title: Side-firing sealing caps for hollow optical fibers.
abstract: OBJECTIVE
  Hollow optical fibers are useful for delivery of high-energy infrared laser beam such as Er:YAG lasers. We propose side-firing optics for hollow optical fibers for laser endoscopic applications mainly in oto-rhino-laryngology and urology.
  
  
  METHODS
  To produce a circular beam, cone-shaped caps are designed and caps with slanted end are proposed for producing a spot beam in side direction. Both types of caps are fabricated by fusing and polished Pyrex and silica glass tubes.
  
  
  RESULTS
  For the both of the cone-shaped and slanted-end caps effectively deflect laser beam as designed and these caps show high durability for Er:YAG laser light with pulse energy higher than 100 mJ.
  
  
  CONCLUSIONS
  By choosing the proper shape of the cap ends, these caps deflect an input laser beam to a preferred direction at low insertion losses. By using these side-firing optics, one can easily irradiate the inside of tubular organs.
authors.affiliation: Department of Electrical Communications, Tohoku University, 05 Aoba, Aramaki, Sendai 980-8579, Japan.
authors.forename: Tomonori
authors.initials: T
authors.lastname: Watanabe
authors.forename: Yuji
authors.initials: Y
authors.lastname: Matsuura
mesh_terms: D004724:Endoscopy; D004867:Equipment Design; D004871:Erbium; D005336:Fiber Optic Technology; D053685:Laser Therapy / Q000295:instrumentation*; D055100:Optical Fibers; D013517:Otorhinolaryngologic Surgical Procedures / Q000295:instrumentation*; D013520:Urologic Surgical Procedures / Q000295:instrumentation*
chemical_list: D004871:Erbium