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1.
Comput Biol Med ; 178: 108709, 2024 Jun 06.
Artigo em Inglês | MEDLINE | ID: mdl-38878398

RESUMO

With the significant advancements of Large Language Models (LLMs) in the field of Natural Language Processing (NLP), the development of image-text multimodal models has garnered widespread attention. Current surveys on image-text multimodal models mainly focus on representative models or application domains, but lack a review on how general technical models influence the development of domain-specific models, which is crucial for domain researchers. Based on this, this paper first reviews the technological evolution of image-text multimodal models, from early explorations of feature space to visual language encoding structures, and then to the latest large model architectures. Next, from the perspective of technological evolution, we explain how the development of general image-text multimodal technologies promotes the progress of multimodal technologies in the biomedical field, as well as the importance and complexity of specific datasets in the biomedical domain. Then, centered on the tasks of image-text multimodal models, we analyze their common components and challenges. After that, we summarize the architecture, components, and data of general image-text multimodal models, and introduce the applications and improvements of image-text multimodal models in the biomedical field. Finally, we categorize the challenges faced in the development and application of general models into external factors and intrinsic factors, further refining them into 2 external factors and 5 intrinsic factors, and propose targeted solutions, providing guidance for future research directions. For more details and data, please visit our GitHub page: https://github.com/i2vec/A-survey-on-image-text-multimodal-models.

2.
Int J Clin Pharm ; 2024 May 30.
Artigo em Inglês | MEDLINE | ID: mdl-38814514

RESUMO

BACKGROUND: Camrelizumab combined with rivoceranib has been proven effective for treating unresectable hepatocellular carcinoma (uHCC). However, their higher prices than sorafenib could impose a substantial economic burden on patients. AIM: This study aimed to evaluate the relative cost-effectiveness of the combination of camrelizumab and rivoceranib versus sorafenib as first-line therapy for patients with uHCC from the perspective of the US and Chinese payers. METHOD: Using data from the CARES-310 trial, a partitioned survival model (PSM) was developed, considering the perspectives of the US and Chinese payers. The model employed a 15-year time horizon and a biweekly cycle. Direct medical costs and utility data were collected from previous studies and open-access databases. Primary outcomes included quality-adjusted life years (QALYs) and the incremental cost-effectiveness ratio (ICER). Price simulations, sensitivity analyses, and subgroup analyses were conducted. RESULTS: The ICER for the US and China was $122,388.62/QALY and $30,410.56/QALY, respectively, falling below the willingness-to-pay (WTP) thresholds of $150,000/QALY for the US and $35,898.87/QALY for China. Price simulations indicated the cost-effectiveness of camrelizumab plus rivoceranib when the price of camrelizumab (200 mg) remained below $6275.19 in the US and $558.09 in China. The primary determinant of cost-effectiveness in both regions was the cost of camrelizumab. CONCLUSION: The combination of camrelizumab and rivoceranib is a cost-effective first-line therapy for uHCC in both the US and China. Lowering their prices could significantly influence their cost-effectiveness and accessibility to patients. These findings will guide clinicians in treating uHCC and help decision-makers formulate value-based drug pricing strategies.

3.
Nat Commun ; 15(1): 1225, 2024 Feb 09.
Artigo em Inglês | MEDLINE | ID: mdl-38336952

RESUMO

High quantum efficiency and wide-band detection capability are the major thrusts of infrared sensing technology. However, bulk materials with high efficiency have consistently encountered challenges in integration and operational complexity. Meanwhile, two-dimensional (2D) semimetal materials with unique zero-bandgap structures are constrained by the bottleneck of intrinsic quantum efficiency. Here, we report a near-mid infrared ultra-miniaturized graphene photodetector with configurable 2D potential well. The 2D potential well constructed by dielectric structures can spatially (laterally and vertically) produce a strong trapping force on the photogenerated carriers in graphene and inhibit their recombination, thereby improving the external quantum efficiency (EQE) and photogain of the device with wavelength-immunity, which enable a high responsivity of 0.2 A/W-38 A/W across a broad infrared detection band from 1.55 to 11 µm. Thereafter, a room-temperature detectivity approaching 1 × 109 cm Hz1/2 W-1 is obtained under blackbody radiation. Furthermore, a synergistic effect of electric and light field in the 2D potential well enables high-efficiency polarization-sensitive detection at tunable wavelengths. Our strategy opens up alternative possibilities for easy fabrication, high-performance and multifunctional infrared photodetectors.

