One-Dimensional Programmable Polymeric Microfiber Waveguide

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Applications of Polymer, Composite, and Coating Materials

One-Dimensional Programmable Polymeric Microfiber Waveguide with Optically Recon#gurable Photonic Functions Hongyan Xia, Junjie Cheng, Liangfu Zhu, Kang Xie, Qijin Zhang, Douguo Zhang, and Gang Zou ACS Appl. Mater. Interfaces, Just Accepted Manuscript • DOI: 10.1021/acsami.8b22140 • Publication Date (Web): 09 Apr 2019 Downloaded from http://pubs.acs.org on April 9, 2019

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ACS Applied Materials & Interfaces

One-Dimensional Microfiber

Programmable

Waveguide

Polymeric

with

Optically

Reconfigurable Photonic Functions Hongyan Xia, †,‡,# Junjie Cheng, †,# Liangfu Zhu, § Kang Xie, ‡ Qijin Zhang, † Douguo Zhang, §,* and Gang Zou†,*

†

CAS Key Laboratory of Soft Matter Chemistry, Department of Polymer Science and

Engineering, iChEM, University of Science and Technology of China, Hefei, Anhui 230026, P. R. China ‡Dongyuan

Synergy Innovation Institute for Modern Industries of GDUT, Guangdong University

of Technology, Guangzhou 510006, P.R. China §

Department of Optics and Optical Engineering, University of Science and Technology of

China, Hefei, Anhui 230026, P. R. China #These

authors contributed equally to this work.

KEYWORDS:

single

polymeric

waveguide,

dynamic

fluorescence,

fluorescence

heterojunctions, reconfigurable photonic components, programmable functions.

ACS Paragon Plus Environment

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ABSTRACT: Programmable materials and reconfigurable photonic components, which can change their physicochemical properties and functionalities upon external stimuli, are a major topic of interest in modern science. However, most conventional reconfigurable photonic components rely heavily on mechanical deformation, restricting their application. Herein, a novel strategy based on dynamic tunable fluorescence resonance energy transfer (FRET) process to design and fabricate programmable fluorescent micro-patterns within single polymer microfiber is proposed. A set of reconfigurable photonic components (including optical switchable waveguide systems, photonic analogies of diodes and transistors, as well as one-dimensional optical encoding) can be achieved within a single polymeric waveguide microfiber straightforwardly, in which such photonic components can be written, erased and rewritten as one-dimensional (1D) binary patterns with tailored external optical stimuli. These results might be of great fundamental value for the rational design of novel reconfigurable photonic devices with numerous potential applications in highly integrated optical communication components and optical computing devices.

INTRODUCTION 1D optical micro/nanofibers have been extensively used as the building blocks in the field of micro- or nano-optical waveguide systems and photonic devices since they can confine and manipulate optical signals at micro- or nanoscale, offering a prospective strategy to break the energy consumption and speed limitation in circuits. It is well known that the out-coupled signals of 1D optical waveguide strongly depended on the material compositions and structural parameters. Thus far various functional materials including inorganic semiconductors,1 organic


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assemblies,2-4 dye-doped polymers and conjugated polymers,5-6 had been utilized to construct 1D optical waveguides with diverse photonic functions, such as light modulators,7 logic gates,8 photonic analogies of diodes and transistors.9-14 While the photons could be subtly confined and transported with tunable parameters such as intensity, wavelength, polarization and so on. However, it is still challenging to achieve multi-functional photonic components highly integrated in a single micrometer-sized 1D optical waveguide system for future applications in highly integrated photonic devices and chips towards optical information processing, especially reconfigurable photonic components with programmable heterojunctions. Recently, extensive studies mainly focus on the controlled synthesis of programmable materials with specific nanostructures and composite distributions, whose tunable photonic properties make them suitable for serving as attractive photonic elements for the next-generation optical computing platforms.15 It is anticipated that the combination of advances in the field of micro-fabrication technique and programmable materials will produce novel reconfigurable photonic components with tunable parameters, offering synergistically enhanced performances and functionalities for future applications in highly integrated photonic devices.16 However, most conventional reconfigurable photonic components rely heavily on mechanical deformation,17 and can only be realized restrictedly by either micro- or nanomechanical actuation,18 stretching,19-21 or heating,22 limiting their application in micro- or nanoscale photonic devices. While some other superior reversibility photochromic materials,23-25 which are ideal candidates for programmable functional components, have not been exploited to develop complicated photonic functions except fundamental optical waveguide. Herein, reconfigurable photonic components within a single polymeric fiber waveguide system utilizing the photo-responsive spiropyran-fluorescein hybrid materials based on dynamic


