Wave Tm Research Articles

Diode End Pumped Continuous Wave and Graphene Q-Switched Tm:LGGG Lasers

A detailed investigation was conducted on continuous wave, wavelength tunable, and graphene passively Q-switched (PQS) lasers of Tm:LGGG crystal. In continuous wave operation, a maximum average output power of 2.26 W at 2003 nm was obtained under the absorbed power of 12.1 W, giving an optical-to-optical conversion efficiency of 18.7% and a slope efficiency of 23.6%. By using a quartz plate, the emission spectrum could be tuned from 1907.5 to 2055.9 nm, corresponding to a full-width at half-maximum (FWHM) of 83 nm. Dual-wavelength operation could be obtained by rotating the quartz plate at an appropriate angle. In graphene PQS regime, the Tm:LGGG laser produced a 1.29- $\mu \text{s}$ pulse under the pulse repetition frequency of 43.9 kHz, corresponding to a pulse energy of 3.19 $\mu \text{J}$ .

Electrochemical reduction of rare-earth chelates with certain ?-diketones

Chelates of a number of lanthanides (Pr, Eu, Tb, Dy, Er, Tm, Yb) and certain other metals (Cu, Ni, Co, Tl) with the β-diketones dipivaloylmethane and trifluoroacetylcamphor are reduced electrochemically for the first time in aprotic medium (DMF). The nature of the lowest unoccupied molecular orbital, into which the first electron enters, is demonstrated to be centered on the ligand and not the metal. A difference is observed in the polarographic behavior of the cerium subgroup complexes (Pr, Eu), which are reduced in one step, and those of the yttrium subgroup, which exhibit two waves (Tb, Er, Yb) of a distinctly doubled wave (Tm, Dy).