We apply the idea of giant slow wave resonance associated with a degenerate photonic band edge to gain enhancement of active media. This approach allows to dramatically reduce the size of slow wave resonator while improving its performance as gain enhancer for light amplification and lasing. It also allows to reduce the lasing threshold of the slow wave optical resonator by at least an order of magnitude.
Surface plasmon polaritons (SPPs) lasing requires population inversion, it is inefficient and possesses poor spectral properties. We develop an inversion-less concept for a quantum plasmonic waveguide that exploits unidirectional superradiant SPP emission of radiation to produce intense coherent surface plasmon beams. Our scheme includes a resonantly driven cold atomic medium in a lossless dielectric situated above an ultra-low loss negative index metamaterial~(NIMM) layer. We propose generating unidirectional superradiant radiation of the plasmonic field within an atomic medium and a NIMM lay…
We report on the observation of backward lasing at 391.4 nm of nitrogen ions pumped by linearly polarized intense femtosecond pulses at 800 nm. The strongly enhanced spectral intensity at 391.4 nm, as well as the amplification of an externally injected backward seeding pulse, confirm that the backward 391.4 nm signal is due to optical amplification in the gas plasma. Compared to the forward emission at 391.4 nm, the optimal backward emission is achieved at a lower gas pressure around 10 mbar, which is due to asymmetry of the backward and forward directions rooted in the traveling excitation ge…
In standard lasers, light amplification requires population inversion between an upper and a lower state to break the reciprocity between absorption and stimulated emission. However, in a medium prepared in a specific superposition state, quantum interference may fully suppress absorption while leaving stimulated emission intact, opening the possibility of lasing without inversion. Here we show that lasing without inversion arises naturally during propagation of intense femtosecond laser pulses in air. It is triggered by the combination of molecular ionization and molecular alignment, both una…
The simultaneous existence of coherent perfect absorption (CPA) and lasing is one of the most intriguing features of non-Hermitian photonics. However, the link between CPA lasing and PT symmetry breaking at the exceptional point (EP) needs clarification. In this paper, we study the manifestations of the CPA-laser effect in a PT-symmetric multilayer loss-gain structure using both the transfer-matrix method and numerical simulations of the Maxwell-Bloch equations. We show that the maximal contrast between absorption and amplification at different phase relations between the input waves is reache…
We present an ultrafast all-optical gated amplifier, or transistor, consisting of a forest of ZnO nanowire lasers. A gate light pulse creates a dense electron-hole plasma and excites laser action inside the nanowires. Source light traversing the nanolaser forest is amplified, partly as it is guided through the nanowires, and partly as it propagates diffusively through the forest. We have measured transmission increases at the drain up to a factor 34 for 385-nm light. Time-resolved amplification measurements show that the lasing is rapidly self-quenching, yielding pulse responses as short as 1.…
Yellow whispering-gallery-mode lasing from amorphous fluoride microspheres
ENSSAT, UMR 6082-CNRS-Institut FOTON, Université de Rennes（雷恩大学）；Centre de Recherche sur les Ions, les Matériaux et la Photonique (CIMAP), UMR 6252 CEA-CNRS- ENSICAEN, Université de Caen Normandie（卡昂诺曼底大学）
Parity-Time (PT) symmetric wave devices, which exploit balanced interactions between material gain and loss, exhibit extraordinary properties, including lasing and flux-conserving scattering processes. In a seemingly different research field, periodically driven systems, also known as time-Floquet systems, have been widely studied as a relevant platform for reconfigurable active wave control and manipulation. In this article, we explore the connection between PT-symmetry and parametric time-Floquet systems. Instead of relying on material gain, we use parametric amplification by considering a t…
Stimulated Brillouin scattering (SBS) offers among the highest nonlinear gains in solid materials and has demonstrated advanced photonics functionalities in waveguides. The large compressibility of gases suggests that SBS may gain in efficiency with respect to condensed materials. Here, by using a gas-filled hollow-core fibre at high pressure, we achieve a strong Brillouin amplification per unit length, exceeding by 6 times the gain observed in fibres with a solid silica core. This large amplification benefits from a higher molecular density and a lower acoustic attenuation at higher pressure,…
