Photonics and Optoelectronics

55-59

Authors: Hussam El Cheikh, Bruno Courant

Direct Laser Fabrication (DLF) is a rapid manufacturing process based on laser cladding technique in which parts are fabricated layer by layer. In this work, a coaxial nozzle is used to deposit 316L stainless steel on a low carbon steel substrate. In order to obtain a 3D simulation with reasonable computation time, the thermal and geometrical problems are decoupled. The clad geometry is supposed to be a half cylinder which corresponds to a suitable geometry to built a part layer by layer. The finite element method is used to simulate the heat conduction in the part during the process with a 3D modelling using the Arbitrary Langrangian-Eulerian (ALE) in (Multiphysics Comsol 3.5). This model allows predicting the temperature field in the part during the process.

33-42

Authors: Fatema Hamid Al-Saiari, S.M. Mujibur Rahman, Kazi Monowar Abedin

Computer Simulation of Fresnel Diffraction from Triple Apertures by Iterative Fresnel Integrals MethodThe Iterative Fresnel Integrals Method (IFIM) has been applied for the simulation and generation of the complete near-field Fresnel diffraction images created by triple apertures for the first time. The simulation can be performed in any PC using an included MATLAB program. Necessary formalism has been derived and simulation algorithm has been developed for this application. An interesting combination of interference effects with Fresnel diffraction has been observed in the simulation images. Transition to the expected Fraunhofer diffraction pattern from Fresnel diffraction for triple apertures is also observed by the simulations. The program can serve as a useful tool to study the complex phenomenon of Fresnel diffraction from triple apertures.

9-12

Authors: Lázaro J. Miranda Díaz

When passing a pulsing beam of polarize light of a light emitter diode (LED) or a semiconductor laser through an optical system, two photodiodes spatially arranged at 900 to each other and both with their detection surfaces parallel to the transmission shaft of light, and polarization axis oriented at 450 Keywords- Polarization; Optic; Lens; Measurement of the vertices of the edges where the photodiodes join, in the outputs of two operational amplifiers, we have two signals with the same shape in time, i.e. a pulse train with the same phase. But when you turn the polarization plane, change the radiance of the light projected onto the photodiodes, being out of phase signals to the outputs of the amplifiers, where the difference between the fronts of the pulses is proportional to the angle of rotation of the plane of polarization of polarization light. In a digital circuit phase discriminator, a pulse is obtained equal to the time difference between two sides of the rise time in the output of two amplifiers. The width of this is directly proportional to the value of rotation the plane of polarization of light, that is to say, the greater the rotation is, the greater the width of this will be.

20-24

Authors: I. Ashraf, T. Mahmood, V. Lakshminarayanan

We propose a quantum search method, based on Grover’s algorithm. We show that to search for a single marked element from an unsorted search space of N elements the number of queries required using this algorithm varies as N**1.3 when compared to N**1/2 for the Grover’s algorithm.