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Stochastic computing is a non‐traditional computing approach that utilizes stochastic bitstreams to represent numerical values. This representation enables the implementation of circuits using basic logic gates, named stochastic circuits. This work proposes a versatile architecture with correlated input bitstreams for biased accumulation. The design offers a notable reduction in the reliance on random number generators, resulting in lower hardware costs and higher computing accuracy when compared with the existing designs. Experimental results show that the application of Gaussian smoothing has a reduction in area by at least 45% and an improvement in peak signal‐to‐noise ratio of at least 30%. [ABSTRACT FROM AUTHOR]

Cyclobutanes with a gem‐dimethyl group are common motifs in natural products. However, strategies for constructing enantioenriched gem‐dimethyl cyclobutanes are still underdeveloped. Herein, we report an enantioselective approach to synthesize a broad group of chiral 2,3‐disubstituted cyclobutanones through sequential 1,4‐conjugate addition/trapping/cross‐coupling of readily available cyclobutenones. The intermediate 2‐bromocyclobutanone provides a valuable synthetic handle for further coupling transformations. In addition, this strategy was successfully utilized to synthesize gem‐dimethyl cyclobutane‐containing natural products, including (+)‐β‐caryophyllene, (−)‐raikovenal, (−)‐1β,9αH‐5‐linoleoyloxy‐4,5‐secocaryophyllen‐4‐one, and (−)‐rumphellanones A−C. [ABSTRACT FROM AUTHOR]

Cyclobutanes with a gem‐dimethyl group are common motifs in natural products. However, strategies for constructing enantioenriched gem‐dimethyl cyclobutanes are still underdeveloped. Herein, we report an enantioselective approach to synthesize a broad group of chiral 2,3‐disubstituted cyclobutanones through sequential 1,4‐conjugate addition/trapping/cross‐coupling of readily available cyclobutenones. The intermediate 2‐bromocyclobutanone provides a valuable synthetic handle for further coupling transformations. In addition, this strategy was successfully utilized to synthesize gem‐dimethyl cyclobutane‐containing natural products, including (+)‐β‐caryophyllene, (−)‐raikovenal, (−)‐1β,9αH‐5‐linoleoyloxy‐4,5‐secocaryophyllen‐4‐one, and (−)‐rumphellanones A−C. [ABSTRACT FROM AUTHOR]

Stochastic computing (SC) encodes numerical values into probabilistic binary bitstreams to enable complex arithmetic operations to be transformed into simple bit operations. Different operations can be performed through the same SC element by adjusting the correlation between bitstreams. In this work, two stochastic mean circuits (MCs) are proposed by manipulating positively and negatively correlated bitstreams, respectively named PCMC and NCMC, to improve computing accuracy, lower area, and power consumption. Furthermore, a general structure for MCs, denoted as GMC, is also proposed to generalize their design approach. Compared with the existing multiplexer (MUX)‐based stochastic MCs, the proposed circuits have approximately 50%, 59%, 61%, and 64% reduction in area, and 100×, 10×, 151×, and 12 × improvement in MSE, for 2‐, 3‐, 4‐, and 5‐input situations, respectively. With applications to edge detection and mean filtering, the proposed designs are superior to the existing counterparts in terms of accuracy and hardware cost. [ABSTRACT FROM AUTHOR]

Stochastic computing (SC) is an approximate computing paradigm using probabilities and aims at realizing circuits with low hardware cost. Basic operations (such as addition) have been comprehensively studied, whereas there are few studies on nonlinear operations (such as division and square root) in SC. In this paper, a stochastic division circuit is proposed by using maximally correlated input bitstreams to eliminate the necessity for distinguishing the divisor and dividend. Additionally, four stochastic square root circuits are designed with improved accuracy by decreasing the correlation between intermediate bitstreams via inserting delay elements. Experimental results show that both the proposed division and square root circuits achieve lower mean squared errors (MSEs) while requiring nearly the same hardware resources, compared with the state‐of‐the‐art designs. This result shows the potential in exploiting signal correlation in SC circuit design for high accuracy. [ABSTRACT FROM AUTHOR]

