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PubMed · 15704158

Thin cylindrical diffusers in multimode Ge-doped silica fibers.

Lothar Lilge·Leonid Vesselov·William Whittington
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Abstract

BACKGROUND AND OBJECTIVES: Cylindrical fiber diffusers are common tools in photodynamic therapy (PDT). However, large outer diameter and short length limit the indications to which they can be applied. Here a diffuser with an outer diameter of 250 microm and an active length exceeding 5 cm was developed. STUDY DESIGN/MATERIALS AND METHODS: Diffusers based on photosensitive quartz optical fibers with a cladding diameter of 140 microm were developed using a structured beam from an excimer laser. A complete set of photometric characteristics, including longitudinal, polar, and azimuth radiance emission diagrams were collected. RESULTS AND CONCLUSIONS: The longitudinal radiance emission is homogenous to within +/-10%. The ability to create custom designed longitudinal emission profiles was demonstrated. The variations of the polar and azimuth radiance emission diagrams were within +/- 15% from an ideal Lambertian emitter. The polar uniformity can be improved with a slight increase of the outer diameter using a diffusing recoating compound. The residual light leakage at the distal end of the fiber diffuser was suppressed to 2%. The minimal bending radius after recoating is approximately 5 mm. Maximum power distribution is > 0.5 W cm(-1).

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Equipment DesignFiber Optic TechnologyGermaniumHumansMaterials TestingOptical FibersPhotochemotherapyJournal ArticleResearch Support, N.I.H., ExtramuralResearch Support, Non-U.S. Gov'tResearch Support, U.S. Gov't, P.H.S.

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Lothar Lilge, Leonid Vesselov, William Whittington. 2005. Thin cylindrical diffusers in multimode Ge-doped silica fibers.. https://doi.org/10.1002/lsm.20150

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