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A system for probing Casimir energy corrections to the condensation energy

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Microsystems & Nanoengineering 2020年第1期6卷 1-12页

作者： Diego Perez-Morelo Alexander Stange Richard W.Lally Lawrence K.Barrett Matthias Imboden Abhishek Som David K.Campbell vladimir A.aksyuk David J.Bishop Department of ECE Boston UniversityBostonMA 02215USA Physical Measurement Laboratory National Institute of Standards and TechnologyGaithersburgMD 20899USA Institute for Research in Electronics and Applied Physics&Maryland NanoCenter University of MarylandCollege ParkMD 20742USA Division of MSE Boston UniversityBostonMA 02215 USA 54K-MEMS Sarl Rue des Lavannes 172072 St BlaiseSwitzerland Department of Physics Boston UniversityBostonMA 02215USA Department of ME Boston UniversityBostonMA 02215USA Department of BME Boston UniversityBostonMA 02215USA

In this article,we present a nanoelectromechanical system(NEMS)designed to detect changes in the Casimir *** Casimir effect is a result of the appearance of quantum fluctuations in an electromagnetic *** experiments have used nano-or microscale parallel plate capacitors to detect the Casimir force by measuring the small attractive force these fluctuations exert between the two *** this new set of experiments,we aim to directly detect the shifts in the Casimir energy in a vacuum due to the presence of the metallic parallel plates,one of which is a superconductor.A change in the Casimir energy of this configuration is predicted to shift the superconducting transition temperature(T_(c))because of the interaction between it and the superconducting condensation *** our experiment,we take a superconducting film,carefully measure its transition temperature,bring a conducting plate close to the film,create a Casimir cavity,and then measure the transition temperature *** expected shifts are smaller than the normal shifts one sees in cycling superconducting films to cryogenic temperatures,so using a NEMS resonator in situ is the only practical way to obtain accurate,reproducible *** a thin Pb film and opposing Au surface,we observe no shift in T_(c)>12µK down to a minimum spacing of~70 nm at zero applied magnetic field.

关键词： cycling energy film

Photonic waveguide to free-space Gaussian beam extreme mode converter

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Light(Science & Applications) 2018年第1期7卷 346-358页

作者： Sangsik Kim Daron A.Westly Brian J.Roxworthy Qing Li Alexander Yulaev Kartik Srinivasan vladimir A.aksyuk Center for Nanoscale Science and Technology National Institute of Standards and TechnologyGaithersburgMD 20899USA Maryland Nanocenter University of MarylandCollege ParkMD 20742USA Department of Electrical and Computer Engineering Texas Tech UniversityLubbockTX 79409USA

Integration of photonic chips with millimeter-scale atomic,micromechanical,chemical,and biological systems can advance science and enable new miniaturized hybrid devices and *** interaction via small evanescent volumes restricts performance in applications such as gas spectroscopy,and a general ability to photonically access optical fields in large free-space volumes is ***,conventional inverse tapers and grating couplers do not directly scale to create wide,high-quality collimated beams for low-loss diffraction-free propagation over many millimeters in free space,necessitating additional bulky collimating optics and expensive ***,we develop an extreme mode converter,which is a compact planar photonic structure that efficiently couples a 300 nm×250 nm silicon nitride high-index single-mode waveguide to a well-collimated near surface-normal Gaussian beam with an≈160μm waist,which corresponds to an increase in the modal area by a factor of>*** beam quality is thoroughly characterized,and propagation over 4mm in free space and coupling back into a single-mode photonic waveguide with low loss via a separate identical mode converter is *** achieve low phase error over a beam area that is>100×larger than that of a typical grating coupler,our approach separates the two-dimensional mode expansion into two sequential separately optimized stages,which create a fully expanded and well-collimated Gaussian slab mode before out-coupling it into free *** at 780 nm for integration with chip-scale atomic vapor cell cavities,our design can be adapted for visible,telecommunication,or other *** technique can be expanded to more arbitrary phase and intensity control of both large-diameter,free-space optical beams and wide photonic slab modes.

