Optics
- [1] arXiv:2405.08833 [pdf, ps, other]
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Title: GHz-rate optical phase shift in light matter interaction-engineered, silicon-ferroelectric nematic liquid crystalsIman Taghavi, Omid Esmaeeli, Sheri Jahan Chowdhury, Matthew Mitchell, Donald Witt, Cory Pecinovsky, Jason Sickler, Nicolas A.F. Jaeger, Sudip Shekhar, Lukas ChrostowskiComments: 21 pages, 5 figuresSubjects: Optics (physics.optics); Applied Physics (physics.app-ph)
Organic electro-optic (OEO) materials have demonstrated promising performance in developing electro-optic phase shifters (EOPS) and modulators compared to their inorganic counterparts. Integration with other devices in a silicon photonic (SiP) process, simple nanofabrication, and temperature/aging robustness remain to be developed for this class of hybrid material platforms. In particular, electro-optic (EO) polymers need an electro-thermal poling method, which has limited their potential and utilization in large-scale SiP. Devices made of paraelectric nematic liquid crystals (PN-LC), another primary type of OEO material, feature a very efficient but slow phase shift mechanism. We present a general-purpose EOPS that applies to various modulator embodiments to address these concerns. Based on that, we report a GHz-fast phase shift in a newly discovered family of OEO, namely ferroelectric nematic liquid crystals (FN-LC), which finally enables liquid crystals to have significant second-order nonlinear optical coefficients and associated Pockels effect. The new material avoids poling issues associated with EO polymers and can pave the way for hybrid silicon-OEO systems with CMOS-foundry compatibility. Furthermore, we propose a finger-loaded, non-slotted waveguide that enhances light-matter interaction, allowing us to achieve DC and AC modulation efficiencies of $\approx$ 0.25 this http URL and 25.7 this http URL, respectively, an on-chip insertion loss of $\approx$ 4 dB, and an EO bandwidth of f$_{-6dB}$ >4.18 GHz. The remaining figures of merit for our poling-free EOPS are equivalent to EO polymer-enabled devices with fewer manufacturing difficulties. We demonstrate an electrically and photonically packaged chip that contains >100 silicon-FN-LC modulators to evaluate the large-scale integration of our poling-free phase shifters and modulators.
- [2] arXiv:2405.08835 [pdf, ps, other]
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Title: There Are Two Distinct Photon Gases Present Inside Every Solar CellComments: 13 Pages, 3 Figures embedded in the pdfSubjects: Optics (physics.optics); Other Condensed Matter (cond-mat.other)
It has gradually been recognized that incoming sunlight can be trapped within a high refractive index semiconductor, n~3.5, owing to the narrow 16degree escape cone. The solar light inside a semiconductor is 4n^2 times brighter than incident sunlight. This is called light trapping and has increased the theoretical and practical efficiency of solar panels. But there is a second photon gas of equal importance that has been overlooked. Inside every forward-biased solar cell there is a gas of infrared luminescence photons, also trapped by total internal reflection. We introduce the idea of super-equilibrium, when the luminescence photon gas freely exchanges energy with the two quasi-Fermi levels.
Nonetheless, the loss of a single photon from either gas is equivalent to the loss of a precious minority carrier. Therefore optical modeling & design becomes equally important as electron-hole modeling in high efficiency solar cells. It becomes possible to approach the idealistic Shockley-Queisser limit, by proper material selection and design of the solar cell optics. - [3] arXiv:2405.08836 [pdf, ps, other]
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Title: Piezoelectric actuation for integrated photonicsSubjects: Optics (physics.optics); Applied Physics (physics.app-ph)
Recent decades have seen significant advancements in integrated photonics, driven by improvements in nanofabrication technology. This field has developed from integrated semiconductor lasers and low-loss waveguides to optical modulators, enabling the creation of sophisticated optical systems on a chip scale capable of performing complex functions like optical sensing, signal processing, and metrology. The tight confinement of optical modes in photonic waveguides further enhances the optical nonlinearity, leading to a variety of nonlinear optical phenomena such as optical frequency combs, second-harmonic generation, and supercontinuum generation. Active tuning of photonic circuits is crucial not only for offsetting variations caused by fabrication in large-scale integration, but also serves as a fundamental component in programmable photonic circuits. Piezoelectric actuation in photonic devices offers a low-power, high-speed solution and is essential in the design of future photonic circuits due to its compatibility with materials like Si and Si3N4, which do not exhibit electro-optic effects. Here, we provide a detailed review of the latest developments in piezoelectric tuning and modulation, by examining various piezoelectric materials, actuator designs tailored to specific applications, and the capabilities and limitations of current technologies. Additionally, we explore the extensive applications enabled by piezoelectric actuators, including tunable lasers, frequency combs, quantum transducers, and optical isolators. These innovative ways of managing photon propagation and frequency on-chip are expected to be highly sought after in the future advancements of advanced photonic chips for both classical and quantum optical information processing and computing.
