Output Field Research Articles

Electromagnetically induced transparency and second-order sideband Effects in a Laguerre-Gaussian cavity optorotational system with Kerr medium

Abstract In this paper, we investigate the phenomena of electromagnetically induced transparency (EIT) and the generation of second-order sideband in a Laguerre-Gaussian (LG) cavity optorotational sys tem with a Kerr nonlinear medium. Using the perturbation method, we analyze the first- and second order sideband generations in the output field from the system under the actions of a strong control
field and a weak probe field. Numerical simulations show that the Kerr nonlinearity can lead to the occurrence of the asymmetric line shape in the transmission of the probe field and the efficiency of second-order sideband generation, and the Kerr nonlinearity can enhance the efficiency of the second order sideband generation. Comparing with traditional scheme for generating the second-order sideband, our spectral shape of the second-order sideband is amplified and becomes asymmetric, which has potential applications in precision measurement, high-sensitivity devices, and frequency conversion.

Magneto-optical polarization texturing

Left and right circularly polarized transverse electromagnetic waves propagate at slightly different speeds in a magnetic material leading to a polarization rotation by an amount proportional to the projection of the magnetic field along the direction of the wave propagation. We show how this magneto-optical effect can serve as a vectorial polarization shaper if the input mode is either a radially-polarized or an azimuthally-polarized Laguerre-Gaussian (LG) mode. The specific polarization map of the output field can be achieved by choosing appropriately the magnetic material and/or its geometry. We show further that when the LG beam waist is comparable to the wavelength (i.e. w 0 ≈ λ ) the fields are no longer purely transverse but acquire an additional longitudinal (axial) component. We demonstrate how this modifies the polarization texturing.

A Practical Solver for Scalar Data Topological Simplification.

This paper presents a practical approach for the optimization of topological simplification, a central pre-processing step for the analysis and visualization of scalar data. Given an input scalar field f and a set of "signal" persistence pairs to maintain, our approaches produces an output field g that is close to f and which optimizes (i) the cancellation of "non-signal" pairs, while (ii) preserving the "signal" pairs. In contrast to pre-existing simplification algorithms, our approach is not restricted to persistence pairs involving extrema and can thus address a larger class of topological features, in particular saddle pairs in three-dimensional scalar data. Our approach leverages recent generic persistence optimization frameworks and extends them with tailored accelerations specific to the problem of topological simplification. Extensive experiments report substantial accelerations over these frameworks, thereby making topological simplification optimization practical for real-life datasets. Our approach enables a direct visualization and analysis of the topologically simplified data, e.g., via isosurfaces of simplified topology (fewer components and handles). We apply our approach to the extraction of prominent filament structures in three-dimensional data. Specifically, we show that our pre-simplification of the data leads to practical improvements over standard topological techniques for removing filament loops. We also show how our approach can be used to repair genus defects in surface processing. Finally, we provide a C++ implementation for reproducibility purposes.

Enhancing quantum coherence in hybrid optomechanical systems with coherent feedback, atomic ensembles, and optical parametric amplifier

Abstract We theoretically investigate quantum coherence in a hybrid optomechanical system with a fixed mirror, mechanical oscillators, two-level atoms, and an optical parametric amplifier (OPA) within the cavity. A coherent feedback loop is created by redirecting part of the cavity's output field back into the cavity via an asymmetric beam splitter. Using numerical solutions of the Lyapunov equation and steady-state mean values, we quantify the Gaussian quantum coherence of the system. Our results show that the OPA, coherent feedback, atomic ensembles, and strong laser power significantly enhance quantum coherence, while higher atomic decay rates, relative phase, and temperatures reduce it. This approach not only boosts quantum coherence but also improves resilience to temperature fluctuations, providing a robust foundation for quantum information processing.

Scaling enhancement of photon blockade in output fields

Scaling enhancement of photon blockade in output fields

Improved techniques for the solution of several circular dielectric and hollow layers in a straight rectangular waveguide

The first objective of this research is to develop two effective techniques for solving inhomogeneous problems in a rectangular waveguide with several circular dielectric and hollow layers. The cross section consists of a four-layer periodic circular structure with alternating dielectric and hollow layers. We assume that the dielectric profile is different in each circular dielectric layer. The first technique enables the calculation of the dielectric profile and the elements of the matrices of circular dielectric layers by using the image method. The second alternative technique improves the first technique by using the ω ε function as well as the image method. The second objective is to examine the influence of this discontinuous cross section on the output field. The contribution of the proposed techniques is important to improve the mode model method especially in the case of a large number of circular dielectric and hollow layers in the cross section. The application is useful for an inhomogeneous cross section with several circular dielectric and hollow layers in millimeter regime.

