Results for "Steven G. Johnson"

total 107337took 0.13s
Saddle-point integration of $C_\infty$ "bump" functionsAug 18 2015This technical note describes the application of saddle-point integration to the asymptotic Fourier analysis of the well-known $C_\infty$ "bump" function $\exp[-(1-x^2)^{-1}]$, deriving both the asymptotic decay rate $k^{-3/4} \exp(-\sqrt k)$ of the Fourier ... More
Numerical methods for computing Casimir interactionsJul 03 2010Oct 01 2010We review several different approaches for computing Casimir forces and related fluctuation-induced interactions between bodies of arbitrary shapes and materials. The relationships between this problem and well known computational techniques from classical ... More
Is the electrostatic force between a point charge and a neutral metallic object always attractive?Jul 13 2010We give an example of a geometry in which the electrostatic force between a point charge and a neutral metallic object is repulsive. The example consists of a point charge centered above a thin metallic hemisphere, positioned concave up. We show that ... More
Efficient generation of correlated random numbers using Chebyshev-optimal magnitude-only IIR filtersMar 15 2007Apr 14 2007We compare several methods for the efficient generation of correlated random sequences (colored noise) by filtering white noise to achieve a desired correlation spectrum. We argue that a class of IIR filter-design techniques developed in the 1970s, which ... More
Electromagnetic Wave Source ConditionsJan 23 2013This chapter discusses the relationships between current sources and the resulting electromagnetic waves in FDTD simulations. First, the "total-field/scattered-field" approach to creating incident plane waves is reviewed and seen to be a special case ... More
Type-II/III DCT/DST algorithms with reduced number of arithmetic operationsMar 30 2007Jan 29 2009We present algorithms for the discrete cosine transform (DCT) and discrete sine transform (DST), of types II and III, that achieve a lower count of real multiplications and additions than previously published algorithms, without sacrificing numerical ... More
Optical "Bernoulli" forcesMay 02 2013Sep 12 2013By Bernoulli's law, an increase in the relative speed of a fluid around a body is accompanies by a decrease in the pressure. Therefore, a rotating body in a fluid stream experiences a force perpendicular to the motion of the fluid because of the unequal ... More
Type-IV DCT, DST, and MDCT algorithms with reduced numbers of arithmetic operationsAug 31 2007Jan 29 2009We present algorithms for the type-IV discrete cosine transform (DCT-IV) and discrete sine transform (DST-IV), as well as for the modified discrete cosine transform (MDCT) and its inverse, that achieve a lower count of real multiplications and additions ... More
Scalable computation of Jordan chainsApr 19 2017Apr 24 2017We present an algorithm to compute the Jordan chain of a nearly defective matrix with a $2\times2$ Jordan block. The algorithm is based on an inverse-iteration procedure and only needs information about the invariant subspace corresponding to the Jordan ... More
Efficient Computation of Power, Force, and Torque in BEM Scattering CalculationsJul 11 2013We present concise, computationally efficient formulas for several quantities of interest -- including absorbed and scattered power, optical force (radiation pressure), and torque -- in scattering calculations performed using the boundary-element method ... More
Perturbation theory for anisotropic dielectric interfaces, and application to sub-pixel smoothing of discretized numerical methodsAug 07 2007We derive a correct first-order perturbation theory in electromagnetism for cases where an interface between two anisotropic dielectric materials is slightly shifted. Most previous perturbative methods give incorrect results for this case, even to lowest ... More
Speed-of-light limitations in passive linear mediaMay 01 2014We prove that well-known speed of light restrictions on electromagnetic energy velocity can be extended to a new level of generality, encompassing even nonlocal chiral media in periodic geometries, while at the same time weakening the underlying assumptions ... More
Repulsive, nonmonotonic Casimir forces in a glide-symmetric geometryFeb 11 2008We describe a three-dimensional geometry that exhibits a repulsive Casimir force using ordinary metallic materials, as computed via an exact numerical method (no uncontrolled approximations). The geometry consists of a zippelike, glide-symmetric structure ... More
