title: Improved hollow-core photonic crystal fiber design for delivery of nanosecond pulses in laser micromachining applications.
abstract: We report the delivery of high-energy nanosecond pulses (approximately 65 ns pulse width) from a high-repetition-rate (up to 100 kHz) Q-switched Nd:YAG laser through the fundamental mode of a hollow-core photonic crystal fiber (HC-PCF) at 1064 nm. The guided mode in the HC-PCF has a low overlap with the glass, allowing delivery of pulses with energies above those attainable with other fibers. Energies greater than 0.5 mJ were delivered in a single spatial mode through the hollow-core fiber, providing the pulse energy and high beam quality required for micromachining of metals. Practical micromachining of a metal sheet by fiber delivery has been demonstrated.
authors.affiliation: Applied Optics and Photonics Group, Heriot Watt University, Edinburgh, UK. j.d.shephard@hw.ac.uk
authors.forename: Jonathan D
authors.initials: JD
authors.lastname: Shephard
authors.forename: Francois
authors.initials: F
authors.lastname: Couny
authors.forename: Phillip St J
authors.initials: PS
authors.lastname: Russell
authors.forename: Julian D C
authors.initials: JD
authors.lastname: Jones
authors.forename: Jonathan C
authors.initials: JC
authors.lastname: Knight
authors.forename: Duncan P
authors.initials: DP
authors.lastname: Hand
mesh_terms: D003460:Crystallization; D004735:Energy Transfer; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005336:Fiber Optic Technology / Q000295:instrumentation*; D007834:Lasers; D008420:Manufactured Materials; D008669:Metallurgy / Q000379:methods*; D008904:Miniaturization / Q000295:instrumentation / Q000379:methods; D017785:Photons