A vacuum-cored hollow waveguide has been found to transmit 1064-nm, Q-switched Nd:YAG laser pulses. With this scheme, laser-induced air breakdown was completely suppressed, and the laser-induced damage threshold of the waveguide's inner coating was significantly increased. With a 1-m-long, 1-mm inner-diameter, cyclic olefin polymer–coated silver hollow waveguide, the maximum transmitted laser energy was as great as 158 mJ/pulse (20.1 J/cm<sup>2</sup>), at a repetition rate of 10 Hz in a 90°-bent waveguide condition. The corresponding transmitted peak laser power was 17.6 MW. With the transmitted laser pulses, deep ablation of myocardium tissues was demonstrated <i>in vitro</i>.
© 2000 Optical Society of America
(060.2390) Fiber optics and optical communications : Fiber optics, infrared
(140.3440) Lasers and laser optics : Laser-induced breakdown
(140.3540) Lasers and laser optics : Lasers, Q-switched
(170.1020) Medical optics and biotechnology : Ablation of tissue
Shunichi Sato, Hiroshi Ashida, Tsunenori Arai, Yi-Wei Shi, Yuji Matsuura, and Mitsunobu Miyagi, "Vacuum-cored hollow waveguide for transmission of high-energy, nanosecond Nd:YAG laser pulses and its application to biological tissue ablation," Opt. Lett. 25, 49-51 (2000)