Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 76
Filtrar
1.
J Stroke Cerebrovasc Dis ; 33(10): 107920, 2024 Aug 08.
Artigo em Inglês | MEDLINE | ID: mdl-39122055

RESUMO

INTRODUCTION: Wernekinck commissure syndrome (WCS) is an extremely rare midbrain syndrome, which selectively destroys the decussation of the superior cerebellar peduncle and the central tegmental tract, which commonly presents with bilateral cerebellar ataxia, dysarthria, and internuclear ophthalmoplegia. Palatal myoclonus in Wernekinck commissure syndrome is uncommon and often occurs as a late phenomenon due to hypertrophic degeneration of bilateral inferior olivary nuclei. MATERIAL AND METHOD: A patient with WCS, admitted to our hospital from December 2023, was chosen for this study, and the syndrome's clinical manifestations, imaging features, and etiology were retrospectively analyzed based on the literature. A 68-year-old right-handed East Asian man presented with dizziness, slurred speech, difficulty with swallowing and walking, and rhythmic contractions of the soft palate. He had several risk factors for ischemic cerebrovascular diseases (age, sex, dyslipidemia, hypertension and smoking history). Brain magnetic resonance imaging showed hyperintensity of DWI and hypointensity of ADC at the caudal midbrain which was around the paramedian mesencephalic tegmentum anterior to the aqueduct of midbrain. RESULTS: He was diagnosed with Wernekinck commissure syndrome (WCS) secondary to caudal paramedian midbrain infarction. He was started on dual antiplatelet therapy (aspirin and clopidogrel) and intensive statin therapy. Blood pressure and glucose were also adjusted. His symptoms improved rapidly, and he walked steadily and speak clearly after 7 days of treatment. CONCLUSIONS: Palatal myoclonus is known to occur as a late phenomenon due to hypertrophic degeneration of bilateral inferior olivary nuclei. However, Our case suggests that palatal myoclonus can occur in the early stages in WCS.

2.
Dig Dis Sci ; 2024 Jul 17.
Artigo em Inglês | MEDLINE | ID: mdl-39020183

RESUMO

OBJECTIVE: NK cells play a vital role in tumor immune resistance. Various factors affect NK cell activity. While NK cell dysfunction has been observed in numerous malignancies, the underlying mechanisms in gastric cancer remain unclear. METHOD: Flow cytometry was used to identify the phenotypic distribution and expression of activated receptors on NK cells. ELISA was used to determine the expression of cytokines. We examined the expression of NK cell-related genes and explored their association with survival and prognosis. Additionally, we conducted PCR detection of miR-552-5p expression levels in plasma exosomes of patients and investigated its correlation with phenotypic distribution and activated receptors. We used flow cytometry and ELISA to verify the role of miR-552-5p in NK cell dysfunction. Furthermore, we investigated the potential role of PD-1/PD-L1 in regulating NK cell dysfunction in patients' cells. RESULTS: We observed a significant decrease in the percentage of NKG2D and NKp30 and IFN-γ and TNF-α in patients than in healthy volunteers. Patients with low levels of CD56, CD16, NKG2D, and NKP46 exhibited poorer survival prognoses. Moreover, increased expression levels of plasma exosomal miR-552-5p in patients were negatively associated with NK cell phenotypic distribution and activated receptor expression. MiR-552-5p downregulated the secretion of perforin, granzyme, and IFN-γ as well as the expression of NKp30, NKp46, and NKG2D. Additionally, it suppressed the cytotoxicity of NK cells. The inhibitory effect of miR-552-5p, on NK cell function was reversed when anti-PD-L1 antibodies were used. CONCLUSION: Exosomal miR-552-5p targets the PD-1/PD-L1 axis, leading to impaired NK cell function.

