for each of the embodiments described below , a versatile process is employed to deposit stoichiometric films which range in thickness from a few angstroms to a few microns . since both the laser system and the atmosphere in which the process is carried out are a function of the material to be deposited , these parameters are altered accordingly . for the laser system , the determinative factor in practicing the claimed invention is the use of a laser that produces enough energy to evaporate a target material within the duration of a single pulse , regardless of the source of the laser energy . a selected target material may require the use of , for example , an excimer laser , lasing in the ultra - violet range , or a yag - type laser , lasing in the infrared region , to produce enough energy to evaporate the material . therefore , a high power pulsed laser encompasses any pulsed laser system that can supply enough energy , typically 1 - 2 j / cm 2 , to the surface of the target , to evaporate the material . while the present invention can also be practiced with a laser that produces a continuous beam that is incident on the target , i . e ., an ar laser , practical considerations such as process efficiency have made pulsed laser systems preferred over an equilibrium - type process utilizing continuous energy . in addition to the laser employed , the atmosphere in which the deposition process occurs can be easily altered depending on the material to be deposited . for example , once the vacuum chamber is evacuated to a desired pressure , i . e ., 10 − 6 - 10 − 7 torr , it can be backfilled to the milli - torr range with an appropriate atmosphere . the atmosphere can vary from an oxygen atmosphere that aids in the deposition of a ceramic superconductor to a reducing atmosphere that aids in the deposition of a nitride material . an object of this invention thus relates to a method for depositing materials on the inner walls of a pipe or rigid rod . in this embodiment , a high power pulsed laser beam ( b , fig1 ) passes through a positive lens ( l ), which concentrates the light onto the surface of the target material ( t ) to be ablated by the laser . as most depositions must take place either in vacuum or in a low - pressure atmosphere other than air , the process will take place inside an appropriate chamber , and a window ( vw ) must be provided for passage of the light beam . the target is placed within the pipe ( p ) to be coated , as shown in fig1 and slanted so that the beam will intercept it at some convenient angle ( 45 °, for example ). the target is located at a relatively short distance from the focal plane of lens ( l ), so that the light intensity at the target is sufficient to ablate and evaporate material , and is joined to a shaft whose axis coincides with the pipe axis of symmetry . the plume ( pl ) of evaporated material reaches the pipe inner wall at an angle , corresponding to the target inclination , as shown in fig1 . for small - diameter pipes it may be more convenient in some cases to keep the target perpendicular or near - perpendicular to the beam . in order to coat the inner wall of the pipe uniformly , relative motions , both angular and longitudinal , are required between the pipe and the ablation spot . angular motion may be provided by rotating either the pipe or the shaft ( s ), or both in opposite directions , around their common axis of symmetry . linear motion may be provided by shifting either the pipe or the target - shaft arrangement along the axis of symmetry . again , a combination of both of these motions in opposite directions may be employed . if target motion along the axis is used , it will be required to maintain the laser spot geometry at target ( t ) constant , in order to avoid changes in deposition yield . this can be easily achieved in two ways : ( 1 ) by shifting lens ( l ) along the axis simultaneously with , and by the same distance as , the target - shaft assembly ; or ( 2 ) by employing a multiple - lens setup , such as the one indicated in fig2 so that the size of the laser spot at target ( t ) can be adjusted for a large range of motion of target ( t ) by a small motion of one of the lenses in the setup , for example , l 2 in fig2 . the first way is more direct , but limited in applicability because the fixed focal length of the single lens will confine the length of pipe which can be coated to a value substantially smaller than this focal length . the largest separation allowable between lens ( l ) and window ( w ) ( fig1 ) is limited by the damage threshold intensity for the window . motion of the target - shaft assembly is effected by means of a rotary / linear vacuum feedthrough ( ft in fig3 ) connecting the shaft ( s ) to motion equipment external to the chamber , through the chamber wall ( cw ). either of the systems described above can be readily placed in a vacuum chamber with a