Alo-3

We report on the continuous-wave (CW) and mode-locked (ML) laser performance of an Yb3+-doped yttrium-gadolinium orthoaluminate crystal, Yb:(Y,Gd)AlO3. Pumping by a single-transverse-mode fiber-coupled 976 nm InGaAs laser diode, the maximum output power in the CW regime amounted to 429 mW at 1041.8 nm corresponding to a slope efficiency of 51.1% and a continuous wavelength tuning across 84 nm (1011-1095 nm) was achieved. The self-starting ML operation of the Yb:(Y,Gd)AlO3 laser was stabilized by a semiconductor saturable absorber mirror. Soliton pulses as short as 43 fs were generated at 1052.3 nm with an average output power of 103 mW and a pulse repetition rate of ~70.8 MHz. To the best of our knowledge, our result represents the first report on the passively mode-locked operation of a Yb:(Y,Gd)AlO3 laser, and the shortest pulse duration ever achieved from any Yb3+-doped orthorhombic perovskite aluminate crystals.

The suitable choice of an activator and host combination is essential for synthesizing very sensitive thermoluminescence phosphors. In addition, conspicuous synthesis variables must be optimized to achieve the maximal response. The research presented herein shows that the most recommendable conditions to improve the thermoluminescence response of beta irradiated Gd1-xEuxAlO3 phosphors were: x = 0.02 for europium stoichiometry and 1500 °C for the calcination temperature. The glow curve recorded for the most sensitive phosphor was partially erased by photo-bleaching, and thus, should yield optically stimulated luminescence.

For the first time, to the best of our knowledge, the use of Nd3+ codoping for enhancing the ~4.0 μm emission from the Ho3+:5I5 → 5I6 transition was investigated in a Ho3+, Nd3+-codoped Gd0.1Y0.9AlO3 [(Y,Gd)AlO3] crystal [Ho/Nd:(Y,Gd)AlO3]. In this study, the ~4.0 μm emission characteristics and energy transfer were investigated in detail, and it was found that the codoped Nd3+ ions in the Ho/Nd:(Y,Gd)AlO3 crystal significantly enhanced the Ho3+:~4.0 μm emission, depopulated the lower laser level of Ho3+:5I6, and had little effect on the higher laser level of Ho3+:5I5. It was also found that the energy transfer efficiency from Nd3+:4F3/2 to Ho3+:5I5 was as high as 43.0%, indicating that Nd3+ ions can be used as an effective sensitizer for Ho3+ ions and that Ho/Nd:(Y,Gd)AlO3 crystal has the potential to be pumped by a commercialized InGaAs laser diode (LD). These results suggest that Ho/Nd:(Y,Gd)AlO3 crystals are likely to become attractive hosts for developing solid-state lasers at around 4.0 μm under a conventional 808 nm LD pump.