X-ray kinoform lenses made using femtosecond laser technique

Abstract

Using femtosecond laser technique, ‘long type’ kinoform lenses designed with single foci are made for both soft X-ray range(around 800ev) and hard x-ray range(12kev). The soft x-ray lenses are made of SU8 photoresist by two-photon polymerization(TPP) technique while the hard x-ray lens is made of sapphire using femtosecond laser ablation. Physical aperture of the soft X-ray SU8 lenses reaches 90 microns with one centimeter focal length. The hard X-ray sapphire lens has aperture size at around 210 microns but much larger focal length of 5 meters. These lenses show promising usage of ultrafast femtosecond laser in making complicated x-ray lenses though much works are still needed to improve the fabrication process.