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1.
Nat Mater ; 23(7): 928-936, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38777873

RESUMO

Controlling topological phases of light allows the observation of abundant topological phenomena and the development of robust photonic devices. The prospect of more sophisticated control with topological photonic devices for practical implementations requires high-level programmability. Here we demonstrate a fully programmable topological photonic chip with large-scale integration of silicon photonic nanocircuits and microresonators. Photonic artificial atoms and their interactions in our compound system can be individually addressed and controlled, allowing the arbitrary adjustment of structural parameters and geometrical configurations for the observation of dynamic topological phase transitions and diverse photonic topological insulators. Individual programming of artificial atoms on the generic chip enables the comprehensive statistical characterization of topological robustness against relatively weak disorders, and counterintuitive topological Anderson phase transitions induced by strong disorders. This generic topological photonic chip can be rapidly reprogrammed to implement multifunctionalities, providing a flexible and versatile platform for applications across fundamental science and topological technologies.

2.
Nano Lett ; 24(9): 2931-2938, 2024 Mar 06.
Artigo em Inglês | MEDLINE | ID: mdl-38377049

RESUMO

Plasmon-induced hot-electron transfer at the metallic nanoparticle/semiconductor interface is the basis of plasmon-enhanced photocatalysis and energy harvesting. However, limited by the nanoscale size of hot spots and femtosecond time scale of hot-electron transfer, direct observation is still challenging. Herein, by using spatiotemporal-resolved photoemission electron microscopy with a two-color pump-probe beamline, we directly observed such a process with a concise system, the Au nanoparticle/monolayer transition-metal dichalcogenide (TMD) interface. The ultrafast hot-electron transfer from Au nanoparticles to monolayer TMDs and the plasmon-enhanced transfer process were directly measured and verified through an in situ comparison with the Au film/TMD interface and free TMDs. The lifetime at the Au nanoparticle/MoSe2 interface decreased from 410 to 42 fs, while the photoemission intensities exhibited a 27-fold increase compared to free MoSe2. We also measured the evolution of hot electrons in the energy distributions, indicating the hot-electron injection and decay happened in an ultrafast time scale of ∼50 fs without observable electron cooling.

3.
J Transl Med ; 22(1): 365, 2024 Apr 17.
Artigo em Inglês | MEDLINE | ID: mdl-38632658

RESUMO

BACKGROUND: Molecular subtyping is expected to enable precise treatment. However, reliable subtyping strategies for clinical application remains defective and controversial. Given the significance of tumor immune dysfunction and exclusion (TIDE), we aimed to develop a novel TIDE-based subtyping strategy to guide personalized immunotherapy in the bladder cancer (BC). METHODS: Transcriptome data of BC was used to evaluate the heterogeneity and the status of TIDE patterns. Subsequently, consensus clustering was applied to classify BC patients based on TIDE marker-genes. Patients' clinicopathological, molecular features and signaling pathways of the different TIDE subtypes were well characterized. We also utilize the deconvolution algorithms to analyze the tumor microenvironment, and further explore the sensitivity and mechanisms of each subtype to immunotherapy. Furthermore, BC patient clinical information, real-world BC samples and urine samples were collected for the validation of our findings, which were used for RNA-seq analysis, H&E staining, immunohistochemistry and immunofluorescence staining, and enzyme-linked immunosorbent assay. Finally, we also explored the conservation of our novel TIDE subtypes in pan-cancers. RESULTS: We identified 69 TIDE biomarker genes and classified BC samples into three subtypes using consensus clustering. Subtype I showed the lowest TIDE status and malignancy with the best prognosis and highest sensitivity to immune checkpoint blockade (ICB) treatment, which was enriched of metabolic related signaling pathways. Subtype III represented the highest TIDE status and malignancy with the poorest prognosis and resistance to ICB treatment, resulting from its inhibitory immune microenvironment and T cell terminal exhaustion. Subtype II was in a transitional state with intermediate TIDE level, malignancy, and prognosis. We further confirmed the existence and characteristics of our novel TIDE subtypes using real-world BC samples and collected patient clinical data. This subtyping method was proved to be more efficient than previous known methods in identifying non-responders to immunotherapy. We also propose that combining our TIDE subtypes with known biomarkers can potentially improve the sensitivity and specificity of these biomarkers. Moreover, besides guiding ICB treatment, this classification approach can assist in selecting the frontline or recommended drugs. Finally, we confirmed that the TIDE subtypes are conserved across the pan-tumors. CONCLUSIONS: Our novel TIDE-based subtyping method can serve as a powerful clinical tool for BC and pan-cancer patients, and potentially guiding personalized therapy decisions for selecting potential beneficiaries and excluding resistant patients of ICB therapy.


