Signal characters and non-classical properties of quadratically amplified squeezed vacuum

Based on the squeezed vacuum (SV) and the quadratic function of the photon number operator, we introduce the quadratically amplified squeezed vacuum (QASV) in this paper. We study the intensity, noise, squeezing effect, antibunching effect, and Wigner function of the QASVs. Compared with the SV, the QASVs have distinctive signal characters and possess peculiar non-classical properties in the proper range of interaction parameters.

Comparative analysis of properties for amplified coherent state and amplified squeezed vacuum

Two “amplified” quantum states, that is, amplified coherent state (ACS) and amplified squeezed vacuum (ASV), are considered in this paper by applying operator [Formula: see text] on coherent state (CS) and squeezed vacuum (SV), respectively. Here [Formula: see text] [Formula: see text] denotes a amplification factor and [Formula: see text]) denote the creation (annihilation) operator. Along these two lines, we make a comparative analysis of properties for ACS and ASV. The considered properties include density matrix elements, Wigner function, mean photon number, second-order autocorrelation function, and quadrature squeezing. We derive analytical expressions and make numerical simulations for all the properties. The noteworthy results include: (1) the ACS has antibunching and squeezing characters; (2) the ASV will have the bunching and antibunching effect in small initial squeezing.

Coherent state truncation by conditional interferometry

Based on a conditional interferometry proposed by Paris [Phys. Rev. A 62, 033813 (2000)], we prepare any chosen superposition of the vacuum, one-photon, and two-photon states, which is truncating from an input coherent state. Feeding two perfect single-photon states and a coherent state into the interferometry and employing two one-photon detections, the conditional state can be obtained in the signal port. Ideal and realistic features of the one-photon counting are taken into account together with the effect on the fidelity between the ideal state and the realistic case. The ideal state is just a particular case of the realistic state with the unit efficiency. We study the antibunching effect and Wigner function of the generated states. The results show that the generated states will exhibit their specular character.

Red single-photon emission from InAs/AlGaAs quantum dots

We report on single-photon emission of InAs/AlGaAs self-assembled quantum dots (QDs) grown by molecular beam epitaxy. By varying the growth conditions the QDs luminescence could be tuned over a wide wavelength range from 0.64 to 1 μm, including red part of the visible spectrum. Emission properties of individual QDs are investigated by micro-photoluminescence (μ-PL) spectroscopy using 500-nm-size etched mesa structures. Autocorrelation functions of photons from single QDs, measured in the wide spectral range demonstrate antibunching effect at zero delay time with a value of g ^(2)(0) ~ 0.17 that is a clear evidence of non-classical light.

Arik–Coon q-oscillator cat states on the noncommutative complex plane ℂq−1 and their nonclassical properties

The normalized even and odd [Formula: see text]-cat states corresponding to Arik–Coon [Formula: see text]-oscillator on the noncommutative complex plane [Formula: see text] are constructed as the eigenstates of the lowering operator of a [Formula: see text]-deformed [Formula: see text] algebra with the left eigenvalues. We present the appropriate noncommutative measures in order to realize the resolution of the identity condition by the even and odd [Formula: see text]-cat states. Then, we obtain the [Formula: see text]-Bargmann–Fock realizations of the Fock representation of the [Formula: see text]-deformed [Formula: see text] algebra as well as the inner products of standard states in the [Formula: see text]-Bargmann representations of the even and odd subspaces. Also, the Euler’s formula of the [Formula: see text]-factorial and the Gaussian integrals based on the noncommutative [Formula: see text]-integration are obtained. Violation of the uncertainty relation, photon antibunching effect and sub-Poissonian photon statistics by the even and odd [Formula: see text]-cat states are considered in the cases [Formula: see text] and [Formula: see text].

Measuring anti-bunching Effect from Single Dye Molecules and Single Quantum Dots

Antibunching is a quantum effect demonstrating clearly the quantum nature of the radiation field. Its detection through measurements of the second order correlation function is a direct proof of the presence of single molecule or single nano particle. In this paper we present the experimental setup of the Hanbury Brown - Twiss interferometer and the measurement results of the antibunching effect from single Rhodamine B dye molecules and single CdTe quantum dots in dilute solution. By fitting the second order correlation data, we derive a fluorescence lifetime of approximately 2 ns for Rhodamine B and 45 ns for CdTe quantum dots. Our results demonstrate an alternative way for determining the fluorescence lifetime using the antibunching effect.