We report what is to our knowledge the first delivery of nanosecond laser pulses through flexible fibers to produce optical sparks in atmospheric-pressure gases. Our work employs a Nd:YAG laser beam (1.064 µm) delivered through a cyclic olefin polymer-coated silver hollow fiber. We studied the beam properties at the fiber exit as a function of the fiber launch geometry. We found that for a low-angle launch (∼0.01 rad half-angle), the exit beam has relatively high optical intensity (∼2 GW/cm²) and low light divergence (∼0.01 rad half-angle) and allows downstream spark formation. The effect of fiber bending on the exit beam and on the ability to make sparks is also investigated.
© 2005 Optical Society of America
A. P. Yalin, M. DeFoort, B. Willson, Y. Matsuura, and M. Miyagi, "Use of hollow-core fibers to deliver nanosecond Nd:YAG laser pulses to form sparks in gases," Opt. Lett. 30, 2083-2085 (2005)