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1.
Sensors (Basel) ; 21(21)2021 Oct 29.
Artigo em Inglês | MEDLINE | ID: mdl-34770491

RESUMO

Among the different types of photonic sensor devices, optical whispering gallery mode resonators (WGMRs) have attracted interest due to their high level of sensitivity, small size, and ability to perform real-time temperature measurements. Here we demonstrate the applicability of temperature measurements using WGMR in both air and liquid environments. We also show that WGMR allowed measurements of the refractive index variations in an evaporating glucose-water solution droplet. The thermal tuning of WGMR can be reduced by coating WGMRs with a thin layer of polymethyl methacrylate (PMMA). Dip-coating the silica microsphere multiple times significantly reduced the resonance shift, partially compensating for the positive thermo-optical coefficient of silica. The shift direction changed the sign eventually.


Assuntos
Glucose , Refratometria , Microesferas , Óptica e Fotônica , Temperatura
2.
Yonsei Med J ; 62(12): 1117-1124, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34816642

RESUMO

PURPOSE: To evaluate the accuracy of the Kane formula for intraocular lens (IOL) power calculation in comparison with existing formulas by incorporating optional variables into calculation. MATERIALS AND METHODS: This retrospective review consisted of 78 eyes of patients who had undergone uneventful phacoemulsification with intraocular implantation at Severance Hospital in Seoul, Korea between February 2020 and January 2021. The Kane formula was compared with six of the existing IOL formulas (SRK/T, Hoffer-Q, Haigis, Holladay1, Holladay2, Barrett Universal II) based on the mean absolute error (MAE), median absolute error (MedAE), and the percentages of eyes within prediction errors of ±0.25D, ±0.50D, and ±1.00D. RESULTS: The Barrett Universal II formula demonstrated the lowest MAEs (0.26±0.17D), MedAEs (0.28D), and percentage of eyes within prediction errors of ±0.25D, ± 0.50D, and ±1.00D, although there was no statistically significant difference between Barrett Universal II-SRK/T (p=0.06), and Barrett Universal II-Kane formula (p<0.51). Following the Barrett Universal II formula, the Kane formula demonstrated the second most accurate formula with MAEs (0.30±0.19D) and MedAEs (0.28D). However, no statistical difference was shown between Kane-Barrett Universal II (p=0.51) and Kane-SRK/T (p=0.14). CONCLUSION: Although slightly better refractory outcome was noted in the Barrett Universal II formula, the performance of the Kane formula in refractive prediction was comparable in IOL power calculation, marking its superiority over many conventional IOL formulas, such as HofferQ, Haigis, Holladay1, and Holladay2.


Assuntos
Lentes Intraoculares , Facoemulsificação , Biometria , Humanos , Implante de Lente Intraocular , Óptica e Fotônica , Refração Ocular , Estudos Retrospectivos
4.
J Refract Surg ; 37(11): 754-758, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34756144

RESUMO

PURPOSE: To compare the accuracy of the Barrett Universal II, Emmetropia Verifying Optical (EVO), Haigis, Kane, and SRK/T formulas for intraocular lens power calculation in patients with high axial myopia. METHODS: In this retrospective study, 175 eyes (175 patients) that underwent uneventful cataract surgery were enrolled. According to the axial length (AL), the eyes were divided into long AL (26 ⩽ AL < 28 mm), super long AL (28 ⩽ AL < 30 mm), and extremely long AL (⩾ 30 mm). The mean absolute prediction errors (MAE) 3 months postoperatively and the percentage of eyes within different prediction error were compared, followed by subgroup analysis. RESULTS: The MAE and percentage of eyes within ±0.50 diopters (D) of the five formulas were as follows: Barrett Universal II (0.342, 74.9%), EVO 2.0 (0.314, 82.3%), Haigis (0.336, 74.9%), Kane (0.318, 78.9%), and SRK/T (0.398, 69.7%) (P = .552 and .071, respectively). Although no significant difference was found among the five formulas in the super and extremely long AL groups (P = .792 and .227, respectively), the EVO 2.0 formula achieved the highest accuracy (88.9%, 72 of 81) in the long AL group (P = .049). Moreover, the accuracy of the EVO 2.0 and Haigis formulas was stable, regardless of AL. The SRK/T formula showed a negative trend in the long and super long AL groups, whereas the Barrett Universal II, Kane, and SRK/T formulas showed positive trends in the extremely long AL group. CONCLUSIONS: Overall, the EVO 2.0 and Kane formulas achieved better results in patients with high axial myopia, whereas the other three formulas showed slightly poor outcomes. [J Refract Surg. 2021;37(11):754-758.].


