Elcro-optomechanical entanglement in two coupled optical cavities with LC microwave circuit

Shabnam Abutalebi B.A., Ali Asghari Nejad, Hassan Askari, and Alireza Bahrampour

DOI: 10.1364/JOSAB.519837 Received 25 Jan 2024; Accepted 23 Apr 2024; Posted 23 Apr 2024  View: PDF

Abstract: We theoretically investigate entanglement in a hybrid quantum system comprising two optical cavities coupled to a shared microwave cavity via optomechanical interactions. Our results demonstrate that increasing the microwave input power and frequency in allowed range enhances entanglement between the microwave-optical and optical-optical modes. we also show by change frequency of the one optical cavity in communication domain we still have entanglement. This ability to generate robust microwave-optical photon entanglements shows promise for various quantum technologies. Optical photons could enable secure quantum communication in optical fibers, while microwave photons allow transmission to satellites. Overall, this hybrid cavity optomechanical system offers prospects as an efficient source of entangled photon pairs, vital for implementing long-distance quantum communication networks.

Accurate measurement of THz beam radius through eclipsing mask-pattern and photoconductive antenna detector

Osamu Morikawa, Ai Hattori, Kohji Yamamoto, Kazuyoshi Kurihara, Takashi Furuya, Fumiyoshi Kuwashima, Hideaki Kitahara, and Masahiko Tani

DOI: 10.1364/JOSAB.522107 Received 22 Feb 2024; Accepted 22 Apr 2024; Posted 22 Apr 2024  View: PDF

Abstract: In a terahertz (THz) time-domain spectroscopic system, the THz beam waist radius can be measured by eclipsing the beam waist while monitoring signal variation. For instance, the method employing a semi-infinite mask is termed the “knife-edge” method. However, the obtained beam waist radius is affected by the spatial distribution of the detector sensitivity. This effect was confirmed by applying the beam waist radius to calculate the refractive-index correction required when inserting a sample into the beam waist. The real beam waist radius was √2 times larger than that obtained by differentiating the signal variation in a system comprising optics symmetrical about the beam waist.

Influence of adhesion layers on optical losses in THz quantum cascade lasers

Dmitrii Ushakov, Alexander Afonenko, Rustam Khabibullin, Vladimir Gavrilenko, and Alexander Dubinov

DOI: 10.1364/JOSAB.515180 Received 04 Dec 2023; Accepted 22 Apr 2024; Posted 22 Apr 2024  View: PDF

Abstract: For a GaAs/AlGaAs terahertz (THz) quantum cascade laser (QCL) with a double metal waveguide (DMWG) based on Au and Cu metal plates and Ti and Ta adhesion layers, the dumping parameters and THz mode loss spectra were calculated. It has been shown that to minimize losses in high-temperature DMWG QCL designs, it is advisable to use Ti less than 5 nm thick or Ta less than 10 nm thick as adhesion layers for Au. The use of the proposed waveguide with a thickness of 20 μm will lead to the creation of a room temperature THz QCL.

Canonical and Poynting currents in propagation and diffraction of structured light: tutorial

Bohnishikha Ghosh, Anat Daniel, Bernard Gorzkowski, Aleksandr Bekshaev, Radek Lapkiewicz, and Konstantin Bliokh

DOI: 10.1364/JOSAB.522393 Received 29 Feb 2024; Accepted 19 Apr 2024; Posted 22 Apr 2024  View: PDF

