- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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Mimicking a hybrid-optomechanical system using an intrinsic quadratic coupling in conventional optomechanical system
摘要： We consider an optical and mechanical mode interacting through both linear and quadratic dispersive couplings in a general cavity-optomechanical set-up. The parity and strength of an intrinsic quadratic optomechanical coupling (QOC) provides an opportunity to control the optomechanical (OM) interaction. We quantify this interaction by studying normal-mode splitting (NMS) as a function of the QOC's strength. The proposed scheme exhibits NMS features equivalent to a hybrid-OM system containing either an optical parametric amplifier or a Kerr medium. Such a system in reality could offer an alternative platform for devising state-of-art quantum devices with requiring no extra degrees-of-freedom as in hybrid-OM systems.
关键词： Cavity-optomechanics,quadratic optomechanical coupling,normal-mode splitting,resolved side-band regime
更新于2025-09-23 15:22:29
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Discoveries and Explorations of Mode Splitting Phenomenon in Lossy Dielectric Waveguide
摘要： We discovered that a specific transmission mode in the fiber waveguide will split into two modes at near cut-off conditions when the fiber is coated with lossy dielectric nanofilms with higher refractive index. One of the two splitting modes is high lossy while the other is slightly lossy. We defined the “mode splitting coefficient” to describe the degree of mode splitting. We found that the biggest mode splitting coefficient was obtained at the mode cut-off wavelength using finite element method. Finally, we put forward an explanation towards the mode splitting phenomenon and expounded the relationship between the mode splitting and mode coupling.
关键词： Mode coupling,Mode splitting phenomenon,Finite element method,Lossy dielectric waveguide
更新于2025-09-16 10:30:52
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Normal-mode splitting in coupled high-Q microwave cavities
摘要： Three-dimensional radio frequency cavities demonstrate excellent frequency selectivity and, as such, are known for their use in RF ?lters. These cavities have potential applications in quantum information science, precision displacement metrology, and quantum electrodynamics. Additionally, coupled cavities that form a spectral doublet allow for parametric gain when incorporating mechanical elements. Here, we investigate normal-mode splitting in a pair of quarter-wave stub microwave cavities at room temperature and cryogenic environments in order to identify coupling mechanics for normal and superconducting systems. Superconducting quarter-wave stub cavities with a resonant frequency of 10 GHz are made from reactor-grade niobium and exhibit Q ranging from 105 to 109. We varied cavity-to-cavity coupling to observe several normal-mode splittings of increasing peak separation until we observed a mode crossing. The minimum observed peak separation was 7 MHz for room temperature tests and 200 kHz for cryogenic tests. We also report on values of an intrinsic quality factor for the tuning cavity as a dielectric rod is translated along its symmetry axis. The realization of coupled superconducting radio frequency (SRF) cavities of this type is a necessary step toward implementation of parametric SRF-mechanical gain.
关键词： normal-mode splitting,superconducting radio frequency cavities,quantum electrodynamics,parametric gain,high-Q microwave cavities
更新于2025-09-12 10:27:22
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MODE SPLITTING BASED ON THE COUPLING BETWEEN MODES OF TWO NANODISKS CAVITIES AND A PLASMONIC WAVEGUIDE
摘要： A metal-insulator-metal (MIM) plasmonic waveguide coupled with two nanodisks as a resonator has been examined and numerically simulated with the ?nite-di?erence time-domain (FDTD) and analytically by the Temporal Coupling Mode Theory (CMT). Based on the three-level system, the strong destructive interference between the two resonators leads to the distinct mode splitting response. The characteristics of mode splitting show that there is anomalous dispersion with the novel fast-light feature at the resonance. Meanwhile, the slow light characteristic can also be achieved in the system at wavelengths of the split modes. The relationship between the transmission characteristics and the geometric parameters is examined. The results show that the modulation depth of the mode splitting transmission spectrum of 80% with 0.175 ps fast-light e?ect of resonance can be achieved, while for the two modes these values are around 30% with ?0.18 ps slow light-e?ect. There is a good agreement between the FDTD simulated transmission features and CMT. The characteristics of the system indicate critical potential applications in integrated optical circuits such as slow-light and fast-light devices, optical monitoring, an optical ?lter, and optical storage.
