arXiv subjects

Shengguo Guan

Publications and source records attributed to Shengguo Guan.

6 recordsLinked to original sources

arXiv2019

Photon blockade in a bi-mode nonlinear nano-cavity embedded with a quantum-dot

We study the interaction between a quantum-dot and a bi-mode micro/nano-optical cavity composed of second-order nonlinear materials. Compared with the Jaynes-Cummings (J-C) model, except for a coherent weak driving field, a strong pump light illuminates the two-mode optical cavity. Analytical results indicate that the model exhibits abundant non-classical optical phenomena, such as conventional photon blockade induced by the nonlinear interaction between polaritons. It constitutes unconventional photon blockade induced by quantum interference due to parametric driving. We compare the photon statistical properties and average photon number of the proposed model, J-C model, and double-mode driven optical cavity under the same parameters and the proposed model can obtain stronger antibunching photons and higher average photon number.

quant-ph↗

arXiv2019

Conventional and unconventional photon blockade effects in an atom-cavity system

A two-level system interacting with a cavity field is an important model for investigating the photon blockade (PB) effect. Most work on this topic has been based on the assumption that the atomic transition frequency is resonant with the fundamental mode frequency of the cavity. We relax this constraint and reexamine PB in a more general atom--cavity system with arbitrary atomic and cavity detunings from a driving field. The results show that when the signs of the atomic and cavity detunings are the same, PB occurs only in the strong-coupling regime, but for opposite signs of the atomic and cavity detunings, strong photon antibunching is observed in both the weak- and strong-coupling regimes and a better PB effect is achieved compared with the case when the signs are the same. More interestingly, we find that this PB arises from quantum interference for both weak and strong nonlinearities. These results deepen our understanding of the underlying mechanism of PB and may be help in the construction of single-photon sources with higher purity and better flexibility using atom--cavity systems.

quant-ph↗

arXiv2018

Pulse-regulated single-photon generation via quantum interference in a $χ^{(2)}$ nonlinear nanocavity

A scalable on-chip single-photon source at telecommunications wavelengths is an essential component of quantum communication networks. In this work, we numerically construct a pulse-regulated single-photon source based on an optical parametric amplifier in a nanocavity. Under the condition of pulsed excitation, we study the photon statistics of the source using the Monte Carlo wave-function method. The results show that there exits an optimum excitation pulse width for generating high-purity single photons, while the source brightness increases monotonically with increasing excitation pulse width. More importantly, our system can be operated resonantly and we show that in this case the oscillations in $g^{(2)}(0)$ is completely suppressed.

quant-ph↗

arXiv2017

Phonon antibunching effect in coupled nonlinear micro/nanomechanical resonator at finite temperature

In this study, we investigate the phonon antibunching effect in a coupled nonlinear micro/nanoelectromechanical system (MEMS/NEMS) resonator at a finite temperature. In the weak driving limit, the optimal condition for phonon antibunching is given by solving the stationary Liouville-von Neumann master equation. We show that at low temperature, the phonon antibunching effect occurs in the regime of weak nonlinearity and mechanical coupling, which is confirmed by analytical and numerical solutions. We also find that thermal noise can degrade or even destroy the antibunching effect for different mechanical coupling strengths. Furthermore, a transition from strong antibunching to bunching for phonon correlation has been observed in the temperature domain. Finally, we find that a suitably strong driving in the finite-temperature case would help to preserve an optimal phonon correlation against thermal noise.

quant-ph↗

arXiv2017

Optical and atomic stochastic resonances in the driven dissipative Jaynes-Cummings model

In this work we study the stochastic resonance (SR) effect in a driven dissipative Jaynes-Cummings model. The SR effect is systematically studied in the semiclassical and full quantum frameworks and in both cases we find that SRs simultaneously occur for the optical and atomic freedoms. In particular, at zero temperature quantum SR can be induced merely by vacuum fluctuations. The qualitative features of semiclassical SR and quantum SR are similar, but the parameter region of quantum SR are shifted from the semiclassical region due to the widely-used factorization in obtaining semiclassical equations of motion. Our results provide a theoretical basis for experimentally observing and studying the SR phenomenon of the Jaynes-Cummings model in the quantum regime.

quant-ph↗

arXiv2016

Test of non-Newtonian gravitational force at micrometer range

We report an experimental test of non-Newtonian gravitational forces at mi- crometer range. To experimentally subtract off the Casimir force and the electrostatic force background, differential force measurements were performed by sensing the lateral force between a gold sphere and a density modulated source mass using a soft cantilever. The current sensitivity is limited by the patch electrostatic force, which is further improved by two dimensional (2D) force mapping. The preliminary result sets a model independent constraint on the Yukawa type force at this range.

gr-qc↗