Assuntos
Lentes Intraoculares , Miopia , Facoemulsificação , Biometria , Humanos , Implante de Lente Intraocular , Miopia/cirurgia , Óptica e Fotônica , Refração Ocular , Estudos Retrospectivos
5.
Sensors (Basel) ; 21(19)2021 Sep 28.
Artigo em Inglês | MEDLINE | ID: mdl-34640783

RESUMO

We report the design of a high-efficiency spectral-domain spectrometer with cylindrical optics for line scanning optical coherence tomography (OCT). The spectral nonlinearity in k space (wavenumber) lowers the depth-dependent signal sensitivity of the spectrometers. For linearizing, in this design, grating and prism have been introduced. For line scanning, a cylindrical mirror is utilized in the scanning part. Line scanning improves the speed of imaging compared to fly-spot scanning. Line scanning OCT requires a spectrometer that utilizes cylindrical optics. In this work, an optical design of a linear wavenumber spectrometer with cylindrical optics is introduced. While there are many works using grating and prism to linearize the K space spectrometer design, there is no work on linearizing the k-space spectrometer with cylindrical optics for line scanning that provides high sensitivity and high-speed imaging without the need for resampling. The design of the spectrometer was achieved through MATLAB and ZEMAX simulations. The spectrometer design is optimized for the broadband light source with a center wavelength of 830 ± 100 nm (8.607 µm-1- 6.756 µm-1 in k-space). The variation in the output angle with respect to the wavenumber can be mentioned as a nonlinearity error. From our design results, it is observed that the nonlinearity error reduced from 147.0115 to 0.0149 Δθ*µm within the wavenumber range considered. The use of the proposed reflective optics for focusing reduces the chromatic aberration and increases image quality (measured by the Strehl ratio (SR)). The complete system will provide clinicians a powerful tool for real-time diagnosis, treatment, and guidance in surgery with high image quality for in-vivo applications.


Assuntos
Óptica e Fotônica , Tomografia de Coerência Óptica , Cintilografia
6.
Sensors (Basel) ; 21(19)2021 Oct 03.
Artigo em Inglês | MEDLINE | ID: mdl-34640923

RESUMO

We report a statistical approach to model the resonant peak wavelength (RPW) equation(s) of a photonic crystal fibre (PCF)-based surface plasmon resonance (SPR) sensors in terms of the PCF structural parameters (air-hole diameter, pitch, core diameter and gold layer thickness) at various tolerance levels. Design of experiments (statistical tool) is used to investigate the role played by the PCF structural parameters for sensing performance evaluation-RPW, across three tolerance levels (±2%, ±5% and ±10%). Pitch of the hollow-core PCF was discovered to be the major influencing parameter for the sensing performance (RPW) of the PCF-based SPR sensor while the inner metal (gold) layer thickness and core diameter are the least contributing parameters. This novel statistical method to derive the sensing performance parameter(s) of the PCF-based SPR sensors can be applied effectively and efficiently in the designing, characterisation, tolerance analysis not only at the research level, but also in optical fibre sensor fabrication industry to improve efficiency and lower cost.


