Upgrade your mirrors to SI coated mirrors, using a HQ ZnSe lens and even pushing up to a beam expander will all boost power. The ideal order of experimenation for lowest cost would be changing out for a higher quality lens labeled HQ ZnSE lens. Next would be SI mirrors, which will absorb less heat and reflect better, the last would be to use a beam expander which expands the beam, reducing the heat signature on the mirrors and makes a tighter focal width.
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CAN BOOST THE POWER OF MY BLACKTOOTH LASER?