Abstract: Local propagation and energy flux in structured optical fields is often associated with the Poynting vector. However, the local phase gradient (i.e., local wavevector) in monochromatic fields in free space is described by another fundamental quantity: the canonical momentum density. The distributions of the Poynting and canonical momentum densities can differ significantly from each other in structured fields. We examine the role of these quantities in the propagation and diffraction of structured optical fields, exemplified by various circularly-polarized vortex beams carrying orbital angular momentum. We describe the canonical and Poynting momentum distributions in such beams, experimentally measure the local transverse momentum density by Shack-Hartmann wavefront sensor, and investigate fine features of the diffraction of various vortex beams on a knife-edge aperture. In all cases, the measured local momentum density and local beam evolution are consistent with the canonical momentum distribution rather than the Poynting vector. Furthermore, we introduce the local angular velocity in vortex beams and determine the universal integral $\pi$ angle of azimuthal rotation in an arbitrary (yet circularly-symmetric) propagating and diffracting vortex beam. Finally, we discuss the `supermomentum' and `backflow' effects; both of these phenomena are examples of superoscillations and are related to the properties of the canonical momentum. Our results reveal the profound role of the canonical momentum in the evolution of light and demonstrate the importance of distinguishing between it and the Poynting vector in structured light.

How is photon-blockade breakdown different from optical bistability? A neoclassical story

Árpád Kurkó, András Vukics, and Német Nikolett

DOI: 10.1364/JOSAB.522547 Received 29 Feb 2024; Accepted 19 Apr 2024; Posted 22 Apr 2024  View: PDF

Abstract: The photon-blockade breakdown bistability can be intuitively explained invoking the energy spectrum of the interacting qubit-mode system. Yet, the neoclassical solution of the driven–dissipative Jaynes–Cummings model has been shown to capture several key aspects of the phenomenon. In this paper, we set out to compare a fully quantum solution with the neo- and semiclassical solutions. Although the neoclassical theory is founded on the assumption of a pure partial state for the qubit, it is not simply the γ → 0 limit of the semiclassical theory; the semi- vs. neoclassical duality being a case of non-commutativity of limits. Furthermore, we show that the neoclassical predictions still hold in case of a small qubit decay. Tracing the bistable behavior for different detunings, we show that it is robust over a significant range of Δ values. We demonstrate that the aptitude of the neoclassical description is founded on the high quantum purity of the bright state of the photon-blockade breakdown bistability, which sharply differentiates this phenomenology from conventional optical bistability. It is thereby demonstrated that driven–dissipative dynamics can produce closely separable pure steady states in an interacting bipartite.

Effect of spin-orbit coupling and impurities on the optical properties of double quantum rings under magnetic fields

Xiongkang Shao

DOI: 10.1364/JOSAB.524354 Received 20 Mar 2024; Accepted 16 Apr 2024; Posted 19 Apr 2024  View: PDF

Abstract: In this paper, the energy spectrum of concentric double quantum rings (CDQRs) with double wellconfinement under the influence of spin-orbit interactions (SOIs), magnetic fields and hydrogen donorimpurities is studied by using the diagonalization and perturbation theory of Hamiltonian matrix.The light absorption coefficient is then calculated in the form of a compactness density-matrix.Key findings from this study include the ability to manipulate fine energy level splitting and opticalabsorption coefficients by tuning the magnetic field, impurity position, spin-orbit coupling, and innerring size. Furthermore, this study reveals the bleaching effect of the optical absorption coefficientunder certain conditions and demonstrates the anisotropic nature of the system through changes in theoptical absorption coefficients(OACs) for different incident light polarization angles.

Generation of stationary entanglement and quantum discord in optomechanical system through three-level atoms

ABRAHAM KIBRET, Tewodros Darge, and Tesfay Gebremariam Tesfahannes

DOI: 10.1364/JOSAB.516660 Received 20 Dec 2023; Accepted 15 Apr 2024; Posted 16 Apr 2024  View: PDF

Abstract: In this paper, we investigate the stationary entanglement and quantum discord between the cavity and mechanical oscillator mode of an optomechanical system whose cavity contains three-level atoms. We examine how sharing entanglement and correlations would be affected by increasing the level of atoms injected into the cavity. In particular, using the appropriate preference of injected atoms to the cavity and optical cavity detuning, we found that the impact of atoms and couplings on the degree of steady-state entanglement and quantum discord. Consequently, the stationary entanglement and quantum discord shared rise to a certain range of normalized detuning and atom injection levels. Furthermore, both entanglement and Gaussian quantum discord are enhanced when three-level atoms are present, and the maximum entanglement manifests closest to the ringing case. Moreover, we are aware that the system's physical parameters affect the generation of stationary entanglement and quantum correlation. Therefore, these results may provide a platform for a valuable asset in the practical realization of continuous variable entanglement and quantum information processing.

