Complete EM Field of Gaussian Beam: References & Pointers

In summary, the author discusses the various approximations that can be made to calculate the field of a Gaussian beam, and how each approximation may lead to a different final field.
  • #1
pervect
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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. [itex]\nabla \cdot E = 0[/itex] seems to imply that Ez is not zero.
 
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  • #2
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.
 
  • #3
There is a book by Yariv..Quantum Electronics.Wiley 1967
I guess you should find good stuff there.

Best Regards,

DaTario
 
  • #4
Note that one of the reasons for Gaussian to be used is its easy doing Fourier Transform (spectrum)
 
  • #5
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.
 
  • #6
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 :-)
 

1. What is a Gaussian beam?

A Gaussian beam is a type of laser beam that has a bell-shaped intensity profile, with most of the energy concentrated in the center and gradually decreasing towards the edges.

2. What is the complete EM field of a Gaussian beam?

The complete EM field of a Gaussian beam includes both the electric and magnetic components, which are perpendicular to each other and to the direction of propagation.

3. What is the importance of understanding the complete EM field of a Gaussian beam?

Understanding the complete EM field of a Gaussian beam is crucial for various applications, such as laser beam shaping, optical trapping, and laser material processing.

4. Are there any analytical solutions for the complete EM field of a Gaussian beam?

Yes, there are analytical solutions for the complete EM field of a Gaussian beam, which involve complex mathematical equations and integrals.

5. What are some references and pointers for further reading on the complete EM field of Gaussian beams?

Some recommended references for further reading include "Gaussian Beams in Optics" by Govind P. Agrawal, "Introduction to Optics" by Frank L. Pedrotti, and "Laser Beam Shaping: Theory and Techniques" by Fred M. Dickey and Scott C. Holswade.

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