Generating High‐Fidelity Structured Light Fields Through an Ultrathin Multimode Fiber Using Phase Retrieval

AbstractLight transmission through a multimode fiber (MMF) has gained major importance for imaging and manipulation. The majority of phase retrieval algorithms used for a MMF implicitly assume light propagation to be described by a unitary operation, yet the transmission matrix of a multimode fiber is inherently non‐unitary. It is demonstrated that this erroneous assumption can impede the performance of many commonly used MMF phase retrieval algorithms and demonstrate that the weighted Yang–Gu algorithm outperforms other phase retrieval algorithms in this scenario. Once accounted for, the non‐unitary property of the transmission matrix can be leveraged to generate intricate intensity and phase patterns at the output of the fiber, and shape specific output fields. This is experimentally demonstrated by generating Laguerre–Gaussian beams that carry orbital angular momentum, and by forming images in planes offset from the distal end of the fiber facet.

Integratable high-efficiency achromatic metalens across the entire low-loss bands of optical fiber from 1260 to 1625 nm

A challenge in optic fiber is to control dispersion over the entire low-loss bands covering the O + E + S + C + L bands with integratable ultracompact devices, which inevitably limits the range of fiber-based applications. Metalens supplies a dynamic platform for correcting chromatic aberration of optical devices in a flexible, integratable, and ultracompact way. Hence, we propose a broadband achromatic metalens integrated on the end face of a single-mode fiber covering the entire low-loss wavelength region. Utilizing the particle swarm optimization algorithm, we have substantially mitigated the phase-compensated matching error in the achromatic scheme. It demonstrates that the metalens is achievable with achromatic aberration and focuses over the entire low-loss wavelength band with a high mean focusing efficiency of 84.55%. Furthermore, this device exhibits a remarkable capability to break through the diffraction limit of the output field. This work provides a theoretical basis for fiber-integrated achromatic metalens over the entire low-loss bands, which has promising applications in imaging, sensing, and optical communication.

Tunable Fano-type resonance with quadrature squeezing in a double-cavity-waveguide structure of photonic crystals

We propose an optical approach to realizing Fano-type spectra of quadrature squeezing in a double-cavity-waveguide structure based on photonic crystals (PhCs). In this scheme, a partially transmitting element (PTE) in the waveguide creates the transmission and reflection light, which interferes with the outflow from the intracavity field and subsequently gives rise to Fano-type interference. Meanwhile, a degenerate parametric amplifier (DPA) embedded into the cavity is expected to yield quantum squeezed states in the interference process. After verifying the existence of the Fano resonance, we report that increasing the nonlinear gain of the DPA not only amplifies the transmitted intensity of the output field, but also improves its quadrature squeezing degree. More importantly, we illustrate that, when maintaining the high performance of quadrature squeezing, the linewidths and frequencies of the asymmetrical spectra can be modulated by adjusting the double-cavity coupling strength. This combination of Fano-type spectra and quadrature squeezing is beneficial for optimizing optical communications and signal processing with a low noise level.

Tunable multicolor optomechanically induced transparency and slow-fast light in hybrid electro-optomechanical system

Abstract We investigate the tunable multicolor optomechanically induced transparency and the effect of slow/fast light in a hybrid electro-optomechanical system, in which a degenerate optical parametric amplifier (OPA) and a Λ − type three-level atomic ensemble are placed in a optical cavity with two oscillator modes. The system is driven by a strong pump field and a weak probe field, respectively. Multicolor transparency windows appear in the output field under the atom-photon-OPA-phonon-phonon coherent interaction. And the position and width of the transparent port of the output field can be manipulated by properly modifying the different parameters of the subsystem. We also research the slow/fast light effect related to phase and group delay in the probe field. Our proposal provides a great flexibility for phonon storage and has some potential applications in quantum information processing.

The Output Field of Curved Waveguides with a Cross-Section of Alternating Hollow and Dielectric Layers

The aim of this study is to investigate the effects on the output field of curved (helical and toroidal) waveguides having a rectangular cross section made up of seven alternating hollow and dielectric layers. In this study, we will generalize the specific problem of a waveguide with the above cross section from a straight waveguide to both helical and toroidal shaped waveguides. We use a technique based on the inverse transforms of the Laplace and Fourier transforms for this purpose. This study clarifies how the cylinder radius and helix angle affect power transmission and output fields in this particular instance of a periodic cross section. The findings hold true in the microwave and millimeter-wave domains and can be helpful in applications involving helical or toroidal waveguides with periodic arrays of alternating hollow and dielectric layers. The results are true in the microwave and millimeter-wave regimes and can find utility in applications using a periodic array with alternating hollow and dielectric layers in a helical or toroidal waveguide. According to the logical results we get in the output profiles, we can determine what are the logical parameters that should be taken before any experiment in the laboratory that we want to perform. Received: 23 May 2024 | Revised: 25 July 2024 | Accepted: 29 August 2024 Conflicts of Interest The author declares that he has no conflicts of interest to this work. Data Availability Statement Data are available on request from the corresponding author upon reasonable request. Author Contribution Statement Zion Menachem: Conceptualization, Methodology, Software, Formal analysis, Investigation, Resources, Writing - original draft, Supervision.

