Complete EM Field of Gaussian Beam: References & Pointers

AI Thread Summary
The discussion focuses on finding references for the complete electromagnetic field of a Gaussian beam, specifically seeking exact formulas for Ex, Ey, and Ez. It highlights that the Gaussian profile is common in real laser beams and notes that the exact formulas relate to separable Helmholtz equations in Cartesian coordinates. A key reference mentioned is "Analysis of vector Gaussian beam propagation and the validity of paraxial and spherical approximations" by Carl G. Chen et al., published in JOSA A, which explores vector representations beyond the paraxial approximation. Additionally, a suggestion is made to look into Yariv's "Quantum Electronics" for further insights. The complexity of the full vector representation is acknowledged, indicating that the topic is intricate and challenging.
pervect
Staff Emeritus
Science Advisor
Homework Helper
Insights Author
Messages
10,396
Reaction score
1,573
Does anyone have any references or pointers to the complete electromagnetic field of a "Gaussian Beam"?

By Gaussian, I mean that for a beam propagating in the z direction, a cross-section of the beam in the x-yplane has

|E| = k exp( -(x^2+y^2)/w^2 )

see for instance
http://en.wikipedia.org/wiki/Gaussian_beam

I gather that real laser beams tend to have this sort of "Gaussian" profile. However, I haven't been able to find out anything with exact formulas for Ex, Ey, and Ez. \nabla \cdot E = 0 seems to imply that Ez is not zero.
 
Physics news on Phys.org
Actually,the exact formulas for Ex,Ey,Ez are the same as separable Helmholtz eqations in Cartesian coordinates. The Gaussian packet(beam) form is just a kind of B.C. You can simply superpose plane waves(in coordinate) to get a Gaussian shape. In this sense, kx,ky are generally non-zero,so Ez could also be non-zero. It´s not a problem though, since this is not plane wave at all.
 
There is a book by Yariv..Quantum Electronics.Wiley 1967
I guess you should find good stuff there.

Best Regards,

DaTario
 
Note that one of the reasons for Gaussian to be used is its easy doing Fourier Transform (spectrum)
 
The full vector representation is disgustingly complicated :smile: .

I was only able to find the vector representation in an optics journal, the reference is;

'Analysis of vector Gaussian beam propagation and the validity of paraxial and spherical approximations.' Carl G. Chen, Paul T. Konkola, Juan Ferrera, Ralf K. Heilmann, Mark L. Schattenburg, JOSA A, Volume 19, Issue 2, 404-412, (2002).

You won't be able to access it though unless your institution has a subsciption with the OSA.

On the paper, I noticed that it goes beyond the Paraxial approximation, a vector solution including the paraxial approximation may be less complicated.

Claude.
 
Claude Bile said:
The full vector representation is disgustingly complicated :smile: .

Heh - I was afraid of that, thanks.

I was only able to find the vector representation in an optics journal, the reference is;

'Analysis of vector Gaussian beam propagation and the validity of paraxial and spherical approximations.' Carl G. Chen, Paul T. Konkola, Juan Ferrera, Ralf K. Heilmann, Mark L. Schattenburg, JOSA A, Volume 19, Issue 2, 404-412, (2002).

I don't have access to that paper, unfortunately, but I did find an interesting reference online when I included "Helmholtz" in my keywords

http://www.hep.princeton.edu/~mcdonald/examples/oblate_wave.pdf

I don't think this paper directly answers my question, but it does give me an idea of how messy the problem is :-)
 
Thread 'Question about pressure of a liquid'
I am looking at pressure in liquids and I am testing my idea. The vertical tube is 100m, the contraption is filled with water. The vertical tube is very thin(maybe 1mm^2 cross section). The area of the base is ~100m^2. Will he top half be launched in the air if suddenly it cracked?- assuming its light enough. I want to test my idea that if I had a thin long ruber tube that I lifted up, then the pressure at "red lines" will be high and that the $force = pressure * area$ would be massive...
I feel it should be solvable we just need to find a perfect pattern, and there will be a general pattern since the forces acting are based on a single function, so..... you can't actually say it is unsolvable right? Cause imaging 3 bodies actually existed somwhere in this universe then nature isn't gonna wait till we predict it! And yea I have checked in many places that tiny changes cause large changes so it becomes chaos........ but still I just can't accept that it is impossible to solve...
Back
Top