Publications (101)
Pseudo-Hermitian Transition in Degenerate Nonlinear Four-Wave Mixing
Li Ge, Wenjie Wan
We show that degenerate four-wave mixing (FWM) in nonlinear optics can be described by an effective Hamiltonian that is pseudo-Hermitian, which enables a transition between a pseud…
Symmetry-protected zero-mode laser with a tunable spatial profile
Li Ge
We propose to utilize symmetry-protected zero modes of a photonic lattice to realize a single-mode, fixed-frequency, and spatially tunable laser. These properties are the consequen…
Observing complementary Lucas sequences using non-Hermitian zero modes
Li Ge
The Lucas sequences are integers defined by a homogeneous recurrence relation. They include the well-known Fibonacci numbers, which appear abundantly in nature. The complementary L…
Non-Hermitian systems with a real spectrum and selective skin effect
Li Ge
In this work we first show a simple approach to constructing non-Hermitian Hamiltonians with a real spectrum, which are \textit{not} obtained by a non-unitary transformation such a…
Strong Interactions in Multimode Random Lasers
Hakan E. Türeci, Li Ge, Stefan Rotter +1
Unlike conventional lasers, diffusive random lasers (DRLs) have no resonator to trap light and no high-Q resonances to support lasing. Due to this lack of sharp resonances the DRL…
Pump-induced Exceptional Points in Lasers
M. Liertzer, Li Ge, A. Cerjan +3
We demonstrate that the above-threshold behavior of a laser can be strongly affected by exceptional points which are induced by pumping the laser nonuniformly. At these singulariti…
Time-reversal invariant scaling of light propagation in one-dimensional non-Hermitian systems
Jose Hernandez Rivero, Li Ge
Light propagation through a normal medium is determined not only by the real part of the refractive index but also by its imaginary part, which represents optical gain and loss. Th…
Quantum coherence in multipartite systems
Yao Yao, Xing Xiao, Li Ge +1
Within the unified framework of exploiting the relative entropy as a distance measure of quantum correlations, we make explicit the hierarchical structure of quantum coherence, qua…
Theory of the spatial structure of non-linear lasing modes
Hakan E. Türeci, A. Douglas Stone, Li Ge
A self-consistent integral equation is formulated and solved iteratively which determines the steady-state lasing modes of open multi-mode lasers. These modes are naturally decompo…
Supporting Online Material for "Strong Interactions in Multimode Random Lasers"
Hakan E. Türeci, Li Ge, Stefan Rotter +1
This preprint contains the Supporting Online Material for our paper ''Strong Interactions in Multimode Random Lasers'', Science 320, 643 (2008) (also available at: arXiv:0805.4496)…
Pump-Controlled Modal Interactions in Microdisk Lasers
Seng Fatt Liew, Li Ge, Brandon Redding +2
We demonstrate an effective control of nonlinear interactions of lasing modes in a semiconductor microdisk cavity by shaping the pump profile. A target mode is selected at the expe…
Tracking exceptional points above laser threshold
Kaiwen Ji, Qi Zhong, Li Ge +5
Recent studies on non-Hermitian optical systems having exceptional points (EPs) have revealed a host of unique characteristics associated with these singularities, including unidir…
Steady-State Ab Initio Laser Theory for N-level Lasers
Alexander Cerjan, Yidong Chong, Li Ge +1
We show that Steady-state Ab initio Laser Theory (SALT) can be applied to find the stationary multimode lasing properties of an N-level laser. This is achieved by mapping the N-lev…
Non-Hermitian gauged laser arrays with localized excitations: Anomalous threshold and generalized principle of selective pumping
Li Ge, Zihe Gao, Liang Feng
We investigate non-Hermitian skin modes in laser arrays with spatially localized excitation. Intriguingly, we observe an unusual threshold behavior when selectively pumping either…
Unconventional modes in lasers with spatially varying gain and loss
Li Ge, Y. D. Chong, S. Rotter +2
We discuss a class of lasing modes created by a spatially inhomogeneous gain profile. These lasing modes are "extra modes", in addition to, and very different from, conventional la…
