Beam propagation

Ebook "Adaptive beaming and imaging in the turbulent atmosphere" due to the wide application of adaptive optical systems, an understanding of optical wave propagation in randomly inhomogeneous media has become essential, and several numerical models of individual AOS components and of efficient correction algorithms have been developed. This monograph contains detailed descriptions of the mathematical experiments that were designed and carried out during more than a decade's worth of research.

211p nhanphanguyet 28-01-2024 4 2   Download

We observed the formation of damage induced by focusing a nanosecond laser beam inside a glass block using the shadowgraph imaging technique. The damage growth was observed during some first dozens of nanoseconds of the process. The result shows that the damage growth is divided into two periods. During the laser pulse, the damage grows quickly, following the formation of laser-induced plasma. When the laser is switched off, the damage grows at a much slower rate. We propose that the growth of damage during the second period is due to the propagation of the shear wave inside the material.

4p nhanchienthien 25-07-2023 4 3   Download

In this work, we numerically study how various input beam profiles influence the linear and nonlinear light propagation at the interface of two-dimensional (2D) binary waveguide arrays. It is revealed that, due to the presence of the central homogeneous interfaced waveguides, light beams are effectively steered into the preferred direction.

7p visybill 22-03-2023 3 2   Download

An optical mode cross-connect (OMXC) between fundamental modes using a multimode interference coupler (MMI) with high performance has been proposed in this paper. These basic modes can be transmitted in turn or at the same time to any input and be able to select arbitrary outputs.

5p vigeneralmotors 13-07-2022 15 7   Download

Ebook Principles of lasers and optics includes 7 contents: Scalar wave equations and diffraction of laser radiation, Gaussian modes in optical laser cavities and Gaussian beam optics, Guided wave modes and their propagation, Guided wave interactions and photonic devices, Macroscopic properties of materials from stimulated emission and absorption, Solid state and gas laser amplifier and oscillator, Semiconductor lasers.

262p coga81 26-06-2022 47 2   Download

Applying nano-silica, as cementitious materials in concrete mixes, is expected to be an improving technique, from both mechanical properties and durability points of view. Th is study aims to analyse the characteristics of fractures in concrete beams incorporating nano - silica in bending tests, such as fracture energy, characteristics of crack length, and crack propagation.

6p vistephenhawking 26-04-2022 8 1   Download

The article presents a method to evaluate the target detection efficiency of laser fuzes operating in foggy conditions. The evaluation model is built from: The distance equation of the laser system, the attenuation of the beam in two-way propagation, the disturbances affecting the system; the signal to noise ratio SRN has determined the detection probability of the receiver

9p vicolinzheng 14-12-2021 12 0   Download

The purpose of this article is to bring some examples of misattributes (i.e., theories and models that bear some one’s name while the idea belongs to someone else) and misnomers (i.e., words or phrases that are either incorrect or inaccurate) to the attention of the colleagues in the field, and correct them so that these incorrect phrases and attributions and misnomers are not repeated in the future writings. In the process, we also discuss the purpose of a literature reviews and the need for precision of thought in naming ideas or concepts.

9p trinhthamhodang9 10-12-2020 9 0   Download

Taking into account the 125 GeV Higgs boson and radion propagators, we investigate the e−e+ production via yy collision in the Randall-Sundrum model at International Linear Collider (ILC). The observable cross-sections are calculated for the diphoton collision. The cross-sections are evaluated with dependence on the collision energy √s, the polarization of electron and positron beams.

6p tamynhan9 02-12-2020 6 1   Download

The following will be discussed in this chapter: Dipole antenna, antenna gain, antenna length, radiation mechanism, radiation pattern, antenna efficiency, beam width, types of antennas, propagation modes, noise categories.

104p nanhankhuoctai8 23-06-2020 11 1   Download

In this study, a feed-forward back-propagation Artificial Neural Network (ANN) is used to predict the stress relaxation and behavior of creep for bimaterial microcantilever beam for sensing device. Results obtained from ANSYS® 8.1 finite element (FE) simulations, which show good agreement with experimental work [1], is used to train the neural network. Parametric studies are carried out to analyze the effects of creep on the microcantilever beam in term of curvature and stress developed with time.

