippman light path under the condition of recording medium absorption being taken into account. The emphasis of discussion is placed on the relationship of secondary peak characteristic of the holographic reflection gratings, bandwidth and the distribution of refraction index modulation under this recording condition, calculating and simulating the distribution curve of refraction index modulation and the corresponding spectrum characteristic curve of diffraction gratings, and the comparison with the holograph gratings recorded by symmetrical light path. The result of calculation shows that there is obvious difference between the spectrum characteristic curve of Lippman holographic gating and that of symmetrical light path, and the secondary peak value of Lippman holographic gratings is lower than that of symmetric light path under the condition of the same reflection index modulation, while the medium of recording is thicker (thicker than 60μm) or the non-linear modulation of refraction index is relatively large, and the higher secondary peak of Lippman holographic gratings presents saw-like and non-degressive, whereas this phenomenon has never occurred in the holographic gratings diffraction recorded by the symmetrical path. This result obtained by calculation and simulation is consistent with experimental result.