Sideways adiabaticity: Beyond ray optics for slowly varying metasurfacesJun 14 2018Nov 14 2018Optical metasurfaces (subwavelength-patterned surfaces typically described by variable effective surface impedances) are typically modeled by an approximation akin to ray optics: the reflection or transmission of an incident wave at each point of the ... More
Transformation Inverse DesignApr 04 2013May 22 2013We present a new technique for the design of transformation-optics devices based on large-scale optimization to achieve the optimal effective isotropic dielectric materials within prescribed index bounds, which is computationally cheap because transformation ... More
General scaling limitations of ground-plane and isolated-object cloaksFeb 18 2011Aug 11 2011We prove that, for arbitrary three-dimensional transformation-based invisibility cloaking of an object above a ground plane or of isolated object, there are practical constraints that increase with the object size. In particular, we show that the cloak ... More
Fluctuation-Induced Phenomena in Nanoscale Systems: Harnessing the Power of NoiseJul 17 2012Jul 19 2012The famous Johnson-Nyquist formula relating noise current to conductance has a microscopic generalization relating noise current density to microscopic conductivity, with corollary relations governing noise in the components of the electromagnetic fields. ... More
Rigorous sufficient conditions for index-guided mode in microstructured dielectric waveguidesMar 19 2008We derive a sufficient condition for the existence of index-guided modes in a very general class of dielectric waveguides, including photonic-crystal fibers (arbitrary periodic claddings, such as ``holey fibers''), anisotropic materials, and waveguides ... More
Fluctuating surface-current formulation of radiative heat transfer: theory and applicationsApr 04 2013We describe a novel fluctuating-surface current formulation of radiative heat transfer between bodies of arbitrary shape that exploits efficient and sophisticated techniques from the surface-integral-equation formulation of classical electromagnetic scattering. ... More
Radiative heat transfer in nonlinear Kerr mediaJun 16 2014Feb 24 2015We obtain a fluctuation--dissipation theorem describing thermal electromagnetic fluctuation effects in nonlinear media that we exploit in conjunction with a stochastic Langevin framework to study thermal radiation from Kerr ($\chi^{(3)}$) photonic cavities ... More
Computation of Casimir Interactions between Arbitrary 3D Objects with Arbitrary Material PropertiesOct 26 2010Oct 20 2011We extend a recently introduced method for computing Casimir forces between arbitrarily--shaped metallic objects [M. T. H. Reid et al., Phys. Rev. Lett._103_ 040401 (2009)] to allow treatment of objects with arbitrary material properties, including imperfect ... More
Topology optimization of freeform large-area metasurfacesFeb 08 2019We demonstrate optimization of optical metasurfaces over $10^5$--$10^6$ degrees of freedom in two and three dimensions, 100--1000+ wavelengths ($\lambda$) in diameter, with 100+ parameters per $\lambda^2$. In particular, we show how topology optimization, ... More
An improved beam waist formula for ultrashort, tightly-focused linearly, radially, and azimuthally polarized laser pulses in free spaceNov 22 2013Feb 25 2014We derive an asymptotically accurate formula for the beam waist of ultrashort, tightly-focused fundamental linearly-polarized, radially-polarized, and azimuthally-polarized modes in free space. We compute the exact beam waist via numerical cubature to ... More
Design of diamond microcavities for single photon frequency down-conversionApr 07 2015Apr 10 2015We propose monolithic diamond cavities that can be used to convert color-center Fock-state single photons from emission wavelengths to telecommunication bands. We present a detailed theoretical description of the conversion process, analyzing important ... More
Shape-Independent Limits to Near-Field Radiative Heat TransferApr 06 2015Oct 14 2015We derive shape-independent limits to the spectral radiative heat-transfer rate between two closely spaced bodies, generalizing the concept of a black body to the case of near-field energy transfer. Through conservation of energy and reciprocity, we show ... More
