I'm looking for ultra bright thru-hole LEDs for my research, but am new at this whole thing. For my application, I want to place one linear LED array on each side of the forearm and image through the skin layer. I need the light to be powerful enough to go through thick biological tissue while not being harmful. As far as I've learned, heat seems to be the only source of potential danger, so I'm guessing that a heatsink would solve this problem?
Since I have only rudimentary experience with LEDs, what kind of power and/or radiant intensity would you recommend? Currently I'm using an array of fifty 5mm thru-hole 80mW/sr LEDs and its not nearly enough, so I need brighter ones (assuming brightness is the determining factor here).
What are the advantages and disadvantages of thru-hole versus surface-mount? The device is size-sensitive (cost not so much), and I will be hand-soldering the arrays.
Finally, is there any advantage at all of using laser diodes over ultra-bright LEDs? As far as I'm aware, the main differences are collimation and coherence, and neither attribute is relevant here.
Again, I apologize for the beginner questions, and thank you for your time.