Successive quasienergy collapse and the driven Dicke phase transition in the few-emitter limit

Therese Karmstrand, Göran Johansson, and Ricardo Gutierrez-Jauregui

DOI: 10.1364/JOSAB.522611 Received 29 Feb 2024; Accepted 13 Apr 2024; Posted 15 Apr 2024  View: PDF

Abstract: The emergent behavior that arises in many-body systems of increasing size follows universal laws that become apparent in order-to-disorder transitions. While this behavior has been traditionally explored for large numbers of emitters, recent progress allows for the exploration of the few-emitter limit, where correlations can be measured and connected to microscopic models to gain further insight into order-disorder transitions. We explore this few-body limit in the driven and damped Tavis–Cummings model, which describes a collection of atoms interacting with a driven and damped cavity mode. Our exploration revolves around the dressed states of the atomic ensemble and field, whose energies are shown to collapse as the driving field is increased to mark the onset of a dissipative quantum phase transition. The collapse occurs in stages and is an effect of light-matter correlations that are overlooked for single atoms and neglected in mean-field models. The implications of thesecorrelations over the macroscopic observables of the system are presented. We encounter a shift in the expected transition point and an increased number of parity-broken states to choose from once the ordered phase is reached.

Spectroscopic study of the $\bm{4f^{7}6s^{2}\;{}{ }^8S^\circ_{7/2} - 4f^{7}({}^{8}S^\circ)6s6p ({}^{1}P^\circ)\: {}^8P_{5/2,7/2}}$ transitions in neutral europium-151 and europium-153: absolute frequency and hyperfine structure

Chitose Maruko, Nisa Colmek, Maria Teresa Herd, Karl Ahrendsen, Barbara Cabrales, Gaven Cannon, Emma Davis, Xinyun Guo, Tilila Karani, Allie Wallace, Katarzyna Wisnauckas, and William Williams

DOI: 10.1364/JOSAB.521181 Received 07 Feb 2024; Accepted 12 Apr 2024; Posted 12 Apr 2024  View: PDF

Abstract: We report on spectroscopic measurements on the $4f^{7}6s^{2}\;{}{ }^8S^\circ_{7/2} \ - \ 4f^{7}({}^{8}S^\circ)6s6p ({}^{1}P^\circ)\: {}^8P_{5/2,7/2}$ transitions at 466.32 nm and 462.85 nm, respectively, in neutral europium-151 and europium-153. The center of gravity frequencies for the 151 and 153 isotopes for both transitions are reported for the first time using saturated absorption spectroscopy. For the $6s6p ({}^{1}P^\circ)\: {}^8P_{5/2}$ state, the center of gravity frequencies were found to be 642,894,493.3(4) MHz and 642,891,693.3(9) MHz for the 151 and 153 isotopes, respectively. The hyperfine constants for the upper state were found to be A(151) = -157.01(3) MHz, B(151)= 74.5(4) MHz and A(153) = -69.43(14) MHz, B(153)= 191.0(26) MHz. These hyperfine values are all consistent with previously published results except for B(151) that has a small discrepancy. The isotope shift was found to be 2,799.54(20) MHz, a small discrepancy with previously published results. For the $6s6p ({}^{1}P^\circ)\: {}^8P_{7/2}$ state, the center of gravity frequencies were found to be 647,708,930.6(6) MHz and 647,705,958.4(26) MHz for the 151 and 153 isotopes, respectively. The hyperfine constants for the upper state were found to be A(151) = -218.66(4) MHz, B(151)= -293.1(2) MHz and A(153) = -97.15(13) MHz, B(153)= -750(3) MHz. These values are all consistent with previously published results except for A(151) that has a small discrepancy. The isotope shift was found to be 2,972.8(5) MHz, a small discrepancy with previously measured results.

