Abstract: A method and apparatus are disclosed for drilling gas, oil or geothermal wells in geological formations and for "fracing" the pay zones of such wells to increase recovery, using a laser beam projected into the well bore along a beam guide so as to make available laser energy adequate to melt or vaporize the formation under down-hole conditions. Fluid circulation is established via the beam guide to keep the beam path adequately free of contaminants to permit drilling. A novel orifice window is provided to allow transmitting the high energy beam from the surface into a high-pressure, down-hole environment.