- [4] arXiv:2405.08840 [pdf, ps, other]
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Title: Femtosecond laser writing of depressed cladding waveguides in sapphireSarah Winkler, Joachim R. Krenn, Jakob Wahl, Alexander Zesar, Yves Colombe, Klemens Schüppert, Clemens Rössler, Christian Sommer, Philipp Hurdax, Philip Lichtenegger, Bernhard LamprechtSubjects: Optics (physics.optics); Quantum Physics (quant-ph)
A promising solution for scalable integrated optics of trapped-ion quantum processors are curved waveguides guiding visible light within sapphire bulk material. To the best of our knowledge, no curved waveguides were investigated in sapphire so far and no waveguides for visible light in undoped planar sapphire substrates were reported. Here, we demonstrate femtosecond laser writing of depressed cladding waveguides in sapphire. Laser parameters such as pulse energy, pulse duration, and repetition rate, as well as waveguide geometry parameters were optimized to guide 728 nm light. This resulted in single-mode waveguides with a propagation loss of 1.9 (3) dB/cm. The investigation of curved waveguides showed a sharp increase in total loss for curvature radii below 15 mm. Our results demonstrate the potential of femtosecond laser writing as a powerful technique for creating integrated optical waveguides in the volume of sapphire substrates. Such waveguides could be a building block for integrated optics in trapped ion quantum processors.
- [5] arXiv:2405.08847 [pdf, ps, other]
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Title: Double symmetry and phase-controlled continuous transformation between skyrmion and meron topologySubjects: Optics (physics.optics)
Topological quasiparticles, including skyrmions and merons, are topological textures with sophisticated vectorial structures that can be used for optical information storage, precision metrology, position sensing, etc. Here, we build a simple model to generate the isolated Néel-type field-skyrmion and derive the analytical solution of it. By employing a series of well-designed double-symmetry apertures and controlling the initial phase of light, we realized the continuous transformation between the isolated skyrmion, the meron lattice, and the skyrmion lattice. We show that the field symmetry determines the possible forms of the topological texture, and the initial phase switches the presentation form of it. These results enrich the methods for generating and transforming topological textures, provide new insights into the symmetry of the electromagnetic field, and open up new opportunities for precision measurement and topological photonics.
- [6] arXiv:2405.08850 [pdf, ps, html, other]
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Title: Parametrically encircled higher-order exceptional points in anti-parity-time symmetric optical microcavitiesComments: 8 pages, 3 figuresSubjects: Optics (physics.optics)
The fascinating realm of non-Hermitian physics with the interplay of parity (P) and time-reversal (T) symmetry has been witnessing immense attention in exploring unconventional physics at Exceptional Point (EP) singularities. Particularly, the physics of PT-symmetry, anti-PT (APT)-symmetry, and the emergence of EPs have ignited fervor in photonics. Beyond the conventional relation between EP and PT-symmetric phase transitions, this study delves into hosting higher-order EPs in a specially designed APT-symmetric Fabry-Pérot-type microcavity. We unveil the captivating physics of the parametric encirclement schemes to explore the branch-point behaviors of EPs up to order three in terms of successive state-flipping, while optimizing the designed cavity under APT-symmetric constraints. The insights from our findings are poised to boost research in optical metamaterials, meeting the demands of APT-symmetry and paving the way for a novel class of photonic devices.
- [7] arXiv:2405.08851 [pdf, ps, other]
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Title: Enhanced Terahertz Spectroscopy of a Monolayer Transition Metal DichalcogenideXin Jin, Vincenzo Aglieri, Young-Gyun Jeong, Atiye Pezeshki, Lilian Skokan, Mostafa Shagar, Yuechen Jia, Pablo Bianucci, Andreas Ruediger, Emanuele Orgiu, Andrea Toma, Luca RazzariSubjects: Optics (physics.optics)
Two-dimensional materials, including transition metal dichalcogenides, are attractive for a variety of applications in electronics as well as photonics and have recently been envisioned as an appealing platform for phonon polaritonics. However, their direct characterization in the terahertz spectral region, of interest for retrieving, e.g., their phonon response, represents a major challenge, due to the limited sensitivity of typical terahertz spectroscopic tools and the weak interaction of such long-wavelength radiation with sub-nanometer systems. In this work, by exploiting an ad-hoc engineered metallic surface enabling a ten-thousand-fold local absorption boost, we perform enhanced terahertz spectroscopy of a monolayer transition metal dichalcogenide (tungsten diselenide) and extract its dipole-active phonon resonance features. In addition, we use these data to obtain the monolayer effective permittivity around its phonon resonance. Via the direct terahertz characterization of the phonon response of such two-dimensional systems, this method opens the path to the rational design of phonon polariton devices exploiting monolayer transition metal dichalcogenides.
- [8] arXiv:2405.08854 [pdf, ps, other]
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Title: Eliminating nearfield coupling in dense high quality factor phase gradient metasurfacesComments: 25 pages,11 figuresSubjects: Optics (physics.optics)
High Q phase gradient metasurfaces are becoming promising elements for revolutionizing light manipulation but near-field coupling typically forces a trade-off between quality factor and resolution. Here, we show a strategy for not just reducing but eliminating coupling-based nonlocal effects in wave shaping metasurfaces composed of meta-pixels with arbitrarily high Q arranged with sub-diffraction spatial resolution. By working at a zero-coupling regime introduced by the interference between enhanced longitudinal and transverse electric fields, the tradeoff between Q and resolution no longer exists. Exploiting for wave shaping the ability to fully suppress coupling between high Q meta-atoms, we numerically show structurally uniform devices that produce beam-splitting to angles of $\pm53^o$ and beam-steering to an angle of $33^o$ with diffraction efficiencies over 90% via refractive index bias of just $2\times10^{-6}$ and $7\times10^{-6}$, respectively. These are made possible by the meta-structure supporting local dipole resonances with Qs of 2.8 million and 0.87 million respectively, arranged with a dense pixel pitch of ${\lambda}/1.6$. Extending the approach to structures with ${\lambda}/2.2$ resolution we also unlock full-field beam steering via index biasing of just $1\times10^{-4}$. The signature of a zero-coupling regime is discovered in the form of a sign flip in the angular dispersion with resonant wavelength in experiment which validates our scheme. Aside from triangulating a perfect decoupling configuration, one of our fabricated nanofin-isolated metasurfaces with Q-factor >870 has a resonant wavelength that stays within the half linewidth for incident angles of $-20^o$ to $20^o$. Our platform provides a route for densely arrayed high Q metasurfaces with independently addressable constituent meta-atoms, paving the way for highly efficient nonlinear and dynamic wavefront shaping.