Analysis of Dirac exceptional points and their isospectral Hermitian counterparts
Jose H. D. Rivero, Liang Feng, Li Ge
Recently, a Dirac exceptional point (EP) was reported in a non-Hermitian system. Unlike a Dirac point in Hermitian systems, this Dirac EP has coalesced eigenstates in addition to t…
Condensation of Thresholds in Multimode Microlasers
Li Ge, Hui Cao, A. Douglas Stone
We show from ab initio laser theory that by choosing an appropriate spatial pump profile, many different spatial modes of a typical microlaser can be turned on at the same pump ene…
Multiple phase estimation in quantum cloning machines
Yao Yao, Li Ge, Xing Xiao +2
Since the initial discovery of the Wootters-Zurek no-cloning theorem, a wide variety of quantum cloning machines have been proposed aiming at imperfect but optimal cloning of quant…
Pattern Formation and Strong Nonlinear Interactions in Exciton-Polariton Condensates
Li Ge, Ani Nersisyan, Baris Oztop +1
Exciton-polaritons generated by light-induced potentials can spontaneously condense into macroscopic quantum states that display nontrivial spatial and temporal density modulation.…
Constructing the scattering matrix for optical microcavities as a nonlocal boundary value problem
Li Ge
We develop a numerical scheme to construct the scattering () matrix for optical microcavities, including the special cases with parity-time and other non-Hermitian symmetries. T…
Controlling mode competition by tailoring the spatial pump distribution in a laser: A resonance-based approach
Alexander Cerjan, Brandon Redding, Li Ge +3
We introduce a simplified version of the steady-state ab initio laser theory for calculating the effects of mode competition in continuous wave lasers using the passive cavity reso…
Extreme Sensitivity of Output Directionality to Boundary Perturbation in Wavelength-Scale Microcavities
Li Ge, Qinghai Song, Brandon Redding +1
We report a surprising observation that the output directionality from wavelength-scale optical microcavities displays extreme sensitivity to deformations of the cavity shape. A va…
Anomalous transient amplification of waves in non-normal photonic media
Konstantinos G. Makris, Li Ge, Hakan E. Tureci
Dissipation is a ubiquitous phenomenon in dynamical systems encountered in nature because no finite system is fully isolated from its environment. In optical systems, a key challen…
Invertible condition of quantum Fisher information matrix for a mixed qubit
Ping Yue, Li Ge, Qiang Zheng
Estimating multiparamter simultaneously as precise as possible is an important goal of quantum metrolo- gy. As a first step to this end, here we give a condition determining whethe…
Multiple phase estimation for arbitrary pure states under white noise
Yao Yao, Li Ge, Xing Xiao +2
In any realistic quantum metrology scenarios, the ultimate precision in the estimation of parameters is limited not only by the so-called Heisenberg scaling, but also the environme…
Pseudo-chirality: a manifestation of Noether's theorem in non-Hermitian systems
Jose D. H. Rivero, Li Ge
Noether's theorem relates constants of motion to the symmetries of the system. Here we investigate a manifestation of Noether's theorem in non-Hermitian systems, where the inner pr…
Exceptional points and lasing self-termination in photonic molecules
Ramy El-Ganainy, Mercedeh Khajavikhan, Li Ge
We investigate the rich physics of photonic molecule lasers using a non-Hermitian dimer model. We show that several interesting features, predicted recently using a rigorous steady…
Defect states emerging from a non-Hermitian flat band of photonic zero modes
Bingkun Qi, Lingxuan Zhang, Li Ge
We show the existence of a flat band consisting of photonic zero modes in a gain and loss modulated lattice system, as a result of the underlying non-Hermitian particle-hole symmet…
Precise measurement of coupling strength and high temperature quantum effect in a nonlinearly coupled qubit-oscillator system
Li Ge, Nan Zhao
