Yingwen Zhang, Paul-Antoine Moreau, Duncan England
et al.
Abstract We present an entanglement-based quantitative phase gradient microscopy technique that employs principles from quantum ghost imaging and ghost diffraction. In this method, a transparent sample is illuminated by both photons of an entangled pair–one detected in the near-field (position) and the other in the far-field (momentum). Due to the strong correlations offered by position-momentum entanglement, both conjugate observables can be inferred nonlocally, effectively enabling simultaneous access to the sample’s transmission and phase gradient information. This dual-domain measurement allows for the quantitative recovery of the full amplitude and phase profile of the sample. Unlike conventional classical and quantum phase imaging methods, our approach requires no interferometry, spatial scanning, microlens arrays, or iterative phase-retrieval algorithms, thereby circumventing many of their associated limitations. Furthermore, intrinsic temporal correlations between entangled photons provide robustness against dynamic and structured background light. We demonstrate quantitative phase and amplitude imaging with a spatial resolution of 2.76 μm and a phase sensitivity of λ/100 using femtowatts of illuminating power. This technique opens new possibilities for non-invasive imaging of photosensitive samples, wavefront sensing in adaptive optics, and imaging under complex lighting environments.
Abstract Deterministic three-dimensional (3D) super-resolution microscopy can achieve light-matter interaction in a small volume, but usually with the axial extension distinctly more elongated than the lateral one. The isoSTED method combining two opposing objectives and multiple laser beams can offer high axial extension at λ/12 level, but at the cost of optical system complexity and inherent sidelobes. The high-order nonlinear effect by multiphoton excitation would benefit to achieve a sub-diffraction resolution as well as to suppress the sidelobes. Herein, to achieve an easy-to-use, sidelobe-free deterministic 3D nanoscopy with high axial resolution, we developed a purely physical deterministic strategy (UNEx-4Pi) by fusion of ultrahighly nonlinear excitation (UNEx) of photon avalanching nanoparticles and mirror-based bifocal vector field modulation (4Pi). The theoretical studies of UNEx-4Pi concept showed that the main peak of fluorescence spot became sharper and its large sidelobe height was suppressed with the increasing optical nonlinearity. In addition, the simplicity and robustness of UNEx-4Pi system were demonstrated utilizing a mirror-assisted single-objective bifocal self-interference strategy. Experimentally, UNEx-4Pi realized an extremely constringent focal spot without sidelobes observed, achieving an axial resolution up to λ/33 (26 nm) using one low-power CW beam. We also demonstrated the super-resolution ability of the UNEx-4Pi scheme to bioimaging and nuclear envelope of BSC-1 cells were stained and imaged at an axial resolution of 32 nm. The proposed UNEx-4Pi method will pave the way for achieving light-matter interaction in a highly confined space, thereby advancing cutting-edge technologies like deterministic super-resolution sensing, imaging, lithography, and data storage.
We theoretically and numerically investigate helical Ince-Gaussian modes, hIGp,q(x, y, ε). Explicit analytical expressions are derived that describe dependence of the orbital angular momentum of the helical Ince-Gaussian modes at p=2, 3, 4, 5 on the ellipticity parameter ε. For this purpose, the earlier obtained expansions of Ince-Gaussian modes in terms of Hermite-Gaussian modes are used. We demonstrate that in general the orbital angular momentum is an even function of ε, which changes non-monotonically when ε varies from zero to infinity. At zero ε, the orbital angular momentum is equal to the index q of the Ince-Gaussian mode, whereas at ε=∞, the orbital angular momentum is [q(p–q+1)]1/2. Topological charge of the helical Ince-Gaussian mode depends on ε and is equal to the index q at ε=0 and to the index p at ε=∞.
Marcelo F. Ciappina, Misha Yu. Ivanov, Maciej Lewenstein
et al.