4.
Rheumatol Ther ; 11(2): 269-283, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38236456

RESUMO

INTRODUCTION: Nonsteroidal anti-inflammatory drugs (NSAIDs) are the primary treatment for osteoarthritis (OA), but prolonged use has adverse effects and varying efficacy. Among NSAIDs, imrecoxib, a selective cyclooxygenase-2 (COX-2) inhibitor, reduces side effects yet remains ineffective for half of the patient population. This study aims to identify biomarkers for early evaluation of imrecoxib efficacy in OA for personalized therapy optimization. METHODS: From September 2021 to January 2022, imrecoxib was administered to patients with OA at Nanjing Drum Tower Hospital. Plasma samples from these patients underwent proteomic analysis through the four-dimensional data-independent acquisition (4D-DIA) method, followed by bioinformatics analysis. Potential differentially expressed proteins (DEPs) were validated using enzyme-linked immunosorbent assays (ELISA). RESULTS: Sixty-six patients with knee OA were included and divided into responders (n = 35) and non-responders (n = 31). Proteomic analysis was conducted on 15 patients from each group, with ELISA validation for every patient. We found 140 DEPs between the two groups after imrecoxib treatment, characterized by 29 proteins showing upregulation and 111 displaying downregulation (P < 0.05, fold change > ± 1.2). Galectin-1 (LGALS1), galectin-3 (LGALS3), and cluster of differentiation 44 (CD44) were identified as potential markers for evaluating clinical response to imrecoxib in OA following ELISA validation. CONCLUSION: This study successfully identified biomarkers for evaluating imrecoxib's clinical response in patients with OA using 4D-DIA technology. These biomarkers may play a vital role in future personalized OA treatment strategies, pending further confirmation.

5.
Appl Microbiol Biotechnol ; 108(1): 68, 2024 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-38194135

RESUMO

Heme is an iron-containing porphyrin compound widely used in the fields of healthcare, food, and medicine. Compared to animal blood extraction, it is more advantageous to develop a microbial cell factory to produce heme. However, heme biosynthesis in microorganisms is tightly regulated, and its accumulation is highly cytotoxic. The current review describes the biosynthetic pathway of free heme, its fermentation production using different engineered bacteria constructed by metabolic engineering, and strategies for further improving heme synthesis. Heme synthetic pathway in Bacillus subtilis was modified utilizing genome-editing technology, resulting in significantly improved heme synthesis and secretion abilities. This technique avoided the use of multiple antibiotics and enhanced the genetic stability of strain. Hence, engineered B. subtilis could be an attractive cell factory for heme production. Further studies should be performed to enhance the expression of heme synthetic module and optimize the expression of heme exporter and fermentation processes, such as iron supply. KEY POINTS: • Strengthening the heme biosynthetic pathway can significantly increase heme production. • Heme exporter overexpression helps to promote heme secretion, thereby further promoting excessive heme synthesis. • Engineered B. subtilis is an attractive alternative for heme production.