- [9] arXiv:2405.08903 [pdf, ps, html, other]
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Title: Intuitive understanding of extinction of small particles in absorbing and active host media within the MLWASubjects: Optics (physics.optics)
In an absorbing or an active host medium characterized by a complex refractive index $n_2=n_2'+{\rm i}n_2''$, our previously developed modified dipole long-wave approximation (MLWA) is shown to essentially overly with the exact Mie theory results for spherical nanoparticle with radius $a\lesssim 25$ nm ($a\lesssim 20$ nm) in the case of Ag and Au (Al and Mg) nanoparticles. The agreement for Au and Ag (Al and Mg) nanoparticles, slightly better in the case of Au than Ag, continues to be acceptable up to $a\sim 50$ nm ($a\sim 40$ nm), and can be used, at least qualitatively, up to $a\sim 70$~nm ($a\sim 50$ nm) correspondingly. A first order analytic perturbation theory (PT) in a normalized extinction coefficient, $\bar\kappa=n_2''/n_2'$, around a nonabsorbing host is developed within the dipole MLWA and its properties are investigated. It is shown that, in a suitable parameter range, the PT can reliably capture the effect of host absorption or gain on the extinction efficiency of various plasmonic nanoparticles.
- [10] arXiv:2405.08972 [pdf, ps, other]
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Title: Detecting Hollow Electron Beams via Smith-Purcell Radiation from a MetasurfaceComments: 7 pages, 5 figuresSubjects: Optics (physics.optics)
Hollow electron beams are today highly desirable for many applications, but are still challenging in view of their detection. In this Letter, we focus on the unique character of the electromagnetic radiation that relativistic hollow electron beams can produce when traveling above a metasurface. We investigate theoretically the specific features of the radiation in a coherent mode, which provides the highest intensity, and show that the radiation from a hollow beam can be considerably more intense than that from a conventional solid beam. This solves the problem of distinguishing between hollow and solid beams. Moreover, we consider the two-layer internal structure of a hollow beam and reveal that the radiation characteristics are sensitive to the width and population of each layer. This allows detecting the internal structure of hollow beams. Interestingly, we found that the factor describing the annular beam form is a separated multiplier in a conventional form factor, independent of the properties of periodic structure. Thus, we can conclude that our results will stay correct for different profiles of periodic structures and metasurfaces made of metaatoms of different topologies and forms. The results pave the way towards a variety of newly emerging applications based on hollow electron beams, very diverse in topics, such as manipulation of objects at the nano-level, studies of chiral matter, plasma acceleration in donut wakefields and even applications in huge facilities such as LHC for controlling proton beam halos etc.
- [11] arXiv:2405.08987 [pdf, ps, html, other]
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Title: A practical guide to light-sheet microscopy for nanoscale imaging: Looking beyond the cellComments: 65 pages, 16 figures, submitted to Journal of Applied PhysicsSubjects: Optics (physics.optics); Instrumentation and Detectors (physics.ins-det)
We present a comprehensive guide to light-sheet microscopy (LSM) to assist scientists in navigating the practical implementation of this microscopy technique. Emphasizing the applicability of LSM to image both static microscale and nanoscale features, as well as diffusion dynamics, we present the fundamental concepts of microscopy, progressing through beam profile considerations, to image reconstruction. We outline key practical decisions in constructing a home-built system and provide insight into the alignment and calibration processes. We briefly discuss the conditions necessary for constructing a continuous 3D image and introduce our home-built code for data analysis. By providing this guide, we aim to alleviate the challenges associated with designing and constructing LSM systems and offer scientists new to LSM a valuable resource in navigating this complex field.
- [12] arXiv:2405.09020 [pdf, ps, other]
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Title: Scalable single-microring hybrid III-V/Si lasers for emerging narrow-linewidth applicationsJiawei Wang, Xiang Li, Xin Guo, Ter-Hoe Loh, Luigi Ranno, Chongyang Liu, Rusli, Hong Wang, Jia Xu Brian SiaComments: 11 pages, 8 figuresSubjects: Optics (physics.optics); Applied Physics (physics.app-ph)
Silicon photonics, compatible with large-scale silicon manufacturing, is a disruptive photonic platform that has indicated significant implications in industry and research areas (e.g., quantum, neuromorphic computing, LiDAR). Cutting-edge applications such as high-capacity coherent optical communication and heterodyne LiDAR have escalated the demand for integrated narrow-linewidth laser sources. To that effect, this work seeks to address this requirement through the development of a high-performance hybrid III-V/silicon laser. The developed integrated laser, utilizes a single microring resonator (MRR), demonstrating single-mode operation with a side mode suppression ratio (SMSR) exceeding 40 dB, with laser output power as high as 16.4 mW. Moving away from current hybrid/heterogeneous laser architectures that necessitate multiple complex control, the developed laser architecture requires only two control parameters. Importantly, this serves to streamline industrial adoption by reducing the complexity involved in characterizing these lasers, at-scale. Through the succinct structure and control framework, a narrow laser linewidth of 2.79 kHz and low relative intensity noise (RIN) of -135 dB/Hz are achieved. Furthermore, optical data transmission at 12.5 Gb/s is demonstrated where a signal-to-noise ratio (SNR) of 10 dB is measured.
