Kevin J. Snell

Efficient 1645-nm Er:YAG laser

We report a resonantly fiber-laser-pumped Er:YAG laser operating at the eye-safe wavelength of 1645 nm, exhibiting 43% optical efficiency and 54% incident slope efficiency and emitting 7-W average power when repetitively Q switched at 10 kHz. To our knowledge, this is the best performance (conversion efficiency and average power) obtained from a bulk solid-state Q-switched erbium laser. At a 1.1-kHz pulse repetition frequency the laser produces 3.4-mJ pulses with a corresponding peak power of 162 kW. Frequency doubling to produce 822.5-nm, 4.7-kW pulses at 10 kHz was performed to demonstrate the lasers utility.

5-W repetitively Q-switched Er:LuAG laser resonantly pumped by an erbium fiber laser

We report a high-average-power, near-diffraction-limited Er:LuAG laser generating 5 W of power at 1.648 microm in either cw or repetitively Q-switched operation. When the laser is Q switched at 9 kHz, we measure 0.52 mJ/pulse. The laser is end pumped by a 20-W erbium fiber laser and achieves >30% optical conversion efficiency and >40% incident slope efficiency. This is, to our knowledge, the highest performance (average power and conversion efficiency) obtained from a bulk solid-state erbium laser.

Diode-pumped, High-Power CW and Modelocked Nd:YLF Lasers

Using a side-pumped, Nd:YLF slab laser design, we have obtained a TEM00- mode output power of 25.7 W with 43.5% optical efficiency and a multimode output of nearly 36 W with 46% efficiency. As an amplifier of a SESAM-mode-locked laser, the same design has allowed us to generate, with 4.5-ps pulses at a 100-MHz rate, 15.7 W of average power in the fundamental and 2.9 W of power at the fourth harmonic.

High-peak-power erbium lasers resonantly pumped by fiber lasers

Challenges typically associated with efficient operation of bulk solid-state erbium lasers operating on the eyesafe (4I13/2 → 4I15/2) transition have been effectively overcome using a high-brightness fiber laser as a pump source. We report exceptional performance in a variety of laser hosts resonantly pumped by a cw, high-average-power erbium fiber laser. Herein we present results from resonantly pumped erbium-doped YAG, LuAG, YLF, YAlO3, and YVO4, in cw and repetitively Q-switched operation. Most notable results include 9.5 W of near-diffraction-limited output from an Er:YAG laser at 1.645 μm, Q-switched at 10 kHz with 40 ns pulsewidth (25 kW peak power) as well as 3.4 μJ/pulse with 21 ns pulses at 1.1 kHz (160 kW peak). We have achieved overall optical conversion efficiency greater than 50% with incident slope efficiency >60%. This is, to our knowledge, the highest performance (average power and conversion efficiency) obtained from a bulk solid-state Q-switched erbium laser. To demonstrate the utility of such sources, we also present results from second harmonic generation to 822nm, as well as a periodically poled lithium niobate optical parametric oscillator generating tunable 2.5 - 3.8 micron output.

High-average power, high-repetition rate, side-pumped Nd:YVO/sub 4/ slab laser MOPA system

Greater than 50 W average power at a 50 kHz repetition rate has been obtained in a Q-switched, diode-pumped Nd:YVO/sub 4/ master oscillator/power amplifier (MOPA) system operating at 1064 nm and greater than 23 W average power operating at 1342 nm with near-diffraction limited beam quality.

Athermal, lightweight, diode-pumped, 1-micron transmitter

Design and projected performance of a lightweight, 1064 nm, laser transmitter is described. A 40 mJ, diode side-pumped Nd:YAG zig-zag slab oscillator is configured to operate on either of two Nd:YAG absorption bands (795 nm or 807 nm) to provide stable operation over a 100°C temperature range, using minimal power for diode wavelength stabilization.

RGB optical parametric oscillator source for compact laser projection displays

A compact and efficient laser source is required as an enabling technology for laser projection displays. We discuss a scalable green-pumped, non-critically phase- matched LBO optical parametric oscillator (OPO) which simultaneously generates red and blue wavelengths that are ideal for display applications. Pumping the OPO with 9.7 W of 523 nm green light from a frequency-doubled, diode-pumped Nd:YLF oscillator/amplifier laser system has resulted in a measured 4.0 W of 896 nm signal power and an estimated idler power of 2.8 W. The signal was extra-cavity frequency doubled to produce 1.10 W of blue light at 448 nm. Intra- cavity frequency doubling of the idler produced 1.95 W of red light at 628 nm.