Assuntos
Heme , Porfirinas , Animais , Fermentação , Antibacterianos , Ferro
6.
Nat Commun ; 15(1): 141, 2024 Jan 02.
Artigo em Inglês | MEDLINE | ID: mdl-38167874

RESUMO

Photogating effect is the dominant mechanism of most high-responsivity two-dimensional (2D) material photodetectors. However, the ultrahigh responsivities in those devices are intrinsically at the cost of very slow response speed. In this work, we report a WSe2/Ta2NiSe5 heterostructure detector whose photodetection gain and response speed can be enhanced simultaneously, overcoming the trade-off between responsivity and speed. We reveal that photogating-assisted tunneling synergistically allows photocarrier multiplication and carrier acceleration through tunneling under an electrical field. The photogating effect in our device features low-power consumption (in the order of nW) and shows a dependence on the polarization states of incident light, which can be further tuned by source-drain voltages, allowing for wavelength discrimination with just a two-electrode planar structure. Our findings offer more opportunities for the long-sought next-generation photodetectors with high responsivity, fast speed, polarization detection, and multi-color sensing, simultaneously.

7.
Risk Manag Healthc Policy ; 16: 2447-2458, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-38024498

RESUMO

Background: Tislelizumab plus chemotherapy improved overall survival compared to chemotherapy alone, while maintaining an acceptable level of safety. But it's still unclear which strategy is the most cost-effective. The objective of the study was to compare the cost-effectiveness of tislelizumab plus chemotherapy as first-line therapy for patients with advanced or metastatic esophageal squamous cell carcinoma (ESCC) versus chemotherapy alone. Methods: A partitioned survival model with three states was constructed based on the RATIONALE-306 trial. The model's time horizon was ten years, and its cycle was three weeks. Only direct medical costs were considered from the healthcare perspective in China. Calculations were performed on total costs, quality-adjusted life years (QALYs), and incremental cost-effectiveness ratios (ICERs). One-way sensitivity and probabilistic sensitivity analysis (PSA) were performed to determine the uncertainty regarding model parameters. Results: Tislelizumab plus chemotherapy provided 1.35 QALYs for $26,450.77, while chemotherapy alone provided 0.89 QALY for $16,687.15. Compared to chemotherapy alone, tislelizumab had an ICER of $21,062.09/QALY. At the threshold of three times the Chinese GDP per capita ($38,253/QALY), the PSA indicated that tislelizumab had a 96.4% likelihood of being designated cost-effective. At the threshold of 1.5 times the Chinese GDP per capita ($19,126.5/QALY), the PSA indicated that tislelizumab had a probability of 48.7% of being designated cost-effective. Conclusion: Tislelizumab plus chemotherapy as the first treatment for patients with advanced or metastatic ESCC may be a cost-effective option compared to chemotherapy alone at 3 times Chinese GDP per capita.

8.
Nanoscale ; 15(37): 15334-15343, 2023 Sep 29.
Artigo em Inglês | MEDLINE | ID: mdl-37698046

RESUMO

Sodium ion capacitors (SICs) that combine the merits of both rechargeable batteries and supercapacitors have gained widespread recognition for their high energy density and extended cycle life as new energy storage devices. However, the purposeful design of advanced battery-type anodes has become an urgent need to remedy the dynamics mismatch with the capacitive cathode. Herein, we propose a simple but efficient bottom-up approach to build three-dimensional Mo2C/C hybrid architectures in situ as anodes for SICs. By finely regulating the ratio of carbon and molybdenum sources, the optimized Mo2C/C, where even thinner subunit assembled Mo2C nanodisk (∼47.1 nm in thickness) arrays are immobilized on carbon nanosheet substrate via the synchronous embedded growth, rapid electron and ion diffusion/transport expressways, abundant active sites and robust structural stability were achieved for efficient sodium storage. Benefiting from the synergistic contributions of the components, the optimum Mo2C/C anode displays an outstanding rate and long-cycle properties as a competitive anode. Moreover, the constructed Mo2C/C-based SICs exhibited an energy density of ∼16.7 W h kg-1 at 10 kW h kg-1, along with ∼22.5% capacitance degradation over 4000 cycles at 1 A g-1. This contribution will guide the precise synthesis of other versatile Mo2C-based hybrids towards energy-related applications and beyond.

