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Progress in the semiconductor industry relies on the development of increasingly compact devices consisting of complex geometries made from diverse materials. Precise, label-free, and real-time metrology is needed for the characterization and quality control of such structures in both scientific research and industry. However, optical metrology of 2D sub-wavelength structures with nanometer resolution remains a major challenge. Here, a single-shot and label-free optical metrology approach that determines 2D features of nanostructures, is introduced. Accurate experimental measurements with a random statistical error of 18 nm (λ/27) are demonstrated, while simulations suggest that 6 nm (λ/81) may be possible. This is far beyond the diffraction limit that affects conventional metrology. This metrology employs neural network processing of images of the 2D nano-objects interacting with a phase singularity of the incident topologically structured superoscillatory light. A comparison between conventional and topologically structured illuminations shows that the presence of a singularity with a giant phase gradient substantially improves the retrieval of object information in such an optical metrology. This non-invasive nano-metrology opens a range of application opportunities for smart manufacturing processes, quality control, and advanced materials characterization.
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Upconverted UCNPs@mSiO2-NH2 nanoparticles were synthesized via thermal decomposition while employing the energy resonance transfer principle and the excellent near-infrared (NIR) light conversion property of up-conversion. The 808 nm NIR-excited photocontrolled nitric oxide (NO) release platform was successfully developed by electrostatically loading photosensitive NO donor Roussin's black salt (RBS) onto UCNPs@mSiO2-NH2, enabling the temporal, spatial, and dosimetric regulation of NO release for biological applications of NO. The release of NO ranged from 0.015â0.099 mM under the conditions of 2.0 W NIR excitation power, 20 min of irradiation time, and UCNPs@mSiO2-NH2&RBS concentration of 0.25â1.25 mg/mL. Therefore, this NO release platform has an anti-tumor effect. In vitro experiments showed that under the NIR light, at concentrations of 0.3 mg/mL and 0.8 mg/mL of UCNPs@mSiO2-NH2&RBS, the activity of glioma (U87) and chordoma (U-CH1) cells, as measured by CCK8 assay, was reduced to 50 %. Cell flow cytometry and Western Blot experiments showed that NO released from UCNPs@mSiO2-NH2&RBS under NIR light induced apoptosis in brain tumor cells. In vivo experiments employing glioma and chordoma xenograft mouse models revealed significant inhibition of tumor growth in the NIR and UCNPs@mSiO2-NH2&RBS group, with no observed significant side effects in the mice. Therefore, NO released by UCNPs@mSiO2-NH2&RBS under NIR irradiation can be used as a highly effective and safe strategy for brain tumor therapy.
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AIM: To estimate the causal associations of type 2 diabetes and glycaemic traits with cognitive function, and to determine the potential mediating role of various brain imaging-derived phenotypes (IDPs) using Mendelian randomization (MR) analysis. METHODS: Using publicly available summary data, we performed a series of univariable and multivariable MR analysis to infer causality. Two-step MR analysis was then conducted in turn to evaluate the potential mediating role of each brain IDP. RESULTS: There was no evidence of causal associations between type 2 diabetes and cognitive function outcomes. Each 1-SD unit higher genetically predicted fasting proinsulin was associated with worse cognitive performance, as evidenced by both univariable (beta: -0.022; 95% confidence interval [CI] -0.038, -0.007) and multivariable MR analysis (beta: -0.027; 95% CI -0.048, -0.005). In addition, the univariable MR analysis identified several causal associations between fasting proinsulin and brain IDPs, and between brain IDPs and cognitive performance. The inverse association of genetically predicted fasting proinsulin with cognitive performance did not attenuate after adjusting for each of the brain IDPs in multivariable MR analysis. CONCLUSIONS: The present MR study provided credible evidence for the causal association between genetically predicted fasting proinsulin and cognitive function, informing a potential diagnosis and intervention target for patients with cognitive impairment. No significant brain IDP included in this study was identified as lying on the causal pathway from fasting proinsulin to cognitive performance. Future research involving more specific and granular brain IDP or other brain process is warranted to explore the potential biological mechanism underlying the association.
