We consider photonic tunnelling through evanescent regions and obtain general analytic expressions for the transit (phase) time $τ$ (in the opaque barrier limit) in order to study the recently proposed ``universality'' property according to which $τ$ is given by the reciprocal of the photon frequency. We consider different physical phenomena (corresponding to performed experiments) and show that such a property is only an approximation. In particular we find that the ``correction'' factor is a constant term for total internal reflection and quarter-wave photonic bandgap, while it is frequency-dependent in the case of undersized waveguide and distributed Bragg reflector. The comparison of our predictions with the experimental results shows quite a good agreement with observations and reveals the range of applicability of the approximated ``universality'' property.
The time behaviour of microwaves undergoing partial reflection by photonic barriers was measured in the time and in the frequency domain. It was observed that unlike the duration of partial reflection by dielectric layers, the measured reflection duration of barriers is independent of their length. The experimental results point to a nonlocal behaviour of evanescent modes at least over a distance of some ten wavelengths. Evanescent modes correspond to photonic tunnelling in quantum mechanics.
We suggest a near deterministic compact model of a photonic CNOT gate based on a quantum dot trapped in a double sided optical microcavity and a universal cloner. Our design surpasses the cloner optimal limit of 5/6 and we show that it provides fidelity around 91 % in the weak coupling regime.
Photonic processors are pivotal for both quantum and classical information processing tasks using light. In particular, linear optical quantum information processing requires both largescale and low-loss programmable photonic processors. In this paper, we report the demonstration of the largest universal quantum photonic processor to date: a low-loss, 12-mode fully tunable linear interferometer with all-to-all coupling based on stoichiometric silicon nitride waveguides.
Scattering thresholds and their associated spectral square root branch points are ubiquitous in photonics. In this Letter, we show that the scattering matrix has a simple universal behavior near scattering thresholds. We use unitarity, reciprocity, and time-reversal symmetry to construct a two-parameter model for a two-port scattering matrix near a threshold. We demonstrate this universal behavior in three different optical systems, namely a photonic crystal slab, a planar dielectric interface, and a junction between metallic waveguides of different widths.
We present a photonic integrated circuit architecture for a quantum programmable gate array (QPGA) capable of preparing arbitrary quantum states and operators. The architecture consists of a lattice of phase-modulated Mach-Zehnder interferometers, which perform rotations on path-encoded photonic qubits, and embedded quantum emitters, which use a two-photon scattering process to implement a deterministic controlled-$σ_z$ operation between adjacent qubits. By appropriately setting phase shifts within the lattice, the device can be programmed to implement any quantum circuit without hardware modi…
We study theoretically the propagation of relatively long pulses with ionizing intensities in a hollow-core photonic crystal fiber filled with a Raman-inactive gas. Due to photoionization, previously unknown types of asymmetric self-phase modulation and `universal' modulational instabilities existing in both normal and anomalous dispersion regions appear. We also show that it is possible to spontaneously generate a plasma-induced continuum of blueshifting solitons, opening up new possibilities for pushing supercontinuum generation towards shorter and shorter wavelengths.
This paper demonstrates the operation of a universal RF photonic circuit that consists of a generalized Mach Zehnder Interferometer architecture with its Nx1 combiner replaced by a NxN optical DFT network. The proposed circuit architecture can be used for SSB modulation, frequency up-conversion/down-conversion, frequency multiplication and phase correlated subcarrier generation based on the choice of output ports and dimension (N) of the circuit. An alternative representation of the circuit is also reported with the aim of a systematic demultiplexing. A transfer matrix approach is used to deve…
We introduce photonic architectures for universal quantum computation. The first step is to produce a resource state which is a superposition of the first four Fock states with a probability $\geq 10^{-2}$, an increase by a factor of $10^4$ over standard sequential photon-subtraction techniques. The resource state is produced with near-perfect fidelity from a quantum gadget that uses displaced squeezed vacuum states, interferometers and photon-number resolving detectors. The parameters of this gadget are trained using machine learning algorithms for variational circuits. We discuss in detail v…