- [13] arXiv:2405.09047 [pdf, ps, other]
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Title: Topological Laser in Anomalous Quadrupole Topological PhasesSubjects: Optics (physics.optics)
Topological photonics shows considerable promise in revolutionizing photonic devices through the use of topological phases, leading to innovations like topological lasers that enhance light control. One of recent breakthroughs is reducing the size of these systems by utilizing lower-dimensional boundary states, notably via higher-order topological phases. This paper presents the first experimental demonstration of topological laser in anomalous quadrupole topological phase, an instance of higher-order phases. To facilitate this, a topological nanocavity with quality factor near 6,000 is engineered through a twisting operation. The topological nature of our system is validated by calculation of nested Wannier center and the emergency condition of corner states. Our experimental observations reveal the manifestation of corner states and the achievement of single-mode pulsed laser, driven by optical gain from multiple quantum wells at telecommunication wavelengths and at a temperature of 4 K. A lasing threshold of 23 uW and a cold quality factor of 1,500 are deduce through rate equation. Our work gives a new potential in the application of topological principles to advance nanophotonic technologies.
- [14] arXiv:2405.09048 [pdf, ps, other]
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Title: Beam Shaping Based on Axisymmetric Aspheric MirrorsComments: 7 pages, 9 figuresSubjects: Optics (physics.optics)
Flat-top beam, known for its ability to generate a consistently even irradiation area, holds vast utility in many fields of scientific and industrial applications. In this paper, a reflective laser beam shaping method based on two axisymmetric aspheric mirrors (AAMs), a polarizing beam splitter (PBS) and two quarter wave plates (QWPs) is proposed to transform Gaussian beam into flat-top beam. Compared to alternative beam shaping methods, the method using AAMs demonstrates distinct advantages on notably high energy efficiency and unique capability to generate parallel beams. Thanks to its relative simplicities of design, manufacture and tunability, AAMs-shaping further enhances its appeal in applied research scenarios.
- [15] arXiv:2405.09065 [pdf, ps, html, other]
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Title: Efficient optical beam displacement measurements using high-order Hermite-Gaussian modesSubjects: Optics (physics.optics); Quantum Physics (quant-ph)
We develop a novel interferometric technique to measure small angular and lateral displacements of an optical beam. The technique relies on the metrological performance of the Hermite-Gaussian $HG_{m,0}$ spatial modes. We report an improvement factor of $41$ in the signal-to-noise ratio, as compared to the Gaussian mode, using modes as high as $m=20$. This considerably enhances the sensitivity of such measurements and attests its efficiency.
- [16] arXiv:2405.09160 [pdf, ps, html, other]
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Title: Temporal Talbot Effect: From a Quasi-Linear Talbot Carpet to Soliton Crystals and Talbot SolitonsSubjects: Optics (physics.optics)
The temporal Talbot effect refers to the periodic self-imaging of pulse trains in optical fibers. The connection between the linear and nonlinear temporal Talbot effect is still not fully understood. To address this challenge, we use Soliton Radiation Beat Analysis and numerically investigate the evolution of a phase-modulated continuous-wave laser input in a passive single-mode fiber. We identify three input-power-dependent regimes and their Talbot carpets: the quasi-linear regime for low input powers, the intermediate one, and separated Talbot solitons for higher powers. We show that the intermediate regime hosts soliton crystals rather than rogue waves, as reported in the literature. The Talbot-solitons beating can be used for pulse repetition-rate multiplication in the nonlinear regime. We also show two types of solitons involved: some encoded in the whole frequency comb and the individual solitons carried only by particular comb lines.
- [17] arXiv:2405.09313 [pdf, ps, html, other]
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Title: Vortex-comb spectroscopyComments: 8 pages, 4 figuresSubjects: Optics (physics.optics)
We propose a new Fourier-transform spectroscopy technique based on the rotational Doppler effect. The technique offers an application for optical vortex frequency combs, where each frequency component carries a unique amount of orbital angular momentum (OAM). Here, we emulate a vortex comb using a tunable single frequency laser and a collection of spiral phase plates, generating up to eleven distinct OAM modes. Unlike in traditional Fourier-transform spectroscopy based on the Michelson interferometer (linear Doppler effect), the spectral resolution of vortex-comb spectroscopy is not limited by the mechanical scan distance of the instrument but only by the measurement time. Although the spectrometer requires just one free-running frequency comb, the down-conversion scheme resembles dual-comb spectroscopy, leading to fast mode-resolved measurements.
