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In the field of information processing, all-optical routers are significant for achieving high-speed, high-capacity signal processing and transmission. In this study, we developed three types of structurally simple and flexible routers using the deep diffractive neural network (D2NN), capable of routing incident light based on wavelength and polarization. First, we implemented a polarization router for routing two orthogonally polarized light beams. The second type is the wavelength router that can route light with wavelengths of 1550, 1300, and 1100 nm, demonstrating outstanding performance with insertion loss as low as 0.013 dB and an extinction ratio of up to 18.96 dB, while also maintaining excellent polarization preservation. The final router is the polarization-wavelength composite router, capable of routing six types of input light formed by pairwise combinations of three wavelengths (1550, 1300, and 1100 nm) and two orthogonal linearly polarized lights, thereby enhancing the information processing capability of the device. These devices feature compact structures, maintaining high contrast while exhibiting low loss and passive characteristics, making them suitable for integration into future optical components. This study introduces new avenues and methodologies to enhance performance and broaden the applications of future optical information processing systems.

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Two-dimensional (2D) materials with atomic thickness, tunable light-matter interaction, and significant nonlinear susceptibility are emerging as potential candidates for new-generation optoelectronic devices. In this review, we briefly cover the recent research development of typical nonlinear optic (NLO) processes including second harmonic generation (SHG), third harmonic generation (THG), as well as two-photon photoluminescence (2PPL) of 2D materials. Nonlinear light-matter interaction in atomically thin 2D materials is important for both fundamental research and future optoelectronic devices. The NLO performance of 2D materials can be greatly modulated with methods such as carrier injection tuning, strain tuning, artificially stacking, as well as plasmonic resonant enhancement. This review will discuss various nonlinear optical processes and corresponding tuning methods and propose its potential NLO application of 2D materials.

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Self-supporting gold nanowire (AuNW) gratings with a thickness of about 200 nm are produced by solution-processing and flexible-transfer techniques. Such an ultrathin structure is applied as an ultrafast optical switch that enables low-threshold optical modulation with a high signal contrast and a high signal-to-noise ratio. Transient energy-band modification in gold under excitation by femtosecond laser pulses is the main responsible mechanism. For a pump fluence of about 170 µJ cm-2, a modulation depth of about 10% is achieved for the optical switching signal. Self-supporting metallic plasmonic photonic thin films with a large area and flexible structures are important for applications in a large variety of circumstances and on different interfaces for optical signal processing, optical logic circuits, and optical communication systems.

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Hydrates of hybrid organic-inorganic perovskites have been discovered with MAPbI3 and are proved to be unstable in atmosphere. However, the influence of water molecules on the performance of optoelectronic devices is still not fully understood. Here, using a dication, 2-(dimethylamino) ethylamine (DMEN2+ ), a stable quasi-1D perovskitoid hydrate single crystal is designed and successfully synthesized, which is formulated as DMENPb2 I6 ·H2 O. In this design, both corner-sharing and edge-sharing connectivity are adopted, and water molecules are connected with the crystal through hydrogen bonding. It is discovered that such water sites distributed along the inorganic chains function both as charge traps and as releasable charge stocks. Optical excitation that overcomes the potential wells formed on these water sites may release these stocked charges and facilitate enhanced transportable charge density. Meanwhile, exciton diffusion and charge transport are strongly confined in the 1D transport channels. Above mechanisms are verified both by the transient absorption spectroscopy and by the photodetection performance. This introduces a new design strategy with a trapping-stock-releasing-transport roadmap for perovskitoid materials. Excellent water resistance endows this material with more advantages in the development of a new generation of optoelectronic devices.

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BACKGROUND: Ovarian cancer is a malignant tumor with a poor prognosis, its underlying mechanism is still unclear. OBJECTIVE: In this study, long noncoding RNA DARS-AS1 was studied to identify its function in the development of ovarian cancer. METHODS: Perform functional experiments to detect the effects of DARS-AS1 on the proliferation, apoptosis, and migration of ovarian cancer cells A2780. The luciferase report, immunoprecipitation (IP) experiment, and ubiquitination level determination verify that RBX1 ubiquitination and mediate the degradation of tumor suppressor gene TP53. RESULTS: Knockdown of DARS-AS1 can inhibit cell proliferation, migration, and apoptosis, and the application of miR-194-5p inhibitors can prevent this process. Luciferase and IP experiments showed that DARS-AS1 regulates the expression of RBX1 by binding to miR-194-5p, and RBX1 mediates its degradation through ubiquitination of TP53.