We study the coherence dynamics of a qubit coupled to a harmonic oscillator with both linear and quadratic interactions. As long as the linear coupling strength is much smaller tha…
Nonlinear modal interactions in parity-time () symmetric lasers
Li Ge, Ramy El-Ganainy
Parity-time () symmetric lasers have attracted considerable attention lately due to their promising applications and intriguing properties, such as free spectral range dou…
Direct observation of zero modes in a non-Hermitian nanocavity array
Flore Hentinger, Melissa Hedir, Bruno Garbin +5
Zero modes are symmetry protected ones whose energy eigenvalues have zero real parts. In Hermitian arrays, they arise as a consequence of the sublattice symmetry, implying that the…
Rotation-induced Mode Coupling in Open Wavelength-scale Microcavities
Li Ge, Raktim Sarma, Hui Cao
We study the interplay between rotation and openness for mode coupling in wavelength-scale microcavities. In cavities deformed from a circular disk, the decay rates of a quasi-dege…
Enhancing parameter precision of optimal quantum estimation by direct quantum feedback
Qiang Zheng, Li Ge, Yao Yao +1
Various schemes have been proposed to overcome the drawback of the decoherence on quantum-enhanced parameter estimation. Here we suggest an alternative method, quantum feedback, to…
Antisymmetric PT-photonic structures with balanced positive and negative index materials
Li Ge, H. E. Tureci
We propose a new class of synthetic optical materials in which the refractive index satisfies $n(-\bx)=-n^*(\bx)$. We term such systems antisymmetric parity-time (APT) structures.…
Robust zero modes in non-Hermitian systems without global symmetries
Jose D. H. Rivero, Courtney Fleming, Bingkun Qi +2
We present an approach to achieve zero modes in lattice models that do not rely on any symmetry or topology of the bulk, which are robust against disorder in the bulk of any type a…
Enhancement of Laser Power Efficiency by Control of Spatial Hole Burning Interactions
Li Ge, Omer Malik, Hakan E. Tureci
The laser is an out-of-equilibrium nonlinear wave system where the interplay of the cavity geometry and nonlinear wave interactions, mediated by the gain medium, determines the sel…
Quantitative Verification of Ab Initio Self-consistent Laser Theory
Li Ge, Robert J. Tandy, A. Douglas Stone +1
We generalize and test the recent "ab initio" self-consistent (AISC) time-independent semiclassical laser theory. This self-consistent formalism generates all the stationary lasing…
Effective size of a parity-time symmetric dimer
Li Ge
Parity-time (PT) symmetric dimers were introduced to highlight the unusual properties of non-Hermitian systems that are invariant after a combined parity and time reversal operatio…
Rotation-induced Asymmetry of Far-field Emission from Optical Microcavities
Li Ge, Raktim Sarma, Hui Cao
We study rotation-induced asymmetry of far-field emission from optical microcavities, based on which a new scheme of rotation detection may be developed. It is free from the "dead…
Detecting and Understanding the Difference between Natural Mediation Effects and Their Randomized Interventional Analogues
Ang Yu, Li Ge, Felix Elwert
In causal mediation analysis, the natural direct and indirect effects (natural effects) are nonparametrically unidentifiable in the presence of treatment-induced confounding, which…
Stable Switching among High-Order Modes in Polariton Condensates
Yongbao Sun, Yoseob Yoon, Saeed Khan +6
We report multistate optical switching among high-order bouncing-ball modes ("ripples") and whispering-gallerying modes ("petals") of exciton-polariton condensates in a laser-gener…
Comment on "Unified view of quantum correlations and quantum coherence"
Yao Yao, Li Ge, Mo Li
We show that contrary to what it is claimed in Phys. Rev. A \textbf{94}, 022329 (2016), in general the local projective measurement that induces maximal coherence loss is \textit{n…
Directional waveguide coupling from a wavelength-scale deformed microdisk laser
Brandon Redding, Li Ge, Glenn S. Solomon +1
We demonstrate uni-directional evanescent coupling of lasing emission from a wavelength-scale deformed microdisk to a waveguide. This is attributed to the Goos-Hänchen shift and F…