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Glicemia , Encéfalo , Cognição , Diabetes Mellitus Tipo 2 , Análise da Randomização Mendeliana , Proinsulina , Humanos , Diabetes Mellitus Tipo 2/genética , Encéfalo/diagnóstico por imagem , Encéfalo/patologia , Encéfalo/metabolismo , Cognição/fisiologia , Glicemia/metabolismo , Glicemia/análise , Proinsulina/sangue , Proinsulina/metabolismo , Fenótipo , Jejum/sangue , Disfunção Cognitiva/etiologia , Disfunção Cognitiva/genética , Disfunção Cognitiva/epidemiologia , Polimorfismo de Nucleotídeo Único , MasculinoRESUMO
Objective: To evaluate the prevalence and associated factors of undernutrition among children with congenital heart disease (CHD) who have not undergone surgeries in China. Methods: This cross-sectional study included 734 CHD children along with their parents. The outcome of interest was undernutrition, including underweight, wasting, and stunting, defined as Z-scores (i.e., weight-for-age, weight-for-height, and height-for-age) ≤-2, according to the World Health Organization (WHO) growth standard. Exposures of interest, containing demographics, obstetric factors, maternal dietary factors, parents' life behaviors and habits, birth-related factors, cardiac-related factors, and preoperative factors, were analyzed using a multivariate logistic regression model to test their associations with undernutrition in CHD children. Results: Overall, 36.1%, 29.7%, and 21.3% of cases were underweight, wasted, and stunted, respectively. Multivariate logistic regression indicated that underweight was associated with demographic factors (including parents' occupational status, family income, and maternal body mass index pre-pregnancy), low birth weight (OR = 4.60, 2.76-7.70), pulmonary hypertension (OR = 4.46, 3.09-6.43), and pneumonia (OR = 1.88, 1.28-2.76). Artificially-fed children were 2.34 (1.36-4.01) times more likely to be underweight. Occupied mothers (OR = 0.62, 0.44-0.88) and fathers (OR = 0.49, 0.26-0.92) served as protective factors, while mothers having gestational complications (OR = 1.56, 1.11-2.18) and exposed to noisy environment (OR = 1.64, 1.11-2.42) during this pregnancy, and pulmonary hypertension (OR = 3.21, 2.30-4.49) increased the chance of wasting in offspring. The odds of being stunted were greater in families with >2 children (OR = 1.88, 1.13-3.14), placental abruption during this pregnancy (OR = 25.15, 2.55-247.89), preterm births (OR = 1.84, 1.02-3.31), low birth weight (OR = 3.78, 2.16-6.62), pulmonary hypertension (OR = 2.35, 1.56-3.53) and pneumonia (OR = 1.93, 1.28-2.90). In subgroup analyses, the associations differed between patients with different feeding patterns (breastfeeding vs. non-breastfeeding), CHD classifications (cyanotic vs. acyanotic), and prematurity (preterm vs. non-preterm). Conclusion: Undernutrition is common in preoperative CHD children. Familial demographics, maternal factors (including having gestational complications and exposure to noisy environment during pregnancy), and patient-related factors (encompassing preterm births, low birth weight, pulmonary hypertension, pneumonia, and feeding pattern) were found to contribute to undernutrition in CHD cases. However, associated factors among the three subgroups of distinct feeding patterns, CHD categorization, and prematurity exhibited varied outcomes, suggesting the necessity for targeted interventions.