Near infrared (NIR) light excitable photosensitizers are highly desirable for photodynamic therapy with deep penetration. Herein, a NIR‐II light (1200 nm) activated photosensitizer TQ‐BTPE is designed with aggregation‐induced singlet oxygen (1O2) generation for two‐photon photodynamic cancer cell ablation. TQ‐BTPE shows good two‐photon absorption and bright aggregation‐induced NIR‐I emission upon NIR‐II laser excitation. The 1O2 produced by TQ‐BTPE in an aqueous medium is much more efficient than that of commercial photosensitizer Ce6 under white light irradiation. Upon NIR‐II excitation, the two‐photon photosensitization of TQ‐BTPE is sevenfold higher than that of Ce6. The TQ‐BTPE molecules internalized by HeLa cells are mostly located in lysosomes as small aggregate dots with homogeneous distribution inside the cells, which favors efficient photodynamic cell ablation. The two‐photon photosensitization of TQ‐BTPE upon NIR‐I and NIR‐II excitation shows higher 1O2 generation efficiency than under NIR‐I excitation owing to the larger two‐photon absorption cross section at 920 nm. However, NIR‐II light exhibits better biological tissue penetration capability after passing through a fresh pork tissue, which facilitates stronger two‐photon photosensitization and better cancer cell ablation performance. This work highlights the promise of NIR‐II light excitable photosensitizers for deep‐tissue photodynamic therapy. [ABSTRACT FROM AUTHOR]

A novel visible‐light‐induced radical cascade trifluoromethylation/cyclization of N‐benzamides with CF3SO2Na has been achieved. This protocol provides an efficient strategy for the synthesis of CF3‐containing isoquinoline‐1,3‐diones under mild reaction conditions. The reaction features metal‐free, air oxidation, CF3SO2Na as CF3 source, additives free and operational simplicity. Moreover, the representative products displayed significant potencial antifungal activities in vitro. [ABSTRACT FROM AUTHOR]

Abstract: Red/near‐infrared dyes are highly demanded for biological applications but most of them are far from satisfactory. In this work, a series of red/near‐infrared fluorophores based on electron‐withdrawing benzo[1,2‐b:4,5‐b′]dithiophene 1,1,5,5‐tetraoxide (BDTO) are synthesized and characterized. They possess both aggregation‐induced emission, and hybridized local and charge‐transfer characteristics. Crystallographic, spectroscopic, electrochemical and computational results reveal that the oxidation of benzo[1,2‐b:4,5‐b′]dithiophene to BDTO can endow the fluorophores with greatly red‐shifted emission, enhanced emission efficiency, reduced energy levels, enlarged two‐photon absorption cross section, and increased reactive oxygen species generation efficiency. The nanoparticles fabricated with a near‐infrared fluorophore TPA‐BDTO show high photostability and biocompatibility with good performance in targeted photodynamic ablation of cancer cells and two‐photon fluorescence imaging of intravital mouse brain vasculature. [ABSTRACT FROM AUTHOR]

During the evolution of a software system, a large number of bug reports are submitted. Locating the source code files that need to be fixed to resolve the bugs is a challenging problem. Thus, there is a need for a technique that can automatically figure out these buggy files. A number of bug localization solutions that take in a bug report and output a ranked list of files sorted based on their likelihood to be buggy have been proposed in the literature. However, the accuracy of these tools still needs to be improved. In this paper, to address this need, we propose AmaLgam+, which is a method for locating relevant buggy files that puts together fives sources of information, namely, version history, similar reports, structure, stack traces, and reporter information. We perform a large-scale experiment on four open source projects, namely, AspectJ, Eclipse, SWT, and ZXing to localize more than 3000 bugs. We compare AmaLgam + with several state-of-the-art approaches including AmaLgam, BLUiR+, BRtracer+, BugLocator, and TFIDF-DHbPd. These approaches leverage one or several of the sources of information analyzed by AmaLgam+, but not all of them. On average, AmaLgam + achieves a 6.0% improvement over AmaLgam, which merges three sources of information, in terms of Mean Average Precision (MAP). For AspectJ and Eclipse datasets, in which there are many bug reports with stack traces and many reporters submit multiple bug reports, AmaLgam + achieves a 12.0% improvement over AmaLgam in terms of MAP. Compared with the other state-of-the-art approaches, AmaLgam + achieves an improvement of 20.3%, 22.5%, 33.1%, and 73.9% over BLUiR+, BRtracer+, BugLocator, and TFIDF-DHbPd in terms of MAP, respectively. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