3.
Liver Int ; 2024 Jul 22.
Artigo em Inglês | MEDLINE | ID: mdl-39037193

RESUMO

BACKGROUND AND AIMS: Distinctive gut microbial profiles have been observed between patients with Wilson disease (WD) and healthy individuals. Despite this, the exact relationship and influence of gut microbiota on the advancement of WD-related liver damage remain ambiguous. This research seeks to clarify the gut microbiota characteristics in both human patients and mouse models of WD, as well as their impact on liver injury. METHODS: Gut microbial features in healthy individuals, patients with WD, healthy mice and mice with early- and late-stage WD were analysed using 16S rRNA gene sequencing. Additionally, WD-afflicted mice underwent treatment with either an antibiotic cocktail (with normal saline as a control) or healthy microbiota (using disease microbiota as a control). The study assessed gut microbiota composition, hepatic transcriptome profiles, liver copper concentrations and hepatic pathological injuries. RESULTS: Patients with hepatic WD and mice with WD-related liver injury displayed altered gut microbiota composition, notably with a significant reduction in Lactobacillus abundance. Additionally, the abundances of several gut genera, including Lactobacillus, Veillonella and Eubacterium coprostanoligenes, showed significant correlations with the severity of liver injury in patients with WD. In WD mice, antibiotic treatment or transplantation of healthy microbiota altered the gut microbial structure, increased Lactobacillus abundance and modified the hepatic transcriptional profile. These interventions resulted in reduced hepatic copper concentration and alleviation of WD-related liver injury. CONCLUSIONS: Individuals and mice with pronounced WD-related liver injury exhibited shifts in gut microbial composition. Regulating gut microbiota through healthy microbiota transplantation emerges as a promising therapeutic approach for treating WD-related liver injury.

4.
Nat Commun ; 15(1): 6057, 2024 Jul 18.
Artigo em Inglês | MEDLINE | ID: mdl-39025843

RESUMO

Although molecular vibronic spectra generation is pivotal for chemical analysis, tackling such exponentially complex tasks on classical computers remains inefficient. Quantum simulation, though theoretically promising, faces technological challenges in experimentally extracting vibronic spectra for molecules with multiple modes. Here, we propose a nontrivial algorithm to generate the vibronic spectra using states with zero displacements (squeezed vacuum states) coupled to a linear optical network, offering ease of experimental implementation. We also fabricate an integrated quantum photonic microprocessor chip as a versatile simulation platform containing 16 modes of single-mode squeezed vacuum states and a fully programmable interferometer network. Molecular vibronic spectra of formic acid and thymine under the Condon approximation are simulated using the quantum microprocessor chip with high reconstructed fidelity ( > 92%). Furthermore, vibronic spectra of naphthalene, phenanthrene, and benzene under the non-Condon approximation are also experimentally simulated. Such demonstrations could pave the way for solving complicated quantum chemistry problems involving vibronic spectra and computational tasks beyond the reach of classical computers.

5.
Phys Rev Lett ; 132(20): 200801, 2024 May 17.
Artigo em Inglês | MEDLINE | ID: mdl-38829067

RESUMO

A fully homomorphic encryption system enables computation on encrypted data without the necessity for prior decryption. This facilitates the seamless establishment of a secure quantum channel, bridging the server and client components, and thereby providing the client with secure access to the server's substantial computational capacity for executing quantum operations. However, traditional homomorphic encryption systems lack scalability, programmability, and stability. In this Letter, we experimentally demonstrate a proof-of-concept implementation of a homomorphic encryption scheme on a compact quantum chip, verifying the feasibility of using photonic chips for quantum homomorphic encryption. Our work not only provides a solution for circuit expansion, addressing the longstanding challenge of scalability while significantly reducing the size of quantum network infrastructure, but also lays the groundwork for the development of highly sophisticated quantum fully homomorphic encryption systems.

