Achromatic Vector Vortex Waveplates for Coronagraphy

Using small aperture telescopes for detecting exoplanets could have a significant impact on astronomy and other imaging and space communication systems. In this new generation of smaller, lighter and more affordable coronagraph systems, the starlight is rejected with the aid of phase-based transparent masks capable of transmitting planetary light at small angular separation from the star. These so-called vector vortex waveplates (VVW) are complex optical components wherein the optical axis orientation is azimuthally modulated in space at a high spatial frequency. In the Phase 1 of the project, we showed the feasibility of fabricating VVWs that would meet requirements for astronomy applications due to small singularity size, high topological charge, high contrast, and broadband functionality. The breakthrough polarization conversion and beam shaping technology of printing VVWs developed in the Phase 1 will undergo further fundamental improvements in the Phase 2 of the project along with further optimization of photoalignment materials and liquid crystal polymers to fabricate and deliver VVWs characterized by: subwavelength singularity sizes; spectrally broadband/achromatic functionality, particularly, for infrared wavelengths; stability to radiation and large temperature variations; and functionality at cryogenic temperatures. This will accomplish the project's general objective – development and delivery of VVWs adequate for practical use.