Generation of Entangled Photon Holes using Quantum Interference

In addition to photon pairs entangled in polarization or other variables, quantum mechanics also allows optical beams that are entangled through the absence of the photons themselves. These correlated absences, or ``entangled photon holes'', can lead to counter-intuitive nonlocal effects analogous to those of the more familiar entangled photon pairs. Here we report an experimental observation of photon holes generated using quantum interference effects to suppress the probability that two photons in a weak laser pulse will separate at an optical beam splitter.Comment: 4 pages, color figures, submitted to Phys. Rev.

Non-diffracting Optical Beams in a Three-level Raman System

Diffractionless propagation of optical beams through atomic vapors is investigated. The atoms in the vapor are operated in a three-level Raman configuration. A suitably chosen control beam couples to one of the transitions, and thereby creates a spatially varying index of refraction modulation in the warm atomic vapor for a probe beam which couples to the other transition in the atoms. We show that a Laguerre-Gaussian control beam allows to propagate single Gaussian probe field modes as well as multi-Gaussian modes and non-Gaussian modes over macroscopic distances without diffraction. This opens perspectives for the propagation of arbitrary images through warm atomic vapors.Comment: 8 pages, 7 figure

Performance of Photon-Pair Quantum Key Distribution Systems

We analyze the quantitative improvement in performance provided by a novel quantum key distribution (QKD) system that employs a correlated photon source (CPS) and a photon-number resolving detector (PNR). Our calculations suggest that given current technology, the CPR implementation offers an improvement of several orders of magnitude in secure bit rate over previously described implementations

New Solution for ICT/ELV Infrastructure Project Reporting Using Datalink Technique System

In infrastructure project, a failure on reliable project reporting will lead to Variation Order (VO) and Project Delay issues. It is now a normal phenomenon, which leads to many negative effects such as lawsuits, claims, loss of productivity and revenue, which may also lead to contract termination. Hence, the research aims to develop a new solution system program, called Datalink Technique System (DTS) to solve the problems that occur in an infrastructure project. The objective is to eliminate the loss and reduce the project cost. However, it is not limited to that as in future it can also be applied to others. DTS introduces the new advanced technologies system solution and reliable, yet it is still consistent with the current approach to manage the project. The program produces data/information correctly and precisely

Role of entanglement in two-photon imaging

The use of entangled photons in an imaging system can exhibit effects that cannot be mimicked by any other two-photon source, whatever the strength of the correlations between the two photons. We consider a two-photon imaging system in which one photon is used to probe a remote (transmissive or scattering) object, while the other serves as a reference. We discuss the role of entanglement versus correlation in such a setting, and demonstrate that entanglement is a prerequisite for achieving distributed quantum imaging.Comment: 15 pages, 2 figure

Odd-Order Aberration-Cancellation in Correlated-Photon Imaging

We discuss a correlated two-photon imaging apparatus that is capable of producing images that are free of the effects of odd-order aberration introduced by the optical system. We show that both quantum-entangled and classically correlated light sources are capable of producing the desired spatial-aberration cancelation

Assessment of natural radionuclides in rivers of Pahang State Malaysia

Investigations were conducted to determine the radionuclide concentration levels in the major rivers in Pahang state, Malaysia. Since the rivers are the main sources for water supply in the state, it is important to measure natural radionuclide concentrations in the rivers. Seventeen water samples were collected from major rivers in Pahang state. The concentration of uranium, thorium and potassium were analyzed using inductively coupled plasma mass spectrometer (ICP-MS). The samples were found to contain permissible levels of radionuclides with a mean activity concentrations of uranium, thorium and potassium found to be 8.49 ± 0.34 mBq L-1, 1.74 ± 0.27 mBq L-1and 77.85 ± 0.96 mBq L-1respectively. The ratio between thorium and uranium concentration is found to be 3:4 due to the higher solubility of uranium than thorium in water. Radionuclide concentrations obtained were compared with the terrestrial gamma radiation dose rate measured around the area. A good relation was observed between uranium and thorium concentrations with gamma dose rate obtained around the area while no relation was found between the potassium concentrations with gamma dose rate. Significance of the results obtained is discussed

Lyot-based Multi-wavelength Fiber Laser

A multi-wavelength fiber laser which is based on a Lyot filter is experimentally demonstrated. A combination of four-wave mixing in a highly nonlinear fiber and Lyot filter mechanism in the laser cavity is able to generate multi-wavelength with relatively high extinction ratio (ER). At the input current of 100mA, six laser lines with ER more than 5 dB are successfully generated. The wavelength spacing for the multi-wavelength is 0.15nm, corresponding to the characteristics of the Lyot filter used

Study of Land Cover Change Using Multi Layer Perceptron and Logistic Regression Methods in Gunung Ciremai National Park

The development of land cover change is important to understand, so that the pattern of future land cover changes can be predicted and its negative impacts can be prevented or reduced. Various modeling approaches have been widely used to analyze land cover changes. The common modeling methods used for analyzing land cover changes are Multi-layer Perceptron (MLP) and Logistic Regression (Logit). This research is designed to assess the accuracy of modeling of land cover change with MLP and Logit methods in Gunung Ciremai National Park. The result indicated that the accuracy of both methods was very good with kappa values were 0,8991 and 0,8989 for MLP and Logit respectively. Therefore, the model can be applied to predict land cover change in Gunung Ciremai National Park in the future

Efficient graphene-based photodetector with two cavities

We present an efficient graphene-based photodetector with two Fabri-P\'erot cavities. It is shown that the absorption can reach almost 100% around a given frequency, which is determined by the two-cavity lengths. It is also shown that hysteresis in the absorbance is possible, with the transmittance amplitude of the mirrors working as an external driving field. The role of non-linear contributions to the optical susceptibility of graphene is discussed.Comment: 10 pages, 8 figures. published version: minor revisio