The effectiveness of thin films in lieu of hyperbolic metamaterials in the near fieldNov 22 2013Jan 29 2014We show that the near-field functionality of hyperbolic metamaterials (HMM), typically proposed for increasing the photonic local density of states (LDOS), can be achieved with thin metal films. Although HMMs have an infinite density of internally-propagating ... More
Fluctuating surface-current formulation of radiative heat transfer for arbitrary geometriesJun 07 2012Jul 03 2012We describe a fluctuating surface-current formulation of radiative heat transfer, applicable to arbitrary geometries, that directly exploits standard, efficient, and sophisticated techniques from the boundary-element method. We validate as well as extend ... More
Design of thin-film photonic metamaterial Lüneburg lens using analytical approachNov 17 2011We design an all-dielectric L\"uneburg lens as an adiabatic space-variant lattice explicitly accounting for finite film thickness. We describe an all-analytical approach to compensate for the finite height of subwavelength dielectric structures in the ... More
Delay-bandwidth and delay-loss limitations for cloaking of large objectsMar 30 2010Jun 14 2010Based on a simple model of ground-plane cloaking, we argue that the diffculty of cloaking is fundamentally limited by delay-loss and delaylbandwidth/size limitations that worsen as the size of the object to be cloaked increases relative to the wavelength. ... More
Chi2 and chi3 harmonic generation at a critical power in inhomogeneous doubly resonant cavitiesMay 24 2007We derive general conditions for 100 percent frequency conversion in any doubly resonant nonlinear cavity, for both second- and third-harmonic generation via chi2 and chi3 nonlinearities. We find that conversion efficiency is optimized for a certain critical ... More
Fluctuating Surface Currents: A New Algorithm for Efficient Prediction of Casimir Interactions among Arbitrary Materials in Arbitrary Geometries. I. TheoryMar 01 2012Jul 12 2012This paper presents a new method for the efficient numerical computation of Casimir interactions between objects of arbitrary geometries, composed of materials with arbitrary frequency-dependent electrical properties. Our method formulates the Casimir ... More
Generalized Taylor-Duffy Method for Efficient Evaluation of Galerkin Integrals in Boundary-Element Method ComputationsDec 05 2013Jul 19 2014We present a generic technique, automated by computer-algebra systems and available as open-source software \cite{scuff-em}, for efficient numerical evaluation of a large family of singular and nonsingular 4-dimensional integrals over triangle-product ... More
Theory of Magnetic Seed-Field Theory of Magnetic Seed-Field Generation during the Cosmological First-Order Electroweak Phase TransitionJan 20 2010We present a theory of the generation of magnetic seed fields in bubble collisions during a first-order electroweak phase transition (EWPT) possible for some choices of parameters in the minimal supersymmetric Standard Model. The theory extends earlier ... More
Magnetic Seed Field Generation from Electroweak Bubble Collisions, with Bubble Walls of Finite ThicknessMar 12 2009Nov 01 2009Building on earlier work, we develop an equation-of-motion method for calculating magnetic seed fields generated from currents arising from charged W fields in bubble collisions during a first-order primordial electroweak phase transition allowed in some ... More
Secondary ionization and heating by fast electronsOct 23 2009We examine the fate of fast electrons (with energies E>10 eV) in a thermal gas of primordial composition. To follow their interactions with the background gas, we construct a Monte Carlo model that includes: (1) electron-electron scattering (which transforms ... More
Comment on "A self-assembled three-dimensional cloak in the visible" in Scientific Reports 3, 2328Oct 05 2013M\"uhlig et. al. propose and fabricate a "cloak" comprised of nano-particles on the surface of a sub-wavelength silica sphere. However, the coating only reduces the scattered fields. This is achieved by increased absorption, such that total extinction ... More
Non-touching nanoparticle diclusters bound by repulsive and attractive Casimir forcesDec 11 2009We present a scheme for obtaining stable Casimir suspension of dielectric nontouching objects immersed in a fluid, validated here in various geometries consisting of ethanol-separated dielectric spheres and semi-infinite slabs. Stability is induced by ... More