9.
Metab Eng ; 79: 182-191, 2023 09.
Artigo em Inglês | MEDLINE | ID: mdl-37579915

RESUMO

Hypermutation is a robust phenotype characterized by high elevation of spontaneous mutation rates, which has been shown to facilitate rapid adaptation to the stressful environments by hitchhiking with favorable mutations. Accumulating evidence argues that deficient DNA repair can give rise to hypermutation events in bacteria. Here, we provided a comprehensive survey of DNA repair systems to identify promising targets ensuring high DNA fidelity in Corynebacterium glutamicum. Four effective DNA repair factors, including nucS, tag, xpb, and dinP, were found to be strongly associated with the occurrence of hypermutable phenotypes, and these targets were then engineered to establish a CRISPRi-based all-in-one plasmid system for genome mutagenesis. On the basis of these findings, we presented a novel evolutionary engineering method named "DNA repair-assisted genome evolution (DRAGON)". As a proof-of-concept, DRAGON strategy was successfully applied to facilitate rapid acquisition of microbial robustness in C. glutamicum, such as increased tolerances towards kanamycin, acidic pH and high L-serine, showing its promise and potential for rapid strain improvement. Overall, our study will offer new insights into the understanding of DNA repair and evolutionary adaptation in C. glutamicum.


Assuntos
Corynebacterium glutamicum , Corynebacterium glutamicum/genética , Plasmídeos , Mutagênese , Reparo do DNA/genética , Evolução Molecular
11.
Nat Commun ; 13(1): 3859, 2022 07 05.
Artigo em Inglês | MEDLINE | ID: mdl-35790752

RESUMO

Infrared (IR) plasmonic nanoantennas (PNAs) are powerful tools to identify molecules by the IR fingerprint absorption from plasmon-molecules interaction. However, the sensitivity and bandwidth of PNAs are limited by the small overlap between molecules and sensing hotspots and the sharp plasmonic resonance peaks. In addition to intuitive methods like enhancement of electric field of PNAs and enrichment of molecules on PNAs surfaces, we propose a loss engineering method to optimize damping rate by reducing radiative loss using hook nanoantennas (HNAs). Furthermore, with the spectral multiplexing of the HNAs from gradient dimension, the wavelength-multiplexed HNAs (WMHNAs) serve as ultrasensitive vibrational probes in a continuous ultra-broadband region (wavelengths from 6 µm to 9 µm). Leveraging the multi-dimensional features captured by WMHNA, we develop a machine learning method to extract complementary physical and chemical information from molecules. The proof-of-concept demonstration of molecular recognition from mixed alcohols (methanol, ethanol, and isopropanol) shows 100% identification accuracy from the microfluidic integrated WMHNAs. Our work brings another degree of freedom to optimize PNAs towards small-volume, real-time, label-free molecular recognition from various species in low concentrations for chemical and biological diagnostics.


Assuntos
Nanoestruturas , Ácidos Nucleicos Peptídicos , Aprendizado de Máquina , Nanoestruturas/química , Espectrofotometria Infravermelho/métodos , Ressonância de Plasmônio de Superfície/métodos
12.
Front Public Health ; 10: 907222, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35719680

RESUMO

Background: Pain has become an important factor in evaluating patients' quality of life and clinical treatment. For gastric cancer (GC) patients, open radical gastrectomy (OG) causes significant trauma to the body, increases patients' pain after operation, and delays early recovery. The aim of this study was to investigate the predictive factors of acute pain after OG within postoperative 72 h. Methods: From March 2020 to September 2021, 307 patients who underwent OG were included in the study in Nanjing Drum Tower Hospital. The predictors included demographic predictors, pathological data, surgical predictors, and intraoperative predictors. The pain scores at 12, 24, 48, and 72 h after operation were evaluated by numeric rating scale (NRS). The predictors of acute pain were determined by univariate and multivariate analysis. Results: The average pain score (NRS) of patients showed a downward trend over time within 72 h after OG. Multivariate analysis indicated that total gastrectomy (OR 1.823, 95% CI 1.094-3.040, P < 0.05), AJCC TNM stage (II) (OR.232, 95% CI 0.062-0.872, P < 0.05), AJCC TNM stage(III) (OR.185, 95% CI 0.049-0.698, P < 0.05), BMI (kg/m2) (OR 1.75, 95% CI 1.029-2.976, P < 0.05), distant metastasis (OR 3.054, 95% CI 1.019-9.155, P < 0.05), intraoperative transfusion (OR 2.246, 95% CI 1.267-3.982, P < 0.01) were significant predictive factors for acute pain after OG. Conclusion: Reasonable postoperative acute pain control was the prerequisite for accelerating the postoperative rehabilitation of patients. In order to reduce the occurrence of excessive or insufficient analgesia, it was necessary for patients who underwent OG to formulate appropriate analgesics according to risk factors.