Optical transition properties, 1550 nm-to-980 nm upconversion, and temperature sensing of NaEr(WO4)2:Yb3+ phosphors synthesized via microwave-assisted hydrothermal method

Duan Gao, Shengyi Liu, Xizhen Zhang, jinsu zhang, Sai Xu, Xiangping Li, Yongze Cao, Yichao Wang, Hongquan Yu, Yuhang Zhang, Xuezhu Sha, Li Wang, Xin Chen, and Baojiu Chen

DOI: 10.1364/JOSAB.522641 Received 29 Feb 2024; Accepted 12 Apr 2024; Posted 12 Apr 2024  View: PDF

Abstract: Improving photoelectric conversion efficiency and enhancing heat management are two critical considerations for silicon-based solar cells. In this study, efficient Yb3+ infrared emissions through the upconversion process were achieved by adjusting the concentrations of Yb3+ in Er3+ highly condensed NaEr(WO4)2 phosphor. Additionally, the temperature sensing based on the fluorescence intensity ratio (FIR) was also studied in this tungstate system. Moreover, the radiative transition rates for all interested transitions of Er3+ in NaEr(WO4)2:Yb3+ phosphors were calculated in the framework of Judd-Ofelt theory, and the optical transition properties of Yb3+ were also revealed by taking Er3+ as a reference. It was found that the radiative transition rate of Yb3+:2F5/2→2F7/2 (2977.52 s-1) is significantly higher than that of Er3+:4I11/2→4I15/2 (303.50 s-1), thus suggesting the feasibility for the strong emission at 980 nm of Yb3+ in assistance of the energy transfer 4I11/2+2F7/2→4I15/2+2F5/2. Finally, strong and nearly pure NIR emissions of Yb3+ was experimentally observed under 1550 nm excitation, and possible upconversion mechanisms were proposed. The temperature sensing performance of the studied materials was also assessed. All the results imply that NaEr(WO4)2:Yb3+ constitutes an excellent material for enhancing both the photoelectric conversion efficiency and thermal management of silicon-based solar cells.

Ultrafast dephasing in solid state high harmonic generation: macroscopic origin revealed by real-space dynamics

Graham Brown, Alvaro Jimenez-Galan, Rui Emanuel Ferreira da Silva, and Misha Ivanov

DOI: 10.1364/JOSAB.513543 Received 20 Nov 2023; Accepted 12 Apr 2024; Posted 12 Apr 2024  View: PDF

Abstract: Using a fully real-space perspective on high harmonic generation (HHG) in solids, we examine the relationship between microscopic response, macroscopic propagation of this response to the far field, and the extremely short dephasing times routinely used in the theoretical simulations of experimentally measured solid-state HHG spectra. We find that far field propagation naturally reduces the contribution to the observed HHG emission from electrons that do not return to the lattice site where they have been injected into the conduction band. We then show that extremely short dephasing times routinely used in microscopic simulations suppress many electron trajectories that contribute to the far-field spectra, leading to significant distortions of the true high harmonic response. We show that a real-space based dephasing mechanism, which preferentially suppresses trajectories which veer too far away from their original lattice site, yield HHG spectra that faithfully retain those trajectories that contribute to the far-field spectra while filtering out those which do not, already at the microscopic level. Our findings emphasize the similarities between atomic and solid- state HHG by highlighting the importance of the intensity-dependent phase of HHG emission and address the longstanding issue regarding the origin of extremely short dephasing times in solid-state HHG.

Investigation of spectro-temporal high-order sideband generation from transition metal dichalcogenides

Yaxin Liu, Shicheng Jiang, Bingbing Zhu, Sheng Zhang, Weifeng Liu, and Zhensheng Tao

DOI: 10.1364/JOSAB.520032 Received 29 Jan 2024; Accepted 11 Apr 2024; Posted 12 Apr 2024  View: PDF