- [18] arXiv:2405.09340 [pdf, ps, other]
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Title: Laser Printing of Silver and Silver OxideSubjects: Optics (physics.optics); Materials Science (cond-mat.mtrl-sci)
We show that direct laser writing (DLW) in aqueous silver nitrate with a 1030 nm femtosecond (fs) laser results in deposition of a mixture of silver oxide and silver, in contrast to the pure silver deposition previously reported with 780 nm fs DLW. However, adding photoinitiator prevents silver oxide formation in a concentration-dependent manner. As a result, the resistivity of the material can also be controlled by photoinitiator concentration with resistivity being reduced from approximately 9e-3 $\Omega m$ to 3e-7 $\Omega m$. Silver oxide peaks dominate the X-ray diffraction spectra when no photoinitiator is present, while the peaks disappear with photoinitiator concentrations above 0.05wt%. While femtosecond pulses are needed to initiate deposition, a continues-wave laser when well overlapped with the previously written material and supplying enough average power can lead to further printing, suggesting thermal deposition can also occur where the photoinitiator molecule also acts as a general reducing agent that prevents oxide formation. We also compare the surface quality of printed lines for different photoinitiator concentrations and laser printing conditions. A THz polarizer and metamaterial are printed as a demonstration of silver oxide printing.
- [19] arXiv:2405.09456 [pdf, ps, html, other]
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Title: Photonic Landau levels in a high-dimensional frequency-degenerate cavitySubjects: Optics (physics.optics)
Topological orders emerge in both microscopic quantum dynamics and macroscopic materials as a fundamental principle to characterize intricate properties in nature with vital significance, for instance, the Landau levels of electron systems in magnetic field. Whilst, recent advances of synthetic photonic systems enable generalized concepts of Landau levels across fermionic and bosonic systems, extending the modern physical frontier. However, the controls of Landau levels of photons were only confined in complex artificial metamaterials or multifolded cavities. Here, we exploit advanced structured light laser technology and propose the theory of high-dimensional frequency-degeneracy, which enables photonic Landau level control in a linear open laser cavity with simple displacement tuning of intracavity elements. This work not only create novel structured light with new topological effects but also provides broad prospects for Bose-analogue quantum Hall effects and topological physics.
New submissions for Thursday, 16 May 2024 (showing 19 of 19 entries )
- [20] arXiv:2405.08845 (cross-list from physics.app-ph) [pdf, ps, html, other]
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Title: Nanosecond Electron Holography by Interference GatingJournal-ref: In Ultramicroscopy (Vol. 206, p. 112824). Elsevier BV (2019)Subjects: Applied Physics (physics.app-ph); Optics (physics.optics)
The interference gating is a novel method for robust time-resolved electron holographic measurements by directly switching the interference. Here, a new arrangement is presented in which a biprism in the condenser aperture as a fast electric phase shifter is used to control the interference pattern. High-frequency stimulation of the electric phase shifter in the gigahertz range are performed and observed via electron holography, proving the feasibility of interference gating in the upper picosecond range. Despite the bandwidth limitation of 180~MHz of the current signal generator, a time resolution of 100 nanoseconds is achieved through forward correction of the control signal. With this time resolution, it is already possible to measure the transient response of the biasing holder system. Our method paves the way towards a closer look on fast dynamic processes with high temporal and spatial resolution.
- [21] arXiv:2405.09117 (cross-list from physics.atom-ph) [pdf, ps, html, other]
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Title: Complex-valued 3D atomic spectroscopy with Gaussian-assisted inline holographyComments: 20 pages, 7 figures;Subjects: Atomic Physics (physics.atom-ph); Optics (physics.optics); Quantum Physics (quant-ph)
When a laser-cooled atomic sample is optically excited, the envelope of coherent forward scattering can often be decomposed into a few complex Gaussian profiles. The convenience of Gaussian propagation helps addressing key challenges in digital holography. In this work, we theoretically develop and experimentally demonstrate a Gaussian-decomposition-assisted approach to inline holography, for single-shot, simultaneous measurements of absorption and phase shift of small atomic samples sparsely distributed in 3D. Experimentally, we image a sparse lattice of $^{87}$Rb samples on the D2 line, to resolve their axial positions with micrometer precision, and to retrieve their complex-valued spectroscopic images. With the phase-angle readouts that are highly insensitive to atom-number and interaction-strength uncertainties, we achieve hundred-kHz-level single-shot-resolution to the transition frequency with merely hundreds of atoms. We further demonstrate 3D sensing of local light shift with micrometer spatial resolution.
- [22] arXiv:2405.09246 (cross-list from cond-mat.mes-hall) [pdf, ps, html, other]
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Title: Unconventional magnetism mediated by spin-phonon-photon couplingJournal-ref: Nature Communications 15, 4000 (2024)Subjects: Mesoscale and Nanoscale Physics (cond-mat.mes-hall); Materials Science (cond-mat.mtrl-sci); Optics (physics.optics); Quantum Physics (quant-ph)
Magnetic order typically emerges due to the short-range exchange interaction between the constituent electronic spins. Recent discoveries have found a crucial role for spin-phonon coupling in various phenomena from optical ultrafast magnetization switching to dynamical control of the magnetic state. Here, we demonstrate theoretically the emergence of a biquadratic long-range interaction between spins mediated by their coupling to phonons hybridized with vacuum photons into polaritons. The resulting ordered state enabled by the exchange of virtual polaritons between spins is reminiscent of superconductivity mediated by the exchange of virtual phonons. The biquadratic nature of the spin-spin interaction promotes ordering without favoring ferro- or antiferromagnetism. It further makes the phase transition to magnetic order a first-order transition, unlike in conventional magnets. Consequently, a large magnetization develops abruptly on lowering the temperature which \aknew{could} enable magnetic memories admitting ultralow-power thermally-assisted writing while maintaining a high data stability. The role of photons in the phenomenon further enables an in-situ static control over the magnetism. These unique features make our predicted spin-spin interaction and magnetism highly unconventional paving the way for novel scientific and technological opportunities.
