Quantum state of an injected TROPO above threshold : purity, Glauber function and photon number distribution

In this paper we investigate several properties of the full signal-idler-pump mode quantum state generated by a triply resonant non-degenerate Optical Parametric Oscillator operating above threshold, with an injected wave on the signal and idler modes in order to lock the phase diffusion process. We determine and discuss the spectral purity of this state, which turns out not to be always equal to 1 even though the three interacting modes have been taken into account at the quantum level. We have seen that the purity is essentially dependent on the weak intensity of the injected light and on an asymmetry of the synchronization. We then derive the expression of its total three-mode Glauber P-function, and calculate the joint signal-idler photon number probability distribution and investigate their dependence on the injection

Non-linear and quantum optics of a type II OPO containing a birefringent element Part 1: Classical operation

We describe theoretically the main characteristics of the steady state regime of a type II Optical Parametric Oscillator (OPO) containing a birefringent plate. In such a device the signal and idler waves are at the same time linearly coupled by the plate and nonlinearly coupled by the $\chi^{(2)}$ crystal. This mixed coupling allows, in some well-defined range of the control parameters, a frequency degenerate operation as well as phase locking between the signal and idler modes. We describe here a complete model taking into account all possible effects in the system, \emph{i.e.} arbitrary rotation of the waveplate, non perfect phase matching, ring and linear cavities. This model is able to explain the detailed features of the experiments performed with this system.Comment: To be published in EPJ

Non-linear and quantum optics of a type II OPO containing a birefringent element Part 2 : bright entangled beams generation

We describe theoretically the quantum properties of atype-II Optical Parametric Oscillator containing a birefringent plate which induces a linear coupling between the orthogonally polarized signal and idler beams and results in phase locking between these two beams. As in a classical OPO, the signal and idler waves show large quantum correlations which can be measured experimentally due to the phase locking between the two beams. We study the influence of the waveplate on the various criteria characterizing quantum correlations. We show in particular that the quantum correlations can be maximized by using optimized quadratures.Comment: to be published in Eur. Phys. J.

Survey of functional and non-functional fish hatchery in Jigawa State, Nigeria

This study was conducted in the five emirate zones of Jigawa. The number of functional and non-functional fish hatcheries were investigated in the state. The results showed that there were 35 fish hatcheries in the state, and private ownership (57.14%) dominate the government ownership (42.16% ), all with less than 1000,000 fingerlings production annually. The study also indicate that out of the 35 fish hatcheries, 15 were found to be functional in operation and 20 are found existing but not functional in operation. Based on the field survey, all the respondent are of the opinion that the level of production and number of functional hatcheries in the state are low. Recommendations were made on how to improve hatchery operation that could help to boost aquaculture development in the state

Compact Source of EPR Entanglement and Squeezing at Very Low Noise Frequencies

We report on the experimental demonstration of strong quadrature EPR entanglement and squeezing at very low noise sideband frequencies produced by a single type-II, self-phase-locked, frequency degenerate optical parametric oscillator below threshold. The generated two-mode squeezed vacuum state is preserved for noise frequencies as low as 50 kHz. Designing simple setups able to generate non-classical states of light in the kHz regime is a key challenge for high sensitivity detection of ultra-weak physical effects such as gravitational wave or small beam displacement

Mapping photonic entanglement into and out of a quantum memory

Recent developments of quantum information science critically rely on entanglement, an intriguing aspect of quantum mechanics where parts of a composite system can exhibit correlations stronger than any classical counterpart. In particular, scalable quantum networks require capabilities to create, store, and distribute entanglement among distant matter nodes via photonic channels. Atomic ensembles can play the role of such nodes. So far, in the photon counting regime, heralded entanglement between atomic ensembles has been successfully demonstrated via probabilistic protocols. However, an inherent drawback of this approach is the compromise between the amount of entanglement and its preparation probability, leading intrinsically to low count rate for high entanglement. Here we report a protocol where entanglement between two atomic ensembles is created by coherent mapping of an entangled state of light. By splitting a single-photon and subsequent state transfer, we separate the generation of entanglement and its storage. After a programmable delay, the stored entanglement is mapped back into photonic modes with overall efficiency of 17 %. Improvements of single-photon sources together with our protocol will enable "on demand" entanglement of atomic ensembles, a powerful resource for quantum networking.Comment: 7 pages, and 3 figure

Conditional preparation of a quantum state in the continuous variable regime: generation of a sub-Poissonian state from twin beams

We report the first experimental demonstration of conditional preparation of a non classical state of light in the continuous variable regime. Starting from a non degenerate OPO which generates above threshold quantum intensity correlated signal and idler "twin beams", we keep the recorded values of the signal intensity only when the idler falls inside a band of values narrower than its standard deviation. By this very simple technique, we generate a sub-Poissonian state 4.4dB below shot noise from twin beams exhibiting 7.5dB of noise reduction in the intensity difference.Comment: 4 pages, Accepted in Phys. Rev. Let

Urinary schistosomiasis in communities around Kiri Lake, Shelleng Local Government Area, Adamawa State, Nigeria

The objectives of the study were to determine the prevalence of urinary schistosomiasis in the different communities, the intensity of infection, prevalence among gender and age groups and to relate infection with parent’s occupation. A study on the prevalence of urinary schistosomiasis was conducted in four villages around Kiri Lake in Shelleng Local Government Area, Adamawa State, Nigeria. Two hundred and thirty two urine samples were collected from four primary school children randomly selected from within the four study communities. Overall, prevalence of urinary schistosomiasis was 48% (111/232), with males recording 49% (69/142) and females 47% (42/90). The total mean egg count (MEC) was 8.3. There was no significant difference in prevalence between males and females (P˃0.05). Prevalence was higher among age groups, with the 13-15 year old age group having the highest 62.96% (17/27) and the 4-6 year old age group had the least 37% (19/52). There was no statiscally significant difference in prevalence among the different age groups (P>0.05). Infection was also high among children of fishermen 59.09% (13/22), followed by farmers’ children 56.25% (45/80) and the least prevalence was among children of teachers 20% (3/15). Old Banjiram had the highest infection of 91% (21/23), while Kwadadai had the least 36.8% (21/57) (P<0.05). Old Banjiram and children in the 10-12 years age group had the highest mean egg count of 10.6 and 9.4 respectively. The study reveals a high prevalence of urinary schistosomiasis. And therefore portable water source should be made functional in all communities surrounding the lake. While rehabilitation and repair of the existing water borehole system in the community should be effected as well as drilling new additional boreholes to serve their water needs. Commun JASEMity participatory health education on this neglected tropical disease in the area is needed on knowledge of the disease, the intermediate host and transmission pattern. Since school children harbour infection and are a source of infection of schistosomiasis in endemic communities, planning and provision for their treatment should be considered in control programmes.Keywords: Schistosoma haematobium, Prevalence, Kiri lake, Socio-economic, School children, Nigeri

Independent nonclassical tests for states and measurements in the same experiment

We show that one single experiment can test simultaneously and independently both the nonclassicality of states and measurements by the violation or fulfillment of classical bounds on the statistics. Nonideal measurements affected by imperfections can be characterized by two bounds depending on whether we test the ideal measurement or the real one.Comment: 9 pages, 3 figures. Proceedings of 17th CEWQO 201