Transmission of free-running and Q-switched erbium: YSGG laser radiation through sapphire and germanium fibers

Abstract

The Erbium:YAG (2 = 2.94 tm) and Erbium:YSGG (X 2.79 pm) lasers are cunently being used for tissue ablation in several medical specialties, including dermatology, ophthalmology and dentistry. Some of these applications may benefit from the availability of an optical fiber capable of delivering sufficient short-pulse, Q-switched Erbium laser energy for precise and rapid ablation of hard and soft tissues. Fiber transmission studies were conducted using both free-running (300 ps) and Q-switched (500 ns) Er:YSGG laser pulses delivered at 3 Hz through 1-meter-long samples of 450-jim germanium oxide and 425-tm sapphire optical fibers. Fiber optic transmission of free-running Er:YSGG laser radiation averaged 76% and 88% for the germanium and sapphire fibers (n = 7), respectively.Transmission of Q-switched Er:YSGG laser radiation averaged 57% and 65% for the germanium and sapphire fibers (n = 7), respectively. Fiber optic transmission of Q-switched pulse energies as high as 42 mJ was achieved through the fibers. However, damage at the input ends of the fibers began to occur at input I output pulse energies above 40 mJ I 25 mJ (n = 2), respectively. Both germanium oxide and sapphire optical fibers are capable of transmitting sufficient free-running and Q-switched Er:YSGG laser radiation for hard and soft tissue ablation.