Linear localization of zero modes in weakly coupled non-Hermitian reservoirs
Bingkun Qi, Li Ge
Topological and symmetry-protected non-Hermitian zero modes have attracted considerable interest in the past few years. Here we reveal that they can exhibit an unusual behavior whe…
Chiral-reversing vortex radiation from a single emitter by eigenstates phase locking
Xing-Yuan Wang, Hua-Zhou Chen, Suo Wang +3
The radiation of an emitter does not depend only on its intrinsic properties but also on the surrounding photonic environment, the notion of which is essential in the developments…
Gain-tunable optomechanical cooling in a laser cavity
Li Ge, Sanli Faez, Florian Marquardt +1
We study the optical cooling of the resonator mirror in a cavity-optomechanical system that contains an optical gain medium. We find that the optical damping rate is vanishingly sm…
Conservation relations and anisotropic transmission resonances in one-dimensional PT-symmetric photonic heterostructures
Li Ge, Y. D. Chong, A. D. Stone
We analyze the optical properties of one-dimensional (1D) PT-symmetric structures of arbitrary complexity. These structures violate normal unitarity (photon flux conservation) but…
Dual-color Coherent Perfect Absorber
Boyi Xue, Jintian Lin, Jiankun Hou +6
Perfect absorption of light critically affects light-matter interaction for various applications. Coherent perfect absorbers (CPA) gain the unique capability of controlling light w…
Optical Reciprocity Induced Symmetry of the Scattering Eigenstates in Non--Symmetric Heterostructures
Li Ge, Liang Feng
The scattering matrix obeys the unitary relation in a Hermitian system and the symmetry property in a Parity-Time () sym…
Enhanced Frequency Conversion in Parity-Time Symmetry Line
Jiankun Hou, Jiefu Zhu, Ruixin Ma +9
Non-Hermitian degeneracies reveal intriguing and non-trivial behaviors in open physical systems. Examples like Parity-Time (PT) symmetry breaking, topological encircling chirality,…
Maximal coherence in generic basis
Yao Yao, G. H. Dong, Li Ge +2
Since quantum coherence is an undoubted characteristic trait of quantum physics, the quantification and application of quantum coherence has been one of the long-standing central t…
Ground states of a mixture of two species of spin-1 Bose gases with interspecies spin exchange in a magnetic field
Yu Shi, Li Ge
We consider a mixture of two species of spin-1 atoms with both interspecies and intraspecies spin exchanges in a weak magnetic field. Under the usual single mode approximation, it…
Anomalous minimum and scaling behavior of localization length near an isolated flat band
Li Ge
Using one-dimensional tight-binding lattices and an analytical expression based on the Green's matrix, we show that anomalous minimum of the localization length near an isolated fl…
Local chirality of optical waves in ultrasmall resonators
Brandon Redding, Li Ge, Qinghai Song +3
The local chiral symmetry between clockwise (CW) and counter-clockwise (CCW) propagating light in a deformed microcavity can be broken by wave optics effects, which become signific…
Experimental demonstration of spontaneous chirality in a nonlinear microresonator
Qi-Tao Cao, He-Ming Wang, Chun-Hua Dong +6
Chirality is an important concept that describes the asymmetry property of a system, which usually emerges spontaneously due to mirror symmetry breaking. Such spontaneous chirality…
Three-dimensional quantum phase diagram of the exact ground states of a mixture of two species of spin-1 Bose gases with interspecies spin exchange
Yu Shi, Li Ge
We find nearly all the exact ground states of a mixture of two species of spin-1 atoms with both interspecies and intraspecies spin exchanges in absence of a magnetic field. The qu…
Twisted light from topological chiral exceptional points in a nanolaser array
Kaiwen Ji, Melissa Hedir, Qi Zhong +3
We propose and experimentally demonstrate an orbital angular momentum (OAM) nanolaser array arranged in a ring geometry on an InP-based photonic crystal membrane. The device realiz…
