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Control over material architectures is essential to the performance of photonic devices and systems. Optical isolation of the photonic materials from substrates can significantly enhance their performance but suffers from complicated fabrication processes and limited applications. Here a differential polymer chain scission strategy is proposed to fabricate free-standing photonic structures based on one-step electron-beam direct writing on polymer bilayers (EOB). The polymer molecular mass-dependent sensitivity to electron beam enables differential patterning of the two layers of polymers, leading to the direct formation of suspended optical microcavities. The EOB technique features high materials compatibility and design flexibility for the optical microcavities, which significantly expands the application scope of the suspended optical microcavities. As well as providing a versatile strategy for building high-performance photonic materials, the results provide a promising platform for innovative applications of optical microstructures.

Exciton-polaritons are half-light, half-matter bosonic quasiparticles formed by strong exciton-photon coupling in semiconductor microcavities. These hybrid particles possess the strong nonlinear interactions of excitons and keep most of the characteristics of the underlying photons. As bosons, above a threshold density they can undergo Bose-Einstein condensation to a polariton condensate phase and exhibit a rich variety of exotic macroscopic quantum phenomena in solids. Recently, organic semiconductors have been considered as a promising material platform for these studies due to their room-temperature stability, good processability, and abundant photophysics and photochemistry. Herein, recent advances of exciton-polaritons and their Bose-Einstein condensates in organic semiconductor microcavities are summarized. First, the basic physics is introduced, and then their emerging applications are highlighted. The remaining questions are also discussed and a personal viewpoint about the potential directions for future research is given.

3D laser displays play an important role in next-generation display technologies owing to the ultimate visual experience they provide. Circularly polarized (CP) laser emissions, featuring optical rotatory power and invariability under rotations, are attractive for 3D displays due to potential in enhancing contrast ratio and comfortability. However, the lack of pixelated self-emissive CP microlaser arrays as display panels hinders the implementation of 3D laser displays. Here, full-color 3D laser displays are demonstrated based on CP lasing with inkjet-printed cholesteric liquid crystal (CLC) arrays as display panels. Individual CP lasers are realized by embedding fluorescent dyes into CLCs with their left-/right-handed helical superstructures serving as distributed feedback microcavities, bringing in ultrahigh circular polarization degree values (gem = 1.6). These CP microlaser pixels exhibit excellent far-field color-rendering features and a relatively large color gamut for high-fidelity displays. With these printed CLC red-green-blue (RGB) microlaser arrays serving as display panels, proof-of-concept full-color 3D laser displays are demonstrated via delivering images with orthogonal CP laser emissions into one's left and right eyes. These results provide valuable enlightenment for the development of 3D laser displays.

Anticounterfeiting labels based on physical unclonable functions (PUFs) exhibit high security with unreplicable code outputs, making them an ideal platform to realize unbreakable anticounterfeiting. Although various schemes are proposed for PUF labels, the utilization of natural randomness suffers from unpredictable signal extraction sites, which poses a challenge to efficient and convenient authentication for practical anticounterfeiting applications. Here, a covert optical PUF-based cryptographic protocol from silk protein-based microlaser (SML) arrays that possess hidden randomness of lasers for unclonable lasing signals as well as a defined location for efficient identification is proposed. The initial SMLs are patterned by casting laser dye-doped regenerated silk fibroin solution, resulting in a uniform microlaser array with regulated positions. With the SML array as substrate, random methanol microdroplets are stochastically sprayed on the SML array, which eventually induces uneven lasing signal changes of the patterned microlasers. The treated SML array possesses the deterministic readout sites of laser signals and unrepeatable signal distribution characteristics, which can guarantee efficient authentication and high security when serving as an anticounterfeiting label.

