Mechanically robust amino acid crystals as fiber-optic transducers and wide bandpass filters for optical communication in the near-infrared

Abstract

Organic crystals are emerging as mechanically compliant, light-weight and chemically versatile alternatives to the commonly used silica and polymer waveguides. However, the previously reported organic crystals were shown to be able to transmit visible light, whereas actual implementation in telecommunication devices requires transparency in the near-infrared spectral range. Here we demonstrate that single crystals of the amino acid L-threonine could be used as optical waveguides and filters with high mechanical and thermal robustness for transduction of signals in the telecommunications range. On their (00$$\bar 1$$ 1 ¯ ) face, crystals of this material have an extraordinarily high Young’s modulus (40.95 ± 1.03 GPa) and hardness (1.98 ± 0.11 GPa) for an organic crystal. First-principles density functional theory calculations, used in conjunction with analysis of the energy frameworks to correlate the structure with the anisotropy in the Young’s modulus, showed that the high stiffness arises as a consequence of the strong charge-assisted hydrogen bonds between the zwitterions. The crystals have low optical loss in the O, E, S and C bands of the spectrum (1250−1600 nm), while they effectively block infrared light below 1200 nm. This property favors these and possibly other related organic crystals as all-organic fiber-optic waveguides and filters for transduction of information.

Elastic Organic Crystals Based on Barbituric Derivative: Multi‐faceted Bending and Flexible Optical Waveguide

“…The above phenomenon showed that the crystal had the nature of multi-faceted bending and exhibited good mechanical properties, which had the potential application in fiber-optic transducers, mechanical deformation-induced discoloration materials, waveguiding biomaterials, artificial muscles, etc. [42][43][44][45] In order to further study the surface morphology and face index of the crystal, we selected a crystal and conducted a SEM test. As shown in Figure S3, the crystal surface had defects and was not completely smooth.…”

Multifunctional Deformable Organic Semiconductor Single Crystals

“…Typically, optical waveguide properties of organic crystals focus on the visible light region, while very limited information exists in the near‐infrared [54, 55] . Therefore, the optical waveguiding properties of form A and B crystals of BPEA were assessed in the O band (1260–1360 nm) and the C band (1530–1565 nm) by coupling a single crystal with a near‐infrared input light from tunable laser sources.…”

“…To our knowledge, organic semiconducting crystals have not been explored yet as multifunctional devices with broadband photodetection (visible and near‐infrared) and optical transduction in the near‐infrared region. However, photodetecting capability and optical transduction performance in the telecommunications (datacom) range (1250–1600 nm) is germane to the development of multifunctional optoelectronic single crystal devices [55] . Our own investigation of this material showed that crystals of the two phases have diametrically different mechanical properties; while crystals of form A are elastic at room temperature, crystals of form B are brittle but become plastic at high temperature.…”

Low-Power Laser Micro-Shaping of Dye-Volatile Cocrystals: The Gentle Cutting Edge of Photoresponsive Materials

“…Similar to the dioxanebased system, (trans-azo)(pyrazine) showed a differential response to irradiation by different laser power (Supplementary Figs. [33][34][35]. Irradiating a crystal of ~15 μm thickness at 5 mW for 40 ms produced no response, while irradiating with a pulse of the same length but at a power of 15 mW led to fog emission.…”

“…isomerization, 22,23 dimerization, 24,25 or polymerization 26,27 ); photomechanical motion, 21,[28][29][30] photochromism, 31 and waveguide behaviour. 32,33 While traditional photolithography has been applied to polymeric resins, 34 hyperbolic metamaterials, 35 nanostructures, 36 photonic crystals 37 and cocrystal thin films, 38 the ability to accurately shape, or machine, organic crystalline solids using low-powered visible or ultraviolet (UV) light has yet to be achieved. While machining of patterns has been reported using high-energy beam techniques, such as focused ion beam (FIB) milling, 39 electron beam lithography, or femtosecond laser beam machining, 40 these methods operate at high energies (1-50 keV) and beam powers (on the order of several Watts) that produce chemical damage to organic materials, and are most commonly used for organic polymers and inorganic materials.…”