Laser cutting of stents and other medical devices

Abstract

A desired pattern may be cut into a stent preform by impinging a laser beam onto the stent preform. The laser beam is formed using a laser system comprising a resonator cavity for resonating laser radiation, a gain medium contained in the resonator cavity, a pump for periodically pumping the gain medium and an electro-optical modulator in communication with the resonator cavity. The laser system produces a radiation pulse for each pump period. Each radiation pulse is conditioned by suppressing at least a portion of the pulse. The pulse may also be modulated with an electro-optical modulator to produce a pulse train of ordered pulses of radiation. Each pulse train is output from the optical cavity as an output laser beam which is directed at the stent preform to cut a desired pattern in the stent preform.

1 . A method of processing a stent preform comprising the steps of: 
 providing a stent preform;    providing a laser system comprising: 
 a) a resonator cavity for resonating laser radiation  
 b) a gain medium contained in the resonator cavity  
 c) a pump for periodically pumping the gain medium, the laser system producing a radiation pulse for each pump period;  
 d) conditioning the radiation pulse by suppressing a portion of, but not the entirety of the radiation pulse to produce conditioned radiation;  
 e) outputting the conditioned radiation in the form of a laser beam  
 f) directing the laser beam at the stent preform; and  
 g) impinging the laser beam onto the stent preform to cut a desired pattern in the stent preform.  
   
     
     
         2 . The method of  claim 1  wherein the stent preform is a tube.  
     
     
         3 . The method of  claim 2  wherein the tube is made of Nitinol.  
     
     
         4 . The method of  claim 2  wherein the tube is made of at least one polymeric material.  
     
     
         5 . The method of  claim 1  wherein the stent preform is a sheet of material, the method further comprising the step of forming the sheet into a tube subsequent to the impinging step.  
     
     
         6 . The method of  claim 2  wherein the tube is made of stainless steel.  
     
     
         7 . The method of  claim 1  wherein only the beginning of the pulse is suppressed.  
     
     
         8 . The method of  claim 1  wherein only the beginning of the pulse and the end of the pulse are suppressed, a portion of the pulse between the beginning and the end not being suppressed.  
     
     
         9 . The method of  claim 1  wherein only the end of the pulse is suppressed.  
     
     
         10 . The method of  claim 9  wherein the laser beam is entrained in a column of water prior to being impinged against the stent perform.  
     
     
         11 . The method of  claim 1  wherein the conditioning step further comprises conditioning each radiation pulse to produce a pulse train of ordered pulses of radiation for each radiation pulse.  
     
     
         12 . The method of  claim 11  wherein the stent preform is formed of Nitinol.  
     
     
         13 . The method of  claim 1  wherein during the impinging step the stent preform is moved relative to the laser beam.  
     
     
         14 . The method of  claim 11  wherein during the impinging step the stent preform is moved relative to the laser beam.  
     
     
         15 . A method of processing a medical device preform comprising the steps of: 
 providing a medical device preform;    providing a laser system comprising: 
 a) a resonator cavity for resonating laser radiation  
 b) a gain medium contained in the resonator cavity  
 c) a pump for periodically pumping the gain medium, the laser system producing a radiation pulse for each pump period;  
 d) conditioning the radiation pulse by suppressing a portion of, but not the entirety of the radiation pulse to produce conditioned radiation;  
 e) outputting the conditioned radiation in the form of a laser beam  
 f) directing the laser beam at the medical device preform; and  
 g) impinging the laser beam onto the medical device preform to modify the surface of the medical device preform.  
   
     
     
         16 . The method of  claim 15  wherein the medical device preform is a stent preform.  
     
     
         17 . The method of  claim 16  wherein the stent preform is tubular.  
     
     
         18 . The method of  claim 17  wherein during the impinging step, a desired pattern is cut into the stent preform.  
     
     
         19 . The method of  claim 15  wherein only the beginning of the pulse is suppressed.  
     
     
         20 . The method of  claim 15  wherein only the beginning of the pulse and the end of the pulse are suppressed, a portion of the pulse between the beginning and the end not being suppressed.  
     
     
         21 . The method of  claim 15  wherein only the end of the pulse is suppressed.  
     
     
         22 . The method of  claim 15  wherein the conditioning step further comprises conditioning each radiation pulse to produce a pulse train of ordered pulses of radiation for each radiation pulse.  
     
     
         23 . The method of  claim 18  wherein the conditioning step further comprises conditioning each radiation pulse to produce a pulse train of ordered pulses of radiation for each radiation pulse.