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Proceedings Paper

Improvement of solid state Er:YAG pulse laser performance for use in medicine
Author(s): Maris Ozolinsh; Karl Stock; Raimund Hibst; Rudolf Steine; Maris Kundzinsh
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Paper Abstract

The large quadratic electro-optic effect of PLZT ceramics allows to design small size modulators for the solid state infrared Er:YAG laser (lasing at (lambda) equals 2.94 micrometers - the most pronounced absorption band of water), which has found application in medicine for efficient ablation of hard and soft tissues. In the free-running mode, the Er:YAG laser emits spikes that form the pulse envelope with duration of 150 - 800 microsecond(s) . An extracavity PLZT 8.5/65/35 ceramics modulator (aperture of 4 X 6 mm2 and length of 18 mm) was used to obtain (Pi) -shaped segments with the rise and decay times less than 5 microsecond(s) . That allows to reduce considerably the fraction of the pulse energy below the ablation threshold so avoiding undesirable heating of tissues. The halfwave voltage of such modulator was 1350 V with an additional DC bias of 300V. The contrast ration K > 15:1. The Q-switching technique was applied to obtain high intensity small duration monopulses using modulators of the same PLZT 8.5/65/35 ceramics. PLZT ceramics Q-switches (tested in two schemes - as a (lambda) /4 switch placed perpendicular to the beam with a length of 6mm without antireflection coatings; and as a (lambda) /2 switch with a length of 3 mm placed at the Brewster angle) allowed to obtain monopulses with the energy of 5 - 8 mJ and with a pulse width of 150 ns.

Paper Details

Date Published: 15 January 1999
PDF: 5 pages
Proc. SPIE 3570, Biomedical Sensors, Fibers, and Optical Delivery Systems, (15 January 1999); doi: 10.1117/12.336934
Show Author Affiliations
Maris Ozolinsh, Univ. of Latvia (Latvia)
Karl Stock, Univ. of Ulm (Germany)
Raimund Hibst, Univ. of Ulm (Germany)
Rudolf Steine, Univ. of Ulm (Germany)
Maris Kundzinsh, Univ. of Latvia (Latvia)

Published in SPIE Proceedings Vol. 3570:
Biomedical Sensors, Fibers, and Optical Delivery Systems
Francesco Baldini; Nathan I. Croitoru; Martin Frenz; Ingemar Lundstroem; Mitsunobu Miyagi; Riccardo Pratesi; Otto S. Wolfbeis, Editor(s)

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