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We present experimental and theoretical investigations of the photophysics in the one-dimensional (1D) hybrid organic-inorganic perovskite (HOIP) white-light emitter, [DMEDA]PbBr4. It is found that the broadband-emission nature of the 1D perovskite is similar to the case of two-dimensional (2D) HOIP materials, exciton self-trapping (ST) is the dominant mechanism. By comprehensive spectroscopic investigations, we observed direct evidence of exciton crossing the energy barrier separating free and ST states through quantum tunnelling. Moreover, we consider the lattice shrinking mechanisms at low temperatures and interpret the ST exciton formation process using a configuration coordinate diagram. We propose that the energy barrier separating free and ST excitons is temperature-dependent, and consequently, the manner of excitons crossing it is highly dependent on the exciting energy and temperature. For excitons located at the bottom of the free excitonic states, the quantum tunnelling is the dominant channel to the ST states.

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Charge-transfer states have been observed extensively in heterojunctions of organic semiconductors, which are also referred to as exciplexes in polymer blends. Such mechanisms have been well understood in the conventional material systems. However, electromer states may be produced only in some polymeric molecules with folded chains. We report here the interaction between exciplex and electromer states, which facilitates the formation of a new electrically excited state that we define as a secondary exciplex. This is an indirect process understood as an electromer-mediated heterojunction. We discovered such an optoelectronic mechanism in the blend film of poly(9,9'-dioctylfluorene-co-bis-N,N'-(4-butylphenyl)-bis-N,N'-pheny-l,4-phenylene-diamine) (PFB) and poly[(9,9-dioctylfluorenyl-2,7-diyl)-alt-(benzo[2,1,3]thiadiazol-4,8-diyl)] (F8BT). Four emission bands can be resolved from the electroluminescence spectrum, including those based on the excitons, the electromers, and the primary and secondary exciplexes. The whole electroluminescence spectrum thus extends from the green (500 nm) to the near-infrared (900 nm) with a full bandwidth of 400 nm. These new discoveries with the conventional light-emitting polymers are important not only for polymeric optoelectronics, but also for the development of broadband light-emitting devices.

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A spatially pinned surface plasmon is constructed by connecting a gold nanoshell grating with a planar gold nanofilm, forming a periodical array of gold nanoloops. Dramatic electric field modulation and high charge carrier density on the contact sites enable balanced plasmonic electron distribution over the spatially pinned nanostructures. Compared with its counterpart, spacer-supported double-layer surface plasmon polaritons (SPPs), the pinned structure not only changed the electronic oscillation channels but also short-circuited the propagating SPPs at the top and bottom interfaces. Ultrafast spectroscopic dynamics identified a much-extended relaxation lifetime of the pinned plasmon and revealed a holding time as long as 1.3 ps for the double-layer SPPs, which was sustained by microcavities based on distributed optical feedback. These results introduced a new type of surface plasmon and a new design of time retarders for optical logic circuits.

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In a two-dimensional non-Hermitian topological photonic system, the physics of topological states is complicated, which brings great challenges for clarifying the topological phase transitions and achieving precise active control. Here, we prove the topological phase transition exists in a two-dimensional parity-time-symmetric coupled-resonator optical waveguide system. We reveal the inherent condition of the appearance of topological phase transition, which is described by the analytical algebraic relation of coupling strength and the quantity of gain-loss. In this framework, the system can be switched between the topological and trivial states by pumping the site rings. This work provides a new degree of freedom to control topological states and offers a scheme for studying non-Hermitian topological photonics.

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Vanadium dioxide (VO2) attracts great attention due to its well-known metal-to-insulator transition. However, traditional VO2 films grown on rigid substrates are inflexible, which limits their applications. In this work, we successfully prepared VO2/silicon nitride (VO2/SN) composite films by a simple template method. The VO2/SN film shows high flexibility, strong infrared absorption, and drastic resistance change (>103) induced by the phase transition. The application of the VO2/SN film is presented by infrared sensing, which shows a high responsivity (720 V W-1) and short response time (409 ms).

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Strong optical excitation of plasmonic nanostructures may induce simultaneous interband and intraband electronic transitions. However, interaction mechanisms between interband, intraband, and plasmon-band processes have not been thoroughly understood. In particular, optical-heating-induced lattice expansion, which definitely leads to shift of the Fermi level, has not been taken into account in plasmonic studies. Here, it is shown that plasmonic bandedge shift is responsible for the optical modulation on the boundary between plasmonic electron oscillation and interband transitions via investigations on gold nanofilms and nanoparticles. Strong optical excitation induces transient depletion of the conduction band just below the Fermi level through intraband transitions, while the subsequent lattice heating induces transient thermal expansion and hence lowers the Fermi level. Both effects reduce the threshold for interband transitions and therefore push the plasmonic bandedge to the red. These discoveries introduce a first correlation between plasmonic response and optical excitation induced thermal expansion of lattices. The revealed Fermi-level adjustment mechanism allows alignment of electronic levels at the metal-semiconductor interfaces, which applies to all conductive materials and renders reliable physics for the design of plasmonic or optoelectronic devices.