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tunable FRET process was demonstrated. The programmable micro-patterns could be written, erased and rewritten easily on a single polymeric fiber media by combination with laser direct writing (LDW),26-27 or digital micro-mirror device (DMD) technique,28 which gives the possibility for the dynamic control and manipulation of microstructural parameters and optical signals across the single microfiber to achieve various photonic functions. By taking advantage of the structure of 1D polymeric microfiber waveguide, optically reconfigurable photonic components with programmable functions including optical switchable waveguide systems, photonic analogies of diodes and transistors, as well as 1D optical encoding have been realized successfully. It is anticipated that this optically reconfigurable photonic platform will shed new light on the development of programmable photonic devices for future photonic integrations.

EXPERIMENTAL SECTION Materials: 1-(2-Hydroxyethyl)-3,3-dimethylindolino-6'-nitrobenzopyrylospiran (spiropyran) was purchased from Tokyo Chemical Industry Co. Ltd., 5(6)-carboxyfluorescein (fluorescein, CF) and poly(styrene) (PS, Mw = 26w) were obtained from Aladdin Chemistry Co. Ltd. (Shanghai, China) and J&K Chemical Co. Ltd. respectively. All the reagents and solvents were of analytical grade and used as received without any further purification. Preparation of chameleon-like fluorescent polymeric microfiber waveguides with programmable micro-patterns: Chameleon-like fluorescent polymer microfiber was fabricated preliminarily through a typical electrospinning procedure on a commercial electrospinning equipment (Figure S1). Namely, 6.0 mg spiropyran and 0.6 g PS were dissolved in 1.5 mL chloroform, then a 0.5 mL ethanol solution containing 2.8 mg fluorescein was injected fleetly. The mixture was stirred at room temperature for at least 3 hours to guarantee dyes could be


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dissolved utterly. The as-prepared solution was stocked in a 2 mL disposable syringe afterwards. A 0.5 mm internal diameter stainless steel needle with flat tip was employed as spinneret, and a 10 kV positive potential was applied from the high voltage power supply, while a 2 kV negative potential was utilized to another electrode simultaneously. The distance between two counter electrodes was 10-25 cm in accordance with the actual circumstances, whilst the feed rate was sustained to 0.2 mm∙min−1 with the syringe pump. The fibers were collected at a distance of 10 cm from the tip of the spinneret and transferred to ultrathin transparent glass substrates hereafter. Programmable micro-patterns within above single polymer microfiber could be created by optical lithography technique, which was carried on a home-built imaging system utilizing LDW or DMD technique. The detailed experimental setup for patterning could be found in Supporting Information (Figure S2 and Movie S1). In brief, a specific pattern designed previously was transferred to microfiber by exposed to an intense light field produced by LDW or DMD, and the local PL properties and heterostructures within 1D polymeric optical waveguides could be easily adjusted by irradiated with UV (254-365 nm) and visible light (450-600 nm) based on the dynamic tunable FRET process between fluorescein and spiropyran in the merocyanine (MC) form within PS matrix. Characterization: Scanning electron microscopy (SEM) was carried on an FEI Sirion200 system. Ultraviolet-visible (UV-Vis) absorption spectra were measured by using a SHIMADZU UV-2550 PC spectrophotometer. Photoluminescence (PL) spectra were obtained from an RF5301 PC spectrophotometer. Raman scattering spectra were measured with a JY-ihR 550 spectrometer established on an IX-71 (Olympus) microscope. The fluorescence lifetime characterizations were performed on FluoroHub and analyzed with DataStation (HORIBA Jobin Yvon). PL image and out-coupled spectra within 1D polymeric microfiber optical waveguides


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were characterized on a home-built optical system (Figure S2).

RESULTS AND DISCUSSION To achieve programmable polymeric microfiber waveguide with reconfigurable photonic functions, there are several prerequisites: (i) dynamic fluorescence and waveguide properties that can be finely tuned by external stimuli; (ii) outstanding reversibility and stability; (iii) programmable waveguide structure and various photonic functions. The fluorescence and waveguide properties of the polymer microfibers, including out-coupled emission intensity and color, could be modulated by varying the irradiation wavelength, position and time basing on the efficient FRET process between spiropyran and fluorescein within poly(styrene) (PS) matrix dynamically. Moreover, programmable micro-patterns within a single polymeric fiber waveguide system could be written, erased and rewritten simply by LDW or DMD technique, which allows the dynamic control and manipulation of microstructural parameters and optical signals across the single polymer microfiber to achieve complicated photonic functions, as shown in Figure 1, including optical switchable waveguide, photonic analogies of diodes and transistors, and 1D optical encoding. Optically reconfigurable polymeric microfiber waveguide with color-tunable emission. Manipulation of optical signals in polymeric microfiber waveguide plays a critical role in the development of new photonic devices and systems.3 Although there are extensive studies on the waveguide properties of 1D active polymer materials, the flow of light in polymer microfiber is predetermined and cannot be readily reversibly modulated subsequently, limiting their practical application in optical communication components and integrated optoelectronic devices. Hence, it remains challenging to develop novel 1D polymer waveguide with tunable performance,


