Creation and measurement of broadband squeezed vacuum from a ring optical parametric oscillator

Serikawa, Tadashi; Yoshikawa, Jun–ichi; Makino, Kenzo; Frusawa, Akira

doi:10.1364/oe.24.028383

Cited by 58 publications

(34 citation statements)

References 41 publications

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“…We consider the case where such a field has a much larger linewidth than the cavity mode. Indeed, a squeezing bandwidth of up to ∼ GHz has been experimentally demonstrated via optical parametric amplification [38][39][40]. Because the linewidth is ∼ MHz for typical optical cavities, we can think of this cavity drive as a squeezed reservoir.…”

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confidence: 99%

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Exponentially Enhanced Light-Matter Interaction, Cooperativities, and Steady-State Entanglement Using Parametric Amplification

et al. 2018

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We propose an experimentally feasible method for enhancing the atom-field coupling as well as the ratio between this coupling and dissipation (i.e., cooperativity) in an optical cavity. It exploits optical parametric amplification to exponentially enhance the atom-cavity interaction and, hence, the cooperativity of the system, with the squeezing-induced noise being completely eliminated. Consequently, the atom-cavity system can be driven from the weak-coupling regime to the strong-coupling regime for modest squeezing parameters, and even can achieve an effective cooperativity much larger than 100. Based on this, we further demonstrate the generation of steady-state nearly maximal quantum entanglement. The resulting entanglement infidelity (which quantifies the deviation of the actual state from a maximally entangled state) is exponentially smaller than the lower bound on the infidelities obtained in other dissipative entanglement preparations without applying squeezing. In principle, we can make an arbitrarily small infidelity. Our generic method for enhancing atom-cavity interaction and cooperativities can be implemented in a wide range of physical systems, and it can provide diverse applications for quantum information processing.

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confidence: 99%

“…Moreover, the cavity mode can be squeezed typically using, e.g., a periodicallypoled KTiOPO 4 (PPKTP) crystal [48][49][50]. In order to generate a squeezed-vacuum reservoir, we can also use a PPKTP crystal with a high-bandwidth pump, so the squeezing bandwidth of up to ∼ GHz [38,39] is possible.…”

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confidence: 99%

Exponentially Enhanced Light-Matter Interaction, Cooperativities, and Steady-State Entanglement Using Parametric Amplification

et al. 2018

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“…Such a scheme encodes two real numbers from a continuous Gaussian distribution and therefore it has much higher capacity per time interval than a discrete encoding. Due to recent developments in the field of quantum optics, both coherent and displaced squeezed states can be generated with sufficient purity [31,32]. The signal state prior to modulation can be therefore described by the diagonal covariance matrix γ B = diag[V s , 1/V s ], where V s is the variance of the squeezed quadrature, here and further, without loss of generality, it is assumed to be the X quadrature (covariance matrix for a coherent state reduces to a 2 × 2 unity matrix).…”

Section: Qkd Protocolmentioning

confidence: 99%

Squeezing-enhanced quantum key distribution over atmospheric channels

2020

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We propose the Gaussian continuous-variable quantum key distribution using squeezed states in the composite channels including atmospheric propagation with transmittance fluctuations. We show that adjustments of signal modulation and use of optimal feasible squeezing can be sufficient to significantly overcome the coherent-state protocol and drastically improve the performance of quantum key distribution in atmospheric channels, also in the presence of additional attenuating and noisy channels. Furthermore, we consider examples of atmospheric links of different lengths, and show that optimization of both squeezing and modulation is crucial for reduction of protocol downtime and increase of secure atmospheric channel distance. Our results demonstrate unexpected advantage of fragile squeezed states of light in the free-space quantum key distribution applicable in daylight and stable against atmospheric turbulence.Quantum key distribution (QKD) [1-5] is one of the major practical applications of quantum information theory, which provides trusted parties (Alice and Bob) with the methods (protocols) for provably secure distribution of secret cryptographic keys so that security of the key can be verified using fundamental principles of quantum physics. One of the main requirements of QKD is the availability of a dedicated quantum channel capable of transmitting coherent quantum signals between the sending and receiving stations. In the case of fiber-optical channels, being the typical media for QKD implementations, this means a dedicated optical fiber, possibly with co-existing classical or quantum signals. However, the dedicated fiber-optical infrastructure can be unavailable, e.g., in the case of movable stations, necessity of quick channel deployment or in hostile environments. Moreover, the extra-long-distance inter-continental quantum communication over satellites relies on the free-space channels [6]. Therefore, the free-space channels are an important physical medium for QKD implementations.The main issue faced by the discrete-variable (DV) QKD protocols, based on single-photon states or weak coherent pulses and the direct photon counting, is the sensitivity of the detectors to the background light, which adds noise to the measured data. This renders standard DV QKD protocols practically unusable in the daylight conditions unless spectral filtering is applied, which adds unwanted additional loss and complexity to the set-up. At the same time, applicability and efficiency are crucial for QKD as they directly affect the secret communication, based on the quantum-secure keys. Alternatively, continuous-variable (CV) QKD protocols [7-10], based on the multiphoton coherent [11][12][13][14][15] or squeezed states [16] and homodyne quadrature detection using off-the-shelf equipment, can overcome this limitation. Indeed, a homodyne detector, which matches a signal to a narrow-band local oscillator (LO) beam, being the phase reference for the measurement, can intrinsically filter out the background radiation and make CV Q...

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“…In the following, we demonstrate the squeezing-induced noise, i.e., thermal noise and two-photon correlation, can be suppressed by employing a squeezed field to drive the cavity. In view of a highbandwidth squeezed field (up to GHz), which has been realized in experiments [51,52], it can be regarded as a squeezed reservoir due to a relatively small linewidth of typical optical cavity mode. Therefore, we assume that the cavity mode is coupled to a squeezed thermal reservoir with a squeezing parameter r e and phase θ e .…”

Section: Appendix: Effective Master Equationsmentioning

confidence: 99%

Enhancement of coherent dipole coupling between two atoms via squeezing a cavity mode

Wang

Li²,

Sampuli³

et al. 2019

Phys. Rev. A

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We propose a theoretical method to enhance the coherent dipole coupling between two atoms in an optical cavity via parametrically squeezing the cavity mode. In the present scheme, conditions for coherent coupling are derived in detail and diverse dynamics of the system can be obtained by regulating system parameters. In the presence of environmental noise, an auxiliary squeezed field is employed to suppress, and even completely eliminate the additional noise induced by squeezing. In addition, we demonstrate that our scheme enables the effective suppression of atomic spontaneous emission. The results in our investigation could be used for diverse applications in quantum technologies. *

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Creation and measurement of broadband squeezed vacuum from a ring optical parametric oscillator

Cited by 58 publications

References 41 publications

Exponentially Enhanced Light-Matter Interaction, Cooperativities, and Steady-State Entanglement Using Parametric Amplification

Exponentially Enhanced Light-Matter Interaction, Cooperativities, and Steady-State Entanglement Using Parametric Amplification

Squeezing-enhanced quantum key distribution over atmospheric channels

Enhancement of coherent dipole coupling between two atoms via squeezing a cavity mode

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