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BACKGROUND: Although current treatments are effective in dealing with congenital heart disease (CHD), non-cardiac comorbidities such as attention-deficit hyperactivity disorder (ADHD) have received widespread attention. The purpose of this systematic review and meta-analysis is to assess the risk of ADHD associated with CHD. METHODS: The literature search was carried out systematically through eight different databases by the end of September 2022. Either a fixed- or a random-effects model was used to calculate the overall combined risk estimates. The heterogeneity of the studies was assessed by the Cochran Q test and the I2 statistic. Subgroup and sensitivity analyses were used to explore the potential sources of heterogeneity. RESULTS: Eleven studies were included in this study, which involved a total of 296 741 participants. Our study showed that the children with CHD were at a significantly increased risk of ADHD compared with the reference group (OR = 2.98, 95% CI: 2.18-4.08). The results were moderately heterogeneous. These factors including study design, geographic region and study quality were identified as the first three of the most relevant heterogeneity moderators by subgroup analyses. Sensitivity analysis yielded consistent results. There was no evidence of publication bias. CONCLUSIONS: The present study suggests that CHD children have a significantly higher risk of ADHD when compared with those without CHD. Early identification and intervention of ADHD is important to reduce its symptoms and adverse effects; therefore, clinicians should increase screening for ADHD in children with CHD and intervene promptly to reduce its effects whenever possible.
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Transtorno do Deficit de Atenção com Hiperatividade , Cardiopatias Congênitas , Criança , Humanos , Transtorno do Deficit de Atenção com Hiperatividade/epidemiologia , Projetos de Pesquisa , Comorbidade , Medição de RiscoRESUMO
In this paper, we present a novel, to the best of our knowledge, photonic scheme for the generation of dual-mode multi-format chirp microwave signals, utilizing a dual-drive dual-parallel Mach-Zehnder modulator (DD-DPMZM). By inputting a single-chirp signal and controlling the input binary sequences, the proposed method can generate up-, down-, dual-, or triangular-chirp signals in both pulse and continuous-wave modes. Moreover, the duty cycle of the generated chirp signals in the pulse mode can be easily adjusted by manipulating the injected binary sequences. The compact structure of the proposed scheme eliminates the need for polarization control in signal switching and avoids the use of any optical filter. Experimental verification confirms the feasibility of our approach, while also pointing towards its promising applications in multi-functional radar systems.
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Species in Triplophysa display strong adaptability to the extreme environment of the plateau, thus offering an ideal model to study the molecular mechanism of fish adaptation to environmental stress. In the present study, we conducted integrated analysis of the transcriptome and metabolism of liver tissue in Triplophysa siluroides under heat stress (28 °C) and control (10 °C) conditions to identify heat stress-induced genes, metabolites and pathways. RNA-Seq identified 2373 differentially expressed genes, which consisted of 1360 upregulated genes and 1013 downregulated genes, in the heat stress group vs. the control group. Genes in the heat shock protein (Hsp) family, including Hsp40, Hsp70, Hsp90 and other Hsps, were strongly upregulated by heat stress. Pathway enrichment analysis revealed that the PI3K/AKT/mTOR and protein processing in the endoplasmic reticulum (ER) pathways were significantly affected by heat stress. Metabolism sequencing identified a total of 155 differentially abundant metabolites, including 118 significantly upregulated metabolites and 37 downregulated metabolites. Combined analysis of the transcriptome and metabolism results showed that ubiquitin-dependent proteolysis and purine metabolism pathways were enhanced in response to acute heat stress to protect cells from damage under stress conditions. The results of this study may contribute to our understanding of the underlying molecular mechanism of the heat stress response in cold-water fish.