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especially out-coupled color-switchable emission. Here, 1D spiropyran and fluorescein embedded PS microfiber was fabricated by a typical electrospinning procedure and the prepared hybrid polymer microfiber had an average diameter of about 2 m with smooth and beads-free nature (Figure S1). The optical waveguide of above microfiber was studied by the single-tube photoluminescence (PL) imaging method via local excitation of the microfiber with a focused 488-nm-wavelength incident laser beam (solid-state lasers), while overall sketch was acquired via global illuminated with a diffused laser and presented incidentally. The distal tip of the as-prepared microfiber emitted bright green PL (Figure 2a, left, bottom) centered at 525 nm (Figure 2b, green line), while a comparatively weaker PL emission could be observed from the body of the hybrid polymer microfiber. The waveguided green light within the above hybrid microfiber was attributed to the inherent PL property of the embedded fluorescein. While upon exposure to 325 nm (Helium-Cadmium Lasers, He-Cd Lasers) radiation for 3 s (Figure S3, long treatment time to ensure isomerization completely), the whole hybrid polymer microfiber turned red (Figure 2a, right, upper) and the distal tip of microfiber emitted bright red PL (Figure 2a, right, bottom) centered at 635 nm (Figure 2b, red line), and the fluorescence lifetime of the hybrid microfiber varied from 0.65 ns to 3.65 ns (Figure 2c),29-30 which should be ascribed to structural transformations from the colorless ring-closed spirocyclic (SP) form to the strongly colored ring-opened merocyanine (MC) form, consistent with the results of Raman (Figure S4),31-32 and ultraviolet-visible (UVVis) absorption spectra (Figure S5). In this case, FRET between the MC form of spiropyran and fluorescein would occur since the absorption band of the MC form of spiropyran overlap with the emission band of fluorescein exactly (Figure S6). After irradiated with 442 nm light (He-Cd Lasers) for 10 s, the MC form of spiropyran transferred back to the SP form, the whole


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microfiber turned back to green while the tip emission returned back to its original values, almost the same as that before 325 nm treatment. It should be noted here that above optical modulation of waveguide with color tunable tip emission in the hybrid polymer microfiber exhibited excellent stability and reversibility. While even after 50 more regeneration cycles, the tip emission of the microfiber exhibited similar PL changes without loss of sensitivity (Figure S7). Nevertheless, the switching speed was a little slower for their potential application in photonic circuit although the photo-isomerization of spiropyran could be ultrafast (ring-open, 1.6 ps; ringclose, 257 nm could be calculated. So theoretically, the fiber (PS matrix) with a diameter less than 257 nm could not


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effectively propagate the light towards the distal tips. Conclusively, the reversible optical modulation of waveguide with color tunable tip emission in above hybrid polymer microfiber could be realized based on the dynamically tunable FRET process between spiropyran and fluorescein within PS matrix. The controllable switching of guided light in 1D polymeric microfiber waveguide may pave the way for rational design of smart polymer photonic devices. Two-block heterojunctions with asymmetric light propagating behavior. In the past decades, structures that allow unidirectional propagation of electrical current have attracted enormous attention since they represent key building blocks for the electronic devices and circuits. Similarly, extensive studies are focused on the study of asymmetric light propagating, 3537which

might find potential application in all-photonic computing, processing and integrations.

