We experimentally investigate a double-pass parametric down-conversion scheme for producing pulsed, polarization-entangled photon pairs with high visibility. The amplitudes for creating photon pairs on each pass interfere to compensate for distinguishing characteristics that normally degrade two-photon visibility. The result is a high-flux source of polarization-entangled photon pulses that does not require spectral filtering. We observe quantum interference visibility of over 95% without the use of spectral filters for $200\phantom{\rule{0.3em}{0ex}}\mathrm{fs}$ pulses, and up to 98.1% with $5\phantom{\rule{0.3em}{0ex}}\mathrm{nm}$ bandwidth filters.We experimentally investigate a double-pass parametric down-conversion scheme for producing pulsed, polarization-entangled photon pairs with high visibility. The amplitudes for creating photon pairs on each pass interfere to compensate for distinguishing characteristics that normally degrade two-photon visibility. The result is a high-flux source of polarization-entangled photon pulses that does not require spectral filtering. We observe quantum interference visibility of over 95% without the use of spectral filters for $200\phantom{\rule{0.3em}{0ex}}\mathrm{fs}$ pulses, and up to 98.1% with $5\phantom{\rule{0.3em}{0ex}}\mathrm{nm}$ bandwidth filters.

arXiv:quant-ph/0604051Physical Review AJul 6, 200621 citations

Optimization Of Entangled Photon Pair Sources

Kadir Durak, Esra Malyer, Can EraydÃ„Â±n

Computer Science and Information TechnologyAug 30, 20180 citations

Entangled-photon generation from a quantum dot in a microcavity through pulsed laser irradiation

Kazunori Shibata, Hiroshi Ajiki

We theoretically investigate fast and highly efficient entangled-photon generation by irradiating a quantum dot (QD) embedded in a microcavity with short laser pulses. We evaluate the optimized width and field strength of the pulses for achieving a high population of an excited state as an entangled-photon source. We also calculate the emission time of the entangled photon pair as a function of the cavity quality factor $Q$ . The shortest emission time reaches $3/(4g)$ under the condition $Q={\ensuremath{\omega}}_{0}/(4g)$, where $g$ is the coupling frequency between the cavity photon and excited states of the QD and ${\ensuremath{\omega}}_{0}$ is the excitation frequency of the QD. The QD-cavity system has a potential for fast and efficient generation of high-quality entangled-photon pairs.We theoretically investigate fast and highly efficient entangled-photon generation by irradiating a quantum dot (QD) embedded in a microcavity with short laser pulses. We evaluate the optimized width and field strength of the pulses for achieving a high population of an excited state as an entangled-photon source. We also calculate the emission time of the entangled photon pair as a function of the cavity quality factor $Q$. The shortest emission time reaches $3/(4g)$ under the condition $Q={\ensuremath{\omega}}_{0}/(4g)$, where $g$ is the coupling frequency between the cavity photon and excited states of the QD and ${\ensuremath{\omega}}_{0}$ is the excitation frequency of the QD. The QD-cavity system has a potential for fast and efficient generation of high-quality entangled-photon pairs.

Physical Review AApr 22, 20143 citations

Time reflection of light from a quantum perspective and vacuum entanglement

Anatoly A. Svidzinsky

If a boundary between two static media is moving with a constant superluminal velocity, or there is a sudden change of the refractive index with time, this yields generation of entangled pairs of photons out of vacuum propagating in the opposite directions. Here we show that during this process, entanglement of Minkowski vacuum is transferred to the entanglement of the generated photon pairs. If initially an electromagnetic pulse is present in the medium the photon generation is stimulated into the pulse mode, and since photons are created as entangled pairs the counter-propagating photon partners produce a pulse moving in the opposite direction, which is known as time reflection. Thus, time reflection occurs due to stimulated generation of the entangled photon pairs out of entangled vacuum and no photons in the original pulse are in fact being reflected. This is different from the mechanism of light reflection from spatial inhomogeneities for which no photons are generated.If a boundary between two static media is moving with a constant superluminal velocity, or there is a sudden change of the refractive index with time, this yields generation of entangled pairs of photons out of vacuum propagating in the opposite directions. Here we show that during this process, entanglement of Minkowski vacuum is transferred to the entanglement of the generated photon pairs. If initially an electromagnetic pulse is present in the medium the photon generation is stimulated into the pulse mode, and since photons are created as entangled pairs the counter-propagating photon partners produce a pulse moving in the opposite direction, which is known as time reflection. Thus, time reflection occurs due to stimulated generation of the entangled photon pairs out of entangled vacuum and no photons in the original pulse are in fact being reflected. This is different from the mechanism of light reflection from spatial inhomogeneities for which no photons are generated.

Optics ExpressApr 4, 20248 citations

200\phantom{\rule{0.3em}{0ex}}\mathrm{fs}

pulses, and up to 98.1% with

5\phantom{\rule{0.3em}{0ex}}\mathrm{nm}

bandwidth filters.

Q

. The shortest emission time reaches

3/(4g)

under the condition $Q={\ensuremath{\omega}}_{0}/(4g)$, where

g

is the coupling frequency between the cavity photon and excited states of the QD and ${\ensuremath{\omega}}_{0}$ is the excitation frequency of the QD. The QD-cavity system has a potential for fast and efficient generation of high-quality entangled-photon pairs.