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Cipriniformes , Transcriptoma , Animais , Altitude , Fosfatidilinositol 3-Quinases/genética , Perfilação da Expressão Gênica/veterinária , Resposta ao Choque Térmico/genética , Cipriniformes/genéticaRESUMO
Flavonoids have been shown to be beneficial in a variety of inflammatory and metabolic diseases because of their anti-inflammatory and antioxidant properties. However, previous epidemiological studies have only demonstrated a negative correlation between flavonoid intake on inflammatory markers, and the optimal intake of dietary flavonoids and subclasses in terms of dietary anti-inflammatory efficacy remains undetermined. This study was based on 3 cycles (2007-2010, 2017-2018) of the National Health and Nutrition Examination Survey and the corresponding expanded flavonoid database. Weighted multiple linear regression was used to assess linear relationships between flavonoid intake and Dietary inflammation index (DII). Smoothed curve fit and a generalized additive model were used to investigate the nonlinear relationships and threshold effects, the 2-tailed linear regression model was used to find potential inflection points. A total of 12,724 adults were included in the study. After adjusting for potential confounders, flavonoid intake was significantly associated with DII, with the strongest negative association effect for flavonols (-0.40 [-0.45, -0.35]). In subgroup analyses stratified by sex, race, age, body mass index, education levels, and diabetes, flavonol intake maintained a significant negative linear correlation with DII. In addition, we found significant nonlinear relationships (L-shaped relationships) and threshold effects between total flavonoids, flavan-3-ols, and flavanols and DII, with inflection points of 437.65 mg/days, 157.79 mg/days, and 46.36 mg/days, respectively. Our results suggest a threshold for the dietary anti-inflammatory capacity of flavonoid intake in U.S. adults.
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Flavonoides , Polifenóis , Adulto , Humanos , Inquéritos Nutricionais , Antioxidantes , Índice de Massa Corporal , InflamaçãoRESUMO
Existing evidence supported that congenital heart defect (CHD) was associated with a combination of environmental and genetic factors. Based on this, this study aimed at assessing the association of maternal folic acid supplementation (FAS), genetic variations in offspring methylenetetrahydrofolate dehydrogenase (MTHFD)1 and MTHFD2 genes, and their interactions with CHD and its subtypes. A hospital-based case-control study, including 620 cases with CHD and 620 healthy children, was conducted. This study showed that the absence of FAS was significantly associated with an increased risk of total CHD and its subtypes, such as atrial septal defect (ASD). FAS during the first and second trimesters was associated with a significantly higher risk of CHD in offspring compared to FAS during the three months prior to conception. The polymorphisms of offspring MTHFD1 and MTHFD2 genes at rs2236222, rs11849530, and rs828858 were significantly associated with the risk of CHD. Additionally, a significantly positive interaction between maternal FAS and genetic variation at rs828858 was observed for the risk of CHD. These findings suggested that pregnant women should carefully consider the timing of FAS, and individuals with higher genetic risk may benefit from targeted folic acid supplementation as a preventive measure against CHD.
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Cardiopatias Congênitas , Metilenotetra-Hidrofolato Desidrogenase (NADP) , Gravidez , Criança , Feminino , Humanos , Metilenotetra-Hidrofolato Desidrogenase (NADP)/genética , Estudos de Casos e Controles , Cardiopatias Congênitas/genética , Família , Ácido Fólico , Antígenos de Histocompatibilidade Menor/genéticaRESUMO
Non-contact optical temperature sensors are highly sought after by researchers due to their satisfactory temperature resolution (δ(T) < 0.1 °C), high relative thermal sensitivity (Sr > 1% °C-1), fast temporal response (t < 0.1 s), and long-term optical stability. In this study, NaYF4:Yb3+/Ho3+/Tm3+ upconversion nanoparticles were prepared by a solvothermal method, and their crystal structure, microscopic morphology, and luminescence mechanism, together with the temperature sensing properties of the specimens, were investigated. Under 980 nm laser excitation, the specimens exhibited strong upconversion luminescence, and the emission peaks corresponded to the characteristic energy level jumps of Ho3+ and Tm3+, respectively. The temperature-dependent luminescence spectra of the samples were investigated based on the fluorescence intensity ratio (FIR) technique over a temperature gradient of 295-495 K. The samples are based on thermally coupled energy levels (TCLs: 1G4(1,2) â 3H6(Tm3+)) and non-thermally coupled energy levels (NTCLs: 3F3 â 3H6(Tm3+) and 5F3 â 5I8(Ho3+), 3F3 â 3H6(Tm3+) and 1G4 â 3H6(Tm3+), 3F3 â 3H6(Tm3+) and 5F5 â 5I8(Ho3+), 3F3 â 3H6(Tm3+) and 5F4 â 5I8(Ho3+)) for temperature sensing performance. The maximum absolute sensitivity (Sa), relative sensitivity (Sr), and minimum temperature resolution δ(T) were found to be 0.0126 K-1 (495 K), 1.7966% K-1 (345 K), and 0.0167 K, respectively, which are better than those of most sensing materials, and the simultaneous action of multiple coupling energy levels can further improve the temperature precision. This study indicates that the sample has a good value for optical temperature measurement and also provides new ideas for the exploration of other high-quality optical temperature sensing materials.
