Crystal photonics foundry: geometrical shaping of molecular single crystals into next generation optical cavities

The advancements in organic photonics have reached new heights in the recent past with the demonstration of diverse organic crystal optical components and circuits. However, the development of industrially viable manufacturing of organic optical components is the need of the hour for finding an alternative to silicon-based photonics. Here, we demonstrate focused ion beam (FIB) milling as a tool to shape organic single crystals into optical cavities of diverse geometries and dimensions. The generality of FIB milling was tested on perylene and coumarin-153 microcrystals. The microcrystals obtained by self-assembly of perylene and sublimation of coumarin-153 were carved into desired disc-, ring- and rectangular shapes. These shaped crystals act as cavities exhibiting sharp resonance modes in the fluorescence spectrum, confirming optical interference. The FDTD numerical calculations support the light electric field distribution in these optical cavities. This unprecedented single crystal processing technique enables industrial-scale production of optical components and circuits and acts as a foundry for crystal photonics.