Robust Wideband Channel Estimation for mmWave Massive MIMO Systems With Beam Squint
Li Ge, Lin Chen, Xue Jiang +3
This paper investigates the robust wideband channel estimation problem in the millimeter-wave (mmWave) massive multiple-input multiple-output (MIMO) systems. In such a scenario, th…
The damping and diffusion of atoms moving in the background electromagnetic environment
Li Ge
The interaction between an atom and the quantized electromagnetic field depends on the position of the atom. Then the atom experiences a force which is the minus gradient of this i…
Field theory of low energy excitations of a mixture of two species of pseudospin-1/2 Bose gases with interspecies spin-exchange
Li Ge, Yu Shi
We develop a low energy effective field theory of a mixture of two species of pseudospin-1/2 atoms with interspecies spin-exchange, in addition to density-density interaction. This…
Modes of Random Lasers
Jonathan Andreasen, Ara Asatryan, Lc Botten +8
In conventional lasers, the optical cavity that confines the photons also determines essential characteristics of the lasing modes such as wavelength, emission pattern, ... In rand…
PT-symmetry breaking and laser-absorber modes in optical scattering systems
Y. D. Chong, Li Ge, A. Douglas Stone
Using a scattering matrix formalism, we derive the general scattering properties of optical structures that are symmetric under a combination of parity and time-reversal (PT). We d…
Non-Hermitian engineering of single mode two dimensional laser arrays
Mohammad H. Teimourpour, Li Ge, Demetrios N. Christodoulides +1
A new scheme for building two dimensional laser arrays that operate in the single supermode regime is proposed. This is done by introducing an optical coupling between the laser ar…
Origin of robust exceptional points: a restricted bulk zero mode
Jose D. H. Rivero, Li Ge
Recently a type of robust exceptional points was found that is insensitive to the coupling disorder in the bulk. Here we show that a disparity emerges when the number of coupled ca…
Non-Hermitian gauged reciprocity and symmetry
Jiecheng Lyu, Zihe Gao, Liang Feng +1
The Lorentz reciprocity is a fundamental property in electromagnetism and well known to break down due to an external magnetic field. With a fictitious or imaginary vector potentia…
Effects of Spatially Nonuniform Gain on Lasing Modes in Weakly Scattering Random Systems
Jonathan Andreasen, Christian Vanneste, Li Ge +1
A study on the effects of optical gain nonuniformly distributed in one-dimensional random systems is presented. It is demonstrated numerically that even without gain saturation and…
Tight Bounds for Gaussian Mean Estimation under Personalized Differential Privacy
Wei Dong, Li Ge
We study mean estimation for Gaussian distributions under \textit{personalized differential privacy} (PDP), where each record has its own privacy budget. PDP is commonly considered…
Active control of emission directionality of semiconductor microdisk lasers
Seng Fatt Liew, Brandon Redding, Li Ge +2
We demonstrate lasing mode selection in nearly circular semiconductor microdisks by shaping the spatial profile of optical pump. Despite of strong mode overlap, adaptive pumping su…
Subwavelength Photorefractive Grating in a Thin-Film Lithium Niobate Microcavity
Jiankun Hou, Jiefu Zhu, Ruixin Ma +9
Subwavelength gratings play a fundamental and pivotal role in numerous science and applications for wave manipulation, exhibiting distinctive features such as filtering, phase mani…
Imaginary gauge transformation in momentum space and Dirac exceptional point
Jose H. D. Rivero, Liang Feng, Li Ge
An imaginary gauge transformation is at the core of the non-Hermitian skin effect. Here we show that such a transformation can be performed in momentum space as well, which reveals…
ROI-Guided Point Cloud Geometry Compression Towards Human and Machine Vision
Xie Liang, Gao Wei, Zhenghui Ming +1
Point cloud data is pivotal in applications like autonomous driving, virtual reality, and robotics. However, its substantial volume poses significant challenges in storage and tran…