Assuntos
Neoplasias da Bexiga Urinária , Humanos , Imunoterapia , Biomarcadores Tumorais , Algoritmos , Análise por Conglomerados , Microambiente Tumoral , Prognóstico
4.
Phys Rev Lett ; 132(24): 243802, 2024 Jun 14.
Artigo em Inglês | MEDLINE | ID: mdl-38949371

RESUMO

Orbital angular momentum (OAM) provides an additional degree of freedom for optical communication systems, and manipulating on-chip OAM is important in integrated photonics. However, there is no effective method to realize OAM topological charge conversion on chip. In this Letter, we propose a way to convert OAM by encircling two groups of exceptional points in different Riemann sheets. In our framework, any OAM conversion can be achieved on demand just by manipulating adiabatic and nonadiabatic evolution of modes in two on-chip waveguides. More importantly, the chiral OAM conversion is realized, which is of great significance since the path direction can determine the final topological charge order. Our Letter presents a special chiral behavior and provides a new method to manipulate OAM on the chip.

5.
World J Urol ; 42(1): 88, 2024 Feb 19.
Artigo em Inglês | MEDLINE | ID: mdl-38372802

RESUMO

PURPOSE: To compare the diagnostic ability of traditional radiographic urethrography and magnetic resonance urethrography (MRU) for iatrogenic bladder outlet obliteration (BOO), and explore the efficacy and complications of laparoscopic modified Y-V plasty for patients selected based on MRU evaluation. METHODS: 31 patients with obliteration segments ≤ 2 cm and no false passages or diverticula based on MRU evaluation from eight centers in China were included. Obliteration segments were measured preoperatively by MRU and conventional RUG/VCUG and compared with intra-operative measurements. Surgical effects were evaluated by uroflow rates, urethrography, or cystoscopy at 1, 3, 6, and 12 months post-operation and then every 12 months. Postoperative urinary continence was assessed by 24-h urine leakage (g/day). RESULTS: The results showed that MRU measured the length of obliteration more accurately than RUG/VCUG (MRU 0.91 ± 0.23 cm, RUG/VCUG 1.72 ± 1.08 cm, Actual length 0.96 ± 0.36 cm, p < 0.001), and clearly detected false passages and diverticula. Laparoscopic Y-V plasty was modified by incisions at 5 and 7 o'clock positions and double-layer suture with barbed sutures. All operations were successfully completed within a median time of 75 (62-192) minutes and without any complications. Urethral patency and urinary continence rates were 90.3% (28/31) and 87.1% (27/31), respectively. Three recurrences were cured by direct visual internal urethrotomy. Four patients had stress urinary incontinence after catheter removal 14 days post-operation, with urine leakage of 80-120 g/day, not relieved during follow-up. CONCLUSIONS: Laparoscopic modified Y-V plasty based on MRU evaluation is a promising approach for iatrogenic BOO, with a high patency rate and a low incontinence rate.


Assuntos
Divertículo , Bexiga Urinária , Humanos , China , Divertículo/cirurgia , Espectroscopia de Ressonância Magnética , Doença Iatrogênica
6.
BMC Urol ; 24(1): 99, 2024 Apr 30.
Artigo em Inglês | MEDLINE | ID: mdl-38685008

RESUMO

OBJECTIVE: To evaluate the efficacy of urethral-sparing laparoscopic simple prostatectomy (US-LSP) for the treatment of large-volume (>80 ml) benign prostatic hyperplasia (BPH) with asymptomatic urethral stricture (urethral lumen > 16 Fr) after urethral stricture surgery. METHODS: We retrospectively analyzed clinical data of 39 large-volume BPH patients with asymptomatic urethral stricture after urethral stricture surgery who underwent US-LSP from January 2016 to October 2021. Postoperative follow-ups were scheduled at 1, 3, and 6 months. RESULTS: All patients affected by significant BPH-related lower urinary tract symptoms (LUTS) including 22 cases with asymptomatic anterior urethral stricture and 17 cases with asymptomatic posterior urethral stricture. Median operative time was 118 min (interquartile range [IQR]100-145). Median estimated blood loss was 224 ml (IQR: 190-255). 33 patients(84.6%) avoided continuous bladder irrigation. Postoperative complications occurred in 5 patients (12.8%), including 4 cases with Clavien-Dindo grade 1 and grade 2 and 1 case with grade 3a. During follow-up, US-LSP presented statistically significant improvements in LUTS compared to baseline (P < 0.05). A total of 25 patients had normal ejaculation preoperatively and 3 patients (12%) complained retrograde ejaculation postoperatively. Two patients (5.1%) reported stress urinary incontinence (SUI) and no patient reported aggravated urethral stricture during follow-up. CONCLUSIONS: US-LSP was safe and effective in treating large-volume BPH with asymptomatic urethral stricture after urethral stricture surgery. Meanwhile, US-LSP could reduce the risk of SUI in patients with asymptomatic posterior urethral stricture and maintain ejaculatory function in a high percentage of patients.


