Discussion Forum

Hello Ivar,

I am currently simulating two Gaussian beams(particularly a laser with a waist of 2 micrometers and wavelength of 375 nm) coming in at some small angle(say 5 deg) from the left boundary of a rectangular domain(this contains a photopolymerizable resin with initial refractive index of 1.48). Please note that this a 2D,transient problem.

Now in order to specify the two gaussian beams at angle, I specified the propagation constant as beta=sin(5[deg])*2*pi/lambda0, where lambda0 is the wavelength of the light. the equation of the Gaussian beams that I am using is E0z=E0*(exp(-((-2e-006+y)/w0)^2)*exp(i*y*beta)+exp(-((2e-006+y)/w0)^2)*exp(-i*y*beta)) where E0 is the peak electric field which is 300e8 V/m and w0 is the waist of the laser.

Now when I run the problem, the beams do not propagate further in the domain and I cannot see the angle which I have specified. The beams seem to be just parallel to each other. Actually they should come close to each other as they propagate and then I have to study the interactions.

Can you please let me know if the equation of the beams I am using is right or not? Also, how do I specify the propagation constant? I think that the problem is that this being a transient analysis, I cannot add matched boundaries and hence cannot specify a propagation constant. Is there any way that I can specify the angle at which the beams come in?

Please let me know as soon as possible as the deadline is really near.

Your help would be greatly appreciated.

Thank you,
Avineet