Thermodynamic sensing of quantum nonlinear noise correlations

Abstract We put forth the concept of quantum noise sensing in nonlinear two-mode interferometers coupled to mechanical oscillators. These autonomous machines are capable of sensing quantum nonlinear correlations of two-mode noisy fields via their thermodynamic variable of extractable work, alias work capacity (WC) or ergotropy. The fields are formed by thermal noise input via its interaction with multi-level systems inside the interferometer. Such interactions amount to the generation of two-mode quantum nonlinear gauge fields that may be partly unknown. We show that by monitoring a mechanical oscillator coupled to the interferometer, one can sense the WC of one of the output field modes and thereby reveal the quantum nonlinear correlations of the field. The proposed quantum sensing method can provide an alternative to quantum multiport interferometry where the output field is unraveled by tomography. This method may advance the simulation and control of multimode quantum nonlinear gauge fields.

Stationary Quantum Entanglement and Asymmetric Steering in Cavity Magnonic System with Floquet Field and Coherent Feedback

AbstractA scheme is proposed to prepare quantum entanglement and quantum steering between two indirectly coupled microwave cavity modes within a hybrid cavity magnonic system. The system consists of two microwave cavities individually coupled to a common YIG sphere driven by a two‐tone Floquet field, while the output field of the second microwave cavity is fed back into the input port of the first microwave cavity via a coherent feedback loop. Floquet driving can effectively generate two interactions between magnons and photons. Magnons with higher dissipation can serve as a cooling channel for the two cavity modes. Optimal quantum correlations between the cavity modes can be achieved when the competition between these two interactions reaches equilibrium. Subsequently, a comparative analysis is performed on the evolution of quantum correlation with and without coherent feedback, revealing that the presence of a coherent feedback loop in the system not only significantly enhances entanglement and steering but also induces inherent asymmetry in quantum steering regardless of the decay rates within subsystems. Moreover, under the influence of the coherent feedback loop, the enhanced quantum correlations exhibit increased robustness against rising environmental temperatures. This work significantly expands the validity of implementation and provides a promising avenue for the preparation of stable quantum correlations.

Coherent feedback ground state cooling of the mechanical resonator in quadratic optomechanical system assisted by an atomic ensemble.

We propose a scheme for cooling a mechanical resonator to its ground state in a quadratic optomechanical system, assisted by an atomic ensemble in the unresolved sideband regime. The system features an auxiliary cavity directly coupled to an optical cavity, with a portion of the optical cavity's output field being fed back through an asymmetric beam splitter. Utilizing quantum Langevin and master equations, we derive the optical fluctuation spectrum, the cooling rate, and the mean phonon number of the mechanical resonator. Our results demonstrate that the feedback mechanism substantially enhances the cooling rate. Furthermore, under optimal cooling conditions, the mechanical resonator achieves ground state cooling even with weaker optomechanical coupling strengths and higher auxiliary cavity dissipation rates, thereby mitigating the experimental constraints associated with these parameters. Additionally, we provide the feasible ranges for optomechanical coupling strength and atomic decay rates. Our findings suggest promising avenues for quantum manipulation in nonlinear systems and its applications in macroscopic optical devices.

Pound–Drever–Hall feedforward: laser phase noise suppression beyond feedback

Pound–Drever–Hall (PDH) laser frequency stabilization is a powerful technique widely used for building narrow linewidth lasers. This technique is, however, ineffective in suppressing high-frequency (>100kHz) laser phase noise detrimental for many applications. Here, we introduce an effective method that can greatly enhance its high-frequency performance. The idea is to recycle the residual PDH signal of a laser locked to a cavity by feedforwarding it directly to the laser output field after a delay fiber. Using this straightforward method, we demonstrate a phase noise suppression capability about four orders of magnitude better than just using the usual PDH feedback for noise around a few MHz. We further find that this method exhibits noise suppression performance equivalent to cavity filtering. This method holds great promise for applications demanding highly stable lasers with diminished phase noise up to tens of MHz (e.g., precise and high-speed control of atomic and molecular quantum states).

