Efficient 1.7 µm pumping of 2 µm thulium lasers.

Solid-state 2 µm lasers based on thulium-doped active media Tm:YAG, Tm:YAP, and Tm:YLF were investigated under 1.7 µm resonant diode pumping. In contrast with standard 0.8 µm pump wavelength, a high slope efficiency was achieved, up to 80% in the case of Tm:YAP and Tm:YLF, nearing a quantum limit without relying on Tm3+-Tm3+ cross-relaxation energy transfer. Low thermal load allowed for stable continuous-wave operation with good beam quality and output power up to 6 W (Tm:YAG, Tm:YLF), and 8 W (Tm:YAP).

Cubic octanuclear aluminum fluoride phosphonate.

A crystalline complex [Al8F12{(CH3)2C(NH3)PO3}12] (1) was isolated from the supernatant of the hydrothermal reaction of gibbsite Al(OH)3 with 1-amino-1-methyl-ethylphosphonic acid (AIPA) and the HF mineralizer. The single-crystal X-ray diffraction analysis revealed a highly symmetrical cubic Al8F12 core with aluminum atoms at the corners, bridging fluorides spanning all edges, and 12 bidentate bridging phosphonate ligands completing the octahedral coordination sphere of aluminum centers. The stability of the complex in solution was established by electrospray mass spectrometry and the high molecular symmetry (Th) was reflected in the appearance of single resonances in the 1H, 19F, and 31P NMR spectra.