Generating optical vortex with computer-generated hologram fabricated inside glass by femtosecond laser pulses

We introduce a novel method to generate the optical vortex with computer-generated hologram (CGH) fabricated inside glass by femtosecond laser pulses. The CGH was directly written inside glass by femtosecond laser pulses induced microexplosion without any pre- or post-treatment of the material. We also realized the restructured optical vortex beams of both the transmission and reflection pattern with high fidelity using a collimated He–Ne laser beam. The total diffractive efficiency of both the transmission and reflection pattern is about 4.79%.