Femtosecond spectral pulse shaping with holographic gratings recorded in photopolymerizable glasses.

ABSTRACT

The majority of the applications of ultrashort laser pulses require a control of its spectral bandwidth. In this paper we show the capability of volume phase holographic gratings recorded in photopolymerizable glasses for spectral pulse reshaping of ultrashort laser pulses originated in an Amplified Ti Sapphire laser system and its second harmonic. Gratings with high laser induce damage threshold (LIDT) allowing wide spectral bandwidth operability satisfy these demands. We have performed LIDT testing in the photopolymerizable glass showing that the sample remains unaltered after more than 10 million pulses with 0,75 TW/cm2 at 1 KHz repetition rate. Furthermore, it has been developed a theoretical model, as an extension of the Kogelnik's theory, providing key gratings design for bandwidth operability. The main features of the diffracted beams are in agreement with the model, showing that non-linear effects are negligible in this material up to the fluence threshold for laser induced damage. The high versatility of the grating design along with the excellent LIDT indicates that this material is a promising candidate for ultrashort laser pulses manipulations.