Assuntos
Óptica e Fotônica , Ressonância de Plasmônio de Superfície , Ouro , Fibras Ópticas , Fótons
7.
Sensors (Basel) ; 21(19)2021 Oct 06.
Artigo em Inglês | MEDLINE | ID: mdl-34640954

RESUMO

Photothermal heaters are important devices for optical switches and memories based on the thermo-optic/magneto-optic effect and phase change materials. We demonstrated photothermal heating in Si plasmonic waveguides loaded with Co thin films by measuring the resistance change upon inputting transverse-magnetic (TM) mode light. Temperature rise is proportional to the light intensity with clear polarization dependence. The photothermal conversion efficiency was estimated at 36 K/mW and maximum temperature rise was estimated at 221 K at steady state upon the inputting 6.3 mW TM mode light for the 400 nm-wide, 8 µm-long and 189 nm-thick Co film deposited on the Si wire waveguide with 129 nm-thick SiO2 buffer layer. The method to increase the efficiency is discussed based on the experimental and simulation results considering the thickness of the SiO2 buffer layer, Co layer and Si core layer, waveguide width, and wavelength. Local photothermal heaters in this study can be applied to a variety of fields including optical switches/memories without electrical control signals in photonic integrated circuits, on-chip optical sensors, and a lab-on-a-chip in biology, chemistry, and medicine.


Assuntos
Calefação , Dióxido de Silício , Simulação por Computador , Dispositivos Lab-On-A-Chip , Óptica e Fotônica
8.
BMC Ophthalmol ; 21(1): 364, 2021 Oct 13.
Artigo em Inglês | MEDLINE | ID: mdl-34645396

RESUMO

BACKGROUND: To evaluate the effects of pretreatment for dry eye disease (DED) on the accuracy of intraocular lens (IOL) power calculation. METHODS: Patients who underwent uneventful cataract surgery were included in the study. IOL power was determined using the SRK/T and Barrett Universal II (Barrett) formulas. The patients were divided into non-pretreatment and pretreatment groups, and those in the pretreatment group were treated with topical 0.5% loteprednol etabonate and 0.05% cyclosporin A for 2 weeks prior to cataract surgery. Ocular biometry was performed in all groups within 2 days before surgery. The mean prediction error, mean absolute error (MAE), and proportions of refractive surprise were compared between the non-pretreatment and pretreatment groups at 1 month postoperatively. Refractive surprise was defined as MAE ≥ 0.75D. RESULTS: In a total of 105 patients, 52 (52 eyes) were in the non-pretreatment group and 53 (53 eyes) in the pretreatment group. The MAE was 0.42 ± 0.33, 0.38 ± 0.34 (SRK/T, Barrett) and 0.23 ± 0.19, 0.24 ± 0.19 in the non-pretreatment and pretreatment groups, respectively (p < 0.001/=0.008). The number of refractive surprises was also significantly lower in the pretreatment group. [non-pretreatment/pretreatment: 9/2 (SRK/T); 8/1 (Barrett); p = 0.024/0.016]. Pretreatment of DED was related to a reduction in postoperative refractive surprise. [SRK/T/Barrett: OR = 0.18/0.17 (95% CI: 0.05-0.71/0.05-0.60), p = 0.014/0.006]. CONCLUSIONS: The accuracy of IOL power prediction can be increased by actively treating DED prior to cataract surgery.


Assuntos
Síndromes do Olho Seco , Lentes Intraoculares , Facoemulsificação , Biometria , Humanos , Implante de Lente Intraocular , Óptica e Fotônica , Refração Ocular , Estudos Retrospectivos
9.
Nano Lett ; 21(20): 8715-8722, 2021 10 27.
Artigo em Inglês | MEDLINE | ID: mdl-34643401

RESUMO

Optical Fourier transform-based processing is an attractive technique due to the fast processing times and large-data rates. Furthermore, it has recently been demonstrated that certain Fourier-based processors can be realized in compact form factors using flat optics. The flat optics, however, have been demonstrated as static filters where the operator is fixed, limiting the applicability of the approach. Here, we demonstrate a reconfigurable metasurface that can be dynamically tuned to provide a range of processing modalities including bright-field imaging, low-pass and high-pass filtering, and second-order differentiation. The dynamically tunable metasurface can be directly combined with standard coherent imaging systems and operates with a numerical aperture up to 0.25 and over a 60 nm bandwidth. The ability to dynamically control light in the wave vector domain, while doing so in a compact form factor, may open new doors to applications in microscopy, machine vision, and sensing.


