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Theoretical investigation of the transient regime of electromagnetically induced transparency in spherical quantum dot with on-center hydrogen impurity
摘要： The transient evolution of the susceptibility of the spherical quantum dot with an on-center hydrogen impurity, interacting with the continuous wave lasers, with respect to the probe field is studied numerically and analytically by solving optical Bloch equations. The influence of the control Rabi frequency, dephasing rates and laser detunings is discussed. The damped oscillatory behaviour is observed, as well as the amplification of the probe laser light before the stationary regime of the electromagnetically induced transparency is achieved.
关键词： Quantum dot,Hydrogenic impurity,Electromagnetically induced transparency,Transient regime
更新于2025-09-23 15:19:57
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The dispersion behaviors of the tripod-type four-level cylindrical quantum dot under phenomenon of electromagnetically induced transparency
摘要： In this paper, linear and 3rd-order nonlinear group velocities of the probe laser field are investigated in a tripod-type four-level cylindrical quantum dot (TTFLCQD) with parabolic potential in electromagnetically induced transparency. The control lasers at z-polarization are applied to the system and the results are investigated. Also, linear and 3rd-order nonlinear group velocities in z-polarization are compared. The effects of parameters of TTFLCQD and control lasers on linear and 3rd-order nonlinear group velocities are explored. Finally, the results are discussed. The linear and 3rd-order nonlinear group velocities are compared at z-polarization. Furthermore, the effects of parameters of TTFLCQD and control lasers on linear and 3rd-order nonlinear group velocities are explored. Finally, the results are discussed. The linear and 3rd-order nonlinear group velocities are compared at z-polarization. Furthermore, the effects of parameters of TTFLCQD and control lasers on linear and 3rd-order nonlinear group velocities are explored. Finally, the results are discussed.
关键词： Electromagnetically induced transparency,Tripod-type four-level cylindrical quantum dot,Nonlinear group velocity,Linear group velocity,Slow light
更新于2025-09-23 15:19:57
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Study of radiation damage and possible upgrade of the CMS ECAL Laser Monitoring system
摘要： The Electromagnetic Calorimeter (ECAL), one of the main subsystems of the CMS detector, measures the energies of electrons and photons. The ECAL consists of 75848 lead tungstate (PbWO4) crystals. The transparency of crystals is affected by irradiation, and the laser monitoring system is designed to measure the transparency changes for each ECAL crystal over time. In the future, the High-Luminosity LHC upgrade will increase the integrated luminosuty of the LHC and lead to higher radiation damage in all components of the CMS detector. In this work we report the proposed upgrade for the laser monitoring system and the results of computing crystal transparencies based on Run 2 data.
关键词： Laser Monitoring system,radiation damage,crystal transparency,High-Luminosity LHC,CMS ECAL
更新于2025-09-23 15:19:57
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Thermoplasmonica??Activated Hydrogel Based Dynamic Light Attenuator
摘要： This work describes the morphological, optical, and thermo-optical properties of a temperature-sensitive hydrogel poly(N-isopropylacrylamide-co-N-isopropylmethacrylamide) [P(NIPAm-co-NIPMAm]) film containing a specific amount of gold nanorods (GNRs). The light-induced thermoplasmonic heating of GNRs is used to control the optical scattering of an initially transparent hydrogel film. A hydrated P(NIPAm-co-NIPMAm) film is optically clear at room temperature. When heated to temperatures over 37 °C via light irradiation with a resonant source (λ = 810 nm) to the GNRs, a reversible phase transition from a swollen hydrated state to a shrunken dehydrated state occurs. This phenomenon causes a drastic and reversible change in the optical transparency from a clear to an opaque state. A significant red shift (≈30 nm) of the longitudinal band can also be seen due to an increased average refractive index surrounding the GNRs. This change is in agreement with an ad hoc theoretical model which uses a modified Gans theory for ellipsoidal nanoparticles. Morphological analysis of the composite film shows the presence of well-isolated and randomly dispersed GNRs. Thermo-optical experiments demonstrate an all-optically controlled light attenuator (65% contrast ratio) which can be easily integrated in several modern optical applications such as smart windows and light-responsive optical attenuators.
关键词： gold nanorods,active plasmonics,optical attenuators,polymers,optical transparency,hydrogels,plasmonic nanoparticles
更新于2025-09-23 15:19:57
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Review on plasmon induced transparency based on metal-dielectric-metal waveguides; ??o?o? MDM ?3￠?ˉ?????-??|??-????èˉ±?ˉ?é??????????????è?°;
摘要： Plasmon induced transparency (PIT) in the transparent window provides new insights into the design of optical filters, switches and storage, and integrated optics. The slow light effect makes PIT applicable to both sensors and slow light devices. Besides, PIT can overcome the diffraction limit of light, which makes it possible to manipulate light on a half-wavelength scale and brings good news to the miniaturization of optical devices. In this paper, we first summarize the researches of PIT phenomenon based on metal-dielectric-metal (MDM) waveguide systems and analyze the physical mechanisms of PIT including bright-dark mode interactions and phase-coupling-induced transparency. Then, we review the applications of PIT in optical sensing, optical filtering, optical switching, slow light devices and optical logic devices. At last, we outline important challenges that need to be addressed, provide corresponding solutions and predict important directions for future research in this area.
