Highly efficient Er:YAP laser with 6.9 W of output power at 2920†nm.

We report on the efficient high-power operation of a laser-diode-pumped Er3+-doped yttrium aluminum perovskite (Er:YAP) laser in the 3 µm spectral region at room temperature. 6.9 W of continuous-wave (CW) output power was obtained at 2920 nm. The slope efficiency was as high as 30.6% with respect to the absorbed pump power, which is close to the quantum defect limit (33.4%). To the best of our knowledge, this is the highest CW output power generated from 3 µm Er3+-doped solid state lasers at room temperature. Furthermore, our analysis has shown that more than 10 W of output power based on Er:YAP is possible by further mitigating the thermal lens effect.

Efficient Pr:YAlO3 lasers at 622†nm, 662†nm, and 747†nm pumped by semiconductor laser at 488†nm.

We report laser operation of Pr:YAlO3 pumped by a frequency-doubled optically pumped semiconductor laser. Continuous-wave laser oscillations at around 622 nm, 662 nm, and 747 nm were demonstrated in plano-concave or/and plano-plano cavities. The maximum slope efficiencies were found to be 37%, 35%, and 59%, respectively, which are record-high values for Pr:YAlO3 lasers. Furthermore, lasing at 622 nm was demonstrated at room temperature for the first time to the best of our knowledge.

2.92-µm high-efficiency continuous-wave laser operation of diode-pumped Er:YAP crystal at room temperature.

Mid-infrared lasers have attracted attention for application to the fields of medicine and industry. In this study, we demonstrate continuous-wave laser operation of a diode-pumped 5 at % Er-doped YAlO3 (YAP) single-crystal lasing at 2.92 µm with near-quantum-defect slope efficiency at room temperature. A high slope efficiency of 31% is achieved with a maximum output power of 0.674 W for a cavity length of 18 mm and an output coupler transmittance of 2.5%. This efficiency is 94% of the theoretical quantum-defect efficiency. Our results indicate that Er:YAP lasers can potentially be utilized to realize high-power mid-IR lasing.

High detection efficiency scintillating fiber detector for time-resolved measurement of triton burnup 14 MeV neutron in deuterium plasma experiment.

The behavior of the 1 MeV triton has been studied in order to understand the alpha particle confinement property in the deuterium operation of toroidal fusion devices. To obtain time evolution of the deuterium-tritium (D-T) neutron emission rate where the secondary DT neutron emission rate is approximately 1012 n/s, we designed two high detection efficiency scintillating fiber (Sci-Fi) detectors: a 1 mm-diameter scintillation fiber-based detector Sci-Fi1 and a 2 mm-diameter scintillation fiber-based detector Sci-Fi2. The test in an accelerator-based neutron generator was performed. The result shows that the directionality of each detector is 15° and 25°, respectively. It is found that detection efficiency for DT neutrons is around 0.23 counts/n cm2 for the Sci-Fi1 detector and is around 1.0 counts/n cm2 for the Sci-Fi2 detector.