Topological Lasing from Thouless Pumping in Bilayer Photonic Crystal
Donostia International Physics Center（圣塞巴斯蒂安国际物理中心）；Chemistry Faculty (UPV/EHU)（巴斯克大学化学学院）；Brown University（布朗大学）；Institute for Basic Science (IBS)（韩国基础科学研究院）；Universität Siegen（锡根大学）；Ecole Centrale de Lyon（里昂中央理工学院）；INSA Lyon（里昂国立应用科学学院）；Université Claude Bernard Lyon 1（里昂第一大学）；CPE Lyon（里昂国家高等化工、物理、生物学院）；CNRS（法国国家科学研究中心）；IKERBASQUE, Basque Foundation for Science（伊克尔巴斯科奎，巴斯克科学基金会）
Light can be used to modify and control properties of media, as in the case of electromagnetically induced transparency or, more recently, for the generation of slow light or bright coherent XUV and X-ray radiation. Particularly unusual states of matter can be created by light fields with strengths comparable to the Coulomb field that binds valence electrons in atoms, leading to nearly-free electrons oscillating in the laser field and yet still loosely bound to the core [1,2]. These are known as Kramers-Henneberger states [3], a specific example of laser-dressed states [2]. Here, we demonstrat…
Demonstration of High-Gain Harmonic Lasing in a Terahertz Free-Electron Laser
Shanghai Advanced Research Institute, Chinese Academy of Sciences（中国科学院上海高等研究院）；Zhangjiang Laboratory（张江实验室）；University of Chinese Academy of Sciences（中国科学院大学）
Integrated ytterbium gain for visible-near-infrared photonics
John A. Paulson School of Engineering and Applied Sciences, Harvard University（哈佛大学生物工程与应用科学学院）；Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology（麻省理工学院电气与计算机科学系）；Electrical, Computer and Energy Engineering, University of Colorado, Boulder（科罗拉多大学博尔德分校电气、计算机和能源工程系）；Chi3 Optics LLC（Chi3光学有限责任公司）；Octave Photonics（Octave光子学公司）；Time and Frequency Division, National Institute of Standards and Technology（美国国家标准与技术研究院时间与频率司）；Department of Physics, University of Colorado Boulder（科罗拉多大学博尔德分校物理系）
Motivated by recent experiments on the generation of coherent light in engineered hybrid quantum systems, we investigate gain in a microwave photonic cavity coupled to quantum dot structures, and develop concrete directions for achieving a giant amplification in photon transmission. We propose two architectures for scaling up the electronic gain medium: (i) $N$ double quantum dot systems (N-DQD), (ii) $M$ quantum dots arranged in series akin to a quantum cascade laser setup. In both setups, the fermionic reservoirs are voltage biased, and the quantum dots are coupled to a single-mode cavity. O…
Pb-chalcogenide colloidal quantum dots (CQDs) are attractive materials to be used as tuneable laser media across the infrared spectrum. However, excessive nonradiative Auger recombination due to the presence of trap states outcompetes light amplification by rapidly annihilating the exciton population, leading to high gain thresholds. Here, we employ a binary blend of CQDs and ZnO nanocrystals in order to passivate the in-gap trap states of PbS-CQD gain medium. Using transient absorption, we measure a five-fold increase in Auger lifetime demonstrating the suppression of trap-assisted Auger reco…
The extraordinary concept of weak value amplification and a number of other seemingly counter-intuitive wave phenomena are manifestations of fine interference effects. Taking example of one such intriguing wave interference phenomenon, namely, optical Fano resonance, we show that weak value amplification naturally arises in such scenario due to near destructive spectral interference between a continuum mode and a narrow resonance mode which mimics the corresponding near destructive interference between the eigenstates of the measuring observable as a consequence of nearly mutually orthogonal p…
Time has emerged as a new degree of freedom for metamaterials, promising new pathways in wave control. However, electromagnetism suffers from limitations in the modulation speed of material parameters. Here we argue that these limitations can be circumvented by introducing a traveling-wave refractive index modulation, with the same phase velocity of the waves. We show how the concept of "luminal grating" can yield giant nonreciprocity, achieve efficient one-way amplification, pulse compression and frequency up-conversion, proposing a realistic implementation in double-layer graphene.
Giant critical response in a driven-dissipative quantum gas
Blackett Laboratory, Imperial College London（帝国理工学院布莱克特实验室）；Department of Physics, Indian Institute of Technology, Bombay（印度孟买理工学院物理系）；Mode Labs Ltd.（Mode Labs有限公司）；EPSRC National Centre for III-V Technologies, University of Sheffield（谢菲尔德大学EPSRC第三至第五族技术国家中心）
