Abstract:
An optical bench  10  is cast from a single piece of material and provided with a number of optical component supports  14  which extend upwardly from a base  12 . The optical component supports  14  are integral with the base  12 , increasing their rigidity. The bench  10  may be cast with additional material in strategic areas to allow for future optimization of the bench  10 —for example, the mounting of specific optical components throughout the bench  10 . Further, the bench  10  may be provided with regions  24, 26 , and  28  of varying rigidity by placing support struts  68  closer together in areas where greater rigidity is required. Apertures  30  may be provided in the bench  10  to enable the routing of conduits through the bench  10.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention is generally directed to optics and more specifically is directed to a bench for mounting optics in a laser system. 
     2. Description of the Prior Art 
     Benches for lasers traditionally comprise a bench base to which a number of separate component-holding supports are attached. For example, a common design for such a bench includes a bench base with a number of threaded holes set therein in a regular pattern. Threaded supports for holding optical components may be inserted into the threaded holes in the base, and the optical components may, in turn, be mounted onto the supports. 
     Such existing designs for optical benches have several shortcomings. They require a number of pieces to form the component-supporting structure. Further, the threaded connections between the component supports and the base may become loose over time, decreasing the accuracy of component placement. Also, a regular hole pattern may not coincide with the ideal mounting location of a component within the laser. In addition, if components are moved for experimentation or replacement, it is important to remember where on the base the component support was located if future setups are to replicate the original setup of the system. In general, the number of mounting components such as posts and fasteners in known optical bench systems increases the complexity and difficulty of using optical benches. There is a need for an optical bench that maintains the stability of component placement and ease of use over time while simultaneously allowing for flexibility in the setup of optical systems. The present invention is directed to such a system. 
     SUMMARY OF THE INVENTION 
     According to one embodiment of the present invention, an optical bench is provided with cast supports for holding optical components. 
     Optical benches according to the present invention may further incorporate pre-cast holes for the routing of electrical conduits, cooling conduits, and other conduits around and through the optical bench. 
     In addition, optical benches according to the present invention may incorporate kinematic mount components thereon, and in turn may be kinematically mounted to a separate mount. 
     Optical benches according to the present invention may include supports for optical components as well as non-optical components such as supporting electronics and plumbing. 
     According to some embodiments of the present invention, a cast optical bench is provided with excess material in strategic locations to enable the post-cast machining of the material for precise placement of optical components and/or supporting devices. 
     The above summary of the present invention is not intended to represent each embodiment or every aspect of the present invention. This is the purpose of the Figures and the detailed description which follow. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The foregoing and other advantages of the invention will become apparent upon reading the following detailed description and upon reference to the drawings, in which: 
         FIG. 1  is an isometric top view of an optical bench having cast optical supports; 
         FIG. 2  is an isometric top view of the optical bench of  FIG. 1  further showing threaded optical supports and additional mounting locations; 
         FIG. 3  is an isometric top view of the optical bench of  FIGS. 1 and 2  showing optical components mounted to optical supports; and 
         FIG. 4  is an isometric bottom view of the optical bench of  FIGS. 1-3 . 
     
    
    
     While the invention is susceptible to various modifications and alternative forms, specific embodiments have been shown by way of example in the drawings and will be described in detail herein. It should be understood, however, that the invention is not intended to be limited to the particular forms disclosed. Rather, the invention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the appended claims. 
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
       FIG. 1  shows an optical bench  10  according to one embodiment of the present invention. The optical bench  10  comprises a base  12  and a plurality of optical component supports  14  integral with the base  12  and projecting upwardly from a top surface  16  of the base  12 . The optical bench  10  including the base  12  and the supports  14  is a single, contiguous piece of material. Mounting slots  17  may be provided in the optical bench  10  to facilitate mounting of the optical bench  10  to another support. 
     Optical benches according to the present invention may be created from different materials and manufactured using a number of different methods. One preferred method for manufacturing an optical bench according to the present invention is to cast the entire bench  10  of a single piece of aluminum. Such casting may be done by a variety of casting methods. One method that has been successfully used is the formation of a positive model of the optical bench out of a material such as wood. A negative of the bench is then formed by the packing of sand, with the negative being filled with liquid aluminum to form the positive cast piece. The rough cast piece may be provided with extra material in strategically-located positions, which is later machined to the precision required for optical applications, such as use as a laser bench. The cast piece is put through a process of heating and cooling to stabilize the piece, and then modified as required to complete the fine details of the completed bench. While aluminum is preferred for its thermal conductivity—which prevents distortions in the bench due to hot spots—and for its stiffness relative to its weight, other materials such as titanium, beryllium, or silicon carbide may be used. 
     As shown in  FIG. 1 , the optical component supports  14  may be spaced at a variety of distances over the top surface  16  of the optical bench  10 , and spaced at a number of different heights to accommodate a variety of optical components and further to accommodate extra mounting hardware that may be necessary for the mounting of specific components.  FIG. 1  shows that most optical component supports  14  have been formed as cylinders, but it is to be understood that component supports may be formed in a variety of shapes, such as the oval shape of component support  18 . Component supports such as component support  19  may be provided with an initial shape as shown in  FIG. 1 , and later modified as necessary to support a specific component at a specific location. When cylindrical component supports are formed, it is preferred that taller component supports, such as component support  20 , be formed with a wider diameter than shorter component supports such as component support  22  to reduce the likelihood of the component supports bending or otherwise becoming misaligned. Component supports may be provided in clusters  23  to provide increased mounting options in certain areas of the bench  10 . 
     As will be understood more completely with reference to  FIG. 4 , below, optical benches according to the present invention may be designed with several different regions for mounting different types of components on the optical bench  10 . These regions may be identified based on the stability required for components mounted in the regions. For example, the optical bench shown in  FIGS. 1-3  has a first region  24  for mounting components which require the most stability (such as a main oscillator, shown in  FIG. 3 ), a second region  26  for mounting components which require an intermediate amount of stability (such as a gain module, shown in  FIG. 3 ), and a third region  28  for mounting components which require the least stability (such as support electronics, shown in  FIG. 3 ). 
     Also shown in  FIG. 1  are a plurality of apertures  30  formed in the optical bench  10  during the casting process. The apertures  30  are designed and spaced to allow conduits such as electrical conduits for optical components and support electronics to be routed through the optical bench  10 , providing for convenient routing of wiring and positioning of plumbing components. Apertures may be provided in a variety of shapes or sizes depending on the particular use of the optical bench. For example, round apertures  32  may be provided for routing single conduits or small bundles of conduits, and oval-shaped apertures  34  may be provided for routing larger conduits or larger bundles of conduits, such as incoming and outgoing cooling conduits. A side cutaway portion  35  allows for the routing of conduits away from the optical bench  10 . 
     Optical benches  10  according to the present invention may be constructed in a variety of shapes and dimensions. For example, the optical bench shown in  FIG. 1  has a length, L, of approximately 60″, a width, W, of approximately 30″, and a height, h, of approximately 4″. The optical component supports  14  are provided with heights of from about ½″ to about 6″ and diameters of from about 1.5″ to about 1.5″. 
     Turning now to  FIG. 2 , the optical bench  10  is shown with additional modifications for the mounting of optical components. Threaded holes  36  are provided in the optical component supports  14  to accept mounting screws for optical component mounts or for threaded optical components. Threaded holes  36  are also provided in the base  12  for the direct mounting of optical components or support components to the base  12 . 
     The first region  24  of the optical bench  10  is shown with kinematic mount components formed into the top surface  16  of the base  12 . Kinematic mounts are provided to fix optical components in predetermined positions while also allowing for thermal expansion of the optical components. A surface kinematic mount cone  38 , a surface kinematic mount groove  40 , and a surface kinematic mount plane  42  combine to allow kinematic mounting of a component to the first region  24 . 
     It is preferred to place the optical component supports  14  in locations that allow for versatility in mounting optical components to the bench  10 . Turning now to  FIG. 3 , an optical bench  10  is shown with components mounted thereon. A main oscillator  44  is kinematically mounted to the first region  24  of the optical bench  10 . A mirror  46  is mounted to an optical component support  14  and is adapted to reflect output radiation from the main oscillator  44 . Two lens supports  48  are used together to support a lens  50  to accept the radiation from the mirror  46 . As shown in  FIG. 3 , the lens  50  is, in turn, attached to a lens mount  52  which enables fine control of lens positioning. It is to be understood that optical components may be attached to the optical component supports of the present invention via intermediate mounts that allow for more precise positioning of the optical components. 
     Aligned pairs of supports  54  support telescope mounts  56 , which in turn support a telescope  58 . In the embodiment of  FIG. 3 , the telescope  58  directs radiation from the main oscillator  44  to a gain module  60 , which converts the radiation from the main oscillator  44  to a desired output beam. The gain module  60  is cooled by cooling conduits  62  which extend through an oval-shaped aperture  34 , and is supplied with power by an electrical conduit  64 , which extends through an aperture  30 . The gain module  60  may receive power, control signals, or other electrical inputs from support electronics  65  provided on the optical bench  10 . The gain module  60  is mounted to a supplemental support  66 , which is mounted directly to the optical bench  10 . The output beam from the gain module  60  may be directed to different components mounted throughout the optical bench. In addition to lenses, mirrors, and telescope mounts, such components as apertures, wave plates, power meters, Faraday rotators, and the like may be mounted to optical component supports or directly to threaded holes  36  in the base  12  of the optical bench. As shown in  FIG. 3 , light from the gain module  60  may be reflected away from the bench  10  by a mirror such as mirror  67 , which is shown mounted to component support  19 . The component support  19  has been modified from its original shape, shown in  FIG. 1 . The component support has been machined to hold the mirror  67  at the correct location for the application shown in  FIG. 3 . 
     Turning now to  FIG. 4 , an isometric view of the underside of an optical bench  10  is shown.  FIG. 4  shows the bench as cast and modified by post-casting holes or mounting areas. Support struts  68  are provided in the underside of the bench  10  to provide rigidity to the bench  10 . Support struts  68  in the first region  24 , which is adapted to hold components requiring the most rigidity, are spaced closely together, while support struts in the second and third regions  26  and  28  are placed progressively farther apart to support components requiring less rigidity. Conduit guides  70  are provided in the optical bench  10  to guide conduits beneath the top surface  16  of the bench  10 . Threaded holes  36  can be seen extending to the underside of the bench, as can apertures  30 . Cutout areas  71  may be provided in the support struts  68  for the routing of conduits. 
     An optical bench may be kinematically mounted to another optical support component, such as a table. Kinematic mount areas  72  are provided in the underside of the bench  10  either for direct kinematic mounting or for the attachment of intermediate kinematic mount components to the bench  10 . 
     Also shown in  FIG. 4  are cooling conduits  62  extending toward components mounted to the top surface  16  (not shown in  FIG. 4 ) of the bench  10  from main conduits  74  running through the conduit guides  70 . An electrical conduit  64  is shown extending from an aperture  30  beneath the optical bench  10  to another aperture for routing power or electrical signals to components on the optical bench  10 . 
     While the present invention has been described with reference to one or more particular embodiments, those skilled in the art will recognize that many changes may be made thereto without departing from the spirit and scope of the present invention. Each of these embodiments and obvious variations thereof is contemplated as falling within the spirit and scope of the claimed invention, which is set forth in the following claims.