Key words: Mechanophotonics, Flexible Organic Photonic Integrated Circuits, Organic Photonics, Non-linear Nanophotonics, Single-particle Micro-Spectroscopy
Is it possible to build photonic circuits out of molecular crystals and polymer particles?
Our research group precisely aims to achieve that using rigid/flexible crystals and dye-doped polymer particles to guide, trap, modulate, split, polarize and lase light at the microdomain - a new research field, namely, Organic Photonic Integrated Circuits (OPICs). We take an interdisciplinary approach by combining Chemistry, Physics and Materials Sciences to accomplish this goal and beyond.
To realize OPICs, our group invested more than a decade in designing, creating, micromanipulating and understanding basic photonic microcomponents viz. waveguides, resonators, modulators, lasers, as tools from custom-made molecule/polymer-based solid structures.
Our research journey towards OPICs started with discovering "Passive Organic Optical Waveguides" [Angew. Chem. Int. Ed. (2012), 51, 3556; Adv. Opt. Mater. (2013),1, 305; Adv. Mater. (2013), 25, 2963]- crystals that could guide laser light up to several microns both in linear and (naturally) bent geometries. Later, we also found a way to trap the wide band fluorescence (FL) within organic microstructures, so-called optical resonators to convert FL signal into a tunable multimodal band. Particularly, we reported the first organic chiral (R & S) resonators displaying Circular Dichroism in the non-linear optical (NLO) signal [J. Mater. Chem. C (2017), 5, 12349]. Using photo-responsive organic microcrystal passive waveguide, our group developed a unique optical experiment to modulate guided light intensity and propagation time (delay lines) using two laser beams [Adv. Opt. Mater. (2015), 3, 1035]. Production of ultra-thin organic surfaces is technologically imperative to realize potential up-conversion organic-lasers. Our group has done that by fabricating nonlinear optical microcavities, producing enhanced second harmonic generation (SHG) signal [Adv. Mater. (2017), 29, 1605260].
We reported our first successful mechanical micromanipulation operation to "lift" a crystal waveguide using an atomic force microscope (AFM) cantilever in 2014 [J. Mater. Chem. C (2014), 2, 1404]. Later, a report on mechanical "cutting" of a microcrystal cavity followed [Adv. Opt. Mater. (2016), 4, 112]. We found that unlike bulk 1D macrocrystals, the "elastic" microcrystals behave more like "plastic" on the substrate due to substrate-crystal adhesive interactions paving a way for a stable OPICs. As a result of this important finding, we invented more micromechanical operations to mechanically bent, move, split, transfer and integrate microcrystal waveguides and cavities towards OPICs- using a technique known as Mechanophotonics [Angew. Chem. Int. Ed. (2020), 59, 13821; Small (2021), 17, 2100277]. In the same year, we reported the first OPIC component - a 2x2 directional coupler made entirely from two flexible (plastic-like) organic crystals (Chemistry Views News) to split the light into two signals [Angew. Chem. Int. Ed. (2020), 59, 13852]. As a result of this innovative approach, several homo and heterocrystal OPICs possessing directional-specific and mechanism-selective [passive/active/energy transfer] photonic properties were constructed by combining chemically/electronically different crystal-waveguides and –ring resonators with very high precision [Adv. Opt. Mater, (2021), 9, 2100550; Adv. Funct. Mater. (2021), 31, 2100642].
FIB milling has been employed to machine perylene crystal resonators into different geometry and size for the first time. The fabrication of disk- and rectangular-shaped photonic resonators is a proof-of-principle experiment that can also be applied to other molecular crystals. The presented technique can be used directly to fabricate circular-, ring-, rod-shaped, and any possible geometries to create photonic modules such as resonators, waveguides, lasers, interferometers, and gratings, couplers, modulators and photonic crystals suitable for the fabrication of PICs. As the geometry and dimension of the molecular crystals can be precisely controlled down to microscale during the milling process, this technique can also be applied to the industrial-scale production of organic crystal photonic modules for PICs.
Realization of Mechanically Maneuverable Circuit Ports in Organic Hybrid Photonic Chip for 360° Steering of Bandwidth Engineered Signals"
Adv. Opt. Mater. (2022), Accepted.
Integrating Triply- and Singly-Bent Highly Flexible Crystal Optical Waveguides for Organic Photonic Circuit with a Long-Pass-Filter Effect"
Read the article in Small Structures. (2021), 3, 2100163.
Geometrically-Reconfigurable, Two Dimensional, All-Organic Photonic Integrated Circuits Made from Two Mechanically and Optically Dissimilar Crystals which functions based on active/passive/energy transfer mechanisms.
Read the article in Adv. Funct. Mater. (2021), 31, 2105415.
Micromechanical Fabrication of Resonator-Waveguides Integrated 4-Port Photonic Circuit from Flexible Organic Single-Crystals
Adv. Optical. Mater., (2021), 9, 2100550.
Mechanically Reconfigurable Organic Photonic Integrated Circuits (OPICs) - Active/Passive/ Energy Transfer Mechanisms
Adv. Funct. Mater, (2021), 31, 2100642.
Flexible Crystal-based 2 x 2 Directional Coupler
Angew. Chem. Int. Ed. (2020), 59, 13852. [Hot Article]
Mechanophotonics - Demonstration of multiple AFM manipulation operations of crystal waveguides (2020)
Angew. Chem. Int. Ed. (2020), 59, 13821-13830.
Photon Molecular Reactions & 90 deg. CROW Construction
Nanoscale Advances. (2020), 2, 5584-5590 (Hot Article)
Organic Tubular Passive Resonators (via laser-driven melting)
Phys. Chem. Chem. Phys. (2016), 18, 15528
Chiralphotonics: R & S Organic Non-Linear Optical Resonators
J. Mater. Chem. C (2017), 5, 12349-12353.
Organic Non-Linear Optical Laser
Adv. Mater. (2017), 29, 1605260.
Intensity-Modulator Implanted Organic Passive Waveguide
Adv. Opt. Mater. (2015), 3, 1035-1040
Organic Passive Organic Waveguides - Discovery
(Angew. Chem. Int. Ed. (2012), 51, 3556-3561; Adv. Opt. Mater. (2013),1, 305-311; Adv. Mater. (2013), 25, 2963; PCCP, 2014, 16, 7173-7183)