We theoretically investigate the bistable spontaneous emission behavior of a single emitter in the vicinity of a hybrid V O 2 –Au nanoshell. The hybrid nanoshell is illuminated by a continuous wave pump laser. The incident beam generates heat through light absorption and causes the V O 2 to undergo a phase change from semiconductor to metallic mode. Our calculation shows that for certain values, over a range of incident laser intensity [ 0.25 ( G W / m 2 ) < I < 0.84 ( G W / m 2 )], at the resonance wavelength of the V O 2 (semiconductor)–Au nanoshell ( λ = 630 n m ), there is a reasonable bistable contrast for the two spontaneous emission rate values: the radiative and nonradiative decay rates. Our results provide important general guidelines for enabling platforms for optical switching sources and tunable sensors.
We theoretically investigate the bistable spontaneous emission behavior of a single emitter in the vicinity of a hybrid V O 2 –Au nanoshell. The hybrid nanoshell is illuminated by a continuous wave pump laser. The incident beam generates heat through light absorption and causes the V O 2 to undergo a phase change from semiconductor to metallic mode. Our calculation shows that for certain values, over a range of incident laser intensity [ 0.25 ( G W / m 2 ) < I < 0.84 ( G W / m 2 )], at the resonance wavelength of the V O 2 (semiconductor)–Au nanoshell ( λ = 630 n m ), there is a reasonable bistable contrast for the two spontaneous emission rate values: the radiative and nonradiative decay rates. Our results provide important general guidelines for enabling platforms for optical switching sources and tunable sensors.
We investigate the spontaneous emission of a two-level quantum emitter in the vicinity of a vanadium dioxide (VO2) thin film. By taking advantage of effective medium techniques to describe the dielectric constant of the VO2, we demonstrate that, in the near-field regime, the spontaneous emission rate of both electric and magnetic dipole emitters can be maximized at the insulator-to-metal phase transition temperature of the film. We find that VO2’s thermal hysteresis curve produces clear fingerprints in the emitter’s decay process, offering a new degree of freedom to dynamically control light emission at the nanoscale. We also find that the spontaneous emission rate is a non-monotonic function of the emitter transition wavelength, presenting a pronounced peak at infrared frequencies. Altogether, our results reveal that VO2 phase transition is a promising mechanism to achieve on-demand tuning of an emitter’s lifetime.
We investigate optical bistability (OB) in a hybrid system comprising a semiconductor quantum dot (SQD), a metallic nanoshell (MNS), and a cell membrane within the framework of the multipole approximation. Bistability phase diagrams plotted in the system’s parameter subspaces demonstrate that, in the weak exciton–phonon coupling regime, dynamic switching of bistable states among no-channel, single-channel, and dual-channel configurations can be achieved via precise modulation of the MNS’s dielectric shell thickness. Especially, a critical sensing threshold is identified: the absorption peak disappears and a bistable effect emerges when only 1.82% of normal cells undergo malignant transformation. Furthermore, the bistable region exhibits a gradual broadening trend with an increasing proportion of cancerous cells, yielding a quantitative and ultra-sensitive readout that underpins a highly accurate strategy for early cancer diagnosis. These findings not only deepen our fundamental understanding of bistability regulation in hybrid quantum-plasmonic systems interfaced with biological materials but also offer valuable insights for the development of next-generation optical switches and biomedical sensing platforms.
We study, theoretically, the phenomena optical bistability and multistability of a hybrid quantum-plasmonic system immersed within an optical ring cavity. The hybrid quantum-plasmonic system consists of a three-level V-type quantum emitter and a two-dimensional plasmonic metasurface of gold nanoshells. The quantum emitter and the plasmonic metasurface are placed in close proximity to each other so that a strong quantum interference of spontaneous emission occurs, which enables the strong modification of optical-bistability/ multistability hysteresis curves. Along with this, the strong interaction between the emitter and the plasmonic metasurface allows for active control of the corresponding bistable threshold intensity. Furthermore, we show that by varying the metasurface-emitter separation, a transition from bistability to multistability of the hybrid system is observed. Lastly, by introducing an additional incoherent pumping in the system, we have the emergence of phenomena, such as probe absorption and gain, with or without population inversion. The results may find technological application in on-chip nanoscale photonic devices, optoelectronics and solid-state quantum information science.
We theoretically explore the conditions for generating optical bistability (OB) in a heterodimer comprised of a semiconductor quantum dot (SQD) and a metallic nanoshell (MNS). The MNS is made of a metallic nanosphere as a core and a dielectric material as a shell. For the specific hybrid system considered, the bistable effect appears only if the frequency of the pump field is equal to (or slightly less than) the exciton frequency for a proper shell thickness. Bistability phase diagrams, when plotted, show that the dipole-induced bistable region can be greatly broadened by changing the shell thickness of the MNS in a strong exciton-plasmon coupling regime. In particular, we demonstrate that the multipole polarization not only narrows the bistable zone but also enlarges the corresponding thresholds for a given intermediate scaled pumping intensity. On the other hand, when the SQD couples strongly with the MNS, the multipole polarization can also significantly broaden the bistable region and induce a great suppression of the FWM (four-wave mixing) signal for a fixed shell thickness. These interesting findings offer a fresh understanding of the bistability conditions in an SQD/MNS heterodimer, and may be useful in the fabrication of high-performance and low-threshold optical bistable nanodevices.
In this work, we theoretically investigate optical bistability and optical response of a hybrid system consisting of semiconductor quantum dot (SQD) coupled with a vanadium dioxide nanoparticle (VO2NP) in the infrared (IR) regime. The VO2 material exists in semiconductor and metallic phases below and above the critical temperature, respectively where the particle optical properties dramatically change during this phase transition. In our calculations a filling fraction factor controls the VO2NP phase transition when the hybrid system interacts with a laser field. We demonstrate that the switch-up threshold for optical bistability is strongly controlled by filling fraction without changing the structure of the hybrid system. Also, it is shown that, the threshold of optical bistability increases when the VO2NP phases changes from semiconductor to metallic phase. The presented results have the potential to be applied in designing optical switching and optical storage.
We study how to obtain the channel-tunable bistable states in a coupled system consisting of a monolayer MoS 2 nanomechanical resonator (NR) and a metallic nanoshell (MNS) beyond the dipole approximation. The MNS is constructed by a metallic core and a dielectric shell. The calculated results show that the linear absorption spectrum exhibits some new features, such as three-phonon resonance, Rayleigh resonance, and ac-Stark resonance. In a strong exciton-plasmon coupling regime, the absorption peak and amplification peak in the absorption spectrum can be greatly enhanced by adjusting the exciton-phonon coupling strength. Especially, we plot the bistability phase diagrams in the system’s parameter space and highlight the strong dependency of the lower (upper) bistable threshold on the pumping intensity, the MNS-NR distance, and the dielectric shell thickness. The ratio of linear absorption in the upper and lower stable states can reach 42. For a given MNS with a fixed shell thickness, it is easy to achieve single-channel or dual-channel bistable states by only adjusting the exciton-phonon coupling strength via modulation of the length of the MoS 2 nanosheet along the NR axis. The findings obtained here are very useful for extensive applications such as optical memory cells and channel-tunable bistable switches.