关键词： waveguide millimeter mode

Transfer of motion through a microelectromechanical linkage at nanometer and microradian scales

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Microsystems & Nanoengineering 2016年第1期2卷 106-115页

作者： Craig R.Copeland Craig D.McGray Jon Geist vladimir A.aksyuk Samuel M.Stavis Center for Nanoscale Science and Technology National Institute of Standards and TechnologyGaithersburgMD 20899USA Maryland Nanocenter University of MarylandCollege ParkMD 20742USA Engineering Physics Division National Institute of Standards and TechnologyGaithersburgMD 20899USA Modern Microsystems Silver SpringMD 20904USA

Mechanical linkages are fundamentally important for the transfer of motion through assemblies of parts to perform *** their behavior in macroscale systems is well understood,there are open questions regarding the performance and reliability of linkages with moving parts in contact within microscale *** challenges impede experimental studies to answer such *** this study,we develop a novel combination of optical microscopy methods that enable the first quantitative measurements at nanometer and microradian scales of the transfer of motion through a microelectromechanical *** track surface features and fluorescent nanoparticles as optical indicators of the motion of the underlying parts of the *** models allow precise characterization of the electrothermal actuation of the *** transfer of motion between translating and rotating links can be nearly ideal,depending on the operating *** coupling and decoupling of the links agree with an ideal kinematic model to within approximately 5%,and the rotational output is perfectly repeatable to within approximately 20 ***,stiction can result in nonideal kinematics,and input noise on the scale of a few millivolts produces an asymmetric interaction of electrical noise and mechanical play that results in the nondeterministic transfer of *** study establishes a new approach towards testing the performance and reliability of the transfer of motion through assemblies of microscale parts,opening the door to future studies of complex microsystems.

关键词： Electrothermal linkage microelectromechanical nanoparticle noise rotation tracking translation

Integrating planar photonics for multi-beam generation and atomic clock packaging on chip

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Light(Science & Applications) 2023年第4期12卷 691-701页

作者： Chad Ropp Wenqi Zhu Alexander Yulaev Daron Westly Gregory Simelgor Akash Rakholia William Lunden Dan Sheredy Martin MBoyd Scott Papp Amit Agrawal vladimir aksyuk Physical Measurement Laboratory National Institute of Standards and TechnologyGaithersburgMD 20899USA Department of Chemistry and Biochemistry University of MarylandCollege ParkMD 20742USA Vector Atomic Inc.PleasantonCA 94588USA Physical Measurement Laboratory National Institute of Standards and TechnologyBoulderCO 80305USA

The commercialization of atomic technologies requires replacing laboratory-scale laser setups with compact and manufacturable optical *** arrangements of free-space beams can be generated on chip through a combination of integrated photonics and metasurface *** this work,we combine these two technologies using flip-chip bonding and demonstrate an integrated optical architecture for realizing a compact strontium atomic *** planar design includes twelve beams in two co-aligned magneto-optical *** beams are directed above the chip to intersect at a central location with diameters as large as 1 *** design also includes two co-propagating beams at lattice and clock *** beams emit collinearly and vertically to probe the center of the magneto-optical trap,where they will have diameters of≈100μ*** these devices we demonstrate that our integrated photonic platform is scalable to an arbitrary number of beams,each with different wavelengths,geometries,and polarizations.

关键词： planar diameters atomic

Subnanometer localization accuracy in widefield optical microscopy

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Light(Science & Applications) 2018年第1期7卷 740-754页

作者： Craig R.Copeland Jon Geist Craig D.McGray vladimir A.aksyuk J.Alexander Liddle B.Robert Ilic Samuel M.Stavis Center for Nanoscale Science and Technology National Institute of Standards and TechnologyGaithersburgMD 20899USA Maryland NanoCenter University of MarylandCollege ParkMD 20742USA Engineering Physics Division National Institute of Standards and TechnologyGaithersburgMD 20899USA

The common assumption that precision is the limit of accuracy in localization microscopy and the typical absence of comprehensive calibration of optical microscopes lead to a widespread issue—overconfidence in measurement results with nanoscale statistical uncertainties that can be invalid due to microscale systematic *** this article,we report a comprehensive solution to this underappreciated *** develop arrays of subresolution apertures into the first reference materials that enable localization errors approaching the atomic scale across a submillimeter *** present novel methods for calibrating our microscope system using aperture arrays and develop aberration corrections that reach the precision limit of our reference *** correct and register localization data from multiple colors and test different sources of light emission with equal accuracy,indicating the general applicability of our reference materials and calibration *** a first application of our new measurement capability,we introduce the concept of critical-dimension localization microscopy,facilitating tests of nanofabrication processes and quality control of aperture *** a second application,we apply these stable reference materials to answer open questions about the apparent instability of fluorescent nanoparticles that commonly serve as fiducial *** study establishes a foundation for subnanometer localization accuracy in widefield optical microscopy.

关键词： optical limit field