Abstract: High-order sideband emission (HSE) in semiconductors under intense terahertz fields has been extensively studied, because it provides essential information for studying ultrafast dynamics in strong-field-dressed quantum materials. In particular, transition metal dichalcogenides (TMDCs), characterized by their unique band structures, provides an exemplary semiconductor system to explore the influence of material band structure on strong-field-induced modulation of HSE. In this work, we investigate the spectro-temporally resolved HSE from different bulk TMDC materials. Our results reveal distinct temporal HSE spectra, which can be attributed to the different absorption behaviors of these materials. Simulations based on the strong-field approximation and Floquet theory can well reproduce the experimental observations. Our work also delves into the spectro-temporal interference that emerges when neighboring harmonic orders overlap in HSE spectrum. This work enhances our understanding of high-order sideband dynamics in strong-field-dressed semiconductors, offering insights for applications in spectrum- and phase-resolved ultrafast measurements.

Compact adiabatic mode (de)multiplexer assisted by subwavelength structures in the silicon-on-insulator platform

Jing Long, Xiaochun Liu, and Changshui Chen

DOI: 10.1364/JOSAB.518688 Received 19 Jan 2024; Accepted 11 Apr 2024; Posted 11 Apr 2024  View: PDF

Abstract: Mode division multiplexing technology holds great promise for addressing the ever-increasing demand for data transmission capacity. This paper proposes a subwavelength-structure-assisted adiabatic mode (de)multiplexer based on the silicon-on-insulator platform, designed for TE0, TE1, and TE2 modes. Adiabatic mode (de)multiplexers have the advantages of broad bandwidth and large fabrication tolerance. However, conventional adiabatic mode (de)multiplexers necessitate a long evolution length. By introducing subwavelength structures, the coupling strength of the adiabatic mode multiplexer can be enhanced, significantly reducing the evolution length. The adiabatic evolution lengths for TE0-TE1 and TE0-TE2 processes are only 11.25 μm and 25 μm, respectively. To the best of our knowledge, these are the shortest evolution lengths for TE0-TE1 and TE0-TE2 processes among all adiabatic mode (de)multiplexers. The numerical simulation shows that the operating bandwidth of the proposed device is beyond 200 nm. In the whole wavelength range of 1450-1650 nm, the insertion losses are for TE0-TE0, TE0-TE1, and TE0-TE2 processes less than 0.05 dB, 0.09 dB, and 0.15 dB respectively, and the mode crosstalk is less than -26.0 dB, -25.9 dB, and -26.1 dB respectively. Additionally, the device can be expanded to accommodate higher-order modes by cascading additional adiabatic mode (de)multiplexers.

Simple strategy for simulation of large area of axially symmetric metasurfaces

Augusto Martins, Achiles Fontana da Mota, Chris Stanford, Taylor Contreras, Justo Martin-Albo, Alexander Kish, Carlos Ourivio Escobar, Adam Para, and Roxanne Guenette

DOI: 10.1364/JOSAB.510725 Received 06 Nov 2023; Accepted 09 Apr 2024; Posted 09 Apr 2024  View: PDF

Abstract: Metalenses are composed of nanostructures for focusing light and have been widely explored in many exciting applications. However, their expanding dimensions pose simulation challenges. We propose a method to simulate metalenses in a timely manner using vectorial wave and ray tracing models. We sample the metalens' radial phase gradient and locally approximate it by a linear phase response. Each sampling point is modeled as a binary blazed grating, employing the chosen nanostructure, to build a transfer function set. The metalens transmission or reflection is then obtained by applying the corresponding transfer function to the incoming field on the regions surrounding each sampling point. Fourier optics is used to calculate the scattered fields under arbitrary illumination for the vectorial wave method and a Monte Carlo algorithm is used in the ray tracing formalism. We validated our method against finite difference time domain simulations at 632 nm and we were able to simulate metalenses larger than 3000λ₀ in diameter on a personal computer.