Casimir forces in the time domain: I. TheoryApr 01 2009Apr 21 2009We introduce a method to compute Casimir forces in arbitrary geometries and for arbitrary materials based on the finite-difference time-domain (FDTD) scheme. The method involves the time-evolution of electric and magnetic fields in response to a set of ... More
Inverse design of large-area metasurfacesAug 13 2018Dec 14 2018We present a computational framework for efficient optimization-based "inverse design" of large-area "metasurfaces" (subwavelength-patterned surfaces) for applications such as multi-wavelength and multi-angle optimizations, and demultiplexers. To optimize ... More
High-efficiency degenerate four wave-mixing in triply resonant nanobeam cavitiesNov 16 2013We demonstrate high-efficiency, degenerate four-wave mixing in triply resonant Kerr $\chi^(3)$ photonic crystal (PhC) nanobeam cavities. Using a combination of temporal coupled mode theory and nonlinear finite-difference time-domain (FDTD) simulations, ... More
Quantitative test of general theories of the intrinsic laser linewidthMay 07 2015Jun 12 2015We perform a first-principles calculation of the quantum-limited laser linewidth, testing the predictions of recently developed theories of the laser linewidth based on fluctuations about the known steady-state laser solutions against traditional forms ... More
Non-intuitive Computational Optimization of Illumination Patterns for Maximum Optical Force and TorqueJan 26 2017This paper aims to maximize optical force and torque on arbitrary micro- and nano-scale objects using numerically optimized structured illumination. By developing a numerical framework for computer-automated design of 3d vector-field illumination, we ... More
Casimir repulsion beyond the dipole regimeMay 02 2011We extend a previous result [Phys. Rev. Lett. 105, 090403 (2010)] on Casimir repulsion between a plate with a hole and a cylinder centered above it to geometries in which the central object can no longer be treated as a point dipole. We show through numerical ... More
Achieving a Strongly Temperature-Dependent Casimir EffectApr 15 2010We propose a method of achieving large temperature sensitivity in the Casimir force that involves measuring the stable separation between dielectric objects immersed in fluid. We study the Casimir force between slabs and spheres using realistic material ... More
Optical-approximation analysis of sidewall-spacing effects on the force between two squares with parallel sidewallsSep 05 2007Sep 05 2007Using the ray-optics approximation, we analyze the Casimir force in a two dimensional domain formed by two metallic blocks adjacent to parallel metallic sidewalls, which are separated from the blocks by a finite distance h. For h > 0, the ray-optics approach ... More
Nonmonotonic effects of parallel sidewalls on Casimir forces between cylindersNov 13 2007We analyze the Casimir force between two parallel infinite metal cylinders, with nearby metal plates (sidewalls), using complementary methods for mutual confirmation. The attractive force between cylinders is shown to have a nonmonotonic dependence on ... More
Computation and visualization of Casimir forces in arbitrary geometries: non-monotonic lateral forces and failure of proximity-force approximationsApr 15 2007Aug 09 2007We present a method of computing Casimir forces for arbitrary geometries, with any desired accuracy, that can directly exploit the efficiency of standard numerical-electromagnetism techniques. Using the simplest possible finite-difference implementation ... More
Efficient Computation of Casimir Interactions between Arbitrary 3D ObjectsApr 04 2009We introduce an efficient technique for computing Casimir energies and forces between objects of arbitrarily complex 3D geometries. In contrast to other recently developed methods, our technique easily handles non-spheroidal, non-axisymmetric objects ... More
Spherical cloaking using nonlinear transformations for improved segmentation into concentric isotropic coatingsMay 11 2009Two novel classes of spherical invisibility cloaks based on nonlinear transformation have been studied. The cloaking characteristics are presented by segmenting the nonlinear transformation based spherical cloak into concentric isotropic homogeneous coatings. ... More
Degenerate four-wave mixing in triply-resonant Kerr cavitiesNov 26 2010We demonstrate theoretical conditions for highly-efficient degenerate four-wave mixing in triply-resonant nonlinear (Kerr) cavities. We employ a general and accurate temporal coupled-mode analysis in which the interaction of light in arbitrary microcavities ... More