Assuntos
Laparoscopia , Prostatectomia , Hiperplasia Prostática , Estreitamento Uretral , Humanos , Masculino , Hiperplasia Prostática/cirurgia , Hiperplasia Prostática/complicações , Estudos Retrospectivos , Estreitamento Uretral/etiologia , Estreitamento Uretral/cirurgia , Idoso , Prostatectomia/métodos , Prostatectomia/efeitos adversos , Tratamentos com Preservação do Órgão/métodos , Pessoa de Meia-Idade , Doenças Assintomáticas , Uretra/cirurgia , Resultado do Tratamento , Complicações Pós-Operatórias/etiologia
7.
Nano Lett ; 23(20): 9547-9554, 2023 Oct 25.
Artigo em Inglês | MEDLINE | ID: mdl-37816225

RESUMO

Exploring ultrafast carrier dynamics is crucial for the materials' fundamental properties and device design. In this work, we employ time- and energy-resolved photoemission electron microscopy with tunable pump wavelengths from visible to near-infrared to reveal the ultrafast carrier dynamics of the elemental semiconductor tellurium. We find that two discrete sub-bands around the Γ point of the conduction band are involved in excited-state electron ultrafast relaxation and reveal that hot electrons first go through ultrafast intra sub-band cooling on a time scale of about 0.3 ps and then transfer from the higher sub-band to the lower one on a time scale of approximately 1 ps. Additionally, theoretical calculations reveal that the lower one has flat-band characteristics, possessing a large density of states and a long electron lifetime. Our work demonstrates that TR- and ER-PEEM with broad tunable pump wavelengths are powerful techniques in revealing the details of ultrafast carrier dynamics in time and energy domains.

8.
J Transl Med ; 21(1): 789, 2023 11 07.
Artigo em Inglês | MEDLINE | ID: mdl-37936202

RESUMO

BACKGROUND: Prostate cancer (PCA) is the fifth leading cause of cancer-related deaths worldwide, with limited treatment options in the advanced stages. The immunosuppressive tumor microenvironment (TME) of PCA results in lower sensitivity to immunotherapy. Although molecular subtyping is expected to offer important clues for precision treatment of PCA, there is currently a shortage of dependable and effective molecular typing methods available for clinical practice. Therefore, we aim to propose a novel stemness-based classification approach to guide personalized clinical treatments, including immunotherapy. METHODS: An integrative multi-omics analysis of PCA was performed to evaluate stemness-level heterogeneities. Unsupervised hierarchical clustering was used to classify PCAs based on stemness signature genes. To make stemness-based patient classification more clinically applicable, a stemness subtype predictor was jointly developed by using four PCA datasets and 76 machine learning algorithms. RESULTS: We identified stemness signatures of PCA comprising 18 signaling pathways, by which we classified PCA samples into three stemness subtypes via unsupervised hierarchical clustering: low stemness (LS), medium stemness (MS), and high stemness (HS) subtypes. HS patients are sensitive to androgen deprivation therapy, taxanes, and immunotherapy and have the highest stemness, malignancy, tumor mutation load (TMB) levels, worst prognosis, and immunosuppression. LS patients are sensitive to platinum-based chemotherapy but resistant to immunotherapy and have the lowest stemness, malignancy, and TMB levels, best prognosis, and the highest immune infiltration. MS patients represent an intermediate status of stemness, malignancy, and TMB levels with a moderate prognosis. We further demonstrated that these three stemness subtypes are conserved across pan-tumor. Additionally, the 9-gene stemness subtype predictor we developed has a comparable capability to 18 signaling pathways to make tumor diagnosis and to predict tumor recurrence, metastasis, progression, prognosis, and efficacy of different treatments. CONCLUSIONS: The three stemness subtypes we identified have the potential to be a powerful tool for clinical tumor molecular classification in PCA and pan-cancer, and to guide the selection of immunotherapy or other sensitive treatments for tumor patients.


