The manipulation of structured light beams requires simultaneous spatial modulation of amplitude and phase. Based on the double-phase holography (DPH) algorithm, we demonstrate an efficient reconstruction of Bessel beams with arbitrary on-axis intensity. Also, the off-axis DPH method enables more than doubled laser energy utilization compared with the widely-used off-axis phase wrapping modulation method. The DPH algorithm is also used in two-photon polymerization to enable the rapid fabrication of microtube arrays, ortho-hexagonal scaffolds, and 2D patterned microstructures. This work gives experimental proof to show the powerful feasibility of the DPH method in constructing economic adaptive laser processing systems.

In the femtosecond two-photon polymerization (2PP) experimental system, optical aberrations degrade the fabrication quality. To solve this issue, a multichannel interferometric wavefront sensing technique is adopted in the adaptive laser processing system with a single phase-only spatial light modulator. 2PP fabrications using corrected high-order Bessel beams with the above solution have been conducted, and high-quality microstructure arrays of microtubes with 20 µm diameter have been rapidly manufactured. The effectiveness of the proposed scheme is demonstrated by comparing the beam intensity distributions and 2PP results before and after aberration corrections.

Femtosecond (fs) cylindrical vector beams (CVBs) have found use in many applications in recent years. However, the existing rigid generation methods seriously limit its development. Here, we propose a flexible method for generating fs-CVBs with arbitrary polarization order by employing half wave plates and vortex retarders. The polarization state, autocorrelation width, pulse width, and spectrum features of the input and generated CVB pulses are measured and compared. The results verify that the generated CVBs remain in the fs regime with no appreciable temporal distortion, and the energy conversion efficiency can reach as high as 96.5%, even for a third-order beam. As a flexible way to generate fs-CVBs, this method will have great significance for many applications.