Fabricating vector vortex waveplates for coronagraphy

Vector vortex waveplates (VVWs) have a potential of revolutionizing coronagraphy and other space imaging and communication systems. Extensive experimentation identified the role of factors that determined the properties of VVWs. Using photoalignment materials with high photosensitivity and reversible response proved key to minimizing the defect area and reducing the scattered light. Decreasing the exposure energy allowed decreasing the singularity area, and using VVWs for redistribution of light intensity from the axial regions of the beam to its periphery allowed large substrate areas to have similar exposure to the light, and production of large area VVWs. Using VVWs as linear to axial polarization converters allowed printing VVWs with higher topological charge while reducing the photoaligning time from an hour to minutes. Thus we were able to fabricate VVWs with high topological charge tuned to near infrared spectral range while keeping the singularity size to below 5 /am. Achromatic VVWs in IR spectral range were demonstrated with the aid of multilayer coating with twisted orientation.