Assuntos
Neoplasias da Próstata , Masculino , Humanos , Neoplasias da Próstata/genética , Neoplasias da Próstata/terapia , Prognóstico , Antagonistas de Androgênios , Multiômica , Recidiva Local de Neoplasia , Imunoterapia , Microambiente Tumoral
9.
J Appl Microbiol ; 134(4)2023 Apr 03.
Artigo em Inglês | MEDLINE | ID: mdl-37081765

RESUMO

AIMS: The present study aimed to isolate a potential antagonist Bacillus sp. and evaluate its capacity for controlling pathogenic Vibrio parahaemolyticus in aquaculture. METHODS AND RESULTS: Strain JK08, which showed inhibitory activity against V. parahaemolyticus VP02r, was isolated from a Penaeus vannamei pond. Based on morphological, physiological, and biochemical characteristics and phylogenetic analysis, strain JK08 was identified as Bacillus sp. Through culture condition optimization, the maximal inhibition zone diameter (18.19 ± 0.16 mm) was observed when strain JK08 was cultivated at a temperature of 30°C, pH of 7, and salinity of 20‰ in Luria-Bertani broth for 24 h. The inhibition zone against V. parahaemolyticus VP02r of strain JK08 (∼7 µg, in mass of crude antimicrobial substance, per tablet) was larger than those (14-18 mm in diameter) of several commercial antibiotics (10 µg per tablet) in the in vitro antagonism assay. Liquid chromatography-tandem mass spectrometry analysis results indicated the presence of three families of lipopeptides in the antimicrobial substance: surfactin (C12-C17), iturin A (C14-C17), and fengycin A (C14-C17) and B (C17), which might be the key components contributing to the antagonistic activity of strain JK08. CONCLUSIONS: Strain JK08, which is capable of producing antibacterial lipopeptides, shows effective antagonistic activity against V. parahaemolyticus VP02r, implying its promising potential for V. parahaemolyticus control in aquaculture.


Assuntos
Bacillus , Vibrio parahaemolyticus , Filogenia , Antibacterianos/farmacologia , Lipopeptídeos/química
10.
J Am Chem Soc ; 144(4): 1700-1708, 2022 Feb 02.
Artigo em Inglês | MEDLINE | ID: mdl-35041406

RESUMO

The benefits of excess PbI2 on perovskite crystal nucleation and growth are countered by the photoinstability of interfacial PbI2 in perovskite solar cells (PSCs). Here we report a simple chemical polishing strategy to rip PbI2 crystals off the perovskite surface to decouple these two opposing effects. The chemical polishing results in a favorable perovskite surface exhibiting enhanced luminescence, prolonged carrier lifetimes, suppressed ion migration, and better energy level alignment. These desired benefits translate into increased photovoltages and fill factors, leading to high-performance mesostructured formamidinium lead iodide-based PSCs with a champion efficiency of 24.50%. As the interfacial ion migration paths and photodegradation triggers, dominated by PbI2 crystals, were eliminated, the hysteresis of the PSCs was suppressed and the device stability under illumination or humidity stress was significantly improved. Moreover, this new surface polishing strategy can be universally applicable to other typical perovskite compositions.

11.
Phys Rev Lett ; 129(5): 053903, 2022 Jul 29.
Artigo em Inglês | MEDLINE | ID: mdl-35960552

RESUMO

The gain and loss in photonic lattices provide possibilities for many functional phenomena. In this Letter, we consider photonic topological insulators with different types of gain-loss domain walls, which will break the translational symmetry of the lattices. A method is proposed to construct effective Hamiltonians, which accurately describe states and the corresponding energies at the domain walls for different types of photonic topological insulators and domain walls with arbitrary shapes. We also consider domain-induced higher-order topological states in two-dimensional non-Hermitian Aubry-André-Harper lattices and use our method to explain such phenomena successfully. Our results reveal the physics in photonic topological insulators with gain-loss domain walls, which provides advanced pathways for manipulation of non-Hermitian topological states in photonic systems.