Assuntos
Dor Aguda , Laparoscopia , Neoplasias Gástricas , Dor Aguda/etiologia , Dor Aguda/cirurgia , Gastrectomia/efeitos adversos , Humanos , Laparoscopia/efeitos adversos , Dor Pós-Operatória/epidemiologia , Dor Pós-Operatória/etiologia , Dor Pós-Operatória/cirurgia , Qualidade de Vida , Estudos Retrospectivos , Neoplasias Gástricas/etiologia , Neoplasias Gástricas/patologia , Neoplasias Gástricas/cirurgia
13.
ACS Nano ; 16(3): 4458-4466, 2022 Mar 22.
Artigo em Inglês | MEDLINE | ID: mdl-35191301

RESUMO

The photogating effect in hybrid structures has manifested itself as a reliable and promising approach for photodetectors with ultrahigh responsivity. A crucial factor of the photogating effect is the built-in potential at the interface, which controls the separation and harvesting of photogenerated carriers. So far, the primary efforts of designing the built-in potential rely on discovering different materials and developing multilayer structures, which may raise problems in the compatibility with the standard semiconductor production line. Here, we report an enhanced photogating effect in a monolayer graphene photodetector based on a structured substrate, where the built-in potential is established by the mechanism of potential fluctuation engineering. We find that the enhancement factor of device responsivity is related to a newly defined parameter, namely, fluctuation period rate (Pf). Compared to the device without a nanostructured substrate, the responsivity of the device with an optimized Pf is enhanced by 100 times, reaching a responsivity of 240 A/W and a specific detectivity, D*, of 3.4 × 1012 Jones at 1550 nm wavelength and room temperature. Our experimental results are supported by both theoretical analysis and numerical simulation. Since our demonstration of the graphene photodetectors leverages the engineering of structures with monolayer graphene rather than materials with a multilayer complex structure. it should be universal and applicable to other hybrid photodetectors.

14.
iScience ; 25(2): 103799, 2022 Feb 18.
Artigo em Inglês | MEDLINE | ID: mdl-35198867

RESUMO

Terahertz (THz) electromagnetic spectrum ranging from 0.1THz to 10THz has become critical for sixth generation (6G) applications, such as high-speed communication, fingerprint chemical sensing, non-destructive biosensing, and bioimaging. However, the limited response of naturally existing materials THz waves has induced a gap in the electromagnetic spectrum, where a lack of THz functional devices using natural materials has occurred in this gap. Metamaterials, artificially composed structures that can engineer the electromagnetic properties to manipulate the waves, have enabled the development of many THz devices, known as "metadevices". Besides, the tunability of THz metadevices can be achieved by tunable structures using microelectromechanical system (MEMS) technologies, as well as tunable materials including phase change materials (PCMs), electro-optical materials (EOMs), and thermo-optical materials (TOMs). Leveraging various tuning mechanisms together with metamaterials, tremendous research works have demonstrated reconfigurable functional THz devices, playing an important role to fill the THz gap toward the 6G applications. This review introduces reconfigurable metadevices from fundamental principles of metamaterial resonant system to the design mechanisms of functional THz metamaterial devices and their related applications. Moreover, we provide perspectives on the future development of THz photonic devices for state-of-the-art applications.