8p 12120609 01-06-2020 9 1   Download

A fuzzy finite element approach for static analysis of laterally loaded pile in multi-layer soil with uncertain properties is presented. The finite element (FE) formulation is established using a beam-on-two-parameter foundation model. Based on the developed FE model, uncertainty propagation of the soil parameters to the pile response is evaluated by mean of the α-cut strategy combined with a response surface based optimization technique.

9p vinobita2711 31-05-2019 23 1   Download

Electro-Optical spectral characteristics and beam quality of the high power monolithic DFB-MOPA lasers emitting at 1064 nm have been investigated at the room temperature as function of injection current. Laser beam quality is characterized by waist diameter and far-field divergence angle versus average optical output power Beam propagation ratio M2 is defined at difference intensity levels from lateral beam profile giving more detail laser behaviors at high power.

8p letanhien2309 19-02-2019 20 0   Download

A fuzzy finite-element method for analysis of laterally loaded pile in multilayer soil with uncertain properties is presented. The finite-element formulation is established using a beam-on-two-parameter foundation model. Uncertainty propagation of the soil parameters to the pile response is evaluated by a perturbation technique. This approach requires a few number of classical finite-element equations to be solved and provides reasonable results. A comparison with vertex method is made in a numerical example.

0p thienthanquydu 19-10-2018 35 0   Download

In this paper, we introduce a new two-mode (de)multiplexer based on the silicon-oninsulator (SOI) platform. The device is built on a symmetric Y-junction, a 2×2 multimode interference (MMI) waveguide and a phaseshifter in the form of a ridge waveguide which is designed using 3D scalar beam propagation method (BPM). The phase evolution in the structure is discussed in details.

12p thuyliebe 08-10-2018 29 2   Download

For over four decades there has been continuous progress in adaptive optics technology, theory, and systems development. Recently there also has been an explosion of applications of adaptive optics throughout the fields of communications and medicine in addition to its original uses in astronomy and beam propagation. This volume is a compilation of research and tutorials from a variety of international authors with expertise in theory, engineering, and technology.

228p crius75 02-01-2013 64 7   Download

This paper presents a new design method for all-optical NAND and AND logic gates based on 3x3 general interference multimode interference (GI MMI) coupler. The whole device is realized on the silicon on insulator (SOI) platform. The transfer matrix method (TMM) and three dimensional beam propagation method (3D-BPM) are used to optimally design these devices. Key words: Optical logic gate, multimode interference (MMI) coupler, silicon on insulator (SOI), beam propagation method (BPM)

7p tuanlocmuido 19-12-2012 33 1   Download

Since its first demonstration in 1960, the laser has found widespread application in diverse areas including medicine, materials processing, optical communications and information technology. The number of engineers and scientists working on lasers or in laser related fields is continuously increasing as new applications for this exciting technology are being discovered. This also means that more and more people need to gain a detailed knowledge of lasers and their characteristics.

0p echbuon 02-11-2012 55 6   Download

Advances in adaptive optics technology and applications move forward at a rapid pace. The basic idea of wavefront compensation in real-time has been around since the mid 1970s. The first widely used application of adaptive optics was for compensating atmospheric turbulence effects in astronomical imaging and laser beam propagation. While some topics have been researched and reported for years, even decades, new applications and advances in the supporting technologies occur almost daily.

266p cucdai_1 16-10-2012 48 7   Download

Fundamentals of VHF and UHF Propagation Having established the suitability of the VHF and UHF bands for mobile communications and the need to characterise the radio channel, we can now develop some fundamental relationships between the transmitted and received power, distance (range) and carrier frequency. We begin with a few relevant de®nitions. At frequencies below 1 GHz, antennas normally consist of a wire or wires of a suitable length coupled to the transmitter via a transmission line.

17p tienvovan 16-09-2010 84 5   Download