Efficient cryo-cooled 2.7-μm Er3+:Y2O3 ceramic laser with direct diode pumping of the upper laser level

Abstract

Reported here is the first cryogenically-cooled performance of Er 3+ -doped Y2O3 laser based on 4 I 11/2 → 4 I 13/2 transitions. Laser material was diode-pumped directly into an upper laser manifold 4 I 11/2 in order to minimize quantum defect of this Mid-IR laser. CW output power of over 1.6 W at ∼ 2.7 μm was achieved with the 27.5% slope efficiency, which is approaching the quantum defect-limited efficiency value despite the marginal optical quality of the available laser sample.

Spectroscopic properties of Er-doped Y2O3ceramic related to mid-IR laser transition

“…This is done using the fact that: (2) and rad fl τ τ η = (3) where fl τ is the measured fluorescence lifetime and rad τ is the radiative lifetime. Using our calculated values for the A coefficients and the measured fluorescence lifetimes, we were able to determine the quantum efficiency for the 2.7 µm laser transition as a function of temperature.…”

“…We demonstrated 14 W of continuous wave (CW) optical power and nearly diffraction-limited output; and this output was strictly pump powerlimited [2]. Nearly quantum defect (QD)-limited 27.5% optical-to-optical slope efficiency [3] was largely achieved due to implementation of sufficiently narrowband high power pump source, a surface-emitting distributed feedback (SE-DFB) laser. The main limiting factors for power scaling of room temperature solid-state lasers are thermal effects, such as thermal lensing, induced polarization losses, and fracture [4].…”

Resonantly pumped continuous wave Er:YAP laser

“…Crystals with Er 3+ doping are attractive active materials for such developments [4][5]. Although YAG is an excellent host for Er lasers operating 1.64 and 2.70 µm [6][7][8], other crystal hosts were also employed for resonantly pumped Er laser action in the 1500-1700 nm emission wavelength band [9]. Jelínková [14].…”

1645 nm Q-Switched resonantly pumped Er:YAG laser

“…Transitions from the 4 I 13/2 to the 4 I 15/2 energy level in Er 3+ are well known to produce emission in the 1.5-1.6 µm region [3][4]. Er:YAG is an attractive laser medium for a hybrid laser owing to its robust thermomechanical properties [5][6][7].…”