Sapphire fibers for 3-μm delivery systems

Er:YAG laser energy is highly absorbed by water, and therefore can provide excellent cutting precision with minimal thermal damage to surrounding tissue. Single crystal sapphire fibers are capable of transmitting Er:YAG laser energy with low loss and, additionally, they are chemically durable and bio-compatible. In this study, 300 micrometers diameter sapphire fibers were evaluated for use in surgical applications. Scattering and absorption losses, effective NA, and power handling capabilities were measured. The fibers had losses less than 1 dB/m, an effective NA of 0.2, and damage thresholds exceeding 1.2 kJ/cm2. The high damage thresholds were achieved only after a laser conditioning process at the proximal end of the fiber.