15.
Sci Adv ; 8(3): eabl9874, 2022 Jan 21.
Artigo em Inglês | MEDLINE | ID: mdl-35044819

RESUMO

Security is a prevailing concern in communication as conventional encryption methods are challenged by progressively powerful supercomputers. Here, we show that biometrics-protected optical communication can be constructed by synergizing triboelectric and nanophotonic technology. The synergy enables the loading of biometric information into the optical domain and the multiplexing of digital and biometric information at zero power consumption. The multiplexing process seals digital signals with a biometric envelope to avoid disrupting the original high-speed digital information and enhance the complexity of transmitted information. The system can perform demultiplexing, recover high-speed digital information, and implement deep learning to identify 15 users with around 95% accuracy, irrespective of biometric information data types (electrical, optical, or demultiplexed optical). Secure communication between users and the cloud is established after user identification for document exchange and smart home control. Through integrating triboelectric and photonics technology, our system provides a low-cost, easy-to-access, and ubiquitous solution for secure communication.

16.
ACS Nano ; 15(6): 10084-10094, 2021 Jun 22.
Artigo em Inglês | MEDLINE | ID: mdl-34060811

RESUMO

Mid-infrared absorption spectroscopy plays an important role in molecule identification and quantification for widespread applications. Integrated photonics provides opportunities to perform spectroscopic sensing on-chip for the minimization of device size, cost, and power consumption. The integration of waveguides and photodetectors is an indispensable step toward the realization of these on-chip sensing systems. It is desired to extend the operating wavelengths of these on-chip sensing systems to the long-wave infrared (LWIR) range to utilize more molecular absorption fingerprints. However, the development of LWIR waveguide-integrated photodetectors faces challenges from both waveguide platforms due to the bottom cladding material absorption and photodetection technologies due to the low LWIR photon energy. Here, we demonstrate LWIR waveguide-integrated photodetectors through heterogeneous integration of graphene photodetectors and Si waveguides on CaF2 substrates. A high-yield transfer printing method is developed for flexibly integrating the waveguide and substrate materials to solve the bottom cladding material absorption issue. The fabricated Si-on-CaF2 waveguides show low losses in the broad LWIR wavelength range of 6.3-7.1 µm. The graphene photodetector achieves a broadband responsivity of ∼8 mA/W in these low-photon-energy LWIR wavelengths under zero-bias operation with the help of waveguide integration and plasmonic enhancement. We further integrate the graphene photodetector with a Si-on-CaF2 folded waveguide and demonstrate on-chip absorption sensing using toluene as an example. These results reveal the potential of our technology for the realization of chip-scale, low-cost, and low-power-consumption LWIR spectroscopic sensing systems.

17.
Nat Commun ; 11(1): 6404, 2020 Dec 17.
Artigo em Inglês | MEDLINE | ID: mdl-33335090

RESUMO

Bulk photovoltaic effect (BPVE), featuring polarization-dependent uniform photoresponse at zero external bias, holds potential for exceeding the Shockley-Queisser limit in the efficiency of existing opto-electronic devices. However, the implementation of BPVE has been limited to the naturally existing materials with broken inversion symmetry, such as ferroelectrics, which suffer low efficiencies. Here, we propose metasurface-mediated graphene photodetectors with cascaded polarization-sensitive photoresponse under uniform illumination, mimicking an artificial BPVE. With the assistance of non-centrosymmetric metallic nanoantennas, the hot photocarriers in graphene gain a momentum upon their excitation and form a shift current which is nonlocal and directional. Thereafter, we demonstrate zero-bias uncooled mid-infrared photodetectors with three orders higher responsivity than conventional BPVE and a noise equivalent power of 0.12 nW Hz-1/2. Besides, we observe a vectorial photoresponse which allows us to detect the polarization angle of incident light with a single device. Our strategy opens up alternative possibilities for scalable, low-cost, multifunctional infrared photodetectors.