Assuntos
Processamento de Imagem Assistida por Computador , Óptica e Fotônica , Microscopia
10.
Nano Lett ; 21(20): 8602-8608, 2021 10 27.
Artigo em Inglês | MEDLINE | ID: mdl-34662137

RESUMO

Structural coloration is a recurring solution in biological systems to control visible light. In nature, basic structural coloration results from light interacting with a repetitive nanopattern, but more complex interactions and striking results are achieved by organisms incorporating additional hierarchical structures. Artificial reproduction of single-level structural color has been achieved using repetitive nanostructures, with flat sheets of inverse opals being very popular because of their simple and reliable fabrication process. Here, we control photonic structures at several length scales using a combination of direct laser writing and nanosphere assembly, producing freeform hierarchical constructions of inverse opals with high-intensity structural coloration. We report the first 3D prints of stacked, overhanging and slanted microstructures of inverse opals. Among other characteristics, these hierarchical photonic structures exhibit geometrically tunable colors, focal-plane-dependent patterns, and arbitrary alignment of microstructure facet with self-assembled lattice. Based on those results, novel concepts of multilevel information encoding systems are presented.


Assuntos
Nanoestruturas , Fótons , Luz , Óptica e Fotônica , Impressão Tridimensional
11.
J Cataract Refract Surg ; 47(11): 1423-1429, 2021 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-34675149

RESUMO

PURPOSE: To investigate the accuracy of intraocular lens (IOL) formulas for the prediction of postoperative refraction in lens subluxation in Marfan syndrome. SETTING: Eye and ENT Hospital of Fudan University, Shanghai, China. DESIGN: Consecutive retrospective clinical observational case series. METHODS: 60 eligible eyes with lens subluxation from 39 young patients with Marfan syndrome (8.53 ± 4.38 years) underwent phacoemulsification combined with single-eyelet modified capsular tension ring (MCTR) and IOL implantation. The prediction error values with mean zero out (relative prediction error) and their absolute values (AE) were calculated. RESULTS: Generally, the SRK/T formula with Wang-Koch (WK) adjustment had the lowest median AE at 0.418 diopters (D), and the Holladay 1 with WK adjustment had the lowest mean AE at 0.499 D. The median AE of the other 10 formulas, in order from lowest to highest, were Haigis with WK (0.494 D), Holladay 1 with WK (0.495 D), Hoffer Q with WK (0.508 D), Haigis (0.525 D), T2 (0.542 D), Hoffer Q (0.624 D), SRK/T and Holladay 1 (0.660 D), Super (0.680 D), and Barrett Universal II (0.714 D) formulas. Haigis formula was found to be statistically significantly different from SRK/T, Holladay 1, and Barrett Universal II (all 3 P < .001) but not Hoffer Q (P = .236) formula. CONCLUSIONS: The Haigis formula was recommended for young Marfan lens subluxation patients with in-the-bag IOLs and scleral-sutured single-eyelet MCTR implantation. WK adjustments were successful in those cases where the axial length was longer than 25.0 mm.