Through an extensive series of high-precision numerical computations of the optimal complete photonic band gap (PBG) as a function of dielectric contrast $α$ for a variety of crystal and disordered heterostructures, we reveal striking universal behaviors of the gap sensitivity $\mathcal{S}(α)\equiv dΔ(α)/dα$, the first derivative of the optimal gap-to-midgap ratio $Δ(α)$. In particular, for all our crystal networks, $\mathcal{S}(α)$ takes a universal form that is well approximated by the analytic formula for a one-dimensional quarter-wave stack, $\mathcal{S}_{\text{QWS}}(α)$. Even more surpris…
Universal quantum computation using photonic systems requires gates whose Hamiltonians are of order greater than quadratic in the quadrature operators. We first review previous proposals to implement such gates, where specific non-Gaussian states are used as resources in conjunction with entangling gates such as the continuous-variable versions of C-PHASE and C-NOT gates. We then propose ON states which are superpositions of the vacuum and the $N^{th}$ Fock state, for use as non-Gaussian resource states. We show that ON states can be used to implement the cubic and higher-order quadrature phas…
Universal unitary photonic devices can apply arbitrary unitary transformations to a vector of input modes and provide a promising hardware platform for fast and energy-efficient machine learning using light. We simulate the gradient-based optimization of random unitary matrices on universal photonic devices composed of imperfect tunable interferometers. If device components are initialized uniform-randomly, the locally-interacting nature of the mesh components biases the optimization search space towards banded unitary matrices, limiting convergence to random unitary matrices. We detail a proc…
Self-Configuring Universal Multichannel and Multidimensional Integrated Photonic Processing Engine
The Hong Kong University of Science and Technology (Guangzhou)（香港科技大学（广州））；Guangdong-Macao Joint Laboratory for Modular Chip Design and Testing, The Hong Kong University of Science and Technology (Guangzhou)（模块化芯片设计与测试粤港联合实验室，香港科技大学（广州））；Department of Electrical and Electronic Engineering, The University of Hong Kong（电气电子工程学系，香港大学）
Shanghai Jiao Tong University（上海交通大学）；University of Electronic Science and Technology of China（电子科技大学）；Tianfu Jiangxi Laboratory（天府江西实验室）；Aalto University（阿尔托大学）
Universal free-space photonic circuits for polarized structured light
Università degli Studi di Napoli Federico II（那不勒斯费德里科二世大学）；Università di Pavia（帕维亚大学）；Istituto Nazionale di Fisica Nucleare, Sezione di Pavia（意大利国家核物理研究所帕维亚分部）
Hardware-Efficient Universal Linear Transformations for Optical Modes in the Synthetic Time Dimension
Department of Electrical and Computer Engineering, University of Maryland（马里兰大学电气与计算机工程系）；Institute for Research in Electronics and Applied Physics, and Joint Quantum Institute, University of Maryland（马里兰大学电子与应用物理研究所及联合量子研究所）；James C. Wyant College of Optical Sciences, University of Arizona（亚利桑那大学詹姆斯·C·怀安特光学科学学院）
Universality and anisotropy of the Photonic Urbach Tail
Instituto de Ciencia de Materiales de Madrid (ICMM), Consejo Superior de Investigaciones Científicas (CSIC)（马德里材料科学研究所，西班牙国家研究委员会）；University of Delaware（特拉华大学）
Visible wavelengths of light control the quantum matter of atoms and molecules and are foundational for quantum technologies, including computers, sensors, and clocks. The development of visible integrated photonics opens the possibility for scalable circuits with complex functionalities, advancing both the scientific and technological frontiers. We experimentally demonstrate an inverse design approach based on superposition of guided-mode sources, allowing the generation and full control of free-space radiation directly from within a single 150 nm layer Ta2O5, showing low loss across visible …
Universal multiport interferometers, which can be programmed to implement any linear transformation between multiple channels, are emerging as a powerful tool for both classical and quantum photonics. These interferometers are typically composed of a regular mesh of beam splitters and phase shifters, allowing for straightforward fabrication using integrated photonic architectures and ready scalability. The current, standard design for universal multiport interferometers is based on work by Reck et al (Phys. Rev. Lett. 73, 58, 1994). We demonstrate a new design for universal multiport interfero…
Resonance is instrumental in modern optics and photonics for novel phenomena such as cavity quantum electrodynamics and electric-field-induced transparency. While one can use numerical simulations to sweep geometric and material parameters of optical structures, these simulations usually require considerably long calculation time (spanning from several hours to several weeks) and substantial computational resources. Such requirements significantly limit their applicability in understanding and inverse designing structures with desired resonance performances. Recently, the introduction of artif…
