Scanning miniature optical probes with optical distortion correction and rotational control

Abstract

Optical probes having a diameter less than substantially 500 μm for use in scanning light from a long, highly flexible fiber to a sample. In one embodiment the probe includes a viscous damping fluid suitable to prevent non-uniform rotational distortion (NURD).

1 - 27 . (canceled)  
     
     
         28 . An optical probe comprising: 
 a sheath; 
 a rotatable optical transmission system positioned within the sheath, the optical transmission system comprising  
 a transmission fiber, the transmission fiber capable of winding in response to rotation of the transmission system; and  
   a viscous damping fluid disposed within the sheath,    the viscous fluid chosen to reduce rotational speed variations at least partially induced by winding the transmission fiber.    
     
     
         29 . The optical probe of  claim 28  wherein the optical transmission system is less than about 300 μm in diameter.  
     
     
         30 . The optical probe of  claim 29  wherein the optical transmission system comprises a focusing element optically coupled to a beam director.  
     
     
         31 . The optical probe of  claim 28  wherein the optical transmission system creates: 
 an exit beam waist less than 100 μm in radius with a working distance ranging from about 0 to about ten millimeters, and a depth-of-field to about 10 mm.    
     
     
         32 . The optical probe of  claim 31  wherein the working distance and depth of field are applicable to either air-based or fluid based imaging conditions.  
     
     
         33 . The optical probe of  claim 28  wherein the sheath is less than about 500 μm in diameter.  
     
     
         34 . The optical probe of  claim 28  wherein the viscous damping fluid is contained at least within a distal portion of the sheath.  
     
     
         35 . The optical probe of  claim 30  wherein the transmission fiber is slidably rotatable within the sheath.  
     
     
         36 . The optical probe of  claim 30  wherein the focusing element and the beam director comprise 
 a first segment of coreless silica fiber attached to the transmission fiber, a graded index fiber, attached to a second segment of coreless fiber, wherein the second segment of coreless fiber has one or more angled facets to form the beam director.    
     
     
         37 . The optical probe of  claim 30  wherein the focusing element and beam director comprise: 
 a transmission fiber attached to a piece of graded index fiber having an end face,    the transmission fiber's working aperture and index profile designed to produce a beam waist of less than 100 μm in radius at a working distance measured from the end face of up to ten millimeters in either air or fluid; and    a faceted piece of coreless fiber attached to the graded index fiber.    
     
     
         38 . The optical probe of  claim 36  wherein the angled coreless fiber is reflectively coated on one angled facet.  
     
     
         39 . The optical probe of  claim 36  wherein the angled coreless fiber has a first facet angle such that the beam director directs the beam using total internal reflection.  
     
     
         40 . The optical probe of  claim 30  wherein the beam director comprises two facets, a first facet acting as a reflector and a second facet acting as a transmissive element, wherein an angle of residual back reflected light arising from the second facet and re-reflecting from the first facet through the focusing element exceeds an acceptance angle of the transmission fiber.  
     
     
         41 . The optical probe of  claim 28  wherein the sheath comprises a plurality of regions, each region having a predetermined length and containing a fluid with a predetermined kinematic viscosity index.  
     
     
         42 . The optical probe of  claim 28  further comprising a lumen for providing catheter flushes.  
     
     
         43 . The optical probe of  claim 42  wherein catheter flushes are maintained at body temperature to minimize temperature-induced viscosity changes at a distal tip of the catheter.  
     
     
         44 . An optical probe comprising: 
 a first sheath defining a bore;    a viscous damping fluid, having an index of refraction, in fluid communication with the first sheath; and    a rotatable optical fiber located within the first sheath such that winding and unwinding of the rotatable optical fiber is regulated by the viscous damping fluid.    
     
     
         45 . The optical probe of  claim 44  further comprising an optical transmission system, 
 the optical transmission system comprising    the first sheath, a beam director located within the bore of the first sheath;    a focusing element located within the bore of the first sheath and optically coupled to the beam director located within the bore of the first sheath; and    a second sheath defining a bore, the first sheath located within the bore of the second sheath.    
     
     
         46 . The optical probe of  claim 45  wherein the optical transmission system is less than substantially 300 μm in diameter.  
     
     
         47 . The optical probe of  claim 45  wherein the optical transmission system creates an exit beam waist less than 100 μm in radius with a working distance ranging from 0 to ten millimeters, and a depth-of-field up to twenty millimeters.  
     
     
         48 . The optical probe of  claim 45  wherein the second sheath is less than substantially 500 μm in diameter.  
     
     
         49 . The optical probe of  claim 45  wherein the focusing element comprises a coreless fiber with a radiused tip.  
     
     
         50 . The optical probe of  claim 45  wherein the index of refraction of the fluid is chosen to substantially remove optical cylindrical distortion of the beam propagation through the second sheath.  
     
     
         51 . The optical probe of  claim 45  further comprising a lumen for providing catheter flushes.  
     
     
         52 . The optical probe of  claim 51  wherein catheter flushes are maintained at body temperature to minimize temperature-induced viscosity changes at the distal tip of the catheter.  
     
     
         53 . A viscous damping fluid adapted for use in an optical probe, 
 the fluid having an index of refraction and a viscosity, wherein the viscosity and the index of refraction are selected to reduce cylindrical optical distortion and non-uniform rotational distortion.    
     
     
         54 . The fluid of  claim 53  wherein the viscosity has a kinematic viscosity index that ranges from about 500 to about 20,000.  
     
     
         55 . The fluid of  claim 53  wherein the fluid has a kinematic viscosity index that ranges from about 500 to about 20,000.  
     
     
         56 . The fluid of  claim 53  wherein the fluid has an optical index of refraction that ranges from about 1.32 to about 1.65.  
     
     
         57 . The fluid of  claim 53  wherein the fluid has a temperature dependent viscosity.  
     
     
         58 . The fluid of  claim 53  wherein the fluid is substantially optically transmissive at wavelengths ranging from about 800 nm to about 2 um.