Casimir repulsion between metallic objects in vacuumMar 17 2010Aug 06 2010We give an example of a geometry in which two metallic objects in vacuum experience a repulsive Casimir force. The geometry consists of an elongated metal particle centered above a metal plate with a hole. We prove that this geometry has a repulsive regime ... More
Modeling near-field radiative heat transfer from sharp objects using a general 3d numerical scattering techniqueJul 11 2011Jul 18 2011We examine the non-equilibrium radiative heat transfer between a plate and finite cylinders and cones, making the first accurate theoretical predictions for the total heat transfer and the spatial heat flux profile for three-dimensional compact objects ... More
Casimir forces in the time domain II: ApplicationsJun 29 2009Oct 27 2009Our preceding paper introduced a method to compute Casimir forces in arbitrary geometries and for arbitrary materials that was based on a finite-difference time-domain (FDTD) scheme. In this manuscript, we focus on the efficient implementation of our ... More
Computation and visualization of photonic quasicrystal spectra via Blochs theoremNov 13 2007Mar 07 2008Previous methods for determining photonic quasicrystal (PQC) spectra have relied on the use of large supercells to compute the eigenfrequencies and/or local density of states (LDOS). In this manuscript, we present a method by which the energy spectrum ... More
Virtual photons in imaginary time: Computing exact Casimir forces via standard numerical-electromagnetism techniquesMay 24 2007Oct 17 2007We describe a numerical method to compute Casimir forces in arbitrary geometries, for arbitrary dielectric and metallic materials, with arbitrary accuracy (given sufficient computational resources). Our approach, based on well-established integration ... More
All-optical three-dimensional electron pulse compressionSep 23 2014Jan 28 2015We propose an all-optical, three-dimensional electron pulse compression scheme in which Hermite-Gaussian optical modes are used to fashion a three-dimensional optical trap in the electron pulse's rest frame. We show that the correct choices of optical ... More
A diameter--bandwidth product limitation of isolated-object cloakingMar 09 2012We show that cloaking of isolated objects is subject to a diameter-bandwidth product limitation: as the size of the object increases, the bandwidth of good (small cross-section) cloaking decreases inversely with the diameter, as a consequence of causality ... More
Cavity-enhanced second harmonic generation via nonlinear-overlap optimizationMay 12 2015May 18 2015We describe an approach based on topology optimization that enables automatic discovery of wavelength-scale photonic structures for achieving high-efficiency second-harmonic generation (SHG). A key distinction from previous formulation and designs that ... More
Classical and fluctuation-induced electromagnetic interactions in micronscale systems: designer bonding, antibonding, and Casimir forcesSep 11 2014Whether intentionally introduced to exert control over particles and macroscopic objects, such as for trapping or cooling, or whether arising from the quantum and thermal fluctuations of charges in otherwise neutral bodies, leading to unwanted stiction ... More
A novel boundary element method using surface conductive absorbers for full-wave analysis of 3-D nanophotonicsApr 28 2010Fast surface integral equation (SIE) solvers seem to be ideal approaches for simulating 3-D nanophotonic devices, as these devices generate fields both in an interior channel and in the infinite exterior domain. However, many devices of interest, such ... More
Casimir micro-sphere diclusters and three-body effects in fluidsDec 03 2010Apr 13 2011Our previous article [Phys. Rev. Lett. 104, 060401 (2010)] predicted that Casimir forces induced by the material-dispersion properties of certain dielectrics can give rise to stable configurations of objects. This phenomenon was illustrated via a dicluster ... More
Sufficient conditions for two-dimensional localization by arbitrarily weak defects in periodic potentials with band gapsFeb 24 2010Apr 28 2010We prove, via an elementary variational method, 1d and 2d localization within the band gaps of a periodic Schrodinger operator for any mostly negative or mostly positive defect potential, V, whose depth is not too great compared to the size of the gap. ... More