6.
ACS Appl Mater Interfaces ; 16(23): 30443-30452, 2024 Jun 12.
Artigo em Inglês | MEDLINE | ID: mdl-38815155

RESUMO

Optical fiber force sensing has attracted considerable interest in biological, materials science, micromanipulation, and medical applications owing to its compact and cost-efficient configuration. However, the glass fiber has an intrinsic high Young's modulus, resulting in force sensors being generally less sensitive. While hyperelastic polymer materials can be utilized to enhance the force sensitivity, the thermodynamic properties of the polymer may weaken the sensing accuracy and reliability. Herein, we demonstrate ultracompact three-dimensional (3D)-printed multicore fiber (MCF) tip probes for simultaneous measurement of nanoforce and temperature with high sensitivity. The sensor is highly sensitive to force-induced deformation due to the special geometric features of the polymer microcantilever, and the high-temperature sensitivity can be implemented through the poly(dimethylsiloxane) (PDMS) microcavity on the same fiber facet. Moreover, the sensitivities of the fiber interferometers are remarkably enhanced by introducing the optical analogue of the Vernier effect. Such a device exhibits a force sensitivity of 56.35 nm/µN, which is more than 103 times that of all-silica fiber force sensors. The PDMS microcavity provides a temperature sensitivity of 1.447 nm/°C, measuring the local temperature of the probe and compensating for temperature crosstalk of the force detection. The proposed compact MCF-tip sensor can simultaneously measure nanoforce and temperature with high sensitivity, facilitating multiparameter sensing in a restricted space environment and showing the potential in miniaturized all-fiber multiparameter sensors.

7.
ACS Nano ; 18(8): 6477-6486, 2024 Feb 27.
Artigo em Inglês | MEDLINE | ID: mdl-38350867

RESUMO

Enhancing light-matter interaction is a key requisite in the realm of optical sensors. Bound states in the continuum (BICs), possessing high quality factors (Q factors), have shown great advantages in sensing applications. Recent theories elucidate the ability of BICs with hybrid metal-dielectric architectures to achieve high Q factors and high sensitivities. However, the experimental validation of the sensing performance in such hybrid systems remains equivocal. In this study, we propose two symmetry-protected quasi-BIC modes in a metal-dielectric metasurface. Our results demonstrate that, under the normal incidence of light, the quasi-BIC mode dominated by dielectric can achieve a high Q factor of 412 and a sensing performance with a high bulk sensitivity of 492.7 nm/RIU (refractive index unit) and a figure of merit (FOM) of 266.3 RIU-1, while the quasi-BIC mode dominated by metal exhibits a stronger surface affinity in the biotin-streptavidin bioassay. These findings offer a promising approach for implementing metasurface-based sensors, representing a paradigm for high-sensitivity biosensing platforms.

8.
Lab Chip ; 23(23): 5039-5046, 2023 11 21.
Artigo em Inglês | MEDLINE | ID: mdl-37909299

RESUMO

Flow cytometry is an essential technique in single particle analysis and cell sorting for further downstream diagnosis, exhibiting high-throughput and multiplexing capabilities for many biological and biomedical applications. Although many hydrodynamic focusing-based microfluidic cytometers have been demonstrated with reduced size and cost to adapt to point-of-care settings, the operating conditions are not characterized systematically. This study presents the flow transition process in the hydrodynamic focusing mechanism when the flow rate or the Reynolds number increases. The characteristics of flow fields and mass transport were studied under various operating conditions, including flow rates and microchannel heights. A transition from the squeezed focusing state to the over-squeezed anti-focusing state in the hydrodynamic focusing regime was observed when the Reynolds number increased above 30. Parametric studies illustrated that the focusing width increased with the Reynolds number but decreased with the microchannel height in the over-squeezed state. The microfluidic cytometric analyses using microbeads and E. coli show that the recovery rate was maintained by limiting the Reynolds number to 30. The detailed analysis of the flow transition will provide new insight into microfluidic cytometric analyses with a broad range of applications in food safety, water monitoring and healthcare sectors.