Cross submissions for Thursday, 16 May 2024 (showing 3 of 3 entries )
- [23] arXiv:2011.09229 (replaced) [pdf, ps, other]
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Title: Producing slow light in warm alkali vapor using electromagnetically induced transparencyComments: 15 pages, 10 figures (Supplementary Notes: 8 pages, 4 figures)Journal-ref: American Journal of Physics 91, 193-205 (2023)Subjects: Optics (physics.optics); Atomic Physics (physics.atom-ph); Quantum Physics (quant-ph)
We present undergraduate-friendly instructions on how to produce light pulses propagating through warm Rubidium vapor with speeds less than 400 m/s, i.e., nearly a million times slower than c. We elucidate the role played by electromagnetically induced transparency (EIT) in producing slow light pulses, and discuss how to achieve the required experimental conditions. The optical set up is presented, and details provided for preparation of pump, probe, and reference pulses of the required size, frequency, intensity, temporal width, and polarization purity. EIT-based slow light pulses provide the most widely studied architecture for creating quantum memories. Therefore, the basic concepts presented here are useful for physics and engineering majors who wish to get involved in the development of cutting-edge quantum technologies.
- [24] arXiv:2401.13506 (replaced) [pdf, ps, html, other]
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Title: Interferometric measurement of the deflection of light by light in airAdrien E. Kraych, Aurélie Max Mailliet, François Couchot, Xavier Sarazin, Elsa Baynard, Julien Demailly, Moana Pittman, Arache Djannati-Ataï, Sophie Kazamias, Scott Robertson, Marcel UrbanComments: 14 pages, 10 figures, submitted to Phys. Rev. ASubjects: Optics (physics.optics); High Energy Physics - Experiment (hep-ex); Quantum Physics (quant-ph)
The aim of the DeLLight (Deflection of Light by Light) experiment is to observe for the first time the optical nonlinearity in vacuum, as predicted by Quantum Electrodynamics, by measuring the refraction of a low-intensity focused laser pulse (probe) when crossing the effective vacuum index gradient induced by a high-intensity focused laser pulse (pump). The deflection signal is amplified by using a Sagnac interferometer. Here, we report the first measurement performed with the DeLLight pilot interferometer, of the deflection of light by light in air, with a low-intensity pump. We show that the deflection signal measured by the interferometer is amplified, and is in agreement with the expected signal induced by the optical Kerr effect in air. Moreover, we verify that the signal varies as expected as a function of the pump intensity, the temporal delay between the pump and the probe, and their relative polarisation. These results represent a proof of concept of the DeLLight experimental method based on interferometric amplification.
- [25] arXiv:2401.16171 (replaced) [pdf, ps, html, other]
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Title: Fiber-based high-speed fringe projection profilometrySubjects: Optics (physics.optics)
Phase shift profilometry has become a standard technique for recording the surface of an object using the projection of sinusoidal patterns. We present a method of projecting the patterns via a pair of single-mode optical fibers mounted within a needle. The system presented can capture sub-millimetre precision depth profiles at 60 frames per second. The key features of the system that enable the high-speed imaging are the creation of an automated calibration system and developments in the image unwrapping and reconstruction algorithms to produce high fidelity surface measurements. These methods produce a compact projection system capable of accurate and fast profilometry.
- [26] arXiv:2402.13947 (replaced) [pdf, ps, html, other]
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Title: Achiral nanostructures: perturbative harmonic generation and dichroism under vortex and vector beams illuminationComments: 57 pages, 5 figuresSubjects: Optics (physics.optics)
In this study, we investigate the nonlinear optical phenomena emerging from the interaction of vortex and vector beams with achiral nanoparticles or nanostructures. We reveal the conditions under which linear or nonlinear dichroism can be observed. Despite the achiral symmetry of the nanostructure, the interplay between the symmetries of the vortex beam, the nanostructure, and the crystalline lattice of the nanostructure material may result in circular dichroism in the nonlinear regime. We derive a formula that describes the conditions for the appearance of circular dichroism across a broad range of scenarios, taking into account all the symmetries. Building on these findings, we have determined the conditions for both linear and nonlinear dichroism when illuminated by vector beams. We believe that this work provides important insights that can enhance the design of chiral sensors and optical traps, making them more versatile and effective.
- [27] arXiv:2402.14330 (replaced) [pdf, ps, other]
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Title: Collisions of Light Bullets with Different Circular PolarizationsComments: 7 pages, 15 figures, in English, to appear as [JETP Lett. 119(8), 585 (2024)]Subjects: Optics (physics.optics); Pattern Formation and Solitons (nlin.PS)
Collisions of left- and right-polarized spatiotemporal optical solitons have been numerically simulated for a locally isotropic focusing Kerr medium with anomalous chromatic dispersion. The stable propagation of such ``light bullets'' in a moderate nonlinear regime is ensured by a transverse parabolic profile of the refraction index in a multimode waveguide. The transverse motion of centers of mass of wave packets in such systems occurs on classical trajectories of a harmonic oscillator, whereas the motion in the longitudinal direction is uniform. Therefore, collisions of two solitons can be not only head-on but also tangential. An inelastic collision of two solitons with opposite circular polarizations can result either in two binary light bullets combining the left and right polarization or in more complex bound systems.