Synthesis of novel mesoscopic semiconductor architectures continually generates new photonic knowledge and applications. However, it remains a great challenge to synthesize semiconductor microcrystals with smoothly curved surfaces owing to the crystal growth anisotropy. Here, a superkinetic crystal growth method is developed to synthesize 2D oval organic semiconductor microcrystals. The solid source dispersion induces an exceptionally large molecular supersaturation for vapor deposition, which breaks the crystal growth anisotropy. The synthesized stadium-shaped organic semiconductor microcrystals naturally constitute fully chaotic optical microresonators. They support low-threshold lasing on high-quality-factor scar modes localized near the stadium boundary and directional laser emission assisted by the chaotic modes. These results will reshape the understanding of the crystal growth theory and provide valuable guidance for crystalline photonic materials design.

Halide perovskites have shown tremendous potential for next-generation flat-panel laser displays due to their remarkable optoelectronic properties and outstanding material processability; however, the lack of a general approach for the fast growth of perovskite laser arrays capable of electrical operations impedes actualization of their display applications. Herein, a universal and robust wettability-guided screen-printing technique is reported for the rapid growth of large-scale multicolor perovskite microdisk laser arrays, which can serve as laser display panels and further be used to realize current-driven displays. The perovskite microlasers are precisely defined with controlled physical dimensions and spatial locations by such a printing strategy, and each perovskite microlaser serves as a pixel of a display panel. Moreover, the screen-printing procedure is highly compatible with light-emitting diode (LED) device architectures, which is favorable for the mass production of micro-LED arrays. On this basis, a prototype of a current-driven display is demonstrated with desired functionalities. The outstanding performance and feasible fabrication of screen-printed perovskite microlaser arrays embedded in LEDs provide deep insights into the concepts and device architectures of electrically driven laser display technology.

Photonic barcodes with a small footprint have demonstrated a great value for multiplexed high-throughput bioassays and tracking systems. Attempts to develop coding technology tend to focus on the generation of featured barcodes both with high coding capacity and accurate recognition. In this work, a strategy to design photonic barcodes is proposed based on whispering-gallery-mode (WGM) modulations in dye-doped microdisk resonant cavities, where each modulated photoluminescence spectrum constitutes the fingerprint of a corresponding microdisk. The WGM-based barcodes can achieve infinite encoding capacity through tuning the dimensions of the microdisks. These photonic barcodes can be well disguised and decoded based on the light controlled proton release and acidichromism of the organic materials, which are essential to fulfill the functions of anti-counterfeiting, information security, and so on. The results will pave an avenue to new types of flexible WGM-based components for optical data recording and security labels.

A wavelength-tunable microlaser is realized based on the controlled intramolecular charge transfer (ICT) process in dye-encapsulated metal-organic framework (MOF) material. The confinement effect of the MOFs is beneficial for low-threshold lasing. By effectively controlling the polarity of the MOF pores, the population distribution between the locally excited and ICT states is continuously modulated, thus achieving broadband tunable MOF-based microlasers.

Organic nanomaterials have drawn great interest for their potential applications in high-speed miniaturized photonic integration due to their high photoluminescence quantum efficiency, structural processability, ultrafast photoresponse, and excellent property engineering. Based on the rational design on morphological and componential levels, a series of organic nanomaterials have been controllably synthesized in recent years, and their excitonic/photonic behaviors has been fine-tuned to steer the light flow for specific optical applications. This review presents a comprehensive summary of recent breakthroughs in the controlled synthesis of organic nanomaterials with specific structures and compositions, whose tunable photonic properties would provide a novel platform for multifunctional applications. First, we give a general overview of the tailored construction of novel nanostructures with various photonic properties. Then, we summarize the design and controllable synthesis of composite materials for the modulation of their functionalities. Subsequently, special emphasis is put on the fabrication of complex nanostructures towards wide applications in isolated photonic devices. We conclude with our personal viewpoints on the development directions in the novel design and controllable construction of organic nanomaterials for future applications in highly integrated photonic devices and chips.

