Laser-assisted controlled in-diffusion processes for preparation of optical waveguides and ultrashallow semiconductor junctions

1995 ◽  
Author(s):  
Maria Dinescu ◽  
N. Chitica ◽  
Adriana Lita ◽  
D. Pantelica ◽  
B. Bucur ◽  
...  
Keyword(s):  
Optical Waveguides ◽  
Diffusion Processes

Buried Concentration Profiles for Optical Waveguides by One-Step Electro-Diffusion Process: Theoretical Analysis

1991 ◽  
Vol 228 ◽  
Author(s):  
Xiaoming Li ◽  
Paul F. Johnson
Keyword(s):  
Theoretical Analysis ◽  
Electric Field ◽  
Optical Waveguides ◽  
Diffusion Processes ◽  
Silver Ions ◽  
Point Of View ◽  
Concentration Profiles ◽  
Step Process ◽  
Practical Operation ◽  
One Step

IntroductionIn recent years, a two-step electric field assisted diffusion or ion-exchange technique has been extensively studied for producing buried concentration profiles in glass [1,2,3], polymer [4,5], electrooptic and semiconducting [6,7] substrate materials to fabricate buried optical waveguide devices. The technique contains two separate diffusion processes and is quite complicated, cost and time consuming. In addition, theoretical analysis of the technique is too complicated to be used for calculating and tailoring concentration profiles. Many efforts have been made to pursue a one-step process for producing buried profiles. Very recently, a novel one-step technique [8] involving electric field assisted diffusion of silver ions into glass from molten AgNO3 bath with decaying silver concentration has been developed to produce buried Ag+ concentration profiles in glass substrate. The new technique is, from the practical operation point of view, relatively simple and is a significant improvement over the conventional two-step process.

Meridional Circulation, Turbulence, and Diffusion Processes in Stars

1976 ◽  
Vol 32 ◽  
pp. 109-116 ◽  
Author(s):  
S. Vauclair
Keyword(s):  
Convection Zone ◽  
Diffusion Processes ◽  
Meridional Circulation ◽  
Diffusion Time ◽  
Work In Progress ◽  
First Results ◽  
Stellar Envelopes ◽  
And Diffusion ◽  
Turbulence And Diffusion ◽  
Hr Diagram

This paper gives the first results of a work in progress, in collaboration with G. Michaud and G. Vauclair. It is a first attempt to compute the effects of meridional circulation and turbulence on diffusion processes in stellar envelopes. Computations have been made for a 2 Mʘstar, which lies in the Am - δ Scuti region of the HR diagram.Let us recall that in Am stars diffusion cannot occur between the two outer convection zones, contrary to what was assumed by Watson (1970, 1971) and Smith (1971), since they are linked by overshooting (Latour, 1972; Toomre et al., 1975). But diffusion may occur at the bottom of the second convection zone. According to Vauclair et al. (1974), the second convection zone, due to He II ionization, disappears after a time equal to the helium diffusion time, and then diffusion may happen at the bottom of the first convection zone, so that the arguments by Watson and Smith are preserved.

TEM characterization of proton-exchanged LiNbO3 optical waveguides

1986 ◽  
Vol 44 ◽  
pp. 480-481
Author(s):  
W. E. Lee
Keyword(s):  
Refractive Index ◽  
Benzoic Acid ◽  
Optical Waveguides ◽  
Total Internal Reflection ◽  
Index Of Refraction ◽  
Optical Measurements ◽  
Lithium Ions ◽  
Wide Channel ◽  
Tem Characterization

An optical waveguide consists of a several-micron wide channel with a slightly different index of refraction than the host substrate; light can be trapped in the channel by total internal reflection.Optical waveguides can be formed from single-crystal LiNbO3 using the proton exhange technique. In this technique, polished specimens are masked with polycrystal1ine chromium in such a way as to leave 3-13 μm wide channels. These are held in benzoic acid at 249°C for 5 minutes allowing protons to exchange for lithium ions within the channels causing an increase in the refractive index of the channel and creating the waveguide. Unfortunately, optical measurements often reveal a loss in waveguiding ability up to several weeks after exchange.

Ergodic Control of Diffusion Processes

2009 ◽  
Author(s):  
Ari Arapostathis ◽  
Vivek S. Borkar ◽  
Mrinal K. Ghosh
Keyword(s):  
Diffusion Processes ◽  
Ergodic Control

Intrinsic mode theory of tapered optical waveguides

1985 ◽  
Vol 132 (6) ◽  
pp. 314 ◽  
Author(s):  
J.M. Arnold ◽  
A. Belghoraf ◽  
A. Dendane
Keyword(s):  
Optical Waveguides ◽  
Mode Theory

NMR-Study of Structure and Diffusion Processes in Li3N

1980 ◽  
Vol 41 (C6) ◽  
pp. C6-28-C6-31 ◽  
Author(s):  
R. Messer ◽  
H. Birli ◽  
K. Differt
Keyword(s):  
Diffusion Processes ◽  
Nmr Study ◽  
And Diffusion

Effect of cluster-gradient architecture of nanostructured topocomposites on features of tribointeraction with heterophased material

2020 ◽  
pp. 130-135
Author(s):  
D.N. Korotaev ◽  
K.N. Poleshchenko ◽  
E.N. Eremin ◽  
E.E. Tarasov
Keyword(s):  
Wear Resistance ◽  
Titanium Alloy ◽  
Energy Dissipation ◽  
Phase Structure ◽  
Diffusion Processes ◽  
Structural Phase ◽  
High Wear Resistance ◽  
Wear Characteristics ◽  
And Diffusion

The wear resistance and wear characteristics of cluster-gradient architecture (CGA) nanostructured topocomposites are studied. The specifics of tribocontact interaction under microcutting conditions is considered. The reasons for retention of high wear resistance of this class of nanostructured topocomposites are studied. The mechanisms of energy dissipation from the tribocontact zone, due to the nanogeometry and the structural-phase structure of CGA topocomposites are analyzed. The role of triboactivated deformation and diffusion processes in providing increased wear resistance of carbide-based topocomposites is shown. They are tested under the conditions of blade processing of heat-resistant titanium alloy.

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