18.
Opt Express ; 28(21): 30736-30747, 2020 Oct 12.
Artigo em Inglês | MEDLINE | ID: mdl-33115068

RESUMO

Integrated mid-infrared sensing offers opportunities for the compact, selective, label-free and non-invasive detection of the absorption fingerprints of many chemical compounds, which is of great scientific and technological importance. To achieve high sensitivity, the key is to boost the interaction between light and analytes. So far, approaches like leveraging the slow light effect, increasing optical path length and enhancing the electric field confinement (f) in the analyte are envisaged. Here, we experimentally investigate a slow light one-dimensional photonic crystal ring resonator operating at high-order photonic bandgap (PBG) in mid-infrared range, which features both strong field confinement in analyte and slow light effect. And the optical path length can also be improved by the resoantor compared with waveguide structure. The characteristics of the first- and second-order bandgap edges are studied by changing the number of patterned periodical holes while keeping other parameters unchanged to confine the bands in the measurement range of our setup between 3.64 and 4.0 µm. Temperature sensitivity of different modes is also experimentally studied, which helps to understand the field confinement. Compared to the fundamental PBG edge modes, the second PBG edge modes show a higher field confinement in the analyte and a comparable group index, leading to larger light-matter interaction. Our work could be used for the design of ultra-sensitive integrated mid-infrared sensors, which have widespread applications including environment monitoring, biosensing and chemical analysis.

19.
Appl Opt ; 59(16): 4939-4952, 2020 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-32543491

RESUMO

The Lyot coronagraph is a widely known astronomical instrument used to realize direct imaging of exoplanets, and designing transmittance of an apodizer and Lyot stop is the key to obtaining high-contrast imaging. In this paper a new (to the best of our knowledge) optimization procedure used to design the apodizer and Lyot stop in the Lyot coronagraph is proposed. A two-step optimization program is established to obtain the optimum transmittance of an apodizer and Lyot stop in a sequential way. By using the optimized apodizer and Lyot stop obtained through the proposed optimization procedure, both the stellar light and its diffraction light could be strongly suppressed. Numerical results indicate that such an optimized Lyot coronagraph can produce a 1e-10 extinction of the stellar light near the diffraction limit (1.59λ/D), and a high contrast imaging of 1e-07 could still be obtained even with the influence of light intensity of planets themselves. In addition, the two-step optimization procedure brings in two benefits. First, the two-step optimization is approximately 1000 times faster than the joint optimization method [J. Astron. Telesc. Instrum. Syst.2, 011012 (2016)2329-412410.1117/1.JATIS.2.1.011012]. Second, the optimum transmittance of the Lyot stop is binary, and therefore, the requirements of the production process are reduced, resulting in a greatly reduced cost. At the same time, the performance of the optimized Lyot coronagraph is also analyzed in the case of a monochromatic light incident and bandwidth light incident, and the effect of the diameter of the Lyot stop on the results is also discussed in this paper, which makes sense when designing a coronagraph.

20.
Opt Express ; 28(5): 6251-6260, 2020 Mar 02.
Artigo em Inglês | MEDLINE | ID: mdl-32225878

RESUMO

Vernier effect has been captivated as a promising approach to achieve high-performance photonic sensors. However, experimental demonstration of such sensors in mid-infrared (MIR) range, which covers abundant absorption fingerprints of molecules, is still lacking. Here, we report Vernier effect-based thermally tunable photonic sensors using cascaded ring resonators fabricated on the silicon-on-insulator (SOI) platform. The radii and the coupling gaps in two rings are investigated as key design parameters. By applying organic liquids on our device, we observe an envelope shift of 48 nm with a sensitivity of 3000 nm/RIU and an intensity drop of 6.7 dB. Besides, our device can be thermally tuned with a sensitivity of 0.091 nm/mW. Leveraging the characteristic molecular absorption in the MIR, our work offers new possibilities for complex index sensing, which has wide applications in on-chip photonic sensors.

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