A metallic coupler is proposed to interface a silicon on insulator (SOI) waveguide with a narrow hybrid plasmonic waveguide (200× 200 nm). The device operation is investigated and optimized to attain the best tradeoff between the mode confinement and the propagation loss. Calculations reveal that a high confinement and low loss of the energy is achieved from a silicon slab waveguide into the di...

Rectangular waveguide is one of the earliest types of transmission lines. Rectangular waveguide can be produced by hot extrusion process. In this paper, the hot extrusion process of CuZn5 rectangular waveguide was investigated by Finite Element Method (FEM). In addition, Genetic Algorithm (GA) was used to optimize the die geometry and process conditions to achieve the lowest magnitude of extrus...

Laser diode beam divergence is the main parameter for beam shaping and fiber optic coupling. Increasing the waveguide layer thickness is the conventional method to decrease the beam divergence. In this paper, the broadened asymmetric waveguide is introduced to decrease the divergence without increasing the optical power. The asymmetric waveguide was used to shift the vertical optical field to n...

the objective of this study was to evaluate different pistachio hullers and determine the proper harvest time of pistachio nuts for hulling. three pistachio hulling machines (helical drum, helical- blade drum, rubber drum) at three harvest times and 15 days interval were evaluated. the hulling efficiency, percentage of damaged nuts, faulty hulled nuts and unhulled nuts were measured at each tim...

We present an ab initio account of the paraxial complex geometrical optics (CGO) in application to scalar Gaussian beam propagation and diffraction in a 3D smoothly inhomogeneous medium. The paraxial CGO deals with quadratic expansion of the complex eikonal and reduces the wave problem to the solution of ordinary differential equations of the Riccati type. This substantially simplifies the desc...

We report a development and fabrication of an folded waveguide (FWG) antenna to produce and heat the plasma via ion Bernstein wave on the Large Helical Device (LHD) in the ion cyclotron range of frequency (ICRF). This antenna is 428 mm in height, 1050 mm in width and 3950 mm in length with 23 vanes and 24 folds. It will be installed to the horizontal vacuum port with an inclination angle of 38....

Theoretical studies [1-3] have shown that the relativistic subpicosecond electron bunches produced by high-brightness rf photoinjectors can be used to generate coherent synchrotron radiation in a free-electron maser (FEM). Furthermore, in a waveguide structure, the group velocity of the radiation can be matched to the axial bunch velocity in the helical wiggler, thus minimizing slippage in the ...

The investigation of topologically protected waves in classical media has opened unique opportunities to achieve exotic properties like oneway phonon transport, protection from backscattering and immunity to imperfections. Contrary to acoustic and electromagnetic domains, their observation in elastic solids has so far been elusive due to the presence of both shear and longitudinal modes and the...

The structured light projection (SLP) method occupies a crucial position in three-dimensional (3D) imaging technology. Different working wavelengths of can be employed depending on the situation. However, there are few lights that modulated based wavelength at present. Therefore, we have comprehensively investigated and designed Dammann grating (DG) metasurface, which controlled through multi-b...

Hardened steels are commonly used in wide areas of technologies and industries. In respect of poor machinability of these steels and requirement of expensive cutting tools, study of machining economy is a matter of importance. Thus the present study deals with the economic considerations of various hole making processes. For this purpose, the hard steel samples were machined by conventional dri...