Discussion Forum

Hello, I want to excite my geometry using Gaussian beam. I have read some blogs on comsol about it. I just have some few questions which was not answered in those blogs. 1. I want my beam travelling in the negative z so, I selected beam orientation along z axis. But the blogs said the default setting is propagating in the positive z direction. If I want to use the in built function, how do I ensure it travels in the negative z direction. If I enter -emw.K0 in the wavenumber field, will it solve this? If not how then? 2. If I want to use Scattering Boundary conditions, for a gaussian beam, what is the appropriate scattered wave type, is it plane wave, cylindrical wave or spherical wave. 3. My beam is travelling from air through another medium. One blog said to use emw.K instead of emw.K0. I have already ticked resolve wave in lossy medium in my mesh. which of the two wave number default in COMSOL is appropriate. 4. For the Focal plane along the axis, I did not get the explanations well. is it the point where my beam originates (in my example, Z= 0 cm) or the point where my beam interacts with the second medium (z = -0.2cm), if it is the later, then should I enter 0.2cm or -0.2cm? please refer to my geometry for better understanding. Thanks.