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Considerable research efforts have been devoted to the investigation of distributed feedback (DFB) organic lasing in photonic crystals in recent decades. It is still a big challenge to realize DFB lasing in complex photonic crystals. This review discusses the recent progress on the DFB organic laser based on one-, two-, and three-dimensional photonic crystals. The photophysics of gain materials and the fabrication of laser cavities are also introduced. At last, future development trends of the lasers are prospected.

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A random laser was achieved in a polymer membrane with silver nanoflowers on a flexible substrate. The strong confinement of the polymer waveguide and the localized field enhancement of silver nanoflowers were essential for the low-threshold random lasing action. The lasing wavelength can be tuned by bending the flexible substrate. The solution phase synthesis of the silver nanoflowers enables easy realization of this type of random lasers. The flexible and high-efficiency random lasers provide favorable factors for the development of imaging and sensing devices.

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Structural coloration has attracted great interest from scientists and engineers in recent years, owing to fascination with various brilliant examples displayed in nature as well as to promising applications of bio-inspired functional photonic structures and materials. Much research has been done to reveal and emulate the physical mechanisms that underlie the structural colors found in nature. In this article, we review the fundamental physics of many natural structural colors displayed by living organisms as well as their bio-inspired artificial counterparts, with emphasis on their connections, tunability strategies, and proposed applications, which aim to maximize the technological benefits one could derive from these photonic nanostructures. WIREs Nanomed Nanobiotechnol 2016, 8:758-775. doi: 10.1002/wnan.1396 For further resources related to this article, please visit the WIREs website.

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Colloidal quantum dot (CQD) solar cells have attracted tremendous attention because of their tunable absorption spectrum window and potentially low processing cost. Recently reported quantum junction solar cells represent a promising approach to building a rectifying photovoltaic device that employs CQD layers on each side of the p-n junction. However, the ultimate efficiency of CQD solar cells is still highly limited by their high trap state density in both p- and n-type CQDs. By modeling photonic structures to enhance the light absorption within the carrier transport length and by ensuring that the carrier generation and collection efficiencies were both augmented, our work shows that overall device current density could be improved. We utilized a two-dimensional numerical model to calculate the characteristics of patterned CQD solar cells based on a simple grating structure. Our calculation predicts a short circuit current density as high as 31 mA/cm2, a value nearly 1.5 times larger than that of the conventional flat design, showing the great potential value of patterned quantum junction solar cells.

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Colloidal quantum dot (CQD) solar cells have attracted tremendous attention mostly due to their wide absorption spectrum window and potentially low processability cost. The ultimate efficiency of CQD solar cells is highly limited by their high trap state density. Here we show that the overall device power conversion efficiency could be improved by employing photonic structures that enhance both charge generation and collection efficiencies. By employing a two-dimensional numerical model, we have calculated the characteristics of patterned CQD solar cells based of a simple grating structure. Our calculation predicts a power conversion efficiency as high as 11.2%, with a short circuit current density of 35.2 mA/cm2, a value nearly 1.5 times larger than the conventional flat design, showing the great potential value of patterned quantum dot solar cells.

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Shape memory polymers (SMPs) have been shown to accurately replicate photonic structures that produce tunable optical responses, but in practice, these responses are limited by the irreversibility of conventional shape memory processes. Here, we report the intensity modulation of a diffraction grating utilizing two-way reversible shape changes. Reversible shifting of the grating height was accomplished through partial melting and recrystallization of semicrystalline poly(octylene adipate). The concurrent variations of the grating shape and diffraction intensity were monitored via atomic force microscopy and first order diffraction measurements, respectively. A maximum reversibility of the diffraction intensity of 36% was repeatable over multiple cycles. To that end, the reversible shape memory process is shown to broaden the functionality of SMP-based optical devices.

