copied from a source that i can't remember so i don't have a link...
"The reason for the high price of green pointers as compared with red lies in their additional internal complexity. They use a battery powered laser diode controlled by a miniaturized circuit, just like the red ones. However, the diode uses about five times the power of the red ones and emits it's laser light at an invisible, infrared wavelength of 808nm. The infrared laser output is focused into a small crystal of Neodymium doped Yttium ortho Vanadate (NdYVO4), which then lases at a longer wavelength of 1064nm. The 1064nm output beam is absorbed in an adjacent crystal of Potassium Titanyl Phosphate (KTP) which resonates at twice the pump light frequency to produce an output of 532nm green laser light. A multilayer interference filter removes residual infra-red light, and the output is focused and collimated into a thin parallel beam. Both of the crystals are artificially grown, and must be cut, polished, and multi-coated to very small tolerances. Only a handful of companies are producing these crystals now."
jeeez, who thinks up this stuff?!?