Assuntos
Subluxação do Cristalino , Lentes Intraoculares , Síndrome de Marfan , Facoemulsificação , Biometria , Criança , Pré-Escolar , China , Humanos , Implante de Lente Intraocular , Síndrome de Marfan/complicações , Óptica e Fotônica , Refração Ocular , Estudos Retrospectivos
12.
J Biomed Opt ; 26(9)2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34595886

RESUMO

SIGNIFICANCE: An increasing interest in the area of biological effects at exposure of tissues and cells to the terahertz (THz) radiation is driven by a rapid progress in THz biophotonics, observed during the past decades. Despite the attractiveness of THz technology for medical diagnosis and therapy, there is still quite limited knowledge about safe limits of THz exposure. Different modes of THz exposure of tissues and cells, including continuous-wave versus pulsed radiation, various powers, and number and duration of exposure cycles, ought to be systematically studied. AIM: We provide an overview of recent research results in the area of biological effects at exposure of tissues and cells to THz waves. APPROACH: We start with a brief overview of general features of the THz-wave-tissue interactions, as well as modern THz emitters, with an emphasis on those that are reliable for studying the biological effects of THz waves. Then, we consider three levels of biological system organization, at which the exposure effects are considered: (i) solutions of biological molecules; (ii) cultures of cells, individual cells, and cell structures; and (iii) entire organs or organisms; special attention is devoted to the cellular level. We distinguish thermal and nonthermal mechanisms of THz-wave-cell interactions and discuss a problem of adequate estimation of the THz biological effects' specificity. The problem of experimental data reproducibility, caused by rareness of the THz experimental setups and an absence of unitary protocols, is also considered. RESULTS: The summarized data demonstrate the current stage of the research activity and knowledge about the THz exposure on living objects. CONCLUSIONS: This review helps the biomedical optics community to summarize up-to-date knowledge in the area of cell exposure to THz radiation, and paves the ways for the development of THz safety standards and THz therapeutic applications.


Assuntos
Óptica e Fotônica , Radiação Terahertz , Reprodutibilidade dos Testes
13.
Nat Methods ; 18(10): 1259-1264, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34608309

RESUMO

Understanding complex biological systems requires visualizing structures and processes deep within living organisms. We developed a compact adaptive optics module and incorporated it into two- and three-photon fluorescence microscopes, to measure and correct tissue-induced aberrations. We resolved synaptic structures in deep cortical and subcortical areas of the mouse brain, and demonstrated high-resolution imaging of neuronal structures and somatosensory-evoked calcium responses in the mouse spinal cord at great depths in vivo.


Assuntos
Neuroimagem/métodos , Óptica e Fotônica/métodos , Animais , Proteínas de Bactérias , Embrião não Mamífero , Feminino , Proteínas de Fluorescência Verde , Proteínas Luminescentes , Masculino , Camundongos , Peixe-Zebra
14.
J Photochem Photobiol B ; 223: 112283, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34537542

RESUMO

BACKGROUND: In vitro and in vivo testing of new technology was performed to evaluate the antiplasmodial activity of Photonic Multiphase Modulators (PMM) in cultures and in mice previously infected with Plasmodium falciparum and Plasmodium berghei parasites. METHODS: Cultures of P. falciparum infected-erythrocytes were exposed overnight to two generations of different APSE™ and BioPhoton-X™ PMM (C#1, R#1, R#2, D8 and D9). Growth of parasites was determined through flow cytometry or microscopy. Mice of the strain C57BL/6 were infected and treated with water exposed to second-generation APSE™ and BioPhoton-X™ PMM plus one previously untested first-generation PMM (AGN10). Parasitemia and weight loss were monitored throughout the infection until death or point of euthanasia was reached. After death, necropsy was performed on all animals and the number of days each survived was recorded. RESULTS: In vitro and in vivo testing using different APSE™- and BioPhoton-X™-designed PMM revealed an effect of D8 in lowering the growth of the parasite in vitro, while the best effect in mice was observed with D9 PMM, with a reduced weight loss and an increase in survival, although the results in lowering the parasitemia were inconclusive. D9 PMM did not generate ROS in vitro. CONCLUSIONS: APSE™ and BioPhoton-X™ optic circuit technologies can affect the growth of parasites and show protective effects in mice drinking from water treated with their PMM.