DOI: https://doi.org/10.1134/S0021364024600691 - [28] arXiv:2403.01019 (replaced) [pdf, ps, html, other]
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Title: Two-photon absorption in silicon using real density matrix approachDavid Ziemkiewicz, David Knez, Evan P. Garcia, Sylwia Zielińska-Raczyńska, Gerard Czajkowski, Alessandro Salandrino, Sergey S. Kharintsev, Aleksei I. Noskov, Eric O. Potma, Dmitry A. FishmanSubjects: Optics (physics.optics)
Two-photon absorption in indirect gap semiconductors is an frequently encountered, but not well-understood phenomenon. To address this, the Real Density Matrix Approach is applied to describe two-photon absorption in silicon through the excitonic response to the interacting fields. This approach produces an analytical expression for the dispersion of the two-photon absorption coefficient for indirect-gap materials, and can be used to explain trends in reported experimental data for bulk silicon both old and new with minimal fitting.
- [29] arXiv:2404.05977 (replaced) [pdf, ps, html, other]
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Title: Passive Non-line-of-sight imaging of moving targets using Physical embedding and Event-based visionComments: 13 pages, 11 figuresSubjects: Optics (physics.optics)
Passive Non-line-of-sight (NLOS) imaging has shown promising applications in imaging occluded objects around corners. However, this inverse problem is highly ill-posed and results in poor reconstruction with traditional physical retrieval methods, particularly in moving target imaging. With the development of neural networks, data-driven methods have greatly improved accuracy, however, heavy reliance on data volume has put great pressure on data collection and dataset fabrication. We propose a physical embedded passive NLOS imaging prototype with event-based vision (PNPE), which induces an event camera for feature extraction of dynamic diffusion spot and leverages simulation dataset to pre-train the physical embedded model before fine-tuning with limited real-shot data. The proposed PNPE is verified by simulation and real-world experiments, and the comparisons of data paradigms also validate the superiority of event-based vision in passive NLOS imaging for moving targets.
- [30] arXiv:2404.12459 (replaced) [pdf, ps, html, other]
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Title: Recoil heating of a dielectric particle illuminated by a linearly polarized plane wave within the Rayleigh regimeSubjects: Optics (physics.optics); Quantum Physics (quant-ph)
We investigate the recoil heating phenomenon experienced by a dielectric spherical particle when it interacts with a linearly polarized plane wave within the Rayleigh regime. We derive the fluctuating force acted upon the particle arising from the fluctuations of the electromagnetic fields. Our derivations reveal that the spectral density of the fluctuating force along the propagation direction is $7\hbar \omega_0 P_{\mathrm{scat}}/5c^2$. Meanwhile, along the direction of the electric and magnetic fields, it is $\hbar \omega_0 P_{\mathrm{scat}}/5c^2$ and $2\hbar \omega_0 P_{\mathrm{scat}}/5c^2$, respectively. Here, $P_{\mathrm{scat}}$ denotes the power scattered by the particle, $\hbar\omega_0$ represents the energy of a photon, and $c$ is the speed of light. Recoil heating imposes fundamental limitations in levitated optomechanics, constraining the minimum temperatures achievable in cooling processes, the coherence time of the system, and the sensitivity of force measurements.
- [31] arXiv:2405.07706 (replaced) [pdf, ps, other]
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Title: Propagation-invariant strongly longitudinally polarized toroidal pulsesSubjects: Optics (physics.optics); Classical Physics (physics.class-ph)
Recent advancements in optical, terahertz, and microwave systems have unveiled non-transverse optical toroidal pulses characterized by skyrmionic topologies, fractal-like singularities, space-time nonseparability, and anapole-exciting ability. Despite this, the longitudinally polarized fields of canonical toroidal pulses notably lag behind their transverse counterparts in magnitude. Interestingly, although mushroom-cloud-like toroidal vortices with strong longitudinal fields are common in nature, they remain unexplored in the realm of electromagnetics. Here, we present strongly longitudinally polarized toroidal pulses (SLPTPs) which boast a longitudinal component amplitude exceeding that of the transverse component by over tenfold. This unique polarization property endows SLPTPs with robust propagation characteristics, showcasing nondiffracting behavior. The propagation-invariant strongly longitudinally polarized field holds promise for pioneering light-matter interactions, far-field superresolution microscopy, and high-capacity wireless communication utilizing three polarizations.
- [32] arXiv:2405.07878 (replaced) [pdf, ps, html, other]
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Title: Effective medium properties of stealthy hyperuniform photonic structures using multiscale physics-informed neural networksSubjects: Optics (physics.optics); Disordered Systems and Neural Networks (cond-mat.dis-nn); Applied Physics (physics.app-ph)
In this article, we employ multiscale physics-informed neural networks (MscalePINNs) for the inverse retrieval of the effective permittivity and homogenization of finite-size photonic media with stealthy hyperuniform (SHU) disordered geometries. Specifically, we show that MscalePINNs are capable of capturing the fast spatial variations of complex fields scattered by arrays of dielectric nanocylinders arranged according to isotropic SHU point patterns, thus enabling a systematic methodology to inverse retrieve their effective dielectric profiles. Our approach extends the recently developed high-frequency homogenization theory of hyperuniform media and retrieves more general permittivity profiles for applications-relevant finite-size SHU systems, unveiling unique features related to their isotropic nature. In particular, we demonstrate the existence of a transparency region beyond the long-wavelength approximation, enabling effective and isotropic homogenization even without disorder-averaging, in contrast to the case of uncorrelated Poisson random patterns. We believe that the multiscale network approach introduced here enables the efficient inverse design of general effective media and finite-size metamaterials with isotropic electromagnetic responses beyond the limitations of traditional homogenization theories.
