Mini Lasers With Megapower To Burn

Do you want to get rid of freckles or clear up age spots? No problem--if your dermatologist has a laser the size of a two-drawer filing cabinet. Now, these and other big medical and industrial lasers can be crammed into much smaller boxes, thanks to Paradigm Laser Inc., a startup in East Rochester, N.Y. Using its lasers, Lihtan Technologies Inc. in San Anselmo, Calif., has already unveiled a microwave-oven-size system.

Paradigm's trick? Necklaces of pinhead-size laser diodes around the main laser, a rod made of garnet crystal. Normally, light from diodes is too weak to activate laser rods. That limits "diode-pumped" lasers to a few watts of power. But Paradigm rings each half-inch of the rod with a 70-diode array. The result: An inch-long laser emits 100 watts, enough for surgery. A 3-inch, 2,000-watt laser easily cuts steel.

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