关键词： slow-light,plasmonic waveguide,FDTD,mode splitting,CMT,fast-light,nanodisks
更新于2025-09-11 14:15:04
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Normal mode splitting in quantum degenerate Fermi gas in nano-cavity
摘要： We report the normal mode splitting in the fermionic displacement spectrum as a single mode light field interacts with a mechanical mode of ultra-cold quantum degenerate Fermi gas trapped inside a Fabry–Pérot cavity in the strong coupling regime. We explain the normal mode splitting in the outgoing field of the cavity field and in the field quadratures as well. As a function of system parameters, such as coupling strength between fermionic mode and field mode, number of fermionic atoms, cavity decay rate and fluctuations associated with the fermionic mode we explain the phenomenon of normal mode splitting. The low-lying fermions ensemble displays a collective density oscillation associated with particle-hole excitations, which interacts with cavity light field and lead to the observation of NMS in the fermion quadratures and light modes. The numerical results based on the present day laboratory experiments agree with the obtained analytical results.
关键词： Fabry–Pérot cavity,quantum degenerate Fermi gas,Normal mode splitting,fermionic displacement spectrum,strong coupling regime
更新于2025-09-09 09:28:46
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Numerical analysis of simultaneous measurement of the refractive index and the pressure utilizing the mode splitting in a single-opening microring resonator
摘要： In this paper, a single-opening microring resonator (SOMRR) is proposed for simultaneous measurement of refractive index (RI) and pressure. The notch angle lifts the degeneracy of clockwise and counter-clockwise WGMs to excite the mode splitting, forming the symmetric and the asymmetric standing wave modes (SWMs) in the SOMRR. Due to the different electromagnetic field energy distribution of the two SWMs, the symmetric SWM and the asymmetric SWM show different sensitivities toward the change of ambient RI and the pressure exerted on the resonator. Through the three-dimensional FDTD simulations of the two SWMs under different external environments and loads, we obtain a RI sensitivity of 77.07 nm/RIU, a high pressure sensitivity of 5.01 pm/kPa for the symmetric SWM and a RI sensitivity of 69.54 nm/RIU, a high pressure sensitivity of 5.72 pm/kPa for the asymmetric SWM. Moreover, by solving the inverse matrix of the sensitivity matrix, the resonance wavelength shifts respectively caused by the change of RI and pressure can be distinguished. For the biosensing application based on the flexible photonic device, the effect of strain-optical coupling can be eliminated by using this method. It advances the accuracy of detection results and provides a novel route to achieve its application for biosensing in the real world.
关键词： Mode splitting,Single-opening microring resonator (SOMRR),Dual-sensing,Biosensing application
更新于2025-09-04 15:30:14
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Strong coupling of a two-dimensional electron ensemble to a single-mode cavity resonator
摘要： We investigate the regime of strong coupling of an ensemble of two-dimensional electrons to a single-mode cavity resonator. In particular, we realize such a regime of light-matter interaction by coupling the cyclotron motion of a collection of electrons on the surface of liquid helium to the microwave field in a semiconfocal Fabry-Pérot resonator. For the corotating component of the microwave field, the strong coupling is pronouncedly manifested by the normal-mode splitting in the spectrum of coupled field-particle motion. We present a complete description of this phenomenon based on classical electrodynamics, as well as show that the full quantum treatment of this problem results in mean-value equations of motion that are equivalent to our classical result. For the counterrotating component of the microwave field, we observe a strong resonance when the microwave frequency is close to both the cyclotron and cavity frequencies. We show that this surprising effect, which is not expected to occur under the rotating-wave approximation, results from the mixing between two polarization components of the microwave field in our cavity.
关键词： microwave field,classical electrodynamics,cavity resonator,normal-mode splitting,two-dimensional electrons,rotating-wave approximation,Fabry-Pérot resonator,strong coupling,quantum treatment,cyclotron motion
更新于2025-09-04 15:30:14