Universal Neural Network Based Calibration and Control of Programmable Classical and Quantum Photonic Integrated Processors
Centre de Nanosciences et de Nanotechnologies, CNRS, Université Paris-Saclay（纳米科学与纳米技术研究中心，法国国家科学研究中心，巴黎萨克雷大学）；Centre for Nanophotonics, Department of Physics, Engineering Physics and Astronomy, Queen’s University（量子大学纳米光子学中心）；IPronics Programmable Photonics S.L（IPronics可编程光子有限公司）；Photonics Research Lab, iTEAM, Universitat Politècnica de València（瓦伦西亚理工大学iTEAM研究所光子研究实验室）
As shown in the early 1960s, the gain in stimulated Raman scattering (SRS) is drastically suppressed when the rate of creation of phonons (via pump-to-Stokes conversion) is exactly balanced by the rate of phonon annihilation (via pump-to-anti-Stokes conversion). This occurs when the phonon coherence waves synchronized vibrations of a large population of molecules have identical propagation constants for both processes, i.e., they are phase-velocity matched. As recently demonstrated, hydrogen-filled photonic crystal fiber pumped in the vicinity of its zero dispersion wavelength provides an idea…
Optical microresonators are of paramount importance in photonic circuits requiring fine spectral filtering or resonant light recirculation. Key performance metrics improve with increasing resonance quality factor (Q) across all applications. The performance of silicon photonic circuits is often hampered by the low-quality factor of planar silicon microresonators, typically of Q~10^4-10^5. On the other hand, bulk whispering gallery mode resonators provide a wide range of materials with intriguing optical properties and exceptionally high resonant quality factors Q>10^7. However, the efficient c…
While universal quantum computers ideally solve problems such as factoring integers exponentially more efficiently than classical machines, the formidable challenges in building such devices motivate the demonstration of simpler, problem-specific algorithms that still promise a quantum speedup. We construct a quantum boson sampling machine (QBSM) to sample the output distribution resulting from the nonclassical interference of photons in an integrated photonic circuit, a problem thought to be exponentially hard to solve classically. Unlike universal quantum computation, boson sampling merely r…
Delivering on the revolutionary promise of a universal quantum computer will require processors with millions of quantum bits (qubits). In superconducting quantum processors, each qubit is individually addressed with microwave signal lines that connect room temperature electronics to the cryogenic environment of the quantum circuit. The complexity and heat load associated with the multiple coaxial lines per qubit limits the possible size of a processor to a few thousand qubits. Here we introduce a photonic link employing an optical fiber to guide modulated laser light from room temperature to …
We use one photon to simulate an n-qubit quantum system for the first time. We propose a new scheme to realize universal quantum computation in polynomial time O(n^5). A generating set of gates can be realized with high accuracy in the lab. We conclude that photonic quantum computation is one of the promising approaches to universal quantum computation.
Integrated robust universal linear optics based on white-boxed multi-plane light conversion
University of Science and Technology of China（中国科学技术大学）；Anhui Province Key Laboratory of Quantum Network（安徽省量子通信网络重点实验室）；Hefei National Laboratory（合肥国家实验室）；Hefei Guizhen Chip Technologies Co., Ltd.（合肥贵阵芯片技术有限公司）
Photonics-GCCE: group collaborative-competitive evolution multi-agent framework for universal and autonomous optical design
Institute of Precision Optical Engineering, School of Physics Science and Engineering, Tongji University（同济大学物理科学与工程学院精密光学工程研究所）；MOE Key Laboratory of Advanced Micro-Structured Materials（教育部先进微结构材料重点实验室）；Shanghai Frontiers Science Center of Digital Optics（上海数字光学前沿科学中心）；Shanghai Professional Technical Service Platform for Full-Spectrum and High-Performance Optical Thin Film Devices and Applications（上海市全谱高性能光学薄膜器件及应用专业技术服务平台）；Tsinghua Shenzhen International Graduate School, Tsinghua University（清华大学深圳国际研究生院）；College of Information Science and Electronic Engineering and ZJU-Hangzhou Global Scientific and Technological Innovation Center, Zhejiang University（浙江大学信息与电子工程学院及浙大杭州全球科创中心）；Department of Electronic Engineering, Tsinghua University（清华大学电子工程系）；Laboratory of Wave Engineering, Department of Electrical Engineering, EPFL（瑞士联邦理工学院电气工程系波工程实验室）；Department of Electrical and Computer Engineering, National University of Singapore（新加坡国立大学电气与计算机工程系）
Universal Design Path for Optomechanical Crystals and One-dimensional Photonic Crystals
Technical University of Munich（慕尼黑工业大学）；Munich Center for Quantum Science and Technology (MCQST)（慕尼黑量子科学与技术中心）；Luxembourg Institute of Science and Technology (LIST)（卢森堡科学技术研究所）；TUM Center for Quantum Engineering (ZQE)（慕尼黑工业大学量子工程中心）