关键词： slow-light effect,plasmon induced transparency (PIT),metal-dielectric-metal (MDM) waveguide,optical logic devices
更新于2025-09-23 15:19:57
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Wide-range line shape control of Fano-like resonances in all-dielectric multilayer structures based on enhanced light absorption in photochromic waveguide layers
摘要： We have succeeded in controlling the line shape of Fano-like resonances in all-dielectric multilayer structures in a wide range by UV light irradiation. Multilayer structures consisting of a waveguide layer supporting a half-leaky guided mode, a spacer layer, and another waveguide layer supporting a planar waveguide mode are known to exhibit Fano-like line shapes in attenuated total reflection spectra due to coupling between the half-leaky guided mode and the planar waveguide mode. Using a photochromic layer, i.e., a layer doped with spiropyran molecules, as one of the waveguide layers, we controlled the amount of light absorption in the waveguide layer by varying the UV irradiation dose. We demonstrated that the line shape changes dramatically depending on the UV dose, from the electromagnetically induced transparency-like to electromagnetically induced absorption-like line shape (or vice versa) passing through the Fano-like line shape. We also demonstrated that the photochromic response induced by UV irradiation in the Fano-resonant multilayer structure is enhanced by a factor of ～100 relative to that in a single photochromic layer. Our analyses based on electromagnetic calculations suggest that the dramatic line shape change and the enhanced photochromic response are the consequences of enhanced local electric fields inside the photochromic waveguide layer combined with the photoinduced increase in the imaginary part of the dielectric constant.
关键词： electromagnetically induced transparency,all-dielectric multilayer structures,Fano-like resonances,UV light irradiation,electromagnetically induced absorption,photochromic waveguide layers
更新于2025-09-23 15:19:57
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Mode Locking in Lasers due to Self-Induced Transparency: New Theoretical and Experimental Results
摘要： Recent theoretical and experimental results on coherent passive mode locking in lasers due to self-induced transparency are revised. In contrast to traditional laser systems, where passive mode locking occurs due to the effects of incoherent gain and absorption saturation, this regime of mode locking arises due to coherent interaction between light and matter. Theoretical results are presented that demonstrate the possibility of obtaining single-cycle pulses in a laser with a linear cavity of ultrashort length. Results are also presented from what are apparently the first experiments on coherent mode locking due to self-induced transparency in lasers.
关键词： lasers,single-cycle pulses,self-induced transparency,mode locking,coherent interaction
更新于2025-09-23 15:19:57
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Tunable plasmon-induced transparency and slow light in terahertz chipscale semiconductor plasmonic waveguides
摘要： We numerically propose the plasmon-induced transparency (PIT) and slow light effect based on terahertz (THz) chipscale plasmonic semiconductor-insulator-semiconductor (SIS) waveguide system. Via the coupling between two stub resonators, PIT is introduced due to the destructive interference, which can be theoretically described by the transmission-line Method (TLM). Meanwhile, the strong dispersion within the transparent window will lead to the slow light effect. Via tuning the geometric parameters, the profile of PIT as well as group delay line can be arbitrarily tailored. Moreover, active control of both PIT and slow light can be realized by changing the ambient temperature. Especially, by integrating monolayer graphene into the structure, PIT and slow light can also be electrically modulated via applying voltage. This work provides geometrical, thermal and electrical approaches to manipulate THz transmission and group delay in subwavelength scale, and can find potential applications as filters, sensors, modulators and active optical delay lines in THz ultracompact circuits.
关键词： graphene,plasmon-induced transparency,slow light,terahertz,plasmonic waveguide
更新于2025-09-23 15:19:57
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Coupled-mode-induced transparency and attenuation resulting from cross-polarization coupling
摘要： Induced transparency and attenuation effects are observed in the throughput of a single whispering-gallery microresonator due to mode coupling between two coresonant orthogonally polarized whispering-gallery modes of very different quality factors. Intracavity cross-polarization coupling, occurring when either the transverse electric (TE) mode or the transverse magnetic (TM) mode is driven, results in coupled-mode induced transparency or coupled-mode induced attenuation. Coresonance between the TE and TM modes is obtained by strain tuning, and the cross-polarization coupling is produced by polarization rotation due to optical spin-orbit interaction in a slightly asymmetric resonator. The observed behavior enables slow light and fast light, i.e., the delay or advancement of an incident resonant pulse. Experimental results representative of several different types of behavior are presented here. Induced transparency is seen to be accompanied by pulse delay, whereas induced attenuation can involve pulse advancement or delay. The results are analyzed and explained by analytical modeling and by comparison to the output of a more detailed numerical model describing these effects. Delays of up to 170 ns and advancements of up to 14 ns are found. The observed range of cross-polarization coupling strengths (probability of polarization change per round trip), namely, 10?10–10?7, is in agreement with theory.
关键词： slow light,induced transparency,whispering-gallery microresonator,cross-polarization coupling,attenuation,fast light
更新于2025-09-23 15:19:57
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INVESTIGATION ON PLASMON INDUCED TRANSPARENCY AND ITS APPLICATION IN AN MIM TYPECOMPOUND PLASMONIC WAVEGUIDE
摘要： In this paper, the investigation about a metal-insulator-metal (MIM) compound plasmonic waveguide is reported, which possesses the transmission property of plasmon induced transparency (PIT) and exhibits the potential application of refractive index sensing. The waveguide structure consists of an MIM-type bus waveguide, a horizontally placed asymmetric H-type resonator (AHR), and a circular ring resonator (CRR). The AHR is directly coupled with the bus waveguide, while the CRR is directly coupled to the AHR, but is indirectly coupled to the bus waveguide. Due to the destructive interference between two di?erent transmission paths, PIT e?ect can be observed in the transmission spectrum. The ?nite element method (FEM) is used to study the PIT e?ect in detail. The results show that the transmission characteristics can be ?exibly adjusted by changing the geometric parameters of the structure, and the proposed waveguide structure has potential application prospects in the area of temperature and refractive index sensing with higher sensitivity, better ?gure of merit, and in the area of slow light photonic devices.
关键词： plasmon induced transparency,slow light,MIM waveguide,refractive index sensing
更新于2025-09-23 15:19:57