Research Projects

Silicon (refractive index=3.47) and silicon-based materials are exploited for the fabrication of optical interferometers useful for signal processing in photonic circuits. Optical interferometers process signals via the interference of superimposed optical waves. These interferometers are essential for advancing light-based technologies like spectroscopy, sensing, quantum computing, communication, and photonic integrated circuits. Organic crystalline materials are emerging as an alternative material platform for silicon-based photonic integrated circuits and devices. The ratio of the refractive indices of organic crystalline materials on silica is typically about 1.66/1.5, which is suitable to effectively confine optical signal for photonic applications. Further, the high exciton binding energy, exciton-polariton formation, tunable optical bandgap, linear and non-linear optical functionalities, lightweight, solution/vapor phase processability and mechanical flexibility make organic crystalline materials very attractive for photonic applications. Two important traits for flexible photonic materials are mechanical compliance and the ability to transduce light under mechanical stress. Flexible crystal waveguides have been at the center of innovation due to their potential applications in photonic circuit construction. When the substrate-crystal attractive interaction is greater than shape regaining force, elastic microcrystal's display pseudo-plasticity in extreme bent geometry. The discovery of pseudo-plasticity in my lab enabled the fabrication of many proof-of-principle organic PICs on silica substrate by manipulating optical microcrystal geometries using atomic force microscopy (AFM) tip - an approach known as mechanophotonics. This proposal focuses on utilizing organic microcrystal waveguides to construct custom-designed optical interferometers via mechanophotonics approach. We will use high quantum yield molecular materials with various optical bandwidths such as perylene, pentacene, 9,10-bis(2-phenylethynyl)anthracene, and 4-nitro-N,N-dimethylaniline will be used to obtained required microcrystals through solvent-assisted self-assembly or evaporation of mother liquor during crystal growth. We will investigate the photonic response of interferometers using custom-made confocal optical microscope coupled to different lasers (355, 405, 488, 633 and 785 nm). The optical response can be comprehensively understood using finite difference time domain calculations. Additionally, developing organic interferometers for photonic applications requires designing, fabricating, and testing diverse optical components with complex functional attributes and understanding the various mechanisms through which they operate. We plan to fabricate interferometers such as Sagnac-type, Hybrid-type, Spiral Waveguide-type, and Reck-type. More, importantly, as this is an original idea, the outcome of the project will ascertain India's presence internationally.