A diode-cladding-pumped dual wavelength Q-switched Ho3+-doped fluoride cascade fiber laser operating in the mid-infrared is demonstrated. Stable pulse trains from the I65→I75 and I75→I85 laser transitions were produced, and the μs-level time delay between the pulses from each transition was dependent on the pump power. At maximum pump power and at an acousto-optic modulator repetition rate of 25 kHz, the I65→I75transition pulse operated at 3.005 μm, a pulse energy of 29 μJ, and a pulse width of 380 ns; the I75→I85 transition pulse correspondingly produced 7 μJ pulse energy and 260 ns pulse width at 2.074 μm. To the best of our knowledge, this is the first demonstration of a Q-switched fiber laser operating beyond 3 μm.
© 2012 Optical Society of America
Lasers and Laser Optics
Original Manuscript: March 6, 2012
Revised Manuscript: April 12, 2012
Manuscript Accepted: April 12, 2012
Published: June 4, 2012
Jianfeng Li, Tomonori Hu, and Stuart D. Jackson, "Dual wavelength Q-switched cascade laser," Opt. Lett. 37, 2208-2210 (2012)