cylindrical configuration . some of the materials to be deposited on the pipe inner walls require specific substrate temperatures , often much higher than room temperature , in order for desired phases to form . this can be conveniently provided , without necessarily contacting the pipe , by a coaxial heater assembly ( h in fig3 ) which can heat the pipe ( p ), for example , by radiation from toroidal lamps , or by inductively coupling rf energy to the pipe . another possible configuration ( fig4 ) is one in which the cylindrical chamber wall is constituted by the pipe to be coated itself . in this case , the lids of the chamber will be the window and target - shaft - feedthrough assemblies . these are attached to the pipe by suitable vacuum seals ( j in fig4 ). all required service ports , such as for pumping , gas flow , pressure gauges , etc ., can be located in these two attachments . the arrangement just described is convenient if the operation of coating pipes of the same diameter must be performed repeatedly , as this is the most compact apparatus possible . also , heating of the pipe and monitoring of its temperature can be accomplished very easily in the latter case , as the outer pipe wall is available externally . a second object of this invention relates to a method for depositing materials on the inner walls of a pipe in a symmetric configuration . in this embodiment , the laser beam is shaped by suitable optics into a conic beam incident onto a conic target . surface which is subsequently ablated by the laser . more specifically , an axially symmetric laser beam ( b , fig5 ) passes through a negative conical lens ( a ), also known as an axicon , along its axis . as shown in fig5 this lens shapes the beam into a diverging conical fan which is then intercepted by a spherical converging lens ( l ). this second lens changes the fan direction and concentrates the light into a circle which would coincide with the focal plane of lens ( l ). the surface of the target material ( t ) to be ablated by the laser is shaped as a cone or truncated cone , as shown , so that the beam will intercept it at some convenient angle ( 45 °, for example ). the target is held by a shaft ( s ) and located at a distance from the focal plane of lens ( l ), so that the laser beam “ footprint ” at the target surface is actually an annular ring . the high intensity pulsed light at target ( t ) produces a plume ( pl ) of evaporate material . as the pld process is normally conducted in a vacuum chamber , and the optics are usually placed outside the chamber in order to avoid coating them , an optical window ( w ) allowing the passage of laser light into the chamber ambient will be required . the distance between the target ( t ) and the focusing lens ( l ) is adjusted so that the desired light intensity at the target surface is obtained . the symmetry axes of the target and both lenses are collinear . with this geometry , the laser - generated plume will have a conical shape , and will be directed away from the common symmetry axis of the setup . the pipe or tube to be coated ( p ) should be located with its longitudinal axis coincident with this symmetry axis ( fig5 ). clearly , from the symmetry , the rate of evaporate incidence on the pipe wall is the same for every direction in the cone generated by the plume . this will ensure angular uniformity of coverage for the pipe being coated . in order to coat a length of the pipe ( p ) it is sufficient to cause relative motion between the pipe and the shaft ( s ) along their common axis . the speed of this motion will determine , for fixed target ablation conditions at a given geometry , the thickness of the resulting film . linear motion may be provided by shifting either the pipe or the target shaft arrangement along the axis of symmetry . a combination of both of these motions in opposite directions may also be employed . if target motion along the axis is used , it will be required to maintain the laser “ footprint ” geometry at ( t ) constant , in order to avoid changes in deposition yield . this can be achieved by coordinated motion of the a - l lens combination . the length of rigid rod or pipe which can be coated in this setup is limited by the distance between the window ( w ) and the target ( t ). this distance depends in turn on the detail of the focal length of lens ( l ) and the apex angle of the conical lens ( a ). it is possible to select these parameters to accommodate a pipe length of tens of centimeters by using a long focal length for lens ( l ). it can be more convenient , however , to modify the setup to include a second axicon ( a 2 in fig6 ). this second conic lens has the same ( or nearly the same ) apex angle as a , but is positive instead of negative . its diameter also needs to be larger in order to intercept the complete light fan generated by lens ( a ). with the configuration shown in fig6 