Abstract

The use of contact- and optical-projection techniques for recording low-spatial-frequency Raman-Nath-regime phase gratings in LiNbO₃ has been characterized.¹ By using the contact method, gratings have been recorded with periods ranging 50-200 μm that produced as many as 40 diffracted orders when probed by a low-power He—Ne laser. An optical-projection technique using unit magnification has also been used to produce phase gratings of similar periods. Both processes made use of the bulk photovoltaic effect as the primary transport mechanism. Diffraction efficiencies on the order of 20% in the first diffraction order were achieved by means of these techniques. General descriptions of the experimental arrangements used for projection recording will be presented.

© 1990 Optical Society of America