Small Emitter - High Flux Density

I am working on an etendue limited led project. I've worked with the CREE, Rebel, Luminus, LED Engin, and OSRAM emitters. I've lurked on your forums for some time. I'm tryin to hit a .5mm diameter target with as much light as possible? I am not constrained by power, just the laws of physics. The Rebel is actually showing the highest flux density.



Also, Do any of you guys know of an emitter that is smaller than 1mm^2?



Thanks in advance for welcoming me to the forums. I've enjoyed reading your posts for some time now.



rfus