SUMMARY Considering the effect of non-Darcy flow, the perturbation theory and normal mode method are introduced to analyze the linear stability of one-dimensional non-Darcy flow of gases in broken rocks. A stability criterion for linear systems is obtained theoretically when the steady states of pressure and velocity fields are perturbed, and the effects of the physical parameters on the linear governing system are studied theoretically and numerically. It is pointed out that the deviation coefficient from Darcy's law plays an important role in the governing system; the increasing absolute value of deviation coefficient from Darcy's law stabilizes the system, and the numerical results are shown graphically. Copyright © 2015 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Objective. To determine if supplemental intraarticular α2-macroglobulin (α2M) has a chondroprotective effect in a rat model of osteoarthritis (OA). Methods. Using Western blotting, mass spectrometry, enzyme-linked immunosorbent assay (ELISA), and immunohistochemistry, α2M was identified as a potential therapeutic agent through a comparison of α2M concentrations in serum, synovial fluid (SF), and cartilage from normal subjects and patients with OA. In cultured chondrocytes, the effects of α2M on interleukin-1 (IL-1)-induced cartilage catabolic enzymes were evaluated by Luminex assay and ELISA. In vivo effects on cartilage degeneration and matrix metalloproteinase 13 (MMP-13) concentration were evaluated in male rats (n =120) randomized to 1 of 4 treatments: 1) anterior cruciate ligament transection (ACLT) and saline injections, 2) ACLT and 1 IU/kg injections of α2M, 3) ACLT and 2 IU/kg injections of α2M, or 4) sham operation and saline injections. Rats were administered intraarticular injections for 6 weeks. The concentration of MMP-13 in SF lavage fluid was measured using ELISA. OA-related gene expression was quantified by real-time quantitative polymerase chain reaction. The extent of OA progression was graded by histologic examination. Results. In both normal subjects and OA patients, α2M levels were lower in SF as compared to serum, and in OA patients, MMP-13 levels were higher in SF than in serum. In vitro, α2M inhibited the induction of MMP-13 by IL-1 in a dose-dependent manner in human chondrocytes. In the rat model of ACLT OA, supplemental intraarticular injection of α2M reduced the concentration of MMP-13 in SF, had a favorable effect on OA-related gene expression, and attenuated OA progression. Conclusion. The plasma protease inhibitor α2M is not present in sufficient concentrations to inactivate the high concentrations of catabolic factors found in OA SF. Our findings suggest that supplemental intraarticular α2M provides chondral protection in posttraumatic OA. [ABSTRACT FROM AUTHOR]

SUMMARY In this paper, we study the adaptive resource allocation in multiuser orthogonal frequency division multiplexing (OFDM) systems. We try to maximize the sum capacity of an OFDM system with given transmission power budget, while meeting users' minimal rate requirements. Unlike other resource allocation schemes, which generally separate subchannel allocation and power distribution into independent procedures, our proposed algorithm implements joint subchannel and power allocation. Given a set of subchannels, the required power to satisfy a user's minimal rate constraint is calculated by water-filling policy. Then, the user who requires the maximum power to meet the rate requirement has a priority to obtain an additional subchannel. The procedure continues until all subchannels are consumed, by which time the consumed power to meet all users' rate requirements is also worked out. Finally, the margin power is allocated among all subchannels in an optimal manner to maximize the sum capacity of the OFDM system. Simulation results show that our proposed algorithm performs better than other existing ones. The solution produced by our proposed algorithm is close to the upper bound, while its complexity is relatively lower compared with other methods, which makes it attractive for applications. Copyright © 2012 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