Ingredients of a Casimir analog computerMar 03 2009Mar 09 2009We present the basic ingredients of a technique to compute quantum Casimir forces at micrometer scales using antenna measurements at tabletop, e.g. centimeter, scales, forming a type of analog computer for the Casimir force. This technique relies on a ... More
Nonlinear harmonic generation and devices in doubly-resonant Kerr cavitiesAug 22 2008We describea theoretical analysis of the nonlinear dynamics of third-harmonic generation ($\omega\to3\omega$) via Kerr ($\chithree$) nonlinearities in a resonant cavity with resonances at both $\omega$ and $3\omega$. Such a doubly resonant cavity greatly ... More
Optimization of sharp and viewing-angle-independent structural colorOct 31 2014Jan 31 2015Structural coloration produces some of the most brilliant colors in nature and has many applications. However, the two competing properties of narrow bandwidth and broad viewing angle have not been achieved simultaneously in previous studies. Here, we ... More
Robust topology optimization of three-dimensional photonic-crystal band-gap structuresMay 17 2014May 20 2014We perform full 3D topology optimization (in which "every voxel" of the unit cell is a degree of freedom) of photonic-crystal structures in order to find optimal omnidirectional band gaps for various symmetry groups, including fcc (including diamond), ... More
Power--bandwidth limitations of an optical resonanceOct 23 2015We present shape-independent upper limits to the power--bandwidth product for a single resonance in an optical scatterer, with the bound depending only on the material susceptibility. We show that quasistatic metallic scatterers can nearly reach the limits, ... More
Three-dimensional topological photonic crystal with a single surface Dirac coneJul 01 2015A single Dirac cone on the surface is the hallmark of three-dimensional (3D) topological insulators, where the double degeneracy at the Dirac point is protected by time-reversal symmetry and the spin-splitting away from the point is provided by the spin-orbital ... More
Fluctuating volume-current formulation of electromagnetic fluctuations in inhomogeneous media: incandecence and luminescence in arbitrary geometriesMay 19 2015We describe a fluctuating volume--current formulation of electromagnetic fluctuations that extends our recent work on heat exchange and Casimir interactions between arbitrarily shaped homogeneous bodies [Phys. Rev. B. 88, 054305] to situations involving ... More
Maximal Spontaneous Photon Emission and Energy Loss from Free ElectronsJan 19 2019Free electron radiation such as Cerenkov, Smith--Purcell, and transition radiation can be greatly affected by structured optical environments, as has been demonstrated in a variety of polaritonic, photonic-crystal, and metamaterial systems. However, the ... More
Frequency-selective near-field enhancement of radiative heat transfer via photonic-crystal slabs: a general computational approach for arbitrary geometries and materialsMay 03 2011Aug 26 2011We demonstrate the possibility of achieving enhanced frequency-selective near-field radiative heat transfer between patterned (photonic crystal) slabs at designable frequencies and separations, exploiting a general numerical approach for computing heat ... More
General Theory of Spontaneous Emission Near Exceptional PointsApr 21 2016Sep 19 2016We present a general theory of spontaneous emission at exceptional points (EPs)---exotic degeneracies in non-Hermitian systems. Our theory extends beyond spontaneous emission to any light--matter interaction described by the local density of states (e.g., ... More
Interaction-induced mode switching in steady-state microlasersApr 29 2015Jan 22 2016We demonstrate that due to strong modal interactions through cross-gain saturation, the onset of a new lasing mode can switch off an existing mode via a negative power slope. In this process of interaction-induced mode switching (IMS) the two involved ... More
Structural anisotropy and orientation-induced Casimir repulsion in fluidsSep 23 2010May 12 2011In this work we theoretically consider the Casimir force between two periodic arrays of nanowires (both in vacuum, and on a substrate separated by a fluid) at separations comparable to the period. Specifically, we compute the dependence of the exact Casimir ... More