Quantum fisher information in noninertial frames
Yao Yao, Xing Xiao, Li Ge +2
We investigate the performance of quantum fisher information under the Unruh-Hawking effect, where one of the observers (eg, Rob) is uniformly accelerated with respect to other par…
Ab initio self-consistent laser theory and random lasers
Hakan E. Türeci, A. Douglas Stone, Li Ge +2
We review our recent work leading to steady-state solutions of the semiclassical (Maxwell-Bloch) equations of a laser. These are coupled non-linear partial differential equations i…
Exact Tensor Completion Powered by Slim Transforms
Li Ge, Lin Chen, Yudong Chen +1
In this work, a tensor completion problem is studied, which aims to perfectly recover the tensor from partial observations. The existing theoretical guarantee requires the involved…
Inverse Vernier Effects in Coupled Lasers
Li Ge, Hakan E. Tureci
In this report we study the Vernier effect in coupled laser systems consisting of two cavities. We show that depending on the nature of their coupling, not only can the "supermodes…
Non-Hermitian lattices with a flat band and polynomial power increase
Li Ge
In this work we first discuss systematically three general approaches to construct a non-Hermitian flat band, defined by its dispersionless real part. They resort to, respectively,…
Cyclic ladder operators and hidden Weyl-Heisenberg structure in a Floquet system
Tianao Wu, Li Ge
Ladder operators, found in the quantum harmonic oscillator and other quantized systems, provide an elegant approach to solving or understanding otherwise intricate physics problems…
Parity-Time Symmetry Breaking beyond One Dimension: The Role of Degeneracy
Li Ge, A. Douglas Stone
We consider the role of degeneracy in Parity-Time (PT) symmetry breaking for non-hermitian wave equations beyond one dimension. We show that if the spectrum is degenerate in the ab…
Synthetic parity-time symmetry breaking in a single microcavity
Fangxing Zhang, Yaming Feng, Li Ge +1
Non-Hermitian systems based on parity-time (PT) symmetry reveal rich physics beyond the Hermitian regime. So far, realizations of PT-symmetric systems have been limited to the spat…
Cooling of the rotation of a nanodiamond via the interaction with the electron spin of the contained NV-center
Li Ge, Nan Zhao
We propose a way to cool the rotation of a nanodiamond, which contains a NV-center and is levitated by an optical tweezer. Following the rotation of the particle, the NV-center ele…
Interaction-induced mode switching in steady-state microlasers
Li Ge, David Liu, Alexander Cerjan +5
We demonstrate that due to strong modal interactions through cross-gain saturation, the onset of a new lasing mode can switch off an existing mode via a negative power slope. In th…
Mode Selection and Single-mode Lasing by Active Transformation Optics
Li Ge
Using the correspondence between (saturated) nonlinear and (unsaturated) linear dielectric constants, we propose a simple and systematic method to achieve selective excitation of l…
Anomalous Parity-Time Symmetry Transition away from an Exceptional Point
Li Ge
Parity-time (PT) symmetric systems have two distinguished phases, e.g., one with real energy eigenvalues and the other with complex conjugate eigenvalues. To enter one phase from t…
Chiral symmetry in non-Hermitian systems: product rule and Clifford algebra
Jose D. H. Rivero, Li Ge
Chiral symmetry provides the symmetry protection for a large class of topological edge states. It exists in non-Hermitian systems as well, and the same anti-commutation relation be…
Supersymetric laser arrays
Ramy El-Ganainy, Li Ge, Mercedeh Khajavikhan +1
We introduce the concept of supersymmetric laser arrays that consists of a main optical lattice and its superpartner structure, and we investigate the onset of their lasing oscilla…
Coherent Perfect Absorbers: Time-reversed Lasers
Y. D. Chong, Li Ge, Hui Cao +1
We show that an arbitrary body or aggregate can be made perfectly absorbing at discrete frequencies if a precise amount of dissipation is added under specific conditions of coheren…