- [33] arXiv:2208.13127 (replaced) [pdf, ps, html, other]
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Title: Observation of stochastic resonance in directed propagation of cold atomsAlexander Staron (1), Kefeng Jiang (1), Casey Scoggins (1), Daniel Wingert (1), David Cubero (2), Samir Bali ((1) Department of Physics, Miami University, Oxford, Ohio, USA (2) Departamento de Fisica Aplicada I, Universidad de Sevilla, Spain)Comments: 9 pages, 7 figuresJournal-ref: Physical Review RESEARCH 4, 043211 (2022)Subjects: Quantum Physics (quant-ph); Atomic Physics (physics.atom-ph); Optics (physics.optics)
Randomly diffusing atoms confined in a dissipative optical lattice are illuminated by a weak probe of light. The probe transmission spectrum reveals directed atomic propagation that occurs perpendicular to the direction of probe beam propagation. Resonant enhancement of this directed propagation is observed as we vary the random photon scattering rate. We experimentally characterize this stochastic resonance as a function of probe intensity and lattice well depth. A simple model reveals how the probe-excited atomic density waves and optical pumping rates conspire to create directed atomic propagation within a randomly diffusing sample.
- [34] arXiv:2311.17362 (replaced) [pdf, ps, html, other]
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Title: Optical Control of Ferroaxial OrderSubjects: Materials Science (cond-mat.mtrl-sci); Optics (physics.optics)
Materials that exhibit ferroaxial order hold potential for novel multiferroic applications. However, in pure ferroaxials, domains are not directly coupled to stress or static electric field due to their symmetry, limiting the ability to pole and switch between domains -- features required for real-world applications. Here we propose a general approach to selectively condense and switch between ferroaxial domains with light. We show that circularly polarized light pulses on resonance with infrared-active phonons manifest helicity-dependent control over ferroaxial domains. Nonlinear contributions to the lattice polarizability play an essential role in this phenomenon. We illustrate the feasibility of our approach using first-principle calculations and dynamical simulations for the archetypal ferroaxial material RbFe(MoO$_4$)$_2$. Our results are discussed in the context of future pump-probe optical experiments, where polarization, carrier frequency, and fluence threshold are explored.
- [35] arXiv:2402.18239 (replaced) [pdf, ps, other]
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Title: Optical Widefield Nuclear Magnetic Resonance MicroscopyKarl D. Briegel, Nick R. von Grafenstein, Julia C. Draeger, Peter Blümler, Robin D. Allert, Dominik B. BucherSubjects: Applied Physics (physics.app-ph); Chemical Physics (physics.chem-ph); Optics (physics.optics); Quantum Physics (quant-ph)
Microscopy enables detailed visualization and understanding of minute structures or processes. While cameras have significantly advanced optical, infrared, and electron microscopy, imaging nuclear magnetic resonance (NMR) signals on a camera has remained elusive. Here, we employ nitrogen-vacancy (NV) centers in diamond as a quantum sensor, which converts NMR signals into optical signals that are subsequently captured by a high-speed camera. Unlike traditional magnetic resonance imaging (MRI), our method records the NMR signal over a wide field of view in real space. We demonstrate that our optical widefield NMR microscopy (OMRM) can image NMR signals in microfluidic structures with a $\sim 10\,\mu m$ resolution across a $\sim 235 \times 150\,\mu m^2$ area. Crucially, each camera pixel records an NMR spectrum providing multicomponent information about the signal's amplitude, phase, local magnetic field strengths, and gradients. The fusion of optical microscopy and NMR techniques enables multifaceted imaging applications in the physical and life sciences.
- [36] arXiv:2404.16901 (replaced) [pdf, ps, other]
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Title: Controllable suppression of Non-Hermitian skin effectsComments: 9 pages and 4 figures in the main text, 6 pages and 7 figures in the supplemental materialSubjects: Mesoscale and Nanoscale Physics (cond-mat.mes-hall); Optics (physics.optics)
The non-Hermitian skin effect (NHSE) is a phenomenon where the bulk states tend to the boundary within a non-Hermitian Hamiltonian system, with broad applications across various fields. A comprehensive understanding of anomalies in skin modes associated with NHSEs is essential for practical applications. Recently, some innovative works reported the suppression and enhancement of NHSEs through the application of magnetic fields, respectively. In our work, we engineered onsite potential energy distribution and found non-monotonic and monotonic suppression patterns on skin modes similar to magnetic fields. These suppression patterns represent characteristic transitions as the onsite potential distribution shifts from order to disorder. Relying only on onsite potential energy engineering, we have not only deepened our insight into the relationship and distinctions between order and disorder, but also developed a general strategy to demonstrate both robustness and controllable adjustability of the skin modes. By integrating with the scaling theory of disorder, we have extended the concept of controllable suppression of NHSEs to higher-dimensional systems.