Band Gap Engineering and Controlling Transport Properties of Single Photons in Periodic and Disordered Jaynes-Cummings Arrays

Tiberius Berndsen, Amgain Nishan, and Imran Mirza

DOI: 10.1364/JOSAB.520000 Received 29 Jan 2024; Accepted 08 Apr 2024; Posted 09 Apr 2024  View: PDF

Abstract: We theoretically study the single photon transport properties in periodic and position-disordered Jaynes-Cummings (or JC) arrays of waveguide-coupled microtoroidal ring resonators, each interacting with a single two-level quantum emitter. Employing the real-space formalism of quantum optics, we focus on various parameter regimes of cavity quantum electrodynamics (cQED) to gain better control of single photon propagation in such a many-body quantum optical setting. As for some of the key findings, we observe that the periodic setting leads to the formation of the band structure in the photon transmission spectra, which is most evident in the strong coupling regime of cQCD. However, under the resonant conditions with no losses, the application of Bloch's theorem indicates that the width of forbidden gaps can be altered by tuning the emitter-cavity coupling to small values. Moreover, in the disordered case, we find that the single photon transmission curves show the disappearance of band formation. However, spectral features originating from cQED interactions observed for single atom-cavity problem remain robust against weak-disordered conditions. The results of this work may find application in the study of quantum many-body effects in the optical domain as well as in different areas of quantum computation and quantum networking.

A Deep Learning Method for Optical Fiber Curvature Measurements Based on Time Series Data

Brian Pamukti, Muhammad Fajar Faliasthiunus Pradipta, Shien-Kuei Liaw, Fu-Liang YANG, and Ya-Mei Yang

DOI: 10.1364/JOSAB.517639 Received 08 Jan 2024; Accepted 07 Apr 2024; Posted 08 Apr 2024  View: PDF

Abstract: Curvature detection is essential technique for monitoring landslides, which are frequent and destructive disasters. Existing methods for curvature detection using fiber-optic sensors have limitations such as complex fabrication or high data size. We propose data processing method for high-accuracy curvature detection that employs deep learning. We experiment using different levels of curvature and compare our method with other methods. Our method achieves 99.82% accuracy for classification and a low root mean square error (RMSE) of 0.042 m-1 for regression with a simpler structure and lower data size. Our approach also demonstrates its potential for landslide detection and communication systems integration.

t-DMRG Simulation of Kerr Nonlinearity; Analyzing Initial State Dependency of non-Gaussian Dynamics

souvik agasti

DOI: 10.1364/JOSAB.519373 Received 18 Jan 2024; Accepted 03 Apr 2024; Posted 04 Apr 2024  View: PDF

Abstract: We simulate a free dissipative and coherent-driven Kerr nonlinear system using a time-evolving block decimation (TEBD) algorithm, to study the impact of the initial state on the exact dynamics of the system. Thesuperposition of two coherent branches results in non-classical time dynamics. The Wigner state representationconfirms that the system ends up saturating to two different branches, through evolving different trajectories,resulting in de-Gaussification throughout evolution. Furthermore, we also see that the time evolution suffers aresidual effect of the initial state.

Controllable nonlinear effects in hybrid magnonical semiconductor microcavity

VIJAY BHATT, Madhav Singh, Anju Agrawal, Pradip Jha, and Aranya Bhattacherjee

DOI: 10.1364/JOSAB.519406 Received 19 Jan 2024; Accepted 21 Mar 2024; Posted 04 Apr 2024  View: PDF

Abstract: We investigate theoretically the bistability properties of the hybrid optomechanical system embedded with magnon. The system is driven by amplitude modulated pump laser. We provide an analytical framework for handling this modulation signal to investigate the nonlinear characteristics of the system. The bistable behavior arising from magnomechanical nonlinearity exhibits a characteristic magnon switching pattern. This behavior is studied for different values of parameters such as laser power, the coupling strength between magnon and the cavity, modulation amplitude and frequency, and magnomechanical coupling strength. A distinct indication of energy transfer between the mechanical and magnon modes becomes evident while examining the mechanical displacement spectrum within the magnomechanical system. Further, by appropriately adjusting the system parameters, it is observed that the system in its steady state exhibits entanglement dynamics. The results of the entanglement indicate that the suggested system could find application in a quantum communication platform. These findings imply that this system holds potential for applications in highly responsive magnon switches and magnon sensors.