12.
Cardiovasc Drugs Ther ; 36(3): 505-509, 2022 06.
Artigo em Inglês | MEDLINE | ID: mdl-33779938

RESUMO

BACKGROUND: Heart failure (HF) is one of the most serious health concerns worldwide. Anemia is a highly prevalent comorbidity and outcome predictor in HF patients. Sodium glucose co-transport 2 (SGLT2) inhibitors have been demonstrated to reduce the risk of cardiovascular death and HF hospitalization in HF patients. PURPOSE: This investigator-initiated, interventional, prospective, double-blind, multicenter study is designed to investigate whether anemia correction is one of the prerequisites and determinants related to the beneficial effects of dapagliflozin in HF patients. METHODS AND RESULTS: Up to 2030 HF participants receiving standard care will be randomly assigned to either oral dapagliflozin 10 mg once daily or placebo 10 mg once daily for 12 months. The primary outcome is the composite incidence of hospital admission for HF and all-cause death. Secondary outcomes include change in the Kansas City Cardiomyopathy Questionnaire (KCCQ) score and change in 6-min walk distance and hemoglobin level. Patients will be followed for 12 months after randomization. CONCLUSIONS: The ADIDAS trial offers an opportunity to assess the hemoglobin change and association between hemoglobin change and readmissions due to heart failure and all-cause death in patients with heart failure treated with dapagliflozin or placebo. This study could highlight if dynamic hemoglobin change is related to the outcome for HF patients. TRIAL REGISTRATION: ClinicalTrials.gov ; NCT04707261. Registration date, 2020/12/01, "retrospectively registered".


Assuntos
Anemia , Insuficiência Cardíaca , Anemia/diagnóstico , Anemia/tratamento farmacológico , Compostos Benzidrílicos , Glucosídeos , Insuficiência Cardíaca/diagnóstico , Insuficiência Cardíaca/tratamento farmacológico , Humanos , Estudos Prospectivos , Volume Sistólico
13.
Nano Lett ; 21(21): 9270-9278, 2021 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-34670093

RESUMO

Time-domain dynamic evolution properties of topological states play an important role in both fundamental physics study and practical applications of topological photonics. However, owing to the absence of available ultrafast time-domain dynamic characterization methods, studies have mostly focused on the frequency-domain-based properties, and there are few reports demonstrating the time-domain-based properties. Here, we measured the dynamic near-field responses of plasmonic topological structures of gold nanochains with the configuration of the Su-Schrieffer-Heeger model by using ultrahigh spatial-temporal resolution photoemission electron microscopy. The dephasing time of plasmonic topological edge states increases with increasing the bulk lattice number that has a threshold requirement and finally reaches saturation. We directly revealed through simulation that there is a transient bulk state in the evolution of topological edge states, that is, the energy undergoes relaxation from oscillation between the bulk lattice and the edge. This work shows a new perspective of time-domain dynamic topological photonics.

14.
Cell Biochem Funct ; 39(6): 740-753, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34165197

RESUMO

The freshwater crayfish is capable of regenerating limbs, following autotomy, injury and predation. In arthropod species, regeneration and moulting are two processes linked and strongly regulated by ecdysone. The regeneration of crayfish limbs is divided into wound healing, blastema formation, cellular reprogramming and tissue patterning. Limb blastema cells undergo proliferation, dedifferentiation and redifferentiation. A limb bud, containing folded segments of the regenerating limb, is encased within a cuticular sheath. The functional limb regenerates, in proecdysis, in two to three consecutive moults. Rapid tissue growth is regulated by hormones, limb nerves and local cells. The TGF-ß/activin signalling pathway has been determined in the crayfish, P. fallax f. virginalis, and is suggested as a potential regulator of tissue regeneration. In this review article, we discuss current understanding of tissue regeneration in the crayfish and various crustaceans. A thorough understanding of the cellular, genetic and molecular pathways of these biological processes is promising for the development of therapeutic applications for a wide array of diseases in regenerative medicine.


Assuntos
Extremidades/fisiologia , Água Doce , Regeneração , Animais , Astacoidea , Crustáceos
15.
Nano Lett ; 20(5): 3747-3753, 2020 May 13.
Artigo em Inglês | MEDLINE | ID: mdl-32242668

RESUMO

A comprehensive understanding of the ultrafast electron dynamics in two-dimensional transition metal dichalcogenides (TMDs) is necessary for their applications in optoelectronic devices. In this work, we contribute a study of ultrafast electron cooling and decay dynamics in the supported and suspended monolayer WS2 by time- and energy-resolved photoemission electron microscopy (PEEM). Electron cooling in the Q valley of the conduction band is clearly resolved in energy and time, on a time scale of 0.3 ps. Electron decay is mainly via a defect trapping process on a time scale of several picoseconds. We observed that the trap states can be produced and increased by laser illumination under an ultrahigh vacuum, and the higher local optical-field intensity led to the faster increase of trap states. The enhanced defect trapping could significantly modify the carrier dynamics and should be paid attention to in photoemission experiments for two-dimensional materials.

