High Power Laser Science and Engineering, Volume. 6, Issue 1, 01000e11(2018)
Scaling diode-pumped, high energy picosecond lasers to kilowatt average powers
Fig. 1. Summary of diode-pumped, high energy/high average power, short pulse lasers. Demonstrated, diode-pumped,
Fig. 2. (a) Laser system diagram. The output of a diode-pumped, mode-locked bulk Yb:KYW oscillator is stretched by a grating stretcher and amplified to the millijoule level by a Yb:YAG regenerative amplifier. These seed pulses are subsequently amplified by a chain of two high power cryogenic amplifiers, and are compressed in vacuum by a dielectric grating pair. (b) Panoramic photograph of the high energy, high average power laser.
Fig. 3. (a) Layout of the 500 Hz repetition rate, 100-mJ-level, cryogenic amplifier. (b) Measured pulse energy as a function of total pump energy at 500 Hz repetition rate. (c) Spectrum of the amplified pulses showing a bandwidth of 0.43 nm FWHM. (d) SHG autocorrelation of the compressed, 100 mJ pulses at 500 Hz repetition rate. The sech
Fig. 4. (a) Measured pulse energy exiting the 100-mJ-level cryogenic amplifier at 1 kHz repetition rate. (b) 30 min continuous operation at 1 kHz. A mean energy of 67 mJ with RMS fluctuation of 0.6% was measured over this 1.8 million consecutive shots.
Fig. 5. (a) Layout of the high repetition rate, 1.5 J amplifier. (b) Photo of the enclosed amplifier, which occupies a table space of just over
Fig. 6. (a) Measured laser pulse energy exiting the main amplifier at 500 Hz repetition rate as a function of combined pump energy. (b) Amplified pulse energy over 30 min of continuous operation at 500 Hz repetition rate. A mean energy of 1.4 J was measured with an RMS fluctuation of 0.75%. (c) M
Fig. 7. (a) Schematic of the Mach–Zehnder interferometer used to make the thermal wavefront measurements. Millijoule-level,
Fig. 8. Interferograms obtained for average pump power of (a) 0.63, (b) 0.70, (c) 1.04, and (d) 1.53 kW, respectively. (e–h) Calculated thermally deformed wavefront maps from these interferograms. A reference wavefront measured with no pump power was subtracted in each case, resulting in only the thermal contribution. All maps are plotted on the same scale. (i–l) 3D surface plots of the wavefronts.
Fig. 9. Thermal focusing power as a function of average pump power calculated from the interferograms of Figure
Fig. 10. Measured amplified pulse energy at 1 kHz repetition rate as a function of total pump energy. The pump pulse duration was 0.5 ms, and the amplifier was seeded with about 65 mJ pulses (see Figure
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Brendan A. Reagan, Cory Baumgarten, Elzbieta Jankowska, Han Chi, Herman Bravo, Kristian Dehne, Michael Pedicone, Liang Yin, Hanchen Wang, Carmen S. Menoni, Jorge J. Rocca. Scaling diode-pumped, high energy picosecond lasers to kilowatt average powers[J]. High Power Laser Science and Engineering, 2018, 6(1): 01000e11
Special Issue: DIODE PUMPED SOLID STATE LASERS
Received: Dec. 3, 2017
Accepted: Jan. 3, 2018
Published Online: Jul. 3, 2018
The Author Email: Brendan A. Reagan (brendan.reagan@colostate.edu)