SUMMARY In this paper we study the resource allocation problem for the multiuser orthogonal frequency division multiplexing (OFDM)-based cognitive radio (CR) systems with proportional rate constraints. The mutual interference introduced by primary user (PU) and cognitive radio user (also referred to secondary user, SU) makes the optimization problem of CR systems more complex. Moreover, the interference introduced to PUs must be kept under a given threshold. In this paper, the highest achievable rate of each OFDM subchannel is calculated by jointly considering the channel gain and interference level. First, a subchannel is assigned to the SU with the highest achievable rate. The remaining subchannels are always allocated to the SU that suffers the severest unjustness. Second, an efficient bit allocation algorithm is developed to maximize the sum capacity, which is again based on the highest achievable rate of each subchannel. Finally, an adjustment procedure is designed to maintain proportional fairness. Simulation results show that the proposed algorithm maximizes the sum capacity while keeping the proportional rate constraints satisfied. The algorithm exhibits a good tradeoff between sum capacity maximization and proportional fairness. Furthermore, the proposed algorithm has lower complexity compared with other algorithms, rendering it promising for practical applications. Copyright © 2011 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Image binarization algorithms in document image analysis divide pixel values into two groups, including white as background and black as foreground. Among others, the local contrast and mean (LCM)‐based thresholding algorithm offers excellent performance in processing degraded documents. This algorithm, however, is susceptible to noise and requires significant hardware resources. In this paper, an energy‐efficient and fault‐tolerant architecture is proposed for implementing the LCM algorithm in stochastic computing (SC). Leveraging correlated input bitstreams, this architecture saves energy and improves the fault tolerance of the implementation. Experimental results show that the proposed LCM stochastic architecture significantly outperforms the stochastic implementation of the Sauvola algorithm in terms of both binarization accuracy and hardware overhead and energy consumption. Even using 16‐bit streams, the proposed circuit produces an error rate lower than 5%. The stochastic implementation of the LCM algorithm using a 16‐bit length FSM‐based LD sequence is 22 times less in area, 26 times less in total power, 28 times less in energy consumption and more fault‐tolerant than the conventional 8‐bit bit‐width weighted binary with the same frequency constraints. [ABSTRACT FROM AUTHOR]

Developing stretchable strain sensors with high sensitivity and stability is crucial for various applications such as prosthetic hands, human health monitoring, and human‐machine interactions. However, achieving these qualities simultaneously remains challenging. Here, an inherently stretchable strain sensor is presented that integrates ultrahigh sensitivity and robust stability, enabling stretch, press, or bend sensing capabilities. This sensor employs a softer elastomeric channel filled with liquid metal (LM) as the conductive path. A stiffer elastomer convex integrated into the channel serves as a strain‐manipulated gate, controlling opening gap of electrical current flow path. During deformation, the softer elastomer undergoes cross sectional reduction due to the Poisson effect, while the stiffer convex gate retains its geometry. This heterogeneous deformation behavior leads to significant contraction or closure of the LM channel, resulting in increased resistance and a remarkable enhancement in sensitivity by more than two orders of magnitude. The all‐soft design maintains exceptional stability even under extended or repetitive substantial deformations. With the ability to monitor subtle and large human body movements, detect grip actions of soft grippers reliably, and monitor the gradual and extended growth process of plants, this sensor holds significant potential for advancements in flexible electronics. [ABSTRACT FROM AUTHOR]

The on‐chip near‐infrared (NIR) lasing devices based on van der Waals (vdW) layered materials are highly desired owing to their widespread applications in optoelectronic communication, computing, and sensing. However, the single‐mode NIR lasing devices with superior performance based on vdW layered materials are hard to obtain because of complex and meticulous microcavity structure and the damage to layered materials during preparation. Here, a high‐quality NIR single‐mode lasing device in γ‐phase indium selenide (γ‐InSe) is achieved by using a transferrable planar microcavity. The single‐mode lasing devices based on distributed Bragg reflectors microcavity and super Tamm structure can be simply prepared with quality factors up to 5710 and 3526, respectively. And angle‐resolved spectra show that the lasing device has high directionality with divergence angle <5°. Moreover, the wavelength of lasing device can be tuned ≈30 nm by varying the cavity length via thickness control of γ‐InSe layer. These results not only suggest that γ‐InSe is a promising material for NIR lasing devices, but also present a simple and effective approach for preparing high‐quality lasing devices utilizing other vdW layered materials. [ABSTRACT FROM AUTHOR]

Mitochondrial dysfunction and myocardial remodeling have been reported to be the main underlying molecular mechanisms of doxorubicin‐induced cardiotoxicity. SIRT6 is a nicotinamide adenine dinucleotide‐dependent enzyme that plays a vital role in cardiac protection against various stresses. Moreover, previous studies have demonstrated that FSTL1 could alleviate doxorubicin‐induced cardiotoxicity by inhibiting autophagy. The present study investigated the probable mechanisms of FSTL1 on doxorubicin‐induced cardiotoxicity in vivo and in vitro. We confirmed that FSTL1 exerted a pivotal protective role on cardiac tissue in vivo and on doxorubicin‐induced cell injury in vitro. Furthermore, FSTL1 can alleviate doxorubicin‐induced mitochondrial dysfunction by inhibiting autophagy and apoptosis. Further studies demonstrated that FSTL1 can activate SIRT6 signaling by restoring the SIRT6 protein expression in doxorubicin‐induced myocardial injury. SIRT6 activation elevated the protein expression of Nrf2 in doxorubicin‐induced H9C2 injury. Treatment with the Nrf2 inhibitor ML385 partially antagonized the cardioprotective role of SIRT6 on doxorubicin‐induced autophagy or apoptosis. These results suggested that the protective mechanism of FSTL1 on doxorubicin‐induced cardiotoxicity may be related with the inhibition of autophagy and apoptosis, partly through the activation of SIRT6/Nrf2. [ABSTRACT FROM AUTHOR]