16.
Molecules ; 26(9)2021 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-34068710

RESUMO

Phase-change materials (PCMs) are important photonic materials that have the advantages of a rapid and reversible phase change, a great difference in the optical properties between the crystalline and amorphous states, scalability, and nonvolatility. With the constant development in the PCM platform and integration of multiple material platforms, more and more reconfigurable photonic devices and their dynamic regulation have been theoretically proposed and experimentally demonstrated, showing the great potential of PCMs in integrated photonic chips. Here, we review the recent developments in PCMs and discuss their potential for photonic devices. A universal overview of the mechanism of the phase transition and models of PCMs is presented. PCMs have injected new life into on-chip photonic integrated circuits, which generally contain an optical switch, an optical logical gate, and an optical modulator. Photonic neural networks based on PCMs are another interesting application of PCMs. Finally, the future development prospects and problems that need to be solved are discussed. PCMs are likely to have wide applications in future intelligent photonic systems.

17.
Phys Rev Lett ; 125(1): 013902, 2020 Jul 03.
Artigo em Inglês | MEDLINE | ID: mdl-32678635

RESUMO

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.

18.
Phys Rev Lett ; 124(16): 163901, 2020 Apr 24.
Artigo em Inglês | MEDLINE | ID: mdl-32383952

RESUMO

Near-field enhancement and dephasing time play critical roles in several applications of localized surface plasmon resonance. Here, using an example gold dimer system, we reveal the correlation between the near-field enhancement and dephasing time via time-resolved photoemission electron microscopy. Compared with isolated particles, dimers with small gap sizes show stronger near-field enhancement and shorter dephasing times. These results are well reproduced by numerical simulations and further explained by a coupled dipole approximation model. The roles of near- and far-field coupling and plasmon localization in balancing near-field enhancement and dephasing time are also unveiled.

19.
Opt Lett ; 44(23): 5772-5775, 2019 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-31774776

RESUMO

The nanoscale wavelength and polarization router, which can simultaneously separate wavelength and polarization modes, is an essential component of on-chip nanophotonic devices. Here, an on-chip wavelength and polarization router is realized experimentally based on a three-layer hybrid waveguide of Au-SiO2-LiNbO3 etched with asymmetric nano-cavities. The central area size of the device is only 1.60×1.96 µm2. A broad operation band covers from 500 nm to 1150 nm with low cross talk of under 10 dB. The monolithic-LiNbO3is introduced for the first time, to the best of our knowledge, to on-chip multichannel wavelength and polarization routers. This work plays a key role for dense chip integration, visible light displays, and communications, and can inspire LiNbO3-based nanophotonic devices.

20.
Small ; 14(9)2018 03.
Artigo em Inglês | MEDLINE | ID: mdl-29320610

RESUMO

Recently, organometal halide perovskite-based optoelectronics, particularly lasers, have attracted intensive attentions because of its outstanding spectral coherence, low threshold, and wideband tunability. In this work, high-quality CH3 NH3 PbBr3 single crystals with a unique shape of cube-corner pyramids are synthesized on mica substrates using chemical vapor deposition method. These micropyramids naturally form cube-corner cavities, which are eminent candidates for small-sized resonators and retroreflectors. The as-grown perovskites show strong emission ≈530 nm in the vertical direction at room temperature. A special Fabry-Pérot (F-P) mode is employed to interpret the light confinement in the cavity. Lasing from the perovskite pyramids is observed from 80 to 200 K, with threshold ranging from ≈92 µJ cm-2 to 2.2 mJ cm-2 , yielding a characteristic temperature of T0 = 35 K. By coating a thin layer of Ag film, the threshold is reduced from ≈92 to 26 µJ cm-2 , which is accompanied by room temperature lasing with a threshold of ≈75 µJ cm-2 . This work advocates the prospect of shape-engineered perovskite crystals toward developing micro-sized optoelectronic devices and potentially investigating light-matter coupling in quantum optics.

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