Stable suspension and dispersion-induced transitions from repulsive Casimir forces between fluid-separated eccentric cylindersJul 25 2008Nov 08 2008Using an exact numerical method for finite nonplanar objects, we demonstrate a stable mechanical suspension of a silica cylinder within a metallic cylinder separated by ethanol, via a repulsive Casimir force between the silica and the metal. We investigate ... More
Efficient Terahertz Generation in Triply Resonant Nonlinear Photonic Crystal MicrocavitiesAug 04 2009We propose a scheme for efficient cavity-enhanced nonlinear THz generation via difference-frequency generation (DFG) processes using a triply resonant system based on photonic crystal cavities. We show that high nonlinear overlap can be achieved by coupling ... More
Anomalous near-field heat transfer between a cylinder and a perforated surfaceJul 14 2012Jul 18 2012We predict that the radiative heat-transfer rate between a cylinder and a perforated surface depends non-monotonically on their separation. This anomalous behavior, which arises due to near-field effects, is explained using a heuristic model based on ... More
Geometry-induced Casimir suspension of oblate bodies in fluidsOct 16 2013We predict that a low-permittivity oblate body (disk-shaped object) above a thin metal substrate (plate with a hole) immersed in a fluidof intermediate permittivity will experience a meta-stable equilibrium (restoring force) near the center of the hole. ... More
Bonding, antibonding and tunable optical forces in asymmetric membranesDec 05 2010Jan 16 2011We demonstrate that tunable attractive (bonding) and repulsive (anti-bonding) forces can arise in highly asymmetric structures coupled to external radiation, a consequence of the bonding/anti-bonding level repulsion of guided-wave resonances that was ... More
Evanescent-Wave Bonding Between Optical WaveguidesSep 09 2005Forces arising from overlap between the guided waves of parallel, microphotonic waveguides are calculated. Both attractive and repulsive forces, determined by the choice of relative input phase, are found. Using realistic parameters for a silicon-on-insulator ... More
Perfect Single-Sided Radiation and Absorption without MirrorsJul 16 2016Sep 22 2016Highly directional radiation from photonic structures is important for many applications, including high power photonic crystal surface emitting lasers, grating couplers, and light detection and ranging devices. However, previous dielectric, few-layer ... More
General Theory of Spontaneous Emission Near Exceptional PointsApr 21 2016May 18 2017We present a general theory of spontaneous emission at exceptional points (EPs)---exotic degeneracies in non-Hermitian systems. Our theory extends beyond spontaneous emission to any light--matter interaction described by the local density of states (e.g., ... More
Measures on transitions for cosmology from eternal inflationDec 19 2006May 04 2007We argue that in the context of eternal inflation in the landscape, making predictions for cosmological -- and possibly particle physics -- observables requires a measure on the possible cosmological histories as opposed to one on the vacua themselves. ... More
Designing evanescent optical interactions to control the expression of Casimir forces in optomechanical structuresJan 21 2011Apr 18 2011We propose an optomechanical structure consisting of a photonic-crystal (holey) membrane suspended above a layered silicon-on-insulator substrate in which resonant bonding/antibonding optical forces created by externally incident light from above enable ... More
Ab-initio multimode linewidth theory for arbitrary inhomogeneous laser cavitiesFeb 25 2015May 13 2015We present a multimode laser-linewidth theory for arbitrary cavity structures and geometries that contains nearly all previously known effects and also finds new nonlinear and multimode corrections, e.g. a bad-cavity correction to the Henry $\alpha$ factor ... More
Calculation of nonzero-temperature Casimir forces in the time domainNov 22 2010We show how to compute Casimir forces at nonzero temperatures with time-domain electromagnetic simulations, for example using a finite-difference time-domain (FDTD) method. Compared to our previous zero-temperature time-domain method, only a small modification ... More
Difference-frequency generation with quantum-limited efficiency in triply-resonant nonlinear cavitiesMar 23 2009We present a comprehensive study of second-order nonlinear difference frequency generation in triply resonant cavities using a theoretical framework based on coupled-mode theory. We show that optimal quantum-limited conversion efficiency can be achieved ... More