Two‐photon fluorescence imaging allows in vivo study of biological structures and activities in deep tissues, in which bright fluorophores with high photostability and good biocompatibility are highly desirable. Herein, a small‐molecule fluorogen with aggregation‐induced emission (AIEgen) is complexed with fetal bovine serum (FBS) proteins to develop a protein‐sized AIEgen–protein hybrid nanocomposite (TPEPy‐FBS) with bright far‐red/near‐infrared (NIR) emission, excellent photostability, and low phototoxicity for deep and high‐resolution in vivo two‐photon brain vasculature imaging. Upon complexation with FBS, the fluorescence of TPEPy is greatly intensified and a sixfold enhancement is observed with 10% FBS in aqueous media. The yielded TPEPy‐FBS shows good physical stability in aqueous media and the phototoxicity of TPEPy is dramatically inhibited after complexation with FBS. Moreover, TPEPy‐FBS exhibits bright two‐photon fluorescence in far‐red/NIR region and good photostability upon femtosecond laser excitation, which facilitates high performance in vivo imaging. A large imaging depth of 656 µm is obtained in brain vasculature network imaging with a high signal‐to‐background ratio of 234, where a small blood capillary of 1.05 µm can be resolved at an imaging depth of 656 µm. Highlighted is a simple and versatile strategy to develop efficient two‐photon probes for in vivo biological imaging. [ABSTRACT FROM AUTHOR]

Perfect absorbers with extremely high absorption are of crucial importance for many applications such as harvesting solar energy and eliminating stray light. A key point for their applications is ultralow photon escaping rate (PER) with easy fabrication process, which enables to maximize energy utilization or minimize the influence of stray light. An ultrathin perfect absorber (total thickness of 226 nm) is reported in this work with dielectric plasmonic nanocomposite (titanium nitride (TiN) embedded in aluminum nitride (AlN)) and antireflective coating (ARC). It can be fabricated by low‐cost one‐step sputtering approach in a very large area (200 × 200 mm2 for demonstration) on almost any substrates, including flexible polyethylene‐terephthalate. The average PER is only 0.4% in the whole visible range of 400–750 nm. As an example, the absorber is used in a laser scanning confocal microscope to eliminate the strong laser stray light and enhance the signal‐to‐noise ratio, which improves the clarity and contrast of imaging remarkably. It can not only match the requirement of harvesting solar energy, but also is suitable for stray light elimination of weak signal detection instruments, etc. [ABSTRACT FROM AUTHOR]

In article number 1808365, Bin Liu and co‐workers report NIR‐II light (1200 nm) excitable single‐chain conjugated polymer dots with bright NIR‐I emission (peak at ≈725 nm and quantum yield of 20.6%) for deep in vivo two‐photon imaging of an intact brain. High contrast images clearly reveal brain vasculature structure through the intact skull with a large depth of 400 μm. [ABSTRACT FROM AUTHOR]

Methods for noninvasive brain imaging are highly desirable to study brain structures in neuroscience. Two‐photon fluorescence microscopy (2PFM) with near‐infrared (NIR) light excitation is a relatively noninvasive approach commonly used to study brain with high spatial resolution and large imaging depth. However, most of the current studies require cranial window implantation or skull‐thinning methods due to attenuation of excitation light. 2PFM through intact mouse skull is challenging due to strong scattering induced by skull bone. Herein, NIR‐II light excitable single‐chain conjugated polymer dots (CPdots) with bright fluorescence in NIR‐I region (peak at ≈725 nm and quantum yield of 20.6 ± 1.0%) are developed for deep in vivo two‐photon fluorescence (2PF) imaging of intact mouse brain. The synthesized CPdots exhibit good biocompatibility, high photostability, and large two‐photon absorption cross section. The CPdots allow 2PF images acquired upon excitation at 800, 1040 and 1200 nm with the highest signal‐to‐background ratio of 208 demonstrated for 1200 nm excitation. Moreover, a 3D reconstruction of the brain blood vessel network is obtained with a large vertical depth of 400 µm through intact skull. This work demonstrates great potential of bright NIR fluorophores for in vivo deep tissue imaging. NIR‐II light (1200 nm) excitable single‐chain conjugated polymer dots with bright NIR‐I emission (peak at ≈725 nm and quantum yield of 20.6%) is developed for deep in vivo two‐photon imaging of intact mouse brain. High contrast images clearly reveal brain vasculature structure through intact skull with a large depth of 400 µm. [ABSTRACT FROM AUTHOR]