However, it is still challenging to achieve asymmetric light propagation in polymeric microfiber active waveguide owing to the difficulty in finely control of the spatial exciton emission along the path of light propagation. Here, the design and realization of asymmetric light propagation in single composition-graded polymeric microfiber waveguide was reported. The color and intensity of the guided light within the microfiber were highly dependent on the propagation direction as a result of the existence of the intrinsic spatially-graded composition and the difference of FRET efficiency along its axial direction, which provided the physical base of the asymmetric light propagation. To realize above conception, polymeric microfiber waveguide heterojunctions were prepared utilizing LDW technique precisely. In this case, half part of polymer microfiber was irradiated with 325 nm light for 3 s and subsequently turned red owing to the structural transformations of spiropyran from SP form to MC state, while the other part of polymer


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microfiber kept green without irradiation. The contents of spiropyran in MC form within the microfiber matrix were gradually changed along its length, as confirmed by the position dependent micro-Raman characterization (Figure S9). Therefore, the efficiency of the FRET process was also gradually changed along the polymer microfiber, as suggested by the position dependent fluorescence lifetime characterizations (Figure S10). Upon the illumination of a 488nm-wavelength diffused laser, the exhibited PL color of the microfiber was continuously varied from green to red along its entire length (Figure 3a, upper), with the PL wavelength spanning from 525 nm to 635 nm (Figure S11). Figure 3a (middle and bottom) gave the real color PL microscopic images of the microfiber excited with the focused laser at its two distal ends respectively. The excitation power density was kept the same, while different PL signals could be detected at the two opposite output ends. As shown in Figure 3b, the backward output end emitted bright orange PL with two peaks centered at 525 nm and 635 nm, whereas only red PL centered at 635 nm could be detected at the forward output end. In the case of backward propagation for the excitation position, green PL (525 nm) of fluorescein were excited and propagated. Partial propagated green PL was converted to red owing to the efficient FRET process between fluorescein and spiropyran in the MC form. Therefore, orange PL with two peaks centered at 525 nm and 635 nm could be detected from the distal end. However, in the case of forward propagation, only red PL (635 nm) could be excited and propagated to the distal end. This observation plainly indicated that the propagation behavior along the two opposite directions are utterly different, which should be ascribed to the heterojunction microstructure difference along the path of light propagation. To further evolution the asymmetric light propagation along two opposite directions, the microfiber was locally excited by a focused laser (488 nm) and the output PL signals from its


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both ends were detected simultaneously. As shown in Figure 3c, when the excitation spot was located in the green part of the microfiber, as expected, merely green PL of fluorescein was generated at the excitation position, while the forward and backward output ends exhibited different PL signals. In the case of forward propagation, partial propagated green PL was converted to red PL owing to the efficient FRET process during light propagating process. Therefore, orange PL with two peaks centered at 525 nm and 635 nm was detected from the distal end. Whereas in the case of backward propagation, no efficient FRET occurred, only green PL be detected from the distal end. We must note here that when the excitation spot was located in the red part of the microfiber, as shown in Figure 3d, only red PL (635 nm) of spiropyran in the MC form generated at the excitation position. The forward and backward output ends emitted similar red PL (635 nm), but different intensity. All above results further confirmed that these polymeric microfiber waveguide heterojunctions exhibited large difference in the output PL signals during light propagation and provided the working principle for the hybrid microfiber-based asymmetric waveguides. Three-block heterojunctions analogies of photonic transistors. Electronic transistor, a ubiquitous semiconductor device used to amplify or switch electronic signals and electrical power, is the fundamental building block of modern electronic circuits. While the bipolar junction transistor (BJT), as a conventional type of the transistors, comprising three differently doped semiconductor regions which could be theoretically simplified as two p-n junctions shared a thin n- or p-doped region. As mentioned above, the asymmetrical waveguide of PL signals, analogizing the photonic diodes, could be realized in single polymeric microfiber waveguide based on the dynamic tunable FRET process. Inspired by the structure of conventional electronic BJTs, color-graded structure (green-red-green 3-blocks) within a single polymer microfiber was


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fabricated by the application of LDW technique to realize analogical photonic transistor function. The experiment results showed that by applying a He-Cd Lasers (325nm/442nm) as the base modulator, the output light signals could be continuously altered with good reliability. 325 nm irradiation on the middle part of as-prepared fiber will induce the isomerization of spiropyran to the MC form, which can generate red PL signal in the final out-coupling owing to the efficient FRET process. As shown in Figure 4a, a consistent focused 488-nm-wavelength laser was adopted to activate above single polymeric microfiber waveguide, while another He-Cd Laser (325nm or 442 nm) was applied to the middle part of the microfiber to manipulate the waveguide light signals as the base modulator. The output light signals quantified by green (525 nm)/red (635 nm) ratio can represent ON/OFF states in this analogy of photonic transistors. Obviously, the “base” laser focused at the middle part was utilized to open the photonic transistor by altering the wavelength from 442 nm (ON state) to 325 nm (OFF state). Accordingly, as indicated in Figure 4d, the green/red ratio of the output signal at the right distal tip varied from 4.2 (ON) to 2.5 (OFF). By altering the wavelength from 325 nm to 442 nm, the close operation could be performed in the same microfiber and the green/red ratio of the output signal at the distal tip return back to 4.2. The green/red ratio of the output signal at the distal tip remained almost unchanged even after hundreds of times of open/close operations. All above results confirmed that the complexed photonic heterojunctions within single polymer microfiber could be constructed by application of LDW technique, to realize analogies of photonic transistor function with good stability and reliability. In future work, by optimizing the waveguide design, the response of these photonic components and the contrast of different states could be further improved significantly.