Assuntos
Antimaláricos/química , Água/química , Animais , Antimaláricos/farmacologia , Antimaláricos/uso terapêutico , Eritrócitos/parasitologia , Malária/tratamento farmacológico , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Óptica e Fotônica/métodos , Plasmodium berghei/efeitos dos fármacos , Plasmodium berghei/metabolismo , Plasmodium falciparum/efeitos dos fármacos , Plasmodium falciparum/metabolismo , Espécies Reativas de Oxigênio/metabolismo
15.
Sensors (Basel) ; 21(18)2021 Sep 16.
Artigo em Inglês | MEDLINE | ID: mdl-34577421

RESUMO

Measuring the underwater light field is a key mission of the international Biogeochemical-Argo program. Since 2012, 0-250 dbar profiles of downwelling irradiance at 380, 412 and 490 nm besides photosynthetically available radiation (PAR) have been acquired across the globe every 1 to 10 days. The resulting unprecedented amount of radiometric data has been previously quality-controlled for real-time distribution and ocean optics applications, yet some issues affecting the accuracy of measurements at depth have been identified such as changes in sensor dark responsiveness to ambient temperature, with time and according to the material used to build the instrument components. Here, we propose a quality-control procedure to solve these sensor issues to make Argo radiometry data available for delayed-mode distribution, with associated error estimation. The presented protocol requires the acquisition of ancillary radiometric measurements at the 1000 dbar parking depth and night-time profiles. A test on >10,000 profiles from across the world revealed a quality-control success rate >90% for each band. The procedure shows similar performance in re-qualifying low radiometry values across diverse oceanic regions. We finally recommend, for future deployments, acquiring daily 1000 dbar measurements and one night profile per year, preferably during moonless nights and when the temperature range between the surface and 1000 dbar is the largest.


Assuntos
Óptica e Fotônica , Radiometria , Oceanos e Mares , Controle de Qualidade , Temperatura
16.
J Refract Surg ; 37(9): 609-615, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34506237

RESUMO

PURPOSE: To evaluate whether intraoperative aberrometry improves the accuracy of refractive outcomes after cataract surgery in highly myopic, highly hyperopic, and post-refractive eyes. METHODS: This single-center, retrospective review compared the spherical equivalent of postoperative refraction to that predicted by the Barrett Universal II formula versus Optiwave Refractive Analysis (ORA) (Alcon Laboratories, Inc) for highly myopic and hyperopic eyes and to the Barrett True K formula versus ORA for post-refractive eyes. The number and magnitude of lens changes were analyzed and used to determine in how many cases refractive surprises were affected by ORA, with additional subanalysis of outcomes based on average keratometry values. RESULTS: ORA led to a change in the lens power implanted in 48% (96 of 198) of eyes, and prevented hyperopic surprise in 27% (15 of 55) and excess myopia in 46% (19 of 41). Steeper keratometry values correlated with more frequent changes on ORA-recommended implanted intraocular lens (P = .0031). ORA led to a similar percentage of eyes falling within ±0.50, ±0.75, and ±1.00 diopters compared to the Barrett Universal II and Barrett True K formulas. In post-refractive eyes, ORA led to a similar mean absolute error when compared to the Barrett True K formula (P = .62). For highly myopic eyes with an axial length of greater than 27 mm, ORA demonstrated a trend toward lower mean absolute error when compared to the Barrett Universal II formula (P = .076). CONCLUSIONS: ORA demonstrated similar refractive results to the Barrett True K formula in post-refractive eyes and to the Barrett Universal II formula in highly myopic and hyper-opic eyes and may provide additional benefit for eyes with steeper corneas or an axial length of greater than 27 mm. [J Refract Surg. 2021;37(9):609-615.].