Spontaneous symmetry breaking of coupled Fabry–Pérot nanocavities

Ring cavities are quickly emerging as preferential platforms to investigate spontaneous symmetry breaking. However, research on handedness polarisation splitting within Kerr-coupled cavities is yet at a preliminary stage. Here, we observe experimentally spontaneous symmetry breaking in a non-Hermitian coupled Fabry‒Pérot nanocavity. In the experiment, horizontally polarised light is incident on the nanocavities, and symmetry breaking occurs when the power exceeds the symmetry breaking threshold of 8mW\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$8\\,{{\\mbox{mW}}}$$\\end{document}. We interpret such observation via nonlinear coupled mode theory, finding that an excitation power-dependent random splitting of right- or left-handed circular polarisations (RCP and LCP, respectively) emerges at the resonance peak. Further numerical simulations show that when the incident power is above the symmetry breaking threshold, the device exhibits spontaneous symmetry breaking characteristics: an additional polarisation component appears in the output field when the input field is monopolarised, and this is attributed to the imbalance of RCP and LCP. Our findings provide further understanding of spontaneous symmetry breaking in non-Hermitian systems and demonstrate the potential applications of the proposed device in optical signal processing.

Inhomogeneous broadening effects on bistable behavior in a hybrid optomechanical system

Optical bistability is investigated for optomechanical system composed of an ensemble of inhomogeneously broadened two-level atoms embedded between the two mirrors of the optical cavity, that is subjected to two input (strong and probe) fields. We consider two types of inhomogeneous broadened distributions, namely, Lorentzian and Gaussian line shapes. The first order harmonic components of the output fields (due to the presence of probe field) show reversed and knotted bistability shapes simultaneously with the standard bistable shape of the fundamental component of the field at frequency ωc\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\omega _{c}$$\\end{document}. The inhomogeneous broadened line width for both Lorentzian and Gaussian distribution affects the dispersive switching of the system, as well as the bistable behavior. Locations of the maxima of photon numbers associated with higher harmonics of the output fields are identified with respect to the probe field frequency.

All-optical phase conjugation using diffractive wavefront processing

Optical phase conjugation (OPC) is a nonlinear technique used for counteracting wavefront distortions, with applications ranging from imaging to beam focusing. Here, we present a diffractive wavefront processor to approximate all-optical phase conjugation. Leveraging deep learning, a set of diffractive layers was optimized to all-optically process an arbitrary phase-aberrated input field, producing an output field with a phase distribution that is the conjugate of the input wave. We experimentally validated this wavefront processor by 3D-fabricating diffractive layers and performing OPC on phase distortions never seen during training. Employing terahertz radiation, our diffractive processor successfully performed OPC through a shallow volume that axially spans tens of wavelengths. We also created a diffractive phase-conjugate mirror by combining deep learning-optimized diffractive layers with a standard mirror. Given its compact, passive and multi-wavelength nature, this diffractive wavefront processor can be used for various applications, e.g., turbidity suppression and aberration correction across different spectral bands.

Non-Gaussian feature of the output field from a double qubit-cavity ultrastrong coupling system

We investigate the non-Gaussian feature of radiation in a circuit quantum electrodynamics (QED) system where two qubits are strongly coupled to a single-mode cavity. In the regime of ultrastrong coupling (USC), the rotating-wave approximation is not valid, and the Rabi Hamiltonian contains counter-rotating wave terms, leading to level crossing and avoided crossings in the energy spectrum. We further analyze the intensity-amplitude correlation of the output field in these two novel scenarios. In the USC regime, the creation and annihilation operators in the correlation function are replaced, allowing for the identification of non-Gaussian features in the output field. Our findings reveal that despite the absence of squeezing effects in the output light, significant non-Gaussian characteristics are present. Additionally, we demonstrate that as the driving or coupling strength increases, the non-Gaussian features of the output field become more pronounced. This suggests that USC systems hold broad potential applications in the realms of nonlinear optics and the generation of non-Gaussian states.

All-optical complex field imaging using diffractive processors.

Complex field imaging, which captures both the amplitude and phase information of input optical fields or objects, can offer rich structural insights into samples, such as their absorption and refractive index distributions. However, conventional image sensors are intensity-based and inherently lack the capability to directly measure the phase distribution of a field. This limitation can be overcome using interferometric or holographic methods, often supplemented by iterative phase retrieval algorithms, leading to a considerable increase in hardware complexity and computational demand. Here, we present a complex field imager design that enables snapshot imaging of both the amplitude and quantitative phase information of input fields using an intensity-based sensor array without any digital processing. Our design utilizes successive deep learning-optimized diffractive surfaces that are structured to collectively modulate the input complex field, forming two independent imaging channels that perform amplitude-to-amplitude and phase-to-intensity transformations between the input and output planes within a compact optical design, axially spanning ~100 wavelengths. The intensity distributions of the output fields at these two channels on the sensor plane directly correspond to the amplitude and quantitative phase profiles of the input complex field, eliminating the need for any digital image reconstruction algorithms. We experimentally validated the efficacy of our complex field diffractive imager designs through 3D-printed prototypes operating at the terahertz spectrum, with the output amplitude and phase channel images closely aligning with our numerical simulations. We envision that this complex field imager will have various applications in security, biomedical imaging, sensing and material science, among others.