title: The effect of optical design on micromanipulator spot size using CO2 laser irradiation.
abstract: OBJECTIVE
  The study goal was to compare the laser spot size created using reflective and refractive micromanipulators with a CO(2) laser and to determine the sensitivity of spot size to laser power.
  
  
  METHODS
  A CO(2) laser and operating microscope (400-mm focal length) was coupled to either a reflective (Cassegrain-like) or refractive micromanipulator. Laser spot size was determined by measuring the region of ablation created by laser irradiation of wood (dry tongue depressors), exposed photographic film, and agar gel using optical micrometry. Laser power varied from 0.5 to 20 W with pulse durations of 0.1 and 0.5 second.
  
  
  RESULTS
  The reflective micromanipulator demonstrated overall smaller spot sizes for a given laser power and lower incremental change in spot size with increasing power. The reflective design demonstrated less sensitivity to increases in laser power.
  
  
  CONCLUSIONS
  Micromanipulator optical design can result in significant differences in laser spot size. The reflective device used in this study demonstrated less sensitivity to increasing laser power.
authors.affiliation: School of Medicine, University of Texas Health Science Center at San Antonio, USA.
authors.forename: Kenneth K H
authors.initials: KK
authors.lastname: Chao
authors.forename: Eric
authors.initials: E
authors.lastname: Cheung
authors.forename: William B
authors.initials: WB
authors.lastname: Armstrong
authors.forename: Brian J F
authors.initials: BJ
authors.lastname: Wong
mesh_terms: D000465:Algorithms; D002245:Carbon Dioxide; D004867:Equipment Design; D004869:Equipment Safety; D005336:Fiber Optic Technology / Q000295:instrumentation; D006801:Humans; D053685:Laser Therapy / Q000295:instrumentation*; D007834:Lasers / Q000145:classification; D007909:Lenses; D008846:Micromanipulation; D008866:Microsurgery / Q000295:instrumentation*; D008961:Models, Structural; D012680:Sensitivity and Specificity; D013499:Surface Properties
chemical_list: D002245:Carbon Dioxide