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Key message: Pollen maturation in Poaceae. Another development has been extensively examined by various imaging tools, including transmission electron microscopy, scanning electron microscopy, and light microscopy, but none is capable of identifying liquid water. Cryo-scanning electron microscopy with high-pressure rapid freeze fixation is excellent in preserving structures at cellular level and differentiating gas- versus liquid-filled space, but rarely used in anther study. We applied this technique to examine anther development of Poaceae because of its economic importance and unusual peripheral arrangement of pollen. Maize and longstamen rice were focused on. Here, we report for the first time that anthers of Poaceae lose the locular free liquid during late-microspore to early pollen stages; the majority of pollen grains arranged in a tight peripheral whorl develops normally and reaches maturity in the gas-filled loculus. Occasionally, pollen grains are found situated in the locular cavity, but they remain immature or become shrunk at anthesis. At pollen stage, microchannels and cytoplasmic strands are densely distributed in the entire pollen exine and intine, respectively, suggesting that nutrients are transported into the pollen from the entire surface. We propose that in Poaceae, the specialized peripheral arrangement of pollen grains is crucial for pollen maturation in the gas-filled loculus, which enables pollen achieving large surface contact area with the tapetum and neighboring grains to maintain sufficient nutrient flow. This report also shows that the single aperture of pollen in Poaceae usually faces the tapetum, but other orientation is also common; pollen grains with different aperture orientations show no morphological differences.

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OBJECTIVE: To investigate human papilloma virus (HPV) infection and typing in 7 640 cases of women in Shanxi province in order to provide theoretical basis for the prevention and treatment of the cervical cancer. METHODS: Totally, 7 640 cases of cervical cell specimens in Shanxi provincial tumor hospital, screening and physical examination from 2012 January to 2013 May and 23 HPV genotypes were analyzed by PCR and reverse dot blot gene chip technology. RESULTS: A total of 1 441 cases of patients with HPV infection were to be found in 7 640 cases of women with an average age of (42.26 ± 19.15)years old. The total infection positive rate, infection rate of high-risk HPV, infection rate of low-risk HPV and infection rate of mixed high and low risk were 18.86% (1 441/7 640), 16.03% (1 225/7 640, including multiple high-risk of HPV infection), 4.88% (373/7 640, including multiple low-risk of HPV infection) and 2.05% (157/7 640) respectively. The rate of high-risk HPV infection was 85.01% (1 225/1 441) in total infection positive women. The most common subtype was HPV16 (34.70%, 523/1 507) and followed by HPV58 (11.48%, 173/1 507), HPV18 (7.43%, 112/1 507), HPV33 (7.10%, 107/1 507), HPV56 (6.04%, 91/1 507) and HPV52 (5.51%, 83/1 507) respectively in tested 18 high-risk HPV subtypes, and there was no HPV82. The most common subtype was HPV43 (38.13%, 151/396) and followed by HPV42 (22.22%, 88/396), HPV81 (20.45%, 81/396), HPV6 (11.87%, 47/396) and HPV11 (7.32%, 29/396) respectively in tested 5 low-risk HPV subtypes. The HPV infection positive rates were significantly different in different age groups and HPV total infection rate, high-risk infection rate in 41-50 year-old age group was the highest, 23.23%. The infection rates of single subtype of HPV and single high-risk subtype of HPV were 75.71% (1 091/1 441) and 61.35% (884/1 441) respectively in all cases of infection women and single high-risk subtype infection rate was 81.03% (884/1 091) in all cases of single subtype infection women. The infection rate of multiple subtype of HPV was 24.29% (350/1 441) in all cases with HPV infection. The double infections was most common (18.18%, 262/1 441) in which the women of double high-risk infections of HPV were 151 cases (10.48%, 151/1 441). The rates of double infection, triple infection and quadruple or more infection of HPV were 74.86% (262/350), 20.29% (71/350) and 4.89% (17/350) respectively in all cases with HPV multiple infection. The positive rates of HPV infection in different age groups were obvious difference. The positive rate of single infection of HPV was 17.80% (574/3 224) in cases of 41-50 years old group which higher than that in other groups(χ² = 20.18, P < 0.05). CONCLUSION: The more common high-risk HPV subtype is HPV16, HPV58, HPV18, HPV33, HPV56 and HPV52 and low-risk HPV subtype is HPV43, HPV42 in Shanxi province. HPV infection is most common in the age group of 41- 50 years old female.

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Actively all-optical tunable plasmon-induced transparency in metamaterials paves the way for achieving ultrahigh-speed quantum information processing chips. Unfortunately, up to now, very small experimental progress has been made for all-optical tunable plasmon-induced transparency in metamaterials in the visible and near-infrared range because of small third-order optical nonlinearity of conventional materials. The achieved operating pump intensity was as high as several GW/cm(2) order. Here, we report an ultralow-power and ultrafast all-optical tunable plasmon-induced transparency in metamaterials coated on polycrystalline indium-tin oxide layer at the optical communication range. Compared with previous reports, the threshold pump intensity is reduced by four orders of magnitude, while an ultrafast response time of picoseconds order is maintained. This work not only offers a way to constructing photonic materials with large nonlinearity and ultrafast response, but also opens up the possibility for realizing quantum solid chips and ultrafast integrated photonic devices based on metamaterials.

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