Assuntos
Hidrodinâmica , Técnicas Analíticas Microfluídicas , Escherichia coli , Microfluídica/métodos , Técnicas Analíticas Microfluídicas/métodos , Citometria de Fluxo
9.
Light Sci Appl ; 12(1): 175, 2023 Jul 14.
Artigo em Inglês | MEDLINE | ID: mdl-37443095

RESUMO

Recent years have witnessed significant progress in quantum communication and quantum internet with the emerging quantum photonic chips, whose characteristics of scalability, stability, and low cost, flourish and open up new possibilities in miniaturized footprints. Here, we provide an overview of the advances in quantum photonic chips for quantum communication, beginning with a summary of the prevalent photonic integrated fabrication platforms and key components for integrated quantum communication systems. We then discuss a range of quantum communication applications, such as quantum key distribution and quantum teleportation. Finally, the review culminates with a perspective on challenges towards high-performance chip-based quantum communication, as well as a glimpse into future opportunities for integrated quantum networks.

10.
Brain Behav ; 13(6): e3014, 2023 06.
Artigo em Inglês | MEDLINE | ID: mdl-37062885

RESUMO

BACKGROUND: Morphological changes of retina in patients with Wilson's disease (WD) can be found by optical coherence tomography (OCT), and such changes had significant differences between neurological forms (NWD) and hepatic forms (HWD) of WD. The aim of this study was to evaluate the relationship between morphological parameters of retina and brain magnetic resonance imaging (MRI) lesions, course of disease, type of disease, and sexuality in WD. METHODS: A total of 46 WD patients and 40 health controls (HC) were recruited in this study. A total of 42 WD patients were divided into different groups according to clinical manifestations, course of disease, sexuality, and brain MRI lesions. We employed the Global Assessment Scale to assess neurological severity of WD patients. All WD patients and HC underwent retinal OCT to assess the thickness of inner limiting membrane (ILM) layer to retinal pigment epithelium layer and inner retina layer (ILM to inner plexiform layer, ILM-IPL). RESULTS: Compared to HWD, NWD had thinner superior parafovea zone (108.07 ± 6.89 vs. 114.40 ± 5.54 µm, p < .01), temporal parafovea zone (97.17 ± 6.65 vs. 103.60 ± 4.53 µm, p < .01), inferior parafovea zone (108.114 ± 7.65 vs. 114.93 ± 5.84 µm, p < .01), and nasal parafovea zone (105.53 ± 8.01 vs. 112.10 ± 5.44 µm, p < .01) in inner retina layer. Course of disease influenced the retina thickness. Male patients had thinner inner retina layer compared to female patients. CONCLUSION: Our results demonstrated that WD had thinner inner retina layer compared to HC, and NWD had thinner inner retina layer compared to HWD. We speculated the thickness of inner retina layer may be a potential useful biomarker for NWD.


Assuntos
Degeneração Hepatolenticular , Humanos , Masculino , Feminino , Degeneração Hepatolenticular/diagnóstico por imagem , Degeneração Hepatolenticular/patologia , Tomografia de Coerência Óptica/métodos , Retina/diagnóstico por imagem , Retina/patologia
11.
BMC Neurol ; 23(1): 89, 2023 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-36855079

RESUMO

OBJECTIVE: To analyze and explore the risk factors for neurological symptoms in patients with purely hepatic Wilson's disease (WD) at diagnosis. METHODS: This retrospective study was conducted at the First Affiliated Hospital of the Guangdong Pharmaceutical University on 68 patients with purely hepatic WD aged 20.6 ± 7.2 years. The physical examinations, laboratory tests, color Doppler ultrasound of the liver and spleen, and magnetic resonance imaging (MRI) of the brain were performed. RESULTS: The elevated alanine transaminase (ALT) and aspartate transaminase (AST) levels and 24-h urinary copper level were higher in the purely hepatic WD who developed neurological symptoms (NH-WD) group than those in the purely hepatic WD (H-WD) group. Adherence to low-copper diet, and daily oral doses of penicillamine (PCA) and zinc gluconate (ZG) were lower in the NH-WD group than those in the H-WD group. Logistic regression analysis showed that insufficient doses of PCA and ZG were associated with the development of neurological symptoms in patients with purely hepatic WD at diagnosis. CONCLUSION: The development of neurological symptoms in patients with purely hepatic WD was closely associated with insufficient doses of PCA and ZG, and the inferior efficacy of copper-chelating agents. During the course of anti-copper treatment, the patient's medical status and the efficacy of copper excretion should be closely monitored.


