Laser optical resonator

Abstract

The reflectors in a laser are mounted in precise axial alignment by means of an elongated mounting structure made of a material of low thermal coefficient of expansion which serves to prevent reflector misalignment due to temperature changes in the laser, the elongated mounting structure also including an associated member made of a material of high thermal conductivity which serves to direct heat away from the elongated mounting structure along the length, further reducing any temperature effects thereon. In addition, a kinematic mounting structure is provided for further enhancing the alignment stability characteristics of the plasma tube and resonator structure.

What is claimed is: 
     
       1. A laser comprising an active lasing medium, means for creating a population inversion in said lasing medium, an optical resonator including a pair of reflectors aligned with each other and about the active lasing medium to form the optical beam path of the laser and for stimulating the emission of radiation along said path, a pair of reflector adjustment plates in which said reflectors are mounted, and means for accurately positioning and aligning said reflectors including at least three spaced-apart rods made of a material having a low thermal coefficient of expansion, the rods extending parallel with but displaced from the optical path, the outer ends of the rods being coupled to the reflector adjustment plates, sleeves surrounding .[.at least a part of each of the rods and.]. .Iadd.each of said rods over the entire length and said rods are segmented and are coupled together by fixed bearings within each sleeve and each sleeve .Iaddend.being made of a material of high thermal conductivity for minimizing thermal gradients along said rods, and means positioned along said rods for thermally coupling by thermal conduction said sleeves for minimizing thermal gradients both among and along said sleeves and said rods. 
     
     
       2. A laser as claimed in claim 1 wherein said sleeves are made of aluminum. 
     
     
       3. A laser as claimed in claim 1 wherein said thermal coupling means comprises a plurality of support members spaced-apart along the laser supporting the plurality of sleeves. 
     
     
       4. A laser as claimed in claim 2 including a plurality of cradle members associated with certain ones of said support members, said cradle members serving to support said active lasing medium and to equalize the temperature among the resonator rods. 
     
     
       5. A laser as claimed in claim .[.3.]. .Iadd.4 .Iaddend.including a main base plate and flexure means for mounting said ones of said support members on said main base plate. 
     
     
       6. In a laser including an elongated plasma tube and a magnet solenoid surrounding and supporting the plasma tube, and wherein the invention comprises an improved optical resonator comprising a plurality of supports mounted in the laser and positioned in longitudinally spaced-apart relationship along said magnet solenoid, at least certain ones of said supports secured to said magnet solenoid to support the plasma tube and magnet solenoid in the laser, a plurality of sleeves made of a material of good thermal conductivity extending beyond the two furthest apart supports, a pair of resonator end plates, separate ones of the resonator end plates being mounted on each end of the plurality of sleeves, a reflector support plate movably mounted in longitudinal alignment on each resonator end plate, each reflector support plate having a reflector mounted thereon in axial alignment with the plasma tube a, bearing member positioned within each sleeve at a point between the ends of the sleeve, and a plurality of at least three resonator rods made of material of low thermal coefficient of expansion, one in each sleeve, extending from engagement at one end against the bearing member outwardly through the sleeves to engagement against the reflector support plates, said reflector support plates including adjustment means at the point of contact with the ends of the resonator rods for accurate alignment of the relfector support plate and associated reflector with the plasma tube and opposite reflector, and wherein said plurality of supports are positioned between said .[.shields.]. .Iadd.sleeves .Iaddend.and said solenoid for providing a thermal conduction path between said sleeves for minimizing thermal gradients both along and among said sleeves and rods.  .[.7. A laser as claimed in claim 1 wherein each of said rods are segmented and are coupled 
     
     
        together by fixed bearings with each sleeve..]. 8. A laser as claimed in 
     
     
        claim 2 wherein said rods are made of quartz. 9. A laser as in claim 6 wherein each of said rods comprises at least two sections, said sections being coupled together by bearing member positioned within each sleeve at a point between the ends of the sleeve.  .[.10. In a laser including a lasing medium, an optical resonator comprising a pair of reflectors, at least one reflector adjustment plate in which a reflector is mounted, and wherein the improvement comprises means for accurately positioning and aligning said reflectors comprising a plurality of at least three spaced-apart rods made of a material having a low thermal coefficient of expansion, said rods extending parallel with and along the laser optical beam path, the outer ends of the rods being coupled to the reflector adjustment plate, sleeves surrounding each of the rods and being made of a material having high thermal conductivity, and means positioned along said rods for thermally coupling said sleeves by providing a thermal conduction path therebetween for minimizing thermal gradients both between and along 
     
     
        said rods..]. 11. A laser as in claim 1 wherein two of the planes defined by the axes of said at least three parallel rods are orthogonal to each 
     
     
        other. 12. A laser as in claim 6 wherein .Iadd.said plurality of supports comprises three supports which are parallel to each other and wherein .Iaddend.two of the planes defined by the axes of said three parallel .[.resonator supportrods.]. .Iadd.supports .Iaddend.are orthogonal to each 
     
     
        other. 13. An improved optical resonator for a laser for accurately aligning and maintaining in alignment a pair of reflectors comprising: a. a base plate;   b. first means for preventing misalignment of said reflectors due to temperature gradients across and along the optical resonator comprising i. a pair of reflector adjustment plates in which said reflectors are mounted,   ii. three spaced-apart rods made of a material having a low thermal coefficient of expansion, wherein the rods extend parallel with but displaced from .[.the optical beam path of the laser.]. .Iadd.one another .Iaddend.and the outer ends of the rods being coupled to the reflector adjustment plates,   iii. sleeves surrounding .[.at least a part of each of the rods and.]. .Iadd.each of said rods over the entire length and said rods are segmented and are coupled together by fixed bearings within each sleeve and each sleeve .Iaddend.being made of a material of high thermal conductivity for minimizing thermal gradients along said rods, and   iv. means positioned along said rods for thermally coupling by thermal conduction said sleeves for minimizing thermal gradients both among and along said sleeves and said rods; and     c. means for mounting said sleeves to said base plate, said mounting means including second means for preventing misalignment of said reflectors due to mechanical forces exerted on said base during the operation of the   
     
     
        laser. 14. An improved optical resonator for a laser as in claim 13 wherein said thermal coupling means comprises a plurality of support members spaced-apart along .[.the.]. .Iadd.a .Iaddend.laser supporting the 
     
     
        plurality of sleeves. 15. An improved optical resonator for a laser as in claim 14 including a plurality of cradle members associated with certain ones of said support members, said cradle members serving to support .[.the.]. .Iadd.an .Iaddend.active lasing medium and to equalize the 
     
     
        temperature among said rods. 16. An improved optical resonator as claim 15 wherein said second means comprises a first flexure means for mounting said cradle members on said resonator support members and second flexure 
     
     
        means for mounting said resonator support members on said base plate. 17. An improved optical resonator as in claim 16 wherein two of the planes defined by the axes of said .[.at least.]. three rods are orthogonal to 
     
     
        each other. 18. An improved optical resonator as in claim 13 wherein two of the planes defined by the axis of said .[.at least.]. three rods are orthogonal to each other.