Inscription in the glass of efficient Gauss to top-hat converters based on Pancharatnam-Berry phase by high power femtosecond laser pulses

Abstract

Pancharatnam-Berry phase enables various flat special optical elements such as top-hat converters. We present a study on engineering efficient vectorial top-hat converters inscribed in the glass by high-power femtosecond laser pulses. We start with a phase-encoded top-hat converter and demonstrate how its efficiency can be further increased by adjustment of phase masks and various parameters. We use self-organized nanogratings inscribed by a femtosecond laser for the creation of the converter (produced by 'Workshop of Photonics'). Experimental verification of the concept is also presented.