High-Dielectric 3-D Printable Materials for Laser Accelerators

"Logpile" photonic band gap structures are an attractive option for the construction of laser dielectric accelerators. In principle, these structures can be fabricated using a commercial Nanoscribe 3-D printer, although currently available resins do not meet the materials requirements necessary for a functional dielectric waveguide for laser accelerators. In particular, the requisite optical-frequency dielectric constant is well outside the range of conventional organic materials. This work examines material options for overcoming this barrier, while simultaneously meeting requirements for loss tangent, laser-induced breakdown, and compatibility with two-photon polymerization. We present computational screening of more exotic organics resins, and synthetic options for promising candidates. In addition, we discuss materials approaches involving metal-polymer complexes, as well as germanium and metal-chalcogenide polymer nanocomposites. Prospects, inherent limitations, and initial characterization of these various materials will be discussed in the context of 3D-printed dielectric accelerators.