Two-photon polymerization with optimized spatial light modulator

Abstract

The application of diffractive optical elements can enhance the efficiency of the two-photon polymerization (TPP) process by multiplying the polymerizing beams. Spatial light modulators (SLMs) can dynamically change the light intensity pattern used for polymerization, making single shot polymerization possible. Most reflective, liquid crystal-based instruments, however, suffer from various surface aberrations. In order to enable SLMs to generate suitable polymerizing beams for TPP, these aberrations need to be corrected. Several methods were introduced earlier to compensate SLM aberrations in different applications. For the nonlinear process of TPP, we developed and specifically characterized a correction procedure. We used a simple interferometric method to determine the surface distortion of the SLM, calculated a correcting hologram and confirmed the correction with the polymerization of test structures. The corrected SLM was capable of parallel polymerization of 3D structures with a quality achievable with non-SLM beams.

Keywords

• diffractive optics
• 3d microstructure fabrication
• spatial light modulators
• laser materials processing