Sine-Gordon model coupled with a free scalar field emergent in the low-energy phase dynamics of a mixture of pseudospin-1/2 Bose gases with interspecies spin exchange
Li Ge, Yu Shi
Using the approach of low-energy effective field theory, the phase diagram is studied for a mixture of two species of pseudospin-$\1/2$ Bose atoms with interspecies spin-exchange.…
Insight of the Green's function as a defect state in a boundary value problem
Jose D. H. Rivero, Li Ge
A new perspective of the Green's function in a boundary value problem as the only eigenstate in an auxiliary formulation is introduced. In this treatment, the Green's function can…
Correlated spontaneous symmetry breaking induced by zero-point fluctuations in a quantum mixture
Li Ge, Fei Zhou, Yu Shi
We propose a form of spontaneous symmetry breaking driven by zero-point quantum fluctuations. To be specific, we consider the low-energy dynamics of a mixture of two species of spi…
Steady-state Ab Initio Laser Theory: Generalizations and Analytic Results
Li Ge, Y. D. Chong, A. Douglas Stone
We improve the steady-state ab initio laser theory (SALT) of Tureci et al. by expressing its fundamental self-consistent equation in a basis set of threshold constant flux states t…
Scattering in and Symmetric Multimode Waveguides: Generalized Conservation Laws and Spontaneous Symmetry Breaking beyond One Dimension
Li Ge, Konstantinos G. Makris, Demetrios N. Christodoulides +1
We extend the generalize conservation law of light propagating in a one-dimensional -symmetric system, i.e., for the transmittance and the reflec…
Discriminative-Region Attention and Orthogonal-View Generation Model for Vehicle Re-Identification
Huadong Li, Yuefeng Wang, Ying Wei +2
Vehicle re-identification (Re-ID) is urgently demanded to alleviate thepressure caused by the increasingly onerous task of urban traffic management. Multiple challenges hamper the…
Multimode Coupling by Boundary Wave Scattering
Li Ge, Qinghai Song, Brandon Redding +3
We show that coupling among multiple resonances can be conveniently introduced and controlled by boundary wave scattering. We demonstrate this principle in optical microcavities of…
Symmetry, stability, and computation of degenerate lasing modes
David Liu, Bo Zhen, Li Ge +6
We present a general method to obtain the stable lasing solutions for the steady-state ab-initio lasing theory (SALT) for the case of a degenerate symmetric laser in two dimensions…
Breaking of PT-symmetry in bounded and unbounded scattering systems
Philipp Ambichl, Konstantinos G. Makris, Li Ge +3
PT-symmetric scattering systems with balanced gain and loss can undergo a symmetry-breaking transition in which the eigenvalues of the non-unitary scattering matrix change their ph…
Observation of Gain Spiking and Nonlinear Beating of Optical Frequency Comb in a Microcavity
Yuanlin Zheng, Tian Qin, Jianfan Yang +3
Optical frequency combs are crucial for both fundamental science and applications demanding wide frequency spanning and ultra-precision resolutions. Recent advancements of nonlinea…
Parity-time symmetry in a flat band system
Li Ge
In this paper we introduce Parity-Time () symmetric perturbation to a one-dimensional Lieb lattice, which is otherwise -symmetric and has a flat band. In the flat…
Contrasting Spectral Signatures and Sensitivities of CPA-Lasing in a -Symmetric Periodic Structure
Li Ge, Liang Feng
The CPA-laser is a coexisting state of coherent perfect absorption and lasing that was proposed in parity-time () symmetric photonic systems. In this work we show that the…
Skywork R1V: Pioneering Multimodal Reasoning with Chain-of-Thought
Yi Peng, Peiyu Wang, Xiaokun Wang +12
We introduce Skywork R1V, a multimodal reasoning model extending the an R1-series Large language models (LLM) to visual modalities via an efficient multimodal transfer method. Leve…
Optical fluxes in coupled -symmetric photonic structures
Li Ge, Konstantinos G. Makris, Lingxuan Zhang
In this work we first examine transverse and longitudinal fluxes in a -symmetric photonic dimer using a coupled-mode theory. Several surprising understandings are obtained…