Alrighty, I have 2 simple questions about Laser Beam Combination. I was wondering if I could take multiple Laser Diodes and direct them all at the same point and have the combined energy of the lasers at that single point. Would phase cancellation be an issue? If that doesn't work, I was thinking about using 50% silvered mirrors inorder to combine the beams, and I was wondering how much power loss is there from a 50% silvered mirror, is it 50%? or is that just the amount of light it lets through. The reason for all this is I am doing an experiment in laser pcb etching, however not actually etching the copper, but burning/charring a thin layer (like paint) off the top, which I would then wash off, or blow off with air, then throw into an etching solution. Also, could any of you recommend a good book on lasers?