In its beginnings, the physics of intense laser-matter interactions was the physics of multiphoton processes. The theory was reduced then to high-order perturbation theory, while treating matter and light in a quantum manner. With the advent of chirped pulse amplification developed by D. Strickland and G. Mourou, which enabled generation of ultra-intense, ultra-short, coherent laser pulses, the need for a quantum electrodynamics description of electromagnetic (EM) fields practically ceased to exist and lost relevance. Contemporary attoscience (AS), and more generally ultrafast laser physics, awarded the Nobel Prize in 2023 to P. Agostini, F. Krausz, and A. L'Huillier, commonly uses the classical description of EM fields while keeping a fully quantum description of matter. The progress and successes of AS in the last 40 years have been spectacular, with an enormous amount of fascinating investigations in basic research and technology. Yet a central question remains: can ultrafast laser physics continue to advance without reintroducing quantum electrodynamics and quantum optics into its description of light-matter interactions? This article discusses future perspectives at the intersection of strong-field physics and quantum optics.
Mahdi Rahmanpour, Alireza Erfanian, Ahmad Afifi
et al.
The most important goal of quantum communication is to distribute the encryption key between the transmitter and the receiver. The optimal situation in Quantum Key Distribution (QKD) between transmitter and receiver is to increase the key distribution rate per second, increase the transmission distance, and reduce the error in key distribution. Several protocols used for QKD. The most important of QKD protocols is the BB84. One of the challenges leading to errors in quantum protocols is generating error pulses in single-photon detectors. These pulses caused by the inherent effects of quantum devices. They can cause wrong detection in the receiver. Many measures have been taken in the design and construction of single-photon detectors to reduce this error pulses, but it is not possible to eliminate all of them. Afterpulse and dark counts are two types of unwanted pulses that occur with single-photon detectors. In this paper, a new QKD protocol is proposed. It is an upgrade of the BB84 protocol and can reduce the effects of unwanted pulses such as afterpulse and dark counts in QKD avalanche detectors.
The point charge electrostatic model (PCEM) and the simple overlap model (SOM), both purely analytical crystal field models, are being briefly revisited, in order to show the evolution of their application to Eu doped compounds. Calculations are made through the method of equivalent nearest neighbours (MENN), and applied to the Eu(dipivaloylmethanate)31,10-phenanthroline [Eu(DPM)3o-phen] complex, with the aim of discussing the Eu–O and Eu–N interactions. The charge of the Eu ion is calculated using the Batista-Longo improved model (BLIM) to give gBLIM = 3,64e around the Eu-NN midpoint. The 7F1 crystal-field levels and level splitting were satisfactorily reproduced with two charge factors, namely, g1 = 0.495 and g2 = 0.415, assuming the luminescent site in a tetragonal point symmetry slightly distorted. In particular, it is shown that the Eu3+, itself, is satisfied by attracting an amount of charge, which neutralize/stabilize its own site electrostatically, no matter what the ligating ions are. The Eu-NN overlap (ρ = <4f|2s2p>) is assumed to be 0.1, which is physically plausible both as a limit in respect to β, the SOM correction factor to the PCEM, and describes the covalent contribution to the Ln-NN interaction, the latter is the most important contribution of the SOM to the crystal-field theory of lanthanide containing compounds. An eloquent comparison with crystal-field levels of the Eu:LiYF4 and Eu(btfa)3(4,4-bipy)(EtOH) is made. Finally, this paper is, indeed, a very simple tribute to Professor Oscar L. Malta, as an acknowledgement of his deep contribution to the author's apprenticeship about crystal-field theory of systems containing lanthanides.
Pierre Koleják, Geoffrey Lezier, Daniel Vala
et al.
Optically pumped spintronic terahertz emitters (STEs) have, in less than a decade, strongly impacted terahertz (THz) source technology, by the combination of their Fourier‐limited ultrafast response, their phononless emission spectrum and their wavelength‐independent operation. However, the intrinsic strength of the inverse spin Hall effect governing these devices introduces a challenge: the optical‐to‐terahertz conversion efficiency is considerably lower than traditional sources. It is therefore primordial to maximize at least their electromagnetic efficiency independently of the spin dynamics at play. Using a rigorous time‐domain treatment of the electromagnetic generation and extraction processes, an optimized design is presented and experimentally confirmed. With respect to the strongest reported spintronic THz emitters it achieves a 250% enhancement of the emitted THz field and therefore an 8 dB increase of emitted power. This experimental achievement brings STE close to the symbolic barrier of mW levels. The design strategy is generically applicable to any kind of ultrafast spin‐to‐charge conversion (S2C) system. On a broader level, our work highlights how a rigorous handling of the purely electromagnetic aspects of THz spintronic devices can uncover overlooked aspects of their operation and lead to substantial improvements.
