We consider an infinite square-cell lattice of elastic beams with a semi-infinite crack. Symmetric and antisymmetric bending modes of fracture under remote loads are examined. The related long-wave asymptotes corresponding to a continuous anisotropic bending plate are also considered. In the latter model, the symmetric mode is characterized by the square-root type singularity, whereas the antis...

Coherent detection of orbital angular momentum in radio Report Title The angular momentum propagated by a beam of radiation has two contributions: spin angular momentum (SAM) and orbital angular momentum (OAM). SAM corresponds to wave polarisation, while OAM-carrying beams are characterized by a phase which is a function of azimuth. We demonstrate experimentally that radio beams propagating OAM...

Non-diffracting Bessel beams, including zero-order and high-order Bessel Beams which carry orbital angular momentum (OAM), enable a variety of important applications in optical micromanipulation, sub-diffraction imaging, high speed photonics/quantum communication, etc. The commonly used ways to create Bessel beams, including an axicon or a digital hologram written to a spatial light modulator (...

We demonstrate production of short wavelength beams with nonclassical intensity correlations and quadrature entanglement using second harmonic generation in a nonlinear resonator with two output ports. The two output beams at the harmonic frequency have no direct interaction but are both nonlinearly coupled to a common pump beam. The nonlinear coupling produces amplitude and phase correlations ...

Simplified theories governing behavior of beams and plates keeping the fundamental characteristics of the being modeled objects are proposed and discussed. By simplification, we mean decrease of order of partial differential equations (PDEs) with respect to spatial coordinates. Our approach is used for both discrete and continuous models. An advantage of Padé approximation is addressed. First p...

performance of structures during recent earthquakes shows that the effect of vertical component of earthquake (vce) could be considered as one of the main causes of bridges collapse. in most of bridge design codes, for seismic analysis of bridges, vce is not taken into account or a distinguished method isn’t presented for assessment of vce. in the present work, the effect of vce on two existing...

A new scheme is presented to directly produce fundamental, second-, and third-harmonic three-color continuous-variable (CV) entangled beams by cascaded quasi-phase-matched third-harmonic generation (THG) in an optical cavity. THG can be achieved with high efficiency through a coupled sum-frequency process between the second-harmonic and the fundamental fields. It is demonstrated that the three ...

Three different methods have been discussed to verify continuous variable entanglement of intense light beams. We demonstrate all three methods using the same set–up to facilitate the comparison. The non–linearity used to generate entanglement is the Kerr–effect in optical fibres. Due to the brightness of the entangled pulses, standard homodyne detection is not an appropriate tool for the verif...

The continuous variable multicolor entangled state of optical modes is one of the essential quantum resources for constructing quantum information networks composed of many nodes and channels. It has been well proved that the cascaded nondegenerate optical parametric oscillators (CNOPOs) are the most successful devices to produce bright entangled optical beams with different wavelengths. Here, ...