Assuntos
Degeneração Hepatolenticular , Humanos , Encéfalo , Cobre , Degeneração Hepatolenticular/complicações , Degeneração Hepatolenticular/tratamento farmacológico , Penicilamina/uso terapêutico , Estudos Retrospectivos , Fatores de Risco , Zinco/uso terapêutico
12.
ACS Omega ; 8(11): 9854-9860, 2023 Mar 21.
Artigo em Inglês | MEDLINE | ID: mdl-36969403

RESUMO

In Raman analysis, the substrate material serves very often for signal enhancement, especially when metallic surfaces are involved; however, in other cases, the substrate has an opposite effect as it is the source of a parasitic signal preventing the observation of the sample material of interest. This is particularly true with the advent of microfluidic devices involving either silicon or polymer surfaces. On the other hand, in a vast majority of Raman experiments, the analysis is made on a horizontal support holding the sample of interest. In our paper, we report that a simple tilting of the supporting substrate, in this case, silicon, can drastically decrease and eventually inhibit the Raman signal of the substrate material, leading to an easier observation of the target analyte of the sample, in this case, microplastic particles. This effect is very pronounced especially when looking for tiny particles. Explanation of this trend is provided thanks to a supporting experiment and further numerical simulations that suggest that the lensing effect of the particles plays an important role. These findings may be useful for Raman analysis of other microscale particles having curved shapes, including biological cells.

13.
Sci Adv ; 8(49): eade7556, 2022 Dec 09.
Artigo em Inglês | MEDLINE | ID: mdl-36490329

RESUMO

Polarization singularities and topological vortices in photonic crystal slabs centered at bound states in the continuum (BICs) can be attributed to zero amplitude of polarization vectors. We show that such topological features are also observed in optical forces within the vicinity of BIC, around which the force vectors wind in the momentum space. The topological force carries force topological charge and can be used for trapping and repelling nanoparticles. By tailoring asymmetry of the photonic crystal slab, topological force will contain spinning behavior and shifted force zeros, which can lead to three-dimensional asymmetric trapping. Several off-Γ BICs generate multiple force zeros with various force distribution patterns. Our findings introduce the concepts of topology to optical force around BICs and create opportunities to realize optical force vortices and enhanced reversible forces for manipulating nanoparticles and fluid flow.

14.
Medicine (Baltimore) ; 101(50): e31386, 2022 Dec 16.
Artigo em Inglês | MEDLINE | ID: mdl-36550817

RESUMO

To measure the linear structure of the brain in patients with Wilson's disease (WD) and analyze its correlation with neurological symptoms. A total of 174 patients diagnosed with WD were enrolled. According to the type of clinical presentation, the patients with WD were divided into two groups: neurological (NWD) and hepatic (HWD). Sixty healthy volunteers were assigned to a control group. All patients with WD and healthy controls underwent brain magnetic resonance imaging (MRI). The severity of the neurological symptoms was assessed using the Burke Fahn Marsden Movement subscale (BFM-M). Linear brain measurements were performed using T1-weighted MRI scans of all the patients, and the correlation between these linear indices and BFM-M score was investigated. The Huckman index, third ventricle width, and sulcus width of the NWD group were significantly higher than those of the HWD and control groups (P < .05). The frontal horn index, ventricular index, and lateral ventricular body width index of the NWD group were significantly lower than those of the HWD and control groups (P < .05). The Huckman index and third ventricle width of the HWD group were higher than those of the control group (P < .05), whereas the body width index of the lateral ventricle was lower than that of the control group (P < .05). The BFM-M score correlated with the Huckman index (r = 0.29, P < .05), third ventricle width (r = 0.426, P < .001), and lateral ventricular body width index (r = -0.19, P < .05). This study demonstrated significant changes in the linear structure of patients with WD. Linear brain measurement analysis could be used as a potential method to assess the severity of neurological symptoms in WD.