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CX3C chemokine ligand 1 (CX3CL1) belongs to the CX3C chemokine family and is involved in various disease processes. However, its role in intervertebral disc degeneration (IDD) remains to be elucidated. In the present study, western blotting, reverse transcription-quantitative PCR and ELISA assays were used to assess target gene expression. In addition, immunofluorescence and TUNEL staining were used to assess macrophage infiltration, monocyte migration and apoptosis. The present study aimed to reveal if and how CX3CL1 regulates IDD progression by exploring its effect on macrophage polarization and apoptosis of human nucleus pulposus cells (HNPCs). The data showed that CX3CL1 bound to CX3C motif chemokine receptor 1 (CX3CR1) promoted the M2 phenotype polarization via JAK2/STAT3 signaling, followed by increasing the secretion of anti-inflammatory cytokines from HNPCs. In addition, HNPC-derived CX3CL1 promoted M2 macrophage-derived C-C motif chemokine ligand 17 release thereby reducing the apoptosis of HNPCs. In clinic, the reduction of mRNA and protein levels CX3CL1 in degenerative nucleus pulposus tissues (NPs) was measured. Increased M1 macrophages and pro-inflammatory cytokines were found in NPs of IDD patients with low CX3CL1 expression. Collectively, these findings suggested that the CX3CL1/CX3CR1 axis alleviates IDD by reducing inflammation and apoptosis of HNPCs via macrophages. Therefore, targeting CX3CL1/CX3CR1 axis is expected to produce a new therapeutic approach for IDD.
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A photonic approach for generating dual-band dual-chirp waveforms with the capability of anti-dispersion transmission is proposed. In this approach, an integrated dual-drive dual-parallel Mach-Zehnder modulator (DD-DPMZM) is adopted to realize single-sideband modulation of a RF input and double-sideband modulation of baseband signal-chirped RF signals. By properly presetting the central frequencies of the RF input and the bias voltages of DD-DPMZM, dual-band dual-chirp waveforms with anti-dispersion transmission can be achieved after photoelectronic conversion. A complete theoretical analysis of the operation principle is presented. Full experimental verification of the generation and anti-dispersion transmission of dual-chirp waveforms centered at 2.5 and 7.5 GHz as well as 2 and 6 GHz over two dispersion compensating modules with dispersion values equivalent to 120 km or 100 km standard single-mode fiber is successfully carried out. The proposed system features a simple architecture, excellent reconfigurability, and immunity to dispersion-induced power fading, which are highly desired in distributed multi-band radar networks with optical-fiber-based transmission.
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Metastable optically controlled devices (optical flip-flops) are needed in data storage, signal processing, and displays. Although nonvolatile memory relying on phase transitions in chalcogenide glasses has been widely used for optical data storage, beyond that, weak optical nonlinearities have hindered the development of low-power bistable devices. This work reports a new type of volatile optical bistability in a hybrid nano-optomechanical device, comprising a pair of anchored nanowires decorated with plasmonic metamolecules. The nonlinearity and bistability reside in the mechanical properties of the acoustically driven nanowires and are transduced to the optical response by reconfiguring the plasmonic metamolecules. The device can be switched between bistable optical states with microwatts of optical power and its volatile memory can be erased by removing the acoustic signal. The demonstration of hybrid nano-optomechanical bistability opens new opportunities to develop low-power optical bistable devices.
