Mechanophotonics: fabrication of a 2 × 2 hybrid directional coupler from flexible organic crystals

Abstract

Microcrystalline organic optical components are crucial to construct miniature devices. However, the design and fabrication of such organic photonic components with multifunctional capabilities remains a challenging enterprise. Herein, we report the synthesis of a mechanically flexible blue-emissive (Z)-3-(3′,5′-bis(trifluoromethyl)-[1,1′-biphenyl]-4-yl)-2-(4-methoxyphenyl)acrylonitrile (CF₃OMe) crystal waveguide. The exceptional mechanophotonic properties exhibited by the CF₃OMe crystals manifest their suitability for photonic circuits. The integration of a CF₃OMe microcrystal waveguide with a green-emissive BPyIN microcrystal waveguide via the mechanophotonics technique allows the creation of an innovative hybrid 2 × 2 directional coupler (HDC) with four terminals. The HDC functions as an optical signal splitter and signal chromaticity modulator when CF₃OMe crystal receives the input signal. The same device becomes only a signal splitter for light input at the BPyIN crystal. Thereby, a novel HDC performing multiple functions, viz., splitting, chromaticity modulation, and directed delivery of optical signals, was realized. The demonstration of such innovative circuits corroborates the versatility of organic crystal photonics for devising technologically relevant organic photonic integrated circuits.