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Multi-block heterojunctions with programmable encoding/decoding function. Barcodes have been commonly used to product identification and information encoding in our daily life. Herein, we designed and fabricated multi-block heterojunctions using above polymer microfiber, which could be applied as the luminescent encoding/decoding carrier in effective readout method by analyzing output signal. By the application of DMD technique, the encoding patterns are created easily on the polymer microfiber based on the dynamically tunable FRET process (Figure 5a). Upon 325 nm irradiation, the structural transformations of spiropyran from the SP form to the MC form occurred in the irradiated area and the emission in these segments turn red immediately. However, in the unirradiation area, spiropyran kept in the SP form and the emission in these segments maintained green unchanged. Single polymer microfiber composed of alternative red and green emission segments could be observed from the real-color PL microscopic images shown in Figure 5b, confirming that the encoding patterns have been successfully written onto the polymeric microfiber upon 325 nm irradiation combined with DMD technique. We defined the red emission segment as “0” and the green emission segment as “1”. As mentioned above, the light propagation was very sensitive to the heterojunctions, therefore the output signal (quantified by green/red ratio) can be employed to decode the written encoded information on the microfiber. When excited with a focused laser (488 nm) at the left tip, a completely different set of encoding information could be read out straightforwardly. Obviously, the red emission segment nearby the out-coupled tip would promote the emission ratio at 635 nm, while the green part nearby the out-coupled tip would suppress the emission ratio at 635 nm. Thus, we can analyze the encoded information by analyzing the out-coupled emission ratio (Figure S12, Figure 5c). It should be noted here that above programmable multi-blocks fluorescence pattern within hybrid polymer microfiber could be easily erased and their


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corresponding encoding/decoding function could be reset simply by 442 nm irradiation. Inspired by ASCII (American Standard Code for Information Interchange), a commonly used character-encoding schemes with 8-bit byte for electronic communication, heterojunction pairs (4-blocks, 2 fiber, 8 bits, 1 byte) were encoding and recoding successively to record and transfer message straightforwardly. A character, capital letter U for instance, was converted to ASCII code 0101 0101 initially and wrote into the polymer microfiber by the 325 nm irradiation with programmable DMD technique directly. On alternating irradiation with programmable 442 nm and 325 nm light, polymer microfiber with different programmable encoded fluorescence pattern corresponding to S (0101 0011), T (0101 0100), C (0100 0011), could be observed sequentially (Figure 5d). As expected, the out-coupled tip emitted a series of different according PL signal, through which the written coded information could be read out easily. In this sense, by using programmable 325 nm irradiation as the encryption key, the polymeric microfiber waveguide exhibited interesting encoding/decoding functions through analyzing the defined outcoupled emission ratio. We anticipated that, in the future, multi-colored segments could be generated by changing the chemical composition and fluorescence dyes within the hybrid polymer microfiber, and the complicated photonic signal logics and encoding/decoding on single polymeric microfiber waveguide will be achieved.

CONCLUSIONS In conclusion, we demonstrated a feasible and economical strategy for fabricating programmable fluorescent micro-patterns within the single polymer microfiber based on dynamically photo-responsive FRET process. A series of programmable fluorescence heterojunctions within the single polymeric microfiber waveguide system could be written,


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erased and rewritten easily by application of LDW or DMD technique. As expected, a set of reconfigurable photonic components including optical switchable waveguide systems, photonic analogies of diodes and transistors, as well as encoding/decoding on single polymeric microfiber waveguide systems have been realized. The convenient preparation, excellent stability and reversibility of the microfiber enhance the utility of this micro-fabrication method basing on dynamic fluorescent materials when applied to obtain reconfigurable photonic components and develop novel programmable photonic functions.

FIGURES:

Figure 1. Schematic mechanism and functions of the programmable polymeric microfiber optical waveguide. Basing on the dynamic tunable FRET process between spiropyran and fluorescein (middle), photonic components with programmable functions have been realized successfully, including optical switchable waveguide systems (upper-left), photonic analogies of diodes (upper-right) and transistors (bottom-right), and 1D optical encoding (bottom-left).