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Acústica , Dispositivos Ópticos , Processamento de Sinais Assistido por ComputadorRESUMO
Stimulated Brillouin scattering (SBS), originating from the coupling between optical and acoustic waves, has been widely applied in many fields. Silicon is the most used and important material in micro-electromechanical systems (MEMS) and integrated photonic circuits. However, strong acoustic-optic interaction in silicon requires mechanical release of the silicon core waveguide to avoid acoustic energy leakage into the substrate. This will not only reduce the mechanical stability and thermal conduction, but also increase the difficulties for fabrication and large-area device integration. In this paper, we propose a silicon-aluminium nitride(AlN)-sapphire platform for realizing large SBS gain without suspending the waveguide. AlN is used as a buffer layer to reduce the phonon leakage. This platform can be fabricated via the wafer bonding between silicon and commercial AlN-sapphire wafer. We adopt a full-vectorial model to simulate the SBS gain. Both the material loss and the anchor loss of the silicon are considered. We also apply the genetic algorithm to optimize the waveguide structure. By limiting the maximum etching step number to two, we obtain a simple structure to achieve the SBS gain of 2462 W-1m-1 for forward SBS, which is 8 times larger than the recently reported result in unsuspended silicon waveguide. Our platform can enable Brillouin-related phenomena in centimetre-scale waveguides. Our findings could pave the way toward large-area unreleased opto-mechanics on silicon.
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Despite recent tremendous progress in optical imaging and metrology1-6, there remains a substantial resolution gap between atomic-scale transmission electron microscopy and optical techniques. Is optical imaging and metrology of nanostructures exhibiting Brownian motion possible with such resolution, beyond thermal fluctuations? Here we report on an experiment in which the average position of a nanowire with a thermal oscillation amplitude of â¼150 pm is resolved in single-shot measurements with subatomic precision of 92 pm, using light at a wavelength of λ = 488 nm, providing an example of such sub-Brownian metrology with â¼λ/5,300 precision. To localize the nanowire, we employ a deep-learning analysis of the scattering of topologically structured light, which is highly sensitive to the nanowire's position. This non-invasive metrology with absolute errors down to a fraction of the typical size of an atom, opens a range of opportunities to study picometre-scale phenomena with light.
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Nanoestruturas , Nanofios , ElétronsRESUMO
The research of metamaterial shows great potential in the field of solar energy harvesting. In the past decade, the design of broadband solar metamaterial absorber (SMA) has attracted a surge of interest. The conventional design typically requires brute-force optimizations with a huge sampling space of structure parameters. Very recently, deep learning (DL) has provided a promising way in metamaterial design, but its application on SMA development is barely reported due to the complicated features of broadband spectrum. Here, this work develops the DL model based on metamaterial spectrum transformer (MST) for the powerful design of high-performance SMAs. The MST divides the optical spectrum of metamaterial into N patches, which overcomes the severe problem of overfitting in traditional DL and boosts the learning capability significantly. A flexible design tool based on free customer definition is developed to facilitate the real-time on-demand design of metamaterials with various optical functions. The scheme is applied to the design and fabrication of SMAs with graded-refractive-index nanostructures. They demonstrate the high average absorptance of 94% in a broad solar spectrum and exhibit exceptional advantages over many state-of-the-art counterparts. The outdoor testing implies the high-efficiency energy collection of about 1061 kW h m-2 from solar radiation annually. This work paves a way for the rapid smart design of SMA, and will also provide a real-time developing tool for many other metamaterials and metadevices.
