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Gaussian focused beam, 4.2a

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Dear All,

I have issue. I have silver block on the glass.

I want to illuminate it from the bottom (so light first propagate through the glass),

but I want to illuminate it with Gauss focused beam (I do that for the scattered field).

Do you maybe know some equation of Gauss focused beam (in 3D)?


Cheers and thanks


2 Replies Last Post 9 nov. 2012, 09:28 UTC−5
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)

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Posted: 1 decade ago 9 nov. 2012, 07:36 UTC−5
Hi

it depends on how many physics, if you are simulating the EM field, you could use the Definitions - gaussian function to modulate the spatial intensity distribution in X-Y (assuming you are propagating along Z) but then to get it to "focus down, you would need to add a phase term (as function of X-Y) to map the curvature at the entrence of your "inlet" boundary. By the way the simplest is probably to add a cylindrical coordinate along your beam axis and express everything in this coordinate frame, this reduces one dimension for the functions to define

--
Good luck
Ivar
Hi it depends on how many physics, if you are simulating the EM field, you could use the Definitions - gaussian function to modulate the spatial intensity distribution in X-Y (assuming you are propagating along Z) but then to get it to "focus down, you would need to add a phase term (as function of X-Y) to map the curvature at the entrence of your "inlet" boundary. By the way the simplest is probably to add a cylindrical coordinate along your beam axis and express everything in this coordinate frame, this reduces one dimension for the functions to define -- Good luck Ivar

Please login with a confirmed email address before reporting spam

Posted: 1 decade ago 9 nov. 2012, 09:28 UTC−5

Hi

it depends on how many physics, if you are simulating the EM field, you could use the Definitions - gaussian function to modulate the spatial intensity distribution in X-Y (assuming you are propagating along Z) but then to get it to "focus down, you would need to add a phase term (as function of X-Y) to map the curvature at the entrence of your "inlet" boundary. By the way the simplest is probably to add a cylindrical coordinate along your beam axis and express everything in this coordinate frame, this reduces one dimension for the functions to define

--
Good luck
Ivar


Thanks for advice.

I will try on that way.

Cheers
[QUOTE] Hi it depends on how many physics, if you are simulating the EM field, you could use the Definitions - gaussian function to modulate the spatial intensity distribution in X-Y (assuming you are propagating along Z) but then to get it to "focus down, you would need to add a phase term (as function of X-Y) to map the curvature at the entrence of your "inlet" boundary. By the way the simplest is probably to add a cylindrical coordinate along your beam axis and express everything in this coordinate frame, this reduces one dimension for the functions to define -- Good luck Ivar [/QUOTE] Thanks for advice. I will try on that way. Cheers

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