Assuntos
Degeneração Hepatolenticular , Humanos , Degeneração Hepatolenticular/diagnóstico , Encéfalo/patologia , Imageamento por Ressonância Magnética
15.
Front Neurol ; 13: 1018529, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36530638

RESUMO

Background: Mitochondrial encephalomyopathy with lactic acidosis and stroke-like episodes (MELAS) is one of the most common maternally inherited mitochondrial diseases which rarely affects elderly people. Case presentation: We reported the case of a 61-year-old male patient with MELAS. He was experiencing acute migraine-like headaches as the first symptoms. Laboratory data showed elevated lactate and creatine kinase levels. Brain magnetic resonance imaging (MRI) found a high signal intensity lesion in the left occipital-temporal-parietal lobe on diffusion-weighted imaging (DWI). Magnetic resonance angiography (MRA) revealed reversible vasoconstriction of the middle cerebral arteries and superficial temporal arteries. A muscle biopsy suggested minor muscle damage. A genetic study revealed a mitochondrial DNA A3243G mutation. Conclusion: Elderly onset of MELAS is rare and easily misdiagnosed as an ischemic stroke. MELAS with the onset of stroke-like episodes should be considered in adult or elderly patients with imaging findings that are atypical for cerebral infarction. The use of multimodal MRI in the clinical diagnosis of MELAS could be extremely beneficial.

16.
Sci Adv ; 8(48): eabn2291, 2022 Dec 02.
Artigo em Inglês | MEDLINE | ID: mdl-36449614

RESUMO

Transverse spin momentum related to the spin angular momentum (SAM) of light has been theoretically studied recently and predicted to generate an intriguing optical lateral force (OLF). Despite extensive studies, there is no direct experimental evidence of a stable OLF resulting from the dominant SAM rather than the ubiquitous spin-orbit interaction in a single light beam. Here, we theoretically unveil the nontrivial physics of SAM-correlated OLF, showing that the SAM is a dominant factor for the OLF on a nonabsorbing particle, while an additional force from the canonical (orbital) momentum is exhibited on an absorbing particle due to the spin-orbit interaction. Experimental results demonstrate the bidirectional movement of 5-µm-diameter particles on both sides of the beam with opposite spin momenta. The amplitude and sign of this force strongly depend on the polarization. Our optofluidic platform advances the exploitation of exotic forces in systems with a dominant SAM, facilitating the exploration of fascinating light-matter interactions.

17.
Sci Adv ; 8(40): eabn9783, 2022 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-36206336

RESUMO

Quantum autoencoders serve as efficient means for quantum data compression. Here, we propose and demonstrate their use to reduce resource costs for quantum teleportation of subspaces in high-dimensional systems. We use a quantum autoencoder in a compress-teleport-decompress manner and report the first demonstration with qutrits using an integrated photonic platform for future scalability. The key strategy is to compress the dimensionality of input states by erasing redundant information and recover the initial states after chip-to-chip teleportation. Unsupervised machine learning is applied to train the on-chip autoencoder, enabling the compression and teleportation of any state from a high-dimensional subspace. Unknown states are decompressed at a high fidelity (~0.971), obtaining a total teleportation fidelity of ~0.894. Subspace encodings hold great potential as they support enhanced noise robustness and increased coherence. Laying the groundwork for machine learning techniques in quantum systems, our scheme opens previously unidentified paths toward high-dimensional quantum computing and networking.

