Based on phonon relaxation, a 12-at. % neodymium-doped YAG (Y<sub>3</sub>Al<sub>5</sub>O<sub>12</sub>) crystal fiber tip has been developed for photothermal conversion. The near-cylindrical tip, with an average diameter of 0.68 mm and a length of 1.8 mm, is fabricated on a 0.65-mm-thick 220-mm-long pure YAG single-crystal fiber by laser-heated growth. Pumped by an 810-nm wavelength diode laser with a pump power of less than 2 W, the temperatures of the tip reach 725 °C in air, 78 °C in egg white, and 79 °C in porcine liver, with acceptable reproducibilities and thermal response times. The photothermal conversion efficiency of the doped tip is approximately 89%, and the high stability of the tip is also proved. Experimental results show that the doped fiber tip is promising for laser thermotherapy applications.
© 2002 Optical Society of America
(060.2310) Fiber optics and optical communications : Fiber optics
(140.6810) Lasers and laser optics : Thermal effects
(160.5690) Materials : Rare-earth-doped materials
(170.0170) Medical optics and biotechnology : Medical optics and biotechnology
Limin Tong, Jingyi Lou, Yunfei Xu, Qingming Luo, Nan Shen, and Eric Mazur, "Highly Nd3+-doped Y3Al5O12 crystal fiber tip for laser thermotherapy," Appl. Opt. 41, 4008-4012 (2002)