the focal length of lens ( l ) can be chosen to be longer , as its function is then just to focus the light beam . the distance between the two axicons a and a 2 in the setup of fig6 will determine the radius of the ray fan intercepted by lens ( l ). if the lens ( l ) in fig6 is replaced by a combination of spherical lenses so that the focal length of the combination is variable , an additional flexibility is introduced , with the advantage of allowing a relatively short motion of one lens to compensate for much longer displacements of the target - shaft assembly . the second setup ( fig6 ) makes it easier to modify the exact radius of the laser beam footprint on the target . slight modification of this radius is convenient in order to use more effectively the target area as the coating process proceeds and avoid undesirable plume changes due to crater formation . simultaneous adjustment of the position of lens ( l ) ( or its focal length , if it is a multiple - element lens ) will be required in this case in order to maintain a constant deposition rate at the surface being coated . the setup of fig6 also provides the possibility of using a smaller cone angle for the conical beam issuing after lens ( l ). this is advantageous in that it allows pipes with larger aspect ratios ( length to diameter ) to be coated . motion of the target - shaft assembly , if required , can be effected by means of a linear vacuum feedthrough ( ft in fig7 ) connecting the shaft ( s ) to motion equipment external to the chamber through the chamber wall ( cw ). rotary motion of the target is not necessary , but can be provided if a linear / rotary feedthrough is used instead of a linear one . either of the systems described above can be readily placed in a vacuum chamber with a cylindrical configuration . some of the materials to be deposited on the pipe inner walls require specific substrate temperatures , often much higher than room temperature , in order for desired phased to form . this can be conveniently provided , without necessarily contacting the pipe , by a coaxial heater assembly ( h in fig7 ) which can heat the pipe ( p ), for example , by radiation from toroidal lamps , or by inductively coupling rf energy to the pipe . the pipe can be inserted and extracted from the vacuum chamber by means of a differentially pumped secondary chamber , in order to accelerate processing times . another possible configuration ( fig8 ) is one in which the cylindrical chamber wall is constituted by the pipe to be coated itself . in this case , the lids of the chamber will be the window and target - shaft - feed through assemblies . these are attached to the pipe by suitable vacuum seals ( j in fig8 ). all required service ports , such as for pumping , gas flow , pressure gauges , etc ., can be located in these two attachments . this arrangement is convenient if the operation of coating pipes of the same diameter must be performed repeatedly , as this is the most compact apparatus possible . also , heating of the pipe and monitoring of its temperature can be accomplished very easily in the latter case , as the outer pipe wall is available externally . another object of this invention relates to a method for depositing materials on the outer walls of a wire or pipe . in this embodiment , an axially symmetric laser beam ( b ) passes through a negative conical lens ( a ), also known as an axicon , along its axis . as shown in fig9 this lens shapes the beam into a diverging conical fan which is then intercepted by a spherical converging lens ( l ). this second lens changes the fan direction and concentrates the light into a circle which would coincide with the focal plane of lens ( l ). the surface of the target material ( t ) to be ablated by the laser is shaped into a conic section , as shown , so that the beam will intercept it at some convenient angle ( 45 °, for example ). the target is located at a distance from the focal plane of lens ( l ), so that the laser beam “ footprint ” at the target surface is actually an annular ring . the high intensity pulsed light at t produces a plume ( p ) of evaporate material . as the pld process is normally conducted in a vacuum chamber , and the focusing optics are usually placed outside the chamber in order to avoid coating them , an optical window ( w ) allowing the passing of the laser light into the chamber ambient will be required . the distance between the target ( t ) and the focusing lens ( l ) is adjusted so that the desired light intensity at the target surface is obtained . the symmetry axes of the target and both lenses are collinear . with this geometry , the laser - generated plume will have a conical shape , pointed towards the common symmetry axis of the setup . the wire , rod , or pipe to be coated ( work piece c ) should be located with its longitudinal axis coincident with this symmetry axis . clearly , from the symmetry , the rate of evaporate incidence from the target towards the symmetry axis is substantially the same for every direction . this will ensure angular uniformity of coverage for the cylindrical object being coated . in order to coat a length of the object ( c ) it is sufficient to move it longitudinally along the symmetry axis at a constant rate . the speed of this motion will determine , for fixed target ablation conditions at a given geometry , the thickness of the resulting film . the length of rigid rod or pipe which can be coated in this setup is limited by the distance between the window ( w ) and the target ( t ). this distance depends in turn on the detail of the focal length of lens ( l ) and the apex angle of the conical len ( a ). it is possible to select these parameters to accommodate a rod length of tens of centimeters by using a long focal length for lens ( l ). it can be more convenient , however , to modify the setup ( fig1 ) to include a second axicon ( a 2 ). this second conic lens has the same ( or nearly the same ) apex angle as a , but is positive instead of negative . its diameter also needs to be larger in order to intercept the complete light fan generated by lens ( a ). with the configuration shown in fig1 the focal length of lens ( l ) can be chosen to be longer , as its function is then just to focus the light beam . the distance ( d ) between the two axicons a and a 2 in the setup of fig1 will determine the radius of the ray fan intercepted by lens ( l ). this second setup makes it easier to modify the exact radius of the laser beam footprint on the target . slight modification of this radius is convenient in order to use more effectively the target area as the coating process proceeds and avoid undesirable plume changes due to crater formation . simultaneous adjustment of the position of lens ( l ) will be required in this case in order to maintain a constant light intensity at the target surface . changes in the laser beam footprint radius at the target will cause changes in the deposition rate at the surface being coated . if the deposition rates cannot be tolerated , they can be compensated in the process by changing the light intensity or the speed of motion of the work piece . if the work piece to be coated is a flexible wire , a convenient setup is shown in fig1 that allows coating a long length of the wire by continuously supplying it laterally from a reel . a set of pulleys or channels guide the wire under tension through the optical axis of the coating system . the first pulley ( p 1 ) can be conveniently kept inside the “ dark zone ” between ( l ) and ( t ), so it does not intercept any light . the wire itself being fed laterally , and the pulley axis do intercept the light beam , but this should have only a small effect on the uniformity of the resulting coating . if it is important to avoid excessive bending of the wire once the film has been deposited ( in order to avoid delamination , for example ) the take - up pulley or bobbin can be specified to have a sufficiently large diameter . another possibility is to pass the wire straight out of the deposition chamber through a set of narrow openings with a differentially pumped intermediate volume . once outside the chamber the wire can be further processed or cut to desired lengths while kept straight . as some of the materials prepared by pld require high substrate temperatures to achieve a high quality film , it will be necessary in some cases to heat the wire or rod being coated . this can be done in several convenient ways due to the cylindrical geometry of the setup ; for example , by means of an annular heating filament or lamp ( h ) located near ( or right behind ) the target ( t ) ( fig1 ). if a wire to be coated is electrically conducting , a current may instead be passed trough it between the feed pulley ( p 1 ) and the take - up pulley ( p 2 ), thus causing the wire to be heated to a predetermined temperature at the deposition zone . the cylindrical geometry allows also for convenient processing after the film has been deposited . for example , other coatings may be deposited by other methods or by pld . an accessible manner of depositing a second coating by pld is by using a similar arrangement from the other side , as shown in fig1 . in this case , the space between the two targets ( t 1 , t 2 ) may be used to provide a drive mechanism to move the wire , rod or pipe work piece . it is understood that various other modifications will be apparent to and can be readily made by those skilled in the art without departing from the scope or spirit of the invention . accordingly , it is not intended that the scope of the following claims be limited to the forgoing description . rather , the claims should be construed as also encompassing features that would be treated as equivalents thereof by those skilled in the art to which this invention pertains .