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Middle: 325 nm laser ON, SP →MC, FRET ON, red PL emission; 442 nm laser ON, MC →SP, FRET OFF, green PL emission.

Figure 2. Reconfigurable microfiber waveguide with color-switchable emission. a) Real-color PL microscopic images of the same single hybrid polymer microfiber before (green, left) and after (red, right) 325 nm irradiation. Upper: overall sketch, diffused laser global illumination; Bottom: optical waveguide, focused laser local excitation. PL spectra b) and c) PL decays before (green) and after (red) 325 nm irradiation.


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Figure 3. Microfiber waveguide heterojunction with asymmetric light propagation. a) Real-color PL microscopic images of the same single two-block heterojunctions illuminated with a diffused laser (overall sketch, upper), locally excited at its left red distal end with a focused laser (optical waveguide, middle), and locally excited at its right green distal end with a focused laser (optical waveguide, bottom). b) PL spectra of the forward (green) and backward (red) waveguide collected from the other distal end corresponding to the middle and bottom in a) respectively. c), d) PL spectra of the forward (green) and backward (red) waveguide when the excitation spot was located in the green and red part of the microfiber respectively. Insert: schematic diagrams of excitation position (overall sketch, bottom), forward and backward waveguide (optical waveguide, upper).


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Figure 4. Photonic analogies of transistors within a single microfiber. a) Schematic illustration for the design of the photonic transistors, including the Emitter laser (488 nm laser), Base modulator (325/442 nm laser, LDW) and Collector detector (objective lens). b) The symbol of the analogized bipolar transistor (PNP type). Three terminals are labeled as Emitter, Base and Collector respectively. c) Real-color PL microscopic images of the heterojunctions analogies of photonic transistor operated between OFF and ON states by LDW. Upper-upper & bottom-upper: overall sketch, diffused laser global illumination; Upper-bottom & bottom-bottom: optical waveguide, focused laser local excitation. d) The output signal (quantified green/red ratio of the output waveguided PL spectra from the right distal tip) in two distinct OFF/ON states.


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Figure 5. Multi-block microfiber structures with programmable encoding/decoding function. a) Schematic process of encoding/decoding within the microfiber in pairs (1 byte) by DMD. b) Real-color PL microscopic images of multi-blocks structures created by DMD technique. Diffused laser global illumination, overall sketch; 3-, 4-, 5- and 6-blocks presented here. c) The quantified output signals (green/red ratio) from 4-blocks structures locally excited at distal end with a focused laser (optical waveguide). Red=0, green=1. All 16 patterns included. d) The encoded patterns and quantified output signals (optical waveguide, red/green ratio) with specific message (USTC) in ASCII encoding scheme.

ASSOCIATED CONTENT Supporting Information.


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The Supporting Information is available free of charge on the ACS Publications website at DOI: XXX. Preparation of microfibers, optical experiments set-up, spectral overlap of CF and MC, Raman spectra, UV-Vis absorption spectra, PL spectra, fluorescence lifetime and 4-blocks patterns illustration (PDF) Video displaying the patterning procedures by LDW technique (AVI) AUTHOR INFORMATION Corresponding Author *E-mail: [email protected] (D.G. Zhang). *E-mail: [email protected] (G. Zou). Author Contributions #H.Y.

Xia and J.J Cheng contributed equally to this work. All authors read the manuscript and

approved its final version. Notes The authors declare no competing financial interest. ACKNOWLEDGMENT This research was carried out with funding from the National Natural Science Foundation of China (No. 21574120, No. 21774115, No. 51803037, No. 11574070, No. 11874126), the Basic Research Fund for the Central Universities (WK2060200025), the Science and Technological Fund of Anhui Province for Outstanding Youth (1608085J01), and the funding from the Leading Talents of Guangdong Province program.


