High-power 2.1 μm Ho:Lu1.5Y1.5Al5O12 laser in-band pumped by a Tm fiber laser

Abstract

We report on a highly efficient Ho:LuYAG laser inband pumped by a high power narrow linewidth Tm fiber laser at 1907 nm. Lasing wavelength of the mixed crystal laser centered at 2124 or 2093 nm depending on the transmittance of the output coupler. With 1.0 at.% Ho 3+ -doped LuYAG crystal and an output coupler of 8% transmission, the laser yielded 21 W of continuous-wave output power at 2124 nm for 35 W of incident pump power, corresponding to a slope efficiency with respect to incident pump power of 61.5%.

High Power Ho:YAP Laser With 107 W of Output Power at 2117 nm

“…In-band pumping Ho doped materials between 5 I 8 and 5 I 7 levels has minimal thermal loading due to the inherent high quantum efficiency, making it attractive approach to obtain ∼2.1 μm lasers. So far, high power and efficient laser operation of Ho 3+ -doped Ho:YAG [8]- [10], Ho:LuYAG [11], [12], Ho:LuAG [13]- [15], Ho:YLF [16] and Ho:LLF [17] lasers have been successfully demonstrated. Employing four high power Tm:YLF laser pump sources and an oscillator containing two pieces of Ho:YAG in tandem, over 100 W of CW output has been generated with a slope efficiency of ∼68% [9].…”

Energy level systems and transitions of Ho:LuAG laser resonantly pumped by a narrow line-width Tm fiber laser

“…In high power laser applications, these will significantly increase the thermal loading and reduce the effective upper level lifetime [12,[18][19][20]. Due to very low quantum defect, inband pumping (resonant pumping 5 I 8 → 5 I 7 ) with Tm-doped solid state lasers [9,11,21,22], Tm fiber lasers [5,7,8,10,14,23,24] and 1.9 μm diode lasers [13] can overcome the energy-sharing problem in the Tm and Ho co-doped system, improve the slope efficiency, reduce the waste heat and encourage the good beam quality. In this paper, Ho:LuAG ceramic laser resonantly pumped by a Tm fiber laser was presented.…”

“…In this paper, Ho:LuAG ceramic laser resonantly pumped by a Tm fiber laser was presented. The tunable Tm fiber with a volume Bragg grating (VBG) was wavelength-locked at ~1907 nm, which had been used in our early Ho:YAG ceramic laser experiments [23,25]. Several recent publications about the Ho:LuAG laser materials, including single crystals grown by the Czochralski method [16,17] and ceramics fabricated by a reactive sintering method under vacuum [5,8], have been presented.…”

High repetition rate, Q-switched Ho:YAG laser resonantly pumped by a 20 W linearly polarized Tm: fiber laser

“…In recent years, high efficiency Ho oscillators in different configurations based on several hosts as YAG [16,17], YLF [18,19], YAP [20], LuAG [21], LLF [22], LSO [23], ceramic [24], and silica fiber [25,26] have been developed and reported. If we are talking about Ho:YAG lasers, it seems that diode-pumped Tm-doped bulk lasers [27,28] and Tm-doped fiber lasers [29] seem to be the most attractive sources for direct pumping.…”