In this study, Eu:6LiBr/BaBr2 with a high Li concentration was developed as a novel neutron scintillator. Here, an Eu-doped BaBr2 phase acted as a scintillator and 6Li-containing LiBr phase acted as a neutron capturer. Eu:6LiBr/BaBr2 eutectics were fabricated via the vertical Bridgman technique in quartz ampoules. The scintillation performance of Ce:6LiBr/LaBr3 was measured using electron and neutron irradiation to evaluate its potential as a neutron scintillator. The grown Eu:6LiBr/BaBr2 eutectic exhibited a lamellar eutectic structure and optical transparency as well as a 410 nm emission due to the Eu2+ 5d–4f transition. The light yield under thermal neutron excitation was estimated to be 5600 photons/neutrons. The scintillation decay time was 550 ns.
Nicholas J. Sorensen, Michael T. Weil, Jeff S. Lundeen
Recently introduced, spaceplates achieve the propagation of light for a distance greater than their thickness. In this way, they compress optical space, reducing the required distance between optical elements in an imaging system. Here we introduce a spaceplate based on conventional optics in a 4-$f$ arrangement, mimicking the transfer function of free-space in a thinner system - we term this device a three-lens spaceplate. It is broadband, polarization-independent, and can be used for meter-scale space compression. We experimentally measure compression ratios up to 15.6, replacing up to 4.4 meters of free-space, three orders of magnitude greater than current optical spaceplates. We demonstrate that three-lens spaceplates reduce the length of a full-color imaging system, albeit with reductions in resolution and contrast. We present theoretical limits on the numerical aperture and the compression ratio. Our design presents a simple, accessible, cost-effective method for optically compressing large amounts of space.
A. V. Andrianov, N. A. Kalinin, A. A. Sorokin
et al.
Bright squeezed light can be generated in optical fibers utilizing the Kerr effect for ultrashort laser pulses. However, pulse propagation in a fiber is subject to nonconservative effects that deteriorate the squeezing. Here, we analyze two-mode polarization squeezing, which is SU(2)-invariant, robust against technical perturbations, and can be generated in a polarization-maintaining fiber. We perform a rigorous numerical optimization of the process and the pulse parameters using our advanced model of quantum pulse evolution in the fiber that includes various nonconservative effects and real fiber data. Numerical results are consistent with experimental results.
Aleksandar Haber, John E. Draganov, Michael Krainak
In this paper, we investigate the feasibility of using subspace system identification techniques for estimating transient Structural-Thermal-Optical Performance (STOP) models of reflective optics. As a test case, we use a Newtonian telescope structure. This work is motivated by the need for the development of model-based data-driven techniques for prediction, estimation, and control of thermal effects and thermally-induced wavefront aberrations in optical systems, such as ground and space telescopes, optical instruments operating in harsh environments, optical lithography machines, and optical components of high-power laser systems. We estimate and validate a state-space model of a transient STOP dynamics. First, we model the system in COMSOL Multiphysics. Then, we use LiveLink for MATLAB software module to export the wavefront aberrations data from COMSOL to MATLAB. This data is used to test the subspace identification method that is implemented in Python. One of the main challenges in modeling and estimation of STOP models is that they are inherently large-dimensional. The large-scale nature of STOP models originates from the coupling of optical, thermal, and structural phenomena and physical processes. Our results show that large-dimensional STOP dynamics of the considered optical system can be accurately estimated by low-dimensional state-space models. Due to their low-dimensional nature and state-space forms, these models can effectively be used for the prediction, estimation, and control of thermally-induced wavefront aberrations. The developed MATLAB, COMSOL, and Python codes are available online.
Abstract Analogous to the behavior of a common converging lens for the input of tilted waves, a recent publication suggests a new optical element with an azimuthal-quadratic phase profile for the focusing of orbital angular momentum beams at distinct angular positions. Its realization in a metasurface form enables the combined measurement of orbital and spin angular momentum using a single optical component.