Notes

Clashes and also environmentally friendly footprint throughout MENA countries: implications with regard to eco friendly terrestrial habitat.
We present a scheme for enhancing Goos-Hänchen shift of light beam that is reflected from a coherent atomic medium in the Kretschmann-Raether configuration. The complex permittivity of the medium can be coherently controlled and has significant influence on the surface plasmon resonance (SPR) at the metal-medium interface. By tuning the atomic absorption, the internal damping of SPR system can be modulated effectively, thereby leading to giant positive and negative lateral displacements. The refractive index of medium determines the SPR angle. Thus the peak position of the beam shift becomes tunable. As the optical response of the coherent medium depends on the intensity and detuning of the controlling fields, we are able to conveniently manipulate the magnitude, the sign, and the angular position of Goos-Hänchen shift peaks.AlGaN heterostructure solar-blind avalanche photodiodes (APDs) were fabricated on a double-polished AlN/sapphire template based on a separate absorption and multiplication (SAM) back-illuminated configuration. By employing AlGaN heterostructures with different Al compositions across the entire device, the SAM APD achieved an avalanche gain of over 1×105 at an operated reverse bias of 92 V and a low dark current of 0.5 nA at the onset point of breakdown. These excellent performances were attributed to the acceleration of holes by the polarization electric field with the same direction as the reverse bias and higher impact ionization coefficient of the low-Al-content Al0.2Ga0.8N in the multiplication region. However, the Al0.2Ga0.8N layer produced a photocurrent response in the out of the solar-blind band. To retain the solar-blind detecting characteristic, a periodic Si3N4/SiO2 photonic crystal was deposited on the back of the AlN/sapphire template as an optical filter. This significantly improved the solar-blind characteristic of the device.Laser induced plasmas (LIPs) method is a highly regarded approach to evaluate the chemical composition of materials. But the strong self-absorption of the radiation seriously affects its accuracy. Meanwhile, the model based on self-absorption phenomenon makes its application very difficult. In this work, a self-absorption internal standard (SAIS) model is proposed for detection of the multi-element concentrations of complex constituent material with a single emission line of the element in laser plasmas. A typical LIPs experiment system is set up to generate plasmas, and the soil is selected as a test sample. The average electron temperature (0.975 eV) and electron density (1.44×1018 cm-3) are determined by the Boltzmann plot and emission lines Stark broadening, respectively. The plasmas are diagnosed as in local thermodynamic equilibrium condition. The emission lines selected to calculate the concentration of sample contain a wide set of kt values (0.575×10-30∼37.2×10-30 m3). Then, the concentrations of some elements are calculated by the model using single emission line of each element. It is found that the concentrations of the five elements (Ti, Fe, Mg, Al, Si) calculated by SAIS model are relatively consistent with the results of the traditional chemical testing methods. This indicated that the SAIS model is an effective and neat method for multi-element concentrations detection of complex constituent materials.SWIFT spectroscopy (Shifted Wave Interference Fourier Transform Spectroscopy) is a coherent beatnote technique that can be used to measure the temporal profiles of periodic optical signals. While it has been essential in understanding the physics of various mid-infrared and terahertz frequency combs, its ultimate limits have not been discussed. We show that the envelope of a SWIFTS interferogram is physically meaningful and is directly related to autocorrelation. We derive analytical expressions for the SWIFTS signals of two prototypical cases-chirped pulses from a mode-locked laser and a frequency-modulated comb-and derive scaling laws for the noise of these measurements, showing how it can be mitigated. Finally, we confirm this analysis by performing the first SWIFTS measurements of near-infrared pulses from femtosecond lasers, establishing the validity of the technique for highly-dispersed sub-picojoule pulses.An optical switch based on an electrowetting prism coupled to a multimode fiber has demonstrated a large extinction ratio with speeds up to 300 Hz. Electrowetting prisms provide a transmissive, low power, and compact alternative to conventional free-space optical switches, with no moving parts. The electrowetting prism performs beam steering of ±3° with an extinction ratio of 47 dB between the ON and OFF states and has been experimentally demonstrated at scanning frequencies of 100-300 Hz. The optical design is modeled in Zemax to account for secondary rays created at each surface interface (without scattering). Simulations predict 50 dB of extinction, in good agreement with experiment.TiO2 channel waveguides were fabricated using a DC sputter deposition process, followed by photolithography and reactive ion etching. A SiO2 cladding was deposited using evaporation. SEM, TEM and Raman measurements indicate the presence of both an amorphous and a crystalline phase. As the layer thickness increases, poly-crystalline structures start forming. Loss measurements were performed by imaging the scattered light from the top of the channel waveguides and fitting an exponential decay to the intensity profile. Propagation losses of 7.8 ± 0.52 dB/cm at a wavelength of 632.8 nm and 0.68 ± 0.46 dB/cm at a wavelength of 1010 nm were experimentally characterized.Quantum communication aims to provide absolutely secure transmission of secret information. State-of-the-art methods encode symbols into single photons or coherent light with much less than one photon on average. For long-distance communication, typically a single-mode fiber is used and significant effort has been devoted already to increase the data carrying capacity of a single optical line. Here we propose and demonstrate a fundamentally new concept for remote key establishment. Our method allows high-dimensional alphabets using spatial degrees of freedom by transmitting information through a light-scrambling multimode fiber and exploiting the no-cloning theorem. https://www.selleckchem.com/products/apr-246-prima-1met.html Eavesdropper attacks can be detected without using randomly switched mutually unbiased bases. We prove the security against a common class of intercept-resend and beam-splitting attacks with single-photon Fock states and with weak coherent light. Since it is optical fiber based, our method allows to naturally extend secure communication to larger distances.
My Website: https://www.selleckchem.com/products/apr-246-prima-1met.html