Micromanipulation of Mechanically Compliant Organic Single‐Crystal Optical Microwaveguides

Abstract

Flexible organic single crystals are evolving as new materials for optical waveguides that can be used for transfer of information in organic optoelectronic microcircuits.I ntegration in microelectronics of such crystalline waveguides requires downsizing and precise spatial control over their shape and sizea tt he microscale,h owever that currently is not possible due to difficulties with manipulation of these small, brittle objects that are prone to cracking and disintegration. Here we demonstrate that atomic force microscopy(AFM) can be used to reshape,r esizea nd relocate single-crystal microwaveguides in order to attain spatial control over their light output. Using an AFM cantilever tip,m echanically compliant acicular microcrystals of three N-benzylideneanilines were bent to an arbitrary angle,s liced out from ab undle into individual crystals,cut into shorter crystals of arbitrary length, and moved across and aboveasolid surface.W hen excited by using laser light, such bent microcrystals act as active optical microwaveguides that transduce their fluorescence,w ith the total intensity of transduced light being dependent on the optical path length. This micromanipulation of the crystal waveguides using AFM is non-invasive,a nd after bending their emissive spectral output remains unaltered. The approach reported here effectively overcomes the difficulties that are commonly encountered with reshaping and positioning of small delicate objects (the "thick fingers" problem), and can be applied to mechanically reconfigure organic optical waveguides in order to attain spatial control over their output in two and three dimensions in optical microcircuits.

An Optical Waveguiding Organic Crystal with Phase-Dependent Elasticity and Thermoplasticity over Wide Temperature Ranges

“…10 In 2012, Reddy and coworkers reported a kind of organic co-crystal that exhibited elastic bending ability under applied stress. 11 Subsequently, elastic and plastic organic crystals have been rapidly developed and deeply studied by Desiraju 12,13 , Naumov [14][15][16] , Reddy 17.18 , Hayashi 19,20 , Chandrasekar 21, 22 and our group [23][24][25][26][27][28] Notably, flexible organic crystals compatible with optical and electrical functions have been reported recently, which advanced the application of these flexible materials in optoelectronics. [29][30][31] There are two key limiting factors in expanding the application of flexible organic crystals: single mechanical property and narrow applicable temperature range.…”

Mechanophotonics: Flexible Single‐Crystal Organic Waveguides and Circuits

“…[9] Theu se of flexible-crystal waveguides in photonic microcircuits is limited by the lack of suitable manipulation techniques to deform microcrystals into intricate shapes. Furthermore,the implementation of mechanical operation in microcrystals is rather tricky due to their soft and fragile nature.M icromanipulation with atomic-force-microscopy (AFM) cantilever tips has turned out to be ap romising technique [11] to mechanically shape microcrystals without causing damage to them.…”

Optical waveguides based on one-dimensional organic crystals

“…Thus, the investigation of elastic organic crystals is one of the currently developing trends in flexible photonics. Elastic organic crystals under the external stimuli usually have various outstanding mechanical behaviors, e.g., bending [37,38,[82][83][84][85] and twisting [86,87]. As a pioneer work, Prof. Zhang et al firstly demonstrated the flexible microrods of (E)-1-(4-(dimethylamino)phenyl)iminomethyl-2-hydroxyl-naphthalene (DPIN) crystals (Fig.…”