Assuntos
Lentes Intraoculares , Miopia , Facoemulsificação , Aberrometria , Biometria , Humanos , Miopia/cirurgia , Óptica e Fotônica , Refração Ocular , Estudos Retrospectivos
17.
Nature ; 597(7875): 185-186, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34497387
18.
Sensors (Basel) ; 21(17)2021 Aug 31.
Artigo em Inglês | MEDLINE | ID: mdl-34502753

RESUMO

While mRNA vaccines have been well-studied in vitro and in animals prior to their use in the human population during the Covid-19 pandemic, their exact mechanisms of inducing immunity are still being elucidated. The large-scale collection of data necessary to fully understand these mechanisms, and their variability across heterogeneous populations, requires rapid diagnostic tests that accurately measure the various biomarkers involved in the immune response following vaccination. Recently, our lab developed a novel "Disposable Photonics" platform for rapid, label-free, scalable diagnostics that utilizes photonic ring resonator sensor chips combined with plastic micropillar cards able to provide passive microfluidic flow. Here, we demonstrate the utility of this system in confirming the presence of SARS-CoV-2 spike protein in the serum of recently vaccinated subjects, as well as tracking a post-vaccination rise in anti-SARS-CoV-2 antibodies. A maximum concentration in SARS-CoV-2 spike protein was detected one day after vaccination and was reduced below detectable levels within 10 days. This highlights the applicability of our rapid photonic sensor platform for acquiring the data necessary to understand vaccine mechanisms on a large scale, as well as individual patient responses to SARS-CoV-2 mRNA vaccines.


Assuntos
Técnicas Biossensoriais , Vacinas contra COVID-19 , Glicoproteína da Espícula de Coronavírus , Anticorpos Antivirais , COVID-19 , Humanos , Óptica e Fotônica , Pandemias , SARS-CoV-2 , Vacinação
19.
Nat Commun ; 12(1): 5509, 2021 09 17.
Artigo em Inglês | MEDLINE | ID: mdl-34535656

RESUMO

Traditional 3D printing based on Digital Light Processing Stereolithography (DLP-SL) is unnecessarily limiting as applied to microfluidic device fabrication, especially for high-resolution features. This limitation is due primarily to inherent tradeoffs between layer thickness, exposure time, material strength, and optical penetration that can be impossible to satisfy for microfluidic features. We introduce a generalized 3D printing process that significantly expands the accessible spatially distributed optical dose parameter space to enable the fabrication of much higher resolution 3D components without increasing the resolution of the 3D printer. Here we demonstrate component miniaturization in conjunction with a high degree of integration, including 15 µm × 15 µm valves and a 2.2 mm × 1.1 mm 10-stage 2-fold serial diluter. These results illustrate our approach's promise to enable highly functional and compact microfluidic devices for a wide variety of biomolecular applications.


Assuntos
Microfluídica , Miniaturização , Óptica e Fotônica , Impressão Tridimensional , Membranas , Pressão , Microtomografia por Raio-X
20.
Nano Lett ; 21(18): 7602-7608, 2021 09 22.
Artigo em Inglês | MEDLINE | ID: mdl-34468150

RESUMO

Two-dimensional transition metal dichalcogenides are promising candidates for ultrathin light modulators due to their highly tunable excitonic resonances at visible and near-infrared wavelengths. At cryogenic temperatures, large excitonic reflectivity in monolayer molybdenum diselenide (MoSe2) has been shown, but the permittivity and index modulation have not been studied. Here, we demonstrate large gate-tunability of complex refractive index in monolayer MoSe2 by Fermi level modulation and study the doping dependence of the A and B excitonic resonances for temperatures between 4 and 150 K. By tuning the charge density, we observe both temperature- and carrier-dependent epsilon-near-zero response in the permittivity and transition from metallic to dielectric near the A exciton energy. We attribute the dynamic control of the refractive index to the interplay between radiative and non-radiative decay channels that are tuned upon gating. Our results suggest the potential of monolayer MoSe2 as an active material for emerging photonics applications.


Assuntos
Molibdênio , Elementos de Transição , Óptica e Fotônica , Refratometria , Temperatura
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