Pal, Debasis and Das Chowdhury, Sourav and Dhar, Anirban and Saraf, Siddharth and Maiti, Krishnendu and Pal, Dilip Kumar and Sen, Ranjan and Pal, Atasi (2019) Ex vivo testing of air-cooled CW/modulated 30 W thulium fiber laser for lithotripsy. Applied Optics, 58 (25). pp. 6720-6724. ISSN 0003-6935

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A diode-pumped, air-cooled, all-fiber, quasi-continuous-wave thulium laser at an operating wavelength of 1.94 mu m has been designed to study the performance of the laser parameter on the rate of fragmentation and its dependence on stone composition, fragmented particle size, as well as the retropulsion effect. The optimized laser cavity with an active fiber core/cladding diameter of 10/130 pm under a counter-propagating pump provides a stable laser power of 30 W at a slope efficiency of 50% and wall plug efficiency of 17%. The rate of fragmentation along with the retropulsion effect has been studied with human calcium oxalate monohydrate (COM) urinary stones (N = 36) of different composition by using the designed laser and 200-mu m-core low OH silica delivery fiber. The thulium fiber laser setting of 2.7 J pulse energy at the pulse rate of 10 Hz, pulse width of 90 ms, and peak power of 30 W is successful in breaking human COM stones in a controlled manner at a fragmentation rate of 0.8 +/- 0.4 mg/s, with almost uniform fragments of particle size less than 1.6 mm. During the stone fragmentation, the stone displacement (retropulsion effect) is less than 15 mm, even for the fragmented stone mass of 15 +/- 5 mg. (C) 2019 Optical Society of America

Item Type: Article
Subjects: Processing Science
Divisions: Fiber Optics and Photonics
Depositing User: Bidhan Chaudhuri
Date Deposited: 15 Nov 2019 12:00
Last Modified: 15 Nov 2019 12:00

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