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REFERENCES (1) Li, Y. J.; Yan, Y.; Zhao, Y. S.; Yao, J. Construction of Nanowire Heterojunctions: Photonic Function-Oriented Nanoarchitectonics. Adv Mater 2016, 28, 1319-1326. (2) Zhang, C.; Yan, Y.; Zhao, Y. S.; Yao, J. From Molecular Design and Materials Construction to Organic Nanophotonic Devices. Acc Chem Res 2014, 47, 3448-3458. (3) Zhao, Y. S.; Fu, H.; Peng, A.; Ma, Y.; Liao, Q.; Yao, J. Construction and Optoelectronic Properties of Organic One-Dimensional Nanostructures. Acc Chem Res 2010, 43, 409-418. (4) Venkatakrishnarao, D.; Mohiddon, M. A.; Chandrasekhar, N.; Chandrasekar, R. Photonic Microrods Composed of Photoswitchable Molecules: Erasable Heterostructure Waveguides for Tunable Optical Modulation. Adv. Opt. Mater. 2015, 3, 1035-1040. (5) Ma, H.; Jen, A. K. Y.; Dalton, L. R. Polymer-Based Optical Waveguides: Materials, Processing, and Devices. Adv. Mater. 2002, 14, 1339-1365. (6) Garreau, A.; Duvail, J. L. Recent Advances in Optically Active Polymer-Based Nanowires and Nanotubes. Adv. Opt. Mater. 2014, 2, 1122-1140. (7) Deotare, P. B.; Bulu, I.; Frank, I. W.; Quan, Q.; Zhang, Y.; Ilic, R.; Loncar, M. All Optical Reconfiguration of Optomechanical Filters. Nat Commun 2012, 3, 846. (8) Wei, H.; Wang, Z.; Tian, X.; Kall, M.; Xu, H. Cascaded Logic Gates in Nanophotonic Plasmon Networks. Nat Commun 2011, 2, 387. (9) Fan, L.; Wang, J.; Varghese, L. T.; Shen, H.; Niu, B.; Xuan, Y.; Weiner, A. M.; Qi, M. An All-Silicon Passive Optical Diode. Science 2012, 335, 447-450. (10) Baugher, B. W. H.; Churchill, H. O. H.; Yang, Y.; Jarillo-Herrero, P. Optoelectronic Devices Based on Electrically Tunable P–N Diodes in a Monolayer Dichalcogenide. Nature Nanotechnology 2014, 9, 262-267. (11) Lee, M. Y.; Hong, J.; Lee, E. K.; Yu, H.; Kim, H.; Lee, J. U.; Lee, W.; Oh, J. H. Highly Flexible Organic Nanofiber Phototransistors Fabricated on a Textile Composite for Wearable Photosensors. Adv. Funct. Mater. 2016, 26, 1445-1453. (12) Crosnier, G.; Sanchez, D.; Bouchoule, S.; Monnier, P.; Beaudoin, G.; Sagnes, I.; Raj, R.; Raineri, F. Hybrid Indium Phosphide-on-Silicon Nanolaser Diode. Nature Photonics 2017, 11, 297-300. (13) Miller, D. A. B. Are Optical Transistors the Logical Next Step? Nat. Photonics 2010, 4, 3-5. (14) Zhang, C.; Yan, Y.; Yao, J.; Zhao, Y. S. Manipulation of Light Flows in Organic ColorGraded Microstructures Towards Integrated Photonic Heterojunction Devices. Adv Mater 2013, 25, 2854-2859. (15) McEvoy, M. A.; Correll, N. Materials Science. Materials That Couple Sensing, Actuation, Computation, and Communication. Science 2015, 347, 1261689. (16) Makarov, S. V.; Zalogina, A. S.; Tajik, M.; Zuev, D. A.; Rybin, M. V.; Kuchmizhak, A. A.; Juodkazis, S.; Kivshar, Y. Light-Induced Tuning and Reconfiguration of Nanophotonic Structures. Laser Photonics Rev. 2017, 11. (17) Liu, A. Q.; Zhu, W. M.; Tsai, D. P.; Zheludev, N. I. Micromachined Tunable Metamaterials: A Review. J. Opt. 2012, 14. (18) Overvelde, J. T.; de Jong, T. A.; Shevchenko, Y.; Becerra, S. A.; Whitesides, G. M.; Weaver, J. C.; Hoberman, C.; Bertoldi, K. A Three-Dimensional Actuated Origami-Inspired Transformable Metamaterial with Multiple Degrees of Freedom. Nat Commun 2016, 7, 10929.