Symmetry, stability, and computation of degenerate lasing modesNov 05 2016We present a general method to obtain the stable lasing solutions for the steady-state ab-initio lasing theory (SALT) for the case of a degenerate symmetric laser in two dimensions (2d). We find that under most regimes (with one pathological exception), ... More
Symmetry, stability, and computation of degenerate lasing modesNov 05 2016Feb 25 2017We present a general method to obtain the stable lasing solutions for the steady-state ab-initio lasing theory (SALT) for the case of a degenerate symmetric laser in two dimensions (2d). We find that under most regimes (with one pathological exception), ... More
Hurdles for Recent Measures in Eternal InflationNov 21 2006Mar 23 2007In recent literature on eternal inflation, a number of measures have been introduced which attempt to assign probabilities to different pocket universes by counting the number of each type of pocket according to a specific procedure. We give an overview ... More
Fundamental limits to optical response in absorptive systemsMar 12 2015Jan 06 2016At visible and infrared frequencies, metals show tantalizing promise for strong subwavelength resonances, but material loss typically dampens the response. We derive fundamental limits to the optical response of absorptive systems, bounding the largest ... More
Fundamental limits to nanoparticle extinctionNov 06 2013Nov 27 2013We show that there are shape-independent upper bounds to the extinction cross section per unit volume of randomly oriented nanoparticles, given only material permittivity. Underlying the limits are restrictive sum rules that constrain the distribution ... More
Optomechanical and Photothermal Interactions in Suspended Photonic Crystal MembranesOct 30 2012We present here an optomechanical system fabricated with novel stress management techniques that allow us to suspend an ultrathin defect-free silicon photonic-crystal membrane above a Silicon-on-Insulator (SOI) substrate with a gap that is tunable to ... More
Fourteen New Companions from the Keck & Lick Radial Velocity Survey Including Five Brown Dwarf CandidatesApr 25 2007We present radial velocities for 14 stars on the California & Carnegie Planet Search target list that reveal new companions. One star, HD 167665, was fit with a definitive Keplerian orbit leading to a minimum mass for the companion of 50.3 Mjup at a separation ... More
MIMIC-CXR: A large publicly available database of labeled chest radiographsJan 21 2019Jan 23 2019Chest radiography is an extremely powerful imaging modality, allowing for a detailed inspection of a patient's thorax, but requiring specialized training for proper interpretation. With the advent of high performance general purpose computer vision algorithms, ... More
A New Planet Around an M Dwarf: Revealing a Correlation Between Exoplanets and Stellar MassJul 16 2007We report precise Doppler measurements of GJ317 (M3.5V) that reveal the presence of a planet with a minimum mass Msini = 1.2 Mjup in an eccentric, 692.9 day orbit. GJ317 is only the third M dwarf with a Doppler-detected Jovian planet. The residuals to ... More
Spin-Orbit Alignment for the Eccentric Exoplanet HD 147506bJul 03 2007The short-period exoplanet HD 147506b (also known as HAT-P-2b) has an eccentric orbit, raising the possibility that it migrated through planet-planet scattering or Kozai oscillations accompanied by tidal dissipation. Either of these scenarios could have ... More
Qubit Models of Black Hole EvaporationSep 13 2011Aug 24 2012Recently, several simple quantum mechanical toy models of black hole evaporation have appeared in the literature attempting to illuminate the black hole information paradox. We present a general class of models that is large enough to describe both unitary ... More
A Direct Connection Between the Bergman and Szegő KernelsApr 26 2012We use Stokes's theorem to establish an explicit and concrete connection between the Bergman and Szeg\H{o} projections on the disc, the ball, and on strongly pseudoconvex domains.
Some New Thoughts on Maximal Functions and Poisson IntegralsOct 06 2010We study Wiener-type covering lemmas, Hardy-Littlewood-type maximal functions, and convergence theorems on metric spacs. Later we specialize down to a result for the Poisson integral. We show that, in a suitably general setting, these three phenomena ... More