Dynamics of Diffraction Efficiency of Superimposed Volume Reflection Holograms at Their Simultaneous Recording in Photopolymer Material

Abstract—The new experimental data on the dynamics of diffraction efficiency (DE) of superimposed volume reflection holograms with a grating period of ${\sim}$250 nm is obtained at their simultaneous recording in the photopolymer material BAYFOL HX TP. The character and parameters of their interaction are established when exposure of one hologram is delayed relative to the other one. It is revealed that the DE dynamics is practically not affected by variations in diffusion time of monomer in the range $0.12<t_{D}<0.17$ s, but the transient behavior of the photopolymerization parameter $\tau_{p}$, which increased in our experiments from 5 to 15 s, becomes considerably visible. The well-known equations of the photoinduced variation in the photopolymer refraction index are improved with account for the character of variation in the parameter $\tau_{p}$. The calculated dependences of DE dynamics obtained with refined formulas are in good agreement with experimental data (mean square deviation is ${\sim}2\%$).