Holographic grating made of two-wavelength water-resistant photopolymer

The double-layer holographic grating made of a new kind of water-resisting photopolymer which is sensitive to the blue light of 488nm and red light of 632.8nm is introduced. Based on the experimental data and theoretical analysis, the characteristics of the material are investigated. The analysis shows that the resolution of this grating is above 5000line/mm and its diffraction efficiency is above 90%. The central wavelength drifting of the grating is nearly zero when temperature changes. The grating has many merits, such as one-step forming, low loss, etc. The doublelayer holographic grating is suitable for fabricating the wavelength-division multiplexer. The crosstalk question caused by the light coherence has been solved by the technology, and the crosstalk is smaller in comparison with the single-wavelength double-layer grating. During the production of the grating, two incident modes of beam can be chosen arbitrarily, which is oblique incidence and parallel incidence. It has the characteristics of wavelength selection and angle selection.