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Bacterial motion in porous media is essential for their survival, proper functioning, and various applications. Here we investigated the motion of Escherichia coli bacteria in microsphere-mimicked porous media. We observed reduced bacterial velocity and enhanced directional changes of bacteria as the density of microspheres increased, while such changes happened mostly around the microspheres and due to the collisions with the microspheres. More importantly, we established and quantified the correlation between the bacterial trapping in porous media and the geometric confinement imposed by the microspheres. In addition, numerical simulations showed that the active Brownian motion model in the presence of microspheres resulted in bacterial motion that are consistent with the experimental observations. Our study suggested that it is important to distinguish the ability of bacteria to move easily - bacterial mobility - from the ability of bacteria to move independently - bacteria motility. Our results showed that bacterial motility remains similar in porous media, but bacterial mobility was significantly affected by the pore-scale confinement.
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Bactérias , Movimento , Microesferas , Porosidade , Escherichia coliRESUMO
Computational inverse-design and forward prediction approaches provide promising pathways for on-demand nanophotonics. Here, we use a deep-learning method to optimize the design of split-ring metamaterials and metamaterial-microcavities. Once the deep neural network is trained, it can predict the optical response of the split-ring metamaterial in a second which is much faster than conventional simulation methods. The pretrained neural network can also be used for the inverse design of split-ring metamaterials and metamaterial-microcavities. We use this method for the design of the metamaterial-microcavity with the absorptance peak at 1310 nm. Experimental results verified that the deep-learning method is a fast, robust, and accurate method for designing metamaterials with complex nanostructures.
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Stimulated Brillouin scattering (SBS) has been widely applied in narrow line-width laser, microwave filters, optical gyroscopes, and other fields. However, most research is limited within near-infrared to mid-infrared range. This is due to the limited transparent window in most materials, such as silicon and germanium. Aluminium nitride (AlN) is a novel III-V material with a wide transparent window from 200 nm and an appropriate refractive index to confine the light. In this paper, we first validate the full-vectorial formalism to calculate SBS gain based on the measured results from a silicon platform. Compared to previous research, our model achieves higher accuracy in terms of frequency, Q factor, as well as Brillouin gain coefficient without modifying the waveguide width. It also reveals the importance of matching rotation matrix and crystalline coordinate system. Then, we investigate the SBS in a partially suspended AlN waveguide at 450 nm based on the validated method. It shows a wide tunability in frequency from 16 GHz to 32 GHz for forward SBS and a range from 42 GHz to 49 GHz for backward SBS. We numerically obtain the value of Brillouin gain of 1311 W-1m-1 when Q factor is dominated by anchor loss for forward SBS of transverse electric mode. We also find out that in the case for forward SBS of transverse-magnetic mode, anchor loss could be greatly suppressed when the node point of the selected acoustic mode matches with the position of pillar anchor. Our findings, to the best of our knowledge, pave a new way to obtain Brillouin-related applications in integrated photonic circuit within the visible range.
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We propose and experimentally demonstrate a polarization multiplexed active mode-locking optoelectronic oscillator (AML-OEO) based on a single dual-polarization binary phase-shift keying (DP-BPSK) modulator for frequency tunable dual-band microwave pulse signal generation. In order to realize mode-locking, two single-tone signals whose frequency are integer multiple of the free spectrum range (FSR) of AML-OEO are applied as active modulation signals (AMSs) at the bias ports of the DP-BPSK modulator. By dividing the AML-OEO into two loops with polarization demultiplexing, both the carrier frequency and pulse repetition frequency (PRF) of the dual-band microwave pulses are independently adjustable. In the experiment, microwave pulses with different PRFs of 162.4 kHz, 324.8 kHz and 812 kHz are generated based on fundamental, second-order harmonic and fifth-order harmonic mode-locking, respectively. In addition, the carrier frequency tunability within 4â¼10â GHz is verified by inserting a frequency tunable electrical filter. The phase noise of the generated pulse signal at 10 kHz offset is better than -125 dBc/Hz.