2D Line Renderer material issues

Hi guys!

I'm trying to create a laser beam effect in a top-down 2D game. Although there's a few ways of doing this, I've deicded to go with the Line Renderer approach. Functionally, I have it working fine, however I'm having significant difficulty understanding how to use textures/materials/shaders to achieve the visual effect I want.

I've attempted a fair amount of research on the subject, but most of it applies to 3D and I have trouble wrapping my head around how it applies to a 2D environment.

This is a rough image of the effect I'm trying to achieve:


And these are some of the textures I've been attempting to use:


I've tried applying the textures to materials with different shaders but i'm not really getting any results other than a line with an odd colour or sometimes no colour. Can anyone give me a basic rundown on what I should be doing?

I don't need anyone to actually design me a texture, but just an explanation on how to correctly apply them.

Thanks!