Gas flow laser oscillator

Claim 1

A gas flow laser oscillator comprising: an elongate enclosure having an axis; a first reflector disposed at one end of the inside of said enclosure; a second reflector disposed inside the enclosure facing opposite the first reflector, the edges of the second reflector being fixed in a sealed manner to the walls of the enclosure to form therein a first chamber between the first and the second reflectors and a second chamber between the second reflector and the other end of the enclosure, the second reflector including an opening putting the first and second chambers into communication with each other; means for inserting a laser active gas into the second chamber, the gas passing through the opening in the second reflector, the cross section of the opening and pressure of the gas being chosen to form turbulant flow in the first chamber; means for extracting the gas from the first chamber; and two electrodes disposed in the first chamber and connected to a source of electric current for establishing an electric discharge in the active gas in such a manner as to generate a coherent light beam which is reflected on the first and second reflectors; the improvement wherein: the first reflector comprises first and second substantially conical reflecting surfaces, said surfaces being coaxial with said axis and oppositely inclined relative to a plane normal thereto, with the first conical reflecting surface being in the center of the first reflector and being immediately surrounded by the second conical reflecting surface, the second reflector being plane and centered on said axis, said opening being axial in such a manner that an annular first beam path of said coherent light radiation coming from the second reflector is reflected in succession on said second and first conical surfaces so as to constitute a second beam path about said axis which beam is cylindrical and which occupies substantially all the volume left free by the annular first beam path, the second beam path penetrating into said second chamber via the opening in said second reflector; and wherein the oscillator further comprises: a convex third reflector centered on the axis, and disposed in the second chamber in such a manner as to reflect the cylindrical second beam path along a divergent co-axial third beam path; and a plane fourth reflector disposed on the axis between the second and third reflectors, said fourth reflector being provided with a central apperture and being inclined relative to a plane normal to the axis so that firstly; the second bearing path and an axial portion of the third beam path passes through the apperture; and secondly the remaining peripheral portion of the third beam path is reflected by the fouth reflector along a fourth beam path; the first, second, third, and fourth reflectors constituting an unstable resonant cavity capable of amplifying coherent light radiation, a concave fifth reflector disposed to concentrate the energy of the laser radiation along a fifth beam path to a point on said enclosure means such that the laser radiation escapes.