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Page 22 of 23

(19) Gutruf, P.; Zou, C.; Withayachumnankul, W.; Bhaskaran, M.; Sriram, S.; Fumeaux, C. Mechanically Tunable Dielectric Resonator Metasurfaces at Visible Frequencies. ACS Nano 2016, 10, 133-141. (20) Pryce, I. M.; Aydin, K.; Kelaita, Y. A.; Briggs, R. M.; Atwater, H. A. Highly Strained Compliant Optical Metamaterials with Large Frequency Tunability. Nano Lett 2010, 10, 42224227. (21) Zhu, L.; Kapraun, J.; Ferrara, J.; Chang-Hasnain, C. J. Flexible Photonic Metastructures for Tunable Coloration. Optica 2015, 2, 255-258. (22) Sautter, J.; Staude, I.; Decker, M.; Rusak, E.; Neshev, D. N.; Brener, I.; Kivshar, Y. S. Active Tuning of All-Dielectric Metasurfaces. ACS Nano 2015, 9, 4308-4315. (23) Liao, Q.; Fu, H.; Wang, C.; Yao, J. Cooperative Assembly of Binary Molecular Components into Tubular Structures for Multiple Photonic Applications. Angew Chem Int Ed Engl 2011, 50, 4942-4946. (24) Chen, P.-Z.; Zhang, H.; Niu, L.-Y.; Zhang, Y.; Chen, Y.-Z.; Fu, H.-B.; Yang, Q.-Z. A SolidState Fluorescent Material Based on Carbazole-Containing Difluoroboron Β-Diketonate: Multiple Chromisms, the Self-Assembly Behavior, and Optical Waveguides. Adv. Funct. Mater. 2017, 27. (25) Sun, C. L.; Gao, Z.; Teng, K. X.; Niu, L. Y.; Chen, Y. Z.; Zhao, Y. S.; Yang, Q. Z. Supramolecular Polymer-Based Fluorescent Microfibers for Switchable Optical Waveguides. ACS Appl. Mater. Interfaces 2018, 10, 26526-26532. (26) Juodkazis, S.; Mizeikis, V.; Misawa, H. Three-Dimensional Microfabrication of Materials by Femtosecond Lasers for Photonics Applications. J. Appl. Phys. 2009, 106. (27) Hon, K. K. B.; Li, L.; Hutchings, I. M. Direct Writing Technology—Advances and Developments. CIRP Ann. 2008, 57, 601-620. (28) Singh-Gasson, S.; Green, R. D.; Yue, Y.; Nelson, C.; Blattner, F.; Sussman, M. R.; Cerrina, F. Maskless Fabrication of Light-Directed Oligonucleotide Microarrays Using a Digital Micromirror Array. Nat Biotechnol 1999, 17, 974-978. (29) Liu, C.; Liang, G.; Liu, Z.; Zu, L. Time-Resolved Fluorescence Anisotropy Study of the Interaction between DNA and a Peptide Truncated from the P53 Protein Core Domain. J Fluoresc 2014, 24, 533-539. (30) Holm, A. K.; Mohammed, O. F.; Rini, M.; Mukhtar, E.; Nibbering, E. T.; Fidder, H. Sequential Merocyanine Product Isomerization Following Femtosecond Uv Excitation of a Spiropyran. J Phys Chem A 2005, 109, 8962-8968. (31) Jang, A. R.; Jeon, E. K.; Kang, D.; Kim, G.; Kim, B. S.; Kang, D. J.; Shin, H. S. Reversibly Light-Modulated Dirac Point of Graphene Functionalized with Spiropyran. ACS Nano 2012, 6, 9207-9213. (32) Ivashenko, O.; van Herpt, J. T.; Feringa, B. L.; Rudolf, P.; Browne, W. R. Uv/Vis and Nir Light-Responsive Spiropyran Self-Assembled Monolayers. Langmuir 2013, 29, 4290-4297. (33) Kohl-Landgraf, J.; Braun, M.; Ozcoban, C.; Goncalves, D. P.; Heckel, A.; Wachtveitl, J. Ultrafast Dynamics of a Spiropyran in Water. J Am Chem Soc 2012, 134, 14070-14077. (34) O'Carroll, D.; Lieberwirth, I.; Redmond, G. Melt-Processed Polyfluorene Nanowires as Active Waveguides. Small 2007, 3, 1178-1183. (35) Xu, Y.; Gu, C.; Hou, B.; Lai, Y.; Li, J.; Chen, H. Broadband Asymmetric Waveguiding of Light without Polarization Limitations. Nat Commun 2013, 4, 2561.


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(36) Xu, J.; Zhuang, X.; Guo, P.; Huang, W.; Hu, W.; Zhang, Q.; Wan, Q.; Zhu, X.; Yang, Z.; Tong, L.; Duan, X.; Pan, A. Asymmetric Light Propagation in Composition-Graded Semiconductor Nanowires. Sci Rep 2012, 2, 820. (37) Kurt, H.; Yilmaz, D.; Akosman, A. E.; Ozbay, E. Asymmetric Light Propagation in Chirped Photonic Crystal Waveguides. Opt Express 2012, 20, 20635-20646.

ToC graphic：


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One-Dimensional Programmable Polymeric Microfiber Waveguide

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