Because the energy consumption is growing rapidly, green radio, which lays emphasis on the energy efficiency (EE) in wireless networks, is becoming increasingly important. As potential paradigms for future wireless network design, cognitive radio (CR) is a promising technology to solve the spectrum shortage and inefficiency issues, while cooperative relay is capable of improving spectral efficiency by combating severe fading in wireless environment. In this paper, we investigate the energy-efficient power allocation problem in orthogonal frequency division multiplexing (OFDM)-based relaying CR networks. We develop a general framework to maximize the overall EE of the CR system, under the constraints of transmission power budget, traffic demands, and the interference constraints of the primary users. Our problem formulation is a nonconvex optimization task, and it is hard to obtain the optimal solution. We first convert our formulated problem into a convex optimization problem via its hypograph form, which can be solved by the barrier method. Then we further speed up the computation of Newton step during the barrier method, significantly reducing the complexity of the algorithm by exploiting its special structure. Numerical results validate that our method can exploit the overall EE of CR systems, while the algorithm converges efficiently and stably. Copyright © 2015 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Mid‐infrared (MIR) semiconductor laser sources are essential for applications in gas detection, infrared imaging, and high‐speed free space optical communications. At present, the dynamic wavelength tunability of MIR lasers based on lead salt, antimonide, and quantum cascade lasers is limited and their compact size as well as heterogeneous integration are still challenging. Two‐dimensional (2D) materials, used as optical gain materials, have the flexible tunability and compatible van der Waals integrations—providing many new possibilities for constructing MIR laser sources of large tunability and high integration. Here, wide‐wavelength tunable MIR vertical cavity surface emitting lasers (VCSELs) integrated on silicon substrates are realized based on 2D black arsenic phosphorus (b‐AsxP1−x). The emission wavelength of the optically pumped laser device is demonstrated to be tuned from 3.42 to 4.65 µm at room temperature, which could be controlled by adjusting the alloy composition and thickness of the gain media b‐AsxP1−x. The tunable MIR VCSEL device would pave the way for further exploration of 2D materials‐based IR lasers working as on‐chip light sources. [ABSTRACT FROM AUTHOR]

Integrated multiwavelength nanolasers are important in the practical development of optical circuitry for optical information processing and optical data storage. Herein, a new method for on‐chip integrated lasers is proposed, which can integrate single‐mode lasers with multiple wavelengths at room temperature. A four‐wavelength single‐mode nanoribbon laser chip is fabricated for demonstration. The mode of different laser units is controlled by the thickness of dielectric microcavity layers to select the resonant modes of excitation. Therefore, multiwavelength lasing can be coupled out based on the integrated cavity which is realized using combinatorial etching technique and can integrate tens of different‐wavelength lasers on a chip. The lasing modes of this device are all single‐mode lasing because of the short cavity length. Its lowest lasing threshold is only 5.4 kW cm−2. The gain material and the dielectric microcavity can be controlled and fabricated separately, which have strong controllability and flexibility. This new laser chip paves the way for a new class of hybrid nanolasers for chip‐integrated applications. [ABSTRACT FROM AUTHOR]

Short‐wave infrared (SWIR) information is critical for material analysis, imaging sensing, and other fields. To acquire SWIR spectrum with compact devices, strategies for reconstructive microspectrometer have emerged, such as photonic crystal and quantum dot filter. However, the current SWIR microspectrometer needs many filters with insufficient resolution. In this work, the authors develop a SWIR chip‐spectrometer based on Fabry–Perot microcavities array which can be fabricated by using fast and low‐cost UV laser direct‐writing grayscale lithography. The ultra‐compact chip‐spectrometer can work in a very wide range from 900 to 1700 nm with only 20 detector pixels and a reconstruction algorithm. The spectral resolution achieves 2 nm by 50 pixels set and 5 nm by 20 pixels set at SWIR range, which is 3 times higher, with 3.9 times less units number, than for recently reported SWIR quantum dot spectrometers. To the best of our knowledge, this is a minimum high‐resolution SWIR InGaAs detector based chip‐spectrometer which can work in the whole SWIR band with only 20 detector pixels. It has great potential for applications in smart‐phone or other miniature portable spectrometers. [ABSTRACT FROM AUTHOR]

