Talbot Effect from Rotational Symmetry Gratings: Application to 3D Refractive Grating Formation

Abstract

We report the first observation of Talbot effect – diffraction grating images self-replications at regular distances, from 1D annular grating with the period of d = 30 ± 1 μm. Up to 20 high contrast revivals of the grating were observed by the green laser beam at λ = 532 nm with Talbot distance Z_T = d²/λ = 1.57 ± 0.01 mm. The grating self imaging with half period of the original grating at Z_T/2 was also observed. Using the annular grating as a mask, the recording of refractive index photonic lattice in 2 mm thick Fe doped lithium niobate crystal was performed by 532 nm laser beam. The replication of the grating images due to Talbot effect provides the recording of two refractive replicas of the grating with the periods of d and d/2 inside the 2 mm crystal checked by phase microscope depth scan observations. The obtained results show the possibility of the use of 2D masks for the creation of 3D photonic lattices in photorefractive materials, which can be used as photonic crystals.

Keywords:

• diffraction gratings
• laser
• photonic lattice
• Talbot effect

Acknowledgments

This work is supported by International Science and Technology Center Grant, Project A-1517.