We have investigated the two-photon nonlinearity attained by a finite-sized excitonic system placed inside of a cavity, paying attention to the dependence on the system size $N$ . The two-photon nonlinearity is evaluated by utilizing semiclassical optical responses. In the quantum-dot limit, the excitonic system behaves as a single two-level system with an enhanced coupling to the cavity mode. In the bulk limit, the nonlinear phase shift decreases as $N$ is increased, proportionally to ${N}^{\ensuremath{-}1∕2}$.We have investigated the two-photon nonlinearity attained by a finite-sized excitonic system placed inside of a cavity, paying attention to the dependence on the system size $N$. The two-photon nonlinearity is evaluated by utilizing semiclassical optical responses. In the quantum-dot limit, the excitonic system behaves as a single two-level system with an enhanced coupling to the cavity mode. In the bulk limit, the nonlinear phase shift decreases as $N$ is increased, proportionally to ${N}^{\ensuremath{-}1∕2}$.

Physical Review AJun 24, 200511 citations

Stepwise Phase Modulation of an Atomic Wavefunction in a Cavity

Ilkka Juhani Tittonen, Igor Jex

European Quantum Electronics Conference (EQEC)Jan 1, 19960 citations

TWO-PHOTON NONLINEAR INTERACTION MEDIATED BY CAVITY QUANTUM ELECTRODYNAMICS SYSTEMS

Kazuki Koshino, Hajime Ishihara

Exploiting the field-amplification effect of a cavity, the possibility of optical nonlinearity by only two photons was indicated experimentally. In the present article, we review our recent analysis of the two-photon dynamics in a cavity quantum electrodynamics (QED) system. Since a cavity-QED system is highly dispersive around its resonances, the shapes of photonic pulses are significantly deformed through interaction with the system. Thus, the present analysis is based on a formalism beyond single-mode approximations. The external photon field is treated rigorously as a continuum, which enables us to handle the two-photon wavefunction in the space representation. The degree of optical nonlinearity in a two-photon state is quantified by comparing the output wavefunction with the linear output wavefunction. It is revealed that the semiclassical optical response theory can be applied for evaluation of the two-photon optical nonlinearity. The two-photon nonlinearity appears not purely as a phase shift in the output wavefunction. The degradation of the fidelity between the output wavefunction and the linear output wavefunction always occurs, which hinders the application of this nonlinear effect as a quantum phase gate. The optimum condition for maximizing the two-photon nonlinearity is clarified, suggesting that pulse shape control is more essential than the Q-value control of the cavity QED system.Exploiting the field-amplification effect of a cavity, the possibility of optical nonlinearity by only two photons was indicated experimentally. In the present article, we review our recent analysis of the two-photon dynamics in a cavity quantum electrodynamics (QED) system. Since a cavity-QED system is highly dispersive around its resonances, the shapes of photonic pulses are significantly deformed through interaction with the system. Thus, the present analysis is based on a formalism beyond single-mode approximations. The external photon field is treated rigorously as a continuum, which enables us to handle the two-photon wavefunction in the space representation. The degree of optical nonlinearity in a two-photon state is quantified by comparing the output wavefunction with the linear output wavefunction. It is revealed that the semiclassical optical response theory can be applied for evaluation of the two-photon optical nonlinearity. The two-photon nonlinearity appears not purely as a phase shift in the output wavefunction. The degradation of the fidelity between the output wavefunction and the linear output wavefunction always occurs, which hinders the application of this nonlinear effect as a quantum phase gate. The optimum condition for maximizing the two-photon nonlinearity is clarified, suggesting that pulse shape control is more essential than the Q-value control of the cavity QED system.

International Journal of Modern Physics BJul 20, 20064 citations

Two-Photon Blockade with Second-Order Nonlinearity in Cavity Systems

Qi‐Cheng Wu, Xingyuan Zhang, Yueming Wang +4 more

International Journal of Theoretical PhysicsFeb 1, 20225 citations

We have investigated the two-photon nonlinearity attained by a finite-sized excitonic system placed inside of a cavity, paying attention to the dependence on the system size

N

. The two-photon nonlinearity is evaluated by utilizing semiclassical optical responses. In the quantum-dot limit, the excitonic system behaves as a single two-level system with an enhanced coupling to the cavity mode. In the bulk limit, the nonlinear phase shift decreases as

N

is increased, proportionally to ${N}^{\ensuremath{-}1∕2}$.