Inorganic perovskites have become a widely investigated candidate for fabrication of high‐performance micro‐devices due to their excellent optoelectronic properties and stability to the environment. Especially, their excellent lasing characteristics as a micro/nanolaser source, combined with flexible substrates, have great potential in the field of wearable or foldable photonic device applications. Here, the high‐quality CsPbBr3 perovskite microsheets with stress‐induced grooves are directly prepared on the ultrathin fluorine mica by the chemical vapor deposition method, and the single‐mode lasers are realized in these large‐size (>15 × 15 µm) microsheets. Thanks to the flexibility of mica, bending induced tensile strain on CsPbBr3 microsheet causes the laser mode blueshift continuously and reversibly with 15.3 meV %−1, this can be well explained by the Lorentz oscillator model under lasing conditions. Furthermore, by using the first‐principles calculation, it is clarified that the bandedge blueshift originates from the distortion of {PbBr6}4− octahedra and the consequential increase of the bond length of Pb‐Br3 and the Pb‐Br3‐Pb bond angle. This work opens up a new way to realize on‐chip single‐mode lasers with microstructures, and is helpful for the application of flexible photonic device in the fields of integrated on‐chip sensors. [ABSTRACT FROM AUTHOR]

Nanocrystals (NCs) are widely used in optoelectronics, photocatalysis, and bioimaging. As the surface area to volume ratio increases with a decrease in the size of NCs, strategies to control the size of NCs are highly valuable for many applications. Given the importance of photoluminescent dyes, especially those with aggregation‐induced emission, the transformation from an amorphous to a crystalline state can yield a drastic enhancement in their optical properties, which is of significance for biomedical applications. Till now, there is no general method available for the synthesis of small NCs with accurate control over the size and uniformity. Herein, a simple and general approach of ouzo nanocrystallization is presented for the synthesis of small (<100 nm) and highly uniform (polydispersity index~0.1) NCs with good control over the size. The process of nanoprecipitation is used to synthesize uniform nanoparticles (NPs) with different size, which is followed by solvent addition to form swollen NPs. Further, the amorphous core of swollen NPs is converted into NCs within polymer shell under Ouzo zone, which restricts NCs to grow above certain size. To demonstrate the general applicability of ouzo nanocrystallization, two different classes of luminescent materials are used as examples to fabricate small and highly uniform NCs. [ABSTRACT FROM AUTHOR]

The direct growth of semiconductor nanowire (NW) arrays horizontally aligned on a substrate is critically important for the applications of NWs in electronic or optoelectronic devices at the circuit level. The strict requirement of lattice matching between a substrate and a material in the covalent epitaxy of crystals makes the wire arrays be grown on the substrates only with similar lattice parameters. Herein, a van der Waals epitaxy route is developed to realize the in‐plane growth of large‐scale Bi2S3 NW arrays on mica with a large lattice mismatch. The orthorhombic Bi2S3 NWs grow epitaxially with the axial direction of ⟨001⟩Bi2S3 along the six symmetric directions of the mica. Transmission electron microscope measurements show that the epitaxial relationships are [001]Bi2S3||[100]mica and [32¯0]Bi2S3||[010]mica along the length and width directions of the wires, respectively. More importantly, photodetectors based on Bi2S3 NWs show a wide photoresponse spectrum range from 500 to 980 nm. A high responsivity (5233 A W−1) and a specific detectivity (1.8 × 1012 Jones) are achieved under 830 nm light irradiation with ultralow intensity (64 nW cm−2). In addition, the photodetectors exhibit high stability with at least 48 day storage in ambient atmosphere or with 1000 times bending. [ABSTRACT FROM AUTHOR]

On-Chip Multiwavelength Single-Mode Lasers with CdSe Nanoribbons-Embedded Microcavities B Single-Mode Lasers b In article number 2200367, Shaowei Wang and co-workers propose on-chip multi-wavelength single-mode lasers with CdSe nanoribbons embedded in microcavities. The number and wavelength of integrated lasers can be easily controlled by the thickness of the microcavities. [Extracted from the article]