A 52-mJ Ho:YAG Master Oscillator and Power Amplifier with Kilohertz Pulse Repetition Frequency

Abstract

We report on a high energy, high repetition rate Ho:YAG master oscillator and power amplifier (MOPA), resonantly dual-end-pumped by Tm:YLF lasers at room temperature. At the pulse repetition frequency of 1 kHz, we demonstrate a maximum energy of 30 mJ per pulse with a 28.2 ns pulse width in a Ho:YAG oscillator system resonantly double-end-pumped by Tm:YLF lasers. A maximum energy of 52 mJ per pulse with a 30.5 ns pulse width is achieved in the Ho:YAG amplifier, corresponding to a peak power of approximately 1.7 MW. The output wavelength is at 2090.6 nm and 2096.9 nm, and a beam quality factor of 𝑀 2 ∼2.1 is achieved.

Narrow‐linewidth injection‐locked Ho:YAG laser by using thulium‐doped fiber laser as pumping source

“…Ho‐doped crystal with yttrium aluminum garnet (YAG) as host material is an excellent candidate of 2 μm gain medium because it has good thermomechanical property and is easy to grow with high quality 17 . More importantly, the isotropic Ho:YAG crystal possesses magneto‐optical Faraday effect, resulting in the convenient, stable, and high‐power nonplanar ring oscillator (NPRO) based on Ho:YAG crystal can be used in a 2 μm injection‐locked laser system as the seed source 18 .…”

“…16 Ho-doped crystal with yttrium aluminum garnet (YAG) as host material is an excellent candidate of 2 μm gain medium because it has good thermomechanical property and is easy to grow with high quality. 17 More importantly, the isotropic Ho:YAG crystal possesses magneto-optical Faraday effect, resulting in the convenient, stable, and high-power nonplanar ring oscillator (NPRO) based on Ho:YAG crystal can be used in a 2 μm injection-locked laser system as the seed source. 18 In 2012, Dai et al achieved an injection-locked Q-switching Ho:YAG laser, pumped by a 1.91 μm Tm:YLF solid-state laser, with an output energy of 7.6 mJ for 132 ns pulse duration at a pulse repetition frequency (PRF) of 100 Hz.…”

Single-longitudinal-mode operation of a 2.09 μm holmium laser with anti-misalignment corner cube ring cavity

“…Among the gain materials for 2 µm laser output, Ho:YAG crystal shows isotropic properties and its benefits include large gain cross-section, high hardness and high heat conductivity [11,12]. Therefore, these excellent properties make Ho:YAG crystal to be candidate of gain medium for 2 µm high power and high efficiency laser output.…”