Principle of direct-inscribing diffractive phase elements by linearly polarized light

A novel method for fabricating diffractive phase elements on azobenezene polymer film is proposed. Distinguished from the common direct-inscribing systems, polarized light illuminates on sample films in this polarized-light direct-inscribing system. By composite control of the intensity and polarization direction of the inscribing light and exposure time, a special phase-delay distribution graph can be achieved. Based on the proposal, a series of phase-type gratings were produced. Our speculation was supported by polarizing optical microscopy and scanning near-field optical microscopy (SNOM). Some qualitative analyses were made in the article. Compared with the holographic interference method, the one above is more flexible, and undemanding for the experimental environment. It may get extensive application.