Many recent activities in the use of one-dimensional nanostructures as photonic elements for optical information processing are explained by huge advantages that photonic circuits possess over traditional silicon-based electronic ones in bandwidth, heat dissipation, and resistance to electromagnetic wave interference. Organic materials are a promising candidate to support these optical-related applications, as they combine the properties of plastics with broad spectral tunability, high optical cross-section, easy fabrication, as well as low cost. Their outstanding compatibility allows organic composite structures which are made of two or more kinds of materials combined together, showing great superiority to single-component materials due to the introduced interactions among multiple constituents, such as energy transfer, electron transfer, exciton coupling, etc. The easy processability of organic 1D crystalline heterostructures enables a fine topological control of both composition and geometry, which offsets the intrinsic deficiencies of individual material. At the same time, the strong exciton-photon coupling and exciton-exciton interaction impart the excellent confinement of photons in organic microstructures, thus light can be manipulated according to our intention to realize specific functions. These collective properties indicate a potential utility of organic heterogeneous material for miniaturized photonic circuitry. Herein, focus is given on recent advances of 1D organic crystalline heterostructures, with special emphasis on the novel design, controllable construction, diverse performance, as well as wide applications in isolated photonic elements for integration. It is proposed that the highly coupled, hybrid optical networks would be an important material basis towards the creation of on-chip optical information processing.

Surface plasmon polaritons (SPPs) can be launched with an organic nanowire that serves as both light source and dielectric waveguide in a single organic/metal nanowire heterojunction. Efficient modulation of the output signals from the silver tip can be achieved via the alternation of incident polarizations, which is further used to design and realize prototypical photonic-plasmonic logic devices. These findings are essential for incorporating plasmonic waveguides as practical components into hybrid high-capacity photonic circuits.

Continuing efforts have been focused on detecting H 2 O 2 by different strategies such as infrared/Raman spectroscopy, [ 4 ] mass spectrometry, [ 5 ] electrochemical method, [ 6 ] colorimetric [ 7 ] and fl uorimetric detection. [ 8 ] Generally these methods either require expensive bulky equipment and tedious sample preparation, or have poor selectivity and limits of detection. Therefore, the development of contrast agents that allow the expedient detection of H 2 O 2 at low concentration is in demand. Peroxalate ester and its derivatives are typical chemiluminogenic compounds highly sensitive to H 2 O 2 . [ 9 ] The reaction between peroxalate ester groups and H 2 O 2 can generate a high-energy intermediate that may transfer energy to the fl uorescent dye, resulting in effi cient luminescence. This has been proved to be a promising strategy for the expedient and sensitive detecting of H 2 O 2 . [ 1 , 10 ]

polymers, [ 5 ] and small organic molecules [ 6–11 ] are widely investigated for their applications in optoelectronic communications and sensors. [ 12 , 13 ] The semiconductor and metal waveguides are based on the propagation of photons and surface plasmon polaritons (SPPs), respectively. Very recently, it was proposed that organic waveguide materials work with a distinct principle, i.e., exciton polaritons (EPs) formed by the strong coupling between Frenkel excitons and photons play an essential role in organic optical waveguides. [ 14 ] Due to the photon–exciton coupling, EPs show excellent propagation properties compared with uncoupled light. [ 15 ] Moreover, the participation of excitons might introduce interesting electron and energy processes during propagation, which are helpful for the realization of novel waveguide behaviors. Excitons can be converted between two organic compounds accompanied by energy transfers, through which white light emissions (WLEs) can be achieved. [ 16 ] As devices are being designed on ever diminishing scales, WLE sub-wavelength waveguides are desired as small white light generators in micro-photonic circuits. In general, white lights are generated by the incomplete quenching of donor emissions and the color mixing of donors and acceptors at given doping ratios by either singlet–singlet (SSET), [ 17 ] or triplet–triplet energy transfer (TTET). [ 18 ] However, this strategy is greatly limited in constructing single nanowire WLE waveguides in that the color is supersensitive to the doping ratio, and a slight change of acceptor content by environmental heating, oxidation, or light irradiation in practical applications will signifi cantly infl uence the white light output. [ 19 ] Inspired by the voltage stabilizer in electric circuits, herein we demonstrate a kind of optical modulator based on doped organic nanowire waveguides, which can output constant white light from the wire terminus, despite the doping contents. The modulation was realized by the fl uctuations of singlet and triplet excitons during EP propagation as