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arXiv:1410.6510 · Physical Review A

Antibunching and unconventional photon blockade with Gaussian squeezed states

Marc-Antoine Lemonde, Nicolas Didier, Aashish A. Clerk

Published Dec 16, 2014• 160 citations
arXivHTMLPDF

Abstract

Photon antibunching is a quantum phenomenon typically observed in strongly nonlinear systems where photon blockade suppresses the probability of detecting two photons at the same time. Antibunching has also been reported with Gaussian states, where optimized amplitude squeezing yields classically forbidden values of the intensity correlation, ${g}^{(2)}(0)<1$. As a consequence, observation of antibunching is not necessarily a signature of photon-photon interactions. To clarify the significance of the intensity correlations, we derive a sufficient condition for deducing whether a field is non-Gaussian based on a ${g}^{(2)}(0)$ measurement. We then show that the Gaussian antibunching obtained with a degenerate parametric amplifier is close to the ideal case reached using dissipative squeezing protocols. We finally shed light on the so-called unconventional photon blockade effect predicted in a driven two-cavity setup with surprisingly weak Kerr nonlinearities, stressing that it is a particular realization of optimized Gaussian amplitude squeezing.

DOI
10.1103/physreva.90.063824

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Photon antibunching is a quantum phenomenon typically observed in strongly nonlinear systems where photon blockade suppresses the probability of detecting two photons at the same time. Antibunching has also been reported with Gaussian states, where optimized amplitude squeezing yields classically forbidden values of the intensity correlation, g(2)(0)<1{g}^{(2)}(0)<1g(2)(0)<1. As a consequence, observation of antibunching is not necessarily a signature of photon-photon interactions. To clarify the significance of the intensity correlations, we derive a sufficient condition for deducing whether a field is non-Gaussian based on a g(2)(0){g}^{(2)}(0)g(2)(0) measurement. We then show that the Gaussian antibunching obtained with a degenerate parametric amplifier is close to the ideal case reached using dissipative squeezing protocols. We finally shed light on the so-called unconventional photon blockade effect predicted in a driven two-cavity setup with surprisingly weak Kerr nonlinearities, stressing that it is a particular realization of optimized Gaussian amplitude squeezing.
The photon blockade based on weak nonlinearities is called the unconventional photon blockade. The study of the unconventional photon blockade in recent decades has mainly focused on the ${\ensuremath{\chi}}^{(3)}$ Kerr nonlinearity. In this paper, we study the photon blockade in two weakly coupled nonlinear cavities via ${\ensuremath{\chi}}^{(2)}$ nonlinearity, where ${\ensuremath{\chi}}^{(2)}$ mediates the conversion of a single photon in the cavity with high frequency into two photons with low frequency in another cavity. When the two cavity modes are driven simultaneously, our calculations show that the strong photon antibunching can be obtained in the cavity. The optimal condition for strong antibunching is found by analytic calculations and numerical simulations, and discussions of the optimal condition are presented. The differences between the present scheme and that with ${\ensuremath{\chi}}^{(3)}$ nonlinearity are discussed. This scheme is not sensitive to the change of decay rates, which makes the experimental realization easy.
The photon blockade based on weak nonlinearities is called unconventional photon blockade. The studies of the unconventional photon blockade in recent decades are all limited to Markovian approximation. In this paper, we propose a scheme to achieve a strong photon antibunching in non-Markovian reservoir. An exact non-Markovian master equation for the optical cavity coupled with a degenerate optical parametric amplifier (DOPA) is derived. We show that this unconventional photon blockade originates from the destructive interference between two paths which are formed by the DOPA pump and a driving field. Unconventional single-photon blockades that exhibit a transition from the non-Markovian to Markovian regime by controlling environmental spectral width regardless of the weakness of DOPA gain and driving field are found. We analytically derive an optimal condition for strong antibunching, which is in good agreement with that obtained by the full numerical simulation. The presented results then are compared with that given by Markovian approximation in the weak-coupling limit. Our scheme might have paved an avenue towards the investigations of unconventional photon blockades in many other non-Markovian quantum systems in quantum optics.
Abstract Unconventional photon blockade (UPB) is an important quantum phenomenon that relies on the quantum interference effect. Here, we propose coupling an optical parametric amplifier (OPA) to a Kerr nonlinear single-mode cavity in a two-photon dissipation environment, enabling strong photon antibunching based on the UPB mechanism. The optimal conditions for achieving UPB are first derived analytically. The results are subsequently compared with the second-order correlation function derived from numerical simulations, and excellent agreement is observed. The findings show that UPB is enhanced without significantly reducing the mean photon number. This further demonstrates that the width of the UPB occurrence window increases with increasing OPA coefficient and driving laser intensity. Finally, theoretical analysis reveals the physical mechanism of UPB, showing that the Kerr medium is not the dominant factor for UPB generation in this system. Thus, our work offers valuable theoretical guidance for precisely controlling UPB and optimizing single-photon source performance.
This study systematically investigates unconventional photon blockade in two coupled Kerr nonlinear cavities at resonance. By solving the master equation in the steady-state limit and calculating the equal-time second-order correlation function, the photon antibunching effect within the nonlinear regime is revealed. Through analytical derivations, four sets of optimal antibunching conditions are obtained and validated through numerical simulations, unveiling new characteristics of photon blockade. Furthermore, the influence of system parameters on photon blockade is discussed, providing valuable theoretical support for optimizing the design and implementation of single-photon sources.
In this paper, we show that photon blockade can be observed in a system with weak Kerr nonlinearities. The system consists of two spatially overlapping single-mode semiconductor cavities with tunable one- and two-photon tunneling. We find that both conventional and unconventional single-photon blockades are controllable by manipulating the phase in the hopping regardless of the weakness of nonlinearity. We refer to the photon blockade with weak nonlinearities as an unconventional photon blockade. The unconventional photon blockade effect originates from the destructive interference between different paths from the ground state to two-photon states. We analytically derive the exact optimal conditions for strong antibunching, which are in good agreement with those obtained by numerical simulations. The optimal parameters for photon blockade are derived. Based on these parameters, the semiconductor cavity systems can be used as a single-photon source in regimes of both weak and strong nonlinearities.