18.
Biosens Bioelectron ; 215: 114594, 2022 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-35932553

RESUMO

Rapid and sensitive Escherichia coli (E. coli) detection is important in determining environmental contamination, food contamination, as well as bacterial infection. Conventional methods based on bacterial culture suffer from long testing time (24 h), whereas novel nucleic acid-based and immunolabelling approaches are hindered by complicated operation, the need of complex and costly equipment, and the lack of differentiation of live and dead bacteria. Herein, we propose a chemiluminescence digital microwell array chip based on the hydrolysis of 6-Chloro-4-methylumbelliferyl-ß-D-glucuronide by the ß-D-glucuronidase in E. coli to achieve fast single bacterial fluorescence detection. Taking the advantage of the picoliter microwells, single bacteria are digitally encapsulated in these microwells, thus the accurate quantification of E. coli can be realized by counting the number of positive microwells. We also show that the chemiluminescence digital microwell array chip is not affected by the turbidity of the test samples as well as the temperature. Most importantly, our method can differentiate live and dead bacteria through bacterial proliferation and enzyme expression, which is confirmed by detecting E. coli after pH and chlorination treatment. By comparing with the standard method of plate counting, our method has comparable performance but significantly reduces the testing time from over 24 h-2 h and 4 h for qualitative and quantitative analysis, respectively. In addition, the microfluidic chip is portable and easy to operate without external pump, which is promising as a rapid and on-site platform for single E. coli analysis in water and food monitoring, as well as infection diagnosis.


Assuntos
Técnicas Biossensoriais , Infecções por Escherichia coli , Escherichia coli , Humanos , Luminescência , Microfluídica/métodos
19.
Phys Rev Lett ; 129(5): 053902, 2022 Jul 29.
Artigo em Inglês | MEDLINE | ID: mdl-35960581

RESUMO

Elliptically polarized light waves carry the spin angular momentum (SAM), so they can exert optical torques on nanoparticles. Usually, the rotation follows the same direction as the SAM due to momentum conservation. It is counterintuitive to observe the reversal of optical torque acting on an ordinary dielectric nanoparticle illuminated by an elliptically or circularly polarized light wave. Here, we demonstrate that negative optical torques, which are opposite to the direction of SAM, can ubiquitously emerge when elliptically polarized light waves are impinged on dielectric nanoparticles obliquely. Intriguingly, the rotation can be switched between clockwise and counterclockwise directions by controlling the incident angle of light. Our study suggests a new playground to harness polarization-dependent optical force and torque for advancing optical manipulations.

20.
ACS Nano ; 16(8): 11598-11618, 2022 08 23.
Artigo em Inglês | MEDLINE | ID: mdl-35960685

RESUMO

Metasurfaces are 2D artificial materials consisting of arrays of metamolecules, which are exquisitely designed to manipulate light in terms of amplitude, phase, and polarization state with spatial resolutions at the subwavelength scale. Traditional micro/nano-optical sensors (MNOSs) pursue high sensitivity through strongly localized optical fields based on diffractive and refractive optics, microcavities, and interferometers. Although detections of ultra-low concentrations of analytes have already been demonstrated, the label-free sensing and recognition of complex and unknown samples remain challenging, requiring multiple readouts from sensors, e.g., refractive index, absorption/emission spectrum, chirality, etc. Additionally, the reliability of detecting large, inhomogeneous biosamples may be compromised by the limited near-field sensing area from the localization of light. Here, we review recent advances in metasurface-based MNOSs and compare them with counterparts using micro-optics from aspects of physics, working principles, and applications. By virtue of underlying the physics and design flexibilities of metasurfaces, MNOSs have now been endowed with superb performances and advanced functionalities, leading toward highly integrated smart sensing platforms.


Assuntos
Óptica e Fotônica , Refratometria , Reprodutibilidade dos Testes
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA