Abstract:
Modular electrical, mechanical and optical components allow for the building of a laser combiner system that can be used, for example, for biological research that allows different lasers to be easily added to or removed from a laser system. Each individual laser can be packaged into a module which can be added to or taken away from the laser system with relative ease. Each of the modules can be controlled via a control module that allows one or more of varying of power levels, switching on/off, shutter control and diagnostic/status information monitoring.

Description:
RELATED APPLICATION DATA 
       [0001]    This application claims the benefit of and priority under 35 U.S.C. §119(e) to U.S. Patent Application No. 60/984,971, filed Nov. 2, 2007, entitled “Scalable, Reconfigurable, Laser Combiner,” which is incorporated herein by reference in its entirety. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    Lasers have become more widely used in most technical areas of research in commercial products. The recent introduction of solid-state laser modules that are much smaller and longer lasting than gas lasers has expanded the number and scope of laser applications. For example, in the bio-medical field, lasers are being increasingly used for imaging and diagnostics. A confocal microscope, for example, is usually used with a laser for imaging. 
       FIELD OF THE INVENTION 
       [0003]    This invention generally relates to laser systems. More specifically, an exemplary embodiment of this invention relates to a modular, scalable, and reconfigurable laser combiner. Even more specifically, an exemplary embodiment of the invention relates to a modular, stackable laser combiner. 
       SUMMARY OF THE INVENTION 
       [0004]    Most single, solid-state laser modules have only one wavelength output. Many applications require more than one laser at different wavelengths. In the example of the confocal microscope, having multiple available wavelengths allows multiple channel imaging for different contrast agents. A common way to combine laser beams is to use a polychromatic mirror (dichroic) to reflect one laser beam along the path of another. Typical applications of this sort require precise alignment of the two beams. In particular, if the output of the combined laser beams will be coupled into a fiber optic cable, the beams must be precisely aligned to each other and the fiber. Because of this, great care must be taken with issues such as mechanical stability, vibration isolation, and thermal expansion. A typical solution would have the lasers, combining optics and fiber on a single solid platform. 
         [0005]    A single solid platform can solve the issues of stability, but for commercial systems it requires reconfiguration of the internal optics to change the system by adding a laser, for example. As lasers are expensive, often customers want to pick and choose the most appropriate wavelengths for their application which is not necessarily the standard commercial offering. This leads to a large number of customized systems. 
         [0006]    In addition to simply combining laser beams, many applications require fast control of the output wavelengths and intensity. In particular, many applications require fast shuttering of the individual beams so that one or more of the available wavelengths can be selected as the output as well as general shuttering functionality, e.g., the ability to turn on/off all the lasers. Many applications also require a means to individually control the output intensity of the various beams. This can be done with mechanical shutters and neutral density filter wheels. This can also be accomplished with particular models of lasers by controlling the lasers directly with electrical signals or commands. For some past applications, acousto-optics were used to simultaneously control the wavelengths and intensity of the beams. 
         [0007]    Accordingly, one exemplary embodiment of the invention is directed toward a modular electrical, mechanical and optical system for building a laser combiner system that can be used, for example, for biological research that allows different lasers to be easily combined and recombined into a complete system. Each individual laser can be packaged into a module which can be added to or taken away from a complete system with relative ease. This aids manufacturing, because a laser can be built into a module without necessarily requiring the complete system. The individual modules can be quickly combined into a complete system thereby also enabling easily field-upgradeable systems. 
         [0008]    One laser combiner system uses between one and six lasers to form about 62 different optional combinations. This results in a large number of possible configurations, which makes each system essentially custom. With this typical laser combiner system, all the lasers that go in the system and all the optics are required to begin production of the system. Upgrading this system by, for example, adding a laser, usually requires remanufacture of the whole system, and at least is very difficult to do in the field. 
         [0009]    In accordance with an exemplary embodiment of the present invention, each laser option is built into a separate module that can be “stacked” with other modules to form a combined laser. Each exemplary module comprises the laser, power supply, electronics and combiner optics. Individual modules can be held rigidly relative to all the other modules, with a mechanical (inter)locking system. In accordance with this exemplary embodiment, there is a top module, which goes on top of the stack of laser modules which handles the laser switching, control, shutter, etc. This means that instead of hundreds of possible laser combiner systems, there only needs to be seven different modules built for any possible configuration. Additional modules can handle extra features such as multiple output switching, high-speed modulation, laser scanning, and the like. Because this new module system is completely expandable, it is no longer limited to only six lasers. To field upgrade a system would only require inserting a new module into the stack. 
         [0010]    Modules can preferably be stacked such that higher wavelength lasers are always below shorter wavelength lasers. Dichroics are used to combine beams. They are chosen such that the dichroic in a given module transmits any wavelengths higher than the wavelength of that module&#39;s laser. The desired output is controlled, for example, by a tunable filter or by shutters in front of the individual lasers. 
         [0011]    Each module can also include one or more electrical connectors which receive input from the module above it and passes the input to the module below it. The inputs can include, for example, power, electrical control signals, laser safety signals, on/off signals and lights, and the like. A simple jumper system can allow the module to know which layer it is in the stack. 
         [0012]    According to one exemplary embodiment of the present invention, there is provided an apparatus for packaging individual laser modules into a mechanical structure that can be combined with other such structures such that 
         [0013]    Individual laser modules are combined with beam alignment optics, combining optics, electronics, heat sinks, and mechanical and/or thermal stabilization into one mechanical unit (stack). 
         [0014]    Stacks can be mechanically attached to other stacks to form a combined laser beam. 
         [0015]    Stacks can be combined in any quantity as the availability of lasers and combining optics will allow. 
         [0016]    Additional non-laser stacks can be placed between laser stacks or after laser-stacks to add required optics such as shutters or acousto-optics for controlling the laser beam intensities. 
         [0017]    The final output of the combined beams can be aligned into a fiber optic or other optical system, e.g., free space, which moves the beam to where it is used. A mechanical structure that can be attached to the stacks holds said optical system. 
         [0018]    The exemplary apparatus can comprise:
   One or more laser modules with different wavelength outputs.   Means for steering the beams with respect to each other for alignment purposes.   Means for combining the different beams into a single beam.   Means for controlling the intensity of individual beams either by turning them off and on or by attenuating the beams or both.   Means for maintaining the alignment between the combined beam and the device that uses the combined beam.   Means for managing heat if the environment and laser modules require it.   
 
         [0025]    An example system that would have three output wavelengths would have:
   A stack with a 488 nm laser module.   A stack with a 561 nm laser module.   A stack with a 640 nm laser module.   A poly-chromatic acousto-optical modulator for controlling the beam intensities.   A fiber output.   
 
         [0031]    In accordance with one exemplary embodiment, the connections made between stacks include:
   1) mechanical (stable, alignment maintaining);   2) optical (usually dichroics [polychromatic beamsplitters], but could be prisms, acousto-optical beamsplitters, grating, polarized beamsplitter); and   3) electrical (unless the electronics are external to the stacks).   
 
         [0035]    Optional connections include:
   1) Thermal (air cooling, liquid cooling, thermo-electric cooling)   2) Laser safety (interlock system, shutter(s))   3) Access for aligning and maintenance without separating stacks   4) Laser “control” means (turning on/off rapidly specific laser lines, power control of individual lines) include:
       1) AOTF=acousto-optical tunable filter (also called PCAOM=poly chromatic acousto optical modulator)   2) AOM=acousto optical modulator (usually one is needed for each laser line)   3) Shutter (one for each laser, or one master shutter usually for laser safety)   4) ND wheel=neutral density wheel (a mechanical way to control power intensity)   5) Direct laser electronic control (some lasers may be controlled directly via external voltages/signals or via computer commands-for example, many diode lasers can be controlled this way)   6) Pockel&#39;s cell (for very fast intensity control)   7) Rotating waveplate and analyzer (one for each line, or for all lines)   
       
 
         [0047]    Having a modular system such as this has the advantage that individual laser modules can be packaged into their stack and each such stack can be identical for the same model of laser. These pre-assembled stacks can then be combined in a relatively quick manner to form a complete laser system. The number of separate manufactured entities is now equal to the number of possible lasers instead of the number of possible laser combinations which is much greater. For example, if there are six appropriate lasers for a given field of interest, this invention would require the design and manufacture of six individual entities (plus those needed for intensity control) whereas a conventional means would require 62 possible entities. Another exemplary advantage is that a customer&#39;s laser system can be relatively easily upgraded by adding a laser. 
         [0048]    When designing such a modular system great care must be taken with the mechanical design. The stacks must be able to attach to each other rigidly. Beam alignment must be maintained in the particular environment where the device will be used. This environment can include vibrations, motion and thermal shifts. 
         [0049]    Because the system is designed to be flexible so that any number of beams can be added together, an appropriate way to combine the beams is to use long pass dichroics, such that the laser to be combined into the beam is reflected by the dichroic. All lasers of longer wavelength are transmitted. This requires the stacks be combined in order of wavelength. 
         [0050]    Aspects of the invention are thus directed toward a laser system. 
         [0051]    Still further aspects of the invention are directed toward a modular, scalable laser system. 
         [0052]    Even further aspects of the invention are directed toward a modular, scalable laser combiner system. 
         [0053]    Still further aspects of the invention are directed toward a control module working in cooperation with one or more laser modules. 
         [0054]    Even further aspects of the invention are directed toward a plurality of stackable laser modules controlled by a controlled module which outputs a combined laser beam. 
         [0055]    Still further aspects of the invention relate to mechanical alignment mechanism or a plurality of laser modules. 
         [0056]    Even further aspects of the invention relate to a mechanical alignment mechanism for a plurality of laser modules and a control module. 
         [0057]    Still further aspects of the invention relate to an apparatus for a combined laser system including:
   one or more laser modules with different wavelength outputs;   means for steering the beams with respect to each other for alignment purposes;   means for combining the different beams into a single beam;   means for controlling the intensity of individual beams either by turning them off and on or by attenuating the beams or both;   means for maintaining the alignment between the combined beam and the device that uses the combined beam;   means for managing heat if the environment and laser modules require it (each laser module can be packaged into a mechanical entity with its necessary optics and electronics. These entities can then be mechanically combined into a complete system with combined laser beams);   mechanical means for rigidly attaching these entities together.   
 
         [0065]    The aspect above, where the laser modules are solid-state laser modules. 
         [0066]    The aspect above, where the means for steering the beam consists of mirrors in mechanically adjustable mounts. 
         [0067]    The aspect above, where the means for controlling the intensities of individual lasers includes mechanical shutters for each laser. 
         [0068]    The aspect above, where the means for controlling intensities includes neutral density filter wheels. 
         [0069]    The aspect above, where a final mechanical shutter is used to block all outgoing laser beams. 
         [0070]    The aspect above where the means for controlling intensities includes acousto-optical devices for each individual laser. 
         [0071]    The aspect above, where the means for controlling intensities includes an acousto-optical device for multiple laser beams simultaneously. 
         [0072]    The aspect above, where the acousto-optical device is a poly-chromatic acousto-optic modulator. 
         [0073]    The aspect above, where the means for controlling intensities includes direct electronic control of the laser modules including electronic signaling or digital or serial commands via an interface. 
         [0074]    The aspect above, where the means for controlling intensities is packaged into a separate mechanical entity that can be introduced between or after the laser entities. 
         [0075]    The aspect above, where the output optics or fiber optic is mechanically attached to the end of the chain of laser entities. 
         [0076]    The aspect above, where the individual laser entities of the combined may be combined or removed without requiring re-alignment of the system. 
         [0077]    The aspect above, where the electrical signals required for the individual laser modules are routed through the system such that the entire system can be controlled with one interface (connector). 
         [0078]    The aspect above, where the electrical power required for the individual laser modules are routed through the system such that the entire system can be powered with one input. 
         [0079]    The aspect above, where an optical switching device is used to direct the output between 2 or more different output paths. 
         [0080]    The aspect above, where the switching device contains a moving mirror. 
         [0081]    These and other features and advantages of this invention are described and, or are apparent from, the following detailed description of the exemplary embodiment. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0082]    The exemplary embodiments of the invention will be described in detail, with reference to the following figures wherein: 
           [0083]      FIG. 1  illustrates an environmental perspective view and functional equivalent view of the exemplary laser system according to this invention; 
           [0084]      FIG. 2  illustrates an exemplary control module according to this invention; 
           [0085]      FIG. 3  illustrates an exemplary laser module according to this invention; 
           [0086]      FIG. 4  illustrates a perspective view of a bracket of one embodiments of the present invention; 
           [0087]      FIG. 5  illustrates an exploded view of the exemplary bracket according to this invention; 
           [0088]      FIG. 6  illustrates a partial perspective view of a base plate that receives a base portion and a head portion of the bracket according to an exemplary embodiment of this invention; 
           [0089]      FIG. 7  illustrates a perspective view of the base plate including interconnected bracket bases and heads according to this invention; 
           [0090]      FIG. 8  illustrates a perspective view of the base plate showing the brackets and plurality of mounts attached thereto according to an exemplary embodiment of this invention; 
           [0091]      FIG. 9  illustrates an exemplary component view of the control module according to this invention; and 
           [0092]      FIG. 10  illustrates another exemplary view of the laser system according to this invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0093]    The exemplary embodiments of this invention will be described in relation to lasers, laser systems, and associated components. However, it should be appreciated that, in general, known components will not be described in detail. For purposes of explanation, numerous details are set forth in order to provide a thorough understanding of the present invention. It should be appreciated however that the present invention may be practiced in a variety of ways beyond the specific details set forth herein. 
         [0094]    Furthermore, while the exemplary embodiments illustrated herein show various components of the system collocated, it is to be appreciated that various components of the system can be rearranged within the laser system such as in one or more of the described modules. Thus, it should be appreciated that the components of the system can be combined into one or more modules, or rearranged without necessarily changing the underlying functionality. Additionally, while the stack is shown in a vertical orientation, it need not be vertically oriented and could be horizontal or in general in any orientation. Furthermore, it should be appreciated that various illustrated links, connecting the elements can be wired or wireless links, or any combination thereof, or any other known or later developed element(s) that is capable of supplying and/or communicating data and/or power to and from the connected elements. The term “module” as used herein can refer to any known or later developed hardware, software, firmware, or combination thereof that is capable of performing the functionality associated with that element. The terms “determine,” “calculate” and “compute,” and variations thereof, as used herein are used interchangeably and include any type of methodology, process, mathematical operation or technique. 
         [0095]      FIG. 1  illustrates an exemplary embodiment of the laser system  1  according to this invention. The exemplary laser system  1  can be used for such applications as: SDC (Spinning Disk Confocal Imaging), confocal imaging, TIRF (Total Internal Reflection Fluorescence), FLIM (Fluorescence Lifetime Imaging Microscopy), photo activation, photo bleaching, photo ablation, photo wounding, FCS (Fluorescence Correlation Spectroscopy), cytometry, fluorescence imaging, or the like. 
         [0096]    In operation, a control module is mechanically associated with one or more laser modules as described in greater detail hereinafter. The outputs of the various laser modules are combined via a beam combiner(s)  380  as the laser is fed up through the stack of modules as illustrated in the inset of  FIG. 1 . 
         [0097]    For example, a first laser originates in stack  1  is combined with the laser from stack  2  with the cooperation of the beam splitter  380  and further combined with the lasers through stack N and output via the tunable filter  240  and laser safety master shutter  242  via the fiber mount  90 . The controller stack provides control of the various stacks as well as enables the stack to be daisy-chained together for power, control, and/or cooling. Additionally, status and/or control lights can be placed on each module within the stack to provide an indication of that particular module&#39;s operational state. 
         [0098]      FIG. 2  illustrates an exemplary control module  200  according to this invention. Control module  200  includes a power supply and controller  210 , USB hub  215 , cooling mechanism  220  (which may include one or more of a cooling plate or heat sink, fins, cooling tubes, a fan or the like and associated connectors), an Acousto-Optic Tunable Filter (AOTF) controller  230 , an acousto-optic tunable filter and optional shutter  240 , cooling connectors  250 , cooling lines  260 , a power connector  270 , power and control links  290  and pass-through cooling lines  280 . The control module  200  provides control of the output of the laser system  1  through varying one or more of the AOTF  240 , shutter and/or power to the various laser modules. The AOTF  240  acts as a shutter in the output laser beam path and is capable of being turned on and off very quickly. The power supply and controller  210  as well as the USB hub  215  allow control of the various laser modules within the laser system. Control commands from the power supply and controller  210  can be sent via link  290  to the various other modules that allow such things as turning on and off, varying of power levels, temperature and/or diagnostics monitoring, and the like. Intensities of the various lasers can be varied by, for example, power regulation, neutral density filter wheels and the like. Control information and various outputs, status indicators and the like can be forwarded to, for example, a display (not shown) and/or regulated through a software application having a graphical user interface. 
         [0099]    The cooling connectors  250  and associated lines  260  and  280  allow the laser system to be connected to, for example, an external cooling device, such as those used in personal computer applications. The cooling connectors in cooperation with the cooling lines  260  and  280  allow cooling, such as a cooling fluid, to be passed to a cooling plate  255 . The fluid is circulated through the cooling mechanism(s) and out to a pump and cooling mechanism (not shown) that cools the fluid. 
         [0100]    Each of the various modules can include a comparable cooling device  220  to help maintain thermal stability amongst the various modules. The coolant can be supplied serially from a first module to the other modules or supplied individually to each module. Furthermore, the cooling need not be done via fluid type coolant but could also be done with air cooling. 
         [0101]    The power connector  270  allows the control module to be supplied power from a power source. It should be appreciated however that a power connector  270  could be included on every module as well as associated on/off switches, power indicating lights, and the like. 
         [0102]      FIG. 3  illustrates an exemplary laser module  300 . The laser module  300  includes various components mounted on a base plate  14 . These components include a controller  310 , cooling device  320 , laser source  330 , mirror  360 , mirror adjustment screws  350 , a beam combiner  380 , combined laser  390 , beam combiner adjustment screws  370  and a cable/hose routing port  305  all enclosed in housing  340 . 
         [0103]    In operation, and at the direction of the controller  310 , a laser is emitted from the laser source  330 , reflected off of mirror  360  and optionally combined with one or more other upstream lasers at the beam combiner  380  to produce the combined laser  390 . 
         [0104]    The output of the laser source  330  can be aligned via one or more of the adjustment screws  350  and  370  to align the laser output from the laser module  300 . As with the control module  200 , the laser module  300  can include a cooling device  320 , such as a plate that receives cooling fluid from the coolant lines  280  that can optionally be routed to other modules within the laser system. Intensities of the various laser can be controlled electronically via control signals and/or modulated with an intensity module (that can be placed in a similar housing as the laser module and control modules) and interposed between, for example, two laser modules or between a laser module and a control module. Additionally, an optical switching device could be associated with the system to direct an output, e.g., the combined laser, between  2  or more different output paths, with the switching device optionally including a moving mirror. 
         [0105]    With reference to  FIGS. 4-10 , the construction of an exemplary embodiment of the modules will be discussed with reference to the following components: 
         [0000]    
       
         
               
               
               
             
           
               
                   
                   
               
             
             
               
                   
                 Base 
                 26 
               
               
                   
                 Base plate 
                 14 
               
               
                   
                 Bracket 
                 10 
               
               
                   
                 Post face 
                 54 
               
               
                   
                 Riser face 
                 58 
               
               
                   
                 Fiber holder 
                 90 
               
               
                   
                 Foot 
                 34 
               
               
                   
                 Head 
                 22 
               
               
                   
                 Laser generator 
                 18 
               
               
                   
                 Laser housing 
                 6 
               
               
                   
                 Laser mount 
                 74 
               
               
                   
                 Mirror mount 
                 78 
               
               
                   
                 Panel 
                 70 
               
               
                   
                 Post 
                 46 
               
               
                   
                 Recess 
                 66 
               
               
                   
                 Riser 
                 38 
               
               
                   
                 Set screw 
                 30 
               
               
                   
                 Stack 
                 2 
               
               
                   
                 Tapped hole 
                 42 
               
               
                   
                 Through hole 
                 62 
               
               
                   
                 Top plate 
                 86 
               
               
                   
                 Top surface 
                 50 
               
               
                   
                 Lower base plate 
                 82 
               
               
                   
                   
               
             
          
         
       
     
         [0106]    Referring now to  FIGS. 4-10 , a stack  2  of laser housings  6  is shown that are interconnected by brackets  10 . More specifically, the stack  2  is comprised of a plurality of vertically aligned laser housings  6 . Each laser housing  6  is comprised generally of a base plate  14  that is spaced from the base plate  14  of an adjacent laser housing by at least one bracket  10 . The brackets  10  are designed to secure adjacent laser housings  6  in such a way to allow for the optimum alignment and combination of beams produced by laser generators  18  located in each laser housing  6 . The brackets  10  are generally comprised of a riser  38  that is positioned between a head  22  and a base  26 . The brackets  10  facilitate interconnection of laser housings  6  and ensure proper alignment of each laser housing  6  in the stack  2 . 
         [0107]    Referring now to  FIGS. 4 and 5 , a bracket of one embodiment of the present invention is shown. The brackets  10  of embodiments of the present invention include the head  22  that is selectively interconnected to the base  26  via the riser  38 . The base  26  also includes a foot  34  for engagement onto the base plate  14 . The riser  38  and base  26  may be unitary or selectively interconnected to each other. The riser  38  includes a plurality of holes, such as a tapped holes  42 , that receive fasteners for interconnection of a panel that forms a side of the laser housing, which will be described in further detail below. The tapped holes  42  may be threaded, or, alternatively, be adapted to receive a threaded insert. The holes may also frictionally or otherwise engage a fastener. The head  22  of the bracket  10  also includes a post  46  extending therefrom. The post  46  and head  22  may be of unitary construction or be selectively interconnected to each other by at least one fastener, for example. The head  22  includes a top surface  50  for engagement onto a bottom surface of the base plate. The post  46  also includes a face  54  that engages a face  58  of the riser  38  to properly position the head  22  with respect to the base  26 . That is, the engagement of the post face  54  and the riser face  58  prevents substantial rotation of the head  22  relative to the base  26 . Preferably, a set screw  30  is placed through a through hole  62  of the base  26  and threaded into a tapped hole  42  in the post  46  to interconnect the head  22  to the base  26 . This interconnection scheme allows the head  22  be disassociated from the riser  38  from the outside of the laser housing. The base  26 , the riser  38  and the head  22  may each include a recess  66  for receipt of a panel  70  that defines a sidewall of the laser housing  6 , which will be described in further detail with respect to  FIG. 7 . However, one skilled in the art will appreciate that the panels may simply be interconnected via adhesives, hook and loop fasteners, magnets, etc., to an outer surface of the head  22  of the base  26  and/or the riser  38 . 
         [0108]    Referring additionally now to  FIGS. 6 and 7 , the base plate  14  is positioned between the base  26  and the head  22  wherein a fastener (not shown) secures the assembly via through holes  62  integrated into each of the bracket portions. It will be appreciated that the post  46  offsets the base plate  14  from a work surface and, thus, allows a user to lift the subassembly  11  comprised of heads  22 , bases  26  and risers  38 , and the base plate  14 . It is contemplated that a plurality of bases/heads/risers be added to the base plate  14  initially wherein laser mounts  74  and mirror mounts  78  are subsequently added to the base plate  14 . Finally, the laser  18  would be added to at least one base plate  14  of the stack which is designed to produce a laser beam that is coupled with other laser beams produced in other laser housings of the stack. 
         [0109]    Referring now to the figures, the stack  2  is defined by a plurality of vertically interconnected laser housings  6 . Initially, a lower base plate  82  would be positioned and a plurality of bracket bases with associated risers  38  interconnected thereto. As shown, the bases  26  positioned adjacent to the corners of the base plate  14 . One skilled in the art will appreciate, however, that the bases  26  of any shape are contemplated and that the brackets  10  do not necessarily have to be located at the corners of the base plate  14 . It is, however, desirous to locate the brackets  10  on an outside surface of the laser housing so that the set screws  30  are located in such a way to facilitate assembly of the stack  2 . A subassembly  11  with associated heads  22  on one side of the base plate  14  and bracket bases  26  on another side, of the base plate  14 , would then be positioned atop the risers  38  associated with the lower base plate  82 . The heads  22  of the subassembly  11  are then interconnected to the risers  38  associated with the lower base plate  82  as shown in  FIGS. 4 and 5 . A plurality of set screws  30  would then be used to firmly interconnect the heads, via the posts, to the risers  38 . As shown, a hex headed set screw is provided. One skilled in the art will appreciate that other types of fasteners may be used equally well. Additional subassemblies  11  are added as needed to form the completed stack  2 . Finally, a plurality of panels  70  are interconnected to the brackets  10  by way of fasteners (not shown) that engage the tapped holes provided in the bracket  10 . Preferably, the panels  70  are recessed into the bracket  10  such that they are flush with a top plate  86  and base plates  14 ,  82  of each laser housing  6 . The panels  70  may be interconnected alternatively to the bracket  10  via adhesives, hook and loop fasteners, magnets or any other selective interconnection technique. To complete the assembly of fiber holder  90  may be interconnected to the top plate  86 . One skilled in the art will appreciate that the brackets  10  may also include lifting devices associated therewith to help position the completed stack. Likewise, other means of securing the head relative to the riser could be used such as a post and receiving aperture, kinematic mounts, direct fastening of the stacks together, the use of a matched base and top plates and interconnects that allow the stacks to be positioned horizontally. 
         [0110]    Referring again to  FIGS. 4 and 5 , the brackets  10  of embodiments of the present invention are made of machined metal. One skilled in the art, however, will appreciate that other materials, such as composites may be employed without departing from the scope of the invention. It is desirous to provide a bracket  10  that is less prone to thermal expansions, thereby reducing the risk of laser and/or mirror misalignments during heating and cooling of the stack  2 . The head  22  portion of the bracket  10  as described above, employs the post  46  interconnected thereto. Preferably, a series of set screws  30  are used to interconnect the head  22  to the post  46 . One skilled in the art will appreciate that the head  22 /post  46  may be a unitary component. Similarly, the riser  38  may be interconnected to the base  26  by way of a plurality of set screws. These components may also be formed of one-piece construction. The riser  38  may be of any length and of any shape. Preferably, the interconnected post  46  and riser  38  have a prismatic shape to facilitate angular alignments of adjacent laser housings  6 . 
         [0111]    The exemplary techniques illustrated herein are not limited to the specifically illustrated embodiments but can also be utilized with the other exemplary embodiments and each described feature is individually and separately claimable. 
         [0112]    The systems of this invention can cooperate and interface with a special purpose computer, a programmed microprocessor or microcontroller and peripheral integrated circuit element(s), an ASIC or other integrated circuit, a digital signal processor, a hard-wired electronic or logic circuit such as discrete element circuit, a programmable logic device such as PLD, PLA, FPGA, PAL, any comparable means, or the like. 
         [0113]    Furthermore, the disclosed control methods and graphical user interfaces may be readily implemented in software using object or object-oriented software development environments that provide portable source code that can be used on a variety of computer or workstation platforms. Alternatively, the disclosed control methods may be implemented partially or fully in hardware using standard logic circuits or VLSI design. Whether software or hardware is used to implement the systems in accordance with this invention is dependent on the speed and/or efficiency requirements of the system, the particular function, and the particular software or hardware systems or microprocessor or microcomputer systems being utilized. 
         [0114]    It is therefore apparent that there has been provided, in accordance with the present invention, a laser system. While this invention has been described in conjunction with a number of embodiments, it is evident that many alternatives, modifications and variations would be or are apparent to those of ordinary skill in the applicable arts. Accordingly, it is intended to embrace all such alternatives, modifications, equivalents and variations that are within the spirit and scope of this invention.