Thanks @JonD for sharing. Is ‘angularly uniform’ the same as ‘collimated’? I can imagine filament light source being not spatially uniform, but why is it angularly uniform?
In the case of TIRF, I understand the need of collimated beam for TIRF illumination on the sample. But spatial uniform illumination is important as well. Do you mean the collimated beam is generated at the cost of even illumination?